JP2023048428A - Control device for internal combustion engine - Google Patents

Abstract

To increase the accuracy in estimating the temperature of a gas discharged from cylinders, to which fuel supply is stopped, among a plurality of cylinders.SOLUTION: A CPU 72 executes: specific cylinder stop processing of stopping fuel supply to some cylinders among a plurality of cylinders and performing fuel supply to the remaining cylinders other than the some cylinders; all cylinder stop processing of stopping fuel supply to all the cylinders; and temperature calculation processing of calculating a gas temperature, which is the temperature of a gas discharged from the cylinders of the internal combustion engine 10 into an exhaust passage 30. The temperature calculation processing includes processing of calculating the gas temperature on the basis of a temperature of the exhaust passage during execution of the all cylinder stop processing, and processing of calculating the gas temperature of the stopped cylinders, to which fuel supply is stopped, on the basis of a flow rate of the gas discharged from the stopped cylinders and an engine water temperature, during execution of the specific cylinder stop processing.SELECTED DRAWING: Figure 1

Description

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

For example, in Patent Document 1, the temperature of the exhaust passage is substituted as the gas temperature, which is the temperature of the gas discharged from the internal combustion engine to the exhaust passage, during the so-called fuel cut, in which the fuel supply to all cylinders is stopped. A device is described.

On the other hand, Japanese Patent Laid-Open No. 2002-200000 discloses a specific cylinder stop system in which fuel supply to some cylinders out of a plurality of cylinders of an internal combustion engine is stopped and fuel supply to the remaining cylinders other than some of the cylinders is performed. An apparatus for performing the process is described.

JP 2020-56325 A Japanese Patent Application Laid-Open No. 2021-60027

By the way, when executing the specific cylinder stop process, air is discharged as gas from the stopped cylinder to which the fuel supply is stopped, in the same manner as during execution of the above-described fuel cut. Combustion gas is discharged from the combustion cylinder in which the air-fuel mixture is combusted by the fuel supply.

Here, when executing the specific cylinder stop process, the temperature of the exhaust passage increases due to the combustion gas discharged from the combustion cylinder. Therefore, if the temperature of the exhaust passage is used as the temperature of the gas discharged from the stopped cylinder, the calculated gas temperature will be higher than the actual gas temperature, and the estimation accuracy of the temperature of the gas discharged from the stopped cylinder will increase. may decrease.

A control device for an internal combustion engine that solves the above problems is applied to an internal combustion engine having a plurality of cylinders. The control device includes a specific cylinder stop process of stopping fuel supply to some of the plurality of cylinders and performing fuel supply to the remaining cylinders other than the certain cylinders; and a temperature calculation process for calculating the gas temperature, which is the temperature of the gas discharged from the cylinders of the internal combustion engine to the exhaust passage. The temperature calculation process includes a process of calculating the gas temperature based on the temperature of the exhaust passage during execution of the all-cylinder stop process, and a process of calculating the gas temperature based on the temperature of the exhaust passage during execution of the specific cylinder stop process. calculating the gas temperature of the stopped cylinder based on the flow rate of gas discharged from the stopped cylinder and the engine water temperature.

The gas discharged from the stopped cylinder whose fuel supply is stopped by executing the specific cylinder stop process receives heat from the wall surface when passing through the combustion chamber of the stopped cylinder. The wall surface temperature of the combustion chamber of the stopped cylinder depends on the engine water temperature. Further, the time during which the gas passing through the combustion chamber of the stopped cylinder receives heat from the wall surface of the combustion chamber depends on the flow rate of the gas discharged from the stopped cylinder to the exhaust passage. Therefore, the temperature of the gas discharged from the combustion chamber of the stopped cylinder can be estimated based on the engine water temperature and the gas flow rate.

Therefore, in this configuration, during execution of the specific cylinder stop process, the gas temperature of the stopped cylinder is calculated based on the flow rate of the gas discharged from the stopped cylinder into the exhaust passage and the engine water temperature. Therefore, it is possible to improve the accuracy of estimating the temperature of the gas discharged from the stopped cylinder.

1 is a diagram showing configurations of an internal combustion engine, a drive system, and a control device according to one embodiment; FIG. It is a flowchart which shows the processing procedure which the control apparatus of the same embodiment performs. It is a flowchart which shows the processing procedure which the control apparatus of the same embodiment performs.

<Configuration of Internal Combustion Engine, Drive System, and Control Device>
An embodiment of a control device for an internal combustion engine will be described below with reference to the drawings.
As shown in FIG. 1, the internal combustion engine 10 has four cylinders, for example cylinder #1 to cylinder #4.

A throttle valve 14 is provided in an intake passage 12 of the internal combustion engine 10 .
An intake port 12a, which is a downstream portion of the intake passage 12, is provided with a port injection valve 16 for injecting fuel into the intake port 12a. Air taken into the intake passage 12 and fuel injected from the port injection valve 16 flow into the combustion chamber 20 as the intake valve 18 opens.

A cylinder head of the internal combustion engine 10 is provided with an in-cylinder injection valve 22 that injects fuel directly into the combustion chamber 20 .
The air-fuel mixture in the combustion chamber 20 is combusted by the spark discharge of the ignition plug 24 . The combustion energy generated at that time is converted into rotational energy of the crankshaft 26 .

The air-fuel mixture combusted in the combustion chamber 20 of each cylinder is discharged to the exhaust passage 30 as exhaust gas when the exhaust valve 28 is opened. The exhaust passage 30 is provided with a three-way catalyst 32 having an oxygen storage capacity and a gasoline particulate filter (GPF 34) that collects particulate matter (hereinafter referred to as PM) in the exhaust. In this embodiment, it is assumed that the GPF 34 is a filter that collects PM and supports a three-way catalyst.

The crankshaft 26 is mechanically connected to a carrier C of a planetary gear mechanism 50 that constitutes a power split device. The sun gear S of the planetary gear mechanism 50 is mechanically connected to the rotating shaft 52 a of the first motor generator 52 . Further, the ring gear R of the planetary gear mechanism 50 is mechanically connected to the rotating shaft 54 a of the second motor generator 54 and the drive wheel 60 . An AC voltage is applied to terminals of the first motor generator 52 by an inverter 56 . An AC voltage is applied to terminals of the second motor generator 54 by an inverter 58 .

The control device 70 controls the internal combustion engine 10, and controls the throttle valve 14, the port injection valve 16, the in-cylinder injection valve 22, the spark plug 24, etc. in order to control the torque, the exhaust gas component ratio, etc. as the control amount. , various operation units of the internal combustion engine 10 are operated. Further, the control device 70 controls the first motor generator 52 and operates the inverter 56 so as to control the rotation speed, which is the control amount thereof. Further, the control device 70 controls the second motor generator 54 and operates the inverter 58 to control the torque, which is the control amount of the second motor generator 54 . FIG. 1 shows operation signals MS1 to MS6 for the throttle valve 14, the port injection valve 16, the in-cylinder injection valve 22, the spark plug 24, and the inverters 56, 58, respectively.

In order to control the control amount of the internal combustion engine 10, the control device 70 controls the intake air amount Ga detected by the air flow meter 80, the output signal Scr of the crank angle sensor 82, and the cooling of the internal combustion engine 10 detected by the water temperature sensor 86. Refers to water temperature (engine water temperature THW). The control device 70 also refers to the intake air temperature THA detected by the intake air temperature sensor 84 . Here, the intake air temperature THA is referred to as the outside air temperature. The control device 70 also refers to the pressure Pex of the exhaust flowing into the GPF 34, which is the value detected by the exhaust pressure sensor 88. The control device 70 also refers to the air-fuel ratio Af detected by the air-fuel ratio sensor 89 on the upstream side of the three-way catalyst 32 . In addition, in order to control the amount of control of the first motor generator 52 and the second motor generator 54, the control device 70 outputs an output signal Sm1 of the first rotation angle sensor 90 that detects the rotation angle of the first motor generator 52, and The output signal Sm2 of the second rotation angle sensor 92 that detects the rotation angle of the second motor generator 54 is referred to.

The control device 70 includes a CPU 72 , a ROM 74 , a storage device 75 , and a peripheral circuit 76 , which can communicate with each other through a communication line 78 . Here, the peripheral circuit 76 includes a circuit that generates a clock signal that defines internal operations, a power supply circuit, a reset circuit, and the like. The control device 70 controls the control amount by causing the CPU 72 to execute programs stored in the ROM 74 .

<Processing executed by the control device>
Control device 70 calculates engine speed NE based on output signal Scr. The control device 70 also calculates the engine load factor KL. The engine load factor KL is a parameter that determines the amount of air charged into the combustion chamber 20, and is the ratio of the inflow air amount per cylinder per combustion cycle to the reference inflow air amount. Note that the reference inflow air amount may be an amount that is variably set according to the engine speed NE.

<Regeneration processing>
FIG. 2 shows the procedure of processing executed by the control device 70 according to this embodiment. The processing shown in FIG. 2 is implemented by the CPU 72 repeatedly executing a program stored in the ROM 74 at predetermined intervals, for example. Note that, hereinafter, the step number of each process is represented by a number prefixed with “S”.

In the series of processes shown in FIG. 2, the CPU 72 first acquires the engine speed NE, the engine load factor KL, and the engine water temperature THW (S10).
Next, the CPU 72 calculates an update amount ΔDPM of the accumulated amount DPM based on the engine speed NE, the engine load factor KL, and the engine water temperature THW (S12). Here, the deposition amount DPM is the amount of PM trapped in the GPF 34 . Specifically, the CPU 72 calculates the amount of PM in the exhaust discharged to the exhaust passage 30 based on the engine speed NE, the engine load factor KL, and the engine water temperature THW. Also, the CPU 72 acquires the temperature of the GPF 34 calculated by another process. Then, the CPU 72 calculates the update amount ΔDPM based on the amount of PM in the exhaust gas and the temperature of the GPF 34 .

Next, the CPU 72 updates the deposition amount DPM according to the update amount ΔDPM (S14).
Next, the CPU 72 determines whether or not the flag F is "1" (S16). When the flag F is "1", it indicates that the temperature raising process for burning and removing the PM in the GPF 34 is being performed, and when it is "0", it indicates otherwise.

When determining that the flag F is "0" (S16: NO), the CPU 72 determines whether or not the accumulated amount DPM is equal to or greater than the regeneration execution value DPMH (S18). The regeneration execution value DPMH is set to a value at which the amount of PM collected by the GPF 34 is large and removal of PM is desired.

When the CPU 72 determines that the accumulated amount DPM is equal to or greater than the regeneration execution value DPMH (S18: YES), it determines whether or not conditions for executing the temperature raising process are satisfied (S20). Here, the execution condition may be, for example, a condition that the logical AND of the following condition (A) and condition (B) is true.

Condition (A): A condition that the engine torque command value Te*, which is a torque command value for the internal combustion engine 10, is equal to or greater than a predetermined value Teth.
Condition (B): A condition that the engine speed NE of the internal combustion engine 10 is equal to or higher than a predetermined speed.

When the CPU 72 determines that the conditions for executing the temperature increase process are satisfied (S20: YES), the CPU 72 executes the temperature increase process and substitutes "1" for the flag F (S22). As this temperature raising process, the CPU 72 executes a specific cylinder stop process.

This specific cylinder stop process is a process of stopping the fuel supply to some of the plurality of cylinders and performing the fuel supply to the remaining cylinders other than the certain cylinders. and bulking.

The stop processing is processing to stop fuel injection from the port injection valve 16 and the in-cylinder injection valve 22 of cylinder #1, that is, to stop fuel supply to cylinder #1 by executing a fuel cut. The cylinders for which this stop process is performed are hereinafter referred to as stopped cylinders, and the remaining cylinders other than the stopped cylinders, that is, the cylinders to which fuel is supplied and the air-fuel mixture is combusted are referred to as combustion cylinders.

In the increase processing, in order to supply unburned fuel to the exhaust passage 30, the amount of fuel supplied to each combustion cylinder of cylinder #2, cylinder #3, and cylinder #4 is increased more than when the stop processing is not executed. It is a process to During execution of this increase processing, the amount of fuel injected from the port injection valve 16 or the in-cylinder injection valve 22 is increased so that the air-fuel ratio of the air-fuel mixture in the combustion cylinder becomes richer than the stoichiometric air-fuel ratio.

This specific cylinder stop process supplies oxygen and unburned fuel to the exhaust passage 30 to increase the temperature of the GPF 34 , thereby performing a regeneration process for burning and removing PM trapped in the GPF 34 . That is, by discharging oxygen and unburned fuel into the exhaust passage 30, the temperature of the GPF 34 is raised by burning the unburned fuel in the three-way catalyst 32 or the like and raising the temperature of the exhaust gas. By supplying oxygen to the GPF 34, the PM collected by the GPF 34 is burned and removed.

In addition, the CPU 72 executes MG2 torque compensation processing in order to compensate for the decrease in engine output that accompanies execution of the stop processing (S24). In this MG2 torque compensation process, the CPU 72 superimposes the compensation torque, which is the output torque for one cylinder, on the required torque for running of the second motor generator 54 . Then, the CPU 72 operates the inverter 58 based on the required torque on which the compensating torque is superimposed.

On the other hand, in the process of S16, when the CPU 72 determines that the flag F is "1" (S16: YES), it determines whether or not the accumulated amount DPM is equal to or less than the stop threshold value DPML (S26). . The stopping threshold value DPML is set to a value at which the amount of PM trapped in the GPF 34 becomes sufficiently small and the temperature raising process can be stopped. When the CPU 72 determines that the accumulated amount DPM is equal to or less than the stop threshold value DPML (S26: YES), the CPU 72 stops the temperature raising process by stopping the partial cylinder fuel cut process, and sets the flag F to "0". is substituted (S28).

It should be noted that the CPU 72 once ends the series of processes shown in FIG. 2 when completing the processes of S24 and S28 or when making a negative determination in the processes of S18 and S20.
<Gas temperature calculation processing>
The control device 70 executes temperature calculation processing for calculating the gas temperature, which is the temperature of the gas discharged from the cylinder of the internal combustion engine 10 to the exhaust passage 30 .

FIG. 3 shows the procedure of temperature calculation processing executed by the control device 70 . The processing shown in FIG. 3 is implemented by the CPU 72 repeatedly executing a program stored in the ROM 74 at predetermined intervals, for example.

In the series of processes shown in FIG. 3, the CPU 72 first calculates a base output gas temperature Toutb, which is the base value of the output gas temperature Tout, which is the temperature of the gas discharged from the cylinder of the internal combustion engine 10 to the exhaust passage 30. (S100). In this embodiment, the operating point of the internal combustion engine 10 is defined by the engine load factor KL and the engine speed NE.

More specifically, the CPU 72 performs map calculation of the base output gas temperature Toutb in a state in which map data having the engine speed NE and the engine load factor KL as input variables and the base output gas temperature Toutb as output variables is stored in the ROM 74 in advance. be. Here, the base output gas temperature Toutb is, for example, that the air-fuel ratio is a predetermined air-fuel ratio (here, the stoichiometric air-fuel ratio is assumed), or that the ignition timing is a predetermined ignition timing (here, MBT). , that the engine coolant temperature THW is a predetermined temperature, and that the intake air temperature THA is a predetermined temperature.

Next, the CPU 72 determines that the logical sum of the fact that the all-cylinder fuel cut process is being executed as the all-cylinder stop process for stopping the fuel supply to all the cylinders and the fact that the internal combustion engine 10 is stopped is true. It is determined whether or not there is (S110).

Then, the CPU 72 determines that the mixture of the air flowing into the combustion chamber 20 through the intake passage 12 and the fuel injected from the port injection valve 16 or the in-cylinder injection valve 22 is combusted by the spark discharge of the ignition plug 24. If there is (S110: NO), the process proceeds to S120.

In the process of S120, the CPU 72 calculates the first outgas temperature Tout1 by adding the first correction amount ΔT1 and the second correction amount ΔT2 to the base outgas temperature Toutb. This first exit gas temperature Tout1 is the temperature of the gas discharged from the combustion cylinder.

The first correction amount ΔT1 is calculated by the CPU 72 based on the engine water temperature THW, the air-fuel ratio Af, the ignition timing aig, and the intake air temperature THA. The first correction amount ΔT1 is a correction amount for correcting the base output gas temperature Toutb based on the deviation of the actual state from the conditions assumed when calculating the base output gas temperature Toutb. That is, for example, when the actual air-fuel ratio Af deviates from the assumed air-fuel ratio, it becomes a correction amount for decreasing the base output gas temperature Toutb. Further, for example, when the actual ignition timing aig deviates to the retarded side with respect to the assumed ignition timing, it becomes a correction amount for increasing the base output gas temperature Toutb.

On the other hand, the second correction amount ΔT2 is calculated by the CPU 72 based on the ignition timing aig, the intake air amount Ga, and the air-fuel ratio Af. The second correction amount .DELTA.T2 is the amount of temperature rise of the exhaust gas caused by combustion of unburned fuel and oxygen when they are present in the exhaust gas discharged from the combustion chamber 20. FIG. The more the ignition timing aig is retarded with respect to the MBT, the more the unburned fuel and oxygen are present in the exhaust gas discharged from the combustion chamber 20. calculate.

Next, the CPU 72 determines whether or not specific cylinder stop processing is being executed (S130). When the CPU 72 determines that the specific cylinder stop process is being executed (S130: YES), the CPU 72 calculates the second output gas temperature Tout2 (S140). This second exit gas temperature Tout2 is the temperature of the gas discharged from the stopped cylinder.

Specifically, the second output gas temperature Tout2 is map-calculated by the CPU 72 in a state in which the map data having the engine water temperature THW and the gas flow rate Ge as input variables and the second output gas temperature Tout2 as output variables is stored in the ROM 74 in advance. be. The gas flow rate Ge used as an input variable in S140 is the flow rate of gas discharged from the stopped cylinder into the exhaust passage 30, and is a value calculated by the CPU 72 based on the intake air amount Ga, the engine rotation speed NE, and the like. . Incidentally, the gas flow rate Ge may be directly detected by a flow rate sensor or the like. Then, the higher the engine water temperature THW, the higher the CPU 72 calculates the second output gas temperature Tout2 to be a larger value (higher temperature). Further, the CPU 72 calculates the second output gas temperature Tout2 to be a larger value (higher temperature) as the gas flow rate Ge is smaller. The process of S140 corresponds to the process of calculating the gas temperature of the stopped cylinder based on the engine water temperature and the flow rate of the gas discharged from the stopped cylinder to which fuel supply is stopped during execution of the specific cylinder stop process. .

Next, the CPU 72 calculates the output gas temperature Tout based on the first output gas temperature Tout1 and the second output gas temperature Tout2 (S150). Specifically, the CPU 72 substitutes the sum of the value obtained by multiplying the first output gas temperature Tout1 by the coefficient K4 and the value obtained by multiplying the second output gas temperature Tout2 by the coefficient K5 into the output gas temperature Tout. Coefficient K4 and coefficient K5 are the following values. That is, when the number of cylinders to be stopped in one combustion cycle when the specific cylinder stop process is executed is N1, and the total number of cylinders of the internal combustion engine 10 is N, the coefficient K4 is "(N−N1)/ N” is the value indicated. Here, the value of (N-N1) is the number of cylinders that become combustion cylinders in one combustion cycle when the specific cylinder stop process is executed. Also, the coefficient K5 is a value indicated by "N1/N". For example, in this embodiment, the coefficient K4 is "(4-1)/4=0.75" and the coefficient K5 is "1/4=0.25".

When a negative determination is made in S130, the CPU 72 substitutes the first outgas temperature Tout1 calculated in S120 for the outgas temperature Tout (S160).
In the process of S110, when the CPU 72 determines that the logical sum is true (S110: YES), the CPU 72 substitutes the exhaust manifold temperature Texm in the previous control cycle of the process shown in FIG. 3 into the output gas temperature Tout (S170). . The exhaust manifold temperature Texm is the wall surface temperature of the exhaust passage 30 on the exhaust upstream side of the three-way catalyst 32 . In addition, in FIG. 3, in order to distinguish between the current value and the previous value in the series of processes shown in FIG. -1” is described. Further, the process of S170 corresponds to the process of calculating the gas temperature based on the temperature of the exhaust passage during execution of the all-cylinder stop process.

When any one of S150, S160, and S170 is completed, the CPU 72 determines whether the internal combustion engine 10 is stopped (S180). When determining that the engine is stopped (S180: YES), the CPU 72 calculates an update amount ΔTexm of the exhaust manifold temperature Texm based on the difference between the exhaust manifold temperature Texm and the engine water temperature THW (S200). Specifically, the higher the exhaust manifold temperature Texm is than the engine water temperature THW, the smaller the CPU 72 calculates the update amount ΔTexm. Specifically, the CPU 72 substitutes a value obtained by subtracting the exhaust manifold temperature Texm from the engine water temperature THW and multiplying the value by a predetermined coefficient K1 into the update amount ΔTexm.

On the other hand, in the process of S180, when the CPU 72 determines that it is not stopped (S180: NO), in addition to the difference between the engine water temperature THW and the exhaust manifold temperature Texm, the difference between the exhaust gas temperature Tout and the exhaust manifold temperature Texm Based on this, the update amount ΔTexm is calculated (S220). Specifically, the CPU 72 calculates the update amount ΔTexm to a larger value as the output gas temperature Tout is higher than the exhaust manifold temperature Texm. Specifically, the CPU 72 multiplies a value obtained by subtracting the exhaust manifold temperature Texm from the engine coolant temperature THW by a predetermined coefficient K1, and multiplies a value obtained by subtracting the exhaust manifold temperature Texm from the output gas temperature Tout by a predetermined coefficient K2. value is substituted for the update amount ΔTexm.

When the processes of S200 and S220 are completed, the CPU 72 updates the exhaust manifold temperature Texm by adding the update amount ΔTexm to the exhaust manifold temperature Texm (S240).
Next, the CPU 72 updates the incoming gas temperature Tin based on the difference between the exhaust manifold temperature Texm and the outgoing gas temperature Tout (S260). The inlet gas temperature Tin is the temperature of the gas flowing into the three-way catalyst 32 . Specifically, the CPU 72 calculates the decreasing correction amount to a larger value as the output gas temperature Tout is higher than the exhaust manifold temperature Texm, and calculates the incoming gas temperature Tin by decreasing the output gas temperature Tout by the decreasing correction amount. do. Specifically, the CPU 72 calculates the incoming gas temperature Tin by adding to the outgoing gas temperature Tout a value obtained by subtracting the outgoing gas temperature Tout from the exhaust manifold temperature Texm and multiplying the result by a predetermined coefficient K3. Note that the CPU 72 does not calculate the incoming gas temperature Tin by the process of S260 when executing the process of S170, and sets the value calculated by the process of S170 as the current incoming gas temperature Tin.

Next, the CPU 72 calculates the temperature of the three-way catalyst 32 using the incoming gas temperature Tin (S280). Here, when the incoming gas temperature Tin is high, the temperature of the three-way catalyst 32 is calculated to be higher than when it is low. Specifically, for example, a value obtained by subtracting the temperature of the three-way catalyst 32 from the incoming gas temperature Tin and multiplying the value by a predetermined coefficient may be used as the correction amount for the temperature of the three-way catalyst 32 . However, the present invention is not limited to this, and for example, the three-way catalyst 32 may be divided into a plurality of regions from upstream to downstream, and the temperature of each region may be calculated in consideration of heat exchange between the regions. In that case, the temperature of the most upstream region may be calculated in consideration of heat exchange with the fluid having the incoming gas temperature Tin.

Then, when the process of S280 is completed, the CPU 72 once terminates the series of processes shown in FIG.
For example, the CPU 72 starts the internal combustion engine 10 when the temperature of the three-way catalyst 32 calculated by the process of S280 is equal to or lower than a specified temperature while the internal combustion engine 10 is stopped. By starting the internal combustion engine 10, the temperature of the three-way catalyst 32 is raised to the activation temperature to ensure exhaust purification performance.

<Action and effect>
The action and effect of this embodiment will be described.
(1) The gas discharged from the stopped cylinder whose fuel supply has been stopped by executing the specific cylinder stop process receives heat from the wall surface of the combustion chamber 20 of the stopped cylinder when passing through the combustion chamber 20 . The wall surface temperature of the combustion chamber 20 of the stopped cylinder is a value that depends on the engine water temperature THW. The time for the gas passing through the combustion chamber 20 of the stopped cylinder to receive heat from the wall surface of the combustion chamber 20 depends on the gas flow rate Ge of the gas discharged from the stopped cylinder to the exhaust passage 30 . Therefore, the temperature of the gas discharged from the combustion chamber 20 of the stopped cylinder to the exhaust passage 30 can be estimated based on the engine water temperature THW and the gas flow rate Ge.

Therefore, in this embodiment, the process of S140 shown in FIG. 3 is executed while the specific cylinder stop process is being executed. That is, the second output gas temperature Tout2, which is the gas temperature of the stopped cylinder, is calculated based on the gas flow rate Ge of the gas discharged from the stopped cylinder into the exhaust passage 30 and the engine water temperature THW. Therefore, it is possible to improve the accuracy of estimating the temperature of the gas discharged from the stopped cylinder.

(2) The exit gas temperature Tout of the gas discharged from the internal combustion engine 10 into the exhaust passage 30 during execution of the specific cylinder stop process is affected by the ratio between the number of stop cylinders and the number of combustion cylinders in one combustion cycle. . Therefore, in this embodiment, the process of S150 shown in FIG. 3 is executed while the specific cylinder stop process is being executed. That is, the output gas temperature Tout is calculated by weighting the first output gas temperature Tout1 and the second output gas temperature Tout2 with coefficients K4 and K5 that indicate the ratio between the number of stopped cylinders and the number of combustion cylinders. I have to. Therefore, it is possible to improve the estimation accuracy of the output gas temperature Tout during execution of the specific cylinder stop processing.

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 predetermined conditions for permitting execution of the above-described temperature raising process are not limited to those exemplified in the above-described embodiment. For example, with respect to the two conditions (A) and (B) above, only one of them may be included. Also, the predetermined conditions may include conditions other than the above two conditions.

- In order to compensate for the decrease in engine output that accompanies the execution of the above-described stop processing, in the processing of S24 shown in FIG. In addition, in the case of a vehicle that does not have such a second motor generator 54, the output torque of the combustion cylinder is increased by increasing the amount of air and the amount of fuel supplied to the combustion cylinder more than when the stop processing is not executed. A decrease in the engine output may be compensated for by increasing it.

- The process for executing the specific cylinder stop process is not limited to the regeneration process described above. For example, specific cylinder stop processing may be executed for catalyst warm-up and sulfur poisoning recovery. Further, for example, specific cylinder stop processing may be executed in order to increase the oxygen storage amount of the three-way catalyst 32 .

- The process of estimating the amount of deposition DPM is not limited to that illustrated in FIG. For example, the accumulation amount DPM may be estimated based on the difference in pressure between the upstream side and the downstream side of the GPF 34 and the intake air amount Ga. Specifically, when the pressure difference is large, the accumulation amount DPM is estimated to be a larger value than when the pressure difference is small. DPM should be estimated to a large value. Here, when the pressure on the downstream side of the GPF 34 can be considered to be a substantially constant value substantially equal to the atmospheric pressure, the pressure Pex can be used instead of the differential pressure.

・The number of stopped cylinders for which fuel supply is stopped in one combustion cycle when the specific cylinder stop process is executed was "1", but the maximum number of stopped cylinders is "the number of all cylinders - 1". can be changed as appropriate. Also, it is not essential to fix the stopped cylinder to a predetermined cylinder. For example, the cylinder to which fuel supply is stopped may be changed for each combustion cycle.

- The GPF 34 is not limited to a filter carrying a three-way catalyst, and may be a filter alone. Further, the GPF 34 is not limited to one provided downstream of the three-way catalyst 32 in the exhaust passage 30 . Also, the three-way catalyst 32 may be replaced with an oxidation catalyst that oxidizes the components contained in the exhaust gas. Moreover, providing the GPF 34 as an exhaust purification device itself is not essential.

- You may calculate 1st output gas temperature Tout1 in a different aspect from the said embodiment.
- The control device is not limited to one that includes the CPU 72 and the ROM 74 and executes software processing. For example, a dedicated hardware circuit such as an ASIC may be provided to perform hardware processing at least part of what is software processed in the above embodiments. That is, the control device 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 ROM 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 execution devices provided with a processing device and a program storage device, or a plurality of dedicated hardware circuits.

- The vehicle is not limited to a series/parallel hybrid vehicle, and may be, for example, a parallel hybrid vehicle or a series hybrid vehicle. However, the vehicle is not limited to a hybrid vehicle, and may be a vehicle having only the internal combustion engine 10 as a power generation device of the vehicle, for example.

DESCRIPTION OF SYMBOLS 10... Internal combustion engine 12... Intake passage 12a... Intake port 14... Throttle valve 16... Port injection valve 18... Intake valve 20... Combustion chamber 22... In-cylinder injection valve 24... Spark plug 26... Crankshaft 28... Exhaust valve 30... Exhaust Passage 32 Three-way catalyst 34 GPF
50... Planetary gear mechanism 52... First motor generator 54... Second motor generator 60... Drive wheel 70... Control device 72... CPU
74 ROM
80 Air flow meter 82 Crank angle sensor 86 Water temperature sensor 88 Exhaust pressure sensor

Claims (1)

Applied to an internal combustion engine having multiple cylinders,
specific cylinder stop processing for stopping fuel supply to some of the plurality of cylinders and performing fuel supply to remaining cylinders other than the some cylinders;
all-cylinder stop processing for stopping fuel supply to all cylinders;
a temperature calculation process for calculating a gas temperature, which is the temperature of the gas discharged from the cylinder of the internal combustion engine to the exhaust passage,
The temperature calculation process includes a process of calculating the gas temperature based on the temperature of the exhaust passage during execution of the all-cylinder stop process, and a process of calculating the gas temperature based on the temperature of the exhaust passage during execution of the specific cylinder stop process. a process of calculating the gas temperature of the stopped cylinder based on the flow rate of the gas discharged from the cylinder and the engine water temperature.

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