WO2023223488A1 - Dispositif de commande de moteur à combustion interne et procédé de commande de moteur à combustion interne - Google Patents

Dispositif de commande de moteur à combustion interne et procédé de commande de moteur à combustion interne Download PDF

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Publication number
WO2023223488A1
WO2023223488A1 PCT/JP2022/020789 JP2022020789W WO2023223488A1 WO 2023223488 A1 WO2023223488 A1 WO 2023223488A1 JP 2022020789 W JP2022020789 W JP 2022020789W WO 2023223488 A1 WO2023223488 A1 WO 2023223488A1
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WIPO (PCT)
Prior art keywords
ignition
signal
temperature
internal combustion
combustion engine
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PCT/JP2022/020789
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English (en)
Japanese (ja)
Inventor
英一郎 大畠
健夫 高橋
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日立Astemo株式会社
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Priority to PCT/JP2022/020789 priority Critical patent/WO2023223488A1/fr
Publication of WO2023223488A1 publication Critical patent/WO2023223488A1/fr

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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 invention relates to an internal combustion engine control device and an internal combustion engine control method.
  • hydrocarbons hydrocarbons
  • the first is that due to the low in-cylinder temperature, unvaporized fuel is discharged as hydrocarbons without being oxidized (unburned).
  • the second problem is that due to the low in-cylinder temperature, less fuel is vaporized by the ignition timing, and the air-fuel ratio of the in-cylinder mixture increases (fuel becomes diluted). In this case, the required ignition energy increases, resulting in more ignition failures and extinguishing (misfires), which increases the amount of hydrocarbons.
  • control is performed to increase the fuel injection amount to be greater than the fuel injection amount after warm-up.
  • the amount of hydrocarbons generated during cold engine startup increases further.
  • an exhaust catalyst is provided in the exhaust pipe.
  • Exhaust catalysts use expensive precious metals such as platinum.
  • the manufacturing cost of the exhaust catalyst will increase significantly. Therefore, attempts have been made to reduce the amount of hydrocarbons generated by controlling the ignition device to reduce ignition failure and flame extinction in response to the increase in required ignition energy during cold engine starts.
  • Patent Document 1 discloses a control device for an internal combustion engine in which additional ignition is performed immediately after the normal ignition timing (main ignition) near compression top dead center in one combustion cycle of the internal combustion engine. has been done. According to this technique, ignition failure and flame extinction are reduced compared to the case where discharge is performed only once per combustion cycle with normal ignition timing. In addition, the amount of hydrocarbons generated during cold engine startup is reduced.
  • the ignition coil may be damaged by heat damage.
  • ignition failure occurs. Therefore, in the control device for an internal combustion engine described in Patent Document 1, ignition failure (extinction) is likely to occur under the multiple ignition permission condition, making it difficult to suppress the generation of hydrocarbons.
  • an object of the present invention to provide an internal combustion engine control device and an internal combustion engine control method that suppress the generation of hydrocarbons during cold starting of an internal combustion engine.
  • an internal combustion engine control device of the present invention controls an internal combustion engine that includes an ignition device that has a spark plug and an ignition coil that causes the spark plug to generate discharge.
  • the internal combustion engine control device includes a control section that outputs an output signal to the ignition device.
  • the output signals are a multiple ignition signal for preheating the spark plug, a frequency different from the multiple ignition signal, a main ignition signal for igniting the air-fuel mixture by discharging the spark plug, and a main ignition signal for precharging the ignition coil. and a pre-charging signal for performing.
  • the present invention it is possible to increase the charging energy to the ignition coil as much as possible to ensure appropriate implementation of ignition control during cold engine startup, and to suppress the generation of hydrocarbons from the internal combustion engine.
  • FIG. 1 is an overall configuration diagram showing an example of the basic configuration of an internal combustion engine according to an embodiment.
  • FIG. 2 is a partially enlarged view illustrating a spark plug according to an embodiment.
  • FIG. 1 is a functional block diagram illustrating a functional configuration of an internal combustion engine control device according to an embodiment.
  • FIG. 3 is a diagram illustrating the relationship between electrode temperature, minimum ignition energy, and air-fuel ratio.
  • FIG. 2 is a circuit diagram showing an example of an electric circuit including an ignition coil. This is an example of a discharge waveform of multiple ignitions. It is a figure explaining the relationship between the number of misfires and the amount of hydrocarbon emissions.
  • FIG. 3 is a diagram showing the relationship between the number of misfires and the environmental temperature.
  • FIG. 3 is a diagram showing the relationship between hydrocarbons and environmental temperature.
  • FIG. 3 is a diagram showing transitions when multiple ignition and main ignition are executed.
  • FIG. 2 is a conceptual diagram showing the relationship between the amount of heat generated and ignitability with respect to the frequency of an ignition signal.
  • FIG. 2 is a conceptual diagram showing the relationship between the transition time and the temperature of the ignition coil in the case of multiple ignition and the case of no multiple ignition. 2 is a timing chart showing changes in temperature and HC concentration of a conventional ignition coil.
  • FIG. 1 is a circuit diagram showing an example of an electric circuit including an ignition coil according to an embodiment.
  • 7 is a flowchart showing multiple ignition switching processing according to one embodiment. It is a flow chart which shows fuel injection amount switching processing concerning one embodiment.
  • 5 is a timing chart showing multiple ignition switching processing according to one embodiment. It is a flow chart which shows an example of fuel injection amount switching processing concerning one embodiment.
  • 2 is a timing chart showing the relationship between the operating state of an internal combustion engine installed in a general automobile and a multiple discharge permission period. It is a correlation graph showing the relationship between equivalence ratio and minimum ignition energy.
  • FIG. 1 is an overall configuration diagram showing an example of the basic configuration of an internal combustion engine according to an embodiment of the present invention.
  • the internal combustion engine 100 shown in FIG. 1 may have a single cylinder or multiple cylinders, in the embodiment, the internal combustion engine 100 having four cylinders will be described as an example.
  • air (intake) sucked in from the outside flows through an air cleaner 110, an intake pipe 111, and an intake manifold 112. Air that has passed through the intake manifold 112 flows into each cylinder 150 when the intake valve 151 opens. The amount of air flowing into each cylinder 150 is adjusted by the throttle valve 113. The amount of air adjusted by the throttle valve 113 is measured by a flow sensor 114.
  • the throttle valve 113 is provided with a throttle opening sensor 113a that detects the opening of the throttle. Opening information of the throttle valve 113 detected by the throttle opening sensor 113a is output to a control device (Electronic Control Unit: ECU) 1.
  • ECU Electronic Control Unit
  • an electronic throttle valve driven by an electric motor is used as the throttle valve 113.
  • the throttle valve according to the present invention may be of any other type as long as it can appropriately adjust the flow rate of air.
  • the temperature of the air flowing into each cylinder 150 is detected by the intake air temperature sensor 115.
  • crank angle sensor 121 is provided on the radially outer side of the ring gear 120 attached to the crankshaft 123.
  • Crank angle sensor 121 detects the rotation angle of crankshaft 123.
  • the crank angle sensor 121 detects the rotation angle of the crankshaft 123 every 10 degrees and every combustion cycle.
  • a water temperature sensor 122 is provided in the water jacket (not shown) of the cylinder head. Water temperature sensor 122 detects the temperature of the cooling water of internal combustion engine 100 .
  • the vehicle is provided with an accelerator position sensor 126 that detects the amount of displacement (depression amount) of the accelerator pedal 125.
  • the accelerator position sensor 126 detects the driver's requested torque.
  • the driver's requested torque detected by the accelerator position sensor 126 is output to the internal combustion engine control device 1, which will be described later.
  • Internal combustion engine control device 1 controls throttle valve 113 based on this requested torque.
  • the fuel stored in the fuel tank 130 is sucked and pressurized by the fuel pump 131.
  • the fuel sucked and pressurized by the fuel pump 131 is regulated to a predetermined pressure by a pressure regulator 132 provided in a fuel pipe 133.
  • the fuel adjusted to a predetermined pressure is injected into each cylinder 150 from a fuel injection device (injector) 134.
  • Excess fuel after the pressure is regulated by the pressure regulator 132 is returned to the fuel tank 130 via a return pipe (not shown).
  • Control of the fuel injection device 134 is performed based on a fuel injection pulse (control signal) from a fuel injection control section 82 (see FIG. 3) of the internal combustion engine control device 1, which will be described later.
  • a cylinder pressure sensor 140 (also referred to as a combustion pressure sensor) 140 is provided in the cylinder head (not shown) of the internal combustion engine 100.
  • the cylinder pressure sensor 140 is provided inside the cylinder 150 and detects the pressure (combustion pressure) inside the cylinder 150.
  • a piezoelectric pressure sensor or a gauge pressure sensor is applied as the cylinder pressure sensor 140. Thereby, the cylinder pressure inside the cylinder 150 can be detected over a wide temperature range.
  • An exhaust valve 152 and an exhaust manifold 160 are attached to each cylinder 150.
  • exhaust valve 152 opens, exhaust gas is discharged from the cylinder 150 to the exhaust manifold 160.
  • the exhaust manifold 160 discharges the gas (exhaust gas) after combustion to the outside of the cylinder 150.
  • a three-way catalyst 161 is provided on the exhaust side of the exhaust manifold 160. The three-way catalyst 161 purifies exhaust gas. Exhaust gas purified by the three-way catalyst 161 is discharged into the atmosphere.
  • An upstream air-fuel ratio sensor 162 is provided upstream of the three-way catalyst 161.
  • the upstream air-fuel ratio sensor 162 continuously (linearly) detects the air-fuel ratio of exhaust gas discharged from each cylinder 150.
  • the upstream air-fuel ratio sensor 162 of this embodiment is a linear air-fuel ratio sensor.
  • a downstream air-fuel ratio sensor 163 is provided downstream of the three-way catalyst 161.
  • the downstream air-fuel ratio sensor 163 outputs a detection signal that changes binary depending on whether the air-fuel ratio is richer or leaner than the stoichiometric air-fuel ratio.
  • the downstream air-fuel ratio sensor 163 of this embodiment is an O2 sensor.
  • a spark plug 200 is provided above each cylinder 150.
  • the spark plug 200 generates a spark by electric discharge (ignition), and the spark ignites the air-fuel mixture in the cylinder 150. This causes an explosion within the cylinder 150, and the piston 170 is pushed down. By pushing down the piston 170, the crankshaft 123 rotates.
  • An ignition coil 300 that generates electrical energy (voltage) to be supplied to the ignition plug 200 is connected to the ignition plug 200 .
  • Control device 1 detects the operating state of internal combustion engine 100 based on output signals from these various sensors. The control device 1 controls the amount of air sucked into the cylinder 150, the amount of fuel injected from the fuel injection device 134, the ignition timing of the spark plug 200, and the like.
  • FIG. 2 is a partially enlarged view illustrating the spark plug 200.
  • the spark plug 200 has a center electrode 210 and an outer electrode 220.
  • the center electrode 210 is supported by a plug base (not shown) via an insulator 230. Thereby, the center electrode 210 is insulated.
  • the outer electrode 220 is grounded.
  • a predetermined voltage for example, 20,000V to 40,000V
  • a discharge occurs between the center electrode 210 and the outer electrode 220. Then, the spark generated by the discharge ignites the air-fuel mixture (gas component) in the cylinder 150.
  • the voltage that causes dielectric breakdown of the gas components in the cylinder 150 and generates discharge depends on the state of the gas (air mixture in the cylinder) existing between the center electrode 210 and the outer electrode 220, and the state of the gas component in the cylinder 150. It varies depending on the cylinder pressure. The voltage at which this discharge occurs is called the dielectric breakdown voltage.
  • Discharge control (ignition control) of the spark plug 200 is performed by an ignition control section 83 (see FIG. 3) of the control device 1, which will be described later.
  • the control device 1 includes an analog input section 10, a digital input section 20, an A/D (Analog/Digital) conversion section 30, a RAM (Random Access Memory) 40, and an MPU (Micro- It has a ROM (Read Only Memory) 60, an I/O (Input/Output) port 70, and an output circuit 80.
  • the analog input section 10 receives signals from various sensors such as a throttle opening sensor 113a, a flow rate sensor 114, an accelerator position sensor 126, an upstream air-fuel ratio sensor 162, a downstream air-fuel ratio sensor 163, a cylinder pressure sensor 140, and a water temperature sensor 122. An analog output signal is input.
  • sensors such as a throttle opening sensor 113a, a flow rate sensor 114, an accelerator position sensor 126, an upstream air-fuel ratio sensor 162, a downstream air-fuel ratio sensor 163, a cylinder pressure sensor 140, and a water temperature sensor 122.
  • An analog output signal is input.
  • An A/D conversion section 30 is connected to the analog input section 10. Analog output signals from various sensors input to the analog input section 10 are converted into digital signals by the A/D conversion section 30. The digital signal converted by the A/D converter 30 is then stored in the RAM 40.
  • a digital output signal from the crank angle sensor 121 is input to the digital input section 20.
  • An I/O port 70 is connected to the digital input section 20.
  • the digital output signal input to the digital input section 20 is stored in the RAM 40 via the I/O port 70.
  • Each output signal stored in the RAM 40 is processed by the MPU 50.
  • the MPU 50 executes a control program (not shown) stored in the ROM 60 to process the output signal stored in the RAM 40 according to the control program.
  • the MPU 50 calculates a control value that defines the operating amount of each actuator (for example, the throttle valve 113, the fuel pump 131, the spark plug 200, etc.) that drives the internal combustion engine 100 according to the control program, and temporarily stores the control value in the RAM 40. remember exactly.
  • the control value that defines the amount of operation of the actuator stored in the RAM 40 is output to the output circuit 80 via the I/O port 70.
  • the output circuit 80 is provided with functions such as an overall control section 81, a fuel injection control section 82, and an ignition control section 83 (see FIG. 3).
  • the overall control unit 81 performs overall control of the internal combustion engine based on output signals from various sensors (for example, the cylinder pressure sensor 140).
  • the fuel injection control unit 82 controls driving of a plunger rod (not shown) of the fuel injection device 134.
  • the ignition control section 83 controls the voltage applied to the spark plug 200.
  • FIG. 3 is a functional block diagram illustrating the functional configuration of the control device 1. As shown in FIG. 3,
  • Each function of the control device 1 is realized as various functions in the output circuit 80 by the MPU 50 executing a control program stored in the ROM 60.
  • Various functions in the output circuit 80 include, for example, control of the fuel injection device 134 by the fuel injection control section 82 and control of the ignition coil 300 by the ignition control section 83.
  • the output circuit 80 of the control device 1 includes an overall control section 81, a fuel injection control section 82, and an ignition control section 83.
  • the overall control unit 81 receives requested torque (acceleration information S1) from the accelerator position sensor 126 and cylinder pressure information S2 from the cylinder pressure sensor 140, which are stored in the RAM 40.
  • the overall control unit 81 controls the overall control of the fuel injection control unit 82 and the ignition control unit 83 based on the required torque (acceleration information S1) from the accelerator position sensor 126 and the cylinder pressure information S2 from the cylinder pressure sensor 140. control.
  • the fuel injection control unit 82 includes an angle information generation unit 85 that measures the crank angle of the crankshaft 123, and an angle information generation unit 85 that measures the crank angle of the crankshaft 123. It is connected to a cylinder determining section 84 that determines whether the engine is in a compression stroke (compression, intake, or compression stroke), and a rotation speed information generating section 86 that measures the engine speed.
  • the fuel injection control section 82 receives cylinder discrimination information S3 from the cylinder discrimination section 84, crank angle information S4 from the angle information generation section 85, and engine rotation speed information S5 from the rotation speed information generation section 86.
  • the fuel injection control unit 82 also includes an intake air amount measuring unit 87 that measures the amount of air taken into the cylinder 150, a load information generating unit 88 that measures the engine load, and a temperature of engine cooling water. It is connected to the water temperature measuring section 89.
  • the fuel injection control section 82 receives intake air amount information S6 from the intake air amount measurement section 87, engine load information S7 from the load information generation section 88, and cooling water temperature information S8 from the water temperature measurement section 89.
  • the fuel injection control unit 82 calculates the injection amount and injection time of the fuel injected from the fuel injection device 134 based on the received information. The fuel injection control unit 82 then transmits the fuel injection pulse S9 generated based on the calculated fuel injection amount and injection time to the fuel injection device 134.
  • the ignition control section 83 is connected to the overall control section 81, a cylinder discrimination section 84, an angle information generation section 85, a rotation speed information generation section 86, a load information generation section 88, and a water temperature measurement section 89. We accept information from these sources.
  • the ignition control unit 83 determines the amount of current to be applied to the primary coil 310 (see FIG. 5) of the ignition coil 300, the energization start time (energization angle), and the amount of current to be applied to the primary coil 310 of the ignition coil 300 (see FIG. 5). Calculate the time to cut off the applied current (ignition time).
  • the ignition control unit 83 outputs an ignition signal SA to the primary coil 310 of the ignition coil 300 based on the calculated energization amount, energization start time, and ignition time, thereby controlling the discharge by the ignition plug 200 ( ignition control).
  • FIG. 4 is a diagram illustrating the relationship between electrode temperature, minimum ignition energy, and air-fuel ratio.
  • FIG. 4 shows the air-fuel ratio values corresponding to the minimum ignition energy values.
  • the vertical direction indicates a voltage scale value corresponding to the minimum ignition energy of the air-fuel mixture
  • the left-right direction in FIG. 4 indicates an air-fuel ratio scale value corresponding to the air-fuel ratio of the air-fuel mixture.
  • the air-fuel ratio P1 shown in FIG. 4 is an air-fuel ratio value corresponding to a predetermined value of the minimum ignition energy that can ignite the air-fuel mixture when the electrode temperature of the spark plug is low (for example, -7 degC).
  • the air-fuel ratio P2 is an air-fuel ratio value corresponding to a predetermined value of the minimum ignition energy that can ignite the air-fuel mixture when the electrode temperature of the spark plug is high (for example, 25 degC).
  • a value equivalent to the minimum ignition energy corresponding to the air-fuel ratio P2 when the spark plug electrode temperature is high is obtained when the spark plug electrode temperature is low.
  • the discharge (ignition) from the spark plug 200 cannot exceed the minimum ignition energy unless the air-fuel ratio is set to the air-fuel ratio P1, which is smaller (fuel richer) than the air-fuel ratio P2. Therefore, conventionally, as a setting with a safety margin that does not cause problems such as misfires in the internal combustion engine 100, a rich air-fuel ratio (P1), which assumes that the temperature of the electrode of the spark plug 200 is always low, is used for fuel injection. It was set in the control unit 82. As a result, in the internal combustion engine 100, as the ratio of fuel in the air-fuel mixture increased, more hydrocarbons (HC) were generated during combustion.
  • the higher the temperature of the electrode of the spark plug 200 at the time of cold start (see the thick arrow in FIG. 4), the lower the minimum ignition energy for igniting the air-fuel mixture. Therefore, even if the air-fuel ratio is increased (the fuel is made thinner), the discharge (ignition) from the spark plug exceeds the minimum ignition energy, making it possible to ignite the air-fuel mixture. As a result, generation of hydrocarbons (HC) in internal combustion engine 100 can be reduced. Therefore, in the internal combustion engine 100, as will be described later, the temperature of the electrode of the spark plug 200 during cold start is raised before discharge (ignition). This makes it possible to increase the air-fuel ratio during cold engine startup and suppress the generation of hydrocarbons (HC).
  • FIG. 5 is a diagram illustrating an electric circuit including an ignition coil.
  • the electric circuit 500 shown in FIG. 5 includes an ignition coil 300.
  • the ignition coil 300 includes a primary coil 310 wound with a predetermined number of turns, and a secondary coil 320 wound with a larger number of turns than the primary coil 310.
  • One end of the primary coil 310 is connected to a DC power source 330.
  • a predetermined voltage for example, 12V
  • the other end of the primary coil 310 is connected to a drain (D) terminal of an igniter (energization control circuit) 340 and grounded via the igniter 340.
  • a transistor, a field effect transistor (FET), or the like is used for the igniter 340.
  • the gate (G) terminal of the igniter 340 is connected to the ignition control section 83 via the temperature switch section 350.
  • the temperature switch section 350 is installed for the purpose of preventing damage to the ignition coil 300 due to overheating.
  • the temperature switch section 350 includes a temperature detection section 351.
  • Temperature detection section 351 detects the temperature of ignition coil 300 via igniter 340.
  • the temperature switch section 350 cuts off the ignition signal SA output from the ignition control section 83 to the igniter 340 when the temperature detected by the temperature detection section 351 becomes equal to or higher than a predetermined threshold value A (first temperature).
  • the ignition signal SA output from the ignition control unit 83 when the temperature detected by the temperature detection unit 351 is less than the first temperature is input to the gate (G) terminal of the igniter 340.
  • the ignition signal SA When the ignition signal SA is input to the gate (G) terminal of the igniter 340, the drain (D) terminal and the source (S) terminal of the igniter 340 become energized, and the drain (D) terminal and the source (S) terminal become energized. A current flows through. As a result, the ignition signal SA is output from the ignition control section 83 to the primary coil 310 of the ignition coil 300 via the igniter 340. As a result, current flows through the primary coil 310 and electric power (electrical energy) is accumulated.
  • the high voltage generated in the secondary coil 320 is applied to the center electrode 210 (see FIG. 2) of the spark plug 200. This generates a potential difference between the center electrode 210 and the outer electrode 220 of the spark plug 200.
  • Vm dielectric breakdown voltage of the surrounding gas
  • the gas component undergoes dielectric breakdown and the center electrode 210 and the outer electrode 220 A discharge occurs between the As a result, the fuel (air mixture) is ignited (ignition).
  • An electric circuit 500 having a spark plug 200 and an ignition coil 300 corresponds to an ignition device according to the present invention.
  • the discharge path generated between the center electrode 210 and the outer electrode 220 reaches a high temperature of several thousand degrees Celsius. Since the discharge path is in contact with the surrounding gas and the electrodes 210 and 220, the exothermic energy of the discharge is distributed to the surrounding gas and the electrodes 210 and 220. The exothermic energy distributed to the surrounding gas heats (preheats) the surrounding gas and the electrodes 210 and 220 to promote ignition.
  • FIG. 6 is an example of a discharge waveform of multiple ignitions.
  • multiple ignitions are performed by adding multiple discharges by repeating ON and OFF of the ignition signal.
  • the temperature of the electrodes 210 and 220 of the spark plug 200 can be increased before the discharge (ignition) that preheats the electrodes of the spark plug 200.
  • Multiple ignition by this additional discharge can be performed at a timing that does not overlap with the ignition timing of the main ignition. That is, multiple ignition by additional discharge can be performed at least during the period from the ignition (start of discharge) of the main ignition until the start of fuel injection (the period from the expansion stroke to the intake stroke in the embodiment of FIG. 6).
  • FIG. 7 is a diagram illustrating the relationship between the number of misfires counted in 15 seconds and the amount of hydrocarbon discharged (integrated mass) in the same 15 seconds.
  • FIG. 8 is a diagram showing the relationship between the number of misfires counted during a period of 60 seconds from the start of the internal combustion engine and the multiple ignition period (heating period) due to additional discharge performed within the period.
  • FIG. 9 is a diagram showing the relationship between the cumulative mass of hydrocarbons discharged from the start of the internal combustion engine until 60 seconds have elapsed and the heating period.
  • misfire occurs when a flame kernel generated by ignition is unable to grow and is extinguished. In order to grow the flame kernel and suppress the generation of hydrocarbons (HC), it is necessary to suppress misfires.
  • HC hydrocarbons
  • the ignition device performs multiple ignitions to preheat the electrodes 210 and 220 of the spark plug 200, the temperature difference between the discharge path and the flame kernel and the electrodes 210 and 220 will be reduced. As a result, the amount of heat transmitted from the discharge path or flame kernel to the electrodes 210, 220 can be suppressed.
  • the heating period of the electrodes 210 and 220 there is an inversely proportional relationship between the heating period of the electrodes 210 and 220 and the number of misfires, and the longer the heating period, the more the number of misfires can be reduced.
  • the temperature of the electrodes 210 and 220 changes depending on the environmental temperature. Therefore, the higher the environmental temperature, the higher the temperature of the electrodes 210 and 220 of the spark plug 200. Therefore, as shown in FIG. 8, the number of misfires when the environmental temperature is 80 degC is smaller than the number of misfires when the environmental temperature is 20 degC.
  • the broken line in FIG. 9 the longer the heating period and the higher the environmental temperature, the more the amount of hydrocarbon emissions can be reduced.
  • FIG. 10 is a diagram showing the transition when performing multiple ignition and main ignition.
  • FIG. 11 is a conceptual diagram showing the relationship between the calorific value and ignitability with respect to the frequency of the ignition signal.
  • FIG. 12 is a conceptual diagram showing the relationship between the transition time and the temperature of the ignition coil in the case of multiple ignition and the case of no multiple ignition.
  • FIG. 13 is a timing chart showing changes in temperature and HC concentration of a conventional ignition coil.
  • the purpose of the multiple ignition performed in this embodiment is to preheat the electrode of the spark plug 200 before main ignition. Therefore, multiple ignitions are performed before the main ignition. Moreover, multiple ignition can also be called preheating ignition. As shown in FIG. 10, the ignition performance of the main ignition can be improved by increasing the ignition energy per discharge. On the other hand, preheating by multiple ignitions can improve the amount of electrode heating by increasing the discharge duration per unit time.
  • the main ignition is set so that the ignition energy per discharge is equal to or higher than the above-mentioned dielectric breakdown voltage Vm. Thereby, a discharge is generated between the center electrode 210 and the outer electrode 220, and the air-fuel mixture is ignited (flame kernel formation).
  • the multiple ignition (preheat ignition) performed in this embodiment electric discharge is generated between the center electrode 210 and the outer electrode 220 before the main ignition, and the electrodes 210 and 220 of the spark plug 200 can be preheated. It is a purpose. Therefore, multiple ignition (preheat ignition) is performed at a time point before main ignition in time series.
  • ignition In multiple ignition (preheat ignition), ignition (discharge) is repeated multiple times to increase the power conversion amount of the ignition coil 300 and increase the discharge duration per unit time. Thereby, the amount of heating (preheating) of the electrodes 210 and 220 can be increased. Therefore, in multiple ignition (preheat ignition), it is necessary to set the switching frequency of the ignition signal SA higher than that in main ignition. That is, the ignition control unit 83 (see FIG. 3) outputs a low-frequency main ignition signal for performing main ignition and a high-frequency multiple ignition signal for performing multiple ignition (preheat ignition). Thus, as shown in FIG. 11, when the frequency of the ignition signal SA is increased, the amount of heat generated by the electrodes 210 and 220 of the spark plug 200 increases. As a result, the ignitability of the spark plug 200 is improved.
  • FIG. 14 is a circuit diagram showing an example of an electric circuit including an ignition coil according to the present invention.
  • an electric circuit 501 includes an ignition coil 300.
  • the ignition coil 300 includes a primary coil 310 wound with a predetermined number of turns, and a secondary coil 320 wound with a larger number of turns than the primary coil 310.
  • One end of the primary coil 310 is connected to a DC power source 330.
  • a predetermined voltage for example, 12V
  • the other end of the primary coil 310 is connected to a drain (D) terminal of an igniter (energization control circuit) 340 and grounded via the igniter 340.
  • a transistor, a field effect transistor (FET), or the like is used for the igniter 340.
  • the gate (G) terminal of the igniter 340 is connected to the ignition control section 83 via the temperature switch section 360 or the temperature switch section 360 and the filter section 370.
  • Filter section 370 is, for example, a low-pass filter. Filter section 370 passes the main ignition signal having a low frequency. The filter section 370 then blocks the multiple ignition signal, which is a high frequency signal.
  • the temperature switch section 360 is installed for the purpose of adjusting the temperature of the ignition coil 300.
  • the temperature switch section 360 includes a temperature detection section 351.
  • the temperature switch unit 360 switches the connection destination according to the coil temperature range (low temperature range, medium temperature range, high temperature range) detected by the temperature detection unit 351.
  • the medium temperature range is a region above the threshold A (first temperature) described above and below the predetermined threshold B (second temperature).
  • the temperature switch section 360 connects the ignition control section 83 and the igniter 340 via the filter section 370.
  • the high frequency multiple ignition signal output from the ignition control section 83 is blocked by the filter section 370.
  • the low-frequency main ignition signal output from the ignition control section 83 passes through the filter section 370 and is transmitted to the igniter 340.
  • the high temperature range is a range above the threshold B (second temperature) described above and below the upper limit of the design rated temperature of the ignition coil 300.
  • the temperature switch section 360 disconnects the ignition control section 83 and the igniter 340. As a result, the multiple ignition signal and the main ignition signal output from the ignition control section 83 are not transmitted to the igniter 340.
  • the low temperature region is a region below the threshold value A (first temperature) described above.
  • the temperature switch section 360 directly connects the ignition control section 83 and the igniter 340. Thereby, the multiple ignition signal and the main ignition signal output from the ignition control section 83 are transmitted to the igniter 340.
  • the coil temperature in the low temperature range, the coil temperature is lower than in the medium temperature range or the high temperature range, and the temperature difference (temperature margin) from the upper limit of the design rated temperature of the ignition coil 300 is large. Therefore, in addition to main ignition for igniting the air-fuel mixture, multiple ignition (preheating ignition) in which the ignition coil 300 generates a large amount of heat can be performed. Moreover, in the present embodiment, the temperature detection unit 351 accurately detects the coil temperature and performs multiple ignition (preheat ignition) until the coil temperature reaches a medium temperature range equal to or higher than the threshold value B (second temperature).
  • the temperature margin with respect to the upper limit of the rated temperature can be minimized, and the period for performing multiple ignitions can be extended, rather than performing multiple ignitions (preheating ignition) in the estimated low temperature range without providing the temperature detection unit 351. It can be set as long as possible.
  • the ignition signal SA main ignition signal only, or main ignition signal and multiple signals
  • the main ignition signal is input to the gate (G) terminal of the igniter 340 via the temperature switch section 360.
  • the ignition signal SA is input to the gate (G) terminal of the igniter 340, the drain (D) terminal and the source (S) terminal of the igniter 340 become energized, and the drain (D) terminal and the source (S) terminal become energized.
  • the ignition signal SA is output from the ignition control section 83 to the primary coil 310 of the ignition coil 300 via the igniter 340.
  • electric power electric energy
  • the high voltage generated in the secondary coil 320 is applied to the center electrode 210 (see FIG. 2) of the spark plug 200. This generates a potential difference between the center electrode 210 and the outer electrode 220 of the spark plug 200.
  • Vm dielectric breakdown voltage of the surrounding gas
  • the gas component undergoes dielectric breakdown and the center electrode 210 and the outer electrode 220 A discharge occurs between the As a result, the fuel (air mixture) is ignited (ignition).
  • An electric circuit 500 having a spark plug 200 and an ignition coil 300 corresponds to an ignition device according to the present invention.
  • the ignition control section 83 has an energization control circuit 831 and an output monitor circuit 832.
  • the energization control circuit 831 controls the output of the ignition signal SA.
  • the output monitor circuit 832 has a return detection function that detects the ignition signal SA output from the energization control circuit 831 as a return signal, and transmits the detection result of the return signal to the energization control circuit 831.
  • the energization control circuit 831 transmits the output state of the ignition signal SA and the detection result of the return signal corresponding to the ignition signal SA to the overall control unit 81 (see FIG. 3).
  • the overall control unit 81 compares the output state of the ignition signal SA and the detection result of the return signal, and if the states of the ignition signal SA and the return signal are different, the filter unit 370 outputs a multiple ignition signal or an overheat detection signal to be described later. is determined to have been blocked. Furthermore, when the ignition signal SA and the return signal are the same, the overall control section 81 determines that the multiple ignition signal and the overheat detection signal are not blocked in the filter section 370.
  • the amount of heat generated by the ignition coil 300 is larger than that in normal ignition, so the actual temperature of the ignition coil 300 reaches the intermediate temperature range in a relatively short time. Then, when the actual temperature of the ignition coil 300 reaches the intermediate temperature range, the temperature switch section 360 cuts off the transmission of the multiple ignition signal to the igniter 340.
  • the filter section 370 determines whether the main ignition signal or the multiple ignition signal is blocked. Furthermore, based on the determination result, the actual temperature of the ignition coil 300 reaches the medium temperature range and only the multiple ignition signal is cut off, or the actual temperature of the ignition coil 300 returns to the low temperature range and the main ignition is started. The point in time when the signal and the multiple ignition signal are transmitted to the igniter 340 again is detected. Then, the coil temperature of the temperature detection unit 351 is calibrated by assuming that the coil temperature at the time of detection is the threshold value A (first temperature).
  • the ignition coil 300 is cooled due to the temperature difference with its surroundings (see FIG. 13).
  • the temperature detected by the temperature detection section 351 returns to the low temperature range.
  • the temperature switch section 360 selects a path in which the ignition signal SA is transmitted to the igniter 340 without passing through the filter section 370. Thereby, the main ignition signal and the multiple ignition signal are transmitted to the igniter 340 again. Therefore, multiple ignitions can be repeated while suppressing misfires, and generation of hydrocarbons can be suppressed.
  • T the fuel injection amount after warming up the internal combustion engine, which is not at the time of cold start.
  • T the fuel injection amount after warming up the internal combustion engine, which is not at the time of cold start.
  • the amount of fuel vaporized by the main ignition timing decreases due to the low in-cylinder temperature, so the amount of fuel involved in combustion after ignition decreases.
  • the fuel injection amount is increased from the injection amount T after warm-up at the time of cold engine startup. Assuming that this amount of increase is a, the fuel injection amount at the time of cold engine start is T+a.
  • the amount of fuel that is vaporized by the main ignition timing and participates in post-ignition combustion is substantially increased. If the contribution of this multiple ignition (preheating ignition) is b1, the fuel injection amount when multiple ignition is executed is T+a ⁇ b1.
  • the temperature of the electrodes 210 and 220 of the spark plug 200 may be inferred based on the coil temperature detected by the above-mentioned temperature detection unit 351 or the operating state of the internal combustion engine 100 such as water temperature or intake air temperature. be.
  • the temperature of the electrodes 210, 220 at the time when the coil temperature reaches the intermediate temperature range and multiple ignition is interrupted is set based on the above-mentioned threshold value A (first temperature). Then, it is inferred that the temperatures of the electrodes 210 and 220 are sequentially lowered based on the elapse of time after the multiple ignition was interrupted or the elapse of the combustion cycle (such as the number of times main ignition was performed).
  • FIG. 15 is a flowchart illustrating an example of multiple ignition switching processing.
  • the temperature detection unit 351 acquires the coil temperature of the ignition coil 300. Then, the temperature switch section 360 determines whether the coil temperature detected by the temperature detection section 351 is equal to or higher than a predetermined threshold value B (second temperature) (S110).
  • step S110 when it is determined that the coil temperature is equal to or higher than the predetermined threshold B (YES in S110), the temperature switch section 360 selects a path (circuit) that completely cuts off the ignition signal SA ( S120). As a result, the ignition signal SA output from the ignition control section 83 is not transmitted to the igniter 340, and ignition (ignition) by the spark plug 200 is stopped.
  • the ignition device electrical circuit 501 moves the process to step S110.
  • step S110 when it is determined in step S110 that the coil temperature is not equal to or higher than the predetermined threshold B (if NO in S110), the temperature switch unit 360 sets the coil temperature to a predetermined threshold A (first temperature). It is determined whether or not it is the above (S130).
  • step S130 when it is determined that the coil temperature is equal to or higher than the predetermined threshold value A (YES in S130), the temperature switch section 360 selects a path for the ignition signal SA to pass through the filter section 370 ( S140). As a result, multiple ignition signals in the ignition signal SA are blocked by the filter section 370, and only the main ignition signal is transmitted to the igniter 340. As a result, in the spark plug 200, multiple ignition for the purpose of preheating is not performed, and only main ignition is performed. After the process in step S140, the ignition device moves the process to step S110.
  • step S130 when it is determined in step S130 that the coil temperature is not equal to or higher than the predetermined threshold A (if NO in S130), the temperature switch section 360 switches the ignition signal SA to the igniter 340 without passing through the filter section 370. A route to be transmitted to is selected (S150). Thereby, the multiple ignition signal and the main ignition signal in the ignition signal SA are transmitted to the igniter 340. As a result, multiple ignition for the purpose of preheating and main ignition are performed in the ignition plug 200. After the process in step S150, the ignition device moves the process to step S110.
  • FIG. 16 is a flowchart illustrating an example of fuel injection amount switching processing.
  • the overall control unit 81 acquires the time that has passed since the start of the internal combustion engine. Then, the overall control unit 81 determines whether the time that has passed from the start to the present is within a predetermined value (S210).
  • the predetermined value corresponds to the period until the warm-up described above is completed.
  • step S210 When it is determined in step S210 that the time that has passed from the start to the present is not within a predetermined value (NO in S210), the overall control unit 81 ends the fuel injection amount switching process (S220). .
  • step S210 when it is determined in step S210 that the time that has passed from the start to the present is within a predetermined value (YES in S210), the overall control unit 81 sends an ignition signal including a multiple ignition signal. SA is output (S230). Next, the overall control unit 81 determines whether the ignition signal SA and the return signal obtained from the output monitor circuit 832 are different (S240).
  • step S240 when it is determined that the ignition signal SA and the return signal are different (YES in S240), the overall control unit 81 sets the fuel injection amount to the first fuel injection amount (S250).
  • the overall control unit 81 determines that the filter unit 370 has blocked the multiple ignition signal when the ignition signal SA and the return signal are different.
  • the temperature of the ignition coil 300 is equal to or higher than the threshold value A (first temperature).
  • the overall control unit 81 moves the process to step S210.
  • step S240 when it is determined in step S240 that the ignition signal SA and the return signal match (if NO in S240), the overall control unit 81 sets the fuel injection amount to the second fuel injection amount (S260). The overall control unit 81 determines that the multiple ignition signal has been transmitted to the igniter 340 when the ignition signal SA and the return signal match. After the process in step S260, the overall control unit 81 moves the process to step S210.
  • the first fuel injection amount is the fuel injection amount when the multiple ignition signal is cut off during cold start.
  • the first fuel injection amount corresponds to T+a described above.
  • the second fuel injection amount is the fuel injection amount when the multiple ignition signal is transmitted to the igniter 340 during cold engine startup.
  • FIG. 17 is a timing chart showing multiple ignition switching processing.
  • a method is needed to efficiently raise the temperature of the electrode without unnecessarily increasing the ignition energy due to multiple ignitions.
  • the duration of discharge per unit time can be extended, and in turn, the duration of multiple ignitions can be extended.
  • the time for the electrodes 210, 220 to cool down between the discharges of the main ignition can be shortened as much as possible (see the first stage of FIG. 17). As a result, the heating efficiency due to multiple ignitions can be improved, and the temperature of the electrode after the discharge period can be efficiently raised.
  • a typical passive ignition coil has the ability to store a certain amount of charge. Therefore, the amount of charge increases until a certain charging time. Then, as the amount of charge increases, the output voltage and output current during discharging increase, and the electrodes 210 and 220 are heated strongly. Therefore, by outputting a low frequency precharge pulse (precharge signal) with sufficient precharging immediately before outputting a high frequency multiple discharge pulse (multiple ignition signal) for performing multiple ignitions, the above-mentioned As shown in FIG. 17, the temperature of the electrodes 210 and 220 can be further increased while making the interval between multiple ignitions as high as possible (see the second row of FIG. 17). That is, the precharge pulse is an energizing waveform that has a lower frequency than the multiple discharge pulse and has an output period such that the capacitive discharge of the ignition coil is reliably activated.
  • the electric circuit 501 including the ignition coil 300 described above cuts only the high frequency component of the ignition signal SA when the temperature of the ignition coil 300 is equal to or higher than the threshold value A (first temperature). Therefore, the electric circuit 501 continues the low-frequency precharge signal even when the temperature of the ignition coil 300 is equal to or higher than the threshold value A (first temperature). As a result, high-frequency multiple ignition cannot be performed (the multiple ignition signal is cut), and the heating efficiency of the electrodes 210 and 220 decreases.
  • the control device (ECU) 1 has a return detection function (output monitor circuit 832) that performs self-diagnosis of the ignition signal SA output to the ignition coil 300.
  • This return detection function allows the control device 1 to detect the cutting of high frequency components performed by the electric circuit 501 in the high temperature range or medium temperature range of the ignition coil 300.
  • the control device 1 recognizes that the temperature state of the ignition coil 300 is equal to or higher than the threshold value A (first temperature)
  • the control device 1 recognizes that the temperature state of the ignition coil 300 is equal to or higher than the threshold value A (first temperature).
  • the output of the discharge pulse is cut off from the ignition signal SA. That is, the control device 1 outputs only the main ignition signal when the coil temperature is equal to or higher than the threshold value A (first temperature). As a result, the amount of heat generated by the ignition coil 300 can be suppressed.
  • control device 1 cannot detect the cutting of high frequency components by the electric circuit 501 in a state where only the main ignition signal is output. Therefore, even if the temperature state of the ignition coil 300, which has once increased, converges to below the threshold value A (first temperature), the control device 1 may not be able to resume outputting the multiple ignition signal. Therefore, the control device 1 outputs an overheat detection pulse (overheat detection signal) after the coil temperature becomes equal to or higher than the threshold value A (first temperature) and transitions to a state where only the main ignition signal is output (see FIG. 17). (See third row).
  • overheat detection pulse overheat detection signal
  • the overheat detection pulse is at least one high frequency pulse (single pulse). This can reduce wasteful charging and wasteful signal output operations. Moreover, the frequency of the overheat detection pulse is within a frequency band that exceeds the rated frequency at which the filter section 370 of the electric circuit 501 blocks the ignition signal SA, and the return detection function (output monitor circuit 832) of the control device 1 allows the ignition signal to be ignited.
  • the return signal of signal SA is set within a detectable range. As a result, the overheat detection pulse is cut by the filter section 370 in the medium temperature range, and is not cut by the filter section 370 in the low temperature range. Therefore, the control device 1 can correctly recognize the temperature state of the ignition coil 300 by using the return detection function to detect whether or not the overheating detection pulse is cut by the filter section 370 (the 4 stages shown in FIG. 17). (see item).
  • the control device 1 When the control device 1 recognizes that the coil temperature is less than the threshold value A (first temperature), it resumes outputting the ignition signal SA including the precharge signal and the multiple ignition signal (see the fifth stage in FIG. 17). . After restarting the output of the precharge signal and the multiple ignition signal, the output of the overheat detection pulse is stopped (see the fifth stage in FIG. 17). Thereby, the amount of heat generated by the ignition coil 300 can be suppressed while reducing the calculation load on the control device 1 and the load on the ignition control section 83.
  • the threshold value A first temperature
  • the phase of the overheating detection pulse is set at a timing that is later than the previous main ignition signal but before the next precharge signal and that allows the time required for switching the ignition signal of the control device 1 to be secured.
  • the time required to switch the ignition signal is the time required to output the overheat detection pulse of the control device 1, detect the return signal of the overheat detection pulse, and determine whether or not precharging is possible. is the sum of Thereby, the control device 1 can switch the output of the precharge pulse and the multiple discharge pulse within a cycle.
  • the phase of the overheating detection pulse is preferably set as late as possible within the time period necessary for switching the ignition signal described above.
  • the latest (recent) temperature status of the ignition coil 300 according to the previous main ignition signal is reflected in the return signal of the overheat detection pulse, reducing the delay in switching the ignition signal and increasing the output of the precharge pulse and multiple discharge pulse. It can be carried out without waste.
  • the overheat detection pulse may be output at every predetermined cycle of the combustion cycle of the internal combustion engine. For example, if the temperature of the ignition coil 300 exceeds the threshold value B (second temperature) (high temperature range) and the main ignition signal is also cut, the precharge pulse, multiple discharge pulse, and main ignition signal control device 1 (not shown), and only an overheat detection pulse is output at regular intervals (intermittently). Thereby, it is possible to quickly detect that the temperature of the ignition coil 300 has decreased and the air-fuel mixture can be ignited again while reducing the calculation load on the control device 1 and the load on the ignition control section 83. Note that such output control of (intermittent) overheating detection pulses at regular intervals may also be performed asynchronously to the combustion cycle when the rotation of the internal combustion engine is stopped due to idle stop control, etc., which will be described later. It is possible.
  • B second temperature
  • main ignition signal control device 1 not shown
  • FIG. 18 is a flowchart illustrating an example of fuel injection amount switching processing.
  • the overall control unit 81 (see FIG. 3) of the control device 1 acquires the time that has passed from the start of the internal combustion engine to the present. Then, the overall control unit 81 determines whether the time elapsed from the start to the present time is within a predetermined value (S310).
  • the predetermined value corresponds to the period until the warm-up described above is completed.
  • step S310 when it is determined that the time that has passed from startup to the present is not within a predetermined value (NO in S310), the overall control unit 81 ends the fuel injection amount switching process (S320). .
  • step S310 when it is determined in step S310 that the time that has passed from the start to the present is within a predetermined value (YES in S310), the overall control unit 81 transmits the precharge signal and the multiple ignition signal.
  • the ignition signal SA including the following is output (S330).
  • the overall control unit 81 determines whether or not the multiple ignition signal portion of the ignition signal SA is different from the portion corresponding to the multiple ignition signal of the return signal obtained from the output monitor circuit 832. (S340). If it is determined in step S340 that the ignition signal SA and the return signal are different, the overall control section 81 determines that the filter section 370 has blocked the multiple ignition signal. As described above, when the filter section 370 blocks the multiple ignition signal, the coil temperature of the ignition coil 300 is at least equal to or higher than the threshold value A (first temperature).
  • step S340 when it is determined that the ignition signal SA and the return signal are different (YES in S340), the overall control unit 81 sets the fuel injection amount to the first fuel injection amount (S350).
  • the overall control unit 81 turns off the precharge signal and the multiple ignition signal, and turns on the overheat detection pulse (overheat detection signal) (step S360). That is, the overall control unit 81 stops outputting the precharge signal and the multiple ignition signal, and outputs the overheat detection signal.
  • the overall control unit 81 stops outputting the precharge signal and the multiple ignition signal it is possible to reduce the amount of heat generated by the ignition coil 300 and lower the coil temperature.
  • the overall control unit 81 determines whether the overheat detection signal portion of the ignition signal SA is different from the portion of the return signal that corresponds to the overheat detection signal (S370). In step S370, when it is determined that the ignition signal SA and the return signal are different, the overall control section 81 determines that the filter section 370 has cut off the overheat detection pulse. When the filter section 370 cuts off the overheat detection pulse, the coil temperature of the ignition coil 300 is still equal to or higher than the threshold value A (first temperature).
  • step S370 when it is determined that the ignition signal SA and the return signal are different (YES in S370), the overall control unit 81 repeats step S370. That is, the overall control unit 81 repeats step S370 until the coil temperature becomes less than the threshold value A (first temperature).
  • step S370 when it is determined in step S370 that the ignition signal SA and the return signal match (if NO in S370), the overall control unit 81 determines that the coil temperature is less than the threshold value A (first temperature). Then, the overall control unit 81 stops outputting the overheat detection pulse and outputs a precharge signal and a multiple ignition signal (S380).
  • step S380 After the processing in step S380, or when it is determined in step S340 that the ignition signal SA and the return signal match (if NO in S340), the overall control unit 81 sets the fuel injection amount to the second fuel injection amount ( S390). After the process in step S390, the overall control unit 81 moves the process to step S310.
  • FIG. 19 is a timing chart showing the relationship between the operating state of an engine (internal combustion engine) installed in a typical automobile and the multiple ignition permission period.
  • Some modern engine (internal combustion engine) controls are equipped with idle stop control.
  • idle stop control the engine also stops when the vehicle stops, so the number of engine starts increases.
  • the lower the temperature of the electrode immediately before multiple ignition is performed the larger the temperature difference between the electrodes when multiple ignition is performed and when multiple ignition is not performed. Therefore, the lower the temperature of the electrode immediately before performing multiple ignition, the more heat-retaining effect of the flame core can be expected when multiple ignition is performed. Therefore, it is desirable to perform multiple ignitions when the electrode is at a low temperature when starting or restarting the engine.
  • the temperatures of the ignition coil 300 and the electrodes 210, 220 are sufficiently low. Therefore, it is also possible to start multiple ignition before the engine starts rotating. In this case, since there is no air flow within the cylinder, a high temperature-raising effect can be expected due to multiple ignitions.
  • FIG. 20 is a correlation graph showing the relationship between equivalence ratio and minimum ignition energy.
  • the horizontal axis of the graph shown in FIG. 20 is the equivalence ratio of the air-fuel mixture.
  • Equivalence ratio indicates the mass ratio of air and fuel. When the equivalence ratio is large, the fuel becomes rich, and when the equivalence ratio is small, the fuel becomes lean. When the equivalence ratio is 1, it becomes the stoichiometric air-fuel ratio.
  • the vertical axis of the graph shown in FIG. 20 is the minimum ignition energy in the main ignition.
  • Minimum ignition energy is a typical indicator of ignition performance. A common unit of minimum ignition energy is the joule.
  • Minimum ignition energy is the minimum discharge energy required to combust a mixture. If the minimum ignition energy is large, the ignition performance will be low, and if the minimum ignition energy is small, the ignition performance will be high.
  • the main determining factors for ignition performance are the equivalence ratio of the air-fuel mixture and multiple ignitions.
  • the equivalence ratio deviates from the stoichiometric mixture ratio (air-fuel ratio)
  • the minimum ignition energy increases and the ignition performance decreases.
  • the vaporization of the fuel is delayed, so the equivalence ratio of the mixture becomes smaller than the stoichiometric mixture ratio. Therefore, in the case of a cold start, the temperature of the engine (internal combustion engine) and the environment decreases, and the minimum ignition energy increases.
  • the ignition performance improves because the electrode absorbs heat from the flame kernel. Therefore, as shown by the dotted line in FIG. 20, it is possible to combust the air-fuel mixture with smaller ignition energy than when multiple ignition is not performed. In other words, if the minimum ignition energy at engine startup can be satisfied even when multiple ignitions are not performed, the improvement in ignition performance due to multiple ignitions is converted into a reduction in the equivalence ratio of the air-fuel mixture. be able to. This makes it possible to satisfy the minimum ignition energy and at the same time reduce the fuel injection amount. As a result, it is possible to improve fuel efficiency and reduce hydrocarbons.
  • the control device 1 controls an internal combustion engine including an ignition device having a spark plug 200 and an ignition coil 300 that causes the spark plug 200 to generate discharge.
  • the control device 1 includes an overall control section 81 (control section) that outputs an output signal to the ignition device.
  • the output signal is a multiple ignition signal for preheating the ignition plug 200 and a frequency different from the multiple ignition signal, a main ignition signal for igniting the air-fuel mixture by discharge of the ignition plug 200, and a main ignition signal for igniting the ignition coil 300. and a precharge signal for precharging.
  • the temperature of the electrodes 210, 220 can be increased, and the minimum ignition energy can be reduced as much as possible to improve ignition performance.
  • the ignitability of the spark plug 200 during main ignition can be improved, and generation of hydrocarbons can be suppressed.
  • the overall control unit 81 (control unit) according to the present embodiment outputs a multiple ignition signal before outputting the main ignition signal, and outputs a precharge signal before outputting the multiple ignition signal.
  • the electrodes 210, 220 and the intake air around the electrodes 210, 220 can be efficiently warmed before the air-fuel mixture is ignited by the discharge of the spark plug 200.
  • the precharge signal according to this embodiment has a lower frequency than the multiple ignition signal. Thereby, the charging energy of the ignition coil 300 can be increased as much as possible.
  • the overall control unit 81 (control unit) according to the present embodiment outputs a precharge signal when the temperature of the ignition coil 300 is less than the threshold value A (predetermined temperature). Thereby, when the temperature of the ignition coil 300 is less than the threshold value A and the ignition coil 300 is not in an overheated state, the charging energy of the ignition coil 300 can be increased.
  • the overall control unit 81 (control unit) according to the present embodiment stops outputting the precharge signal, and starts when outputting the precharge signal. also increases the amount of fuel injection.
  • the temperature of the ignition coil 300 is equal to or higher than the threshold value A and the ignition coil 300 is in an overheated state, it is possible to suppress the temperature of the ignition coil 300 from increasing.
  • the fuel injection amount it is possible to prevent the dielectric breakdown voltage from increasing even if the temperature of the ignition coil 300 decreases. As a result, misfires can be suppressed and generation of hydrocarbons can be suppressed.
  • the overall control unit 81 (control unit) according to the present embodiment reduces the fuel injection amount when outputting the precharge signal than when not outputting the precharge signal. Thereby, generation of hydrocarbons can be suppressed.
  • the output signal includes an overheat detection signal for detecting the state of the ignition coil 300.
  • the ignition device includes a temperature detection unit 351 that detects the temperature of the ignition coil 300, and cuts off a multiple ignition signal and an overheat detection signal among the output signals when the temperature of the ignition coil 300 becomes equal to or higher than a threshold value A (first temperature). It has a filter section 370.
  • the control device 1 internal combustion engine control device
  • the overall control section 81 compares the overheat detection signal and the return signal to determine whether the overheat detection signal is blocked by the filter section.
  • the overall control unit 81 can accurately determine whether the temperature of the ignition coil 300 is equal to or higher than the threshold value A (first temperature). As a result, precharging and multiple ignitions can be performed to the maximum extent while avoiding heat damage to the ignition coil 300.
  • the overall control unit 81 (control unit) according to this embodiment outputs an overheat detection signal at a timing after outputting the main ignition signal. This allows the ignition signal to be switched within the cycle. Further, the latest status of the temperature of the ignition coil 300 is reflected in the return signal of the overheat detection pulse, so that the delay in switching the ignition signal can be shortened.
  • the overall control unit 81 (control unit) according to the present embodiment outputs an overheat detection signal for each predetermined cycle among the combustion cycles of the internal combustion engine.
  • the overheat detection pulse can be output intermittently.
  • the overall control unit 81 (control unit) according to the present embodiment outputs a precharge signal when determining that the temperature of the ignition coil 300 is less than the threshold value A (first temperature).
  • the threshold value A first temperature
  • the charging energy of the ignition coil 300 is increased to start discharging between the electrodes 210 and 220, and the discharge causes the electrode to The temperature of 210 and 220 can be increased.
  • the overall control unit 81 controls at least one of a precharge signal and a multiple ignition signal. Stop outputting. Thereby, when the temperature of the ignition coil 300 is equal to or higher than the threshold value A and the ignition coil 300 is in an overheated state, it is possible to suppress the temperature of the ignition coil 300 from increasing.
  • the overall control unit 81 (control unit) according to the present embodiment outputs an overheat detection signal before outputting the main ignition signal when performing idle stop control (the internal combustion engine is restarted within a predetermined period). do. Then, when it is determined that the temperature of the ignition coil 300 is less than the threshold value A (first temperature), a precharge signal and a multiple ignition signal are output. Thereby, when the internal combustion engine is restarted and the ignition coil 300 is not in an overheated state, the charging energy of the ignition coil 300 can be increased as much as possible. Furthermore, the temperature of the electrodes 210 and 220 of the spark plug 200 can be increased without increasing the ignition energy due to multiple ignitions. As a result, the ignitability of the spark plug 200 can be improved, and generation of hydrocarbons can be suppressed.
  • the overall control unit 81 (control unit) determines that the temperature of the ignition coil 300 is equal to or higher than the threshold value A (first temperature)
  • the overall control unit 81 stops outputting the precharge signal, and outputs the precharge signal.
  • Increase the fuel injection amount compared to when outputting.
  • the temperature of the ignition coil 300 is equal to or higher than the threshold value A and the ignition coil 300 is in an overheated state
  • by increasing the fuel injection amount it is possible to prevent the dielectric breakdown voltage from increasing even if the temperature of the ignition coil 300 decreases. As a result, misfires can be suppressed and generation of hydrocarbons can be suppressed.
  • the overheat detection signal according to this embodiment is a single pulse signal. This can reduce wasteful charging and wasteful signal output operations. Further, it is possible to prevent the overheat detection signal from affecting the temperature rise of the ignition coil 300. Note that the overheat detection signal according to the present invention is not limited to a single pulse, but can be set to a number of pulses within a range that does not affect the temperature rise of the ignition coil.
  • the overheating detection signal has a frequency at which the output monitor circuit 832 (return detection function) can detect the return signal and the filter section 370 can cut it off. Thereby, by detecting that the overheat detection signal is not blocked by the filter section 370, it is possible to detect that the coil temperature is less than the threshold value A (first temperature). Further, even if the overheat detection signal is input to the igniter 340, it is possible to prevent sparks from flying to the electrodes 210, 220. As a result, the overheat detection signal can be prevented from affecting the temperature rise of the ignition coil 300.
  • the internal combustion engine control method is a method for controlling an internal combustion engine including an ignition device having a spark plug 200 and an ignition coil 300 that causes the spark plug 200 to generate discharge.
  • the overall control unit 81 (control unit) generates a multiple ignition signal for preheating the ignition plug 200 and a multiple ignition signal that have different frequencies, and generates a mixture by discharging the ignition plug 200.
  • a main ignition signal for igniting the ignition coil 300 and a precharge signal for precharging the ignition coil 300 are output to the ignition device.
  • the charging energy of the ignition coil 300 can be increased as much as possible.
  • the temperature of the electrodes 210 and 220 of the spark plug 200 can be increased without increasing the ignition energy due to multiple ignitions. As a result, the ignitability of the spark plug 200 can be improved, and generation of hydrocarbons can be suppressed.
  • Flow rate sensor 115... Intake Air temperature sensor, 120... Ring gear, 121... Crank angle sensor, 122... Water temperature sensor, 123... Crankshaft, 125... Accelerator pedal, 126... Accelerator position sensor, 130... Fuel tank, 131... Fuel pump, 132... Pressure regulator, 133... Fuel pipe, 134... Fuel injection device, 140... Cylinder pressure sensor, 150... Cylinder, 151... Intake valve, 152... Exhaust valve, 160... Exhaust manifold, 161... Three-way catalyst, 162... Upstream air-fuel ratio sensor, 163... Downstream air-fuel ratio sensor, 170... Piston, 200... Spark plug, 210... Center electrode, 220... Outer electrode, 230... Insulator, 300...
  • Ignition coil 310... Primary coil, 320... Secondary coil , 330... DC power supply, 340... Igniter, 350, 360... Temperature switch section, 351... Temperature detection section, 370... Filter section 500, 501... Electric circuit, 831... Energization control circuit, 832... Output monitor circuit

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  • Chemical & Material Sciences (AREA)
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Abstract

L'objectif de la présente invention est de supprimer la génération d'hydrocarbures à partir d'un moteur à combustion interne. Ce dispositif de commande de moteur à combustion interne commande un moteur à combustion interne comprenant un dispositif d'allumage ayant une bougie d'allumage et une bobine d'allumage qui amène la bougie d'allumage à générer une décharge. Le dispositif de commande de moteur à combustion interne comprend une unité de commande qui délivre un signal de sortie au dispositif d'allumage. Le signal de sortie comprend un signal d'allumage multiple pour préchauffer la bougie d'allumage, un signal d'allumage principal pour allumer un mélange air-carburant au moyen de la décharge de la bougie d'allumage, le signal d'allumage principal ayant une fréquence différente de celle du signal d'allumage multiple et un signal de précharge pour précharger la bobine d'allumage.
PCT/JP2022/020789 2022-05-19 2022-05-19 Dispositif de commande de moteur à combustion interne et procédé de commande de moteur à combustion interne WO2023223488A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61202682U (fr) * 1985-06-07 1986-12-19
JPH0326872A (ja) * 1989-06-26 1991-02-05 Hanshin Electric Co Ltd 容量放電式点火装置
JP2017072045A (ja) * 2015-10-06 2017-04-13 株式会社日本自動車部品総合研究所 点火装置
WO2019087748A1 (fr) * 2017-10-31 2019-05-09 日立オートモティブシステムズ株式会社 Dispositif d'allumage pour moteurs à combustion interne et dispositif de commande pour véhicules
WO2020085042A1 (fr) * 2018-10-24 2020-04-30 日立オートモティブシステムズ株式会社 Dispositif de commande pour moteur à combustion interne
US20210348588A1 (en) * 2019-12-06 2021-11-11 Weichai Torch Technology Co., Ltd. Spark plug heat up method via transient control of the spark discharge current

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61202682U (fr) * 1985-06-07 1986-12-19
JPH0326872A (ja) * 1989-06-26 1991-02-05 Hanshin Electric Co Ltd 容量放電式点火装置
JP2017072045A (ja) * 2015-10-06 2017-04-13 株式会社日本自動車部品総合研究所 点火装置
WO2019087748A1 (fr) * 2017-10-31 2019-05-09 日立オートモティブシステムズ株式会社 Dispositif d'allumage pour moteurs à combustion interne et dispositif de commande pour véhicules
WO2020085042A1 (fr) * 2018-10-24 2020-04-30 日立オートモティブシステムズ株式会社 Dispositif de commande pour moteur à combustion interne
US20210348588A1 (en) * 2019-12-06 2021-11-11 Weichai Torch Technology Co., Ltd. Spark plug heat up method via transient control of the spark discharge current

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