CN115735059A - Electronic control device - Google Patents

Abstract

An electronic control device controls supply of electric energy from an ignition coil to an ignition plug that discharges electric energy into a cylinder of an internal combustion engine by controlling energization of the ignition coil, the ignition coil including a main primary coil and a sub primary coil that are arranged on a primary side, respectively, and a secondary coil that is arranged on a secondary side, the electronic control device controlling energization of the ignition coil such that energization of the sub primary coil is started when a predetermined overlap energization start time has elapsed after the start of discharge of the main primary coil, and energization of the sub primary coil is ended when a predetermined overlap energization period corresponding to a rotation speed of the internal combustion engine has elapsed after the start of energization of the sub primary coil.

Description

Electronic control device

Technical Field

The present invention relates to an electronic control device.

Background

In recent years, in order to improve fuel efficiency of a vehicle, a control device of an internal combustion engine has been developed, which introduces a technique of operating the internal combustion engine by burning an air-fuel mixture thinner than a stoichiometric air-fuel ratio, a technique of taking in a part of an exhaust gas after combustion and re-introducing the exhaust gas, and the like.

In such a control device for an internal combustion engine, the amount of fuel and air in the combustion chamber may deviate from the theoretical values, and ignition failure of the fuel by the spark plug may easily occur. Therefore, there are methods of: by increasing the gas flow rate in the combustion chamber, the flow rate between the electrodes of the spark plug is increased to form a long discharge path, thereby extending the contact length between the discharge path and the gas to suppress misfire. However, if the flow velocity between the electrodes of the spark plug is high, the frequency of occurrence of blow-off of the discharge path and the consequent re-discharge is high, and it is difficult to form a long discharge path.

In order to form a long discharge path, it is necessary to continuously supply a current with a sufficient amount of current after the discharge path is formed, and thus it is necessary to maintain the discharge path as long as possible. However, generally, the internal energy of the ignition coil continuously decreases with time from the start of discharge, and thus the current required to maintain the discharge path is gradually not supplied. As a result, the gas cannot maintain the discharge path during combustion, and a problem arises in that re-discharge is required.

Patent document 1 discloses a control device for an internal combustion engine, which uses an ignition coil having a main primary coil and a sub-primary coil, generates a discharge spark in a spark plug by the main primary coil, compares a primary voltage with a threshold value, and superimposes a current by the sub-primary coil while the primary voltage exceeds the threshold value.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2019/198119

Disclosure of Invention

Technical problem to be solved by the invention

In the technique disclosed in patent document 1, since the energization time of the superimposed current varies depending on the magnitude of the primary voltage, the amount of heat generated by the ignition coil varies in each cycle of the internal combustion engine. In order to cope with such a cyclic variation in the amount of heat generation, it is necessary to set a cooling capacity including an excessive margin for the ignition coil, which causes a problem of an increase in the volume of the ignition coil and an increase in cost.

The present invention has been made in view of the above problems, and an object of the present invention is to control an increase in volume and cost of an ignition coil, and to achieve both improvement in fuel efficiency of an internal combustion engine and suppression of ignition failure of fuel.

Technical scheme for solving technical problems

An electronic control device according to a first aspect of the present invention controls supply of electric energy from an ignition coil to a spark plug that discharges electric energy into a cylinder of an internal combustion engine by controlling energization of the ignition coil, the ignition coil including a main primary coil and a sub primary coil that are arranged on a primary side, respectively, and a secondary coil that is arranged on a secondary side, the electronic control device controlling energization of the ignition coil such that energization of the sub primary coil is started when a predetermined overlap energization start time has elapsed after discharge of the main primary coil is started, and energization of the sub primary coil is ended when a predetermined overlap energization period corresponding to a rotation speed of the internal combustion engine has elapsed after energization of the sub primary coil is started.

An electronic control device according to a second aspect of the present invention controls supply of electric energy from an ignition coil to a spark plug that discharges electric energy into a cylinder of an internal combustion engine by controlling energization of the ignition coil, the ignition coil including a main primary coil and a sub primary coil that are arranged on a primary side, respectively, and a secondary coil that is arranged on a secondary side, the electronic control device controlling energization of the ignition coil such that energization of the sub primary coil is started when a predetermined overlap energization start time has elapsed after discharge of the main primary coil is started, and energization of the sub primary coil is ended when a predetermined overlap energization period has elapsed after energization of the sub primary coil is started, and the overlap energization start time is increased as the discharge start timing of the main primary coil becomes earlier according to an operating state of the internal combustion engine.

Effects of the invention

According to the present invention, it is possible to achieve both fuel efficiency improvement of an internal combustion engine and suppression of ignition failure of fuel while suppressing increase in volume and cost of an ignition coil.

Drawings

Fig. 1 is a diagram illustrating a configuration of a main part of an internal combustion engine and an internal combustion engine control device according to an embodiment.

Fig. 2 is a partially enlarged view illustrating the spark plug.

Fig. 3 is a functional block diagram illustrating a functional configuration of the control device according to the embodiment.

Fig. 4 is a diagram illustrating a relationship between an operation state of the internal combustion engine and a flow rate of gas around the spark plug.

Fig. 5 is a graph illustrating a relationship between a discharge path and a flow rate of the spark plug between the electrodes.

Fig. 6 is a diagram illustrating a circuit including a conventional ignition coil.

Fig. 7 is a diagram showing an example of a timing chart for explaining a relationship between a control signal input to an ignition coil and an output in a conventional discharge control.

Fig. 8 is a diagram illustrating a circuit including the ignition coil according to embodiment 1.

Fig. 9 is a diagram showing an example of a scatter chart in which measurement results of the re-discharge voltage and the re-discharge time are recorded.

Fig. 10 is a diagram showing an example of a histogram in which measurement results of the re-discharge time are recorded.

Fig. 11 is a diagram showing an example of a timing chart for explaining a relationship between a control signal input to an ignition coil and an output in the discharge control according to embodiment 1.

Fig. 12 is a diagram illustrating the effect of the present invention.

Fig. 13 is an example of a flowchart for explaining the method of setting the superimposed energization start time according to embodiment 1.

Fig. 14 is an example of a flowchart for explaining a method of controlling the sub-primary coil according to embodiment 1.

Fig. 15 is a diagram illustrating a circuit including the ignition coil according to embodiment 2.

Fig. 16 is an example of a flowchart for explaining a method of setting the superimposed energization start time and the superimposed energization voltage range according to embodiment 2.

Fig. 17 is an example of a flowchart for explaining a method of controlling the sub-primary coil according to embodiment 2.

Fig. 18 is a diagram illustrating a circuit including the ignition coil according to embodiment 3.

Fig. 19 is an example of map information showing a relationship between the engine speed and the on period of the ignition signal SA.

Fig. 20 is an example of a graph showing a relationship between the on period of the ignition signal SA and the on period of the ignition signal SB.

Fig. 21 is an example of a flowchart for explaining a method of controlling the sub-primary coil according to embodiment 3.

Fig. 22 is a diagram showing an example of a timing chart for explaining a relationship between a control signal input to an ignition coil and an output in the discharge control according to embodiment 4.

Fig. 23 is an example of a graph showing the relationship between the gas flow rate between the electrodes and the corrected added value of the rise time of the ignition signal SB.

Fig. 24 is an example of a flowchart for explaining a method of controlling the sub-primary coil according to embodiment 4.

Detailed Description

Next, a control device for an internal combustion engine according to an embodiment of the present invention will be described.

Next, a control device 1 as one mode of an electronic control device according to an embodiment of the present invention will be described. In this embodiment, a case will be exemplified in which the control device 1 controls the discharge (ignition) of the ignition plug 200 provided in each cylinder 150 of the four-cylinder internal combustion engine 100.

In the present embodiment, a combination of a part or all of the structure of the internal combustion engine 100 and a part or all of the structure of the control device 1 is hereinafter referred to as a control device 1 of the internal combustion engine 100.

[ internal Combustion Engine ]

Fig. 1 is a diagram illustrating the configurations of main portions of an internal combustion engine 100 and an ignition device for an internal combustion engine.

Fig. 2 is a partially enlarged view illustrating the electrodes 210, 220 of the spark plug 200.

In the internal combustion engine 100, air taken in from the outside flows through the air cleaner 110, the intake pipe 111, and the intake manifold 112, and flows into each cylinder 150 when the intake valve 151 is opened. The amount of air flowing into each cylinder 150 is adjusted by the throttle valve 113, and the amount of air adjusted by the throttle valve 113 is measured by the flow sensor 114.

The throttle valve 113 is provided with a throttle opening sensor 113a that detects the opening of the throttle valve. Information on the opening degree of the throttle valve 113 detected by the throttle opening sensor 113a is output to a Control Unit (ECU) 1.

Although an electric throttle valve driven by an electric motor is used as the throttle valve 113, other methods may be used as long as the air flow rate can be appropriately adjusted.

The temperature of the gas flowing into each cylinder 150 is detected by the intake air temperature sensor 115.

The crank angle sensor 121 is provided radially outside the ring gear 120 mounted to the crank shaft 123. The crank angle sensor 121 detects the rotation angle of the crank shaft 123. In the present embodiment, crank angle sensor 121 detects the rotation angle of crankshaft 123 every 10 ° and every combustion cycle, for example.

The water temperature sensor 122 is provided on a water jacket (not shown) of the cylinder head. The temperature of the cooling water of the internal combustion engine 100 is detected by the water temperature sensor 122.

The vehicle is provided with an Accelerator Position Sensor (APS) 126 that detects the displacement amount (depression amount) of an Accelerator pedal 125. The driver's requested torque is detected by the accelerator position sensor 126. The driver's requested torque detected by this accelerator position sensor 126 is output to the control device 1 described later. The control device 1 controls the throttle valve 113 based on the requested torque.

The fuel stored in the fuel tank 130 is sucked and pressurized by the fuel pump 131, and then flows through the fuel pipe 133 provided with the pressure regulator 132 to be guided to the fuel injection valve (injector) 134. The fuel output from the fuel pump 131 is adjusted to a predetermined pressure by a pressure regulator 132, and is injected from a fuel injection valve (injector) 134 into each cylinder 150. As a result of the pressure regulation by the pressure regulator 132, the excess fuel is returned to the fuel tank 130 via a return pipe (not shown).

A Cylinder head (not shown) of the internal combustion engine 100 is provided with a Combustion Pressure Sensor (CPS) 140. The combustion pressure sensor 140 is provided in each cylinder 150, and detects the pressure (combustion pressure) in the cylinder 150.

The combustion pressure sensor 140 uses a piezoelectric or gauge type pressure sensor, and is capable of detecting the combustion pressure (in-cylinder pressure) in the cylinder 150 in a wide temperature region.

Each cylinder 150 is provided with an exhaust valve 152 and an exhaust manifold 160 for discharging combusted gas (exhaust gas) to the outside of the cylinder 150. A three-way catalyst 161 is provided on the exhaust side of the exhaust manifold 160. When the exhaust valve 152 is opened, exhaust gas is expelled from the cylinder 150 to an exhaust manifold 160. The exhaust gas is purified by a three-way catalyst 161 through an exhaust manifold 160 and then discharged to the atmosphere.

The upstream air-fuel ratio sensor 162 is provided upstream of the three-way catalyst 161. The upstream air-fuel ratio sensor 162 continuously detects the air-fuel ratio of the exhaust gas discharged from each cylinder 150.

Further, 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 of the switch in the vicinity of the stoichiometric air-fuel ratio. In the present embodiment, the downstream air-fuel ratio sensor 163 is, for example, an O2 sensor.

Further, the ignition plugs 200 are provided at the upper portions of the respective cylinders 150. By the discharge (ignition) of the ignition plug 200, the spark ignites the mixture of air and fuel in the cylinder 150, and the piston 170 is pressed by the explosion in the cylinder 150. The piston 170 is pressed, and the crankshaft 123 rotates.

An ignition coil 300 for generating electric power (voltage) supplied to the spark plug 200 is connected to the spark plug 200. According to the voltage generated in the ignition coil 300, an electric discharge is generated between the center electrode 210 and the outer electrode 220 of the spark plug 200 (see fig. 2).

As shown in fig. 2, in the spark plug 200, the center electrode 210 is supported in an insulated state by an insulator 230. A predetermined voltage (for example, 20,000V to 40,000V in the present embodiment) is applied to the center electrode 210.

The outer electrode 220 is grounded. When a predetermined voltage is applied to the center electrode 210, a discharge (ignition) is generated between the center electrode 210 and the outer electrode 220.

In the spark plug 200, the voltage at which the discharge (ignition) occurs due to the dielectric breakdown of the gas component varies depending on the state of the gas (gas) present between the center electrode 210 and the outer electrode 220 and the cylinder internal pressure. The voltage at which this discharge occurs is referred to as the dielectric breakdown voltage.

The discharge control (ignition control) of the ignition plug 200 is performed by an ignition control section 83 of the control device 1 described later.

Returning to fig. 1, output signals from various sensors such as the throttle opening sensor 113a, the flow sensor 114, the crank angle sensor 121, the accelerator position sensor 126, the water temperature sensor 122, and the combustion pressure sensor 140 are output to the control device 1. The control device 1 detects the operating state of the internal combustion engine 100 based on output signals from these various sensors, and controls the amount of air output into the cylinder 150, the fuel injection amount, the ignition timing of the ignition plug 200, and the like.

[ hardware configuration of control device ]

Next, the overall structure of the hardware of the control device 1 will be described.

As shown in fig. 1, the control device 1 includes an Analog Input Unit 10, a Digital Input Unit 20, an a/D (Analog/Digital: analog/Digital) conversion Unit 30, a RAM (Random Access Memory) 40, an MPU (Micro-Processing Unit) 50, a ROM (Read Only Memory) 60, an I/O (Input/Output: input/Output) port 70, and an Output circuit 80.

Analog output signals from various sensors such as the throttle opening sensor 113a, the flow rate sensor 114, the accelerator position sensor 126, the upstream air-fuel ratio sensor 162, the downstream air-fuel ratio sensor 163, the combustion pressure sensor 140, and the water temperature sensor 122 are input to the analog input unit 10.

The a/D conversion section 30 is connected to the analog input section 10. Analog output signals from various sensors input to the analog input unit 10 are subjected to signal processing such as noise removal, converted into digital signals by the a/D conversion unit 30, and stored in the RAM 40.

The digital output signal from the crank angle sensor 121 is input to the digital input section 20.

The I/O port 70 is connected to the digital input section 20, and a digital output signal input to the digital input section 20 is stored in the RAM40 via the I/O port 70.

The respective output signals stored in the RAM40 are subjected to arithmetic processing by the MPU 50.

The MPU50 executes a control program (not shown) stored in the ROM60, thereby performing arithmetic processing on the output signals stored in the RAM40 according to the control program. The MPU50 calculates control values that define the operation amounts of the respective actuators (e.g., the throttle valve 113, the pressure regulator 132, the ignition plug 200, etc.) that drive the internal combustion engine 100, based on the control programs, and temporarily stores the control values in the RAM 40.

A control value that defines the operation amount of the actuator stored in the RAM40 is output to the output circuit 80 via the I/O port 70.

The output circuit 80 is provided with a function of an ignition control portion 83 (see fig. 3) that controls the voltage applied to the ignition plug 200, and the like.

[ function blocks of control device ]

Next, a functional structure of the control device 1 according to the embodiment of the present invention will be explained.

Fig. 3 is a functional block diagram illustrating a functional configuration of the control device 1 according to the embodiment of the present invention. The functions of the control apparatus 1 are realized by the output circuit 80 by the MPU50 executing a control program stored in the ROM60, for example.

As shown in fig. 3, the output circuit 80 of the control device 1 according to embodiment 1 includes an overall control unit 81, a fuel injection control unit 82, and an ignition control unit 83.

The overall control portion 81 is connected to the accelerator position sensor 126 and the combustion pressure sensor 140 (CPS), and receives the requested torque (acceleration signal S1) from the accelerator position sensor 126 and the output signal S2 from the combustion pressure sensor 140.

The overall control unit 81 performs overall control of the fuel injection control unit 82 and the ignition control unit 83 based on the requested torque (acceleration signal S1) from the accelerator position sensor 126 and the output signal S2 from the combustion pressure sensor 140.

The fuel injection control portion 82 is connected to a cylinder determination portion 84 for determining each cylinder 150 of the internal combustion engine 100, an angle information generation portion 85 for measuring the crank angle of the crankshaft 123, and a rotation speed information generation portion 86 for measuring the engine rotation speed, and receives cylinder determination information S3 from the cylinder determination portion 84, crank angle information S4 from the angle information generation portion 85, and engine rotation speed information S5 from the rotation speed information generation portion 86.

Further, the fuel injection control portion 82 is connected to an intake air amount measuring portion 87 for measuring the intake air amount of air taken into the cylinder 150, a load information generating portion 88 for measuring the engine load, a water temperature measuring portion 89 for measuring the temperature of the engine cooling water, and receives intake air amount information S6 from the intake air amount measuring portion 87, engine load information S7 from the load information generating portion 88, and cooling water temperature information S8 from the water temperature measuring portion 89.

The fuel injection control portion 82 calculates the injection amount and the injection time of the fuel injected from the fuel injection valve 134 based on the received various information (fuel injection valve control information S9), and controls the fuel injection valve 134 based on the calculated injection amount and the calculated injection time of the fuel.

The ignition control unit 83 is connected to the cylinder determination unit 84, the angle information generation unit 85, the rotation speed information generation unit 86, the load information generation unit 88, and the water temperature measurement unit 89, in addition to the overall control unit 81, and receives various information therefrom.

The ignition control unit 83 calculates the amount of current (conduction angle) to be conducted to the primary coil (not shown) of the ignition coil 300, the conduction start time, and the time (ignition time) at which the current to be conducted to the primary coil is cut off, based on the received various information.

Ignition control unit 83 outputs ignition signal SA to the primary side coil of ignition coil 300 based on the calculated energization angle, energization start timing, and ignition timing, and performs discharge control (ignition control) by ignition plug 200.

The function of ignition control unit 83 for performing ignition control of spark plug 200 using ignition signal SA corresponds to at least the internal combustion engine control device of the present invention.

Fig. 4 is a diagram illustrating a relationship between an operation state of the internal combustion engine 100 and a gas flow rate around the spark plug 200. As shown in fig. 4, generally, the higher the engine speed and load, the higher the gas flow rate in the cylinder 150, and the higher the gas flow rate around the ignition plug 200. Therefore, the gas flows at a high speed between the center electrode 210 and the outer electrode 220 of the spark plug 200. In the internal combustion engine 100 that performs Exhaust Gas Recirculation (EGR), the EGR rate is set according to the relationship between the engine speed and the load, as shown in fig. 4, for example. Further, the higher the EGR rate is set, the larger the high EGR range is, the more fuel efficiency and exhaust gas can be reduced, but the more likely the ignition failure occurs in the spark plug 200.

Fig. 5 is a diagram illustrating a relationship between a discharge path of the spark plug 200 between the electrodes and a flow rate. When a high voltage is generated in the secondary side coil of the ignition coil 300 and insulation breakdown is generated between the center electrode 210 and the outer side electrode 220 of the spark plug 200, a discharge path is formed between the electrodes of the spark plug 200 until a current flowing between these electrodes becomes a constant value or less. When the combustible gas comes into contact with the discharge path, a flame kernel grows until combustion. Since the discharge path moves under the influence of the gas flow between the electrodes, the longer the gas flow rate, the longer the discharge path is formed in a short time, and the lower the gas flow rate, the shorter the discharge path. Fig. 5 (a) shows an example of the discharge path 211 when the gas flow rate is high, and fig. 5 (b) shows an example of the discharge path 212 when the gas flow rate is low.

In the case where the internal combustion engine 100 is operated at a high EGR rate, even if the combustible gas comes into contact with the discharge path, the probability of flame kernel growth decreases, and therefore, it is necessary to increase the chance of the combustible gas coming into contact with the discharge path. As described above, since the discharge path is generated by breaking down the insulation of the gas, if the current required to maintain the discharge path is constant, it is necessary to output power corresponding to the length of the discharge path. Therefore, it is preferable that, in the case where the gas flow rate is high, the energization control of the ignition coil 300 is performed so that a large electric power is output from the ignition coil 300 to the ignition plug 200 in a short time, thereby forming a longer discharge path 211 as shown in fig. 5 (a), so that a chance of contact with a larger space of gas is obtained. On the other hand, when the gas flow rate is low, it is preferable to maintain the formation of the short discharge path 212 as shown in fig. 5 (b) by performing energization control of the ignition coil 300 so that a small electric power is continuously output from the ignition coil 300 to the ignition plug 200 for a long time, thereby obtaining a chance of contact with the gas passing through the vicinity of the electrode of the ignition plug 200 for a longer time.

[ conventional ignition coil Circuit ]

Next, prior to the description of the embodiments of the present invention, a conventional ignition coil will be described.

Fig. 6 is a diagram illustrating a circuit 400C including a conventional ignition coil 300C as a comparative example of the present invention. In the circuit 400C, the ignition coil 300C 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 side coil 310 is connected to a direct current power supply 330. Accordingly, a prescribed voltage (e.g., 12V) is applied to the primary side coil 310.

The other end of the primary side coil 310 is connected to an igniter 340 and is grounded via the igniter 340. In the igniter 340, a Transistor, a Field Effect Transistor (FET), or the like is used.

The base (B) terminal of the igniter 340 is connected to the ignition control section 83. The ignition signal SA output from the ignition control unit 83 is input to the base (B) terminal of the igniter 340. When the ignition signal SA is input to the base (B) terminal of the igniter 340, an energized state is established between the collector (C) terminal and the emitter (E) terminal of the igniter 340, and a current flows between the collector (C) terminal and the emitter (E) terminal. Therefore, the ignition signal SA is output from the ignition control unit 83 to the primary coil 310 of the ignition coil 300 via the igniter 340, and the current flows through the primary coil 310 to store the electric power (electric energy).

When the output of the ignition signal SA from the ignition control unit 83 is stopped and the current flowing through the primary coil 310 is cut off, a high voltage corresponding to the coil turn ratio with respect to the primary coil 310 is generated in the secondary coil 320.

The high voltage generated in the secondary side coil 320 by the ignition signal SA is applied to the spark plug 200 (center electrode 210), thereby generating a potential difference between the center electrode 210 and the outer electrode 220 of the spark plug 200. When the potential difference generated between the center electrode 210 and the outer electrode 220 is equal to or greater than the dielectric breakdown voltage Vm of the gas (the air-fuel mixture in the cylinder 150), the gas component is subjected to dielectric breakdown, and an electric discharge is generated between the center electrode 210 and the outer electrode 220, thereby igniting (igniting) the fuel (the air-fuel mixture).

In the comparative example, the ignition control unit 83 controls the energization of the ignition coil 300A using the ignition signal SA by the operation of the circuit 400C as described above. Therefore, ignition control for controlling the spark plug 200 is implemented.

[ discharge control of conventional ignition coil ]

Next, a description will be given of a conventional discharge control of an ignition coil, and fig. 7 is a diagram showing an example of a timing chart illustrating a relationship between a control signal input to the ignition coil and an output in the conventional discharge control. Fig. 7 is a timing chart showing an example of discharging the ignition plug 200 when the gas is at a high flow rate using the conventional ignition coil 300C. Fig. 7 shows a relationship among the ignition signal SA output from the ignition control section 83, the primary current I1 flowing through the primary side coil 310 in accordance with the ignition signal SA, the electric energy E accumulated in the ignition coil 300C, the secondary current I2 flowing through the secondary side coil 320, and the secondary voltage V2 generated in the secondary side coil 320. As shown in fig. 6, the measurement points of the secondary current I2 and the secondary voltage V2 are provided between the ignition plug 200 and the ignition coil 300C. The measurement point of the primary current I1 is provided between the dc power supply 330 and the ignition coil 300C.

When the ignition signal SA becomes HIGH, the igniter 340 energizes the primary coil 310, and the primary current I1 rises. During energization of the primary side coil 310, the electric energy E in the ignition coil 300C rises together with time.

Thereafter, when the ignition signal SA becomes LOW, the igniter 340 cuts off the energization of the primary side coil 310. Accordingly, an electromotive force is generated to the secondary side coil 320, and the supply of the electric power E from the ignition coil 300C to the ignition plug 200 is started. When the insulation between the electrodes of the spark plug 200 is broken down, the discharge of the spark plug 200 is started. The discharge of the spark plug 200 accompanied by such insulation breakdown is referred to as capacitive discharge. After the start of the discharge of the spark plug 200, the electric energy E in the ignition coil 300C decreases together with time, maintaining the discharge of the spark plug 200. The discharge of the spark plug 200 that does not accompany such insulation breakdown is referred to as induction discharge.

The secondary current I2 rises greatly when the capacitor is discharged. The secondary current I2 caused by the discharge of the capacitor ends in a short time. When the discharge of the spark plug 200 is started and a discharge path is formed between the electrodes, the secondary current I2 sharply decreases, and decreases together with time at the time of the subsequent induction discharge. Since the discharge path is elongated with the flow of the gas, the secondary voltage V2 rises with the passage of time. At this time, the magnitude of the secondary current I2 required to maintain the discharge path varies according to the flow rate of the gas existing between the electrodes of the spark plug 200.

When the secondary current I2 is between the minimum value required to maintain the discharge path and the maximum value that cannot discharge, the spark plug 200 repeatedly blows out the discharge path and discharges again. The range of the secondary current I2 in which the discharge path is repeatedly blown out and discharged again is hereinafter referred to as an "intermittent operation region". That is, when the secondary current I2 enters the intermittent operation region, the discharge path cannot be maintained, the discharge path is blown out by the airflow, and the discharge of the ignition plug 200 is interrupted. At this time, even if the discharge path is lost, the electric energy E in the ignition coil 300C remains, and therefore, re-discharge (restrike: re-ignition) accompanied by the capacitor discharge is generated in the ignition plug 200. In the example of fig. 7, the number of times of the first discharge and the second discharge is 1 and 3, respectively, and the number of times of the capacitor discharge is 4.

When the electric energy E in the ignition coil 300C decreases, the secondary current I2 also decreases. When the secondary current I2 becomes equal to or less than the maximum value at which discharge cannot be performed, discharge of the spark plug 200 is stopped.

In the present invention, the ignition coil 300 having two primary side coils is used instead of the ignition coil 300C described in fig. 6, and the ignition plug 200 discharge in which the number of times of capacitor discharge is suppressed is realized by performing discharge control on the ignition coil 300.

Embodiment 1: circuit of ignition coil

Next, a circuit 400 including the ignition coil 300 according to embodiment 1 of the present invention will be described.

Fig. 8 is a diagram illustrating a circuit 400 including the ignition coil 300 according to embodiment 1 of the present invention. In the circuit 400, the ignition coil 300 includes two types of primary coils 310 and 360 wound with a predetermined number of turns, and a secondary coil 320 wound with a larger number of turns than the primary coils 310 and 360. Here, when the spark plug 200 is ignited, first, the power from the primary side coil 310 is supplied to the secondary side coil 320, and the power from the primary side coil 360 is supplied to the secondary side coil 320 in an overlapping manner with the power. Therefore, the primary coil 310 is hereinafter referred to as a "main primary coil", and the primary coil 360 is hereinafter referred to as a "sub-primary coil". In addition, the current flowing through the main primary coil 310 is referred to as "main primary current", and the current flowing through the sub-primary coil 360 is referred to as "sub-primary current".

One end of the main primary coil 310 is connected to a dc power supply 330. Therefore, a prescribed voltage (e.g., 12V in the embodiment) is applied to the main primary coil 310.

The other end of the main primary coil 310 is connected to the igniter 340 and is grounded via the igniter 340. A Transistor, a Field Effect Transistor (FET), or the like is used for the igniter 340.

The base (B) terminal of the igniter 340 is connected to the ignition control section 83. The ignition signal SA output from the ignition control unit 83 is input to the base (B) terminal of the igniter 340. When the ignition signal SA is input to the base (B) terminal of the igniter 340, an energized state is established between the collector (C) terminal and the emitter (E) terminal of the igniter 340, and a current flows between the collector (C) terminal and the emitter (E) terminal. Therefore, the ignition signal SA is output from the ignition control unit 83 to the main primary coil 310 of the ignition coil 300 via the igniter 340, and the main primary coil 310 flows the main primary current and stores the electric power (electric energy).

When the output of the ignition signal SA from the ignition control section 83 is stopped and the main primary current flowing through the main primary coil 310 is cut off, a high voltage corresponding to the coil turns ratio for the main primary coil 310 is generated in the secondary side coil 320.

One end of the sub-primary coil 360 is common to the main primary coil 310 and connected to the dc power supply 330. Therefore, a predetermined voltage (for example, 12V in the embodiment) is applied to the secondary primary coil 360.

The other end of the secondary primary coil 360 is connected to the igniter 350 and is grounded via the igniter 350. A Transistor, a Field Effect Transistor (FET), or the like is used for the igniter 350.

The base (B) terminal of the igniter 350 is connected to a phase control section 380 provided in the ignition control section 83. The phase control section 380 outputs the ignition signal SB as a signal for controlling on/off of the igniter 350. The ignition signal SB output from the ignition control section 380 is input to the base (B) terminal of the igniter 350. When the ignition signal SB is input to the base (B) terminal of the igniter 350, an energization state corresponding to a voltage change of the ignition signal SB is established between the collector (C) terminal and the emitter (E) terminal of the igniter 350, and a current corresponding to the voltage change of the ignition signal SB flows between the collector (C) terminal and the emitter (E) terminal. Therefore, the ignition signal SB is output from the ignition control section 83 to the sub-primary coil 360 of the ignition coil 300 via the igniter 350, and the sub-primary coil 360 generates electric power (electric energy) by flowing a sub-primary current.

When the output of the ignition signal SB from the phase control section 380 changes and the sub-primary current flowing through the sub-primary coil 360 changes, a high voltage corresponding to the coil turn ratio for the sub-primary coil 360 is generated in the secondary side coil 320.

The high voltage generated in the secondary side coil 320 by the ignition signal SA and the high voltage generated in the secondary side coil 320 by the ignition signal SB are added and applied to the spark plug 200 (center electrode 210), thereby generating a potential difference between the center electrode 210 and the outer electrode 220 of the spark plug 200. When the potential difference generated between the center electrode 210 and the outer electrode 220 is equal to or greater than the dielectric breakdown voltage Vm of the gas (the air-fuel mixture in the cylinder 150), the gas component is subjected to dielectric breakdown, and electric discharge is generated between the center electrode 210 and the outer electrode 220 to ignite (ignite) the fuel (the air-fuel mixture).

The phase control section 380 performs output control of the ignition signal SB such that the ignition signal SB is raised at a time a at which a predetermined overlap energization start time elapses from the start of the fall time S of the ignition signal SA, and then the ignition signal SB is lowered at a time B at which a predetermined overlap energization period elapses. Thereby, the power from the sub-primary coil 360 is supplied to the spark plug 200 overlapping the power supplied from the main primary coil 310, and the discharge path formed between the center electrode 210 and the outer electrode 220 is maintained. In addition, a specific output control method of the ignition signal SB will be described later.

The ignition control unit 83 controls the energization of the ignition coil 300 using the ignition signals SA and SB by the operation of the circuit 400 described above. Therefore, ignition control for controlling the spark plug 200 is implemented.

Further, the phase control section 380 may not be provided inside the ignition control section 83. That is, the ignition control section 83 and the phase control section 380 may be configured separately. In either case, since the phase control unit 380 operates under the control of the ignition control unit 83, it can be said that the ignition control unit 83 controls the energization of the ignition coil 300.

Embodiment 1: discharge control of ignition coil

Next, the discharge control of the ignition coil according to embodiment 1 of the present invention will be described. In the present embodiment, the phase control unit 380 of the ignition control unit 83 determines the output time and output timing of the ignition signal SB based on a predetermined overlap energization start time and overlap energization period. The superimposed energization start time is a time from a falling timing S of the ignition signal SA to a rising timing a of the ignition signal SB, that is, a time from the start of discharge of the main primary coil 310 by the ignition signal SA to the start of energization of the sub-primary coil 360. On the other hand, the superimposed energization period is a time from the rise timing a to the fall timing B of the ignition signal SB, that is, a time from the start of energization of the sub-primary coil 360 to the end of energization. These times are set based on the result of measuring the occurrence state of the re-discharge when the ignition plug 200 is discharged in the cylinder 150 at the development stage of the ignition control section 83. An example of a specific method thereof is described below.

First, in the circuit 400 shown in fig. 8, a voltage sensor is provided between the ignition plug 200 and the ignition coil 300, and the secondary voltage V2 at the time of discharging the ignition plug 200 in the cylinder 150 is detected using the voltage sensor. In addition, instead of the circuit 400, a secondary voltage V2 at the time of discharging the ignition plug 200 in the cylinder 150 may be detected using the circuit 400C shown in fig. 6. Then, based on the obtained value of the secondary voltage V2, the secondary voltage V2 at a point in time immediately before the occurrence of the re-discharge of the spark plug 200 (hereinafter referred to as "re-discharge voltage") is measured, and based on the period of measuring the re-discharge voltage, the time from the start of the discharge of the spark plug 200 to the re-discharge (hereinafter referred to as "re-discharge time") is measured.

For example, in the waveform of the secondary voltage V2 shown in fig. 7, a maximum value of the secondary voltage V2 in the discharge period of the spark plug 200, that is, a value immediately before the secondary voltage V2 sharply decreases after the start of discharge is defined as V2max. By obtaining the value of V2max and the time (V2 max period) from the drop of the ignition signal SA to the detection of V2max from the detection result of the secondary voltage V2, the re-discharge voltage and the re-discharge time can be measured. In detecting V2max, the time derivative dV2/dt of the secondary voltage V2 may be obtained, and the value of the time derivative dV2/dt may be compared with a predetermined threshold value. In this way, the point at which the secondary voltage V2 drops sharply can be easily detected as V2max, and the re-discharge time can be measured.

The re-discharge voltage and the re-discharge time are measured a plurality of times based on the detection result of the secondary voltage V2, and the set values of the superimposed energization start time and the superimposed energization period are determined by statistically processing the measurement results. This method is explained below with reference to fig. 9 and 10.

Fig. 9 is a diagram showing an example of a scatter chart in which measurement results of the redischarge voltage and the redischarge time are recorded. In the scatter diagram, the abscissa indicates the period of V2max starting from the falling period S of the ignition signal SA, i.e., the re-discharge time, and the ordinate indicates the value of V2max, i.e., the re-discharge voltage.

During operation of the internal combustion engine 100, there is a deviation in the gas flow between the electrodes of the spark plug 200 in the cylinder 150, the temperature of the electrodes in each combustion cycle. Therefore, the values of the V2max and V2max periods vary rather than being constant in each combustion cycle as shown in fig. 9. However, when an attempt is made to supply an overlap current to the ignition plug 200 through the sub-primary coil 360 in the range of all the re-discharge times corresponding to the variation range of the Vmax period, the energization time of the sub-primary coil 360 is excessive. As a result, the power consumption and the heat generation amount of the ignition coil 300 are excessively large, and the cooling capacity of the ignition coil 300 must be larger than necessary to mount the ignition coil 300, which may increase the volume and the cost.

Therefore, in the present embodiment, in the distribution of the respective measurement results when the redischarging time is measured a plurality of times, the energization period allowable for the sub-primary coil 360 in terms of heat generation is set as the overlap energization period, and the overlap energization start time is set so that the number of times of occurrence of the redischarging of the spark plug 200 is maximized in the overlap energization period. Therefore, it is not necessary to increase the cooling capacity of the ignition coil 300, and the occurrence of the re-discharge in the ignition plug 200 is suppressed as much as possible, and both the suppression of the power consumption of the ignition coil 300 and the extension of the discharge path between the electrodes of the ignition plug 200 are compatible.

Specifically, for example, in the scatter diagram shown in fig. 9, line segments 91 and 92 corresponding to the rising timing a and the falling timing B of the ignition signal SB, respectively, are set, and the interval between the line segment 91 and the line segment 92 is fixed so as to match the energization period of the sub-primary coil 360 that is allowable in terms of heat generation, in accordance with the rotation speed of the internal combustion engine 100. In this state, the line segments 91 and 92 are moved laterally on the scatter diagram, and a position where the number of measurement points entering between the line segment 91 and the line segment 92 is the maximum is searched for. The overlap energization start time can be set based on the position of the line segment 91 thus searched. In addition, in the case where there is no problem in the heat generation of the ignition coil 300, the overlapping energization start timing may be set so that all the measurement points enter between the line segment 91 and the line segment 92.

In the scatter diagram shown in fig. 9, line segments 93 and 94 corresponding to the lower limit voltage C and the upper limit voltage D of the secondary voltage V2, respectively, may be set. For example, the positions of the line segments 93 and 94 are determined so as to satisfy predetermined conditions based on the intervals between the line segments 93 and 94, the number of measurement points between the line segments 93 and 94, and the like. At this time, all the measurement points may enter between the line segment 93 and the line segment 94. The lower limit voltage C and the upper limit voltage D of the secondary voltage V2 are set according to the positions of the line segments 93 and 94 thus set, and the ignition signal SB can be controlled using these. A control method of the ignition signal SB using the lower limit voltage C and the upper limit voltage D will be described in embodiment 2 described later.

Further, the measurement result of the re-discharge time may be recorded in a histogram, and the superimposed energization start time may be set using the histogram. Fig. 10 is a diagram showing an example of a histogram in which the measurement result of the re-discharge time is recorded. In the histogram, the horizontal axis represents the re-discharge time, which is the V2max period starting from the falling period S of the ignition signal SA, and the vertical axis represents the number of combustion cycles of the internal combustion engine 100 measured for each value of the V2max period, i.e., the frequency of each measurement result representing the re-discharge time.

Even in the histogram shown in fig. 10, the overlapping energization start time can be set by the same method as the scatter chart of fig. 9. That is, line segments 95 and 96 corresponding to the rising timing a and the falling timing B of the ignition signal SB are set, and the interval between the line segment 95 and the line segment 96 is fixed so as to match the energization period of the sub-primary coil 360 that is allowable in terms of heat generation, in accordance with the rotation speed of the internal combustion engine 100. In this state, the line segments 95 and 96 are moved laterally on the histogram, and a position where the total value (frequency) of the number of combustion cycles between the line segment 95 and the line segment 96 is the maximum is searched for. The overlap energization start time can be set based on the position of the line segment 95 thus searched. In addition, when there is no problem in the heat generation of the ignition coil 300, all the regions of the histogram distribution may be set to overlap the energization start times.

Although the above describes the method of setting the superimposed energization start time when the measurement result of the redischarging time is recorded using the scatter chart of fig. 9 and the histogram of fig. 10, the superimposed energization start time may be set in the same manner as in fig. 9 and 10 when the measurement result of the redischarging time is recorded using another method. That is, it is preferable to set the overlap energization start time so that the number of generation times of the re-discharge within a predetermined overlap energization period becomes maximum in the distribution of the measurement results of the re-discharge time recorded by an arbitrary method.

Fig. 11 is a diagram showing an example of a timing chart for explaining a relationship between a control signal input to an ignition coil and an output in the discharge control according to embodiment 1 of the present invention. Fig. 11 is a timing chart showing an example of discharging the ignition plug 200 when the gas is at a high flow rate by using the ignition coil 300 of the present embodiment. Fig. 11 shows a relationship among an ignition signal SA output from the ignition control section 83, a main primary current I1 flowing through the main primary coil 310 in accordance with the ignition signal SA, an ignition signal SB output from the phase control section 380, a sub primary current I3 flowing through the sub primary coil 360 in accordance with the ignition signal SB, electric energy E stored in the ignition coil 300, a secondary current I2 flowing through the secondary side coil 320, and a secondary voltage V2 generated in the secondary side coil 320.

When the ignition signal SA becomes HIGH, the igniter 340 energizes the main primary side coil 310, and the main primary current I1 rises. During energization of the primary side coil 310, the electric energy E in the ignition coil 300C rises together with time.

Thereafter, when the ignition signal SA becomes LOW at the fall period S, the igniter 340 cuts off the energization of the main primary coil 310. Accordingly, an electromotive force is generated to the secondary side coil 320, and the supply of the electric power E from the ignition coil 300 to the ignition plug 200 is started. When the insulation between the electrodes of the spark plug 200 is broken down, the discharge (capacitive discharge) of the spark plug 200 is started. After the start of the discharge of the ignition plug 200, the electric energy E in the ignition coil 300 decreases together with time, maintaining the discharge (induction discharge) of the ignition plug 200.

The secondary current I2 and the secondary voltage V2 rise substantially when the capacitor discharges. The rise of the secondary current I2 and the secondary voltage V2 generated by the discharge of the capacitor is ended in a short time. When the discharge of the spark plug 200 is started and a discharge path is formed between the electrodes, the secondary current I2 and the secondary voltage V2 respectively sharply decrease. In the subsequent inductive discharge, the secondary current I2 decreases together with time. On the other hand, since the discharge path is elongated with the flow of the gas, the secondary voltage V2 rises with the passage of time. At this time, the magnitude of the secondary current I2 required to maintain the discharge path varies according to the flow rate of the gas existing between the electrodes of the spark plug 200.

The phase control unit 380 turns on the ignition signal SB at a time a when a predetermined overlap energization start time elapses from the start of a fall time S at which the ignition signal SA changes from HIGH to LOW. Thereafter, at a time B when a predetermined overlap energization period elapses from the time a, the ignition signal SB is turned off. As described above, the phase control unit 380 sets the overlap energization start time and the overlap energization period used for the control of the control ignition signal SB in advance. That is, the overlap energization start time is set based on the result of statistical processing of the measurement result of the re-discharge time when the ignition plug 200 is discharged in the cylinder 150. Further, the superimposed energization period is set in advance in accordance with the energization period of the sub-primary coil 360 allowable in heat generation based on the rotation speed of the internal combustion engine 100.

While the phase control section 380 outputs the ignition signal SB to the igniter 350, the high voltage generated in the secondary side coil 320 by the ignition signal SB is applied to the high voltage generated in the secondary side coil 320 by the ignition signal SA. The high voltage is applied to the spark plug 200 (center electrode 210). As a result, the secondary current I2 increases to continue maintaining the discharge path. Therefore, the occurrence of re-discharge (restrike: reignition) accompanying the capacitor discharge is suppressed in the spark plug 200. In the example of fig. 11, the number of times of the first discharge and the second discharge is 1 and 2.

The secondary current I2 when the ignition signal SB is output includes a current flowing through the secondary side coil 320 via the main primary coil 310 and a current flowing through the secondary side coil 320 via the sub-primary coil 360.

Fig. 12 is a diagram illustrating the effect of the present invention. In fig. 12, a signal waveform 501 shows a waveform of an ignition signal SB output by the method described in the above embodiment as an ignition signal for a superimposed current of the present invention. The pulse width of the ignition signal SB in the signal waveform 501, that is, the overlap energization period from the rising period a when the ignition signal SB is on to the falling period B when the ignition signal SB is off is determined in accordance with the rotation speed of the internal combustion engine 100, and when the rotation speed of the internal combustion engine 100 is 2400[ rpm ], for example, the overlap energization period is 0.5[ msec ]. On the other hand, the signal waveform 502 shows the waveforms of the ignition signal SB output in all the re-discharge time ranges that may be generated in the spark plug 200 as the ignition signal for the superimposed current of the comparative example. Current waveforms 503 and 504 show examples of the waveforms of the secondary current I2 flowing in response to the ignition signal SB shown by these signal waveforms 501 and 502, respectively.

The graph 505 shows the relationship between the amount of energy consumption of the ignition coil 300 and the combustion stability of the ignition plug 200 due to the supply of the overlap current corresponding to the ignition signal SB. In this drawing 505, points 506 and 507 show the relationship between the energy consumption of the ignition signal SB and the connection stability in the present invention and the comparative example shown in the signal waveforms 501 and 502, respectively. In addition, a point 508 indicates a relationship between the amount of power consumption and connection stability in the conventional example using the circuit 400C of fig. 6.

Comparing the point 506 with the point 507 shows that the present invention is the same as the comparative example in terms of combustion stability (ignition performance), but the present invention is significantly reduced in terms of energy consumption (heat generation amount) as compared with the comparative example. Further, comparing the point 506 and the point 508, it can be seen that although the energy consumption (heat generation amount) of the present invention is slightly increased as compared with the conventional example, the combustion stability (ignition performance) is greatly improved.

As described above, according to the control method of the ignition coil 300 of the present invention, it is possible to achieve both suppression of power consumption of the ignition coil 300 and suppression of misfire in the ignition plug 200. Therefore, the ignition failure of the gas by the ignition plug 200 can be suppressed while suppressing an increase in the volume and cost of the ignition coil 300.

Embodiment 1: setting flow of overlapping energization start time

Next, a method of setting the superimposed energization start time performed in advance to perform the discharge control will be described. Fig. 13 is an example of a flowchart for explaining a method of setting the overlapping energization start time according to embodiment 1 of the present invention. The processing shown in the flowchart of fig. 13 is performed in a predetermined experimental facility or test facility before the ignition coil 300 mounted on the internal combustion engine 100 is connected to the ignition control unit 83 via the igniters 340 and 350, and the ignition coil 300 starts an actual operation, for example, before the development stage or shipment of the ignition coil 300.

When the spark plug 200 and the ignition coil 300 are mounted at predetermined positions of the internal combustion engine 100 for experiment, the circuit 400 of fig. 8 is configured, and the measurement of the secondary voltage V2 is ready, the processing flow of fig. 13 is started in step S101.

In step S102, secondary voltage V2 when ignition signal SA is output from ignition control unit 83 to ignition coil 300 to discharge spark plug 200 is detected.

In step S103, the time differential value dV2/dt of the secondary voltage V2 is calculated and compared with a predetermined threshold value. When dV2/dt exceeds the threshold value, it is determined that the discharge path formed between the electrodes of spark plug 200 is blown out and a re-discharge has occurred, and the process proceeds to step S104. On the other hand, if dV2/dt does not exceed the threshold value, the process returns to step S102 to continue detecting the secondary voltage V2.

In the present embodiment, it is detected that the discharge path formed between the electrodes of the spark plug 200 is blown out and the re-discharge is generated based on the time derivative dV2/dt of the secondary voltage V2 by the processing of step S103. Therefore, as compared with the case of detecting the occurrence of the re-discharge based on the primary voltage V1, it is possible to directly determine whether or not the re-discharge is present from the voltage between the electrodes of the spark plug 200, and therefore, it is possible to improve the detection accuracy. Although the occurrence of the re-discharge can be detected based on the secondary current I2, as shown in fig. 7, the change in the secondary current I2 due to the re-discharge of the spark plug 200 occurs instantaneously in a short time. Therefore, as described above, by detecting the re-discharge of the spark plug 200 based on the time derivative dV2/dt of the secondary voltage V2, more reliable detection can be performed.

When the time derivative dV2/dt of the secondary voltage V2 exceeds the threshold value, the value of the secondary voltage V2 in a certain period before and after the exceeding time point is recorded in step S104, and the maximum point is detected therefrom. Therefore, the timing immediately before the re-discharge between the electrodes of the spark plug 200 can be detected.

In step S105, the generation timing of the local maximum point detected in step S104 is recorded as the local maximum timing.

In step S106, it is determined whether or not a predetermined number of measurement results have been obtained in the processing of steps S101 to S105 performed so far. Here, it is determined whether or not the measurement result of a predetermined number of samples is obtained from the viewpoint of statistics or the like, and when the measurement result is obtained, the process proceeds to step S107. On the other hand, if the predetermined number of measurement results are not obtained, the process returns to step S102 to continue detecting the secondary voltage V2.

In step S107, a maximum time period histogram recorded in step S105 performed so far is created. Here, for example, the scatter diagram shown in fig. 9 and the histogram shown in fig. 10 may be created as the histogram of the maximum period.

In step S108, the interval between the rising timing a and the falling timing B of the ignition signal SB is set for the profile created in step S107. Here, as described above, the interval between the rising period a and the falling period B on the map is fixed to match the energization period of the sub primary coil 360 allowable in heat generation according to the rotation speed of the internal combustion engine 100.

In step S109, in the histogram created in step S107, the rising period a and the falling period B in which the total number of times of the maximum period recorded in the range of the fixed interval set in step S108 is the maximum are specified.

In step S110, the overlap energization start time is set based on the rise time a and the fall time B determined in step S109.

When the overlap energization start time can be set by the above-described processing, the processing flow of fig. 13 is ended in step S111.

The processing of fig. 13 is preferably executed for each operating state of the internal combustion engine 100. For example, a plurality of measurement target values are set for the engine speed, and the processing of fig. 13 is performed for each measurement target value. In this way, the overlap energization start time can be set for each operation state of the internal combustion engine 100.

Embodiment 1: discharge control flow of the sub-primary coil ]

Next, a control method of the sub-primary coil 360 by the phase control section 380 when the above-described discharge control is performed will be described. Fig. 14 is an example of a flowchart for explaining a method of controlling the sub-primary coil 360 by the phase control unit 380 according to embodiment 1 of the present invention. In the present embodiment, when the ignition switch of the vehicle is turned on and the power supply of the internal combustion engine 100 is turned on, the phase control section 380 starts the control of the sub-primary coil 360 according to the flowchart of fig. 14. The processing shown in the flowchart of fig. 14 represents processing corresponding to one cycle of the internal combustion engine 100, and the phase control unit 380 performs the processing shown in the flowchart of fig. 14 for each cycle.

In step S201, the phase control unit 380 starts the processing shown in the flowchart of fig. 14.

In step S202, the phase control unit 380 selects the superimposition energization start time. Here, the overlap energization start timing corresponding to the operating state of the internal combustion engine 100, for example, the engine speed is selected using predetermined map information or the like. The map information used here indicates the overlap energization start time for each operation state of the internal combustion engine 100, and is set in advance by the processing of fig. 13.

In step S203, the phase control unit 380 determines whether or not the ignition signal SA has changed from HIGH to LOW. As described above, the ignition control unit 83 starts outputting the ignition signal SA at a predetermined timing and then stops outputting the ignition signal SA at the predetermined timing. Accordingly, the main primary coil 310 starts to supply the electric energy E to the spark plug 200, and starts the discharge of the spark plug 200. Phase control unit 380 can detect the discharge start timing of spark plug 200 by detecting the fall timing S of ignition signal SA at this time in step S203.

In step S210, the phase control unit 380 measures the elapsed time from the point of time to the present time, starting from the fall time S of the ignition signal SA detected in step S203.

In step S211, the phase control unit 380 compares the overlap energization start time selected in step S202 with the elapsed time measured in step S210 to determine whether the overlap energization start time has elapsed from the fall time S of the ignition signal SA. If the elapsed time is less than the overlap conduction start time, it is determined that the overlap conduction start time has not elapsed, and the process returns to step S210 to continue measuring the elapsed time. On the other hand, if the elapsed time is equal to or longer than the superimposed energization start time, it is determined that the superimposed energization start time has elapsed, and the process proceeds to step S220.

In step S220, the phase control unit 380 turns on the ignition signal SB and starts outputting the ignition signal SB. Therefore, at the rising period a of the ignition signal SB, the superimposed current starts to be supplied from the sub-primary coil 360 to the ignition plug 200.

In step S221, the phase control unit 380 compares the elapsed time from the time point to the present with a predetermined overlap energization period, starting from the rise time a of the ignition signal SB determined by the processing performed in step S220. Further, as described above, the overlap energization period for comparison here is set in advance in accordance with the energization period of the sub-primary coil 360 allowable in heat generation based on the rotation speed of the internal combustion engine 100. As a result, when the elapsed time is shorter than the superimposed conduction period, it is determined that the superimposed conduction period has not elapsed, and the determination in step S221 is continued. On the other hand, if the elapsed time is equal to or longer than the superimposed power-on period, it is determined that the superimposed power-on period has elapsed, and the process proceeds to step S222.

In step S222, the phase control unit 380 turns off the ignition signal SB and stops outputting the ignition signal SB. Therefore, during the falling period B of the ignition signal SB, the supply of the overlap current from the secondary primary coil 360 to the spark plug 200 is stopped.

In step S223, the phase control unit 380 ends the processing shown in the flowchart of fig. 14.

According to embodiment 1 of the present invention described above, the following operational effects are exhibited.

(1) The control device 1, which is an electronic control device, controls the supply of electric energy from the ignition coil 300 to the ignition plug 200 that discharges in the cylinder 150 of the internal combustion engine 100 by controlling the energization of the ignition coil 300 including the primary coil 310 and the secondary primary coil 360 that are respectively disposed on the primary side and the secondary coil 320 that is disposed on the secondary side. The control device 1 controls the energization of the ignition coil 300 by the phase control unit 380 such that the energization of the sub-primary coil 360 is started when a predetermined lap energization start time elapses from the start of discharge of the main primary coil 310 (yes in step S211) (step S220), and the energization of the sub-primary coil 360 is ended when a predetermined lap energization period corresponding to the rotation speed of the internal combustion engine 100 elapses from the start of energization of the sub-primary coil 360 (yes in step S221) (step S222). Therefore, it is possible to achieve both the improvement of fuel efficiency of the internal combustion engine 100 and the suppression of the ignition failure of the ignition plug 200 with respect to the fuel while suppressing the increase in the volume and cost of the ignition coil 300.

(2) The overlap energization start time is determined based on the measurement result of the re-discharge time indicating the time from the start of discharge to the re-discharge when the ignition plug 200 is discharged in the cylinder 150 of the internal combustion engine 100. Specifically, the overlap energization start time is determined by the processing of fig. 13 such that the number of times of occurrence of the re-discharge in a predetermined overlap energization period is maximized in the distribution of the measurement results when the re-discharge time is measured a plurality of times (steps S109 and S110). Therefore, the energization start timing of the secondary primary coil 360 can be appropriately determined so as to achieve both improvement in fuel efficiency of the internal combustion engine 100 and suppression of ignition failure of the fuel by the ignition plug 200.

(3) In the measurement of the re-discharge time, the generation of the re-discharge may be detected based on the differential value dV2/dt of the secondary voltage when the voltage of the secondary coil 320 is measured as the secondary voltage V2. In this way, when the secondary voltage V2 drops sharply, it is determined that the re-discharge has occurred, and the occurrence of the re-discharge can be easily detected. Therefore, the re-discharge time can be accurately measured.

Embodiment 2: circuit of ignition coil

Next, a circuit 400A including the ignition coil 300 according to embodiment 2 of the present invention will be described.

Fig. 15 is a diagram illustrating a circuit 400A including the ignition coil 300 according to embodiment 2 of the present invention. In the present embodiment, the ignition coil 300 has the same configuration as that of fig. 8 described in embodiment 1. That is, the ignition coil 300 of the present embodiment is also configured to include two types of primary coils 310 and 360 (a main primary coil 310 and a sub-primary coil 360) wound with a predetermined number of turns, respectively, and a secondary coil 320 wound with a larger number of turns than the primary coils 310 and 360.

In the present embodiment, the circuit 400A is different from the circuit 400 described in embodiment 1 in that the voltage detection unit 370 is provided between the secondary coil 320 and the spark plug 200. The voltage detection section 370 detects the secondary voltage V2 and transmits the value to the ignition control section 83.

In the present embodiment, the phase control unit 380 compares the secondary voltage V2 detected by the voltage detection unit 370 with a predetermined overlap energization voltage range. The overlap energization voltage range is set based on the result of measuring the occurrence of the re-discharge when the ignition plug 200 is discharged in the cylinder 150 of the internal combustion engine 100 at the development stage of the ignition control unit 83, similarly to the overlap energization start timing described in embodiment 1. Specifically, for example, in the scatter diagram of fig. 9 described in embodiment 1, the lower limit voltage C and the upper limit voltage D of the secondary voltage V2 are set as described above, and the voltage range between the lower limit voltage C and the upper limit voltage D is set as the overlapping energization voltage range.

When the occurrence of the re-discharge is recorded by another method, the overlapping energization voltage range may be set in the same manner. The lower limit voltage and the upper limit voltage overlapping the energization voltage range can be set so that the number of generation times of the re-discharge within the specified voltage range is maximized in the measurement result distribution of the re-discharge voltage recorded by an arbitrary method, that is, the secondary voltage V2 at the time point immediately before the generation of the re-discharge.

As a result of comparing the secondary voltage V2 with the overlap energization voltage range, when the secondary voltage V2 is within the overlap energization voltage range and the re-discharge of the ignition plug 200 is generated, the phase control section 380 outputs the ignition signal SB in the same manner as described in embodiment 1. Therefore, an overlap current is supplied from the sub-primary coil 360 to the spark plug 200 to suppress generation of a re-discharge (restrike: re-ignition) in the spark plug 200 accompanying the discharge of the capacitance. On the other hand, when the secondary voltage V2 is outside the overlap energization voltage range and the re-discharge of the ignition plug 200 occurs, the phase control unit 380 does not output the ignition signal SB. Therefore, when there is a low possibility of occurrence of re-discharge in the spark plug 200, the supply of the superimposed current from the secondary primary coil 360 to the spark plug 200 is stopped to suppress power consumption.

Embodiment 2: setting flow of overlapping energization start time and overlapping energization voltage range ]

Next, a method of setting the overlap energization start time and the overlap energization voltage range, which is performed in advance to perform the discharge control, will be described. Fig. 16 is an example of a flowchart illustrating a method of setting the overlapping conduction start time and the overlapping conduction voltage range according to embodiment 2 of the present invention. In the flowchart of fig. 16, the steps for executing the processing common to the flowchart of fig. 13 described in embodiment 1 are assigned the same step numbers as those in fig. 13. The following description will focus on differences from fig. 13 on the processing shown in the flowchart of fig. 16.

In step S105A, the value and the generation timing of the local maximum point detected in step S104 are recorded as a local maximum value and a local maximum timing, respectively.

In step S107A, a distribution map of the maximum values and the maximum times recorded in step S105A carried out so far is created. Here, for example, the scatter diagram shown in fig. 9 can be made as a distribution diagram of maximum values and maximum times.

In step S108A, the interval between the rising period a and the falling period B of the ignition signal SB and the interval between the lower limit voltage C and the upper limit voltage D are set for the profile created in step S107A. Here, as described above, the interval of the rising period a and the falling period B on the profile is fixed in match with the energization period of the sub-primary coil 360 allowable in heat generation, and the interval of the lower limit voltage C and the upper limit voltage D is fixed based on a prescribed condition, such as a requested value of power consumption or the like.

In step S109A, in the histogram created in step S107A, the rising period a and the falling period B in which the total number of maximum periods recorded in the range of the fixed interval set in step S108A is the maximum, and the lower limit voltage C and the upper limit voltage D are determined, respectively.

In step S110A, the overlap energization start time is set based on the rising period a and the falling period B determined in step S109A. Further, the overlap energization voltage range is set based on the lower limit voltage C and the upper limit voltage D determined in step S109A.

When the overlap energization start time and the overlap energization voltage range can be set by the above-described processing, the processing flow of fig. 16 is ended in step S111.

The processing in fig. 16 is also preferably performed for each operating state of the internal combustion engine 100, as in the processing in fig. 13. For example, a plurality of measurement target values are set for the engine speed, and the processing of fig. 16 is performed for each measurement target value. In this way, the overlap energization start time and the overlap energization voltage range can be set for each operation state of the internal combustion engine 100.

Embodiment 2: discharge control flow of the sub-primary coil ]

Next, a control method of the sub-primary coil 360 by the phase control section 380 when the above-described discharge control is performed will be described. Fig. 17 is an example of a flowchart for explaining a method of controlling the sub-primary coil 360 by the phase control unit 380 according to embodiment 2 of the present invention. In the flowchart of fig. 17, the same step numbers as those in fig. 14 are assigned to the respective steps for executing the processing common to the flowchart of fig. 14 described in embodiment 1. The following description will focus on differences from fig. 14 on the processing shown in the flowchart of fig. 17.

In step S211, when the elapsed time from the falling timing S of the ignition signal SA is equal to or longer than the overlap energization start time, it is determined that the overlap energization start time has elapsed, and the process proceeds to step S212.

In step S212, the phase control section 380 acquires the value of the secondary voltage V2 detected by the voltage detection section 370.

In step S213, the phase control unit 380 compares the secondary voltage V2 acquired in step S212 with a preset overlap energization voltage range, and determines whether or not the secondary voltage V2 is within the overlap energization voltage range. In addition, the overlap energization voltage range for comparison with the secondary voltage V2 is set in advance by the processing of fig. 16, and is set for each operation state of the internal combustion engine 100.

If it is determined in step S213 that the secondary voltage V2 is within the overlap energization voltage range, the process proceeds to step S220, and the phase control unit 380 turns on the ignition signal SB and starts outputting the ignition signal SB. Therefore, at the rising period a of the ignition signal SB, the superimposed current starts to be supplied from the sub-primary coil 360 to the ignition plug 200. On the other hand, if it is determined in step S213 that the secondary voltage V2 is outside the overlap energization voltage range, that is, if it is greater than the upper limit voltage D or less than the lower limit voltage C, the phase control unit 380 proceeds to step S223 and ends the processing shown in the flowchart of fig. 17. In this case, the overlap current is not supplied from the sub-primary coil 360 to the spark plug 200.

Embodiment 2 of the present invention described above is (1) E-E, except that in embodiment 1

(3) In addition, the following effects are exhibited.

(4) When the voltage V2 of the secondary coil 320 at the overlap energization start time from the start of discharge of the main primary coil 310 is greater than the predetermined upper limit voltage D or less than the predetermined lower limit voltage C (no in step S213), the control device 1 does not energize the sub-primary coil 360 by the phase control unit 380. Therefore, when there is a low possibility of the occurrence of the re-discharge in the ignition plug 200, the supply of the superimposed current from the secondary primary coil 360 to the ignition plug 200 is stopped, so that the power consumption of the ignition coil 300 can be further suppressed.

(5) The upper limit voltage D and the lower limit voltage C are determined based on the measurement result of the re-discharge voltage indicating the voltage V2 of the secondary coil 320 at the time point immediately before the generation of the re-discharge when the ignition plug 200 is discharged in the cylinder 150 of the internal combustion engine 100. Specifically, in the processing of fig. 16, the upper limit voltage D and the lower limit voltage C are determined so that the number of generation times of the re-discharge is maximized within a predetermined voltage range in the distribution of the measurement results when the re-discharge voltage is measured a plurality of times (steps S109A and S110A). Therefore, the range of the secondary voltage V2 that energizes the secondary primary coil 360 can be appropriately set so that further power consumption of the ignition coil 300 is suppressed while suppressing the ignition failure of the gas by the ignition plug 200.

Embodiment 3: circuit of ignition coil

Next, a circuit 400B including the ignition coil 300 according to embodiment 3 of the present invention will be described.

Fig. 18 is a diagram illustrating a circuit 400B including the ignition coil 300 according to embodiment 3 of the present invention. In the present embodiment, the ignition coil 300 has the same configuration as that of fig. 8 described in embodiment 1. That is, the ignition coil 300 of the present embodiment is also configured to include two types of primary coils 310 and 360 (a main primary coil 310 and a sub-primary coil 360) wound with a predetermined number of turns, respectively, and a secondary coil 320 wound with a larger number of turns than the primary coils 310 and 360.

In this embodiment, a circuit 400B is different from the circuit 400 described in embodiment 1 in that a timer circuit 381 is provided separately from an ignition control section 83, and a phase control section 380 is provided in the timer circuit 381. The timer circuit 381 sets a timer value corresponding to the overlap energization period, and when the ignition signal SB is output by the phase control unit 380 and energization of the sub primary coil 360 is started, the timer circuit 381 counts the elapsed time from the rise time a of the ignition signal SB. When the elapsed time reaches the set timer value, the output of the ignition signal SB is stopped, and the energization of the sub-primary coil 360 is ended. In the present embodiment, the on period of the ignition signal SB is controlled using the function of the timer circuit 381 as described above.

In the present embodiment, timer circuit 381 acquires the on period (charging period of main primary coil 310) or the cycle (discharging cycle of spark plug 200) of ignition signal SA. Then, the timer value is set based on these acquired values. For example, a timer value is set as a value obtained by multiplying the on period or cycle of the ignition signal SA by a predetermined magnification.

Fig. 19 is an example of map information showing a relationship between the engine speed of the internal combustion engine 100 and the on period of the ignition signal SA. As shown in fig. 19, the on period of the ignition signal SA changes according to the engine speed of the internal combustion engine 100.

Fig. 20 is an example of a graph showing a relationship between the on period of the ignition signal SA and the on period of the ignition signal SB. As shown in the graph of fig. 20, the on period of ignition signal SA is set to be shorter as the on period of ignition signal SB is shorter.

Timer circuit 381 utilizes the relationship between the engine speed and the on period of ignition signal SA shown in fig. 19, for example, from the graph of fig. 20, to set a timer value based on the on period of ignition signal SB corresponding to the acquired on period of ignition signal SA. Therefore, the timer value that varies according to the engine rotation speed can be set without using map information that is set in advance for each operating state of the internal combustion engine 100.

In the above description, the example has been described in which the on period of ignition signal SA is controlled by setting the timer value of timer circuit 381 based on the on period of ignition signal SA, using the fact that the on period of ignition signal SA changes according to the engine speed of internal combustion engine 100, but the cycle of ignition signal SA, that is, the discharge cycle of spark plug 200 may be controlled similarly. I.e., the period of the ignition signal SA, varies according to the engine speed of the internal combustion engine 100. Therefore, it is also possible to use this point to set the timer value of the timer circuit 381 based on the cycle of the ignition signal SA so as to control the on period of the ignition signal SB. Even in this case, the timer value that changes in accordance with the engine speed can be set without using map information that is set in advance for each operating state of the internal combustion engine 100.

Embodiment 3: discharge control flow of the sub-primary coil ]

Next, a control method of the sub-primary coil 360 by the phase control section 380 and the timer circuit 381 when the above-described discharge control is carried out will be described. Fig. 21 is an example of a flowchart illustrating a method of controlling the sub-primary coil 360 by the phase control unit 380 and the timer circuit 381 according to embodiment 3 of the present invention. In the flowchart of fig. 21, the steps for executing the processing common to the flowchart of fig. 14 described in embodiment 1 are assigned the same step numbers as those in fig. 14. The following description will focus on differences from fig. 14 on the processing shown in the flowchart of fig. 21.

When the processing shown in the flowchart of fig. 21 is started in step S201, the phase control unit 380 selects the superimposition energization start time in step S202. Here, the overlap energization start time corresponding to the operating state of the internal combustion engine 100, for example, the engine speed is selected using information set in advance in the same manner as in embodiment 1.

When it is determined in step S203 that the ignition signal SA changes from HIGH to LOW, the timer circuit 381 acquires the on period of the ignition signal SA in the next step S204. Here, for example, the on period of the ignition signal SA is acquired by acquiring a predetermined monitor signal output in synchronization with the ignition signal SA from the ignition control unit 83.

In step S205, the timer circuit 381 sets a timer value based on the on period of the ignition signal SA obtained in step S204. Here, for example, a value obtained by multiplying the on period of the ignition signal SA by a predetermined magnification is set as the timer value.

As described above, when the timer value of the timer circuit 381 is set based on the cycle of the ignition signal SA, the timer value may be set by acquiring the cycle in step S204 instead of the on period of the ignition signal SA and performing the process of step S205 based on the cycle.

The timer value set in step S205 is used for the determination in step S221. That is, in the present embodiment, in step S221, the timer circuit 381 compares the elapsed time counted from the turning on of the ignition signal SB in step S220 with the timer value set in step S205. As a result, when the elapsed time is smaller than the timer value, it is determined that the superimposition energization period has not elapsed, and the determination at step S221 is continued. On the other hand, when the elapsed time reaches the timer value, it is determined that the superimposed power-on period has elapsed, and the process proceeds to step S222.

According to embodiment 3 of the present invention described above, the following operational effects are exhibited in addition to (1) to (3) described in embodiment 1.

(6) The control device 1 includes a timer circuit 381, and the timer circuit 381 sets a timer value corresponding to the overlap energization period, and terminates energization of the sub-primary coil 360 when an elapsed time from the start of energization of the sub-primary coil 360 reaches the timer value. Therefore, the energization control of the secondary primary coil 360 reflecting the operating state of the internal combustion engine 100 can be performed without using map information set in advance for each operating state of the internal combustion engine 100.

(7) The timer circuit 381 sets a timer value based on the charging period of the main primary coil 310 or the discharging period of the ignition plug 200. Therefore, the timer value can be set so that the energization period of the sub primary winding 360 is appropriately changed in accordance with the engine speed.

[ embodiment 4]

Next, embodiment 4 of the present invention will be described, and in this embodiment, an example will be described in which the circuit 400A described in embodiment 2 is used to correct the superimposed energization start time corresponding to the gas flow rate between the electrodes during discharge of the spark plug 200.

Fig. 22 is a diagram showing an example of a timing chart for explaining a relationship between a control signal input to an ignition coil and an output in the discharge control according to embodiment 4 of the present invention. In the present embodiment, as shown in the timing chart of fig. 22, the values of the secondary voltage V2 at the times T1 and T2 are acquired in the discharge period after the falling time S of the ignition signal SA in the ignition plug 200. Then, from the acquired values of the secondary voltages V2, the slope of the graph showing the temporal change of the secondary voltage V2 is obtained, and the superimposition energization start time is adjusted based on the magnitude of the slope. For example, the lap energization start time can be adjusted by setting a preset lap energization start time as a reference value and adding a correction value corresponding to a temporal change of the secondary voltage V2 thereto.

The secondary voltage V2 of the spark plug 200 during discharge varies according to the gas flow rate between the electrodes. Therefore, as described above, by obtaining the slope of the graph showing the temporal change in the secondary voltage V2 and changing the overlap energization start time in accordance with the magnitude of the slope, the time interval from the fall time S of the ignition signal SA to the rise time a of the ignition signal SB can be adjusted in accordance with the gas flow rate between the electrodes. Therefore, the overlap energization start timing corresponding to the gas flow rate between the electrodes during discharge of the spark plug 200 can be corrected.

Fig. 23 is an example of a graph showing a relationship between the gas flow rate between the electrodes (time change of the secondary voltage V2) and the corrected addition value to the rise time a of the ignition signal SB. As shown in the graph of fig. 23, the gas flow velocity between the electrodes becomes a high flow velocity, and the time change of the secondary voltage V2 becomes larger accordingly, the correction addition value with respect to the rise period a is set smaller, thereby performing correction so that the rise period a of the ignition signal SB is advanced. As a result, the overlap energization start time can be shortened, and the energization period of the secondary primary coil 360 can be adjusted according to the gas flow rate.

Embodiment 4: discharge control flow of the sub-primary coil

Next, a control method of the sub-primary coil 360 by the phase control section 380 when the above-described discharge control is performed will be described. Fig. 24 is an example of a flowchart for explaining a method of controlling the sub-primary winding 360 by the phase control unit 380 according to embodiment 4 of the present invention. In the flowchart of fig. 24, the same step numbers as those in fig. 14 are assigned to the respective steps of executing the processing common to the flowchart of fig. 14 described in embodiment 1. The following description will focus on differences from fig. 14 on the processing shown in the flowchart of fig. 24.

When the processing shown in the flowchart of fig. 24 is started in step S201, the phase control unit 380 selects the superimposition energization start time in step S202. Here, the overlap energization start time corresponding to the operating state of the internal combustion engine 100, for example, the engine speed is selected using information set in advance in the same manner as in embodiment 1.

When it is determined in step S203 that the ignition signal SA has changed from HIGH to LOW, the phase control unit 380 acquires the value of the secondary voltage V2 detected by the voltage detection unit 370 in the next step S206.

In step S207, the phase control section 380 estimates the gas flow rate between the electrodes of the spark plug 200 based on the secondary voltage V2 acquired in step S206. Here, as described above, the slope of the secondary voltage V2 is obtained based on the values of the secondary voltage V2 acquired at the present time and the period immediately before the present time, and the gas flow rate between the electrodes is estimated from the magnitude of the slope. In addition, only the value of one secondary voltage V2 is still acquired, and therefore in the case where the slope of the secondary voltage V2 cannot be calculated, the process of step S207 may be omitted.

In step S208, the phase control unit 380 corrects the superimposing energization start timing selected in step S202 based on the gas flow rate estimated in step S207. Here, for example, the correction addition value is determined based on the relationship between the gas flow rate between the electrodes and the correction addition value for the rise period a of the ignition signal SB shown in fig. 23, and the overlap energization start time is corrected by adding the correction addition value. Therefore, the overlap energization start time is varied based on the temporal variation of the secondary voltage V2 corresponding to the variation of the gas flow rate.

The lap energization start time corrected in step S208 is used for the determination in step S211. That is, in the present embodiment, in step S211, the phase control unit 380 compares the superimposed energization start time corrected in step S208 with the elapsed time measured in step S210 to determine whether or not the superimposed energization start time has elapsed from the fall time S of the ignition signal SA. As a result, when the elapsed time is less than the superimposed conduction start time, it is determined that the superimposed conduction start time has not elapsed, and the process returns to step S206, where the superimposed conduction start time and the measured elapsed time are continuously corrected based on the temporal change in the secondary voltage V2. On the other hand, if the elapsed time is equal to or longer than the superimposed energization start time, it is determined that the superimposed energization start time has elapsed, and the process proceeds to step S220.

According to embodiment 4 of the present invention described above, the following operational effects are exhibited in addition to (1) to (3) described in embodiment 1.

(8) In the control device 1, the phase control unit 380 changes the lap energization start time based on the time change of the voltage V2 of the secondary coil 320 (steps 206 to S208). Thereby, the energization period of the secondary primary coil 360 can be adjusted according to the gas flow rate between the electrodes in the spark plug 200. Therefore, even when the operating state of the internal combustion engine 100 varies with each combustion cycle, the ignition failure of the gas by the ignition plug 200 can be reliably suppressed. This applies not only to a series hybrid type electric vehicle that drives a generator motor by the internal combustion engine 100 and uses its electric power to drive a drive motor, but also to a conventional vehicle that drives a vehicle by the internal combustion engine 100 or a parallel hybrid type electric vehicle.

[ modification ]

In embodiments 1 to 4 described above, the control device 1 can increase the overlap energization start time by lengthening the period from the falling timing S of the ignition signal SA to the rising timing a of the ignition signal SB as the phase control unit 380 increases the discharge start timing of the main primary coil 310, that is, the falling timing S of the ignition signal SA, in accordance with the operating state of the internal combustion engine 100. Thus, when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100, the ignition signal SB can be output so that the superimposed current can be supplied from the sub-primary coil 360 to the spark plug 200 at the timing when the tumble flow is generated in the gas in the cylinder 150 (tumble collapse). Therefore, blow-out of the discharge path due to tumble collapse can be effectively suppressed, and the ignitability of the spark plug 200 against gas can be improved.

In the embodiments described above, the functional configurations of the control device 1 described in fig. 3 may be realized by software executed by the MPU50 as described above, or may be realized by hardware such as an FPGA (Field-Programmable Gate Array). Further, they may be used in combination.

The above-described embodiments 1 to 4 can be applied individually or in any combination of two or more. Further, one of them may be selectively applied based on the operating conditions of the internal combustion engine 100 and the like.

The embodiments and the modifications described above are merely examples, and the present invention is not limited to these embodiments as long as the features of the present invention are not impaired. Although the various embodiments and modifications have been described above, the present invention is not limited to these. Other ways that can be considered within the scope of the technical idea of the present invention are also included within the scope of the present invention.

Description of the reference symbols

1 control device

10 analog input unit

20 digit input part

30A/D conversion part

40RAM

50MPU

60ROM

70I/O port

80 output circuit

81 overall control section

82 fuel injection control part

83 ignition control part

84 cylinder discriminating part

85 degree information generating part

86 revolution speed information generating part

87 intake air amount measuring part

88 load information generating part

89 water temperature measuring part

100 internal combustion engine

110 air purifier

111 air inlet pipe

112 intake manifold

113 throttle valve

113a throttle opening sensor

114 flow sensor

115 temperature sensor for intake air

120 ring gear

121 crank angle sensor,

122 water temperature sensor

123 crankshaft

125 Accelerator pedal

126 throttle position sensor

130 fuel tank

131 fuel pump

132 pressure regulator

133 fuel piping

134 fuel injection valve

140 combustion pressure sensor

150 cylinder

151 air inlet 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. 300C ignition coil

310 primary coil

320 secondary side coil

330 DC power supply

340. 350 igniter

360 pairs of primary coils

370 voltage detecting part

380 phase control part

381 timer circuit

390 resistor

400. 400A, 400B, 400C.

Claims (12)

1. An electronic control device for controlling supply of electric energy from an ignition coil to an ignition plug for discharging electric energy into a cylinder of an internal combustion engine by controlling energization of the ignition coil, the ignition coil including a main primary coil and a sub primary coil arranged on a primary side, respectively, and a secondary coil arranged on a secondary side, the electronic control device being characterized in that,

the energization of the ignition coil is controlled such that the energization of the sub-primary coil is started when a predetermined overlap energization start time has elapsed after the discharge of the main primary coil is started, and the energization of the sub-primary coil is ended when a predetermined overlap energization period corresponding to the rotation speed of the internal combustion engine has elapsed after the energization of the sub-primary coil is started.

2. The electronic control device according to claim 1,

the overlap energization start time is determined based on a measurement result of a re-discharge time indicating a time from a start of discharge to a re-discharge when the ignition plug is discharged in the cylinder of the internal combustion engine.

3. The electronic control device of claim 2,

the overlap energization start time is determined so that the number of times of occurrence of the re-discharge in the overlap energization period becomes maximum in a distribution of the measurement results when the re-discharge time is measured a plurality of times.

4. The electronic control device according to claim 3,

in the measurement of the re-discharge time, the generation of the re-discharge is detected based on a differential value of the secondary voltage when the voltage of the secondary coil is measured as the secondary voltage.

5. The electronic control device according to any one of claims 1 to 4,

when the voltage of the secondary coil is greater than a predetermined upper limit voltage or less than a predetermined lower limit voltage after the overlap energization start time has elapsed after the discharge of the main primary coil is started, the energization of the sub-primary coil is not performed.

6. The electronic control device of claim 5,

the upper limit voltage and the lower limit voltage are decided based on a measurement result of a re-discharge voltage representing a voltage of the secondary coil at a time point immediately before occurrence of re-discharge when the ignition plug is discharged in the cylinder of the internal combustion engine.

7. The electronic control device according to claim 6,

the upper limit voltage and the lower limit voltage are determined so that the number of times of occurrence of the re-discharge becomes maximum within a predetermined voltage range in a distribution of measurement results when the re-discharge voltage is measured a plurality of times.

8. The electronic control device of claim 1,

the overlap energization period during which the rotational speed of the internal combustion engine is 2400 revolutions per minute is 0.5 msec.

9. The electronic control device according to claim 1,

the secondary primary winding includes a timer circuit that sets a timer value corresponding to the overlap energization period, and ends energization of the secondary primary winding when an elapsed time after energization of the secondary primary winding is started reaches the timer value.

10. The electronic control device of claim 9,

the timer circuit sets the timer value based on a charging period of the main primary coil or a discharging period of the ignition plug.

11. The electronic control device according to claim 1,

the overlap energization start time is varied based on a time variation of a voltage of the secondary coil.

12. An electronic control device for controlling supply of electric energy from an ignition coil to an ignition plug for discharging electric energy from the ignition coil into a cylinder of an internal combustion engine by controlling energization of the ignition coil, the ignition coil including a main primary coil and a sub primary coil arranged on a primary side, respectively, and a secondary coil arranged on a secondary side, the electronic control device being characterized in that,

controlling the energization of the ignition coil such that the energization of the secondary primary coil is started when a predetermined overlap energization start time elapses after the discharge of the primary coil is started, and the energization of the secondary primary coil is ended when a predetermined overlap energization period elapses after the energization of the secondary primary coil is started,

the overlap energization start time is increased as the discharge start timing of the main primary coil becomes earlier according to the operating state of the internal combustion engine.

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