Vehicle control device

Abstract

To prevent an excessive regenerative power generation from being performed by operation of deceleration support control.SOLUTION: An electronic control unit 100 prohibits increase in braking torque if fuel cut of an engine 10 is prohibited at deceleration support control which increases braking torque from which a power unit generates at deceleration of the vehicle in comparison with when same prediction is not performed if it is predicted that the vehicle decelerates.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] A vehicle control device described in Patent Document 1 is known as a device for controlling a vehicle having a regenerative braking device that generates electricity using power transmitted from the wheels. The engine of the vehicle controlled by the vehicle control device is equipped with a filter device that collects PM (Particulate Matter) in the exhaust. In such an engine, if a fuel cut is performed while a large amount of PM is collected in the filter device, the temperature of the filter may excessively rise due to heat generated by the combustion of the PM. Therefore, the vehicle control device of the above-mentioned Document 1 prohibits the engine fuel cut when the amount of PM collected in the filter device exceeds a certain value. If the fuel cut is prohibited during deceleration of the vehicle, the engine brake becomes less effective, and the deceleration of the vehicle decreases. Therefore, when the fuel cut is prohibited, the vehicle control device of the above-mentioned Document 1 suppresses the decrease in the deceleration of the vehicle by increasing the regeneration amount of the regenerative braking device during deceleration of the vehicle.

[0003] On the other hand, Patent Document 2 describes a vehicle control device that performs predictive deceleration support control. When performing predictive deceleration support control, the vehicle control device predicts whether the vehicle will decelerate from vehicle position information. When vehicle deceleration is predicted, the vehicle control device increases the amount of regeneration of the regenerative braking device during vehicle deceleration compared to when deceleration is not predicted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-105184 A [Patent Document 2] JP 2017-028749 A Summary of the Invention [Problem to be solved by the invention]

[0005] Consider implementing the predictive deceleration support control described in the above-mentioned document 2 in the vehicle control device of the above-mentioned document 1. In such a case, there is a possibility that an increase in the regeneration amount due to the predictive deceleration support control and an increase in the regeneration amount due to the prohibition of fuel cut are implemented simultaneously. As a result, there is a risk that the regenerative braking device will be required to generate an excessive regenerative braking force that exceeds the allowable upper limit. [Means for solving the problem]

[0006] The vehicle control device that solves the above problem is a device that controls a vehicle that is provided with an engine that generates power by burning fuel in a power unit connected to wheels, and a regenerative braking device that generates electricity using the power transmitted from the wheels. When it is predicted that the vehicle will decelerate, the vehicle control device controls the vehicle to generate electricity more quickly during deceleration than when the prediction is not made. By increasing the amount of regenerative power generated by the regenerative braking device, The deceleration support control is executed to increase the braking torque generated by the power unit, and when fuel cut of the engine is prohibited, braking increase prohibition processing is executed to prohibit an increase in the braking torque in the deceleration support control.

[0007] When fuel cut is prohibited, the maximum braking torque that the engine can generate is smaller than when fuel cut is not prohibited. Therefore, when fuel cut is prohibited and braking torque is increased by deceleration support control, the amount of regenerative power generation by the regenerative braking device required to ensure the increased braking torque increases, which may result in overcharging. In this regard, the above-mentioned vehicle control device prohibits an increase in braking torque by deceleration support control when engine fuel cut is prohibited. Therefore, excessive regenerative power generation by deceleration support control is less likely to occur.

[0008] Some engines are equipped with a filter device that collects particulate matter in the exhaust gas. When the vehicle control device is applied to a vehicle equipped with such an engine, the vehicle control device may be configured to prohibit the engine from cutting fuel if the amount of particulate matter collected by the filter device exceeds a predetermined threshold. In this case, overheating of the filter device due to the combustion of particulate matter caused by the fuel cut can be prevented.

[0009] The vehicle control device may be configured to perform a gradual change process to gradually bring the increase in braking torque closer to "0" when fuel cut is prohibited during an increase in braking torque due to deceleration support control. If the increase in braking torque due to deceleration support control is immediately reduced to "0" together with the prohibition of fuel cut, the braking torque may suddenly decrease, causing a deterioration in drivability. By performing the gradual change process, the change in braking torque after the prohibition of fuel cut is gradual, thereby suppressing a deterioration in drivability. The gradual change process may be terminated when the increase in braking torque due to deceleration support control is reduced to "0" or when the driver operates the shift lever. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a schematic configuration of a drive system of a vehicle that is to be controlled by an embodiment of a vehicle control device. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of the vehicle control device. [Diagram 3] 4 is a flowchart of a deceleration assistance control routine executed by the vehicle control device. [Figure 4] 3 is a flowchart of a drive torque control routine executed by the vehicle control device. [Diagram 5] 4 is a graph showing the relationship between the driver requested torque set by the vehicle control device and the vehicle speed and the accelerator pedal depression degree. [Figure 6] 4 is a flowchart of a gradual change processing routine executed by the vehicle control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of a vehicle control device will be described in detail with reference to FIGS. <Vehicle drive system configuration> First, the configuration of a drive system of a vehicle controlled by the vehicle control device of this embodiment will be described with reference to Fig. 1. The vehicle controlled by the vehicle control device of this embodiment is configured as a hybrid vehicle in which an engine 10, a first motor generator 71, and a second motor generator 72 are provided in a power unit. The engine 10 is an internal combustion engine that generates power by burning fuel. The first motor generator 71 and the second motor generator 72 are generator motors that combine a function as an electric motor that generates power by electric power supply and a function as a generator that receives power from an external source and generates power.

[0012] 1 is further provided with an on-board battery 77, a first inverter 75, and a second inverter 76. The on-board battery 77 stores electric power generated by the first motor generator 71 and the second motor generator 72 when they function as generators. Furthermore, the on-board battery 77 supplies the stored electric power to the first motor generator 71 and the second motor generator 72 when they function as motors. The first inverter 75 adjusts the amount of electric power exchanged between the first motor generator 71 and the on-board battery 77, and the second inverter 76 adjusts the amount of electric power exchanged between the second motor generator 72 and the on-board battery 77.

[0013] The engine 10 has a plurality of cylinders 11 that combust an air-fuel mixture. The engine 10 is also provided with an intake passage 15 that serves as an introduction path for air to each cylinder 11. The intake passage 15 is provided with a throttle valve 16 that is a valve for adjusting the flow rate of intake air. A portion of the intake passage 15 downstream of the throttle valve 16 is branched for each cylinder. A fuel injection valve 17 is provided in each of the branched portions of the intake passage 15 for each cylinder. Meanwhile, each cylinder 11 is provided with an ignition device 18 that ignites the air-fuel mixture introduced into the cylinder 11 by spark discharge. The engine 10 is also provided with an exhaust passage 21 that serves as an exhaust path for exhaust gas generated by the combustion of the air-fuel mixture in each cylinder 11. A three-way catalytic device 22 that purifies the exhaust gas is provided in the exhaust passage 21. Furthermore, a filter device 23 that collects particulate matter (PM) in the exhaust gas is provided downstream of the three-way catalytic device 22 in the exhaust passage 21.

[0014] An air-fuel mixture containing fuel injected by a fuel injection valve 17 is introduced into each cylinder 11 of the engine 10 through an intake passage 15. When an ignition device 18 ignites the air-fuel mixture, combustion takes place in the cylinder 11. Exhaust gas generated by this combustion is discharged from inside the cylinder 11 into an exhaust passage 21. In this engine 10, a three-way catalytic device 22 oxidizes HC and CO in the exhaust gas and reduces NOx, and a filter device 23 collects PM in the exhaust gas, thereby purifying the exhaust gas.

[0015] On the other hand, the hybrid vehicle is provided with a first planetary gear mechanism 40. The first planetary gear mechanism 40 has a sun gear 41 which is an external gear, and a ring gear 42 which is an internal gear and is arranged coaxially with the sun gear 41. Between the sun gear 41 and the ring gear 42, a plurality of pinion gears 43 which mesh with both the sun gear 41 and the ring gear 42 are arranged. Each pinion gear 43 is supported by a carrier 44 in a state in which it can freely rotate and revolve. The sun gear 41, the ring gear 42, and the carrier 44 are three rotating elements of the first planetary gear mechanism 40. The crankshaft 14 which is the output shaft of the engine 10 is connected to the carrier 44 of the first planetary gear mechanism 40, and the first motor generator 71 is connected to the sun gear 41. In addition, a drive shaft 45 is connected to the ring gear 42. The drive shaft 45 is connected to a wheel 62 via a reduction mechanism 60, a differential mechanism 61, and a wheel axle 63. That is, the drive shaft 45 serves as a shaft for extracting power to the wheels 62. The first planetary gear mechanism 40 functions as a power split mechanism that splits the power of the engine 10 between the first motor generator 71 and the drive shaft 45.

[0016] The second motor generator 72 is connected to the drive shaft 45 via the second planetary gear mechanism 50. The second planetary gear mechanism 50 has a sun gear 51, which is an external gear, and a ring gear 52, which is an internal gear, arranged coaxially with the sun gear 51. A plurality of pinion gears 53 meshing 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 freely rotatable but cannot revolve. The ring gear 52 of the second planetary gear mechanism 50 is connected to the drive shaft 45, and the second motor generator 72 is connected to the sun gear 51. The second planetary gear mechanism 50 functions as a reduction mechanism that reduces the speed of the rotation of the second motor generator 72 and transmits it to the drive shaft 45. In this embodiment, the second motor generator 72 corresponds to a regenerative braking device that generates electricity using the power transmitted from the wheels 62.

[0017] <Configuration of the vehicle control device> Next, the configuration of the vehicle control device of this embodiment will be described with reference to FIG. The hybrid vehicle is equipped with an electronic control unit 100 as a vehicle control device. The electronic control unit 100 includes an arithmetic processing device 101 that executes various processes for vehicle control, and a storage device 102 that stores programs and data for vehicle control. In reality, the electronic control unit 100 is composed of multiple control units for engine control, battery control, etc.

[0018] The hybrid vehicle is equipped with sensors such as an air flow meter 103, a crank angle sensor 104, an air-fuel ratio sensor 105, an accelerator pedal sensor 106, a shift position sensor 107, and a vehicle speed sensor 108. The air flow meter 103 is a sensor that detects the intake air amount GA of the engine 10. The crank angle sensor 104 is a sensor that detects the rotational phase of the crankshaft 14. The air-fuel ratio sensor 105 is a sensor that detects the air-fuel ratio of the mixture burned in the cylinder 11. The accelerator pedal sensor 106 is a sensor that detects the accelerator pedal operation amount ACC by the driver. The shift position sensor 107 is a sensor that detects the operation position of the shift lever by the driver. The vehicle speed sensor 108 is a sensor that detects the vehicle speed V of the hybrid vehicle.

[0019] Detection signals from these sensors are input to an electronic control unit 100. The electronic control unit 100 executes various controls for the hybrid vehicle based on the detection results of these sensors. For example, the electronic control unit 100 controls the operation of the engine 10 through control of a throttle valve 16, a fuel injection valve 17, an ignition device 18, etc. The electronic control unit 100 also controls the torque of the first motor generator 71 and the second motor generator 72 through control of a first inverter 75 and a second inverter 76.

[0020] Meanwhile, the electronic control unit 100 is also connected to a navigation device 110. The navigation device 110 includes a GPS sensor that detects the current position of the vehicle based on radio waves from a GPS (Global Positioning System) satellite. The navigation device 110 also includes an acceleration sensor that detects the driving direction of the vehicle, a memory unit that stores road information, a wireless communication device that receives road information from the outside, and a display device that provides various information to the driver. The navigation device 110 also includes a main control unit that calculates the driving route of the vehicle to the destination set by the driver and the arrival time to perform route guidance. The road information stored in the memory unit of the navigation device 110 includes road map information, road type information, road shape information, legal speed information, intersection position information, and stop line position information. The navigation device 110 is also configured to acquire traffic light information and congestion information from an external communication device installed on the road. The navigation device 110 also has a function of recording driving history information such as the driving route and driving speed of the vehicle in its own memory unit.

[0021] Furthermore, the electronic control unit 100 is also connected to a display unit 111 installed in front of the driver's seat. The electronic control unit 100 causes the display unit 111 to display various information related to the driving status of the hybrid vehicle.

[0022] <Driving control of hybrid vehicles> The electronic control unit 100 configured as above performs driving control of the hybrid vehicle based on the input detection signals and information. During driving control, the electronic control unit 100 sets the value of the target driving torque T* based on the accelerator pedal operation amount ACC, the vehicle speed V, etc. The target driving torque T* represents a target value of the torque of the drive shaft 45 generated by the power unit. The electronic control unit 100 sets the value of the target driving torque T* in a target driving torque setting routine (FIG. 4) described later.

[0023] Then, the electronic control unit 100 controls the torque of the engine 10, the first motor generator 71, and the second motor generator 72 so that the torque of the drive shaft 45 generated by the power unit becomes equal to the target drive torque T*. At this time, the electronic control unit 100 determines the distribution of the torque generated by the engine 10, the first motor generator 71, and the second motor generator 72 based on the efficiency of the engine 10 and the charging state of the on-board battery 77.

[0024] Note that the electronic control unit 100 may set a negative value as the value of the target drive torque T* when the hybrid vehicle is decelerating, etc. In this case, the electronic control unit 100 executes torque control of the engine 10, the first motor generator 71, and the second motor generator 72 so that the power unit generates a braking torque on the drive shaft 45. Furthermore, the electronic control unit 100 may execute a fuel cut of the engine 10 to generate engine brake depending on the situation.

[0025] <Fuel cut prohibition processing> As described above, the engine 10 is provided with the filter device 23 that collects PM in the exhaust gas. When a fuel cut is performed, the gas in the exhaust passage 21 is replaced with fresh air, causing a large amount of oxygen to flow into the filter device 23. The oxygen then burns the PM collected in the filter device 23. Therefore, when a fuel cut is performed in a state where a large amount of PM is collected, there is a risk that the temperature of the filter device 23 will rise above the allowable upper limit due to heat generated by the combustion of the PM.

[0026] On the other hand, the electronic control unit 100 estimates the amount of PM trapped in the filter device 23 based on the operating conditions of the engine 10. When the amount of PM trapped exceeds a predetermined threshold, the electronic control unit 100 prohibits the execution of fuel cut. The electronic control unit 100 indicates that fuel cut is prohibited by setting an FC prohibition flag.

[0027] <Deceleration support control> Next, the deceleration support control executed by the electronic control unit 100 will be described with reference to Fig. 3. In the hybrid vehicle described above, the second motor generator 72 performs regenerative power generation during deceleration, thereby converting the braking energy of the vehicle into electric power and recovering it. Meanwhile, the electronic control unit 100 predicts whether deceleration will occur while the hybrid vehicle is traveling. Then, based on the result of the deceleration prediction, the electronic control unit 100 executes deceleration support control to increase the efficiency of recovering electric power during deceleration.

[0028] The deceleration prediction is performed, for example, as follows. When the driver releases the brake pedal, i.e., when the driver releases the brake pedal, the electronic control unit 100 records the position of the vehicle at that time as the deceleration end position. The electronic control unit 100 also records the vehicle speed V when the deceleration end position is reached as the deceleration end vehicle speed. The electronic control unit 100 further stores the deceleration end position at which the brake pedal is released with a frequency equal to or greater than a certain frequency as the target deceleration end position. The electronic control unit 100 also stores the average value of the deceleration end vehicle speeds at the positions stored as the target deceleration end positions as the target deceleration end vehicle speed.

[0029] Fig. 3 shows a flow of processing of the electronic control unit 100 for deceleration support control. In step S100 in Fig. 3, the electronic control unit 100 waits until it is predicted that deceleration will occur. Then, when it is predicted that deceleration will occur (S100: YES), the electronic control unit 100 advances the processing to step S110.

[0030] In step S110, the electronic control unit 100 reads the stored target deceleration end position and target deceleration end vehicle speed. Then, in step S120, the electronic control unit 100 calculates the accelerator off induction timing, which is the time to guide the driver to release the accelerator pedal. The electronic control unit 100 guides the driver to release the accelerator pedal by displaying a guidance message on the display unit 111 to encourage the driver to release the accelerator pedal. Alternatively, the accelerator off induction may be performed by voice guidance or the like.

[0031] The electronic control unit 100 calculates the accelerator-off induction timing as follows. The electronic control unit 100 calculates the deceleration start position where the efficiency of power recovery during deceleration becomes high and the vehicle speed V at the time of reaching the target deceleration end position becomes the target deceleration end vehicle speed. The electronic control unit 100 then calculates the time when the deceleration start position is predicted to be reached after a predetermined time TS as the accelerator-off induction timing. Note that the predetermined time TS is set to the time required for the driver to release the accelerator pedal in response to the accelerator-off induction.

[0032] When the calculated accelerator-off induction timing is reached (S130: YES), the electronic control unit 100 starts the accelerator-off induction in step S140. After that, when a predetermined time TS has elapsed from the start of the induction (S150: YES) and the accelerator pedal is released (S160: YES), the electronic control unit 100 sets a braking increase flag in step S170. Then, when the hybrid vehicle reaches a target deceleration end position (S180: YES), the electronic control unit 100 clears the braking increase flag in step S190 and returns the process to step S100. Note that, in the drive torque control described below, the electronic control unit 100 increases the braking torque of the hybrid vehicle during the period when the braking increase flag is set.

[0033] <Setting the target driving torque> Next, the processing of the electronic control unit 100 related to setting the target drive torque T* will be described with reference to Fig. 4. While the hybrid vehicle is running, the electronic control unit 100 repeatedly executes the processing of the target drive torque setting routine shown in Fig. 4 at every predetermined control period.

[0034] When the target driving torque control routine is started, first in step S200, the electronic control unit 100 calculates the driver required torque TD based on the accelerator pedal operation amount ACC and the vehicle speed V. The driver required torque TD represents the driving torque of the hybrid vehicle required to realize the driving requested by the driver through the operation of the accelerator pedal.

[0035] 5, the relationship between vehicle speed V and driver required torque TD when accelerator pedal operation amount ACC is 0%, 25%, 50%, 75%, and 100% is shown by a solid line. As shown in the figure, when accelerator pedal operation amount ACC is 0%, the value of driver required torque TD is set to a negative value when vehicle speed V is in a range above a certain value.

[0036] Next, in step S210, the electronic control unit 100 determines whether or not the gradual change flag is set. If the gradual change flag is set (YES), the electronic control unit 100 proceeds to step S290, and if the gradual change flag is not set (NO), the electronic control unit 100 proceeds to step S220. If the electronic control unit 100 proceeds to step S290, the electronic control unit 100 performs the gradual change process described below in step S290.

[0037] When the process proceeds to step S220, the electronic control unit 100 determines whether or not the braking increase flag is set in the deceleration support control described above in step S220. If the braking increase flag is not set (NO), the electronic control unit 100 sets the driver request torque TD as the value of the target driving torque T* in step S230, and ends the process of this routine.

[0038] On the other hand, if the braking increase flag is not set (S220: NO), the electronic control unit 100 determines in step S240 whether the FC prohibition flag is set, i.e., whether fuel cut of the engine 10 is prohibited. If the FC prohibition flag is not set (NO), the electronic control unit 100 calculates the braking increase required torque TBG in step S250. Then, in step S260, the electronic control unit 100 sets the braking increase required torque TBG as the value of the target drive torque T*, and ends the processing of this routine.

[0039] In Fig. 5, the relationship between the braking increased torque required TBG and the vehicle speed V is shown by a dotted line. As shown in the figure, the value of the braking increased torque required TBG is calculated to be a value smaller than the driver required torque TD when the accelerator pedal operation amount ACC is 0%.

[0040] 4, if the electronic control unit 100 determines that the FC prohibition flag is set (YES), the electronic control unit 100 clears the braking increase flag in step S270. Next, the electronic control unit 100 sets the gradual change flag in step S280. Then, the electronic control unit 100 advances the process to step S290 and performs the gradual change process.

[0041] As described above, in the deceleration support control, when it is predicted that the hybrid vehicle will decelerate, the accelerator release guidance is performed. In the deceleration support control, the braking increase flag is set when the vehicle decelerates in response to the accelerator release guidance.

[0042] On the other hand, in the target drive torque setting routine, basically, when the braking increase flag is cleared, the driver required torque TD is set as the value of the target drive torque T*, and when the braking increase flag is set, the braking increase required torque TBG is set as the value of the target drive torque T*. As described above, the braking increase required torque TBG is set to a value smaller than the driver required torque TD when the accelerator pedal operation amount ACC is 0%, that is, a value that increases the braking torque. Therefore, in the deceleration support control, when it is predicted that the vehicle will decelerate, the braking torque generated by the power unit during vehicle deceleration is increased compared to when the prediction is not made.

[0043] In this embodiment, even if the braking increase flag is set, if the FC prohibition flag is set, i.e., if fuel cut of the engine 10 is prohibited, the braking increase flag is cleared. That is, in this embodiment, if fuel cut of the engine 10 is prohibited, an increase in the braking torque in the deceleration support control is prohibited. In this embodiment, the processes of steps S240 and S270 in FIG. 4 correspond to the braking increase prohibition process.

[0044] In addition, in the target drive torque setting routine, if the braking increase flag is set and the FC prohibition flag is set, the gradual change flag is set. If the gradual change flag is set, the gradual change process is carried out.

[0045] <Gradual change processing> Next, the gradual change processing performed by the electronic control unit 100 when the processing proceeds to step S290 in Fig. 4 will be described with reference to Fig. 6. Fig. 6 shows a flowchart of a gradual change processing routine executed by the electronic control unit 100 during the gradual change processing.

[0046] When the electronic control unit 100 starts the gradual change processing routine, first in step S300, the sum of the previous value of the target drive torque T* and a predetermined gradual change constant ΔT is calculated as the value of the gradual change target torque TSM. The previous value represents the calculated value of the target drive torque T* in the previous control cycle.

[0047] Then, if neither of the following conditions (A) and (B) is satisfied (S310: NO and S320: NO), the electronic control unit 100 advances the process to step S330. When the process advances to step S330, the electronic control unit 100 sets the value of the gradual-change target torque TSM as the value of the target driving torque T* in step S330, and then ends the process of this routine in the current control cycle. The condition (A) is that the gradual-change target torque TSM is equal to or greater than the driver required torque TD (S310: YES). The satisfaction of the condition (A) indicates that the increase in the braking torque due to the deceleration support control has decreased to "0" through the gradual-change process. The condition (B) is that the driver has operated the shift lever.

[0048] On the other hand, if at least one of the above conditions (A) and (B) is satisfied, the electronic control unit 100 advances the process to step S340. Then, the electronic control unit 100 clears the gradual change flag in step S340, and then sets the driver request torque TD as the value of the target driving torque T* in step S350, and then ends the process of this routine. Note that, since the gradual change flag is cleared at this time, the gradual change process will not be performed in the next control cycle. In other words, the gradual change process is ended.

[0049] <Effects of the embodiment> Next, the operation of the vehicle control device of this embodiment will be described. When the driver applies sudden braking just before the deceleration end position to decelerate, the amount of electric power that can be recovered by regenerative braking is less than when the vehicle is decelerated by regenerative braking sufficiently before the deceleration end position. In response to this, the electronic control unit 100 executes the following deceleration support control. That is, in the deceleration support control, the electronic control unit 100 induces the driver to release the accelerator pedal when it predicts that the vehicle will decelerate. Then, when the driver releases the accelerator pedal in response to the induction and the vehicle starts to decelerate, the electronic control unit 100 increases the braking torque generated by the power unit compared to normal deceleration. The above-mentioned induction makes it easier for the vehicle to be decelerated by regenerative braking rather than sudden braking. In addition, the increase in braking torque increases the amount of regenerative power generated during the vehicle deceleration. Therefore, the amount of electric power that can be recovered during the vehicle deceleration increases.

[0050] In addition, when the amount of PM trapped in the filter device 23 exceeds a certain amount, the electronic control unit 100 prohibits the fuel cut of the engine 10 in order to prevent the filter device 23 from overheating. When the fuel cut is prohibited, the braking torque that the engine 10 can generate, that is, the braking torque by the engine brake, becomes smaller. Therefore, when the fuel cut is prohibited, the regenerative torque of the first motor generator 71 and the second motor generator 72 required to ensure the braking torque increased by the deceleration support control becomes larger than when the fuel cut is not prohibited. On the other hand, there is an upper limit to the charge amount per hour of the vehicle-mounted battery 77. Therefore, if the braking torque is increased by the deceleration support control in a state in which the fuel cut is prohibited, excessive regeneration is performed, which may cause the vehicle-mounted battery 77 to be overcharged.

[0051] In the hybrid vehicle, the engine 10, the first motor generator 71, and the drive shaft 45 are connected via the first planetary gear mechanism 40. In such a hybrid vehicle, when the rotation speed of the drive shaft 45 decreases while the rotation speed of the engine 10 is maintained, the rotation speed of the first motor generator 71 increases. On the other hand, when the braking torque is increased by the deceleration assist control, the rotation speed of the drive shaft 45 decreases faster during vehicle deceleration than usual. At this time, if a fuel cut is performed, the rotation speed of the engine 10 decreases quickly, so that the increase in the rotation speed of the first motor generator 71 is suppressed to an allowable range. However, if the fuel cut is prohibited, the decrease in the rotation speed of the engine 10 becomes slow, so that there is a risk that the rotation speed of the first motor generator 71 increases beyond an allowable limit.

[0052] On the other hand, when fuel cut is prohibited, the electronic control unit 100 prohibits an increase in the braking torque in the deceleration support control, which makes it difficult for the above-mentioned overcharging of the in-vehicle battery 77 and over-rotation of the first motor generator 71 to occur.

[0053] Incidentally, it is conceivable that fuel cut is prohibited during an increase in braking torque due to deceleration support control, and an increase in braking torque is prohibited. If the increase in braking torque due to deceleration support control is immediately stopped together with the prohibition of fuel cut, the braking torque may suddenly decrease, causing the occupants to feel uncomfortable. In response to this, the electronic control unit 100 performs gradual change processing when fuel cut is prohibited during an increase in braking torque due to deceleration support control. In the gradual change processing, the electronic control unit 100 increases the target drive torque T* by a predetermined gradual change constant ΔT for each control cycle. That is, in the gradual change processing, when fuel cut is prohibited during an increase in braking torque due to deceleration support control, the electronic control unit 100 gradually brings the increase amount of the braking torque closer to "0". Therefore, a sudden decrease in braking torque when fuel cut is prohibited during an increase in braking torque due to deceleration support control is suppressed.

[0054] The electronic control unit 100 ends the gradual change process when the gradual change target torque TSM reaches the driver required torque TD, that is, when the increase in the braking torque due to the speed support control becomes "0". The electronic control unit 100 also ends the gradual change process when the driver operates the shift lever during the gradual change process. The driver operates the shift lever for the purpose of changing the driving torque. Therefore, even if the braking torque changes suddenly after the shift lever is operated, the driver is unlikely to feel uncomfortable. Therefore, when the shift lever is operated, the electronic control unit 100 ends the gradual change process so that the driving requested by the driver can be quickly achieved.

[0055] According to the vehicle control device of this embodiment, the following effects can be achieved. (1) When it is predicted that the vehicle will decelerate, the vehicle control device of this embodiment performs deceleration support control to increase the braking torque generated by the power unit when the vehicle decelerates, compared to when the prediction is not made. When fuel cut of the engine 10 is prohibited, the vehicle control device performs deceleration support prohibition processing to prohibit an increase in the braking torque by the deceleration support control. Therefore, in a state in which fuel cut is prohibited, the braking torque is not increased by the deceleration support control. Therefore, overcharging of the on-board battery 77 due to excessive regenerative braking is less likely to occur.

[0056] (2) The vehicle control device of this embodiment prohibits fuel cut of the engine 10 when the amount of PM trapped in the filter device 23 installed in the engine 10 exceeds a predetermined threshold. This prevents the PM trapped in the filter device 23 from burning due to fuel cut, which would cause the filter device 23 to overheat.

[0057] (3) In a state in which the rotation speed of the engine 10 is difficult to decrease due to the prohibition of fuel cut, the braking torque is not increased by the deceleration assist control. Therefore, the first motor generator 71 is less likely to overreach.

[0058] (4) When fuel cut is prohibited during an increase in braking torque due to deceleration support control, the vehicle control device of this embodiment executes a gradual change process to gradually bring the increase in braking torque due to deceleration support control closer to 0. This makes it possible to suppress deterioration of drivability due to a sudden decrease in braking torque.

[0059] (5) During the gradual change process, the driving torque generated by the power unit does not match the driver's request. In response to this, the vehicle control device of this embodiment ends the gradual change process when the increase in braking torque due to the deceleration support control decreases to 0 or when the shift lever is operated. This prevents the driving torque generated by the power unit from deviating from the driver's request from continuing for an unnecessarily long period of time.

[0060] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0061] In the above embodiment, fuel cut of the engine 10 is prohibited when the amount of PM trapped in the filter device 23 exceeds a threshold value, but fuel cut may be prohibited under other conditions. For example, if fuel cut is performed when the deterioration of the three-way catalyst device 22 has progressed, the deterioration of the three-way catalyst device 22 may be accelerated. Therefore, fuel cut may be prohibited when the degree of deterioration of the three-way catalyst device 22 exceeds a threshold value.

[0062] The conditions for ending the gradual change processing in the above embodiment may be changed. For example, the gradual change processing may be ended when the driver depresses the accelerator pedal. Even when fuel cut is prohibited while the braking torque is increasing due to the deceleration assistance control, the driver requested torque TD may be immediately set to the target driving torque T* without performing the gradual change process.

[0063] The second motor generator 72 is configured as a generator motor that functions both as an electric motor and as a generator. Instead of the second motor generator 72, a device dedicated to regenerative power generation may be used. In other words, it is sufficient if it has the function of a regenerative braking device that generates power using the power transmitted from the wheels 62.

[0064] The vehicle control device of the above embodiment may be applied to a hybrid vehicle having a configuration different from that shown in Fig. 1. For example, the vehicle control device of the above embodiment may be applied to a hybrid vehicle having an engine, a regenerative braking device, and wheels connected in series. [Explanation of symbols]

[0065] 10…Engine 11…Cylinder 14…Crankshaft 15…Intake passage 16...Throttle valve 17...Fuel injector 18...Ignition device 21...Exhaust passage 22…Three-way catalyst device 23...Filter device 40…First planetary gear mechanism 41,51…Sun gear 42,52…Ring gear 43,53…Pinion gear 44…Career 45…Ring gear shaft 50…Second planetary gear mechanism 60…Reduction mechanism 61…Differential mechanism 62...Wheel 63...Drive wheel 71…First motor generator 72...Second motor generator (regenerative braking device) 75…First inverter 76…Second inverter 77...Car battery 100...Electronic control unit 101... Processing device 102...Storage device 103...Air flow meter 104...Crank angle sensor 105...Air-fuel ratio sensor 106...Accelerator pedal sensor 107...Shift position sensor 108...Vehicle speed sensor 110...Navigation equipment 111...Display section

Claims

1. A device for controlling a vehicle having a power unit connected to wheels, an engine that generates power by burning fuel, and a regenerative braking device that generates power using power transmitted from the wheels, When it is predicted that the vehicle will decelerate, a deceleration support control is performed to increase the amount of regenerative power generated by the regenerative braking device when the vehicle decelerates, thereby increasing the braking torque generated by the power unit, compared to when the prediction is not made. a braking increase prohibition process for prohibiting an increase in the braking torque in the deceleration assist control when a fuel cut of the engine is prohibited; A vehicle control device that executes the above.

2. the engine is provided with a filter device for trapping particulate matter in the exhaust; The vehicle control device according to claim 1 , further comprising: a control unit for controlling the vehicle to inhibit the fuel cut when an amount of the particulate matter trapped in the filter device exceeds a predetermined threshold value.

3. 2. The vehicle control device according to claim 1, wherein, when the fuel cut is prohibited while the braking torque is increasing due to the deceleration assist control, a gradual change process is executed to gradually bring an increase in the braking torque closer to "0".

4. The vehicle control device according to claim 3 , wherein the gradual change process is terminated when an increase in the braking torque due to the deceleration assist control decreases to "0".

5. 4. The vehicle control device according to claim 3, wherein the gradual change process is terminated when a driver operates a shift lever.

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