JP2020023906A - Control device for internal combustion engine - Google Patents

Abstract

To actualize temperature calculation of a particulate filter while suppressing the deviation of a calculated temperature from an actual temperature of the particulate filter.SOLUTION: An internal combustion engine control unit 110 includes a temperature calculation part 114 for calculating a temporary temperature of a particulate filter 23 at each fixed time interval using a fuel injection amount during executing fuel introduction processing for allowing fuel injected from a fuel injection valve 17 to flow out of a cylinder 11 into an exhaust passage 21 as it is unburnt in such a situation that a crank shaft 14 is rotated. During the fuel introduction processing and in a specific period after finishing the fuel introduction processing, the temperature calculation part 114 calculates the temperature of the particulate filter 23 on the basis of the temporary temperature of the particulate filter 23 before a predetermined period.SELECTED DRAWING: Figure 2

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 a fuel. A three-way catalyst for purifying exhaust gas is arranged in an exhaust passage of the internal combustion engine. A particulate filter that collects particulate matter is disposed downstream of the three-way catalyst in the exhaust passage.

  In the internal combustion engine described in Patent Literature 1, when the load applied to the internal combustion engine is low when the required torque for the internal combustion engine is reduced due to cancellation of the accelerator operation or the like, combustion in the cylinder may be stopped. is there. During this combustion stop period, a fuel introduction process for regenerating the particulate filter is performed. That is, in the fuel introduction process, fuel is injected from the fuel injection valve, and the fuel flows out of the cylinder into the exhaust passage without burning. 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 trapped in the particulate filter is burned.

US Patent Application Publication No. 2014/0041362

  In the technique disclosed in Patent Literature 1, the temperature of the particulate filter increases due to the heat stored in the three-way catalyst being transferred by the gas flowing through the three-way catalyst and flowing into the particulate filter. Then, 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 amount of fuel injected from the fuel injection valve and the like. However, when the above-described fuel introduction process is performed, a time period from when the temperature of the three-way catalyst starts to rise to a time when the high-temperature gas from the three-way catalyst reaches the particulate filter reaches a time when the heat spreads to the entire three-way catalyst. And a time delay corresponding to 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 difference may occur between the actual temperature of the particulate filter and the calculated temperature.

  A control device for an internal combustion engine for solving the above problems includes an air flow meter for detecting an intake air amount, a three-way catalyst disposed in an exhaust passage and purifying exhaust gas, and a three-way catalyst in the exhaust passage. A particulate filter disposed on the downstream side and for collecting particulate matter contained in the exhaust gas, and a fuel-fuel mixture injected from a fuel injection valve is discharged into the cylinder by spark discharge of an ignition device. When the combustion in the cylinder is stopped while the crankshaft of the internal combustion engine is rotating, the fuel is injected from the fuel injection valve, and the fuel is unburned. A control device for executing a fuel introduction process for causing the fuel to flow out of the cylinder to the exhaust passage, wherein the fuel from the fuel injection valve is supplied during the fuel introduction process. Using a fuel injection amount, a temperature calculation unit that calculates a provisional temperature of the particulate filter at regular time intervals, the temperature calculation unit during the fuel introduction process and within a specified period from the end of the fuel introduction process Calculates a current temperature of the particulate filter based on a provisional temperature of the particulate filter before a predetermined period.

  In the above configuration, the provisional temperature is calculated using the fuel injection amount during the fuel introduction process that affects the temperature of the three-way catalyst, so that the provisional temperature is the temperature of the three-way catalyst due to the fuel introduction process. Changes are reflected. Here, it takes a certain amount of time before the gas heated by the three-way catalyst reaches 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 the predetermined period on the current temperature, a time delay until the gas heated by the three-way catalyst reaches the particulate filter can be simulated. 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 a hybrid system. 1 is a schematic diagram of an internal combustion engine. 4 is a flowchart illustrating a processing procedure related to an injection valve control process. 6 is a time chart illustrating an example of a time change of an introduction processing execution flag and an introduction processing completion flag. 9 is a flowchart illustrating a processing procedure related to an upstream region temperature calculation processing. 9 is a flowchart illustrating a processing procedure related to a middle basin temperature calculation processing. 9 is a flowchart illustrating a processing procedure related to a filter temperature calculation processing. 6 is a time chart showing an example of a change over time in a catalyst upstream temperature, a catalyst middle flow temperature, and a filter temperature.

Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to the drawings.
First, it will be described a schematic configuration of a hybrid system in a hybrid vehicle.
As shown in FIG. 1, the hybrid vehicle includes an internal combustion engine 10, a power distribution integration mechanism 40 connected to the crankshaft 14 of the internal combustion engine 10, and a first motor generator connected to the power distribution integration mechanism 40. 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 integration 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 of the pinion gears 43 is supported by the carrier 44 so that the pinion gears 43 can freely rotate and revolve. The first motor generator 71 is connected to the sun gear 41. The crankshaft 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 and the ring gear 42. 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 electric power.

  On the other hand, when the first motor generator 71 functions 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. When the output torque of the first motor generator 71 is input to the crankshaft 14 via the carrier 44, the crankshaft 14 can be rotated. In the present embodiment, rotating the crankshaft 14 by driving the first motor generator 71 in this manner is referred to as “motoring”.

  The reduction gear 50 is a planetary gear mechanism, and includes 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. I have. The ring gear shaft 45 is connected to the ring gear 52. 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. Each pinion gear 53 is rotatable but non-revolvable.

  When the vehicle is decelerated, the regenerative braking force corresponding to the amount of power generated by the second motor generator 72 can be generated in the vehicle by causing the second motor generator 72 to function as a generator. When the second motor generator 72 functions 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. Is done. As a result, the drive wheels 62 can be rotated, that is, the vehicle can run.

  First motor generator 71 exchanges power with battery 77 via first inverter 75. The second motor generator 72 exchanges power with the battery 77 via the second inverter 76.

  As shown in FIG. 2, a reciprocating piston 12 is accommodated in a cylinder 11 of the internal combustion engine 10. The piston 12 is connected to a crankshaft 14 via a connecting rod 13. In the intake passage 15 of the internal combustion engine 10, an air flow meter 80 for detecting an intake air amount is arranged. Downstream of the air flow meter 80 in the intake passage 15, a throttle valve 16 for opening and closing the flow passage of the intake passage 15 is provided 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 that injects fuel into a portion of the intake passage 15 downstream of the throttle valve 16. Fuel and air are introduced into the cylinder 11 through the intake passage 15 when the intake valve 18 is open. Then, in the cylinder 11, a mixture containing the air introduced through the intake passage 15 and the fuel injected from the fuel injection valve 17 is burned by the spark discharge of the ignition device 19. The exhaust gas generated in the cylinder 11 by 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 exhaust gas and a particulate filter 23 disposed downstream of the three-way catalyst 22. The particulate filter 23 has a function of collecting particulate matter contained in exhaust gas flowing through the exhaust passage 21. An air-fuel ratio sensor 81 that detects the oxygen concentration in the gas flowing through the exhaust passage 21, that is, the air-fuel ratio of the air-fuel mixture, is disposed upstream of the three-way catalyst 22 in the exhaust passage 21.

  In the internal combustion engine 10, the combustion of the air-fuel mixture in the cylinder 11 may be stopped when the vehicle is running and the crankshaft 14 is rotating. The period during which the combustion of the air-fuel mixture in the cylinder 11 is stopped while the crankshaft 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 crankshaft 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.

  In 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 the fuel from the fuel injection valve 17 and allowing the fuel to flow out of the cylinder 11 to the exhaust passage 21 without burning. Any 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 and the amount of oxygen sufficient to burn the fuel is present in the three-way catalyst 22, the fuel is burned by the three-way catalyst 22. As a result, the temperature of the three-way catalyst 22 increases. 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 and the temperature of the particulate filter 23 becomes equal to or higher than the combustible temperature, the particulate matter collected by the particulate filter 23 is burned.

Next, a control configuration of the hybrid vehicle will be described with reference to FIGS.
As shown in FIG. 1, the control device 100 of the hybrid vehicle calculates a required torque TQR, which is a 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 the amount of operation 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 each of 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 “control device for an internal combustion engine” in the present embodiment. When the fuel introduction process is performed during the combustion stop period, the drive of the first motor generator 71 is controlled by the motor control unit 120 to perform the motoring. That is, the rotation speed of the crankshaft 14 during the combustion stop period can be controlled through the execution of the motoring.

  As shown in FIG. 2, an air-fuel ratio detection value AF, which is an air-fuel ratio detected by the air-fuel ratio sensor 81, is input to the internal combustion engine control unit 110. Further, the internal combustion engine control unit 110 receives an air amount detection value DR which is an intake air amount detected by the air flow meter 80. Further, a crank position detection value θ which is a rotation position of the crankshaft 14 detected by the crank angle sensor 82 is input to the internal combustion engine control unit 110. The detected 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 includes, as functional units, 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 a parameter related to the intake air amount. And a temperature calculation unit 114 for calculating the temperatures of the three-way catalyst 22 and the particulate filter 23.

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

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

  The air amount calculation unit 113 calculates an integrated total air amount ADR which is a cumulative value of the air amount detection values DR since the start of the internal combustion engine control unit 110. Specifically, the air amount calculation unit 113 sets the integrated total air amount ADR to “0” when the control device 100 of the hybrid vehicle starts. Then, the air amount calculation unit 113 acquires the air amount detection value DR at predetermined intervals (for example, every several milliseconds) while the control device 100 of the hybrid vehicle is running, and acquires 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 post-introduction integrated amount UDR which is a cumulative value of the air amount detection value DR from the time when the fuel introduction process ends. 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 values DR at predetermined intervals (for example, every several milliseconds) from the time when the fuel introduction process ends, and sequentially accumulates the acquired air amount detection values DR. To calculate the integrated amount UDR after introduction.

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

  The temperature calculation unit 114 performs 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 broadly divided into a process of calculating a provisional temperature of the particulate filter 23 (hereinafter referred to as a provisional filter temperature FT1) and a process of calculating the filter temperature FT.

  During execution of the fuel introduction process, the temperature calculation unit 114 performs a filter based on the catalyst middle flow 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. During the execution of the fuel combustion process, the temperature calculation unit 114 calculates the provisional filter temperature FT1 based on the operating state of the internal combustion engine 10. Further, the temperature calculation unit 114 calculates a predetermined initial value as the provisional filter temperature FT1 during execution of the fuel cut process. The temperature calculation unit 114 stores the provisional filter temperature FT1 calculated according to each process and the total air integrated amount ADR in association with each other.

  The temperature calculation unit 114 calculates the filter temperature FT during the fuel introduction process and within a specified period from the end of the fuel introduction process, based on the filter provisional temperature FT1 before a predetermined period. In the present embodiment, the specified period is determined based on the integrated amount UDR after introduction. That is, the period from the end of the fuel introduction process to the point where the post-introduction integrated amount UDR reaches the filter specified value FSP which is a predetermined specified value corresponds to the specified period. The filter specified value FSP 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 is determined based on the total air integrated amount ADR. Here, the total air accumulation amount ADR continues to increase from the start of the internal combustion engine control unit 110 to the end of the operation. Therefore, the total air accumulation amount ADR can also be regarded as a parameter representing the length of time since the start of the internal combustion engine control unit 110. For example, it is assumed that the integrated total air amount ADR has increased to “X” after the start of the internal combustion engine control unit 110. As for the filter provisional temperature FT1 calculated when the total air integrated amount ADR is smaller than X, information of a timing earlier than the timing when the total air integrated amount ADR becomes “X” is reflected. In the present embodiment, the filter temperature FT is determined based on the filter provisional temperature FT1 calculated at a stage where the total air integrated amount ADR is smaller than the current amount by a predetermined amount V, that is, at a stage before the total air integrated amount ADR by a predetermined amount V. calculate.

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

  When the injection valve control section 112 starts the injection valve control processing, it executes the processing of step S10. In step S10, the injection valve control unit 112 determines whether a condition for stopping 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 proceeds with the process to step S50. Then, the injection valve control unit 112 sets the ignition flag to ON in step S50. Further, in the following step S55, the injection valve control unit 112 sets an introduction processing execution flag, which is a flag indicating that the fuel introduction processing is being executed, to off. Thereafter, 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 a 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 detected air-fuel ratio AF becomes the target air-fuel ratio. The target air-fuel ratio is set to, for example, a stoichiometric air-fuel ratio or a value near the stoichiometric air-fuel ratio. After the processing in step S60, the injection valve control unit 112 advances the processing to step S65.

  In step S65, the injector control unit 112 controls the driving of the fuel injector 17 based on the calculated required value QPR. Then, the injection valve control unit 112 ends the series of processing once. Note that the processing in steps S50, S60, and S65 is a fuel combustion processing for burning the air-fuel mixture containing the fuel injected from the fuel injection valve 17 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 equal to or less than “0” in the determination of step S10, the injection valve control unit 112 satisfies the condition for stopping the combustion of the air-fuel mixture in the cylinder 11. Is determined (step S10: YES). And the injection valve control part 112 advances a process to step S15. Then, the injection valve control unit 112 sets the ignition flag to off, and advances the processing to step S20. While the ignition flag is set to off, the internal combustion engine 10 is in a combustion stop period.

  In step S20, the injection valve control unit 112 determines whether the execution condition of the fuel introduction process is satisfied. In this embodiment, there are two conditions for executing the fuel introduction process. One of the execution conditions is that both the catalyst upstream temperature UT and the catalyst midstream temperature MT are equal to or higher than a specified temperature. The specified temperature is set to the activation temperature of the three-way catalyst 22 or a temperature slightly higher than the activation temperature. Another one of the above-mentioned execution conditions is that the estimated value of the trapped amount of particulate matter in the particulate filter 23 is equal to or larger than the determined trapped amount. When the trapping amount increases, the pressure difference between the portion of the exhaust passage 21 between the three-way catalyst 22 and the particulate filter 23 and the portion of the exhaust passage 21 downstream of the particulate filter 23 tends to increase. Therefore, for example, an estimated value of the trapping 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 processing execution flag to off. Thereafter, the injection valve control unit 112 causes the process to proceed 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 injector control unit 112 sets the required value QPR of the fuel injection amount of the fuel injector 17 to “0”. Then, in the following step S90, the injector control unit 112 controls the driving of the fuel injector 17 based on the required value QPR. That is, in this case, no fuel is injected from the fuel injection valve 17. After executing the processing of step S90, the injection valve control unit 112 temporarily ends a series of processing. The processing in steps S15, S85, and S90 is a fuel cut processing in which combustion in the cylinder 11 is stopped while the crankshaft 14 of the internal combustion engine 10 is rotating and fuel is not introduced into the cylinder 11. It is.

  On the other hand, in step S20, when determining that both of the two execution conditions of the fuel introduction process are satisfied (step S20: YES), the injection valve control unit 112 advances the process 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 a predetermined temperature. The predetermined temperature is determined in advance by experiments or the like as a value capable of burning the particulate matter collected in the particulate filter 23 when fuel is injected from the fuel injection valve 17 in the fuel introduction process. Have been. When determining that the temperature of the particulate filter 23 is lower than the predetermined temperature (step S25: NO), the injection valve control unit 112 proceeds to step S80. In this case, the above-described fuel cut processing 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, in step S30, the injection valve control unit 112 sets the introduction process execution flag to ON. Note that the motor control unit 120 executes motoring as the process proceeds to step S30. Thereafter, the injection valve control unit 112 causes the process to proceed to step S35.

  In step S35, the injection valve control unit 112 calculates a 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. In the fuel introduction process, the fuel injection amount for causing the fuel to flow out of the cylinder 11 to the exhaust passage 21 without being burned 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. After step S35, the injection valve control unit 112 advances the process to step S40.

  In step S40, the injector control unit 112 controls the driving of the fuel injector 17 based on the calculated required value QPR. Then, the injection valve control unit 112 ends the series of processing once. Note that the processing of steps S15, S35, and S40 is performed by injecting fuel from the fuel injection valve 17 when stopping combustion in the cylinder 11 while the crankshaft 14 of the internal combustion engine 10 is rotating. This is a fuel introduction process for causing the fuel to flow out of the cylinder 11 to the exhaust passage 21 without burning.

  Note that the injection valve control unit 112 updates the value of the introduction processing completion flag, which is a flag indicating that the fuel introduction processing has been completed, while repeatedly performing the above processing. Specifically, the injection valve control unit 112 sets the introduction processing completion flag to “0” when the control device 100 of the hybrid vehicle starts. Also, the injection valve control unit 112 sets the introduction processing completion flag to “0” when the introduction processing execution flag is on. Then, when the introduction processing execution flag is turned off from on, the injection valve control unit 112 sets the introduction processing completion flag to “1”. Therefore, as shown in the example in FIG. 4, from the start of the internal combustion engine control unit 110 to the completion of the first fuel introduction process, the introduction process completion flag is “0”, and the first fuel introduction process is performed. At the time of completion, the introduction processing completion flag becomes “1”. Thereafter, the introduction processing completion flag is set to “1” during a period in which the fuel introduction processing is not executed (the fuel combustion processing or the fuel cut processing is executed), and is updated to “0” during execution of the fuel introduction processing. Is repeated.

  Next, a procedure of an upstream region temperature calculation process executed by the temperature calculation unit 114 to calculate 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 catalyst upstream initial value that is a predetermined constant when the control device 100 of the hybrid vehicle is started. Further, when the control device 100 of the hybrid vehicle starts, the temperature calculation unit 114 sets the upstream addition temperature UP, which is a correction value for the catalyst upstream temperature UT, to “0”. Further, at the time when the control device 100 of the hybrid vehicle is started, the temperature calculating unit 114 holds the holding value for reflecting the increase in the catalyst upstream temperature UT due to the fuel introduction processing to the catalyst middle flow temperature MT after the fuel introduction processing ends. Set H to “0”. Then, while the control device 100 of the hybrid vehicle is running, the temperature calculation unit 114 executes the following upstream region temperature calculation process at every predetermined control cycle (for example, every several seconds). This control cycle is longer than the cycle in which the air amount calculation unit 113 calculates the total air integrated amount ADR.

  When starting the upstream region temperature calculation process, the temperature calculation unit 114 executes the process of step S200. In step S200, temperature calculation section 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being performed. If it is determined that the ignition flag is on (step S200: YES), temperature calculating section 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 indicating the relationship among the engine speed NE, the engine load KL, and the catalyst upstream temperature UT. The temperature calculation unit 114 refers to the map for upstream of the catalyst, and is calculated based on the current engine speed NE calculated based on the detected crank position value θ, the detected crank position value θ, and the detected air amount value DR. A temperature corresponding to the current engine load KL is calculated as a first provisional temperature UT1. After step S205, temperature calculation unit 114 proceeds with the process to step S215.

  On the other hand, in step S200, when temperature calculating section 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 catalyst upstream initial value as the first provisional temperature UT1. After step S210, temperature calculating section 114 proceeds with the process to step S215.

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

Second provisional temperature UT2 = previous catalyst upstream temperature UTP + (first provisional temperature UT1-previous catalyst upstream temperature UTP) × ratio A (1)
Here, the ratio A is a positive value smaller than 1. The ratio A is determined in advance as a dedicated value for calculating the second provisional temperature UT2. As is clear from the equation (1), the second provisional temperature UT2 is obtained by calculating the difference between the first provisional temperature UT1 and the previously calculated catalyst upstream temperature UTP with respect to the previous catalyst upstream temperature UTP into the ratio A. This is reflected by the corresponding weight. After step S215, temperature calculation unit 114 proceeds with the process to step S220.

  In step S220, the temperature calculation unit 114 determines whether the introduction process execution flag is turned on, that is, whether the fuel introduction process is being executed. If temperature calculation unit 114 determines that the introduction process execution flag is ON (step S220: YES), the process proceeds 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 addition upstream map indicating 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 calculates the temperature corresponding to the current required value QPR of the fuel injection amount as the provisional addition temperature UP1 with reference to the addition upstream map. Thereafter, the temperature calculation unit 114 proceeds with 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 method of smoothing is the same as the method shown in the above equation (1). That is, the temperature calculation unit 114 calculates the upstream addition temperature UP using the following equation (2).

Upstream addition temperature UP = previous upstream addition temperature UPP + (temporary addition temperature UP1-previous upstream addition temperature UPP) × 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, temperature calculation unit 114 causes the process to proceed to step S240.

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

  In step S240, the temperature calculation unit 114 calculates a catalyst upstream temperature UT. Specifically, the temperature calculation unit 114 calculates, as the catalyst upstream temperature UT, a value obtained by adding the upstream addition temperature UP to the second provisional temperature UT2. Thereafter, the temperature calculation unit 114 proceeds with the process to step S245.

  In step S245, the temperature calculation unit 114 determines whether or not the introduction processing completion flag is “1”. If the temperature calculation unit 114 determines that the introduction processing completion flag is “1” (step S245: YES), the process proceeds to step S250. In this case, the temperature calculation unit 114 updates the previous held value HP as the current held value H. Then, the temperature calculation unit 114 ends the series of processing once.

  On the other hand, in step S245, when temperature calculating section 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 held value H to the current (latest) upstream addition temperature UP. Then, the temperature calculation unit 114 ends the series of processing once.

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

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

  Upon starting the middle basin temperature calculation process, the temperature calculation unit 114 executes the process of step S400. In step S400, temperature calculating section 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being performed. When it is determined that the ignition flag is on (step S400: YES), temperature calculating section 114 proceeds to 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 middle flow map representing the relationship among the engine speed NE, the engine load KL, and the middle catalyst temperature MT. The temperature calculation unit 114 calculates the temperature corresponding to the current engine speed NE and the engine load KL as the first provisional temperature MT1 with reference to the catalyst middle flow map. Note that 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 as the catalyst middle flow temperature MT is used as the catalyst middle flow 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 processing. After step S405, temperature calculation unit 114 proceeds with the process to step S415.

  On the other hand, in step S400, when temperature calculating section 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 the middle flow of the catalyst as the first provisional temperature MT1. As described above, the initial value for the middle flow of the catalyst is the same as the initial value for the upstream of the 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 region temperature calculation processing. After step S410, temperature calculation unit 114 causes the process to proceed to step S415.

  In step S415, the temperature calculation unit 114 calculates a 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 a smoothing process similar to step S215 of the upstream region temperature calculation process. The value of the ratio used in the smoothing process is a value dedicated to the present process (the process of step S415). After step S415, temperature calculation unit 114 causes the process to proceed to step S420.

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

  In step S425, the temperature calculation unit 114 determines whether the introduction process execution flag is turned on, that is, whether the fuel introduction process is being executed. If temperature calculation unit 114 determines that the introduction process execution flag is ON (step S425: YES), the process proceeds to step S430. Then, in step S430, temperature calculating section 114 calculates provisional additional temperature MP1. Specifically, the temperature calculation unit 114 stores an addition middle flow map that represents the relationship between the fuel injection amount from the fuel injection valve 17 and the increase in the catalyst middle flow temperature MT. In addition, the effect of increasing the temperature of the catalyst middle flow temperature MT in the upstream region of the three-way catalyst 22 due to the fuel introduction process to the middle flow region and taking the catalyst middle flow temperature MT into account is considered in the increase of the catalyst middle flow temperature MT in the addition middle flow map. Have been. The temperature calculation unit 114 calculates the temperature corresponding to the current required value QPR of the fuel injection amount as the provisional addition temperature MP1 with reference to the middle flow map. Thereafter, the temperature calculation unit 114 proceeds with the process to step S435.

  On the other hand, in step S425, if temperature calculation unit 114 determines that the introduction process execution flag is turned off (step S425: NO), the process proceeds to step S440. In step S440, the temperature calculation unit 114 determines whether the introduction processing completion flag is “1” and the post-introduction integrated amount UDR is equal to or smaller than the catalyst specified value CSP. The specified value CSP for the catalyst determines whether or not the heat generated in the upstream area of the three-way catalyst 22 due to the fuel injection in the fuel introduction processing has been transferred to the middle area of the three-way catalyst 22 using gas as a medium. It is determined 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 for increasing or decreasing the flow velocity of the gas flowing through the exhaust passage 21. It is determined based on the results. As a situation where the determination in step S440 is YES, the following situation can be considered. That is, after the fuel introduction process is completed, the heat generated in the upstream region of the three-way catalyst 22 due to the fuel injection in the fuel introduction process is not completely transferred to the middle region of the three-way catalyst 22. In such a situation, heat generated in the upstream area of the three-way catalyst 22 can be transferred to the middle area of the three-way catalyst 22 by using the gas as a medium to increase the catalyst middle temperature MT. On the other hand, the situation in which the determination in step S440 is NO indicates that the heat generated in the upstream area of the three-way catalyst 22 due to the fuel introduction processing has been completely transferred to the middle area of the three-way catalyst 22, ie, the three-way catalyst 22 In this situation, the gas flowing downstream from the catalyst 22 does not affect the catalyst middle flow temperature MT. Also, the determination in step S440 is NO from when the internal combustion engine control unit 110 is started to when the first fuel introduction process is completed.

  In step S440, the temperature calculation unit 114 determines that the introduction process completion flag is “1” and that the post-introduction integrated amount UDR is equal to or less than the catalyst specified value CSP (step S440: YES). The process proceeds to step S445. Then, in step S445, the temperature calculation unit 114 calculates the held value H as the provisional addition temperature MP1. As described above, while the introduction processing completion flag is “1”, the held value H is the upstream addition temperature UP at the last timing during the execution of the fuel introduction processing. By calculating the hold value H as the provisional addition temperature MP1, the increase in the catalyst upstream temperature UT due to the fuel introduction processing is reflected on the catalyst middle flow temperature MT through step S435 described below. After step S445, the temperature calculation unit 114 proceeds to step S435.

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

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

  In step S440, the temperature calculation unit 114 determines whether one of the determination condition that the introduction processing completion flag is “1” and the determination condition that the post-introduction integrated amount UDR is equal to or less than the catalyst specified value CSP. If 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 process proceeds to step S455, and the temperature calculation unit 114 calculates the middle catalyst flow temperature MT.

  Next, a procedure of a filter temperature calculation process executed by the temperature calculation unit 114 to calculate the filter temperature FT will be described with reference to FIG. Temperature control section 114 sets filter temperature FT to an initial value for a filter, which is a predetermined constant, when control device 100 of the hybrid vehicle is started. Then, while control device 100 of the hybrid vehicle is running, temperature calculation section 114 executes the following filter temperature calculation processing at the same control cycle as the upstream area temperature calculation processing. The temperature calculation unit 114 starts the filter temperature calculation process at the timing when the calculation of the catalyst middle flow temperature MT in the middle flow region temperature calculation process is completed.

  When starting the filter temperature calculating process, the temperature calculating unit 114 executes the process of step S500. In step S500, temperature calculation section 114 determines whether or not the ignition flag is on, that is, whether or not the fuel combustion process is being performed. If temperature calculating section 114 determines that the ignition flag is on (step S500: YES), it proceeds to step S510.

  In step S510, temperature calculating section 114 calculates filter provisional temperature FT1 based on the operating state of internal combustion engine 10. Specifically, the temperature calculation unit 114 stores a first filter map that represents a relationship among the engine speed NE, the engine load KL, and the filter temperature FT. The temperature calculation unit 114 calculates the temperature corresponding to the current engine speed NE and the engine load KL as the provisional filter temperature FT1 with reference to the first filter map. The provisional filter 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 the future time. After step S510, temperature calculation unit 114 proceeds with the process to step S550.

  On the other hand, in step S500, when the temperature calculation unit 114 determines that the ignition flag is off, the process proceeds to step S520. Then, in step S520, temperature calculating section 114 determines whether or not the introduction processing execution flag is on, that is, whether or not the fuel introduction processing is being performed. If temperature calculation unit 114 determines that the introduction process execution flag is on (step S520: YES), it proceeds to step S530.

  In step S530, the temperature calculation unit 114 calculates the filter provisional temperature FT1 based on the catalyst middle flow temperature MT calculated in the middle flow region temperature calculation process and the current air amount detection value DR. Specifically, the temperature calculation unit 114 stores a second filter map that represents a relationship among the catalyst middle flow temperature MT, the intake air amount, and the filter temperature FT. The temperature calculation unit 114 refers to the filter second map, and calculates a temperature corresponding to the catalyst middle flow temperature MT calculated by the middle flow region temperature calculation process and the current air amount detection value DR as the filter provisional temperature FT1. . Note that, as described in the midstream region temperature calculation process, the catalyst midstream temperature MT during the fuel introduction process is calculated by reflecting the midstream addition temperature MP calculated based on the fuel injection amount from the fuel injection valve 17. Is done. That is, the catalyst middle flow temperature MT during the fuel introduction process is calculated using the fuel injection amount from the fuel injection valve 17. In step S530, since the provisional filter temperature FT1 is calculated based on the middle catalyst temperature MT calculated using the fuel injection amount from the fuel injection valve 17, the provisional filter temperature FT1 is Is calculated by using the fuel injection amount of. The provisional filter 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 the future time. After step S530, temperature calculating section 114 causes the process to proceed to step S550.

  In addition, in Step S520, when it is determined 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 filter initial value as the filter provisional temperature FT1. The provisional filter 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. After step S540, temperature calculating section 114 causes the process to proceed to step S550.

  In step S550, temperature calculation section 114 stores filter provisional temperature FT1 and current total air accumulation 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 accumulation amount ADR in the time direction as provisional temperature data.

  In step S600, temperature calculation section 114 determines whether or not the introduction processing execution flag is on, that is, whether or not the fuel introduction processing is being performed. If temperature calculation unit 114 determines that the introduction process execution flag is ON (step S600: YES), the process proceeds to step S610.

  On the other hand, in step S600, if temperature calculation unit 114 determines that the introduction process execution flag is OFF (step S600: NO), the process proceeds to step S605. In step S605, the temperature calculation unit 114 determines whether the introduction processing completion flag is “1” and the post-introduction integrated amount UDR is equal to or smaller than the filter specified value FSP. The specified value FSP for the filter can determine whether or not the heat generated in, for example, the middle region of the three-way catalyst 22 along with the fuel injection in the fuel introduction process has been transferred to the particulate filter 23 using gas as a medium. Specified as a value. The filter specified value FSP 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 is, for example, an experiment for increasing or decreasing the flow velocity of the gas flowing through the exhaust passage 21. Is determined based on the result obtained by repeating the above. The following situations can be considered as the situation where the determination in step S605 is YES. That is, after the fuel introduction process is completed, the heat generated in the three-way catalyst 22 due to the fuel injection in the fuel introduction process is not completely transferred to the particulate filter 23. In such a situation, heat generated in the three-way catalyst 22 can be transferred to the particulate filter 23 using gas as a medium and raise the filter temperature FT. On the other hand, the situation in which the determination in step S605 is NO indicates that the heat generated in the three-way catalyst 22 due to the fuel introduction processing has been completely transferred to the particulate filter 23, that is, flows downstream from the three-way catalyst 22. The situation is such that the gas does not affect the filter temperature FT. Also, the determination in step S605 is NO from the start of the internal combustion engine control unit 110 to the completion of the first fuel introduction process.

  In step S605, if the temperature calculation unit 114 determines that the introduction process completion flag is “1” and that the post-introduction integrated amount UDR is equal to or smaller than the filter specified value FSP (step S605: YES), the process proceeds to step S605. Is advanced to step S610.

  In step S610, the temperature calculation unit 114 refers to the provisional temperature data created in step S550 described above, and determines the filter provisional temperature FT1 when the total integrated air amount ADR is smaller by the predetermined amount V than the current total air integrated amount ADR. Is calculated with interpolation calculation. The following method can be considered as an example of the interpolation calculation. For example, the total air accumulation amount ADR required in step S610 (the total air accumulation amount ADR when the current total air accumulation amount ADR is smaller by the predetermined amount V) is stored in the plurality of total air accumulation amounts 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 provisional filter temperature FTQ1 when the integrated total air amount ADR is “Q1” and the provisional filter temperature FTQ2 when the integrated total air amount ADR is “Q2”. A linear function that expresses 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.

  The temperature calculation unit 114 calculates the provisional filter temperature FT1 when the integrated total air amount ADR is smaller than the current integrated air amount ADR by the predetermined amount V as described above. Then, temperature calculating section 114 sets calculated filter provisional temperature FT1 to final provisional temperature FT3. Note that the timing at which the total air accumulation amount ADR is smaller than the current total air accumulation amount ADR by the predetermined amount V is earlier than the present, that is, the past. Here, the filter provisional temperature FT1 is a value for considering that the gas located upstream of the particulate filter 23 at the past timing reaches the present particulate filter 23 and affects the filter temperature FT. is there. Therefore, the predetermined amount V is determined as an amount corresponding to a time scale from which the timing at which the gas flowing downstream from the three-way catalyst 22 affects the filter temperature FT can be grasped. 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. For example, an experiment for increasing or decreasing the flow velocity of the gas flowing through the exhaust passage 21 is performed. It is determined based on the results obtained repeatedly.

  After step S610, temperature calculation unit 114 causes the process to proceed to step S615. 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 method of smoothing is the same as the method used in step S215 of the upstream region temperature calculation processing, and is performed using the following equation (3).

Filter temperature FT = previous filter temperature FTP + (final provisional temperature FT3−previous filter temperature FTP) × ratio C (3)
The value of the ratio C is a value dedicated to the present process (the process of step S615). After step S615, temperature calculating section 114 temporarily ends a series of processing.

  On the other hand, in step S605, the temperature calculation unit 114 determines whether one of the determination condition that the introduction processing completion flag is “1” and the determination condition that the post-introduction integrated amount UDR is equal to or less than the filter specified value FSP. If the condition is not satisfied (step S605: NO), the process proceeds to step S620.

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

  On the other hand, in step S620, when temperature calculating section 114 determines 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 filter initial value used in step S540 as the intermediate provisional temperature FT2. After that, the temperature calculation unit 114 proceeds to step S630.

  In step S630, temperature calculating section 114 performs a smoothing process on intermediate provisional temperature FT2 to calculate final provisional temperature FT3. The method of smoothing 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, temperature calculating section 114 proceeds to step S615 to calculate filter temperature FT. Then, the temperature calculation unit 114 ends the series of processing once.

Next, the operation and effect of the present embodiment will be described.
In the internal combustion engine 10, when the fuel is introduced into the three-way catalyst 22 during the fuel introduction process, the fuel is burned by the three-way catalyst 22, and the catalyst upstream temperature UT first increases. Thereafter, in the middle flow region of the three-way catalyst 22, the gas whose temperature has been raised in the upstream region of the three-way catalyst 22 reaches the middle flow region, and raises the catalyst middle flow temperature MT. Further, the gas heated in the middle region of the three-way catalyst 22 flows downstream through the exhaust passage 21. When the gas reaches the particulate filter 23, the temperature of the particulate filter 23 rises, and the filter temperature FT rises. As described above, in the case where the fuel introduction process is executed, the heat spreads to 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 time when 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 middle flow temperature MT, and the filter temperature FT in consideration of the amount of fuel combustion in the three-way catalyst 22 and the above-mentioned time delay. Specifically, in the upstream region temperature calculation process, when the fuel introduction process is being performed, the fuel is burned in the upstream region of the three-way catalyst 22 with the fuel injection, and the catalyst upstream temperature is calculated. In consideration of the rise in UT, the upstream addition temperature UP is calculated based on the fuel injection amount (steps S225 and S230). Then, the temperature calculation unit 114 reflects the upstream addition temperature UP on the catalyst upstream temperature UT (Step S240). Therefore, as shown in FIG. 8, if the fuel introduction process is performed between time t1 and time t2 after the control device 100 of the hybrid vehicle is started, the temperature calculation unit 114 may temporarily perform the fuel introduction process during the same period. Is calculated, a catalyst upstream temperature UT (see a solid line in FIG. 8) is calculated which is higher than a temporary catalyst upstream temperature UTX (see a dashed line in FIG. 8) calculated when it is assumed that the fuel cut process is performed.

  In the midstream region temperature calculation process, when the fuel introduction process is being performed, the fuel is burned in the middle region of the three-way catalyst 22 with the fuel injection in the fuel introduction process, and Taking into account that the temperature MT rises and that the gas heated up in the upstream region of the three-way catalyst 22 reaches the middle flow region, the middle flow addition 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 the intermediate flow addition temperature MP on the catalyst intermediate flow temperature MT (step S455). Therefore, as shown in FIG. 8, the middle catalyst 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 changed during the fuel cut process Is higher than the temporary catalyst middle flow temperature MTX (see the dashed line in FIG. 8) calculated when it is assumed that is executed.

  Further, in the middle-stream region temperature calculation process, after the fuel introduction process is completed, while the post-introduction integrated amount UDR is equal to or less than the catalyst specified value CSP (step S440: YES), the temperature calculation unit 114 sets the three-way catalyst 22 In consideration of the fact that the gas heated in the upstream region flows into the middle flow region, the middle flow 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 middle flow 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 the intermediate flow addition temperature MP on the catalyst intermediate flow temperature MT (step S455). The resulting catalyst midstream temperature MT is the catalyst midstream temperature MT at the end of the fuel introduction process (the fuel combustion in the middle region of the three-way catalyst 22, and the flow from the upstream of the three-way catalyst 22 during the fuel introduction process). (A temperature in consideration of gas inflow)) is further added with a rise in the catalyst upstream temperature UT. Therefore, during the period from time t2 when the fuel introduction process ends to time t3 thereafter, the catalyst middle flow temperature MT calculated by the temperature calculation unit 114 (see the solid line in FIG. 8) indicates that the fuel cut process was executed during the same period. Not only the temporary catalyst middle flow temperature MTX (see the dashed line in FIG. 8) calculated assuming this case, but also becomes higher than the middle catalyst temperature MT during execution of the fuel introduction process (from time t1 to time t2).

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

  Then, during the fuel introduction process (step S600: YES) and after the end of the fuel introduction process, the temperature calculation unit 114 determines that the post-introduction integrated amount UDR is equal to or less than the filter specified value FSP (step S605: YES). ) Specifies the timing at which the total air accumulation amount ADR is smaller than the current total air accumulation amount ADR by the predetermined amount V, that is, the provisional filter temperature FT1 at the past timing (step S610). Then, temperature calculating section 114 calculates filter temperature FT based on the provisional filter temperature FT1 (step S615). Here, it is assumed that the total air integration amount at an arbitrary time TX is “Z”. The gas that reaches the particulate filter 23 at this arbitrary time TX is located in the middle region of the three-way catalyst 22 at the time TXa (the total air integration amount is “Zw”) before the time TX. ing. That is, when calculating the filter temperature FT at an arbitrary time TX, the temperature TXa (total air integration amount) is used to reflect the temperature in the middle region of the three-way catalyst 22 located upstream of the particulate filter 23. May be used for calculating the filter temperature FT at an arbitrary time TX. This makes it possible to simulate a time delay until the gas flowing from the upstream side of the particulate filter 23 reaches the particulate filter 23. In this embodiment, the filter provisional temperature FT1 at the timing when the total air accumulation amount ADR is smaller by the predetermined amount V than the current total air accumulation amount ADR is reflected on the filter temperature FT. Therefore, according to the filter temperature calculation process of the present embodiment, the temperature calculation unit 114 determines 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, during the execution of the fuel introduction process and after the end of the fuel introduction process, the combustion of fuel in the middle region of the three-way catalyst 22 and the flow of gas from the upstream region of the three-way catalyst 22 are performed. Is reflected in the filter temperature FT. From this, as shown in FIG. 8, the temperature calculation unit 114 is provided between the time t1 and the time t2 when the fuel introduction process is executed, and between the time t2 when the fuel introduction process is completed and a time t4 thereafter. Is higher than the tentative filter temperature FTX (see the dashed line in FIG. 8) calculated when it is assumed that the fuel cut process has been executed during the same period. In particular, the filter temperature FT becomes considerably higher than the temporary filter temperature FTX at a time later than the time t2 at which the fuel introduction processing ends, as the catalyst middle flow temperature MT becomes higher. Moreover, in the filter temperature calculation processing, a time delay until the gas heated by the three-way catalyst 22 reaches the particulate filter 23 is considered, so that the filter temperature FT peaks after the fuel introduction processing ends. Is later than the time when the catalyst middle flow temperature MT reaches a peak.

  As described above, in the present embodiment, a 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.

The present embodiment can be implemented with the following modifications. The present embodiment and the following modifications 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 processing of the above-described embodiment, the total air accumulation amount ADR is used to reflect the filter provisional temperature FT1 a predetermined period before the filter temperature FT. However, in reflecting the filter provisional temperature FT1 before the predetermined period to the filter temperature FT, it is not always necessary to use the total air accumulation amount ADR, and it is necessary to specify a predetermined period before the timing for calculating the filter temperature FT. Parameter that can be used. For example, each time the fuel introduction process is started, the air amount calculation unit 113 calculates the accumulated value of the detected air amount DR from the time when the fuel introduction process is started. Then, in step S550, temperature calculating section 114 creates provisional temperature data in which the above-described accumulated value is associated with provisional filter 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 by a predetermined amount than the current value to the provisional temperature data. Calculated based on Suppose that the timing at which the cumulative value of the air amount detection value DR from the time when the fuel introduction process is started is smaller by a predetermined amount than the current value is the timing before the fuel introduction process is started, and the provisional temperature If there is no corresponding data in the data, for example, the filter provisional temperature FT1 at the time when the fuel introduction process is started, that is, when the accumulated value is 0 may be reflected in the filter temperature FT.

  In the filter temperature calculation processing of the above embodiment, the predetermined period for reflecting the filter provisional temperature FT1 before the predetermined period with respect to the filter temperature FT is determined by the intake air amount (the predetermined amount V). This predetermined period may be determined by time. For example, in a situation where the fluctuation of the intake air amount is not so large, based on the distance and the volume from the center of the three-way catalyst 22 to the upstream end of the particulate filter 23, gas flows from the middle region of the three-way catalyst 22. The time required to reach the particulate filter 23 can be estimated. The predetermined period may be determined 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 or the time from the time when the fuel introduction process is started and the provisional filter temperature FT1 are determined. Preliminary temperature data may be created in association with the filter, and the filter temporary temperature FT1 before a predetermined period may be calculated in step S610 based on the temporary temperature data.

  In the filter temperature calculation process of the above embodiment, the specified period for determining whether or not the heat generated due to the fuel introduction process has been transferred from the middle region of the three-way catalyst 22 to the particulate filter 23 is It was determined by the amount of intake air (filter specified value FSP). However, the prescribed period may be determined by time. For example, as described in the above-described modification, in a situation where the fluctuation of the intake air amount is not so large, based on the distance and the volume from the center of the three-way catalyst 22 to the upstream end of the particulate filter 23, the gas is discharged. The time from the middle region of the three-way catalyst 22 to the particulate filter 23 can be estimated. The specified period may be determined 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 by the temperature calculation unit 114 as the initial value of the filter temperature FT when the control device 100 of the hybrid vehicle starts. 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 processing, the map used in step S510 and step S625, the map used in step S530, and the initial value used in step S540 and step S635 are changed to those corresponding to the catalyst upstream temperature UT. do it. Also, the filter specified value FSP 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 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 middle flow temperature MT.

  The method of calculating the filter temperature FT is not limited to the method following the processing procedure of the filter temperature calculation processing of the above embodiment. The filter temperature FT may not be calculated based on the catalyst upstream temperature UT or the catalyst middle flow temperature MT. That is, the temperature calculation unit 114 calculates the filter provisional temperature FT1 at regular intervals using the fuel injection amount from the fuel injection valve 17 in the fuel introduction process without calculating the catalyst upstream temperature UT or the catalyst middle flow temperature MT. calculate. At this time, if the influence of changes in the catalyst upstream temperature UT and the catalyst middle flow temperature MT is reflected in the provisional filter temperature FT1, an appropriate temperature is calculated as the provisional filter temperature FT1. Specifically, the temperature calculation unit 114 uses the fuel injection amount from the fuel injection valve 17, instead of the temperature of the three-way catalyst 22, the heat is stored in the three-way catalyst 22 and then transmitted to the particulate filter 23. Calculate the index value of the calorific value. If the provisional filter temperature FT1 is calculated based on this, it is not necessary to calculate the catalyst upstream temperature UT or the catalyst middle flow temperature MT.

  -The processing content of the middle basin temperature calculation processing can be changed. In the midstream region temperature calculation process of the above embodiment, the period for determining whether or not the gas heated during the fuel introduction process has finished reaching the middle region from the upstream region of the three-way catalyst 22 is the intake air. It was determined by the amount (specific value CSP for catalyst). However, the above period may be determined by time. For example, in a situation where the fluctuation of the intake air amount is not so large, based on the distance and the volume from the upstream end to the center of the three-way catalyst 22, the gas flows from the upstream area of the three-way catalyst 22 to the middle flow area. Can be estimated. The above period may be determined based on this time.

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

  The middle-range temperature calculation process of the above embodiment may be partially modified to be applied as a process for calculating the temperature in the downstream region 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 respectively assigned to the three-way catalyst 22. What is necessary is just to change to the thing only for the downstream area. In step S445, the amount of increase in the catalyst upstream temperature UT in the fuel introduction process may be appropriately adjusted to be used as the provisional addition temperature, or the amount of increase in the catalyst middle flow temperature MT in the fuel introduction process may be appropriately adjusted to provide the provisional addition temperature. It may be used for.

  When calculating the temperature in the downstream region of the three-way catalyst 22 as in the above-described modification, the temperature may be used for calculating the filter temperature FT. In this case, for example, in the filter temperature calculation processing, the map used in step S510 and step S625, the map used in step S530, and the initial value used in step S540 and step S635 are set to the temperature in the downstream region of the three-way catalyst 22. What is necessary is just to change to the thing corresponding. Also, the filter specified value FSP 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 values corresponding to the downstream region of the three-way catalyst 22. You can change it.

  -The processing content of the upstream area temperature calculation processing can be changed. The contents of the catalyst upstream map used in step S205 may be different from the contents of the catalyst middle flow map used in step S405 of the middle flow region temperature calculation process. The initial value for the upstream of the catalyst used in step S210 may be different from the initial value for the middle flow of the catalyst used in step S410 of the midstream region temperature calculation process. The catalyst upstream initial value 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 starts. The value that the temperature calculation unit 114 sets as the initial value of the catalyst upstream temperature UT when the control device 100 of the hybrid vehicle starts is determined by the temperature calculation unit 114 when the control device 100 of the hybrid vehicle starts. It may be different from the value set as the initial value of MT.

  In the above-described embodiment, the ignition device 19 is prevented from performing the 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 caused to perform spark discharge at a time when the air-fuel mixture does not burn in the cylinder 11. For example, when 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 has been performed. Therefore, during the fuel introduction process, even if spark discharge is performed, the fuel injected from the fuel injection valve 17 can flow out of the cylinder 11 to the exhaust passage 21 without burning.

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

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

  The control device of the internal combustion engine may be embodied as a device that controls an internal combustion engine mounted on a vehicle having no power source other than the internal combustion engine. Even in such an internal combustion engine mounted on a vehicle, combustion of the air-fuel mixture in the cylinder may be stopped while the crankshaft 14 is rotating by inertia. If the conditions for executing the fuel introduction process are satisfied during such a combustion stop period, the fuel introduction process is executed.

Reference Signs List 10 internal combustion engine, 11 cylinder, 14 crankshaft, 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 calculating unit.

Claims (1)

An air flow meter for detecting an intake air amount, a three-way catalyst disposed in the exhaust passage and purifying exhaust gas, and a three-way catalyst disposed downstream of the three-way catalyst in the exhaust passage and included in the exhaust gas. A particulate filter that collects curable matter is applied to an internal combustion engine that burns a mixture containing fuel injected from a fuel injection valve in a cylinder by spark discharge of an ignition device,
When stopping combustion in the cylinder while the crankshaft of the internal combustion engine is rotating, fuel is injected from the fuel injection valve, and the exhaust passage from the cylinder is left unburned from the fuel. A control device for performing a fuel introduction process to be discharged to the
During the fuel introduction process, using a fuel injection amount from the fuel injection valve, a temperature calculation unit that calculates a temporary temperature of the particulate filter at regular time intervals,
The temperature calculating 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. Control device for internal combustion engine.