WO2022018986A1 - Electronic control device - Google Patents

Abstract

This electronic control device controls energization of ignition coils including a main primary coil and an auxiliary primary coil each disposed on a primary side and a secondary coil disposed on a secondary side, and, as a result, controls supply of electric energy from the ignition coils to an ignition plug for generating an electric discharge in a cylinder of an internal combustion engine. The energization of the ignition coils is controlled such that after the elapse of a predetermined superimposing-energization start time from the start of discharging the main primary coil, energization of the auxiliary primary coil is started, and after the elapse of a predetermined superimposing-energization time period according to the rotation speed of the internal combustion engine from the start of energization of the auxiliary primary coil, energization of the auxiliary primary coil is ended.

Description

Electronic control device

The present invention relates to an electronic control device.

In recent years, in order to improve the fuel efficiency of vehicles, an internal combustion engine that has introduced a technology to operate an internal combustion engine by burning an air-fuel mixture thinner than the stoichiometric air-fuel ratio and a technology to take in a part of the exhaust gas after combustion and re-intake it. Control device has been developed.

In the control device of this type of internal combustion engine, the amount of fuel and air in the combustion chamber deviates from the theoretical value, so that ignition failure of the fuel by the spark plug is likely to occur. Therefore, by increasing the gas flow velocity in the combustion chamber, the flow velocity between the electrodes of the spark plug is increased so that the discharge path is formed longer, so that the contact length between the discharge path and the gas is lengthened. There is a way to suppress ignition failure. However, when the flow velocity between the electrodes of the spark plug is increased, the frequency of blowout of the discharge path and the occurrence of re-discharge associated therewith increases, and it becomes difficult to form a long discharge path.

In order to form a long discharge path, it is necessary to maintain the discharge path for as long as possible by continuing to supply current with a sufficient amount of current after the discharge path is formed. However, in general, since the internal energy of the ignition coil continues to decrease with the lapse of time from the start of discharge, the ignition coil gradually becomes unable to supply the current required to maintain the discharge path. As a result, the discharge path cannot be maintained during the combustion of the gas, which causes a problem that re-discharge is required.

In Patent Document 1, an ignition coil having a main primary coil and a secondary primary coil is used, and after generating a discharge spark in the spark plug by the main primary coil, the primary voltage and the threshold are compared and the threshold is exceeded. A control device for an internal combustion engine is disclosed in which a current is superimposed by a secondary primary coil for a period of time.

International Publication No. 2019/198119

In the technique disclosed in Patent Document 1, since the energization time of the superimposed current changes according to the magnitude of the primary voltage, the calorific value of the ignition coil fluctuates in each cycle of the internal combustion engine. In order to be able to cope with such cycle fluctuations of the calorific value, it is necessary to set the cooling capacity including an excessive margin for the ignition coil, and the volume and cost of the ignition coil increase accordingly. Occurs.

Therefore, the present invention has been made by paying attention to the above-mentioned problems, and an object thereof is to achieve both improvement of fuel efficiency of an internal combustion engine and suppression of ignition failure of fuel while suppressing an increase in the volume and cost of an ignition coil. And.

The electronic control device according to the first aspect of the present invention energizes an ignition coil including a main primary coil and a sub primary coil arranged on the primary side and a secondary coil arranged on the secondary side, respectively. By controlling the above, the supply of electric energy from the ignition coil to the spark plug discharged in the cylinder of the internal combustion engine is controlled, and a predetermined superimposed energization is performed after the discharge of the main primary coil is started. When the start time elapses, the energization of the sub-primary coil is started, and when a predetermined superimposition energization period according to the rotation speed of the internal combustion engine elapses after the energization of the sub-primary coil is started, the above-mentioned The energization of the ignition coil is controlled so as to end the energization of the secondary primary coil.
The electronic control device according to the second aspect of the present invention energizes an ignition coil including a main primary coil and a sub primary coil arranged on the primary side and a secondary coil arranged on the secondary side, respectively. By controlling, the supply of electric energy from the ignition coil to the ignition plug discharged in the cylinder of the internal combustion engine is controlled, and a predetermined superimposed energization is performed after the discharge of the main primary coil is started. When the start time elapses, the energization of the sub-primary coil is started, and when a predetermined superposition energization period elapses after the energization of the sub-primary coil is started, the energization of the sub-primary coil is terminated. As described above, the energization of the ignition coil is controlled, and the earlier the discharge start timing of the main primary coil is made according to the operating state of the internal combustion engine, the more the superimposition energization start time is increased.

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

It is a figure explaining the main part structure of the internal combustion engine and the control device of the internal combustion engine which concerns on embodiment. It is a partially enlarged view explaining the spark plug. It is a functional block diagram explaining the functional structure of the control device which concerns on embodiment. It is a figure explaining the relationship between the operating state of an internal combustion engine, and the gas flow velocity around a spark plug. It is a figure explaining the relationship between the discharge path and the flow velocity between the electrodes of a spark plug. It is a figure explaining the electric circuit including the conventional ignition coil. It is a figure which shows an example of the timing chart explaining the relationship between the control signal input to the ignition coil and the output in the conventional discharge control. It is a figure explaining the electric circuit including the ignition coil which concerns on 1st Embodiment. It is a figure which shows the example of the scatter diagram which recorded the measurement result of the re-discharge voltage and the re-discharge time. It is a figure which shows the example of the histogram which recorded the measurement result of the re-discharge time. It is a figure which shows an example of the timing chart explaining the relationship between the control signal input to the ignition coil and the output in the discharge control which concerns on 1st Embodiment. It is a figure explaining the effect of this invention. It is an example of the flowchart explaining the setting method of the superimposition energization start time which concerns on 1st Embodiment. It is an example of the flowchart explaining the control method of the secondary primary coil which concerns on 1st Embodiment. It is a figure explaining the electric circuit including the ignition coil which concerns on the 2nd Embodiment. It is an example of the flowchart explaining the setting method of the superimposition energization start time and superimposition energization voltage range which concerns on 2nd Embodiment. It is an example of the flowchart explaining the control method of the secondary primary coil which concerns on 2nd Embodiment. It is a figure explaining the electric circuit including the ignition coil which concerns on 3rd Embodiment. This is an example of map information showing the relationship between the engine speed and the ON period of the ignition signal SA. This is an example of a graph showing the relationship between the ON period of the ignition signal SA and the ON period of the ignition signal SB. It is an example of the flowchart explaining the control method of the secondary primary coil which concerns on 3rd Embodiment. It is a figure which shows an example of the timing chart explaining the relationship between the control signal input to the ignition coil and the output in the discharge control which concerns on 4th Embodiment. This is an example of a graph showing the relationship between the gas flow velocity between the electrodes and the correction addition value for the rise time of the ignition signal SB. It is an example of the flowchart explaining the control method of the secondary primary coil which concerns on 4th Embodiment.

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

Hereinafter, the control device 1 which is one aspect of the electronic control device according to the embodiment of the present invention will be described. In this embodiment, a case where the control device 1 controls the discharge (ignition) of the spark plug 200 provided in each cylinder 150 of the four-cylinder internal combustion engine 100 will be illustrated and described.
Hereinafter, in the embodiment, a combination of a partial configuration or all configurations of the internal combustion engine 100 and a partial configuration or all configurations of the control device 1 is referred to as a control device 1 of the internal combustion engine 100.

[Internal combustion engine]
FIG. 1 is a diagram illustrating a main configuration of an internal combustion engine 100 and an ignition device for an internal combustion engine.
FIG. 2 is a partially enlarged view illustrating electrodes 210 and 220 of the spark plug 200.

In the internal combustion engine 100, the air sucked from the outside passes through the air cleaner 110, the intake pipe 111, and the intake manifold 112, and when the intake valve 151 is opened, it flows into each cylinder 150. 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 rate sensor 114.

The throttle valve 113 is provided with a throttle opening sensor 113a that detects the opening of the throttle. The opening degree information of the throttle valve 113 detected by the throttle opening degree sensor 113a is output to the control device (Electronic Control Unit: ECU) 1.

The throttle valve 113 uses an electronic throttle valve driven by an electric motor, but may be another method 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.

A crank angle sensor 121 is provided on the radial outer side of the ring gear 120 attached to the crankshaft 123. The crank angle sensor 121 detects the rotation angle of the crankshaft 123. In the embodiment, the crank angle sensor 121 detects the rotation angle of the crankshaft 123, for example, every 10 ° and every combustion cycle.

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

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

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

The cylinder head (not shown) of the internal combustion engine 100 is provided with a combustion pressure sensor (CylinderPressure Sensor: CPS, also referred to as an in-cylinder pressure sensor) 140. The combustion pressure sensor 140 is provided in each cylinder 150 and detects the pressure (combustion pressure) in the cylinder 150.

As the combustion pressure sensor 140, a piezoelectric or gauge type pressure sensor is used, and it is possible to detect the combustion pressure (in-cylinder pressure) in the cylinder 150 over a wide temperature range.

Each cylinder 150 is equipped with an exhaust valve 152 and an exhaust manifold 160 that exhausts the gas (exhaust gas) after combustion to the outside of the cylinder 150. A three-way catalyst 161 is provided on the exhaust side of the exhaust manifold 160. When the exhaust valve 152 is opened, exhaust gas is discharged from the cylinder 150 to the exhaust manifold 160. This exhaust gas is purified by the three-way catalyst 161 through the exhaust manifold 160 and then discharged to the atmosphere.

An upstream air-fuel ratio sensor 162 is provided on the upstream side 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 on the downstream side of the three-way catalyst 161. The downstream air-fuel ratio sensor 163 outputs a switch-like detection signal in the vicinity of the theoretical air-fuel ratio. In the embodiment, the downstream air-fuel ratio sensor 163 is, for example, an O2 sensor.

Further, a spark plug 200 is provided on the upper part of each cylinder 150. Due to the discharge (ignition) of the spark plug 200, sparks are ignited in the air-fuel mixture in the cylinder 150, an explosion occurs in the cylinder 150, and the piston 170 is pushed down. When the piston 170 is pushed down, the crankshaft 123 rotates.

The spark plug 200 is connected to an ignition coil 300 that generates electrical energy (voltage) supplied to the spark plug 200. The voltage generated by the ignition coil 300 causes a discharge 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 by the insulator 230 in an insulated state. A predetermined voltage (for example, 20,000V to 40,000V in the 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) occurs between the center electrode 210 and the outer electrode 220.

In the spark plug 200, the voltage at which discharge (ignition) occurs due to dielectric breakdown of the gas component fluctuates depending on the state of the gas (gas) existing between the center electrode 210 and the outer electrode 220 and the in-cylinder pressure. .. The voltage at which this discharge occurs is called the breakdown voltage.

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

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

[Hardware configuration of controller]
Next, the overall configuration 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) conversion unit 30, a RAM (Random Access Memory) 40, and an MPU (Micro-). It has a Processing Unit) 50, a ROM (Read Only Memory) 60, an I / O (Input / Output) port 70, and an output circuit 80.

The analog input unit 10 is provided with various sensors such as a throttle opening sensor 113a, a flow rate sensor 114, an accelerator position sensor 126, an upstream air fuel ratio sensor 162, a downstream air fuel ratio sensor 163, a combustion pressure sensor 140, and a water temperature sensor 122. An analog output signal is input.

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

A digital output signal from the crank angle sensor 121 is input to the digital input unit 20.

An I / O port 70 is connected to the digital input unit 20, and the digital output signal input to the digital input unit 20 is stored in the RAM 40 via the I / O port 70.

Each output signal stored in the RAM 40 is arithmetically processed by the MPU 50.

The MPU 50 executes a control program (not shown) stored in the ROM 60 to perform arithmetic processing on the output signal stored in the RAM 40 according to the control program. The MPU 50 calculates a control value that defines the operating amount of each actuator (for example, throttle valve 113, pressure regulator 132, spark plug 200, etc.) that drives the internal combustion engine 100 according to a control program, and temporarily stores it in the RAM 40. ..

The control value that defines the operating amount of the actuator stored in the RAM 40 is output to the output circuit 80 via the I / O port 70.

The output circuit 80 is provided with a function of an ignition control unit 83 (see FIG. 3) that controls a voltage applied to the spark plug 200.

[Control device functional block]
Next, the functional configuration of the control device 1 according to the embodiment of the present invention will be described.

FIG. 3 is a functional block diagram illustrating the functional configuration of the control device 1 according to the embodiment of the present invention. Each function of the control device 1 is realized in the output circuit 80, for example, by the MPU 50 executing a control program stored in the ROM 60.

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

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

The overall control unit 81 controls the fuel injection control unit 82 and the ignition control unit 83 as a whole based on the required torque (acceleration signal S1) from the accelerator position sensor 126 and the output signal S2 from the combustion pressure sensor 140. I do.

The fuel injection control unit 82 includes a cylinder discrimination unit 84 that discriminates each cylinder 150 of the internal combustion engine 100, an angle information generation unit 85 that measures the crank angle of the crankshaft 123, and a rotation speed information generation unit that measures the engine rotation speed. The cylinder discrimination information S3 from the cylinder discrimination unit 84, the crank angle information S4 from the angle information generation unit 85, and the engine rotation speed information S5 from the rotation speed information generation unit 86 are connected to the 86. accept.

Further, the fuel injection control unit 82 measures the temperature of the engine cooling water, the intake amount measuring unit 87 that measures the intake amount of the air taken into the cylinder 150, the load information generation unit 88 that measures the engine load, and the engine cooling water. Connected to the water temperature measuring unit 89, the intake air amount information S6 from the intake air amount measuring unit 87, the engine load information S7 from the load information generation unit 88, and the cooling water temperature information S8 from the water temperature measuring unit 89. , Is accepted.

The fuel injection control unit 82 calculates the injection amount and injection time of the fuel injected from the fuel injection valve 134 (fuel injection valve control information S9) based on each received information, and the calculated fuel injection amount and injection. The fuel injection valve 134 is controlled based on the time.

The ignition control unit 83 is connected to the cylinder discrimination 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. We accept each information from these.

Based on each received information, the ignition control unit 83 energizes the primary side coil (not shown) of the ignition coil 300 with the current amount (energization angle), the energization start time, and the primary side coil. Calculate the time to cut off the current (ignition time).

The ignition control unit 83 outputs an ignition signal SA to the primary coil of the ignition coil 300 based on the calculated energization angle, the energization start time, and the ignition time, thereby controlling the discharge (ignition) by the spark plug 200. Control).

At least, the function of the ignition control unit 83 to control the ignition of the spark plug 200 by using the ignition signal SA corresponds to the control device for an internal combustion engine of the present invention.

FIG. 4 is a diagram illustrating the relationship between the operating state of the internal combustion engine 100 and the gas flow velocity around the spark plug 200. As shown in FIG. 4, generally, the higher the engine speed and the load, the higher the gas flow rate in the cylinder 150, and the higher the gas flow rate around the spark plug 200. Therefore, the gas flows at high speed between the center electrode 210 and the outer electrode 220 of the spark plug 200. Further, in the internal combustion engine 100 in which exhaust gas recirculation (EGR: Exhaust Gas Recirculation) is performed, the EGR rate is set, for example, as shown in FIG. 4, according to the relationship between the engine rotation speed and the load. It should be noted that the larger the high EGR region in which the EGR rate is set higher, the lower the fuel consumption and the lower the exhaust gas, but the ignition failure is likely to occur in the spark plug 200.

FIG. 5 is a diagram illustrating the relationship between the discharge path and the flow velocity between the electrodes of the spark plug 200. When a high voltage is generated in the secondary side coil of the spark plug 300 and dielectric breakdown occurs between the center electrode 210 and the outer electrode 220 of the spark plug 200, the current flowing between these electrodes becomes a constant value or less. Meanwhile, a discharge path is formed between the electrodes of the spark plug 200. When combustible gas comes into contact with this discharge path, flame nuclei grow and lead to combustion. Since the discharge path moves under the influence of the gas flow between the electrodes, the higher the gas flow velocity, the longer the discharge path is formed, and the lower the gas flow velocity, the shorter the discharge path. FIG. 5A shows an example of the discharge path 211 when the gas flow velocity is high, and FIG. 5B shows an example of the discharge path 212 when the gas flow velocity is low.

When the internal combustion engine 100 is operated at a high EGR rate, the probability that the flame nucleus grows even if the combustible gas comes into contact with the discharge path decreases, so it is necessary to increase the chances that the combustible gas comes into contact with the discharge path. As described above, since the discharge path is generated by breaking the insulation of the gas, if the current required to maintain the discharge path is constant, it is necessary to output electric power according to the length of the discharge path. Therefore, when the gas flow velocity is high, the energization control of the ignition coil 300 is performed so that a large amount of electric power is output from the ignition coil 300 to the spark plug 200 in a short time, whereby the long discharge path as shown in FIG. 5A is performed. It is preferable to form 211 to obtain contact opportunities with gas in a wider space. On the other hand, when the gas flow velocity is low, the energization control of the ignition coil 300 is performed so that a small amount of power is continuously output from the ignition coil 300 to the spark plug 200 for a long period of time, whereby the short power as shown in FIG. 5 (b) is controlled. By maintaining the formation of the discharge path 212, it is preferable to obtain a contact opportunity with the gas passing near the electrode of the spark plug 200 for a longer period of time.

[Electric circuit of conventional ignition coil]
Next, before explaining the embodiment of the present invention, the conventional ignition coil will be described.

FIG. 6 is a diagram illustrating an electric circuit 400C including a conventional ignition coil 300C as a comparative example of the present invention. In the electric 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. Will be done.

One end of the primary coil 310 is connected to the DC power supply 330. As a result, a predetermined voltage (for example, 12V) is applied to the primary coil 310.

The other end of the 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 unit 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, the collector (C) terminal and the emitter (E) terminal of the igniter 340 are energized, and the collector (C) terminal and the emitter (E) terminal are connected to each other. Current flows through. As a result, 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, a current flows through the primary coil 310, and electric power (electrical energy) is accumulated.

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 turns ratio with respect to the primary coil 310 is applied to the secondary side. It occurs in the coil 320.

When a high voltage generated in the secondary coil 320 by the ignition signal SA is applied to the spark plug 200 (center electrode 210), a potential difference is generated between the center electrode 210 of the spark plug 200 and the outer electrode 220. do. When the potential difference generated between the center electrode 210 and the outer electrode 220 becomes equal to or higher than the dielectric breakdown voltage Vm of the gas (air-fuel mixture in the cylinder 150), the gas component is dielectrically broken down to the center electrode 210 and the outer electrode 220. A discharge occurs between the two, and the fuel (air-fuel mixture) is ignited (ignited).

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

[Conventional ignition coil discharge control]
Next, the discharge control of the conventional ignition coil will be described. FIG. 7 is a diagram showing an example of a timing chart for explaining the relationship between the control signal input to the ignition coil and the output in the conventional discharge control. The timing chart of FIG. 7 is an example when the spark plug 200 is discharged when the gas has a high flow velocity by using the conventional ignition coil 300C. In FIG. 7, the ignition signal SA output from the ignition control unit 83, the primary current I1 flowing through the primary coil 310 in response to the ignition signal SA, the electrical energy E stored in the ignition coil 300C, and the secondary side The relationship between the secondary current I2 flowing through the coil 320 and the secondary voltage V2 generated in the secondary coil 320 is shown. As shown in FIG. 6, the measurement points of the secondary current I2 and the secondary voltage V2 are between the spark plug 200 and the ignition coil 300C. The measurement point of the primary current I1 is 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. While the primary coil 310 is energized, the electric energy E in the ignition coil 300C rises with time.

After that, when the ignition signal SA becomes LOW, the igniter 340 cuts off the energization of the primary coil 310. As a result, an electromotive force is generated in the secondary coil 320, and the supply of electric energy E from the ignition coil 300C to the spark plug 200 is started. When the insulation between the electrodes of the spark plug 200 is broken, the spark plug 200 starts to be discharged. The discharge of the spark plug 200 accompanied by such dielectric breakdown is called capacitive discharge. After the discharge of the spark plug 200 is started, the electric energy E in the ignition coil 300C decreases with time, and the discharge of the spark plug 200 is maintained. The discharge of the spark plug 200 without such dielectric breakdown is called an induced discharge.

The secondary current I2 greatly increases when the capacity is discharged. The secondary current I2 due to this capacity discharge 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 drops sharply and then drops with time during the subsequent induced discharge. Since the discharge path extends with the flow of 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 changes according to the flow velocity 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 at which discharge cannot be performed, the spark plug 200 repeatedly blows out and re-discharges the discharge path. The range of the secondary current I2 in which the discharge path is repeatedly blown out and re-discharged in this way 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, and the discharge path is blown out by the gas flow, so that the discharge of the spark plug 200 is interrupted. At this time, since the electric energy E in the ignition coil 300C remains even if the discharge path disappears, re-discharge (re-discharge) accompanied by capacity discharge occurs in the spark plug 200. In the example of FIG. 7, the initial discharge is once and the re-discharge is three times, and the capacity discharge number is four times.

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

In the present invention, instead of the ignition coil 300C described with reference to FIG. 6, an ignition coil 300 having two primary side coils is adopted, and discharge control is performed on the ignition coil 300 to suppress the number of capacitance discharges. The discharge of the spark plug 200 is realized.

[First Embodiment: Electric circuit of ignition coil]
Next, the electric circuit 400 including the ignition coil 300 according to the first embodiment of the present invention will be described.

FIG. 8 is a diagram illustrating an electric circuit 400 including an ignition coil 300 according to the first embodiment of the present invention. In the electric circuit 400, the ignition coil 300 has two types of primary coil 310 and 360 wound with a predetermined number of turns and a secondary side wound with a number of turns larger than the primary coil 310 and 360. It is configured to include and include a coil 320. Here, at the time of ignition of the spark plug 200, the electric power from the primary coil 310 is first supplied to the secondary coil 320, and the electric power from the primary coil 360 is superimposed on the electric power to the secondary coil 320. Is supplied to. Therefore, in the following, the primary coil 310 will be referred to as a "main primary coil" and the primary coil 360 will be referred to as a "secondary primary coil". Further, the current flowing through the main primary coil 310 is referred to as "main primary current", and the current flowing through the primary sub coil 360 is referred to as "secondary primary current".

One end of the main primary coil 310 is connected to the DC power supply 330. As a result, a predetermined voltage (for example, 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 unit 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, the collector (C) terminal and the emitter (E) terminal of the igniter 340 are energized, and the collector (C) terminal and the emitter (E) terminal are connected to each other. Current flows through. As a result, 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 current flows through the main primary coil 310 to accumulate electric power (electrical energy). Will be done.

When the output of the ignition signal SA from the ignition control unit 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 with respect to the main primary coil 310 is generated. It occurs in the secondary coil 320.

One end of the secondary primary coil 360 is connected to the DC power supply 330 in common with the main primary coil 310. As a result, a predetermined voltage (for example, 12V in the embodiment) is also 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. For the igniter 350, a transistor, a field effect transistor (FET), or the like is used.

The base (B) terminal of the igniter 350 is connected to the phase control unit 380 provided in the ignition control unit 83. The phase control unit 380 outputs an ignition signal SB as a signal for controlling the on / off of the igniter 350. The ignition signal SB output from the phase control unit 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, the collector (C) terminal and the emitter (E) terminal of the igniter 350 are energized according to the voltage change of the ignition signal SB, and the collector (C). A current corresponding to the voltage change of the ignition signal SB flows between the terminal) and the emitter (E) terminal. As a result, the ignition signal SB is output from the ignition control unit 83 to the sub-primary coil 360 of the ignition coil 300 via the igniter 350, and the sub-primary current flows through the sub-primary coil 360 to generate electric power (electrical energy). do.

When the output of the ignition signal SB from the phase control unit 380 changes and the secondary primary current flowing through the secondary primary coil 360 changes, a high voltage corresponding to the coil turns ratio to the secondary primary coil 360 becomes secondary. It occurs in the side coil 320.

The high voltage generated in the secondary coil 320 by the ignition signal SA is applied to the high voltage generated in the secondary coil 320 by the ignition signal SB and applied to the spark plug 200 (center electrode 210) to ignite. A potential difference is generated between the center electrode 210 of the plug 200 and the outer electrode 220. When the potential difference generated between the center electrode 210 and the outer electrode 220 becomes equal to or higher than the dielectric breakdown voltage Vm of the gas (air-fuel mixture in the cylinder 150), the gas component is dielectrically broken down to the center electrode 210 and the outer electrode 220. A discharge occurs between the two, and the fuel (air-fuel mixture) is ignited (ignited).

The phase control unit 380 starts the ignition signal SB at a time A when a predetermined superimposition energization start time elapses from the falling time S of the ignition signal SA, and then elapses a predetermined superimposition energization period. The output of the ignition signal SB is controlled so that the ignition signal SB is turned off at the time B. As a result, the electric power from the secondary primary coil 360 is supplied to the spark plug 200 by superimposing on the electric power supplied from the main primary coil 310, and the discharge path formed between the center electrode 210 and the outer electrode 220 is formed. Be maintained. The 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 by using the ignition signals SA and SB by the operation of the electric circuit 400 as described above. As a result, ignition control for controlling the spark plug 200 is performed.

The phase control unit 380 does not have to be provided inside the ignition control unit 83. That is, the ignition control unit 83 and the phase control unit 380 may be configured separately. In any case, since the phase control unit 380 operates according to 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.

[First Embodiment: Discharge control of ignition coil]
Next, the discharge control of the ignition coil according to the first embodiment 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 the predetermined superimposition energization start time and superimposition energization period. The superimposed energization start time is the time from the falling time S of the ignition signal SA to the rising time A of the ignition signal SB, that is, the secondary primary after the discharge of the main primary coil 310 is started according to the ignition signal SA. This is the time until the coil 360 starts to be energized. On the other hand, the superimposed energization period is the time from the rise time A to the fall time B of the ignition signal SB, that is, the time from the start to the end of energization of the secondary primary coil 360. These times are set based on the result of measuring the occurrence state of re-discharge when the spark plug 200 is discharged in the cylinder 150 in the development stage of the ignition control unit 83. Hereinafter, an example of the specific method will be described.

First, in the electric circuit 400 shown in FIG. 8, a voltage sensor is installed between the spark plug 200 and the ignition coil 300, and the voltage sensor is used to discharge the spark plug 200 in the cylinder 150. The voltage V2 is detected. In addition, instead of the electric circuit 400, the electric circuit 400C shown in FIG. 6 may be used to detect the secondary voltage V2 when the spark plug 200 is discharged in the cylinder 150. Then, based on the obtained value of the secondary voltage V2, the secondary voltage V2 (hereinafter referred to as “re-discharge voltage”) at the time immediately before the re-discharge of the ignition plug 200 occurs is measured and re-discharged. Based on the time when the voltage is measured, the time from the start of discharge to the re-discharge of the ignition plug 200 (hereinafter referred to as "re-discharge time") is measured.

For example, in the waveform of the secondary voltage V2 shown in FIG. 7, the maximum value of the secondary voltage V2 during the discharge period of the spark plug 200, that is, the value immediately before the secondary voltage V2 suddenly drops after the start of discharge is V2max. Is defined as. The re-discharge voltage and the re-discharge time are measured by obtaining the value of V2max and the time from the fall of the ignition signal SA to the detection of V2max (V2max timing) from the detection results of the secondary voltage V2, respectively. It can be performed. When 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. By doing so, the point where the secondary voltage V2 drops sharply can be easily detected as V2max, and the re-discharge time can be measured.

By measuring the re-discharge voltage and re-discharge time multiple times based on the detection result of the secondary voltage V2 as described above and statistically processing each measurement result, the set values of the superimposition energization start time and superimposition energization period are performed. Is determined. The method will be described below with reference to FIGS. 9 and 10.

FIG. 9 is a diagram showing an example of a scatter diagram in which the measurement results of the re-discharge voltage and the re-discharge time are recorded. In this scatter plot, the horizontal axis represents the V2max time starting from the fall time S of the ignition signal SA, that is, the re-discharge time, and the vertical axis represents the value of V2max, that is, the re-discharge voltage.

During the operation of the internal combustion engine 100, the gas flow between the electrodes of the spark plug 200 and the temperature of the electrodes in the cylinder 150 vary from combustion cycle to combustion cycle. Therefore, as shown in FIG. 9, the values of V2max and V2max timing fluctuate with each combustion cycle and are not constant. However, when trying to supply the superimposed current to the spark plug 200 by the secondary primary coil 360 within the range of all the re-discharge times according to the fluctuation range of the Vmax timing, the energization time of the secondary primary coil 360 is excessive. Will be. As a result, the power consumption and heat generation amount of the ignition coil 300 become excessive, and in order to mount the ignition coil 300, the cooling capacity of the ignition coil 300 must be increased more than necessary, which causes an increase in volume and cost. There is a risk.

Therefore, in the present embodiment, in the distribution of each measurement result when the re-discharge time is measured a plurality of times, the energization period of the sub-primary coil 360 that is permissible for heat generation is set as the superimposition energization period, and within this superimposition energization period. The superimposition energization start time is set so that the number of times of re-discharge of the spark plug 200 is maximized. As a result, the occurrence of re-discharge in the spark plug 200 is suppressed as much as possible without increasing the cooling capacity of the ignition coil 300, the power consumption of the ignition coil 300 is suppressed, and the discharge path between the electrodes of the spark plug 200 is extended. , I try to make it compatible.

Specifically, for example, in the scatter diagram shown in FIG. 9, the line segments 91 and 92 corresponding to the rise time A and the fall time B of the ignition signal SB are set, respectively, and the interval between the line segments 91 and the line segment 92 is set. It is fixed according to the energization period of the sub-primary coil 360, which is permissible in terms of heat generation according to the rotation speed of the internal combustion engine 100. In this state, the line segments 91 and 92 are moved laterally on the scatter plot to search for the position where the number of measurement points between the line segment 91 and the line segment 92 is maximized. The superimposition energization start time can be set according to the position of the line segment 91 searched in this way. If there is no problem in heat generation of the ignition coil 300, the superimposition energization start time may be set so that all the measurement points are inserted between the line segment 91 and the line segment 92.

Further, in the scatter diagram shown in FIG. 9, the line segments 93 and 94 corresponding to the lower limit voltage C and the upper limit voltage D of the secondary voltage V2 may be set, respectively. For example, based on the distance between the line segment 93 and the line segment 94, the number of measurement points between the line segment 93 and the line segment 94, and the like, the positions of the line segment 93 and the line segment 94 are set so as to satisfy a predetermined condition. Decide each. At this time, all the measurement points may be inserted 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 can be set according to the positions of the line segments 93 and 94 set in this way, and the ignition signal SB can be controlled using these. The method of controlling the ignition signal SB using the lower limit voltage C and the upper limit voltage D will be described in the second embodiment described later.

The measurement result of the re-discharge time may be recorded in a histogram, and the superimposed energization start time may be set using this 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 this histogram, the horizontal axis represents the V2max time starting from the fall time S of the ignition signal SA, that is, the re-discharge time, and the vertical axis represents the number of combustion cycles of the internal combustion engine 100 in which the value of each V2max time is measured, that is. It shows the frequency of each measurement result of the re-discharge time.

Also in the histogram shown in FIG. 10, the superimposed energization start time can be set by the same method as the scatter diagram of FIG. That is, the line segments 95 and 96 corresponding to the rise time A and the fall time B of the ignition signal SB are set, respectively, and the interval between the line segments 95 and the line segment 96 is allowed to generate heat according to the rotation speed of the internal combustion engine 100. It is fixed according to the energization period of the sub-primary coil 360 that can be formed. In this state, the line segments 95 and 96 are moved laterally on the histogram to search for the position where the total value (frequency) of the number of combustion cycles between the line segments 95 and 96 is maximized. The superimposition energization start time can be set according to the position of the line segment 95 searched in this way. If there is no problem in heat generation of the ignition coil 300, the entire region where the histogram is distributed may be set as the superimposed energization start time.

In the above, the method of setting the superimposed energization start time when the measurement result of the re-discharge time is recorded using the scatter diagram of FIG. 9 and the histogram of FIG. 10 has been described, but the measurement result of the re-discharge time can be obtained by another method. Even in the case of recording, the superimposed energization start time can be set in the same manner as in FIGS. 9 and 10. That is, in the distribution of the measurement results of the re-discharge time recorded by an arbitrary method, it is preferable to set the superposition energization start time so that the number of times of re-discharge occurs is maximized within a predetermined superposition energization period.

FIG. 11 is a diagram showing an example of a timing chart for explaining the relationship between the control signal input to the ignition coil and the output in the discharge control according to the first embodiment of the present invention. The timing chart of FIG. 11 is an example when the spark plug 200 is discharged when the gas has a high flow velocity by using the ignition coil 300 of the present embodiment. In FIG. 11, an ignition signal SA output from the ignition control unit 83, a main primary current I1 flowing through the main primary coil 310 in response to the ignition signal SA, and an ignition signal SB output from the phase control unit 380. , The secondary primary current I3 flowing in the secondary primary coil 360 according to the ignition signal SB, the electric energy E stored in the ignition coil 300, the secondary current I2 flowing in the secondary coil 320, and the secondary coil. The relationship with the secondary voltage V2 generated in 320 is shown.

When the ignition signal SA becomes HIGH, the igniter 340 energizes the main primary coil 310, and the main primary current I1 rises. While the main primary coil 310 is energized, the electric energy E in the ignition coil 300 rises with time.

After that, when the ignition signal SA becomes LOW at the falling time S, the igniter 340 cuts off the energization of the main primary coil 310. As a result, an electromotive force is generated in the secondary coil 320, and the supply of electric energy E from the ignition coil 300 to the spark plug 200 is started. When the insulation between the electrodes of the spark plug 200 is broken, discharge (capacitive discharge) of the spark plug 200 is started. After the discharge of the spark plug 200 is started, the electric energy E in the ignition coil 300 decreases with time, and the discharge (induced discharge) of the spark plug 200 is maintained.

The secondary current I2 and the secondary voltage V2 greatly increase when the capacity is discharged. The increase in the secondary current I2 and the secondary voltage V2 due to this capacitance discharge 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 and the secondary voltage V2 each drop sharply. During the subsequent induced discharge, the secondary current I2 decreases with time. On the other hand, since the discharge path extends with the flow of 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 changes according to the flow velocity of the gas existing between the electrodes of the spark plug 200.

The phase control unit 380 turns on the ignition signal SB at the time A when a predetermined superimposed energization start time elapses from the falling time S when the ignition signal SA changes from HIGH to LOW. After that, the ignition signal SB is turned off at the time B when the predetermined superimposed energization period has elapsed from the time A. The superimposition energization start time and superimposition energization period used in the control of the ignition signal SB are preset in the phase control unit 380 as described above. That is, the superimposed energization start time is set based on the result of statistical processing of the measurement result of the re-discharge time when the spark plug 200 is discharged in the cylinder 150. Further, the superimposed energization period is set in advance according to the energization period of the sub-primary coil 360 that can be tolerated in terms of heat generation according to the rotation speed of the internal combustion engine 100.

While the phase control unit 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 added to the high voltage generated in the secondary side coil 320 by the ignition signal SA. .. This high voltage is applied to the spark plug 200 (center electrode 210). As a result, the secondary current I2 is increased and the maintenance of the discharge path is continued. Therefore, in the spark plug 200, the occurrence of re-discharge (re-discharge) accompanied by capacitance discharge is suppressed. In the example of FIG. 11, the initial discharge is once and the re-discharge is once, and the capacity discharge number is twice.

The secondary current I2 when the ignition signal SB is output includes a current flowing through the secondary coil 320 by the main primary coil 310 and a current flowing through the secondary coil 320 by the secondary primary coil 360. Is included.

FIG. 12 is a diagram illustrating the effect of the present invention. In FIG. 12, the signal waveform 501 shows the waveform of the ignition signal SB output by the method described in the above embodiment as the ignition signal for the superimposed current according to the present invention. The pulse width of the ignition signal SB in the signal waveform 501, that is, the superimposed energization period from the rising time A when the ignition signal SB is turned on to the falling time B when the ignition signal SB is turned off is determined according to the rotation speed of the internal combustion engine 100. For example, when the rotation speed of the internal combustion engine 100 is 2400 [rpm], it is 0.5 [msec]. On the other hand, the signal waveform 502 shows the waveform of the ignition signal SB output for the entire range of the re-discharge time that can occur in the spark plug 200 as the ignition signal for the superimposed current according to the comparative example. Further, the current waveforms 503 and 504 show examples of waveforms of the secondary current I2 flowing according to the ignition signal SB shown in these signal waveforms 501 and 502, respectively.

Plot FIG. 505 shows the relationship between the energy consumption of the ignition coil 300 and the combustion stability of the spark plug 200 due to the supply of the superimposed current according to the ignition signal SB. In this plot diagram 505, points 506 and 507 represent the relationship between the energy consumption by 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. Further, the point 508 represents the relationship between the energy consumption and the connection stability in the conventional example using the electric circuit 400C of FIG.

Comparing points 506 and 507, the comparative example is equivalent to the present invention in terms of combustion stability (ignition performance), but the present invention is significantly reduced in energy consumption (calorific value) as compared to the comparative example. You can see that there is. Further, when points 506 and 508 are compared, it can be seen that although the energy consumption (calorific value) is slightly increased in the present invention as compared with the conventional example, the combustion stability (ignition performance) is greatly improved.

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

[First embodiment: Flow of setting the superimposition energization start time]
Next, in order to carry out the above discharge control, a method of setting the superimposition energization start time performed in advance will be described. FIG. 13 is an example of a flowchart illustrating a method of setting a superimposed energization start time according to the first embodiment of the present invention. In the process shown in the flowchart of FIG. 13, for example, in the development stage of the ignition coil 300 or before shipment, the ignition coil 300 attached to the internal combustion engine 100 is connected to the ignition control unit 83 via the igniters 340 and 350 to ignite. Before the actual operation of the coil 300 is started, it is carried out in a predetermined experimental facility or test facility.

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

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

In step S103, the time derivative 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 the spark plug 200 is blown out and 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 the detection of 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 re-discharge occurs based on the time derivative dV2 / dt of the secondary voltage V2 by the process of step S103. I try to do it. As a result, compared to the case where the occurrence of re-discharge is detected based on the primary voltage V1, the presence or absence of re-discharge can be directly determined from the voltage between the electrodes of the spark plug 200, so that the detection accuracy can be improved. can. It is also possible to detect the occurrence of re-discharge based on the secondary current I2, but as shown in FIG. 7, the change in the secondary current I2 due to the re-discharge of the spark plug 200 is instantaneous in a short time. It happens in. 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 becomes possible.

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 excess time is recorded in step S104, and the maximum point is detected from the value. Thereby, the timing immediately before the re-discharge between the electrodes of the spark plug 200 can be detected.

In step S105, the time of occurrence of the maximum point detected in step S104 is recorded as the maximum time.

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

In step S107, a distribution map of the maximum period recorded in step S105 carried out so far is created. Here, for example, a scatter plot as shown in FIG. 9 and a histogram as shown in FIG. 10 can be created as a distribution map at the maximum time.

In step S108, the interval between the rise time A and the fall time B of the ignition signal SB is set with respect to the distribution map created in step S107. Here, as described above, the interval between the rise time A and the fall time B on the distribution map is fixed according to the energization period of the sub-primary coil 360 that can tolerate heat generation according to the rotation speed of the internal combustion engine 100. ..

In step S109, in the distribution map created in step S107, the rise time A and the fall time B in which the total number of times the maximum time is recorded is maximized within the range of the fixed interval set in step S108 are specified. ..

In step S110, the superimposed energization start time is set based on the rise time A and the fall time B specified in step S109.

When the superimposition energization start time can be set by the above processing, the processing flow of FIG. 13 is terminated in step S111.

It is preferable that the process of FIG. 13 is performed 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 process of FIG. 13 is performed for each measurement target value. By doing so, it is possible to set the superimposed energization start time for each operating state of the internal combustion engine 100.

[First Embodiment: Discharge control flow of the secondary primary coil]
Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 when the above discharge control is performed will be described. FIG. 14 is an example of a flowchart illustrating a method of controlling the sub-primary coil 360 by the phase control unit 380 according to the first embodiment of the present invention. In the present embodiment, when the ignition switch of the vehicle is turned on and the power of the internal combustion engine 100 is turned on, the phase control unit 380 starts controlling the sub-primary coil 360 according to the flowchart of FIG. The process shown in the flowchart of FIG. 14 represents the process for one cycle of the internal combustion engine 100, and the phase control unit 380 performs the process shown in the flowchart of FIG. 14 for each cycle.

In step S201, the phase control unit 380 starts the process shown in the flowchart of FIG.

In step S202, the phase control unit 380 selects the superimposed energization start time. Here, the superimposition energization start time according to the operating state of the internal combustion engine 100, for example, the engine rotation speed is selected by using the preset map information or the like. The map information used here represents the superimposed energization start time for each operating state of the internal combustion engine 100, and is set in advance by the process of FIG.

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 the output of the ignition signal SA at a predetermined timing, and then stops the output of the ignition signal SA at a predetermined timing. As a result, the main primary coil 310 starts supplying the electric energy E to the spark plug 200, and the spark plug 200 is started to be discharged. The phase control unit 380 can detect the discharge start time of the spark plug 200 by detecting the falling time S of the ignition signal SA at this time in step S203.

In step S210, the phase control unit 380 measures the elapsed time from that point to the present, 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 superimposed energization start time selected in step S202 with the elapsed time measured in step S210, and has the superimposed energization start time elapsed from the falling time S of the ignition signal SA? Judge whether or not. If the elapsed time is less than the superimposed energization start time, it is determined that the superimposed energization start time has not yet 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. As a result, the supply of the superimposed current from the secondary primary coil 360 to the spark plug 200 is started at the rise time A of the ignition signal SB.

In step S221, the phase control unit 380 compares the elapsed time from that point to the present with the predetermined superimposed energization period, starting from the rise time A of the ignition signal SB determined by performing the process of step S220. As described above, the superimposed energization period compared here is preset according to the energization period of the sub-primary coil 360 that can be tolerated in terms of heat generation according to the rotation speed of the internal combustion engine 100. As a result, if the elapsed time is less than the superimposed energization period, it is determined that the superimposed energization period has not yet 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 energization period, it is determined that the superimposed energization 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 the output of the ignition signal SB. As a result, the supply of the superimposed current from the secondary primary coil 360 to the spark plug 200 is stopped at the falling time B of the ignition signal SB.

In step S223, the phase control unit 380 ends the process shown in the flowchart of FIG.

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

(1) The control device 1 which is an electronic control device is an ignition provided with a main primary coil 310 and a secondary primary coil 360 arranged on the primary side, respectively, and a secondary coil 320 arranged on the secondary side. By controlling the energization of the coil 300, the supply of electric energy from the ignition coil 300 to the spark plug 200 discharged in the cylinder 150 of the internal combustion engine 100 is controlled. The control device 1 energizes the sub-primary coil 360 when a predetermined superposition energization start time elapses (step S211: Yes) after the phase control unit 380 starts discharging the main primary coil 310. When a predetermined superposition energization period corresponding to the rotation speed of the internal combustion engine 100 has elapsed since the start (step S220) and the energization of the sub-primary coil 360 are started (step S221: Yes), the sub-primary coil 360 is started. The energization of the ignition coil 300 is controlled so as to end the energization of (step S222). Since this is done, it is possible to achieve both improvement in fuel efficiency of the internal combustion engine 100 and suppression of ignition failure of the fuel by the spark plug 200, while suppressing an increase in the volume and cost of the ignition coil 300.

(2) The superimposed 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 spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100. Specifically, the superimposed energization start time is the maximum number of times of re-discharge occurs within a predetermined superimposed energization period in the distribution of each measurement result when the re-discharge time is measured a plurality of times by the process of FIG. Is determined to be (steps S109, S110). Since this is done, it is possible to appropriately determine the energization start timing of the sub-primary coil 360 so that the improvement of the fuel efficiency of the internal combustion engine 100 and the suppression of the ignition failure of the fuel by the spark plug 200 can be achieved at the same time.

(3) In the measurement of the re-discharge time, the occurrence of re-discharge is 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. May be good. By doing so, it is possible to determine that re-discharge has occurred when the secondary voltage V2 drops sharply, and to easily detect the occurrence of re-discharge. Therefore, the re-discharge time can be accurately measured.

[Second embodiment: electric circuit of ignition coil]
Next, the electric circuit 400A including the ignition coil 300 according to the second embodiment of the present invention will be described.

FIG. 15 is a diagram illustrating an electric circuit 400A including an ignition coil 300 according to a second embodiment of the present invention. In the present embodiment, the ignition coil 300 has the same configuration as that of FIG. 8 described in the first embodiment. That is, the ignition coil 300 of the present embodiment also has two types of primary coil 310 and 360 (main primary coil 310 and secondary primary coil 360) wound by a predetermined number of turns, and a primary coil 310. It is configured to include a secondary coil 320 wound with a number of turns larger than 360.

In the present embodiment, the electric circuit 400A is different from the electric circuit 400 described in the first embodiment in that the voltage detection unit 370 is provided between the secondary coil 320 and the spark plug 200. There is. The voltage detection unit 370 detects the secondary voltage V2 and transmits the value to the ignition control unit 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 superimposed energization voltage range. This superimposed energization voltage range reappears when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100 in the development stage of the ignition control unit 83, similarly to the superimposed energization start time described in the first embodiment. It is set based on the result of measuring the discharge occurrence status. Specifically, for example, in the scatter diagram of FIG. 9 described in the first embodiment, the lower limit voltage C and the upper limit voltage D of the secondary voltage V2 are set as described above, and the lower limit voltage C and the upper limit voltage D are set. The voltage range between is set as the superimposed energization voltage range.

In addition, even when the occurrence status of re-discharge is recorded by another method, the superimposed energization voltage range can be set in the same manner. In the distribution of the re-discharge voltage recorded by an arbitrary method, that is, the measurement result of the secondary voltage V2 immediately before the occurrence of the re-discharge, superimposition is performed so that the number of times of the re-discharge occurs is the maximum within the predetermined voltage range. It is possible to set the lower limit voltage and the upper limit voltage of the energizing voltage range.

As a result of comparing the secondary voltage V2 and the superposed energizing voltage range, when the spark plug 200 is re-discharged when the secondary voltage V2 is within the superposed energizing voltage range, the phase control unit 380 performs the first operation. The ignition signal SB is output in the same manner as described in the embodiment. As a result, the superimposed current is supplied from the sub-primary coil 360 to the spark plug 200, and the occurrence of re-discharge (re-discharge) accompanied by capacitance discharge is suppressed in the spark plug 200. On the other hand, when the spark plug 200 is re-discharged when the secondary voltage V2 is out of the superimposed energization voltage range, the phase control unit 380 prevents the ignition signal SB from being output. As a result, when the possibility of re-discharging in the spark plug 200 is low, the supply of the superimposed current from the secondary primary coil 360 to the spark plug 200 is stopped so that the power consumption is suppressed.

[Second embodiment: Flow of setting superimposition energization start time and superimposition energization voltage range]
Next, in order to carry out the above discharge control, a method of setting the superimposition energization start time and the superimposition energization voltage range performed in advance will be described. FIG. 16 is an example of a flowchart illustrating a method of setting a superposed energization start time and a superposed energization voltage range according to a second embodiment of the present invention. In the flowchart of FIG. 16, each step for carrying out the same process as the flowchart of FIG. 13 described in the first embodiment is assigned the same step number as that of FIG. Hereinafter, the processing shown in the flowchart of FIG. 16 will be described with a focus on the differences from FIG.

In step S105A, the value of the maximum point detected in step S104 and the time of occurrence are recorded as the maximum value and the maximum time, respectively.

In step S107A, a distribution map of the maximum value and the maximum time recorded in step S105A carried out so far is created. Here, for example, a scatter plot as shown in FIG. 9 can be created as a distribution map of a maximum value and a maximum time.

In step S108A, the interval between the rise time A and the fall time B of the ignition signal SB and the interval between the lower limit voltage C and the upper limit voltage D are set with respect to the distribution map created in step S107A. Here, as described above, the interval between the rise time A and the fall time B on the distribution map is fixed according to the energization period of the secondary primary coil 360 that can tolerate heat generation, and a predetermined condition, for example, power consumption, is fixed. The interval between the lower limit voltage C and the upper limit voltage D is fixed based on the required value of.

In step S109A, in the distribution map created in step S107A, the rise time A, the fall time B, and the lower limit in which the total number of times the maximum time is recorded is the maximum within the range of the fixed interval set in step S108A. The voltage C and the upper limit voltage D are specified respectively.

In step S110A, the superimposed energization start time is set based on the rise time A and the fall time B specified in step S109A. Further, the superimposed energization voltage range is set based on the lower limit voltage C and the upper limit voltage D specified in step S109A.

When the superimposition energization start time and the superimposition energization voltage range can be set by the above processing, the processing flow of FIG. 16 is terminated in step S111.

It is preferable that the process of FIG. 16 is also performed for each operating state of the internal combustion engine 100, similarly to the process of FIG. 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. By doing so, the superimposition energization start time and the superimposition energization voltage range can be set for each operating state of the internal combustion engine 100.

[Second embodiment: Discharge control flow of the secondary primary coil]
Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 when the above discharge control is performed will be described. FIG. 17 is an example of a flowchart illustrating a method of controlling the sub-primary coil 360 by the phase control unit 380 according to the second embodiment of the present invention. In the flowchart of FIG. 17, each step for carrying out the same process as the flowchart of FIG. 14 described in the first embodiment is assigned the same step number as that of FIG. Hereinafter, the processing shown in the flowchart of FIG. 17 will be described with a focus on the differences from FIG.

If the elapsed time from the fall time S of the ignition signal SA in step S211 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 S212.

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

In step S213, the phase control unit 380 compares the secondary voltage V2 acquired in step S212 with the preset superimposed energization voltage range, and determines whether or not the secondary voltage V2 is within the superimposed energization voltage range. judge. The superimposed energization voltage range used for comparison with the secondary voltage V2 here is set in advance by the process of FIG. 16, and is set for each operating state of the internal combustion engine 100.

When it is determined in step S213 that the secondary voltage V2 is within the superimposed energization voltage range, the phase control unit 380 proceeds to step S220, turns on the ignition signal SB, and starts outputting the ignition signal SB. As a result, the supply of the superimposed current from the secondary primary coil 360 to the spark plug 200 is started at the rise time A of the ignition signal SB. On the other hand, if it is determined in step S213 that the secondary voltage V2 is out of the superimposed energization voltage range, that is, if it is larger than the upper limit voltage D or less than the lower limit voltage C, the phase control unit 380 proceeds to step S223. , The process shown in the flowchart of FIG. 17 is terminated. In this case, the superimposed current is not supplied from the secondary primary coil 360 to the spark plug 200.

According to the second embodiment of the present invention described above, in addition to the (1) to (3) described in the first embodiment, the following effects are further exerted.

(4) In the control device 1, the voltage V2 of the secondary coil 320 when the superimposed energization start time elapses after the discharge of the main primary coil 310 is started by the phase control unit 380 is higher than the predetermined upper limit voltage D. When it is large or less than the predetermined lower limit voltage C (step S213: No), the sub-primary coil 360 is not energized. Therefore, when the possibility of re-discharging in the spark plug 200 is low, the supply of the superimposed current from the secondary primary coil 360 to the spark plug 200 is stopped to further reduce the power consumption of the spark plug 300. It can be suppressed.

(5) The upper limit voltage D and the lower limit voltage C are the re-discharge voltages indicating the voltage V2 of the secondary coil 320 immediately before the occurrence of re-discharge when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100. Determined based on the measurement results. Specifically, the upper limit voltage D and the lower limit voltage C are the number of occurrences of re-discharge within a predetermined voltage range in the distribution of each measurement result when the re-discharge voltage is measured a plurality of times by the process of FIG. Is determined to be the maximum (steps S109A, S110A). Since this is done, the secondary voltage for energizing the secondary primary coil 360 so that the ignition failure of the gas by the spark plug 200 can be suppressed and the power consumption of the ignition coil 300 can be further suppressed. The range of V2 can be set appropriately.

[Third Embodiment: electric circuit of ignition coil]
Next, the electric circuit 400B including the ignition coil 300 according to the third embodiment of the present invention will be described.

FIG. 18 is a diagram illustrating an electric circuit 400B including an ignition coil 300 according to a third embodiment of the present invention. In the present embodiment, the ignition coil 300 has the same configuration as that of FIG. 8 described in the first embodiment. That is, the ignition coil 300 of the present embodiment also has two types of primary coil 310 and 360 (main primary coil 310 and secondary primary coil 360) wound by a predetermined number of turns, and a primary coil 310. It is configured to include a secondary coil 320 wound with a number of turns larger than 360.

In the present embodiment, the electric circuit 400B has a timer circuit 381 installed separately from the ignition control unit 83 as compared with the electric circuit 400 described in the first embodiment, and the phase control unit 380 is provided in the timer circuit 381. The point that it is provided is different. The timer circuit 381 sets a timer value according to the superimposed energization period, and when the ignition signal SB is output by the phase control unit 380 and the energization of the sub-primary coil 360 is started, the ignition signal SB rises from the rise time A. Count the elapsed time of. Then, when the elapsed time reaches the set timer value, the output of the ignition signal SB is stopped and the energization of the secondary primary coil 360 is terminated. In the present embodiment, the ON period of the ignition signal SB is controlled by using the function of the timer circuit 381.

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

FIG. 19 is an example of map information showing the 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 the 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 shorter the ON period of the ignition signal SA, the shorter the ON period of the ignition signal SB is set.

The timer circuit 381 utilizes the relationship between the engine speed and the ON period of the ignition signal SA shown in FIG. 19, for example, according to the graph of FIG. 20, of the ignition signal SB corresponding to the ON period of the acquired ignition signal SA. Set the timer value according to the ON period. This makes it possible to set a timer value that changes according to the engine speed without using map information preset for each operating state of the internal combustion engine 100.

In the above, the ignition signal SB is set by setting the timer value of the timer circuit 381 based on the ON period of the ignition signal SA by utilizing the fact that the ON period of the ignition signal SA changes according to the engine rotation speed of the internal combustion engine 100. Although an example of controlling the ON period of the ignition signal SA has been described, the same control is possible for the cycle of the ignition signal SA, that is, the discharge cycle of the spark plug 200. That is, the cycle of the ignition signal SA changes according to the engine speed of the internal combustion engine 100. Therefore, by utilizing this, the timer value of the timer circuit 381 can be set based on the cycle of the ignition signal SA to control the ON period of the ignition signal SB. Even in this way, it is possible to set the timer value that changes according to the engine speed without using the map information set in advance for each operating state of the internal combustion engine 100.

[Third Embodiment: Discharge control flow of the secondary primary coil]
Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 and the timer circuit 381 when the above discharge control is performed 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 the third embodiment of the present invention. In the flowchart of FIG. 21, each step for carrying out the same process as the flowchart of FIG. 14 described in the first embodiment is assigned the same step number as that of FIG. Hereinafter, the processing shown in the flowchart of FIG. 21 will be described with a focus on the differences from FIG.

When the process shown in the flowchart of FIG. 21 is started in step S201, the phase control unit 380 selects the superimposed energization start time in step S202. Here, using the information set in advance by the same method as in the first embodiment, the superimposition energization start time according to the operating state of the internal combustion engine 100, for example, the engine rotation speed is selected.

When it is determined in step S203 that the ignition signal SA has changed from HIGH to LOW, the timer circuit 381 acquires the ON period of the ignition signal SA in the following 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 the timer value based on the ON period of the ignition signal SA acquired 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.

When setting the timer value of the timer circuit 381 based on the cycle of the ignition signal SA as described above, in step S204, the cycle is acquired instead of the ON period of the ignition signal SA, and the step is based on the cycle. The timer value may be set by executing the process of S205.

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 since the ignition signal SB was turned on in step S220 with the timer value set in step S205. As a result, if the elapsed time is less than the timer value, it is determined that the superimposed energization period has not yet elapsed, and the determination in step S221 is continued. On the other hand, when the elapsed time reaches the timer value, it is determined that the superimposed energization period has elapsed, and the process proceeds to step S222.

According to the third embodiment of the present invention described above, in addition to the (1) to (3) described in the first embodiment, the following effects are further exerted.

(6) The control device 1 sets a timer value according to the superimposed energization period, and when the elapsed time from the start of energization of the sub-primary coil 360 reaches the timer value, the sub-primary coil 360 is energized. It has a timer circuit 381 that ends. Since this is done, it is possible to control the energization of the sub-primary coil 360 that reflects the operating state of the internal combustion engine 100 without using the map information preset for each operating state of the internal combustion engine 100.

(7) The timer circuit 381 sets the timer value based on the charge period of the main primary coil 310 or the discharge cycle of the spark plug 200. Since this is done, the timer value can be set so as to appropriately change the energization period of the sub-primary coil 360 according to the engine speed.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In this embodiment, an example of correcting the superimposition energization start time according to the gas flow velocity between the electrodes during the discharge of the spark plug 200 will be described using the electric circuit 400A described in the second embodiment.

FIG. 22 is a diagram showing an example of a timing chart for explaining the relationship between the control signal input to the ignition coil and the output in the discharge control according to the fourth embodiment 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 timings T1 and T2 are acquired during the discharge period of the spark plug 200 after the falling time S of the ignition signal SA, respectively. .. Then, the slope of the graph showing the time change of the secondary voltage V2 is obtained from the acquired value of each secondary voltage V2, and the superimposed energization start time is adjusted based on the magnitude of the slope. For example, the superimposition energization start time can be adjusted by using a preset superimposition energization start time as a reference value and adding a correction value according to a time change of the secondary voltage V2 to the reference value.

The secondary voltage V2 during discharge of the spark plug 200 changes according to the gas flow velocity between the electrodes. Therefore, by obtaining the slope of the graph showing the time change of the secondary voltage V2 as described above and changing the superimposed energization start time according to the magnitude of the slope, the ignition signal starts from the falling time S of the ignition signal SA. The time interval until the rise time A of the SB can be adjusted according to the gas flow velocity between the electrodes. Therefore, it is possible to correct the superimposition energization start time according to the gas flow velocity between the electrodes during the discharge of the spark plug 200.

FIG. 23 is an example of a graph showing the relationship between the gas flow velocity between the electrodes (time change of the secondary voltage V2) and the correction addition value with respect to the rise time A of the ignition signal SB. As shown in the graph of FIG. 23, the higher the gas flow velocity between the electrodes and the larger the time change of the secondary voltage V2, the smaller the correction addition value for the rise time A is set, whereby the ignition signal SB is set. The rise time A of is corrected to be ahead of schedule. As a result, the superimposition energization start time can be shortened, and the energization period of the secondary primary coil 360 can be adjusted according to the gas flow velocity.

[Fourth Embodiment: Discharge control flow of the secondary primary coil]
Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 when the above discharge control is performed will be described. FIG. 24 is an example of a flowchart illustrating a method of controlling the sub-primary coil 360 by the phase control unit 380 according to the fourth embodiment of the present invention. In the flowchart of FIG. 24, each step for carrying out the same process as the flowchart of FIG. 14 described in the first embodiment is assigned the same step number as that of FIG. Hereinafter, the processing shown in the flowchart of FIG. 24 will be described with a focus on the differences from FIG.

When the process shown in the flowchart of FIG. 24 is started in step S201, the phase control unit 380 selects the superimposed energization start time in step S202. Here, using the information set in advance by the same method as in the first embodiment, the superimposition energization start time according to the operating state of the internal combustion engine 100, for example, the engine rotation speed is selected.

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

In step S207, the phase control unit 380 estimates the gas flow velocity 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 time immediately before that, and the gas flow velocity between the electrodes is estimated from the magnitude of the slope. do. If only one value of the secondary voltage V2 has been acquired and 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 superimposed energization start time selected in step S202 based on the gas flow velocity estimated in step S207. Here, for example, the correction addition value is determined based on the relationship between the gas flow velocity between the electrodes shown in FIG. 23 and the correction addition value for the rise time A of the ignition signal SB, and the correction addition value is added to superimpose energization. Correct the start time. As a result, the superimposed energization start time is changed based on the time change of the secondary voltage V2 according to the change of the gas flow velocity.

The superimposed 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, and superimposes energization from the falling time S of the ignition signal SA. Determine if the start time has passed. As a result, if the elapsed time is less than the superimposed energization start time, it is determined that the superimposed energization start time has not yet elapsed, and the process returns to step S206 to correct the superimposed energization start time based on the time change of the secondary voltage V2. , Continue to measure 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.

According to the fourth embodiment of the present invention described above, in addition to the (1) to (3) described in the first embodiment, the following effects are further exerted.

(8) The control device 1 changes the superimposed energization start time based on the time change of the voltage V2 of the secondary coil 320 by the phase control unit 380 (steps 206 to S208). Since this is done, the energization period of the secondary primary coil 360 can be adjusted according to the gas flow velocity between the electrodes in the spark plug 200. Therefore, even when the operating state of the internal combustion engine 100 fluctuates in each combustion cycle, it is possible to reliably suppress ignition failure of the gas by the spark plug 200. This is not only a series hybrid type electric vehicle in which a power generation motor is driven by the internal combustion engine 100 and the drive motor is driven by the electric power, but also a conventional automobile or a parallel hybrid in which the vehicle is driven by the internal combustion engine 100. It is also suitable for type electric vehicles.

[Modification example]
In each of the first to fourth embodiments described above, in the control device 1, the phase control unit 380 determines the discharge start timing of the main primary coil 310, that is, the ignition signal SA, according to the operating state of the internal combustion engine 100. As the falling time S of the ignition signal SA becomes earlier, the period from the falling time S of the ignition signal SA to the rising time A of the ignition signal SB may be lengthened to increase the superimposed energization start time. By doing so, when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100, the ignition signal SB is output in accordance with the timing at which the tumble flow collapse (tumble collapse) occurs in the gas in the cylinder 150. Then, the superimposed current can be supplied from the secondary primary coil 360 to the spark plug 200. Therefore, it is possible to effectively suppress the blowout of the discharge path due to the collapse of the tumble and improve the ignitability of the gas by the spark plug 200.

In each of the above-described embodiments, the functional configurations of the control device 1 described with reference to FIG. 3 may be realized by software executed by the MPU 50 as described above, or may be realized by FPGA (Field-Programmable Gate Array). ) And other hardware may be used. Further, these may be mixed and used.

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

The embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired. Further, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects considered within the scope of the technical idea of the present invention are also included within the scope of the present invention.

1: Control device, 10: Analog input unit, 20: Digital input unit, 30: A / D conversion unit, 40: RAM, 50: MPU, 60: ROM, 70: I / O port, 80: Output circuit, 81 : Overall control unit, 82: Fuel injection control unit, 83: Ignition control unit, 84: Cylinder discrimination unit, 85: Angle information generation unit, 86: Rotation speed information generation unit, 87: Intake amount measurement unit, 88: Load information Generation unit, 89: Water temperature measurement unit, 100: Internal combustion engine, 110: Air cleaner, 111: Intake pipe, 112: Intake manifold, 113: Throttle valve, 113a: Throttle opening sensor, 114: Flow sensor, 115: Intake temperature sensor , 120: Ring gear, 121: Crank angle sensor, 122: Water temperature sensor, 123: Crank shaft, 125: Accelerator pedal, 126: Accelerator 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: Intake valve, 152: Exhaust valve, 160: Exhaust manifold, 161: Three-way catalyst, 162: Upstream air fuel ratio sensor, 163: Downstream air fuel ratio sensor, 170: piston, 200: ignition plug, 210: center electrode, 220: outer electrode, 230: insulator, 300, 300C: ignition coil, 310: main primary coil, 320: secondary side coil , 330: DC power supply, 340, 350: Igniter, 360: Secondary primary coil, 370: Voltage detector, 380: Phase control unit, 381: Timer circuit, 390: Resistance, 400, 400A, 400B, 400C: Electric circuit

Claims (12)

1. By controlling the energization of the ignition coil including the main primary coil and the sub primary coil arranged on the primary side and the secondary coil arranged on the secondary side, the ignition coil can be used as the internal combustion engine. An electronic control device that controls the supply of electrical energy to the spark plug that discharges in the cylinder.
   When a predetermined superposition energization start time elapses after the discharge of the main primary coil is started, the energization of the sub-primary coil is started, and after the energization of the sub-primary coil is started, the internal combustion engine An electronic control device that controls the energization of the ignition coil so that the energization of the sub-primary coil is terminated when a predetermined superimposition energization period corresponding to the rotation speed has elapsed.
2. In the electronic control device according to claim 1,
   The superimposed energization start time is an electronic control device determined based on a measurement result of a re-discharge time indicating a time from the start of discharge to re-discharge when the spark plug is discharged in the cylinder of the internal combustion engine.
3. In the electronic control device according to claim 2,
   The superimposed energization start time is electronically controlled so that the number of occurrences of the re-discharge is maximized within the superimposed energization period in the distribution of each measurement result when the re-discharge time is measured a plurality of times. Device.
4. In the electronic control device according to claim 3,
   In the measurement of the re-discharge time, an electronic control device that detects the occurrence of the re-discharge based on the differential value of the secondary voltage when the voltage of the secondary coil is measured as the secondary voltage.
5. In the electronic control device according to any one of claims 1 to 4.
   If the voltage of the secondary coil is larger than the predetermined upper limit voltage or less than the predetermined lower limit voltage when the superposition energization start time has elapsed after the discharge of the main primary coil is started, the sub An electronic control device that does not energize the primary coil.
6. In the electronic control device according to claim 5,
   The upper limit voltage and the lower limit voltage are based on the measurement result of the re-discharge voltage indicating the voltage of the secondary coil at the time immediately before the occurrence of the re-discharge when the spark plug is discharged in the cylinder of the internal combustion engine. The electronic control device to be determined.
7. In the electronic control device according to claim 6,
   The upper limit voltage and the lower limit voltage are determined so that the number of occurrences of the re-discharge is maximized within a predetermined voltage range in the distribution of each measurement result when the re-discharge voltage is measured a plurality of times. Electronic control device.
8. In the electronic control device according to claim 1,
   An electronic control device having a superimposed energization period of 0.5 milliseconds when the rotation speed of the internal combustion engine is 2400 rpm.
9. In the electronic control device according to claim 1,
   It has a timer circuit that sets a timer value according to the superimposed energization period and ends the energization of the sub-primary coil when the elapsed time from the start of energization of the sub-primary coil reaches the timer value. Electronic control device.
10. In the electronic control device according to claim 9,
    The timer circuit is an electronic control device that sets the timer value based on the charging period of the main primary coil or the discharge cycle of the spark plug.
11. In the electronic control device according to claim 1,
    An electronic control device that changes the superimposed energization start time based on the time change of the voltage of the secondary coil.
12. By controlling the energization of the ignition coil including the main primary coil and the sub primary coil arranged on the primary side and the secondary coil arranged on the secondary side, the ignition coil can be used as the internal combustion engine. An electronic control device that controls the supply of electrical energy to the spark plug that discharges in the cylinder.
    When a predetermined superposition energization start time has elapsed since the discharge of the main primary coil was started, the energization of the sub-primary coil is started, and after the energization of the sub-primary coil is started, the predetermined superimposition energization is started. The energization of the ignition coil is controlled so that the energization of the sub-primary coil is terminated when the period elapses.
    An electronic control device that increases the superimposed energization start time 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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