Control device for internal combustion engine

Abstract

To suppress deterioration of fuel economy and furthermore to restrict degradation of a catalyst.SOLUTION: A control device 70 performs: degradation determination processing determining presence / absence of degradation of a three-way catalyst 32; stop processing stopping fuel injection when engine rotational speed is equal to or less than a determination value, if a stop request for stopping operation of an internal combustion engine 10 exists; and if degradation of a three-way catalyst 32 is determined to be present, change processing for reducing a determination value which determines the engine rotational speed, compared to when degradation of the three-way catalyst 32 is determined to be absent.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] When an internal combustion engine is stopped, oxygen is supplied to the catalyst between the time fuel injection is stopped and the time the crankshaft stops rotating, which can cause catalyst deterioration. Therefore, for example, in the internal combustion engine described in Patent Document 1, fuel injection in the internal combustion engine is continued to combust the air-fuel mixture even when there is no demand for output from the internal combustion engine and the operation of the internal combustion engine can be stopped. By continuing to combust the air-fuel mixture in this way, the supply of oxygen to the catalyst is reduced, thereby suppressing catalyst deterioration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-163393 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the internal combustion engine described in Patent Document 1, even in situations where the operation of the internal combustion engine can be stopped, fuel injection in the internal combustion engine continues to burn the mixture in order to prevent catalyst deterioration, which results in a deterioration in fuel efficiency. [Means for solving the problem]

[0005] The control device for an internal combustion engine that solves the above problem is a control device for an internal combustion engine that has a catalyst in an exhaust passage. The greater the vehicle's cumulative mileage, the larger the calculated value. The catalyst The degree of deterioration is compared with a preset threshold value. a deterioration determination process; and a stop process for stopping fuel injection in the internal combustion engine when an engine rotation speed of the internal combustion engine becomes equal to or less than a determination value when there is a stop request to stop operation of the internal combustion engine. The degree of deterioration is equal to or greater than the threshold value.In the case of The degree of deterioration is less than the threshold value. and executing a change process to make the determination value smaller than in the case where the determination value is ...

[0006] According to this configuration, The degree of deterioration is above the threshold In the case of The degree of deterioration is below the threshold Compared to the case where fuel injection is stopped, the engine rotation speed is lower, so the time between stopping fuel injection and stopping crankshaft rotation is shorter. Therefore, the amount of oxygen supplied to the catalyst between stopping fuel injection and stopping crankshaft rotation is reduced. Therefore, by stopping fuel injection, it is possible to suppress deterioration of the catalyst while suppressing deterioration of fuel economy. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing a configuration of a drive system and a control device for a vehicle according to an embodiment; [Figure 2] 4 is a flowchart showing a procedure of a process executed by the control device of the embodiment. [Figure 3] 4 is a flowchart showing a procedure of a process executed by the control device of the embodiment. [Figure 4] 4 is a timing chart showing the operation of the embodiment, in which Fig. 4(A) shows the accelerator operation amount, Fig. 4(B) shows the engine rotation speed, Fig. 4(C) shows the direct injection flag, Fig. 4(D) shows the stop execution flag, and Fig. 4(E) shows the first MG torque over time. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of a control device for an internal combustion engine will be described. <Configuration of vehicle equipped with internal combustion engine and control device> As shown in FIG. 1, an internal combustion engine 10 mounted on a vehicle VC includes, for example, four cylinders #1 to #4.

[0009] A throttle valve 14 is provided in an intake passage 12 of the internal combustion engine 10. A port injection valve 16 that injects fuel into the intake port 12a is provided in an intake port 12a, which is a downstream portion of the intake passage 12. This port injection valve 16 is a fuel injection valve that supplies fuel to the cylinders of the internal combustion engine 10.

[0010] Air drawn into the intake passage 12 and fuel injected from the port injection valve 16 flow into the combustion chamber 20 as the intake valve 18 opens, and are thereby supplied to each cylinder. Fuel is also directly injected into the combustion chamber 20 from an in-cylinder injection valve 22. This in-cylinder injection valve 22 is also a fuel injection valve that supplies fuel to the cylinders of the internal combustion engine 10. The air-fuel mixture in the combustion chamber 20 is combusted as a result of spark discharge from an ignition device 24. The combustion energy generated at this time is converted into rotational energy of a crankshaft 26.

[0011] The air-fuel mixture burned in the combustion chamber 20 is discharged as exhaust gas into an exhaust passage 30 when an exhaust valve 28 opens. A three-way catalyst 32 having oxygen storage capacity and a gasoline particulate filter (GPF 34) are provided in the exhaust passage 30. The GPF 34 is a filter that collects PM and supports a three-way catalyst.

[0012] The crankshaft 26 is mechanically connected to a carrier C of a planetary gear mechanism 50 that constitutes a power split device. A rotating shaft 52a of a first motor generator 52 (hereinafter referred to as the first MG 52) is mechanically connected to a sun gear S of the planetary gear mechanism 50. Furthermore, a rotating shaft 54a of a second motor generator 54 (hereinafter referred to as the second MG 54) and drive wheels 60 are mechanically connected to a ring gear R of the planetary gear mechanism 50.

[0013] The first MG 52 functions as a generator that generates electricity by utilizing the engine output, and also functions as a starting starter (electric motor) that cranks the crankshaft 26 when starting the internal combustion engine 10. The first MG 52 is a motor that can apply torque to the crankshaft 26.

[0014] The second MG 54 functions as an electric motor that generates driving force for the drive wheels 60, and also functions as a generator that generates electricity by regenerative braking when the vehicle VC is decelerating. An AC voltage is applied to the terminals of the first MG 52 by a first inverter 56. Furthermore, an AC voltage is applied to the terminals of the second MG 54 by a second inverter 58. Both the first inverter 56 and the second inverter 58 are power conversion circuits that convert the terminal voltage of a battery 59, which serves as a DC voltage source, into an AC voltage and output it.

[0015] The control device 70 operates operating parts of the internal combustion engine 10, such as the throttle valve 14, the port injection valve 16, the in-cylinder injection valve 22, and the ignition device 24, in order to control the torque, exhaust component ratio, etc., which are control variables of the internal combustion engine 10 as the controlled object.

[0016] The control device 70 also operates the first inverter 56 to control the torque, which is the control variable of the first MG 52 as a control target, and the control device 70 also operates the second inverter 58 to control the torque, which is the control variable of the second MG 54 as a control target.

[0017] 1 shows operation signals MS1 to MS6 for the throttle valve 14, the port injection valve 16, the direct injection valve 22, the ignition device 24, the first inverter 56, and the second inverter 58, respectively.

[0018] The control device 70 references the intake air amount GA detected by the air flow meter 80 and the output signal Scr of the crank angle sensor 82 to control the controlled variable of the internal combustion engine 10. The control device 70 also references the water temperature THW detected by the water temperature sensor 84 and the output signal Sp of the output-side rotation angle sensor 86 that detects the rotation angle of the ring gear R. The control device 70 also references the temperature Tb of the battery 59 detected by the temperature sensor 87, the charge / discharge current I of the battery 59 detected by the current sensor 88, and the terminal voltage Vb of the battery 59 detected by the voltage sensor 89. The control device 70 also references the output signal Sm1 of the first rotation angle sensor 90 that detects the rotation angle of the first MG 52 to control the controlled variable of the first MG 52. The control device 70 calculates a first rotation speed Nmg1, which is the rotation speed of the rotary shaft 52a of the first MG 52, based on the output signal Sm1. The control device 70 also references the output signal Sm2 of the second rotation angle sensor 92, which detects the rotation angle of the second MG 54, to control the control amount of the second MG 54. The control device 70 calculates a second rotation speed Nmg2, which is the rotation speed of the rotary shaft 54a of the second MG 54, based on the output signal Sm2. The control device 70 also references an accelerator operation amount ACCP, which is the depression amount of the accelerator pedal, detected by an accelerator sensor 94. The control device 70 calculates an engine rotation speed NE based on the output signal Scr of the crank angle sensor 82. The control device 70 also calculates an engine load factor KL based on the engine rotation speed NE and the intake air amount GA. The engine load factor KL represents the ratio of the current cylinder inflow air amount to the cylinder inflow air amount when the internal combustion engine 10 is operating steadily under full load. The cylinder inflow air amount is the amount of air flowing into each cylinder during the intake stroke.

[0019] The control device 70 includes a CPU 72, a ROM 74, a peripheral circuit 76, and a communication line 78. The CPU 72, the ROM 74, and the peripheral circuit 76 are capable of communicating with each other via the communication line 78. Here, the peripheral circuit 76 includes a circuit that generates a clock signal that regulates internal operations, a power supply circuit, a reset circuit, etc. The control device 70 controls the control amount by the CPU 72 executing a program stored in the ROM 74.

[0020] For example, the control device 70 calculates the required torque required for the vehicle VC to travel based on the accelerator operation amount ACCP and the vehicle speed SP. The control device 70 also controls the required output power Pe of the internal combustion engine 10 and the output torques of the first MG 52 and the second MG 54 so as to satisfy the required torque of the vehicle VC.

[0021] Furthermore, when the required output Pe becomes "0" and there is a request to stop the operation of the internal combustion engine 10, the control device 70 automatically stops the operation of the internal combustion engine 10, while when the required output Pe becomes greater than "0", the control device 70 performs intermittent operation to automatically start the internal combustion engine 10. Examples of when the required output Pe becomes "0" include when the accelerator operation amount ACCP becomes "0" or when the required torque of the vehicle VC can be satisfied by the output torque of the second MG 54 alone. Examples of when the required output Pe becomes greater than "0" include when the required torque of the vehicle VC can no longer be satisfied by the output torque of the second MG 54 alone.

[0022] <Processing performed by the control device> Fig. 2 shows the procedure of the process executed by the control device 70. The process shown in Fig. 2 is started when the required output Pe of the internal combustion engine 10 becomes "0" and a stop request to stop the operation of the internal combustion engine 10 is generated. Note that, hereinafter, the step number of each process is represented by a number preceded by "S."

[0023] 2, first, the control device 70 determines whether the current catalyst temperature Tc1 is equal to or greater than a threshold value Tc1ref (S100). The catalyst temperature Tc1 is the temperature of the three-way catalyst 32 and is calculated by the control device 70 based on the engine rotation speed NE, the engine load factor KL, the vehicle speed SP, etc. The threshold value Tc1ref is, for example, the lowest temperature at which the three-way catalyst 32 begins to deteriorate. The process of S100 determines whether the three-way catalyst 32 is in a state where deterioration is likely to progress. If the catalyst temperature Tc1 is equal to or greater than the threshold value Tc1ref and the three-way catalyst 32 is in a state where deterioration is likely to progress, a positive determination is made. However, if the catalyst temperature Tc1 is less than the threshold value Tc1ref and the three-way catalyst 32 is in a state where deterioration is unlikely to progress, a negative determination is made.

[0024] If the determination in S100 is affirmative, the control device 70 determines whether the deterioration level R is equal to or greater than the threshold value Rref (S110). The deterioration level R is a value indicating the degree of deterioration of the three-way catalyst 32. The control device 70 calculates the deterioration level R so that the value of the deterioration level R increases as the accumulated mileage of the vehicle VC increases. Note that the deterioration level R may also be calculated based on other parameters. For example, the deterioration level R may be calculated by calculating an accumulated value of the amount of heat received by the three-way catalyst 32, and the deterioration level R may be calculated so that the value of the deterioration level R increases as the accumulated value increases.

[0025] The threshold value Rref is a preset adaptive value for determining whether or not the three-way catalyst 32 has deteriorated, and if the deterioration level R is equal to or greater than the threshold value Rref, it is determined that the catalyst has deteriorated, whereas if the deterioration level R is less than the threshold value Rref, it is determined that the catalyst has not deteriorated. In this way, the process of S110 is a deterioration determination process for determining whether or not the catalyst has deteriorated.

[0026] If the determination in S110 is affirmative, the control device 70 assigns the second speed NEref2, which is a second determination value, to the determination value NEref (S120). When a stop request is issued, the control device 70 executes a stop process to stop fuel injection in the internal combustion engine 10 when the engine rotation speed NE becomes equal to or less than the determination value NEref. The second speed NEref2 is a preset value, and is a rotation speed lower than the first speed NEref1, which will be described later. The process of S120 is a change process that reduces the determination value NEref when it is determined that there is catalyst degradation compared to when it is determined that there is no catalyst degradation, and is a process that is performed to suppress catalyst degradation.

[0027] After executing the process of S120, the control device 70 next determines whether the engine rotation speed NE is equal to or less than the first speed NEref1 (S130). When it is determined that the engine speed NE exceeds the first speed NEref1 (S130: NO), the control device 70 repeatedly executes the process of S130 until it is determined that the engine speed NE is equal to or less than the first speed NEref1.

[0028] If a positive determination is made in the processing of S130, the control device 70 sets the in-cylinder injection flag Fd to "ON" (S140). When the in-cylinder injection flag Fd is set to "ON", fuel injection is started only from the in-cylinder injection valve 22. Note that when a stop execution flag Fs, which will be described later, is set to "ON", the in-cylinder injection flag Fd is set to "OFF".

[0029] If a negative determination is made in the process of S100 or the process of S110, the control device 70 substitutes a first speed NEref1, which is a first determination value, into the determination value NEref (S150). The first speed NEref1 is a preset value, and is a rotation speed higher than the second speed NEref2.

[0030] After performing the process of S140 or the process of S150, the control device 70 next determines whether the current engine speed NE is equal to or less than a reference value NEref (S160). When it is determined that the engine speed NE exceeds the reference value NEref (S160: NO), the control device 70 repeatedly executes the process of S160 until it determines that the engine speed NE is equal to or less than the reference value NEref.

[0031] If the determination in the processing of S160 is affirmative, the control device 70 sets the stop execution flag Fs to "ON" (S170). Next, the control device 70 executes a stop process (S180). As this stop process, the control device 70 executes a process to stop fuel injection into the internal combustion engine 10. Then, this process ends.

[0032] Fig. 3 shows the procedure of another process executed by the control device 70. The process shown in Fig. 3 is started when the stop execution flag Fs is set to "ON" in the process of S170 described above, for example. 3, first, the control device 70 determines whether the current catalyst temperature Tc1 is equal to or higher than the threshold value Tc1ref (S200). The process of S200 is the same as the process of S100 described above.

[0033] In the process of S200, if it is determined that the catalyst temperature Tc1 is equal to or higher than the threshold value Tc1ref and that the three-way catalyst 32 is in a state where deterioration is likely to progress (S200: YES), the control device 70 determines whether the current vehicle speed SP is equal to or higher than a reference value SPref (S210). The reference value SPref is a vehicle speed at which an increase in vehicle vibration due to execution of a torque increase process (described later) can be masked by vibration caused by vehicle travel, and is a predetermined suitable value.

[0034] If it is determined that the vehicle speed SP is equal to or greater than the reference value SPref (S210: YES), the control device 70 performs torque control of the first MG 52 by substituting the second torque T2 for the first MG torque Tm1, which is the required value for the output torque of the first MG 52 (S220). The second torque T2 is a torque that resists the rotation of the crankshaft 26 and has a greater resistance to the rotation of the crankshaft 26 than the first torque T1, which will be described later. The absolute value of the output torque of the first MG 52 indicates the magnitude of the torque. Furthermore, the output torque of the first MG 52 indicates torque that acts in the same direction as the rotation direction of the crankshaft 26 with a positive value. On the other hand, the output torque of the first MG 52 indicates torque that acts in the opposite direction to the rotation direction of the crankshaft 26, i.e., torque that resists the rotation of the crankshaft 26 with a negative value. Then, when the second torque T2 is substituted for the first MG torque Tm1 in the processing of S220, the control device 70 executes a torque application process that controls the torque of the first MG 52 so that the second torque T2 is applied from the first MG 52 to the crankshaft 26. This torque application process is performed to suppress catalyst deterioration. Furthermore, the processing of S220 corresponds to a torque increase process that increases the torque applied from the motor that resists rotation of the crankshaft when the catalyst is in a state in which deterioration is likely to progress compared to when the catalyst is in a state in which deterioration is unlikely to progress.

[0035] If a negative determination is made in the process of S200 or the process of S210, the control device 70 performs torque control of the first MG 52 by substituting the first torque T1 for the first MG torque Tm1 (S230). The first torque T1 is a preset negative value whose absolute value is smaller than that of the second torque T2. When the first torque T1 is substituted for the first MG torque Tm1 in the process of S230, the control device 70 executes torque application processing to control the torque of the first MG 52 so that the first torque T1 is applied from the first MG 52 to the crankshaft 26. This torque application processing is also performed to suppress catalyst deterioration.

[0036] After the process of S220 or S230 is performed, the control device 70 next determines whether the rotation of the crankshaft 26 has stopped based on the current engine rotation speed NE (S240).

[0037] If it is determined that the rotation of the crankshaft 26 has not stopped (S240: NO), the control device 70 repeatedly executes the process of S240 until it determines that the rotation of the crankshaft 26 has stopped.

[0038] If the determination in S240 is affirmative, the control device 70 substitutes the first required torque T1* for the first MG torque Tm1 and performs torque control of the first MG 52, thereby terminating the torque application process (S250). The first required torque T1* is a value calculated based on vehicle travel requirements, etc., and is set to "0," for example, when the vehicle travels using only the output torque of the second MG 54. The control device 70 then terminates this process.

[0039] <effect> In Fig. 4, the solid lines show the transitions of the respective values ​​when the second speed NEref2 is set as the determination value NEref and the second torque T2 is set as the first MG torque Tm1 in the torque application process. Fig. 4(A) shows the transitions of the accelerator operation amount, Fig. 4(B) shows the transitions of the engine rotation speed, Fig. 4(C) shows the transitions of the direct injection flag, Fig. 4(D) shows the transitions of the stop execution flag, and Fig. 4(E) shows the transitions of the first MG torque.

[0040] When the accelerator pedal is released at time t1, the accelerator operation amount ACCP decreases toward "0," and the engine rotation speed NE also decreases. Then, at time t2, when the engine speed NE drops to the first speed NEref1, the direct injection flag Fd is set to "ON" and fuel injection from only the direct injection valves is started.

[0041] Furthermore, at time t3, when the engine speed NE decreases to the second speed NEref2, the stop execution flag Fs is set to "ON," thereby executing the stop process and terminating the combustion of the air-fuel mixture. Also at time t3, the torque application process is started, thereby applying a second torque T2, the absolute value of which is greater than that of the first torque T1, from the first MG 52 to the crankshaft 26. As a result, as indicated by the two-dot chain line, the rate at which the engine speed NE decreases becomes faster than the rate at which the engine speed NE decreases when the first torque T1 is applied from the first MG 52. Then, at time t4, when the rotation of the crankshaft 26 stops, the torque application process ends, and the first MG torque Tm1 is changed from the second torque T2 to the first required torque T1* (for example, "0").

[0042] <Effects> The effects of this embodiment will be described. (1) When the process of S110 shown in FIG. 2 determines that the three-way catalyst 32 has deteriorated, a second speed NEref2, which is lower than the first speed NEref1, is set as the determination value NEref. Therefore, when it is determined that the three-way catalyst 32 has deteriorated, the engine rotation speed NE at which fuel injection is stopped is lower than when it is determined that the three-way catalyst 32 has not deteriorated. Therefore, when the second speed NEref2 is set as the determination value NEref, the time from when fuel injection is stopped to when the rotation of the crankshaft 26 stops is shorter by the period from time t2 to time t3 shown in FIG. 4 compared to when the first speed NEref1 is set. Therefore, the amount of oxygen supplied to the three-way catalyst 32 from when fuel injection is stopped to when the rotation of the crankshaft 26 stops is reduced. Therefore, by stopping fuel injection, it is possible to suppress deterioration of the three-way catalyst 32 while suppressing deterioration in fuel economy.

[0043] (2) When the second speed NEref2 is set as the determination value NEref, the fuel economy is likely to deteriorate compared to when the first speed NEref1 is set because the mixture is burned at a lower rotation speed. Therefore, in this configuration, the second speed NEref2 is set as the determination value NEref when it is determined that the three-way catalyst 32 has deteriorated. Therefore, deterioration in fuel economy can be suppressed compared to when the second speed NEref2 is set as the determination value NEref regardless of whether the three-way catalyst 32 has deteriorated.

[0044] (3) Lowering the engine speed at which fuel injection is stopped can result in insufficient mixing of the air-fuel mixture, which can lead to unstable combustion. Fuel injection using the direct injection valve 22 is less likely to cause combustion instability due to insufficient mixing of the air-fuel mixture than fuel injection using the port injection valve 16, and has the characteristic of stabilizing combustion even at low engine speeds. Therefore, in this embodiment, fuel is injected only from the direct injection valve 22 when the engine speed NE is between the first speed NEref1 and the second speed NEref2, which can lead to unstable combustion. Therefore, even if the engine speed at which fuel injection is stopped is lowered when it is determined that the three-way catalyst 32 has deteriorated, the air-fuel mixture can be properly combusted.

[0045] (4) The torque application process is executed after fuel injection in the internal combustion engine 10 is stopped. This shortens the time between stopping fuel injection and stopping rotation of the crankshaft 26. This reduces the amount of oxygen supplied to the three-way catalyst 32 during the period between stopping fuel injection and stopping rotation of the crankshaft 26, thereby further suppressing deterioration of the three-way catalyst 32. In this embodiment, when the process of S200 shown in FIG. 3 determines that the three-way catalyst 32 is in a state where deterioration is likely to progress, a second torque T2 greater than the first torque T1 is set as the torque resisting rotation of the crankshaft 26. This means that when the three-way catalyst 32 is in a state where deterioration is likely to progress, the torque resisting rotation of the crankshaft 26 is increased compared to when the three-way catalyst 32 is in a state where deterioration is unlikely to progress. This further shortens the time between stopping fuel injection and stopping rotation of the crankshaft 26 when deterioration of the three-way catalyst 32 is likely to progress. Therefore, the amount of oxygen supplied to the three-way catalyst 32 between the time fuel injection is stopped and the time the rotation of the crankshaft 26 stops is further reduced, thereby making it possible to suppress deterioration of the three-way catalyst 32 even in a state in which deterioration of the three-way catalyst 32 is likely to progress.

[0046] (5) When the torque increase process described above is performed, the rotational speed of the crankshaft 26 decreases, which increases vehicle vibration and may cause discomfort to vehicle occupants. When the vehicle speed is relatively high, the vibration caused by the vehicle traveling increases, so the increase in vehicle vibration caused by the torque increase process is masked. Therefore, in this embodiment, the torque increase process is performed when the vehicle speed SP is equal to or greater than the predetermined reference value SPref. Therefore, it is possible to suppress discomfort to vehicle occupants caused by the increase in vehicle vibration caused by the execution of the torque increase process.

[0047] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0048] The processes of S130 and S140 shown in Fig. 2 may be omitted. Even in this case, effects other than (3) above can be obtained. The process of S210 shown in Fig. 3 may be omitted. Even in this case, effects other than (5) above can be obtained.

[0049] The series of processes shown in Fig. 3 may be omitted. Even in this case, effects other than those of (4) and (5) above can be obtained. The GPF 34 is not limited to being provided downstream of the three-way catalyst 32 in the exhaust passage 30. Furthermore, providing a GPF 34 in the exhaust passage itself is not essential. The GPF 34 is not limited to being a filter carrying a three-way catalyst. For example, if a three-way catalyst is provided upstream, the GPF 34 may be a filter alone.

[0050] The hybrid vehicle is not limited to a series-parallel hybrid vehicle. For example, it may be a parallel hybrid vehicle. The number of motor generators provided in the vehicle VC can be changed as needed.

[0051] The series of processes shown in FIG. 2 may be executed in a vehicle equipped with only an internal combustion engine as a prime mover. The control device 70 is not limited to a device equipped with a CPU 72 and a ROM 74 and executing software processing. For example, it may be equipped with a dedicated hardware circuit, such as an ASIC, that performs hardware processing on at least a portion of the software processing performed in the above embodiments. That is, the control device may have any of the following configurations (a) to (c): (a) A processing device that executes all of the above processing according to a program, and a program storage device, such as a ROM, that stores the program; (b) A processing device and program storage device that executes part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing; or (c) A dedicated hardware circuit that executes all of the above processing. Here, the software execution device equipped with a processing device and program storage device, and the dedicated hardware circuit may be one or any multiple number. [Explanation of symbols]

[0052] 10...Internal combustion engine 16...Port injection valve 20...Combustion chamber 22...In-cylinder injection valve 26...Crankshaft 32...Three-way catalyst 34...GPF 50...Planetary gear mechanism 52...First motor generator (first MG) 52a...Rotation axis 54...Second motor generator (second MG) 54a...Rotation axis 56...First inverter 58...Second inverter 59...Battery 60...Drive wheels 70...Control device

Claims

[Claim 1] A control device for an internal combustion engine equipped with a catalyst in an exhaust passage, the internal combustion engine includes a port injection valve that injects fuel into an intake port and an in-cylinder injection valve that injects fuel into a combustion chamber, a deterioration determination process for comparing the degree of deterioration of the catalyst, which is calculated to be a larger value as the cumulative mileage of the vehicle increases, with a preset threshold value; a stop process for stopping fuel injection in the internal combustion engine when an engine rotation speed of the internal combustion engine becomes equal to or less than a determination value when there is a stop request for stopping operation of the internal combustion engine; When the degree of deterioration is equal to or greater than the threshold, a change process is performed to reduce the determination value compared to when the degree of deterioration is less than the threshold; When the deterioration level is less than the threshold value, the determination value is set as a first determination value, and when the deterioration level is equal to or greater than the threshold value, the determination value is set as a second determination value. When the engine rotation speed is between the first determination value and the second determination value, fuel injection is performed only from the direct injection valve. Control device for internal combustion engines.

Images