WO2020230255A1 - Ignition device - Google Patents

Ignition device Download PDF

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Publication number
WO2020230255A1
WO2020230255A1 PCT/JP2019/019038 JP2019019038W WO2020230255A1 WO 2020230255 A1 WO2020230255 A1 WO 2020230255A1 JP 2019019038 W JP2019019038 W JP 2019019038W WO 2020230255 A1 WO2020230255 A1 WO 2020230255A1
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WO
WIPO (PCT)
Prior art keywords
switching element
secondary current
control device
control
internal combustion
Prior art date
Application number
PCT/JP2019/019038
Other languages
French (fr)
Japanese (ja)
Inventor
中川　光
裕一 村本
尚紀 片岡
成瀬　祐介
棚谷　公彦
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2021519092A priority Critical patent/JP7055243B2/en
Priority to PCT/JP2019/019038 priority patent/WO2020230255A1/en
Publication of WO2020230255A1 publication Critical patent/WO2020230255A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P15/00—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits
    • F02P15/10—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits having continuous electric sparks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P3/00—Other installations

Definitions

  • the present application relates to an ignition device.
  • Patent Document 1 by turning on and off the second primary winding at high speed during the discharge period, it is possible to prevent the secondary current from continuing to increase and prevent the secondary current from becoming too large. There is.
  • Patent Document 1 by frequently turning off the second primary winding, it is possible to prevent the secondary current from becoming too large. ing.
  • a counter electromotive force is generated in the second primary winding, and the secondary current is rapidly reduced to the level before the current superposition. Therefore, every time the second primary winding is turned off, the effect of stabilizing the discharge is impaired due to the increase in the discharge current, and the discharge may be interrupted due to the in-cylinder flow or the like, so that the ignitability is sufficiently improved. It wasn't planned.
  • an ignition device capable of appropriately increasing the secondary current so that the secondary current does not increase or decrease too much by energizing the second primary winding during the discharge period is desired.
  • the ignition device is A first primary winding in which an energizing magnetic flux is generated by energization, a second primary winding in which an energizing magnetic flux is generated in a direction opposite to the energizing magnetic flux of the first primary winding by energization, and the first winding.
  • a transformer having a primary winding and a secondary winding magnetically coupled to the second primary winding to supply discharge energy to the ignition plug.
  • the second switching element is turned on, It is provided with a control device for turning on / off the first switching element during the on period of the second switching element.
  • the ignition device since the second primary winding is energized during the spark discharge, additional magnetic energy is supplied to the secondary winding, and the discharge current (secondary current) flowing between the electrodes is generated. To increase. As a result, the spark discharge is strengthened, and the ignitability of the air-fuel mixture and the extensibility of the spark discharge can be strengthened. Further, when the first switching element is turned on during the on period of the second switching element, the first primary winding generates an energizing magnetic flux in the direction opposite to the energizing magnetic flux of the second primary winding. However, the magnetic energy added to the secondary winding is weakened, and the secondary current can be reduced.
  • the first switching element is turned on while the second switching element is turned on, no back electromotive force is generated in the second primary winding, and the secondary current is gradually reduced. Can be done. Therefore, by turning the first switching element on and off during the on period of the second switching element, the secondary current can be prevented from increasing too much and not decreasing too much, and the secondary current can be appropriately increased. it can. Therefore, it is possible to suppress an increase in electrode wear of the spark plug while improving the ignitability.
  • FIG. It is a schematic circuit diagram of the ignition device which concerns on Embodiment 1.
  • FIG. It is a hardware block diagram of the control device which concerns on Embodiment 1.
  • FIG. It is a flowchart explaining the process of on / off control of the 1st switching element which concerns on Embodiment 1.
  • FIG. It is a time chart for demonstrating the control behavior which concerns on Embodiment 1.
  • FIG. It is a figure which shows the setting example of the on-off plan data which concerns on Embodiment 2.
  • FIG. It is a time chart for demonstrating the control behavior which concerns on Embodiment 2.
  • FIG. 1 is an electric circuit diagram showing a basic configuration of the ignition device 10 according to the first embodiment.
  • the ignition device 10 includes a spark plug 5, a transformer 3, a first switching element 1, a second switching element 2, a secondary current detection circuit 7, a control device 4, and the like.
  • the spark plug 5 has a first electrode 5A and a second electrode 5B facing each other through a gap, and ignites a combustible air-fuel mixture in a combustion chamber.
  • the first electrode 5A and the second electrode 5B of the spark plug 5 are arranged in the combustion chamber (inside the cylinder) of the internal combustion engine.
  • the first electrode 5A is connected to the secondary winding 3c, and the second electrode 5B is connected to the ground.
  • the transformer 3 the first primary winding 3a in which the energization magnetic flux is generated by energization and the second primary winding 3b in which the energization magnetic flux in the direction opposite to the energization magnetic flux of the first primary winding 3a is generated by energization.
  • a secondary winding 3c that is magnetically coupled to the first primary winding 3a and the second primary winding 3b to supply discharge energy to the spark plug 5.
  • the first primary winding 3a, the second primary winding 3b, and the secondary winding 3c are wound around a common iron core.
  • One end of the first primary winding 3a and the other end of the second primary winding 3b are made of the same DC power supply 6, and the other end of the first primary winding 3a is the first switching element. It is connected to the ground via 1, and one end of the second primary winding 3b is connected to the ground via the second switching element 2.
  • One end of the secondary winding 3c is connected to the first electrode 5A of the spark plug 5, and the other end of the secondary winding 3c is connected to the ground side.
  • the turns ratio between the first primary winding 3a and the secondary winding 3c determines the first switching element 1.
  • the voltage generated in the spark plug 5 when it is turned on and then turned off for the above time is set to be equal to or higher than the breakdown voltage of the spark plug 5, and is, for example, about 100. Since the transformer 3 and the first switching element 1 are configured like a flyback converter, a voltage at least twice the number of turns can be applied to the spark plug 5.
  • the voltage generated in the spark plug 5 is set to be equal to or higher than the discharge maintenance voltage, and is, for example, about 200 to 400 times.
  • the number of turns of the second primary winding 3b is configured to be smaller than the number of turns of the first primary winding 3a, and the number of turns of the second primary winding 3b is the second. It becomes 1/2 to 1/4 of the primary winding 3a of 1. Therefore, the energizing magnetic flux of the first primary winding 3a is stronger than the energizing magnetic flux of the second primary winding 3b, and the first is being energized while the second primary winding 3b is energized.
  • the secondary current I2 can be reduced by energizing the primary winding 3a of the above. With such a configuration, the operation of the first switching element 1 can cause dielectric breakdown between the electrodes of the spark plug 5, and the operation of the second switching element 2 can maintain the discharge between the electrodes of the spark plug 5. It will be possible.
  • the first switching element 1 is a switching element that turns on / off the energization from the DC power supply 6 to the first primary winding 3a.
  • the drive signal S_sw1 output from the control device 4 is input to the first switching element 1, and the first switching element 1 is turned on and off by the drive signal S_sw1.
  • the second switching element 2 is a switching element that turns on / off the energization from the DC power supply 6 to the second primary winding 3b.
  • the drive signal S_sw2 output from the control device 4 is input to the second switching element 2, and the second switching element 2 is turned on and off by the drive signal S_sw2.
  • first switching element 1 and the second switching element 2 for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or the like is used. Diodes may be connected in antiparallel to each switching element.
  • IGBT Insulated Gate Bipolar Transistor
  • MOSFET Metal Oxide Semiconductor Field Effect Transistor
  • the first switching element 1 By turning on the first switching element 1 for a predetermined time (for example, about 2 ms to 10 ms) and then turning it off, dielectric breakdown occurs between the electrodes of the spark plug 5. At this time, the maximum current flowing through the first switching element 1 is about 5A to 20A. After dielectric breakdown occurs between the electrodes of the spark plug 5, the second switching element 2 is turned on for a predetermined time (for example, about 200 us to 3 ms) to add the electric discharge between the electrodes of the spark plug 5 while maintaining the discharge. Supply the current of. At this time, the maximum current flowing through the second switching element 2 is about 10 A to 50 A. Therefore, it is desirable that the current rated value of the second switching element 2 is larger than the current rated value of the first switching element 1.
  • a predetermined time for example, about 2 ms to 10 ms
  • Switching elements with a large current rating generally have low resistance when turned on. Therefore, it is possible to suppress excessive heat generation of the element due to electric current and element destruction due to transient heat generation. Further, since an element having a larger chip size generally has a larger current rating value, the same effect can be obtained if the chip size of the second switching element 2 is larger than the chip size of the first switching element 1.
  • the first switching element 1 is turned on / off (switched) during the on period of the second switching element 2. Therefore, it is desirable that the switching time (falling time, rising time, rising time, falling time) of the first switching element 1 is shorter than the switching time of the second switching element 2.
  • the first switching element 1 can be turned on and off at a high frequency, and it is easy to control to reduce the peak of the secondary current described later.
  • the short switching time also contributes to the reduction of switching loss.
  • the secondary current detection circuit 7 is a circuit for detecting the secondary current I2 flowing in the secondary winding 3c during the spark discharge of the spark plug 5.
  • the secondary current detection circuit 7 is a resistor (hereinafter, referred to as a secondary current detection resistor 7) connected in series on the discharge path of the secondary current I2.
  • the low voltage side terminal of the secondary current detection resistor 7 is connected to the ground, and the high voltage side terminal of the secondary current detection resistor 7 is connected to the other end of the secondary winding 3c.
  • the voltage of the high voltage side terminal of the secondary current detection resistor 7 is input to the control device 4.
  • the secondary current detection circuit 7 may be a current transformer or a Hall sensor arranged on the discharge path of the secondary current I2.
  • control device 4 is a control device for an internal combustion engine that controls an internal combustion engine. Each function of the control device 4 is realized by a processing circuit provided in the control device 4.
  • the control device 4 is a storage device 91 that exchanges data with an arithmetic processing unit 90 (computer) such as a CPU (Central Processing Unit) and an arithmetic processing unit 90 as a processing circuit.
  • An input circuit 92 for inputting an external signal to the arithmetic processing unit 90, an output circuit 93 for outputting a signal from the arithmetic processing unit 90 to the outside, and the like are provided.
  • the arithmetic processing device 90 includes an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. You may. Further, a plurality of arithmetic processing units 90 of the same type or different types may be provided, and each processing may be shared and executed.
  • the storage device 91 includes a RAM (Random Access Memory) configured to be able to read and write data from the arithmetic processing device 90, a ROM (Read Only Memory) configured to be able to read data from the arithmetic processing device 90, and the like. Has been done.
  • the input circuit 92 is connected to the secondary current detection circuit 7 and various sensors 21 of the internal combustion engine (crank angle sensor, cam angle sensor, intake air amount detection sensor, pressure sensor, water temperature sensor, power supply voltage sensor, etc.). It is equipped with an A / D converter or the like that inputs an output signal to the arithmetic processing device 90.
  • the output circuit 93 is connected to a first switching element 1, a second switching element 2, and various electric loads 22 (injectors, exhaust gas recirculation valves, etc.) of an internal combustion engine, and a control signal is transmitted from the arithmetic processing device 90 to these. It is equipped with a drive circuit that outputs. It is desirable that the cutoff frequency of the low-pass filter of the drive circuit connected to the first switching element 1 is set to 100 kHz or more.
  • the arithmetic processing unit 90 executes software (program) stored in the storage device 91 such as ROM, and controls the storage device 91, the input circuit 92, the output circuit 93, and the like. It is realized by cooperating with other hardware of the device 4.
  • the setting data such as the control setting data used by the control device 4 is stored in the storage device 91 such as the ROM as a part of the software (program).
  • the control device 4 determines the rotation speed of the internal combustion engine, filling efficiency (pressure information in the cylinder), cooling water temperature, exhaust gas recirculation rate, etc., based on the output signals of various input sensors. Detects the operating state of the internal combustion engine, calculates the ignition timing, target air-fuel ratio, fuel injection amount, control amount of the exhaust gas recirculation valve, etc. based on the operating state, and various types of internal combustion engines such as injectors and exhaust gas recirculation valves.
  • the electric load 22, the first switching element 1, the second switching element 2, and the like are driven and controlled.
  • the control device 4 turns on the first switching element 1 to turn on the energization of the first primary winding 3a, and then turns off the first switching element 1 to turn on the first primary winding 3a.
  • the power supply to the ignition plug 5 is turned off to generate a spark discharge in the spark plug 5.
  • the control device 4 calculates the energization period and ignition timing (ignition crank angle) of the first primary winding 3a.
  • the control device 4 determines the energization period and the ignition timing based on the operating state of the internal combustion engine.
  • the operating state of the internal combustion engine is the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the exhaust gas recirculation rate, and the like.
  • the control device 4 turns on the first switching element 1 during the energization period, energizes the first primary winding 3a, and then turns off the first switching element 1 at the ignition timing.
  • the energization of the first primary winding 3a is cut off, a high voltage is generated in the secondary winding 3c, and a spark discharge is generated in the spark plug 5.
  • the spark discharge continues until the magnetic energy stored in the iron core of the spark plug 5 is reduced.
  • the control device 4 turns on the second switching element 2 during the spark discharge period.
  • the second primary winding 3b is energized during the spark discharge, additional magnetic energy is supplied to the secondary winding 3c, and the discharge current (secondary current I2) flowing between the electrodes increases.
  • the spark discharge is strengthened, and the ignitability of the air-fuel mixture and the extensibility of the spark discharge are strengthened.
  • discharge current discharge current
  • the control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the control parameters of the on time and the off time of the second switching element 2 is set in advance. Calculate the on-time and off-time control parameters corresponding to the current operating state of the internal combustion engine.
  • the control parameter of the ON timing is the lower limit threshold value I2_thL of the secondary current I2.
  • the lower limit threshold value I2_thL is shared with the threshold value for turning off the first switching element 1 described later.
  • the control device 4 turns on the second switching element 2 when the detected value of the secondary current I2 becomes smaller than the lower limit threshold value I2_thL after the start of discharge.
  • the control parameter at the on time may be the elapsed time after the start of discharge, and the control device 4 may turn on the second switching element 2 when the elapsed time after the start of discharge reaches the threshold value. Good.
  • the control parameter for the off time is the off time after the start of discharge.
  • the control device 4 turns off the second switching element 2 when the elapsed time after the start of discharge reaches the off time.
  • the secondary current I2 means the absolute value of the secondary current I2. Further, “after the start of discharge” and “after the start of spark discharge” are after the first switching element 1 is turned off in order to generate spark discharge.
  • control parameters for the on time and the off time which are preset by a preliminary test or the like, are stored in the storage device 91 and read out.
  • the control device 4 may learn the control parameters of the on-time and the off-time by machine learning or the like, and use the learned values.
  • the operating conditions of the internal combustion engine are the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the internal combustion engine.
  • the compression ratio of the internal combustion engine is added when the internal combustion engine is provided with a mechanism capable of changing the compression ratio of the internal combustion engine.
  • the operating state of the internal combustion engine is the filling efficiency of the internal combustion engine, the rotation speed of the internal combustion engine, and the exhaust gas recirculation rate.
  • the control device 4 turns on / off the first switching element 1 during the on period of the second switching element 2.
  • the first primary winding 3a becomes the energizing magnetic flux of the second primary winding 3b.
  • Generates an energizing magnetic flux in the opposite direction weakens the magnetic energy added to the secondary winding 3c, and can reduce the secondary current I2.
  • the first switching element 1 is turned on with the second switching element 2 turned on, no counter electromotive force is generated in the second primary winding 3b, and the secondary current I2 is moderated. Can be reduced to.
  • the secondary current I2 can be prevented from increasing too much and not decreasing too much, and the secondary current I2 can be appropriately adjusted. Can be increased. Therefore, it is possible to suppress an increase in electrode wear of the spark plug while improving the ignitability.
  • the control device 4 detects the secondary current I2 based on the output signal of the secondary current detection circuit 7. Then, the control device 4 turns on / off the first switching element 1 based on the detected value of the secondary current I2 during the on period of the second switching element 2. According to this configuration, since it is based on the detected value of the secondary current I2, it is possible to increase the secondary current I2 appropriately and not to increase the secondary current I2 too much with high accuracy.
  • the control device 4 turns on the first switching element 1 when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH during the on period of the second switching element, and the first switching element 1 is turned on.
  • the detected value of the secondary current I2 becomes smaller than the lower limit threshold value I2_thL set to a value equal to or lower than the upper limit threshold value I2_thH after the switching element 1 is turned on, the first switching element 1 is turned off.
  • the lower limit threshold value I2_thL is set to a value smaller than the upper limit threshold value I2_thH, but it may be set to the same value.
  • the secondary current I2 can be accurately controlled within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
  • the set value of the upper limit threshold value I2_thH can control the suppression of increase in electrode wear of the spark plug, and the set value of the lower limit threshold value I2_thL can manage the improvement of ignitability.
  • the optimum set value of the upper limit threshold value I2_thH and the optimum set value of the lower limit threshold value I2_thL which can improve the ignitability and suppress the increase in electrode wear, change depending on the operating state of the internal combustion engine. For example, it is desirable to maintain a large discharge current under operating conditions in which the flow in the cylinder is large and the discharge is easily blown off. However, if the discharge current is excessively large, the life of the spark plug is shortened because the amount of electrode consumption is large even if the ignitability can be improved. Therefore, since there is a trade-off relationship between ignitability and electrode wear, it is desirable to determine an appropriate secondary current (discharge current) value based on the operating state of the internal combustion engine.
  • control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the upper limit threshold value I2_thH and the lower limit threshold value I2_thL is set in advance, and refers to the upper limit threshold value I2_thH and the upper limit threshold value I2_thH corresponding to the current operating state of the internal combustion engine.
  • the lower limit threshold I2_thL is calculated.
  • the operating conditions of the internal combustion engine are the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the internal combustion engine.
  • the compression ratio of the internal combustion engine is added when the internal combustion engine is provided with a mechanism capable of changing the compression ratio of the internal combustion engine.
  • the operating state of the internal combustion engine is the filling efficiency of the internal combustion engine, the rotation speed of the internal combustion engine, and the exhaust gas recirculation rate.
  • the upper limit threshold value I2_thH and the lower limit threshold value I2_thL which are preset by a preliminary test or the like, are stored in the storage device 91 and read out.
  • the control device 4 determines the current value at which ignition was possible without misfire, learns the upper limit threshold value I2_thH and the lower limit threshold value I2_thL by machine learning or the like based on the determined current value, and uses the learned value. You may.
  • step S101 the control device 4 determines whether or not the second switching element 2 (drive signal S_sw2) is turned on (1).
  • the control device 4 determines that the second switching element 2 is not turned on, it is not in the on period of the second switching element 2, so the process proceeds to step S106, and the first switching element 1 (drive signal) After turning off (0) S_sw1), the process ends.
  • the control device 4 determines that the second switching element 2 is turned on, it is in the on period of the second switching element, so the process proceeds to step S102.
  • step S102 the control device 4 determines whether or not the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH.
  • the control device 4 determines that the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH.
  • the control device 4 proceeds to step S103.
  • step S103 the control device 4 ends the process after setting the first switching element 1 (drive signal S_sw1) to ON (1).
  • the control device 4 determines that the detected value of the secondary current I2 is not larger than the upper limit threshold value I2_thH, the control device 4 proceeds to step S104.
  • step S104 the control device 4 determines whether or not the detected value of the secondary current I2 is smaller than the lower limit threshold value I2_thL.
  • the process proceeds to step S105, and the first switching element 1 (drive signal S_sw1) is turned off (0).
  • the control device 4 ends the process.
  • Control behavior will be described with reference to the time chart shown in FIG. In FIG. 4, the secondary current I2 is shown as an absolute value.
  • the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off (0) to on (1) at the energization start timing, and the first primary winding 3a Is energized and a primary current I1 is passed to store magnetic energy in the iron core.
  • the control device 4 switches the drive signal S_sw1 from on to off to cut off the energization of the first primary winding 3a, and the secondary winding 3c becomes negative.
  • a high secondary voltage is generated, applied to the first electrode 5A of the spark plug 5, the potential drops sharply, and the insulation breakdown voltage is reached, the first electrode 5A and the second electrode of the spark plug 5 are reached.
  • a spark discharge occurs between the gap with 5B.
  • the spark discharge starts, the secondary voltage increases from the breakdown voltage to the discharge maintenance voltage.
  • the secondary current I2 (absolute value) increases stepwise from zero, and then gradually decreases as the magnetic energy stored in the iron core decreases.
  • the detection value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 changed the drive signal S_sw2 to the second switching element 2 from off (0) to on (1). It is switched and the second primary winding 3b is energized.
  • the second primary current I12 flowing through the second primary winding 3b gradually increases, and the energizing magnetic flux generated by the second primary winding 3b gradually increases accordingly. Since the energizing magnetic flux of the second primary winding 3b is a magnetic flux in the same direction as the magnetic flux generated in the iron core, the magnetic energy additionally supplied to the secondary winding 3c via the iron core gradually increases, and 2 The next current I2 also gradually increases.
  • the detected value of the secondary current I2 became larger than the upper limit threshold value I2_thH, so that the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off to on, and the first 1 The next winding 3a is energized.
  • the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off to on, and the first 1 The next winding 3a is energized.
  • the first switching element 1 By making the first switching element 1 conductive, the current additionally supplied to the secondary winding 3c and a part of the magnetic energy stored in the iron core flow to the first primary winding 3a. Therefore, the secondary current I2 decreases.
  • the control device 4 causes the current to flow through the first switching element 1 without interrupting the current flowing through the second switching element 2, a counter electromotive force is applied to the second primary winding 3b.
  • the detected value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 switches the drive signal S_sw1 to the first switching element 1 from on to off, and the first 1 The energization of the next winding 3a is cut off. Since no current flows through the first primary winding 3a, the current supplied from the second primary winding 3b flows through the secondary winding 3c, and the secondary current I2 gradually increases again.
  • the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH, so that the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off to on, and the first The primary winding 3a of the above is energized.
  • the secondary current I2 gradually decreased, and at time t7, the detected value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 sent a drive signal to the first switching element 1.
  • S_sw1 is switched from on to off, and the energization of the first primary winding 3a is cut off.
  • the control device 4 has turned off the second switching element 2, so that the drive signal S_sw2 to the second switching element 2 is switched from on to off, and the first switching element 1 The on / off control is stopped and the first switching element 1 is left off.
  • the secondary current I2 is set to the upper limit threshold value I2_thH and the lower limit by turning on and off the first switching element 1 according to the detected value of the secondary current I2. It can be accurately maintained within the range of the threshold value I2_thL, and the improvement of ignitability and the suppression of the increase in electrode wear can be achieved in a well-balanced manner.
  • control device 4 In the above-described embodiment, the case where the control device 4 always turns on / off the first switching element 1 according to the detected value of the secondary current I2 has been described as an example. However, the control device 4 does not always need to be controlled by using the detected value of the secondary current I2. For example, the control device 4 determines the operation in one ignition cycle in advance and in the next ignition cycle. May turn on / off the first switching element 1 according to a predetermined operation regardless of the detected value of the secondary current I2.
  • the control device 4 may change the upper limit threshold value I2_thH and the lower limit threshold value I2_thL during one control period. For example, in the latter half of the discharge period, the pressure in the cylinder becomes high, and it tends to be difficult to maintain or ignite the discharge.
  • the control device 4 may be configured to increase the lower limit threshold I2_thL as the elapsed time after the start of the spark discharge increases during one discharge period. According to this configuration, good ignition performance can be maintained even in the latter half of the discharge period.
  • FIG. 5 is an electric circuit diagram showing a basic configuration of the ignition device 10 according to the second embodiment.
  • the ignition device 10 is not provided with the secondary current detection circuit 7, but is provided with the power supply voltage detection circuit 8, and accordingly, the first switching element in the control device 4 is turned on and off. The control process is different from the first embodiment.
  • the power supply voltage detection circuit 8 is a circuit for detecting the power supply voltage of the DC power supply 6.
  • the power supply voltage detection circuit 8 is composed of, for example, a voltage dividing resistor circuit, and outputs a voltage corresponding to the output voltage of the DC power supply 6.
  • the power supply voltage detection circuit 8 may be an electric wire that inputs the output voltage of the DC power supply 6 to the control device 4.
  • any circuit may be used as long as it can detect the power supply voltage of the DC power supply 6.
  • the control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the control parameters of the first switching element 1 and the second switching element 2 is set in advance, and is currently present.
  • the control parameters corresponding to the operating state of the internal combustion engine are calculated, and based on the calculated control parameters, the second switching element 2 is turned on during the spark discharge period, and the second switching element 2 is turned on during the on period.
  • the first switching element 1 is turned on and off.
  • the secondary current detection circuit 7 it is not necessary to provide the secondary current detection circuit 7, and the secondary current I2 can be appropriately controlled according to the operating state, and the improvement of ignitability and the suppression of the increase in electrode wear are well balanced. Can be achieved.
  • the control parameter of the first switching element is on / off planning data in which the relationship between the elapsed time and the on time and the on time is set in advance as shown in FIG.
  • the control device 4 turns on / off the first switching element 1 according to the elapsed time after the second switching element 2 is turned on.
  • the on / off planning data may be set in advance by a preliminary test so that the behavior of the secondary current I2 as in the first embodiment is obtained.
  • the control device 4 turns off (0) the first switching element 1 when the elapsed time after the second switching element 2 is turned on is 0, and the second switching element 2
  • the first switching element 1 is turned on (1)
  • the first switching element 1 is turned off (0)
  • the time T3 the first switching element 1 is turned on (1).
  • the control parameters of the first switching element are the on / off frequency and the on-duty of the pulse width modulation control (PWM), and the control device 4 is set during the on period of the second switching element 2.
  • the first switching element 1 may be turned on / off by pulse width modulation control according to the on / off frequency and on duty. As shown in FIG. 7, which will be described later, in the present embodiment, the pulse width modulation control is started from the off period.
  • the control parameter of the first switching element is switched according to the operating state of the internal combustion engine. For example, as the rotation speed of the internal combustion engine increases, the one ignition control period becomes shorter. Therefore, for example, the control parameters may be changed so that the on / off frequency becomes higher. Further, in a high-voltage environment and a strong flow environment, the energy required to maintain the discharge becomes large, so the control parameters may be adjusted so that the secondary current becomes large as a whole.
  • control parameter of the second switching element is data in which the on-time and the on-time after the start of discharge are set.
  • the control device 4 turns on the second switching element 2 when the elapsed time after the start of discharge is on, and turns on the second switching element 2 when the elapsed time after the start of discharge is off. Turn off.
  • the on-time and on-time data may be set in advance by a preliminary test so that the behavior of the secondary current I2 as in the first embodiment is obtained.
  • the control parameter of the second switching element is switched according to the operating state of the internal combustion engine. For example, as the rotation speed of the internal combustion engine increases, the one ignition control period becomes shorter. Therefore, for example, the control parameters may be changed so that the on period of the second switching element becomes shorter. .. Further, in a high-voltage environment and a strong flow environment, the energy required for maintaining the discharge becomes large, so that the on-time may be advanced so that the secondary current becomes large as a whole.
  • the operating conditions of the internal combustion engine are the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the internal combustion engine.
  • the compression ratio of the internal combustion engine is added when the internal combustion engine is provided with a mechanism capable of changing the compression ratio of the internal combustion engine.
  • the operating state of the internal combustion engine is the filling efficiency of the internal combustion engine, the rotation speed of the internal combustion engine, and the exhaust gas recirculation rate.
  • FIG. 7 shows the behavior of the secondary current I2 when the power supply voltage V1 is normal (graph on the left), when it is larger than normal (graph in the center), and when it is smaller than normal (graph on the right).
  • the secondary current I2 is shown as an absolute value.
  • the first switching element 1 and the second switching element 2 are appropriately controlled as will be described later.
  • the on-period of the first first switching element for generating a spark discharge does not change when the power supply voltage V1 is normal, large, or small. Therefore, the magnetic energy stored in the iron core during the on period changes in proportion to the power supply voltage V1, and the initial value of the secondary current I2 after the start of discharge changes. Therefore, the period from the start of discharge until the secondary current I2 reaches the lower limit threshold value I2_thL changes in proportion to the power supply voltage V1. Further, the rate of increase of the secondary current I2 due to the on of the second switching element changes in proportion to the power supply voltage V1. Further, the rate of decrease of the secondary current I2 due to the on of the first switching element changes in proportion to the power supply voltage V1.
  • the on / off frequency of the first switching element for controlling the secondary current I2 within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL changes in proportion to the power supply voltage V1.
  • the control device 4 actually performs control using these. Absent.
  • control device 4 changes the control parameters of the first switching element 1 and the second switching element 2 based on the detected value of the power supply voltage V1, and the spark discharge period based on the changed control parameters.
  • the second switching element 2 is turned on, and the first switching element 1 is turned on and off during the on period of the second switching element.
  • the on timing of the second switching element 2 after the start of discharge is accelerated. Further, as the detected value of the power supply voltage V1 increases, the on / off frequency of the first switching element during the on period of the second switching element is increased.
  • the control device 4 refers to the control setting data in which the relationship between the power supply voltage V1 and the operating state of the internal combustion engine and the control parameters of the first switching element 1 and the second switching element 2 is preset, and is currently used.
  • the control parameters corresponding to the detected value of the power supply voltage V1 and the operating state of the internal combustion engine are calculated, and based on the calculated control parameters, the second switching element 2 is turned on during the spark discharge period, and the second switching element 2 is turned on.
  • the first switching element 1 is turned on and off during the on period of the switching element 2.
  • the power supply voltage V1 may always be included in the operating state of the internal combustion engine.
  • Control behavior> The example shown in FIG. 7 is an example in which the control parameter of the first switching element is the on / off planning data as shown in FIG.
  • On / off plan data is preset for each operating state of the internal combustion engine and for each power supply voltage V1 by a preliminary test or the like so that the secondary current I2 oscillates between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
  • the control device 4 the elapsed time after the start of discharge has reached the on time of the second switching element determined based on the operating state of the internal combustion engine and the detected value of the power supply voltage V1.
  • the second switching element (S_sw2) is turned on (1).
  • the control device 4 reaches the first on time (time t14, t24, t34). ), The first switching element (S_sw1) is turned on (1).
  • the control device 4 reaches when the elapsed time after turning on the second switching element reaches the first off time determined based on the operating state and the detected value of the power supply voltage V1 (time t15, t25, t35). ), The first switching element is turned off (0). After that, similarly, the control device 4 turns on or off the first switching element every time the elapsed time after turning on the second switching element reaches the second on or off time. Then, the control device 4 reaches when the elapsed time after the start of discharge reaches the off time of the second switching element determined based on the operating state and the detected value of the power supply voltage V1 (time t16, t26, t36). The second switching element is turned off (0) and the first switching element is turned off (0).
  • the ignition device 10 according to the third embodiment will be described. The description of the same components as in the first embodiment will be omitted.
  • the basic configuration and processing of the ignition device 10 according to the present embodiment are the same as those of the first embodiment.
  • the on / off control process of the first switching element in the control device 4 is different from that in the first embodiment.
  • the control device 4 turns on / off the first switching element 1 by pulse width modulation control (PWM: Pulse Width Modulation) during the on period of the second switching element 2.
  • PWM Pulse Width Modulation
  • the first switching element 1 can be systematically turned on and off without being affected by the detection delay of the secondary current I2 or the like.
  • the control device 4 starts the pulse width modulation control when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH during the ON period of the second switching element. Pulse width modulation control starts from the on period. According to this configuration, by starting the pulse width modulation control, it is possible to prevent the secondary current I2 from becoming larger than the upper limit threshold value I2_thH.
  • the control device 4 changes the on-duty of the pulse width modulation control so that the detected value of the secondary current I2 falls within the target range.
  • the secondary current I2 can be accurately contained within the target range while taking advantage of the pulse width modulation control that is not easily affected by the detection delay of the secondary current I2. Therefore, by setting the target range, it is possible to improve the ignitability and suppress the increase in electrode wear in a well-balanced manner.
  • the initial value of the on-duty of each ignition cycle may be set based on one or both of the operating state of the internal combustion engine and the power supply voltage V1 as in the second embodiment. Alternatively, it may be set to the final value of on-duty in the previous ignition cycle. In this case, the on-duty in the first ignition cycle may be set to about 0.5.
  • the on-duty is changed according to the feed forward value set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1 and the detected value of the secondary current I2 as in the second embodiment. It may be the total value with the feedback value, and the feedback value may be carried over to the next ignition cycle, or may be reset at each ignition cycle.
  • the on / off frequency of the pulse width modulation control is set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1, as in the second embodiment, and is set in the range of, for example, about 1 kHz to 50 kHz.
  • the control device 4 increases the on-duty of the pulse width modulation control when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH. According to this configuration, it is possible to suppress the detection value of the secondary current I2 from exceeding the upper limit threshold value I2_thH, and the suppression of the increase in electrode wear can be managed by the set value of the upper limit threshold value I2_thH.
  • control device 4 reduces the on-duty of the pulse width modulation control when the detected value of the secondary current I2 becomes smaller than the lower limit threshold value I2_thL set below the upper limit threshold value I2_thH. According to this configuration, it is possible to suppress the detection value of the secondary current I2 from falling below the lower limit threshold value I2_thL, and the improvement of the ignitability can be managed by the set value of the lower limit threshold value I2_thL.
  • the upper limit threshold value I2_thH and the lower limit threshold value I2_thL are set based on the operating state as in the first embodiment.
  • the lower limit threshold value I2_thL is set to a value smaller than the upper limit threshold value I2_thH, but may be set to the same value as the upper limit threshold value I2_thH.
  • the control device 4 is based on the deviation between the upper limit threshold value I2_thH (or the lower limit threshold value I2_thL) and the detected value of the secondary current I2.
  • the on-duty of the pulse width modulation control may be changed by feedback control such as integral control or proportional integral control.
  • the on / off control process according to the present embodiment can be configured as shown in the flowchart shown in FIG.
  • the control device 4 repeatedly executes the process of the flowchart of FIG. 8 for each calculation cycle.
  • step S201 the control device 4 determines whether or not the second switching element 2 (drive signal S_sw2) is turned on (1).
  • the control device 4 determines that the second switching element 2 is not turned on, it is not during the on period of the second switching element 2, so the process proceeds to step S205, and the execution determination information S_PWM of the pulse width modulation control is performed.
  • step S206 the first switching element 1 (drive signal S_sw1) is turned off (0), the execution of pulse width modulation control is stopped, and the process is terminated.
  • step S201 the control device 4 determines in step S201 that the second switching element 2 is turned on, the control device 4 proceeds to step S202.
  • step S202 the control device 4 determines whether or not the execution determination information S_PWM of the pulse width modulation control is set to ON (1). If the control device 4 determines that the execution determination information S_PWM of the pulse width modulation control is not turned on (1), the process proceeds to step S203, and whether or not the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH. To judge. When the control device 4 determines that the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH, the process proceeds to step S204, the execution determination information S_PWM of the pulse width modulation control is set to ON (1), and the pulse width modulation is performed. Start control. The control device 4 starts from the on period when the pulse width modulation control is started.
  • step S202 when the control device 4 determines in step S202 that the execution determination information S_PWM of the pulse width modulation control is turned on (1), the process proceeds to step S207, and the detected value of the secondary current I2 is the upper limit threshold value I2_thH. Determine if it is greater than.
  • step S207 the control device 4 determines in step S207 that the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH, the control device 4 proceeds to step S208, increases the on-duty duty by the change width ⁇ duty, and then ends the process. To do. The increased on-duty duty is reflected in the pulse width modulation control in progress.
  • the change width ⁇ duty is set in consideration of the calculation cycle, the discharge period, and the control response, and is set to, for example, about 0.05.
  • the smaller the change width ⁇ duty the finer the current value can be adjusted, but the control response becomes slower, and the larger the change width ⁇ duty, the faster the control response, but it becomes difficult to finely adjust the current value.
  • step S207 determines in step S207 that the detected value of the secondary current I2 is not larger than the upper limit threshold value I2_thH
  • step S209 the detected value of the secondary current I2 is smaller than the lower limit threshold value I2_thL.
  • the control device 4 proceeds to step S210, reduces the on-duty duty by the change width ⁇ duty, and then ends the process. To do. The reduced on-duty duty is reflected in the pulse width modulation control in progress.
  • step S209 determines in step S209 that the detected value of the secondary current I2 is not smaller than the lower limit threshold value I2_thL
  • the control device 4 ends the process without changing the on-duty duty.
  • Control behavior will be described with reference to the time chart shown in FIG. In FIG. 9, the secondary current I2 is shown as an absolute value. Since the time t51 to the time t52 in FIG. 9 is the same as the time t1 to the time t2 in FIG. 4, the description thereof will be omitted.
  • the secondary current I2 increases stepwise from zero, and then gradually decreases as the magnetic energy stored in the iron core decreases.
  • the detection value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 changed the drive signal S_sw2 to the second switching element 2 from off (0) to on (1). It is switched and the second primary winding 3b is energized. After the start of energization, the secondary current I2 gradually increases.
  • the control device 4 turned on the execution determination information S_PWM of the pulse width modulation control (1) and started the pulse width modulation control. ing. Since the control device 4 starts from the on period at the start of the pulse width modulation control, the drive signal S_sw1 to the first switching element 1 is turned on (1) at time t54. After that, until the time t55, the secondary current I2 is within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL, so that the on-duty duty is not changed, but the average value of the secondary current I2 gradually decreases. ing.
  • the control device 4 reduces the on-duty duty by the change width ⁇ duty. Due to the decrease in on-duty duty, the average value of the secondary current I2 is gradually increasing. Then, at time t56, the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH, so that the control device 4 increases the on-duty duty by the change width ⁇ duty. Then, at time t57, the control device 4 has turned off the second switching element 2, so that the second switching element 2 is switched from on to off, and the execution determination information S_PWM of the pulse width modulation control is displayed. It is turned off (0), the pulse width modulation control is stopped, and the first switching element 1 is turned off.
  • the on-duty of the pulse width modulation control of the first switching element 1 is changed according to the detected value of the secondary current I2, so that the secondary current I2 can be accurately maintained within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL, and improvement of ignitability and suppression of increase in electrode wear can be achieved in a well-balanced manner.
  • control device 4 In the third embodiment, the case where the control device 4 always changes the on-duty of the pulse width modulation control according to the detected value of the secondary current I2 has been described as an example. However, the control device 4 does not always need to be controlled by using the detected value of the secondary current I2. For example, the control device 4 determines the operation in one ignition cycle in advance and in the next ignition cycle. May turn on / off the first switching element 1 according to a predetermined operation regardless of the detected value of the secondary current I2.
  • Embodiment 4 Next, the ignition device 10 according to the fourth embodiment will be described. The description of the same components as in the first embodiment will be omitted.
  • the basic configuration and processing of the ignition device 10 according to the present embodiment are the same as those of the first embodiment.
  • the on / off control process of the first switching element in the control device 4 is different from that in the first embodiment.
  • control device 4 turns on / off the first switching element 1 by pulse width modulation control (PWM: Pulse Width Modulation) during the on period of the second switching element 2.
  • PWM Pulse Width Modulation
  • the control device 4 starts the pulse width modulation control when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH during the ON period of the second switching element. Pulse width modulation control starts from the on period.
  • the control device 4 changes the on / off frequency fpwm of the pulse width modulation control so that the detected value of the secondary current I2 falls within the target range.
  • the amplitude of the secondary current I2 can be decreased by increasing the on / off frequency fpwm, and the amplitude of the secondary current I2 can be increased by decreasing the on / off frequency fpww. Therefore, the vibration range of the secondary current I2 can be changed so that the detected value of the secondary current I2 falls within the target range, and by setting the target range, improvement of ignitability and suppression of increase in electrode wear are balanced. Can be achieved well.
  • the control device 4 increases the on / off frequency fpwm of the pulse width modulation control when the amplitude ⁇ I2 of the detected value of the secondary current I2 becomes larger than the target amplitude ⁇ I2_th.
  • the amplitude ⁇ I2 of the secondary current I2 can be prevented from becoming larger than the target amplitude ⁇ I2_th, and by setting the target amplitude ⁇ I2_th, improvement of ignitability and suppression of increase in electrode wear can be achieved in a well-balanced manner. it can.
  • control device 4 reduces the on / off frequency fpwm of the pulse width modulation control when the amplitude ⁇ I2 of the detected value of the secondary current becomes smaller than the target amplitude ⁇ I2_th. According to this configuration, the amplitude ⁇ I2 of the secondary current I2 can be prevented from becoming smaller than the target amplitude ⁇ I2_th, and the improvement of ignitability and the suppression of the increase in electrode wear can be appropriately balanced.
  • the control device 4 determines the maximum value and the minimum value of the detected value of the secondary current I2 within one cycle of the on / off frequency fpwm, and calculates the amplitude ⁇ I2 from the deviation between the maximum value and the minimum value.
  • the control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the target amplitude ⁇ I2_th is set in advance, and calculates the target amplitude ⁇ I2_th corresponding to the current operating state of the internal combustion engine.
  • the operating state of the internal combustion engine the above-mentioned type of operating state is used.
  • the target amplitude ⁇ I2_th set in advance by a preliminary test or the like is stored in the storage device 91 and read out.
  • the control device 4 may learn the target amplitude ⁇ I2_th by machine learning or the like and use the learned value.
  • the initial value of the on / off frequency fpwm of each ignition cycle may be set based on one or both of the operating state of the internal combustion engine and the power supply voltage V1 as in the second embodiment. Alternatively, it may be set to the final value of the on / off frequency fpwm in the previous ignition cycle. In this case, the on / off frequency fpwm in the first ignition cycle may be set within the range of about 1 kHz to 50 kHz.
  • the on / off frequency fpwm changes according to the feed forward value set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1 and the detected value of the secondary current I2 as in the second embodiment. It may be the total value with the feedback value to be made, and the feedback value may be taken over in the next ignition cycle, or may be reset at each ignition cycle.
  • the on-duty of the pulse width modulation control is set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1, as in the second embodiment.
  • the on-duty may be changed according to the detected value of the secondary current I2 as in the third embodiment.
  • the control device 4 changes the on / off frequency fpwm of the pulse width modulation control by feedback control such as integral control or proportional integral control based on the deviation between the target amplitude ⁇ I2_th and the amplitude ⁇ I2 of the detected value of the secondary current I2. You may let me.
  • the on / off control process according to the present embodiment can be configured as shown in the flowchart shown in FIG.
  • the control device 4 repeatedly executes the process of the flowchart of FIG. 10 for each calculation cycle.
  • steps S301 to S306 of FIG. 10 are the same as steps S201 to S206 of FIG. 8 of the third embodiment, description thereof will be omitted.
  • step S302 When the control device 4 determines in step S302 that the execution determination information S_PWM of the pulse width modulation control is turned on (1), the process proceeds to step S307, and the amplitude ⁇ I2 of the detected value of the secondary current I2 is the target amplitude. It is determined whether or not it is larger than ⁇ I2_th.
  • the target amplitude ⁇ I2_th may be set by the deviation between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
  • step S307 If the control device 4 determines in step S307 that the amplitude ⁇ I2 of the detected value of the secondary current I2 is larger than the target amplitude ⁇ I2_th, the controller 4 proceeds to step S308, increases the on / off frequency fpww by the frequency change width ⁇ f, and then increases the on / off frequency fpwm by the frequency change width ⁇ f. , End the process.
  • the increased on / off frequency fpwm is reflected in the pulse width modulation control during execution.
  • the frequency change width ⁇ f is set in consideration of the calculation cycle, the discharge period, and the control response, and is set to, for example, about 1 kHz. The smaller the frequency change width ⁇ f, the finer the current value can be adjusted, but the control response becomes slower, and the larger the frequency change width ⁇ f, the faster the control response, but it becomes difficult to finely adjust the current value.
  • step S307 determines in step S307 that the amplitude ⁇ I2 of the detected value of the secondary current I2 is not larger than the target amplitude ⁇ I2_th
  • the control device 4 proceeds to step S309 and reduces the on / off frequency fpwm by the frequency change width ⁇ f. After that, the process ends.
  • the reduced on / off frequency fpwm is reflected in the pulse width modulation control during execution.
  • the processing of the flowchart of FIG. 8 may be performed.
  • the processing of steps S307 to S309 of FIG. 10 may be performed.
  • Control behavior will be described with reference to the time chart shown in FIG. In FIG. 11, the secondary current I2 is shown as an absolute value. Since the time t61 to the time t62 in FIG. 11 is the same as the time t1 to the time t2 in FIG. 4, the description thereof will be omitted.
  • the secondary current I2 (absolute value) increases stepwise from zero, and then gradually decreases as the magnetic energy stored in the iron core decreases.
  • the detection value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 changed the drive signal S_sw2 to the second switching element 2 from off (0) to on (1). It is switched and the second primary winding 3b is energized. After the start of energization, the secondary current I2 gradually increases.
  • the control device 4 turned on the execution determination information S_PWM of the pulse width modulation control (1) and started the pulse width modulation control. ing. Since the control device 4 starts from the on period at the start of the pulse width modulation control, the drive signal S_sw1 to the first switching element 1 is turned on (1) at time t64. After the first switching element 1 is turned on, the secondary current I2 decreases.
  • the control device 4 determines the detected value of the secondary current I2 based on the deviation between the maximum value of the secondary current I2 detected at time t64 and the minimum value of the secondary current I2 detected at time t65.
  • the amplitude ⁇ I2 is calculated, and since the amplitude ⁇ I2 is larger than the target amplitude ⁇ I2_th, the on / off frequency fpwm is increased.
  • the target amplitude ⁇ I2_th is set to the deviation between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
  • the amplitude ⁇ I2 of the detected value of the secondary current I2 is larger than the target amplitude ⁇ I2_th, so the on / off frequency fpwm is gradually increased.
  • the amplitude ⁇ I2 of the detected value of the secondary current I2 became smaller than the target amplitude ⁇ I2_th, so that the on / off frequency fpwm was decreased, and then the on / off frequency fpwm was repeatedly increased and decreased to be secondary.
  • the amplitude ⁇ I2 of the detected value of the current I2 is maintained near the target amplitude ⁇ I2_th.
  • the control device 4 has turned off the second switching element 2, so that the second switching element 2 is switched from on to off, and the execution determination information S_PWM of the pulse width modulation control is displayed. It is turned off, the pulse width modulation control is stopped, and the first switching element 1 is turned off.
  • the on / off frequency of the pulse width modulation control of the first switching element 1 is changed according to the detected value of the secondary current I2, so that the secondary current I2 can be accurately maintained within the target range, and improvement in ignitability and suppression of increase in electrode wear can be achieved in a well-balanced manner.
  • control device 4 In the third embodiment, the case where the control device 4 always changes the on / off frequency of the pulse width modulation control according to the detected value of the secondary current I2 has been described as an example. However, the control device 4 does not always need to be controlled by using the detected value of the secondary current I2. For example, the control device 4 determines the operation in one ignition cycle in advance and in the next ignition cycle. May turn on / off the first switching element 1 according to a predetermined operation regardless of the detected value of the secondary current I2.

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  • Chemical & Material Sciences (AREA)
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  • General Engineering & Computer Science (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)

Abstract

Provided is an ignition device with which it is possible to appropriately increase secondary current by energizing a second primary winding during a discharge period in such a manner that the secondary current does not increase excessively or fall excessively. In the ignition device (10), after a first switching element (1) is turned ON, the first switching element (1) is turned OFF, generating a spark discharge in a spark plug (5), during the spark discharge the second switching element (2) is turned ON, and while the second switching element (2) is turned ON, the first switching element (1) is turned ON/OFF.

Description

点火装置Ignition system
　本願は、点火装置に関するものである。 The present application relates to an ignition device.
　車両等に搭載される内燃機関の燃費を向上させる手法として、希薄混合気を燃焼させる希薄燃焼方式、燃焼後の排気を燃焼室内に再循環させる排気再循環方式、あるいは燃焼室を高圧縮比にする方式などが開発されている。しかし、いずれの方式も混合気の点火が難しいという課題があり、着火性の向上が要求されている。 As a method to improve the fuel efficiency of the internal combustion engine mounted on a vehicle, a lean combustion method that burns a lean mixture, an exhaust gas recirculation method that recirculates the exhaust after combustion into the combustion chamber, or a high compression ratio in the combustion chamber. A method of doing so has been developed. However, both methods have a problem that it is difficult to ignite the air-fuel mixture, and improvement in ignitability is required.
　そこで、点火装置を構成するトランスの第１の１次巻線の電流を遮断することによってトランスの２次巻線に生じた２次電流に対して、第２の１次巻線に電流を流すことによって加算的に電流を重畳する点火装置が提案されている（例えば特許文献１を参照）。この手法では、トランスの２次巻線に流れる電流が増加することによって、点火プラグの電極間の放電電流が増加され、放電が安定するため、混合気の着火性が向上する。 Therefore, by cutting off the current of the first primary winding of the transformer constituting the ignition device, a current is passed through the second primary winding with respect to the secondary current generated in the secondary winding of the transformer. As a result, an ignition device that additionally superimposes a current has been proposed (see, for example, Patent Document 1). In this method, the discharge current between the electrodes of the spark plug is increased by increasing the current flowing through the secondary winding of the transformer, and the discharge is stabilized, so that the ignitability of the air-fuel mixture is improved.
米国特許９３９９９７９号U.S. Pat. No. 9399979
　上記の手法では、着火性を向上するために、放電期間中にできるだけ長く第２の１次巻線に通電したい。しかし、放電期間中に第２の１次巻線の通電を継続すると、２次電流が増加し続け、放電電流が大きくなり過ぎ、発熱により、電極消耗量が増大してしまう。その結果、点火プラグ寿命の短期化を招き、点火プラグ交換によるランニングコスト増大が生じる。 In the above method, in order to improve the ignitability, it is desired to energize the second primary winding for as long as possible during the discharge period. However, if the energization of the second primary winding is continued during the discharge period, the secondary current continues to increase, the discharge current becomes too large, and the amount of electrode consumption increases due to heat generation. As a result, the life of the spark plug is shortened, and the running cost is increased by replacing the spark plug.
　特許文献１の技術では、放電期間中に第２の１次巻線を高速でオンオフすることにより、２次電流が増加し続けることを防止し、２次電流が大きくなり過ぎることを防止している。 In the technique of Patent Document 1, by turning on and off the second primary winding at high speed during the discharge period, it is possible to prevent the secondary current from continuing to increase and prevent the secondary current from becoming too large. There is.
　しかし、特許文献１の技術では、特許文献１の図３に示されているように、第２の１次巻線を頻繁にオフにすることにより、２次電流が大きくなり過ぎることを抑制している。しかし、第２の１次巻線をオフする度に、第２の１次巻線に逆起電力が発生し、２次電流が急激に電流重畳前のレベルまで減少している。そのため、第２の１次巻線をオフする度に、放電電流の増加による、放電の安定化効果が損なわれ、筒内流動等により放電が途切れる可能性があり、十分な着火性の向上を図れていなかった。 However, in the technique of Patent Document 1, as shown in FIG. 3 of Patent Document 1, by frequently turning off the second primary winding, it is possible to prevent the secondary current from becoming too large. ing. However, every time the second primary winding is turned off, a counter electromotive force is generated in the second primary winding, and the secondary current is rapidly reduced to the level before the current superposition. Therefore, every time the second primary winding is turned off, the effect of stabilizing the discharge is impaired due to the increase in the discharge current, and the discharge may be interrupted due to the in-cylinder flow or the like, so that the ignitability is sufficiently improved. It wasn't planned.
　そこで、放電期間中の第２の１次巻線の通電により、２次電流が増加し過ぎず、減少し過ぎないよう、２次電流を適度に増加させることができる点火装置が望まれる。 Therefore, an ignition device capable of appropriately increasing the secondary current so that the secondary current does not increase or decrease too much by energizing the second primary winding during the discharge period is desired.
　本願に係る点火装置は、
　通電により通電磁束が生じる第１の１次巻線と、通電により前記第１の１次巻線の通電磁束とは逆方向の通電磁束が生じる第２の１次巻線と、前記第１の１次巻線及び前記第２の１次巻線に磁気結合され、点火プラグに放電エネルギを供給する２次巻線と、を有するトランスと、
　直流電源から前記第１の１次巻線への通電をオンオフする第１のスイッチング素子と、
　前記直流電源から前記第２の１次巻線への通電をオンオフする第２のスイッチング素子と、
　前記第１のスイッチング素子をオンした後、前記第１のスイッチング素子をオフして、前記点火プラグに火花放電を発生させ、
　前記火花放電の期間中に前記第２のスイッチング素子をオンし、
　前記第２のスイッチング素子のオン期間中に、前記第１のスイッチング素子をオンオフする制御装置と、を備えたものである。 The ignition device according to the present application is
A first primary winding in which an energizing magnetic flux is generated by energization, a second primary winding in which an energizing magnetic flux is generated in a direction opposite to the energizing magnetic flux of the first primary winding by energization, and the first winding. A transformer having a primary winding and a secondary winding magnetically coupled to the second primary winding to supply discharge energy to the ignition plug.
A first switching element that turns on / off the energization from the DC power supply to the first primary winding, and
A second switching element that turns on / off the energization from the DC power supply to the second primary winding, and
After turning on the first switching element, the first switching element is turned off to generate a spark discharge in the spark plug.
During the period of the spark discharge, the second switching element is turned on,
It is provided with a control device for turning on / off the first switching element during the on period of the second switching element.
　本願に係る点火装置によれば、火花放電中に第２の１次巻線に通電するので、２次巻線に追加の磁気エネルギが供給され、電極間を流れる放電電流（２次電流）が増加する。これにより、火花放電が強化され、混合気の着火性、火花放電の伸長性を強化することができる。また、第２のスイッチング素子のオン期間中に、第１のスイッチング素子をオンすると、第１の１次巻線が、第２の１次巻線の通電磁束とは逆方向の通電磁束を発生し、２次巻線に追加される磁気エネルギが弱められ、２次電流を減少させることができる。また、第２のスイッチング素子をオンにしたままで、第１のスイッチング素子をオンするので、第２の１次巻線には逆起電力が発生せず、２次電流を緩やかに減少させることができる。よって、第２のスイッチング素子のオン期間中に第１のスイッチング素子をオンオフすることにより、２次電流が増加し過ぎず、減少し過ぎないようにでき、２次電流を適度に増加させることができる。よって、着火性を向上させつつ、点火プラグの電極消耗の増加を抑制することができる。 According to the ignition device according to the present application, since the second primary winding is energized during the spark discharge, additional magnetic energy is supplied to the secondary winding, and the discharge current (secondary current) flowing between the electrodes is generated. To increase. As a result, the spark discharge is strengthened, and the ignitability of the air-fuel mixture and the extensibility of the spark discharge can be strengthened. Further, when the first switching element is turned on during the on period of the second switching element, the first primary winding generates an energizing magnetic flux in the direction opposite to the energizing magnetic flux of the second primary winding. However, the magnetic energy added to the secondary winding is weakened, and the secondary current can be reduced. Further, since the first switching element is turned on while the second switching element is turned on, no back electromotive force is generated in the second primary winding, and the secondary current is gradually reduced. Can be done. Therefore, by turning the first switching element on and off during the on period of the second switching element, the secondary current can be prevented from increasing too much and not decreasing too much, and the secondary current can be appropriately increased. it can. Therefore, it is possible to suppress an increase in electrode wear of the spark plug while improving the ignitability.
実施の形態１に係る点火装置の概略回路図である。It is a schematic circuit diagram of the ignition device which concerns on Embodiment 1. FIG. 実施の形態１に係る制御装置のハードウェア構成図である。It is a hardware block diagram of the control device which concerns on Embodiment 1. FIG. 実施の形態１に係る第１のスイッチング素子のオンオフ制御の処理を説明するフローチャートである。It is a flowchart explaining the process of on / off control of the 1st switching element which concerns on Embodiment 1. FIG. 実施の形態１に係る制御挙動を説明するためのタイムチャートである。It is a time chart for demonstrating the control behavior which concerns on Embodiment 1. 実施の形態２に係る制御装置のハードウェア構成図である。It is a hardware block diagram of the control device which concerns on Embodiment 2. FIG. 実施の形態２に係るオンオフ計画データの設定例を示す図である。It is a figure which shows the setting example of the on-off plan data which concerns on Embodiment 2. FIG. 実施の形態２に係る制御挙動を説明するためのタイムチャートである。It is a time chart for demonstrating the control behavior which concerns on Embodiment 2. 実施の形態３に係る第１のスイッチング素子のオンオフ制御の処理を説明するフローチャートである。It is a flowchart explaining the process of on / off control of the 1st switching element which concerns on Embodiment 3. 実施の形態３に係る制御挙動を説明するためのタイムチャートである。It is a time chart for demonstrating the control behavior which concerns on Embodiment 3. 実施の形態４に係る第１のスイッチング素子のオンオフ制御の処理を説明するフローチャートである。It is a flowchart explaining the process of on / off control of the 1st switching element which concerns on Embodiment 4. 実施の形態４に係る制御挙動を説明するためのタイムチャートである。It is a time chart for demonstrating the control behavior which concerns on Embodiment 4.
１．実施の形態１
　実施の形態１に係る点火装置１０について図面を参照して詳細に説明する。図１は、実施の形態１に係る点火装置１０の基本構成を示す電気回路図である。図１に示すように、点火装置１０は、点火プラグ５、トランス３、第１のスイッチング素子１、第２のスイッチング素子２、２次電流検出回路７、及び制御装置４等を備えている。 1. 1. Embodiment 1
The ignition device 10 according to the first embodiment will be described in detail with reference to the drawings. FIG. 1 is an electric circuit diagram showing a basic configuration of the ignition device 10 according to the first embodiment. As shown in FIG. 1, the ignition device 10 includes a spark plug 5, a transformer 3, a first switching element 1, a second switching element 2, a secondary current detection circuit 7, a control device 4, and the like.
１－１．点火装置の基本構成
　点火プラグ５は、ギャップを介して対向する第１電極５Ａと第２電極５Ｂとを有し、燃焼室内の可燃混合気を点火する。点火プラグ５の第１電極５Ａと第２電極５Ｂは、内燃機関の燃焼室内（気筒内）に配置される。第１電極５Ａは、２次巻線３ｃに接続され、第２電極５Ｂはグランドに接続される。 1-1. Basic configuration of ignition device The spark plug 5 has a first electrode 5A and a second electrode 5B facing each other through a gap, and ignites a combustible air-fuel mixture in a combustion chamber. The first electrode 5A and the second electrode 5B of the spark plug 5 are arranged in the combustion chamber (inside the cylinder) of the internal combustion engine. The first electrode 5A is connected to the secondary winding 3c, and the second electrode 5B is connected to the ground.
　トランス３は、通電により通電磁束が生じる第１の１次巻線３ａと、通電により第１の１次巻線３ａの通電磁束とは逆方向の通電磁束が生じる第２の１次巻線３ｂと、第１の１次巻線３ａ及び第２の１次巻線３ｂに磁気結合され、点火プラグ５に放電エネルギを供給する２次巻線３ｃと、を有している。第１の１次巻線３ａ、第２の１次巻線３ｂ、及び２次巻線３ｃは、共通の鉄心に巻装されている。 In the transformer 3, the first primary winding 3a in which the energization magnetic flux is generated by energization and the second primary winding 3b in which the energization magnetic flux in the direction opposite to the energization magnetic flux of the first primary winding 3a is generated by energization. And a secondary winding 3c that is magnetically coupled to the first primary winding 3a and the second primary winding 3b to supply discharge energy to the spark plug 5. The first primary winding 3a, the second primary winding 3b, and the secondary winding 3c are wound around a common iron core.
　第１の１次巻線３ａの一端及び第２の１次巻線３ｂの他端は、同一の直流電源６にされ、第１の１次巻線３ａの他端が、第１のスイッチング素子１を介してグランドに接続され、第２の１次巻線３ｂの一端が、第２のスイッチング素子２を介してグランドに接続されている。２次巻線３ｃの一端は、点火プラグ５の第１電極５Ａに接続され、２次巻線３ｃの他端はグランド側に接続されている。 One end of the first primary winding 3a and the other end of the second primary winding 3b are made of the same DC power supply 6, and the other end of the first primary winding 3a is the first switching element. It is connected to the ground via 1, and one end of the second primary winding 3b is connected to the ground via the second switching element 2. One end of the secondary winding 3c is connected to the first electrode 5A of the spark plug 5, and the other end of the secondary winding 3c is connected to the ground side.
　第１のスイッチング素子１をオンして第１の１次巻線３ａを通電した時に生じる磁束の方向と、第２のスイッチング素子２をオンして第２の１次巻線３ｂを通電した時に生じる磁束の方向とが、互いに逆方向になるように、各巻線が巻線され、直流電源６に接続されている。 The direction of the magnetic flux generated when the first switching element 1 is turned on and the first primary winding 3a is energized, and when the second switching element 2 is turned on and the second primary winding 3b is energized. Each winding is wound and connected to the DC power supply 6 so that the directions of the generated magnetic fluxes are opposite to each other.
　第１の１次巻線３ａと２次巻線３ｃとの巻き数比（＝２次巻線の巻き数／第１の１次巻線の巻き数）は、第１のスイッチング素子１を所定の時間だけオンした後にオフした際に点火プラグ５に生じる電圧が、点火プラグ５の絶縁破壊電圧以上になるように設定されており、例えば、１００程度である。トランス３と第１のスイッチング素子１とは、フライバックコンバータのように構成されているため、巻き数比倍以上の電圧を点火プラグ５に印加できる。第２の１次巻線３ｂと２次巻線３ｃとの巻き数比（＝２次巻線の巻き数／第２の１次巻線の巻き数）は、第２のスイッチング素子２をオンした時に点火プラグ５に生じる電圧が、放電維持電圧以上になるように設定されており、例えば、２００倍から４００倍程度である。 The turns ratio between the first primary winding 3a and the secondary winding 3c (= the number of turns of the secondary winding / the number of turns of the first primary winding) determines the first switching element 1. The voltage generated in the spark plug 5 when it is turned on and then turned off for the above time is set to be equal to or higher than the breakdown voltage of the spark plug 5, and is, for example, about 100. Since the transformer 3 and the first switching element 1 are configured like a flyback converter, a voltage at least twice the number of turns can be applied to the spark plug 5. The turns ratio between the second primary winding 3b and the secondary winding 3c (= the number of turns of the secondary winding / the number of turns of the second primary winding) turns on the second switching element 2. The voltage generated in the spark plug 5 is set to be equal to or higher than the discharge maintenance voltage, and is, for example, about 200 to 400 times.
　したがって、第２の１次巻線３ｂの巻き数は、第１の１次巻線３ａよりも巻き数が少なくなるように構成されており、第２の１次巻線３ｂの巻き数は第１の１次巻線３ａの１／２から１／４となる。よって、第２の１次巻線３ｂの通電磁束よりも、第１の１次巻線３ａの通電磁束の方が強くなっており、第２の１次巻線３ｂの通電中に、第１の１次巻線３ａを通電させることにより、２次電流Ｉ２を減少させることができる。このような構成により、第１のスイッチング素子１の動作により点火プラグ５の電極間に絶縁破壊を発生させることができ、第２のスイッチング素子２の動作により点火プラグ５の電極間における放電維持が可能となる。 Therefore, the number of turns of the second primary winding 3b is configured to be smaller than the number of turns of the first primary winding 3a, and the number of turns of the second primary winding 3b is the second. It becomes 1/2 to 1/4 of the primary winding 3a of 1. Therefore, the energizing magnetic flux of the first primary winding 3a is stronger than the energizing magnetic flux of the second primary winding 3b, and the first is being energized while the second primary winding 3b is energized. The secondary current I2 can be reduced by energizing the primary winding 3a of the above. With such a configuration, the operation of the first switching element 1 can cause dielectric breakdown between the electrodes of the spark plug 5, and the operation of the second switching element 2 can maintain the discharge between the electrodes of the spark plug 5. It will be possible.
　第１のスイッチング素子１は、直流電源６から第１の１次巻線３ａへの通電をオンオフするスイッチング素子である。第１のスイッチング素子１には、制御装置４から出力された駆動信号Ｓ＿ｓｗ１が入力され、駆動信号Ｓ＿ｓｗ１により第１のスイッチング素子１がオンオフされる。 The first switching element 1 is a switching element that turns on / off the energization from the DC power supply 6 to the first primary winding 3a. The drive signal S_sw1 output from the control device 4 is input to the first switching element 1, and the first switching element 1 is turned on and off by the drive signal S_sw1.
　第２のスイッチング素子２は、直流電源６から第２の１次巻線３ｂへの通電をオンオフするスイッチング素子である。第２のスイッチング素子２には、制御装置４から出力された駆動信号Ｓ＿ｓｗ２が入力され、駆動信号Ｓ＿ｓｗ２により第２のスイッチング素子２がオンオフされる。 The second switching element 2 is a switching element that turns on / off the energization from the DC power supply 6 to the second primary winding 3b. The drive signal S_sw2 output from the control device 4 is input to the second switching element 2, and the second switching element 2 is turned on and off by the drive signal S_sw2.
　第１のスイッチング素子１及び第２のスイッチング素子２には、例えば、ＩＧＢＴ（Insulated Gate Bipolar Transistor）、又はＭＯＳＦＥＴ（Metal Oxide Semiconductor Field Effect Transistor）等が用いられる。各スイッチング素子には、ダイオードが逆並列接続されてもよい。 For the first switching element 1 and the second switching element 2, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or the like is used. Diodes may be connected in antiparallel to each switching element.
　第１のスイッチング素子１を所定の時間（例えば、２ｍｓから１０ｍｓ程度）オンしたあとにオフすることによって、点火プラグ５の電極間に絶縁破壊を発生させる。このとき、第１のスイッチング素子１を流れる電流は最大５Ａから２０Ａ程度である。点火プラグ５の電極間に絶縁破壊が生じた後に、第２のスイッチング素子２を所定の時間（例えば、２００ｕｓから３ｍｓ程度）オンすることによって、点火プラグ５の電極間に放電を維持しつつ追加の電流を供給する。このとき、第２のスイッチング素子２を流れる電流は最大１０Ａから５０Ａ程度となる。したがって、第２のスイッチング素子２の電流定格値は、第１のスイッチング素子１の電流定格値よりも大きくすることが望ましい。 By turning on the first switching element 1 for a predetermined time (for example, about 2 ms to 10 ms) and then turning it off, dielectric breakdown occurs between the electrodes of the spark plug 5. At this time, the maximum current flowing through the first switching element 1 is about 5A to 20A. After dielectric breakdown occurs between the electrodes of the spark plug 5, the second switching element 2 is turned on for a predetermined time (for example, about 200 us to 3 ms) to add the electric discharge between the electrodes of the spark plug 5 while maintaining the discharge. Supply the current of. At this time, the maximum current flowing through the second switching element 2 is about 10 A to 50 A. Therefore, it is desirable that the current rated value of the second switching element 2 is larger than the current rated value of the first switching element 1.
　電流定格値の大きいスイッチング素子は、一般的にオン時の抵抗が低い。よって、電流による素子の過剰発熱、及び過渡発熱による素子破壊を抑制することができる。また、一般的にチップサイズの大きい素子ほど電流定格値が大きいため、第２のスイッチング素子２のチップサイズが第１のスイッチング素子１のチップサイズよりも大きければ、同様の効果を得られる。 Switching elements with a large current rating generally have low resistance when turned on. Therefore, it is possible to suppress excessive heat generation of the element due to electric current and element destruction due to transient heat generation. Further, since an element having a larger chip size generally has a larger current rating value, the same effect can be obtained if the chip size of the second switching element 2 is larger than the chip size of the first switching element 1.
　第１のスイッチング素子１は、第２のスイッチング素子２のオン期間中にオンオフされる（スイッチングされる）。よって、第１のスイッチング素子１のスイッチング時間（立ち下がり時間、立ち上がり時間、上昇時間、下降時間）は、第２のスイッチング素子２のスイッチング時間よりも短いことが望ましい。数ｍｓの第２のスイッチング素子２のオン期間中に、第１のスイッチング素子１を高周波でオンオフでき、後述する２次電流のピークを低減する制御を行い易い。また短いスイッチング時間は、スイッチング損失の低減にも寄与する。 The first switching element 1 is turned on / off (switched) during the on period of the second switching element 2. Therefore, it is desirable that the switching time (falling time, rising time, rising time, falling time) of the first switching element 1 is shorter than the switching time of the second switching element 2. During the on period of the second switching element 2 of several ms, the first switching element 1 can be turned on and off at a high frequency, and it is easy to control to reduce the peak of the secondary current described later. The short switching time also contributes to the reduction of switching loss.
　２次電流検出回路７は、点火プラグ５の火花放電中に２次巻線３ｃに流れる２次電流Ｉ２を検出するための回路である。２次電流検出回路７は、２次電流Ｉ２の放電経路上に直列接続された抵抗（以下、２次電流検出抵抗７と称す）である。２次電流検出抵抗７の低電圧側端子は、グランドに接続され、２次電流検出抵抗７の高電圧側端子は、２次巻線３ｃの他端に接続されている。２次電流検出抵抗７の高電圧側端子の電圧が制御装置４に入力される。２次電流検出回路７は、２次電流Ｉ２の放電経路上に配置されたカレントトランス又はホールセンサであってもよい。 The secondary current detection circuit 7 is a circuit for detecting the secondary current I2 flowing in the secondary winding 3c during the spark discharge of the spark plug 5. The secondary current detection circuit 7 is a resistor (hereinafter, referred to as a secondary current detection resistor 7) connected in series on the discharge path of the secondary current I2. The low voltage side terminal of the secondary current detection resistor 7 is connected to the ground, and the high voltage side terminal of the secondary current detection resistor 7 is connected to the other end of the secondary winding 3c. The voltage of the high voltage side terminal of the secondary current detection resistor 7 is input to the control device 4. The secondary current detection circuit 7 may be a current transformer or a Hall sensor arranged on the discharge path of the secondary current I2.
１－２．制御装置
　本実施の形態では、制御装置４は、内燃機関を制御する内燃機関の制御装置とされている。制御装置４の各機能は、制御装置４が備えた処理回路により実現される。具体的には、制御装置４は、図２に示すように、処理回路として、ＣＰＵ（Central Processing Unit）等の演算処理装置９０（コンピュータ）、演算処理装置９０とデータのやり取りをする記憶装置９１、演算処理装置９０に外部の信号を入力する入力回路９２、及び演算処理装置９０から外部に信号を出力する出力回路９３等を備えている。 1-2. Control device In the present embodiment, the control device 4 is a control device for an internal combustion engine that controls an internal combustion engine. Each function of the control device 4 is realized by a processing circuit provided in the control device 4. Specifically, as shown in FIG. 2, the control device 4 is a storage device 91 that exchanges data with an arithmetic processing unit 90 (computer) such as a CPU (Central Processing Unit) and an arithmetic processing unit 90 as a processing circuit. An input circuit 92 for inputting an external signal to the arithmetic processing unit 90, an output circuit 93 for outputting a signal from the arithmetic processing unit 90 to the outside, and the like are provided.
　演算処理装置９０として、ＡＳＩＣ（Application Specific Integrated Circuit）、ＩＣ（Integrated Circuit）、ＤＳＰ（Digital Signal Processor）、ＦＰＧＡ（Field Programmable Gate Array）、各種の論理回路、及び各種の信号処理回路等が備えられてもよい。また、演算処理装置９０として、同じ種類のもの又は異なる種類のものが複数備えられ、各処理が分担して実行されてもよい。記憶装置９１として、演算処理装置９０からデータを読み出し及び書き込みが可能に構成されたＲＡＭ（Random Access Memory）、演算処理装置９０からデータを読み出し可能に構成されたＲＯＭ（Read Only Memory）等が備えられている。入力回路９２は、２次電流検出回路７、及び内燃機関の各種センサ２１（クランク角度センサ、カム角センサ、吸気量検出センサ、圧力センサ、水温センサ、電源電圧センサ等）が接続され、これらの出力信号を演算処理装置９０に入力するＡ／Ｄ変換器等を備えている。出力回路９３は、第１のスイッチング素子１、第２のスイッチング素子２、及び内燃機関の各種の電気負荷２２（インジェクタ、排気再循環バルブ等）が接続され、これらに演算処理装置９０から制御信号を出力する駆動回路等を備えている。第一のスイッチング素子１に接続される駆動回路のローパスフィルタのカットオフ周波数は、１００ｋＨｚ以上に設定されることが望ましい。 The arithmetic processing device 90 includes an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. You may. Further, a plurality of arithmetic processing units 90 of the same type or different types may be provided, and each processing may be shared and executed. The storage device 91 includes a RAM (Random Access Memory) configured to be able to read and write data from the arithmetic processing device 90, a ROM (Read Only Memory) configured to be able to read data from the arithmetic processing device 90, and the like. Has been done. The input circuit 92 is connected to the secondary current detection circuit 7 and various sensors 21 of the internal combustion engine (crank angle sensor, cam angle sensor, intake air amount detection sensor, pressure sensor, water temperature sensor, power supply voltage sensor, etc.). It is equipped with an A / D converter or the like that inputs an output signal to the arithmetic processing device 90. The output circuit 93 is connected to a first switching element 1, a second switching element 2, and various electric loads 22 (injectors, exhaust gas recirculation valves, etc.) of an internal combustion engine, and a control signal is transmitted from the arithmetic processing device 90 to these. It is equipped with a drive circuit that outputs. It is desirable that the cutoff frequency of the low-pass filter of the drive circuit connected to the first switching element 1 is set to 100 kHz or more.
　そして、制御装置４が備える各機能は、演算処理装置９０が、ＲＯＭ等の記憶装置９１に記憶されたソフトウェア（プログラム）を実行し、記憶装置９１、入力回路９２、及び出力回路９３等の制御装置４の他のハードウェアと協働することにより実現される。なお、制御装置４が用いる制御設定データ等の設定データは、ソフトウェア（プログラム）の一部として、ＲＯＭ等の記憶装置９１に記憶されている。以下、制御装置４の各機能について詳細に説明する。 Then, in each function provided in the control device 4, the arithmetic processing unit 90 executes software (program) stored in the storage device 91 such as ROM, and controls the storage device 91, the input circuit 92, the output circuit 93, and the like. It is realized by cooperating with other hardware of the device 4. The setting data such as the control setting data used by the control device 4 is stored in the storage device 91 such as the ROM as a part of the software (program). Hereinafter, each function of the control device 4 will be described in detail.
　制御装置４は、基本的な制御として、入力された各種センサの出力信号等に基づいて、内燃機関の回転速度、充填効率（気筒内の圧力情報）、冷却水温度、排気再循環率等の内燃機関の運転状態を検出し、運転状態に基づいて、点火時期、目標空燃比、燃料噴射量、排気再循環バルブの制御量等を算出し、インジェクタ及び排気再循環バルブ等の内燃機関の各種の電気負荷２２、第１のスイッチング素子１、及び第２のスイッチング素子２等を駆動制御する。 As basic control, the control device 4 determines the rotation speed of the internal combustion engine, filling efficiency (pressure information in the cylinder), cooling water temperature, exhaust gas recirculation rate, etc., based on the output signals of various input sensors. Detects the operating state of the internal combustion engine, calculates the ignition timing, target air-fuel ratio, fuel injection amount, control amount of the exhaust gas recirculation valve, etc. based on the operating state, and various types of internal combustion engines such as injectors and exhaust gas recirculation valves. The electric load 22, the first switching element 1, the second switching element 2, and the like are driven and controlled.
＜点火制御＞
　制御装置４は、第１のスイッチング素子１をオンして第１の１次巻線３ａへの通電をオンさせた後、第１のスイッチング素子１をオフして第１の１次巻線３ａへの通電をオフさせ、点火プラグ５に火花放電を発生させる。 <Ignition control>
The control device 4 turns on the first switching element 1 to turn on the energization of the first primary winding 3a, and then turns off the first switching element 1 to turn on the first primary winding 3a. The power supply to the ignition plug 5 is turned off to generate a spark discharge in the spark plug 5.
　制御装置４は、第１の１次巻線３ａへの通電期間と点火時期（点火クランク角度）を算出する。本実施の形態では、制御装置４は、内燃機関の運転状態に基づいて、通電期間及び点火時期を決定する。内燃機関の運転状態は、内燃機関の充填効率（気筒内の圧力）、内燃機関の回転速度、排気再循環率等とされる。 The control device 4 calculates the energization period and ignition timing (ignition crank angle) of the first primary winding 3a. In the present embodiment, the control device 4 determines the energization period and the ignition timing based on the operating state of the internal combustion engine. The operating state of the internal combustion engine is the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the exhaust gas recirculation rate, and the like.
　制御装置４は、通電期間の間、第１のスイッチング素子１をオンして、第１の１次巻線３ａを通電させた後、点火時期で、第１のスイッチング素子１をオフして、第１の１次巻線３ａへの通電を遮断させ、２次巻線３ｃに高電圧を発生させ、点火プラグ５に火花放電を生じさせる。火花放電は、点火プラグ５の鉄心に蓄積されていた磁気エネルギが減少するまで継続する。 The control device 4 turns on the first switching element 1 during the energization period, energizes the first primary winding 3a, and then turns off the first switching element 1 at the ignition timing. The energization of the first primary winding 3a is cut off, a high voltage is generated in the secondary winding 3c, and a spark discharge is generated in the spark plug 5. The spark discharge continues until the magnetic energy stored in the iron core of the spark plug 5 is reduced.
＜第２の１次巻線の通電制御＞
　制御装置４は、火花放電の期間中に第２のスイッチング素子２をオンにする。火花放電中に第２の１次巻線３ｂに通電すると、２次巻線３ｃに追加の磁気エネルギが供給され、電極間を流れる放電電流（２次電流Ｉ２）が増加する。これにより、火花放電が強化され、混合気の着火性、火花放電の伸長性が強化される。 <Energization control of the second primary winding>
The control device 4 turns on the second switching element 2 during the spark discharge period. When the second primary winding 3b is energized during the spark discharge, additional magnetic energy is supplied to the secondary winding 3c, and the discharge current (secondary current I2) flowing between the electrodes increases. As a result, the spark discharge is strengthened, and the ignitability of the air-fuel mixture and the extensibility of the spark discharge are strengthened.
　放電電流が大きいほど、放電が途切れ難く、維持されやすいという傾向がある。第２の１次巻線３ｂを通電して２次電流Ｉ２（放電電流）を増加させることは、放電を長時間維持することによって混合気を着火する確率を高めることを目的としているため、２次電流Ｉ２を大きくすることは着火性の向上に寄与する。 The larger the discharge current, the more difficult the discharge is to be interrupted and the easier it is to maintain. Since the purpose of energizing the second primary winding 3b to increase the secondary current I2 (discharge current) is to increase the probability of igniting the air-fuel mixture by maintaining the discharge for a long time, 2 Increasing the next current I2 contributes to the improvement of ignitability.
　着火性向上の必要性は、内燃機関の運転状態によって変化するため、第２のスイッチング素子２のオン期間は、内燃機関の運転状態に応じて調整されることが望ましい。そこで、本実施の形態では、制御装置４は、内燃機関の運転状態と、第２のスイッチング素子２のオン時期及びオフ時期の制御パラメータとの関係が予め設定された制御設定データを参照し、現在の内燃機関の運転状態に対応するオン時期及びオフ時期の制御パラメータを算出する。 Since the necessity of improving the ignitability changes depending on the operating state of the internal combustion engine, it is desirable that the on period of the second switching element 2 is adjusted according to the operating state of the internal combustion engine. Therefore, in the present embodiment, the control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the control parameters of the on time and the off time of the second switching element 2 is set in advance. Calculate the on-time and off-time control parameters corresponding to the current operating state of the internal combustion engine.
　本実施の形態では、オン時期の制御パラメータは、２次電流Ｉ２の下限閾値Ｉ２＿ｔｈＬである。下限閾値Ｉ２＿ｔｈＬは、後述する第１のスイッチング素子１をオフする閾値と共通化されている。制御装置４は、放電開始後、２次電流Ｉ２の検出値が、下限閾値Ｉ２＿ｔｈＬよりも小さくなった時に、第２のスイッチング素子２をオンにする。なお、オン時期の制御パラメータは、放電開始後の経過時間とされてもよく、制御装置４は、放電開始後の経過時間が閾値に到達した時に、第２のスイッチング素子２をオンしてもよい。オフ時期の制御パラメータは、放電開始後のオフ時期とされている。制御装置４は、放電開始後の経過時間が、オフ時期になった時に、第２のスイッチング素子２をオフにする。　 In the present embodiment, the control parameter of the ON timing is the lower limit threshold value I2_thL of the secondary current I2. The lower limit threshold value I2_thL is shared with the threshold value for turning off the first switching element 1 described later. The control device 4 turns on the second switching element 2 when the detected value of the secondary current I2 becomes smaller than the lower limit threshold value I2_thL after the start of discharge. The control parameter at the on time may be the elapsed time after the start of discharge, and the control device 4 may turn on the second switching element 2 when the elapsed time after the start of discharge reaches the threshold value. Good. The control parameter for the off time is the off time after the start of discharge. The control device 4 turns off the second switching element 2 when the elapsed time after the start of discharge reaches the off time.
　なお、本願では、２次電流Ｉ２は、２次電流Ｉ２の絶対値を意味するものとする。また、「放電開始後」及び「火花放電の開始後」は、火花放電を発生させるために、第１のスイッチング素子１をオフした後である。 In the present application, the secondary current I2 means the absolute value of the secondary current I2. Further, "after the start of discharge" and "after the start of spark discharge" are after the first switching element 1 is turned off in order to generate spark discharge.
　オン時期及びオフ時期の制御パラメータは、予備試験等により予め設定されたものが、記憶装置９１に格納され、読み出される。或いは、制御装置４は、機械学習等によりオン時期及びオフ時期の制御パラメータを学習し、学習値を用いてもよい。 The control parameters for the on time and the off time, which are preset by a preliminary test or the like, are stored in the storage device 91 and read out. Alternatively, the control device 4 may learn the control parameters of the on-time and the off-time by machine learning or the like, and use the learned values.
　内燃機関の運転状態は、内燃機関の充填効率（気筒内の圧力）、内燃機関の回転速度、内燃機関の圧縮比、空燃比、排気再循環率、内燃機関の始動後の経過時間、及び内燃機関の冷却水温度のいずれか一つ以上である。内燃機関の圧縮比は、内燃機関の圧縮比を変更可能な機構が内燃機関に備えられている場合に加えられる。例えば、内燃機関の運転状態は、内燃機関の充填効率、内燃機関の回転速度、及び排気再循環率とされる。 The operating conditions of the internal combustion engine are the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the internal combustion engine. One or more of the cooling water temperatures of the engine. The compression ratio of the internal combustion engine is added when the internal combustion engine is provided with a mechanism capable of changing the compression ratio of the internal combustion engine. For example, the operating state of the internal combustion engine is the filling efficiency of the internal combustion engine, the rotation speed of the internal combustion engine, and the exhaust gas recirculation rate.
＜第１の１次巻線のオンオフ制御＞
　一方、第２の１次巻線３ｂの通電により２次電流Ｉ２（放電電流）が増加し過ぎると、点火プラグの電極消耗が増加する。これは、放電電流の増加により発生する熱が増加し、電極を構成する金属体の溶融量が増加することが要因となる。従って、２次電流Ｉ２の増加を低くするほど、電極消耗の増加を抑制できる。一方、増加し過ぎた２次電流Ｉ２を減少させるために、第２のスイッチング素子２をオフにすると、第２の１次巻線３ｂに逆起電力が発生し、２次電流Ｉ２が減少し過ぎ、着火性が損なわれる場合がある。そのため、第２の１次巻線３ｂの通電により、２次電流Ｉ２が増加し過ぎず、減少し過ぎないよう、２次電流Ｉ２を適度に増加させることが望まれる。 <On / off control of the first primary winding>
On the other hand, if the secondary current I2 (discharge current) increases too much due to the energization of the second primary winding 3b, the electrode wear of the spark plug increases. This is due to the increase in heat generated by the increase in discharge current and the increase in the amount of melting of the metal body constituting the electrode. Therefore, the lower the increase in the secondary current I2, the more the increase in electrode wear can be suppressed. On the other hand, when the second switching element 2 is turned off in order to reduce the excessively increased secondary current I2, a counter electromotive force is generated in the second primary winding 3b and the secondary current I2 decreases. It may pass and the ignitability may be impaired. Therefore, it is desired to appropriately increase the secondary current I2 so that the secondary current I2 does not increase too much and does not decrease too much by energizing the second primary winding 3b.
　そこで、制御装置４は、第２のスイッチング素子２のオン期間中に、第１のスイッチング素子１をオンオフする。この構成によれば、第２のスイッチング素子２のオン期間中に、第１のスイッチング素子１をオンすると、第１の１次巻線３ａが、第２の１次巻線３ｂの通電磁束とは逆方向の通電磁束を発生し、２次巻線３ｃに追加される磁気エネルギが弱められ、２次電流Ｉ２を低下させることができる。また、第２のスイッチング素子２をオンにしたままで、第１のスイッチング素子１をオンするので、第２の１次巻線３ｂには逆起電力が発生せず、２次電流Ｉ２を緩やかに減少させることができる。よって、第２のスイッチング素子２のオン期間中に第１のスイッチング素子１をオンオフすることにより、２次電流Ｉ２が増加し過ぎず、減少し過ぎないようにでき、２次電流Ｉ２を適度に増加させることができる。よって、着火性を向上させつつ、点火プラグの電極消耗の増加を抑制することができる。 Therefore, the control device 4 turns on / off the first switching element 1 during the on period of the second switching element 2. According to this configuration, when the first switching element 1 is turned on during the on period of the second switching element 2, the first primary winding 3a becomes the energizing magnetic flux of the second primary winding 3b. Generates an energizing magnetic flux in the opposite direction, weakens the magnetic energy added to the secondary winding 3c, and can reduce the secondary current I2. Further, since the first switching element 1 is turned on with the second switching element 2 turned on, no counter electromotive force is generated in the second primary winding 3b, and the secondary current I2 is moderated. Can be reduced to. Therefore, by turning on / off the first switching element 1 during the on period of the second switching element 2, the secondary current I2 can be prevented from increasing too much and not decreasing too much, and the secondary current I2 can be appropriately adjusted. Can be increased. Therefore, it is possible to suppress an increase in electrode wear of the spark plug while improving the ignitability.
＜２次電流に応じたオンオフ制御＞
　本実施の形態では、制御装置４は、２次電流検出回路７の出力信号に基づいて、２次電流Ｉ２を検出する。そして、制御装置４は、第２のスイッチング素子２のオン期間中に、２次電流Ｉ２の検出値に基づいて、第１のスイッチング素子１をオンオフする。この構成によれば、２次電流Ｉ２の検出値に基づいているので、精度良く、２次電流Ｉ２を適度に増加させ、２次電流Ｉ２を増加させ過ぎないようにできる。 <On / off control according to the secondary current>
In the present embodiment, the control device 4 detects the secondary current I2 based on the output signal of the secondary current detection circuit 7. Then, the control device 4 turns on / off the first switching element 1 based on the detected value of the secondary current I2 during the on period of the second switching element 2. According to this configuration, since it is based on the detected value of the secondary current I2, it is possible to increase the secondary current I2 appropriately and not to increase the secondary current I2 too much with high accuracy.
　本例では、制御装置４は、第２のスイッチング素子のオン期間中に、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなった時に、第１のスイッチング素子１をオンし、第１のスイッチング素子１をオンした後、２次電流Ｉ２の検出値が、上限閾値Ｉ２＿ｔｈＨ以下の値に設定された下限閾値Ｉ２＿ｔｈＬよりも小さくなった時に、第１のスイッチング素子１をオフするように構成されている。以下で説明する例では、下限閾値Ｉ２＿ｔｈＬが、上限閾値Ｉ２＿ｔｈＨよりも小さい値に設定されているが、同じ値に設定されてよい。 In this example, the control device 4 turns on the first switching element 1 when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH during the on period of the second switching element, and the first switching element 1 is turned on. When the detected value of the secondary current I2 becomes smaller than the lower limit threshold value I2_thL set to a value equal to or lower than the upper limit threshold value I2_thH after the switching element 1 is turned on, the first switching element 1 is turned off. Has been done. In the example described below, the lower limit threshold value I2_thL is set to a value smaller than the upper limit threshold value I2_thH, but it may be set to the same value.
　この構成によれば、２次電流Ｉ２を、精度良く、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの範囲内に制御できる。上限閾値Ｉ２＿ｔｈＨの設定値により、点火プラグの電極消耗の増加抑制を管理でき、下限閾値Ｉ２＿ｔｈＬの設定値により、着火性の向上を管理できる。 According to this configuration, the secondary current I2 can be accurately controlled within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL. The set value of the upper limit threshold value I2_thH can control the suppression of increase in electrode wear of the spark plug, and the set value of the lower limit threshold value I2_thL can manage the improvement of ignitability.
　着火性の向上及び電極消耗の増加抑制を達成できる、上限閾値Ｉ２＿ｔｈＨの最適な設定値及び下限閾値Ｉ２＿ｔｈＬの最適な設定値は、内燃機関の運転状態によって変化する。例えば、気筒内の流動が大きく、放電が吹き流されて途絶しやすい運転条件であれば、放電電流を大きく維持することが望ましい。しかし、放電電流が過度に大きければ着火性を向上できても電極消耗量が大きくなるため、点火プラグの寿命が短くなる。よって、着火性と電極消耗とはトレードオフの関係にあるため、内燃機関の運転状態に基づいて適切な２次電流（放電電流）の値が決定されることが望ましい。 The optimum set value of the upper limit threshold value I2_thH and the optimum set value of the lower limit threshold value I2_thL, which can improve the ignitability and suppress the increase in electrode wear, change depending on the operating state of the internal combustion engine. For example, it is desirable to maintain a large discharge current under operating conditions in which the flow in the cylinder is large and the discharge is easily blown off. However, if the discharge current is excessively large, the life of the spark plug is shortened because the amount of electrode consumption is large even if the ignitability can be improved. Therefore, since there is a trade-off relationship between ignitability and electrode wear, it is desirable to determine an appropriate secondary current (discharge current) value based on the operating state of the internal combustion engine.
　そこで、制御装置４は、内燃機関の運転状態と、上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬとの関係が予め設定された制御設定データを参照し、現在の内燃機関の運転状態に対応する上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬを算出する。 Therefore, the control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the upper limit threshold value I2_thH and the lower limit threshold value I2_thL is set in advance, and refers to the upper limit threshold value I2_thH and the upper limit threshold value I2_thH corresponding to the current operating state of the internal combustion engine. The lower limit threshold I2_thL is calculated.
　内燃機関の運転状態は、内燃機関の充填効率（気筒内の圧力）、内燃機関の回転速度、内燃機関の圧縮比、空燃比、排気再循環率、内燃機関の始動後の経過時間、及び内燃機関の冷却水温度のいずれか一つ以上である。内燃機関の圧縮比は、内燃機関の圧縮比を変更可能な機構が内燃機関に備えられている場合に加えられる。例えば、内燃機関の運転状態は、内燃機関の充填効率、内燃機関の回転速度、及び排気再循環率とされる。 The operating conditions of the internal combustion engine are the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the internal combustion engine. One or more of the cooling water temperatures of the engine. The compression ratio of the internal combustion engine is added when the internal combustion engine is provided with a mechanism capable of changing the compression ratio of the internal combustion engine. For example, the operating state of the internal combustion engine is the filling efficiency of the internal combustion engine, the rotation speed of the internal combustion engine, and the exhaust gas recirculation rate.
　上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬは、予備試験等により予め設定されたものが、記憶装置９１に格納され、読み出される。或いは、制御装置４は、失火せずに点火が可能であった電流値を判定し、判定した電流値に基づいて、機械学習等により上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬを学習し、学習値を用いてもよい。 The upper limit threshold value I2_thH and the lower limit threshold value I2_thL, which are preset by a preliminary test or the like, are stored in the storage device 91 and read out. Alternatively, the control device 4 determines the current value at which ignition was possible without misfire, learns the upper limit threshold value I2_thH and the lower limit threshold value I2_thL by machine learning or the like based on the determined current value, and uses the learned value. You may.
＜オンオフ制御のフローチャート＞
　このオンオフ制御の処理は、図３に示すフローチャートのように構成できる。制御装置４は、演算周期毎に図３のフローチャートの処理を繰り返し実行する。まず、ステップＳ１０１で、制御装置４は、第２のスイッチング素子２（駆動信号Ｓ＿ｓｗ２）をオン（１）にしているか否かを判定する。制御装置４は、第２のスイッチング素子２がオンにされていないと判定した場合は、第２のスイッチング素子２のオン期間中でないので、ステップＳ１０６に進み、第１のスイッチング素子１（駆動信号Ｓ＿ｓｗ１）をオフ（０）にした後、処理を終了する。一方、制御装置４は、第２のスイッチング素子２がオンにされていると判定した場合は、第２のスイッチング素子のオン期間中であるので、ステップＳ１０２に進む。 <Flowchart of on / off control>
This on / off control process can be configured as shown in the flowchart shown in FIG. The control device 4 repeatedly executes the process of the flowchart of FIG. 3 for each calculation cycle. First, in step S101, the control device 4 determines whether or not the second switching element 2 (drive signal S_sw2) is turned on (1). When the control device 4 determines that the second switching element 2 is not turned on, it is not in the on period of the second switching element 2, so the process proceeds to step S106, and the first switching element 1 (drive signal) After turning off (0) S_sw1), the process ends. On the other hand, when the control device 4 determines that the second switching element 2 is turned on, it is in the on period of the second switching element, so the process proceeds to step S102.
　ステップＳ１０２で、制御装置４は、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きいか否かを判定する。制御装置４は、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きいと判定した場合は、ステップＳ１０３に進む。ステップＳ１０３で、制御装置４は、第１のスイッチング素子１（駆動信号Ｓ＿ｓｗ１）をオン（１）に設定した後、処理を終了する。一方、制御装置４は、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくないと判定した場合は、ステップＳ１０４に進む。 In step S102, the control device 4 determines whether or not the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH. When the control device 4 determines that the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH, the control device 4 proceeds to step S103. In step S103, the control device 4 ends the process after setting the first switching element 1 (drive signal S_sw1) to ON (1). On the other hand, when the control device 4 determines that the detected value of the secondary current I2 is not larger than the upper limit threshold value I2_thH, the control device 4 proceeds to step S104.
　ステップＳ１０４で、制御装置４は、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さいか否かを判定する。制御装置４は、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さいと判定した場合は、ステップＳ１０５に進み、第１のスイッチング素子１（駆動信号Ｓ＿ｓｗ１）をオフ（０）にする。一方、制御装置４は、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さくないと判定した場合は、処理を終了する。 In step S104, the control device 4 determines whether or not the detected value of the secondary current I2 is smaller than the lower limit threshold value I2_thL. When the control device 4 determines that the detected value of the secondary current I2 is smaller than the lower limit threshold value I2_thL, the process proceeds to step S105, and the first switching element 1 (drive signal S_sw1) is turned off (0). On the other hand, when the control device 4 determines that the detected value of the secondary current I2 is not smaller than the lower limit threshold value I2_thL, the control device 4 ends the process.
＜制御挙動＞
　図４に示すタイムチャートを用いて、制御挙動を説明する。図４において、２次電流Ｉ２は、絶対値で示されている。図４の時刻ｔ１において、制御装置４は、通電開始タイミングで、第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１を、オフ（０）からオン（１）に切り替え、第１の１次巻線３ａに通電し、１次電流Ｉ１を流し、鉄心に磁気エネルギを蓄積させる。 <Control behavior>
The control behavior will be described with reference to the time chart shown in FIG. In FIG. 4, the secondary current I2 is shown as an absolute value. At the time t1 of FIG. 4, the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off (0) to on (1) at the energization start timing, and the first primary winding 3a Is energized and a primary current I1 is passed to store magnetic energy in the iron core.
　その後、制御装置４は、通電期間が経過した時刻ｔ２において、駆動信号Ｓ＿ｓｗ１を、オンからオフに切り替えて、第１の１次巻線３ａの通電を遮断すると、２次巻線３ｃに負の高電圧の２次電圧が発生し、点火プラグ５の第１電極５Ａに印加されて、その電位が急峻に低下し、絶縁破壊電圧に至ると、点火プラグ５の第１電極５Ａと第２電極５Ｂとのギャップ間に火花放電が発生する。火花放電が開始すると、２次電圧は、絶縁破壊電圧から増加し、放電維持電圧になる。 After that, at the time t2 when the energization period elapses, the control device 4 switches the drive signal S_sw1 from on to off to cut off the energization of the first primary winding 3a, and the secondary winding 3c becomes negative. When a high secondary voltage is generated, applied to the first electrode 5A of the spark plug 5, the potential drops sharply, and the insulation breakdown voltage is reached, the first electrode 5A and the second electrode of the spark plug 5 are reached. A spark discharge occurs between the gap with 5B. When the spark discharge starts, the secondary voltage increases from the breakdown voltage to the discharge maintenance voltage.
　時刻ｔ２で、火花放電が開始すると、２次電流Ｉ２（絶対値）がステップ的にゼロから増加した後、鉄心に蓄積されていた磁気エネルギが減少するに従って、次第に減少していく。 When the spark discharge starts at time t2, the secondary current I2 (absolute value) increases stepwise from zero, and then gradually decreases as the magnetic energy stored in the iron core decreases.
　時刻ｔ３で、制御装置４は、２次電流Ｉ２の検出値が、下限閾値Ｉ２＿ｔｈＬより小さくなったので、第２のスイッチング素子２への駆動信号Ｓ＿ｓｗ２を、オフ（０）からオン（１）に切り替え、第２の１次巻線３ｂに通電する。通電開始後、第２の１次巻線３ｂに流れる第２の１次電流Ｉ１２が次第に増加していき、それに応じて、第２の１次巻線３ｂが発生する通電磁束が次第に増加する。第２の１次巻線３ｂの通電磁束は、鉄心に生じている磁束と同じ方向の磁束であるので、鉄心を介して２次巻線３ｃに追加供給される磁気エネルギが次第に増加し、２次電流Ｉ２も次第に増加していく。 At time t3, the detection value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 changed the drive signal S_sw2 to the second switching element 2 from off (0) to on (1). It is switched and the second primary winding 3b is energized. After the start of energization, the second primary current I12 flowing through the second primary winding 3b gradually increases, and the energizing magnetic flux generated by the second primary winding 3b gradually increases accordingly. Since the energizing magnetic flux of the second primary winding 3b is a magnetic flux in the same direction as the magnetic flux generated in the iron core, the magnetic energy additionally supplied to the secondary winding 3c via the iron core gradually increases, and 2 The next current I2 also gradually increases.
　時刻ｔ４で、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなったので、制御装置４は、第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１を、オフからオンに切り替え、第１の１次巻線３ａに通電する。第１のスイッチング素子１を導通させることにより、２次巻線３ｃに追加供給されていた電流及び鉄心に蓄積されていた磁気エネルギの一部が、第１の１次巻線３ａに流れるようになるため、２次電流Ｉ２が低下する。このとき制御装置４は、第２のスイッチング素子２に流れる電流を遮断することなく、第１のスイッチング素子１に電流を流しているため、第２の１次巻線３ｂには逆起電力が発生せず、第２の１次電流Ｉ１２及び２次電流Ｉ２は緩やかに減少する。このように、第２のスイッチング素子２をオンにしたままで、第１のスイッチング素子１をオンするので、２次電流Ｉ２を緩やかに減少させることができる。よって、第２のスイッチング素子２をオフして２次電流Ｉ２を急峻に低下させるよりも、２次電流を一定値以上に維持することが容易となる。 At time t4, the detected value of the secondary current I2 became larger than the upper limit threshold value I2_thH, so that the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off to on, and the first 1 The next winding 3a is energized. By making the first switching element 1 conductive, the current additionally supplied to the secondary winding 3c and a part of the magnetic energy stored in the iron core flow to the first primary winding 3a. Therefore, the secondary current I2 decreases. At this time, since the control device 4 causes the current to flow through the first switching element 1 without interrupting the current flowing through the second switching element 2, a counter electromotive force is applied to the second primary winding 3b. It does not occur, and the second primary current I12 and the secondary current I2 gradually decrease. In this way, since the first switching element 1 is turned on while the second switching element 2 is turned on, the secondary current I2 can be gradually reduced. Therefore, it becomes easier to maintain the secondary current above a certain value rather than turning off the second switching element 2 to sharply reduce the secondary current I2.
　時刻ｔ５で、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さくなったので、制御装置４は、第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１を、オンからオフに切り替え、第１の１次巻線３ａの通電を遮断する。第１の１次巻線３ａに電流が流れなくなるため、第２の１次巻線３ｂから供給されていた電流が２次巻線３ｃに流れ、２次電流Ｉ２が再び次第に増加する。 At time t5, the detected value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 switches the drive signal S_sw1 to the first switching element 1 from on to off, and the first 1 The energization of the next winding 3a is cut off. Since no current flows through the first primary winding 3a, the current supplied from the second primary winding 3b flows through the secondary winding 3c, and the secondary current I2 gradually increases again.
　そして、時刻ｔ６で、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなったので、制御装置４は、第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１を、オフからオンに切り替え、第１の１次巻線３ａに通電する。その後、２次電流Ｉ２が次第に減少していき、時刻ｔ７で、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さくなったので、制御装置４は、第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１を、オンからオフに切り替え、第１の１次巻線３ａの通電を遮断する。時刻ｔ８で、制御装置４は、第２のスイッチング素子２のオフ時期になったので、第２のスイッチング素子２への駆動信号Ｓ＿ｓｗ２を、オンからオフに切り替えると共に、第１のスイッチング素子１のオンオフ制御を停止し、第１のスイッチング素子１をオフのままにする。 Then, at time t6, the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH, so that the control device 4 switches the drive signal S_sw1 to the first switching element 1 from off to on, and the first The primary winding 3a of the above is energized. After that, the secondary current I2 gradually decreased, and at time t7, the detected value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 sent a drive signal to the first switching element 1. S_sw1 is switched from on to off, and the energization of the first primary winding 3a is cut off. At time t8, the control device 4 has turned off the second switching element 2, so that the drive signal S_sw2 to the second switching element 2 is switched from on to off, and the first switching element 1 The on / off control is stopped and the first switching element 1 is left off.
　このように、第２のスイッチング素子２のオン期間中に、２次電流Ｉ２の検出値に応じて、第１のスイッチング素子１をオンオフすることにより、２次電流Ｉ２を、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの範囲内に精度よく維持することができ、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 In this way, during the ON period of the second switching element 2, the secondary current I2 is set to the upper limit threshold value I2_thH and the lower limit by turning on and off the first switching element 1 according to the detected value of the secondary current I2. It can be accurately maintained within the range of the threshold value I2_thL, and the improvement of ignitability and the suppression of the increase in electrode wear can be achieved in a well-balanced manner.
＜転用例＞
　上記の実施の形態では、制御装置４は、常に、２次電流Ｉ２の検出値に応じて、第１のスイッチング素子１をオンオフする場合を例に説明した。しかし、制御装置４は、常に、２次電流Ｉ２の検出値を用いて制御する必要はなく、例えば、制御装置４は、１点火周期における動作を事前に決定しておき、次の点火周期においては、２次電流Ｉ２の検出値に関わらず、事前に決定した動作に従って、第１のスイッチング素子１をオンオフしてもよい。 <Example of diversion>
In the above-described embodiment, the case where the control device 4 always turns on / off the first switching element 1 according to the detected value of the secondary current I2 has been described as an example. However, the control device 4 does not always need to be controlled by using the detected value of the secondary current I2. For example, the control device 4 determines the operation in one ignition cycle in advance and in the next ignition cycle. May turn on / off the first switching element 1 according to a predetermined operation regardless of the detected value of the secondary current I2.
　上記の実施の形態では、上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬが、１回の点火制御期間中に変化されない場合を例に説明した。しかし、制御装置４は、１回の制御期間中に、上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬを変化させてもよい。例えば、放電期間の後半では、気筒内の圧力が高くなり、放電維持又は着火が困難になる傾向がある。制御装置４は、１回の放電期間中において、火花放電の開始後の経過時間が増加するに従って、下限閾値Ｉ２＿ｔｈＬを増加させるように構成されてもよい。この構成によれば、放電期間の後半においても、良好な着火性能を維持することができる。 In the above embodiment, the case where the upper limit threshold value I2_thH and the lower limit threshold value I2_thL are not changed during one ignition control period has been described as an example. However, the control device 4 may change the upper limit threshold value I2_thH and the lower limit threshold value I2_thL during one control period. For example, in the latter half of the discharge period, the pressure in the cylinder becomes high, and it tends to be difficult to maintain or ignite the discharge. The control device 4 may be configured to increase the lower limit threshold I2_thL as the elapsed time after the start of the spark discharge increases during one discharge period. According to this configuration, good ignition performance can be maintained even in the latter half of the discharge period.
２．実施の形態２
　次に、実施の形態２に係る点火装置１０について説明する。上記の実施の形態１と同様の構成部分は説明を省略する。本実施の形態に係る点火装置１０の基本的な構成及び処理は実施の形態１と同様である。図５は、実施の形態２に係る点火装置１０の基本構成を示す電気回路図である。本実施の形態では、点火装置１０に、２次電流検出回路７が設けられておらず、電源電圧検出回路８が設けられており、それに伴って、制御装置４における第１のスイッチング素子のオンオフ制御の処理が実施の形態１と異なる。 2. Embodiment 2
Next, the ignition device 10 according to the second embodiment will be described. The description of the same components as in the first embodiment will be omitted. The basic configuration and processing of the ignition device 10 according to the present embodiment are the same as those of the first embodiment. FIG. 5 is an electric circuit diagram showing a basic configuration of the ignition device 10 according to the second embodiment. In the present embodiment, the ignition device 10 is not provided with the secondary current detection circuit 7, but is provided with the power supply voltage detection circuit 8, and accordingly, the first switching element in the control device 4 is turned on and off. The control process is different from the first embodiment.
　電源電圧検出回路８は、直流電源６の電源電圧を検出するための回路である。電源電圧検出回路８は、例えば、分圧抵抗回路からなり、直流電源６の出力電圧に応じた電圧を出力する。或いは、電源電圧検出回路８は、直流電源６の出力電圧を、制御装置４に入力する電線とされてもよい。電源電圧検出回路８には、直流電源６の電源電圧を検出可能な回路であれば、どのような回路が用いられもよい。 The power supply voltage detection circuit 8 is a circuit for detecting the power supply voltage of the DC power supply 6. The power supply voltage detection circuit 8 is composed of, for example, a voltage dividing resistor circuit, and outputs a voltage corresponding to the output voltage of the DC power supply 6. Alternatively, the power supply voltage detection circuit 8 may be an electric wire that inputs the output voltage of the DC power supply 6 to the control device 4. As the power supply voltage detection circuit 8, any circuit may be used as long as it can detect the power supply voltage of the DC power supply 6.
＜運転状態に応じた制御パラメータの設定＞
　本実施の形態では、制御装置４は、内燃機関の運転状態と、第１のスイッチング素子１及び第２のスイッチング素子２の制御パラメータとの関係が予め設定された制御設定データを参照し、現在の内燃機関の運転状態に対応する制御パラメータを算出し、算出した制御パラメータに基づいて、火花放電の期間中に第２のスイッチング素子２をオンすると共に、第２のスイッチング素子２のオン期間中に第１のスイッチング素子１をオンオフする。 <Setting of control parameters according to operating conditions>
In the present embodiment, the control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the control parameters of the first switching element 1 and the second switching element 2 is set in advance, and is currently present. The control parameters corresponding to the operating state of the internal combustion engine are calculated, and based on the calculated control parameters, the second switching element 2 is turned on during the spark discharge period, and the second switching element 2 is turned on during the on period. The first switching element 1 is turned on and off.
　この構成によれば、２次電流検出回路７を設ける必要がなく、運転状態に応じて、適切に２次電流Ｉ２を制御することができ、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 According to this configuration, it is not necessary to provide the secondary current detection circuit 7, and the secondary current I2 can be appropriately controlled according to the operating state, and the improvement of ignitability and the suppression of the increase in electrode wear are well balanced. Can be achieved.
　例えば、第１のスイッチング素子の制御パラメータは、図６に示すような、経過時間とオン時期及びオン時期との関係が予め設定されたオンオフ計画データとされる。制御装置４は、第２のスイッチング素子２のオン後の経過時間に応じて、第１のスイッチング素子１をオンオフする。例えば、実施の形態１のような２次電流Ｉ２の挙動になるように、オンオフ計画データを予め予備試験により設定すればよい。 For example, the control parameter of the first switching element is on / off planning data in which the relationship between the elapsed time and the on time and the on time is set in advance as shown in FIG. The control device 4 turns on / off the first switching element 1 according to the elapsed time after the second switching element 2 is turned on. For example, the on / off planning data may be set in advance by a preliminary test so that the behavior of the secondary current I2 as in the first embodiment is obtained.
　図６のオンオフ計画データでは、制御装置４は、第２のスイッチング素子２のオン後の経過時間が０の時に、第１のスイッチング素子１をオフ（０）にし、第２のスイッチング素子２のオン後の経過時間が時間Ｔ１になった時に、第１のスイッチング素子１をオン（１）にし、経過時間が時間Ｔ２になった時に、第１のスイッチング素子１をオフ（０）にし、経過時間が時間Ｔ３になった時に、第１のスイッチング素子１をオン（１）にする。 In the on / off planning data of FIG. 6, the control device 4 turns off (0) the first switching element 1 when the elapsed time after the second switching element 2 is turned on is 0, and the second switching element 2 When the elapsed time after turning on reaches the time T1, the first switching element 1 is turned on (1), and when the elapsed time reaches the time T2, the first switching element 1 is turned off (0). When the time reaches the time T3, the first switching element 1 is turned on (1).
　或いは、第１のスイッチング素子の制御パラメータは、パルス幅変調制御（ＰＷＭ：Pulse Width Modulation）のオンオフ周波数及びオンデューティとされ、制御装置４は、第２のスイッチング素子２のオン期間中に、設定されたオンオフ周波数及びオンデューティに従って、パルス幅変調制御により第１のスイッチング素子１をオンオフすればよい。後述する図７に示すように、本実施の形態では、パルス幅変調制御は、オフ期間から開始される。 Alternatively, the control parameters of the first switching element are the on / off frequency and the on-duty of the pulse width modulation control (PWM), and the control device 4 is set during the on period of the second switching element 2. The first switching element 1 may be turned on / off by pulse width modulation control according to the on / off frequency and on duty. As shown in FIG. 7, which will be described later, in the present embodiment, the pulse width modulation control is started from the off period.
　第１のスイッチング素子の制御パラメータは、内燃機関の運転状態に応じて切り換えられる。例えば、内燃機関の回転速度が高くなると、１回の点火制御期間が短くなるので、それに応じて、例えば、オンオフ周波数が高くなるように制御パラメータを変化させればよい。また、高圧環境、強流動環境では放電維持に必要なエネルギが大きくなるため、２次電流が全体的に大きくなるように、制御パラメータを調整すればよい。 The control parameter of the first switching element is switched according to the operating state of the internal combustion engine. For example, as the rotation speed of the internal combustion engine increases, the one ignition control period becomes shorter. Therefore, for example, the control parameters may be changed so that the on / off frequency becomes higher. Further, in a high-voltage environment and a strong flow environment, the energy required to maintain the discharge becomes large, so the control parameters may be adjusted so that the secondary current becomes large as a whole.
　例えば、第２のスイッチング素子の制御パラメータは、放電開始後のオン時期及びオン時期が設定されたデータとされる。制御装置４は、放電開始後の経過時間がオン時期になった時に、第２のスイッチング素子２をオンにし、放電開始後の経過時間がオフ時期になった時に、第２のスイッチング素子２をオフにする。例えば、実施の形態１のような２次電流Ｉ２の挙動になるように、オン時期及びオン時期のデータを予め予備試験により設定すればよい。 For example, the control parameter of the second switching element is data in which the on-time and the on-time after the start of discharge are set. The control device 4 turns on the second switching element 2 when the elapsed time after the start of discharge is on, and turns on the second switching element 2 when the elapsed time after the start of discharge is off. Turn off. For example, the on-time and on-time data may be set in advance by a preliminary test so that the behavior of the secondary current I2 as in the first embodiment is obtained.
　第２のスイッチング素子の制御パラメータは、内燃機関の運転状態に応じて切り換えられる。例えば、内燃機関の回転速度が高くなると、１回の点火制御期間が短くなるので、それに応じて、例えば、第２のスイッチング素子のオン期間が短くなるように、制御パラメータを変化させればよい。また、高圧環境、強流動環境では放電維持に必要なエネルギが大きくなるため、２次電流が全体的に大きくなるように、オン時期が早められればよい。 The control parameter of the second switching element is switched according to the operating state of the internal combustion engine. For example, as the rotation speed of the internal combustion engine increases, the one ignition control period becomes shorter. Therefore, for example, the control parameters may be changed so that the on period of the second switching element becomes shorter. .. Further, in a high-voltage environment and a strong flow environment, the energy required for maintaining the discharge becomes large, so that the on-time may be advanced so that the secondary current becomes large as a whole.
　内燃機関の運転状態は、内燃機関の充填効率（気筒内の圧力）、内燃機関の回転速度、内燃機関の圧縮比、空燃比、排気再循環率、内燃機関の始動後の経過時間、及び内燃機関の冷却水温度のいずれか一つ以上である。内燃機関の圧縮比は、内燃機関の圧縮比を変更可能な機構が内燃機関に備えられている場合に加えられる。例えば、内燃機関の運転状態は、内燃機関の充填効率、内燃機関の回転速度、及び排気再循環率とされる。 The operating conditions of the internal combustion engine are the filling efficiency (pressure in the cylinder) of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the internal combustion engine. One or more of the cooling water temperatures of the engine. The compression ratio of the internal combustion engine is added when the internal combustion engine is provided with a mechanism capable of changing the compression ratio of the internal combustion engine. For example, the operating state of the internal combustion engine is the filling efficiency of the internal combustion engine, the rotation speed of the internal combustion engine, and the exhaust gas recirculation rate.
＜電源電圧に応じた制御パラメータの変更＞
　電源電圧Ｖ１に比例して、第１の１次巻線３ａ及び第２の１次巻線３ｂに流れる電流が変化するため、電源電圧Ｖ１に応じて２次電流Ｉ２の挙動が変化する。図７に電源電圧Ｖ１が通常の時（左側のグラフ）と、通常より大きい時（中央のグラフ）と、通常より小さい時（右側のグラフ）の２次電流Ｉ２の挙動を示す。２次電流Ｉ２は、絶対値で示されている。なお、第１のスイッチング素子１及び第２のスイッチング素子２は、後述するように、適切に制御されている。 <Change of control parameters according to power supply voltage>
Since the current flowing through the first primary winding 3a and the second primary winding 3b changes in proportion to the power supply voltage V1, the behavior of the secondary current I2 changes according to the power supply voltage V1. FIG. 7 shows the behavior of the secondary current I2 when the power supply voltage V1 is normal (graph on the left), when it is larger than normal (graph in the center), and when it is smaller than normal (graph on the right). The secondary current I2 is shown as an absolute value. The first switching element 1 and the second switching element 2 are appropriately controlled as will be described later.
　火花放電を生じるための最初の第１のスイッチング素子のオン期間は、電源電圧Ｖ１の通常時、大きい時、小さい時で変化していない。そのため、オン期間の間に鉄心に蓄積される磁気エネルギは、電源電圧Ｖ１に比例して変化し、放電開始後の２次電流Ｉ２の初期値が変化している。よって、放電開始後、２次電流Ｉ２が下限閾値Ｉ２＿ｔｈＬに到達するまでの期間は、電源電圧Ｖ１に比例して変化している。また、電源電圧Ｖ１に比例して、第２のスイッチング素子のオンによる２次電流Ｉ２の増加速度が変化している。また、電源電圧Ｖ１に比例して、第１のスイッチング素子のオンによる２次電流Ｉ２の減少速度が変化している。よって、２次電流Ｉ２を、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの範囲内に制御するための、第１のスイッチング素子のオンオフ周波数は、電源電圧Ｖ１に比例して変化している。なお、図７には、説明の容易化のために、２次電流Ｉ２、上限閾値Ｉ２＿ｔｈＨ、及び下限閾値Ｉ２＿ｔｈＬが示されているが、制御装置４は、実際にはこれらを用いて制御を行わない。 The on-period of the first first switching element for generating a spark discharge does not change when the power supply voltage V1 is normal, large, or small. Therefore, the magnetic energy stored in the iron core during the on period changes in proportion to the power supply voltage V1, and the initial value of the secondary current I2 after the start of discharge changes. Therefore, the period from the start of discharge until the secondary current I2 reaches the lower limit threshold value I2_thL changes in proportion to the power supply voltage V1. Further, the rate of increase of the secondary current I2 due to the on of the second switching element changes in proportion to the power supply voltage V1. Further, the rate of decrease of the secondary current I2 due to the on of the first switching element changes in proportion to the power supply voltage V1. Therefore, the on / off frequency of the first switching element for controlling the secondary current I2 within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL changes in proportion to the power supply voltage V1. Although the secondary current I2, the upper limit threshold value I2_thH, and the lower limit threshold value I2_thL are shown in FIG. 7 for ease of explanation, the control device 4 actually performs control using these. Absent.
　そこで、制御装置４は、電源電圧Ｖ１の検出値に基づいて、第１のスイッチング素子１及び第２のスイッチング素子２の制御パラメータを変化させ、変化された制御パラメータに基づいて、火花放電の期間中に第２のスイッチング素子２をオンすると共に、第２のスイッチング素子のオン期間中に第１のスイッチング素子１をオンオフする。 Therefore, the control device 4 changes the control parameters of the first switching element 1 and the second switching element 2 based on the detected value of the power supply voltage V1, and the spark discharge period based on the changed control parameters. The second switching element 2 is turned on, and the first switching element 1 is turned on and off during the on period of the second switching element.
　例えば、図７の例のように、電源電圧Ｖ１の検出値が大きくなるに従って、放電開始後の第２のスイッチング素子２のオン時期が早められる。また、電源電圧Ｖ１の検出値が大きくなるに従って、第２のスイッチング素子のオン期間中の第１のスイッチング素子のオンオフ周波数が高められる。 For example, as shown in the example of FIG. 7, as the detected value of the power supply voltage V1 increases, the on timing of the second switching element 2 after the start of discharge is accelerated. Further, as the detected value of the power supply voltage V1 increases, the on / off frequency of the first switching element during the on period of the second switching element is increased.
＜運転状態及び電源電圧に応じた制御パラメータの変更＞
　本実施の形態では、内燃機関の運転状態に応じても、制御パラメータが変化させる。そこで、制御装置４は、電源電圧Ｖ１及び内燃機関の運転状態と、第１のスイッチング素子１及び第２のスイッチング素子２の制御パラメータとの関係が予め設定された制御設定データを参照し、現在の電源電圧Ｖ１の検出値及び内燃機関の運転状態に対応する制御パラメータを算出し、算出した制御パラメータに基づいて、火花放電の期間中に第２のスイッチング素子２をオンすると共に、第２のスイッチング素子２のオン期間中に第１のスイッチング素子１をオンオフする。或いは、内燃機関の運転状態に、電源電圧Ｖ１を必ず含ませればよい。 <Change of control parameters according to operating conditions and power supply voltage>
In the present embodiment, the control parameters are changed according to the operating state of the internal combustion engine. Therefore, the control device 4 refers to the control setting data in which the relationship between the power supply voltage V1 and the operating state of the internal combustion engine and the control parameters of the first switching element 1 and the second switching element 2 is preset, and is currently used. The control parameters corresponding to the detected value of the power supply voltage V1 and the operating state of the internal combustion engine are calculated, and based on the calculated control parameters, the second switching element 2 is turned on during the spark discharge period, and the second switching element 2 is turned on. The first switching element 1 is turned on and off during the on period of the switching element 2. Alternatively, the power supply voltage V1 may always be included in the operating state of the internal combustion engine.
＜制御挙動＞
　図７に示す例は、第１のスイッチング素子の制御パラメータが、図６に示したようなオンオフ計画データである場合の例である。２次電流Ｉ２が、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの間を振動するように、予備試験等により、内燃機関の運転状態毎及び電源電圧Ｖ１毎にオンオフ計画データが予め設定されている。 <Control behavior>
The example shown in FIG. 7 is an example in which the control parameter of the first switching element is the on / off planning data as shown in FIG. On / off plan data is preset for each operating state of the internal combustion engine and for each power supply voltage V1 by a preliminary test or the like so that the secondary current I2 oscillates between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
　詳細な説明は省略するが、制御装置４は、放電開始後の経過時間が、内燃機関の運転状態及び電源電圧Ｖ１の検出値に基づいて決定された第２のスイッチング素子のオン時期に到達した時（時刻ｔ１３、ｔ２３、ｔ３３）に、第２のスイッチング素子（Ｓ＿ｓｗ２）をオン（１）している。制御装置４は、第２のスイッチング素子をオンした後の経過時間が、運転状態及び電源電圧Ｖ１の検出値に基づいて決定された１回目のオン時期に到達した時（時刻ｔ１４、ｔ２４、ｔ３４）に、第１のスイッチング素子（Ｓ＿ｓｗ１）をオン（１）している。制御装置４は、第２のスイッチング素子をオンした後の経過時間が、運転状態及び電源電圧Ｖ１の検出値に基づいて決定された１回目のオフ時期に到達した時（時刻ｔ１５、ｔ２５、ｔ３５）に、第１のスイッチング素子をオフ（０）している。その後、同様に、制御装置４は、第２のスイッチング素子をオンした後の経過時間が、２回目以降のオン時期又はオフ時期に到達する毎に、第１のスイッチング素子をオン又はオフする。そして、制御装置４は、放電開始後の経過時間が、運転状態及び電源電圧Ｖ１の検出値に基づいて決定された第２のスイッチング素子のオフ時期に到達した時（時刻ｔ１６、ｔ２６、ｔ３６）に、第２のスイッチング素子をオフ（０）し、第１のスイッチング素子をオフ（０）している。 Although detailed description will be omitted, in the control device 4, the elapsed time after the start of discharge has reached the on time of the second switching element determined based on the operating state of the internal combustion engine and the detected value of the power supply voltage V1. At the time (time t13, t23, t33), the second switching element (S_sw2) is turned on (1). When the elapsed time after turning on the second switching element reaches the first on time determined based on the operating state and the detected value of the power supply voltage V1, the control device 4 reaches the first on time (time t14, t24, t34). ), The first switching element (S_sw1) is turned on (1). The control device 4 reaches when the elapsed time after turning on the second switching element reaches the first off time determined based on the operating state and the detected value of the power supply voltage V1 (time t15, t25, t35). ), The first switching element is turned off (0). After that, similarly, the control device 4 turns on or off the first switching element every time the elapsed time after turning on the second switching element reaches the second on or off time. Then, the control device 4 reaches when the elapsed time after the start of discharge reaches the off time of the second switching element determined based on the operating state and the detected value of the power supply voltage V1 (time t16, t26, t36). The second switching element is turned off (0) and the first switching element is turned off (0).
３．実施の形態３
　次に、実施の形態３に係る点火装置１０について説明する。上記の実施の形態１と同様の構成部分は説明を省略する。本実施の形態に係る点火装置１０の基本的な構成及び処理は実施の形態１と同様である。本実施の形態では、制御装置４における第１のスイッチング素子のオンオフ制御の処理が実施の形態１と異なる。 3. 3. Embodiment 3
Next, the ignition device 10 according to the third embodiment will be described. The description of the same components as in the first embodiment will be omitted. The basic configuration and processing of the ignition device 10 according to the present embodiment are the same as those of the first embodiment. In the present embodiment, the on / off control process of the first switching element in the control device 4 is different from that in the first embodiment.
　本実施の形態では、制御装置４は、第２のスイッチング素子２のオン期間中に、パルス幅変調制御（ＰＷＭ：Pulse Width Modulation）により第１のスイッチング素子１をオンオフする。この構成によれば、２次電流Ｉ２の検出遅れ等に影響されずに、計画的に第１のスイッチング素子１をオンオフできる。 In the present embodiment, the control device 4 turns on / off the first switching element 1 by pulse width modulation control (PWM: Pulse Width Modulation) during the on period of the second switching element 2. According to this configuration, the first switching element 1 can be systematically turned on and off without being affected by the detection delay of the secondary current I2 or the like.
　制御装置４は、第２のスイッチング素子のオン期間中に、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなった時に、パルス幅変調制御を開始する。パルス幅変調制御は、オン期間から開始される。この構成によれば、パルス幅変調制御を開始することにより、２次電流Ｉ２が上限閾値Ｉ２＿ｔｈＨよりも大きくなることを抑制できる。 The control device 4 starts the pulse width modulation control when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH during the ON period of the second switching element. Pulse width modulation control starts from the on period. According to this configuration, by starting the pulse width modulation control, it is possible to prevent the secondary current I2 from becoming larger than the upper limit threshold value I2_thH.
　制御装置４は、２次電流Ｉ２の検出値が目標範囲内に収まるように、パルス幅変調制御のオンデューティを変化させる。この構成によれば、２次電流Ｉ２の検出遅れ等に影響され難いパルス幅変調制御の利点を生かしつつ、２次電流Ｉ２を精度良く目標範囲内に収めることができる。よって、目標範囲の設定により、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 The control device 4 changes the on-duty of the pulse width modulation control so that the detected value of the secondary current I2 falls within the target range. According to this configuration, the secondary current I2 can be accurately contained within the target range while taking advantage of the pulse width modulation control that is not easily affected by the detection delay of the secondary current I2. Therefore, by setting the target range, it is possible to improve the ignitability and suppress the increase in electrode wear in a well-balanced manner.
　各点火周期のオンデューティの初期値は、実施の形態２と同様に内燃機関の運転状態及び電源電圧Ｖ１の一方又は双方に基づいて設定されてもよい。又は、前回の点火周期におけるオンデューティの最終値に設定されてもよい。この場合は、最初の点火周期におけるオンデューティは、０．５程度に設定されればよい。 The initial value of the on-duty of each ignition cycle may be set based on one or both of the operating state of the internal combustion engine and the power supply voltage V1 as in the second embodiment. Alternatively, it may be set to the final value of on-duty in the previous ignition cycle. In this case, the on-duty in the first ignition cycle may be set to about 0.5.
　或いは、オンデューティは、実施の形態２と同様に内燃機関の運転状態及び電源電圧Ｖ１の一方又は双方に基づいて設定されたフィードフォーワード値と、２次電流Ｉ２の検出値に応じて変化させるフィードバック値との合計値とされてもよく、フィードバック値は、次回の点火周期に引き継がれてもよく、点火周期毎にリセットされてもよい。 Alternatively, the on-duty is changed according to the feed forward value set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1 and the detected value of the secondary current I2 as in the second embodiment. It may be the total value with the feedback value, and the feedback value may be carried over to the next ignition cycle, or may be reset at each ignition cycle.
　パルス幅変調制御のオンオフ周波数は、実施の形態２と同様に、内燃機関の運転状態及び電源電圧Ｖ１の一方又は双方に基づいて設定され、例えば、１ｋＨｚから５０ｋＨｚ程度の範囲内に設定される。 The on / off frequency of the pulse width modulation control is set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1, as in the second embodiment, and is set in the range of, for example, about 1 kHz to 50 kHz.
　本実施の形態では、制御装置４は、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなった場合に、パルス幅変調制御のオンデューティを増加させる。この構成によれば、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨを上回ることを抑制でき、上限閾値Ｉ２＿ｔｈＨの設定値により、電極消耗の増加抑制を管理できる。 In the present embodiment, the control device 4 increases the on-duty of the pulse width modulation control when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH. According to this configuration, it is possible to suppress the detection value of the secondary current I2 from exceeding the upper limit threshold value I2_thH, and the suppression of the increase in electrode wear can be managed by the set value of the upper limit threshold value I2_thH.
　また、制御装置４は、２次電流Ｉ２の検出値が、上限閾値Ｉ２＿ｔｈＨ以下に設定された下限閾値Ｉ２＿ｔｈＬよりも小さくなった場合に、パルス幅変調制御のオンデューティを減少させる。この構成によれば、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬを下回ることを抑制でき、下限閾値Ｉ２＿ｔｈＬの設定値により、着火性の向上を管理できる。 Further, the control device 4 reduces the on-duty of the pulse width modulation control when the detected value of the secondary current I2 becomes smaller than the lower limit threshold value I2_thL set below the upper limit threshold value I2_thH. According to this configuration, it is possible to suppress the detection value of the secondary current I2 from falling below the lower limit threshold value I2_thL, and the improvement of the ignitability can be managed by the set value of the lower limit threshold value I2_thL.
　上限閾値Ｉ２＿ｔｈＨ及び下限閾値Ｉ２＿ｔｈＬは、実施の形態１と同様に、運転状態に基づいて設定される。なお、以下で説明する例では、下限閾値Ｉ２＿ｔｈＬは、上限閾値Ｉ２＿ｔｈＨよりも小さい値に設定されているが、上限閾値Ｉ２＿ｔｈＨと同じ値に設定されてもよい。 The upper limit threshold value I2_thH and the lower limit threshold value I2_thL are set based on the operating state as in the first embodiment. In the example described below, the lower limit threshold value I2_thL is set to a value smaller than the upper limit threshold value I2_thH, but may be set to the same value as the upper limit threshold value I2_thH.
　なお、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとが同じ値に設定されている場合は、制御装置４は、上限閾値Ｉ２＿ｔｈＨ（又は下限閾値Ｉ２＿ｔｈＬ）と２次電流Ｉ２の検出値との偏差に基づいた、積分制御又は比例積分制御等のフィードバック制御により、パルス幅変調制御のオンデューティを変化させてもよい。 When the upper limit threshold value I2_thH and the lower limit threshold value I2_thL are set to the same value, the control device 4 is based on the deviation between the upper limit threshold value I2_thH (or the lower limit threshold value I2_thL) and the detected value of the secondary current I2. The on-duty of the pulse width modulation control may be changed by feedback control such as integral control or proportional integral control.
＜オンオフ制御のフローチャート＞
　本実施の形態に係るオンオフ制御の処理は、図８に示すフローチャートのように構成できる。制御装置４は、演算周期毎に図８のフローチャートの処理を繰り返し実行する。まず、ステップＳ２０１で、制御装置４は、第２のスイッチング素子２（駆動信号Ｓ＿ｓｗ２）をオン（１）にしているか否かを判定する。制御装置４は、第２のスイッチング素子２がオンにされていないと判定した場合は、第２のスイッチング素子２のオン期間中でないので、ステップＳ２０５に進み、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭをオフ（０）に設定し、ステップＳ２０６に進み、第１のスイッチング素子１（駆動信号Ｓ＿ｓｗ１）をオフ（０）にして、パルス幅変調制御の実行を停止し、処理を終了する。一方、制御装置４は、ステップＳ２０１で第２のスイッチング素子２がオンにされていると判定した場合は、ステップＳ２０２に進む。 <Flowchart of on / off control>
The on / off control process according to the present embodiment can be configured as shown in the flowchart shown in FIG. The control device 4 repeatedly executes the process of the flowchart of FIG. 8 for each calculation cycle. First, in step S201, the control device 4 determines whether or not the second switching element 2 (drive signal S_sw2) is turned on (1). When the control device 4 determines that the second switching element 2 is not turned on, it is not during the on period of the second switching element 2, so the process proceeds to step S205, and the execution determination information S_PWM of the pulse width modulation control is performed. Is set to off (0), the process proceeds to step S206, the first switching element 1 (drive signal S_sw1) is turned off (0), the execution of pulse width modulation control is stopped, and the process is terminated. On the other hand, if the control device 4 determines in step S201 that the second switching element 2 is turned on, the control device 4 proceeds to step S202.
　ステップＳ２０２で、制御装置４は、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭがオン（１）に設定されているか否かを判定する。制御装置４は、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭがオン（１）にされていないと判定した場合は、ステップＳ２０３に進み、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨより大きいか否かを判定する。制御装置４は、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨより大きいと判定した場合は、ステップＳ２０４に進み、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭをオン（１）に設定し、パルス幅変調制御を開始する。制御装置４は、パルス幅変調制御の開始時は、オン期間から開始する。 In step S202, the control device 4 determines whether or not the execution determination information S_PWM of the pulse width modulation control is set to ON (1). If the control device 4 determines that the execution determination information S_PWM of the pulse width modulation control is not turned on (1), the process proceeds to step S203, and whether or not the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH. To judge. When the control device 4 determines that the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH, the process proceeds to step S204, the execution determination information S_PWM of the pulse width modulation control is set to ON (1), and the pulse width modulation is performed. Start control. The control device 4 starts from the on period when the pulse width modulation control is started.
　一方、制御装置４は、ステップＳ２０２でパルス幅変調制御の実行判定情報Ｓ＿ＰＷＭがオン（１）にされていると判定した場合は、ステップＳ２０７に進み、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きいか否かを判定する。制御装置４は、ステップＳ２０７で２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きいと判定した場合は、ステップＳ２０８に進み、オンデューティＤｕｔｙを、変化幅Δｄｕｔｙだけ増加させた後、処理を終了する。増加されたオンデューティＤｕｔｙは、実行中のパルス幅変調制御に反映される。変化幅Δｄｕｔｙは、演算周期、放電期間、制御応答を考慮して設定されるが、例えば、０．０５程度に設定される。変化幅Δｄｕｔｙが小さいほど、細かく電流値を調整できるが制御応答が遅くなり、変化幅Δｄｕｔｙが大きいほど制御応答が早くなるが、細かい電流値を調整しにくくなる。 On the other hand, when the control device 4 determines in step S202 that the execution determination information S_PWM of the pulse width modulation control is turned on (1), the process proceeds to step S207, and the detected value of the secondary current I2 is the upper limit threshold value I2_thH. Determine if it is greater than. When the control device 4 determines in step S207 that the detected value of the secondary current I2 is larger than the upper limit threshold value I2_thH, the control device 4 proceeds to step S208, increases the on-duty duty by the change width Δduty, and then ends the process. To do. The increased on-duty duty is reflected in the pulse width modulation control in progress. The change width Δduty is set in consideration of the calculation cycle, the discharge period, and the control response, and is set to, for example, about 0.05. The smaller the change width Δduty, the finer the current value can be adjusted, but the control response becomes slower, and the larger the change width Δduty, the faster the control response, but it becomes difficult to finely adjust the current value.
　一方、制御装置４は、ステップＳ２０７で２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくないと判定した場合は、ステップＳ２０９に進み、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さいか否かを判定する。制御装置４は、ステップＳ２０９で２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さいと判定した場合は、ステップＳ２１０に進み、オンデューティＤｕｔｙを、変化幅Δｄｕｔｙだけ減少させた後、処理を終了する。減少されたオンデューティＤｕｔｙは、実行中のパルス幅変調制御に反映される。一方、制御装置４は、ステップＳ２０９で２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬよりも小さくないと判定した場合は、オンデューティＤｕｔｙを変化させずに処理を終了する。 On the other hand, if the control device 4 determines in step S207 that the detected value of the secondary current I2 is not larger than the upper limit threshold value I2_thH, the control device 4 proceeds to step S209 and the detected value of the secondary current I2 is smaller than the lower limit threshold value I2_thL. Judge whether or not. When the control device 4 determines in step S209 that the detected value of the secondary current I2 is smaller than the lower limit threshold value I2_thL, the control device 4 proceeds to step S210, reduces the on-duty duty by the change width Δduty, and then ends the process. To do. The reduced on-duty duty is reflected in the pulse width modulation control in progress. On the other hand, when the control device 4 determines in step S209 that the detected value of the secondary current I2 is not smaller than the lower limit threshold value I2_thL, the control device 4 ends the process without changing the on-duty duty.
＜制御挙動＞
　図９に示すタイムチャートを用いて、制御挙動を説明する。図９において、２次電流Ｉ２は、絶対値で示されている。図９の時刻ｔ５１から時刻ｔ５２は、図４の時刻ｔ１から時刻ｔ２までと同様であるので、説明を省略する。 <Control behavior>
The control behavior will be described with reference to the time chart shown in FIG. In FIG. 9, the secondary current I2 is shown as an absolute value. Since the time t51 to the time t52 in FIG. 9 is the same as the time t1 to the time t2 in FIG. 4, the description thereof will be omitted.
　時刻ｔ５２で、火花放電が開始すると、２次電流Ｉ２がステップ的にゼロから増加した後、鉄心に蓄積されていた磁気エネルギが減少するに従って、次第に減少していく。 When the spark discharge starts at time t52, the secondary current I2 increases stepwise from zero, and then gradually decreases as the magnetic energy stored in the iron core decreases.
　時刻ｔ５３で、制御装置４は、２次電流Ｉ２の検出値が、下限閾値Ｉ２＿ｔｈＬより小さくなったので、第２のスイッチング素子２への駆動信号Ｓ＿ｓｗ２を、オフ（０）からオン（１）に切り替え、第２の１次巻線３ｂに通電する。通電開始後、２次電流Ｉ２が次第に増加していく。 At time t53, the detection value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 changed the drive signal S_sw2 to the second switching element 2 from off (0) to on (1). It is switched and the second primary winding 3b is energized. After the start of energization, the secondary current I2 gradually increases.
　時刻ｔ５４で、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなったので、制御装置４は、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭをオン（１）にし、パルス幅変調制御を開始している。制御装置４は、パルス幅変調制御の開始時にオン期間から開始するので、時刻ｔ５４で第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１がオン（１）されている。その後、時刻ｔ５５までは、２次電流Ｉ２は、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬの範囲内に収まっているので、オンデューティＤｕｔｙは変化されていないが、２次電流Ｉ２の平均値が次第に減少している。 At time t54, the detected value of the secondary current I2 became larger than the upper limit threshold value I2_thH, so that the control device 4 turned on the execution determination information S_PWM of the pulse width modulation control (1) and started the pulse width modulation control. ing. Since the control device 4 starts from the on period at the start of the pulse width modulation control, the drive signal S_sw1 to the first switching element 1 is turned on (1) at time t54. After that, until the time t55, the secondary current I2 is within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL, so that the on-duty duty is not changed, but the average value of the secondary current I2 gradually decreases. ing.
　時刻ｔ５５で、２次電流Ｉ２の検出値が下限閾値Ｉ２＿ｔｈＬより小さくなったので、制御装置４は、オンデューティＤｕｔｙを、変化幅Δｄｕｔｙだけ減少させている。オンデューティＤｕｔｙの減少により、２次電流Ｉ２の平均値が次第に増加している。そして、時刻ｔ５６で、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨより大きくなったので、制御装置４は、オンデューティＤｕｔｙを、変化幅Δｄｕｔｙだけ増加させている。そして、時刻ｔ５７で、制御装置４は、第２のスイッチング素子２のオフ時期になったので、第２のスイッチング素子２を、オンからオフに切り替えると共に、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭをオフ（０）にし、パルス幅変調制御を停止し、第１のスイッチング素子１をオフにする。 At time t55, the detected value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 reduces the on-duty duty by the change width Δduty. Due to the decrease in on-duty duty, the average value of the secondary current I2 is gradually increasing. Then, at time t56, the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH, so that the control device 4 increases the on-duty duty by the change width Δduty. Then, at time t57, the control device 4 has turned off the second switching element 2, so that the second switching element 2 is switched from on to off, and the execution determination information S_PWM of the pulse width modulation control is displayed. It is turned off (0), the pulse width modulation control is stopped, and the first switching element 1 is turned off.
　このように、第２のスイッチング素子２のオン期間中に、２次電流Ｉ２の検出値に応じて、第１のスイッチング素子１のパルス幅変調制御のオンデューティを変化させることで、２次電流Ｉ２を、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの範囲内に精度よく維持することができ、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 In this way, during the on period of the second switching element 2, the on-duty of the pulse width modulation control of the first switching element 1 is changed according to the detected value of the secondary current I2, so that the secondary current I2 can be accurately maintained within the range of the upper limit threshold value I2_thH and the lower limit threshold value I2_thL, and improvement of ignitability and suppression of increase in electrode wear can be achieved in a well-balanced manner.
＜転用例＞
　上記の実施の形態３では、制御装置４は、常に、２次電流Ｉ２の検出値に応じて、パルス幅変調制御のオンデューティを変化させる場合を例に説明した。しかし、制御装置４は、常に、２次電流Ｉ２の検出値を用いて制御する必要はなく、例えば、制御装置４は、１点火周期における動作を事前に決定しておき、次の点火周期においては、２次電流Ｉ２の検出値に関わらず、事前に決定した動作に従って、第１のスイッチング素子１をオンオフしてもよい。 <Example of diversion>
In the third embodiment, the case where the control device 4 always changes the on-duty of the pulse width modulation control according to the detected value of the secondary current I2 has been described as an example. However, the control device 4 does not always need to be controlled by using the detected value of the secondary current I2. For example, the control device 4 determines the operation in one ignition cycle in advance and in the next ignition cycle. May turn on / off the first switching element 1 according to a predetermined operation regardless of the detected value of the secondary current I2.
４．実施の形態４
　次に、実施の形態４に係る点火装置１０について説明する。上記の実施の形態１と同様の構成部分は説明を省略する。本実施の形態に係る点火装置１０の基本的な構成及び処理は実施の形態１と同様である。本実施の形態では、制御装置４における第１のスイッチング素子のオンオフ制御の処理が実施の形態１と異なる。 4. Embodiment 4
Next, the ignition device 10 according to the fourth embodiment will be described. The description of the same components as in the first embodiment will be omitted. The basic configuration and processing of the ignition device 10 according to the present embodiment are the same as those of the first embodiment. In the present embodiment, the on / off control process of the first switching element in the control device 4 is different from that in the first embodiment.
　実施の形態３と同様に、制御装置４は、第２のスイッチング素子２のオン期間中に、パルス幅変調制御（ＰＷＭ：Pulse Width Modulation）により第１のスイッチング素子１をオンオフする。 Similar to the third embodiment, the control device 4 turns on / off the first switching element 1 by pulse width modulation control (PWM: Pulse Width Modulation) during the on period of the second switching element 2.
　制御装置４は、第２のスイッチング素子のオン期間中に、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなった時に、パルス幅変調制御を開始する。パルス幅変調制御は、オン期間から開始される。 The control device 4 starts the pulse width modulation control when the detected value of the secondary current I2 becomes larger than the upper limit threshold value I2_thH during the ON period of the second switching element. Pulse width modulation control starts from the on period.
　本実施の形態では、制御装置４は、２次電流Ｉ２の検出値が目標範囲内に収まるように、パルス幅変調制御のオンオフ周波数ｆｐｗｍを変化させる。この構成によれば、オンオフ周波数ｆｐｗｍを増加させることにより、２次電流Ｉ２の振幅を減少させ、オンオフ周波数ｆｐｗｍを減少させることにより、２次電流Ｉ２の振幅を増加させることができる。よって、２次電流Ｉ２の検出値が目標範囲内に収まるように、２次電流Ｉ２の振動範囲を変化させることができ、目標範囲の設定により、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 In the present embodiment, the control device 4 changes the on / off frequency fpwm of the pulse width modulation control so that the detected value of the secondary current I2 falls within the target range. According to this configuration, the amplitude of the secondary current I2 can be decreased by increasing the on / off frequency fpwm, and the amplitude of the secondary current I2 can be increased by decreasing the on / off frequency fpww. Therefore, the vibration range of the secondary current I2 can be changed so that the detected value of the secondary current I2 falls within the target range, and by setting the target range, improvement of ignitability and suppression of increase in electrode wear are balanced. Can be achieved well.
　制御装置４は、２次電流Ｉ２の検出値の振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも大きくなった場合に、パルス幅変調制御のオンオフ周波数ｆｐｗｍを増加させる。この構成によれば、２次電流Ｉ２の振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも大きくならないようにでき、目標振幅ΔＩ２＿ｔｈの設定により、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 The control device 4 increases the on / off frequency fpwm of the pulse width modulation control when the amplitude ΔI2 of the detected value of the secondary current I2 becomes larger than the target amplitude ΔI2_th. According to this configuration, the amplitude ΔI2 of the secondary current I2 can be prevented from becoming larger than the target amplitude ΔI2_th, and by setting the target amplitude ΔI2_th, improvement of ignitability and suppression of increase in electrode wear can be achieved in a well-balanced manner. it can.
　また、制御装置４は、２次電流の検出値の振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも小さくなった場合に、パルス幅変調制御のオンオフ周波数ｆｐｗｍを減少させる。この構成によれば、２次電流Ｉ２の振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも小さくならないようにでき、着火性の向上及び電極消耗の増加抑制を適切にバランスさせることができる。 Further, the control device 4 reduces the on / off frequency fpwm of the pulse width modulation control when the amplitude ΔI2 of the detected value of the secondary current becomes smaller than the target amplitude ΔI2_th. According to this configuration, the amplitude ΔI2 of the secondary current I2 can be prevented from becoming smaller than the target amplitude ΔI2_th, and the improvement of ignitability and the suppression of the increase in electrode wear can be appropriately balanced.
　制御装置４は、オンオフ周波数ｆｐｗｍの１周期内の２次電流Ｉ２の検出値の最大値と最小値を判定し、最大値と最小値との偏差により振幅ΔＩ２を算出する。 The control device 4 determines the maximum value and the minimum value of the detected value of the secondary current I2 within one cycle of the on / off frequency fpwm, and calculates the amplitude ΔI2 from the deviation between the maximum value and the minimum value.
　制御装置４は、内燃機関の運転状態と、目標振幅ΔＩ２＿ｔｈとの関係が予め設定された制御設定データを参照し、現在の内燃機関の運転状態に対応する目標振幅ΔＩ２＿ｔｈを算出する。なお、内燃機関の運転状態には、上述した種類の運転状態が用いられる。 The control device 4 refers to the control setting data in which the relationship between the operating state of the internal combustion engine and the target amplitude ΔI2_th is set in advance, and calculates the target amplitude ΔI2_th corresponding to the current operating state of the internal combustion engine. As the operating state of the internal combustion engine, the above-mentioned type of operating state is used.
　目標振幅ΔＩ２＿ｔｈは、予備試験等により予め設定されたものが、記憶装置９１に格納され、読み出される。或いは、制御装置４は、機械学習等により目標振幅ΔＩ２＿ｔｈを学習し、学習値を用いてもよい。 The target amplitude ΔI2_th set in advance by a preliminary test or the like is stored in the storage device 91 and read out. Alternatively, the control device 4 may learn the target amplitude ΔI2_th by machine learning or the like and use the learned value.
　或いは、目標振幅ΔＩ２＿ｔｈは、上記の各実施の形態で用いた上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの偏差により設定されてもよい（ΔＩ２＿ｔｈ＝Ｉ２＿ｈｔＨ－Ｉ２＿ｈｔＬ）。 Alternatively, the target amplitude ΔI2_th may be set by the deviation between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL used in each of the above embodiments (ΔI2_th = I2_htH-I2_htL).
　各点火周期のオンオフ周波数ｆｐｗｍの初期値は、実施の形態２と同様に内燃機関の運転状態及び電源電圧Ｖ１の一方又は双方に基づいて設定されてもよい。又は、前回の点火周期におけるオンオフ周波数ｆｐｗｍの最終値に設定されてもよい。この場合は、最初の点火周期におけるオンオフ周波数ｆｐｗｍは、１ｋＨｚから５０ｋＨｚ程度の範囲内に設定されればよい。 The initial value of the on / off frequency fpwm of each ignition cycle may be set based on one or both of the operating state of the internal combustion engine and the power supply voltage V1 as in the second embodiment. Alternatively, it may be set to the final value of the on / off frequency fpwm in the previous ignition cycle. In this case, the on / off frequency fpwm in the first ignition cycle may be set within the range of about 1 kHz to 50 kHz.
　或いは、オンオフ周波数ｆｐｗｍは、実施の形態２と同様に内燃機関の運転状態及び電源電圧Ｖ１の一方又は双方に基づいて設定されたフィードフォーワード値と、２次電流Ｉ２の検出値に応じて変化させるフィードバック値との合計値とされてもよく、フィードバック値は、次回の点火周期に引き継がれてもよく、点火周期毎にリセットされてもよい。 Alternatively, the on / off frequency fpwm changes according to the feed forward value set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1 and the detected value of the secondary current I2 as in the second embodiment. It may be the total value with the feedback value to be made, and the feedback value may be taken over in the next ignition cycle, or may be reset at each ignition cycle.
　パルス幅変調制御のオンデューティは、実施の形態２と同様に、内燃機関の運転状態及び電源電圧Ｖ１の一方又は双方に基づいて設定される。或いは、オンデューティは、実施の形態３のように、２次電流Ｉ２の検出値に応じて変化されてもよい。 The on-duty of the pulse width modulation control is set based on the operating state of the internal combustion engine and one or both of the power supply voltage V1, as in the second embodiment. Alternatively, the on-duty may be changed according to the detected value of the secondary current I2 as in the third embodiment.
　なお、制御装置４は、目標振幅ΔＩ２＿ｔｈと２次電流Ｉ２の検出値の振幅ΔＩ２との偏差に基づいた、積分制御又は比例積分制御等のフィードバック制御により、パルス幅変調制御のオンオフ周波数ｆｐｗｍを変化させてもよい。 The control device 4 changes the on / off frequency fpwm of the pulse width modulation control by feedback control such as integral control or proportional integral control based on the deviation between the target amplitude ΔI2_th and the amplitude ΔI2 of the detected value of the secondary current I2. You may let me.
＜オンオフ制御のフローチャート＞
　本実施の形態に係るオンオフ制御の処理は、図１０に示すフローチャートのように構成できる。制御装置４は、演算周期毎に図１０のフローチャートの処理を繰り返し実行する。まず、図１０のステップＳ３０１からステップＳ３０６は、実施の形態３の図８のステップＳ２０１からステップＳ２０６と同様であるので説明を省略する。 <Flowchart of on / off control>
The on / off control process according to the present embodiment can be configured as shown in the flowchart shown in FIG. The control device 4 repeatedly executes the process of the flowchart of FIG. 10 for each calculation cycle. First, since steps S301 to S306 of FIG. 10 are the same as steps S201 to S206 of FIG. 8 of the third embodiment, description thereof will be omitted.
　制御装置４は、ステップＳ３０２でパルス幅変調制御の実行判定情報Ｓ＿ＰＷＭがオン（１）にされていると判定した場合は、ステップＳ３０７に進み、２次電流Ｉ２の検出値の振幅ΔＩ２が目標振幅ΔＩ２＿ｔｈよりも大きいか否かを判定する。目標振幅ΔＩ２＿ｔｈは、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの偏差により設定されてもよい。 When the control device 4 determines in step S302 that the execution determination information S_PWM of the pulse width modulation control is turned on (1), the process proceeds to step S307, and the amplitude ΔI2 of the detected value of the secondary current I2 is the target amplitude. It is determined whether or not it is larger than ΔI2_th. The target amplitude ΔI2_th may be set by the deviation between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
　制御装置４は、ステップＳ３０７で２次電流Ｉ２の検出値の振幅ΔＩ２が目標振幅ΔＩ２＿ｔｈよりも大きいと判定した場合は、ステップＳ３０８に進み、オンオフ周波数ｆｐｗｍを、周波数変化幅Δｆだけ増加させた後、処理を終了する。増加されたオンオフ周波数ｆｐｗｍは、実行中のパルス幅変調制御に反映される。周波数変化幅Δｆは、演算周期、放電期間、制御応答を考慮して設定されるが、例えば、１ｋＨｚ程度に設定される。周波数変化幅Δｆが小さいほど、細かく電流値を調整できるが制御応答が遅くなり、周波数変化幅Δｆが大きいほど制御応答が早くなるが、細かい電流値を調整しにくくなる。 If the control device 4 determines in step S307 that the amplitude ΔI2 of the detected value of the secondary current I2 is larger than the target amplitude ΔI2_th, the controller 4 proceeds to step S308, increases the on / off frequency fpww by the frequency change width Δf, and then increases the on / off frequency fpwm by the frequency change width Δf. , End the process. The increased on / off frequency fpwm is reflected in the pulse width modulation control during execution. The frequency change width Δf is set in consideration of the calculation cycle, the discharge period, and the control response, and is set to, for example, about 1 kHz. The smaller the frequency change width Δf, the finer the current value can be adjusted, but the control response becomes slower, and the larger the frequency change width Δf, the faster the control response, but it becomes difficult to finely adjust the current value.
　一方、制御装置４は、ステップＳ３０７で２次電流Ｉ２の検出値の振幅ΔＩ２が目標振幅ΔＩ２＿ｔｈよりも大きくないと判定した場合は、ステップＳ３０９に進み、オンオフ周波数ｆｐｗｍを、周波数変化幅Δｆだけ減少させた後、処理を終了する。減少されたオンオフ周波数ｆｐｗｍは、実行中のパルス幅変調制御に反映される。 On the other hand, if the control device 4 determines in step S307 that the amplitude ΔI2 of the detected value of the secondary current I2 is not larger than the target amplitude ΔI2_th, the control device 4 proceeds to step S309 and reduces the on / off frequency fpwm by the frequency change width Δf. After that, the process ends. The reduced on / off frequency fpwm is reflected in the pulse width modulation control during execution.
　なお、図１０のフローチャートの処理に加えて、図８のフローチャートの処理が行われてもよい。例えば、図１０のステップＳ３０７からステップＳ３０９の処理の後に、図８のステップＳ２０７からステップＳ２１０の処理が行われればよい。 Note that, in addition to the processing of the flowchart of FIG. 10, the processing of the flowchart of FIG. 8 may be performed. For example, after the processing of steps S307 to S309 of FIG. 10, the processing of steps S207 to S210 of FIG. 8 may be performed.
＜制御挙動＞
　図１１に示すタイムチャートを用いて、制御挙動を説明する。図１１において、２次電流Ｉ２は、絶対値で示されている。図１１の時刻ｔ６１から時刻ｔ６２は、図４の時刻ｔ１から時刻ｔ２までと同様であるので、説明を省略する。 <Control behavior>
The control behavior will be described with reference to the time chart shown in FIG. In FIG. 11, the secondary current I2 is shown as an absolute value. Since the time t61 to the time t62 in FIG. 11 is the same as the time t1 to the time t2 in FIG. 4, the description thereof will be omitted.
　時刻ｔ６２で、火花放電が開始すると、２次電流Ｉ２（絶対値）がステップ的にゼロから増加した後、鉄心に蓄積されていた磁気エネルギが減少するに従って、次第に減少していく。 When the spark discharge starts at time t62, the secondary current I2 (absolute value) increases stepwise from zero, and then gradually decreases as the magnetic energy stored in the iron core decreases.
　時刻ｔ６３で、制御装置４は、２次電流Ｉ２の検出値が、下限閾値Ｉ２＿ｔｈＬより小さくなったので、第２のスイッチング素子２への駆動信号Ｓ＿ｓｗ２を、オフ（０）からオン（１）に切り替え、第２の１次巻線３ｂに通電する。通電開始後、２次電流Ｉ２が次第に増加していく。 At time t63, the detection value of the secondary current I2 became smaller than the lower limit threshold value I2_thL, so that the control device 4 changed the drive signal S_sw2 to the second switching element 2 from off (0) to on (1). It is switched and the second primary winding 3b is energized. After the start of energization, the secondary current I2 gradually increases.
　時刻ｔ６４で、２次電流Ｉ２の検出値が上限閾値Ｉ２＿ｔｈＨよりも大きくなったので、制御装置４は、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭをオン（１）にし、パルス幅変調制御を開始している。制御装置４は、パルス幅変調制御の開始時にオン期間から開始するので、時刻ｔ６４で第１のスイッチング素子１への駆動信号Ｓ＿ｓｗ１がオン（１）されている。第１のスイッチング素子１がオンされた後、２次電流Ｉ２は減少する。 At time t64, the detected value of the secondary current I2 became larger than the upper limit threshold value I2_thH, so that the control device 4 turned on the execution determination information S_PWM of the pulse width modulation control (1) and started the pulse width modulation control. ing. Since the control device 4 starts from the on period at the start of the pulse width modulation control, the drive signal S_sw1 to the first switching element 1 is turned on (1) at time t64. After the first switching element 1 is turned on, the secondary current I2 decreases.
　時刻ｔ６５で、制御装置４は、時刻ｔ６４で検出した２次電流Ｉ２の最大値と、時刻ｔ６５で検出した２次電流Ｉ２の最小値との偏差に基づいて、２次電流Ｉ２の検出値の振幅ΔＩ２を算出し、振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも大きくなっているので、オンオフ周波数ｆｐｗｍを増加させている。なお、目標振幅ΔＩ２＿ｔｈは、上限閾値Ｉ２＿ｔｈＨと下限閾値Ｉ２＿ｔｈＬとの偏差に設定されている。 At time t65, the control device 4 determines the detected value of the secondary current I2 based on the deviation between the maximum value of the secondary current I2 detected at time t64 and the minimum value of the secondary current I2 detected at time t65. The amplitude ΔI2 is calculated, and since the amplitude ΔI2 is larger than the target amplitude ΔI2_th, the on / off frequency fpwm is increased. The target amplitude ΔI2_th is set to the deviation between the upper limit threshold value I2_thH and the lower limit threshold value I2_thL.
　その後、時刻ｔ６６までは２次電流Ｉ２の検出値の振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも大きいので、オンオフ周波数ｆｐｗｍが次第に増加されている。時刻ｔ６６で、２次電流Ｉ２の検出値の振幅ΔＩ２が、目標振幅ΔＩ２＿ｔｈよりも小さくなったので、オンオフ周波数ｆｐｗｍが減少され、その後は、オンオフ周波数ｆｐｗｍの増加と減少とが繰り返され、２次電流Ｉ２の検出値の振幅ΔＩ２は、目標振幅ΔＩ２＿ｔｈ付近に維持されている。 After that, until the time t66, the amplitude ΔI2 of the detected value of the secondary current I2 is larger than the target amplitude ΔI2_th, so the on / off frequency fpwm is gradually increased. At time t66, the amplitude ΔI2 of the detected value of the secondary current I2 became smaller than the target amplitude ΔI2_th, so that the on / off frequency fpwm was decreased, and then the on / off frequency fpwm was repeatedly increased and decreased to be secondary. The amplitude ΔI2 of the detected value of the current I2 is maintained near the target amplitude ΔI2_th.
　そして、時刻ｔ６７で、制御装置４は、第２のスイッチング素子２のオフ時期になったので、第２のスイッチング素子２を、オンからオフに切り替えると共に、パルス幅変調制御の実行判定情報Ｓ＿ＰＷＭをオフにし、パルス幅変調制御を停止し、第１のスイッチング素子１をオフにする。 Then, at time t67, the control device 4 has turned off the second switching element 2, so that the second switching element 2 is switched from on to off, and the execution determination information S_PWM of the pulse width modulation control is displayed. It is turned off, the pulse width modulation control is stopped, and the first switching element 1 is turned off.
　このように、第２のスイッチング素子２のオン期間中に、２次電流Ｉ２の検出値に応じて、第１のスイッチング素子１のパルス幅変調制御のオンオフ周波数を変化させることで、２次電流Ｉ２を、目標範囲内に精度よく維持することができ、着火性の向上及び電極消耗の増加抑制をバランスよく達成することができる。 In this way, during the ON period of the second switching element 2, the on / off frequency of the pulse width modulation control of the first switching element 1 is changed according to the detected value of the secondary current I2, so that the secondary current I2 can be accurately maintained within the target range, and improvement in ignitability and suppression of increase in electrode wear can be achieved in a well-balanced manner.
＜転用例＞
　上記の実施の形態３では、制御装置４は、常に、２次電流Ｉ２の検出値に応じて、パルス幅変調制御のオンオフ周波数を変化させる場合を例に説明した。しかし、制御装置４は、常に、２次電流Ｉ２の検出値を用いて制御する必要はなく、例えば、制御装置４は、１点火周期における動作を事前に決定しておき、次の点火周期においては、２次電流Ｉ２の検出値に関わらず、事前に決定した動作に従って、第１のスイッチング素子１をオンオフしてもよい。 <Example of diversion>
In the third embodiment, the case where the control device 4 always changes the on / off frequency of the pulse width modulation control according to the detected value of the secondary current I2 has been described as an example. However, the control device 4 does not always need to be controlled by using the detected value of the secondary current I2. For example, the control device 4 determines the operation in one ignition cycle in advance and in the next ignition cycle. May turn on / off the first switching element 1 according to a predetermined operation regardless of the detected value of the secondary current I2.
　本願は、様々な例示的な実施の形態及び実施例が記載されているが、１つ、または複数の実施の形態に記載された様々な特徴、態様、及び機能は特定の実施の形態の適用に限られるのではなく、単独で、または様々な組み合わせで実施の形態に適用可能である。従って、例示されていない無数の変形例が、本願明細書に開示される技術の範囲内において想定される。例えば、少なくとも１つの構成要素を変形する場合、追加する場合または省略する場合、さらには、少なくとも１つの構成要素を抽出し、他の実施の形態の構成要素と組み合わせる場合が含まれるものとする。 Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations. Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.
１　第１のスイッチング素子、２　第２のスイッチング素子、３　トランス、３ａ　第１の１次巻線、３ｂ　第２の１次巻線、３ｃ　２次巻線、４　制御装置、５　点火プラグ、６　直流電源、７　２次電流検出回路、８　電源電圧検出回路、１０　点火装置、Ｄｕｔｙ　オンデューティ、Ｉ１　１次電流、Ｉ１２　第２の１次電流、Ｉ２　２次電流、Ｉ２＿ｔｈＨ　上限閾値、Ｉ２＿ｔｈＬ　下限閾値、Ｓ＿ｓｗ１　第１のスイッチング素子の駆動信号、Ｓ＿ｓｗ２　第２のスイッチング素子の駆動信号、Ｖ１　電源電圧、ｆｐｗｍ　パルス幅変調制御のオンオフ周波数、ΔＩ２　二次電流の振幅、ΔＩ２＿ｔｈ　目標振幅 1 1st switching element, 2 2nd switching element, 3 transformer, 3a 1st primary winding, 3b 2nd primary winding, 3c secondary winding, 4 control device, 5 ignition plug, 6 DC power supply, 7 secondary current detection circuit, 8 power supply voltage detection circuit, 10 ignition device, Duty on duty, I1 primary current, I12 secondary primary current, I2 secondary current, I2_thH upper limit threshold, I2_thL lower limit threshold, S_sw1 drive signal of the first switching element, S_sw2 drive signal of the second switching element, V1 power supply voltage, fpwm pulse width modulation control on / off frequency, ΔI2 secondary current amplitude, ΔI2_th target amplitude

Claims (20)

  1. 　通電により通電磁束が生じる第１の１次巻線と、通電により前記第１の１次巻線の通電磁束とは逆方向の通電磁束が生じる第２の１次巻線と、前記第１の１次巻線及び前記第２の１次巻線に磁気結合され、点火プラグに放電エネルギを供給する２次巻線と、を有するトランスと、
    　直流電源から前記第１の１次巻線への通電をオンオフする第１のスイッチング素子と、
    　前記直流電源から前記第２の１次巻線への通電をオンオフする第２のスイッチング素子と、
    　前記第１のスイッチング素子をオンした後、前記第１のスイッチング素子をオフして、前記点火プラグに火花放電を発生させ、
    　前記火花放電の期間中に前記第２のスイッチング素子をオンし、
    　前記第２のスイッチング素子のオン期間中に、前記第１のスイッチング素子をオンオフする制御装置と、を備えた点火装置。     A first primary winding in which an energization magnetic flux is generated by energization, a second primary winding in which an energization magnetic flux in a direction opposite to the energization magnetic flux of the first primary winding is generated by energization, and the first winding. A transformer having a primary winding and a secondary winding magnetically coupled to the second primary winding to supply discharge energy to the ignition plug.
    A first switching element that turns on / off the energization from the DC power supply to the first primary winding, and
    A second switching element that turns on / off the energization from the DC power supply to the second primary winding, and
    After turning on the first switching element, the first switching element is turned off to generate a spark discharge in the spark plug.
    During the period of the spark discharge, the second switching element is turned on,
    An ignition device including a control device for turning on / off the first switching element during the on period of the second switching element.
  2. 　前記制御装置は、前記第２のスイッチング素子のオン期間中に、パルス幅変調制御により前記第１のスイッチング素子をオンオフする請求項１に記載の点火装置。 The ignition device according to claim 1, wherein the control device turns on / off the first switching element by pulse width modulation control during the on period of the second switching element.
  3. 　前記２次巻線に流れる２次電流を検出する２次電流検出回路を更に備え、
    　前記制御装置は、前記第２のスイッチング素子のオン期間中に、前記２次電流の検出値に基づいて、前記第１のスイッチング素子をオンオフする請求項１に記載の点火装置。     A secondary current detection circuit for detecting the secondary current flowing through the secondary winding is further provided.
    The ignition device according to claim 1, wherein the control device turns on / off the first switching element based on a detected value of the secondary current during the on period of the second switching element.
  4. 　前記制御装置は、前記第２のスイッチング素子のオン期間中に、前記２次電流の検出値が上限閾値よりも大きくなった時に、前記第１のスイッチング素子をオンする請求項３に記載の点火装置。 The ignition according to claim 3, wherein the control device turns on the first switching element when the detected value of the secondary current becomes larger than the upper limit threshold value during the on period of the second switching element. apparatus.
  5. 　前記制御装置は、前記２次電流の検出値が、前記上限閾値以下の値に設定された下限閾値よりも小さくなった時に、前記第１のスイッチング素子をオフする請求項４に記載の点火装置。 The ignition device according to claim 4, wherein the control device turns off the first switching element when the detected value of the secondary current becomes smaller than the lower limit threshold set to a value equal to or lower than the upper limit threshold value. ..
  6. 　前記制御装置は、前記火花放電の開始後の経過時間が増加するに従って、前記下限閾値を増加させる請求項５に記載の点火装置。 The ignition device according to claim 5, wherein the control device increases the lower limit threshold value as the elapsed time after the start of the spark discharge increases.
  7. 　前記制御装置は、内燃機関の運転状態と、前記第１のスイッチング素子及び前記第２のスイッチング素子の制御パラメータとの関係が予め設定された制御設定データを参照し、現在の前記内燃機関の運転状態に対応する前記制御パラメータを算出し、算出した前記制御パラメータに基づいて、前記火花放電の期間中に前記第２のスイッチング素子をオンすると共に、前記第２のスイッチング素子のオン期間中に前記第１のスイッチング素子をオンオフする請求項１又は２に記載の点火装置。 The control device refers to control setting data in which the relationship between the operating state of the internal combustion engine and the control parameters of the first switching element and the second switching element is preset, and refers to the current operation of the internal combustion engine. The control parameter corresponding to the state is calculated, and based on the calculated control parameter, the second switching element is turned on during the spark discharge period, and the second switching element is turned on during the on period of the second switching element. The ignition device according to claim 1 or 2, which turns on / off the first switching element.
  8. 　前記直流電源の電源電圧を検出する電源電圧検出回路を更に備え、
    　前記制御装置は、前記電源電圧及び内燃機関の運転状態と、前記第１のスイッチング素子及び前記第２のスイッチング素子の制御パラメータとの関係が予め設定された制御設定データを参照し、現在の前記電源電圧の検出値及び前記内燃機関の運転状態に対応する前記制御パラメータを算出し、算出した前記制御パラメータに基づいて、前記火花放電の期間中に前記第２のスイッチング素子をオンすると共に、前記第２のスイッチング素子のオン期間中に前記第１のスイッチング素子をオンオフする請求項１又は２に記載の点火装置。     A power supply voltage detection circuit for detecting the power supply voltage of the DC power supply is further provided.
    The control device refers to the control setting data in which the relationship between the power supply voltage and the operating state of the internal combustion engine and the control parameters of the first switching element and the second switching element is preset, and refers to the current control setting data. The control parameters corresponding to the detected value of the power supply voltage and the operating state of the internal combustion engine are calculated, and based on the calculated control parameters, the second switching element is turned on during the spark discharge period, and the second switching element is turned on. The ignition device according to claim 1 or 2, wherein the first switching element is turned on and off during the on period of the second switching element.
  9. 　前記内燃機関の運転状態は、内燃機関の気筒内の圧力、内燃機関の回転速度、内燃機関の圧縮比、空燃比、排気再循環率、内燃機関の始動後の経過時間、及び内燃機関の冷却水温度のいずれか一つ以上である請求項７又は８に記載の点火装置。 The operating states of the internal combustion engine include the pressure in the cylinder of the internal combustion engine, the rotation speed of the internal combustion engine, the compression ratio of the internal combustion engine, the air-fuel ratio, the exhaust gas recirculation rate, the elapsed time after the start of the internal combustion engine, and the cooling of the internal combustion engine. The ignition device according to claim 7 or 8, wherein the water temperature is any one or more.
  10. 　前記直流電源の電源電圧を検出する電源電圧検出回路を更に備え、
    　前記制御装置は、前記電源電圧の検出値に基づいて、前記第１のスイッチング素子及び前記第２のスイッチング素子の制御パラメータを変化させ、変化された前記制御パラメータに基づいて、前記火花放電の期間中に前記第２のスイッチング素子をオンすると共に、前記第２のスイッチング素子のオン期間中に前記第１のスイッチング素子をオンオフする請求項１又は２に記載の点火装置。     A power supply voltage detection circuit for detecting the power supply voltage of the DC power supply is further provided.
    The control device changes the control parameters of the first switching element and the second switching element based on the detected value of the power supply voltage, and the period of the spark discharge based on the changed control parameters. The ignition device according to claim 1 or 2, wherein the second switching element is turned on and the first switching element is turned on and off during the on period of the second switching element.
  11. 　前記２次巻線に流れる２次電流を検出する２次電流検出回路を更に備え、
    　前記制御装置は、前記第２のスイッチング素子のオン期間中に、前記２次電流の検出値が上限閾値よりも大きくなった時に、前記パルス幅変調制御を開始する請求項２に記載の点火装置。     A secondary current detection circuit for detecting the secondary current flowing through the secondary winding is further provided.
    The ignition device according to claim 2, wherein the control device starts the pulse width modulation control when the detected value of the secondary current becomes larger than the upper limit threshold value during the on period of the second switching element. ..
  12. 　前記２次巻線に流れる２次電流を検出する２次電流検出回路を更に備え、
    　前記制御装置は、前記２次電流の検出値が目標範囲内に収まるように、前記パルス幅変調制御のオンデューティを変化させる請求項２又は１１に記載の点火装置。     A secondary current detection circuit for detecting the secondary current flowing through the secondary winding is further provided.
    The ignition device according to claim 2 or 11, wherein the control device changes the on-duty of the pulse width modulation control so that the detected value of the secondary current falls within a target range.
  13. 　前記２次巻線に流れる２次電流を検出する２次電流検出回路を更に備え、
    　前記制御装置は、前記２次電流の検出値が上限閾値よりも大きくなった場合に、前記パルス幅変調制御のオンデューティを増加させる請求項２、１１、及び１２のいずれか一項に記載の点火装置。     A secondary current detection circuit for detecting the secondary current flowing through the secondary winding is further provided.
    The control device according to any one of claims 2, 11 and 12, which increases the on-duty of the pulse width modulation control when the detected value of the secondary current becomes larger than the upper limit threshold value. Ignition device.
  14. 　前記制御装置は、前記２次電流の検出値が、前記上限閾値以下に設定された下限閾値よりも小さくなった場合に、前記パルス幅変調制御のオンデューティを減少させる請求項１３に記載の点火装置。 The ignition according to claim 13, wherein the control device reduces the on-duty of the pulse width modulation control when the detected value of the secondary current becomes smaller than the lower limit threshold set below the upper limit threshold value. apparatus.
  15. 　前記２次巻線に流れる２次電流を検出する２次電流検出回路を更に備え、
    　前記制御装置は、前記２次電流の検出値が目標範囲内に収まるように、前記パルス幅変調制御のオンオフ周波数を変化させる請求項２、及び１１から１４のいずれか一項に記載の点火装置。     A secondary current detection circuit for detecting the secondary current flowing through the secondary winding is further provided.
    The ignition device according to any one of claims 2 and 11 to 14, wherein the control device changes the on / off frequency of the pulse width modulation control so that the detected value of the secondary current falls within the target range. ..
  16. 　前記２次巻線に流れる２次電流を検出する２次電流検出回路を更に備え、
    　前記制御装置は、前記２次電流の検出値の振幅が、目標振幅よりも大きくなった場合に、前記パルス幅変調制御のオンオフ周波数を増加させる請求項２、及び１１から１５のいずれか一項に記載の点火装置。     A secondary current detection circuit for detecting the secondary current flowing through the secondary winding is further provided.
    The control device increases the on / off frequency of the pulse width modulation control when the amplitude of the detected value of the secondary current becomes larger than the target amplitude, and any one of claims 2 and 11 to 15. The ignition device described in.
  17. 　前記制御装置は、前記２次電流の検出値の振幅が、前記目標振幅よりも小さくなった場合に、前記パルス幅変調制御のオンオフ周波数を減少させる請求項１６に記載の点火装置。 The ignition device according to claim 16, wherein the control device reduces the on / off frequency of the pulse width modulation control when the amplitude of the detected value of the secondary current becomes smaller than the target amplitude.
  18. 　前記第２の１次巻線の巻き数は、前記第１の１次巻線の巻き数よりも少ない請求項１から１７のいずれか一項に記載の点火装置。 The ignition device according to any one of claims 1 to 17, wherein the number of turns of the second primary winding is smaller than the number of turns of the first primary winding.
  19. 　前記第２のスイッチング素子の電流定格値は、前記第１のスイッチング素子の電流定格値よりも大きい請求項１から１８のいずれか一項に記載の点火装置。 The ignition device according to any one of claims 1 to 18, wherein the current rated value of the second switching element is larger than the current rated value of the first switching element.
  20. 　前記第１のスイッチング素子のスイッチング時間は、前記第２のスイッチング素子のスイッチング時間よりも短い請求項１から１９のいずれか一項に記載の点火装置。 The ignition device according to any one of claims 1 to 19, wherein the switching time of the first switching element is shorter than the switching time of the second switching element.
PCT/JP2019/019038 2019-05-14 2019-05-14 Ignition device WO2020230255A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021046857A (en) * 2019-09-12 2021-03-25 三菱電機株式会社 Igniter

Citations (3)

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Publication number Priority date Publication date Assignee Title
JPS6463658A (en) * 1987-09-03 1989-03-09 Nippon Denso Co Ignition device for internal combustion engine
JP2018178997A (en) * 2017-04-20 2018-11-15 株式会社デンソー Ignition system for internal combustion engine
WO2018229883A1 (en) * 2017-06-14 2018-12-20 日立オートモティブシステムズ阪神株式会社 Internal combustion engine ignition device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6463658A (en) * 1987-09-03 1989-03-09 Nippon Denso Co Ignition device for internal combustion engine
JP2018178997A (en) * 2017-04-20 2018-11-15 株式会社デンソー Ignition system for internal combustion engine
WO2018229883A1 (en) * 2017-06-14 2018-12-20 日立オートモティブシステムズ阪神株式会社 Internal combustion engine ignition device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021046857A (en) * 2019-09-12 2021-03-25 三菱電機株式会社 Igniter

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