JP2020176554A - Control device for internal combustion engine - Google Patents

Abstract

To provide a control device for an internal combustion engine capable of starting combustion control at appropriate timing when starting the engine.SOLUTION: A control device 100 determines whether leakage due to low oil-tightness occurs in a fuel injection valve 31 of an internal combustion engine 10. When determining that there is no leakage due to low oil-tightness, the control device 100 executes negative pressure securing processing for controlling an opening of a throttle valve 14 so that inside of an intake pipe downstream of the throttle valve 14 becomes a prescribed negative pressure state after engine speed increased by executing motoring in accordance with a start request exceeds a resonance speed area of the internal combustion engine 10, and starts combustion control of the internal combustion engine 10 after inside of the intake pipe becomes the prescribed negative pressure state by executing the negative pressure securing processing. When determining that there is leakage due to low oil-tightness, the control device executes start time control for starting the combustion control of the internal combustion engine 10 without executing the negative pressure securing processing after the engine speed increased by executing the motoring in accordance with the start request exceeds the resonance speed area.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for an internal combustion engine.

Patent Document 1 discloses a control device that adjusts the fuel injection amount and the like so that the engine rotation speed at the time of initial explosion exceeds the resonance speed range when the engine is started.

JP-A-2009-228538

When starting the engine, the optimum time for starting combustion control such as fuel injection and ignition differs depending on various conditions, and it is desirable to start combustion control according to such various conditions.

An internal combustion engine control device for solving the above problems is applied to an internal combustion engine that is motorized by an electric motor when there is a start request. This control device executes an oil tightness determination process for determining the presence or absence of oil tightness leakage in the fuel injection valve included in the internal combustion engine, and if it is determined that there is no oil tightness leakage, the motor in accordance with a start request. After the engine rotation speed of the internal combustion engine, which is increased by the execution of the ring, exceeds the resonance speed range of the internal combustion engine, the throttle valve is set so that the inside of the intake pipe downstream of the throttle valve of the internal combustion engine becomes a specified negative pressure state. After the negative pressure securing process for adjusting the opening degree of the internal combustion engine is executed and the inside of the intake pipe is brought into the negative pressure state by the execution of the negative pressure securing process, the combustion control of the internal combustion engine is started, while the oil tightness. If it is determined that there is a leak, after the engine rotation speed of the internal combustion engine, which is increased by executing the motoring in accordance with the start request, exceeds the resonance speed range, the negative pressure securing process is not executed. Perform start-up control to start combustion control of the internal combustion engine.

According to the same configuration, after the engine rotation speed exceeds the resonance speed range due to the execution of motoring, combustion control is started and the first explosion occurs. Here, when there is no oil tight leakage in the fuel injection valve, the intake air amount of the internal combustion engine is reduced because the inside of the intake pipe becomes a specified negative pressure state after the engine rotation speed exceeds the resonance speed range. Combustion control is started after the state is reached. When the combustion control is started after the intake air amount is reduced in this way, the first explosion occurs as compared with the case where the combustion control is started immediately after the engine rotation speed exceeds the resonance speed range. Since the engine output torque at that time becomes small, it is possible to suppress the starting shock that tends to occur at the time of the first explosion.

Here, if the above-mentioned negative pressure securing process is executed when the fuel injection valve has an oil tight leak, fuel may leak from the fuel injection valve due to the secured negative pressure, and fuel is injected before combustion of the air-fuel mixture occurs. If fuel leaks from the valve, the leaked fuel may be discharged unburned into the exhaust passage. Therefore, in the same configuration, when the fuel injection valve has an oil leak, the combustion control is started without executing the negative pressure securing process after the engine rotation speed exceeds the resonance speed range. .. Therefore, it becomes possible to suppress the discharge of unburned fuel into the exhaust passage when the engine is started.

In this way, according to the same configuration, when there is no oil tight leakage in the fuel injection valve, after the engine rotation speed exceeds the resonance speed range, the combustion control is started after securing the negative pressure. Combustion control can be started at a time suitable for suppressing the starting shock. In addition, when there is an oil leak in the fuel injection valve, the combustion control is started immediately after the engine speed exceeds the resonance speed range, in order to suppress the discharge of unburned fuel to the exhaust passage. Combustion control can be started at an appropriate time.

The negative pressure specified above is the negative pressure when the intake air amount is reduced to the extent that the starting shock that may occur due to the initial explosion generated by the start of combustion control can be kept within the allowable range. For example, the negative pressure obtained during idle operation can be mentioned.

In the control device, the start-up control is performed under the condition that the temperature of the internal combustion engine is equal to or lower than the specified temperature, the condition that the temperature of the battery for driving the electric motor is equal to or lower than the specified temperature, and the charging of the battery. If at least one of the conditions that the rate is equal to or less than the specified charge rate is satisfied, before the engine rotation speed of the internal combustion engine, which is increased by the execution of the motoring according to the start request, reaches the resonance speed range. The process of starting the combustion control of the internal combustion engine may be executed.

When the temperature of the internal combustion engine is below the specified temperature and the friction of the internal combustion engine is large, or when the temperature of the battery that drives the motor is below the specified temperature and the output torque of the motor is low, or the charge rate of the battery Is less than the specified charge rate and the driveable time of the motor is short, the amount of electricity stored in the battery becomes insufficient before the engine rotation speed increased by motoring reaches the resonance speed range, and the engine rotation speed resonates. It can be difficult to exceed the speed range. Then, when the engine rotation speed cannot actually exceed the resonance speed range, the combustion control is not started, so that the internal combustion engine cannot be started. In this regard, according to the same configuration, if there is a risk that the amount of electricity stored in the battery will be insufficient before the engine speed reaches the resonance speed range, combustion control will be performed before the engine speed reaches the resonance speed range. To be started. Therefore, when the initial explosion occurs due to the start of combustion control and then passes through the resonance speed range in the process of increasing the engine rotation speed, the engine vibration becomes large, but at least the internal combustion engine can be started.

In the control device, the start-up control is increased by executing the motoring in accordance with the start request when the required value of the output torque of the internal combustion engine is equal to or more than a specified value when the internal combustion engine is started. After the engine rotation speed of the internal combustion engine exceeds the resonance speed range, a process of starting combustion control of the internal combustion engine may be executed without executing the negative pressure securing process.

According to the same configuration, when the required value of the output torque of the internal combustion engine when starting the internal combustion engine is larger than the specified value, that is, when the engine output is to be increased promptly when the engine is started, the engine rotation speed is increased. After exceeding the resonance speed range, combustion control is started without executing the negative pressure securing process. Therefore, after the engine rotation speed exceeds the resonance speed range, the combustion control is started earlier than the case where the above-mentioned negative pressure securing process is executed to secure the negative pressure and then the combustion control is started. The engine output can be increased.

In the control device, the internal combustion engine includes a sensor that detects the fuel pressure in the fuel injection valve, and the oil-tightness determination process measures the amount of decrease in the fuel pressure that has decreased due to the shutdown of the internal combustion engine. The process of determining that there is an oil leak may be executed when it is calculated from the detected value of the above and the calculated decrease amount is equal to or more than the specified determination value.

If there is an oil leak in the fuel injection valve, the fuel pressure inside the fuel injection valve will decrease while the internal combustion engine is shut down. Therefore, the oil leak will be based on the amount of decrease in the fuel pressure that was reduced during the shutdown. It is possible to determine the presence or absence of. Therefore, in the same configuration, the amount of decrease in fuel pressure is calculated from the detected value of the sensor, and when the calculated amount of decrease is equal to or greater than the specified determination value, a process of determining that there is an oil leak is executed. Therefore, according to the configuration, the presence or absence of oil leakage can be appropriately determined.

In the control device, the oil tightness determination process may execute a process of determining that there is an oil tightness leak when the operation stop time of the internal combustion engine before starting is equal to or longer than a specified determination value.

When there is an oil leak in the fuel injection valve, the fuel gradually leaks from the fuel injection valve while the internal combustion engine is stopped. Therefore, the longer the operation stop time, the larger the leakage amount. If motoring is performed in a state where the amount of leakage is large in this way, unburned fuel may be discharged to the exhaust passage until combustion is started. Therefore, if the combustion control is started as early as possible when the amount of fuel leak is large and the leaked fuel is burned at an early stage, the amount of unburned fuel discharged to the exhaust passage can be suppressed. Therefore, in the same configuration, when the operation stop time of the internal combustion engine before starting is equal to or longer than the specified determination value, a process of determining that there is an oil leak is executed. Therefore, if the operation stop time is longer than the specified judgment value and there is a possibility that the amount of fuel leaked from the fuel injection valve is large, it is determined that there is an oil leak, and the engine is started. The combustion control is started promptly without executing the above-mentioned negative pressure securing process. Therefore, even if the fuel injection valve has an oil leak, the amount of unburned fuel discharged to the exhaust passage can be suppressed.

When the negative pressure securing process is executed in the control device, the ignition timing of the internal combustion engine when the combustion control is started is set to the ignition timing at which the engine output becomes the lowest within the range in which the air-fuel mixture can be burned. The process of setting the ignition timing for output suppression may be executed.

According to the same configuration, since the ignition timing at the start of combustion control is set to the above-mentioned output suppression ignition timing, the engine output when the first explosion occurs can be suppressed. Therefore, when the negative pressure securing process is executed in order to suppress the starting shock, the starting shock can be further suppressed.

In the control device, when the electric motor is a first electric motor and the electric motor that transmits power to a drive shaft connected to a drive wheel of a vehicle is a second electric motor, the output shaft of the internal combustion engine is the output of the internal combustion engine. Is connected to a planetary gear mechanism that distributes the output torque to the output shaft of the first electric motor and the drive shaft, and the required value of the output torque of the second electric motor when the combustion control is started is lower than "0 Nm". When it is a torque and the required ignition timing after the occurrence of the first explosion is a timing on the advance side of the output suppression ignition timing, until the required value of the output torque of the second motor exceeds "0 Nm". The process of suspending the change of the ignition timing from the output suppression ignition timing to the required ignition timing may be executed.

When the internal combustion engine mounted on the vehicle equipped with the planetary gear mechanism is motorized and started by the first electric motor, the required value of the output torque of the second electric motor is from a torque lower than "0 Nm" to "0 Nm". In this way, when the required value of the output torque of the second motor straddles "0 Nm", a rattling noise is generated from the gear of the planetary gear mechanism. There is. Here, if the output torque of the internal combustion engine suddenly increases when the required value of the output torque of the second electric motor straddles "0 Nm", such rattling noise may increase.

In this regard, according to the same configuration, when the required ignition timing after the occurrence of the first explosion is on the advance side of the output suppression ignition timing and the engine output increases, the output torque of the second motor is required. The change of the ignition timing from the output suppression ignition timing to the required ignition timing is suspended until the value exceeds "0 Nm". Therefore, a sudden increase in the output torque of the internal combustion engine when the required value of the output torque of the second electric motor straddles "0 Nm" is suppressed, and thereby the rattling noise generated from the planetary gear mechanism can be suppressed.

In the control device, when the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine is the output of the internal combustion engine. Is connected to a planetary gear mechanism that distributes the output torque to the output shaft of the first electric motor and the drive shaft, and the required value of the output torque of the second electric motor when the combustion control is started is lower than "0 Nm". When the torque and the required ignition timing after the occurrence of the first explosion are on the advance side of the output suppression ignition timing, the ignition timing is changed from the output suppression ignition timing to the required ignition timing. The rate of change of the ignition timing in the process until the required value of the output torque of the second motor exceeds "0 Nm", and the required value of the output torque of the second motor exceeds "0 Nm". You may execute the process to make it smaller than the later rate of change.

As described above, when the internal combustion engine mounted on the vehicle equipped with the planetary gear mechanism is motorized and started by the first electric motor, the required value of the output torque of the second electric motor is higher than "0 Nm". The torque may change from a low torque to a torque exceeding "0 Nm". In this way, when the required value of the output torque of the second motor straddles "0 Nm", the gears of the planetary gear mechanism are struck. Sound may be generated. Here, if the output torque of the internal combustion engine suddenly increases when the required value of the output torque of the second electric motor straddles "0 Nm", such rattling noise may increase.

In this regard, according to the same configuration, when the required ignition timing after the occurrence of the first explosion is on the advance side of the output suppression ignition timing and the engine output increases, the output torque of the second motor is required. The rate of change in the ignition timing in the process of changing the ignition timing from the output suppression ignition timing to the required ignition timing is reduced until the value exceeds "0 Nm", so that the increase in the output torque of the internal combustion engine becomes gradual. .. Therefore, a sudden increase in the output torque of the internal combustion engine when the required value of the output torque of the second electric motor straddles "0 Nm" is suppressed, and thereby the rattling noise generated from the planetary gear mechanism can be suppressed.

In the control device, the internal combustion engine includes a variable valve mechanism that changes the valve timing of the intake valve, and when the negative pressure securing process is executed, the valve timing when the combustion control is started. May be executed to set the valve timing for output suppression, which is the valve timing at which the engine output becomes the lowest in the range where the air-fuel mixture can be burned.

According to the same configuration, since the valve timing when the combustion control is started is set to the output suppression valve timing, the engine output when the first explosion occurs can be suppressed. Therefore, when the negative pressure securing process is executed in order to suppress the starting shock, the starting shock can be further suppressed.

In the control device, when the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine is the output of the internal combustion engine. Is connected to a power distribution mechanism that distributes the power to the output shaft of the first electric motor and the drive shaft, and the required value of the output torque of the second electric motor when the combustion control is started is lower than "0 Nm". When it is a torque and the required valve timing after the occurrence of the first explosion is the timing on the advance side of the output suppression valve timing, until the required value of the output torque of the second motor exceeds "0 Nm". The process of suspending the change of the valve timing from the output suppression valve timing to the required valve timing may be executed.

As described above, when the internal combustion engine mounted on the vehicle equipped with the planetary gear mechanism is motorized and started by the first electric motor, the required value of the output torque of the second electric motor is higher than "0 Nm". The torque may change from a low torque to a torque exceeding "0 Nm". In this way, when the required value of the output torque of the second motor straddles "0 Nm", the gears of the planetary gear mechanism are struck. Sound may be generated. Here, if the output torque of the internal combustion engine suddenly increases when the required value of the output torque of the second electric motor straddles "0 Nm", such rattling noise may increase.

In this respect, according to the same configuration, when the required valve timing after the first explosion occurs is the timing on the advance side of the output suppression valve timing and the engine output increases, the output torque of the second electric motor is required. The change of the valve timing from the output suppression valve timing to the required valve timing is suspended until the value exceeds "0 Nm". Therefore, a sudden increase in the output torque of the internal combustion engine when the required value of the output torque of the second electric motor straddles "0 Nm" is suppressed, and thereby the rattling noise generated from the planetary gear mechanism can be suppressed.

In the control device, when the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine is the output of the internal combustion engine. Is connected to a planetary gear mechanism that distributes the power to the output shaft of the first electric motor and the drive shaft, and the required value of the output torque of the second electric motor when the combustion control is started is lower than "0 Nm". When it is a motor and the required valve timing after the occurrence of the first explosion is a timing on the advance side of the output suppression valve timing, the valve timing is changed from the output suppression valve timing to the required valve timing. The rate of change in valve timing in the process until the required value of the output torque of the second motor exceeds "0 Nm", and the required value of the output torque of the second motor exceeds "0 Nm". You may execute the process to make it smaller than the later rate of change.

As described above, when the internal combustion engine mounted on the vehicle equipped with the planetary gear mechanism is motorized and started by the first electric motor, the required value of the output torque of the second electric motor is higher than "0 Nm". The torque may change from a low torque to a torque exceeding "0 Nm". In this way, when the required value of the output torque of the second motor straddles "0 Nm", the gears of the planetary gear mechanism are struck. Sound may be generated. Here, if the output torque of the internal combustion engine suddenly increases when the required value of the output torque of the second electric motor straddles "0 Nm", such rattling noise may increase.

In this regard, according to the same configuration, when the required valve timing after the first explosion occurs is the timing on the advance side of the output suppression valve timing and the engine output increases, the output torque of the second electric motor is required. The increase in the output torque of the internal combustion engine becomes gradual because the rate of change in the valve timing in the process of changing the valve timing from the output suppression valve timing to the required valve timing is reduced until the value exceeds "0 Nm". .. Therefore, a sudden increase in the output torque of the internal combustion engine when the required value of the output torque of the second electric motor straddles "0 Nm" is suppressed, and thereby the rattling noise generated from the planetary gear mechanism can be suppressed.

The schematic diagram which shows the structure of the hybrid vehicle which includes the control device of the internal combustion engine in 1st Embodiment. The schematic diagram which shows the structure of the internal combustion engine of the same embodiment. The flowchart which shows the procedure of the control at the time of starting which the control device of the same embodiment executes. The flowchart which shows the procedure of the process which the control device of 2nd Embodiment executes. The flowchart which shows the procedure of the process executed by the control device of the same embodiment. The flowchart which shows the procedure of the process which the control apparatus of 3rd Embodiment executes. The flowchart which shows the procedure of the process executed by the control device of the same embodiment. The flowchart which shows a part of the procedure of the control at a start time in the modification example of 1st Embodiment.

(First Embodiment)
Hereinafter, the first embodiment in which the control device of the internal combustion engine is embodied will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the vehicle 500 is a hybrid vehicle including an internal combustion engine 10 and an electric motor as a prime mover, and the electric motors include a first motor generator (hereinafter, referred to as a first MG) 71, which is a first electric motor. It includes a second motor generator (hereinafter, referred to as a second MG) 72 which is a second electric motor.

The vehicle 500 includes a planetary gear mechanism 40. The planetary gear mechanism 40 is a mechanism that distributes the output of the internal combustion engine 10 to the rotor which is the output shaft of the first MG 71 and the drive shaft 60 connected to the drive wheels 62, and is arranged coaxially with the sun gear 41 and the sun gear 41. It has a ring gear 42 and a ring gear 42. A plurality of pinion gears that mesh with both the sun gear 41 and the ring gear 42 are arranged between the sun gear 41 and the ring gear 42, and each pinion gear is supported by the carrier 44.

The crankshaft 34 of the internal combustion engine 10 is connected to the carrier 44, and the rotor of the first MG 71 is connected to the sun gear 41. A drive shaft 60 is connected to the ring gear 42, and the drive shaft 60 is connected to the drive wheels 62 via a differential gear 61. The first MG 71 functions as a generator that generates electricity by using the engine output, and also functions as a starting starter (electric motor) when the internal combustion engine 10 is started.

The rotor of the second MG 72 is connected to the drive shaft 60 via the reduction mechanism 50. The second MG 72 functions as an electric motor that generates the driving force of the drive wheels 62, and also functions as a generator that generates electricity by the regenerative brake when the vehicle 500 decelerates.

The first MG 71 and the second MG 72 transfer power to and from the battery 78 via a PCU (Power Control Unit) 200. The PCU 200 includes a boost converter that boosts and outputs the DC voltage input from the battery 78, an inverter that converts the DC voltage boosted by the boost converter into an AC voltage, and outputs the DC voltage to each of the MGs 71 and 72.

As shown in FIG. 2, in the internal combustion engine 10, air is sucked into the combustion chamber 30 through the intake passage 11 provided with the surge tank 13 and the intake port 12, and is also injected into the intake port 12 from the fuel injection valve 31. The fuel is supplied to the combustion chamber 30. When the air-fuel mixture composed of air and fuel supplied to the combustion chamber 30 is ignited by the spark plug 32, the air-fuel mixture burns and the piston 33 reciprocates, and the output shaft of the internal combustion engine 10 The crankshaft 34 is rotated. The air-fuel mixture after combustion is exhausted from the combustion chamber 30 to the exhaust passage 21 via the exhaust port 22.

A throttle valve 14 for adjusting the intake air amount is provided in the intake passage 11 of the internal combustion engine 10. The opening degree of the throttle valve 14 is adjusted by an electric motor.
The intake port 12 is provided with an intake valve 15, and the exhaust port 22 is provided with an exhaust valve 25. The intake valve 15 and the exhaust valve 25 open and close with the rotation of the intake camshaft 16 and the exhaust camshaft 26 to which the rotation of the crankshaft 34 is transmitted, respectively.

The intake camshaft 16 is provided with a variable valve mechanism 17 that changes the valve timing, which is the opening / closing timing of the intake valve 15, by adjusting the relative phase of the intake camshaft 16 with respect to the crankshaft 34.

As shown in FIG. 1, the control of the internal combustion engine 10 and the control of the first MG 71 and the second MG 72 via the PCU 200 are executed by the control device 100 mounted on the vehicle 500.

The control device 100 includes a central processing unit (hereinafter referred to as a CPU) 110 and a memory 120 in which control programs and data are stored. Then, the CPU 110 executes the program stored in the memory 120 to execute various controls. Although not shown, the control device 100 is composed of a plurality of control units such as a control unit of the internal combustion engine 10 and a control unit of the PCU 200.

The control device 100 includes a crank angle sensor 80 that detects the rotation angle of the crankshaft 34, a cam angle sensor 81 that detects the phase of the intake camshaft 16, an air flow meter 82 that detects the intake air amount GA of the internal combustion engine 10, and an internal combustion engine. A water temperature sensor 83 that detects the cooling water temperature THW, which is the temperature of the cooling water of the engine 10, is connected. Further, the control device 100 includes a fuel pressure sensor 84 that detects the fuel pressure FP that is the pressure of the fuel in the fuel injection valve 31, a vehicle speed sensor 85 that detects the vehicle speed SP of the vehicle 500, and an accelerator operation amount that is the operation amount of the accelerator pedal. An accelerator position sensor 86 that detects ACCP and a temperature sensor 88 that detects the battery temperature THB, which is the temperature of the battery 78, are also connected. Then, the output signals from these various sensors are input to the control device 100. The control device 100 calculates the engine rotation speed NE based on the output signal Scr of the crank angle sensor 80, and the intake valve 15 is based on the output signal Scr of the crank angle sensor 80 and the output signal Sca of the cam angle sensor 81. Calculate the actual valve timing, which is the actual valve timing of. The control device 100 also calculates the charge rate of the battery 78 (hereinafter referred to as SOC).

Then, the control device 100 grasps the engine operating state based on the detection signals of the various sensors, and according to the grasped engine operating state, the fuel injection control of the fuel injection valve 31, the ignition timing control of the spark plug 32, and the intake air. Various engine controls such as valve timing control of the valve 15 and opening degree control of the throttle valve 14 are performed.

As the valve timing control, the control device 100 calculates the required valve timing, which is the control target value of the valve timing of the intake valve 15, based on the engine rotation speed NE, the engine load factor KL, and the like. Then, the valve timing of the intake valve 15 is controlled by controlling the drive of the variable valve mechanism 17 so that the actual valve timing becomes the required valve timing. In the present embodiment, the time when the valve timing of the intake valve 15 is the most retarded timing is set as the reference timing, and the valve timing of the intake valve 15 is represented by using the advance angle amount from this reference timing. There is.

Further, as the ignition timing control, the control device 100 calculates the required ignition timing, which is a control target value of the ignition timing, based on the engine rotation speed NE, the engine load factor KL, and the like. Then, when the rotation position of the crankshaft 34 reaches a position corresponding to the required ignition timing, the spark plug 32 is discharged with sparks to ignite the air-fuel mixture. In this embodiment, the ignition timing is represented by using the amount of advance from the reference position with reference to the compression top dead center.

Then, the control device 100 calculates the vehicle request output, which is the required value of the driving force of the vehicle 500, based on the accelerator operation amount ACCP, the vehicle speed SP, and the like. Further, the control device 100 has an engine required torque TE which is a required value of the output torque of the internal combustion engine 10 and a first MG required torque which is a required value of the power running torque or the regenerative torque of the first MG 71 based on the vehicle required output, SOC and the like. The TM1 and the second MG required torque TM2, which is a required value of the power running torque or the regenerative torque of the second MG 72, are calculated respectively. Then, the control device 100 controls the output of the internal combustion engine 10 according to the engine required torque TE, and also controls the torques of the first MG 71 and the second MG 72 according to the first MG required torque TM1 and the second MO MG required torque TM2. As a result, the torque required for running the vehicle 500 is controlled.

Further, when the engine required torque TE is "0" and the operation of the internal combustion engine 10 can be stopped, the control device 100 stops the operation of the internal combustion engine 10. Then, when the engine required torque TE exceeds "0", the control device 100 starts starting the internal combustion engine 10 which has been stopped.

Next, the start-up control performed when starting the internal combustion engine 10 while the operation is stopped will be described.
FIG. 3 shows a processing procedure of start-up control carried out by the control device 100. The series of processes shown in FIG. 3 is started when a start request is made to the internal combustion engine 10 whose operation is stopped, and the CPU 110 executes a program stored in the memory 120 of the control device 100. It is realized by doing. Further, in the following, the step number is represented by a number with "S" added at the beginning.

When this control is started, the control device 100 starts motoring (S100). This motoring is a control for rotating the crankshaft 34 of the internal combustion engine 10 in a state where combustion is stopped by the power of the first MG 71. When the motoring is started and the crankshaft 34 rotates, each cylinder of the internal combustion engine 10 Then, air will be sucked in and discharged.

Next, the control device 100 determines whether or not at least one of the following conditions (A) to (C) is satisfied (S110).
Condition (A): Current cooling water temperature THW ≤ threshold value THWref.

Condition (B): Current battery temperature THB ≤ threshold value THBref.
Condition (C): Current SOC ≤ threshold SOCRef.
The following values are preset in the threshold value THWref, the threshold value THBref, and the threshold value SOCRef.

First, in the present embodiment, basically, combustion control such as fuel injection and ignition is started after the engine rotation speed increased by motoring exceeds the resonance speed range of the internal combustion engine 10.

Here, when the cooling water temperature THW is equal to or lower than the specified temperature and the temperature of the internal combustion engine 10 is low and the friction of the internal combustion engine 10 is large, or when the temperature of the battery 78 for driving the first MG 71 is equal to or lower than the specified temperature. When the output torque of the 1MG71 is low, or when the SOC is less than the specified SOC and the driveable time of the 1st MG71 is short, the amount of electricity stored in the battery 78 before the engine rotation speed increased by motoring reaches the resonance speed range. It may be insufficient and it may be difficult for the engine rotation speed to exceed the resonance speed range. Therefore, whether or not the threshold THWref, the threshold THBref, and the threshold SOCRef may have difficulty in exceeding the resonance speed range due to the insufficient storage amount of the battery 78 described above. Each value is set so that can be appropriately determined.

Then, when it is determined that at least one of the condition (A), the condition (B), and the condition (C) is satisfied (S110: YES), the control device 100 determines that the current engine rotation speed NE is equal to or higher than the first threshold value NErefa. It is determined whether or not it is (S120). The first threshold NErefa is an engine rotation speed lower than the minimum rotation speed within the resonance speed range of the internal combustion engine 10, and the combustion operation of the air-fuel mixture can be started by starting the combustion control. The lower limit of speed is preset.

The control device 100 repeatedly executes the process of S120 until the engine rotation speed NE becomes equal to or higher than the first threshold value NErefa. Then, when the control device 100 determines that the engine rotation speed NE is equal to or higher than the first threshold value NErefa (S120: YES), the control device 100 starts fuel injection at a fuel injection amount suitable for engine start and ignition suitable for engine start. Combustion control is started by starting ignition at the timing (S190). Then, this control is terminated.

On the other hand, when it is determined in S110 that all of the conditions (A), (B), and (C) are not satisfied (S110: NO), in the control device 100, the current engine rotation speed NE is the resonance speed. It is determined whether or not the range is exceeded (S130). In this S130, when the current engine rotation speed NE is equal to or higher than a predetermined second threshold value, the control device 100 determines that the current engine rotation speed NE exceeds the resonance speed range. The second threshold value is set to an engine rotation speed higher than the maximum rotation speed within the resonance speed range of the internal combustion engine 10.

Then, the control device 100 repeatedly executes the process of S130 until the engine rotation speed NE exceeds the resonance speed range, and determines that the engine rotation speed NE exceeds the resonance speed range (S130: YES), the current engine required torque. It is determined whether or not TE is equal to or greater than the threshold TEref (S140). As this threshold value TEref, based on the engine required torque TE being equal to or higher than the threshold value TEref, it is appropriately determined that there is a request from the driver of the vehicle 500 to promptly increase the engine output at the time of starting the engine this time. The magnitude of the value is preset so that it can be done.

Then, when it is determined that the engine required torque TE is equal to or higher than the threshold value TEref (S140: YES), the control device 100 immediately starts fuel injection and ignition without executing the negative pressure securing process described later, thereby burning. The control is started (S190), and this process is terminated.

On the other hand, when it is determined in S140 that the engine required torque TE is less than the threshold value TEref (S140: NO), the control device 100 determines whether or not the fuel injection valve 31 has an oil leak (S150). .. In S150, the control device 100 executes an oil tightness determination process for determining the presence or absence of oil tightness leakage of the fuel injection valve 31. In this oil leakage determination process, a value obtained by subtracting the fuel pressure FPs detected when a start request is made from the fuel pressure FPe detected immediately after the operation of the internal combustion engine 10 is stopped, that is, the fuel pressure during the operation stop of the internal combustion engine 10. The amount of decrease in FP is calculated. Then, when the calculated reduction amount is equal to or more than the preset threshold value ΔFpref, it is determined that there is an oil leak, while when the calculated reduction amount is less than the threshold value ΔFpref, it is determined that there is no oil leakage. To do. The oil tightness determination process may be executed at another timing, for example, when a start request for the internal combustion engine 10 occurs. In this case, the control device 100 in S150 determines the result of the oil tightness determination process. get.

Then, when it is determined that there is an oil leak (S150: YES), the control device 100 starts combustion control by immediately starting fuel injection and ignition without executing the negative pressure securing process described later. (S190), this process is terminated.

On the other hand, when it is determined in S150 that there is no oil leak (S150: NO), the control device 100 changes the throttle opening, which is the opening of the throttle valve 14, to the idle opening, which is the opening during idle operation. Set (S160). In the process of S160 for setting the throttle opening to the idle opening when motoring is being performed, the specified negative pressure is in the intake pipe (for example, in the surge tank 13) downstream of the throttle valve 14 of the internal combustion engine 10. It is a negative pressure securing process that adjusts the opening degree of the throttle valve 14 so as to be in a state.

When the negative pressure securing process is started in this way, the control device 100 sets the output suppression ignition timing as the required ignition timing when starting the combustion control, and also sets the output suppression valve as the required valve timing when starting the combustion control. Set the timing (S170). The output suppression ignition timing is the ignition timing at which the engine output is the lowest in the range in which the air-fuel mixture can be burned, and is predetermined. Further, the output suppression valve timing is a valve timing at which the engine output is the lowest in the range in which the air-fuel mixture can be burned, and is predetermined. For example, in the case of this embodiment, the valve timing on the retard side within the variable range of the valve timing of the intake valve 15 is set as the output suppression valve timing.

Next, the control device 100 determines whether or not the intake pipe pressure P, which is the current pressure in the surge tank 13, is equal to or less than the threshold value Pref, that is, whether or not the above-defined negative pressure state is reached (S180). .. This threshold Pref is set to a negative pressure when the intake air amount is reduced to an extent that the starting shock that may occur due to the initial explosion generated by the start of combustion control can be kept within an allowable range. For example, in the present embodiment, the negative pressure obtained during idle operation is set. Further, the control device 100 determines that the intake pipe pressure P is equal to or less than the threshold value when the number of rotations of the crankshaft 34 after setting the throttle opening to the idle opening in S160 becomes equal to or more than a predetermined number of times. .. In addition, the intake pipe pressure P is actually measured to determine whether or not the measured value is below the threshold value Pref, or when the intake air amount GA is below the intake air amount during idle operation, the intake pipe is used. It may be determined that the pressure P is equal to or less than the threshold value Pref.

Then, the control device 100 repeatedly executes the process of S180 until it is determined that the intake pipe pressure P is equal to or less than the threshold value Pref, and when it is determined that the intake pipe pressure P is equal to or less than the threshold value Pref (S180: YES), the engine is started. Combustion control is started by starting fuel injection at a fuel injection amount suitable for the above and starting ignition at the ignition timing for suppressing output (S190). Then, the control device 100 ends this control.

Next, the operation and effect of this embodiment will be described.
(1) After the engine rotation speed NE exceeds the resonance speed range due to the execution of motoring by the first MG71, combustion control is started and the first explosion occurs. Here, when it is determined in the process of S130 shown in FIG. 3 that the engine rotation speed NE exceeds the resonance speed range, and then in the process of S150 it is determined that the fuel injection valve 31 does not leak oil. (S150: NO), the negative pressure securing process is executed in the process of S160. Then, when it is determined that the intake air amount of the internal combustion engine 10 has decreased due to the inside of the surge tank 13 being in a specified negative pressure state by executing this negative pressure securing process (S180: YES), Combustion control is started by the process of S190. Since the combustion control is started after the intake air amount is reduced in this way, the first explosion is compared with the case where the combustion control is started immediately after the engine rotation speed NE exceeds the resonance speed range. Since the engine output torque at the time of occurrence is small, it is possible to suppress the starting shock that tends to occur at the time of the first explosion.

On the other hand, if the negative pressure securing process is executed when the fuel injection valve 31 has an oil tight leak, the fuel may leak from the fuel injection valve 31 due to the secured negative pressure, and the fuel before the combustion of the air-fuel mixture occurs. If fuel leaks from the injection valve 31, the leaked fuel may be discharged into the exhaust passage 21 without being burned. In this regard, in the present embodiment, after it is determined that the engine rotation speed NE exceeds the resonance speed range in the processing of S130 shown in FIG. 3, there is an oil leak in the fuel injection valve 31 in the processing of S150. If it is determined (S150: YES), the combustion control is started in the process of S190 without executing the negative pressure securing process. Therefore, it is possible to prevent unburned fuel from being discharged into the exhaust passage 21 when the engine is started.

When there is no oil tight leakage in the fuel injection valve 31 in this way, after the engine rotation speed exceeds the resonance speed range, the combustion control is started after securing the negative pressure to suppress the starting shock. Combustion control can be started at a suitable time. Further, when the fuel injection valve 31 has an oil leak, the combustion control is promptly started after the engine rotation speed NE exceeds the resonance speed range to discharge the unburned fuel to the exhaust passage 21. Combustion control can be started at a time suitable for suppression.

(2) When at least one of the above conditions (A) to (C) is satisfied, the amount of electricity stored in the battery 78 is insufficient before the engine rotation speed increased by motoring reaches the resonance speed range. Therefore, it may be difficult for the engine rotation speed to exceed the resonance speed range. Then, when the engine rotation speed cannot actually exceed the resonance speed range, the combustion control is not started, so that the internal combustion engine 10 cannot be started.

In this regard, in the present embodiment, when it is determined in the process of S110 shown in FIG. 3 that the stored amount of the battery 78 may be insufficient before the engine rotation speed reaches the resonance speed range (S110). : YES), S120 and S190 are executed, so that the combustion control is started before the engine speed reaches the resonance speed range. Therefore, when the initial explosion occurs when the combustion control is started and then passes through the resonance speed range in the process of increasing the engine rotation speed, the internal combustion engine 10 can be started at least, although the engine vibration becomes large.

(3) After it is determined in the process of S130 shown in FIG. 3 that the engine rotation speed exceeds the resonance speed range, the engine required torque TE when starting the internal combustion engine 10 in the process of S140 is equal to or higher than the threshold TEref. If it is determined to be large (S140: YES), that is, if there is a request to promptly increase the engine output when starting the engine, combustion is performed in the process of S190 without executing the above negative pressure securing process. Control is started. Therefore, after the engine rotation speed exceeds the resonance speed range, the combustion control is started earlier than the case where the above-mentioned negative pressure securing process is executed to secure the negative pressure and then the combustion control is started. The engine output can be increased.

(4) When there is an oil leak in the fuel injection valve 31, the fuel pressure FP in the fuel injection valve 31 decreases while the operation of the internal combustion engine 10 is stopped. Therefore, the fuel pressure FP decreased during such operation stoppage. It is possible to determine the presence or absence of oil leakage based on the amount of decrease.

Therefore, in the present embodiment, in the oil tightness determination process in S150 shown in FIG. 3, the amount of decrease in fuel pressure FP (FPe-FPs) is calculated from the detected value of the sensor, and the calculated amount of decrease is equal to or greater than the threshold value ΔFPref. In this case, it is determined that there is an oil leak, so that the presence or absence of an oil leak can be appropriately determined.

(5) When the negative pressure securing process is executed in the process of S160 shown in FIG. 3, the process of S170 is executed, so that the ignition timing of the internal combustion engine 10 when the combustion control is started is output as described above. Since the ignition timing for suppression is set, the engine output when the first explosion occurs can be suppressed. Therefore, when the negative pressure securing process is executed in order to suppress the starting shock, the starting shock can be further suppressed.

(6) When the negative pressure securing process is executed in the process of S160 shown in FIG. 3, the valve timing of the intake valve 15 at the time of starting the combustion control is output as described above by executing the process of S170. Since the suppression valve timing is set, the engine output when the first explosion occurs can be suppressed. Therefore, when the negative pressure securing process is executed in order to suppress the starting shock, the starting shock can be further suppressed.

(Second Embodiment)
Next, a second embodiment of the control device for the internal combustion engine will be described with reference to FIGS. 4 and 5.

When the internal combustion engine 10 mounted on the vehicle 500 equipped with the planetary gear mechanism 40 is motorized and started by the first MG 71, the second MG required torque TM2 is set to "0 Nm" from a torque lower than "0 Nm". It may change to a torque that exceeds it. In this way, when the second MG required torque TM2 straddles "0 Nm", a rattling noise due to backlash is likely to be generated from the gear of the planetary gear mechanism 40. Here, if the output torque of the internal combustion engine 10 suddenly increases when the second MG required torque TM2 straddles "0 Nm", such rattling noise may increase.

Therefore, in the present embodiment, the control device 100 executes each of the processes shown in FIGS. 4 and 5 in order to suppress the generation of such rattling noise.
The series of processes shown in FIGS. 4 and 5 is executed when the combustion control is started in the state of S170 shown in FIG. 3, that is, the output suppression ignition timing and the output suppression valve timing are set. To.

When the process shown in FIG. 4 is started, the control device 100 determines whether or not the current second MG required torque TM2 has a torque lower than "0 Nm" (S300). Then, when it is determined that the second MG required torque TM2 is not a torque lower than "0 Nm" (S300: NO), the control device 100 ends this process.

On the other hand, when it is determined that the second MG required torque TM2 is a torque lower than "0 Nm" (S300: YES), the control device 100 determines whether or not the first explosion has occurred (S310).

Then, the control device 100 repeatedly executes the process of S310 until it is determined that the first explosion has occurred, and when it is determined that the first explosion has occurred (S310: YES), the required ignition timing after the occurrence of the first explosion is for the output suppression. It is determined whether or not the timing is on the advance side of the ignition timing (S320).

Then, when it is determined that the required ignition timing after the occurrence of the first explosion is not the timing on the advance side of the output suppression ignition timing (S320: NO), the control device 100 ends this process.
On the other hand, when it is determined that the required ignition timing after the occurrence of the first explosion is on the advance side of the output suppression ignition timing (S320: YES), the control device 100 determines the ignition timing of the internal combustion engine 10 for output suppression. Maintain at ignition timing (S330).

Next, the control device 100 determines whether or not the current second MG required torque TM2 is a torque larger than "0 Nm", that is, whether or not the current second MG required torque TM2 exceeds "0 Nm" ( S340).

Then, the control device 100 repeatedly executes the process of S340 until it is determined that the second MG required torque TM2 exceeds "0 Nm".
Next, when the control device 100 determines that the second MG required torque TM2 exceeds "0 Nm" (S340: YES), the ignition timing of the internal combustion engine 10 is set to the timing on the advance side of the output suppression ignition timing. The required ignition timing is changed to (S350), and this process is terminated.

Further, when the process shown in FIG. 5 is started, the control device 100 determines whether or not the current second MG required torque TM2 is lower than "0 Nm" (S300). Then, when it is determined that the second MG required torque TM2 is not a torque lower than "0 Nm" (S300: NO), the control device 100 ends this process.

On the other hand, when it is determined that the second MG required torque TM2 is a torque lower than "0 Nm" (S400: YES), the control device 100 determines whether or not the first explosion has occurred (S410).

Then, the control device 100 repeatedly executes the process of S410 until it is determined that the first explosion has occurred, and when it is determined that the first explosion has occurred (S410: YES), the required valve timing after the first explosion is for suppressing the output. It is determined whether or not the timing is on the advance side of the valve timing (S420).

Then, when it is determined that the required valve timing after the occurrence of the first explosion is not the timing on the advance side of the output suppression valve timing (S420: NO), the control device 100 ends this process.

On the other hand, when it is determined that the required valve timing after the first explosion occurs is the timing on the advance side of the output suppression valve timing (S420: YES), the control device 100 uses the valve timing of the intake valve 15 for output suppression. Maintain at valve timing (S430).

Next, the control device 100 determines whether or not the current second MG required torque TM2 is a torque larger than "0 Nm", that is, whether or not the current second MG required torque TM2 exceeds "0 Nm" ( S440).

Then, the control device 100 repeatedly executes the process of S440 until it is determined that the second MG required torque TM2 exceeds "0 Nm".
Next, when the control device 100 determines that the second MG required torque TM2 exceeds "0 Nm" (S440: YES), the valve timing of the intake valve 15 is set to the timing on the advance side of the output suppression valve timing. The timing is changed to the above-mentioned required valve timing (S450), and this process is terminated.

Next, the operation and effect of this embodiment will be described.
(7) In the process of S320 shown in FIG. 4, the required ignition timing after the occurrence of the first explosion is determined to be the timing on the advance angle side of the output suppression ignition timing (S320: YES). When the engine output is increased by setting the ignition timing, the processes of S330, S340, and S350 are executed. As a result, the change of the ignition timing from the output suppression ignition timing to the required ignition timing is suspended until the second MG required torque TM2 exceeds "0 Nm". Therefore, the sudden increase in the output torque of the internal combustion engine 10 when the second MG required torque TM2 straddles "0 Nm" is suppressed, and thereby the rattling noise generated from the planetary gear mechanism 40 can be suppressed.

(8) In the process of S420 shown in FIG. 5, it is determined that the required valve timing after the occurrence of the first explosion is the timing on the advance angle side of the output suppression valve timing (S420: YES). When the engine output is increased by setting the valve timing, the processes of S430, S440 and S450 are executed. As a result, the change of the valve timing from the output suppression valve timing to the required valve timing is suspended until the second MG required torque TM2 exceeds "0 Nm". Therefore, a rapid increase in the output torque of the internal combustion engine 10 when the second MG required torque TM2 straddles "0 Nm" is suppressed, and this also suppresses the rattling noise generated from the planetary gear mechanism 40.

(Third Embodiment)
Next, a third embodiment of the control device for the internal combustion engine will be described with reference to FIGS. 6 and 7.

In the second embodiment, the output is suppressed until the second MG required torque TM2 exceeds "0 Nm" in order to suppress the rattling noise generated from the planetary gear mechanism 40 when the second MG required torque TM2 straddles "0 Nm". The change of ignition timing from the ignition timing for use to the required ignition timing is suspended. Further, the change of the valve timing from the output suppression valve timing to the above-mentioned required valve timing is suspended until the second MG required torque TM2 exceeds "0 Nm".

On the other hand, in the present embodiment, the generation of the rattling noise is suppressed by executing the processes of S500 and S510 described later instead of the processes of S330 and S350 described in FIG. Further, in the present embodiment, the generation of the tooth-beating sound is suppressed by executing the processes of S600 and S610 described later instead of the processes of S430 and S450 described with reference to FIG.

Hereinafter, the present embodiment will be described with a focus on the differences from the second embodiment.
FIG. 6 shows a processing procedure in which a part of the series of processing shown in FIG. 4 is changed, and the same processing as each processing shown in FIG. 4 is assigned the same step number. Further, the series of processes shown in FIG. 6 is also executed when the process of S170 shown in FIG. 3, that is, when the combustion control is started in a state where the output suppression ignition timing and the output suppression valve timing are set.

When this process is started, the control device 100 sequentially executes each of the processes of S300, S310, and S320 described above. Then, in the process of S320, when it is determined that the required ignition timing after the occurrence of the first explosion is the timing on the advance angle side of the output suppression ignition timing (S320: YES), the control device 100 is the internal combustion engine 10. The ignition timing is changed by the first rate of change HT1 (S500). The first change rate HT1 is the change rate of the ignition timing in the process of changing the ignition timing of the internal combustion engine 10 from the output suppression ignition timing to the required ignition timing, and is smaller than the second change rate HT2 described later. It is a value. Further, an optimum value is set for the first rate of change HT1 in order to suppress the generation of rattling noise from the planetary gear mechanism 40.

Next, the control device 100 determines whether or not the current second MG required torque TM2 exceeds "0 Nm" (S340).
Then, when it is determined that the second MG required torque TM2 exceeds "0 Nm" (S340: YES), the control device 100 changes the ignition timing of the internal combustion engine 10 at the second rate of change HT2 (S510). This second rate of change HT2 is also the rate of change of the ignition timing in the process of changing the ignition timing of the internal combustion engine 10 from the output suppression ignition timing to the above-mentioned required ignition timing, and is a value larger than the first rate of change HT1. It has become. Further, the second rate of change HT2 is set to a value capable of changing the ignition timing to the required ignition timing as soon as possible while suppressing the occurrence of torque shock due to a rapid increase in engine output. Then, the control device 100 ends this process.

Further, FIG. 7 shows a processing procedure in which a part of the series of processing shown in FIG. 5 is changed, and the same processing as each processing shown in FIG. 5 is assigned the same step number. Further, the series of processes shown in FIG. 7 is also executed when the combustion control is started in the state of S170 shown in FIG. 3, that is, the output suppression ignition timing and the output suppression valve timing are set.

When this process is started, the control device 100 sequentially executes each process of S400, S410, and S420 described above. Then, in the process of S420, when it is determined that the required valve timing after the occurrence of the first explosion is the timing on the advance side of the output suppression valve timing (S420: YES), the control device 100 determines that the intake valve 15 The valve timing is changed at the first rate of change HV1 (S600). The first rate of change HV1 is the rate of change of the valve timing in the process of changing the valve timing from the output suppression valve timing to the above-mentioned required valve timing, and is smaller than the second rate of change HV2 described later. There is. Further, an optimum value is set for the first rate of change HV1 in order to suppress the generation of rattling noise from the planetary gear mechanism 40.

Next, the control device 100 determines whether or not the current second MG required torque TM2 exceeds "0 Nm" (S440).
Then, when it is determined that the second MG required torque TM2 exceeds "0 Nm" (S440: YES), the control device 100 changes the valve timing of the intake valve 15 at the second rate of change HV2 (S610). This second rate of change HT2 is also the rate of change of the valve timing in the process of changing the valve timing from the output suppression valve timing to the above-mentioned required valve timing, and is a value larger than the above-mentioned first rate of change HV1. .. Further, the second rate of change HV2 is set to a value at which the valve timing can be changed to the required valve timing as soon as possible while suppressing the occurrence of torque shock due to a rapid increase in engine output. Then, the control device 100 ends this process.

Next, the operation and effect of this embodiment will be described.
(9) In the process of S320 shown in FIG. 6, the required ignition timing after the occurrence of the first explosion is determined to be the timing on the advance angle side of the output suppression ignition timing (S320: YES). When the engine output is increased by setting the ignition timing, the processes of S500, S340 and S510 are executed. As a result, until the second MG required torque TM2 exceeds "0 Nm", the rate of change of the ignition timing in the process of changing the ignition timing from the output suppression ignition timing to the required ignition timing becomes the first change rate HT1. By setting, the rate of change in ignition timing becomes small and the increase in output torque of the internal combustion engine 10 becomes gradual. Therefore, the sudden increase in the output torque of the internal combustion engine 10 when the second MG required torque TM2 straddles "0 Nm" is suppressed, and thereby the rattling noise generated from the planetary gear mechanism 40 can be suppressed.

(10) In the process of S420 shown in FIG. 7, it is determined that the required valve timing after the occurrence of the first explosion is the timing on the advance angle side of the output suppression valve timing (S320: YES). When the engine output is increased by setting the valve timing, the processes of S500, S340 and S510 are executed. As a result, until the second MG required torque TM2 exceeds "0 Nm", the rate of change of the valve timing in the process of changing the valve timing from the output suppression valve timing to the required valve timing becomes the first change rate HV1. By setting, the rate of change in valve timing becomes small, and the increase in output torque of the internal combustion engine 10 becomes gradual. Therefore, a rapid increase in the output torque of the internal combustion engine 10 when the second MG required torque TM2 straddles "0 Nm" is suppressed, and this also suppresses the rattling noise generated from the planetary gear mechanism 40.

Each of the above embodiments can be modified and implemented as follows. Each of the above embodiments and the following modified examples can be implemented in combination with each other within a technically consistent range.

In the oil tightness determination process in S150 of FIG. 3, the presence or absence of oil tightness leakage was determined based on the amount of decrease in the fuel pressure FP when the operation of the internal combustion engine 10 was stopped, but instead of the process of S150 The oil tightness determination process shown in S700 of FIG. 8 may be executed.

The oil tightness determination process in S700 of FIG. 8 is a process of determining that there is an oil tightness leak when the operation stop time TS of the internal combustion engine 10 before starting is equal to or greater than the specified threshold value TSref. As the threshold value TSref, the internal combustion engine 10 is stopped for a long time to some extent that there is a possibility that an unacceptable amount of fuel is leaking from the fuel injection valve 31 based on the operation stop time TS being equal to or higher than this threshold value TSref. The magnitude of the value is preset so that it can be appropriately determined what has been done. For example, as the threshold value TSref, a time of about several hours is set.

According to such a modified example, the following effects can be obtained. That is, when the fuel injection valve 31 has an oil leak, the fuel gradually leaks from the fuel injection valve 31 while the operation of the internal combustion engine 10 is stopped. Therefore, the longer the operation stop time TS, the larger the leakage amount. .. If motoring is performed in a state where the amount of leakage is large in this way, unburned fuel may be discharged to the exhaust passage 21 until combustion is started. Therefore, if the combustion control is started as early as possible when the amount of fuel leak is large and the leaked fuel is burned at an early stage, the amount of unburned fuel discharged to the exhaust passage 21 can be suppressed. .. In this regard, in the above modified example, as the oil tightness determination process in S700, when the operation stop time TS is equal to or greater than the threshold value TSref, a process of determining that there is an oil tightness leak is executed. Therefore, when the operation stop time TS is equal to or greater than the threshold value TSref and there is a possibility that the amount of fuel leaked from the fuel injection valve 31 is large, it is determined that there is an oil leak (S700: YES). ), When starting the engine, the combustion control is promptly started by executing the process of S190 without executing the above-mentioned negative pressure securing process after S160. Therefore, even if the fuel injection valve 31 has an oil leak, the amount of unburned fuel discharged to the exhaust passage 21 can be suppressed.

-In the second embodiment, the series of processes shown in FIGS. 4 and 5 is executed, but only the series of processes shown in FIG. 4 may be executed, or only the series of processes shown in FIG. 5 may be executed. ..
-In the third embodiment, the series of processes shown in FIGS. 6 and 7 is executed, but only the series of processes shown in FIG. 6 may be executed, or only the series of processes shown in FIG. 7 may be executed. ..

-Instead of executing the series of processes shown in FIG. 4 in the second embodiment, the series of processes shown in FIG. 6 may be executed in the third embodiment.
-Instead of executing the series of processes shown in FIG. 5 in the second embodiment, the series of processes shown in FIG. 7 may be executed in the third embodiment.

The fuel injection valve 31 may be an in-cylinder injection type fuel injection valve that directly injects fuel into the cylinder of the internal combustion engine 10.
-The vehicle to which the first embodiment is applied is not limited to a hybrid vehicle, and may be a vehicle having only an internal combustion engine as a vehicle prime mover and having an electric motor for motorizing the internal combustion engine.

The control device 100 includes a CPU 110 and a memory 120, and is not limited to the one that executes software processing. For example, a dedicated hardware circuit (for example, ASIC or the like) that processes at least a part of the software processing executed in each of the above embodiments may be provided. That is, the control device 100 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 memory for storing the program are provided. (B) A processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing are provided. (C) A dedicated hardware circuit for executing all of the above processes is provided. Here, there may be a plurality of software processing circuits including a processing device and a program storage device, and a plurality of dedicated hardware circuits. That is, the processing may be executed by a processing circuit including at least one of one or more software processing circuits and one or more dedicated hardware circuits.

10 ... Internal combustion engine, 11 ... Intake passage, 12 ... Intake port, 13 ... Surge tank, 14 ... Throttle valve, 15 ... Intake valve, 16 ... Intake camshaft, 17 ... Variable valve mechanism, 21 ... Exhaust passage, 22 ... Exhaust port, 25 ... Exhaust valve, 26 ... Exhaust camshaft, 30 ... Combustion chamber, 31 ... Fuel injection valve, 32 ... Ignition plug, 33 ... Piston, 34 ... Crankshaft, 40 ... Planetary gear mechanism, 41 ... Sun gear, 42 ... Ring gear, 44 ... Carrier, 50 ... Reduction mechanism, 60 ... Drive shaft, 61 ... Differential gear, 62 ... Drive wheels, 71 ... 1st motor generator (1st MG), 72 ... 2nd motor generator (2nd MG), 78 ... Battery, 80 ... Crank angle sensor, 81 ... Cam angle sensor, 82 ... Air flow meter, 83 ... Water temperature sensor, 84 ... Fuel pressure sensor, 85 ... Vehicle speed sensor, 86 ... Accelerator position sensor, 88 ... Temperature sensor, 100 ... Control device , 110 ... Central processing device (CPU), 120 ... Memory, 200 ... PCU, 500 ... Vehicle.

Claims (11)

A control device applied to an internal combustion engine that is motorized by an electric motor when there is a start request.
While executing the oil tightness determination process for determining the presence or absence of oil tightness leakage of the fuel injection valve provided in the internal combustion engine,
If it is determined that there is no oil leakage, the throttle of the internal combustion engine is increased after the engine rotation speed of the internal combustion engine, which is increased by executing the motoring in accordance with the start request, exceeds the resonance speed range of the internal combustion engine. A negative pressure securing process for adjusting the opening degree of the throttle valve is executed so that the inside of the intake pipe downstream of the valve is in the specified negative pressure state, and the inside of the intake pipe is in the negative pressure state by executing the negative pressure securing process. When it is determined that there is an oil-tight leak, the engine rotation speed of the internal combustion engine, which is increased by the execution of the motoring in accordance with the start request, is increased while the combustion control of the internal combustion engine is started. A control device for an internal combustion engine that executes start-up control that starts combustion control of the internal combustion engine without executing the negative pressure securing process after exceeding the resonance speed range. In the start-up control, the condition that the temperature of the internal combustion engine is equal to or lower than the specified temperature, the condition that the temperature of the battery that drives the electric motor is equal to or lower than the specified temperature, and the charge rate of the battery are specified charging. If at least one of the conditions of being less than or equal to the rate is satisfied, the combustion of the internal combustion engine before the engine rotation speed of the internal combustion engine, which is increased by the execution of the motoring according to the start request, reaches the resonance speed range. The control device for an internal combustion engine according to claim 1, wherein the process of initiating control is executed. In the start-up control, when the internal combustion engine is started, if the required value of the output torque of the internal combustion engine is equal to or more than a specified value, the engine rotation of the internal combustion engine is increased by executing the motoring in accordance with the start request. The control device for an internal combustion engine according to claim 1 or 2, wherein after the speed exceeds the resonance speed range, a process for starting combustion control of the internal combustion engine is executed without executing the negative pressure securing process. The internal combustion engine includes a sensor that detects the fuel pressure in the fuel injection valve.
The oil-tightness determination process calculates the amount of decrease in fuel pressure that has decreased while the internal combustion engine is stopped from the detected value of the sensor, and when the calculated amount of decrease is equal to or greater than a specified determination value, the oil-tightness is determined. The control device for an internal combustion engine according to any one of claims 1 to 3, which executes a process for determining that there is a leak. The oil-tightness determination process according to any one of claims 1 to 3 for executing the process of determining that there is an oil-tightness leak when the operation stop time of the internal combustion engine before starting is equal to or longer than a specified determination value. The control device for an internal combustion engine described. When the negative pressure securing process is executed, the ignition timing of the internal combustion engine when the combustion control is started is for output suppression, which is the ignition timing at which the engine output becomes the lowest within the range in which the air-fuel mixture can be burned. The control device for an internal combustion engine according to any one of claims 1 to 5, which executes a process of setting an ignition timing. When the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine uses the output of the internal combustion engine as the first electric motor. It is connected to the planetary gear mechanism that distributes to the output shaft and the drive shaft.
The required value of the output torque of the second motor when the combustion control is started is a torque lower than "0 Nm", and the required ignition timing after the first explosion occurs is on the advance side of the output suppression ignition timing. If it is the timing, a process of suspending the change of the ignition timing from the output suppression ignition timing to the required ignition timing is executed until the required value of the output torque of the second electric motor exceeds "0 Nm". Item 6. The control device for an internal combustion engine according to Item 6. When the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine uses the output of the internal combustion engine as the first electric motor. It is connected to the planetary gear mechanism that distributes to the output shaft and the drive shaft.
The required value of the output torque of the second motor when the combustion control is started is a torque lower than "0 Nm", and the required ignition timing after the first explosion occurs is on the advance side of the output suppression ignition timing. When it is the timing, it is the rate of change of the ignition timing in the process of changing the ignition timing from the output suppression ignition timing to the required ignition timing, and the required value of the output torque of the second motor is "0 Nm". The control device for an internal combustion engine according to claim 6, wherein the process of reducing the rate of change until the rate exceeds the rate of change after the required value of the output torque of the second electric motor exceeds "0 Nm" is made smaller than the rate of change. The internal combustion engine is provided with a variable valve mechanism that changes the valve timing of the intake valve.
When the negative pressure securing process is executed, the valve timing at the time of starting the combustion control is set to the output suppression valve timing, which is the valve timing at which the engine output becomes the lowest in the range where the air-fuel mixture can be burned. The control device for an internal combustion engine according to any one of claims 1 to 6, which executes the process of setting. When the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine uses the output of the internal combustion engine as the first electric motor. It is connected to the power distribution mechanism that distributes to the output shaft and the drive shaft.
The required value of the output torque of the second electric motor when the combustion control is started is a torque lower than "0 Nm", and the required valve timing after the occurrence of the first explosion is on the advance side of the output suppression valve timing. In the case of timing, a process of suspending the change of the valve timing from the output suppression valve timing to the required valve timing is executed until the required value of the output torque of the second electric motor exceeds "0 Nm". Item 9. The control device for an internal combustion engine according to Item 9. When the electric motor is the first electric motor and the electric motor that transmits power to the drive shafts connected to the drive wheels of the vehicle is the second electric motor, the output shaft of the internal combustion engine uses the output of the internal combustion engine as the first electric motor. It is connected to the planetary gear mechanism that distributes to the output shaft and the drive shaft.
The required value of the output torque of the second electric motor when the combustion control is started is a torque lower than "0 Nm", and the required valve timing after the occurrence of the first explosion is on the advance side of the output suppression valve timing. In the case of timing, it is the rate of change of valve timing in the process of changing the valve timing from the output suppression valve timing to the required valve timing, and the required value of the output torque of the second motor is "0 Nm". The control device for an internal combustion engine according to claim 9, wherein the process of reducing the rate of change until the rate exceeds "0 Nm" is made smaller than the rate of change after the required value of the output torque of the second electric motor exceeds "0 Nm".