Combustion engine control unit

Abstract

Internal combustion engine control device (1), comprising: an ignition control unit (83) which performs an ignition control for controlling a spark plug (200) which discharges current in a cylinder (150) of an internal combustion engine (100) to ignite fuel, wherein the ignition control unit (83) performs the ignition control such that a predetermined electrical ignition energy is supplied to the spark plug (200) when the spark plug (200) performs the ignition, and a predetermined electrical preheating energy smaller than the electrical ignition energy is supplied to the spark plug (200) before the spark plug (200) performs the ignition.

Description

Technical area

[0001] The present invention relates to an internal combustion engine control device. Current state of the art

[0002] For several years, there has been a need to improve the performance of exhaust catalysts (three-way catalysts) in internal combustion engines due to increasingly stringent emissions regulations. Expensive precious metals such as platinum are used for exhaust catalysts in internal combustion engines. However, as emissions regulations become increasingly stringent, many precious metals must be used to improve exhaust gas purification performance, and the manufacturing costs of exhaust catalysts are rising.

[0003] In this type of internal combustion engine, a large amount of hydrocarbons (HC) is generated, especially during a cold start, when the engine temperature is lower than the outside air temperature. Thus, by preventing the generation of hydrocarbons during a cold start, the amount of precious metal used in the exhaust catalyst can be reduced, thus lowering the manufacturing cost of the exhaust catalyst.

[0004] In internal combustion engines, to prevent misfiring (extinction) of the ignition device (spark plug) during cold start, control is performed to increase the fuel injection quantity at the time of cold start. This increases the amount of hydrocarbons generated during cold start, making it difficult to reduce the cost of the exhaust catalyst.

[0005] PTL 1 discloses an engine ignition device in which a temperature decrease of an ignition device is prevented when ignition of the ignition device occurs at a timing (exhaust timing) other than a normal ignition timing in a combustion cycle of the internal combustion engine.

[0006] Furthermore, PTL 2 discloses an ignition device for an internal combustion engine and a control device for a vehicle, which are configured to suppress the formation of hydrocarbons during a cold start of the engine by heating an electrode of a spark plug during the cold start. More specifically, the control device is designed to cause the spark plug to discharge electrically in a state in which no fuel is injected into a cylinder via a fuel injection valve during a first combustion process after the start of operation of the internal combustion engine.

[0007] Furthermore, PTL 3 also discloses an engine control device, particularly for preventing faulty ignition due to moisture adhering to a spark plug. PTL 3 proposes stopping the fuel supply to the combustion chamber for approximately one second after a start switch is pressed, so that only air enters the combustion chamber. Accordingly, the combustion chamber is ventilated, allowing the moisture adhering to the spark plug to evaporate. List of citationsPatent literature PTL 1: JP S62 - 20 677 A PTL 2: WO 2019 / 087 748 A1 PTL 3: JP H05 - 33 698 A Summary of the inventionTechnical problem

[0008] However, in the engine ignition device disclosed in PTL 1, the temperature decrease of the spark plug is prevented after the temperature of the spark plug of the internal combustion engine increases, and the temperature of the spark plug increases before the cold start of the internal combustion engine. Thus, the generation of hydrocarbons in the internal combustion engine cannot be prevented, especially at the time of a cold start, and reducing the manufacturing cost of the exhaust catalyst becomes difficult.

[0009] Therefore, the present invention has been developed in view of the foregoing problems, and an object thereof is to prevent the generation of hydrocarbons in the internal combustion engine and to reduce the manufacturing cost of the exhaust catalyst. Technical solution

[0010] An internal combustion engine control device according to one aspect of the present invention includes: an ignition control unit that performs ignition control for controlling a spark plug that discharges current in a cylinder of an internal combustion engine to ignite fuel. The ignition control unit performs ignition control such that a predetermined ignition electrical energy is supplied to the spark plug when the spark plug performs ignition, and a predetermined preheating electrical energy smaller than the ignition electrical energy is supplied to the spark plug before the spark plug performs ignition.

[0011] An internal combustion engine control device according to another aspect of the present invention includes: an ignition control unit that controls the energization of an ignition coil, supplies electrical energy to a spark plug, and discharges current in a cylinder of an internal combustion engine to ignite fuel. The ignition control unit controls the energization of the ignition coil so that the spark plug is supplied with electrical energy to heat the spark plug before the spark plug performs ignition.

[0012] An internal combustion engine control device according to another aspect of the present invention comprises: an ignition control unit that performs ignition control for controlling a spark plug that discharges current in a cylinder of an internal combustion engine to ignite fuel. The ignition control unit performs the ignition control such that electrical energy for causing the spark plug to discharge current is supplied to the spark plug during a period including at least one exhaust stroke in which fuel is exhausted from the cylinder after combustion. Advantageous effects of the invention

[0013] According to the present invention, the generation of hydrocarbons in the internal combustion engine can be prevented and the manufacturing cost of the exhaust gas catalyst can be reduced. Short description of the drawings [ Fig. 1] Fig. 1 is a diagram showing a main configuration of an internal combustion engine and an internal combustion engine control device according to an embodiment. [ Fig. 2] Fig. 2 shows a partially enlarged view showing a spark plug. [ Fig. 3] Fig. 3 shows a functional block diagram for illustrating a functional configuration of a control device. [ Fig. 4] Fig. 4 is a diagram showing an electrical circuit including an ignition coil. [ Fig. 5] Fig. 5 is a diagram showing the relationship between an electrode temperature, a dielectric breakdown voltage, and an air-fuel ratio. [ Fig. 6] Fig. 6 shows an example of a timing chart for illustrating an output timing of an ignition signal according to a first embodiment. [ Fig. 7] Fig. 7 shows an example of a flowchart for illustrating a method of controlling a spark plug by an ignition control unit according to the first embodiment. [ Fig. 8] Fig. 8 is a diagram showing a time change of the electrode temperature of the spark plug according to a pre-ignition signal. [ Fig. 9] Fig. 9 shows an example of a timing chart showing an output timing of an ignition signal according to a second embodiment. [ Fig. 10] Fig. 10 shows an example of a flowchart for illustrating a method of controlling a spark plug by an ignition control unit according to the second embodiment. Description of embodiments- First embodiment -

[0014] An internal combustion engine control apparatus according to a first embodiment of the present invention will be described below.

[0015] The following describes a control device 1, which is one form of the internal combustion engine control device according to the first embodiment. In this embodiment, a case is described as an example in which the control device 1 controls the discharge (ignition) of a spark plug 200 arranged in each cylinder 150 of a four-cylinder internal combustion engine 100.

[0016] Hereinafter, in the embodiment, a combination of a partial or entire configuration of the internal combustion engine 100 or a partial or entire configuration of the control device 1 refers to the control device 1 of the internal combustion engine 100. [Internal combustion engine]

[0017] Fig. 1 is a diagram showing a main configuration of the internal combustion engine 100 and the internal combustion engine ignition device.

[0018] Fig. 2 shows a partially enlarged view showing electrodes 210 and 220 of the spark plug 200.

[0019] In the internal combustion engine 100, the air drawn in from the outside flows through an air cleaner 110, an intake pipe 111, and an intake manifold 112, and flows into each cylinder 150 when an intake valve 151 opens. The amount of air flowing into each cylinder 150 is controlled by a throttle valve 113, and the amount of air controlled by the throttle valve 113 is measured by a flow sensor 114.

[0020] The throttle valve 113 is equipped with a throttle opening sensor 113a that detects the opening of a throttle. The opening information of the throttle valve 113 detected by the throttle opening sensor 113a is output to the control device (electronic control unit) 1.

[0021] An electronic throttle valve driven by an electric motor is used as the throttle valve 113; however, the throttle valve may be of any design as long as the air flow rate can be adjusted accordingly.

[0022] The temperature of the gas flowing into each cylinder 150 is detected by an intake air temperature sensor 115.

[0023] A crank angle sensor 121 is arranged outside a ring gear 120 fixed to a crankshaft 123 in a radial direction. The crank angle sensor 121 detects the rotation angle of the crankshaft 123. In the embodiment, the crank angle sensor 121 detects the rotation angle of the crankshaft 123, for example, every 10° and every combustion cycle.

[0024] A water temperature sensor 122 is arranged on a water jacket (not shown) of a cylinder head. The water temperature sensor 122 detects the temperature of the cooling water of the internal combustion engine 100.

[0025] A vehicle is equipped with an accelerator position sensor 126 that detects the amount of movement (depression) of an accelerator pedal 125. The accelerator position sensor 126 detects the torque requested by a driver. The torque requested by the driver and detected by the accelerator position sensor 126 is output to the control device 1 described below. The control device 1 controls the throttle valve 113 based on this requested torque.

[0026] The fuel stored in a fuel tank 130 is sucked in and pressurized by a fuel pump 131, then flows through a fuel line 133 equipped with a pressure regulator 132, and is supplied to a fuel injection valve (injector) 134. The fuel discharged from the fuel pump 131 is regulated to a predetermined pressure by the pressure regulator 132 and injected into each cylinder 150 by the fuel injection valve (injector) 134. Due to the pressure regulation by the pressure regulator 132, excess fuel is returned to the fuel tank 130 via a return line (not shown).

[0027] The cylinder head (not shown) of the internal combustion engine 100 is equipped with a combustion pressure sensor (also referred to as a cylinder pressure sensor) 140. The combustion pressure sensor 140 is arranged in each cylinder 150 and detects the internal pressure (combustion pressure) of the cylinder 150.

[0028] A piezoelectric sensor or overpressure sensor is used as the combustion pressure sensor 140, and the internal combustion pressure (in-cylinder pressure) of the cylinder 150 can be detected over a wide temperature range.

[0029] An exhaust valve 152 and an exhaust manifold 160 for discharging the gas (exhaust gases) after combustion to the outside of the cylinder 150 are attached to each cylinder 150. A three-way catalyst 161 is arranged on the exhaust side of the exhaust manifold 160.

[0030] When the exhaust valve 152 is opened, exhaust gases are discharged from the cylinder 150 to the exhaust manifold 160. The exhaust gases are purified by the three-way catalyst 161 as they flow through the exhaust manifold 160 and are then released into the atmosphere.

[0031] An upstream air-fuel ratio sensor 162 is disposed 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 gases exiting each cylinder 150.

[0032] A downstream air-fuel ratio sensor 163 is arranged 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 mixture. In the embodiment, the downstream air-fuel ratio sensor 163 is, for example, an O2 sensor.

[0033] Furthermore, a spark plug 200 is arranged above each cylinder 150. Due to the discharge (ignition) of the spark plug 200, a spark is ignited in the air-fuel mixture of air and fuel in cylinder 150, an explosion occurs in cylinder 150, and a piston 170 is pushed downward. As the piston 170 is pushed downward, a crankshaft 123 rotates.

[0034] An ignition coil 300, which generates electrical energy (voltage) supplied to the spark plug 200, is connected to the spark plug 200. The voltage generated in the ignition coil 300 creates a discharge between a center electrode 210 and an outer electrode 220 of the spark plug 200 (see Fig. 2).

[0035] As in Fig. As shown in Figure 2, in the spark plug 200, the center electrode 210 is supported in an insulated state by an insulator 230. A predetermined voltage (for example, 20,000 V to 40,000 V in the embodiment) is applied to this center electrode 210.

[0036] The outer electrode 220 is grounded. When a predetermined voltage is applied to the center electrode 210, a discharge (ignition) occurs between the center electrode 210 and the outer electrode 220.

[0037] In the spark plug 200, dielectric breakdown of the gas component occurs due to the state of the gas between the center electrode 210 and the outer electrode 220 or the pressure in the cylinder, and the voltage at which the discharge (ignition) occurs changes. The voltage at which the discharge occurs is called the dielectric breakdown voltage.

[0038] The discharge control (ignition control) at the spark plug 200 is carried out by an ignition control unit 83 of the control device 1 as described below.

[0039] Out of Fig. 1, signals output from various sensors such as the throttle opening sensor 113a, the flow rate sensor 114, the crank angle sensor 121, the accelerator position sensor 126, the water temperature sensor 122, and the combustion pressure sensor 140, as described above, are output to the control device 1. The control device 1 detects the operating state of the internal combustion engine 100 based on the signals output from these various sensors and controls the amount of air flowing into the cylinder 150, the fuel injection amount, the ignition timing of the spark plug 200, and the like. [Hardware configuration of the control device]

[0040] The overall hardware configuration of the control device 1 is described below.

[0041] As in Fig. As shown in Figure 1, the control device 1 comprises an analog input unit 10, a digital input unit 20, an analog / digital (A / D) converter 30, a random access memory (RAM) 40, a micro-processing unit (MPU) 50, a read-only memory (ROM) 60, an input / output (I / O) port 70, and an output circuit 80.

[0042] Analog output signals from various sensors such as the throttle opening sensor 113a, the flow rate sensor 114, the accelerator position sensor 126, the upstream air-fuel ratio sensor 162, the downstream air-fuel ratio sensor 163, the combustion pressure sensor 140, and the water temperature sensor 122 are input to the analog input unit 10.

[0043] 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 subjected to signal processing such as denoising and converted into digital signals by the A / D converter 30 and stored in the RAM 40.

[0044] The digital output signal from the crank angle sensor 121 is output to the digital input unit 20.

[0045] The I / O port 70 is connected to the digital input unit 20, and the digital output signal input to the digital input unit 20 is stored in the RAM 40 via the I / O port 70.

[0046] Each output signal stored in RAM 40 is arithmetically processed by MPU 50.

[0047] The MPU 50 executes a control program (not shown) stored in the ROM 60 to arithmetically process the output signal stored in the RAM 40 according to the control program. The MPU 50 calculates a control value that defines the actuation amount of each actuator (for example, the throttle valve 113, the pressure regulator 132, and the spark plug 200) that drives the internal combustion engine 100 according to the control program and temporarily stores the control value in the RAM 40.

[0048] The control value stored in the RAM 40 and defining the actuation amount of the actuator is output to the output circuit 80 via the I / O port 70.

[0049] The output circuit 80 is connected to the function of the ignition control unit 83 (see Fig. 3) which controls a voltage applied to the spark plug 200 or the like. [Functional block of the control device]

[0050] The functional configuration of the control device 1 is described below.

[0051] Fig. 3 is a functional block diagram showing the functional configuration of the control device 1. Each function of the control device 1 is executed by the output circuit 80, for example, when the MPU 50 executes the control program stored in the ROM 60.

[0052] As in Fig. 3, the output circuit 80 of the control device 1 comprises an overall control unit 81, a fuel injection control unit 82 and an ignition control unit 83.

[0053] The overall control unit 81 is connected to an accelerator pedal position sensor 126 and a combustion pressure sensor 140 and receives the requested torque (acceleration signal S1) from the accelerator pedal position sensor 126 and an output signal S2 from the combustion pressure sensor 140.

[0054] The overall control unit 81 performs the overall control on the fuel injection control unit 82 and the ignition control unit 83 based on the requested torque (acceleration signal S1) from the accelerator pedal position sensor 126 and the output signal S2 from the combustion pressure sensor 140.

[0055] The fuel injection control unit 82 is connected to a cylinder determination unit 84 that determines each cylinder 150 of the internal combustion engine 100, an angle information generation unit 85 that measures the crank angle of the crankshaft 123, and a speed information generation unit 86 that measures an engine speed, and receives cylinder discrimination information S3 from the cylinder determination unit 84, crank angle information S4 from the angle information generation unit 85, and engine speed information S5 from the speed information generation unit 86.

[0056] The fuel injection control unit 82 is connected to an intake amount measuring unit 87 that measures the amount of intake air sucked into the cylinder 150, a load information generating unit 88 that measures an engine load, and a water temperature measuring unit 89 that measures the temperature of 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 information S8 from the water temperature measuring unit 89.

[0057] The fuel injection control unit 82 calculates the injection amount and injection timing (fuel injection valve control information S9) of fuel injected from the fuel injection valve 134 based on the received information, and controls the fuel injection valve 134 based on the calculated amount and injection timing of fuel.

[0058] The ignition control unit 83 is connected to the cylinder determination unit 84, the angle information generation unit 85, the rotational 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 each information from these units.

[0059] The ignition control unit 83 calculates the amount (excitation angle) of current for exciting a primary coil (not shown) of the ignition coil 300, an excitation start timing, and the timing for turning off the current (ignition timing) for exciting the primary coil based on the received information.

[0060] The ignition control unit 83 controls the discharge with the spark plug 200 (ignition control) by outputting an ignition signal SA to a primary coil 310 of the ignition coil 300 based on the calculated excitation angle, the excitation start timing and the ignition timing.

[0061] At least the function of the ignition control unit 83 for controlling the ignition of the spark plug 200 using the ignition signal SA corresponds to the internal combustion engine control device of the present invention. [Electrical circuit of the ignition coil)

[0062] An electrical circuit 400 comprising the ignition coil 300 is described below.

[0063] Fig. 4 is a diagram illustrating the electrical circuit 400 including the ignition coil 300. In the electrical circuit 400, the ignition coil 300 includes the primary coil 310 wound with a predetermined number of turns and a secondary coil 320 wound with more turns than the primary coil 310.

[0064] One end of the primary coil 310 is connected to a DC power supply 330. Accordingly, a predetermined voltage (for example, 12 V in the embodiment) is applied to the primary coil 310. A charge quantity detection unit 350 is arranged in the connection path between the DC power supply 330 and the primary coil 310. The charge quantity detection unit 350 detects the voltage and current applied to the primary coil 310 and sends the detected voltage and current to the ignition control unit 83.

[0065] The other end of the primary coil 310 is connected to an ignition electrode 340 and is grounded via the ignition electrode 340. A transistor, a field-effect transistor (FET), or the like is used for the ignition electrode 340.

[0066] The base (B) terminal of the ignition electrode 340 is connected to the ignition control unit 83. An ignition signal SA output from the ignition control unit 83 is input to the base (B) terminal of the ignition electrode 340. When the ignition signal SA is input to the base (B) terminal of the ignition electrode 340, the collector (C) terminal and the emitter (E) terminal of the ignition electrode 340 are energized, and current flows between the collector (C) terminal and the emitter (E) terminal. Accordingly, the ignition signal SA is output from the ignition control unit 83 to the primary coil 310 of the ignition coil 300 via the ignition electrode 340, and current (electrical energy) is collected in the primary coil 310.

[0067] When the output of the ignition signal Sa from the ignition control unit 83 is stopped and the current flowing through the primary coil 310 is cut off, a high voltage corresponding to the coil turns ratio of the coil with respect to the primary coil 310 is generated in the secondary coil 320. When the high voltage generated in the secondary coil 320 is applied to the spark plug 200 (center electrode 210), a potential difference is generated between the center electrode 210 of the spark plug 200 and the outer electrode 220. When the potential difference generated between the center electrode 210 and the outer electrode 220 is equal to or greater than the dielectric breakdown voltage Vm of the gas (air-fuel mixture in the cylinder 150), the dielectric breakdown of the gas component causes the discharge to occur between the center electrode 210 and the outer electrode 220, and the fuel (air-fuel mixture) is ignited.

[0068] A discharge amount detection unit 360 is arranged in the connection path between the secondary coil 320 and the spark plug 200. The discharge amount detection unit 360 detects a discharge voltage and a current and sends the detected discharge voltage and current to the ignition control unit 83.

[0069] By operating the electrical circuit 400 as described above, the ignition control unit 83 controls the excitation of the ignition coil 300 using the ignition signal SA. Accordingly, the ignition control for controlling the spark plug 200 is performed. [Relationship between spark plug temperature and air-fuel ratio]

[0070] The relationship between the temperature of the spark plug 200 and the air-fuel ratio is described below. At the time of cold start of the internal combustion engine 100, as the temperature of the electrode of the spark plug 200 decreases, the air-fuel ratio required for ignition must be reduced (mixture enrichment).

[0071] Fig. Figure 5 shows a graph illustrating the relationship between the electrode temperature, the dielectric breakdown voltage, and the air-fuel ratio. As shown in Fig. As shown in Figure 5, in the internal combustion engine 100, when the air-fuel ratio is increased (mixture leaning), the ignition of the air-fuel mixture by discharge (ignition) is made more difficult and thus the dielectric breakdown voltage for igniting the air-fuel mixture must be increased.

[0072] When the dielectric breakdown voltage is constant (the output current of the ignition coil 300 is constant) and the temperature of the electrode of the spark plug 200 decreases, the breakdown voltage is rarely exceeded unless the air-fuel ratio is reduced (air-fuel enrichment). Thus, in the internal combustion engine 100, the amount of hydrocarbons (HC) generated during combustion increases as the proportion of fuel in the air-fuel mixture increases.

[0073] This means that when the temperature of the spark plug electrode 200 increases at the time of cold start (see thick arrow in Fig. 5), the dielectric breakdown voltage may be exceeded even though the air-fuel ratio increases (leaning of the mixture), and the generation of hydrocarbons at the time of combustion may be reduced. Thus, in the internal combustion engine 100, when the temperature of the electrode of the spark plug 200 increases at the time of cold start before discharge (ignition), the generation of hydrocarbons (HC) can be prevented by increasing the air-fuel ratio at the time of cold start.

[0074] In Fig. In the example shown in Figure 5, when the electrode temperature of the spark plug 200 is low, the air-fuel ratio for ignition is at a predetermined dielectric breakdown voltage P1, and when the electrode temperature is high, the air-fuel ratio for ignition is at the predetermined dielectric breakdown voltage P2. Therefore, as the electrode temperature increases, the fuel required for ignition can be reduced, and the hydrocarbons (HC) generated by combustion are reduced. [Ignition signal output time]

[0075] Next, the output timing of the ignition signal SA will be described with respect to the method of heating the electrodes of the spark plug 200 according to the first embodiment.

[0076] Fig. 6 shows an example of a timing chart showing an output timing of an ignition signal SA according to the first embodiment.

[0077] In Fig. 6 represents the top row ON / OFF of the vehicle's ignition switch (not shown). When the vehicle's driver inserts a key (not shown) into an ignition switch (not shown) and turns the key (or presses a start button in a keyless device), the ignition switch is turned on.

[0078] The third phase from the top shows the output signal of the crank angle sensor 121. After the ignition switch is turned on, a cell motor switch is turned on, and when the crank angle sensor 121 starts detecting the rotation of the crankshaft 123 with the start of movement of the internal combustion engine 100, the output of the crank angle sensor 121 is turned on.

[0079] The fourth phase from the top represents the ignition signal SA output from the ignition control unit 83 to the ignition coil 300. The ignition signal SA includes a pre-ignition signal Sp and a main ignition signal Sa output after the pre-ignition signal Sp. The pre-ignition signal Sp is an ignition signal for supplying pre-heating electrical energy to the ignition coil 200 to increase the temperature of the spark plug 200 before the spark plug 200 ignites the fuel (air-fuel mixture) at the time of a cold start of the internal combustion engine 100. At the time of a cold start, the pre-ignition signal Sp is output from the ignition control unit 83 to the ignition coil 300 so that the temperature of the electrode of the spark plug 200 before discharge (ignition) is as previously described in Fig. 5 can be increased. This can prevent the generation of hydrocarbons (HC).

[0080] The main ignition signal Sa, in turn, is an ignition signal for the spark plug 200 for igniting the air-fuel mixture in the combustion stroke of the internal combustion engine 100. The output timing of the main ignition signal Sa is determined by the ignition control unit 83 as previously described in Fig. 3 described.

[0081] In the first embodiment, the ignition control unit 83 outputs the main ignition signal Sa for causing the spark plug 200 to discharge current (ignition) to the ignition coil 300 from time T4 to time T5 in the combustion stroke in the combustion cycle. Furthermore, in the stroke before the combustion stroke in a combustion cycle, that is, the stroke before the spark plug 200 ignites the fuel, the pre-ignition signal Sp for heating the spark plug 200 is output to the ignition coil 300. Hereinafter, the heating of the spark plug 200 by the pre-ignition signal Sp is also referred to as preheating.

[0082] As in Fig. As shown in Fig. 6, the pre-ignition signal Sp is repeatedly output a plurality of times after time T1 when the ignition switch is turned on, before time T2 when the signal output from the crank angle sensor 121 starts, and before time T4 when the output of the main ignition signal Sa starts. That is, the pre-ignition signal Sp is output a plurality of times before the first explosion in each cylinder 150. Here, the first explosion means the first combustion (explosion) in the first combustion stroke of each cylinder 150 after the operation of the internal combustion engine 100 is started. That is, in the internal combustion engine 100, the first explosion in each cylinder 150 occurs only once after the operation is started. Thereafter, a predetermined combustion cycle (intake stroke → compression stroke → combustion stroke → exhaust stroke) is repeated. However, the pre-ignition signal Sp can only be output once.

[0083] As in Fig. As shown in Figure 6, during the period from time T1 to time T4, a pulse signal is continuously output as the pre-ignition signal Sp at a predetermined duty cycle. The pulse width of the pre-ignition signal Sp is smaller than the pulse width of the main ignition signal Sa. Accordingly, the pre-ignition signal Sp is a signal for reducing the voltage change in the ignition coil 300 compared to that of the main ignition signal Sa for combustion (ignition of the air-fuel mixture).

[0084] As in Fig. As shown in Fig. 6, the cycle of the pulse signal output as the pre-ignition signal Sp is changed before and after time T3 when fuel injection is performed from the fuel injection valve 134. Specifically, after time T3, when fuel injection is performed from the fuel injection valve 134, the cycle of the pulse signal is set according to the pulse width of the pre-ignition signal Sp so that the voltage generated in the ignition coil 300 is lower than the dielectric breakdown voltage. Accordingly, after the fuel injection is performed, the pre-ignition electric energy supplied from the ignition coil 300 to the spark plug 200 becomes smaller than that before the fuel injection. Before time T3, when fuel injection is performed from the fuel injection valve 134, the air-fuel mixture is not ignited.Thus, the voltage generated in the ignition coil 300 according to the pre-ignition signal Sp may be greater than or equal to the dielectric breakdown voltage, or it may be less than the dielectric breakdown voltage. Furthermore, the pulse width of the pre-ignition signal Sp may be greater than the main ignition signal Sa.

[0085] As described above, in the first embodiment, the ignition control unit 83 outputs the pre-ignition signal Sp a plurality of times before outputting the main ignition signal Sa. Accordingly, before the spark plug 200 ignites the air-fuel mixture (fuel), the ignition control unit 83 controls the energization of the coil 300 so that the ignition coil 300 supplies the spark plug 200 with electrical energy to heat the spark plug 200. At this time, the ignition control unit 83 outputs the pulse signal of the pre-ignition signal Sp with a pulse width smaller than the pulse signal of the main ignition signal Sa. Accordingly, before the spark plug 200 ignites the air-fuel mixture (fuel), the ignition control of the spark plug 200 is performed so that a predetermined pre-ignition electrical energy smaller than the ignition electrical energy is supplied to the spark plug 200.When a high voltage is applied from the ignition coil 300 to the spark plug 200 based on the pre-ignition signal Sp at the time of cold start of the internal combustion engine 100, the spark plug 200 (the center electrode 210 and the outer electrode 220) is heated before the first explosion. As a result, as described above, even if the air-fuel ratio is increased (the fuel is reduced) at the time of discharge (ignition) of the ignition coil 300 in the combustion stroke, the generation of hydrocarbons (HC) due to combustion at the time of cold start can be prevented.

[0086] The fifth phase from the top shows the ON / OFF of the fuel injector 134. When the fuel injector 134 is actuated, a predetermined amount of fuel is injected through the fuel injector 134 into the cylinder 150 (the combustion chamber).

[0087] The lower row shows the in-cylinder pressure in cylinder 150 (in the combustion chamber). The in-cylinder pressure is measured by the combustion pressure sensor 140, and the measurement result of the combustion pressure sensor 140 is output. As described above, in the internal combustion engine 100, after the predetermined amount of fuel is injected by the fuel injection valve 134 to generate the air-fuel mixture in the combustion chamber, the air-fuel mixture is ignited at the time (time T5) when the main ignition signal Sa is turned off, and combustion occurs. Accordingly, the pressure in the cylinder 150 rises rapidly. The combustion pressure sensor 140 measures the in-cylinder pressure during the combustion cycle. [Spark plug control method]

[0088] An example of a control method of the spark plug 200 by the ignition control unit 83 is described below. Fig. 7 shows an example of a flowchart for illustrating a method of controlling the spark plug 200 by the ignition control unit 83 according to the first embodiment.

[0089] As in Fig. As shown in Figure 7, in step S101, the ignition control unit 83 determines whether the ignition switch is turned on or not. Thus, if it is determined that the ignition switch is turned on (step S101: YES), the process proceeds to step S102, and if it is determined that the switch is not turned on, that is, if it is determined that it is turned off (step S101: NO), the process returns to step S101.

[0090] In step S102, the ignition control unit 83 determines whether or not the cylinder 150 is after the first explosion. If the main ignition signal Sa is turned on once, it is determined that the cylinder is after the first explosion (step S102: YES), and the process ends in this state. On the other hand, if the main ignition signal Sa is not turned on once after the ignition switch is turned on, it is determined that the cylinder is before the first explosion (step S102: NO), and the process proceeds to step S103.

[0091] In step S103, the ignition control unit 83 determines whether or not fuel is being injected into the cylinder 150. If the fuel injection valve 134 itself is turned on once, it is determined that fuel is being injected (step S103: YES), and the process proceeds to step S105. On the other hand, if the fuel injection valve 134 itself is not turned on once after the ignition switch is turned on, it is determined that fuel injection is not occurring (step S103: NO), and the process proceeds to step S104.

[0092] In step S104, the ignition control unit 83 sets the output cycle of the pre-ignition signal Sp to be long. After step S104 is executed, the ignition control unit 83 proceeds to step S106 and, in step S106, outputs the pre-ignition signal Sp with the output cycle set in step S104. Accordingly, discharge control (ignition control) is performed on the spark plug 200 so that the voltage generated in the ignition coil 300 becomes equal to or greater than the dielectric breakdown voltage, and the spark plug 200 discharges current by the pre-ignition electric energy supplied from the ignition coil 300 to the spark plug 200 to generate a spark.

[0093] In step S105, the ignition control unit 83 sets the output cycle of the pre-ignition signal Sp to be short. After step S105 is executed, the ignition control unit 83 proceeds to step S106 and, in step S106, outputs the pre-ignition signal Sp with the output cycle set in step S105. Accordingly, discharge control (ignition control) is performed on the spark plug 200 so that the voltage generated in the ignition coil 300 becomes lower than the dielectric breakdown voltage, and no spark is generated, and the spark plug 200 does not discharge current by the pre-ignition electric energy supplied from the ignition coil 300 to the spark plug 200.

[0094] After the pre-ignition signal Sp is output in step S106, the process returns to step S101. Accordingly, the discharge control (ignition control) on the spark plug 200 is performed such that the output cycle of the pre-ignition signal Sp is changed before and after fuel injection, and the output of the pre-ignition signal Sp is stopped after the first explosion.

[0095] As described above, the first embodiment includes the spark plug 200 disposed in the cylinder 150 and the ignition control unit 83 that controls the discharge of the spark plug 200. In the first combustion cycle after the start of operation of the internal combustion engine 100, the ignition control unit 83 is configured to supply preheating electric power from the ignition coil 300 to the spark plug 200 until the output of the main ignition signal Sa is started after the ignition switch is turned on. With this configuration, preheating of the spark plug 200 can be performed before the first explosion of each cylinder 150 in the internal combustion engine 100, and thus the generation of hydrocarbons (HC) at the time of a cold start can be prevented.

[0096] In the first embodiment, the ignition control unit 83 is configured to supply preheating electrical energy from the ignition coil 300 to the spark plug 200 a plurality of times in the first combustion cycle after the start of operation of the internal combustion engine 100. With this configuration, the preheating of the spark plug 200 can be reliably performed, so that the generation of hydrocarbons (HC) at the time of a cold start can be reliably prevented.

[0097] Fig. Fig. 8 is a diagram showing the time change of the electrode temperature of the spark plug 200 according to the pre-ignition signal SP. In Fig. In the example shown in Fig. 8, when dielectric breakdown occurs, the temperature of the electrode increases more rapidly than when no dielectric breakdown occurs. Therefore, in the period where no effect occurs, although discharge occurs due to dielectric breakdown, that is, the period before the fuel injection valve 134 is turned on, it is desirable to output the pre-ignition signal Sp so that dielectric breakdown occurs between the center electrode 210 and the outer electrode 220 of the spark plug 200 due to the electric energy supplied from the ignition coil 300 to the spark plug 200. On the other hand, if discharge occurs in the spark plug 200 after fuel injection, misfire during the compression stroke will result. Thus, dielectric breakdown during preheating at this time must be prevented.Therefore, in the period after the fuel injection valve 134 is turned on, the pre-ignition signal Sp is desirably outputted, so that the output cycle of the pre-ignition signal Sp is changed to be shorter (the pulse width is reduced) in order to prevent dielectric breakdown between the center electrode 210 and the outer electrode 220 of the spark plug 200 due to the electric energy supplied from the ignition coil 300 to the spark plug 200.

[0098] According to the first embodiment of the present invention described above, the following operational effects are achieved.

[0099] (1) The internal combustion engine control device 1 includes the ignition control unit 83, which performs ignition control for controlling the spark plug 200, which discharges current into the cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit 83 performs ignition control such that a predetermined ignition electrical energy is supplied to the spark plug 200 when the spark plug 200 performs ignition, and a predetermined preheating electrical energy smaller than the ignition electrical energy is supplied to the spark plug 200 before the spark plug 200 performs ignition. Thus, the generation of hydrocarbons at the time of a cold start of the internal combustion engine 100 can be prevented, and the manufacturing cost of the exhaust catalyst can be reduced.

[0100] (2) The ignition control unit 83 performs ignition control such that preheating electric power is supplied to the spark plug 200 before the fuel injection valve 134 attached to the engine 100 injects fuel (between time T1 and time T3). Thus, preheating of the spark plug 200 can be performed at a timing suitable for preventing the generation of hydrocarbons at the time of a cold start of the engine 100.

[0101] (3) The ignition control unit 83 performs ignition control such that preheating electric power is supplied to the spark plug 200 between a time when the fuel injection valve 134 attached to the internal combustion engine 100 injects fuel and a time when ignition electric power is supplied to the spark plug 200 (between time T3 and time T4). Thus, preheating of the spark plug 200 can be performed at a time suitable for preventing the generation of hydrocarbons at the time of a cold start of the internal combustion engine 100.

[0102] (4) The ignition control unit 83 performs ignition control such that a first electric power is supplied as the preheating electric power to the spark plug 200 before the fuel injection valve 134 attached to the internal combustion engine 100 injects the fuel (between time T1 and time T3). Further, the ignition control unit 83 performs ignition control such that a second electric power is supplied as the preheating electric power to the spark plug 200 between a time when the fuel injection valve 134 injects the fuel and a time when the ignition electric power is supplied to the spark plug 200 (between time T3 and time T4). Here, the first electric power is larger than the second electric power. Thus, appropriate preheating electric power can be supplied to the spark plug 200 before and after the fuel injection.

[0103] (5) The ignition control unit 83 performs ignition control so that the spark plug 200 discharges current through the preheating electric energy to generate a spark before the fuel injection valve 134 injects fuel (between time T1 and time T3). Thus, preheating of the spark plug 200 can be effectively performed in the period before fuel injection without the possibility of misfire.

[0104] (6) The ignition control unit 83 performs ignition control so that a spark is not generated without discharging current from the spark plug 200 by the preheating electric energy between a time when the fuel injection valve 134 injects fuel and a time when the ignition electric energy is supplied to the spark plug 200 (between time T3 and time T4). Thus, preheating of the spark plug 200 can be performed while preventing misfire during the compression stroke.

[0105] (7) The ignition control unit 83 performs ignition control so that the preheating electric energy is supplied to the spark plug 200 a plurality of times per ignition. Thus, the preheating of the spark plug 200 can be reliably performed.

[0106] (8) The ignition control unit 83 performs ignition control so that the preheating electric energy is supplied to the spark plug 200 a plurality of times before the fuel injection valve 134 injects the fuel. Thus, the preheating of the spark plug 200 can be reliably performed.

[0107] (9) The ignition control unit 83 performs ignition control so that the preheating electric power is supplied to the spark plug 200 a plurality of times between a time when the fuel injection valve 134 injects the fuel and a time when the ignition electric power is supplied to the spark plug 200. Thus, the preheating of the spark plug 200 can be reliably performed.

[0108] (10) The internal combustion engine control device 1 includes the ignition control unit 83, which controls the energization of the ignition coil 300, which supplies electric power to the ignition coil 200, which discharges current into the cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit 83 controls the energization of the ignition coil 300 so that the spark plug 200 is supplied with the electric power to heat the spark plug 200 before the spark plug 200 performs ignition. Thus, the generation of hydrocarbons at the time of a cold start of the internal combustion engine 100 can be prevented, and the manufacturing cost of the exhaust catalyst can be reduced.

[0109] (11) The ignition control unit 83 controls the energization of the ignition coil 300 by continuously sending the pre-ignition signal Sp, which is a pulse signal having a first frequency, to an ignition electrode 340 connected to the ignition coil 300 before the fuel injection valve 134 attached to the internal combustion engine 100 injects the fuel (between time T1 and time T3). Further, the ignition control unit 83 controls the energization of the ignition coil 300 by continuously sending the pre-ignition signal Sp, which is a pulse signal having a second frequency, to the ignition electrode 340 between a time when the fuel injection valve 134 injects the fuel and a time when the spark plug 200 performs ignition (between time T3 and time T4). Here, the first frequency is lower than the second frequency. Thus, appropriate pre-ignition electrical energy can be reliably supplied to the spark plug 200 before and after fuel injection.

[0110] (12) The ignition control unit 83 controls the energization of the ignition coil 300 so that the spark plug 200 is supplied with the electric power for heating the spark plug 200 before the spark plug 200 performs ignition at the time of starting the internal combustion engine 100. Thus, the electric power required for preheating the spark plug 200 can be reliably supplied from the ignition coil 300 to the spark plug 200. - Second embodiment -

[0111] An internal combustion engine control apparatus according to a second embodiment of the present invention will be described below.

[0112] In the second embodiment, an example is described in which the control device 1 performs ignition control such that discharge (ignition) is performed in the spark plug 200 during the exhaust stroke in the combustion cycle. The configurations of the internal combustion engine 100 and the control device 1 according to the second embodiment are the same as those of the first embodiment, and thus, description thereof will be omitted. [Ignition signal output time]

[0113] The output timing of the ignition signal SA according to the second embodiment will be described below.

[0114] Fig. 9 shows an example of a timing chart showing the output timing of the ignition signal SA according to the second embodiment. Fig. 9(a) shows an example of a timing chart of the cold start timing of the internal combustion engine 100 and Fig. 9(b) shows an example of a timing chart after warm-up (during continuous operation) of the internal combustion engine 100.

[0115] In Fig. 9(a) and Fig. 9(b), each top row shows the ignition signal SA output from the ignition control unit 83 to the ignition coil 300. The ignition signal SA includes the main ignition signal Sa and an exhaust ignition signal Se output after the main ignition signal Sa. Similar to the first embodiment, the main ignition signal Sa is an ignition signal for the spark plug 200 for igniting the air-fuel mixture during the combustion stroke of the internal combustion engine 100.

[0116] The exhaust ignition signal Se, in turn, is an ignition signal for supplying the spark plug 200 with the electric power to cause the spark plug 200 to discharge electricity during at least the exhaust stroke of the internal combustion engine 100. When the exhaust ignition signal Se is output from the ignition control unit 83 to the ignition coil 300, the spark plug 200 can be caused to discharge electricity even during the exhaust stroke in which the burned fuel is discharged from the cylinder 150. Thus, it can be understood that the fuel in the air-fuel mixture that cannot be burned during the combustion stroke, such as fuel adhering to the wall surface of the cylinder 150 or the bottom surface of the piston 170, can be ignited and burned during exhaust. Thus, the generation of hydrocarbons (HC) can be prevented.

[0117] In the second embodiment, the ignition control unit 83 outputs the main ignition signal Sa for causing the spark plug 200 to discharge current (ignition) to the ignition coil 300 from time T4 to time T5 in the combustion stroke in the combustion cycle. Furthermore, the exhaust ignition signal Se for causing the spark plug 200 to discharge current (ignition) is output to the ignition coil 300 in the period after the combustion stroke in a combustion cycle, that is, in the period including at least the exhaust stroke.

[0118] As in Fig. As shown in Fig. 9, the exhaust ignition signal Se is repeatedly output a plurality of times from time T6 after the time T5 at which the output of the main ignition signal Sa is stopped. That is, the exhaust ignition signal Se is output in the period including at least the exhaust stroke in each cylinder 150, so that the spark plug 200 discharges a plurality of times. Here, the exhaust stroke is a period in which the exhaust valve 152 is opened after the combustion stroke of the internal combustion engine 100, and thus exhaust gases including the burned fuel are discharged from each cylinder 150. However, the exhaust ignition signal Se can be output only once.

[0119] As in Fig. As shown in Figure 9, in the period after time T6, a pulse signal is continuously output as the exhaust ignition signal Se at a predetermined duty cycle. The pulse width of the exhaust ignition signal Se is smaller than the pulse width of the main ignition signal Sa. Accordingly, the discharge cycle of the spark plug 200 by the exhaust ignition signal Se in the exhaust stroke is shorter than the discharge cycle of the spark plug 200 by the main ignition signal Sa in the combustion stroke.

[0120] When comparing Fig. 9(a) and Fig. 9(b) shows that the cycle of the pulse signal output as the exhaust ignition signal Se, that is, the discharge cycle of the spark plug 200 in the exhaust stroke, changes at the time of cold start and after warm-up. For example, at the time of cold start as shown in Fig. 9(a), the cycle (the discharge cycle of the spark plug 200) of the exhaust ignition signal Se is set in the range of 233 Hz to 10 kHz and after warming up as shown in Fig. As shown in Figure 9(b), the cycle (the discharge cycle of the spark plug 200) of the exhaust ignition signal Se is set within the range of 1 kHz to 10 kHz. Accordingly, the lower limit of the discharge cycle of the spark plug 200 in the exhaust stroke changes according to the elapsed time after the start of the internal combustion engine 100. Here, the cycle of the exhaust ignition signal Se changes in two steps; however, it may also change in three or more steps. Furthermore, the voltage generated in the ignition coil 300 according to the exhaust ignition signal Se is preferably equal to or greater than the dielectric breakdown voltage so that the spark plug 200 discharges current, and the pulse width of the exhaust ignition signal Se may be larger than that of the main ignition signal Sa.

[0121] As described above, in the second embodiment, the ignition control unit 83 outputs the exhaust ignition signal Se a plurality of times in the period including at least the exhaust stroke after outputting the main ignition signal Sa. Accordingly, during the exhaust stroke, the ignition control unit 83 controls the energization of the ignition coil 300 so that the ignition coil 300 supplies the spark plug 200 with the electric power to cause the spark plug 200 to discharge. When a high voltage is applied from the ignition coil 300 to the spark plug 200 based on the exhaust ignition signal Se, the spark plug 200 is discharged during the exhaust stroke of the internal combustion engine 100, and the fuel in the air-fuel mixture that cannot be combusted in the combustion stroke can be ignited and burned.

[0122] Thus, as described above, even if the air-fuel ratio is increased (the fuel is decreased) at the time of discharge (ignition) of the ignition coil 300 in the combustion stroke, the generation of hydrocarbons (HC) can be prevented.

[0123] In Fig. 9(a) and Fig. 9(b) shows the second phase from the top of the ON / OFF of the fuel injection valve 134. When the fuel injection valve 134 is actuated, a predetermined amount of fuel is injected through the fuel injection valve 134 into the cylinder 150 (the combustion chamber).

[0124] The lower row shows the in-cylinder pressure in cylinder 150 (in the combustion chamber). The in-cylinder pressure is measured by the combustion pressure sensor 140, and the measurement result of the combustion pressure sensor 140 is output. As described above, in the internal combustion engine 100, after the predetermined amount of fuel is injected by the fuel injection valve 134 to generate the air-fuel mixture in the combustion chamber, the air-fuel mixture is ignited at the time (time T5) when the main ignition signal Sa is turned off, and combustion occurs. Accordingly, the pressure in the cylinder 150 rises rapidly. The combustion pressure sensor 140 measures the in-cylinder pressure during the combustion cycle. [Spark plug control method]

[0125] An example of a control method of the spark plug 200 by the ignition control unit 83 is described below. Fig. 10 shows an example of a flowchart for illustrating a method of controlling the spark plug 200 by the ignition control unit 83 according to the second embodiment.

[0126] As in Fig. As shown in Figure 10, in step S201, the ignition control unit 83 determines whether the ignition switch is turned on or not. Thus, if it is determined that the ignition switch is turned on (step S201: YES), the process proceeds to step S202, and if it is determined that the switch is not turned on, that is, if it is determined that it is turned off (step S201: NO), the process returns to step S201.

[0127] In step S202, the ignition control unit 83 determines whether the main ignition signal Sa changes from ON to OFF. If the main ignition signal Sa changes from ON to OFF, that is, if the spark plug 200 discharges to ignite the air-fuel mixture (step S202: YES), the process proceeds to step S203. If it is determined that the signal does not change from ON to OFF (step S202: NO), the process returns to step S202.

[0128] In step S203, the ignition control unit 83 determines whether the operating state of the internal combustion engine 100 is a post-warm-up state. If the state is a post-warm-up state, that is, when a certain amount of time elapses after the internal combustion engine 100 starts operation and the internal combustion engine is in a continuous operating state (step S203: YES), the process proceeds to step S205. Conversely, if the state is not a post-warm-up state, that is, at the time of a cold start of the internal combustion engine 100 (step S203: NO), the process proceeds to step S204.

[0129] In step S204, the ignition control unit 83 sets the output cycle of the exhaust ignition signal Se to be long. After step S204 is executed, the ignition control unit 83 proceeds to step S206 and, in step S206, outputs the exhaust ignition signal Se at the output cycle set in step S204. Accordingly, discharge control (ignition control) is performed on the spark plug 200 so that the spark plug 200 discharges current using the electrical energy supplied from the ignition coil 300 to the spark plug 200 during the exhaust stroke to generate a spark.

[0130] In step S205, the ignition control unit 83 sets the output cycle of the exhaust ignition signal Se to be short. After step S205 is executed, the ignition control unit 83 proceeds to step S206 and, in step S206, outputs the exhaust ignition signal Se at the output cycle set in step S205. Accordingly, discharge control (ignition control) is performed on the spark plug 200 so that the spark plug 200 discharges current using the electrical energy supplied from the ignition coil 300 to the spark plug 200 during the exhaust stroke to generate a spark.

[0131] After the exhaust ignition signal Se is output in step S206, the process returns to step S202. Accordingly, each time the spark plug 200 discharges and performs the combustion stroke, the discharge control (ignition control) is performed on the spark plug 200 so that the exhaust ignition signal Se is output in the period including at least the following exhaust stroke, and the output cycle of the exhaust ignition signal Se changes at the time of a cold start and after warm-up. When a predetermined time elapses after the internal combustion engine 100 starts operating, the timing shown in the flowchart of Fig. 10 can be terminated and the output of the exhaust ignition signal Se can be stopped.

[0132] As described above, the second embodiment includes the spark plug 200 disposed in the cylinder 150 and the ignition control unit 83 that controls the discharge of the spark plug 200. The ignition control unit 83 is configured to supply electrical energy from the ignition coil 300 to the spark plug 200 during at least the exhaust stroke of the internal combustion engine 100. With this configuration, the fuel remaining in the air-fuel mixture discharged from each cylinder 150 in the internal combustion engine 100 can be combusted, thus preventing the generation of hydrocarbons (HC) at the time of a cold start.

[0133] In the second embodiment, the ignition control unit 83 is configured to supply the electric discharge energy from the ignition coil 300 to the spark plug 200 a plurality of times during the period including at least the exhaust stroke of the internal combustion engine 100. With this configuration, the spark plug 200 can reliably discharge electricity during the exhaust stroke, so that the generation of hydrocarbons (HC) can be reliably prevented.

[0134] According to the second embodiment of the present invention described above, the following operational effects are achieved.

[0135] (1) The internal combustion engine control device 1 includes the ignition control unit 83, which performs ignition control for controlling the spark plug 200, which discharges current into the cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit 83 performs the ignition control in such a way that that the electrical energy for causing the spark plug 200 to discharge current is supplied to the spark plug 200 during a period including at least the exhaust stroke in which the fuel is exhausted from the cylinder 150 after combustion (a period after time T6). Thus, the generation of hydrocarbons at the time of a cold start of the internal combustion engine 100 can be prevented, and the manufacturing cost of the exhaust catalyst can be reduced.

[0136] (2) The exhaust stroke is a period during which the exhaust valve 152 of the internal combustion engine 100 is open. Thus, by opening the exhaust valve 152, the fuel remaining in the air-fuel mixture discharged from each cylinder 150 can be reliably combusted and the generation of hydrocarbons can be prevented.

[0137] (3) The ignition control unit 83 performs ignition control so that the spark plug 200 discharges current a plurality of times during the period. Thus, the spark plug 200 can be reliably caused to discharge current during the exhaust stroke, and the fuel remaining in the exhausted air-fuel mixture can be burned.

[0138] (4) One discharge cycle of the spark plug 200 during the period is shorter than one discharge cycle when the spark plug 200 ignites the fuel during the combustion stroke. Thus, the fuel remaining in the air-fuel mixture discharged from the cylinder 150 can be reliably burned at any time during the exhaust stroke.

[0139] (5) The ignition control unit 83 performs ignition control such that the discharge cycle of the spark plug 200 is within a range from a predetermined lower limit to an upper limit, and the lower limit changes according to a time elapsed after the start of the internal combustion engine 100. Thus, the generation of hydrocarbons can be reliably prevented both at the time of a cold start and after warm-up.

[0140] The first embodiment and the second embodiment described above can be combined. That is, at the time of a cold start of the internal combustion engine 100, the ignition control unit 83 outputs the pre-ignition signal Sp before the first explosion to preheat the spark plug 200 and outputs the exhaust ignition signal Se to discharge the spark plug 200 in a period including at least the exhaust stroke, thereby preventing the generation of hydrocarbons (HC). Further, after warm-up (during continuous operation) of the internal combustion engine 100, the ignition control unit 83 outputs the exhaust ignition signal Se to discharge the spark plug 200 in a period including at least the exhaust stroke, thereby preventing the generation of hydrocarbons (HC). With this configuration, the internal combustion engine control device 1 can be configured to achieve each of the operational effects described in the first embodiment and the second embodiment.

[0141] In each of the embodiments described above, any functional configuration of the Fig. The control device 1 described in Figure 3 can be implemented by software executed by the MPU 50 as described above or by other hardware, such as a field programmable gate array (FPGA). In addition, these can be combined and used.

[0142] The above-described embodiments and various modifications are purely exemplary, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. Furthermore, although various embodiments and modifications have been described above, the present invention is not limited to their contents. Other embodiments considered within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. List of reference symbols 1 control device 10 analog input unit 20 digital input unit 30 A / D converters 40 RAM 50 MPU 60 ROM 70 I / O port 80 output circuit 81 Total control unit 82 Fuel injection control unit 83 Ignition control unit 84 Cylinder determination unit 85 Angle information generation unit 86 Speed ​​information generation unit 87 Intake flow measuring unit 88 Load information generation unit 89 Water temperature measuring unit 100 combustion engine 110 air filters 111 Intake pipe 112 intake manifold 113 Throttle valve 113a Throttle opening sensor 114 Flow sensor 115 Intake air temperature sensor 120 sprocket 121 Crank angle sensor 122 Water temperature sensor 123 Crankshaft 125 accelerator pedal 126 Accelerator pedal position sensor 130 fuel tank 131 Fuel pump 132 pressure regulators 133 Fuel line 134 Fuel injection valve 140 Combustion pressure sensor 150 cylinders 151 intake valve 152 exhaust valve 160 exhaust manifold 161 Three-way catalyst 162 Upstream air-fuel ratio sensor 163 Downstream air-fuel ratio sensor 170 pistons 200 spark plug 210 Center electrode 220 outer electrode 230 Insulator 300 ignition coil 310 Primary coil 320 secondary coil 330 DC power supply 340 ignition electrode 350 loading quantity recording unit 360 discharge quantity recording unit 400 electrical circuit

Claims

[1] Internal combustion engine control device (1), comprising: an ignition control unit (83) which performs an ignition control for controlling a spark plug (200) which discharges current in a cylinder (150) of an internal combustion engine (100) to ignite fuel, wherein the ignition control unit (83) performs the ignition control such that a predetermined electrical ignition energy is supplied to the spark plug (200) when the spark plug (200) performs the ignition, and a predetermined electrical preheating energy smaller than the electrical ignition energy is supplied to the spark plug (200) before the spark plug (200) performs the ignition. [2] An internal combustion engine control device (1) according to claim 1, wherein the ignition control unit (83) performs the ignition control such that the preheating electric power is supplied to the spark plug (200) before a fuel injection valve (134) attached to the internal combustion engine (100) injects the fuel. [3] An internal combustion engine control device (1) according to claim 1 or 2, wherein the ignition control unit (83) performs the ignition control so that the preheating electric power is supplied to the spark plug (200) between a time when a fuel injection valve (134) attached to the internal combustion engine (100) injects the fuel and a time when the ignition electric power is supplied to the spark plug (200). [4] Internal combustion engine control device (1) according to claim 1, wherein the ignition control unit (83) performs the ignition control such that a first electrical energy is supplied as the electrical preheating energy to the spark plug (200) before a fuel injection valve (134) attached to the internal combustion engine (100) injects the fuel, the ignition control unit (83) performs the ignition control such that a second electrical energy as the preheating electrical energy is supplied to the spark plug (200) between a time at which the fuel injection valve (134) injects the fuel and a time at which the ignition electrical energy is supplied to the spark plug (200), and the first electrical energy is greater than the second electrical energy. [5] An internal combustion engine control device (1) according to claim 2 or 4, wherein the ignition control unit (83) performs the ignition control so that the spark plug (200) discharges current by the preheating electric energy to generate a spark before the fuel injection valve (134) injects the fuel. [6] An internal combustion engine control device (1) according to claim 3 or 4, wherein the ignition control unit (83) performs the ignition control so that a spark is not generated without discharging current from the ignition plug (200) by the preheating electric energy between a time when the fuel injection valve (134) injects the fuel and a time when the ignition electric energy is supplied to the ignition plug (200). [7] The internal combustion engine control device (1) according to claim 1, wherein the ignition control unit (83) performs the ignition control such that the preheating electric power is supplied to the spark plug (200) a plurality of times per ignition. [8] An internal combustion engine control device (1) according to claim 2 or 4, wherein the ignition control unit (83) performs the ignition control such that the preheating electric power is supplied to the spark plug (200) a plurality of times before the fuel injection valve (134) injects the fuel. [9] An internal combustion engine control device (1) according to claim 3 or 4, wherein the ignition control unit (83) performs the ignition control such that the preheating electric power is supplied to the spark plug (200) a plurality of times between a time when the fuel injection valve (134) injects the fuel and a time when the ignition electric power is supplied to the spark plug (200). [10] Internal combustion engine control device (1), comprising: an ignition control unit (83) which controls the excitation of an ignition coil (300), supplies electrical energy to a spark plug (200) which discharges current in a cylinder (150) of an internal combustion engine (100) to ignite fuel, wherein the ignition control unit (83) controls the excitation of the ignition coil (200) by continuously sending a pulse signal having a first frequency to an ignition electrode (340) connected to the ignition coil (200) so that the spark plug (200) is supplied with the electrical energy for heating the spark plug (200) before the spark plug (200) performs the ignition at a time of starting the internal combustion engine (100) and before a fuel injection valve (134) attached to the internal combustion engine (100) injects the fuel, and the ignition control unit (83) controls the excitation of the ignition coil (200) by continuously sending a pulse signal having a second frequency to the ignition electrode (340) between a time at which the fuel injection valve (134) injects the fuel and a time at which the spark plug (200) performs the ignition, so that the spark plug (200) is supplied with the electrical energy for heating the spark plug (200) before the spark plug (200) performs the ignition at a time of starting the internal combustion engine (100). [11] An internal combustion engine control device (1) according to claim 10, wherein the first frequency is lower than the second frequency. [12] The internal combustion engine control device (1) according to claim 1, wherein the ignition control unit (83) performs the ignition control so that an electric power for causing the spark plug (200) to discharge current is supplied to the spark plug (200) in a period including at least one exhaust stroke in which the fuel is exhausted from the cylinder (150) after combustion. [13] The internal combustion engine control device (1) according to claim 12, wherein the exhaust stroke is a period during which an exhaust valve of the internal combustion engine (100) is open. [14] The internal combustion engine control device (1) according to claim 12, wherein the ignition control unit (83) performs the ignition control so that the spark plug (200) discharges current a plurality of times during the period. [15] The internal combustion engine control device (1) according to claim 14, wherein a discharge cycle of the spark plug (200) is shorter in time than a discharge cycle when the spark plug (200) performs ignition. [16] Internal combustion engine control device (1) according to claim 15, wherein the ignition control unit (83) carries out the ignition control in such a way that the discharge cycle of the spark plug (200) in the period is within a range from a predetermined lower limit to an upper limit, and the lower limit value is changed according to a time elapsed after the start of the internal combustion engine (100). [17] Internal combustion engine control device (1), comprising: an ignition control unit (83) which performs an ignition control for controlling a spark plug (200) which discharges current in a cylinder (150) of an internal combustion engine (100) to ignite fuel, wherein the ignition control unit (83) performs the ignition control such that, in a period comprising at least one exhaust stroke in which the fuel is discharged from the cylinder (150) after combustion, an electrical energy for causing the spark plug (200) to discharge current is supplied to the spark plug (200) and the spark plug (200) performs discharges a plurality of times, a discharge cycle of the spark plug (200) in a period of time is within a range from a predetermined lower limit to an upper limit and is shorter than a discharge cycle when the spark plug (200) performs the ignition, and the ignition control unit (83) carries out the ignition control such that the lower limit value changes according to a time elapsed after the start of the internal combustion engine (100).

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