JP7188158B2 - Vehicle internal combustion engine controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle-mounted internal combustion engine that executes fuel cut processing when a vehicle decelerates.

Patent Literature 1 describes an example of a control device that executes a fuel cut process that halts combustion in a cylinder by stopping fuel injection from a fuel injection valve during deceleration of a vehicle. In this control device, the opening of the throttle valve is increased when the duration of the fuel cut process exceeds a predetermined time. As a result, the intake pipe negative pressure, which is the negative pressure downstream of the throttle valve in the intake passage, is reduced. As a result, it is suppressed that the pressure in the cylinder decreases during the expansion stroke, so that oil is suppressed from flowing into the cylinder from the crankcase side.

JP 2015-83812 A

If the opening of the throttle valve is increased during execution of the fuel cut process, engine braking may decrease and the deceleration of the vehicle may change. Unless the amount of increase in the opening of the throttle valve is too large in order to suppress the deterioration of the engine brake, the negative pressure in the intake pipe cannot be reduced sufficiently during the execution of the fuel cut process, and oil does not flow into the cylinder. There is a risk that the inflow cannot be sufficiently suppressed.

A control device for an on-vehicle internal combustion engine for solving the above problems includes a control unit that executes a fuel cut process that suspends combustion in all cylinders when prescribed fuel cut conditions are satisfied during deceleration of the vehicle. I have. In this control device, the control unit temporarily suspends the fuel cut process and executes a firing process for injecting fuel from the fuel injection valve to cause combustion in the cylinder.

Even when combustion in each cylinder is stopped by execution of the fuel cut process, the piston reciprocates in each cylinder. When the piston reciprocates while combustion is stopped in the cylinder, the piston ring attached to the piston displaces within the ring groove of the piston as follows.

That is, when the piston is moving toward the bottom dead center in the intake stroke, the piston ring is displaced toward the combustion chamber within the ring groove. When the piston moves toward the top dead center in the compression stroke following the intake stroke, the piston ring is displaced toward the crankcase in the ring groove. When the piston moves toward the bottom dead center in the expansion stroke following the compression stroke, the piston ring is displaced in the ring groove toward the combustion chamber. When the piston moves toward the top dead center in the exhaust stroke following the compression stroke, the piston ring is displaced toward the crankcase in the ring groove.

Also, when the fuel cut process is being executed, oil may flow into the combustion chamber from the crankcase side. Such an event is caused by repeated displacement of the piston ring toward the combustion chamber side and displacement of the piston ring toward the crankcase in the ring groove as described above during execution of the fuel cut process. It is presumed that the cause is that the oil is pumped up to the combustion chamber side through the ring groove.

According to the above configuration, even when the fuel cut condition is satisfied, the fuel cut process is temporarily interrupted and the firing process is executed. Combustion is performed in the cylinder during execution of the firing process. When combustion takes place in the cylinder, the pressure in the combustion chamber increases due to the combustion, so when the piston is moving toward the bottom dead center in the expansion stroke, the piston ring moves toward the crankcase side in the ring groove. It is possible to maintain a state of contact with the wall surface. As a result, as the piston moves toward the bottom dead center in the expansion stroke, it is possible to prevent oil from entering the ring groove and to scrape off the oil by the piston ring. By restarting the fuel cut process after the oil is scraped off in this way, it becomes difficult for the oil to flow into the combustion chamber.

Therefore, it is possible to prevent oil from flowing into the combustion chamber from the crankcase side during execution of the fuel cut process.
The lower the oil temperature, the higher the viscosity of the oil. As a result of conducting various experiments and simulations, the inventors of the present application found that the higher the viscosity of the oil, the easier it is for the oil to flow into the combustion chamber due to the repeated reciprocating motion of the piston ring in the ring groove. I got the knowledge that Therefore, it is preferable that the lower the oil temperature, the more frequently the control unit temporarily suspends the fuel cut process and executes the firing process.

According to the above configuration, when the fuel cut process is executed under the condition that the viscosity of the oil is estimated to be high, the fuel cut process is temporarily interrupted and the firing process is executed more frequently. As a result, even if the viscosity of the oil is high, it is possible to suppress the oil from flowing into the combustion chamber from the crankcase side during execution of the fuel cut process.

It is presumed that the longer the duration of the fuel cut process, the more likely it is that oil pumped up by repeated reciprocating motions of the piston ring within the ring groove as described above will flow into the combustion chamber. Therefore, in one aspect of a control device for a vehicle-mounted internal combustion engine, the control unit temporarily interrupts the fuel cut process and starts the firing process on condition that the duration of the fuel cut process reaches the determination duration time. Run.

According to the above configuration, even if the fuel cut condition continues to be satisfied for a long period of time, when the duration of the fuel cut process reaches the determination duration time, the fuel cut process is temporarily interrupted and the firing process is executed. be. Therefore, even if the fuel cut condition continues to be satisfied for a long period of time, it is possible to prevent oil from flowing into the combustion chamber from the crankcase side.

One aspect of a control device for a vehicle-mounted internal combustion engine includes a frequency adjustment unit that shortens the determination continuation time as the oil temperature or the correlation value of the oil temperature is lower. According to this configuration, the lower the oil temperature and the higher the oil viscosity, the shorter the determination continuation time. Therefore, it is possible to realize a configuration in which the lower the oil temperature, the more frequently the fuel cut process is temporarily interrupted and the firing process is executed.

As the negative pressure downstream of the throttle valve in the intake passage increases, the pressure in the combustion chamber tends to decrease. The lower the pressure in the combustion chamber, the easier it is for oil to flow into the combustion chamber from the crankcase through the ring groove. Therefore, the longer the duration of the state in which the negative pressure downstream of the throttle valve in the intake passage is greater, the more likely it is that oil will flow into the combustion chamber due to the repeated reciprocating motion of the piston ring in the ring groove. presumed to occur easily. Therefore, in one aspect of a control device for a vehicle-mounted internal combustion engine, the control unit determines the duration of a state in which the negative pressure downstream of the throttle valve in the intake passage is equal to or higher than the determination negative pressure during execution of the fuel cut process. On the condition that the negative pressure continuation time is reached, the fuel cut process is temporarily interrupted and the firing process is executed.

According to the above configuration, even if the fuel cut condition continues to be satisfied for a long period of time, the duration of the state in which the negative pressure downstream of the throttle valve in the intake passage is equal to or higher than the determination negative pressure reaches the determination duration. , the fuel cut process is temporarily interrupted and the firing process is executed. Therefore, even if the fuel cut condition continues to be satisfied for a long period of time, it is possible to prevent oil from flowing into the combustion chamber from the crankcase side.

One aspect of a control device for a vehicle-mounted internal combustion engine includes a frequency adjustment unit that shortens the determined negative pressure continuation time as the oil temperature or the correlation value of the oil temperature is lower. According to this configuration, the lower the oil temperature and the higher the oil viscosity, the shorter the determination negative pressure continuation time. Therefore, it is possible to realize a configuration in which the lower the oil temperature, the more frequently the fuel cut process is temporarily interrupted and the firing process is executed.

Note that when the fuel cut process is temporarily interrupted and the firing process is performed, it is presumed that the higher the viscosity of the oil, the more difficult it is to scrape off the oil with the piston ring during the firing process. Therefore, in one aspect of a control device for an in-vehicle internal combustion engine, when the fuel cut process is temporarily suspended and the firing process is executed, the lower the oil temperature, the longer the execution time of the firing process. .

According to the above configuration, even if the oil temperature is low and the oil viscosity is high, the oil can be scraped off by the piston ring during the firing process by extending the execution time of one firing process. . As a result, it is possible to suppress the oil from flowing into the combustion chamber from the crankcase side during execution of the fuel cut process when the viscosity of the oil is high.

In one aspect of a control device for an on-vehicle internal combustion engine, when one of all cylinders is set as a target cylinder, the target cylinder during one cycle of the on-vehicle internal combustion engine during a period in which the fuel cut process is temporarily interrupted Firing processing, in which combustion is performed only in the cylinder selected as , is sequentially performed for all cylinders while changing the target cylinder. According to this configuration, under the condition that the fuel cut condition is satisfied, it is possible to sequentially change the cylinder in which combustion is performed by executing the filing process.

Further, in one aspect of the control device for a vehicle-mounted internal combustion engine, the firing process is a process of causing combustion in each cylinder during one cycle of the vehicle-mounted internal combustion engine and ending the process. When such filing processing is executed, combustion is performed in all cylinders in one cycle in the vehicle internal combustion engine. Therefore, by temporarily interrupting the fuel cut process and executing the firing process, it is less likely that oil will flow into each cylinder from the crankcase side.

A catalytic converter having an oxygen storage function is sometimes provided in an exhaust passage of an internal combustion engine. In such an internal combustion engine, when unburned fuel is supplied to the catalytic converter, oxygen stored in the catalytic converter reacts with the unburned fuel. The reaction then causes the temperature of the catalytic converter to rise.

When the fuel cut process is being executed, the intake air flows into the catalytic converter as it is, so the temperature of the catalytic converter tends to drop.
Therefore, in the firing process, the control unit preferably causes the fuel injection valve to inject an amount of fuel larger than the stoichiometric injection amount, which is the fuel injection amount that makes the air-fuel ratio stoichiometric. According to this configuration, unburned fuel can be supplied to the catalytic converter by executing the firing process even when the fuel cut condition is satisfied. When the unburned fuel is supplied to the catalytic converter, oxygen stored in the catalytic converter reacts with the unburned fuel, so that the temperature of the catalytic converter can be raised. As a result, it is possible to suppress a decrease in the temperature of the catalytic converter while the fuel cut condition is satisfied.

1 is a diagram showing a functional configuration of a control device for a vehicle-mounted internal combustion engine and a schematic configuration of an internal combustion engine controlled by the control device according to the first embodiment; FIG. FIG. 4 is a schematic diagram showing a state in which a piston of the internal combustion engine is moving toward bottom dead center during execution of fuel cut processing; FIG. 4 is a schematic diagram showing how the piston moves toward the top dead center during execution of the fuel cut process; FIG. 5 is a schematic diagram showing how oil prevents the piston ring from contacting the wall surface of the ring groove while the piston is moving toward the bottom dead center during execution of the fuel cut process. FIG. 5 is a schematic diagram showing how oil prevents the piston ring from contacting the wall surface of the ring groove while the piston is moving toward the top dead center during execution of the fuel cut process. 4 is a flowchart for explaining a processing routine that is executed while the vehicle is running; A map showing the relationship between oil temperature and determination negative pressure duration. 4 is a flowchart for explaining a processing routine executed when firing processing is executed; FIG. 4 is a schematic diagram showing a state in which the piston moves toward the bottom dead center during the expansion stroke during execution of the firing process; 4 is a timing chart for explaining a case where fuel cut processing is temporarily interrupted and firing processing is executed in the first embodiment; 10 is a flowchart for explaining a processing routine that is executed while the vehicle is running in the second embodiment; A map showing the relationship between oil temperature and determination duration. FIG. 11 is a timing chart for explaining a case where the fuel cut process is temporarily interrupted and the firing process is executed in the third embodiment; FIG.

(First embodiment)
A first embodiment of a vehicle internal combustion engine control apparatus will be described below with reference to FIGS. 1 to 10. FIG.
FIG. 1 shows a control device 60 of the present embodiment and an internal combustion engine 10 controlled by the control device 60. As shown in FIG. The internal combustion engine 10 is mounted on the vehicle and functions as a power source of the vehicle.

The internal combustion engine 10 has a plurality of cylinders 11 (only one is shown in FIG. 1). A reciprocating piston 12 is provided in each cylinder 11 . A space above the piston 12 in each cylinder 11 serves as a combustion chamber 13 . Each piston 12 is connected to a crankshaft 15 via a connecting rod 14 . The crankshaft 15 is arranged inside the crankcase 16 . An oil pan 17 that stores oil is provided below the crankcase 16 .

An intake passage 18 of the internal combustion engine 10 is provided with a throttle valve 19 that adjusts the amount of intake air flowing through the intake passage 18 . When the intake valve 20 is open, intake air is introduced into the combustion chamber 13 through the intake passage 18 .

The internal combustion engine 10 is provided with a fuel injection valve 21 that injects fuel. FIG. 1 shows an in-cylinder injection valve that directly injects fuel into the combustion chamber 13 as the fuel injection valve 21 . The internal combustion engine 10 is also provided with an ignition device 22 that ignites a mixture containing intake air and fuel by spark discharge. The same number of fuel injection valves 21 and ignition devices 22 as the number of cylinders are provided. Exhaust gas generated in the combustion chamber 13 by combustion of the air-fuel mixture is discharged to the exhaust passage 24 when the exhaust valve 23 is open. A catalytic converter 25 of an exhaust purification device is provided in the exhaust passage 24 . The catalytic converter 25 has both a function of storing oxygen and a function of oxidizing unburned fuel.

As shown in FIGS. 1 and 2, a plurality of piston rings 30 are attached to the piston 12 . Specifically, as shown in FIG. 2, when the direction in which the piston 12 reciprocates is the piston moving direction Z, a plurality of ring grooves 40 are provided in the side wall 121 of the piston 12 along the piston moving direction Z. It is A piston ring 30 is accommodated in each ring groove 40 . The outer peripheral surface 31 of each piston ring 30 is in pressure contact with the inner peripheral surface 111 of the cylinder 11 . On the other hand, there is a small gap between the inner peripheral surface 32 of each piston ring 30 and the bottom surface 41 of the ring groove 40 . Also, the width of the piston ring 30 , which is the dimension of the piston ring 30 in the piston movement direction Z, is narrower than the width of the ring groove 40 . Therefore, the piston ring 30 can be displaced in the piston moving direction Z within the ring groove 40 .

In this embodiment, a fuel cut process (a fuel cut process ( hereinafter also referred to as “F/C processing”) is executed. Since the crankshaft 15 is rotating during execution of the F/C process, the piston 12 is reciprocating in each cylinder 11 . During F/C processing, oil may flow into the combustion chamber 13 through each ring groove 40 of the piston 12 .

With reference to FIGS. 2 and 3, the assumed flow of oil flowing into the combustion chamber 13 from the crankcase 16 side during F/C processing will be described.
In the intake stroke, the piston 12 moves toward the bottom dead center as indicated by the white arrow in FIG. In this case, in each ring groove 40, the piston ring 30 is displaced toward the combustion chamber 13 (upper side in the drawing). Then, as shown by solid line arrows in FIG. Oil flows in from the case 16 side (lower side in the drawing).

In the compression stroke following the intake stroke, the piston 12 moves toward the top dead center as indicated by the white arrow in FIG. In this case, within each ring groove 40, the piston ring 30 is displaced toward the crankcase 16 side. Then, the oil interposed between the crankcase 16 side wall surface 43 and the piston ring 30 in the ring groove 40 passes between the inner peripheral surface 32 of the piston ring 30 and the bottom surface 41 of the ring groove 40. , moves between the wall surface 42 on the side of the combustion chamber 13 and the piston ring 30 in the ring groove 40 .

In the expansion stroke following the compression stroke, the piston 12 moves toward the bottom dead center as indicated by the white arrow in FIG. Since combustion is not performed in the combustion chamber 13 during execution of the F/C process, the piston ring 30 is displaced toward the combustion chamber 13 in each ring groove 40 as in the intake stroke. Then, as indicated by the solid line arrows in FIG. 2, the oil in the ring groove 40 is pushed out toward the combustion chamber 13 by the piston ring 30, and the oil flows into the ring groove 40 from the crankcase 16 side. flows in.

In the exhaust stroke following the expansion stroke, the piston 12 moves toward the top dead center as indicated by the white arrow in FIG. In this case, the piston ring 30 is displaced toward the crankcase 16 in each ring groove 40, as in the case of the compression stroke. Then, the oil interposed between the crankcase 16 side wall surface 43 and the piston ring 30 in the ring groove 40 passes between the inner peripheral surface 32 of the piston ring 30 and the bottom surface 41 of the ring groove 40. , moves between the wall surface 42 on the side of the combustion chamber 13 and the piston ring 30 in the ring groove 40 .

That is, when the F/C process is performed, in each ring groove 40, displacement of the piston ring 30 toward the combustion chamber 13 and displacement of the piston ring 30 toward the crankcase 16 are repeated. It is presumed that when such reciprocating displacement of the piston ring 30 is repeated many times, the oil may pass through the ring groove 40 and flow into the combustion chamber 13 .

By the way, during execution of the F/C process, the higher the viscosity of the oil, the easier it is for the oil to pass through the ring groove 40 and flow into the combustion chamber 13 from the crankcase 16 side. The reason for this will be explained below.

When the oil temperature is high and the viscosity of the oil is low, when the piston 12 moves toward the bottom dead center such as in the intake stroke or the expansion stroke, the piston ring 30 is compressed in the ring groove 40 as shown in FIG. It is pressed against the wall surface 42 on the chamber 13 side. When the piston ring 30 is pressed against the wall surface 42, the flow of oil flowing out from the ring groove 40 toward the combustion chamber 13 is blocked. When the piston 12 moves toward the top dead center, such as in the compression stroke or the exhaust stroke, the piston ring 30 is pressed against the wall surface 43 of the ring groove 40 on the crankcase 16 side, as shown in FIG. When the piston ring 30 is pressed against the wall surface 43, the flow of oil from the crankcase 16 side into the ring groove 40 is blocked. When the piston rings 30 repeatedly contact the wall surfaces 42 and the piston rings 30 contact the wall surfaces 43 during the reciprocating motion of the piston 12, the flow of oil toward the combustion chamber 13 is repeatedly interrupted. Therefore, the frequency of oil flowing into the combustion chamber 13 from the crankcase 16 side during F/C processing is not so high.

On the other hand, when the oil temperature is low and the oil viscosity is high, the dynamic viscosity coefficient of the oil is high. That is, when the piston 12 moves toward the bottom dead center as in the intake stroke or the expansion stroke, although the piston ring 30 moves toward the combustion chamber 13, the oil intervening between the piston ring 30 and the wall surface 42 causes , the contact between the piston ring 30 and the wall surface 42 is prevented. That is, when the piston 12 moves toward the bottom dead center, the oil having a high kinematic viscosity maintains a state in which a gap is interposed between the piston ring 30 and the wall surface 42 as shown in FIG. . In this case, the flow of oil flowing out from the ring groove 40 toward the combustion chamber 13 is not interrupted.

When the piston 12 moves toward the top dead center as in the compression stroke or the exhaust stroke, the piston ring 30 moves toward the crankcase 16, but the oil interposed between the piston ring 30 and the wall surface 43 causes the piston to move. Abutment between the ring 30 and the wall surface 43 is prevented. That is, when the piston 12 moves toward the top dead center, the oil having a high kinematic viscosity maintains a state in which a gap is interposed between the piston ring 30 and the wall surface 43 as shown in FIG. . In this case, the flow of oil flowing into the ring groove 40 from the crankcase 16 side is not interrupted. If the flow of oil toward the combustion chamber 13 is not blocked during the reciprocating motion of the piston 12 in this way, F During the /C process, oil frequently flows into the combustion chamber 13 from the crankcase 16 side.

As shown in FIG. 1 , detection signals from various sensors such as a pressure sensor 101 , an oil temperature sensor 102 , a crank angle sensor 103 and an accelerator opening sensor 104 are input to the control device 60 . The pressure sensor 101 detects the pressure downstream of the throttle valve 19 in the intake passage 18 and outputs a signal corresponding to the pressure. The oil temperature sensor 102 detects an oil temperature TMP, which is the temperature of oil circulating in the internal combustion engine 10, and outputs a signal corresponding to the oil temperature TMP. Crank angle sensor 103 outputs a signal corresponding to engine rotation speed NE, which is the rotation speed of crankshaft 15 . The accelerator opening sensor 104 detects an accelerator opening AC, which is the operation amount of the accelerator pedal of the vehicle, and outputs a signal corresponding to the accelerator opening AC. The control device 60 controls each fuel injection valve 21 and each ignition device 22 based on the detection signals output from the various sensors 101-104.

The control device 60 has a control section 61, a condition establishment determination section 62, and a frequency adjustment section 63 as functional sections.
The control unit 61 executes the F/C process when a prescribed F/C condition is satisfied. However, if the F/C condition is not established during execution of the F/C process, the control unit 61 terminates the F/C process and controls each fuel injection valve 21 and each ignition device 22 to Combustion in each cylinder 11 is restarted. Further, when a firing flag FLG, which will be described later, is set to ON while the F/C condition is satisfied, the control unit 61 temporarily suspends the F/C process and executes the firing process. After completing the firing process, the control unit 61 restarts the F/C process. Note that the firing process will be described later.

The condition establishment determination unit 62 determines whether or not a condition for permitting execution of the firing process is established during execution of the F/C process. Then, when the condition for permitting execution of the firing process is satisfied, the condition satisfaction determining unit 62 sets the firing flag FLG to ON.

The frequency adjustment unit 63 adjusts the execution frequency of the firing process during the period in which the F/C condition is satisfied. In the present embodiment, the frequency adjusting unit 63 increases the execution frequency of the firing process as the oil temperature TMP is lower. That is, the lower the oil temperature TMP, the easier it is for the firing flag FLG to be set to ON. A method of adjusting the execution frequency will be described later.

Next, with reference to FIGS. 6 and 7, a processing routine executed by the condition establishment determining section 62 of the control device 60 while the vehicle is running will be described. This processing routine is a routine for setting the firing flag FLG to ON. Therefore, this processing routine is repeatedly executed while the vehicle is running when the firing flag FLG is set to OFF.

As shown in FIG. 6, in the first step S11 of this processing routine, it is determined whether or not the F/C condition is satisfied. That is, the condition establishment determination unit 62 determines that the F/C condition is established when both the engine rotation speed NE is greater than the determination rotation speed NETh and the accelerator operation is not performed. determined to be The determination rotation speed NETh is set, for example, to a value slightly higher than the engine rotation speed NE during idling. Further, the condition establishment determining unit 62 determines that the accelerator operation is not performed when the accelerator opening AC is "0". If the F/C condition is satisfied, the F/C process is being executed by the control unit 61 . On the other hand, when the F/C condition is not satisfied, the F/C process is not executed and combustion is performed in each cylinder 11 .

If it is not determined in step S11 that the F/C condition is satisfied (NO), the process proceeds to step S15. On the other hand, if it is determined that the F/C condition is established (S11: YES), the process proceeds to the next step S13.

In step S13, it is determined whether or not the intake pipe negative pressure NPmc, which is the negative pressure downstream of the throttle valve 19 in the intake passage 18, is equal to or higher than the determination negative pressure NPTh. The intake pipe negative pressure NPmc can be derived based on the pressure downstream of the throttle valve 19 in the intake passage 18 detected by the pressure sensor 101 . For example, if the pressure is absolute pressure, the intake pipe negative pressure NPmc takes a positive value when the pressure is lower than the atmospheric pressure. That is, the lower the pressure, the higher the intake pipe negative pressure NPmc.

When the F/C process is being performed, the throttle opening, which is the opening of the throttle valve 19, is the throttle opening during idling or a value close to the throttle opening during idling. Furthermore, the engine speed NE during F/C processing is higher than the engine speed NE during idling. Therefore, during execution of the F/C process, the intake pipe negative pressure NPmc tends to increase. Since the pressure in the combustion chamber 13 tends to decrease as the intake pipe negative pressure NPmc increases, oil tends to flow into the combustion chamber 13 through the ring grooves 40 during F/C processing. Therefore, the determination negative pressure NPTh is set as a criterion for determining whether the intake pipe negative pressure NPmc is large.

In step S13, if the intake pipe negative pressure NPmc is equal to or higher than the determination negative pressure NPTh (YES), the process proceeds to the next step S14. In step S14, the duration TM1 of the state in which the determination result is "YES" in all of steps S11 and S13 is updated. Then, the process proceeds to step S16, which will be described later. On the other hand, in step S13, if the intake pipe negative pressure NPmc is less than the determination negative pressure NPTh (NO), the process proceeds to the next step S15.

At step S15, the duration TM1 is reset to "0". This is because the F/C process is not executed or the intake pipe negative pressure NPmc is less than the determination negative pressure NPTh. After that, this processing routine is temporarily terminated.

In step S16, it is determined whether or not the updated duration time TM1 is equal to or greater than the determination negative pressure duration time TMTh1. The phenomenon in which oil flows into the combustion chamber 13 through each ring groove 40 is more likely to occur as the duration TM1 is longer. Therefore, the determination negative pressure continuation time TMTh1 is set as a criterion for determining whether there is a possibility that oil flows into the combustion chamber 13 through each ring groove 40 or not. Therefore, when the duration time TM1 is equal to or longer than the determination negative pressure duration time TMTh1, it can be determined that there is a possibility that oil flows into the combustion chamber 13 through the ring grooves 40 .

In the present embodiment, the determination negative pressure continuation time TMTh1 is adjusted by the frequency adjuster 63. FIG. That is, as described above, the lower the oil temperature TMP and the higher the viscosity of the oil, the easier it is for the oil to flow into the combustion chamber 13 through the ring grooves 40 . Therefore, the frequency adjustment unit 63 sets the determination negative pressure continuation time TMTh1 such that the lower the oil temperature TMP, the shorter the determination negative pressure duration time TMTh1. For example, the frequency adjustment unit 63 sets the determination negative pressure duration time TMTh1 using the map shown in FIG.

The map shown in FIG. 7 is a map showing the relationship between the oil temperature TMP and the determined negative pressure duration time TMTh1. In this map, the higher the oil temperature TMP, the longer the determination negative pressure continuation time TMTh1.
Returning to FIG. 6, in step S16, if the duration time TM1 is equal to or longer than the determined negative pressure duration time TMTh1 (YES), the process proceeds to the next step S17. In this embodiment, if the determinations in steps S13 and S16 are both "YES", it can be determined that the conditions for permitting execution of the firing process have been met. Therefore, in step S17, the firing flag FLG is set to ON. Then, this processing routine ends. In this case, the execution of this processing routine is suspended until the firing process is executed and the firing flag FLG is set to OFF, as will be described later in detail. On the other hand, if the duration time TM1 is less than the determined negative pressure duration time TMTh1 (S16: NO), this processing routine is temporarily terminated without performing the processing of step S17. That is, in this case, the firing flag FLG remains set to OFF.

Next, referring to FIG. 8, a processing routine executed by the control unit 61 when the firing flag FLG is set to ON during execution of the F/C process will be described.
In this processing routine, in step S21, a target cylinder, which is a target cylinder for firing processing, is selected from among the cylinders 11 of the internal combustion engine 10 . Here, it is assumed that the number of cylinders of the internal combustion engine 10 is three. When the execution of this processing routine is started and the processing of step S21 is performed for the first time, the first cylinder #1 of the cylinders 11 is selected as the target cylinder.

Subsequently, in step S22, the firing process for the target cylinder is executed. The firing process is a process of supplying fuel to the cylinder 11 selected as the target cylinder and causing combustion to occur in the combustion chamber 13 of the cylinder 11 . For example, when the target cylinder is the first cylinder #1, in the firing process, fuel is injected from the fuel injection valve 21 for the first cylinder #1 and the ignition device 22 for the first cylinder #1 is operated. , to burn the air-fuel mixture in the combustion chamber 13 of the first cylinder #1. In cylinders other than the target cylinder (in this case, the second cylinder #2 and the third cylinder #3), fuel supply and ignition are not performed, and combustion is not performed. That is, in the present embodiment, when the conditions for permitting execution of the firing process are met, that is, when the firing flag FLG is set to ON, the control unit 61 temporarily interrupts the F/C process to Firing processing is executed in cylinder 11 . After completing the firing process, the control unit 61 restarts the F/C process.

Incidentally, in the firing process, the fuel injection valve 21 is controlled such that the fuel injection amount of the fuel injection valve 21 that supplies fuel to the target cylinder is greater than the stoichiometric injection amount. The stoichiometric injection amount is a fuel injection amount that makes the air-fuel ratio in the cylinder 11 stoichiometric. Therefore, even if the F/C condition is satisfied, unburned fuel is discharged from the target cylinder into the exhaust passage 24 together with the exhaust gas.

In the next step S23, it is determined whether the firing process for the target cylinder has been executed for N cycles of the internal combustion engine 10 or not. That is, it is determined whether or not combustion is performed only in the target cylinder (for example, the first cylinder #1) for N consecutive cycles. "N" here is set to an integer greater than or equal to "1" (for example, 3).

In this embodiment, the control unit 61 varies the execution time of the firing process by adjusting "N", which is the number of cycles in which combustion is performed only in the target cylinder. That is, the controller 61 increases the execution time of the firing process by increasing "N" as the oil temperature TMP is lower and the oil viscosity is higher.

If it is not determined in step S23 that the firing process for the target cylinder has been executed for N cycles (NO), the process proceeds to step S22.

On the other hand, if it is determined in step S23 that the firing process for the target cylinder has been executed for N cycles (YES), the process proceeds to the next step S24. At step S24, it is determined whether or not the execution of the firing process has been completed for all cylinders 11 since this process routine was started. That is, after N consecutive cycles of combustion only in the cylinder 11 (for example, in the third cylinder #3) last selected as the target cylinder, the determination result in step S24 becomes "YES". . If there are still cylinders 11 that have not undergone combustion due to execution of the firing process (S24: NO), the process proceeds to step S21 described above. As a result, the target cylinder is changed. Then, in step S21, the target cylinder is changed. For example, after N consecutive cycles of combustion occurring only in the first cylinder #1, among the cylinders 11, a cylinder other than the first cylinder #1, for example the second cylinder #2, is selected as the target cylinder. . Further, for example, after N consecutive cycles of combustion occurring only in the second cylinder #2, among the cylinders 11, cylinders other than the first cylinder #1 and the second cylinder #2, for example, the third cylinder #2 3 is selected as the target cylinder.

On the other hand, if there is no cylinder 11 in which combustion has not been performed by execution of the firing process (S24: YES), the process proceeds to the next step S25. In step S25, the firing flag FLG is set to OFF. This is because it can be determined that the possibility of an event in which oil flows into the combustion chamber 13 through each ring groove 40 has decreased in all the cylinders 11 . Subsequently, in the next step S26, the duration time TM1 updated by the condition establishment determining section 62 is reset to "0". After that, this processing routine ends.

Note that when the firing process is executed for the target cylinder, the pressure in the combustion chamber 13 in the target cylinder increases due to combustion during the expansion stroke of the target cylinder. Therefore, when the piston 12 is moving toward the bottom dead center as indicated by the white arrow in FIG. be. As a result, as the piston 12 moves toward the bottom dead center during the expansion stroke, it is possible to prevent oil from entering the ring groove 40 and to scrape off the oil by the piston ring 30 . The oil thus scraped off flows down along the inner peripheral surface 111 of the cylinder 11 as indicated by the solid line arrow in FIG.

Next, with reference to FIG. 10, the operation and effects of this embodiment will be described. Here, it is assumed that the internal combustion engine 10 has three cylinders 11 .
The accelerator opening AC becomes "0" at timing t11 while the vehicle is running. At timing t11, the F/C condition is satisfied because the engine speed NE is higher than the determination speed NETh. Then, combustion is stopped in all cylinders 11 (#1, #2, #3) by executing the F/C process. When the F/C process is executed in this manner, the intake pipe negative pressure NPmc increases. Then, at timing t12, the intake pipe negative pressure NPmc becomes equal to or higher than the determination negative pressure NPth. That is, after timing t12, the F/C process is being executed and the intake pipe negative pressure NPmc continues to be equal to or higher than the determination negative pressure NPTh. Then, the update of the duration TM1 of the state is started from timing t12.

As the duration time TM1 is updated, the duration time TM1 reaches the determined negative pressure duration time TMTh1 at timing t13, so the firing flag FLG is set to ON. Then, the F/C process is temporarily interrupted and the firing process is executed. In this embodiment, the firing process is executed by selecting the target cylinder. That is, the fact that the firing flag FLG is turned on by the condition establishment determination unit 62 means that the duration time TM1 has reached the determination negative pressure duration time TMTh1. In the present embodiment, when the duration time TM1 reaches the determined negative pressure duration time TMTh1, the control unit 61 temporarily suspends the F/C process and executes the firing process. Therefore, in the present embodiment, the control unit 61 temporarily suspends the F/C process and executes the firing process on condition that the duration time TM1 reaches the determined negative pressure duration time TMTh1. can.

After timing t13, the first cylinder #1 is first selected as the target cylinder, and filing processing is performed on the first cylinder #1. Then, during N cycles (three cycles in the example shown in FIG. 10) of the internal combustion engine 10, combustion is performed in the first cylinder #1 while combustion is performed in the second cylinder #2 other than the first cylinder #1 and in the second cylinder #2. The state in which combustion is stopped in the third cylinder #3 continues. It should be noted that during the period in which the F/C process is temporarily interrupted and the firing process for the first cylinder #1 is repeatedly executed, the update of the duration time TM1 is stopped.

When combustion is performed in the first cylinder #1 in this way, the pressure in the combustion chamber 13 in the first cylinder #1 increases due to the combustion. With the ring 30 in contact with the wall surface 43 of the ring groove 40 on the crankcase 16 side, the piston 12 moves toward the bottom dead center. As a result, as the piston 12 moves toward the bottom dead center during the expansion stroke, it is possible to prevent oil from entering the ring groove 40 and to scrape off the oil by the piston ring 30 . By scraping off the oil in this way, it becomes difficult for the oil to flow into the combustion chamber 13 of the first cylinder #1 after the F/C process is restarted.

When the state in which combustion is performed only in the first cylinder #1 continues for N cycles, the target cylinder is changed from the first cylinder #1 to the second cylinder #2 as shown in FIG. Then, the firing process is executed for the second cylinder #2. In this embodiment, during N cycles, combustion is performed in the second cylinder #2, while combustion is stopped in the first cylinder #1 and the third cylinder #3 other than the second cylinder #2. is continued. It should be noted that during the period in which the F/C process is temporarily interrupted and the firing process for the second cylinder #2 is repeatedly executed, the update of the duration time TM1 is stopped.

When combustion is performed in the second cylinder #2 in this way, the pressure in the combustion chamber 13 in the second cylinder #2 increases due to the combustion, so that the combustion is performed in the first cylinder #1. 2, after the F/C process is restarted, it becomes difficult for oil to flow into the combustion chamber 13 in the second cylinder #2.

When the state in which combustion is performed only in the second cylinder #2 continues for N cycles, the target cylinder is changed from the second cylinder #2 to the third cylinder #3. Then, the firing process is executed for the third cylinder #3. In this embodiment, during N cycles, combustion is performed in the third cylinder #3, while combustion is stopped in the first cylinder #1 and the second cylinder #2 other than the third cylinder #3. is continued. It should be noted that during the period in which the F/C process is temporarily interrupted and the firing process for the third cylinder #3 is repeatedly executed, the update of the duration time TM1 is stopped.

When combustion is performed in the third cylinder #3 in this manner, the pressure in the combustion chamber 13 in the third cylinder #3 increases due to the combustion, so that the combustion is performed in the first cylinder #1. 2, after the F/C process is restarted, it becomes difficult for oil to flow into the combustion chamber 13 in the third cylinder #3.

When the state in which combustion is performed only in the third cylinder #3 continues for N cycles, the firing flag FLG is set to OFF and the duration TM1 is reset to "0" (timing t14). Since the F/C condition remains satisfied, the firing process is no longer performed after timing t14, and the F/C process is resumed. After timing t14, the duration TM1 is updated.

That is, in the present embodiment, even if the F/C condition continues to be satisfied for a long period of time, the F/C process is temporarily interrupted and the firing process is executed when the duration time TM1 becomes equal to or longer than the determined negative pressure duration time TMTh1. be done. Therefore, even if the F/C condition continues to be satisfied for a long period of time, it is possible to prevent oil from flowing into the combustion chamber 13 in each cylinder 11 from the crankcase 16 side.

In the example shown in FIG. 10, the accelerator operation is started at timing t15 during execution of the F/C process. Then, since the F/C condition is not satisfied, the F/C process is terminated. Also, the duration TM1 is reset to "0".

In this embodiment, the following effects can be obtained.
In the F/C process, the intake air is directly discharged from the combustion chamber 13 to the exhaust passage 24 and passes through the catalytic converter 25 . Therefore, the temperature of the catalytic converter 25 is more likely to drop than when the F/C process is not performed. In this embodiment, in the firing process, the fuel injection valve 21 injects an amount of fuel larger than the stoichiometric injection amount. Therefore, when the firing process is executed, unburned fuel is supplied to the catalytic converter 25 even if the F/C condition is satisfied. Then, the oxygen stored in the catalytic converter 25 reacts with the unburned fuel, so that the reaction can raise the temperature of the catalytic converter 25 . That is, it is possible to suppress the temperature drop of the catalytic converter 25 while the F/C condition is satisfied.

Also, the lower the oil temperature TMP and the higher the viscosity of the oil, the easier it is for the oil to flow into the combustion chamber 13 through the ring grooves 40. The execution frequency of ring processing is increased. In this way, by varying the execution frequency of the firing process according to the likelihood of occurrence of the event, when the F/C condition continues to be satisfied for a long period of time, oil will flow from the crankcase 16 into the cylinders 11. The effect of suppressing the flow into the combustion chamber 13 can be enhanced.

In other words, in the present embodiment, the higher the oil temperature TMP and the lower the viscosity of the oil, the less likely the above phenomenon will occur, so the frequency of execution of the firing process is reduced. As a result, unnecessary execution of the firing process can be suppressed, and fuel consumption of the internal combustion engine 10 can be suppressed.

(Second embodiment)
Next, a second embodiment of a vehicle-mounted internal combustion engine control apparatus will be described with reference to FIGS. 11 and 12. FIG. The second embodiment differs from the first embodiment in the content of determination as to whether or not the condition for permitting execution of the firing process has been established. Therefore, in the following description, the parts that are different from the first embodiment will be mainly described, and the same reference numerals will be given to the same or corresponding member configurations as in the first embodiment, and redundant description will be omitted. shall be

11 and 12, a processing routine executed by the condition establishment determining section 62 of the control device 60 while the vehicle is running will be described. This processing routine is repeatedly executed while the vehicle is running when the firing flag FLG is set to OFF.

As shown in FIG. 11, in the first step S31 of this processing routine, it is determined whether or not the F/C condition is satisfied, as in step S11. If it is not determined that the F/C condition is satisfied (S31: NO), the process proceeds to step S34. On the other hand, if it is determined that the F/C condition is established (S31: YES), the process proceeds to the next step S33.

In step S33, the duration TM2 of the state in which the F/C condition is satisfied is updated. The longer the duration of the F/C process, the more likely it is that oil pumped up by repeated reciprocating motions of the piston rings 30 in the ring grooves 40 will flow into the combustion chamber 13 . Therefore, in the present embodiment, regardless of whether the intake pipe negative pressure NPmc is equal to or higher than the determination negative pressure NPTh, updating of the duration time TM2 is started when the F/C condition is satisfied. Then, the process proceeds to step S35, which will be described later.

At step S34, the duration TM2 is reset to "0". After that, this processing routine is temporarily terminated.
In step S35, it is determined whether or not the updated duration TM2 is greater than or equal to the determination duration TMTh2. The phenomenon in which oil flows into the combustion chamber 13 through each ring groove 40 is more likely to occur as the duration TM2 is longer. Therefore, the determination continuation time TMTh2 is set as a criterion for determining whether or not there is a possibility that an event in which oil flows into the combustion chamber 13 through each ring groove 40 will occur. Therefore, when the duration time TM2 is equal to or longer than the determination duration time TMTh2, it can be determined that there is a possibility that oil flows into the combustion chamber 13 through the ring grooves 40 .

In the present embodiment, the determination continuation time TMTh2 is adjusted by the frequency adjuster 63. FIG. That is, as described above, the lower the oil temperature TMP and the higher the viscosity of the oil, the easier it is for the oil to flow into the combustion chamber 13 through the ring grooves 40 . Therefore, the frequency adjustment unit 63 sets the determination continuation time TMTh2 such that the lower the oil temperature TMP, the shorter the determination continuation time TMTh2. For example, the frequency adjustment unit 63 sets the determination duration time TMTh2 using the map shown in FIG.

The map shown in FIG. 12 is a map showing the relationship between the oil temperature TMP and the determination continuation time TMTh2. In this map, the higher the oil temperature TMP, the longer the determination continuation time TMTh2.
Returning to FIG. 11, in step S35, if the duration time TM2 is equal to or longer than the determination duration time TMTh2 (YES), the process proceeds to the next step S36. In this embodiment, if the determination in step S35 is "YES", it can be determined that the conditions for permitting execution of the firing process have been met. Therefore, in step S36, the firing flag FLG is set to ON. Then, this processing routine ends. In this case, the execution of this processing routine is suspended until the firing processing is executed and the firing flag FLG is set to OFF. On the other hand, if the duration time TM2 is less than the determination duration time TMTh2 (S35: NO), this processing routine is temporarily terminated without performing the processing of step S36. That is, in this case, the firing flag FLG remains off.

In this embodiment, when the firing flag FLG is set to ON, a processing routine equivalent to the processing routine shown in FIG. 8 is executed. That is, the control unit 61 temporarily suspends the F/C process and executes the firing process. The fact that the firing flag FLG is turned on by the condition establishment determination unit 62 means that the duration time TM2 has reached the determination duration time TMTh2. Then, in the present embodiment, when the duration time TM2 reaches the determination duration time TMTh2, the control unit 61 temporarily suspends the F/C process and executes the firing process. Therefore, in the present embodiment, it can be said that the control unit 61 temporarily suspends the F/C process and executes the firing process on condition that the duration time TM2 reaches the determination duration time TMTh2. Then, when combustion is performed in any cylinder 11 (S24: YES), the control unit 61 sets the firing flag FLG to OFF (S25) and resets the duration time TM2 to "0". . Therefore, in this embodiment, the same effects as those of the first embodiment can be obtained.

Note that the update of the duration time TM2 tends to start earlier than the update of the duration time TM1 in the first embodiment. Therefore, the determination continuation time TMTh2 may be set to a value larger than the determination negative pressure continuation time TMTh1.

(Third embodiment)
Next, a third embodiment of a vehicle internal combustion engine control device will be described with reference to FIG. In the third embodiment, the details of the firing process are different from those in the first and second embodiments. Therefore, in the following description, the parts that are different from the second embodiment will be mainly described, and the same reference numerals will be given to the same or corresponding member configurations as in the second embodiment, and redundant description will be omitted. shall be

The firing process executed in this embodiment is a process of causing combustion in all cylinders 11 during N cycles of the internal combustion engine 10 .
With reference to FIG. 13, the operation of the present embodiment and the differences from the second embodiment will be described, and the effects thereof will be described.

The accelerator opening AC becomes "0" at timing t31 while the vehicle is running. At timing t31, the F/C condition is satisfied because the engine speed NE is higher than the determination speed NETh. Then, combustion is stopped in all the cylinders 11 by executing the F/C process. Then, when the F/C condition is satisfied, updating of the duration time TM2 is started. Since the duration time TM2 reaches the determination duration time TMTh2 at timing t32, the firing flag FLG is turned on. Then, the F/C process is temporarily interrupted and the firing process is executed.

In the firing process, combustion is performed in any cylinder 11 . When combustion is performed in each cylinder 11 in this way, the pressure in the combustion chamber 13 in each cylinder 11 increases due to the combustion. , the piston 12 moves toward the bottom dead center while in contact with the wall surface 43 of . As a result, as the piston 12 moves toward the bottom dead center during the expansion stroke, it is possible to prevent oil from entering the ring groove 40 and to scrape off the oil by the piston ring 30 . By scraping off the oil in this way, it becomes difficult for the oil to flow into the combustion chamber 13 in each cylinder 11 after the F/C process is restarted. Therefore, it is possible to prevent oil from flowing into the combustion chamber 13 in each cylinder 11 through each ring groove 40 during execution of the F/C process.

When the firing process ends at timing t33, the F/C condition remains satisfied, so the F/C process is restarted and the duration time TM2 is reset to "0". Since the engine rotation speed NE reaches the determination rotation speed NETh at timing t34 during execution of the F/C process, the F/C condition is not satisfied. This completes the F/C process.

In this embodiment, the following effects can be further obtained.
In the firing process executed in the first embodiment and the second embodiment, combustion is performed in only one cylinder 11 in one cycle of the internal combustion engine 10 . Therefore, a relatively long time is required from when the firing flag FLG is set to ON to when the firing flag FLG is set to OFF. In contrast, in the firing process executed in the present embodiment, combustion is performed in any cylinder 11 in one cycle of the internal combustion engine 10 . Therefore, the time required from when the firing flag FLG is set to ON to when the firing flag FLG is set to OFF can be made shorter than in the first and second embodiments.

(Change example)
Each of the above embodiments can be implemented with the following modifications. Each of the above-described embodiments and the following modifications can be implemented in combination with each other within a technically consistent range.

When injecting fuel from the fuel injection valve 21 by firing process, if combustion can be performed in the cylinder 11, the fuel injection amount of the fuel injection valve 21 should not be larger than the stoichiometric injection amount. may For example, the fuel injection amount of the fuel injection valve 21 may be the stoichiometric injection amount or may be smaller than the stoichiometric injection amount.

- In the third embodiment, the execution period of the firing process is N cycles of the internal combustion engine 10 . However, the firing process may be a process in which combustion is performed in each cylinder 11 during one cycle in the internal combustion engine 10 and then terminated. In this case, the number of times combustion is performed in each cylinder 11 in the firing process is reduced. Therefore, while the firing flag FLG is set to ON, the firing process may be divided into N times. That is, it is not necessary to continuously execute the firing process. Of course, the number of times the firing process is performed while the firing flag FLG is set to ON is not limited to N times, and may be set to any number of times.

- In each of the above embodiments, the execution frequency of the firing process is varied according to the oil temperature TMP, but the execution frequency of the firing process may not be varied according to the oil temperature TMP. In this case, the determination continuation time TMTh2 and the determination negative pressure continuation time TMTh1 are fixed at preset lengths.

- It can be inferred that the higher the temperature of the cooling water circulating in the internal combustion engine 10, the higher the oil temperature TMP, that is, the lower the viscosity of the oil. Therefore, the coolant temperature may be used as the correlation value of the oil temperature TMP. In this case, it is desirable to increase the execution frequency of the firing process as the cooling water temperature decreases.

The execution time of the firing process may be varied according to the cooling water temperature, which is a correlation value of the oil temperature TMP. For example, the lower the cooling water temperature, the longer the execution time of the firing process.

- It is not necessary to change the execution time of the firing process according to the oil temperature TMP.
The inventors of the present application have found that the higher the engine rotation speed NE is during the execution of the F/C process, the more difficult it is for the oil to flow into the combustion chamber 13 through the ring grooves 40. It has gained. Therefore, for example, the lower the engine rotation speed NE at the time when the F/C condition is satisfied, the smaller the determination continuation time TMTh2 and the determination negative pressure continuation time TMTh1 may be made.

- In each of the above embodiments, combustion is performed in all cylinders 11 while the firing flag FLG is set to ON. However, some of the cylinders 11 of the internal combustion engine 10 may be caused to burn in the combustion chamber 13 by executing the filing process while the firing flag FLG is set to ON.

- The fuel injection valve 21 may be a port injection valve that injects fuel into the intake passage 18 . Further, the internal combustion engine to be controlled by the control device 60 may have both a port injection valve and an in-cylinder injection valve.

The internal combustion engine to be controlled by the control device 60 may be a compression ignition internal combustion engine instead of a spark ignition internal combustion engine.

DESCRIPTION OF SYMBOLS 10... Internal combustion engine, 11... Cylinder, 18... Intake passage, 19... Throttle valve, 21... Fuel injection valve, 60... Control device, 61... Control part, 63... Frequency adjustment part.

Claims (8)

A control device for an on-vehicle internal combustion engine having a control unit that executes a fuel cut process that suspends combustion in all cylinders when a prescribed fuel cut condition is satisfied during deceleration of the vehicle,
The control unit temporarily suspends the fuel cut process and executes a firing process in which fuel is injected from a fuel injection valve to cause combustion in the cylinder. Temporarily interrupting the process to increase the frequency of executing the firing process
A control device for an internal combustion engine in a vehicle. A control device for an on-vehicle internal combustion engine having a control unit that executes a fuel cut process that suspends combustion in all cylinders when a prescribed fuel cut condition is satisfied during deceleration of the vehicle,
On the condition that the duration time of the fuel cut processing reaches the determination duration time, the control unit temporarily suspends the fuel cut processing and injects fuel from the fuel injection valve to cause combustion in the cylinder. Execute the firing process that causes the
A frequency adjustment unit that shortens the determination continuation time as the oil temperature or the correlation value of the oil temperature is lower
A control device for an internal combustion engine in a vehicle. A control device for an on-vehicle internal combustion engine having a control unit that executes a fuel cut process that suspends combustion in all cylinders when a prescribed fuel cut condition is satisfied during deceleration of the vehicle,
During the execution of the fuel cut process, the control unit operates on the condition that the duration of a state in which the negative pressure on the downstream side of the throttle valve in the intake passage is equal to or higher than the determination negative pressure reaches the determination negative pressure continuation time. and executing a firing process in which the fuel cut process is temporarily interrupted and fuel is injected from the fuel injection valve to cause combustion in the cylinder.
A control device for an internal combustion engine in a vehicle. 4. The control device for a vehicle-mounted internal combustion engine according to claim 3 , further comprising a frequency adjusting unit that shortens the determination negative pressure duration time as the oil temperature or the correlation value of the oil temperature is lower. A control device for an on-vehicle internal combustion engine having a control unit that executes a fuel cut process that suspends combustion in all cylinders when a prescribed fuel cut condition is satisfied during deceleration of the vehicle,
The control unit executes a firing process for causing combustion in the cylinder by temporarily interrupting the fuel cut process and injecting fuel from a fuel injection valve,
The lower the oil temperature, the longer the execution time of the firing process.
A control device for an internal combustion engine in a vehicle. When one of all the cylinders is the target cylinder,
The firing process for performing combustion only in the cylinder selected as the target cylinder during one cycle of the in-vehicle internal combustion engine during the period in which the fuel cut process is temporarily suspended is performed on the target cylinder. sequentially for all the cylinders while changing
A control device for a vehicle-mounted internal combustion engine according to any one of claims 1 to 5. 6. The vehicle internal combustion engine according to any one of claims 1 to 5 , wherein the firing process is a process in which combustion is performed in each of the cylinders during one cycle in the vehicle internal combustion engine, and the process ends. Control device. In the firing process, the control unit causes the fuel injection valve to inject an amount of fuel larger than a stoichiometric injection amount, which is a fuel injection amount that makes an air - fuel ratio stoichiometric. 1. A control device for a vehicle-mounted internal combustion engine according to claim 1.

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