Vehicle control device

Abstract

To improve the frequency of filter regeneration.SOLUTION: A vehicle comprises an internal combustion engine and a fluid coupling. The internal combustion engine comprises a cylinder, a fuel injection valve, a filter, and a crankshaft. The fluid coupling has a lock-up clutch, and transmits power from the crankshaft to drive wheels via the lock-up clutch. A vehicle control device executes fuel cut processing to regenerate the filter by engaging the lock-up clutch and stopping the supply of fuel from the fuel injection valve to the cylinder, on the necessary condition that a vehicle speed is equal to or greater than a permitted vehicle speed. The control device executes selection processing to select one of a manual driving mode and an automatic driving mode. When the automatic driving mode is selected, the control device executes setting processing to set a lower permitted vehicle speed compared to that when the manual driving mode is selected (S22).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle.

Background Art

[0002] The vehicle of Patent Document 1 includes an internal combustion engine and a fluid coupling. The internal combustion engine includes a cylinder, a fuel injection valve, an exhaust passage, a three-way catalyst, a filter, and a crankshaft. The cylinder is a space for burning fuel. The fuel injection valve supplies fuel into the cylinder. The exhaust passage is connected to the cylinder. The three-way catalyst is located in the exhaust passage. The three-way catalyst purifies the exhaust flowing through the exhaust passage. The filter is located on the downstream side of the three-way catalyst in the exhaust passage. The filter collects particulate matter contained in the exhaust. The crankshaft rotates based on the combustion of fuel in the cylinder. The fluid coupling includes a lock-up clutch. The lock-up clutch transmits the power from the crankshaft to the drive wheels of the vehicle.

[0003] The vehicle of Patent Document 1 includes a control device. The control device executes a fuel cut process to regenerate the filter. Specifically, the control device engages the lock-up clutch in the fuel cut process when the vehicle is running. Further, the control device stops the supply of fuel from the fuel injection valve to the cylinder in the fuel cut process. By this fuel cut process, air is supplied to the filter through the cylinder and the exhaust passage. As a result, the particulate matter of the filter burns and the filter is regenerated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a vehicle such as Patent Document 1, when the vehicle is about to stop during engagement of the lock-up clutch, it is necessary to release the lock-up clutch. This is because if the rotational speed of the crankshaft drops excessively due to the lock-up clutch being engaged, engine stall will occur. On the other hand, when releasing the lock-up clutch, a certain period of time is required to complete the release. Considering the period required for releasing the lock-up clutch in this way, it is effective to include, as an execution condition for the fuel cut process, the requirement that the vehicle speed is equal to or higher than a predetermined permitted vehicle speed. However, if the permitted vehicle speed becomes excessively high, the execution frequency of the fuel cut process will decrease. That is, there is a possibility that the regeneration frequency of the filter will decrease.

Means for Solving the Problem

[0006] A vehicle control device for solving the above problems is applied to a vehicle equipped with an internal combustion engine having a cylinder which is a space for burning fuel, a fuel injection valve for supplying fuel into the cylinder, an exhaust passage connected to the cylinder, a three-way catalyst located in the exhaust passage for purifying exhaust gas, a filter located downstream of the three-way catalyst in the exhaust passage for collecting particulate matter contained in the exhaust gas, and a crankshaft that rotates based on the combustion of fuel in the cylinder, and a fluid coupling having a lock-up clutch for transmitting power from the crankshaft to the drive wheels via the lock-up clutch. The vehicle is capable of executing a fuel cut process for regenerating the filter by stopping the supply of fuel from the fuel injection valve to the cylinder while engaging the lock-up clutch, with the requirement that the vehicle speed, which is the speed of the vehicle, is equal to or higher than a predetermined permitted vehicle speed; a release process for releasing the lock-up clutch with the requirement that the vehicle speed is less than the permitted vehicle speed; a selection process for selecting one of a manual driving mode for driving the vehicle according to the operation of the vehicle driver and an automatic driving mode for driving the vehicle in place of the driver's operation; and a setting process for setting a lower permitted vehicle speed when the automatic driving mode is selected compared to when the manual driving mode is selected.

Advantages of the Invention

[0007] Generally, when the automatic driving mode is selected, the deceleration of the vehicle tends to be less likely to increase compared to when the manual driving mode is selected. Therefore, when the automatic driving mode is selected, the period from when the vehicle starts to stop until it stops tends to be longer than when the manual driving mode is selected. In other words, when the automatic driving mode is selected, the period from when the lock-up clutch starts to operate until the vehicle stops tends to be longer. Therefore, even if the permitted vehicle speed is low when the automatic driving mode is selected, it is possible to release the lock-up clutch before stopping. According to the above configuration, when the automatic driving mode is selected, the permitted vehicle speed is lower than when the manual driving mode is selected. In this way, when the automatic driving mode is selected, the permitted vehicle speed is lowered, so that the execution frequency of the fuel cut process is increased when the automatic driving mode is selected. As a result, the regeneration frequency of the filter can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0009] <Schematic Configuration of Vehicle> Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. First, the schematic configuration of the vehicle 100 will be described.

[0010] As shown in FIG. 1, the vehicle 100 includes an internal combustion engine 10 and a motor generator 30. The internal combustion engine 10 functions as a drive source of the vehicle 100. An example of the fuel of the internal combustion engine 10 is gasoline. The motor generator 30 functions as a drive source of the vehicle 100. Therefore, the vehicle 100 is a so-called hybrid vehicle.

[0011] As shown in FIG. 2, the internal combustion engine 10 includes a plurality of cylinders 11, an intake passage 12, and an exhaust passage 13. The internal combustion engine 10 also includes a plurality of pistons 16, a plurality of connecting rods 17, a crankshaft 18, a plurality of intake valves 21, and a plurality of exhaust valves 22. The cylinder 11 is a space for burning a mixture of fuel and intake air. In the present embodiment, the internal combustion engine 10 includes four cylinders 11. Note that in FIG. 2, only one cylinder 11 is shown representatively.

[0012] The piston 16 is located inside the cylinder 11. The piston 16 is connected to the crankshaft 18 via the connecting rod 17. The piston 16 reciprocates inside the cylinder 11 when the mixture of fuel and intake air burns in the cylinder 11. Then, the crankshaft 18 rotates due to the reciprocating motion of the piston 16. That is, the crankshaft 18 rotates based on the combustion of fuel in the cylinder 11.

[0013] The intake passage 12 is connected to the cylinder 11. The intake passage 12 supplies intake air from the outside of the internal combustion engine 10 to each cylinder 11. The exhaust passage 13 is connected to the cylinder 11. The exhaust passage 13 discharges exhaust gas from each cylinder 11 to the outside of the internal combustion engine 10. The intake valve 21 is located at the downstream end of the intake passage 12. The intake valve 21 opens and closes the downstream end of the intake passage 12 by power from a valve operating mechanism (not shown). The exhaust valve 22 is located at the upstream end of the exhaust passage 13. The exhaust valve 22 opens and closes the upstream end of the exhaust passage 13 by power from a valve operating mechanism (not shown).

[0014] The internal combustion engine 10 includes a throttle valve 23, a plurality of ignition devices 24, a plurality of port injection valves 26, and a plurality of in-cylinder injection valves 27. The internal combustion engine 10 also includes a three-way catalyst 28 and a filter 29. The throttle valve 23 is located midway through the intake passage 12. The throttle valve 23 adjusts the amount of intake air flowing through the intake passage 12.

[0015] The tip of the port injection valve 26 is located in the intake passage 12 near the cylinder 11. The port injection valve 26 injects fuel into the intake passage 12, thereby supplying fuel into the cylinder 11 via the intake passage 12. The internal combustion engine 10 is equipped with four port injection valves 26 corresponding to the four cylinders 11.

[0016] The tip of the in-cylinder injection valve 27 is located inside the cylinder 11. The in-cylinder injection valve 27 supplies fuel to the cylinder 11 by injecting fuel into the cylinder 11. The internal combustion engine 10 is provided with four in-cylinder injection valves 27 corresponding to the four cylinders 11. In this embodiment, each of the port injection valve 26 and the in-cylinder injection valve 27 corresponds to a fuel injection valve.

[0017] The tip of the ignition device 24 is located inside the cylinder 11. The ignition device 24 ignites a mixture of fuel and intake air by spark discharge. The internal combustion engine 10 is provided with four ignition devices 24 corresponding to the four cylinders 11.

[0018] The three-way catalyst 28 is located midway within the exhaust passage 13. The three-way catalyst 28 purifies the exhaust gas flowing through the exhaust passage 13. Specifically, the three-way catalyst 28 purifies hydrocarbons, carbon monoxide, and nitrogen oxides from the exhaust gas. The filter 29 is located downstream of the three-way catalyst 28 within the exhaust passage 13. The filter 29 collects particulate matter contained in the exhaust gas flowing through the exhaust passage 13.

[0019] As shown in FIG. 1, the vehicle 100 includes a power transmission device 40, a differential 51, and a plurality of drive wheels 52. The power transmission device 40 includes a case 41, a damper 42, a connecting shaft 43, a clutch 44, a torque converter 45, and an automatic transmission 46. The case 41 houses the damper 42, the connecting shaft 43, the clutch 44, the torque converter 45, and the automatic transmission 46 in addition to the above-described motor generator 30. The motor generator 30 includes a rotor 31 and a stator 32. The stator 32 is fixed to the case 41. The rotor 31 is rotatable with respect to the stator 32.

[0020] The first end of the connecting shaft 43 is connected to the crankshaft 18 of the internal combustion engine 10 via the damper 42. The damper 42 suppresses fluctuations in the torque of the crankshaft 18 and transmits the power from the crankshaft 18 to the connecting shaft 43. The second end of the connecting shaft 43 is connected to the rotor 31 of the motor generator 30 via the clutch 44. The connection state of the clutch 44 can be switched between an engaged state and a released state according to the pressure of the oil supplied to the clutch 44.

[0021] The torque converter 45 includes an input shaft 45A, an output shaft 45B, a lock-up clutch 45C, a pump impeller 45D, and a turbine impeller 45E. The input shaft 45A is connected to the rotor 31 of the motor generator 30. The pump impeller 45D is connected to the input shaft 45A. Therefore, the pump impeller 45D rotates when the input shaft 45A rotates. When the pump impeller 45D rotates, power is transmitted to the turbine impeller 45E via a fluid, causing the turbine impeller 45E to rotate. The turbine impeller 45E is connected to the output shaft 45B. The lock-up clutch 45C can connect the input shaft 45A and the output shaft 45B. The output shaft 45B is connected to the automatic transmission 46. In the present embodiment, the torque converter 45 can transmit the power from the crankshaft 18 of the internal combustion engine 10 to the drive wheels 52 via the automatic transmission 46 or the like. In other words, the lock-up clutch 45C of the torque converter 45 can transmit the power from the crankshaft 18 to the drive wheels 52. Note that the torque converter 45 is an example of a fluid coupling.

[0022] The connection state of the lock-up clutch 45C is switched to either the engaged state or the released state according to the pressure of the oil supplied to the lock-up clutch 45C. Here, the engaged state means a state in which torque can be transmitted between the input shaft 45A and the output shaft 45B via the lock-up clutch 45C. The released state means a state in which torque cannot be transmitted between the input shaft 45A and the output shaft 45B via the lock-up clutch 45C.

[0023] The automatic transmission 46 includes an input shaft 46A and an output shaft 46B. The input shaft 46A is connected to the output shaft 45B of the torque converter 45. The input shaft 46A is connected to the output shaft 46B via a clutch and gears (not shown). The automatic transmission 46 can change the gear ratio. Here, the gear ratio is a ratio indicating the number of rotations of the input shaft 46A when the output shaft 46B makes one rotation. Therefore, the higher the gear ratio, the higher the rotational speed of the input shaft 46A with respect to the output shaft 46B. An example of the automatic transmission 46 is a stepped automatic transmission. The output shaft 46B is connected to the drive wheels 52 via a differential 51. The differential 51 allows a rotational speed difference to occur between the left and right drive wheels 52.

[0024] As shown in FIG. 1, the vehicle 100 includes a hydraulic device 55. The hydraulic device 55 controls the gear ratio of the automatic transmission 46 by adjusting the pressure of the oil supplied to the automatic transmission 46. Further, the hydraulic device 55 controls the connection state of the lock-up clutch 45C of the torque converter 45 by adjusting the pressure of the oil supplied to the torque converter 45. Furthermore, the hydraulic device 55 controls the connection state of the clutch 44 by adjusting the pressure of the oil supplied to the clutch 44.

[0025] As shown in FIG. 1, the vehicle 100 includes an inverter 56 and a battery 57. The battery 57 is a secondary battery. The inverter 56 adjusts the amount of power transfer between the motor generator 30 and the battery 57.

[0026] 1, the vehicle 100 is equipped with a braking device 61. The braking device 61 is a so-called mechanical braking device that mechanically brakes the wheels of the vehicle 100. In this embodiment, an example of the braking device 61 is a disc brake.

[0027] 1, the vehicle 100 is equipped with an accelerator operation amount sensor 81, a vehicle speed sensor 82, and a crank angle sensor 83. The vehicle 100 is also equipped with an air flow meter 84, an oil temperature sensor 85, and an inter-vehicle distance sensor 86. The vehicle 100 is also equipped with a brake operation amount sensor 87, a GNSS receiver 88, and a changeover switch 89.

[0028] The accelerator operation amount sensor 81 detects an accelerator operation amount ACC, which is an operation amount of an accelerator pedal (not shown) operated by the driver of the vehicle 100. The vehicle speed sensor 82 detects a vehicle speed SP, which is the speed of the vehicle 100. The crank angle sensor 83 detects a crank angle SC, which is the angular position of the crankshaft 18.

[0029] The air flow meter 84 detects the intake air amount GA, which is the amount of intake air flowing through the intake passage 12 per unit time. The oil temperature sensor 85 detects the oil temperature TA, which is the temperature of the oil supplied to the torque converter 45. In this embodiment, the oil temperature TA corresponds to the temperature of the oil that operates the lock-up clutch 45C. The inter-vehicle distance sensor 86 detects the inter-vehicle distance DV, which is the distance from the vehicle 100 to a preceding vehicle traveling ahead of the vehicle 100. An example of the inter-vehicle distance sensor 86 is a LIDAR. Note that "LIDAR" is an abbreviation for Laser Imaging Detection and Ranging.

[0030] The brake operation amount sensor 87 detects the brake operation amount BRA, which is the operation amount of a brake pedal (not shown) operated by the driver of the vehicle 100. The GNSS receiver 88 detects the position coordinates PC, which are the coordinates of the location where the vehicle 100 is located, through communication with a GNSS satellite (not shown). Note that "GNSS" is an abbreviation for Global Navigation Satellite System. The changeover switch 89 is a switch for the driver of the vehicle 100 to switch the driving mode of the vehicle 100. The driving mode of the vehicle 100 will be described later.

[0031] As shown in FIG. 1, the vehicle 100 includes a control device 90. The control device 90 acquires various information from the accelerator operation amount sensor 81, the vehicle speed sensor 82, and the crank angle sensor 83. Further, the control device 90 acquires various information from the air flow meter 84, the oil temperature sensor 85, and the inter-vehicle distance sensor 86. The control device 90 acquires various information from the brake operation amount sensor 87, the GNSS receiver 88, and the changeover switch 89.

[0032] The control device 90 includes an execution device 91, a storage device 92, and a communication device 93. An example of the execution device 91 is a CPU. The storage device 92 includes a ROM that can only be read, a volatile RAM that can be read and written, and a non-volatile storage that can be read and written. The storage device 92 stores various programs and various data in advance. Specifically, the storage device 92 stores a control program 92A in advance as one of the various programs. The execution device 91 executes various processes described later by executing the control program 92A stored in the storage device 92. Further, the execution device 91 can perform wireless communication with devices outside the vehicle 100 via the communication device 93. As a result, the execution device 91 can acquire, for example, traffic jam information on the road via the communication device 93. Note that an example of a device outside the vehicle 100 is a so-called server.

[0033] The execution device 91 calculates a vehicle required driving force, which is a required value of the driving force necessary for the vehicle 100 to travel, based on the accelerator operation amount ACC and the vehicle speed SP. The execution device 91 determines the torque distribution between the internal combustion engine 10 and the motor generator 30 based on the vehicle required driving force. The execution device 91 controls the output of the internal combustion engine 10, the power running and regeneration of the motor generator 30 based on the torque distribution between the internal combustion engine 10 and the motor generator 30. Specifically, the execution device 91 controls the internal combustion engine 10 by outputting a control signal to the internal combustion engine 10. Further, the execution device 91 controls the motor generator 30 via the inverter 56 by outputting a control signal to the inverter 56.

[0034] The execution device 91 controls the connection state of the clutch 44 via the hydraulic device 55 by outputting a control signal to the hydraulic device 55. Further, the execution device 91 controls the connection state of the lock-up clutch 45C of the torque converter 45 via the hydraulic device 55 by outputting a control signal to the hydraulic device 55. The execution device 91 controls the gear ratio of the automatic transmission 46 via the hydraulic device 55 by outputting a control signal to the hydraulic device 55. Further, the execution device 91 controls the brake device 61 by outputting a control signal to the brake device 61.

[0035] The execution device 91 executes a selection process to select a driving mode of the vehicle 100. Specifically, the execution device 91 selects one of the manual driving mode and the automatic driving mode in response to the operation of the selector switch 89 by the driver of the vehicle 100. Here, the manual driving mode is a driving mode in which the vehicle 100 is driven in response to the operation of the driver of the vehicle 100. Therefore, when the execution device 91 selects the manual driving mode, the execution device 91 drives the vehicle 100 by controlling the vehicle 100 in response to the operation of the accelerator pedal, etc., by the driver of the vehicle 100. On the other hand, the automatic driving mode is a driving mode in which the vehicle 100 is driven in place of the operation of the driver of the vehicle 100. Therefore, when the execution device 91 selects the automatic driving mode, the execution device 91 drives the vehicle 100 by controlling the vehicle 100 even when the driver of the vehicle 100 is not operating the accelerator pedal, etc.

[0036] The execution device 91 executes a release process to release the lock-up clutch 45C, with the necessary condition that the vehicle speed SP is less than a predetermined permitted vehicle speed Z. Specifically, when the automatic driving mode is selected, the execution device 91 executes the release process to release the lock-up clutch 45C when the vehicle speed SP is less than the predetermined permitted vehicle speed Z. On the other hand, when the manual driving mode is selected, the execution device 91 executes the release process to release the lock-up clutch 45C when the vehicle speed SP is less than the predetermined permitted vehicle speed Z and the braking device 61 is operating. In other words, when the manual driving mode is selected, the execution device 91 executes the release process after the vehicle speed SP is less than the predetermined permitted vehicle speed Z and the braking device 61 is operated by the driver of the vehicle 100 operating the brake pedal. The permitted vehicle speed Z is set by setting control, which will be described later.

[0037] The execution unit 91 calculates the engine speed NE, which is the rotation speed of the crankshaft 18, based on the crank angle SC. The execution unit 91 also calculates the engine load factor KL based on the engine speed NE and the intake air amount GA. Here, the engine load factor KL represents the ratio of the current cylinder inflow air amount to the cylinder inflow air amount when the internal combustion engine 10 is operated steadily at the current engine speed NE with the throttle valve 23 fully open. The cylinder inflow air amount is the amount of intake air flowing into each cylinder 11 during the intake stroke.

[0038] The execution unit 91 calculates a catalyst temperature TSC, which is the temperature of the three-way catalyst 28, based on the operating conditions of the internal combustion engine 10, such as the intake air charging efficiency and the engine rotation speed NE. The intake air charging efficiency is a value obtained by dividing the mass of intake air actually introduced into the cylinder 11 from the intake passage 12 by the mass of intake air that can be introduced into the cylinder 11 under standard atmospheric conditions. The execution unit 91 also calculates a filter temperature TF, which is the temperature of the filter 29, based on the operating conditions of the internal combustion engine 10, such as the intake air charging efficiency and the engine rotation speed NE. The execution unit 91 calculates the amount of particulate matter deposited on the filter 29 per unit time based on the engine rotation speed NE, the engine load factor KL, and the filter temperature TF. The execution unit 91 then calculates a PM deposition amount PS, which is the amount of particulate matter deposited on the filter 29, by integrating the amount of particulate matter deposited on the filter 29 per unit time.

[0039] <Settings Control> Next, the setting control executed by the control device 90 will be described with reference to Fig. 3. This setting control is a control for setting an allowed vehicle speed Z used in fuel cut control, etc., which will be described later. In this embodiment, the execution device 91 of the control device 90 starts the setting control at each predetermined control cycle.

[0040] As shown in FIG. 3, when the execution device 91 of the control device 90 starts the setting control, it executes the process of step S11. In step S11, the execution device 91 determines whether the manual driving mode is selected as the driving mode of the vehicle 100. In step S11, if the execution device 91 determines that the manual driving mode is selected as the driving mode of the vehicle 100 (S11: YES), the execution device 91 advances the process to step S21.

[0041] In step S21, the execution device 91 sets the permitted vehicle speed Z based on a predetermined first reference vehicle speed A. Specifically, first, when setting the permitted vehicle speed Z, the execution device 91 specifies a correction coefficient K. At this time, the higher the oil temperature TA, the smaller the correction coefficient K specified by the execution device 91. Further, when the inter-vehicle distance DV is greater than a predetermined fixed distance, the execution device 91 specifies a smaller correction coefficient K than when the inter-vehicle distance DV is less than or equal to the predetermined fixed distance. In other words, when no preceding vehicle is traveling in a specific area defined in advance as an area from the vehicle 100 to a certain distance in front of the vehicle 100, the execution device 91 specifies a smaller correction coefficient K than when a preceding vehicle is traveling in the specific area. An example of the above-mentioned fixed distance is about ten to several tens of meters. Furthermore, the execution device 91 determines whether or not a traffic jam has occurred within a predetermined specified area for the vehicle 100 based on the traffic jam information and the position coordinates PC acquired via the communication device 93. An example of the specified area is an area of about several kilometers from the vehicle 100 and is a circular area centered on the vehicle 100. Subsequently, when no traffic jam has occurred within the specified area, that is, when no traffic jam has occurred on the road where the vehicle 100 is located, the execution device 91 specifies a smaller correction coefficient K than when a traffic jam has occurred on the road. Then, the execution device 91 sets, as the permitted vehicle speed Z, a value obtained by multiplying the predetermined first reference vehicle speed A by the correction coefficient K. Here, an example of the first reference vehicle speed A is about ten to several tens of kilometers per hour. Also, the correction coefficient K is a positive value. After step S21, the execution device 91 ends the current setting control.

[0042] On the other hand, if the execution device 91 determines in step S11 that the autonomous driving mode has been selected as the driving mode of the vehicle 100 (S11: NO), the execution device 91 proceeds to step S22.

[0043] In step S22, the execution device 91 sets the permissible vehicle speed Z based on a predetermined second reference vehicle speed B. Specifically, first, the execution device 91 specifies a correction coefficient K when setting the permissible vehicle speed Z. Here, the process of specifying the correction coefficient K in step S22 is the same as the process of specifying the correction coefficient K in step S21. Then, the execution device 91 sets the permissible vehicle speed Z to a value obtained by multiplying the predetermined second reference vehicle speed B by the correction coefficient K. Here, an example of the second reference vehicle speed B is approximately 10 kilometers per hour to several tens of kilometers per hour. The second reference vehicle speed B is lower than the first reference vehicle speed A. Therefore, when the autonomous driving mode is selected, the execution device 91 sets a lower permissible vehicle speed Z than when the manual driving mode is selected. In other words, if all conditions other than the driving mode of the vehicle 100 are the same, the permissible vehicle speed Z when the autonomous driving mode is selected is lower than the permissible vehicle speed Z when the manual driving mode is selected.

[0044] In this embodiment, the processes of steps S21 and S22 are an example of a setting process. Furthermore, in the processes of steps S21 and S22, the execution device 91 specifies the correction coefficient K as described above, thereby realizing the following process. That is, in the setting process, the execution device 91 sets a lower permissible vehicle speed Z when the oil temperature TA is high compared to when the oil temperature TA is low. Furthermore, in the setting process, when a preceding vehicle is not traveling in a specific area that is predetermined as an area from the vehicle 100 up to a certain distance ahead of the vehicle 100, the execution device 91 sets a lower permissible vehicle speed Z compared to when a preceding vehicle is traveling in the specific area. Furthermore, in the setting process, when there is no traffic congestion on the road on which the vehicle 100 is located, the execution device 91 sets a lower permissible vehicle speed Z compared to when there is traffic congestion on the road. After step S22, the execution device 91 ends the current setting control.

[0045] <Fuel cut control> Next, the fuel cut control executed by the control device 90 will be described with reference to Fig. 4. This fuel cut control is a control for regenerating the filter 29. In this embodiment, the execution device 91 of the control device 90 starts the fuel cut control at each predetermined control cycle.

[0046] As shown in Fig. 4, when fuel cut control is started, the executing unit 91 of the control device 90 executes the processing of step S61. In step S61, the executing unit 91 determines whether or not regeneration of the filter 29 is necessary. For example, if the PM accumulation amount PS is equal to or greater than a predetermined specified value, the executing unit 91 determines that regeneration of the filter 29 is necessary. On the other hand, if the PM accumulation amount PS is less than the predetermined specified value, the executing unit 91 determines that regeneration of the filter 29 is not necessary. In step S61, if the executing unit 91 determines that regeneration of the filter 29 is necessary (S61: YES), the executing unit 91 proceeds to step S62.

[0047] In step S62, the execution device 91 determines whether or not a predetermined execution condition is satisfied. The execution device 91 determines that the execution condition is satisfied when, for example, the following conditions (1) and (2) are both satisfied:

[0048] Condition (1): Vehicle speed SP is equal to or greater than permitted vehicle speed Z. Condition (2): The vehicle's required driving force is equal to or less than a predetermined reference value. Here, the reference value is a threshold value for determining whether the vehicle required driving force is relatively small. Therefore, an example of a situation in which the execution condition is satisfied is a situation in which the vehicle 100 is traveling downhill at a certain vehicle speed SP or higher. If the execution device 91 determines in step S62 that the execution condition is satisfied (S62: YES), the execution device 91 proceeds to step S63.

[0049] In step S63, the execution unit 91 starts a fuel cut process to regenerate the filter 29 by engaging the lockup clutch 45C and stopping the supply of fuel from the port injection valves 26 and the direct injection valves 27 to the cylinders 11. Specifically, the execution unit 91 outputs a control signal to the hydraulic device 55 to engage the lockup clutch 45C of the torque converter 45 via the hydraulic device 55. The execution unit 91 also outputs a control signal to the internal combustion engine 10 to stop the supply of fuel from the port injection valves 26 and the direct injection valves 27 to the cylinders 11. This fuel cut process supplies air containing oxygen from the cylinders 11 to the filter 29. As a result, particulate matter deposited on the filter 29 is burned, thereby regenerating the filter 29. Note that, if the execution unit 91 is executing the fuel cut process at the start of step S63, it continues to execute the fuel cut process. After step S63, the execution unit 91 ends the current fuel cut control.

[0050] On the other hand, if the executing device 91 determines in the above-mentioned step S61 that regeneration of the filter 29 is not necessary (S61: NO), the executing device 91 ends the current fuel cut control. Also, if the executing device 91 determines in the above-mentioned step S62 that the execution condition is not satisfied (S62: NO), the executing device 91 ends the current fuel cut control. Note that if the executing device 91 is executing the fuel cut process when a negative determination is made in either step S61 or step S62, the executing device 91 ends the fuel cut process.

[0051] <Operation of this embodiment> When the manual driving mode is selected in the vehicle 100, for example, the deceleration of the vehicle 100 may increase due to the driver of the vehicle 100 being distracted while driving. Therefore, generally, when the automatic driving mode is selected in the vehicle 100, the deceleration of the vehicle 100 tends to be less likely to increase compared to when the manual driving mode is selected. As a result, when the automatic driving mode is selected, the period from when the vehicle 100 starts to stop until it stops is likely to be longer compared to when the manual driving mode is selected. In other words, when the automatic driving mode is selected, the period from when the lock-up clutch 45C starts to operate until the vehicle stops is likely to be longer.

[0052] <Advantages of the present embodiment> (1) In the setting control, when the automatic driving mode is selected, the execution device 91 sets a lower permitted vehicle speed Z compared to when the manual driving mode is selected. As described above, when the automatic driving mode is selected, the period from when the lock-up clutch 45C starts to operate until the vehicle stops is likely to be longer. Therefore, even if the permitted vehicle speed Z is low, it is possible to release the lock-up clutch 45C before the vehicle stops. And when the automatic driving mode is selected, by lowering the permitted vehicle speed Z, it is likely to be determined that the execution conditions are satisfied in step S62 of the fuel cut control. That is, when the automatic driving mode is selected, the frequency of executing the fuel cut process in step S63 of the fuel cut control becomes higher. As a result, the regeneration frequency of the filter 29 can be improved.

[0053] (2) In the vehicle 100, the higher the oil temperature TA, the shorter the period from when the lock-up clutch 45C starts to operate until it completes the operation. In this regard, in the setting control, when the oil temperature TA is high, the execution device 91 sets a lower permitted vehicle speed Z compared to when the oil temperature TA is low. Thereby, the permitted vehicle speed Z can be lowered in a situation where it is easy to complete the release of the lock-up clutch 45C before the vehicle stops.

[0054] (3) Generally, when there is no preceding vehicle traveling in a specific area predefined as an area from the vehicle 100 to a certain distance ahead of the vehicle 100, the possibility of the vehicle 100 decelerating rapidly is lower than when there is a preceding vehicle traveling in the specific area. In this regard, in the setting control, when there is no preceding vehicle traveling in the specific area predefined as an area from the vehicle 100 to a certain distance ahead of the vehicle 100, the execution device 91 sets a lower permitted vehicle speed Z compared to the case where there is a preceding vehicle traveling in the specific area. Thereby, in a situation where the possibility of the vehicle 100 decelerating rapidly is low, that is, in a situation where the period from when the lock-up clutch 45C starts operating until the vehicle stops tends to be long, the permitted vehicle speed Z can be lowered.

[0055] (4) Generally, when there is no traffic jam on the road where the vehicle 100 is located, the possibility of the vehicle 100 decelerating rapidly is lower than when there is a traffic jam on the road. In this regard, in the setting control, when there is no traffic jam on the road where the vehicle 100 is located, the execution device 91 sets a lower permitted vehicle speed Z compared to the case where there is a traffic jam on the road. Thereby, in a situation where the possibility of the vehicle 100 decelerating rapidly is low, that is, in a situation where the period from when the lock-up clutch 45C starts operating until the vehicle stops tends to be long, the permitted vehicle speed Z can be lowered.

[0056] (5) When the automatic driving mode is selected, the execution device 91 executes a release process for releasing the lock-up clutch 45C when the vehicle speed SP is less than a predetermined permitted vehicle speed Z. On the other hand, when the manual driving mode is selected, the execution device 91 executes a release process for releasing the lock-up clutch 45C when the vehicle speed SP is less than the predetermined permitted vehicle speed Z and the brake device 61 is operating. According to this vehicle 100, when the automatic driving mode is selected, the timing at which the release process is executed tends to be earlier than when the manual driving mode is selected. Therefore, when the automatic driving mode is selected, the period from when the lock-up clutch 45C starts to operate until the vehicle stops tends to be longer. Therefore, in the above vehicle 100, it is particularly preferable to apply a technique of lowering the permitted vehicle speed Z when the automatic driving mode is selected.

[0057] <Modified Example> This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically non - conflicting range.

[0058] · In the above embodiment, the setting control may be changed. For example, the method of setting the permitted vehicle speed Z in steps S21 and S22 may be changed. As a specific example, the execution device 91 may set a constant permitted vehicle speed Z regardless of whether traffic congestion has occurred on the road where the vehicle 100 is located. Also, as a specific example, the execution device 91 may set a constant permitted vehicle speed Z regardless of whether a preceding vehicle is traveling in a specific area predetermined as an area from the vehicle 100 to a certain distance ahead of the vehicle 100. As a specific example, the execution device 91 may set a constant permitted vehicle speed Z regardless of the oil temperature TA.

[0059] · In the above embodiment, the fuel cut control may be changed. For example, the execution conditions in step S62 may be changed. As a specific example, even if the condition (2) is not met, when the condition (1) is satisfied, the execution device 91 may determine that the execution conditions are satisfied. That is, the necessary condition for executing the fuel cut process may be only the requirement that the vehicle speed SP is equal to or higher than the permitted vehicle speed Z.

[0060] · In the above embodiment, the conditions for executing the release process may be changed. For example, the conditions for executing the release process may be the same whether the automatic driving mode is selected or the manual driving mode is selected. As a specific example, when the automatic driving mode is selected, if the vehicle speed SP is less than the predetermined permitted vehicle speed Z and the brake device 61 is operating, the execution device 91 may execute the release process for releasing the lock-up clutch 45C.

Explanation of Signs

[0061] 10…Internal combustion engine 11…Cylinder 12…Intake passage 13…Exhaust passage 16…Piston 17…Connecting rod 18…Crankshaft 23…Throttle valve 24…Ignition device 26…Port injection valve 27…In-cylinder injection valve 28…Three-way catalyst 29…Filter 30…Motor generator 40…Power transmission device 41…Case 42…Damper 43…Connecting shaft 44…Clutch 45…Torque converter 45A…Input shaft 45B…Output shaft 45C…Lock-up clutch 45D…Pump impeller 45E…Turbine impeller 46…Automatic transmission 51…Differential 52…Drive wheel 55…Hydraulic device 61…Brake device 81…Accelerator operation amount sensor 82…Vehicle speed sensor 83…Crank angle sensor 84…Airflow meter 85…Oil temperature sensor 86…Inter-vehicle distance sensor 87…Brake operation amount sensor 88…GNSS receiver 89…Changeover switch 90…Control device 91…Execution device 92…Storage device 92A…Control program 93…Communication device 100…Vehicle

Claims

1. An internal combustion engine having a cylinder which is a space for burning fuel, a fuel injection valve for supplying fuel into the cylinder, an exhaust passage connected to the cylinder, a three-way catalyst located in the exhaust passage for purifying exhaust gas, a filter located downstream of the three-way catalyst in the exhaust passage for collecting particulate matter contained in the exhaust gas, and a crankshaft that rotates based on the combustion of fuel in the cylinder, a fluid coupling having a lock-up clutch and transmitting power from the crankshaft to drive wheels via the lock-up clutch, which is applied to a vehicle equipped with, a fuel cut process for regenerating the filter by stopping the supply of fuel from the fuel injection valve to the cylinder while engaging the lock-up clutch, with the requirement that the vehicle speed, which is the speed of the vehicle, is equal to or higher than a predetermined permitted vehicle speed, a release process for releasing the lock-up clutch with the requirement that the vehicle speed is lower than the permitted vehicle speed, a selection process for selecting one of a manual driving mode in which the vehicle is driven according to an operation of a driver of the vehicle and an automatic driving mode in which the vehicle is driven instead of the driver's operation, a setting process for setting a lower permitted vehicle speed when the automatic driving mode is selected than when the manual driving mode is selected, and is capable of executing a control device for a vehicle.

2. In the setting process, when the oil temperature, which is the temperature of the oil that operates the lock-up clutch, is high, a lower permitted vehicle speed is set than when the oil temperature is low The control device for a vehicle according to claim 1.

3. In the setting process, when there is no preceding vehicle traveling in a specific area predetermined as an area from the vehicle to a certain distance ahead of the vehicle, a lower permitted vehicle speed is set than when there is a preceding vehicle traveling in the specific area The control device for a vehicle according to claim 1 or claim 2.

4. In the setting process, when there is no traffic jam on the road where the vehicle is located, a lower permitted vehicle speed is set than when there is a traffic jam on the road The control device for a vehicle according to claim 1 or claim 2.

5. When the automatic driving mode is selected, the release process is executed when the vehicle speed is lower than the permitted vehicle speed, When the manual driving mode is selected, execute the release process when the vehicle speed is less than the permitted vehicle speed and the braking device of the vehicle is operating. The vehicle control device according to claim 1 or claim 2.

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