JP2020197200A - Internal combustion engine control apparatus - Google Patents

Abstract

To provide an internal combustion engine control apparatus that stabilizes the combustion of air-fuel mixture at starting of an engine.SOLUTION: An internal combustion engine 10 includes: an intake valve 15 for opening and closing an intake port 12 provided for each of plural cylinders; and a fuel injection valve 31 for injecting fuel into the intake port 12. A control apparatus 100 executes an at-start increase amount in which a fuel injection amount is increased by a specified increase amount at starting of the engine. As regards a total amount of increase amount of a fuel injection amount during the execution of the at-start increase amount, the control apparatus 100 performs total amount adjustment processing in which a total amount in a cylinder where the intake valve 15 has been closed during an operation stop before starting the engine is made larger than a total amount in a cylinder where the intake valve 15 has been open during an operation stop.SELECTED DRAWING: Figure 1

Description

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

In an internal combustion engine, a start-up increase is executed in which the fuel injection amount is increased by a specified increase value at the start of the engine (for example, Patent Document 1).

JP-A-2015-48722

The increase in the fuel injection amount due to the increase at the start time is set according to the amount of fuel adhering to the temperature of the intake port and the intake valve. Since the amount of such fuel adhered decreases as the temperature of the intake port and the intake valve increases, the total amount of the increase in the fuel injection amount during the increase at the start time decreases as the temperature of the intake port and the intake valve increases.

Here, in an internal combustion engine having a plurality of cylinders, the temperature of the intake port at the start of engine start is substantially the same in each cylinder, but the temperature of the intake valve may differ for each cylinder. Therefore, if the total amount of the increase in the fuel injection amount during the start-up increase is made uniform in each cylinder without considering the difference in the amount of fuel adhered due to the temperature difference of the intake valve, the combustion chamber of each cylinder Since the amount of fuel supplied to the fuel is excessive or insufficient, it may be in an unfavorable state from the viewpoint of stabilizing the combustion of the air-fuel mixture.

An internal combustion engine control device for solving the above problems is applied to an internal combustion engine including an intake valve for opening and closing an intake port provided in each of a plurality of cylinders and a fuel injection valve for injecting fuel into the intake port. Then, the fuel injection amount is increased at the specified increase value at the start of the engine to execute the start-up increase. This control device stops the operation of the total amount of the cylinders whose intake valves were closed during the operation stop before the engine start, with respect to the total amount of the increase in the fuel injection amount during the execution of the increase at the start. A total amount adjustment process is performed in which the intake valve is made larger than the total amount of the cylinders in which the valve is open.

Since the opening / closing operation of the intake valve is stopped during the operation stop before the engine is started, in an internal combustion engine having a plurality of cylinders, the intake valve is stopped in the open state during the operation stop. , There is a cylinder that is stopped while the valve is closed. Here, the intake valve that is in the closed state during the operation stop is in the open state during the operation stop because its umbrella portion is seated at the opening of the intake port provided in the cylinder head. The temperature is more likely to drop than the intake valve. Therefore, the temperature at the start of engine start of the intake valve that was in the closed state during the shutdown is lower than the temperature at the start of the engine start of the intake valve that was in the open state during the shutdown. ..

Therefore, when fuel injection is performed when the engine is started, the amount of fuel adhering to the intake valve that was in the valve closed state during the shutdown is the fuel that adheres to the intake valve that was in the valve open state during the shutdown. More than the amount of.

Therefore, in the same configuration, by executing the above total amount adjustment process, the intake valve opens the total amount of the increase in the fuel injection amount in the cylinder in which the intake valve was closed during the operation stop. The amount is made larger than the total amount of the increase in the fuel injection amount in the cylinder that was in the valve state. Therefore, the total amount of the increased fuel injection amount is adjusted for each cylinder according to the amount of fuel adhering to the intake valve when the engine is started, and the fuel supplied to the combustion chamber of each cylinder is thereby adjusted. Since the excess or deficiency of the amount of fuel can be suppressed, the combustion of the air-fuel mixture becomes stable when the engine is started.

In the control device, the total amount adjustment process may be performed to increase the total amount of each cylinder as the operation stop time, which is the time during which the internal combustion engine was stopped before the engine is started, is longer.

The longer the internal combustion engine is stopped, the lower the temperature of the intake valve. Therefore, the longer the operation stop time before starting the engine, the lower the temperature of the intake valve at the start of the engine start, and the larger the amount of fuel adhering to the intake valve at the start of the engine.

In this respect, in the same configuration, the longer the operation stop time and the larger the amount of fuel adhering to the intake valve at the time of starting the engine, the larger the total amount of the increased fuel injection amount. Therefore, the excess or deficiency of the amount of fuel supplied to the combustion chamber of each cylinder can be further suppressed, and the combustion of the air-fuel mixture becomes more stable when the engine is started.

In the control device, the total amount adjusting process may be performed to increase the total amount of each cylinder as the cooling water temperature of the internal combustion engine at the start of engine start becomes lower.
The lower the cooling water temperature at the start of engine start, the lower the temperature of the intake valve, and the larger the amount of fuel adhering to the intake valve at the start of engine start.

In this respect, in the same configuration, the lower the cooling water temperature at the start of engine start and the larger the amount of fuel adhering to the intake valve at the start of engine start, the larger the total amount of the increased fuel injection amount. Therefore, the excess or deficiency of the amount of fuel supplied to the combustion chamber of each cylinder can be further suppressed, and the combustion of the air-fuel mixture becomes more stable when the engine is started.

In the control device, the operation is stopped based on the operation stop time of the internal combustion engine before the engine is started, the cooling water temperature of the internal combustion engine during the operation stop, and the state of the intake valve in each cylinder during the operation stop. In addition to executing the valve temperature estimation process for calculating the temperature of the intake valve of each cylinder inside, in the valve temperature estimation process, the temperature of the intake valve that is in the closed state during the operation stop is the operation stop. The process of calculating the temperature so as to be lower than the temperature of the intake valve which is in the open state is executed, and the total amount adjustment process is performed on the cylinder whose temperature of the intake valve which is stopped is low. The total amount may be increased by increasing the total amount of the cylinder having a high temperature of the intake valve during the shutdown.

The longer the shutdown time of the internal combustion engine or the lower the cooling water temperature of the internal combustion engine during the shutdown, the lower the temperature of the intake valve of each cylinder during the shutdown. Further, the temperature of the intake valve during the stoppage differs depending on the state of the intake valve in each cylinder during the shutdown. That is, the temperature of the intake valve that is closed while the operation is stopped is lower than that of the intake valve that is open. Therefore, in the same configuration, the estimated value of the temperature of the intake valve of each cylinder during the operation stop is calculated by executing the valve temperature estimation process.

Here, since the temperature of the intake valve whose temperature is low while the operation is stopped is also low at the start of engine start, the amount of fuel adhering to the engine start is large. Therefore, in the same configuration, the total amount of the increased fuel injection amount of the cylinder with the low temperature of the intake valve is larger than the total amount of the increase of the fuel injection amount of the cylinder with the high temperature. Therefore, even with the same configuration, the total amount of the increased fuel injection amount is adjusted for each cylinder according to the amount of fuel adhering to the intake valve when the engine is started, and this causes the combustion chamber of each cylinder to be adjusted. Since the excess or deficiency of the amount of fuel supplied can be suppressed, the combustion of the air-fuel mixture becomes stable when the engine is started.

As a process for increasing the total amount of the fuel injection amount increased due to the increase at the start time, a process for increasing the total amount by increasing the increase value can be adopted.
Further, when the process of attenuating the increase value and ending the increase at the start is executed when the specified attenuation start time elapses after the increase at the start is started, the increase in the fuel injection amount due to the increase at the start is executed. As a process for increasing the total amount, a process for increasing the total amount can be adopted by lengthening the attenuation start time.

In addition, when the process of attenuating the increase value at a specified damping rate to end the increase at start is executed after the increase at start is started, the total amount of the increase in fuel injection amount due to the increase at start is used. As a process for increasing the amount, a process for increasing the total amount by slowing the attenuation rate can be adopted.

In the control device, the internal combustion engine is mounted on a vehicle equipped with an internal combustion engine and an electric motor as a prime mover, and a catalyst for purifying exhaust gas is provided in an exhaust passage of the internal combustion engine at the time of starting. When a request to stop the operation of the internal combustion engine occurs during the execution of the increase in the amount, a stop delay process for delaying the stop of the operation of the internal combustion engine is executed until the atmosphere of the catalyst becomes stoichiometric, and the request to stop the operation is executed. When the vehicle speed of the vehicle is equal to or less than a predetermined threshold value, a process of stopping the operation of the internal combustion engine may be executed without executing the stop delay process.

The atmosphere of the catalyst is rich during the start-up increase, and if the operation of the internal combustion engine is stopped in this rich state, the exhaust purification capacity of the catalyst temporarily decreases at the next engine start. There is a risk of Therefore, in the same configuration, when a request to stop the operation of the internal combustion engine occurs during the execution of the increase in the amount at the time of starting, a stop delay process for delaying the operation stop of the internal combustion engine is executed until the atmosphere of the catalyst becomes stoichiometric. This suppresses such a decrease in exhaust purification capacity. Here, in a vehicle equipped with an internal combustion engine and an electric motor as a prime mover, a so-called hybrid vehicle, the fuel efficiency is improved by stopping the operation of the internal combustion engine, etc., but the above stop delay process is executed and the operation of the internal combustion engine is stopped. If it is delayed, the fuel efficiency will deteriorate accordingly. In this respect, in the same configuration, when the vehicle speed when the operation stop request is generated is equal to or less than the specified threshold value, the operation of the internal combustion engine is stopped without executing the stop delay process. Therefore, in a situation where the vehicle speed is equal to or less than the specified threshold value, it is possible to suppress the deterioration of fuel efficiency due to the execution of the stop delay process.

In the control device, the internal combustion engine includes a sensor that detects the atmosphere of the catalyst, and the stop delay process determines whether or not the atmosphere of the catalyst is in a stoichiometric state based on the detection value of the sensor. On the other hand, if it is not possible to determine the atmosphere of the catalyst based on the detected value of the sensor, the integrated air amount which is the integrated value of the amount of air sucked into the internal combustion engine after the increase at the start time is completed. May be executed after the temperature becomes equal to or higher than the specified air amount threshold value to stop the operation of the internal combustion engine.

Based on the detection value of a sensor that detects the atmosphere of the catalyst, for example, a sensor that detects the oxygen concentration of the exhaust gas that has passed through the catalyst, it is possible to determine whether or not the atmosphere of the catalyst is in a stoichiometric state. However, if it is not possible to determine whether or not the atmosphere of the catalyst is in a stoichiometric state based on the detected value of the sensor, the above stop delay process cannot be executed. Therefore, in the same configuration, when it is not possible to determine the atmosphere of the catalyst based on the sensor detection value, the integrated air amount, which is the integrated value of the amount of air sucked into the internal combustion engine after the start-up increase is completed, is specified. The operation of the internal combustion engine is stopped when it can be estimated that the atmosphere of the catalyst is in a stoichiometric state because the air amount is equal to or higher than the threshold value. Therefore, even when it is impossible to determine the atmosphere of the catalyst based on the detection value of the sensor, the stop delay process can be executed.

In the control device, the air amount threshold value may be variably set so that the larger the total amount, the larger the value.
The larger the total amount of the increase in the fuel injection amount due to the increase at the start time, the larger the integrated air amount required for the atmosphere of the catalyst to become stoichiometric. In this regard, in the same configuration, the air amount threshold value is variably set so that the larger the total amount, the larger the value. Therefore, even if the total amount is different, it is determined whether or not the atmosphere of the catalyst is in a stoichiometric state. Can be done properly.

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 flowchart which shows the procedure of the valve temperature estimation processing executed by the control device of the same embodiment. The conceptual diagram which shows the estimation mode of a valve temperature. The flowchart which shows the procedure of the port temperature estimation process executed by the control device of the same embodiment. The conceptual diagram which shows the estimation mode of a port temperature. The flowchart which shows the procedure of the total amount adjustment processing executed by the control device of the same embodiment. The graph which shows the setting mode of the increase value set according to a valve temperature and a port temperature. The graph which shows the setting mode of the attenuation start time set according to a valve temperature and a port temperature. The graph which shows the setting mode of the damping rate set according to a valve temperature and a port temperature. The flowchart which shows the procedure of the total amount adjustment processing executed by the control apparatus of 2nd Embodiment. The conceptual diagram which shows the setting mode of the increase value in the same embodiment. The conceptual diagram which shows the setting mode of the attenuation start time in the same embodiment. The conceptual diagram which shows the setting mode of the attenuation rate in the same embodiment. The flowchart which shows the procedure of the valve temperature estimation processing executed by the control device of 3rd Embodiment. The conceptual diagram which shows the estimation mode of the average value of the valve temperature in the same embodiment. The flowchart which shows the procedure of the process which the control device of 4th Embodiment executes. The conceptual diagram which shows the setting mode of the air amount threshold value in the same embodiment. The schematic diagram which shows the state of the throttle valve in an intake passage. The flowchart which shows the procedure of the target opening degree setting process which a control device executes in the modification of each embodiment. The flowchart which shows the procedure of the speed-up process which a control device executes in the modification of each embodiment. The flowchart which shows the procedure of the speed-up process which a control device executes in the modification of each embodiment. The flowchart which shows the procedure of the speed-up process which a control device executes in the modification of each 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 9.

As shown in FIG. 1, the vehicle 500 is a hybrid vehicle including an internal combustion engine 10 having a plurality of cylinders and an electric motor as a prime mover, and the electric motor is described as a first motor generator (hereinafter referred to as a first MG) which is a first electric motor. A second motor generator (hereinafter referred to as a second MG) 72, which is a second electric motor, is provided.

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.

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 formed in the cylinder head 10H, and is injected from the fuel injection valve 31 into the intake port 12. 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 discharged from the combustion chamber 30 to the exhaust passage 21 via the exhaust port 22 formed in the cylinder head 10H. The exhaust passage 21 is provided with a three-way catalyst (hereinafter referred to as a catalyst) 23 for purifying the exhaust gas which is the air-fuel mixture after combustion.

A front sensor 88 is provided in a portion upstream of the catalyst 23 in the exhaust passage 21, and a rear sensor 89 is provided in a portion downstream of the catalyst 23 in the exhaust passage 21. The front sensor 88 outputs a signal AFf according to the air-fuel ratio of the exhaust gas flowing into the catalyst 23. The rear sensor 89 outputs a signal AFr according to the oxygen concentration of the exhaust gas that has passed through the catalyst 23.

The intake passage 11 is provided with a throttle valve 14 for adjusting the intake air amount. The opening degree of the throttle valve 14 is adjusted by an electric motor. A water jacket 14w through which cooling water for an internal combustion engine flows is provided around the throttle valve 14.

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 hydraulic 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.

The internal combustion engine 10 includes an oil pump 90 that is rotationally driven by a crankshaft 34, and the variable valve mechanism 17 is driven by using the pressure of the hydraulic oil that is sent from the oil pump 90.

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 control device 100 executes various control-related processes by the CPU 110 executing the program stored in the memory 120. 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.

A crank angle sensor 80 that detects the crank angle of the crankshaft 34 is connected to the control device 100. The crank angle sensor 80 includes an element capable of detecting the crank angle until the engine rotation speed becomes "0" when the engine is stopped, for example, a Hall element. Further, the control device 100 includes 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 a cooling water temperature THW that is the temperature of the cooling water of the internal combustion engine 10. A water temperature sensor 83 for detecting the above is connected. Further, the control device 100 includes an outside temperature sensor 84 that detects the outside temperature THout, a vehicle speed sensor 85 that detects the vehicle speed SP of the vehicle 500, and an accelerator position sensor 86 that detects the accelerator operation amount ACCP, which is the operation amount of the accelerator pedal. A pressure sensor 87 that detects the oil pressure PR, which is the pressure of the hydraulic oil sent from the oil pump 90, is connected. Further, the front sensor 88 and the rear sensor 89 are also connected to the control device 100. 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. The variable valve mechanism 17 is driven by utilizing the pressure of the hydraulic oil sent from the oil pump 90. Therefore, when the hydraulic PR is equal to or higher than the specified threshold value PRref, the control device 100 drives the variable valve mechanism 17. By the way, as the threshold value PRref, the minimum oil pressure required to properly drive the variable valve mechanism 17 is set.

Further, the control device 100 calculates the engine required torque TE, which is the required value of the output torque of the internal combustion engine 10, as the opening degree control of the throttle valve 14. Then, the required air amount GAD required to obtain the engine required torque TE is calculated, and the target opening degree TAp, which is the opening degree of the throttle valve 14 required to obtain the calculated required air amount GAD, is calculated. Then, the actual opening degree of the throttle valve 14 is controlled so as to have this target opening degree TAp.

Further, as the fuel injection control, the control device 100 calculates the basic injection amount, which is the basic value of the fuel amount injected from the fuel injection valve 31, based on the intake air amount GA, the engine rotation speed NE, and the like. Then, the final injection amount is calculated by correcting the basic injection amount according to the engine operating state, and the drive control of the fuel injection valve 31 is performed so that the final injection amount is injected.

The control device 100 executes an increase at the time of starting as one of the corrections of the basic injection amount according to the engine operating state. This increase at the start is carried out at the start of the engine start for the purpose of stabilizing the combustion state of the air-fuel mixture at the start of the engine. That is, the fuel injection amount of the fuel injection valve 31 is increased in order to compensate for the shortage of the amount of fuel supplied to the combustion chamber 30 due to the adhesion of fuel to the intake port 12 and the intake valve 15 when the engine is started. It is basically carried out as follows.

When this start-up increase is started, first, a process of increasing the basic injection amount at a specified increase value Z is performed to increase the fuel injection amount. Then, when the specified attenuation start time DECT elapses after the start-up increase is started, the start-up increase is terminated by attenuating the increase value Z at the specified attenuation speed DECT. The setting of the increase value Z, the attenuation start time DECT, and the attenuation speed DECT will be described later.

Further, it is a value determined by the increase value Z, the damping start time DECT, and the damping speed DECT, and is the total amount of the increase in the fuel injection amount during the execution of the start-up increase, that is, from the start to the end of the start-up increase. The total amount of the increase in the fuel injection amount increased by the increase value Z in between is simply referred to as the total amount ZT below.

By the way, the larger the increase value Z is and the larger the increase in the fuel injection amount per unit time is, or the longer the attenuation start time DECT is and the later the attenuation start time of the increase value Z is, or the more the attenuation rate DECS The slower the fuel increase per unit time and the smaller the decrease, the larger the total amount ZT. Therefore, when the temperature of the intake port 12 and the intake valve 15 is low at the start of engine start and the amount of fuel adhering to the intake port 12 and the intake valve 15 is large, the amount of fuel supplied to the combustion chamber 30 is increased. In order to make up for the shortage, the total amount ZT is set to a large amount.

Then, the control device 100 calculates the vehicle required 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 requests the engine required torque TE, which is the required value of the output torque of the internal combustion engine 10, and the first MG request, which is the 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 torque 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 the running of the vehicle 500 is controlled.

Further, when the engine required torque TE is "0" and the condition capable of stopping the operation of the internal combustion engine 10 is satisfied, the control device 100 assumes that there is a request to stop the operation of the internal combustion engine 10. The control device 100 automatically stops the operation of the internal combustion engine 10 by stopping fuel injection and ignition. Then, when the start condition of the internal combustion engine 10 which is stopped is satisfied when the engine required torque TE exceeds "0", the control device 100 assumes that there is a start request of the internal combustion engine 10. The internal combustion engine 10 that has been stopped is automatically started by starting cranking, fuel injection, and ignition by the first MG71. In this way, the control device 100 executes the intermittent operation of the internal combustion engine 10 by executing the automatic stop and the automatic start of the internal combustion engine 10. Further, the control device 100 stops the operation of the internal combustion engine 10 when the vehicle driver requests to stop the operation of the internal combustion engine 10. Further, the control device 100 starts the internal combustion engine 10 when the vehicle driver requests to start the internal combustion engine 10.

Next, various processes executed by the control device 100 in order to execute the start-up amount increase will be described with reference to FIGS. 2 to 9.
FIG. 2 shows a processing procedure for the valve temperature estimation process for calculating the valve temperature THV, which is the estimated temperature of the intake valve 15 when the operation of the internal combustion engine 10 is stopped, for each cylinder. The valve temperature estimation process is repeatedly executed by the control device 100 while the internal combustion engine 10 is stopped. Further, in the following, the step number is represented by a number with "S" added at the beginning.

When this process is started, the control device 100 acquires the current operation stop time TS, the current cooling water temperature THW, and the stop crank angle CRAS (S100). The operation stop time TS is measured when the operation of the internal combustion engine 10 is automatically stopped, or when the operation of the internal combustion engine 10 is stopped in response to a request from the vehicle driver to stop the operation of the internal combustion engine 10. Then, when the internal combustion engine 10 that has been stopped is started, the operation stop time TS is reset to "0". The crank angle when stopped CRAS is the crank angle when the internal combustion engine 10 is in the current stop state, that is, the crank when the operation of the internal combustion engine 10 is stopped and the rotation of the crankshaft 34 is stopped due to the operation stop request. It is a horn. When the operation of the internal combustion engine 10 is stopped, the control device 100 stores the stopped crank angle CRAS in the memory 120.

Next, the control device 100 calculates the valve temperature THV for each cylinder based on the acquired operation stop time TS, cooling water temperature THW, and stop crank angle CRAS (S110). This valve temperature THV is calculated as follows.

As shown in FIG. 3, the valve temperature THV is calculated to be a lower value as the operation stop time TS becomes longer. This is because the longer the operation stop time TS, the lower the temperature of the intake valve 15. Further, the lower the cooling water temperature THW, the lower the valve temperature THV is calculated. This is because the lower the cooling water temperature THW during the shutdown, the lower the temperature of the intake valve 15.

Further, the control device 100 discriminates between the cylinder in which the intake valve 15 is in the valve open state and the cylinder in which the intake valve 15 is in the closed state based on the crank angle CRAS when stopped. Then, the valve temperature THV of the cylinder in which the intake valve 15 is in the closed state is calculated so as to be lower than the valve temperature THV of the cylinder in which the intake valve 15 is in the valve open state. This is due to the following reasons.

That is, since the opening / closing operation of the intake valve 15 is stopped during the operation stop before the engine is started, in the internal combustion engine 10 having a plurality of cylinders, the intake valve 15 is stopped in the open state during the operation stop. There are cylinders that are closed and cylinders that are stopped while the valve is closed. Here, the intake valve 15 that is in the closed state during the operation stop is in the valve open state during the operation stop because its umbrella portion is seated in the opening of the intake port 12 provided in the cylinder head 10H. The temperature is more likely to drop than that of the intake valve 15. Therefore, the temperature of the intake valve 15 that is in the closed state during the operation stop is lower than the temperature of the intake valve 15 that is in the valve open state during the operation stop.

When the valve temperature THV is calculated for each cylinder in this way, the control device 100 temporarily ends this process. By repeatedly executing such a valve temperature estimation process while the internal combustion engine 10 is stopped, the valve temperature THV during the shutdown is updated.

FIG. 4 shows a processing procedure for the port temperature estimation process for calculating the port temperature THP, which is the estimated temperature of the wall surface of the intake port 12 when the operation of the internal combustion engine 10 is stopped. The port temperature estimation process is also repeatedly executed by the control device 100 while the internal combustion engine 10 is stopped. Since the temperature of the intake port 12 when the internal combustion engine 10 is stopped is substantially the same for each cylinder, the port temperature THP calculated by this process is used as a value indicating the temperature of the intake port 12 of each cylinder. To.

When this process is started, the control device 100 acquires the current operation stop time TS and the current cooling water temperature THW (S150).
Next, the control device 100 calculates the port temperature THP based on the acquired operation stop time TS and the cooling water temperature THW (S160). This port temperature THP is calculated as follows.

As shown in FIG. 5, the port temperature THP is calculated to be a lower value as the operation stop time TS becomes longer. This is because the longer the operation stop time TS, the lower the wall surface temperature of the intake port 12. Further, the lower the cooling water temperature THW, the lower the valve temperature THV is calculated. This is because the lower the cooling water temperature THW during the shutdown, the lower the wall surface temperature of the intake port 12.

When the port temperature THP is calculated in this way, the control device 100 temporarily ends this process. By repeatedly executing such a port temperature estimation process while the internal combustion engine 10 is stopped, the port temperature THP during the shutdown is updated.

FIG. 6 shows a processing procedure for the total amount adjustment process for adjusting the total amount ZT through the calculation of the increase value Z, the attenuation start time DECT, and the attenuation rate DECS. The control device 100 starts executing the series of processes shown in FIG. 6 when a start request is made to the internal combustion engine 10 that has been stopped.

When this process is started, the control device 100 acquires the currently calculated valve temperature THV and port temperature THP of each cylinder (S200). By executing the process of S200, the control device 100 sets the latest values of the valve temperature THV and the port temperature THP calculated during the shutdown to the valve temperature THV of each cylinder and the internal combustion engine 10 at the start of engine start. Obtained as the port temperature THP of.

Next, the control device 100 calculates the increase value Z, the damping start time DECT, and the damping speed DECT based on the valve temperature THV of each cylinder at the start of engine start and the port temperature THP of the internal combustion engine 10 (S210). ).

As shown in FIG. 7, the lower the port temperature THP at the start of engine start, the larger the increase value Z is set. Further, the increase value Z is set to a larger value as the cylinder has a lower valve temperature THV at the start of engine start. Therefore, the lower the valve temperature THV at the start of engine start and the larger the amount of fuel adhering to the intake valve 15, the larger the total amount ZT that is increased by increasing the amount at start.

As shown in FIG. 8, the lower the port temperature THP at the start of engine start, the longer the attenuation start time DECT is set. Further, the lower the valve temperature THV at the start of engine start, the longer the damping start time DECT is set. Therefore, the lower the valve temperature THV at the start of engine start and the larger the amount of fuel adhering to the intake valve 15, the larger the total amount ZT that is increased by increasing the amount at start.

As shown in FIG. 9, the lower the port temperature THP at the start of engine start, the slower the damping speed DECS is set. Further, the lower the valve temperature THV at the start of engine start, the slower the damping speed DECS is set. Therefore, the lower the valve temperature THV at the start of engine start and the larger the amount of fuel adhering to the intake valve 15, the larger the total amount ZT that is increased by increasing the amount at start.

When the increase value Z, the attenuation start time DECT, and the attenuation speed DECT are calculated in this way, the control device 100 ends this process. Then, when the engine start is started, the control device 100 performs the start-up increase using the calculated increase value Z, the attenuation start time DECT, and the attenuation speed DECT.

The operation and effect of this embodiment will be described.
(1-1) The longer the operation stop time TS or the lower the cooling water temperature THW during the operation stop, the lower the temperature of the intake valve 15 of each cylinder during the operation stop. Further, the temperature of the intake valve 15 during the stop of operation also differs depending on the state of the intake valve 15 in each cylinder during the stop of operation. That is, the temperature of the intake valve 15 which is closed while the operation is stopped is lower than that of the intake valve 15 which is opened. Therefore, in the present embodiment, the valve temperature THV, which is an estimated value of the temperature of the intake valve 15 of each cylinder while the operation is stopped, is calculated by executing the valve temperature estimation process.

Here, since the intake valve 15 whose temperature is low while the operation is stopped also has a low temperature at the start of engine start, the amount of fuel adhering to the engine start is large. Therefore, in order to stabilize the combustion of the air-fuel mixture at the time of starting the engine, it is necessary to increase the total amount ZT of the cylinder in which the temperature of the intake valve 15 is low.

Therefore, in the present embodiment, by executing the above-mentioned total amount adjustment process shown in FIG. 6, the total amount ZT of the increased fuel injection amount of the cylinder having the estimated valve temperature THV is high. It is made larger than the total amount ZT of the increase in the fuel injection amount of. More specifically, the increase value Z of the cylinder having a low valve temperature THV is set to a value larger than the increase value Z of the cylinder having a high valve temperature THV. Further, the damping start time DECT of the cylinder having a low valve temperature THV is set to be longer than the damping start time DECT of the cylinder having a high valve temperature THV. Further, the damping speed DECS of the cylinder having a low valve temperature THV is set to a speed slower than the damping speed DECS of the cylinder having a high valve temperature THV.

Therefore, the total amount ZT of the increased fuel injection amount is adjusted for each cylinder according to the amount of fuel adhering to the intake valve 15 when the engine is started, and is thereby supplied to the combustion chamber 30 of each cylinder. Since the excess or deficiency of the amount of fuel produced can be suppressed, the combustion of the air-fuel mixture becomes stable when the engine is started.

(Second Embodiment)
Next, a second embodiment of the control device for the internal combustion engine will be described with reference to FIGS. 10 to 13.

In the total amount adjustment process described in the first embodiment, the increase value Z for adjusting the total amount ZT, the attenuation start time DECT, and the attenuation rate DECT are set based on the calculated valve temperature THV and port temperature THP.

On the other hand, in the present embodiment, the increase value Z for adjusting the total amount ZT and the increase value Z for adjusting the total amount ZT based on the operation stop time TS, the cooling water temperature THW, and the stop crank angle CRAS without calculating the valve temperature THV and the port temperature THP. The damping start time DECT and the damping speed DECT are directly set, which is different from the first embodiment. Therefore, in the following, the present embodiment will be described focusing on such differences.

FIG. 10 shows a procedure of the total amount adjustment process executed by the control device 100. The control device 100 starts executing the series of processes shown in FIG. 10 when a start request is made to the internal combustion engine 10 that has been stopped.

When this process is started, the control device 100 acquires the operation stop time TS, the current cooling water temperature THW, that is, the cooling water temperature THW at the start of engine start, and the crank angle CRAS at stop (S300).

Next, the control device 100 calculates the increase value Z, the damping start time DECT, and the damping speed DECT based on the acquired operation stop time TS, cooling water temperature THW, and stop crank angle CRAS (S310).

As shown in FIG. 11, the longer the operation stop time TS, the larger the increase value Z is set. This is because the longer the operation stop time TS, the lower the temperature of the intake valve 15 and the intake port 12 when starting the engine start, and it is necessary to increase the total amount ZT. Further, the lower the cooling water temperature THW, the larger the increase value Z is set. This is because the lower the cooling water temperature THW when starting the engine start, the lower the temperature of the intake valve 15 and the intake port 12 when starting the engine start, and it is necessary to increase the total amount ZT. ..

Further, the control device 100 discriminates between the cylinder in which the intake valve 15 is in the open state and the cylinder in which the intake valve 15 is in the closed state during the operation stop, based on the crank angle CRAS at the time of stop. Then, the increase value Z of the cylinder in which the intake valve 15 is in the closed state is set to a value larger than the increase value Z in the cylinder in which the intake valve 15 is in the open state. This is due to the following reasons.

That is, as described above, the temperature of the intake valve 15 that is in the closed state during the operation stop is lower than the temperature of the intake valve 15 that is in the valve open state during the operation stop. Therefore, the temperature of the intake valve 15 at the start of engine start is higher in the intake valve 15 which was in the closed state during the operation stop than in the intake valve 15 which was in the valve open state when the operation was stopped. This is because the total amount ZT of the cylinders having a low temperature of the intake valve 15 needs to be larger than the total amount ZT of the cylinders having a high temperature of the intake valve 15.

Further, as shown in FIG. 12, the longer the operation stop time TS, the longer the decay start time DECT is set. This is also because the longer the operation stop time TS, the lower the temperature of the intake valve 15 and the intake port 12 when starting the engine start, and it is necessary to increase the total amount ZT. Further, the lower the cooling water temperature THW, the longer the decay start time DECT is set. This is also because the lower the cooling water temperature THW when starting the engine start, the lower the temperature of the intake valve 15 and the intake port 12 when starting the engine start, and it is necessary to increase the total amount ZT. ..

Further, the control device 100 discriminates between the cylinder in which the intake valve 15 is in the open state and the cylinder in which the intake valve 15 is in the closed state during the operation stop, based on the crank angle CRAS at the time of stop. Then, the damping start time DECT of the cylinder in which the intake valve 15 is in the closed state is set to a longer time than the damping start time DECT of the cylinder in which the intake valve 15 is in the valve open state. As described above, the temperature of the intake valve 15 at the start of engine start is higher than that of the intake valve 15 which was in the valve open state when the operation is stopped. This is because the valve 15 is lower, and the total amount ZT of the cylinders having a low temperature of the intake valve 15 needs to be larger than the total amount ZT of the cylinders having a high temperature of the intake valve 15.

Further, as shown in FIG. 13, the longer the operation stop time TS, the slower the damping speed DECS. This is also because the longer the operation stop time TS, the lower the temperature of the intake valve 15 and the intake port 12 when starting the engine start, and it is necessary to increase the total amount ZT. Further, the lower the cooling water temperature THW, the slower the decay rate DECS. This is also because the lower the cooling water temperature THW when starting the engine start, the lower the temperature of the intake valve 15 and the intake port 12 when starting the engine start, and it is necessary to increase the total amount ZT. ..

Further, the control device 100 discriminates between the cylinder in which the intake valve 15 is in the open state and the cylinder in which the intake valve 15 is in the closed state during the operation stop, based on the crank angle CRAS at the time of stop. Then, the damping speed DECS of the cylinder in which the intake valve 15 is in the closed state is slower than the damping speed DECS of the cylinder in which the intake valve 15 is in the valve open state. As described above, the temperature of the intake valve 15 at the start of engine start is higher than that of the intake valve 15 which was in the valve open state when the operation is stopped. This is because the valve 15 is lower, and the total amount ZT of the cylinders having a low temperature of the intake valve 15 needs to be larger than the total amount ZT of the cylinders having a high temperature of the intake valve 15.

When the increase value Z, the attenuation start time DECT, and the attenuation speed DECT are calculated in this way, the control device 100 ends this process. Then, when the engine start is started, the control device 100 performs the start-up increase using the calculated increase value Z, the attenuation start time DECT, and the attenuation speed DECT.

The operation and effect of this embodiment will be described.
(2-1) By executing the above total amount adjustment process, the total amount ZT of the increase in the fuel injection amount in the cylinder in which the intake valve 15 was closed during the operation stop is the intake valve 15 during the operation stop. Is larger than the total amount ZT of the increase in the fuel injection amount in the cylinder in which the valve was opened. Therefore, also in the present embodiment, the total amount ZT for the increase in the fuel injection amount is adjusted for each cylinder according to the amount of fuel adhering to the intake valve 15 at the time of starting the engine, whereby for each cylinder. Since the excess or deficiency of the amount of fuel supplied to the combustion chamber 30 can be suppressed, the combustion of the air-fuel mixture becomes stable when the engine is started.

(2-2) The longer the operation stop time TS and the larger the amount of fuel adhering to the intake valve 15 at the time of starting the engine, the larger the total amount ZT for the increase in the fuel injection amount. Therefore, the excess or deficiency of the amount of fuel supplied to the combustion chamber 30 of each cylinder can be further suppressed, and the combustion of the air-fuel mixture becomes more stable when the engine is started.

(2-3) When the cooling water temperature THW at the start of engine start is low and the amount of fuel adhering to the intake valve 15 at the start of engine start is large, the total amount ZT of the increased fuel injection amount is increased. Therefore, the excess or deficiency of the amount of fuel supplied to the combustion chamber 30 of each cylinder can be further suppressed, and the combustion of the air-fuel mixture becomes more stable when the engine is started.

(Third Embodiment)
Next, a third embodiment of the control device for the internal combustion engine will be described with reference to FIGS. 14 and 15.

In the valve temperature estimation process described in the first embodiment described above, by grasping the valve open state and the valve closed state of the intake valve 15 of each cylinder during operation stop based on the crank angle CRAS at the time of stop, each cylinder The valve temperature THV was calculated.

On the other hand, in the present embodiment, as the crank angle sensor 80, a sensor that makes it difficult to detect the crank angle when the engine rotation speed is close to "0", for example, an electromagnetic pickup type sensor is adopted. The crank angle CRAS when stopped cannot be detected. Therefore, it is not possible to grasp whether the state of the intake valve 15 of each cylinder during the operation stop is the valve open state or the valve closed state.

Therefore, in the present embodiment, the valve temperature estimation process different from that in the first embodiment is executed, and this point is different from the first embodiment. Therefore, in the following, the present embodiment will be described focusing on such differences.

FIG. 14 shows the valve temperature estimation process of the present embodiment. This valve temperature estimation process is also repeatedly executed by the control device 100 while the operation of the internal combustion engine 10 is stopped.
When this process is started, the control device 100 acquires the operation stop time TS and the current cooling water temperature THW (S400).

Next, the control device 100 calculates the valve temperature THV of the intake valve 15 based on the acquired operation stop time TS and the cooling water temperature THW (S410).
Here, even if the state of the intake valve 15 of each cylinder during the shutdown is unknown, the valve is opened during the shutdown by performing a conformity test based on the shutdown time TS and the cooling water temperature THW during the shutdown. It is possible to estimate the average value of the temperature of the intake valve 15 which has been set to 1 and the temperature of the intake valve 15 which has been closed while the operation is stopped. Therefore, in the present embodiment, the average value of the temperatures of the intake valves 15 of each cylinder is calculated as the valve temperature THV.

As shown in FIG. 15, the longer the operation stop time TS, the lower the valve temperature THV is calculated. This is because the longer the operation stop time TS, the lower the temperature of the intake valve 15. Further, the lower the cooling water temperature THW, the lower the valve temperature THV is calculated. This is because the lower the cooling water temperature THW during the shutdown, the lower the temperature of the intake valve 15.

When the valve temperature THV is calculated in this way, the control device 100 temporarily ends this process. By repeatedly executing such a valve temperature estimation process while the internal combustion engine 10 is stopped, the valve temperature THV during the shutdown is updated. Then, when the total amount adjusting process shown in FIG. 6 is executed at the time of starting the engine, the valve temperature THV is acquired, and the total amount ZT is adjusted based on the valve temperature THV and the port temperature THP.

The operation and effect of this embodiment will be described.
(3-1) Based on the operation stop time TS and the cooling water temperature THW, the temperature of the intake valve 15 that was in the valve open state during the operation stop and the intake valve 15 that was in the valve closed state during the operation stop. The valve temperature THV, which is the average value of the temperatures of the above, is calculated. Then, as the valve temperature THV is lower, a process of increasing the total amount ZT by the increase in the fuel injection amount is executed. Therefore, according to the present embodiment, the total amount ZT of the increased fuel injection amount cannot be adjusted for each cylinder, but even when the state of the intake valve 15 of each cylinder during the shutdown is unknown. At least the total amount ZT will be adjusted according to the amount of fuel adhering to the intake valve 15 when the engine is started. As a result, the excess or deficiency of the amount of fuel supplied to the combustion chamber 30 can be suppressed, so that the combustion of the air-fuel mixture becomes stable when the engine is started.

(Fourth Embodiment)
Next, a fourth embodiment of the control device for the internal combustion engine will be described with reference to FIGS. 16 and 17.

The atmosphere of the catalyst 23 is in a rich state during the execution of the above-mentioned increase in the amount at the time of starting, and if the operation of the internal combustion engine 10 is stopped in this rich state, the exhaust gas purification capacity of the catalyst 23 at the next engine starting May decrease temporarily. Therefore, in the present embodiment, when a request to stop the operation of the internal combustion engine 10 occurs during the execution of the increase in the amount at the time of starting, the stop delay process for delaying the operation stop of the internal combustion engine 10 until the atmosphere of the catalyst 23 becomes stoichiometric. We are trying to prevent such a decrease in exhaust purification capacity.

Here, in the hybrid vehicle 500 equipped with an internal combustion engine and an electric motor as prime movers, fuel efficiency is improved by stopping the operation of the internal combustion engine 10, but the stop delay process is executed to stop the operation of the internal combustion engine 10. If is delayed, the fuel efficiency will deteriorate accordingly. Therefore, in the present embodiment, the control device 100 suppresses such deterioration of fuel consumption by executing the process shown in FIG.

FIG. 16 shows a procedure for a process in which the control device 100 starts execution when an operation stop request for the internal combustion engine 10 occurs during execution of the start-up increase.
When this process is started, the control device 100 determines whether or not the current vehicle speed SP is equal to or less than the threshold value SPref (S500). As the threshold value SPref, a vehicle speed low enough to allow the vehicle 500 to travel only with the torque of the second MG 72 is set in advance.

Then, when it is determined that the vehicle speed SP exceeds the threshold value SPref (S500: NO), the control device 100 determines whether or not the increase value Z is currently being attenuated (S510). Then, when it is determined that the increase value Z is being attenuated (S510: YES), the control device 100 executes the process of S530. On the other hand, when it is determined that the increase value Z is not being attenuated (S510: NO), that is, when the increase value Z has not yet been started to be attenuated, the control device 100 forcibly causes the increase value Z to be attenuated. Start (S520). Then, the process of S530 is executed. By the way, when the attenuation of the increase value Z is completed and the increase at the start is completed, the atmosphere of the catalyst 23 becomes stoichiometric after that, but in order to bring the atmosphere of the catalyst 23 into the stoichiometric state earlier, the increase at the start is required. After completion, it is desirable to temporarily set the air-fuel ratio of the air-fuel mixture to a leaner air-fuel ratio than the theoretical air-fuel ratio.

In S530, the control device 100 determines whether or not the atmosphere of the catalyst 23 can be determined based on the detected value of the rear sensor 89. In this S530, when the oxygen concentration cannot be detected by the rear sensor 89, such as when the rear sensor 89 is inactive or when the rear sensor 89 is determined to have an abnormality, the control device 100 Determines that it is impossible to determine the atmosphere of the catalyst 23 based on the value detected by the rear sensor 89. On the other hand, when the rear sensor 89 is in an activated state without any abnormality and the oxygen concentration can be detected by the rear sensor 89, the control device 100 is in a state where the atmosphere of the catalyst 23 can be determined by the detected value of the rear sensor 89. Judge that there is.

Then, when it is determined in S530 that the atmosphere of the catalyst 23 can be determined by the detection value of the rear sensor 89 (S530: YES), the control device 100 determines the atmosphere of the catalyst 23 based on the detection value of the rear sensor 89. Determines whether or not is in a stoichiometric state (S540). The control device 100 repeatedly executes the process of S540 until it is determined that the atmosphere of the catalyst 23 is in a stoichiometric state.

Then, when it is determined that the atmosphere of the catalyst 23 is in a stoichiometric state (S540: YES), the control device 100 executes the operation stop of the internal combustion engine 10 by stopping the fuel injection and the ignition (S570). When the stop delay process for delaying the operation stop of the internal combustion engine 10 is executed until the atmosphere of the catalyst 23 becomes stoichiometric even if the operation stop request is generated in this way, the control device 100 ends this process.

When it is determined in the above S530 that the atmosphere of the catalyst 23 cannot be determined by the detection value of the rear sensor 89 (S530: NO), the control device 100 determines the air based on the cooling water temperature THW at the start of engine start. The quantity threshold GASref is calculated (S550). The air amount threshold value GASref is an integrated air amount obtained by integrating the amount of air sucked into the internal combustion engine 10 from the end of the increase in the amount at the start to the time when the atmosphere of the catalyst 23 becomes stoichiometric.

Here, the larger the total amount ZT of the increase in the fuel injection amount due to the increase at the start time, the larger the integrated air amount GAS required for the atmosphere of the catalyst 23 to become stoichiometric. Further, as described above, the total amount ZT is increased as the valve temperature THV and the port temperature THP at the start of the engine start are lower, but the valve temperature THV and the port temperature THP at the start of the engine start are the engine. The lower the cooling water temperature THW at the start of the start, that is, the lower the cooling water temperature THW finally acquired during the shutdown, the lower the temperature. Therefore, the total amount ZT increases as the cooling water temperature THW at the start of engine start is lower.

Therefore, as shown in FIG. 17, the control device 100 increases the value of the air amount threshold value GASref as the cooling water temperature THW at the start of engine start is low and the total amount ZT is large. The value of GASref is variably set based on the cooling water temperature THW at the start of engine start. The air amount threshold value GASref may be set based on the total amount ZT, the increase value Z, the attenuation start time DECT, and the attenuation rate DECS.

When the air amount threshold value GASref is calculated in this way, the control device 100 determines whether or not the current integrated air amount GAS is equal to or greater than the air amount threshold value GASref (S560). The integrated air amount GAS is a time-integrated value of the intake air amount GA detected after the start-up increase is completed, and is measured by the control device 100. The control device 100 repeatedly executes the process of S560 until it is determined that the integrated air amount GAS is equal to or greater than the air amount threshold value GASref.

Then, when it is determined that the integrated air amount GAS is equal to or greater than the air amount threshold value GASref (S560: YES), the control device 100 executes the process of S570 to stop the operation of the internal combustion engine 10. Even if the operation stop request is generated in this way, the stop delay process for delaying the operation stop of the internal combustion engine 10 is executed until it is determined that the atmosphere of the catalyst 23 is in a stoichiometric state based on the integrated air amount GAS. The device 100 ends this process.

On the other hand, when it is determined in S500 that the vehicle speed SP is equal to or less than the threshold value SPref (S500: YES), the control device 100 executes the process of S570 without executing the stop delay process described above. , The operation of the internal combustion engine 10 is stopped, and this process is completed.

Next, the operation and effect of this embodiment will be described.
(4-1) If the vehicle speed SP when the operation stop request is generated during the execution of the start-up increase due to the negative determination in S500 of FIG. 16 is equal to or less than the specified threshold value SPref, S570 of FIG. By executing the above-mentioned process, the operation of the internal combustion engine 10 is stopped without executing the above-mentioned stop delay process. Therefore, in a situation where the vehicle speed SP is equal to or less than the threshold value SPre, it is possible to suppress deterioration of fuel efficiency due to the execution of the stop delay process.

(4-2) Based on the detection value of the rear sensor 89 that detects the oxygen concentration of the exhaust gas that has passed through the catalyst 23, it can be determined whether or not the atmosphere of the catalyst 23 is in a stoichiometric state. However, if it is not possible to determine whether or not the atmosphere of the catalyst 23 is in a stoichiometric state based on the detected value of the rear sensor 89, the stop delay process cannot be executed. Therefore, in the present embodiment, when it is determined that the atmosphere of the catalyst 23 cannot be determined by the detection value of the rear sensor 89 by the negative determination in S530 of FIG. 16, the integrated air amount GAS is determined. When the air amount threshold value is equal to or higher than the GASref and it can be estimated that the atmosphere of the catalyst 23 is in a stoichiometric state, the operation of the internal combustion engine 10 is stopped. Therefore, even when it is impossible to determine the atmosphere of the catalyst 23 based on the detected value of the rear sensor 89, the stop delay process can be executed.

(4-3) The larger the total amount ZT of the increase in the fuel injection amount due to the increase at the start time, the larger the integrated air amount GAS required for the atmosphere of the catalyst 23 to become stoichiometric. In this respect, in the present embodiment, the cooling water temperature THW at the start of engine start is low, and the air amount threshold value GASref is variably set to a larger value as the total amount ZT increases. Therefore, even if the total amount ZT is different. , It is possible to appropriately determine whether or not the atmosphere of the catalyst 23 is in a stoichiometric state.

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 order to adjust the total amount ZT, the increase value Z, the attenuation start time DECT, and the attenuation speed DECT are variably set. In addition, one of the increase value Z, the attenuation start time DECT, and the attenuation speed DECT may be variably set, while the remaining two may be fixed values. Further, any two of the increase value Z, the attenuation start time DECT and the attenuation speed DECT may be variably set, while the remaining one may be a fixed value.

-In the second embodiment, the total amount ZT is adjusted based on the state of the intake valve 15, the operation stop time TS, and the cooling water temperature THW, but the adjustment of the total amount ZT based on the operation stop time TS may be omitted. Even in this case, an action effect other than the above (2-2) can be obtained. Further, the adjustment of the total amount ZT based on the cooling water temperature THW may be omitted, and even in this case, an action effect other than the above (2-3) can be obtained. Further, the adjustment of the total amount ZT based on the operation stop time TS and the cooling water temperature THW may be omitted, and even in this case, the effects other than the above (2-2) and the above (2-3) can be obtained.

Incidentally, as described above, the longer the operation stop time TS or the lower the cooling water temperature THW at the time of starting the engine, the lower the temperature of the intake valve 15 and the larger the amount of fuel adhering at the time of starting the engine. Therefore, more simply, the total amount ZT is adjusted so that the longer the operation stop time TS is, the larger the total amount ZT is, or the total amount ZT is adjusted so that the lower the cooling water temperature THW is, the larger the total amount ZT is. You may do it.

-The air amount threshold value GASref described in the fourth embodiment may be set to a fixed value. Even in this case, even in this case, an action effect other than the above (4-3) can be obtained.
-The processing of S530, S550, and S560 described in the fourth embodiment is omitted. Then, the process of S540 may be executed after the process of S520 or after a positive determination is made in S510. Even in this case, the action and effect described in (4-1) above can be obtained.

-The total amount ZT may be adjusted according to the amount of fuel adhering to the intake port 12 in another manner.
-The vehicle to which each of the above embodiments and the modified examples is applied is not limited to a hybrid vehicle, and may be a vehicle provided only with an internal combustion engine as a vehicle prime mover.

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.

<Other changes>
In the internal combustion engine described in Japanese Patent Application Laid-Open No. 2005-422682, the throttle valve is opened and closed after a predetermined time has elapsed from the start of idling to suppress freezing of the throttle valve during engine operation.

By the way, the throttle valve 14 may freeze even while the operation of the internal combustion engine 10 is stopped, and if the engine start is started while the internal combustion engine 10 is stopped, the following inconveniences may occur.
As shown in FIG. 18, while the operation of the internal combustion engine 10 is stopped, the opening opening TAa at the time of stopping is maintained. The stop opening TAa is the opening of the throttle valve 14 when the power supply to the electric motor that drives the throttle valve 14 is stopped, and is, for example, an opening that allows shunting. When the power supply to the electric motor is stopped, the opening degree of the throttle valve 14 is maintained at the stopped opening degree TAa by utilizing the force of an urging member such as a spring provided on the throttle valve 14. By the way, in the present embodiment, the opening degree of the throttle valve 14 in the fully closed state is set to "0", and as the value of the opening degree increases, the throttle valve 14 approaches the fully opened state and is sucked into the internal combustion engine 10. The amount of air increases.

On the other hand, when the engine is started, the opening degree of the throttle valve 14 is controlled so that the specified starting opening opening TAsp suitable for starting is obtained. The control device 100 calculates various values of the opening opening TAsp at the time of starting according to the state of the internal combustion engine 10 at the time of starting the engine and the output request by the vehicle driver.

Here, as shown in FIG. 18, when the opening opening TAsp at the start is an opening in the direction in which the intake air amount is smaller than the opening TAa at the stop, that is, the opening TAsp at the start is from the opening TAa at the stop. When the opening degree of the throttle valve 14 is changed from the opening opening TAa at the time of opening to the opening degree TAsp at the time of starting, the throttle valve 14 is frozen and the outer peripheral edge 14g of the throttle valve 14 is frozen. If ice BL adheres between the throttle valve 11 and the intake passage 11, the ice BL is caught between the outer peripheral edge 14g and the intake passage 11, and the opening degree of the throttle valve 14 is set to the specified opening degree. There is a risk of losing control.

In view of these problems, it is advisable to execute the target opening degree setting process shown in FIG.
The control device 100 starts executing the target opening degree setting process shown in FIG. 19 when an engine start request is generated.

When this process is started, the control device 100 acquires the current outside air temperature THout, the current cooling water temperature THW, and the operation stop time TS (S600).
Next, the control device 100 determines whether or not the throttle valve 14 is frozen based on the outside air temperature THout, the cooling water temperature THW, and the operation stop time TS (S610). The lower the outside air temperature THout, the lower the cooling water temperature THW, or the longer the operation stop time TS, the higher the possibility that the throttle valve 14 is frozen. Therefore, the control device 100 has the conditions that the outside temperature THout is below the specified threshold value, the cooling water temperature THW is below the specified threshold value, and the operation stop time TS is above the specified threshold value. When all of them are satisfied, it is determined that the throttle valve 14 is frozen. It should be noted that it may be determined by another method whether or not the throttle valve is frozen.

Then, when it is determined that the throttle valve 14 is not frozen (S610: NO), the control device 100 sets the starting opening TAsp calculated for the engine start this time as the target opening TAp of the throttle valve 14. (S640), this process is terminated.

On the other hand, when it is determined that the throttle valve 14 is frozen (S610: YES), the control device 100 has an opening degree TAsp calculated for the engine start this time, which is smaller than the stop opening degree TAa. It is determined whether or not there is, that is, whether or not the opening degree TAsp at the start is the opening degree in the direction in which the intake air amount decreases from the opening degree TAa at the time of stopping (S620).

Then, when it is determined that the opening opening TAsp at the start is larger than the opening TAa at the stop (S620: NO), the control device 100 executes the process of S640 and ends this process. To do.

On the other hand, when it is determined that the opening opening TAsp at the start is smaller than the opening TAa at the stop (S620: YES), the control device 100 adds the specified value B to the opening TAa at the stop. Is set to the target opening degree TAp of the throttle valve 14 (S630). When the process of S630 is executed, as shown in FIG. 18, the opening degree of the throttle valve 14 is controlled to the opening degree obtained by adding the specified value B to the stopped opening degree TAa. The opening is changed in the direction of increasing the intake air amount, that is, on the opening side.

When the opening degree of the throttle valve 14 is changed to the opening side in this way, the control device 100 then sets the starting opening degree TAsp calculated for the engine start this time to the target opening degree TAp of the throttle valve 14 (S640). ), End this process.

By executing such a series of processes, it is determined in S610 that the throttle valve 14 is frozen, and in S620, the intake air amount is reduced in the starting opening TAsp as compared with the stopping opening TAa. When it is determined that the opening degree is in the direction of opening, the opening degree of the throttle valve 14 is changed in the direction in which the intake air amount increases from the stopped opening degree TAa, that is, on the opening side by the processing of S630. The ice BL is crushed by. After that, the opening degree of the throttle valve 14 is adjusted to the starting opening degree TAsp by the processing of S640. Since the ice BL is crushed prior to changing the opening to the opening TAsp at the time of starting in this way, the ice BL is suppressed from being caught between the outer peripheral edge 14g and the intake passage 11, whereby the throttle valve 14 is suppressed. Even when there is a possibility that the throttle valve 14 is frozen, the opening degree of the throttle valve 14 can be controlled to a predetermined opening degree.

The internal combustion engine described in Japanese Patent Application Laid-Open No. 2002-161766 is provided with a hydraulic variable valve mechanism for changing the valve timing of engine valves such as an intake valve and an exhaust valve, similarly to the internal combustion engine 10. The variable valve mechanism is driven by the hydraulic oil sent from the oil pump.

Here, since a certain amount of oil pressure is required to drive the variable valve mechanism 17, as described above, in the control device 100, the hydraulic pressure PR of the hydraulic oil sent from the oil pump 90 is a predetermined threshold value. When the value is PRref or higher, the variable valve mechanism 17 is driven.

By the way, when the operation of the internal combustion engine 10 is stopped and the drive of the oil pump 90 is stopped, the hydraulic oil is discharged from the variable valve mechanism 17. Therefore, the hydraulic PR of the hydraulic oil sent from the oil pump 90 should be set to the above threshold PRref or higher until the driving of the oil pump 90 is started at the time of engine start and the variable valve mechanism 17 is filled with the hydraulic oil. This is not possible, and a delay time occurs between the start of engine start and the time when the variable valve mechanism 17 can be driven. Even when the internal combustion engine 10 includes a hydraulic variable valve mechanism for changing the valve timing of the exhaust valve 25, the same delay time occurs.

In view of these problems, it is advisable to execute the speed-up process shown in FIG.
The control device 100 starts executing the speed-increasing process shown in FIG. 20 when the engine start is started.
When this process is started, the control device 100 starts a speed-up process for increasing the rotation speed of the oil pump 90 (S700). Since the oil pump 90 included in the internal combustion engine 10 is a type of pump that is rotationally driven by the crankshaft 34, the rotational speed of the oil pump 90 depends on the rotational speed of the crankshaft 34. Therefore, in S700, the control device 100 sets the target rotation speed NEp of the engine rotation speed by adding the specified increase value ZA to the start target speed NEsp, which is the target value of the engine rotation speed set at the time of engine start. The above speed-up process is executed by setting and controlling the rotation speed of the crankshaft 34 so as to reach the target rotation speed NEp.

Next, the control device 100 determines whether or not the hydraulic PR is equal to or higher than the threshold value PRref (S710). The control device 100 repeatedly executes the process of S710 until it is determined that the hydraulic PR is equal to or higher than the threshold value PRref.

Then, when it is determined that the oil pressure PR is equal to or higher than the threshold value PRref (S710: YES), the control device 100 ends the speed increasing process of the oil pump 90 (S720). In this S720, the control device 100 sets the starting target speed NEsp to the target rotation speed NEp, so that the engine rotation speed is a value obtained by adding the increased value ZA to the starting target speed NEsp. The rotation speed of the oil pump 90 is reduced by reducing the starting speed to the target speed NEsp. Then, the control device 100 ends this process.

By executing such a series of processes, the rotation speed of the oil pump 90 is increased from the start of the engine start until the hydraulic PR of the hydraulic oil reaches the above threshold PRref, so that the oil pump per unit time. The amount of hydraulic oil sent from 90 will increase. Therefore, as compared with the case where the speed-up process is not executed, the time from the start of the engine start until the hydraulic PR of the hydraulic oil reaches the threshold value PRref is shortened, thereby shortening the delay time. Can be done.

-In the above-mentioned modification example, the speed-up process is executed until the hydraulic PR becomes equal to or higher than the threshold value PRref, but the hydraulic PR cannot be detected in the case of an internal combustion engine not provided with the pressure sensor 87. Therefore, the above speed-up process cannot be executed.

Here, as the number of rotations of the oil pump 90 after starting the engine start increases, the total amount of hydraulic oil sent from the oil pump 90 to the variable valve mechanism 17 increases. Therefore, it is determined whether or not the pressure of the hydraulic oil reaches the threshold value PRref by filling the variable valve mechanism 17 with the hydraulic oil after the engine start is started by the oil pump 90 after the engine start is started. It can be determined based on the total number of rotations.

Therefore, when the internal combustion engine 10 does not include the pressure sensor 87, the speed-up process shown in FIG. 21 may be executed instead of the speed-up process shown in FIG.
The control device 100 also starts executing the speed-increasing process shown in FIG. 21 when the engine start is started.

When this process is started, the control device 100 calculates the integrated threshold value NESref based on the current cooling water temperature THW, that is, the cooling water temperature THW at the time of starting the engine and the operation stop time TS (S800). The integrated threshold value NESref is for determining that the variable valve mechanism 17 is filled with hydraulic oil and the pressure of the hydraulic oil has reached the threshold value PRref when the integrated rotation speed NES is equal to or higher than the integrated threshold value NESref. Is the value of. The integrated rotation speed NES is the integrated rotation speed of the crankshaft 34 after the engine is started, and the control device 100 starts the measurement when the engine start is started. Since the oil pump 90 is rotationally driven by the crankshaft 34, the cumulative rotation speed NES correlates with the cumulative rotation speed of the oil pump 90 after the engine is started.

Here, the cumulative number of rotations of the oil pump 90, which can be determined that the pressure of the hydraulic oil has reached the threshold value PRref, is the amount of hydraulic oil released from the variable valve mechanism 17 during the operation stop before starting the engine. The more there are, the more. The amount of hydraulic oil released from the variable valve mechanism 17 increases as the operation stop time TS becomes longer. Further, the amount of hydraulic oil released from the variable valve mechanism 17 increases as the cooling water temperature THW at engine start is low and the viscosity of the hydraulic oil during stop operation is high. Therefore, the control device 100 variably sets the integrated threshold value NESref so that the lower the cooling water temperature THW or the longer the operation stop time TS, the larger the integrated threshold value NESref.

Next, the control device 100 starts a speed increasing process for increasing the rotation speed of the oil pump 90 (S810). The process of S810 is the same as the process of S700.
Next, the control device 100 determines whether or not the current integrated rotation speed NES is equal to or greater than the integrated threshold value NESref (S820). The control device 100 repeatedly executes the process of S820 until it is determined that the integrated rotation speed NES is equal to or greater than the integrated threshold value NESref.

Then, when it is determined that the integrated rotation speed NES is equal to or greater than the integrated threshold value NESref (S820: YES), the control device 100 ends the speed-up process of the oil pump 90 (S830). The process of S830 is the same as the process of S720. Then, the control device 100 ends this process.

By executing such a series of processes, the speed-up process is executed until the integrated rotation speed NES becomes equal to or higher than the integrated threshold value NESref. Here, the integrated threshold value NERef is set based on the operation stop time TS and the cooling water temperature THW. Therefore, the integrated threshold value NESref is set according to the amount of hydraulic oil released from the variable valve mechanism 17 during the operation stop before starting the engine, so that the variable valve mechanism 17 is completely filled with the hydraulic oil. Therefore, it becomes possible to appropriately determine that the pressure of the hydraulic oil has reached the threshold value PRref based on the integrated rotation speed NES.

When the oil pump 90 is an electric pump, the operation of the oil pump 90 is started when the engine is started. Then, the integrated rotation speed NES is defined as the integrated rotation speed of the oil pump 90 after the engine is started. Further, the integrated threshold value NESref is a threshold value corresponding to the integrated rotation speed of the oil pump 90. Then, by replacing the target rotation speed NEp and the start target speed NEsp with the target rotation speed of the oil pump 90 and the target speed set at the start, respectively, the speed-up process can be executed.

-In the above-mentioned modification example, the speed-up process is executed until the hydraulic PR becomes equal to or higher than the threshold value PRref, but the hydraulic PR cannot be detected in the case of an internal combustion engine not provided with the pressure sensor 87. Therefore, the above speed-up process cannot be executed.

Here, as the elapsed time after starting the engine becomes longer, the total amount of hydraulic oil sent from the oil pump 90 to the variable valve mechanism 17 increases. Therefore, it is determined whether or not the pressure of the hydraulic oil reaches the threshold value PRref by filling the variable valve mechanism 17 with the hydraulic oil after the engine is started, based on the elapsed time after the engine is started. Can be done.

Therefore, when the internal combustion engine 10 does not include the pressure sensor 87, the speed-up process shown in FIG. 22 may be executed instead of the speed-up process shown in FIG.
The control device 100 also starts executing the speed-increasing process shown in FIG. 22 when the engine start is started.

When this process is started, the control device 100 calculates the time threshold value Tref based on the current cooling water temperature THW, that is, the cooling water temperature THW at the time of starting the engine and the operation stop time TS (S900). The time threshold Tref is for determining that the variable valve mechanism 17 is filled with hydraulic oil and the pressure of the hydraulic oil has reached the threshold value PRref when the time ST after the start is equal to or greater than the time threshold Tref. Is the value of. The post-start time ST is the elapsed time after the engine starts, and when the engine start starts, the control device 100 starts the measurement.

Here, the elapsed time at which it can be determined that the pressure of the hydraulic oil has reached the threshold value PRref increases as the amount of hydraulic oil released from the variable valve mechanism 17 during the operation stop before starting the engine increases. Become. The amount of hydraulic oil released from the variable valve mechanism 17 increases as the operation stop time TS becomes longer. Further, the amount of hydraulic oil released from the variable valve mechanism 17 increases as the cooling water temperature THW at engine start is low and the viscosity of the hydraulic oil during stop operation is high. Therefore, the control device 100 variably sets the time threshold value Tref so that the lower the cooling water temperature THW or the longer the operation stop time TS, the longer the time threshold value Trf becomes.

Next, the control device 100 starts a speed increasing process for increasing the rotation speed of the oil pump 90 (S910). The process of S910 is the same as the process of S700.
Next, the control device 100 determines whether or not the current post-start time ST is equal to or greater than the time threshold value Tref (S920). The control device 100 repeatedly executes the process of S920 until it is determined that the time ST after the start is equal to or greater than the time threshold value Tref.

Then, when it is determined that the post-start time ST is equal to or greater than the time threshold value Tref (S920: YES), the control device 100 ends the speed-up process of the oil pump 90 (S930). The process of S930 is the same as the process of S720. Then, the control device 100 ends this process.

By executing such a series of processes, the speed-up process is executed until the post-start time ST becomes equal to or higher than the time threshold value Tref. Here, the time threshold value Tref is set based on the operation stop time TS and the cooling water temperature THW. Therefore, the time threshold value Tref is set according to the amount of hydraulic oil that has escaped from the variable valve mechanism 17 during the operation stop before starting the engine, so that the variable valve mechanism 17 is completely filled with the hydraulic oil. Therefore, it becomes possible to appropriately determine that the pressure of the hydraulic oil has reached the threshold value PRref based on the post-start time ST.

Even in this modified example, when the oil pump 90 is an electric pump, the driving of the oil pump 90 is started at the same time as the engine is started. Then, by replacing the target rotation speed NEp and the start target speed NEsp with the target rotation speed of the oil pump 90 and the target speed set at the start, respectively, the speed-up process can be executed.

The technical idea and its effect that can be grasped from the above-described embodiment and modification are described.
-Applied to internal combustion engines equipped with intake valves that open and close the intake ports provided in each of a plurality of cylinders and fuel injection valves that inject fuel into the intake ports, the fuel injection amount is increased by a specified amount when the engine is started. A control device that executes an increase in the amount at the time of starting to increase the amount by a value, and the operation is based on the operation stop time of the internal combustion engine before the engine is started and the cooling water temperature of the internal combustion engine during the operation stop before the engine is started. The average value of the temperature of the intake valve that was in the open state during the stop and the temperature of the intake valve that was in the closed state during the operation stop is estimated, and the lower the estimated average value, the more at the time of the start. A control device for an internal combustion engine that executes a process of increasing the total amount of the fuel injection amount increase during execution of the amount increase.

Even if the state of the intake valve of each cylinder during shutdown is unknown, the valve is opened during shutdown by performing a conformity test based on the shutdown time of the internal combustion engine and the cooling water temperature of the internal combustion engine during shutdown. It is possible to estimate the average value of the temperature of the intake valve that was set to 1 and the temperature of the intake valve that was closed while the operation was stopped. Therefore, in the same configuration, the temperature of the intake valve that was in the valve open state during the operation stop and the temperature of the intake valve that was in the valve closed state during the operation stop are based on the operation stop time and the cooling water temperature. I try to estimate the average value. Then, the lower the estimated average value, the larger the total amount of the increased fuel injection amount is executed. Therefore, according to the same configuration, the total amount of the increased fuel injection amount cannot be adjusted for each cylinder, but at least it is adjusted according to the amount of fuel adhering to the intake valve when the engine is started. As a result, the excess or deficiency of the amount of fuel supplied to the combustion chamber can be suppressed, so that the combustion of the air-fuel mixture becomes stable when the engine is started.

-A control device that controls the opening of the throttle valve provided in the intake passage so that the specified opening is maintained when the internal combustion engine is stopped, while the specified opening is achieved when the engine is started. When the engine start is started, a determination process for determining whether or not the throttle valve is frozen and a determination process for determining that the throttle valve is frozen and the opening degree at the time of starting the engine are started. Is the opening in the direction in which the intake air amount decreases from the stop opening, after the throttle valve opening is once changed in the direction in which the intake air amount increases from the stop opening. , A control device for an internal combustion engine that executes a process of adjusting the opening degree of the throttle valve to the opening degree at the time of starting.

The throttle valve of the internal combustion engine is maintained at a specified stop opening while the internal combustion engine is stopped, while the opening is controlled so as to have a specified start opening suitable for starting the engine. .. Here, when the opening at the start is an opening in a direction in which the intake air amount is smaller than the opening at the stop, that is, when the opening at the start is an opening on the closing side of the opening at the stop. When changing the opening of the throttle valve from the opening at stop to the opening at start, if the throttle valve is frozen and ice adheres between the outer peripheral edge of the throttle valve and the intake passage, the ice May get caught between the outer peripheral edge and the intake passage, and the opening degree of the throttle valve may not be controlled to a specified opening degree.

In this respect, in the same configuration, when it is determined that the throttle valve is frozen and the opening degree at the time of starting is an opening degree in which the intake air amount is smaller than the opening degree at the time of stopping, the opening time is stopped. The ice is crushed by once changing the opening degree of the throttle valve in the direction in which the intake air amount increases more than the opening degree, that is, on the opening side. After that, the opening degree of the throttle valve is adjusted to the opening degree at the time of starting. Since the ice is crushed prior to the change of the opening to the opening at the time of starting in this way, the biting of ice between the outer peripheral edge and the intake passage is suppressed, which may cause the throttle valve to freeze. Even if there is a property, the opening degree of the throttle valve can be controlled to a specified opening degree. Whether or not the throttle valve is frozen can be determined based on the outside air temperature, the water temperature, the operation stop time before starting the engine, and the like.

-A control device for an internal combustion engine including a hydraulic variable valve mechanism for changing the valve timing of an engine valve and an oil pump for supplying hydraulic oil to the variable valve mechanism. The variable valve mechanism is , A mechanism that is driven when the pressure of the hydraulic oil sent from the oil pump is equal to or higher than a specified threshold value, and is the oil pump from the start of engine start until the pressure reaches the threshold value. A control device for an internal combustion engine that executes a speed-increasing process for increasing the rotation speed of the oil pump to be higher than the rotation speed of the oil pump after the pressure becomes equal to or higher than the threshold value.

In the same configuration, the internal combustion engine is equipped with a hydraulic variable valve mechanism that changes the valve timing of engine valves such as the intake valve and exhaust valve, and the variable valve mechanism is driven by hydraulic oil sent from the oil pump. Will be done. Since a certain amount of oil pressure is required to drive this variable valve mechanism, the variable valve mechanism is driven when the pressure of the hydraulic oil sent from the oil pump is equal to or higher than a specified threshold value.

Here, when the operation of the internal combustion engine is stopped and the drive of the oil pump is stopped, the hydraulic oil is discharged from the variable valve mechanism. Therefore, the pressure of the hydraulic oil sent from the oil pump cannot exceed the above threshold until the oil pump is started to be driven and the variable valve mechanism is filled with the hydraulic oil when the engine is started. There is a delay time between the start of starting and the time when the variable valve mechanism can be driven.

In this respect, in the same configuration, by executing the speed-increasing process, the rotation speed of the oil pump is increased from the start of the engine start until the pressure of the hydraulic oil reaches the above threshold value, so that the unit time The amount of hydraulic oil sent from the oil pump will increase. Therefore, as compared with the case where the speed-up process is not executed, the time from the start of the engine start until the pressure of the hydraulic oil reaches the threshold value is shortened, which can shorten the delay time. ..

-In the above configuration, the speed-up process is executed until the integrated rotation number of the oil pump after the start of the engine starts becomes equal to or higher than the specified integrated threshold value, and the operation stop time of the internal combustion engine before the engine starts. A control device for an internal combustion engine that executes a threshold setting process for setting the integrated threshold value based on the cooling water temperature of the internal combustion engine at the time of starting the engine.

As the number of revolutions of the oil pump increases after the engine start is started, the total amount of hydraulic oil sent from the oil pump to the variable valve mechanism increases. Therefore, whether or not the pressure of the hydraulic oil has reached the above threshold value due to the variable valve mechanism being filled with the hydraulic oil after the engine is started is determined by the cumulative number of revolutions of the oil pump since the engine is started. Can be determined based on. Here, the cumulative number of rotations at which it can be determined that the pressure of the hydraulic oil has reached the above threshold value increases as the amount of hydraulic oil released from the variable valve mechanism during the operation stop before starting the engine increases. The amount of hydraulic oil that escapes from the variable valve mechanism increases as the operation stop time of the internal combustion engine before starting the engine becomes longer. Further, the amount of hydraulic oil discharged from the variable valve mechanism increases as the cooling water temperature at engine start is low and the viscosity of the hydraulic oil during operation stop is high.

Therefore, in the same configuration, the speed-up process is executed until the integrated rotation speed becomes equal to or higher than the specified integrated threshold value. However, the integrated threshold value is set to the operation stop time before starting the engine and cooling at the time of starting the engine. It is set based on the water temperature. Therefore, since the integrated threshold value is set according to the amount of hydraulic oil that has escaped from the variable valve mechanism during the operation stop before starting the engine, the variable valve mechanism is completely filled with the hydraulic oil and operates. It becomes possible to appropriately determine that the oil pressure has reached the threshold value based on the integrated rotation speed. In the same configuration, it can be determined that the pressure of the hydraulic oil has reached the above threshold value after the engine is started without detecting the pressure of the hydraulic oil sent to the variable valve mechanism. The speed-up process can be performed even in an internal combustion engine that does not have a sensor for detecting the pressure of such hydraulic oil. Incidentally, when the oil pump is a type of pump that is rotationally driven by the crankshaft, the cumulative rotation speed of the crankshaft 34 after the start of the engine start can be used as the cumulative rotation speed of the oil pump.

-In the above configuration, the speed-up process is executed until the elapsed time after the engine starts becomes equal to or greater than the specified time threshold value, the operation stop time of the internal combustion engine before the engine starts, and the internal combustion engine at the time of engine start. A control device for an internal combustion engine that executes a threshold value setting process for setting the time threshold value based on the cooling water temperature of the internal combustion engine.

As the elapsed time after starting the engine increases, the total amount of hydraulic oil sent from the oil pump to the variable valve mechanism increases, so the variable valve mechanism must be filled with hydraulic oil after starting the engine. Therefore, it is possible to determine whether or not the pressure of the hydraulic oil has reached the above threshold value based on the elapsed time after the engine is started. Here, the elapsed time during which it can be determined that the pressure of the hydraulic oil has reached the above threshold value becomes longer as the amount of hydraulic oil released from the variable valve mechanism during the operation stop before starting the engine increases. The amount of hydraulic oil that escapes from the variable valve mechanism increases as the operation stop time of the internal combustion engine before starting the engine becomes longer. Further, the amount of hydraulic oil discharged from the variable valve mechanism increases as the cooling water temperature at engine start is low and the viscosity of the hydraulic oil during operation stop is high.

Therefore, in the same configuration, the above speed-up process is executed until the elapsed time after the engine starts exceeds the specified time threshold value. However, the time threshold value is set to the operation stop time before the engine start and the engine start time. It is set based on the cooling water temperature in. Therefore, since the time threshold value is set according to the amount of hydraulic oil that has escaped from the variable valve mechanism during the operation stop before starting the engine, the variable valve mechanism is completely filled with the hydraulic oil and operates. It becomes possible to appropriately determine that the oil pressure has reached the above threshold value based on the elapsed time after starting the engine. In the same configuration, it can be determined that the pressure of the hydraulic oil has reached the above threshold value after the engine is started without detecting the pressure of the hydraulic oil sent to the variable valve mechanism. The speed-up process can be performed even in an internal combustion engine that does not have a sensor for detecting the pressure of such hydraulic oil.

10 ... internal combustion engine, 10H ... cylinder head, 11 ... intake passage, 12 ... intake port, 13 ... surge tank, 14 ... throttle valve, 14g ... outer peripheral edge of throttle valve, 14w ... water jacket, 15 ... intake valve, 16 ... Intake camshaft, 17 ... variable valve mechanism, 21 ... exhaust passage, 22 ... exhaust port, 23 ... ternary catalyst (catalyst), 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 wheel, 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 ... outside temperature sensor, 85 ... vehicle speed sensor, 86 ... accelerator position sensor, 87 ... pressure sensor, 88 ... front sensor, 89 ... rear sensor, 90 ... oil pump, 100 ... control device, 110 ... central processing device (CPU) ), 120 ... Memory, 200 ... PCU, 500 ... Hybrid vehicle (vehicle).

Claims (10)

It is applied to an internal combustion engine having an intake valve that opens and closes an intake port provided in each of a plurality of cylinders and a fuel injection valve that injects fuel into the intake port, and increases the fuel injection amount by a specified value when the engine is started. It is a control device that executes the increase at the start time.
Regarding the total amount of the increase in the fuel injection amount during the execution of the increase at the time of starting, the intake valve adjusts the total amount of the cylinders whose intake valve was closed during the operation stop before the engine start. A control device for an internal combustion engine that executes a total amount adjustment process that increases the total amount of the cylinders that have been opened. The internal combustion engine according to claim 1, wherein the total amount adjustment process executes a process of increasing the total amount of each cylinder as the operation stop time, which is the time during which the internal combustion engine was stopped before the engine is started, is longer. Control device. The control device for an internal combustion engine according to claim 1 or 2, wherein the total amount adjusting process executes a process of increasing the total amount of each cylinder as the cooling water temperature of the internal combustion engine becomes lower at the start of engine start. Based on the operation stop time of the internal combustion engine before the engine start, the cooling water temperature of the internal combustion engine during the operation stop, and the state of the intake valve in each cylinder during the operation stop, the operation of each cylinder is stopped. While executing the valve temperature estimation process that calculates the temperature of the intake valve,
The valve temperature estimation process is performed so that the temperature of the intake valve that is in the closed state during the operation stop is lower than the temperature of the intake valve that is in the valve open state during the operation stop. Execute the process to calculate the temperature,
The total amount adjusting process executes a process of increasing the total amount of the low temperature cylinders of the intake valve during operation stop by the total amount of the high temperature cylinders of the intake valve during operation stop. Item 2. The control device for an internal combustion engine according to Item 1. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the total amount adjusting process executes a process of increasing the total amount by increasing the increase value. When the specified attenuation start time elapses after the start-up increase is started, the process of attenuating the increase value and ending the start-up increase is executed, and the process is executed.
The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the total amount adjusting process executes a process of increasing the total amount by lengthening the damping start time. After starting the start-up increase, the process of attenuating the increase value at a predetermined damping rate to end the start-up increase is executed, and the process is executed.
The control device for an internal combustion engine according to any one of claims 1 to 6, wherein the total amount adjusting process executes a process of increasing the total amount by slowing down the damping rate. The internal combustion engine is mounted on a vehicle equipped with an internal combustion engine and an electric motor as a prime mover, and a catalyst for purifying exhaust gas is provided in an exhaust passage of the internal combustion engine.
When a request to stop the operation of the internal combustion engine occurs during the execution of the increase in the amount at the time of starting, a stop delay process for delaying the operation stop of the internal combustion engine is executed until the atmosphere of the catalyst becomes stoichiometric.
When the vehicle speed of the vehicle when the operation stop request is generated is equal to or less than a specified threshold value, the process of stopping the operation of the internal combustion engine is executed without executing the stop delay process. 7. The control device for an internal combustion engine according to any one of 7. The internal combustion engine includes a sensor that detects the atmosphere of the catalyst.
The stop delay process determines whether or not the atmosphere of the catalyst is in a stoichiometric state based on the detection value of the sensor, but when it is impossible to determine the atmosphere of the catalyst based on the detection value of the sensor. , The process of stopping the operation of the internal combustion engine is executed after the integrated air amount, which is the integrated value of the air amount sucked into the internal combustion engine, becomes equal to or higher than the specified air amount threshold value after the increase at the start time is completed. The control device for an internal combustion engine according to claim 8. The control device for an internal combustion engine according to claim 9, wherein the air amount threshold value is variably set so that the larger the total amount, the larger the value.