JP2023106776A - Control device of internal combustion engine - Google Patents

Abstract

To optimize combustion at the time of engine start.SOLUTION: A control device 100 executes increase correction of fuel at the time of engine start of an internal combustion engine 10 including a catalyst in an exhaust passage. The control device 100 selects either one of high revolution start control and low revolution start control at the time of engine start. The high revolution start control is control of starting fuel injection and ignition in a state that an engine rotation speed is high compared to the low revolution start control. The control device 100 executes processing of setting a value of at least one of the initial value of increase correction of fuel and the attenuation of increase correction of fuel to a value different between the high revolution start control and the low revolution start control.SELECTED DRAWING: Figure 1

Description

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

For example, as disclosed in Japanese Patent Application Laid-Open No. 2002-200011, fuel amount increase correction is performed at the time of starting the engine.

JP 2016-94031 A

By the way, as a method of starting the engine, there are high rotation start control in which fuel injection and ignition are started in a state where the engine rotation speed is high due to cranking, and fuel injection and ignition in a state where the engine rotation speed due to cranking is lower than that in the high rotation start control. A low rpm start control that initiates ignition may be considered. The high speed start control is characterized in that, for example, the shock at the time of starting the engine is smaller than the low speed start control. In addition, the low speed start control is characterized in that, compared to the high speed start control, the time from the generation of the start request to the actual completion of the engine start is short, that is, the so-called start response is good.

Here, the amount of air in the cylinder and the amount of oxygen stored in the catalyst at the time of starting the engine are different between the high rotation start control and the low rotation start control. Therefore, if the initial value and the attenuation amount related to fuel increase correction at engine start are set to be the same for high-speed start control and low-speed start control, it may become difficult to optimize combustion at engine start.

A control device for an internal combustion engine that solves the above problems performs a fuel amount increase correction when starting an internal combustion engine having a catalyst in an exhaust passage. This control device selects either one of the high speed start control and the low speed start control when starting the engine. The high rotation start control is control for starting fuel injection and ignition in a state where the engine rotation speed is higher than that in the low rotation start control. Then, the control device executes a process of setting at least one of the initial value of the increase correction and the attenuation amount of the increase correction to different values for the high rotation start control and the low rotation start control.

According to this configuration, when the fuel amount increase correction is performed at the time of starting the engine, at least one of the initial value and the attenuation amount related to the fuel amount increase correction is set to a value corresponding to the engine starting method. Therefore, it becomes possible to optimize the combustion at the time of starting the engine.

When the initial value of the amount increase correction is made different, the amount of fuel can be increased according to the amount of air in the cylinder at the time of starting the engine. Therefore, combustion can be optimized so that a shock does not occur at the time of starting due to an excess or deficiency of engine torque at the time of starting the engine.

Further, when the attenuation amount of the fuel increase correction is made different, the fuel amount can be increased according to the amount of oxygen stored in the catalyst when the engine is started. Therefore, combustion can be optimized so that the oxygen storage amount of the catalyst becomes an appropriate amount.

1 is a schematic diagram of a vehicle provided with a control device for an internal combustion engine according to one embodiment; FIG. It is a table|surface which shows the engine starting mode which the control apparatus of the same embodiment performs. It is a flowchart which shows the procedure of the process which the control apparatus of the same embodiment performs. It is a flowchart which shows the procedure of the process which the control apparatus of the same embodiment performs.

An embodiment of a control device for an internal combustion engine will be described below with reference to FIGS. 1 to 4. FIG.
<Vehicle configuration>
As shown in FIG. 1 , a vehicle 500 is equipped with two prime movers, an internal combustion engine 10 and an electric motor 30 . The internal combustion engine 10 includes fuel injection valves 12 that supply fuel to the cylinders. The internal combustion engine 10 has an intake passage 13 . An electric throttle valve 14 is provided in the intake passage 13 to adjust the amount of intake air. The internal combustion engine 10 has an exhaust passage 16 . A catalyst 17 for purifying exhaust gas is provided in the exhaust passage 16 . In the combustion chamber of the internal combustion engine 10, an engine output is obtained by burning a mixture of the intake air and the fuel injected from the fuel injection valve 12. As shown in FIG.

An electric starter motor 85 driven by power supply from a low-voltage battery 310 is provided on the crankshaft 18 that is the output shaft of the internal combustion engine 10 .
Also, the crankshaft 18 is connected to an output shaft 41 of an electric motor 30 via a hydraulic clutch mechanism 20 . The output shaft 41 is provided with a mechanical oil pump (hereinafter referred to as MOP) 50 driven by the electric motor 30 . Vehicle 500 is also provided with electric oil pump (hereinafter referred to as EOP) 80 .

When the clutch mechanism 20 is engaged, the crankshaft 18 and the output shaft 41 of the electric motor 30 are connected. When the clutch mechanism 20 is disengaged, the crankshaft 18 and the output shaft 41 of the electric motor 30 are disconnected.

The electric motor 30 transmits and receives electric power to and from a high-voltage battery 300 for running via a PCU (Power Control Unit) 200 .
The PCU 200 includes a boost converter 210, an inverter 220, a DC-DC converter 230 and the like. Boost converter 210 boosts and outputs the DC voltage input from high voltage battery 300 . Inverter 220 converts the DC voltage boosted by boost converter 210 into an AC voltage and outputs the AC voltage to electric motor 30 . DC-DC converter 230 steps down the DC voltage of high-voltage battery 300 to a voltage for driving accessories.

Vehicle 500 includes low-voltage battery 310 that stores the power stepped down by DC-DC converter 230 . PCU 200 also detects the charging rate SOC of high voltage battery 300 (SOC=remaining capacity of battery [Ah]/fully charged capacity of battery [Ah]×100%) and charging rate SOC of low voltage battery 310 .

An output shaft 41 of the electric motor 30 is connected to an input shaft of a torque converter 42 having a lockup clutch 45 . An output shaft of torque converter 42 is connected to an input shaft of automatic transmission 48 . An output shaft of automatic transmission 48 is connected to differential gear 60 . Drive wheels 65 of vehicle 500 are connected to the output shaft of differential gear 60 .

The vehicle 500 includes a hydraulic adjustment mechanism 90 that uses the MOP 50 and the EOP 80 as hydraulic sources. The hydraulic pressure adjustment mechanism 90 is connected to the automatic transmission 48, the lockup clutch 45, the clutch mechanism 20, and the like as destinations to which hydraulic pressure is supplied. By controlling the hydraulic pressure supplied from the hydraulic pressure adjusting mechanism 90, the shift operation of the automatic transmission 48, the operation of the lockup clutch 45, the operation of the clutch mechanism 20, and the like are controlled.

Various controls such as control of the internal combustion engine 10 , control of the electric motor 30 , and control of the hydraulic pressure adjustment mechanism 90 are executed by a control device 100 mounted on the vehicle 500 .
The control device 100 includes a central processing unit (hereinafter referred to as CPU) 110 and a memory 120 in which control programs and data are stored. Various controls are executed by the CPU 110 executing programs stored in the memory 120 . Although not shown, the control device 100 includes a plurality of control units such as a control unit for the internal combustion engine and a control unit for the PCU.

A crank angle sensor 70 that detects the rotation angle of the crankshaft 18 and a rotation speed sensor 71 that detects a motor rotation speed Nm, which is the rotation speed of the electric motor 30, are connected to the control device 100 . The control device 100 is connected to an airflow meter 72 that detects an intake air amount GA of the internal combustion engine 10 and a water temperature sensor 73 that detects a cooling water temperature THW of the internal combustion engine 10 . Connected to the control device 100 are a throttle sensor 74 for detecting a throttle opening TA, which is the opening of the throttle valve 14, and an accelerator position sensor 75 for detecting an accelerator operation amount ACCP, which is the operation amount of the accelerator pedal. A vehicle speed sensor 76 that detects the vehicle speed SP of the vehicle 500 is connected to the control device 100 . Also connected to the control device 100 is a power switch 77 for the driver of the vehicle 500 to start and stop the system of the vehicle 500 . Based on the input signal from power switch 77 , control device 100 grasps the activation request for the system of vehicle 500 . Control device 100 calculates engine speed Ne based on output signal Scr of crank angle sensor 70 . Further, the control device 100 calculates the engine load factor KL based on the engine rotation speed Ne and the intake air amount GA.

The PCU 200 is connected to the control device 100 , and the control device 100 controls the electric motor 30 through the control of the PCU 200 .
<Regarding the control device>
The control device 100 calculates a vehicle required torque, which is a required value of the driving force of the vehicle 500, from the accelerator operation amount ACCP and the vehicle speed SP. Further, the control device 100 sets the engine required torque, which is the required value of the output torque of the internal combustion engine 10, and the required motor torque, which is the required value of the power running torque of the electric motor 30, based on the vehicle required torque, the state of charge SOC, and the like. Calculate. The control device 100 controls the output of the internal combustion engine 10 in accordance with the engine required torque, and the torque control of the electric motor 30 in accordance with the motor required torque, thereby performing torque control necessary for running the vehicle 500 .

When the internal combustion engine 10 is used as the prime mover of the vehicle 500 , the control device 100 engages the clutch mechanism 20 to transmit the output torque of the internal combustion engine 10 to the automatic transmission 48 . In some cases, the power running torque of the electric motor 30 as well as the output torque of the internal combustion engine 10 is transmitted to the automatic transmission 48 by powering the electric motor 30 as well. On the other hand, when only electric motor 30 is used as the prime mover of vehicle 500 , control device 100 cuts off torque transmission between internal combustion engine 10 and automatic transmission 48 by disengaging clutch mechanism 20 . The power running torque of the electric motor 30 is transmitted to the automatic transmission 48 by powering the electric motor 30 . Thus, when only the electric motor 30 is used as the prime mover of the vehicle 500, the operation of the internal combustion engine 10 is stopped. In this way, while the vehicle 500 is running, intermittent operation and intermittent stop are performed in which the internal combustion engine 10 is repeatedly operated and stopped.

The control device 100 performs regenerative control during coasting (inertia running) when the accelerator is off (accelerator operation amount ACCP is "0") and during braking by depressing the brake pedal. This regenerative control is a control that causes the electric motor 30 to function as a generator by rotating the electric motor 30 using the kinetic energy transmitted from the drive wheels 65, and stores the generated electric power in the high-voltage battery 300. When performing regeneration control, the control device 100 engages the lockup clutch 45 and basically disengages the clutch mechanism 20 to reduce rotational resistance.

When there is a request to start the internal combustion engine 10 , the control device 100 selects one of a plurality of engine start modes, which will be described later, and starts cranking the internal combustion engine 10 . Then, fuel injection and ignition are started to start the engine.

The start request includes an initial start request and an intermittent start request.
The first start request is the first start request after the power switch 77 is turned on, and the electric motor 30 is not yet rotating when the first start request is made.

The intermittent start request is a start request for intermittent operation as described above, and the electric motor 30 is in a rotating state when the intermittent start request is generated. An example of an intermittent start request is a case where a vehicle driving torque that cannot be compensated for by the torque of the electric motor 30 alone is requested while the internal combustion engine 10 is stopped. Examples of intermittent start requests include, for example, a request to charge the high-voltage battery 300 and a request to charge the low-voltage battery 310 .

Then, the control device 100 corrects the amount of fuel to increase during fuel injection at the time of starting the engine.
This fuel increase correction is performed as follows.
That is, the control device 100 calculates the fuel injection amount Q at each predetermined calculation cycle based on the following equation (1) until a predetermined period elapses after starting the engine. Then, the fuel injection valve 12 is controlled so that the calculated fuel injection amount Q is injected.

Fuel injection amount Q=Basic injection amount Qb×Increase coefficient K (1)

The basic injection amount Qb is a value calculated based on the cooling water temperature THW when the engine start request is generated. , the basic injection amount Qb is calculated.

The increase coefficient K is a coefficient for increasing the amount of fuel until a predetermined period elapses after starting the engine, and is set to a value of "1" or more. Then, the increase coefficient K is calculated for each predetermined calculation cycle based on the following equation (2).

Increase coefficient K=previous increase coefficient K×attenuation coefficient Kg (2)

Calculation of the increase initial value Ks, which is the initial value of the increase coefficient K, will be described later.

Calculation of the damping coefficient Kg corresponding to the damping amount for gradually decreasing the fuel increase correction amount will also be described later. Note that the attenuation coefficient Kg is a value larger than "0" and smaller than "1". When the value of the damping coefficient Kg is large, the value of the increase coefficient K calculated from the above equation (2) becomes large compared to when the value of the damping coefficient Kg is small. When the value of the increase coefficient K increases, the value of the fuel injection amount Q calculated from the above equation (1) becomes greater than when the value of the increase coefficient K is small. That is, when the value of the damping coefficient Kg is large, the damping amount per unit time of the increase correction amount of the fuel becomes small.

<Regarding engine start mode>
FIG. 2 shows a first mode, a second mode, a third mode, and a fourth mode, which are a plurality of engine starting modes that the control device 100 implements.

The first mode and the second mode are engine starting modes that are selected at the time of the initial starting when the initial starting request is generated.
The first mode is a mode selected when the cooling water temperature THW is equal to or higher than a predetermined temperature. In the first mode, the clutch mechanism 20 is engaged when an initial start request occurs. When the engagement of the clutch mechanism 20 is completed, the electric motor 30 is driven, so that both the engine rotation speed Ne and the motor rotation speed Nm increase, and the internal combustion engine 10 is cranked. Then, when the engine rotation speed Ne reaches a predetermined rotation speed, the engine is started by starting fuel injection and ignition. In this first mode, the engagement shock of the clutch mechanism 20 is less likely to occur. Further, since fuel injection and ignition are started after the engine rotation speed Ne rises to some extent, the mixing of the air-fuel mixture is facilitated, thereby improving exhaust emissions.

The second mode is a mode selected when the cooling water temperature THW is lower than the predetermined temperature. In the second mode, the clutch mechanism 20 is released when an initial start request occurs. If the clutch mechanism 20 is in the released state at the time when the initial start request is generated, the released state is maintained. Cranking of the internal combustion engine 10 is started by driving the starter motor 85 . Then, when the crank angle of the crankshaft 18 is determined, the engine is started by starting fuel injection and ignition. In this second mode, the starter motor 85 is used for cranking. This is because the torque of the electric motor 30 decreases in a low-temperature environment, making it difficult to increase the engine rotation speed Ne to the predetermined rotation speed described above. Thus, the second mode is a mode for low temperature starting.

The first mode is a control in which fuel injection and ignition are started in a state where the engine speed is higher than in the second mode, the first mode is high rotation start control, and the second mode is low rotation start control. It has become.

The third mode and the fourth mode are engine starting modes that are selected during intermittent starting in response to an intermittent starting request.
The third mode is selected when an intermittent start request is not urgent, such as when a request to charge the high-voltage battery 300 or a request to charge the low-voltage battery 310 occurs. In the third mode, when an intermittent start request occurs, the clutch mechanism 20, which was in the released state, is brought into the slip state. When the clutch mechanism 20 is in a slip state, torque is transmitted from the electric motor 30 to the internal combustion engine 10 and cranking of the internal combustion engine 10 is performed, thereby increasing the engine rotation speed Ne. When the engine rotation speed Ne reaches the motor rotation speed Nm and these rotation speeds are synchronized, the state of the clutch mechanism 20 is changed from the slip state to the engaged state, and fuel injection and ignition are started, thereby starting the engine. is done. In this third mode, synchronization of the clutch mechanism 20 is easy, and shock is less likely to occur at the time of starting.

The fourth mode is selected when there is an urgent intermittent start request, such as when the vehicle drive torque is required that cannot be compensated by the torque of the electric motor 30 alone while the internal combustion engine 10 is not running. mode. In the fourth mode, when an intermittent start request occurs, the clutch mechanism 20, which was in the released state, is brought into the slip state. When the clutch mechanism 20 is in a slip state, torque is transmitted from the electric motor 30 to the internal combustion engine 10, and cranking of the internal combustion engine 10 is started. Then, when the crank angle of the crankshaft 18 is determined, the engine is started by starting fuel injection and ignition. This fourth mode is characterized by a short time from the occurrence of a start request to the actual completion of the engine start, that is, a good start response, although it is difficult to synchronize the clutch mechanism 20 and a shock is likely to occur at the time of start.

The third mode is a control in which fuel injection and ignition are started in a state where the engine speed is higher than in the fourth mode, the third mode is high rotation start control, and the fourth mode is low rotation start control. It has become.

It should be noted that when performing the high rotation start control (first mode and third mode), compared with the case of implementing the low rotation start control (second mode and fourth mode), the engine starting time is reduced. The opening of the throttle valve 14 is adjusted so that the amount of air in the cylinder is reduced. This is to suppress the engine rotation speed from racing when the engine is started by, for example, high-speed starting control.

The high speed start control is characterized in that, for example, the shock at the time of starting the engine is smaller than the low speed start control. In addition, the low speed start control is characterized in that, compared to the high speed start control, the time from the generation of the start request to the actual completion of the engine start is short, that is, the so-called start response is good.

Here, as described above, the amount of air in the cylinder at the time of starting the engine differs between the high rotation start control and the low rotation start control. In addition, when performing the high rotation start control, the number of rotations of the crankshaft 18 from the start of cranking to the start of the engine increases compared to when the low rotation start control is performed. . If the number of rotations of the crankshaft 18 during cranking increases, the amount of fresh air passing through the catalyst 17 increases, so there is a risk that the oxygen storage amount of the catalyst 17 will exceed the appropriate amount.

Therefore, if the initial fuel increase value Ks and the damping coefficient Kg related to the fuel increase correction at engine start are set to be the same for high speed start control and low speed start control, it may become difficult to optimize combustion at engine start. There is

For example, if the increase initial value Ks is made the same, the fuel amount cannot be increased according to the amount of air in the cylinder at the time of starting the engine. As a result, combustion cannot be optimized, and there is a risk that an excess or deficiency of engine torque will occur when the engine is started, causing a shock at the time of start.

Further, if the damping coefficient Kg is made the same between the high speed start control and the low speed start control, the following problems may occur. That is, the oxygen occluded by the catalyst 17 at engine start-up is released when the catalyst 17 is exposed to a reducing atmosphere due to the fuel increase. Therefore, when the catalyst 17 stores a large amount of oxygen when the engine is started, it is desirable to increase the damping coefficient Kg. As described above, when the damping coefficient Kg is increased, the damping amount per unit time of the increase correction amount of the fuel becomes smaller than when the damping coefficient Kg is decreased. This is because when the attenuation amount per unit time decreases, the period during which the fuel amount increase correction is executed becomes longer, and the amount of oxygen released from the catalyst 17 increases.

Therefore, if the damping coefficient Kg is made the same between the high speed start control and the low speed start control, the fuel amount cannot be increased according to the amount of oxygen occluded by the catalyst 17 when starting the engine. Therefore, there is a possibility that the combustion cannot be optimized so that the oxygen storage amount of the catalyst 17 becomes an appropriate amount.

Therefore, the control device 100 executes a process of setting the initial increase value Ks and the damping coefficient Kg to different values for the high rotation start control and the low rotation start control.
<Calculation processing of initial value of increase>
FIG. 3 shows the procedure of calculation processing of the increase initial value Ks executed by the control device 100 . The control device 100 starts executing this process when a request to start the internal combustion engine 10 is generated. In the following description, step numbers are represented by numerals prefixed with "S".

When the process shown in FIG. 3 is started, the control device 100 determines whether or not the current start request is the first start request (S100). Then, if it is determined that it is the first start request (S100: YES), the control device 100 determines whether or not the start mode selected this time is the first mode (S110). Then, if it is determined to be the first mode (S110: YES), the control device 100 calculates an increase initial value Ks based on the first initial value map (S120).

The first initial value map is map data prepared in advance for calculating an optimized increase initial value Ks for starting the engine in the first mode. In this first initial value map, data for calculating the initial increase value Ks based on the cooling water temperature THW when the engine start request is generated and the throttle opening degree TA when the engine is started is recorded. In this first initial value map, the initial increase value Ks is set such that the lower the cooling water temperature THW or the greater the throttle opening TA, the larger the calculated initial increase value Ks. It is The reason why the increase initial value Ks is increased as the cooling water temperature THW is lower is that the amount of fuel contributing to combustion decreases as the cooling water temperature THW is lower. The reason why the increase initial value Ks increases as the throttle opening TA increases is that the amount of air in the cylinder increases as the throttle opening TA increases. This is because it is necessary to supply

If it is determined in the process of S110 that the current mode is not the first mode (S110: NO), the control device 100 calculates the increase initial value Ks based on the second initial value map (S130).
The second initial value map is map data prepared in advance for calculating an optimized increase initial value Ks for starting the engine in the second mode. In this second initial value map, data for calculating the initial increase value Ks based on the cooling water temperature THW when the engine start request is generated and the throttle opening degree TA when the engine is started is recorded. In this second initial value map, the initial increase value Ks is set such that the lower the cooling water temperature THW or the greater the throttle opening TA, the larger the calculated initial increase value Ks. It is

Further, even if the cooling water temperature THW and the throttle opening TA are the same, the increase initial value Ks calculated based on the first initial value map is lower than the increase initial value Ks calculated based on the second initial value map. is preset to be a small value. That is, the initial increase value Ks when the high rotation start control is performed at the time of the first start is calculated to be a smaller value than the initial increase value Ks when the low rotation start control is performed at the time of the first start. be.

When it is determined in the processing of S100 that the first start request is not made (S100: NO), the control device 100 determines whether or not the start mode selected this time is the third mode (S140). If it is determined that the current mode is the third mode (S140: YES), the control device 100 calculates an increase initial value Ks based on the third initial value map (S150).

The third initial value map is map data prepared in advance for calculating an optimized increase initial value Ks for starting the engine in the third mode. This third initial value map is used to calculate the initial increase value Ks based on the cooling water temperature THW when the start request is generated and the intermittent stop time Ts, which is the intermittent stop time before the current start request is generated. data is recorded. In this third initial value map, the initial increase value Ks is set so that the lower the cooling water temperature THW or the longer the intermittent stop time Ts, the larger the calculated initial increase value Ks. It is The reason why the increase initial value Ks is increased as the cooling water temperature THW is lower is that the amount of fuel contributing to combustion decreases as the cooling water temperature THW is lower. The reason why the increase initial value Ks is increased as the intermittent stop time Ts is longer is as follows. That is, the longer the intermittent stop time Ts, the greater the amount of oxygen stored by the catalyst 17 while the engine is stopped. be.

When it is determined in the process of S140 that the current mode is not the third mode (S140: NO), the control device 100 calculates the increase initial value Ks based on the fourth initial value map (S160).
The fourth initial value map is map data prepared in advance for calculating an optimized increase initial value Ks for starting the engine in the fourth mode. In this fourth initial value map, data for calculating the increase initial value Ks based on the cooling water temperature THW and the intermittent stop time Ts when the start request is generated is recorded. In this fourth initial value map, the initial increase value Ks is set such that the lower the cooling water temperature THW or the longer the intermittent stop time Ts, the larger the calculated initial increase value Ks. It is

Further, even if the cooling water temperature THW and the intermittent stop time Ts are the same, the increase initial value Ks calculated based on the third initial value map is lower than the increase initial value Ks calculated based on the fourth initial value map. is preset to be a small value. That is, the initial increase value Ks when the high rotation start control is performed during the intermittent start is calculated to be smaller than the initial increase value Ks when the low rotation start control is performed during the intermittent start. be.

Then, when one of the processes of S120, S130, S150, and S160 ends, the control device 100 ends this process.
<Attenuation coefficient calculation processing>
FIG. 4 shows the procedure for calculating the damping coefficient Kg executed by the control device 100 . When a request to start the internal combustion engine 10 is generated, the control device 100 repeatedly executes this process at predetermined calculation intervals. It should be noted that execution of this process is terminated when a predetermined termination condition for terminating the fuel increase at the time of starting is satisfied.

When the process shown in FIG. 4 is started, the control device 100 determines whether or not the current start request is the first start request (S200). Then, if it is determined that it is the first start request (S200: YES), the control device 100 determines whether or not the start mode selected this time is the first mode (S210). When determining that the mode is the first mode (S210: YES), the control device 100 calculates the damping coefficient Kg based on the first damping coefficient map (S220).

The first damping coefficient map is map data prepared in advance for calculating the damping coefficient Kg optimized for starting the engine in the first mode. The first damping coefficient map records data for calculating the damping coefficient Kg based on the cooling water temperature THW obtained in each execution cycle of this process. In this first damping coefficient map, the value of the damping coefficient Kg is set so that the calculated damping coefficient Kg increases as the cooling water temperature THW decreases. The reason why the damping coefficient Kg is increased as the cooling water temperature THW is lower is that the amount of fuel that contributes to combustion decreases as the cooling water temperature THW is lower, so it is necessary to perform fuel amount increase correction for a longer period of time. is.

When it is determined in the process of S210 that the mode is not the first mode (S210: NO), the control device 100 calculates the damping coefficient Kg based on the second damping coefficient map (S230).
The second damping coefficient map is map data prepared in advance for calculating the damping coefficient Kg optimized for starting the engine in the second mode. The second damping coefficient map records data for calculating the damping coefficient Kg based on the cooling water temperature THW obtained in each execution cycle of this process. In the second damping coefficient map, the value of the damping coefficient Kg is set such that the lower the coolant temperature THW, the larger the calculated damping coefficient Kg.

Further, even if the cooling water temperature THW is the same, the damping coefficient Kg calculated based on the first damping coefficient map is set to a value larger than the damping coefficient Kg calculated based on the second damping coefficient map. , is preset. That is, the damping coefficient Kg when the high rotation start control is performed at the initial start is calculated to be a larger value than the damping coefficient Kg when the low rotation start control is performed at the time of the initial start.

When it is determined in the processing of S200 that the first start request is not made (S200: NO), the control device 100 determines whether or not the start mode selected this time is the third mode (S240). Then, if it is determined that the mode is the third mode (S240: YES), the control device 100 calculates the damping coefficient Kg based on the third damping coefficient map (S250).

The third damping coefficient map is map data prepared in advance for calculating the damping coefficient Kg optimized for starting the engine in the third mode. The third damping coefficient map records data for calculating the damping coefficient Kg based on the cooling water temperature THW and the intermittent stop time Ts obtained in each execution cycle of this process. In the third damping coefficient map, the value of the damping coefficient Kg is set such that the lower the cooling water temperature THW or the longer the intermittent stop time Ts, the larger the calculated damping coefficient Kg. there is The reason why the damping coefficient Kg is increased as the cooling water temperature THW is lower is that the amount of fuel that contributes to combustion decreases as the cooling water temperature THW is lower, so it is necessary to perform fuel amount increase correction for a longer period of time. is. The reason why the damping coefficient Kg is increased as the intermittent stop time Ts is longer is as follows. That is, the longer the intermittent stop time Ts, the greater the amount of oxygen stored in the catalyst 17 while the engine is stopped. Because it is necessary.

If it is determined in the process of S240 that the mode is not the third mode (S240: NO), the control device 100 calculates the damping coefficient Kg based on the fourth damping coefficient map (S260).
The fourth damping coefficient map is map data prepared in advance for calculating the damping coefficient Kg optimized for starting the engine in the fourth mode. The fourth damping coefficient map records data for calculating the damping coefficient Kg based on the cooling water temperature THW and the intermittent stop time Ts obtained in each execution cycle of this process. In the fourth damping coefficient map, the value of the damping coefficient Kg is set such that the lower the cooling water temperature THW or the longer the intermittent stop time Ts, the larger the calculated damping coefficient Kg. there is

Further, even if the cooling water temperature THW and the intermittent stop time Ts are the same, the damping coefficient Kg calculated based on the third damping coefficient map is larger than the damping coefficient Kg calculated based on the fourth damping coefficient map. It is set in advance so as to be a value. That is, the damping coefficient Kg when high speed start control is performed during intermittent start is calculated to be a larger value than the damping coefficient Kg when low speed start control is performed during intermittent start.

After completing any one of the processes of S220, S230, S250, and S260, the control device 100 once ends this process.
<Action and effect>
According to this embodiment, the following actions and effects are obtained.

(1) As described above, when performing the high rotation start control (first mode and third mode), compared to when performing the low rotation start control (second mode and fourth mode), the engine There is less air in the cylinder when the engine starts. Therefore, the initial increase value Ks, which is set when the high-speed start control is performed so that the amount of air in the cylinder when starting the engine is smaller than when the low-speed start control is performed, is set when the low-speed start control is performed. is calculated to be smaller than the value of the initial increase value Ks. Therefore, the amount of fuel is corrected to increase in accordance with the amount of air in the cylinder when the engine is started. can be optimized.

(2) As described above, when performing the high rotation start control (the first mode and the third mode), compared to when performing the low rotation start control (the second mode and the fourth mode), the catalyst There is a risk that the oxygen storage amount of 17 will be greater than the appropriate amount. Therefore, the damping coefficient Kg set during execution of the high rotation start control is calculated so as to be larger than the value of the damping coefficient Kg set during execution of the low rotation start control. Therefore, the amount of fuel is increased according to the amount of oxygen stored in the catalyst 17 when the engine is started, and combustion can be optimized so that the amount of oxygen stored in the catalyst 17 is appropriate.

<Change example>
It should be noted that the above embodiment can be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other within a technically consistent range.

- The throttle opening TA and the intermittent stop time Ts may be omitted when calculating the initial increase value Ks.
- The intermittent stop time Ts may be omitted when calculating the damping coefficient Kg.

- The initial value of increase Ks and the damping coefficient Kg may be calculated by a functional expression.
- Either one of the increase initial value Ks and the damping coefficient Kg may be different between the high rotation start control and the low rotation start control.

- The hybrid system of the vehicle 500 is not limited to that shown in FIG. 1, and may be another hybrid system.
- The control device 100 includes a CPU 110 and a memory 120, and is not limited to executing software processing. For example, a dedicated hardware circuit (such as an ASIC, for example) that processes at least part of the software processing performed in the above embodiments may be provided. That is, the control device 100 may have any one of the following configurations (a) to (c). (a) A processing device that executes all of the above processes according to a program, and a program storage device such as a memory that stores the program. (b) A processing device and a program storage device for executing part of the above processing according to a program, and a dedicated hardware circuit for executing the remaining processing. (c) provide dedicated hardware circuitry to perform all of the above processing; Here, there may be a plurality of software processing circuits including a processing device and a program storage device, or a plurality of dedicated hardware circuits. That is, the processing may be performed by a processing circuit comprising at least one of one or more software processing circuits and one or more dedicated hardware circuits.

REFERENCE SIGNS LIST 10 internal combustion engine 12 fuel injection valve 13 intake passage 14 throttle valve 16 exhaust passage 17 catalyst 18 crankshaft 20 clutch mechanism 30 electric motor 42 torque converter 45 lockup clutch 48 automatic transmission 50 ...Mechanical oil pump 60...Differential gear 65...Drive wheel 80...Electric oil pump 85...Starter motor 90...Hydraulic adjustment mechanism 100...Control device 110...Central processing unit 120...Memory 200...PCU
500...Vehicle

Claims (1)

A control device for performing a fuel amount increase correction when starting an internal combustion engine having a catalyst in an exhaust passage,
Selecting either one of the high rotation start control and the low rotation start control at engine start,
The high rotation start control is control for starting fuel injection and ignition in a state where the engine rotation speed is higher than that in the low rotation start control,
A control device for an internal combustion engine that sets at least one of an initial value of the increase correction and an attenuation amount of the increase correction to different values for the high rotation start control and the low rotation start control.

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