JP7001015B2 - Internal combustion engine control device - Google Patents

Description

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

Patent Document 1 discloses an internal combustion engine using gasoline as fuel. A three-way catalyst that purifies the exhaust gas is arranged in the exhaust passage of the internal combustion engine. A particulate filter that collects particulate matter is arranged downstream of the three-way catalyst in the exhaust passage.

In the internal combustion engine described in Patent Document 1, combustion in the cylinder may be stopped when the load applied to the internal combustion engine is low when the required torque for the internal combustion engine is reduced due to the cancellation of the accelerator operation or the like. be. During this combustion stop period, a fuel introduction process for regenerating the particulate filter is executed. That is, in the fuel introduction process, fuel is injected from the fuel injection valve, and the fuel is discharged from the cylinder to the exhaust passage without being burned. Then, when the fuel is introduced into the three-way catalyst, the temperature of the three-way catalyst rises due to the combustion of the fuel. Then, the high-temperature gas flows into the particulate filter, and the temperature of the particulate filter rises. As a result, the particulate matter collected in the particulate filter is burned.

U.S. Patent Application Publication No. 2014/0041362

In a technique such as Patent Document 1, the temperature of the particulate filter is increased by transferring the heat stored in the three-way catalyst by the gas flowing through the three-way catalyst and flowing into the particulate filter. The temperature of the three-way catalyst changes according to the amount of fuel supplied through the fuel introduction process. Therefore, it is conceivable to calculate the temperature of the particulate filter that changes under the influence of the change in the temperature of the three-way catalyst according to the fuel injection amount from the fuel injection valve and the like. However, when the above fuel introduction process is executed, it takes time for the heat to spread to the entire three-way catalyst from the time when the temperature of the three-way catalyst starts to rise until the high-temperature gas from the three-way catalyst reaches the particulate filter. There is a time delay depending on the distance between the three-way catalyst and the particulate filter. If the temperature of the particulate filter is calculated without considering such a time delay, there is a possibility that a large discrepancy may occur between the actual temperature of the particulate filter and the calculated temperature.

The control device of the internal combustion engine for solving the above problems is composed of an air flow meter that detects the amount of intake air, a ternary catalyst that is arranged in the exhaust passage and purifies the exhaust, and the ternary catalyst in the exhaust passage. It is also located on the downstream side and is equipped with a particulate filter that collects the particulate matter contained in the exhaust, and the air-fuel mixture containing the fuel injected from the fuel injection valve is introduced into the cylinder by the spark discharge of the ignition device. It is applied to an internal combustion engine that burns in, and when the combustion in the cylinder is stopped under the condition that the crank shaft of the internal combustion engine is rotating, fuel is injected from the fuel injection valve and the fuel is not burned. It is a control device that executes the fuel introduction process of flowing out from the inside of the cylinder to the exhaust passage as it is. A temperature calculation unit for calculating the provisional temperature of the particulate filter is provided, and the temperature calculation unit is provisional for the particulate filter before a predetermined period during the fuel injection process and within a specified period from the end of the fuel injection process. The current temperature of the particulate filter is calculated based on the temperature.

In the above configuration, the provisional temperature is calculated using the fuel injection amount during the fuel injection process that affects the temperature of the three-way catalyst, and the provisional temperature is the temperature of the three-way catalyst due to the fuel introduction process. The change is reflected. Here, it takes a considerable amount of time for the gas heated by the three-way catalyst to reach the particulate filter, depending on the distance between the three-way catalyst and the particulate filter. In the above configuration, by reflecting the provisional temperature before a predetermined period in the current temperature, it is possible to simulate the time delay until the gas heated by the three-way catalyst reaches the particulate filter. Therefore, it is possible to prevent the calculated current temperature of the particulate filter from deviating from the actual temperature of the particulate filter.

Schematic diagram of the hybrid system. Schematic diagram of an internal combustion engine. The flowchart which showed the processing procedure which concerns on the injection valve control processing. A time chart showing an example of the time change of the installation process execution flag and the installation process completion flag. A flowchart showing the processing procedure related to the upstream temperature calculation processing. A flowchart showing the processing procedure related to the middle basin temperature calculation processing. A flowchart showing the processing procedure related to the filter temperature calculation processing. A time chart showing examples of changes over time in the catalyst upstream temperature, catalyst midstream temperature, and filter temperature.

Hereinafter, an embodiment of the control device for an internal combustion engine will be described with reference to the drawings.
First, a schematic configuration of a hybrid system in a hybrid vehicle will be described.
As shown in FIG. 1, the hybrid vehicle includes an internal combustion engine 10, a power distribution integration mechanism 40 connected to the crank shaft 14 of the internal combustion engine 10, and a first motor generator connected to the power distribution integration mechanism 40. It is equipped with 71. A second motor generator 72 is connected to the power distribution integration mechanism 40 via a reduction gear 50, and a drive wheel 62 is connected via a reduction mechanism 60 and a differential 61.

The power distribution integrated mechanism 40 is a planetary gear mechanism, and has a sun gear 41 of an external gear and a ring gear 42 of an internal gear coaxially arranged with the sun gear 41. A plurality of pinion gears 43 that mesh with both the sun gear 41 and the ring gear 42 are arranged between the sun gear 41 and the ring gear 42. Each pinion gear 43 is supported by the carrier 44 in a state where it can rotate and revolve freely. A first motor generator 71 is connected to the sun gear 41. A crank shaft 14 is connected to the carrier 44. A ring gear shaft 45 is connected to the ring gear 42, and both the reduction gear 50 and the reduction mechanism 60 are connected to the ring gear shaft 45.

When the output torque of the internal combustion engine 10 is input to the carrier 44, the output torque is distributed to the sun gear 41 side and the ring gear 42 side. That is, by inputting the output torque of the internal combustion engine 10 to the first motor generator 71, the first motor generator 71 can generate electricity.

On the other hand, when the first motor generator 71 is made to function as an electric motor, the output torque of the first motor generator 71 is input to the sun gear 41. Then, the output torque of the first motor generator 71 input to the sun gear 41 is distributed to the carrier 44 side and the ring gear 42 side. Then, the output torque of the first motor generator 71 is input to the crank shaft 14 via the carrier 44, so that the crank shaft 14 can be rotated. In the present embodiment, rotating the crank shaft 14 by driving the first motor generator 71 in this way is referred to as "motoring".

The reduction gear 50 is a planetary gear mechanism and has a sun gear 51 of an external gear to which a second motor generator 72 is connected and a ring gear 52 of an internal gear coaxially arranged with the sun gear 51. There is. A ring gear shaft 45 is connected to the ring gear 52. Further, a plurality of pinion gears 53 that mesh with both the sun gear 51 and the ring gear 52 are arranged between the sun gear 51 and the ring gear 52. Although each pinion gear 53 is rotatable, it cannot revolve.

Then, when decelerating the vehicle, by making the second motor generator 72 function as a generator, it is possible to generate a regenerative braking force in the vehicle according to the amount of power generated by the second motor generator 72. When the second motor generator 72 is made to function as an electric motor, the output torque of the second motor generator 72 is input to the drive wheels 62 via the reduction gear 50, the ring gear shaft 45, the reduction mechanism 60, and the differential 61. Will be done. As a result, the drive wheels 62 can be rotated, that is, the vehicle can be driven.

The first motor generator 71 transfers electric power to and from the battery 77 via the first inverter 75. The second motor generator 72 transfers power to and from the battery 77 via the second inverter 76.

As shown in FIG. 2, a reciprocating piston 12 is housed in the cylinder 11 of the internal combustion engine 10. The piston 12 is connected to the crank shaft 14 via a connecting rod 13. An air flow meter 80 for detecting the amount of intake air is arranged in the intake passage 15 of the internal combustion engine 10. A throttle valve 16 for opening and closing the flow path of the intake passage 15 is provided on the downstream side of the air flow meter 80 in the intake passage 15 in order to adjust the amount of intake air into the cylinder 11. Further, the internal combustion engine 10 is provided with a fuel injection valve 17 for injecting fuel into a portion downstream of the throttle valve 16 in the intake passage 15. Fuel and air are introduced into the cylinder 11 via the intake passage 15 when the intake valve 18 is open. Then, in the cylinder 11, the spark discharge of the ignition device 19 burns the air-fuel mixture containing the air introduced through the intake passage 15 and the fuel injected from the fuel injection valve 17. Then, the exhaust gas generated in the cylinder 11 due to the combustion of the air-fuel mixture is discharged to the exhaust passage 21 when the exhaust valve 20 is open. The exhaust passage 21 is provided with a three-way catalyst 22 for purifying the exhaust gas and a particulate filter 23 arranged on the downstream side of the three-way catalyst 22. The particulate filter 23 has a function of collecting particulate matter contained in the exhaust gas flowing through the exhaust passage 21. An air-fuel ratio sensor 81 for detecting the oxygen concentration in the gas flowing through the exhaust passage 21, that is, the air-fuel ratio of the air-fuel mixture is arranged upstream of the three-way catalyst 22 in the exhaust passage 21.

In the internal combustion engine 10, combustion of the air-fuel mixture in the cylinder 11 may be stopped when the vehicle is running and the crank shaft 14 is rotating. The period during which combustion of the air-fuel mixture in the cylinder 11 is stopped when the crank shaft 14 is rotating is referred to as a "combustion stop period". During the combustion stop period, the piston 12 reciprocates in synchronization with the rotation of the crank shaft 14. Therefore, the air introduced into the cylinder 11 via the intake passage 15 flows out to the exhaust passage 21 without being subjected to combustion.

During the combustion stop period, a fuel cut process for stopping the fuel injection of the fuel injection valve 17 and a fuel introduction for injecting fuel from the fuel injection valve 17 and causing the fuel to flow out from the cylinder 11 to the exhaust passage 21 without being burned. One of the processes is selected and executed. When the fuel introduction process is executed, the fuel injected from the fuel injection valve 17 flows through the exhaust passage 21 together with the air. Then, the fuel is introduced into the three-way catalyst 22. At this time, when the temperature of the three-way catalyst 22 is equal to or higher than the activation temperature, if a sufficient amount of oxygen is present in the three-way catalyst 22 to burn the fuel, the fuel is burned by the three-way catalyst 22. As a result, the temperature of the three-way catalyst 22 rises. Then, the high-temperature gas flows into the particulate filter 23, and the temperature of the particulate filter 23 rises. When oxygen is supplied to the particulate filter 23, when the temperature of the particulate filter 23 becomes equal to or higher than the combustible temperature, the particulate matter collected in the particulate filter 23 is burned.

Next, the control configuration of the hybrid vehicle will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the control device 100 of the hybrid vehicle calculates the required torque TQR, which is the torque to be output to the ring gear shaft 45, based on the accelerator opening ACC and the vehicle speed VS. The accelerator opening ACC is an operation amount of the accelerator pedal AP by the driver of the vehicle, and is a value detected by the accelerator opening sensor 84. The vehicle speed VS is a value corresponding to the moving speed of the vehicle, and is detected by the vehicle speed sensor 85. The control device 100 controls the internal combustion engine 10 and the motor generators 71 and 72 based on the calculated required torque TQR.

The control device 100 includes an internal combustion engine control unit 110 that controls the internal combustion engine 10, and a motor control unit 120 that controls the motor generators 71 and 72. The internal combustion engine control unit 110 is an example of the “internal combustion engine control device” in the present embodiment. When the fuel introduction process is executed during the combustion stop period, the motor control unit 120 controls the drive of the first motor generator 71 for motoring. That is, the rotation speed of the crank shaft 14 can be controlled during the combustion stop period through the execution of motoring.

As shown in FIG. 2, the air-fuel ratio detection value AF, which is the air-fuel ratio detected by the air-fuel ratio sensor 81, is input to the internal combustion engine control unit 110. Further, an air amount detection value DR, which is an intake air amount detected by the air flow meter 80, is input to the internal combustion engine control unit 110. Further, the crank position detection value θ, which is the rotation position of the crank shaft 14 detected by the crank angle sensor 82, is input to the internal combustion engine control unit 110. Detection values from other sensors attached to various parts of the internal combustion engine 10 are also input to the internal combustion engine control unit 110.

As shown in FIG. 2, the internal combustion engine control unit 110 has an ignition control unit 111 that controls the ignition device 19, an injection valve control unit 112 that controls the fuel injection valve 17, and parameters related to the intake air amount as functional units. It has an air amount calculation unit 113 for calculating the temperature, and a temperature calculation unit 114 for calculating the temperature of the three-way catalyst 22 and the particulate filter 23.

When the ignition flag, which is a flag indicating permission for spark discharge, is turned on, the ignition control unit 111 causes the ignition device 19 to perform spark discharge at the timing when the piston reaches the vicinity of the compression top dead center. On the other hand, the ignition control unit 111 does not cause the ignition device 19 to perform spark discharge when the ignition flag is off, that is, during the combustion stop period.

The injection valve control unit 112 executes a fuel combustion process for burning fuel in the cylinder 11, a fuel cut process, and a fuel introduction process. When executing each process, the injection valve control unit 112 calculates the required value QPR of the fuel injection amount in the fuel injection valve 17, and controls the drive of the fuel injection valve 17 based on the required value QPR. The injection valve control unit 112 calculates the required value QPR of the fuel injection amount according to the operating state of the internal combustion engine 10 in each process.

The air amount calculation unit 113 calculates the total air integrated amount ADR, which is the cumulative value of the air amount detection value DR since the internal combustion engine control unit 110 is started. Specifically, the air amount calculation unit 113 sets the total air integrated amount ADR to “0” when the control device 100 of the hybrid vehicle is activated. Then, the air amount calculation unit 113 acquires the air amount detection value DR every predetermined cycle (for example, every several milliseconds) while the control device 100 of the hybrid vehicle is activated, and the acquired air amount detection value DR. Are sequentially accumulated to calculate the total air integrated amount ADR.

Further, when the injection valve control unit 112 executes the fuel introduction process, the air amount calculation unit 113 calculates the integrated amount UDR after introduction, which is the cumulative value of the air amount detection value DR from the time when the fuel introduction process is completed. calculate. Specifically, the air amount calculation unit 113 sets the post-introduction integrated amount UDR to “0” during the execution of the fuel introduction process. Then, the air amount calculation unit 113 acquires the air amount detection value DR every predetermined cycle (for example, every several milliseconds) from the time when the fuel introduction process is completed, and sequentially accumulates the acquired air amount detection value DR. After the introduction, the integrated amount UDR will be calculated.

The temperature calculation unit 114 individually calculates the temperature in the upstream region (hereinafter referred to as the catalyst upstream temperature UT) and the temperature in the midstream region (hereinafter referred to as the catalyst midstream temperature MT) in the three-way catalyst 22. During the execution of the fuel introduction process, the temperature calculation unit 114 calculates the catalyst upstream temperature UT and the catalyst midstream temperature MT based on the fuel injection amount from the fuel injection valve 17 in the fuel introduction process.

The temperature calculation unit 114 executes a filter temperature calculation process for calculating the temperature of the particulate filter 23 (hereinafter, referred to as a filter temperature FT). The filter temperature calculation process can be roughly divided into a process of calculating the provisional temperature of the particulate filter 23 (hereinafter, referred to as a filter provisional temperature FT1) and a process of calculating the filter temperature FT.

During the execution of the fuel introduction process, the temperature calculation unit 114 filters based on the catalyst midstream temperature MT calculated based on the fuel injection amount from the fuel injection valve 17 in the fuel introduction process and the air amount detection value DR. The provisional temperature FT1 is calculated. The temperature calculation unit 114 calculates the filter provisional temperature FT1 based on the operating state of the internal combustion engine 10 during the execution of the fuel combustion process. Further, the temperature calculation unit 114 calculates a predetermined initial value as the filter provisional temperature FT1 during the execution of the fuel cut process. Further, the temperature calculation unit 114 stores the filter provisional temperature FT1 calculated according to each process in association with the total air integrated amount ADR.

The temperature calculation unit 114 calculates the filter temperature FT based on the filter provisional temperature FT1 before the predetermined period during the fuel introduction process and within the specified period from the end of the fuel introduction process. In the present embodiment, the specified period is determined based on the post-introduction integrated amount UDR. That is, the period from the time when the fuel introduction process is completed until the integrated amount UDR after introduction reaches the specified value FSP for the filter, which is a predetermined specified value, corresponds to the above-mentioned specified period. The specified value FSP for the filter is, for example, the volume from the center of the three-way catalyst 22 in the exhaust passage 21 to the upstream end of the particulate filter 23.

Further, in the present embodiment, before the predetermined period, it is determined based on the total air integrated amount ADR. Here, the total air integrated amount ADR continues to increase from the start of the internal combustion engine control unit 110 until the end of operation. Therefore, the total air integrated amount ADR can also be regarded as a parameter representing the length of time after the internal combustion engine control unit 110 is started. For example, it is assumed that the total air integrated amount ADR increases to "X" after the internal combustion engine control unit 110 is started. The filter provisional temperature FT1 calculated when the total air integrated amount ADR is smaller than X reflects the information of the timing past the timing when the total air integrated amount ADR becomes “X”. In the present embodiment, the filter temperature FT is set based on the state in which the total air integrated amount ADR is a predetermined amount V less than the present, that is, the filter provisional temperature FT1 calculated at the stage before the predetermined amount V with respect to the total air integrated amount ADR. calculate.

Next, the procedure of the injection valve control process, which is the process of controlling the drive of the fuel injection valve 17 by the injection valve control unit 112, will be described with reference to FIG. The injection valve control unit 112 executes the following processing every predetermined control cycle (for example, every several milliseconds) while the control device 100 (internal combustion engine control unit 110) of the hybrid vehicle is activated.

When the injection valve control unit 112 starts the injection valve control process, the injection valve control unit 112 executes the process of step S10. In step S10, the injection valve control unit 112 determines whether or not the condition for stopping the combustion of the air-fuel mixture in the cylinder 11 is satisfied. The condition for stopping the combustion of the air-fuel mixture in the cylinder 11 is, for example, that the required value of the output torque for the internal combustion engine 10 is "0" or less. When the required value of the output torque for the internal combustion engine 10 is larger than "0", the injection valve control unit 112 determines that the condition for stopping the combustion of the air-fuel mixture in the cylinder 11 is not satisfied (step S10: NO). .. In this case, the injection valve control unit 112 advances the process to step S50. Then, the injection valve control unit 112 sets the ignition flag to ON in step S50. Further, in the subsequent step S55, the injection valve control unit 112 sets the introduction process execution flag, which is a flag indicating that the fuel introduction process is being executed, to off. After that, the injection valve control unit 112 advances the process to step S60. When the process proceeds to step S55, the motor control unit 120 stops the motoring if the motoring is being executed at that time.

In step S60, the injection valve control unit 112 calculates the required value QPR of the fuel injection amount of the fuel injection valve 17. The injection valve control unit 112 calculates the required value QPR so that the air-fuel ratio detection value AF becomes the target air-fuel ratio. The target air-fuel ratio is set to, for example, the theoretical air-fuel ratio or a value near the theoretical air-fuel ratio. The injection valve control unit 112 advances the process to step S65 after the process of step S60.

In step S65, the injection valve control unit 112 controls the drive of the fuel injection valve 17 based on the calculated required value QPR. Then, the injection valve control unit 112 temporarily ends a series of processes. The processes of steps S50, S60, and S65 are fuel combustion processes in which the air-fuel mixture containing the fuel injected from the fuel injection valve 17 is burned in the cylinder 11 of the internal combustion engine 10.

On the other hand, when the required value of the output torque for the internal combustion engine 10 is "0" or less in the determination of step S10, the injection valve control unit 112 satisfies the condition of stopping the combustion of the air-fuel mixture in the cylinder 11. (Step S10: YES). Then, the injection valve control unit 112 advances the process to step S15. Then, the injection valve control unit 112 sets the ignition flag to off, and proceeds to the process in step S20. While the ignition flag is set to off, the internal combustion engine 10 is in the combustion stop period.

In step S20, the injection valve control unit 112 determines whether or not the execution condition of the fuel introduction process is satisfied. In this embodiment, there are two execution conditions for the fuel introduction process. One of the execution conditions is that both the catalyst upstream temperature UT and the catalyst midstream temperature MT are above the specified temperature. The specified temperature is set to an activation temperature of the three-way catalyst 22 or a temperature slightly higher than the activation temperature. Another one of the above execution conditions is that the estimated value of the collected amount of the particulate matter in the particulate filter 23 is equal to or larger than the determined collected amount. As the amount of collection increases, the differential pressure between the portion between the three-way catalyst 22 and the particulate filter 23 in the exhaust passage 21 and the portion downstream of the particulate filter 23 in the exhaust passage 21 tends to increase. Therefore, for example, an estimated value of the collected amount can be calculated based on the differential pressure.

In step S20, when the injection valve control unit 112 determines that one or both of the above two execution conditions are not satisfied (step S20: NO), the process proceeds to step S80. Then, in step S80, the injection valve control unit 112 sets the introduction process execution flag to off. After that, the injection valve control unit 112 advances the process to step S85. When the process proceeds to step S80, the motor control unit 120 stops the motoring if the motoring is being executed at that time.

In step S85, the injection valve control unit 112 sets the required value QPR of the fuel injection amount in the fuel injection valve 17 to "0". Then, in the subsequent step S90, the injection valve control unit 112 controls the drive of the fuel injection valve 17 based on the required value QPR. That is, in this case, fuel is not injected from the fuel injection valve 17. When the process of step S90 is executed, the injection valve control unit 112 temporarily ends a series of processes. The processes of steps S15, S85, and S90 are fuel cut processes in which combustion in the cylinder 11 is stopped under the condition that the crank shaft 14 of the internal combustion engine 10 is rotating, and fuel is not introduced into the cylinder 11. Is.

On the other hand, in step S20, when the injection valve control unit 112 determines that both of the two execution conditions of the fuel introduction process are satisfied (step S20: YES), the process proceeds to step S25. In step S25, the injection valve control unit 112 determines whether or not the filter temperature FT is equal to or higher than the predetermined temperature. This predetermined temperature is predetermined by an experiment or the like as a value capable of burning the particulate matter collected in the particulate filter 23 when the fuel is injected from the fuel injection valve 17 in the fuel introduction process. Has been done. When the injection valve control unit 112 determines that the temperature of the particulate filter 23 is lower than the predetermined temperature (step S25: NO), the process proceeds to step S80. In this case, the fuel cut process described above is executed.

On the other hand, in step S25, when the injection valve control unit 112 determines that the filter temperature FT is equal to or higher than the predetermined temperature (step S25: YES), the process proceeds to step S30. Then, the injection valve control unit 112 sets the introduction process execution flag to ON in step S30. As the process proceeds to step S30, the motor control unit 120 executes motoring. After that, the injection valve control unit 112 advances the process to step S35.

In step S35, the injection valve control unit 112 calculates the required value QPR of the fuel injection amount for the fuel introduction process. The injection valve control unit 112 calculates the required value QPR based on the operating state of the internal combustion engine 10. The fuel injection amount for flowing out the fuel from the cylinder 11 to the exhaust passage 21 without being burned in the fuel introduction process is smaller than the fuel injection amount when the air-fuel mixture is burned in the cylinder 11 in the fuel combustion process. .. Therefore, the required value QPR calculated in step S35 is smaller than the required value QPR calculated in step S60. The injection valve control unit 112 advances the process to step S40 after step S35.

In step S40, the injection valve control unit 112 controls the drive of the fuel injection valve 17 based on the calculated required value QPR. Then, the injection valve control unit 112 temporarily ends a series of processes. In the processes of steps S15, S35, and S40, fuel is injected from the fuel injection valve 17 when the combustion in the cylinder 11 is stopped under the condition that the crank shaft 14 of the internal combustion engine 10 is rotating. This is a fuel injection process in which the fuel is discharged from the cylinder 11 to the exhaust passage 21 without being burned.

The injection valve control unit 112 updates the value of the introduction process completion flag, which is a flag indicating that the fuel introduction process is completed, while the above process is repeatedly executed. Specifically, the injection valve control unit 112 sets the introduction processing completion flag to "0" when the control device 100 of the hybrid vehicle is activated. Further, the injection valve control unit 112 sets the introduction process completion flag to "0" even when the introduction process execution flag is on. Then, when the introduction process execution flag is turned from on to off, the injection valve control unit 112 sets the introduction process completion flag to “1”. Therefore, as shown in FIG. 4, the introduction process completion flag is "0" from the start of the internal combustion engine control unit 110 until the first fuel introduction process is completed, and the first fuel introduction process is performed. When completed, the introduction process completion flag is set to "1". After that, the introduction process completion flag is updated to "1" during the period when the fuel introduction process is not executed (fuel combustion process or fuel cut process is executed), and to "0" during the execution of the fuel introduction process. Is repeated.

Next, the procedure of the upstream temperature calculation process executed by the temperature calculation unit 114 for calculating the catalyst upstream temperature UT will be described with reference to FIG. The temperature calculation unit 114 sets the catalyst upstream temperature UT to a predetermined constant for the catalyst upstream when the control device 100 of the hybrid vehicle is activated. Further, the temperature calculation unit 114 sets the upstream additional temperature UP, which is a correction value for the catalyst upstream temperature UT, to "0" when the control device 100 of the hybrid vehicle is activated. Further, the temperature calculation unit 114 is a holding value for reflecting the increase in the catalyst upstream temperature UT due to the fuel introduction process in the catalyst midstream temperature MT after the fuel introduction process is completed when the control device 100 of the hybrid vehicle is started. Set H to "0". Then, the temperature calculation unit 114 executes the following upstream temperature calculation process every predetermined control cycle (for example, every few seconds) while the control device 100 of the hybrid vehicle is activated. This control cycle is longer than the cycle in which the air amount calculation unit 113 calculates the total air integrated amount ADR.

When the temperature calculation unit 114 starts the upstream temperature calculation process, the temperature calculation unit 114 executes the process of step S200. In step S200, the temperature calculation unit 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being executed. When the temperature calculation unit 114 determines that the ignition flag is on (step S200: YES), the temperature calculation unit 114 proceeds to step S205. Then, in step S205, the temperature calculation unit 114 calculates the first provisional temperature UT1 based on the operating state of the internal combustion engine 10. Specifically, the temperature calculation unit 114 stores a catalyst upstream map showing the relationship between the engine speed NE, the engine load KL, and the catalyst upstream temperature UT. The temperature calculation unit 114 is calculated based on the current engine rotation speed NE calculated based on the crank position detection value θ, the crank position detection value θ, and the air amount detection value DR with reference to the catalyst upstream map. The temperature corresponding to the current engine load KL is calculated as the first provisional temperature UT1. The temperature calculation unit 114 advances the process to step S215 after step S205.

On the other hand, in step S200, when the temperature calculation unit 114 determines that the ignition flag is off (step S200: NO), the process proceeds to step S210. Then, in step S210, the temperature calculation unit 114 calculates the initial value for the catalyst upstream as the first provisional temperature UT1. The temperature calculation unit 114 advances the process to step S215 after step S210.

In step S215, the temperature calculation unit 114 calculates the second provisional temperature UT2 by performing a smoothing process on the first provisional temperature UT1. Specifically, the temperature calculation unit 114 calculates the second provisional temperature UT2 using the following equation (1).

2nd provisional temperature UT2 = previous catalyst upstream temperature UTP + (1st provisional temperature UT1-previous catalyst upstream temperature UTP) x ratio A ... (1)
Here, the ratio A is a positive value smaller than 1. The ratio A is predetermined as a dedicated value for calculating the second provisional temperature UT2. As is clear from the formula (1), the second provisional temperature UT2 sets the difference between the first provisional temperature UT1 and the previously calculated catalyst upstream temperature UTP as a ratio A to the previous catalyst upstream temperature UTP. It is reflected by the corresponding weight. The temperature calculation unit 114 advances the process to step S220 after step S215.

In step S220, the temperature calculation unit 114 determines whether or not the introduction process execution flag is turned on, that is, whether or not the fuel introduction process is being executed. When the temperature calculation unit 114 determines that the introduction process execution flag is turned on (step S220: YES), the temperature calculation unit 114 advances the process to step S225. In step S225, the temperature calculation unit 114 calculates the provisional additional temperature UP1. Specifically, the temperature calculation unit 114 stores an additional upstream map showing the relationship between the fuel injection amount from the fuel injection valve 17 and the increase in the catalyst upstream temperature UT. The temperature calculation unit 114 refers to the map for upstream addition, and calculates the temperature corresponding to the required value QPR of the current fuel injection amount as the provisional addition temperature UP1. After that, the temperature calculation unit 114 advances the process to step S230.

In step S230, the temperature calculation unit 114 calculates the upstream addition temperature UP by performing a smoothing process on the provisional addition temperature UP1. The smoothing method is the same as the method represented by the above equation (1). That is, the temperature calculation unit 114 calculates the upstream additional temperature UP by using the following equation (2).

Upstream addition temperature UP = Previous upstream addition temperature UPP + (provisional addition temperature UP1-previous upstream addition temperature UPP) x ratio B ... (2)
Here, the ratio B is a positive value smaller than 1. The ratio B is predetermined as a dedicated value for calculating the upstream addition temperature UP. After step S230, the temperature calculation unit 114 advances the process to step S240.

On the other hand, in step S220, when the temperature calculation unit 114 determines that the introduction processing execution flag is off (step S220: NO), the temperature calculation unit 114 advances the processing to step S235. Then, in step S235, the temperature calculation unit 114 sets the upstream addition temperature UP to “0”. Then, the temperature calculation unit 114 advances the process to step S240.

In step S240, the temperature calculation unit 114 calculates the catalyst upstream temperature UT. Specifically, the temperature calculation unit 114 calculates the value obtained by adding the upstream additional temperature UP to the second provisional temperature UT2 as the catalyst upstream temperature UT. After that, the temperature calculation unit 114 advances the process to step S245.

In step S245, the temperature calculation unit 114 determines whether or not the introduction processing completion flag is “1”. When the temperature calculation unit 114 determines that the introduction processing completion flag is "1" (step S245: YES), the temperature calculation unit 114 advances the processing to step S250. In this case, the temperature calculation unit 114 updates the previous holding value HP as the current holding value H. Then, the temperature calculation unit 114 temporarily ends a series of processes.

On the other hand, in step S245, when the temperature calculation unit 114 determines that the introduction process completion flag is not "1" (step S245: NO), the process proceeds to step S255. In step S255, the temperature calculation unit 114 updates the holding value H to the current (latest) upstream addition temperature UP. Then, the temperature calculation unit 114 temporarily ends a series of processes.

According to the processes of steps S245, S250, and S255, the holding value H is "0" from the start of the internal combustion engine control unit 110 to the start of the first fuel introduction process. After that, if the fuel introduction process is being executed (introduction completion flag is "0"), the holding value H is sequentially updated, and while the introduction process completion flag is "1", the holding value is held. H is maintained at the upstream addition temperature UP at the last timing during execution of the fuel introduction process (introduction completion flag is “0”). The holding value H is used in the midstream temperature calculation process described below.

Next, the procedure of the midstream temperature calculation process executed by the temperature calculation unit 114 for calculating the catalyst midstream temperature MT will be described with reference to FIG. The temperature calculation unit 114 sets the catalyst midstream temperature MT to the initial value for catalyst midstream, which is a predetermined constant, when the control device 100 of the hybrid vehicle is activated. The initial value for midstream catalyst is the same as the initial value for upstream catalyst. The temperature calculation unit 114 sets the midstream additional temperature MP, which is a correction value for the catalyst midstream temperature MT, to “0” when the control device 100 of the hybrid vehicle is activated. Then, the temperature calculation unit 114 executes the following midstream temperature calculation process at the same control cycle as the upstream temperature calculation process while the control device 100 of the hybrid vehicle is activated. The temperature calculation unit 114 starts the middle basin temperature calculation process at the timing when the holding value H has been updated in the upstream temperature calculation process.

When the temperature calculation unit 114 starts the middle basin temperature calculation process, the temperature calculation unit 114 executes the process of step S400. In step S400, the temperature calculation unit 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being executed. When the temperature calculation unit 114 determines that the ignition flag is on (step S400: YES), the temperature calculation unit 114 proceeds to the process in step S405. Then, in step S405, the temperature calculation unit 114 calculates the first provisional temperature MT1 based on the operating state of the internal combustion engine 10. Specifically, the temperature calculation unit 114 stores a catalyst midstream diversion map showing the relationship between the engine speed NE, the engine load KL, and the catalyst midstream temperature MT. The temperature calculation unit 114 refers to the catalyst middle diversion map, and calculates the temperature corresponding to the current engine speed NE and the engine load KL as the first provisional temperature MT1. The contents of the catalyst middle flow map are the same as the contents of the catalyst upstream map. That is, the value of the catalyst upstream temperature UT in the catalyst upstream map is directly used as the catalyst midstream temperature MT, which is the catalyst midstream map. Therefore, the first provisional temperature MT1 calculated in step S405 is the same value as the first provisional temperature UT1 calculated in step S205 of the upstream temperature calculation process. The temperature calculation unit 114 advances the process to step S415 after step S405.

On the other hand, in step S400, when the temperature calculation unit 114 determines that the ignition flag is off (step S400: NO), the process proceeds to step S410. Then, in step S410, the temperature calculation unit 114 calculates the initial value for mid-catalyst diversion as the first provisional temperature MT1. As described above, the initial value for midstream catalyst is the same as the initial value for upstream catalyst. Therefore, the first provisional temperature MT1 calculated in step S410 is the same value as the first provisional temperature UT1 calculated in step S210 of the upstream temperature calculation process. The temperature calculation unit 114 advances the process to step S415 after step S410.

In step S415, the temperature calculation unit 114 calculates the second provisional temperature MT2 by performing a smoothing process on the first provisional temperature MT1. The temperature calculation unit 114 calculates the second provisional temperature MT2 by the same smoothing process as in step S215 of the upstream temperature calculation process. The ratio value used for the smoothing process is a value dedicated to this process (process of step S415). The temperature calculation unit 114 advances the process to step S420 after step S415.

In step S420, the temperature calculation unit 114 calculates the third provisional temperature MT3 by performing a smoothing process on the second provisional temperature MT2. The method of smoothing processing is the same as the method used in step S415. The ratio value used for the smoothing process is a value dedicated to this process (process in step S420). As described above, the first provisional temperature MT1 calculated in step S405 or step S410 is the same as the first provisional temperature UT1 calculated in step S205 or step S210 of the upstream temperature calculation process. In the midstream temperature calculation process, in addition to the smoothing process in step S415, further smoothing process is performed in step S420 to simulate that the catalyst midstream temperature MT changes with a delay with respect to the catalyst upstream temperature UT. .. The temperature calculation unit 114 advances the process to step S425 after step S420.

In step S425, the temperature calculation unit 114 determines whether or not the introduction process execution flag is turned on, that is, whether or not the fuel introduction process is being executed. When the temperature calculation unit 114 determines that the introduction process execution flag is turned on (step S425: YES), the temperature calculation unit 114 advances the process to step S430. Then, in step S430, the temperature calculation unit 114 calculates the provisional additional temperature MP1. Specifically, the temperature calculation unit 114 stores an additional midstream diversion map showing the relationship between the fuel injection amount from the fuel injection valve 17 and the increase in the catalyst midstream temperature MT. In addition, the effect that the gas raised in the upstream region of the three-way catalyst 22 due to the fuel introduction process reaches the midstream region and raises the catalyst midstream temperature MT is also taken into consideration for the increase in the catalyst midstream temperature MT in the additional midstream map. Has been done. The temperature calculation unit 114 refers to the map for midstream addition, and calculates the temperature corresponding to the required value QPR of the current fuel injection amount as the provisional addition temperature MP1. After that, the temperature calculation unit 114 advances the process to step S435.

On the other hand, in step S425, when the temperature calculation unit 114 determines that the introduction process execution flag is off (step S425: NO), the temperature calculation unit 114 advances the process to step S440. In step S440, the temperature calculation unit 114 determines whether or not the introduction processing completion flag is “1” and the integrated amount UDR after introduction is equal to or less than the specified value CSP for the catalyst. The specified value CSP for the catalyst determines whether or not the heat generated in the upstream region of the three-way catalyst 22 due to the fuel injection in the fuel introduction process has been transferred to the middle stream region of the three-way catalyst 22 using gas as a medium. It is defined as a value that can be determined. The specified value CSP for the catalyst is determined in consideration of the distance between the upstream end and the center of the three-way catalyst 22, and is obtained, for example, by repeating an experiment of increasing or decreasing the flow velocity of the gas flowing through the exhaust passage 21. It is determined based on the results. The following situations can be considered as the situations in which the determination in step S440 is YES. That is, after the fuel introduction process is completed, all the heat generated in the upstream region of the three-way catalyst 22 due to the fuel injection in the fuel introduction process has not been completely transferred to the middle stream region of the three-way catalyst 22. Under such circumstances, the heat generated in the upstream region of the three-way catalyst 22 can be transferred to the midstream region of the three-way catalyst 22 using gas as a medium to raise the catalyst midstream temperature MT. On the other hand, the situation where the determination in step S440 is NO is the situation where all the heat generated in the upstream region of the three-way catalyst 22 due to the fuel introduction process has been transferred to the middle stream region of the three-way catalyst 22, that is, the three-way catalyst. The situation is such that the gas flowing downstream from the catalyst 22 does not affect the catalyst midstream temperature MT. Further, the determination in step S440 is NO even during the period from the start of the internal combustion engine control unit 110 to the completion of the first fuel introduction process.

In step S440, when the temperature calculation unit 114 determines that the introduction processing completion flag is "1" and the integrated amount UDR after introduction is equal to or less than the specified value CSP for the catalyst (step S440: YES). , The process proceeds to step S445. Then, in step S445, the temperature calculation unit 114 calculates the holding value H as the provisional additional temperature MP1. As described above, while the introduction process completion flag is “1”, the holding value H is the upstream addition temperature UP at the final timing during the execution of the fuel introduction process. By calculating the holding value H as the provisional addition temperature MP1, the increase in the catalyst upstream temperature UT due to the fuel introduction process is reflected in the catalyst midstream temperature MT through the following step S435. After step S445, the temperature calculation unit 114 proceeds to step S435.

In step S435, the temperature calculation unit 114 calculates the midstream addition temperature MP by performing a smoothing process on the provisional addition temperature MP1. The smoothing method is the same as the method used in step S420. The ratio value used for the smoothing process is a value dedicated to this process (process of step S435). The temperature calculation unit 114 advances the process to step S455 after step S435.

In step S455, the temperature calculation unit 114 calculates the value obtained by adding the midstream addition temperature MP to the third provisional temperature MT3 as the catalyst midstream temperature MT. After that, the temperature calculation unit 114 temporarily ends a series of processes.

In step S440, the temperature calculation unit 114 has either a determination condition that the introduction processing completion flag is "1" or a determination condition that the integrated amount UDR after introduction is equal to or less than the specified value CSP for the catalyst. If it is not satisfied (step S440: NO), the process proceeds to step S450. In this case, the temperature calculation unit 114 calculates the midstream addition temperature MP as “0”. Then, the temperature calculation unit 114 proceeds to step S455 to calculate the catalyst midstream temperature MT.

Next, the procedure of the filter temperature calculation process executed by the temperature calculation unit 114 for calculating the filter temperature FT will be described with reference to FIG. 7. The temperature calculation unit 114 sets the filter temperature FT to a predetermined constant value for the filter when the control device 100 of the hybrid vehicle is activated. Then, the temperature calculation unit 114 executes the following filter temperature calculation process at the same control cycle as the upstream temperature calculation process while the control device 100 of the hybrid vehicle is activated. The temperature calculation unit 114 starts the filter temperature calculation process at the timing when the catalyst midstream temperature MT has been calculated in the midstream temperature calculation process.

When the temperature calculation unit 114 starts the filter temperature calculation process, the temperature calculation unit 114 executes the process of step S500. In step S500, the temperature calculation unit 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being executed. When the temperature calculation unit 114 determines that the ignition flag is on (step S500: YES), the temperature calculation unit 114 proceeds to the process in step S510.

In step S510, the temperature calculation unit 114 calculates the filter provisional temperature FT1 based on the operating state of the internal combustion engine 10. Specifically, the temperature calculation unit 114 stores the first map for the filter showing the relationship between the engine speed NE, the engine load KL, and the filter temperature FT. The temperature calculation unit 114 refers to the first map for the filter, and calculates the temperature corresponding to the current engine speed NE and the engine load KL as the filter provisional temperature FT1. The filter provisional temperature FT1 is a temperature at which the filter temperature FT converges in the future if the current engine speed NE and the current engine load KL are maintained over a future time. The temperature calculation unit 114 advances the process to step S550 after step S510.

On the other hand, if the temperature calculation unit 114 determines in step S500 that the ignition flag is off, the process proceeds to step S520. Then, in step S520, the temperature calculation unit 114 determines whether or not the introduction process execution flag is on, that is, whether or not the fuel introduction process is being executed. When the temperature calculation unit 114 determines that the introduction process execution flag is on (step S520: YES), the temperature calculation unit 114 proceeds to the process in step S530.

In step S530, the temperature calculation unit 114 calculates the filter provisional temperature FT1 based on the catalyst midstream temperature MT calculated by the midstream temperature calculation process and the current air amount detection value DR. Specifically, the temperature calculation unit 114 stores a second map for the filter showing the relationship between the catalyst midstream temperature MT, the intake air amount, and the filter temperature FT. The temperature calculation unit 114 refers to the second map for the filter, and calculates the temperature corresponding to the catalyst midstream temperature MT calculated by the midstream temperature calculation process and the current air amount detection value DR as the filter provisional temperature FT1. .. As described in the above midstream temperature calculation process, the catalyst midstream temperature MT during the fuel introduction process is calculated by reflecting the midstream additional temperature MP calculated based on the fuel injection amount from the fuel injection valve 17. Will be done. That is, the catalyst midstream temperature MT during the fuel introduction process is calculated using the fuel injection amount from the fuel injection valve 17. In step S530, the filter provisional temperature FT1 is calculated based on the catalyst midstream temperature MT calculated using the fuel injection amount from the fuel injection valve 17, so that the filter provisional temperature FT1 is from the fuel injection valve 17. It will be calculated using the fuel injection amount of. The filter provisional temperature FT1 is a temperature at which the filter temperature FT converges in the future if the current fuel injection amount and the current intake air amount are maintained over a future time. The temperature calculation unit 114 advances the process to step S550 after step S530.

If the temperature calculation unit 114 determines in step S520 that the introduction process execution flag is off (step S520: NO), the temperature calculation unit 114 proceeds to step S540. In step S540, the temperature calculation unit 114 calculates the initial value for the filter as the filter provisional temperature FT1. The filter provisional temperature FT1 is a temperature at which the filter temperature FT converges in the future if the current operating state of the internal combustion engine 10 is maintained for a future time. The temperature calculation unit 114 advances the process to step S550 after step S540.

In step S550, the temperature calculation unit 114 stores the filter provisional temperature FT1 and the current total air integrated amount ADR in association with each other. The air amount calculation unit 113 sequentially stores the associated filter provisional temperature FT1 and the total air integrated amount ADR as provisional temperature data in the time direction.

In step S600, the temperature calculation unit 114 determines whether or not the introduction process execution flag is on, that is, whether or not the fuel introduction process is being executed. When the temperature calculation unit 114 determines that the introduction process execution flag is on (step S600: YES), the temperature calculation unit 114 proceeds to the process in step S610.

On the other hand, in step S600, when the temperature calculation unit 114 determines that the introduction process execution flag is off (step S600: NO), the temperature calculation unit 114 advances the process to step S605. In step S605, the temperature calculation unit 114 determines whether or not the introduction processing completion flag is "1" and the integrated amount UDR after introduction is equal to or less than the specified value FSP for the filter. The specified value FSP for the filter can determine whether or not the heat generated in the middle basin of the three-way catalyst 22 due to the fuel injection in the fuel introduction process has been transferred to the particulate filter 23 through the gas as a medium. It is set as a value. The specified value FSP for the filter is determined in consideration of the distance between the center of the three-way catalyst 22 and the upstream end of the particulate filter 23, and for example, an experiment in which the flow velocity of the gas flowing through the exhaust passage 21 is increased or decreased. It is determined based on the result obtained by repeating. The following situations can be considered as the situations in which the determination in step S605 is YES. That is, after the fuel introduction process is completed, all the heat generated by the three-way catalyst 22 due to the fuel injection in the fuel introduction process has not been completely transferred to the particulate filter 23. Under such circumstances, the heat generated by the three-way catalyst 22 can be transferred to the particulate filter 23 using the gas as a medium to raise the filter temperature FT. On the other hand, the situation where the determination in step S605 is NO is the situation where all the heat generated in the three-way catalyst 22 due to the fuel introduction process has been transferred to the particulate filter 23, that is, the heat flows downstream from the three-way catalyst 22. The situation is such that the gas does not affect the filter temperature FT. Further, the determination in step S605 is NO even during the period from the start of the internal combustion engine control unit 110 to the completion of the first fuel introduction process.

In step S605, when the temperature calculation unit 114 determines that the introduction processing completion flag is "1" and the integrated amount UDR after introduction is equal to or less than the specified value FSP for the filter (step S605: YES), the processing is performed. To step S610.

In step S610, the temperature calculation unit 114 refers to the provisional temperature data created in step S550 described above, and the filter provisional temperature FT1 when the total air integrated amount ADR is a predetermined amount V smaller than the current total air integrated amount ADR. Is calculated with an interpolation calculation. The following method can be considered as an example of interpolation calculation. For example, a plurality of total air integrations in which the total air integration amount ADR (total air integration amount ADR when a predetermined amount V is smaller than the current total air integration amount ADR) required in step S610 is stored in the provisional temperature data. It is assumed that the value "QX" is between "Q1" and "Q2", which are two of the quantities ADR. In this case, the temperature calculation unit 114 uses the filter provisional temperature FTQ1 when the total air integrated amount ADR is "Q1" and the filter provisional temperature FTQ2 when the total air integrated amount ADR is "Q2". A linear function expressing the relationship between the filter provisional temperature FT1 and the total air integrated amount ADR by a linear equation is calculated. Then, in this linear function, the filter provisional temperature FT1 when the total air integrated amount ADR is "QX" is calculated.

As described above, the temperature calculation unit 114 calculates the filter provisional temperature FT1 when the total air integrated amount ADR is a predetermined amount V smaller than the current total air integrated amount ADR. Then, the temperature calculation unit 114 sets the calculated filter provisional temperature FT1 to the final provisional temperature FT3. The timing at which the total air integrated amount ADR is a predetermined amount V smaller than the current total air integrated amount ADR is before the present, that is, at the past timing. Here, the filter provisional temperature FT1 is a value for considering that the gas located upstream of the particulate filter 23 in the past timing reaches the particulate filter 23 and affects the filter temperature FT. be. Therefore, the predetermined amount V is defined as an amount corresponding to a time scale that can capture the timing at which the gas flowing downstream from the three-way catalyst 22 affects the filter temperature FT. The predetermined amount V is determined in consideration of the distance between the center of the three-way catalyst 22 and the upstream end of the particulate filter 23, and for example, an experiment in which the flow velocity of the gas flowing through the exhaust passage 21 is increased or decreased. It is determined based on the results obtained repeatedly.

The temperature calculation unit 114 advances the process to step S615 after step S610. In step S615, the temperature calculation unit 114 calculates the filter temperature FT by performing a smoothing process on the final provisional temperature FT3. The smoothing method is the same as the method used in step S215 of the upstream temperature calculation process, and is performed using the following equation (3).

Filter temperature FT = previous filter temperature FTP + (final provisional temperature FT3-previous filter temperature FTP) x ratio C ... (3)
The value of the ratio C is a value dedicated to this process (process of step S615). After step S615, the temperature calculation unit 114 temporarily ends a series of processes.

On the other hand, in step S605, the temperature calculation unit 114 has either a determination condition that the introduction processing completion flag is "1" or a determination condition that the integrated amount UDR after introduction is equal to or less than the specified value FSP for the filter. If it is not satisfied (step S605: NO), the process proceeds to step S620.

In step S620, the temperature calculation unit 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being executed. When the temperature calculation unit 114 determines that the ignition flag is on (step S620: YES), the temperature calculation unit 114 proceeds to the process in step S625. Then, in step S625, the temperature calculation unit 114 calculates the intermediate provisional temperature FT2 based on the operating state of the internal combustion engine 10. Specifically, the temperature calculation unit 114 refers to the first map for the filter used in step S510, and calculates the temperature corresponding to the current engine speed NE and the engine load KL as the intermediate provisional temperature FT2. After the processing in step S625, the temperature calculation unit 114 advances the processing to step S630.

On the other hand, if the temperature calculation unit 114 determines in step S620 that the ignition flag is off (step S620: NO), the process proceeds to step S635. In this case, the temperature calculation unit 114 calculates the initial value for the filter used in step S540 as the intermediate provisional temperature FT2. After that, the temperature calculation unit 114 proceeds to step S630.

In step S630, the temperature calculation unit 114 performs a smoothing process on the intermediate provisional temperature FT2 to calculate the final provisional temperature FT3. The smoothing method is the same as the method used in step S615. The value of the ratio used for the smoothing process is a value dedicated to step S630. After step S630, the temperature calculation unit 114 advances the process to step S615 to calculate the filter temperature FT. Then, the temperature calculation unit 114 temporarily ends a series of processes.

Next, the operation and effect of this embodiment will be described.
In the internal combustion engine 10, when the fuel is introduced into the three-way catalyst 22 in the fuel introduction process, the fuel is burned by the three-way catalyst 22, and the catalyst upstream temperature UT rises first. After that, in the midstream region of the three-way catalyst 22, the gas heated in the upstream region of the three-way catalyst 22 reaches the midstream region and raises the catalyst midstream temperature MT. Further, the gas heated in the midstream region of the three-way catalyst 22 flows downstream in the exhaust passage 21. Then, when this gas reaches the particulate filter 23, the temperature of the particulate filter 23 rises and the filter temperature FT rises. In this way, when the fuel introduction process is executed, heat spreads over the entire three-way catalyst 22 from the time when the fuel injection is executed and the catalyst upstream temperature UT starts to rise until the filter temperature FT rises. There is a time delay depending on the time, the distance between the three-way catalyst 22 and the particulate filter 23, and the like.

The temperature calculation unit 114 of the present embodiment calculates the catalyst upstream temperature UT, the catalyst midstream temperature MT, and the filter temperature FT in consideration of the fuel combustion amount in the three-way catalyst 22 and the time delay. Specifically, in the upstream temperature calculation process, the temperature calculation unit 114 burns fuel in the upstream region of the three-way catalyst 22 along with fuel injection when the fuel introduction process is executed, and the temperature is upstream of the catalyst. Considering that the UT rises, the upstream additional temperature UP is calculated based on the fuel injection amount (steps S225 and S230). Then, the temperature calculation unit 114 reflects this upstream addition temperature UP in the catalyst upstream temperature UT (step S240). Therefore, as shown in FIG. 8, if the fuel introduction process is executed between the time t1 and the time t2 after the control device 100 of the hybrid vehicle is started, the temperature calculation unit 114 temporarily performs the fuel introduction process during the same period. The catalyst upstream temperature UT (see the solid line in FIG. 8) higher than the temporary catalyst upstream temperature UTX (see the alternate long and short dash line in FIG. 8) calculated when the fuel cut process is executed without being executed is calculated.

In the midstream temperature calculation process, the temperature calculation unit 114 burns fuel in the midstream region of the three-way catalyst 22 along with fuel injection in the fuel introduction process when the fuel introduction process is executed. Considering that the temperature MT rises and that the gas heated in the upstream region of the three-way catalyst 22 reaches the midstream region, the midstream additional temperature MP is calculated based on the fuel injection amount in the fuel introduction process (step). S430, S435). Then, the temperature calculation unit 114 reflects this midstream addition temperature MP in the catalyst midstream temperature MT (step S455). Therefore, as shown in FIG. 8, the catalyst midstream temperature MT (see the solid line in FIG. 8) calculated by the temperature calculation unit 114 between the time t1 and the time t2 when the fuel introduction process is executed is the fuel cut process during the same period. Is higher than the temporary catalyst midstream temperature MTX (see one-dot chain line in FIG. 8) calculated assuming that is executed.

Further, in the middle basin temperature calculation process, the temperature calculation unit 114 of the three-way catalyst 22 after the completion of the fuel introduction process, while the integrated amount UDR after introduction is equal to or less than the specified value CSP for the catalyst (step S440: YES). Considering that the gas heated in the upstream region flows into the midstream region, the midstream addition temperature MP is calculated based on the upstream addition temperature UP stored as the holding value H (steps S445 and S435). That is, the temperature calculation unit 114 calculates the midstream addition temperature MP based on the increase in the catalyst upstream temperature UT accompanying the fuel introduction process. Then, the temperature calculation unit 114 reflects this midstream addition temperature MP in the catalyst midstream temperature MT (step S455). The resulting catalyst midstream temperature MT is the catalyst midstream temperature MT at the end of the fuel introduction process (fuel combustion in the midstream region of the three-way catalyst 22 and from the upstream side of the three-way catalyst 22 during the fuel introduction process. The increase in the catalyst upstream temperature UT is added to the temperature in consideration of the inflow of gas). Therefore, from the time t2 when the fuel introduction process is completed to the time t3 thereafter, the catalyst midstream temperature MT (see the solid line in FIG. 8) calculated by the temperature calculation unit 114 is said to have been subjected to the fuel cut process during the same period. It is higher than not only the provisional catalyst midstream temperature MTX calculated in the assumed case (see the one-point chain line in FIG. 8) but also the catalyst midstream temperature MT during the execution of the fuel introduction process (between time t1 and time t2).

In the filter temperature calculation process, the temperature calculation unit 114 considers that high-temperature gas flows from the midstream region of the three-way catalyst 22 to the particulate filter 23 during the execution of the fuel introduction process and after the fuel introduction process is completed. To calculate the filter temperature FT. Specifically, the temperature calculation unit 114 associates the total air integrated amount ADR with the filter provisional temperature FT1 calculated according to the process executed by the injection valve control unit 112 at each timing (step S550). With respect to the filter provisional temperature FT1, if the fuel introduction process is being executed, the temperature calculation unit 114 calculates a value reflecting the amount of fuel burned in the three-way catalyst 22 accompanying the fuel introduction process (step S530).

Then, the temperature calculation unit 114 is in the middle of executing the fuel introduction process (step S600: YES) and after the end of the fuel introduction process, while the integrated amount UDR after introduction is equal to or less than the specified value FSP for the filter (step S605: YES). ) Specify the filter provisional temperature FT1 at the timing when the total air integrated amount ADR is a predetermined amount V smaller than the current total air integrated amount ADR, that is, at the past timing (step S610). Then, the temperature calculation unit 114 calculates the filter temperature FT based on the filter provisional temperature FT1 (step S615). Here, it is assumed that the total air accumulation amount at an arbitrary time TX is "Z". The gas reaching the particulate filter 23 at this arbitrary time TX is located in the middle basin of the three-way catalyst 22 at the time TXa (total air integrated amount is “Zw”) before the time TX. ing. That is, in order to reflect the temperature in the midstream region of the three-way catalyst 22 located upstream of the particulate filter 23 when calculating the filter temperature FT at an arbitrary time TX, the time TXa (total air integrated amount) is used. It is conceivable to use the catalyst midstream temperature MT when “Z—w”) is used to calculate the filter temperature FT at an arbitrary time TX. This makes it possible to simulate the time delay until the gas flowing from the upstream side of the particulate filter 23 reaches the particulate filter 23. In the present embodiment, the filter provisional temperature FT1 at the timing when the total air integrated amount ADR is a predetermined amount V smaller than the current total air integrated amount ADR is reflected in the filter temperature FT. Therefore, according to the filter temperature calculation process of the present embodiment, the temperature calculation unit 114 sets the filter temperature FT in consideration of the time delay until the gas heated by the three-way catalyst 22 reaches the particulate filter 23. Can be calculated.

As described above, in the filter temperature calculation process, fuel combustion in the midstream region of the three-way catalyst 22 and gas flow from the upstream region of the three-way catalyst 22 are performed during the execution of the fuel introduction process and after the fuel introduction process is completed. The catalyst midstream temperature MT in consideration of the above is reflected in the filter temperature FT. From this, as shown in FIG. 8, the temperature calculation unit 114 is from time t1 to time t2 when the fuel introduction process is executed, and from time t2 when the fuel introduction process is completed to time t4 thereafter. The filter temperature FT calculated by (see the solid line in FIG. 8) is higher than the temporary filter temperature FTX (see the alternate long and short dash line in FIG. 8) calculated assuming that the fuel cut process is executed during the same period. In particular, the filter temperature FT becomes considerably higher than the temporary filter temperature FTX as the catalyst medium flow temperature MT increases at a time after the time t2 when the fuel introduction process is completed. Moreover, in the filter temperature calculation process, the time delay until the gas heated by the three-way catalyst 22 reaches the particulate filter 23 is taken into consideration, so that the filter temperature FT peaks after the fuel introduction process is completed. Is later than the time when the catalyst midstream temperature MT peaks.

As described above, in the present embodiment, the time delay until the gas heated by the three-way catalyst 22 reaches the particulate filter 23 is simulated. Therefore, it is possible to prevent the filter temperature FT calculated by the temperature calculation unit 114 from deviating from the actual temperature of the particulate filter 23.

In addition, this embodiment can be changed and carried out as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-The processing content of the filter temperature calculation processing can be changed. In the filter temperature calculation process of the above embodiment, the total air integrated amount ADR is used to reflect the filter provisional temperature FT1 before a predetermined period on the filter temperature FT. However, in order to reflect the filter provisional temperature FT1 before a predetermined period on the filter temperature FT, it is not always necessary to use the total air integrated amount ADR, and it is necessary to specify a predetermined period before the timing for calculating the filter temperature FT. You can use the parameters that can be used. For example, the air amount calculation unit 113 calculates the cumulative value of the air amount detection value DR from the time when the fuel introduction process is started every time the fuel introduction process is started. Then, in step S550, the temperature calculation unit 114 creates provisional temperature data in which the above cumulative value is associated with the filter provisional temperature FT1. Then, in step S610, the temperature calculation unit 114 converts the filter provisional temperature FT1 when the cumulative value of the air amount detection value DR from the time when the fuel introduction process is started is smaller than the current value by a predetermined amount into the provisional temperature data. Calculate based on. Temporary temperature is assumed that the cumulative value of the air amount detection value DR from the time when the fuel introduction process is started is smaller than the current value by a predetermined amount, which is the timing before the fuel introduction process is started. When the corresponding data does not exist in the data, for example, the filter provisional temperature FT1 at the time when the fuel introduction process is started, that is, at the time when the cumulative value is 0 may be reflected in the filter temperature FT.

-In the filter temperature calculation process of the above embodiment, the predetermined period for reflecting the filter provisional temperature FT1 before the predetermined period on the filter temperature FT is determined by the intake air amount (predetermined amount V). This predetermined period may be determined by time. For example, if the fluctuation of the intake air amount is not so large, the gas is discharged from the middle reaches of the three-way catalyst 22 based on the distance and volume from the center of the three-way catalyst 22 to the upstream end of the particulate filter 23. The time to reach the catalytic filter 23 can be estimated. The above-mentioned predetermined period may be set based on this time. When the predetermined period is determined by the time, for example, in step S550, the time from the time when the control device 100 of the hybrid vehicle is started, the time from the time when the fuel introduction process is started, and the filter provisional temperature FT1 are set. It may be created as provisional temperature data in association with each other, and the filter provisional temperature FT1 before a predetermined period may be calculated in step S610 based on the provisional temperature data.

In the filter temperature calculation process of the above embodiment, the specified period for determining whether or not the heat generated by the fuel introduction process has been transferred from the midstream region of the three-way catalyst 22 to the particulate filter 23 is set. It was determined by the amount of intake air (specified value FSP for the filter). However, the specified period may be set by time. For example, as described in the above modification example, if the fluctuation of the intake air amount is not so large, the gas will be generated based on the distance and volume from the center of the three-way catalyst 22 to the upstream end of the particulate filter 23. The time from the midstream region of the three-way catalyst 22 to the particulate filter 23 can be estimated. The above-mentioned specified period may be set based on this time.

The initial value for the filter used in steps S540 and S635 of the filter temperature calculation process is different from the value set as the initial value of the filter temperature FT by the temperature calculation unit 114 when the control device 100 of the hybrid vehicle is started. May be.

The filter temperature FT may be calculated using the catalyst upstream temperature UT. In this case, for example, in the filter temperature calculation process, the map used in steps S510 and S625, the map used in step S530, and the initial values used in steps S540 and S635 are changed to those corresponding to the catalyst upstream temperature UT. do it. Further, the specified value FSP for the filter used in step S605, the predetermined amount V used in step S610, the ratio used in step S615, and the ratio used in step S630 are set to the values corresponding to the upstream region of the three-way catalyst 22. You can change it. When calculating the filter temperature FT using the catalyst upstream temperature UT, it is not necessary to calculate the catalyst midstream temperature MT.

The method for calculating the filter temperature FT is not limited to that following the processing procedure of the filter temperature calculation process of the above embodiment. The filter temperature FT may not be calculated based on the catalyst upstream temperature UT or the catalyst midstream temperature MT. That is, the temperature calculation unit 114 does not calculate the temperature of the catalyst upstream temperature UT or the catalyst midstream temperature MT, and uses the fuel injection amount from the fuel injection valve 17 in the fuel introduction process to set the filter provisional temperature FT1 at regular intervals. calculate. At this time, if the effect of changes in the catalyst upstream temperature UT and the catalyst midstream temperature MT is reflected in the filter provisional temperature FT1, an appropriate temperature is calculated as the filter provisional temperature FT1. Specifically, the temperature calculation unit 114 uses the fuel injection amount from the fuel injection valve 17, and instead of the temperature of the three-way catalyst 22, heat is stored in the three-way catalyst 22 and then transmitted to the particulate filter 23. Calculate the index value of the amount of heat that will be. If the filter provisional temperature FT1 is calculated based on this, it is not necessary to calculate the catalyst upstream temperature UT or the catalyst midstream temperature MT.

-The processing content of the midstream temperature calculation processing can be changed. In the middle basin temperature calculation process of the above embodiment, the period for determining whether or not the gas heated by the fuel introduction process has reached the middle basin from the upstream region of the three-way catalyst 22 is the intake air. It was determined by the amount (specified value CSP for catalyst). However, the above period may be determined by time. For example, if the fluctuation of the intake air amount is not so large, the gas extends from the upstream region to the midstream region of the three-way catalyst 22 based on the distance and volume from the upstream end to the center of the three-way catalyst 22. Time can be estimated. The above period may be set based on this time.

The initial value for catalyst midstream used in step S410 of the midstream temperature calculation process is different from the value set by the temperature calculation unit 114 as the initial value of the catalyst midstream temperature MT when the control device 100 of the hybrid vehicle is started. May be.

-The midstream temperature calculation process of the above embodiment may be partially modified and applied as a process for calculating the temperature in the downstream area of the three-way catalyst 22. In this case, for example, the map used in step S405, the initial value used in step S410, the map used in step S430, the specified value used in step S440, and the ratio used in step S435 are set for each of the three-way catalyst 22. It may be changed to the one dedicated to the downstream area. In step S445, the increase in the catalyst upstream temperature UT in the fuel introduction process may be appropriately adjusted and used for the provisional addition temperature, or the increase in the catalyst midstream temperature MT in the fuel introduction process may be appropriately adjusted to be the provisional addition temperature. You may use it for.

-When calculating the temperature in the downstream region of the three-way catalyst 22 as in the above modification example, the temperature may be used for calculating the filter temperature FT. In this case, for example, in the filter temperature calculation process, the map used in steps S510 and S625, the map used in step S530, and the initial values used in steps S540 and S635 are set to the temperature in the downstream region of the three-way catalyst 22. You can change it to the corresponding one. Further, the specified value FSP for the filter used in step S605, the predetermined amount V used in step S610, the ratio used in step S615, and the ratio used in step S630 are set to the values corresponding to the downstream region of the three-way catalyst 22. You can change it.

-The processing content of the upstream temperature calculation process can be changed. The content of the catalyst upstream map used in step S205 may be different from the content of the catalyst midstream map used in step S405 of the midstream temperature calculation process. The initial value for upstream catalyst used in step S210 may be different from the initial value for intermediate catalyst used in step S410 of the midstream temperature calculation process. The initial value for the catalyst upstream used in step S210 may be different from the value set as the initial value of the catalyst upstream temperature UT by the temperature calculation unit 114 when the control device 100 of the hybrid vehicle is started. Further, the value set by the temperature calculation unit 114 as the initial value of the catalyst upstream temperature UT when the hybrid vehicle control device 100 is started is the value set by the temperature calculation unit 114 as the catalyst midstream temperature when the hybrid vehicle control device 100 is started. It may be different from the value set as the initial value of MT.

-In the above embodiment, the ignition device 19 is prevented from performing spark discharge during the execution of the fuel introduction process. However, during the execution of the fuel introduction process, the ignition device 19 may be made to perform spark discharge at a time when the air-fuel mixture does not burn in the cylinder 11. For example, when the spark discharge is performed when the piston 12 is located near the bottom dead center, the air-fuel mixture is not burned in the cylinder 11 where the spark discharge is performed. Therefore, even if spark discharge is performed during the fuel introduction process, the fuel injected from the fuel injection valve 17 can be discharged from the cylinder 11 to the exhaust passage 21 without being burned.

-The internal combustion engine to which the control device of the internal combustion engine is applied may include an in-cylinder injection valve which is a fuel injection valve for directly injecting fuel into the cylinder 11. In this case, during the execution of the fuel introduction process, the fuel may be injected into the cylinder 11 from the in-cylinder injection valve, and the fuel may be discharged to the exhaust passage 21 without being burned. As a result, unburned fuel can be introduced into the three-way catalyst 22.

-The system of the hybrid vehicle may be a system different from the system shown in FIG. 1 as long as the rotation speed of the crank shaft 14 can be controlled by driving the motor.

-The control device for an internal combustion engine may be embodied as a device for controlling an internal combustion engine mounted on a vehicle having no power source other than the internal combustion engine. Even in an internal combustion engine mounted on such a vehicle, combustion of the air-fuel mixture in the cylinder may be stopped under the condition that the crank shaft 14 is rotating due to inertia. If the execution condition of the fuel introduction process is satisfied during such a combustion stop period, the fuel introduction process will be executed.

10 ... Internal combustion engine, 11 ... Cylinder, 14 ... Crank shaft, 17 ... Fuel injection valve, 19 ... Ignition device, 21 ... Exhaust passage, 22 ... Three-way catalyst, 23 ... Particulate filter, 80 ... Air flow meter, 110 ... Internal combustion Engine control unit, 114 ... Temperature calculation unit.

Claims (1)

An air flow meter that detects the amount of intake air, a three-way catalyst that is placed in the exhaust passage and purifies the exhaust, and a patty that is placed downstream of the three-way catalyst in the exhaust passage and is included in the exhaust. It is equipped with a particulate filter that collects curate matter, and is applied to internal combustion engines that burn the air-fuel mixture containing fuel injected from the fuel injection valve in the cylinder by the spark discharge of the ignition device.
When the combustion in the cylinder is stopped under the condition that the crank shaft of the internal combustion engine is rotating, fuel is injected from the fuel injection valve, and the fuel is left unburned from the inside of the cylinder to the exhaust passage. It is a control device that executes the fuel injection process to be discharged to the internal combustion engine.
A temperature calculation unit for calculating the provisional temperature of the particulate filter at regular time intervals using the fuel injection amount from the fuel injection valve during the fuel introduction process is provided.
The temperature calculation unit calculates the current temperature of the particulate filter based on the provisional temperature of the particulate filter before a predetermined period during the fuel introduction process and within a specified period from the end of the fuel introduction process. Internal combustion engine control device.

Images