Electronic Controls

Abstract

An electronic control unit controls the supply of electrical energy from the ignition coil to a spark plug for discharging in a cylinder of an internal combustion engine by controlling the energization of an ignition coil. The ignition coil includes a main primary coil and a sub-primary coil respectively arranged on a primary side, and a secondary coil arranged on a secondary side. The electronic control unit controls the energization of the ignition coil so that the energization of the sub-primary coil is started when a prescribed overlapping energization start time has passed after the start of discharge of the main primary coil, and the energization of the sub-primary coil is terminated when a prescribed overlapping energization period corresponding to the speed of the internal combustion engine has passed after the start of energization of the sub-primary coil.

Description

Technical Field

[0001] The present invention relates to an electronic control device. Background Art

[0002] In recent years, in order to improve vehicle fuel efficiency, a control device for an internal combustion engine has been developed that incorporates a technique for operating the engine by burning a mixture thinner than the theoretical air-fuel ratio and a technique for taking in part of the exhaust gas after combustion and re-inhaling it.

[0003] In the control device of such an internal combustion engine, the amount of fuel and air in the combustion chamber will deviate from the theoretical value, which may easily cause the spark plug to ignite the fuel poorly. Therefore, there is a method of increasing the gas flow rate in the combustion chamber to increase the flow rate between the electrodes of the spark plug and form a longer discharge path, thereby extending the contact length between the discharge path and the gas to suppress poor ignition. However, if the flow rate between the electrodes of the spark plug is high, the frequency of blowing out the discharge path and the subsequent re-discharge will be high, making it difficult to form a longer discharge path.

[0004] In order to form a long discharge path, it is necessary to continue to supply current with a sufficient current after the discharge path is formed, so that the discharge path needs to be maintained for as long as possible. However, generally speaking, the internal energy of the ignition coil continues to decrease over time after the discharge starts, so the current required to maintain the discharge path is gradually unable to be supplied. As a result, the discharge path cannot be maintained during the combustion of the gas, and the problem of needing to discharge again arises.

[0005] Patent document 1 discloses a control device for an internal combustion engine, which uses an ignition coil having a main primary coil and a sub-primary coil. The main primary coil generates a discharge spark in the spark plug, and then compares the primary voltage with a threshold. When the voltage exceeds the threshold, the sub-primary coil superimposes the current.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2019 / 198119 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] In the technology disclosed in Patent Document 1, the energization time of the superimposed current varies with the magnitude of the primary voltage, so the heat generated by the ignition coil varies in each cycle of the internal combustion engine. In order to cope with such cyclic changes in heat generation, it is necessary to set a cooling capacity with an excessive margin for the ignition coil, which leads to the problem of increasing the volume and cost of the ignition coil.

[0011] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to suppress the increase in the volume and cost of the ignition coil and to achieve both improvement in the fuel efficiency of the internal combustion engine and suppression of misignition of the fuel.

[0012] Technical solutions adopted to solve technical problems

[0013] The electronic control device involved in the first embodiment of the present invention controls the supply of electrical energy from the ignition coil to the spark plug for discharging in the cylinder of the internal combustion engine by controlling the energization of the ignition coil. The ignition coil includes a main primary coil and a sub-primary coil respectively arranged on the primary side, and a secondary coil arranged on the secondary side. The electronic control device controls the energization of the ignition coil so that the energization of the sub-primary coil is started when a prescribed overlapping energization start time has passed after the start of discharge of the main primary coil, and the energization of the sub-primary coil is terminated when a prescribed overlapping energization period corresponding to the speed of the internal combustion engine has passed after the start of energization of the sub-primary coil.

[0014] The electronic control device involved in the second mode of the present invention controls the supply of electrical energy from the ignition coil to the spark plug for discharging in the cylinder of the internal combustion engine by controlling the energization of the ignition coil. The ignition coil includes a main primary coil and a sub-primary coil respectively arranged on the primary side, and a secondary coil arranged on the secondary side. The electronic control device controls the energization of the ignition coil so that the energization of the sub-primary coil is started when a prescribed overlapping energization start time has passed after the start of the discharge of the main primary coil, and the energization of the sub-primary coil is ended when a prescribed overlapping energization period has passed after the start of the energization of the sub-primary coil. The earlier the discharge start timing of the main primary coil becomes according to the operating state of the internal combustion engine, the more the overlapping energization start time is increased.

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to suppress an increase in the size and cost of an ignition coil, and to achieve both improvement in fuel efficiency of an internal combustion engine and suppression of fuel ignition failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram for explaining the main configuration of an internal combustion engine and an internal combustion engine control device according to the embodiment.

[0018] Figure 2 It is a partial enlarged view illustrating a spark plug.

[0019] Figure 3 It is a functional block diagram illustrating the functional structure of the control device according to the embodiment.

[0020] Figure 4 This is a diagram for explaining the relationship between the operating state of the internal combustion engine and the gas flow velocity around the spark plug.

[0021] Figure 5 It is a diagram for explaining the relationship between the discharge path between the electrodes of the spark plug and the flow velocity.

[0022] Figure 6 It is a diagram for explaining a circuit including a conventional ignition coil.

[0023] Figure 7 This is a diagram showing an example of a timing chart for explaining the relationship between a control signal input to an ignition coil and an output in conventional discharge control.

[0024] Figure 8 This is a diagram for explaining a circuit including an ignition coil according to the first embodiment.

[0025] Fig. 9 FIG. 1 is a diagram showing an example of a scatter diagram recording measurement results of the re-discharge voltage and the re-discharge time.

[0026] Fig.10 FIG. 2 is a diagram showing an example of a histogram recording the measurement results of the re-discharge time.

[0027] Fig.11 This is a diagram showing an example of a timing chart for explaining the relationship between a control signal input to the ignition coil and an output in the discharge control according to the first embodiment.

[0028] Fig.12 It is a figure explaining the effect of this invention.

[0029] Fig.13 This is an example of a flowchart for explaining a method for setting the overlap energization start time according to the first embodiment.

[0030] Fig.14 This is an example of a flowchart for explaining the control method of the sub-primary coil according to the first embodiment.

[0031] Fig.15 This is a diagram for explaining a circuit including an ignition coil according to the second embodiment.

[0032] Fig.16 This is an example of a flowchart for explaining a method for setting the overlap energization start time and the overlap energization voltage range according to the second embodiment.

[0033] Fig.17 This is an example of a flowchart for explaining a method for controlling the sub-primary coil according to the second embodiment.

[0034] Fig.18 This is a diagram for explaining a circuit including an ignition coil according to the third embodiment.

[0035] Fig.19 This is an example of map information indicating the relationship between the engine speed and the on-period of the ignition signal SA.

[0036] Fig. 20 2 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.

[0037] Fig.21 This is an example of a flowchart for explaining a method for controlling a sub-primary coil according to the third embodiment.

[0038] Fig. 22 This is a diagram showing an example of a timing chart for explaining the relationship between a control signal input to the ignition coil and an output in the discharge control according to the fourth embodiment.

[0039] Fig.23 This is an example of a graph showing the relationship between the gas flow rate between the electrodes and the correction added value for the rising timing of the ignition signal SB.

[0040] Fig.24 This is an example of a flowchart for explaining a method for controlling a sub-primary coil according to the fourth embodiment. DETAILED DESCRIPTION

[0041] Next, a control device for an internal combustion engine according to an embodiment of the present invention will be described.

[0042] Next, a control device 1 as one form of an electronic control device according to an embodiment of the present invention will be described. In this embodiment, the control device 1 will be used to control the discharge (ignition) of the spark plugs 200 provided in the cylinders 150 of the four-cylinder internal combustion engine 100.

[0043] Hereinafter, in the present embodiment, a combination of a part or all of the structure of the internal combustion engine 100 and a part or all of the structure of the control device 1 is referred to as the control device 1 of the internal combustion engine 100 .

[0044] [internal combustion engine]

[0045] Figure 1 It is a diagram for explaining the main structure of the internal combustion engine 100 and the ignition device for the internal combustion engine.

[0046] Figure 2 It is a partially enlarged view illustrating electrodes 210 and 220 of the spark plug 200 .

[0047] In the internal combustion engine 100, air sucked from the outside circulates through the air cleaner 110, the intake pipe 111, and the intake manifold 112, and flows into each cylinder 150 when the intake valve 151 is opened. The amount of air flowing into each cylinder 150 is adjusted by the throttle valve 113, and the amount of air adjusted by the throttle valve 113 is measured by the flow sensor 114.

[0048] The throttle valve 113 is provided with a throttle valve opening sensor 113a for detecting the opening of the throttle valve. The opening information of the throttle valve 113 detected by the throttle valve opening sensor 113a is output to the control device (Electronic Control Unit: ECU) 1.

[0049] In addition, the throttle valve 113 uses an electronic throttle valve driven by an electric motor, but other methods may be used as long as the air flow rate can be appropriately adjusted.

[0050] The temperature of the gas flowing into each cylinder 150 is detected by the intake air temperature sensor 115 .

[0051] The crank angle sensor 121 is provided radially outside the ring gear 120 attached to the crankshaft 123. The crank angle sensor 121 detects the rotation angle of the crankshaft 123. In the present embodiment, the crank angle sensor 121 detects the rotation angle of the crankshaft 123, for example, every 10° and every combustion cycle.

[0052] The water temperature sensor 122 is provided on a 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.

[0053] In addition, an accelerator position sensor (APS) 126 is provided in the vehicle, which detects the displacement (depression amount) of the accelerator pedal 125. The driver's request torque is detected by the accelerator position sensor 126. The driver's request torque 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 the request torque.

[0054] The fuel stored in the fuel tank 130 is sucked and pressurized by the fuel pump 131, and then flows through the fuel pipe 133 provided with the pressure regulator 132, and is guided to the fuel injection valve (injector) 134. The fuel output from the fuel pump 131 is adjusted to a prescribed pressure by the pressure regulator 132, and is injected into each cylinder 150 from the fuel injection valve (injector) 134. As a result of the pressure regulation by the pressure regulator 132, the excess fuel is returned to the fuel tank 130 via a return pipe (not shown).

[0055] A combustion pressure sensor (Cylinder Pressure Sensor: CPS, also referred to as an in-cylinder pressure sensor) 140 is provided on a cylinder head (not shown) of the internal combustion engine 100. The combustion pressure sensor 140 is provided in each cylinder 150 and detects the pressure in the cylinder 150 (combustion pressure).

[0056] The combustion pressure sensor 140 uses a piezoelectric type or a gauge type pressure sensor, and is capable of detecting the combustion pressure (in-cylinder pressure) in the cylinder 150 in a wide temperature range.

[0057] Each cylinder 150 is provided with an exhaust valve 152 and an exhaust manifold 160 for discharging 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, the exhaust gas is discharged from the cylinder 150 to the exhaust manifold 160. The exhaust gas passes through the exhaust manifold 160, is purified by the three-way catalyst 161, and is discharged into the atmosphere.

[0058] The 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 exhausted from each cylinder 150.

[0059] In addition, 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 detection signal near the theoretical air-fuel ratio. In the present embodiment, the downstream air-fuel ratio sensor 163 is, for example, an O2 sensor.

[0060] In addition, spark plugs 200 are provided at the upper part of each cylinder 150. The discharge (ignition) of the spark plugs 200 ignites the mixture of air and fuel in the cylinder 150, and explosion occurs in the cylinder 150, thereby pressing the piston 170. The crankshaft 123 rotates when the piston 170 is pressed.

[0061] An ignition coil 300 for generating electric energy (voltage) to be supplied to the spark plug 200 is connected to the spark plug 200. According to the voltage generated in the ignition coil 300, discharge is generated between the center electrode 210 and the outer electrode 220 of the spark plug 200 (see Figure 2 ).

[0062] like Figure 2 As shown, in the spark plug 200 , the center electrode 210 is supported in an insulated state by the insulator 230 . A predetermined voltage (for example, 20,000 V to 40,000 V in the present embodiment) is applied to the center electrode 210 .

[0063] The outer electrode 220 is grounded. When a predetermined voltage is applied to the center electrode 210 , discharge (ignition) occurs between the center electrode 210 and the outer electrode 220 .

[0064] In the spark plug 200, the voltage that causes dielectric breakdown of gas components and generates discharge (ignition) varies depending on the state of gas between the center electrode 210 and the outer electrode 220 and the cylinder pressure. The voltage that generates this discharge is called dielectric breakdown voltage.

[0065] The discharge control (ignition control) of the spark plug 200 is performed by an ignition control section 83 of the control device 1 described later.

[0066] return Figure 1 The control device 1 outputs output signals from various sensors such as the throttle opening sensor 113a, the flow sensor 114, the crank angle sensor 121, the accelerator position sensor 126, the water temperature sensor 122, and the combustion pressure sensor 140 to the control device 1. 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 output to the cylinder 150, the amount of fuel injection, the ignition timing of the spark plug 200, and the like.

[0067] [Hardware structure of the control device]

[0068] Next, the overall configuration of the hardware of the control device 1 will be described.

[0069] like Figure 1 As shown, the control device 1 has an analog input unit 10, a digital input unit 20, an A / D (Analog / Digital) conversion unit 30, a RAM (Random Access Memory) 40, an MPU (Micro-Processing Unit) 50, a ROM (Read Only Memory) 60, an I / O (Input / Output) port 70 and an output circuit 80.

[0070] Analog output signals from various sensors such as the throttle opening sensor 113a, the flow sensor 114, the accelerator position sensor 126, the upstream air-fuel ratio sensor 162, the downstream air-fuel ratio sensor 163, the combustion pressure sensor 140 and the water temperature sensor 122 are input to the analog input unit 10.

[0071] The A / D converter 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 converter 30 after signal processing such as noise removal, and are stored in the RAM 40 .

[0072] A digital output signal from the crank angle sensor 121 is input to the digital input unit 20 .

[0073] The I / O port 70 is connected to the digital input unit 20 , and a digital output signal input to the digital input unit 20 is stored in the RAM 40 via the I / O port 70 .

[0074] Each output signal stored in the RAM 40 is subjected to calculation processing by the MPU 50 .

[0075] The MPU 50 executes a control program (not shown) stored in the ROM 60, thereby performing arithmetic processing on the output signals stored in the RAM 40 according to the control program. The MPU 50 calculates control values ​​that define the operation amounts of various actuators (e.g., the throttle valve 113, the pressure regulator 132, the spark plug 200, etc.) that drive the internal combustion engine 100 according to the control program, and temporarily stores the control values ​​in the RAM 40.

[0076] The control value that defines the amount of operation of the actuator stored in the RAM 40 is output to the output circuit 80 via the I / O port 70 .

[0077] The output circuit 80 is provided with an ignition control unit 83 (see Figure 3 ) functions, etc.

[0078] [Functional blocks of control device]

[0079] Next, the functional configuration of the control device 1 according to the embodiment of the present invention will be described.

[0080] Figure 3 1 is a functional block diagram for explaining the functional configuration of the control device 1 according to one embodiment of the present invention. Each function of the control device 1 is realized by the output circuit 80 when the MPU 50 executes a control program stored in the ROM 60 , for example.

[0081] like Figure 3 As shown, 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 .

[0082] The overall control portion 81 is connected to the accelerator position sensor 126 and the combustion pressure sensor 140 (CPS), and receives a requested torque (acceleration signal S1 ) from the accelerator position sensor 126 and an output signal S2 from the combustion pressure sensor 140 .

[0083] The overall control unit 81 controls the fuel injection control unit 82 and the ignition control unit 83 overall based on the requested torque (acceleration signal S1 ) from the accelerator position sensor 126 and the output signal S2 from the combustion pressure sensor 140 .

[0084] The fuel injection control unit 82 is connected to a cylinder discrimination unit 84 for discriminating each cylinder 150 of the internal combustion engine 100, an angle information generating unit 85 for measuring the crank angle of the crankshaft 123, and a speed information generating unit 86 for measuring the engine speed, and receives cylinder discrimination information S3 from the cylinder discrimination unit 84, crank angle information S4 from the angle information generating unit 85, and engine speed information S5 from the speed information generating unit 86.

[0085] In addition, the fuel injection control unit 82 is connected to an intake amount measuring unit 87 for measuring the intake amount of air into the cylinder 150, a load information generating unit 88 for measuring the engine load, and a water temperature measuring unit 89 for measuring the temperature of the engine cooling water, and receives intake amount information S6 from the intake amount measuring unit 87, engine load information S7 from the load information generating unit 88, and cooling water temperature information S8 from the water temperature measuring unit 89.

[0086] The fuel injection control unit 82 calculates the injection amount and injection time of the fuel injected from the fuel injection valve 134 based on the received various information (fuel injection valve control information S9), and controls the fuel injection valve 134 based on the calculated injection amount and injection time.

[0087] The ignition control unit 83 is connected to the cylinder determination unit 84 , the angle information generation unit 85 , the rotation speed information generation unit 86 , the load information generation unit 88 , and the water temperature measurement unit 89 in addition to the overall control unit 81 , and receives various information therefrom.

[0088] Based on the received various information, the ignition control unit 83 calculates the amount of current (conduction angle) supplied to the primary coil (not shown) of the ignition coil 300 , the time to start supplying current, and the time to cut off the current supplied to the primary coil (ignition time).

[0089] The ignition control unit 83 outputs an ignition signal SA to the primary coil of the ignition coil 300 based on the calculated conduction angle, conduction start time, and ignition time, thereby performing discharge control (ignition control) through the spark plug 200 .

[0090] The function of the ignition control unit 83 to perform ignition control of the spark plug 200 using the ignition signal SA at least corresponds to the internal combustion engine control device of the present invention.

[0091] Figure 4 2 is a diagram for explaining the relationship between the operating state of the internal combustion engine 100 and the gas flow velocity around the spark plug 200. Figure 4 As shown in FIG. 1 , generally, the higher the engine speed and load, the higher the gas flow velocity in the cylinder 150, and the gas around the spark plug 200 also has a high flow velocity. Therefore, the gas flows at a high speed between the center electrode 210 and the outer electrode 220 of the spark plug 200. In addition, in the internal combustion engine 100 that performs exhaust gas recirculation (EGR), for example, Figure 4 As shown in FIG. 1 , the EGR rate is set according to the relationship between the engine speed and the load. In addition, as the EGR rate is set higher, the higher the high EGR region is, the lower the fuel consumption and the lower the exhaust gas can be achieved, but the spark plug 200 is more likely to have ignition failure.

[0092] Figure 5 1 is a diagram illustrating the relationship between the discharge path and flow rate of the spark plug 200 between the electrodes. When a high voltage is generated in the secondary coil of the ignition coil 300 and insulation breakdown occurs between the center electrode 210 and the outer electrode 220 of the spark plug 200, a discharge path is formed between the electrodes of the spark plug 200 until the current flowing between these electrodes becomes less than a constant value. When the combustible gas contacts this discharge path, the flame core grows until it burns. Since the discharge path moves under the influence of the gas flow between the electrodes, the higher the gas flow rate, the longer the discharge path is formed in a short time, and the lower the gas flow rate, the shorter the discharge path. Figure 5 (a) shows an example of the discharge path 211 when the gas flow rate is high, Figure 5 (b) shows an example of the discharge path 212 when the gas flow rate is low.

[0093] When the internal combustion engine 100 is operated at a high EGR rate, even if the combustible gas contacts the discharge path, the probability of the flame core growing is reduced, so it is necessary to increase the chance of the combustible gas contacting the discharge path. As described above, since the discharge path is generated by breaking down the insulation of the gas, if the current required to maintain the discharge path is constant, it is necessary to output power corresponding to the length of the discharge path. Therefore, preferably, when the gas flow rate is high, the ignition coil 300 is energized and controlled so that a large amount of power is output from the ignition coil 300 to the spark plug 200 in a short time, thereby forming a spark plug 200 as shown in FIG. Figure 5(a) shows a longer discharge path 211, thereby obtaining an opportunity to contact with a larger space of gas. On the other hand, when the gas flow rate is low, it is preferred to control the energization of the ignition coil 300 so that a small power is continuously output from the ignition coil 300 to the spark plug 200 for a long time, thereby maintaining the ignition coil 300 as shown in FIG. Figure 5 The formation of the shorter discharge path 212 as (b) provides an opportunity for contact with the gas passing near the electrode of the spark plug 200 for a longer period of time.

[0094] [Circuit of conventional ignition coil]

[0095] Next, before describing the embodiment of the present invention, a conventional ignition coil will be described.

[0096] Figure 6 The circuit 400C is a diagram for explaining a conventional ignition coil 300C as a comparative example of the present invention. In the circuit 400C, the ignition coil 300C includes a primary coil 310 wound with a predetermined number of turns and a secondary coil 320 wound with a larger number of turns than the primary coil 310 .

[0097] One end of the primary side coil 310 is connected to the DC power supply 330 . Therefore, a prescribed voltage (for example, 12 V) is applied to the primary side coil 310 .

[0098] The other end of the primary side coil 310 is connected to the igniter 340 and grounded via the igniter 340. In the igniter 340, a transistor, a field effect transistor (Field Effect Transistor: FET), or the like is used.

[0099] 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 in a power-on state, and current flows between the collector (C) terminal and the emitter (E) terminal. Therefore, the ignition signal SA is output from the ignition control unit 83 via the igniter 340 to the primary side coil 310 of the ignition coil 300 via the igniter 340, and current flows through the primary side coil 310, and electricity (electrical energy) is stored.

[0100] When the output of the ignition signal SA from the ignition control unit 83 stops and the current flowing through the primary side coil 310 is cut off, a high voltage corresponding to the coil turns ratio for the primary side coil 310 is generated in the secondary side coil 320 .

[0101] The high voltage generated in the secondary coil 320 by the ignition signal SA is applied to the spark plug 200 (center electrode 210), thereby generating a potential difference between the center electrode 210 and the outer electrode 220 of the spark plug 200. When the potential difference generated between the center electrode 210 and the outer electrode 220 is greater than the insulation breakdown voltage Vm of the gas (the mixture in the cylinder 150), the gas component is broken down, and discharge is generated between the center electrode 210 and the outer electrode 220, so that the fuel (mixture) is ignited (burned).

[0102] In the comparative example, the ignition control unit 83 controls the energization of the ignition coil 300A using the ignition signal SA by the operation of the circuit 400C as described above. Thus, ignition control for controlling the spark plug 200 is performed.

[0103] [Conventional discharge control of ignition coil]

[0104] Next, the conventional discharge control of the ignition coil will be described. Figure 7 This is a diagram showing an example of a timing chart for explaining the relationship between a control signal input to an ignition coil and an output in conventional discharge control. Figure 7 The timing chart is an example of a case where the spark plug 200 is discharged using the conventional ignition coil 300C when the gas flow rate is high. Figure 7 FIG. 8 shows the relationship between the ignition signal SA output from the ignition control unit 83, the primary current I1 flowing through the primary coil 310 according to the ignition signal SA, the electric energy E accumulated in the ignition coil 300C, the secondary current I2 flowing through the secondary coil 320, and the secondary voltage V2 generated in the secondary coil 320. Figure 6 As shown, the secondary current I2 and the secondary voltage V2 are measured between the spark plug 200 and the ignition coil 300C. In addition, the primary current I1 is measured between the DC power supply 330 and the ignition coil 300C.

[0105] When the ignition signal SA changes to HIGH, the igniter 340 energizes the primary coil 310, and the primary current I1 increases. While the primary coil 310 is energized, the electric energy E in the ignition coil 300C increases with time.

[0106] Thereafter, when the ignition signal SA becomes LOW, the igniter 340 cuts off the energization of the primary side coil 310. Therefore, an electromotive force is generated in the secondary side coil 320, and the electric energy E starts to be supplied from the ignition coil 300C to the spark plug 200. When the insulation between the electrodes of the spark plug 200 is broken down, the discharge of the spark plug 200 starts. The discharge of the spark plug 200 accompanied by such insulation breakdown is called capacitive discharge. After the discharge of the spark plug 200 starts, the electric energy E in the ignition coil 300C decreases with time, maintaining the discharge of the spark plug 200. The discharge of the spark plug 200 not accompanied by such insulation breakdown is called inductive discharge.

[0107] The secondary current I2 rises significantly during capacitor discharge. The secondary current I2 caused by the capacitor discharge ends in a short time. When the discharge of the spark plug 200 begins and a discharge path is formed between the electrodes, the secondary current I2 drops sharply and decreases with time during the subsequent inductive discharge. Since the discharge path is extended along 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 varies according to the flow rate of the gas between the electrodes of the spark plug 200.

[0108] When the secondary current I2 is between the minimum value required to maintain the discharge path and the maximum value at which discharge is impossible, the spark plug 200 repeatedly blows out the discharge path and discharges again. The range of the secondary current I2 that repeatedly blows out the discharge path and discharges again is hereinafter referred to as the "intermittent operation area". That is, when the secondary current I2 enters the intermittent operation area, the discharge path cannot be maintained, and the discharge path is blown out by the airflow, thereby interrupting the discharge of the spark plug 200. At this time, even if the discharge path disappears, the electric energy E in the ignition coil 300C still remains, so a re-discharge (restrike: re-ignition) accompanied by capacitor discharge occurs in the spark plug 200. Figure 7 In the example of FIG. 1 , the first discharge is 1 time and the second discharge is 3 times, and the number of capacitor discharges is 4 times.

[0109] When the electric energy E in the ignition coil 300C decreases, the secondary current I2 also decreases. When the secondary current I2 becomes less than the maximum value at which discharge is impossible, the discharge of the spark plug 200 stops.

[0110] In the present invention, an ignition coil 300 having two primary side coils is used to replace Figure 6 The ignition coil 300C described above is controlled to discharge the ignition coil 300, thereby achieving discharge of the spark plug 200 with the number of capacitor discharges suppressed.

[0111] [Embodiment 1: Circuit of Ignition Coil]

[0112] Next, the electric circuit 400 including the ignition coil 300 according to the first embodiment of the present invention will be described.

[0113] Figure 8 4 is a diagram for explaining a circuit 400 including an ignition coil 300 according to Embodiment 1 of the present invention. In the circuit 400, the ignition coil 300 includes two types of primary coils 310 and 360 respectively wound with a predetermined number of turns, and a secondary coil 320 wound with a number of turns greater than that of the primary coils 310 and 360. Here, when the spark plug 200 ignites, power from the primary coil 310 is first supplied to the secondary coil 320, and power from the primary coil 360 is supplied to the secondary coil 320 in superposition with the power. Therefore, hereinafter, the primary coil 310 is referred to as a "main primary coil", and the primary coil 360 is referred to as a "sub-primary coil". In addition, the current flowing through the main primary coil 310 is referred to as a "main primary current", and the current flowing through the sub-primary coil 360 is referred to as a "sub-primary current".

[0114] One end of the main primary coil 310 is connected to the DC power supply 330 . Therefore, a prescribed voltage (for example, 12 V in the embodiment) is applied to the main primary coil 310 .

[0115] The other end of the main primary coil 310 is connected to the igniter 340 and grounded via the igniter 340. For the igniter 340, a transistor, a field effect transistor (FET) or the like is used.

[0116] 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 in a power-on state, and current flows between the collector (C) terminal and the emitter (E) terminal. Therefore, the ignition signal SA is output from the ignition control unit 83 via the igniter 340 to the main primary coil 310 of the ignition coil 300, and the main primary current flows through the main primary coil 310, and electricity (electrical energy) is stored.

[0117] When the output of the ignition signal SA from the ignition control portion 83 stops and the main primary current flowing through the main primary coil 310 is cut off, a high voltage corresponding to the coil turns ratio for the main primary coil 310 is generated in the secondary side coil 320 .

[0118] One end of the sub-primary coil 360 is common to the main primary coil 310 and is connected to the DC power supply 330. Therefore, a predetermined voltage (for example, 12V in the embodiment) is applied to the sub-primary coil 360.

[0119] The other end of the sub-primary coil 360 is connected to the igniter 350 and grounded via the igniter 350. For the igniter 350, a transistor, a field effect transistor (FET) or the like is used.

[0120] 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 and off of the igniter 350. The ignition signal SB output from the ignition 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 in a power-on state corresponding to the voltage change of the ignition signal SB, and a current corresponding to the voltage change of the ignition signal SB flows between the collector (C) terminal and the emitter (E) terminal. Therefore, the ignition signal SB is output from the ignition control unit 83 via the igniter 350 to the secondary primary coil 360 of the ignition coil 300, and the secondary primary current flows through the secondary primary coil 360, and electric power (electric energy) is generated.

[0121] When the output of the ignition signal SB from the phase control portion 380 changes and the sub-primary current flowing through the sub-primary coil 360 changes, a high voltage corresponding to the coil turns ratio for the sub-primary coil 360 is generated in the secondary side coil 320 .

[0122] The high voltage generated in the secondary coil 320 by the ignition signal SA is added 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), thereby generating a potential difference between the center electrode 210 and the outer electrode 220 of the spark plug 200. When the potential difference generated between the center electrode 210 and the outer electrode 220 is equal to or greater than the insulation breakdown voltage Vm of the gas (the mixture in the cylinder 150), the gas component is broken down, and discharge is generated between the center electrode 210 and the outer electrode 220, thereby igniting the fuel (the mixture).

[0123] The phase control unit 380 performs output control of the ignition signal SB so that the ignition signal SB is raised at a period A starting from the falling period S of the ignition signal SA and a predetermined overlap energization start time has passed therefrom, and then the ignition signal SB is lowered at a period B after a predetermined overlap energization period has passed. Thus, the power from the auxiliary primary coil 360 is supplied to the spark plug 200 in an overlapping manner with the power supplied from the main primary coil 310, and the discharge path formed between the center electrode 210 and the outer electrode 220 is maintained. In addition, a specific output control method of the ignition signal SB will be described later.

[0124] The ignition control unit 83 controls the energization of the ignition coil 300 using the ignition signals SA and SB by the operation of the circuit 400 as described above. Thus, the ignition control for controlling the spark plug 200 is performed.

[0125] In addition, the phase control unit 380 may not 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 either case, the phase control unit 380 operates according to the control of the ignition control unit 83, so it can be said that the ignition control unit 83 controls the energization of the ignition coil 300.

[0126] [Embodiment 1: Discharge Control of Ignition Coil]

[0127] Next, the discharge control of the ignition coil involved in the first embodiment of the present invention is described. In this 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 overlapping energization start time and overlapping energization period. The overlapping energization start time refers to the time from the falling period S of the ignition signal SA to the rising period A of the ignition signal SB, that is, the time from the start of the discharge of the main primary coil 310 according to the ignition signal SA to the start of the energization of the auxiliary primary coil 360. On the other hand, the overlapping energization period refers to the time from the rising period A to the falling period B of the ignition signal SB, that is, the time from the start of energization of the auxiliary primary coil 360 to the end of energization. These times are set based on the results of measuring the occurrence state of re-discharge when the spark plug 200 discharges in the cylinder 150 during the development stage of the ignition control unit 83. An example of its specific method is described below.

[0128] First, in Figure 8 In the circuit 400 shown, a voltage sensor is provided between the spark plug 200 and the ignition coil 300, and the voltage sensor is used to detect the secondary voltage V2 when the spark plug 200 is discharged in the cylinder 150. Figure 6The circuit 400C shown in FIG. 4 is used to detect the secondary voltage V2 when the spark plug 200 is discharged in the cylinder 150, instead of the circuit 400. Then, based on the value of the secondary voltage V2 obtained, the secondary voltage V2 at the time point immediately before the re-discharge of the spark plug 200 occurs (hereinafter referred to as the "re-discharge voltage") is measured, and based on the period of measuring the re-discharge voltage, the time from the start of the discharge of the spark plug 200 to the re-discharge (hereinafter referred to as the "re-discharge time") is measured.

[0129] For example, in Figure 7 In the waveform of the secondary voltage V2 shown, 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 drops sharply after the discharge starts, is defined as V2max. By respectively finding the value of V2max and the time from the drop of the ignition signal SA to the detection of V2max (V2max period) from the detection result of the secondary voltage V2, it is possible to measure the re-discharge voltage and the re-discharge time. In addition, when detecting V2max, the time differential dV2 / dt of the secondary voltage V2 can also be found, and the value of the time differential dV2 / dt can be compared with a predetermined threshold value. In this way, the point where the secondary voltage V2 drops sharply can be easily detected as V2max, and the re-discharge time can be measured.

[0130] Based on the detection result of the secondary voltage V2, the re-discharge voltage and the re-discharge time are measured multiple times, and the measurement results are statistically processed to determine the setting values ​​of the overlap power-on start time and the overlap power-on period. Fig. 9 , Fig.10 This method will be described.

[0131] Fig. 9 The figure shows an example of a scatter diagram recording the measurement results of the re-discharge voltage and the re-discharge time. In this scatter diagram, the horizontal axis represents the V2max period starting from the falling period S of the ignition signal SA, that is, the re-discharge time, and the vertical axis represents the V2max value, that is, the re-discharge voltage.

[0132] During the operation of the internal combustion engine 100, the gas flow between the electrodes of the spark plug 200 in the cylinder 150 and the temperature of the electrodes vary in each combustion cycle. Therefore, the values ​​of V2max and V2max period are as follows: Fig. 9As shown, it varies in each combustion cycle rather than being constant. However, when an attempt is made to supply overlapping current to the spark plug 200 through the secondary primary coil 360 within the range of all re-discharge times corresponding to the range of variation of the Vmax period, the secondary primary coil 360 is energized excessively. As a result, the power consumption and heat generation of the ignition coil 300 are excessive, and in order to install the ignition coil 300, the cooling capacity of the ignition coil 300 must be larger than necessary, which may lead to an increase in volume and cost.

[0133] Therefore, in the present embodiment, in the distribution of each measurement result when the re-discharge time is measured a plurality of times, the heating-allowable energization period of the auxiliary primary coil 360 is set as the overlap energization period, and the overlap energization start time is set so that the number of re-discharges of the spark plug 200 during the overlap energization period is maximized. Therefore, it is not necessary to increase the cooling capacity of the ignition coil 300, and the re-discharge in the spark plug 200 is suppressed as much as possible, and both the suppression of the power consumption of the ignition coil 300 and the extension of the discharge path between the electrodes of the spark plug 200 are achieved.

[0134] Specifically, for example, in Fig. 9 In the scatter diagram shown, line segments 91 and 92 are set corresponding to the rising period A and the falling period B of the ignition signal SB, respectively, and the interval between the line segments 91 and 92 is fixed to match the energization period of the secondary primary coil 360 that is allowable 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 horizontally on the scatter diagram to search for the position where the number of measurement points entering between the line segments 91 and 92 is the largest. The overlapping energization start time can be set based on the position of the line segment 91 thus searched. In addition, when there is no problem in the heat generation of the ignition coil 300, the overlapping energization start time can be set so that all measurement points enter between the line segments 91 and 92.

[0135] In addition, Fig. 9 In the scatter diagram shown, 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. For example, based on the interval between the line segments 93 and 94, the number of measurement points entering between the line segments 93 and 94, etc., the positions of the line segments 93 and 94 are determined to meet the prescribed conditions. In this case, all the measurement points can enter between the line segments 93 and 94. According to the positions of the line segments 93 and 94 set in this way, the lower limit voltage C and the upper limit voltage D of the secondary voltage V2 are set, and these can be used to control the ignition signal SB. In addition, the control method of 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.

[0136] Alternatively, the measurement results of the re-discharge time may be recorded in a histogram, and the overlap energization start time may be set using the histogram. Fig.10 1 is a diagram showing an example of a histogram recording the measurement results of the re-discharge time. In the histogram, the horizontal axis represents the V2max period starting from the falling period 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 for which the value of each V2max period was measured, that is, the frequency of each measurement result representing the re-discharge time.

[0137] Even in Fig.10 In the histogram shown, it is also possible to Fig. 9 The overlapping energization start time is set in the same way as the scatter diagram of the ignition signal SB. That is, the line segments 95 and 96 corresponding to the rising period A and the falling period B of the ignition signal SB are set, respectively, and the interval between the line segments 95 and the line segment 96 is fixed to match the energization period of the secondary primary coil 360 that is allowable in terms of heat according to the rotation speed of the internal combustion engine 100. In this state, the line segments 95 and 96 are moved horizontally on the histogram to search for the position where the total value (frequency) of the number of combustion cycles entering between the line segments 95 and the line segments 96 is the largest. The overlapping energization start time can be set based on the position of the line segment 95 searched in this way. In addition, when there is no problem with the heat generation of the ignition coil 300, all areas of the histogram distribution can be set as the overlapping energization start time.

[0138] The above explains the use of Fig. 9 The scatter plot and Fig.10 The method for setting the overlapped energization start time when recording the measurement results of the re-discharge time in a histogram is described below. However, when recording the measurement results of the re-discharge time using other methods, the same method can also be used. Fig. 9 , Fig.10 The overlapping energization start time is set similarly. That is, preferably, in the distribution of the measurement results of the re-discharge time recorded by any method, the overlapping energization start time is set so that the number of times the re-discharge occurs in a predetermined overlapping energization period is maximized.

[0139] Fig.11 This is a diagram showing an example of a timing chart for explaining the relationship between a control signal input to the ignition coil and an output in the discharge control according to the first embodiment of the present invention. Fig.11 The timing chart is an example of a case where the spark plug 200 is discharged using the ignition coil 300 of the present embodiment when the gas has a high flow velocity. Fig.11The diagram shows the relationship between the ignition signal SA output from the ignition control unit 83, the main primary current I1 flowing through the main primary coil 310 according to the ignition signal SA, the ignition signal SB output from the phase control unit 380, the secondary primary current I3 flowing through 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 through the secondary side coil 320 and the secondary voltage V2 generated in the secondary side coil 320.

[0140] When the ignition signal SA changes to HIGH, the igniter 340 energizes the main primary coil 310, and the main primary current I1 increases. While the main primary coil 310 is energized, the electric energy E in the ignition coil 300C increases with time.

[0141] Thereafter, when the ignition signal SA becomes LOW during the falling period S, the igniter 340 cuts off the energization of the main primary coil 310. Therefore, an electromotive force is generated in the secondary side coil 320, and the electric energy E starts to be supplied from the ignition coil 300 to the spark plug 200. When the insulation between the electrodes of the spark plug 200 is broken down, the discharge (capacitive discharge) of the spark plug 200 starts. After the discharge of the spark plug 200 starts, the electric energy E in the ignition coil 300 decreases with time, and the discharge (inductive discharge) of the spark plug 200 is maintained.

[0142] The secondary current I2 and the secondary voltage V2 rise significantly during capacitor discharge. The rise of the secondary current I2 and the secondary voltage V2 generated by the capacitor discharge ends in a short time. When the discharge of the spark plug 200 begins and a discharge path is formed between the electrodes, the secondary current I2 and the secondary voltage V2 drop sharply respectively. During the subsequent inductive discharge, the secondary current I2 decreases with time. On the other hand, since the discharge path is extended along with the flow of the gas, the secondary voltage V2 rises with the passage of time. At this time, the size of the secondary current I2 required to maintain the discharge path varies according to the flow rate of the gas between the electrodes of the spark plug 200.

[0143] The phase control unit 380 turns on the ignition signal SB at a period A after a predetermined overlapping energization start time has passed since the falling period S when the ignition signal SA changes from HIGH to LOW. Thereafter, the ignition signal SB is turned off at a period B after a predetermined overlapping energization period has passed since the period A. As described above, the overlapping energization start time and overlapping energization period used in the control of the ignition signal SB are pre-set in the phase control unit 380. That is, the overlapping 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. In addition, the superimposed energization period is pre-set based on the energization period of the secondary primary coil 360 that is allowable in terms of heat generation based on the rotation speed of the internal combustion engine 100.

[0144] During the period when 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 applied 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 increases to continue to maintain the discharge path. Therefore, the re-discharge (restrike: re-ignition) caused by the capacitor discharge is suppressed in the spark plug 200. Fig.11 In the example of FIG. 1 , the first discharge is 1 time and the second discharge is 1 time, and the number of capacitor discharges is 2 times.

[0145] In addition, the secondary current I2 when the ignition signal SB is output includes a current flowing through the secondary coil 320 via the main primary coil 310 and a current flowing through the secondary coil 320 via the sub-primary coil 360 .

[0146] Fig.12 1 is a diagram illustrating the effect of the present invention. Fig.12 In the figure, signal waveform 501 shows the waveform of ignition signal SB outputted by the method described in the above embodiment as the ignition signal for overlapping current of the present invention. In addition, the pulse width of ignition signal SB in signal waveform 501, that is, the overlapping power-on period from rising period A when ignition signal SB is turned on to falling period B when ignition signal SB is turned off, is determined according to the rotation speed of internal combustion engine 100. For example, when the rotation speed of internal combustion engine 100 is 2400 [rpm], the overlapping power-on period is 0.5 [msec]. On the other hand, signal waveform 502 shows the waveform of ignition signal SB outputted within the range of all re-discharge times that may be generated in spark plug 200, as an ignition signal for overlapping current of a comparative example. In addition, current waveforms 503 and 504 respectively show waveform examples of secondary current I2 flowing according to ignition signal SB shown by these signal waveforms 501 and 502.

[0147] A plot 505 shows the relationship between the amount of energy consumed by the ignition coil 300 and the combustion stability of the spark plug 200 due to the supply of the superimposed current corresponding to the ignition signal SB. In the plot 505, points 506 and 507 respectively represent the relationship between the amount of energy consumed 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. In addition, point 508 represents the relationship between the amount of energy consumed by the ignition coil 300 and the combustion stability in the spark plug 200 when the ignition signal SB is used. Figure 6 The relationship between energy consumption and connection stability in the previous example of circuit 400C.

[0148] By comparing point 506 and point 507, it can be found that the present invention and the comparative example are the same in terms of combustion stability (ignition performance), but the present invention has a significantly lower energy consumption (calorific value) than the comparative example. In addition, by comparing point 506 and point 508, it can be found that although the energy consumption (calorific value) of the present invention is slightly increased compared with the previous example, the combustion stability (ignition performance) is greatly improved.

[0149] As described above, by adopting the control method of the ignition coil 300 of the present invention, it is possible to achieve both the suppression of the power consumption of the ignition coil 300 and the suppression of the ignition failure of the spark plug 200. Therefore, it is possible to suppress the increase in the volume and cost of the ignition coil 300 and suppress the ignition failure of the gas caused by the spark plug 200.

[0150] [Implementation 1: Flow of Setting the Overlap Energization Start Time]

[0151] Next, a method of setting the overlap energization start time performed in advance in order to implement the above-mentioned discharge control will be described. Fig.13 FIG. 1 is an example of a flowchart for explaining a method for setting the overlap energization start time according to the first embodiment of the present invention. Fig.13 The processing shown in the flowchart is implemented in a prescribed experimental device or test device before the ignition coil 300 installed on the internal combustion engine 100 is connected to the ignition control unit 83 via the igniters 340 and 350 so that the ignition coil 300 starts actual operation, for example, during the development stage of the ignition coil 300 or before shipment.

[0152] When the spark plug 200 and the ignition coil 300 are respectively mounted at the predetermined positions of the experimental internal combustion engine 100, the Figure 8 When the circuit 400 is ready and the measurement of the secondary voltage V2 is ready, the process starts in step S101. Fig.13 The processing flow.

[0153] In step S102 , the secondary voltage V2 is detected when the ignition signal SA is output from the ignition control unit 83 to the ignition coil 300 to discharge the spark plug 200 .

[0154] In step S103, the time differential value dV2 / dt of the secondary voltage V2 is calculated and compared with a predetermined threshold value. If 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 a re-discharge has occurred, and the process proceeds to step S104. On the other hand, if dV2 / dt does not exceed the threshold value, the process returns to step S102 and the secondary voltage V2 is continuously detected.

[0155] In the present embodiment, through the processing of the above-mentioned step S103, based on the time differential dV2 / dt of the secondary voltage V2, it is detected that the discharge path formed between the electrodes of the spark plug 200 is blown out and a re-discharge occurs. Therefore, compared with the case where the occurrence of the re-discharge is detected based on the primary voltage V1, it is possible to directly determine whether the re-discharge occurs based on the voltage between the electrodes of the spark plug 200, so that the detection accuracy can be improved. In addition, although the occurrence of the re-discharge can be detected based on the secondary current I2, if Figure 7 As shown, the change in the secondary current I2 due to the re-discharge of the spark plug 200 occurs instantaneously in a short time. Therefore, as described above, by detecting the re-discharge of the spark plug 200 based on the time differential dV2 / dt of the secondary voltage V2, more reliable detection can be performed.

[0156] When the time differential dV2 / dt of the secondary voltage V2 exceeds the threshold value, in step S104, the value of the secondary voltage V2 in a certain period before and after the exceeding time point is recorded and the maximum point is detected therefrom. Therefore, the timing immediately before the next discharge between the electrodes of the spark plug 200 can be detected.

[0157] In step S105, the generation time of the maximum point detected in step S104 is recorded as the maximum time.

[0158] In step S106, it is determined whether a predetermined number of measurement results have been obtained in the processing of steps S101 to S105 implemented so far. Here, it is determined whether a predetermined number of sample measurement results have been obtained from a statistical point of view, etc. If the above measurement results have been obtained, the processing proceeds to step S107. On the other hand, if the predetermined number of measurement results have not been obtained, the process returns to step S102 and the detection of the secondary voltage V2 continues.

[0159] In step S107, a distribution diagram of the maximum periods recorded in step S105 implemented so far is produced. Fig. 9 The scatter plot shown, Fig.10 The histogram shown is made as a distribution diagram of the maximum period.

[0160] In step S108, the interval between the rising period A and the falling period B of the ignition signal SB is set for the distribution map created in step S107. As described above, the interval between the rising period A and the falling period B on the distribution map is fixed to match the energization period of the auxiliary primary coil 360 that is allowable in terms of heat generation according to the rotation speed of the internal combustion engine 100.

[0161] In step S109, in the distribution map created in step S107, the rising period A and the falling period B having the largest total number of maximum period records within the fixed interval set in step S108 are determined.

[0162] In step S110 , the overlap energization start time is set based on the rising period A and the falling period B determined in step S109 .

[0163] If the overlap energization start time can be set through the above process, the process ends in step S111. Fig.13 The processing flow.

[0164] in addition, Fig.13 The processing is preferably 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 processing is performed for each measurement target value. Fig.13 In this way, the overlap energization start time can be set for each operating state of the internal combustion engine 100.

[0165] [Implementation 1: Discharge Control Flow of Sub-primary Coil]

[0166] Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 when the above-mentioned discharge control is performed will be described. Fig.14 is an example of a flowchart for explaining a method for controlling the secondary 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 controls the secondary primary coil 360 according to the first embodiment of the present invention. Fig.14 The flowchart starts the control of the secondary primary coil 360. In addition, Fig.14 The processing shown in the flowchart represents processing corresponding to one cycle of the internal combustion engine 100, and the phase control unit 380 performs the processing for each cycle. Fig.14 The process is shown in the flowchart.

[0167] In step S201, the phase control unit 380 starts Fig.14 The process is shown in the flowchart.

[0168] In step S202, the phase control unit 380 selects the overlapped energization start time. Here, the overlapped energization start time corresponding to the operating state of the internal combustion engine 100, such as the engine speed, is selected using predetermined mapping information or the like. The mapping information used here indicates the overlapped energization start time for each operating state of the internal combustion engine 100, and the overlapped energization start time is selected by the phase control unit 380. Fig.13 The processing is set in advance.

[0169] In step S203, the phase control unit 380 determines whether the ignition signal SA has changed from HIGH to LOW. As described above, the ignition control unit 83 starts outputting the ignition signal SA at a predetermined timing, and then stops outputting the ignition signal SA at a predetermined timing. Therefore, the main primary coil 310 starts supplying the electric energy E to the spark plug 200, and the discharge of the spark plug 200 starts. The phase control unit 380 can detect the discharge start timing of the spark plug 200 by detecting the falling period S of the ignition signal SA at this time in step S203.

[0170] In step S210 , the phase control unit 380 uses the falling period S of the ignition signal SA detected in step S203 as a starting point, and measures the elapsed time from that time point to the present.

[0171] In step S211, the phase control unit 380 compares the overlap energization start time selected in step S202 with the elapsed time measured in step S210 to determine whether the overlap energization start time has passed since the falling period S of the ignition signal SA. If the elapsed time is less than the overlap energization start time, it is determined that the overlap energization start time has not passed, and the process returns to step S210 to continue measuring the elapsed time. On the other hand, if the elapsed time is greater than the overlap energization start time, it is determined that the overlap energization start time has passed, and the process proceeds to step S220.

[0172] In step S220, the phase control unit 380 turns on the ignition signal SB and starts outputting the ignition signal SB. Therefore, at the rising period A of the ignition signal SB, the superimposed current starts to be supplied from the sub-primary coil 360 to the spark plug 200.

[0173] In step S221, the phase control unit 380 compares the elapsed time from the rising period A of the ignition signal SB determined by performing the processing of step S220 with the predetermined overlap power-on period. In addition, as described above, the overlap power-on period to be compared here is preset according to the power-on period of the auxiliary primary coil 360 that is allowable in terms of heat generation based on the rotation speed of the internal combustion engine 100. As a result, when the elapsed time is less than the overlap power-on period, it is determined that the overlap power-on period has not yet elapsed, and the determination in step S221 is continued. On the other hand, when the elapsed time is longer than the overlap power-on period, it is determined that the overlap power-on period has elapsed, and the process proceeds to step S222.

[0174] In step S222, the phase control unit 380 turns off the ignition signal SB and stops outputting the ignition signal SB. Therefore, the superimposed current supplied from the sub-primary coil 360 to the spark plug 200 is stopped during the falling period B of the ignition signal SB.

[0175] In step S223, the phase control unit 380 ends Fig.14 The process is shown in the flowchart.

[0176] According to the first embodiment of the present invention described above, the following effects are achieved.

[0177] (1) A control device 1 as an electronic control device controls the energization of an ignition coil 300 including a main primary coil 310 and a sub-primary coil 360 respectively arranged on the primary side and a secondary coil 320 arranged on the secondary side, thereby controlling the supply of electric energy from the ignition coil 300 to the spark plug 200 that discharges in the cylinder 150 of the internal combustion engine 100. The control device 1 controls the energization of the ignition coil 300 by a phase control unit 380 so that when a predetermined overlap energization start time has elapsed from the start of discharge of the main primary coil 310 (step S211: Yes), the energization of the sub-primary coil 360 is started (step S220), and when a predetermined overlap energization period corresponding to the rotation speed of the internal combustion engine 100 has elapsed from the start of energization of the sub-primary coil 360 (step S221: Yes), the energization of the sub-primary coil 360 is terminated (step S2222). Therefore, it is possible to suppress an increase in the volume and cost of the ignition coil 300 , while achieving both improvement in the fuel efficiency of the internal combustion engine 100 and suppression of ignition failure of the spark plug 200 .

[0178] (2) The overlap energization start time is determined based on the measurement result of the re-discharge time which represents 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, Fig.13 The overlapping energization start time is determined by the processing so that the number of times of re-discharge generation in the predetermined overlapping energization period is the largest in the distribution of the measurement results when the re-discharge time is measured multiple times (steps S109 and S110). Therefore, the energization start time of the auxiliary primary coil 360 can be appropriately determined so as to achieve both improvement of the fuel consumption of the internal combustion engine 100 and suppression of mis-ignition of the fuel by the spark plug 200.

[0179] (3) In the measurement of the re-discharge time, the occurrence of the re-discharge can be detected based on the differential value dV2 / dt of the secondary voltage when the voltage of the secondary coil 320 is measured as the secondary voltage V2. In this way, when the secondary voltage V2 drops sharply, it is determined that the re-discharge has occurred, and the occurrence of the re-discharge can be easily detected. Therefore, the re-discharge time can be accurately measured.

[0180] [Embodiment 2: Circuit of ignition coil]

[0181] Next, a circuit 400A including the ignition coil 300 according to the second embodiment of the present invention will be described.

[0182] Fig.15 4 is a diagram for explaining a circuit 400A including an ignition coil 300 according to a second embodiment of the present invention. In this embodiment, the ignition coil 300 has the same structure as that described in the first embodiment. Figure 8 That is, the ignition coil 300 of the present embodiment also includes two types of primary coils 310 and 360 (main primary coil 310 and sub-primary coil 360 ) wound with a predetermined number of turns, and a secondary coil 320 wound with a greater number of turns than the primary coils 310 and 360 .

[0183] In this embodiment, circuit 400A is different from circuit 400 described in Embodiment 1 in that voltage detection unit 370 is provided between secondary coil 320 and spark plug 200. Voltage detection unit 370 detects secondary voltage V2 and sends the value to ignition control unit 83.

[0184] In the present embodiment, the phase control unit 380 compares the secondary voltage V2 detected by the voltage detection unit 370 with a predetermined overlap voltage range. Similar to the overlap start time described in the first embodiment, the overlap voltage range is set based on the result of measuring the occurrence of re-discharge when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100 during the development stage of the ignition control unit 83. Specifically, for example, Fig. 9 In the scatter diagram of , the lower limit voltage C and the upper limit voltage D of the secondary voltage V2 are set as described above, and the voltage range between the lower limit voltage C and the upper limit voltage D is set as the overlapping energization voltage range.

[0185] In addition, when the occurrence of re-discharge is recorded by other methods, the overlapping energization voltage range can be set in the same manner. The lower limit voltage and the upper limit voltage of the overlapping energization voltage range can be set so that the number of re-discharges within the specified voltage range is the largest in the distribution of the measurement results of the re-discharge voltage recorded by any method, that is, the secondary voltage V2 at the time point immediately before the re-discharge occurs.

[0186] As a result of comparing the secondary voltage V2 with the overlap energization voltage range, when the secondary voltage V2 is within the overlap energization voltage range and the spark plug 200 is re-discharged, the phase control unit 380 outputs the ignition signal SB in the same manner as described in Embodiment 1. Therefore, the overlap current is supplied from the secondary primary coil 360 to the spark plug 200 to suppress the re-discharge (restrike: re-ignition) caused by the capacitor discharge in the spark plug 200. On the other hand, when the spark plug 200 is re-discharged when the secondary voltage V2 is outside the overlap energization voltage range, the phase control unit 380 does not output the ignition signal SB. Therefore, when the possibility of re-discharge in the spark plug 200 is low, the supply of the overlap current from the secondary primary coil 360 to the spark plug 200 is stopped to suppress power consumption.

[0187] [Implementation 2: Flow of Setting Overlap Energization Start Time and Overlap Energization Voltage Range]

[0188] Next, a method of setting the overlap energization start time and the overlap energization voltage range performed in advance in order to implement the above-mentioned discharge control will be described. Fig.16 FIG. 1 is an example of a flowchart for explaining a method for setting the overlap energization start time and the overlap energization voltage range according to Embodiment 2 of the present invention. Fig.16 In the flowchart of Fig.13 The steps of the common processing of the flowchart are assigned Fig.13 Same step number. Fig.13 The different points are centered on Fig.16 The processing shown in the flowchart is described.

[0189] In step S105A, the value and the generation time of the local maximum point detected in step S104 are recorded as the local maximum value and the local maximum time, respectively.

[0190] In step S107A, a distribution diagram of the maximum values ​​and maximum periods recorded in step S105A implemented so far is created. Fig. 9 The scatter diagram shown is made as a distribution diagram of the maximum value and the maximum period.

[0191] In step S108A, the interval between the rising period A and the falling period B of the ignition signal SB, and the interval between the lower limit voltage C and the upper limit voltage D are set for the distribution map created in step S107A. As described above, the interval between the rising period A and the falling period B on the distribution map is fixed to match the energization period of the auxiliary primary coil 360 that is allowable in terms of heat generation, and the interval between the lower limit voltage C and the upper limit voltage D is fixed based on predetermined conditions, such as a requested value of power consumption.

[0192] In step S109A, in the distribution map created in step S107A, rising period A and falling period B, as well as lower limit voltage C and upper limit voltage D having the largest total number of maximum period records within the fixed interval set in step S108A are determined.

[0193] In step S110A, the overlap energization start time is set based on the rising period A and the falling period B determined in step S109A. In addition, the overlap energization voltage range is set based on the lower limit voltage C and the upper limit voltage D determined in step S109A.

[0194] When the overlap energization start time and overlap energization voltage range can be set through the above process, the process ends in step S111. Fig.16 The processing flow.

[0195] in addition, Fig.16 The processing in Fig.13 Similarly, the processing is preferably performed in each operating state of the internal combustion engine 100. For example, a plurality of measurement target values ​​are set for the engine speed, and the processing is performed for each of the measurement target values. Fig.16 In this way, the overlap energization start time and the overlap energization voltage range can be set for each operating state of the internal combustion engine 100.

[0196] [Implementation 2: Discharge Control Flow of Sub-primary Coil]

[0197] Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 when the above-mentioned discharge control is performed will be described. Fig.17 is an example of a flowchart for explaining a method for controlling the secondary primary coil 360 by the phase control unit 380 according to the second embodiment of the present invention. Fig.17 In the flowchart of Fig.14 The steps of the common processing of the flowchart are assigned Fig.14 Same step number. Fig.14 The different points are centered on Fig.17 The processing shown in the flowchart is described.

[0198] In step S211, when the elapsed time from the falling period S of the ignition signal SA is equal to or longer than the overlap energization start time, it is determined that the overlap energization start time has elapsed, and the process proceeds to step S212.

[0199] In step S212 , the phase control section 380 acquires the value of the secondary voltage V2 detected by the voltage detection section 370 .

[0200] In step S213, the phase control unit 380 compares the secondary voltage V2 obtained in step S212 with the preset overlap voltage range to determine whether the secondary voltage V2 is within the overlap voltage range. Fig.16 The processing is preset and is set for each operating state of the internal combustion engine 100.

[0201] If it is determined in step S213 that the secondary voltage V2 is within the overlap voltage range, the process proceeds to step S220, and the phase control unit 380 turns on the ignition signal SB and starts outputting the ignition signal SB. Therefore, during the rising period A of the ignition signal SB, the overlap current starts to be supplied from the secondary primary coil 360 to the spark plug 200. On the other hand, if it is determined in step S213 that the secondary voltage V2 is outside the overlap voltage range, that is, greater than the upper limit voltage D or less than the lower limit voltage C, the phase control unit 380 proceeds to step S223 and ends. Fig.17 In this case, the superimposed current is not supplied from the secondary primary coil 360 to the spark plug 200.

[0202] According to the second embodiment of the present invention described above, in addition to (1) to (2) described in the first embodiment,

[0203] In addition to (3), the following effects are also achieved.

[0204] (4) When the voltage V2 of the secondary coil 320 at the time of the overlap energization start time after the discharge start of the main primary coil 310 is greater than the prescribed upper limit voltage D or less than the prescribed lower limit voltage C (step S213: No), the control device 1 does not energize the auxiliary primary coil 360 through the phase control unit 380. Therefore, when the possibility of re-discharge in the spark plug 200 is low, the supply of the overlap current from the auxiliary primary coil 360 to the spark plug 200 is stopped, so that the power consumption of the ignition coil 300 can be further suppressed.

[0205] (5) The upper limit voltage D and the lower limit voltage C are determined based on the measurement result of the re-discharge voltage, which represents the voltage V2 of the secondary coil 320 at the time point immediately before the re-discharge occurs when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100. Specifically, Fig.16In the distribution of each measurement result when the re-discharge voltage is measured multiple times, the upper limit voltage D and the lower limit voltage C are determined so that the number of times of re-discharge is maximized within the specified voltage range (steps S109A and S110A). Therefore, the range of the secondary voltage V2 energized to the auxiliary primary coil 360 can be appropriately set so that the spark plug 200 can suppress the ignition of the gas and the further power consumption of the ignition coil 300 can be suppressed.

[0206] [Embodiment 3: Circuit of ignition coil]

[0207] Next, a circuit 400B including the ignition coil 300 according to the third embodiment of the present invention will be described.

[0208] Fig.18 1 is a diagram for explaining a circuit 400B including an ignition coil 300 according to a third embodiment of the present invention. In this embodiment, the ignition coil 300 has the same structure as that described in the first embodiment. Figure 8 That is, the ignition coil 300 of the present embodiment also includes two types of primary coils 310 and 360 (main primary coil 310 and sub-primary coil 360 ) wound with a predetermined number of turns, and a secondary coil 320 wound with a greater number of turns than the primary coils 310 and 360 .

[0209] In the present embodiment, the circuit 400B is different from the circuit 400 described in the first embodiment in that the timer circuit 381 is provided separately from the ignition control unit 83, and the phase control unit 380 is provided in the timer circuit 381. The timer circuit 381 sets a timer value corresponding to the overlapped energization period, and when the ignition signal SB is output by the phase control unit 380 and the secondary primary coil 360 starts to be energized, the timer circuit 381 counts the elapsed time of the ignition signal SB from the rising period A. 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 function of the timer circuit 381 is used to control the on-period of the ignition signal SB.

[0210] In the present embodiment, the timer circuit 381 obtains the on-period (charging period of the main primary coil 310) or cycle (discharging period of the spark plug 200) of the ignition signal SA. Then, the timer value is set based on these values ​​obtained. For example, the value obtained by multiplying the on-period or cycle of the ignition signal SA by a predetermined multiplication factor is set as the timer value.

[0211] Fig.19 is an example of mapping information showing the relationship between the engine speed of the internal combustion engine 100 and the on-period of the ignition signal SA. Fig.19As shown, the on period of ignition signal SA changes according to the engine speed of internal combustion engine 100 .

[0212] Fig. 20 0 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. Fig. 20 As shown in the graph of , the shorter the on-period of the ignition signal SA is, the shorter the on-period of the ignition signal SB is set.

[0213] Timer circuit 381 uses Fig.19 The relationship between the engine speed and the on-time of the ignition signal SA shown is, for example, based on Fig. 20 The timer value is set according to the on-period of the ignition signal SB corresponding to the on-period of the acquired ignition signal SA. Therefore, the timer value that changes according to the engine speed can be set without using mapping information pre-set for each operating state of the internal combustion engine 100.

[0214] In addition, in the above description, an example is described in which the on-period of the ignition signal SA is changed according to the engine speed of the internal combustion engine 100, and the timer value of the timer circuit 381 is set based on the on-period of the ignition signal SA to control the on-period of the ignition signal SB. However, the cycle of the ignition signal SA, that is, the discharge cycle of the spark plug 200, can also be controlled in the same way. That is, the cycle of the ignition signal SA changes according to the engine speed of the internal combustion engine 100. Therefore, this point can also be used to set the timer value of the timer circuit 381 based on the cycle of the ignition signal SA to control the on-period of the ignition signal SB. Even so, it is possible to set the timer value that changes according to the engine speed without using the mapping information preset for each operating state of the internal combustion engine 100.

[0215] [Implementation 3: Discharge Control Flow of Sub-primary Coil]

[0216] Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 and the timer circuit 381 when the above-mentioned discharge control is implemented will be described. Fig.21 is an example of a flowchart for explaining a method for controlling the secondary primary coil 360 by the phase control unit 380 and the timer circuit 381 according to the third embodiment of the present invention. Fig.21 In the flowchart of Fig.14 The steps of the common processing of the flowchart are assigned Fig.14 Same step number. Fig.14 The different points are centered on Fig.21 The processing shown in the flowchart is described.

[0217] When starting in step S201 Fig.21 In the process shown in the flowchart of , phase control unit 380 selects the overlap energization start time in step S202. Here, using information preset in the same manner as in the first embodiment, the overlap energization start time corresponding to the operating state of internal combustion engine 100, such as the engine speed, is selected.

[0218] When it is determined in step S203 that the ignition signal SA changes from HIGH to LOW, in the next step S204, the timer circuit 381 obtains the on-period of the ignition signal SA. Here, for example, the on-period of the ignition signal SA is obtained by obtaining a predetermined monitoring signal output synchronously with the ignition signal SA from the ignition control unit 83.

[0219] In step S205, the timer circuit 381 sets a timer value based on the on-period of the ignition signal SA obtained in step S204. Here, for example, a value obtained by multiplying the on-period of the ignition signal SA by a predetermined multiplication factor is set as the timer value.

[0220] In addition, as described above, when the timer value of the timer circuit 381 is set based on the cycle of the ignition signal SA, in step S204, the cycle is obtained instead of the on-period of the ignition signal SA, and the processing of step S205 is implemented based on the cycle, thereby setting the timer value.

[0221] The timer value set in step S205 is used for the determination in step S221. That is, in this embodiment, in step S221, the timer circuit 381 compares the elapsed time counted from the time when the ignition signal SB is 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 overlap power-on period has not yet passed, and the determination in step S221 is continued. On the other hand, if the elapsed time reaches the timer value, it is determined that the overlap power-on period has passed, and the process proceeds to step S222.

[0222] According to the third embodiment of the present invention described above, in addition to (1) to (3) described in the first embodiment, the following effects are achieved.

[0223] (6) The control device 1 includes a timer circuit 381 that sets a timer value corresponding to the overlap energization period, and when the time elapsed after the start of energization of the auxiliary primary coil 360 reaches the timer value, the energization of the auxiliary primary coil 360 is terminated. Therefore, the energization control of the auxiliary primary coil 360 that reflects the operating state of the internal combustion engine 100 can be performed without using mapping information that is pre-set for each operating state of the internal combustion engine 100.

[0224] (7) The timer circuit 381 sets the timer value based on the charging cycle of the main primary coil 310 or the discharging cycle of the spark plug 200. Therefore, the timer value can be set so that the energization cycle of the sub-primary coil 360 is appropriately changed according to the engine speed.

[0225] [Implementation Method 4]

[0226] Next, a fourth embodiment of the present invention will be described. In this embodiment, an example of correcting the overlap energization start time corresponding to the gas flow rate between electrodes during the discharge process of the spark plug 200 using the circuit 400A described in the second embodiment will be described.

[0227] Fig. 22 FIG. 1 is a diagram showing an example of a timing diagram 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. Fig. 22 As shown in the timing diagram of , during the discharge period of the spark plug 200 after the falling period S of the ignition signal SA, the values ​​of the secondary voltage V2 at the periods T1 and T2 are respectively acquired. Then, based on the acquired values ​​of the secondary voltage V2, the slope of the curve graph representing the time variation of the secondary voltage V2 is obtained, and the overlap energization start time is adjusted based on the magnitude of the slope. For example, the overlap energization start time can be adjusted by taking the preset overlap energization start time as a reference value and adding a correction value corresponding to the time variation of the secondary voltage V2 thereto.

[0228] The secondary voltage V2 of the spark plug 200 during the discharge process changes according to the gas flow rate between the electrodes. Therefore, as described above, by finding the slope of the graph showing the time change of the secondary voltage V2 and changing the overlap energization start time according to the magnitude of the slope, the time interval from the falling period S of the ignition signal SA to the rising period A of the ignition signal SB can be adjusted according to the gas flow rate between the electrodes. Therefore, the overlap energization start time corresponding to the gas flow rate between the electrodes during the discharge process of the spark plug 200 can be calibrated.

[0229] Fig.23 1 is an example of a graph showing the relationship between the gas flow rate between the electrodes (temporal variation of the secondary voltage V2) and the correction added value for the rising period A of the ignition signal SB. Fig.23 As shown in the graph of , the gas flow rate between the electrodes becomes a high flow rate, and the time change of the secondary voltage V2 becomes larger accordingly, and the correction addition value relative to the rising period A is set smaller, thereby correcting to advance the rising period A of the ignition signal SB. As a result, the overlap energization start time can be shortened, and the energization period of the auxiliary primary coil 360 can be adjusted according to the gas flow rate.

[0230] [Implementation 4: Discharge Control Flow of Sub-primary Coil]

[0231] Next, a method of controlling the sub-primary coil 360 by the phase control unit 380 when the above-mentioned discharge control is performed will be described. Fig.24 is an example of a flowchart for explaining a method for controlling the secondary primary coil 360 by the phase control unit 380 according to the fourth embodiment of the present invention. Fig.24 In the flowchart of Fig.14 The steps of the common processing of the flowchart are assigned Fig.14 Same step number. Fig.14 The different points are centered on Fig.24 The processing shown in the flowchart is described.

[0232] When starting in step S201 Fig.24 In the process shown in the flowchart of , phase control unit 380 selects the overlap energization start time in step S202. Here, using information preset in the same manner as in the first embodiment, the overlap energization start time corresponding to the operating state of internal combustion engine 100, such as the engine speed, is selected.

[0233] When it is determined in step S203 that the ignition signal SA changes from HIGH to LOW, in the next step S206 , the phase control unit 380 acquires the value of the secondary voltage V2 detected by the voltage detection unit 370 .

[0234] In step S207, the phase control unit 380 estimates the gas flow rate between the electrodes of the spark plug 200 based on the secondary voltage V2 acquired in step S206. Here, as described above, the slope of the secondary voltage V2 is obtained based on the values ​​of the secondary voltage V2 acquired at the current time and in the period before the current time, and the gas flow rate between the electrodes is estimated based on the magnitude of the slope. In addition, only one value of the secondary voltage V2 is acquired, so if the slope of the secondary voltage V2 cannot be calculated, the processing of step S207 can be omitted.

[0235] In step S208, the phase control unit 380 corrects the overlap energization start time selected in step S202 based on the gas flow rate estimated in step S207. Fig.23 The correction added value is determined based on the relationship between the gas flow rate between the electrodes shown in FIG. 1 and the correction added value for the rising period A of the ignition signal SB, and the overlap energization start time is corrected by adding the correction added value. Therefore, the overlap energization start time is changed based on the time change of the secondary voltage V2 corresponding to the change in the gas flow rate.

[0236] The overlap 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 overlap energization start time corrected in step S208 with the elapsed time measured in step S210 to determine whether the overlap energization start time has passed since the falling period S of the ignition signal SA. As a result, if the elapsed time is less than the overlap energization start time, it is determined that the overlap energization start time has not passed, and the process returns to step S206, and the overlap energization start time and the elapsed time are continuously corrected based on the time change of the secondary voltage V2. On the other hand, if the elapsed time is greater than the overlap energization start time, it is determined that the overlap energization start time has passed, and the process proceeds to step S220.

[0237] According to the fourth embodiment of the present invention described above, in addition to (1) to (3) described in the first embodiment, the following effects are achieved.

[0238] (8) The control device 1 changes the overlapping 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). As a result, the energization period of the secondary primary coil 360 can be adjusted according to the gas flow rate between the electrodes in the spark plug 200. Therefore, even if the operating state of the internal combustion engine 100 changes with each combustion cycle, the spark plug 200 can reliably suppress the ignition of the gas. This is applicable not only to a series hybrid electric vehicle in which the internal combustion engine 100 drives the generator motor and uses its electricity to drive the drive motor, but also to a conventional vehicle or a parallel hybrid electric vehicle in which the vehicle is driven by the internal combustion engine 100.

[0239] [Modifications]

[0240] In the above-described embodiments 1 to 4, the control device 1 can make the discharge start timing of the main primary coil 310, i.e., the falling period S of the ignition signal SA, become earlier according to the operating state of the internal combustion engine 100 by the phase control unit 380, so as to extend the period from the falling period S of the ignition signal SA to the rising period A of the ignition signal SB and increase the overlap energization start time. Thus, when the spark plug 200 is discharged in the cylinder 150 of the internal combustion engine 100, the ignition signal SB can be output according to the timing of the collapse (tumble collapse) of the tumble flow in the gas in the cylinder 150, so as to supply the overlap current from the secondary primary coil 360 to the spark plug 200. Therefore, the blowout of the discharge path due to the tumble collapse can be effectively suppressed, and the ignitability of the spark plug 200 to the gas can be improved.

[0241] In addition, in each of the above-described embodiments, as described above, the software executed by the MPU 50 can be used to implement Figure 3 Each functional configuration of the control device 1 described in the above description may be realized by hardware such as FPGA (Field-Programmable Gate Array). In addition, these may be used in combination.

[0242] The first to fourth embodiments described above may be applied independently or in any combination of two or more. In addition, one of them may be selectively applied based on the operating conditions of the internal combustion engine 100 or the like.

[0243] Each embodiment and various modifications described above are only examples, and the present invention is not limited to these contents as long as the features of the present invention are not destroyed. In addition, although various embodiments and modifications are described above, the present invention is not limited to these contents. Other modes that can be considered within the scope of the technical concept of the present invention are also included in the scope of the present invention.

[0244] Description of symbols

[0245] 1. Control device

[0246] 10Analog input part

[0247] 20 Digital input unit

[0248] 30A / D conversion unit

[0249] 40RAM

[0250] 50MPU

[0251] 60ROM

[0252] 70 I / O ports

[0253] 80 output circuit

[0254] 81 Overall Control Department

[0255] 82 Fuel injection control unit

[0256] 83 Ignition control unit

[0257] 84 Cylinder identification unit

[0258] 85 Angle information generation unit

[0259] 86 Speed ​​information generation unit

[0260] 87 Intake air volume measurement unit

[0261] 88 Load information generation unit

[0262] 89 Water temperature measurement unit

[0263] 100 Internal Combustion Engine

[0264] 110 Air Purifier

[0265] 111 Intake pipe

[0266] 112 Intake manifold

[0267] 113 Throttle valve

[0268] 113a Throttle valve opening sensor

[0269] 114 Flow sensor

[0270] 115 Intake air temperature sensor

[0271] 120 Ring gear

[0272] 121 crank angle sensor,

[0273] 122 water temperature sensor

[0274] 123 Crankshaft

[0275] 125 Accelerator pedal

[0276] 126 Throttle position sensor

[0277] 130 fuel tank

[0278] 131 Fuel Pump

[0279] 132 Pressure Regulator

[0280] 133 fuel pipe

[0281] 134 Fuel injection valve

[0282] 140 Combustion pressure sensor

[0283] 150 cylinder

[0284] 151 Intake valve

[0285] 152 Exhaust valve

[0286] 160 exhaust manifold

[0287] 161 three-way catalyst

[0288] 162 Upstream air-fuel ratio sensor

[0289] 163 Downstream air-fuel ratio sensor

[0290] 170 piston

[0291] 200 spark plugs

[0292] 210 center electrode

[0293] 220 outer electrode

[0294] 230 Insulator

[0295] 300, 300C ignition coil

[0296] 310 Main primary coil

[0297] 320 secondary coil

[0298] 330 DC power supply

[0299] 340, 350 igniter

[0300] 360 primary coils

[0301] 370 voltage detection unit

[0302] 380 Phase Control Unit

[0303] 381 timer circuit

[0304] 390 resistor

[0305] 400, 400A, 400B, 400C electrical circuits.

Claims

1. An electronic control device, which controls the supply of electric energy from the ignition coil to a spark plug for discharging in a cylinder of an internal combustion engine by controlling the energization of the ignition coil, wherein the ignition coil includes a main primary coil and a sub-primary coil respectively arranged on the primary side, and a secondary coil arranged on the secondary side, wherein the electronic control device is characterized in that: The energization of the ignition coil is controlled so that the energization of the auxiliary primary coil is started when a prescribed overlap energization start time has passed after the discharge of the main primary coil is started, and the energization of the auxiliary primary coil is ended when a prescribed overlap energization period corresponding to the rotation speed of the internal combustion engine has passed after the start of the energization of the auxiliary primary coil. The overlap energization start time is determined based on a measurement result of a re-discharge time, wherein the re-discharge time indicates a time from the start of discharge to the re-discharge when the spark plug is discharged in a cylinder of the internal combustion engine. The overlap energization start time is determined so that the number of times the re-discharge occurs during the overlap energization period becomes the maximum in the distribution of the measurement results when the re-discharge time is measured a plurality of times.

2. The electronic control device according to claim 1, characterized in that In the measurement of the re-discharge time, the occurrence of the re-discharge is detected based on a differential value of the secondary voltage when the voltage of the secondary coil is measured as the secondary voltage.

3. The electronic control device according to claim 1 or 2, characterized in that: When the voltage of the secondary coil at the time when the overlap energization start time has elapsed after the discharge of the main primary coil is started is greater than a predetermined upper limit voltage or less than a predetermined lower limit voltage, the sub-primary coil is not energized.

4. The electronic control device according to claim 3, characterized in that: The upper limit voltage and the lower limit voltage are determined based on a measurement result of a re-discharge voltage indicating a voltage of the secondary coil at a point in time immediately before re-discharge occurs when the spark plug is discharged in a cylinder of the internal combustion engine.

5. The electronic control device according to claim 4, characterized in that: The upper limit voltage and the lower limit voltage are determined so that the number of times the re-discharge occurs becomes the maximum in a predetermined voltage range in distribution of each measurement result when the re-discharge voltage is measured a plurality of times.

6. The electronic control device according to claim 1, characterized in that: When the rotation speed of the internal combustion engine is 2400 revolutions per minute, the overlap power supply period is 0.5 milliseconds.

7. The electronic control device according to claim 1, characterized in that: A timer circuit is provided, the timer circuit setting a timer value corresponding to the overlap energization period, and terminating the energization of the sub-primary coil when the elapsed time after the start of energization of the sub-primary coil reaches the timer value.

8. The electronic control device according to claim 7, characterized in that: The timer circuit sets the timer value based on a charging period of the main primary coil or a discharge period of the spark plug.

9. The electronic control device according to claim 1, characterized in that: The overlap energization start time is changed based on a temporal change in the voltage of the secondary coil.

10. An electronic control device, which controls the supply of electric energy from the ignition coil to a spark plug for discharging in a cylinder of an internal combustion engine by controlling the energization of the ignition coil, the ignition coil comprising a main primary coil and a sub-primary coil respectively arranged on the primary side, and a secondary coil arranged on the secondary side, the electronic control device being characterized in that: The energization of the ignition coil is controlled so that the energization of the auxiliary primary coil is started when a predetermined overlap energization start time has passed after the discharge of the main primary coil is started, and the energization of the auxiliary primary coil is ended when a predetermined overlap energization period has passed after the energization of the auxiliary primary coil is started, The overlap energization start time is increased as the discharge start timing of the main primary coil becomes earlier in accordance with the operating state of the internal combustion engine.

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