Control device for internal combustion engines

Abstract

To suppress the occurrence of pre-ignition during restart. [Solution] Intermittent stopping is performed in the internal combustion engine 10. The control device 100 has a processing circuit 110. The processing circuit 110 performs a determination process to determine whether or not there is a high probability of pre-ignition occurring when the internal combustion engine 10 is restarted after intermittent stopping. Furthermore, if the determination process determines that there is a high probability of pre-ignition occurring, the processing circuit 110 performs a reduction process to lower the cranking speed, which is the rotational speed of the crankshaft 18 of the internal combustion engine 10 during cranking performed at restart, compared to when it is determined that there is no high probability of pre-ignition occurring.

Description

[Technical Field]

[0001] The present invention relates to a control device for an internal combustion engine. [Background Art]

[0002] For example, as described in Patent Document 1, an internal combustion engine that performs intermittent stop and restart is known. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2010-168966 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] At the time of restart after intermittent stop, the temperature inside the cylinder is higher than that at the time of cold start. When the temperature inside the cylinder is high, the compression end temperature, which is the temperature inside the cylinder at compression top dead center, tends to increase, so pre-ignition is likely to occur. Therefore, it is desired to suppress the occurrence of pre-ignition during restart. [Means for Solving the Problem]

[0005] A control device for an internal combustion engine that solves the above problem is a control device for an internal combustion engine in which intermittent stop is performed, and includes a processing circuit. The processing circuit performs: a determination process of determining whether there is a possibility that pre-ignition occurs when restarting the internal combustion engine after the intermittent stop; and a reduction process of, when it is determined in the determination process that the possibility of pre-ignition occurring is high, reducing a cranking rotation speed that is a rotation speed of a crankshaft of the internal combustion engine during cranking performed at the time of the restart, as compared with a case where it is determined that the possibility of pre-ignition occurring is not high. [Effect of the Invention]

[0006] This internal combustion engine control system can suppress the occurrence of pre-ignition during restart. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the configuration of an internal combustion engine in one embodiment. [Figure 2] Figure 2 is a flowchart showing the processing steps performed by the processing circuit of this embodiment. [Figure 3] Figure 3 is a flowchart showing the processing steps performed by the processing circuit of this embodiment. [Figure 4] Figure 4 is a time chart showing the change in cranking speed when the internal combustion engine of the same embodiment is restarted. [Modes for carrying out the invention]

[0008] The following describes one embodiment of a control device for an internal combustion engine installed in a vehicle. <Configuration of an internal combustion engine> As shown in Figure 1, the internal combustion engine 10 includes a cylinder block 11, a cylinder head 12, and a head cover 13, among other components.

[0009] The cylinder block 11 contains cylinders 16, which constitute the cylinders of the internal combustion engine 10. A piston 15 is disposed inside each cylinder 16. The cylinder head 12 is provided with an intake port 30 for introducing intake air into the combustion chamber 17 of the internal combustion engine 10, and an exhaust port 70 for discharging exhaust gas from the combustion chamber 17.

[0010] An intake valve 81 is provided in the intake port 30. The drive system for this intake valve 81 is provided with an intake-side variable valve timing mechanism 85, which is a variable valve timing mechanism that changes the valve timing of the intake valve 81, namely the opening and closing times.

[0011] An exhaust valve 82 is provided in the exhaust port 70. The drive system for this exhaust valve 82 is provided with an exhaust-side variable valve timing mechanism 86, which is a variable valve timing mechanism that changes the valve timing of the exhaust valve 82, namely the opening and closing times.

[0012] The internal combustion engine 10 is equipped with fuel injectors that supply fuel into the cylinders. Specifically, the internal combustion engine 10 is equipped with a port injector 83 that injects fuel into the intake port 30 and an in-cylinder injector 84 that directly injects fuel into the combustion chamber 17. In addition, a spark plug 23 is provided in the cylinder head 12.

[0013] A crankcase 19 is provided at the lower part of the cylinder block 11, which houses the crankshaft 18, the output shaft of the internal combustion engine 10. An intake passage 20 is connected upstream of the intake port 30. The intake passage 20 is equipped with a throttle valve 28 for adjusting the amount of intake air.

[0014] An exhaust passage 90 is connected downstream of the exhaust port 70. The crankshaft 18 is mechanically connected to the carrier C of the planetary gear mechanism 300, which constitutes the power split device.

[0015] The sun gear S of the planetary gear mechanism 300 is mechanically connected to the rotating shaft 310a of the first motor generator 310. The first motor generator 310 functions as a generator that generates electricity using engine output, and also functions as a starting starter that cranks the crankshaft 18 when starting the internal combustion engine 10.

[0016] The ring gear R of the planetary gear mechanism 300 is mechanically connected to the rotating shaft 320a of the second motor generator 320 and the drive wheel 400. The second motor generator 320 functions as an electric motor that generates driving force for the drive wheels 400, and also functions as a generator that generates electricity through regeneration when the vehicle is decelerating.

[0017] An AC voltage is applied to a terminal of the first motor generator 310 by an inverter 330. Further, an AC voltage is applied to a terminal of the second motor generator 320 by an inverter 340. As described above, the internal combustion engine 10 of the present embodiment is an internal combustion engine for a vehicle equipped with a hybrid system including the internal combustion engine 10 and a motor generator as prime movers.

[0018] The control device 100 operates various operation target devices such as a throttle valve 28, a port injection valve 83, a cylinder injection valve 84, an ignition plug 23, an intake-side variable valve mechanism 85, and an exhaust-side variable valve mechanism 86. Further, the control device 100 operates the inverter 330 to control the first motor generator 310. Furthermore, the control device 100 operates the inverter 340 to control the second motor generator 320.

[0019] The control device 100 includes a processing circuit 110. The processing circuit 110 includes a CPU that executes processing according to a program, and a ROM that stores the program. Various types of control are implemented when the CPU executes the program stored in the ROM.

[0020] Although not shown in the drawings, the control device 100 is composed of a plurality of control units, including a control unit for the internal combustion engine and a control unit for the first motor generator 310 and the second motor generator 320.

[0021] The control device 100 receives detection signals from various sensors. For example, the control device 100 receives a detection signal from the air flow meter 51, which detects the intake air volume GA. The control device 100 also receives a detection signal from the accelerator pedal operation amount sensor 52, which detects the accelerator pedal operation amount ACCP, which is the amount of operation of the accelerator pedal that adjusts the output of the internal combustion engine 10. The control device 100 also receives a detection signal from the intake air temperature sensor 53, which detects the intake air temperature THA. The control device 100 also receives a detection signal from the water temperature sensor 57, which detects the coolant temperature THW, which is the temperature of the coolant of the internal combustion engine 10. The control device 100 also receives a detection signal from the crank angle sensor 50, which detects the rotation angle (crank angle) of the crankshaft 18 in order to calculate the engine rotation speed NE, and a detection signal from the vehicle speed sensor 56, which detects the vehicle speed SP of the vehicle equipped with the internal combustion engine 10. The control device 100 also receives a detection signal from the intake side cam angle sensor 58, which detects the intake side valve timing VTin, which is the valve timing of the intake valve 81. Furthermore, the control device 100 receives a detection signal from the exhaust-side cam angle sensor 59, which detects the exhaust-side valve timing VTex, which is the valve timing of the exhaust valve 82. The control device 100 also receives an output signal Sm1 from the first rotation angle sensor 350, which detects the rotation angle of the first motor generator 310. Furthermore, the control device 100 receives an output signal Sm2 from the second rotation angle sensor 360, which detects the rotation angle of the second motor generator 320.

[0022] The control device 100 calculates the engine load ratio KL based on the engine rotational speed NE and the intake air volume GA. The engine load ratio KL is a parameter that determines the amount of air filled into the combustion chamber 17, and is the ratio of the amount of air inflow per combustion cycle per cylinder to the standard amount of incoming air. The standard amount of incoming air is set variably according to the engine rotational speed NE.

[0023] The control device 100 calculates the required torque for the vehicle's operation based on the accelerator pedal input (ACCP) and vehicle speed (SP). The control device 100 then controls the required output Pe of the internal combustion engine 10 and the output torques of the first motor generator 310 and the second motor generator 320 to meet the vehicle's required torque. For example, if the required output Pe of the internal combustion engine 10 is "0", the control device 100 stops the operation of the internal combustion engine 10 and performs EV driving, using the output torque of the second motor generator 320 to drive the vehicle. If the required output Pe of the internal combustion engine 10 is greater than "0", the control device 100 operates the internal combustion engine 10 to obtain engine output and performs hybrid driving, using that engine output and the output torque of the second motor generator 320 to drive the vehicle. In this way, the internal combustion engine 10 repeatedly performs intermittent stopping and restarting.

[0024] The control device 100 calculates the intake-side target value VTint, which is the target valve timing for the intake valve 81, based on the engine rotational speed NE and the engine load ratio KL. Once this intake-side target value VTint is calculated, the control device 100 controls the drive of the intake-side variable valve timing mechanism 85 so that the intake-side valve timing VTint matches the intake-side target value VTint. In this embodiment, the initial value "0" is set to the state where the valve timing of the intake valve 81 is at its most retarded timing, and the valve timing of the intake valve 81 is controlled using the amount of advance of the valve timing from this initial value.

[0025] The control device 100 calculates the exhaust-side target value VText, which is the target valve timing for the exhaust valve 82, based on the engine rotational speed NE and the engine load ratio KL. Once this exhaust-side target value VText is calculated, the control device 100 controls the drive of the exhaust-side variable valve timing mechanism 86 so that the exhaust-side valve timing VTex matches the exhaust-side target value VText. In this embodiment, the initial value "0" is set to the state where the valve timing of the exhaust valve 82 is at its most advanced timing, and the valve timing of the exhaust valve 82 is controlled using the amount of valve timing retardation from this initial value.

[0026] The control device 100 switches between three types of fuel injection modes according to the engine operating state. One of the fuel injection modes that can be switched in this embodiment is a port injection mode in which fuel is injected only from the port injection valve 83. Another fuel injection mode that can be switched in this embodiment is an in-cylinder injection mode in which fuel is injected only from the in-cylinder injection valve 84. And a third fuel injection mode that can be switched in this embodiment is a dual injection mode in which fuel is injected from both the in-cylinder injection valve 84 and the port injection valve 83.

[0027] The switching of the fuel injection mode described above is performed by changing various injection ratios Rp, which represent the ratio of the amount of fuel injected from the port injection valve 83 to the amount of fuel injected from the in-cylinder injection valve 84, within the fuel injection amount Q set based on the engine operating state.

[0028] The injection ratio Rp is variably set within the range of "0 ≤ Rp ≤ 1" based on engine conditions such as engine load ratio KL, engine rotational speed NE, and coolant temperature THW. The value obtained by multiplying the fuel injection amount Q by the injection ratio Rp is set as the port injection amount Qp, which is the amount of fuel injected from the port injection valve 83. On the other hand, the value obtained by subtracting the injection ratio Rp from "1" is calculated as the injection ratio Rd, which represents the ratio of the amount of fuel injected from the in-cylinder injection valve 84 to the total fuel injection amount Q (Rd = 1 - Rp). The value obtained by multiplying the fuel injection amount Q by the injection ratio Rd is set as the in-cylinder injection amount Qd, which is the amount of fuel injected from the in-cylinder injection valve 84.

[0029] <Regarding the process to suppress the occurrence of preignition> When restarting after an intermittent stop, the temperature inside the cylinders of the internal combustion engine 10 is higher than during a cold start. When the temperature inside the cylinders is high, the compression end temperature, which is the temperature inside the cylinder at top dead center of compression, tends to be high. Therefore, pre-ignition is more likely to occur when restarting after an intermittent stop.

[0030] Therefore, in this embodiment, a score is calculated based on a relationship value that is related to the likelihood of pre-ignition occurring. If the calculated score is above a predetermined threshold, it is determined that there is a high probability of pre-ignition occurring, and cranking to suppress pre-ignition is performed.

[0031] Here, the values ​​that are related to the likelihood of pre-ignition occurring include values ​​related to the compression end temperature during cranking and values ​​related to whether or not there is fuel that induces pre-ignition during restart.

[0032] Values ​​that influence the compression end temperature include the coolant temperature THW, the intermittent stop time Ts, the intake air temperature THA, the actual compression ratio of the internal combustion engine 10, and the injection ratio Rp. In other words, the higher the coolant temperature THW during restart, the higher the temperature inside the cylinder, which increases the likelihood of pre-ignition occurring.

[0033] Furthermore, the shorter the intermittent stop time Ts (the time during which the engine is stopped before restarting), the higher the temperature inside the cylinder, which increases the likelihood of pre-ignition occurring. Furthermore, the higher the intake air temperature (THA) during restart, the higher the temperature inside the cylinder, which increases the likelihood of pre-ignition occurring.

[0034] Furthermore, the higher the actual compression ratio of the internal combustion engine 10, the higher the compression end temperature, which increases the likelihood of pre-ignition occurring. The actual compression ratio of the internal combustion engine is determined from the mechanical compression ratio, which is obtained from the stroke length of the piston 15, and the valve timing of the intake valve 81, which is set during restart.

[0035] Furthermore, the larger the injection ratio Rp, the less fuel is injected from the in-cylinder injection valve 84. When the amount of fuel injected from the in-cylinder injection valve 84 decreases, the cooling effect inside the cylinder due to the latent heat of vaporization of the fuel injected from the in-cylinder injection valve 84 decreases, which increases the likelihood of pre-ignition occurring.

[0036] On the other hand, the degree of deterioration of the port injectors 83 and in-cylinder injectors 84 over time is a factor that influences whether or not there is fuel present that induces pre-ignition during restart. In other words, as the degree of deterioration of the port injectors 83 and in-cylinder injectors 84 over time increases, the amount of fuel that leaks from these fuel injectors during intermittent stopping may increase. Therefore, as the degree of deterioration of the port injectors 83 and in-cylinder injectors 84 over time increases, the likelihood of pre-ignition occurring increases.

[0037] Another value that influences whether or not there is fuel that induces pre-ignition during restart is the fuel octane number of the internal combustion engine 10. In other words, the lower the fuel octane number, the higher the likelihood of pre-ignition occurring.

[0038] Based on these factors, the following are considered to be related to the likelihood of pre-ignition occurring: coolant temperature THW, intermittent stop time Ts, intake air temperature THA, actual compression ratio, injection ratio Rp, the degree of deterioration of the port injectors 83 and in-cylinder injectors 84 over time, and fuel octane rating.

[0039] Therefore, in this embodiment, as an example, the score is calculated based on the coolant temperature THW, the intermittent stop time Ts, and the intake air temperature THA. Figure 2 shows the procedure for calculating the score. This process is performed by the processing circuit 110 at predetermined execution cycles. In the following, the step number of each process is represented by a number preceded by "S".

[0040] In the series of processes shown in Figure 2, the processing circuit 110 determines whether or not there is a restart request after the intermittent stop (S100). If it is determined that there is a request to restart after an intermittent stop (S100: YES), the processing circuit 110 obtains the coolant temperature THW, the intermittent stop time Ts, and the intake air temperature THA (S110).

[0041] Next, the processing circuit 110 calculates a first score S1 based on the cooling water temperature THW and the intermittent stop time Ts (S120). In the process of S120, the processing circuit 110 calculates the first score S1 such that the value of the first score S1 increases as the cooling water temperature THW increases.

[0042] Furthermore, the processing circuit 110 calculates the first score S1 such that the value of the first score S1 increases as the intermittent stop time Ts decreases. Therefore, the value of the first score S1 increases as the likelihood of pre-ignition occurring during restart increases.

[0043] Next, the processing circuit 110 calculates a second score S2 based on the intake air temperature THA (S130). In the process of S130, the processing circuit 110 calculates the second score S2 such that the value of the second score S2 increases as the intake air temperature THA increases. Therefore, the higher the probability of pre-ignition occurring during restart, the higher the value of the second score S2.

[0044] Next, the processing circuit 110 calculates the total score St by calculating the sum of the first score S1 and the second score S2 and substituting the calculated value into the total score St (S140).

[0045] Then, if the process in S140 is executed, or if a negative determination is made in the process in S100, the processing circuit 110 terminates this process. Figure 3 shows the procedure performed by the processing circuit 110. This procedure is executed when the calculation of the total score St described above is completed.

[0046] In the series of processes shown in Figure 3, the processing circuit 110 obtains the calculated total score St (S200). Next, the processing circuit 110 performs a determination process to determine whether or not there is a high probability of a pre-ignition occurring during restart (S210). In the process of S210, the processing circuit 110 determines that there is a high probability of a pre-ignition occurring during restart if the acquired total score St is equal to or greater than a predetermined threshold Stref. The threshold Stref is pre-set in magnitude so that it can accurately determine whether there is a high probability of a pre-ignition occurring based on whether the total score St is equal to or greater than the threshold Stref.

[0047] In the process of S210, if it is determined that there is a high probability that pre-ignition will occur during restart (S210: YES), the processing circuit 110 performs cranking to suppress pre-ignition (S220).

[0048] In the process of S220, the processing circuit 110 performs the following process as cranking to suppress pre-ignition. That is, if the processing circuit 110 determines that there is a possibility of pre-ignition occurring, it performs a reduction process that lowers the cranking rotation speed NCR compared to when it is determined that there is no possibility of pre-ignition occurring. The cranking rotation speed NCR is the rotational speed of the crankshaft 18 during cranking, which is performed by driving and controlling the first motor generator 310 during restart.

[0049] On the other hand, if the process in S210 determines that there is little likelihood of pre-ignition occurring during restart (S210: NO), the processing circuit 110 performs normal cranking (S230).

[0050] Then, when either the process in S220 or the process in S230 is executed, the processing circuit 110 terminates this process. Figure 4 shows normal cranking and cranking with pre-ignition suppression. The dashed line Ln in Figure 4 shows the change in cranking speed NCR when normal cranking is selected by the process in S230. The solid line Lp in Figure 4 shows the change in cranking speed NCR when cranking with pre-ignition suppression is selected by the process in S220.

[0051] As shown in Figure 4, in cranking for pre-ignition suppression, the target value NCRt of the cranking rotation speed NCR is set to a lower value than the target value (NCRt) in normal cranking.

[0052] Furthermore, in cranking designed to suppress pre-ignition, the rate at which the cranking rotation speed NCR increases until the target value NCRt is reached during cranking is slower compared to the rate at which it increases during normal cranking.

[0053] Thus, if it is determined that there is a high probability of pre-ignition occurring during restart, the processing circuit 110 reduces the cranking rotation speed NCR by lowering the target value NCRt and lowering the rate at which the cranking rotation speed NCR increases.

[0054] <Operation and Effects of This Embodiment> (1) Reducing the cranking speed NCR during cranking increases the compression stroke time. A longer compression stroke time increases the time for heat to be transferred from the gas inside the cylinder, whose temperature rises during the compression process, to the wall of the cylinder 16, thus increasing cooling losses. Increased cooling losses lower the compression end temperature, making pre-ignition less likely to occur.

[0055] Therefore, in this embodiment, if it is determined that there is a possibility of pre-ignition occurring during restart, a reduction process is performed to lower the cranking rotation speed NCR. More specifically, both the target value NCRt of the cranking rotation speed NCR during cranking and the rate at which the cranking rotation speed NCR increases during cranking are reduced. As a result, the occurrence of pre-ignition during restart can be suppressed.

[0056] (2) The processing circuit 110 performs a calculation process to calculate a total score St based on a relational value that is involved in the likelihood of preignition occurring. The processing circuit 110 determines whether or not preignition is likely to occur based on the value of the total score St.

[0057] Therefore, it is possible to determine whether or not there is a high probability of a preignition occurring based on the total score St mentioned above. (3) Coolant temperature THW, intermittent stop time Ts, and intake air temperature THA are all values ​​that are related to the likelihood of pre-ignition occurring. Therefore, based on the coolant temperature THW, intermittent stop time Ts, and intake air temperature THA, the above total score St can be appropriately calculated to determine whether or not there is a high probability of pre-ignition occurring.

[0058] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0059] As mentioned above, the following are related values ​​that are influencing the likelihood of pre-ignition: coolant temperature THW, intermittent stop time Ts, intake air temperature THA, actual compression ratio, injection ratio Rp, the degree of aging deterioration of the port injectors 83 and in-cylinder injectors 84, and fuel octane rating. Therefore, the score S may be calculated based on at least one of these values.

[0060] For example, a score S, which increases with increasing actual compression ratio, may be calculated and added to the total score St mentioned above. The actual compression ratio of the internal combustion engine 10 can be determined from the mechanical compression ratio obtained from the stroke amount of the piston 15 and the valve timing of the intake valve 81 set at restart, as described above. Therefore, a score S can be calculated based on these mechanical compression ratios and the valve timing of the intake valve 81 set at restart.

[0061] Alternatively, a score S, which increases with increasing injection ratio Rp, may be calculated and added to the total score St mentioned above. Furthermore, a score S may be calculated, the value of which increases with increasing degree of aging deterioration of the port injection valve 83 and in-cylinder injection valve 84, and this score may be added to the above total score St. Note that the degree of aging deterioration of the injection valves tends to increase with increasing total mileage of the vehicle or with increasing total operating time of the internal combustion engine 10. Therefore, a score S may be calculated, the value of which increases with increasing total mileage of the vehicle or with increasing total operating time of the internal combustion engine 10, and this score may be added to the above total score St.

[0062] Alternatively, a score S, which increases as the fuel octane rating decreases, may be calculated and added to the total score St mentioned above. As mentioned above, the values ​​related to the likelihood of pre-ignition include those related to the compression end temperature during cranking and those related to whether or not there is fuel present that induces pre-ignition during restart.

[0063] Therefore, a first total score St1 is calculated, which is the sum of scores S based on each of the above-mentioned relational values ​​related to the compression end temperature during cranking. A second total score St2 is calculated, which is the sum of scores S based on each of the above-mentioned relational values ​​related to whether or not there is fuel that induces pre-ignition during restart. If the first total score St1 is greater than or equal to a predetermined threshold St1ref and the second total score St2 is greater than or equal to a predetermined threshold St2ref, the above-described reduction process may be performed.

[0064] The target value NCRt may be set to be variable so that the rotational speed decreases as the total score St is larger. The cranking rotation speed NCR may be set to a variable rate such that the rate of increase of the cranking rotation speed NCR slows down as the total score St value increases.

[0065] • In the deceleration process, both the target value NCRt of the cranking rotation speed NCR and the rate of increase of the cranking rotation speed NCR were reduced, but either one of them may be reduced. The likelihood of a pre-ignition occurring during a restart was determined based on a score. Alternatively, the likelihood of a pre-ignition occurring could be determined based on the magnitude of the aforementioned relationship values ​​without calculating such a score.

[0066] • The vehicle's hybrid system is not limited to the one shown in Figure 1; other hybrid systems may also be used. The number of motor generators equipped in the vehicle can be changed as needed.

[0067] The vehicle may be equipped only with an internal combustion engine 10 as the prime mover, and idle stop control may be implemented in the internal combustion engine 10. In this example of modification, similar effects and functions can be obtained, for example, by adjusting the rotational speed of the starter motor that rotates the crankshaft 18 when the engine is started.

[0068] The control device 100 is not limited to one that includes a CPU and memory and performs software processing. For example, the control device 100 may include a dedicated hardware circuit, such as an ASIC, that performs hardware processing for at least a portion of what is processed by software in the above embodiment. That is, the control device 100 may include a processing circuit having any of the following configurations (a) to (c): (a) A processing circuit comprising one or more processing units that perform all of the above processing according to a program, and one or more program storage devices such as ROMs that store the program. (b) A processing circuit comprising one or more processing units and one or more program storage devices that perform a portion of the above processing according to a program, and one or more dedicated hardware circuits that perform the remaining processing. (c) A processing circuit comprising one or more dedicated hardware circuits that perform all of the above processing. The program storage device, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. [Explanation of symbols]

[0069] 10...Internal combustion engine 11...Cylinder block 12...Cylinder head 13...Head cover 15...Piston 16...Cylinder 17...Combustion chamber 18...Crankshaft 19...Crankcase 20...Intake passage 23...Spark plug 28...Throttle valve 30...Intake port 50...Crank angle sensor 51...Air flow meter 52...Accelerator pedal input sensor 53...Intake air temperature sensor 56...Vehicle speed sensor 57...Water temperature sensor 58...Intake cam angle sensor 59...Exhaust cam angle sensor 70...Exhaust port 81...Intake valve 82...Exhaust valve 83...Port injection valve 84...In-cylinder injection valve 85...Intake variable valve timing mechanism 86...Exhaust variable valve timing mechanism 90...Exhaust passage 100...Control device 110...Processing circuit 300...Planetary gear mechanism 310...First motor generator 310a…Rotating shaft 320…Second motor generator 320a…Rotating shaft 330…Inverter 340…Inverter 350…First rotation angle sensor 360…Second rotation angle sensor 400…Drive wheel

Claims

1. A control device for an internal combustion engine that performs intermittent stopping, It has a processing circuit, The processing circuit includes a determination process that determines whether or not there is a high probability of pre-ignition occurring when the internal combustion engine is restarted after the intermittent stop, If the determination process determines that there is a high probability of pre-ignition occurring, a reduction process is performed to lower the cranking speed, which is the rotational speed of the crankshaft of the internal combustion engine during cranking performed at the time of restart, compared to when it is determined that there is no high probability of pre-ignition occurring. Control device for internal combustion engines.

2. The aforementioned processing circuit is The system performs a calculation process to calculate a score based on the relationship values ​​that are involved in the likelihood of preignition occurring, In the aforementioned determination process, it is determined whether or not there is a high probability of a preignition occurring based on the value of the score. A control device for an internal combustion engine according to claim 1.

3. The aforementioned relationship includes at least one of the following: the coolant temperature of the internal combustion engine, the intermittent stop time, the intake air temperature of the internal combustion engine, the actual compression ratio of the internal combustion engine, the degree of aging deterioration of the fuel injectors of the internal combustion engine, and the fuel octane number of the internal combustion engine. The control device for an internal combustion engine according to claim 2.

4. The internal combustion engine includes a port injection valve that injects fuel into the intake port and an in-cylinder injection valve that injects fuel directly into the combustion chamber. The aforementioned relationship includes at least one of the following: the coolant temperature of the internal combustion engine, the intermittent stop time, the intake air temperature of the internal combustion engine, the actual compression ratio of the internal combustion engine, the degree of aging deterioration of the fuel injectors of the internal combustion engine, the fuel octane number of the internal combustion engine, and the injection ratio, which is the ratio of the amount of fuel injected from the port injectors to the amount of fuel injected from the in-cylinder injectors. The control device for an internal combustion engine according to claim 2.

5. In the reduction process, at least one of the target value of the cranking rotation speed during cranking and the rate at which the cranking rotation speed increases during cranking is reduced. A control device for an internal combustion engine according to claim 1.

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