Internal combustion engine control device and internal combustion engine control method

Abstract

One task is to appropriately control the thermal balance of an ignition device to prevent an increase in its size and cost. An internal combustion engine control unit controls an internal combustion engine by interrupting the current flowing through an ignition coil according to a predetermined ignition timing. The internal combustion engine control unit comprises a demand-setting unit, a setting unit, and an ignition control unit. The demand-setting unit determines a required excitation level of the ignition coil based on the rotational speed of the internal combustion engine. The setting unit adjusts the excitation level of the ignition coil according to the temperature of the ignition device and the required excitation level.The ignition control unit controls the interruption state of the ignition coil according to the excitation strength of the ignition coil set by the adjustment unit.

Description

Technical area

[0001] The present invention relates to an internal combustion engine control device and an internal combustion engine control method. Technical background

[0002] In recent years, to improve a vehicle's fuel consumption, lean-burn combustion technology, in which an air-fuel mixture exceeding a theoretical air-fuel ratio (the fuel is thinner) is burned to operate the internal combustion engine, and exhaust gas recirculation technology, in which part of the exhaust gas is recaptured and sucked in after combustion, have been developed.

[0003] In this type of internal combustion engine, due to the use of a lean air-fuel mixture and the implementation of exhaust gas recirculation, sparks are less likely to be blown to the spark plug. Therefore, the ignitability (i.e., the amount of ignition energy) of the ignition device required for flame formation in the combustion chamber is increased compared to a case where the air-fuel mixture is ignited at the theoretical air-fuel ratio. Therefore, the amount of heat acting on the ignition coil per unit time increases.

[0004] For example, PTL 1 discloses an engine ignition device configured to correct ignition energy according to a change in intake manifold pressure. The engine ignition device disclosed in PTL 1 increases ignition energy by extending the energization time of an ignition coil based on intake manifold pressure Pm to prevent misfire during boosting. Therefore, a stable combustion state is ensured even in a situation where sparks are difficult to fly to the spark plug due to boosting. Citation listPatent literature

[0005] PTL 1: JP 2000-054941 A Summary of the inventionTechnical problem

[0006] However, the engine ignition device disclosed in PTL 1 does not consider the heat balance of the ignition coil. For example, when the internal combustion engine is continuously operated at high load in a state where the intake manifold pressure Pm is increased due to supercharging, the energization time of the ignition coil is prolonged. Therefore, a situation remains in the ignition device where the ignition energy is increased, that is, the amount of heat per unit time is high. Therefore, the temperature of the ignition device may exceed the specified rated temperature.

[0007] One conceivable countermeasure to this problem is to design the ignition coil's heat dissipation by considering the maximum amount of heat the ignition coil can dissipate per unit time during continuous high-load operation or operation under harsh environmental conditions, such as high outside temperatures in summer. However, this measure introduces new problems such as increasing the size and cost of the ignition device.

[0008] In view of the above problems, an object of the present invention is to provide an internal combustion engine control device and an internal combustion engine control method, whereby the heat balance of an ignition device is appropriately controlled and an increase in the size and cost of the ignition device is prevented. Solution to the problem

[0009] To solve the above problems and achieve the present object, an internal combustion engine control device according to one aspect of the present invention controls an internal combustion engine by interrupting a current flowing through an ignition coil of an ignition device according to a predetermined ignition timing. The internal combustion engine control device includes a request setting unit, a setting unit, and an ignition control unit. The request setting unit determines a required excitation intensity of the ignition coil based on the rotational speed of the internal combustion engine. The setting unit sets the excitation intensity of the ignition coil according to the temperature related to the ignition device and the required excitation intensity. The ignition control unit controls the interruption state of the ignition coil according to the excitation intensity of the ignition coil set by the setting unit.

[0010] An internal combustion engine control method according to one aspect of the present invention is a method for controlling an internal combustion engine by interrupting a current flowing through an ignition coil of an ignition device according to a predetermined ignition timing. In this internal combustion engine control method, the request setting unit determines a requested excitation intensity of the ignition coil based on the rotational speed of the internal combustion engine. Next, the setting unit sets the excitation intensity of the ignition coil according to the temperature related to the ignition device and the requested excitation intensity. Then, the ignition control unit controls the interruption state of the ignition coil according to the excitation intensity of the ignition coil set by the setting unit. Advantageous effects of the invention

[0011] According to one aspect of the present invention, the heat balance of the ignition device in the internal combustion engine can be appropriately controlled and the increase in the size and cost of the ignition device can be prevented.

[0012] It should be noted that various problems, configurations and effects described above will become clear from the following description of the embodiments. Brief description of the drawings

[0013] They show: Fig. 1 is an overall configuration diagram of a basic configuration example of an internal combustion engine according to an embodiment, Fig. 2 is a partially enlarged view of a spark plug according to the embodiment, Fig. 3 is a functional block diagram showing a functional configuration of an internal combustion engine control device according to the embodiment; Fig. 4 is a circuit diagram of an example of an electrical circuit having an ignition coil, Fig. 5 is a diagram explaining a relationship between the temperature of an electrode, the minimum ignition energy and the air-fuel ratio, Fig. 6 an example of a discharge waveform of a multiple ignition, Fig. 7 is a conceptual diagram showing the relationship between the supplyable discharge energy, the required discharge energy and the difference therebetween with respect to the temperature of the ignition coil, Fig. 8 is a conceptual diagram showing a relationship between temperature and discharge energy of a conventional ignition coil, Fig. 9 is a conceptual diagram showing a relationship between the temperature of an ignition coil and the discharge energy in a case where the present invention is applied, Fig. 10 is a flowchart of processing of the ignition and fuel injection control according to a first embodiment, Fig. 11 a conceptual diagram of weights and biases of neurons forming a neural network model, Fig. 12 is a diagram for explaining a method for realizing the operation of each target variable by the neural network model according to the first embodiment; Fig. 13 is a conceptual diagram of a neural network model used for processing the ignition and fuel injection control according to the first embodiment, Fig. 14 is a correspondence table showing a relationship between a target variable and an explanatory variable in a case where the neural network model according to the first embodiment is used, Fig. 15 is a selection table of influencing factors when explanatory variables for estimating the ignition coil temperature are selected according to the first embodiment, Fig. 16 is a diagram for explaining a limit residence time map according to a second embodiment, Fig. 17 is a diagram for explaining a request dwell time map according to the second embodiment, Fig. 18 is a diagram for explaining a voltage correction coefficient map according to the second embodiment, Fig. 19 is a flowchart of processing of the ignition and fuel injection control according to the second embodiment, Fig. 20 is a diagram for explaining a temperature correction coefficient map according to a third embodiment, Fig. 21 is a flowchart of the processing of the ignition and fuel injection control according to the third embodiment, Fig. 22 is a diagram for explaining a low temperature demand residence time map according to a fourth embodiment, Fig. 23 is a diagram for explaining a high temperature demand residence time map according to the fourth embodiment, Fig. 24 is a flowchart of processing of the ignition and fuel injection control according to the fourth embodiment, and Fig. 25 is a circuit diagram showing an example of an electrical circuit including an ignition coil according to a fifth embodiment. Description of embodiments< First embodiment >

[0014] An internal combustion engine control device according to a first embodiment will be described below. Note that corresponding parts in the drawings are designated by the same reference numerals. [Combustion engine system]

[0015] First, a configuration of an internal combustion engine system according to an embodiment will be described. Fig. 1 is an overall configuration diagram showing a basic configuration example of the internal combustion engine according to the embodiment of the present invention.

[0016] One in Fig. 1 may have a single cylinder or multiple cylinders, but according to the embodiment, an internal combustion engine 100 with four cylinders is described as an example.

[0017] As in Fig. As shown in Figure 1, in the internal combustion engine 100, air drawn from the outside (intake air) flows through an air cleaner 110, an intake pipe 111, and an intake manifold 112. The air flowing through the intake manifold 112 flows into each cylinder 150 when an intake valve 151 is opened. The amount of air flowing into each cylinder 150 is adjusted by a throttle valve 113. The amount of air adjusted by the throttle valve 113 is measured by a flow rate sensor 114.

[0018] The throttle valve 113 is provided with a throttle opening degree sensor 113a that detects the throttle opening degree. The throttle valve opening information detected by the throttle opening degree sensor 113a is output to a control device (electronic control unit: ECU) 1.

[0019] According to the present embodiment, an electronic throttle valve driven by an electric motor is used as the throttle valve 113. However, other types may be used as the throttle valve according to the present invention as long as the air flow rate can be appropriately adjusted.

[0020] The temperature of the air flowing into each cylinder 150 is detected by an intake air temperature sensor 115.

[0021] A crank angle sensor 121 is provided radially outside a ring gear 120 attached to a crankshaft 123. The crank angle sensor 121 detects the rotation angle of the crankshaft 123. According to the present embodiment, the crank angle sensor 121 detects the rotation angle of the crankshaft 123 every 10° and in each combustion cycle.

[0022] A water temperature sensor 122 is provided in a water jacket (not shown) of a cylinder head. The water temperature sensor detects the temperature of the cooling water of the internal combustion engine 100.

[0023] Additionally, the vehicle is equipped with an accelerator pedal position sensor 126 that detects the amount of deflection (depression) of an accelerator pedal 125. The accelerator pedal position sensor 126 detects a driver-requested torque. The requested torque, as part of the torque detected by the accelerator pedal position sensor 126, is output to the engine control device 1 described later. The engine control device 1 controls the throttle valve 113 based on the requested torque.

[0024] The fuel stored in the fuel tank 130 is sucked and pressurized by the fuel pump 131. The fuel sucked and pressurized by the fuel pump 131 is adjusted to a predetermined pressure by a pressure regulator 132 provided in the fuel tank 130 together with the fuel pump 131. Then, the fuel adjusted to a predetermined pressure is supplied to a fuel injector 134 through a fuel line 133 and injected into each cylinder 150. Note that excess fuel generated by the pressure adjustment by the pressure regulator 132 is discharged from the pressure regulator 132 to the fuel tank 130.

[0025] The control of the fuel injection device 134 is performed based on a fuel injection pulse (control signal) of a fuel injection control unit 82 (see Fig. 3) of the internal combustion engine control device 1 described later.

[0026] An in-cylinder pressure sensor (also referred to as a cylinder pressure sensor or combustion pressure sensor) 140 is provided in a cylinder head (not shown) facing a combustion chamber of the internal combustion engine 100. The in-cylinder pressure sensor 140 is provided in the cylinder 150 and detects the pressure (combustion pressure) in the cylinder 150. For example, a piezoelectric or relative pressure sensor is used as the in-cylinder pressure sensor 140. This allows the pressure within the cylinder 150 to be detected.

[0027] An exhaust valve 152 and an exhaust manifold 160 are attached to each cylinder 150. When the exhaust valve 152 opens, the exhaust gas from the cylinder 150 is expelled to the exhaust manifold 160. The exhaust manifold 160 expels the burned gas (exhaust gas) from the cylinder 150. A three-way catalyst 161 is provided on the exhaust side of the exhaust manifold 160. The three-way catalyst 161 purifies the exhaust gas. The exhaust gas purified by the three-way catalyst 161 is discharged into the atmosphere.

[0028] An upstream air-fuel ratio sensor 162 is provided on the upstream side of the three-way catalyst 161. The upstream air-fuel ratio sensor 162 outputs an oxygen concentration signal related to the air-fuel ratio of the exhaust gas discharged from each cylinder 150. The upstream air-fuel ratio sensor 162 according to the present embodiment is a so-called linear air-fuel ratio sensor that detects the air-fuel ratio (oxygen concentration) of the exhaust gas discharged from each cylinder 150 as a voltage that changes proportionally (linearly) with the air-fuel ratio.

[0029] 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 signal corresponding to the oxygen concentration related to the air-fuel ratio of the exhaust gas purified by the three-way catalyst 161. The downstream air-fuel ratio sensor 163 according to the present embodiment is a so-called O2 sensor, which outputs a detection signal that changes binary depending on whether the air-fuel ratio is thicker (richer) or thinner (leaner) than the theoretical air-fuel ratio.

[0030] A spark plug 200 is provided at a portion opposite each combustion chamber of each cylinder 150. The spark plug 200 generates sparks by discharge (ignition), and the sparks ignite an air-fuel mixture in the cylinder 150. As a result, explosive combustion occurs in the cylinder 150 and a piston 170 is depressed. When the piston 170 is depressed, the crankshaft 123 rotates. An ignition coil 300, which generates (amplified) a discharge voltage supplied to the spark plug 200, is connected to the spark plug 200.

[0031] Output signals from various sensors such as the throttle opening sensor 113a, the flow rate sensor 114, the crank angle sensor 121, the accelerator pedal position sensor 126, the water temperature sensor 122, and the in-cylinder pressure sensor 140 described above are input to the internal combustion engine control device 1 (hereinafter referred to as "control device 1"). The control device 1 controls the amount of air passing through the throttle valve 113, the fuel injection amounts of the fuel pump 131 and the fuel injector 134, the ignition timing of the spark plug 200 by the ignition coil 300, and the like based on signals from these various sensors. [Spark plug]

[0032] Next, the spark plug 200 is removed with reference to Fig. 2 described.

[0033] Fig. Figure 2 is a partially enlarged view of the spark plug 200.

[0034] As in Fig. As shown in Figure 2, the spark plug 200 includes a center electrode 210 and an outer electrode 220. The center electrode 210 is held by a piston base (not shown) via an insulator 230. Accordingly, the center electrode 210 is insulated. The outer electrode 220 is grounded.

[0035] When a voltage is generated in the ignition coil 300 (see Fig. 1), a predetermined voltage (for example, 20,000 V to 40,000 V) is applied to the center electrode 210. 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. Sparks generated by the discharge then ignite an air-fuel mixture (gas component) in the cylinder 150.

[0036] It should be noted that the voltage at which the discharge (ignition) occurs as a result of electrical breakdown of the gas component in cylinder 150 depends on the state of the gas (the air-fuel mixture in the cylinder) located between the center electrode 210 and the outer electrode 220 and the internal pressure of cylinder 150. The voltage at which this discharge occurs is called the dielectric breakdown voltage.

[0037] The discharge control (ignition control) of the spark plug 200 is carried out by an ignition control unit 83 (see Fig. 3) the control device 1, as described later. [Hardware configuration of the control device]

[0038] Next, an overall configuration of the hardware of the control device 1 will be described.

[0039] As in Fig. 1, the control device 1 includes an analog input unit 10, a digital input unit 20, an analog / digital (A / D) conversion unit 30, a random access memory (RAM) 40, a microprocessing unit (MPU) 50, a read-only memory (ROM) 60, an input / output (I / O) port 70, and an output circuit 80.

[0040] The analog input unit 10 receives analog output signals from various sensors such as the throttle opening degree sensor 113a, the flow rate sensor 114, the accelerator pedal position sensor 126, the upstream air-fuel ratio sensor 162, the downstream air-fuel ratio sensor 163, the in-cylinder pressure sensor 140, and the water temperature sensor 122.

[0041] The A / D converter 30 is connected to the analog input unit 10. The analog output signals from the various sensors input to the analog input unit 10 are subjected to signal processing such as noise removal and then converted into digital signals by the A / D converter 30. The digital signal converted by the A / D converter 30 is then stored in the RAM 40.

[0042] A digital output signal from the crank angle sensor 121 is input to the digital input unit 20. The digital input unit 20 is connected to the I / O port 70. The digital output signal input to the digital input unit 20 is stored in the RAM 40 via the I / O port 70.

[0043] Each output signal stored in the RAM 40 is subjected to arithmetic processing by the MPU 50.

[0044] The MPU 50 executes a control program (not shown) stored in the ROM 60 to process the output signal stored in the RAM 40 according to the control program. The MPU 50 calculates a control value that defines the magnitude of operation of each operating element (for example, the throttle valve 113, the fuel injector 134, the fuel pump 131, the ignition coil 300, and the like) that drives the internal combustion engine 100 according to the control program, and temporarily stores the control value in the RAM 40.

[0045] The control value stored in RAM 40, which defines the strength of operation of each actuator, is output to the output circuit 80 via the I / O port 70.

[0046] The driving devices of the throttle valve 113, the fuel pump 131, the fuel injector 134 and the ignition coil 300 are electrically connected to the output circuit 80. [Functional block of the control device]

[0047] Next, a functional configuration of the control device 1 will be described with reference to Fig. 3 described.

[0048] Fig. 3 is a functional block diagram showing the functional configuration of the control device 1.

[0049] As in Fig. As shown in Fig. 3, the control device 1 is provided with the above-described output circuit 80. According to the present embodiment, the output circuit 80 includes an overall control unit 81, a fuel injection control unit 82, and an ignition control unit 83. Furthermore, the control device 1 is provided with a cylinder discrimination unit 84, an angle information generation unit 85, a rotational speed information generation unit 86, an intake amount measurement unit 87, a load information generation unit 88, a water temperature measurement unit 89, and a voltage measurement unit 90.

[0050] The angle information generation unit 85 measures the crank angle of the crankshaft 123 based on the digital output signal of the crank angle sensor 121. The cylinder discrimination unit 84 determines which stroke (for example, a power stroke, a compression stroke, an intake or compression stroke as shown in Fig. 6) of each cylinder 150 of the internal combustion engine 100 corresponds to the current crank angle measured by the angle information generation unit 85. The rotational speed information generation unit 86 measures the engine rotational speed.

[0051] The intake quantity measuring unit 87 measures the amount of air drawn into the cylinder 150 based on an output signal from the flow rate sensor 114. The load information generating unit 88 calculates the driver's requested torque based on the output signal from the accelerator pedal position sensor 126. The water temperature measuring unit 89 measures the temperature of the engine cooling water. The voltage measuring unit 90 measures the voltage of a DC power supply 330 (battery of the internal combustion engine 100), as shown in Fig. 4 shown. [Total control unit]

[0052] The overall control unit 81 includes an ignition timing setting unit 811, a request setting unit 812, a setting unit 813, an ignition device temperature estimation unit 814, a fuel injection amount setting unit 815, and a fuel injection timing setting unit 816.

[0053] The ignition timing setting unit 811 optimally calculates the ignition timing IGADV, which is the main operation quantity of the internal combustion engine 100, based on the operating state of the internal combustion engine 100 obtained from the outputs of various sensors such as an output signal S2 of the in-cylinder pressure sensor 140.

[0054] The requirement setting unit 812 calculates a required excitation time (required excitation intensity) based on the operating state of the internal combustion engine 100, which was obtained from outputs of various sensors such as the rotational speed NE and the power supply voltage VB of the internal combustion engine 100. The required excitation time is a time required at the ignition time for exciting a primary coil 310 (see Fig. 5) the ignition coil 300.

[0055] The setting unit 813 calculates the excitation time for exciting the primary coil 310 (see Fig. 5) the ignition coil 300 based on a temperature value (the ignition coil temperature) TC relating to the ignition device obtained from the ignition device temperature estimation unit 814 and the required energization time (required energization intensity) obtained from the requirement setting unit.

[0056] The igniter temperature estimation unit 814 calculates an igniter-related temperature value (ignition coil temperature) TC using a neural network model with a preselected explanatory variable as input.

[0057] The fuel injection amount setting unit 815 optimally calculates a fuel injection amount, which is a main operating amount of the internal combustion engine 100, based on an operating state of the internal combustion engine 100 obtained from outputs of various sensors such as the rotational speed NE and the power supply voltage VB of the internal combustion engine 100.

[0058] The fuel injection timing setting unit 816 optimally calculates the opening / closing operation time of the fuel injection valve in the fuel injection device 134 based on the operating state of the internal combustion engine 100 obtained from outputs of various sensors such as the rotational speed NE of the internal combustion engine 100 and the fuel injection amount obtained by the fuel injection amount setting unit 815. [Fuel injection control unit]

[0059] The fuel injection control unit 82 controls the energization timing and time of the fuel injection valve. The fuel injection control unit 82 generates a fuel injection pulse based on fuel control information input from the overall control unit 81. The fuel injection control unit 82 supplies the generated fuel injection pulse to the fuel injection control unit 82. The fuel injector 134 is driven according to the fuel injection pulse.

[0060] The fuel control information includes, for example, a value of the fuel injection amount obtained from the fuel injection amount setting unit 815, the number of fuel injections in each combustion cycle of the internal combustion engine 100, the opening / closing operation time of the fuel injection valve obtained from the fuel injection timing setting unit 816, and the like. [Ignition control unit]

[0061] The ignition control unit 83 controls the excitation timing and excitation time of the ignition coil 300. The ignition control unit 83 calculates the excitation start time (excitation start crank angle) of the primary coil 310 based on the ignition control information input from the overall control unit 81. The excitation start time of the primary coil 310 is a time obtained by tracing the excitation time series from the ignition timing at which the current supplied to the primary coil 310 is cut off.

[0062] The ignition control information includes, for example, engine rotation speed information S5, a value of the ignition timing (crank angle from the spark generation timing to the compression top dead center of the internal combustion engine), a value of the excitation time obtained from the setting unit 813, and the like.

[0063] The ignition control unit 83 initiates the excitation of the primary coil 310 based on the calculated excitation start time and outputs an ignition signal SA (see Fig. 4) to interrupt the excitation of the primary coil 310 based on the ignition timing. This causes the air-fuel mixture to be ignited by the spark plug 200. [Electrical circuit containing the ignition coil]

[0064] Next, an electrical circuit having an ignition coil is described with reference to Fig. 4 described.

[0065] Fig. 4 is a diagram for explaining an electrical circuit including an ignition coil.

[0066] One in Fig. The electrical circuit 500 shown in Figure 4 includes the ignition coil 300. The ignition coil 300 includes a primary coil 310 having a predetermined number of turns and a secondary coil 320 having a greater number of turns than the primary coil 310.

[0067] One end of the primary coil 310 is connected to the DC power supply 330. This applies a predetermined voltage (for example, 12 V) to the primary coil 310. The other end of the primary coil 310 is connected to a drain (D) terminal of an igniter (excitation control circuit) 340 and grounded via the igniter 340. A transistor, a field-effect transistor (FET), or the like is used as the igniter 340.

[0068] A gate (G) terminal of the igniter 340 is connected to the ignition control unit 83 via a temperature switching unit 350. The temperature switching unit 350 is installed to prevent damage due to overheating of the ignition coil 300. When the temperature of the ignition coil 300 becomes greater than or equal to a predetermined threshold value A (a first temperature), the temperature switching unit 350 interrupts the ignition signal SA output from the ignition control unit 83 to the igniter 340.

[0069] When the temperature switching unit 350 interrupts the ignition signal SA, the excitation of the igniter 340 is interrupted, so that overheating of the igniter 340 can be prevented. The ignition signal SA, which is output by the ignition control unit 83 when the temperature detected by a temperature detection unit 351 falls below the first temperature, is applied to the gate (G) terminal of the igniter 340.

[0070] When the ignition signal SA is applied to the gate (G) terminal of the igniter 340, the drain (D) terminal and a source (S) terminal of the igniter 340 are energized, and a current flows between the drain (D) terminal and the source (S) terminal. As a result, the ignition signal SA is output from the ignition control unit 83 to the primary coil 310 of the ignition coil 300 via the igniter 340. As a result, a current flows through the primary coil 310, and energy (electrical energy) is accumulated.

[0071] When the output of the ignition signal SA from the ignition control unit 83 is stopped, the current flowing through the primary coil 310 is interrupted. This generates a high voltage in the secondary coil 320 that corresponds to the ratio of the number of turns between the coil and the primary coil 310.

[0072] The high voltage generated in the secondary coil 320 is applied to the middle electrode 210 (see Fig. 2) the spark plug 200. This creates a potential difference between the center electrode 210 of the spark plug 200 and the outer electrode 220. When the potential difference created between the center electrode 210 and the outer electrode 220 becomes greater than or equal to a dielectric breakdown voltage Vm of the ambient gas (the air-fuel mixture in the cylinder 150), a dielectric breakdown occurs in the gas component, and a discharge occurs between the center electrode 210 and the outer electrode 220. This ignites the fuel (the air-fuel mixture). The spark plug 200 and the electrical circuit 500 including the ignition coil 300 correspond to the ignition device according to the present invention.

[0073] The discharge path created between the center electrode 210 and the outer electrode 220 has a high temperature of several thousand °C. Because the discharge path is in contact with the ambient gas and the electrodes 210 and 220, the heat energy generated by the discharge is distributed between the ambient gas and the electrodes 210 and 220. The heat energy transferred to the ambient gas heats (preheats) the ambient gas and the electrodes 210 and 220, promoting ignition. [Electrode temperature, minimum ignition energy and air-fuel ratio]

[0074] Next, the relationship between the temperature of the electrode of the spark plug 200, the minimum ignition energy and the air-fuel ratio is determined with reference to Fig. 5 described.

[0075] Fig. Figure 5 is a diagram explaining the relationship between electrode temperature, minimum ignition energy, and air-fuel ratio.

[0076] Fig. Figure 5 shows values ​​of the air-fuel ratios corresponding to the minimum ignition energy. Fig. 5, the up-down direction indicates the voltage scale value corresponding to the minimum ignition energy of the air-fuel mixture, and the left-right direction indicates the air-fuel ratio scale value corresponding to the air-fuel ratio of the air-fuel mixture. Fig. The air-fuel ratio P1 shown in FIG. 5 corresponds to a predetermined value of the minimum ignition energy at which the air-fuel mixture can be ignited in a state where the spark plug electrode temperature is low (for example, -25°C). On the other hand, the air-fuel ratio P2 is a value of the air-fuel ratio corresponding to a predetermined value of the minimum ignition energy at which the air-fuel mixture can be ignited in a state where the spark plug electrode temperature is high (for example, -7°C).

[0077] As in Fig. As shown in Figure 5, in the internal combustion engine 100, as the air-fuel ratio increases (the fuel becomes thinner), the value of the minimum ignition energy of the air-fuel mixture increases, making it less likely that the air-fuel mixture will be ignited by discharge (ignition) from the spark plug. In addition, because the value of the minimum ignition energy of the air-fuel mixture increases as the electrode temperature of the spark plug decreases, it is difficult to ignite the air-fuel mixture by discharge (ignition) from the spark plug.

[0078] For example, it is assumed that a value corresponding to the minimum ignition energy corresponding to the air-fuel ratio P2 in a state where the spark plug electrode temperature is high is obtained in a state where the spark plug electrode temperature is low. In this case, the discharge (ignition) from the spark plug 200 cannot exceed the minimum ignition energy unless the air-fuel ratio is set to the air-fuel ratio P1, which is lower than the air-fuel ratio P2 (the fuel is thick). Therefore, conventionally, as a setting with a safety margin that does not cause problems such as misfire in the internal combustion engine 100, the rich air-fuel ratio is set in the fuel injection control unit 82 under the assumption that the electrode temperature of the spark plug 200 is always low.As a result, the production of hydrocarbons (HC) during combustion in the internal combustion engine 100 increases as the fuel proportion in the air-fuel mixture increases.

[0079] On the other hand, the minimum ignition energy of the air-fuel mixture is lower, the higher the temperature of the electrode of the spark plug 200 is during cold start (see thick arrow in Fig. 5). Therefore, even if the air-fuel ratio is increased (the fuel is diluted), the discharge (ignition) from the spark plug exceeds the minimum ignition energy, and the air-fuel mixture can be ignited. This can reduce the generation of hydrocarbons (HC) in the internal combustion engine 100. Therefore, in the internal combustion engine 100, as described later, the temperature of the electrode of the spark plug 200 is increased during cold start before discharge (ignition). This makes it possible to increase the air-fuel ratio during cold start and suppress the generation of hydrocarbons (HC). [Multiple ignition]

[0080] Next, a multiple ignition with reference to Fig. 6 described.

[0081] Fig. Figure 6 is a discharge waveform example of multiple ignition.

[0082] It is known that in an internal combustion engine, a large amount of hydrocarbons (HC) is generated during cold start-up when the temperature of each part is approximately equal to the outside air temperature. One of the factors that generates hydrocarbons during cold start-up is that the fuel vaporized at the ignition timing decreases due to the low internal cylinder pressure, and the air-fuel ratio of the air-fuel mixture in the cylinder increases (the fuel is diluted). In this case, the required ignition energy increases, and ignition errors and misfires increase, so the proportion of hydrocarbons increases. This means that misfire is the main cause of hydrocarbon generation.

[0083] Such misfires occur when a flame kernel generated by the ignition cannot grow and is extinguished. In order for the flame kernel to grow and misfires to be suppressed, ambient gas must be circulated in a discharge path between the electrodes 210 and 220 of the spark plug 200 (see Fig. 2) and the heat transferred from the flame core to the electrodes 210 and 220 can be reduced. For example, if multiple ignition is performed in the ignition device to preheat the electrodes 210 and 220 of the spark plug 200, the temperature difference between the discharge path and the flame core and the electrodes 210 and 220 is reduced. This can reduce the amount of heat transferred from the discharge path or the flame core to the electrodes 210 and 220.

[0084] As in Fig. 6, by repeating the switching on and off of the ignition signal, multiple ignitions are performed by adding multiple discharge times. This can increase the temperature of the electrodes 210 and 220 of the spark plug 200 before the main ignition of the spark plug 200 (discharge at the ignition timing). The multiple ignition by the additional discharge can be performed at a time that does not overlap the ignition timing of the main ignition. For example, the multiple ignition by the additional discharge can be performed at least in a period from the main ignition to the start of fuel injection (period from the power stroke to the intake stroke in the embodiment of Fig. 6) are carried out. [Temperature and discharge energy of the ignition coil]

[0085] Next, the temperature and discharge energy of the ignition coil 300 are measured with reference to Fig. 7 described.

[0086] Fig. 7 is a conceptual diagram showing a relationship between the supplyable discharge energy and the required discharge energy with respect to the temperature of the ignition coil.

[0087] In Fig. 7, the horizontal axis represents the temperature TC (hereinafter referred to as “ignition coil temperature TC”) of the ignition coil 300 (see Fig. 4) and the vertical axis represents the ignition efficiency indicated by the unit of discharge energy megajoule (mJ). The ignition efficiency includes, for example, the required discharge energy determined according to an operating state of the internal combustion engine 100 based on the above-described minimum ignition energy for igniting the air-fuel mixture, and the deliverable discharge energy serving as an upper limit for making the ignition coil temperature TC less than or equal to the rated temperature. As described above, the required discharge energy is influenced by the air-fuel ratio of the air-fuel mixture, the exhaust gas recirculation amount, and the like. In addition, the deliverable discharge energy usually increases when the ignition coil temperature TC deviates from the rated temperature. If the rated temperature in Fig. 7 is set to 120 °C, for example, when the ignition coil temperature TC decreases to 80 °C and 40 °C below the rated temperature, the value of the deliverable discharge energy increases in accordance with the temperature decrease.

[0088] Because a high current of, for example, approximately 15 A flows through the primary coil 310 of the ignition coil 300 and the igniter 340, the instantaneous heat generation is repeated with each ignition. Therefore, the deliverable discharge energy A is set based on the ignition coil temperature TC, and the energization of the ignition coil 300 is controlled based on the deliverable discharge energy A so that the temperatures of the primary coil 310 of the ignition coil 300 and the igniter 340 do not exceed the predetermined rated temperature (the specified heat-resistant temperature of each component). The discharge energy A that can be delivered by the ignition coil 300 decreases as the ignition coil temperature TC increases and approaches the rated temperature.

[0089] The required discharge energy B is mainly influenced by the condition of the air-fuel mixture near the spark plug electrode, i.e., the air-fuel ratio and the intake flow. The required discharge energy B essentially assumes a minimum value when the air-fuel ratio of the air-fuel mixture is close to the theoretical (stoichiometric) air-fuel ratio. On the other hand, the required discharge energy B increases when the air-fuel ratio deviates from the theoretical air-fuel ratio.

[0090] In general, inclinations of the supplyable discharge energy A and the required discharge energy B with respect to the temperature axis of the ignition coil temperature TC, which is in the left-right direction in Fig. 7 are different. Therefore, as shown in Fig. 7, the supplyable discharge energy A and the required discharge energy B. For example, if the temperature at the point where the two discharge energies A and B intersect is higher than the rated temperature (intended use temperature range) of the ignition coil 300, the ignition coil 300 can always output a discharge energy A that is greater than or equal to the required discharge energy B without exceeding the rated temperature. In this case, the ignition effect of the internal combustion engine 100 is always satisfied without being limited by the temperature of the ignition coil 300.

[0091] On the other hand, when, for example, a lean-burn combustion technique is implemented to improve the vehicle's fuel consumption, in which an air-fuel mixture exceeding the theoretical air-fuel ratio (fuel is thinner) is burned to operate the internal combustion engine, the required discharge energy B increases when the air-fuel ratio of the air-fuel mixture deviates from the theoretical air-fuel ratio. Therefore, the temperature at the point where the two discharge energies A and B intersect may drop below the rated temperature of the ignition coil 300 (within the use temperature range). In this case, it is difficult to continuously supply the required discharge energy amount B exceeding the supplyable discharge energy A at a temperature higher than the intersection temperature of the ignition coil 300.Therefore, the practical applicability of a so-called fuel consumption improvement technique such as lean combustion and exhaust gas recirculation of the internal combustion engine 100 is limited by the lack of supplyable discharge energy A at a temperature higher than the temperature point where the two discharge energies A and B intersect.

[0092] Hereinafter, a difference value between the deliverable discharge energy A and the required discharge energy B, when the deliverable discharge energy A is lower than the required discharge energy B, is defined as ignition efficiency insufficiency C. [Relationship between the temperature of the conventional ignition coil and the discharge energy]

[0093] Next, the relationship between the temperature of the conventional ignition coil and the discharge energy is examined with reference to Fig. 8 described.

[0094] Fig. Figure 8 is a conceptual diagram showing a relationship between temperature and discharge energy of a conventional ignition coil.

[0095] The horizontal axis of the Fig. The graph shown in Figure 8 represents the ignition coil temperature TC, and the vertical axis represents the ignition efficiency. In addition, a thick line in Fig. 8 shows the discharge energy output by the conventional ignition coil. As shown in Fig. 8, in the prior art ignition device (see, for example, JP 2000-054941 A), because the value of the ignition coil temperature TC is not clear, for example, when 120°C is used as the nominal temperature in Fig. 8, an inputtable discharge energy A2 at 120°C is always used as the initial limit value of the discharge energy of the ignition coil. This means that in the conventional ignition device, the inputtable discharge energy A2 remains substantially unchanged even when the ignition coil temperature TC changes. In other words, the conventional ignition device is designed so that the temperature at the point where the inputtable discharge energy A2 and the required discharge energy B intersect is higher than the rated temperature of the ignition coil in a case where ignition is performed in a state where the air-fuel ratio is close to the theoretical air-fuel ratio.Therefore, the ignition effect of the internal combustion engine 100 to which the conventional ignition device is applied is always satisfied without being influenced by the temperature of the ignition coil 300, at least under the condition that the ignition is carried out in a state where the air-fuel ratio is close to the theoretical air-fuel ratio.

[0096] However, when lean combustion or exhaust gas recirculation is performed, in which a portion of the burned exhaust gas is taken in and recirculated, the required discharge energy B is higher than in a case where the air-fuel mixture is ignited in a state close to the theoretical air-fuel mixture as described above, so that the temperature at the point where the two discharge energies A and B intersect is below the rated temperature. In this case, at a temperature higher than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect, the ignition efficiency insufficiency C increases in accordance with the increase in the ignition coil temperature TC, so that the possibility of misfire occurs.Under these circumstances, in the internal combustion engine to which the conventional ignition device is applied, a restriction is imposed so that the lean combustion and the exhaust gas recirculation are carried out only in a low load situation in which the amount of air flowing into the cylinder is reduced and the required discharge energy B is reduced. [Relationship between the temperature of the ignition coil and the discharge energy according to the present invention]

[0097] Next, the relationship between the temperature of the ignition coil and the discharge energy according to the present invention will be described with reference to Fig. 9 described.

[0098] Fig. 9 is a conceptual diagram of a relationship between the temperature of an ignition coil and the discharge energy in a case where the present invention is applied.

[0099] The horizontal axis of the Fig. The graph shown in Figure 9 represents the ignition coil temperature TC, and the vertical axis represents the ignition efficiency. In addition, a thick line in Fig. 9 the discharge energy output by the ignition coil 300. As shown in Fig. 9, according to the present embodiment, the supplyable discharge energy A is prioritized over the required discharge energy B when the temperature of the ignition coil 300 becomes higher than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect each other.

[0100] That is, according to the present embodiment, when the ignition coil temperature TC becomes higher than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect, the discharge energy of the ignition coil 300 is set to the supplyable discharge energy A. Thereby, when the discharge energy of the ignition coil 300 becomes higher than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect, the discharge energy is gradually reduced as the ignition coil temperature TC increases.

[0101] Note that, according to the present embodiment, at a temperature higher than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect, the fuel injection amount can be increased so that ignition occurs in a state where the air-fuel ratio is close to the theoretical air-fuel ratio, and the value of the required discharge energy B can be significantly reduced. That is, according to the present embodiment, the ignition quality of the air-fuel mixture is improved to compensate for insufficient ignition efficiency by reducing the discharge energy. Thereby, the required ignition efficiency can be achieved while reducing the value of the required discharge energy B to prevent overheating of the ignition coil 300. As a result, misfires can be suppressed.According to the present embodiment, the value of the required discharge energy B can be made higher than that of the conventional ignition device to perform lean combustion and exhaust gas recirculation at a lower temperature than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect. Therefore, even in a high-load situation where the required discharge energy B is maximized by increasing the amount of air flowing into the cylinder or the like, leaner combustion and exhaust gas recirculation can be performed than in the conventional ignition device, while preventing both misfire and overheating of the ignition coil 300. This can improve the fuel consumption of the vehicle.

[0102] As described above, according to the present embodiment, the discharge energy of the ignition coil 300 is changed according to the temperature of the ignition coil 300. Therefore, the temperature of the ignition coil 300 (the temperature of the ignition device) needs to be detected. The temperature of the ignition coil 300 can be detected, for example, by providing a temperature sensor.

[0103] However, if the temperature sensor is provided in the ignition coil 300, the cost increases with the added sensing element and wiring, or the housing size increases. Therefore, according to the present embodiment, the temperature of the ignition coil 300 is estimated without providing a temperature sensor. This makes it possible to prevent cost increases and the housing size increase while suppressing misfires. [Ignition and fuel injection control processing]

[0104] Next, the processing of the ignition and fuel injection control according to the first embodiment will be described with reference to Fig. 10 described.

[0105] Fig. 10 is a flowchart showing the processing of the ignition and fuel injection control according to the first embodiment.

[0106] Ignition and fuel injection control processing is initiated with the start of the internal combustion engine 100 (engine start). First, the overall control unit 81 detects the supply voltage VB (S1). Subsequently, the overall control unit 81 detects the rotational speed NE of the internal combustion engine 100 (S2). Next, the ignition timing setting unit 811 of the overall control unit 81 sets the ignition timing of the internal combustion engine 100 according to the rotational speed NE (S3).

[0107] Next, the overall control unit 81 sets explanatory variables of the neural network model (S4). According to the present embodiment, a plurality of explanatory variables are set in advance by detection, estimation, or calculation from various parameter groups, including the temperature of the ignition coil 300 and the operating state of the internal combustion engine 100, with respect to the parameter related to the thermal balance inside and outside the ignition device.

[0108] Next, the ignition device temperature estimation unit 814 of the overall control unit 81 inputs an explanatory variable into the first neural network model and estimates a temperature value (ignition coil temperature) TC related to the ignition device (S5). The explanatory variables input to the first neural network model include at least the supply voltage VB and the rotational speed NE.

[0109] Next, the setting unit 813 of the overall control unit 81 inputs the explanatory variable into the second neural network model and outputs the limit excitation time corresponding to the ignition coil temperature TC (S6). The explanatory variables input to the second neural network model include at least the supply voltage VB, the rotational speed NE, and the ignition coil temperature TC.

[0110] The limit excitation time is an upper limit of the time during which the current is supplied to the ignition coil 300 (primary coil 310), and it corresponds to the above-described supplyable discharge energy A. Therefore, the limit excitation time can also be referred to as the limit excitation intensity.

[0111] Next, the requirement setting unit 812 of the overall control unit 81 inputs an explanatory variable into the third neural network model and outputs a required excitation time according to the operating state of the internal combustion engine 100 (S7). The explanatory variables input into the third neural network model include at least the supply voltage VB and the rotational speed NE.

[0112] The required excitation time is the time during which a current must be supplied to the ignition coil 300 (the primary coil 310) to satisfy the required discharge energy B. Therefore, the required excitation time can also be referred to as the required excitation intensity.

[0113] Next, the setting unit 813 of the overall control unit 81 determines whether the required energization time is longer than the limit energization time (S8). If it is determined in step S8 that the required energization time is not longer than the limit energization time (NO in S8), the setting unit 813 sets the required energization time as the energization time of the ignition coil 300 (hereinafter referred to as "ignition coil energization time") (S9).

[0114] On the other hand, if it is determined in step S8 that the required energization time exceeds the limit energization time (YES in S8), the setting unit 813 sets the limit energization time as the ignition coil energization time (S10).

[0115] After the processing of step S9 or S10, the fuel injection amount setting unit 815 of the overall control unit 81 sets the target air-fuel ratio of the fuel injection control unit 82 to a stoichiometric value corresponding to the ignition coil temperature TC (S11). When the ignition efficiency is deteriorated in the processing of step S11, for example, by setting the limit energization time to the ignition coil energization time, a value of a target air-fuel ratio related to a determination of a fuel injection amount Tinj in the fuel injection control unit 82 is set to the theoretical air-fuel ratio at which the required discharge energy B assumes the minimum value or a value close to the theoretical air-fuel ratio, as described above with respect to the ignition coil temperature TC.This makes it possible to reduce the value of the minimum ignition energy of the air-fuel mixture (the required discharge energy B can be reduced), thereby suppressing misfires.

[0116] Next, the fuel injection control unit 82 causes the fuel injector 134 to perform fuel injection (S12). Specifically, the fuel injection control unit 82 supplies the fuel injection amount Tinj to the fuel injector 134 based on the target air-fuel ratio set in step S11 and the drive current (drive voltage) corresponding to the fuel injection timing set by the fuel injection timing setting unit.

[0117] Next, the ignition control unit 83 causes the ignition device to perform ignition (S13). Specifically, the ignition control unit 83 outputs the ignition signal SA corresponding to the ignition coil energization time set in steps S9 and S10, the ignition timing IGADV set in step S3, and the rotational speed NE to the ignition coil 300. After the processing of step S13, the overall control unit 81 returns the processing to step S1. [Neural network model]

[0118] Next, the neural network model according to the present embodiment will be described with reference to Fig. 11, Fig. 12 and Fig. 13 described.

[0119] Fig. 11 is a conceptual diagram showing the weight and bias of each neuron constituting each neural network model such as a first neural network model with the ignition coil temperature TC as the target variable, a second neural network model with the limit excitation time as the target variable, and a third neural network model with the required excitation time as the target variable. Fig. 12 is a diagram for explaining a method of realizing the operation of each target variable by the neural network model according to the present embodiment. Fig. 13 is a conceptual diagram showing a neural network model used for the ignition and fuel injection control processing according to the first embodiment.

[0120] The neural network model is a mathematical model that simulates the mechanism of a human cranial nerve circuit. According to the present embodiment, the neural network model is a multi-layer neural network model with an input layer into which the explanatory variable is input, an output layer that outputs a target variable, and an intermediate layer that connects the input layer and the output layer. The neural network model is often used as a means for performing deep learning in so-called machine learning. For example, an error feedback method can be applied to a machine learning algorithm.It should be noted that although a neural network model is used according to the present embodiment, the present invention is not limited to this example as long as the estimation of the ignition coil temperature TC and the limit energization time and the required energization time can be determined by machine learning.

[0121] As in Fig. As shown in Figure 11, a weight w and a bias b are set for each neuron (each unit) constituting the neural network model. Inputs a1 through an are each input to n neurons, and they are multiplied by weights w1 through wn set for the respective neurons. Then, the inputs multiplied by the weights w1 through wn are added (combined) in the neurons in the next layer, and the output z is obtained, in which the bias b is added to the addition result. The neuron in the next layer outputs a, which is represented by a function f(z).

[0122] In addition, a function called the activation function is defined for each neuron. A logistic function (sigmoid function), a ramp function (rectified linear unit (ReLU) function), and the like are appropriately defined for the activation function. Fig. Figure 11 shows an example where the larger the input x is and the farther it is from 0, the more the neuron is activated and the closer the output y (= f(x)) is to 1, and the smaller the input x is and the farther it is from 0, the more the neuron is deactivated and the closer it is to 0. For example, if the input x is "5", the output y of the activation function is "1", and "1" is output from the neuron to the neuron in the next layer.

[0123] As in Fig. As shown in Figure 12, the intermediate layer of the multilayer neural network model is designed to superimpose multiple layers formed by multiple neurons. By forming a large neural network model with a high number of neurons and a high number of intermediate layers, a complex input / output relationship can be learned and the accuracy of approximating the target variable can be increased. However, there is a trade-off between increasing the accuracy of approximation and the size of the neural network.Therefore, the neural network model of the control device of the internal combustion engine of the vehicle according to the present embodiment is designed and provided after previously considering a so-called cost-effective compatibility point in which a balance is formed between the desired accuracy of approximation and the requirement for the model size, taking into account the computation processing capability of the control device 1, the package size, cost reductions, and the like.

[0124] Furthermore, the input / output relationship of the neural network model can be approximated with high accuracy by setting a variable having a causal relationship with the target variable in the input layer as training data of the explanatory variable, setting the target variable in the output layer as training data, and then performing machine learning (supervised learning) on ​​the weight w and bias b for multiple neurons in the intermediate layer using a well-known algorithm such as an error feedback method. In the learned model subjected to such learning, when the explanatory variable used for machine learning as training data is input to the input layer, the input / output relationship calculation is performed based on the learned content, and the value of the target variable based on the input explanatory variable is output as the calculation result.

[0125] A neural network model of the ignition and fuel injection control processing according to the first embodiment of the present invention will be described with reference to Fig. 10 and Fig. 13 described.

[0126] Fig. Figure 13 shows an input / output relationship for both an explanatory variable and a target variable between several neural network models in processing the ignition and fuel injection control according to the Fig. 10. Note that, in addition to the first, second, and third neural network models used in the processing of steps S5, S6, and S7 described above, the ignition and fuel injection control processing according to the present embodiment may be configured to use the fourth neural network model for fuel injection control in step S12 and an estimation algorithm using the fifth neural network model for ignition control in step S13.

[0127] According to the present embodiment, first, a plurality of explanatory variables including the supply voltage VB and the rotational speed NE, which have a causal relationship with the ignition coil temperature TC, are input to the input layer of the trained first neural network model with the ignition coil temperature TC as a target variable, and the ignition coil temperature TC is output from the output layer through the calculation processing in the intermediate layer as described above (step S5).Next, several explanatory variables, including the supply voltage VB and the rotational speed NE, which have a causal relationship with the limit excitation time, and the ignition coil temperature TC output from the above-described first neural network model are input to the input layer of the trained second neural network model with the limit excitation time of the ignition coil 300 as the target variable, and the limit excitation time is output from the output layer (step S6) through the calculation processing in the intermediate layer.Further, several explanatory variables, including the supply voltage VB and the rotational speed NE, which have a causal relationship with the required excitation time, are input to the input layer of the trained third neural network using the required excitation time as the target variable, and the required excitation time is output from the output layer through the calculation processing in the intermediate layer (step S7). Subsequently, the limit excitation time output by the second neural network model and the required excitation time output by the third neural network model are set in the comparison calculation of the requirement setting unit 812 (step S8), and the ignition coil excitation time is set based on the result of the comparison between the limit excitation time and the required excitation time (steps S8, S9, and S10).

[0128] Next, a plurality of explanatory variables, including the fuel injection amount corresponding to the target air-fuel ratio (step S11), corresponding to the supply voltage VB, the rotational speed NE, and the ignition coil temperature TC, which have a causal relationship with the opening / closing time of the fuel injection valve, are input to the input layer of the trained fourth neural network model using the opening / closing time of the fuel injection valve as a target variable, and the opening / closing time of the fuel injection valve is output from the output layer according to the crank angle measured by the angle information generation unit 85 through the calculation processing in the intermediate layer (step S12).Subsequently, several explanatory variables, including the rotational speed NE, the ignition timing IGADV, and the ignition coil energization time, which have a causal relationship with the ignition signal SA, are input to the input layer of the trained fifth neural network model using the energization instruction for the ignition coil, that is, the ignition signal SA output to the igniter 340, as a target variable, and the ignition signal SA corresponding to the crank angle measured by the angle information generation unit 85 is output from the output layer through the calculation processing in the intermediate layer (step S13). As shown in FIG. Fig. 13, the Fig. 10, the ignition and fuel injection control processing according to the first embodiment may be configured using the first to fifth neural network models. [Relationship between the target variable and the explanatory variable]

[0129] Next, a relationship between the target variable and the explanatory variable according to the present embodiment will be described with reference to Fig. 14 described.

[0130] Fig. 14 is a correspondence table showing a relationship between target variables and explanatory variables of the first to fifth neural network models according to the first embodiment. An example of an explanatory variable input for estimating (calculating) each target variable is shown.

[0131] As in Fig. 14, when estimating the ignition coil temperature TC as a target variable in the first neural network model, in addition to the rotational speed NE and the supply voltage VB as described above, a variable selected from the intake flow rate, the intake pressure, the intake temperature, the intake humidity, rainfall (rainfall detection), the cooling water temperature, a value related to the cooling wind speed, the traveling speed of the vehicle, the ignition timing, the ignition coil energization time (execution value), the number of energizations / one energization cycle, the elapsed time after the engine (internal combustion engine) starts, the elapsed time after the engine (internal combustion engine) stops, and the supplyable discharge energy (previously calculated value) is input into the first neural network model as an explanatory variable, and machine learning is performed for a plurality of neurons in the intermediate layer.

[0132] It should be noted that, in addition to the explanatory variables described above, explanatory variables that can be further added to the first neural network model may include, for example, the combustion pressure detected by the in-cylinder pressure sensor, the lubricating oil temperature, a value related to the crank angle at which each intake valve / exhaust valve of the internal combustion engine is opened or the crank angle at which each valve is closed, the accelerator pedal opening degree, the ignition coil temperature TC (previous value), the ignition coil energization time, the air-fuel ratio feedback correction coefficient, the voltage of the downstream air-fuel ratio sensor (O2 sensor), the voltage of the upstream air-fuel ratio sensor (linear air-fuel ratio sensor), a value,relating to a property (octane number or the like) of the fuel supplied to the internal combustion engine, the operating state of a cooling fan, the torque, the intake amount, the fuel injection amount, the air-fuel ratio or an equivalent ratio, the value of the pressure in the exhaust pipe related to exhaust gas recirculation, and the like. Some or all of these are selected in consideration of the magnitude of a causal relationship with the ignition coil temperature TC as the target variable, the size of the neural network model as described above, the ease of detecting the variables in the control device, and the like, and the required variables can be set as explanatory variables of the first neural network model. [Explanatory variable]

[0133] Next, a method for selecting an explanatory variable for estimating the ignition coil temperature TC with reference to Fig. 15 described.

[0134] Fig. 15 is a table showing an example of variables related to an influencing factor taken into account when selecting an explanatory variable for estimating the ignition coil temperature TC according to the first embodiment.

[0135] The influencing factors related to the fluctuation of the ignition coil temperature TC include a factor related to the internal heat generation of the ignition coil and a factor related to the external heat transfer. The magnitude of the absolute value of the correlation coefficient with the ignition coil temperature TC is determined for each Fig. 15 is taken into account. Then, the variables are selected, for example, in descending order of the correlation coefficient as explanatory variables of the first neural network model.

[0136] The internal heat generation of the ignition coil includes heat generation by the secondary current, heat generation by the primary current and heat generation in the ignition device 340 (see Fig. 4). This heat generation occurs due to power loss in the internal circuit of the ignition coil. Therefore, for each internal heat generation, a variable with a large correlation coefficient is selected as the explanatory variable. Examples of variables that have a high correlation coefficient with heat generation by the secondary current include the rotational speed NE, the intake flow rate, the intake pressure, the air-fuel ratio of the mixed gas, the ignition timing, and the ignition coil energization time / number of energizations / cycle. Examples of variables that have a high correlation coefficient with the primary current and heat generation by the ignition device include the rotational speed NE, the supply voltage VB, and the ignition coil energization time / number of energizations / cycle.

[0137] The external heat transfer of the ignition coil occurs at a contact portion located outside the housing of the ignition coil 300. The objects in direct contact with the ignition coil 300 include, for example, the air (atmosphere), a spark plug, and a cylinder head in an ignition coil of a type in which an ignition coil is arranged adjacent to a spark plug for each cylinder of the internal combustion engine 1. Therefore, a variable with a large correlation coefficient for each object in direct contact with the ignition coil 300 is selected as an explanatory variable.For example, variables that have a high correlation coefficient with external heat transfer include intake air temperature, intake air humidity, rainfall amount, cooling water temperature, lubricating oil temperature, cooling wind speed, vehicle running speed, air-fuel ratio of the gas mixture, number of cylinders, time elapsed after the engine (internal combustion engine) starts, and time elapsed after the engine (internal combustion engine) stops.

[0138] According to the present embodiment, an example has been described in which the required excitation intensity and the limit excitation time in a case where sparks are generated by discharge (ignition) to ignite the air-fuel mixture are determined, and the excitation intensity of the ignition coil is adjusted. The discharge (ignition) is performed intermittently for one combustion cycle of the internal combustion engine 100 (one ignition for each compression top dead center every two revolutions of the crank), or the discharge and ignition are performed for each compression top dead center and each exhaust dead center. In addition, the present invention can be applied to a case where an additional discharge in the spark plug is performed multiple times in addition to the ignition at top dead center (a case where the multiple ignition described above is performed).That is, based on the total required excitation intensity and the limit excitation time for one combustion cycle of the internal combustion engine 100, the respective ignition coil excitation intensities at compression top dead center ignition can be individually set for each rotary ignition or multiple ignition. For example, if the ignition coil excitation time at compression top dead center is set based on the required excitation intensity, and each ignition coil excitation time at exhaust top dead center discharge or multiple ignition discharge can be set by dividing and calculating a value obtained by subtracting the required excitation intensity from the total limit excitation time for one combustion cycle of the internal combustion engine 100 according to the scheduled number of exhaust top dead center discharges or multiple ignition discharges.Furthermore, the discharge at the exhaust top dead center or the discharge by multiple ignition is carried out at a lower temperature than the temperature at the point where the supplyable discharge energy A and the required discharge energy B intersect, as shown in . Fig. 9 shown, executed. < Second embodiment >

[0139] An internal combustion engine control device according to a second embodiment will be described below. The internal combustion engine control device according to the second embodiment differs from the internal combustion engine control device according to the first embodiment in terms of the ignition and fuel injection control processing. Therefore, the ignition and fuel injection control processing of the internal combustion engine control device according to the second embodiment will be described here, and the description of the common configuration will be omitted.

[0140] A ROM 60 of the internal combustion engine control device according to the second embodiment stores a limit residence time map used when calculating a limit excitation intensity (supplyable discharge energy A), a request residence time map used when calculating a requested excitation intensity (required discharge energy B), and a voltage correction coefficient map. [Border stay card]

[0141] The border residence time card stored in ROM 60 is updated with reference to Fig. 16 described.

[0142] Fig. Figure 16 is a diagram explaining the border retention time map.

[0143] The X-axis from Fig. 16 represents the rotational speed NE, and the Y-axis from Fig. 16 represents the ignition coil temperature TC. The Z-axis from Fig. 16 represents the excitation threshold time. The excitation threshold time is a variable representing the excitation threshold strength (supplyable discharge energy A) as the time for supplying current to the ignition coil 300 (primary coil 310).

[0144] The limit dwell time map consists of map data in a list format, whereby a plurality of limit energization times are defined by associating a plurality of index values ​​(e.g., 40, 80, 120°C) related to a plurality of ignition coil temperatures TC and a plurality of index values ​​(e.g., the idle rotation speed IDLE, 3000, 7000 rpm) related to a plurality of rotation speeds NE. The setting unit 813 according to the second embodiment calculates the limit energization time corresponding to the value of the ignition coil temperature TC and the value of the rotation speed NE based on the value defined in the limit dwell time map. Note that, according to the present embodiment, as represented by a linear line, the points of a plurality of index values ​​in Fig. 16, when the value of the ignition coil temperature TC and the value of the rotational speed NE correspond to values ​​located between several index values, the limit excitation time can be calculated by performing a linear interpolation calculation, thereby connecting points of several index values ​​located close to each other. [Request Dwell Time Card]

[0145] The request dwell time map stored in ROM 60 is updated with reference to Fig. 17 described.

[0146] Fig. Figure 17 is a diagram explaining the request dwell time map.

[0147] The horizontal axis of the Fig. 17 represents the rotational speed NE, and the vertical axis of the graph shown in Fig. The graph shown in Figure 17 represents the card excitation time. The card excitation time is a variable used when calculating a required excitation time, described later.

[0148] The request dwell time map consists of map data in a table format, whereby a plurality of map energization times are defined by associating a plurality of index values ​​(e.g., the idle rotation speed IDLE, 3000, 7000 rpm) related to a plurality of rotation speeds NE. The request setting unit 812 according to the second embodiment calculates a map energization time corresponding to the value of the rotation speed NE based on the value defined in the request dwell time map. [Voltage correction coefficient map]

[0149] The voltage correction coefficient map stored in the ROM 60 is calculated with reference to Fig. 18 described.

[0150] Fig. Figure 18 is a diagram explaining the voltage correction coefficient map.

[0151] The horizontal axis of the Fig. 18 represents the supply voltage VB, and the vertical axis of the graph shown in Fig. The graph shown in Figure 18 represents the voltage correction coefficient. The voltage correction coefficient is a coefficient used when calculating a required excitation time, which will be described later.

[0152] The voltage correction coefficient map consists of map data in a table format, whereby multiple voltage correction coefficients are defined by associating multiple index values ​​(e.g., 5, 12, 14 V, 16 V) related to multiple supply voltages VB. According to the second embodiment, the voltage correction coefficient corresponding to the value of the rotational speed NE is calculated based on the value defined in the voltage correction coefficient map.

[0153] The requirement setting unit 812 according to the second embodiment calculates the required excitation time (required excitation intensity) by multiplying the map excitation time by the voltage correction coefficient. The required excitation time is a variable representing the required excitation intensity (required discharge energy B) as the time for supplying current to the ignition coil 300 (primary coil 310). That is, because the current consumption in the ignition coil 300 greatly affects the internal heat generation of the ignition coil, which in turn affects the ignition coil temperature TC, the required excitation time is set according to the value of the supply voltage VB related to the current consumption. [Ignition and fuel injection control processing]

[0154] Next, the processing of the ignition and fuel injection control according to the second embodiment will be described with reference to Fig. 19 described.

[0155] Fig. 19 is a flowchart showing the processing of the ignition and fuel injection control according to the second embodiment.

[0156] Steps S21 to S25 of the ignition and fuel injection control processing according to the second embodiment are similar to steps S1 to S5 of the ignition and fuel injection control processing according to the first embodiment. Therefore, the description of steps S21 to S25 is omitted.

[0157] After the processing of step S25, the setting unit 813 of the overall control unit 81 determines the limit excitation time (limit excitation intensity) according to the rotation speed NE and the ignition coil temperature TC using the limit residence time map (see Fig. 16) (S26).

[0158] Next, the request setting unit 812 of the overall control unit 81 determines a map energization time corresponding to the rotation speed NE using the request dwell time map (see Fig. 17) (S27). Next, the requirement setting unit 812 determines a voltage correction coefficient corresponding to the supply voltage VB using the voltage correction coefficient map (S28). Then, the requirement setting unit 812 calculates the required excitation time (required excitation strength) by multiplying the map excitation time by the voltage correction coefficient (S29).

[0159] Next, the setting unit 813 of the overall control unit 81 determines whether the card energization time exceeds the limit energization time (S30). If it is determined in step S30 that the card energization time does not exceed the limit energization time (NO in S30), the setting unit 813 sets the required energization time (the value obtained by multiplying the card energization time by the voltage correction coefficient) as the ignition coil energization time (S31).

[0160] On the other hand, if it is determined in step S30 that the required energization time exceeds the limit energization time (YES in S30), the setting unit 813 sets a value (limit energization intensity) obtained by multiplying the voltage correction coefficient by the limit energization time as the ignition coil energization time (S32).

[0161] Steps S33 to S35 of the ignition and fuel injection control processing according to the second embodiment are similar to steps S11 to S13 of the ignition and fuel injection control processing according to the first embodiment. Therefore, the description of steps S33 to S35 is omitted. < Third embodiment >

[0162] An internal combustion engine control device according to a third embodiment will be described below. The internal combustion engine control device according to the third embodiment differs from the internal combustion engine control devices according to the first embodiment and the second embodiment in terms of the ignition and fuel injection control processing. Therefore, the ignition and fuel injection control processing of the internal combustion engine control device according to the third embodiment will be described here, and the description of the common configuration will be omitted.

[0163] The ROM 60 of the internal combustion engine control device according to the third embodiment stores a request dwell time map, a voltage correction coefficient map, and a temperature correction coefficient map, which are used when executing the ignition and fuel injection control processing. The request dwell time map and the voltage correction coefficient map are similar to the request dwell time map (see Fig. 17) and the voltage correction coefficient map (see Fig. 18) of the second embodiment. [Temperature correction coefficient map]

[0164] The temperature correction coefficient map stored in ROM 60 is calculated with reference to Fig. 20 described.

[0165] Fig. Figure 20 is a diagram explaining the temperature correction coefficient map.

[0166] The horizontal axis of the Fig. 20 represents the ignition coil temperature TC, and the vertical axis of the graph shown in Fig. The graph shown in Figure 18 represents the temperature correction coefficient. The temperature correction coefficient is used when calculating the ignition coil excitation time described later.

[0167] The temperature correction coefficient map consists of map data in a table format, whereby a plurality of temperature correction coefficients are defined by associating a plurality of index values ​​(e.g., -40, 0, 40, 80, 120°C) related to a plurality of ignition coil temperatures TC. The setting unit 813 according to the third embodiment calculates a temperature correction coefficient corresponding to the value of the ignition coil temperature TC based on the value defined in the temperature correction coefficient map.

[0168] According to the third embodiment, the ignition coil energization time is calculated by multiplying the required energization time (required energization intensity) calculated by the requirement setting unit 812 by the temperature correction coefficient. That is, the ignition coil energization time is adjusted according to the temperature correction coefficient based on the ignition coil temperature TC. [Ignition and fuel injection control processing]

[0169] Next, the processing of the ignition and fuel injection control according to the third embodiment will be described with reference to Fig. 21 described.

[0170] Fig. 21 is a flowchart showing the processing of the ignition and fuel injection control according to the third embodiment.

[0171] Steps S41 to S45 of the ignition and fuel injection control processing according to the third embodiment are similar to steps S1 to S5 of the ignition and fuel injection control processing according to the first embodiment. Therefore, the description of steps S41 to S45 is omitted.

[0172] After the processing of step S45, the request setting unit 812 of the overall control unit 81 determines a map excitation time (map excitation strength) corresponding to the rotation speed NE using the request dwell time map (see Fig. 17) (p46).

[0173] Next, the setting unit 813 of the overall control unit 81 determines a temperature correction coefficient corresponding to the ignition coil temperature TC using the temperature correction coefficient map (see Fig. 20) (S47). Next, the request setting unit 812 determines a voltage correction coefficient corresponding to the supply voltage VB using the voltage correction coefficient map (S48). After the processing of step S48, the processing proceeds to step S49, and the request setting unit 812 calculates the required energization time by multiplying the map energization time by the voltage correction coefficient. The required energization time is supplied to the setting unit 813. The setting unit 813 calculates the ignition coil energization time by multiplying the required energization time by the temperature correction coefficient (S49).

[0174] Steps S50 to S52 of the ignition and fuel injection control processing according to the third embodiment are similar to steps S11 to S13 of the ignition and fuel injection control processing according to the first embodiment. Therefore, the description of steps S50 to S52 is omitted.

[0175] It should be noted that in the request setting unit 812 of both the second and third embodiments, the time determined using the request residence time map in Fig. 17 is multiplied by the voltage correction coefficient to determine the required excitation time (S29, S49). However, the calculation of the required excitation time according to the present invention is not limited to this. For example, the required dwell time map may use a map of a configuration (not shown) that defines a plurality of required excitation times (required excitation strengths) by associating a plurality of index values ​​related to a plurality of rotational speeds NE and a plurality of index values ​​related to a plurality of supply voltages VB. In this case, the above-described voltage correction coefficient map ( Fig. 18) and the multiplication of the card excitation strength by the voltage correction coefficient can be omitted. < Fourth Embodiment >

[0176] An internal combustion engine control device according to a fourth embodiment will be described below. The internal combustion engine control device according to the fourth embodiment differs from the internal combustion engine control devices according to the first to third embodiments in terms of the ignition and fuel injection control processing. Therefore, the ignition and fuel injection control processing of the internal combustion engine control device according to the fourth embodiment will be described here, and the description of the common configuration will be omitted.

[0177] The ROM 60 of the internal combustion engine control device according to the fourth embodiment stores a low-temperature request dwell time map, a high-temperature request dwell time map, and a voltage correction coefficient map to be used in executing the ignition and fuel injection control processing. The voltage correction coefficient map is similar to the voltage correction coefficient map according to the second embodiment (see Fig. 18). [Low temperature demand residence time map]

[0178] The low temperature demand residence time map stored in ROM 60 is updated with reference to Fig. 22 described.

[0179] Fig. Figure 22 is a diagram explaining the low temperature demand residence time map.

[0180] The horizontal axis of the Fig. 22 represents the rotational speed NE, and the vertical axis of the graph shown in Fig. The graph shown in Figure 22 represents the low-temperature map excitation time. As described later, the low-temperature map excitation time (low-temperature map excitation intensity) is used when calculating the low-temperature ignition coil excitation time used in a case where the ignition coil temperature TC falls below a predetermined low-temperature set value. The low-temperature ignition coil excitation time is also used when calculating the ignition coil excitation time in a case where the ignition coil temperature TC is between a preset high-temperature set value and a preset low-temperature set value.

[0181] The low-temperature demand dwell time map defines a plurality of low-temperature map excitation times (low-temperature map excitation strengths) by associating a plurality of index values ​​related to a plurality of rotation speed NE values ​​(e.g., the idle rotation speed IDLE, 3000, 7000 rpm). The demand setting unit 812 according to the fourth embodiment calculates the low-temperature map excitation time corresponding to the rotation speed NE value based on the value defined in the low-temperature demand dwell time map. [High temperature demand residence time map]

[0182] The high temperature demand residence time map stored in ROM 60 is updated with reference to Fig. 23 described.

[0183] Fig. Figure 23 is a diagram explaining the high temperature demand residence time map.

[0184] The horizontal axis of the Fig. 23 represents the rotational speed NE, and the vertical axis of the graph shown in Fig. The graph shown in Figure 23 represents the high-temperature map excitation time. As described later, the high-temperature map excitation time (high-temperature map excitation intensity) is used when calculating the high-temperature ignition coil excitation time in a case where the ignition coil temperature TC exceeds a predetermined high-temperature set value. In addition, the high-temperature ignition coil excitation time is also used when calculating the ignition coil excitation time in a case where the ignition coil temperature TC is between a preset high-temperature set value and a preset low-temperature set value.

[0185] The high-temperature demand dwell time map defines a plurality of high-temperature map energization times by associating a plurality of index values ​​(e.g., the idle rotation speed IDLE, 3000, 7000 rpm) related to a plurality of rotation speed values ​​NE. The demand setting unit 812 according to the fourth embodiment calculates the high-temperature map energization time corresponding to the rotation speed value NE based on the value defined in the high-temperature demand dwell time map. [Ignition and fuel injection control processing]

[0186] Next, the processing of the ignition and fuel injection control according to the fourth embodiment will be described with reference to Fig. 24 described.

[0187] Fig. 24 is a flowchart showing the processing of the ignition and fuel injection control according to the fourth embodiment.

[0188] Steps 61 to 65 of the ignition and fuel injection control processing according to the fourth embodiment are similar to steps S1 to S5 of the ignition and fuel injection control processing according to the first embodiment. Therefore, the description of steps S61 to S65 is omitted.

[0189] After the processing of step S65, the request setting unit 812 of the overall control unit 81 determines the low-temperature map excitation time (low-temperature map excitation intensity) corresponding to the rotation speed NE using the low-temperature request dwell time map (S66). Next, the request setting unit 812 determines the high-temperature map excitation time (high-temperature map excitation intensity) corresponding to the value of the rotation speed NE using the high-temperature request dwell time map (S67).

[0190] Next, the setting unit 813 of the overall control unit 81 determines a voltage correction coefficient corresponding to the value of the supply voltage VB using the voltage correction coefficient map (S68). Then, the setting unit 813 determines whether the ignition coil temperature TC exceeds a predetermined low-temperature set value (S69).

[0191] If it is determined in step S69 that the ignition coil temperature TC does not exceed the predetermined low temperature set value (NO in S69), the setting unit 813 sets the temperature change determination flag to “0” (S70).

[0192] If it is determined in step S69 that the ignition coil temperature TC exceeds the predetermined low temperature set value (YES in S69), the setting unit 813 determines whether the ignition coil temperature TC is below the predetermined high temperature set value (S71).

[0193] If it is determined in step S71 that the ignition coil temperature TC is lower than the predetermined high-temperature set value (YES in S71), the setting unit 813 determines whether the temperature change determination flag is set to "1" (S72). Note that the high-temperature set value exceeds the low-temperature set value.

[0194] If it is determined in step S72 that the temperature change detection flag is not "1" (NO in S72), the setting unit 813 executes the processing of step S73 described later.

[0195] If it is determined in step S72 that the temperature change detection flag is “1” (YES in step S72), the setting unit 813 executes the processing of step S75 described later.

[0196] After the processing of step S70 or in a case where NO is determined in step S72, the setting unit 813 calculates the ignition coil energization time (ignition coil energization strength) by multiplying the low-temperature map energization time by the voltage correction coefficient (S73).

[0197] On the other hand, when it is determined in step S71 that the ignition coil temperature TC does not fall below the predetermined high temperature target value (NO in S71), the setting unit 813 sets the temperature change determination flag to “1” (S74).

[0198] After the processing of step S74 or in a case where step S72 is YES, the setting unit 813 calculates the ignition coil energization time by multiplying the high-temperature map energization time by the voltage correction coefficient (S75).

[0199] Steps S76 to S78 of the ignition and fuel injection control processing according to the fourth embodiment are similar to steps S11 to S13 of the ignition and fuel injection control processing according to the first embodiment. Therefore, the description of steps S76 to S78 is omitted.

[0200] As described above, the low temperature demand residence time map (see Fig. 22) and the high temperature demand residence time map (see Fig. 23) According to the fourth embodiment, the low-temperature map excitation time and the high-temperature map excitation time (map excitation intensity) correspond to the value of the rotational speed NE. However, the low-temperature request dwell time map and the high-temperature request dwell time map according to the fourth embodiment may define the requested excitation time (required excitation intensity) according to both the value of the rotational speed NE and the value of the supply voltage VB.

[0201] In this case, the ignition coil energization time (ignition coil energization intensity) for the low temperature is determined using the low-temperature request dwell time map (corresponding to S73) or the ignition coil energization time (ignition coil energization intensity) for the high temperature is determined using the high-temperature request dwell time map (corresponding to S75). Note that in this case, the calculation of the voltage correction coefficient (S68) and the multiplication by the voltage correction coefficient in steps S73 and S75 can be omitted.

[0202] According to the fourth embodiment described above, the low-temperature map energization time and the high-temperature map energization time are switched using the low-temperature set value and the high-temperature set value, and the ignition coil energization time is set to change gradually in the temperature direction. However, when the ignition coil temperature TC is between the low-temperature set value and the high-temperature set value, the setting unit 813 according to the present invention can determine the ignition coil energization time by performing an interpolation calculation of a value between the low-temperature map energization time and the high-temperature map energization time. That is, the ignition coil energization time can be set by interpolation calculation from the low-temperature set value to the high-temperature set value so that the shape of its slope changes. < Fifth Embodiment >

[0203] An internal combustion engine control device according to a fifth embodiment will be described below. The internal combustion engine control device according to the fifth embodiment has a similar configuration to the internal combustion engine control device according to the first embodiment. The internal combustion engine control device according to the fifth embodiment differs from the internal combustion engine control device according to the first embodiment in an electrical circuit including an ignition coil. Therefore, an electrical circuit including an ignition coil of the internal combustion engine control device according to the fifth embodiment will be described here, and description of a common configuration will be omitted. [Electrical circuit containing the ignition coil]

[0204] The electrical circuit including the ignition coil according to the fifth embodiment will be described with reference to Fig. 25 described.

[0205] Fig. 25 is a diagram for explaining the electric circuit including the ignition coil according to the fifth embodiment.

[0206] One in Fig. The electrical circuit 501 shown in Figure 25 includes an ignition coil 301. The ignition coil 301 includes a primary coil 310 having a predetermined number of turns and a secondary coil 320 having a greater number of turns than the primary coil 310. The primary coil 310 and the secondary coil 320 are similar to those shown in Figure 25. Fig. 5 shown first embodiment.

[0207] The other end of the primary coil 310 is connected to a drain (D) terminal of an igniter (excitation control circuit) 340 and grounded via the igniter 340. A gate (G) terminal of the igniter 340 is connected to the ignition control unit 83 via a temperature switching unit 360.

[0208] The temperature switching unit 360 is installed to prevent damage due to overheating of the ignition coil 301. The temperature switching unit 360 includes a temperature detection unit 361. The temperature detection unit 361 detects the temperature of the ignition coil 301 through the ignition device 340. When the temperature detected by the temperature detection unit 361 becomes greater than or equal to a predetermined threshold value A (first temperature), the temperature switching unit 360 interrupts the ignition signal SA output from the ignition control unit 83 to the ignition device 340.

[0209] An operating state of the temperature switching unit 360 corresponding to the threshold A (first temperature) is input to the overall control unit 81 (not shown). Therefore, according to the fifth embodiment, the overall control unit 81 can read the ignition coil temperature TC as the first temperature based on the operating state of the temperature switching unit 360. As described above, the internal combustion engine control device according to the present invention is not limited to the one that estimates the ignition coil temperature TC, and may include a temperature detection unit that detects the ignition coil temperature TC. [Summary]

[0210] (1) The above-described control device 1 (internal combustion engine control device) according to the first embodiment controls the internal combustion engine 100 by interrupting the current flowing through the ignition coil 300 of the ignition device with a predetermined ignition timing. The control device 1 includes the request setting unit 812, the setting unit 813, and the ignition control unit 83. The request setting unit 812 determines a required excitation intensity (required excitation time) of the ignition coil 300 based on the rotational speed NE of the internal combustion engine 100. The setting unit 813 sets the ignition coil excitation time (excitation intensity of the ignition coil) according to the ignition coil temperature TC (the temperature relative to the ignition device) and the required excitation intensity. The ignition control unit 83 controls the interruption state of the ignition coil 300 according to the ignition coil energization time set by the setting unit 813.

[0211] This allows the thermal balance of the ignition device of the ignition coil 300 to be appropriately controlled. This can prevent an increase in the size and cost of the ignition device.

[0212] (2) The ROM 60 (storage unit) according to the second embodiment described above stores the request dwell time map, the limit dwell time map, and the voltage correction coefficient map. The request dwell time map defines the relationship between the rotational speed NE and the map excitation strength. The limit dwell time map defines the relationship between the rotational speed NE and the ignition coil temperature TC (the temperature related to the ignition device) and the limit excitation strength, which is an excitation strength that can be applied to the ignition coil. The voltage correction coefficient map defines the relationship between the ignition device supply voltage VB and the voltage correction coefficient.The request setting unit 812 determines the map excitation intensity corresponding to the rotational speed NE using the request dwell time map and determines the voltage correction coefficient corresponding to the supply voltage using the voltage correction coefficient map. Then, the request setting unit 812 calculates the requested excitation intensity by multiplying the map excitation intensity by the voltage correction coefficient. The setting unit 813 determines the limit excitation intensity according to the rotational speed NE and the ignition coil temperature TC using the limit dwell time map. Then, the setting unit 813 sets the ignition coil excitation time (the excitation intensity of the ignition coil) based on the requested excitation intensity when the requested excitation intensity is less than or equal to the limit excitation intensity.On the other hand, if the required excitation intensity is greater than the limit excitation intensity, the ignition coil excitation time is determined based on the limit excitation intensity.

[0213] This allows the ignition coil excitation time to be easily adjusted according to the ignition coil temperature TC and the required excitation strength.

[0214] (3) The ROM 60 (storage unit) according to the above-described third embodiment stores the request dwell time map, the voltage correction coefficient map, and the temperature correction coefficient map. The request dwell time map defines the relationship between the rotational speed NE and the map excitation strength. The voltage correction coefficient map defines the relationship between the ignition device supply voltage VB and the voltage correction coefficient. The temperature correction coefficient map defines the relationship between the ignition coil temperature TC (temperature with respect to the ignition device) and the temperature correction coefficient. The request setting unit 812 determines the map excitation strength according to the rotational speed NE using the request dwell time map.The voltage correction coefficient corresponding to the supply voltage VB is determined using the voltage correction coefficient map, and the temperature correction coefficient corresponding to the ignition coil temperature TC is determined using the temperature correction coefficient map. Then, the setting unit 813 calculates the ignition coil excitation time (ignition coil excitation strength) by multiplying the map excitation strength by the voltage correction coefficient and the temperature correction coefficient.

[0215] This allows the ignition coil excitation time to be easily adjusted according to the ignition coil temperature TC and the required excitation strength.

[0216] (4) The ROM 60 (storage unit) according to the fourth embodiment described above stores the low-temperature demand dwell time map, the high-temperature demand dwell time map, and the voltage correction coefficient map. The low-temperature demand dwell time map defines the relationship between the rotation speed and the low-temperature map excitation strength. The high-temperature demand dwell time map defines the relationship between the rotation speed and the high-temperature map excitation strength. The voltage correction coefficient map defines the relationship between the igniter supply voltage VB and the voltage correction coefficient.The request setting unit 812 determines the low-temperature map energization time corresponding to the rotation speed NE using the low-temperature request dwell time map, and the high-temperature map energization time corresponding to the rotation speed NE using the high-temperature request dwell time map. The setting unit 813 sets the ignition coil energization time (ignition coil energization intensity) based on the low-temperature map energization time and the high-temperature map energization time according to the ignition coil temperature TC (temperature relative to the ignition device).

[0217] This allows the ignition coil excitation time to be easily adjusted according to the ignition coil temperature TC and the required excitation strength.

[0218] (5) The setting unit 813 according to the fourth embodiment described above sets the ignition coil energization time (ignition coil energization intensity) based on the low-temperature map energization time (low-temperature map energization intensity) if the ignition coil temperature TC (the temperature relative to the ignition device) falls below a predetermined low-temperature set value. In addition, if the ignition coil temperature TC exceeds a predetermined high-temperature set value that is greater than the low-temperature set value, the setting unit 813 sets the ignition coil energization time based on the high-temperature map energization time (high-temperature map energization intensity).Furthermore, in a case where the ignition coil temperature TC is between the low-temperature set point and the high-temperature set point, if the ignition coil temperature TC changes from a state lower than or equal to the low-temperature set point to the high-temperature set point, the setting unit 813 sets the ignition coil energization time based on the low-temperature map energization time. If the ignition coil temperature TC changes from a state higher than or equal to the high-temperature set point to the low-temperature set point, the ignition coil energization time is set based on the high-temperature map energization time.

[0219] This allows the hysteresis control to be executed in a case where the ignition coil temperature TC is between the low temperature set value and the high temperature set value to determine the ignition coil energization time.

[0220] (6) The ignition coil energization time (ignition coil energization intensity) according to the above-described embodiment is obtained by summarizing the substantial energization times of the ignition coil 300, wherein a single ignition is performed for each compression top dead center, two ignitions are performed for each compression and exhaust top dead center, and multiple discharge (multiple ignition / discharge) is interrupted at points other than the top dead center for one combustion cycle of the internal combustion engine 100.

[0221] This allows the ignition coil excitation time (ignition coil excitation intensity) set according to the ignition coil temperature TC and the required excitation intensity to be easily adjusted to be applied to multiple types of discharge (ignition) systems.

[0222] (7) The internal combustion engine according to the above-described embodiment includes the fuel injection device 134. The control device 1 (internal combustion engine control device) includes the fuel injection amount setting unit 815, which sets the fuel injection amount in the fuel injection device 134 based on the ignition coil temperature TC (temperature relative to the ignition device). By increasing the ignition quality of the air-fuel mixture by adjusting the fuel injection amount, the required excitation intensity can be reduced.

[0223] This allows the ignition coil excitation time to be easily adjusted according to the ignition coil temperature TC and the required excitation intensity. In addition, misfires can be suppressed.

[0224] (8) The ignition coil temperature TC (temperature with respect to the ignition device) according to the first to fourth embodiments described above is calculated using a neural network model having at least the rotational speed NE as an explanatory variable.

[0225] This allows the ignition coil temperature TC to be estimated with high accuracy without providing a temperature sensor that detects the temperature of the ignition coil 300. This can increase the accuracy of the ignition coil energization time to be set according to the ignition coil temperature TC, and appropriately control the thermal balance of the ignition device. This can reduce the cost of the ignition device.

[0226] (9) The explanatory variables input to the neural network models according to the first to fourth embodiments described above include a parameter (the rotational speed NE, the supply voltage VB, the ignition coil excitation strength, etc.) related to the heat generation of the ignition coil 300 in the ignition device, and a parameter (intake air temperature, intake air humidity, cooling water temperature, cooling wind speed, and the like) related to the heat balance inside and outside the ignition device.

[0227] This allows the ignition coil temperature TC to be estimated with high accuracy.

[0228] (10) The internal combustion engine control method according to the above-described embodiment is a method for controlling the internal combustion engine 100 in which the current flowing through the ignition coil 300 of the ignition device is interrupted with a predetermined ignition timing. In this internal combustion engine control method, the request setting unit 812 determines the requested excitation intensity of the ignition coil 300 based on the rotational speed NE of the internal combustion engine 100. Next, the setting unit 813 sets the ignition coil excitation time (excitation intensity of the ignition coil) according to the ignition coil temperature TC (the temperature with respect to the ignition device) and the requested excitation intensity. Then, the ignition control unit 83 controls the interruption state of the ignition coil 300 according to the ignition coil excitation time set by the setting unit 813.

[0229] This allows the thermal balance of the ignition device to be appropriately controlled and can prevent an increase in the size and cost of the ignition device.

[0230] (11) In the internal combustion engine control method according to the first embodiment described above, the ignition device temperature estimation unit 814 outputs the ignition coil temperature TC (temperature related to the ignition device) using the first neural network model that has at least the rotational speed NE of the internal combustion engine 100 as an explanatory variable. The setting unit 813 outputs the limit excitation time (limit excitation intensity), which is an excitation intensity that can be applied to the ignition coil 300, using the second neural network model that has the ignition coil temperature TC, the power supply voltage VB, and the rotational speed NE as explanatory variables.The request setting unit 812 outputs the requested excitation time (required excitation intensity) of the ignition coil 300 using the third neural network model, which includes at least the rotational speed NE and the ignition coil temperature TC as explanatory variables. In addition, the setting unit 813 sets the ignition coil excitation time (ignition coil excitation intensity) based on the limit excitation time and the requested excitation time. Then, the ignition control unit controls the cutoff state of the ignition coil 300 according to the ignition coil excitation time set by the setting unit 813.

[0231] This allows the ignition coil temperature TC to be determined without providing a temperature sensor that detects the temperature of the ignition coil 300. This allows the cost of the ignition device to be reduced. In addition, the accuracy of the ignition coil temperature TC, the limit energization time, and the required energization time can be improved, the reliability of the set ignition coil energization time can be improved, and the thermal balance of the ignition device can be appropriately controlled.

[0232] (12) The explanatory variable of the first neural network model or the explanatory variable of the third neural network model according to the first embodiment described above includes a parameter (rotation speed NE, supply voltage VB, intake flow rate, etc.) related to the heat generation of the ignition coil 300 in the ignition device, and a parameter (intake air temperature, intake air humidity, cooling water temperature, cooling wind speed, and the like) related to the heat balance inside and outside the ignition device.

[0233] This allows the ignition coil temperature TC to be estimated with high accuracy.

[0234] The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications may be made without departing from the spirit of the invention described in the claims.

[0235] In addition, the above embodiments have been described in detail to make the present invention easy to understand, and they are not necessarily limited to having all of the described configurations. Furthermore, part of the configuration of one embodiment may be replaced with the configuration of another embodiment, and the configuration of another embodiment may be added to the configuration of one embodiment. In addition, other configurations may be added to, subtracted from, and replaced with part of the configuration of each embodiment. List of reference symbols 1 combustion engine control device 10 Analog input unit 20 Digital input unit 30 A / D converters 40 RAM 50 MPU 60 ROM 70 I / O ports 80 output circuit 81 Total control unit 82 Fuel injection control unit 83 Ignition control unit 84 Cylinder discrimination unit 85 Angle information generation unit 86 Rotational speed information generation unit 87 Inlet flow measuring unit 88 Load information generation unit 89 Water temperature measuring unit 90 voltage measuring unit 100 combustion engine 110 air purifiers 111 Intake pipe 112 intake manifold 113 throttle valve 113a Throttle opening sensor 114 Flow rate sensor 115 Intake air temperature sensor 120 ring gear 121 Crank angle sensor 122 Water temperature sensor 123 Crankshaft 125 accelerator pedal 126 Accelerator pedal position sensor 130 fuel tank 131 Fuel pump 132 pressure regulators 133 Fuel line 134 Fuel injection device 140 cylinder pressure sensor 150 cylinders 151 Inlet valve 152 exhaust valve 160 exhaust manifold 161 Three-way catalyst 162 upstream air-fuel ratio sensor 163 downstream air-fuel ratio sensor 170 pistons 200 spark plug 210 middle electrode 220 outer electrode 230 Insulator 300, 301 ignition coil 310 Primary coil 320 secondary coil 330 DC power supply 340 ignition device 350, 360 temperature switching unit 361 Temperature recording unit 500, 501 electrical circuit 811 Ignition timing unit 812 Requirements definition unit 813 setting unit 814 Ignition device temperature estimation unit 815 Fuel injection quantity determination unit 816 Fuel injection timing setting unit QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2000-054941 A [0005, 0095]

Claims

[1] An internal combustion engine control device that controls an internal combustion engine by interrupting a current flowing through an ignition coil of an ignition device according to a predetermined ignition timing, the internal combustion engine control device comprising: a requirement setting unit that determines a required excitation strength of the ignition coil based on the rotational speed of the internal combustion engine, an adjusting unit which adjusts the excitation strength of the ignition coil according to the temperature relating to the ignition device and the required excitation strength, and an ignition control unit that controls an interruption state of the ignition coil according to the excitation strength of the ignition coil set by the setting unit. [2] An internal combustion engine control device according to claim 1, further comprising a storage unit that stores a request dwell time map defining a relationship between the rotational speed and a map excitation intensity, and a limit dwell time map defining a relationship between a temperature related to the rotational speed and the ignition device and a limit excitation intensity, which is an excitation intensity that can be applied to the ignition coil, wherein the requirement setting unit calculates the required excitation intensity according to the rotation speed using the requirement dwell time map, the setting unit determines a limit excitation intensity corresponding to the rotational speed and the temperature with respect to the ignition device using the limit residence time map and sets the excitation intensity of the ignition coil based on the required excitation intensity if the required excitation intensity is less than or equal to the limit excitation intensity, and the excitation strength of the ignition coil is determined on the basis of the limit excitation strength if the required excitation strength is greater than the limit excitation strength. [3] An internal combustion engine control device according to claim 1, further comprising a storage unit that stores a request dwell time map defining a relationship between the rotational speed and a map excitation strength, a voltage correction coefficient map defining a relationship between the supply voltage of the ignition device and a voltage correction coefficient, and a temperature correction coefficient map defining a relationship between the temperature and a temperature correction coefficient with respect to the ignition device, wherein the request setting unit determines a map excitation strength corresponding to the rotation speed using the request dwell time map, determines a voltage correction coefficient corresponding to the supply voltage using the voltage correction coefficient map and determines a temperature correction coefficient corresponding to the temperature with respect to the ignition device using the temperature correction coefficient map and the setting unit calculates the excitation strength of the ignition coil by multiplying the card excitation strength by the voltage correction coefficient and the temperature correction coefficient. [4] The internal combustion engine control device according to claim 1, further comprising a storage unit that stores a low-temperature request dwell time map defining a relationship between the rotational speed and a low-temperature map excitation strength, a high-temperature request dwell time map defining a relationship between the rotational speed and a high-temperature map excitation strength, and a voltage correction coefficient map defining a relationship between the supply voltage of the ignition device and a voltage correction coefficient, wherein the requirement setting unit determines a low-temperature map excitation strength corresponding to the rotational speed using the low-temperature requirement residence time map and determines a high-temperature map excitation strength corresponding to the rotational speed using the high-temperature requirement residence time map, and the setting unit sets the excitation strength of the ignition coil based on a temperature related to the ignition device, the low-temperature map excitation strength and the high-temperature map excitation strength. [5] The internal combustion engine control device according to claim 4, wherein the setting unit sets the excitation intensity of the ignition coil based on the low-temperature map excitation intensity if the temperature with respect to the ignition device is less than or equal to a predetermined low-temperature set value, and sets the excitation intensity of the ignition coil based on the high-temperature map excitation intensity if the temperature with respect to the ignition device is greater than or equal to a predetermined high-temperature set value which is higher than the low-temperature set value. [6] An internal combustion engine control apparatus according to claim 1, wherein the excitation strength of the ignition coil is obtained by aggregating a substantial excitation time to the ignition coil which is interrupted once or more times during one combustion cycle of the internal combustion engine. [7] An internal combustion engine control device according to claim 1, wherein the internal combustion engine has a fuel injection device, and a fuel injection amount setting unit that sets the fuel injection amount in the fuel injection device based on the temperature related to the ignition device. [8] An internal combustion engine control apparatus according to claim 1, wherein the temperature related to the ignition device is output using a neural network model having at least the rotational speed as an explanatory variable. [9] An internal combustion engine control apparatus according to claim 8, wherein an explanatory variable input to the neural network model includes a parameter related to heat generation of the ignition coil in the ignition device and a parameter related to heat balance inside and outside the ignition device. [10] An internal combustion engine control method for controlling an internal combustion engine by interrupting a current flowing through an ignition coil of an ignition device in accordance with a predetermined ignition timing, the method comprising: Determining a required excitation strength of the ignition coil based on the rotational speed of the internal combustion engine by a requirement setting unit, Setting an excitation strength of the ignition coil according to the temperature related to the ignition device and the required excitation strength by means of an adjusting unit and Controlling the interruption state of the ignition coil according to the excitation strength of the ignition coil set by the setting unit by an ignition control unit. [11] An internal combustion engine control method for controlling an internal combustion engine by interrupting a current flowing through an ignition coil of an ignition device in accordance with a predetermined ignition timing, the method comprising: Outputting a temperature related to the ignition device using a first neural network model having at least the supply voltage of the ignition device and the rotational speed of the internal combustion engine as explanatory variables by an ignition device temperature estimation unit, Outputting a limit excitation intensity, which is an excitation intensity that can be applied to the ignition coil, using a second neural network model having the temperature related to the ignition device, the supply voltage and the rotational speed as explanatory variables, by a setting unit, Outputting a required excitation intensity of the ignition coil using a third neural network model having at least the rotational speed and the temperature related to the ignition device as explanatory variables by a requirement setting unit, Adjusting the excitation strength of the ignition coil based on the limit excitation strength and the required excitation strength by the adjusting unit and Controlling the interruption state of the ignition coil according to the excitation strength of the ignition coil set by the setting unit by an ignition control unit. [12] The internal combustion engine control method according to claim 11, wherein the explanatory variable of the first neural network model or the explanatory variable of the third neural network model includes a parameter related to heat generation of the ignition coil in the ignition device and a parameter related to heat balance inside and outside the ignition device.

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