JP7397710B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device mounted on a vehicle.

Vehicles such as automobiles are equipped with a generator such as a motor generator, an alternator, or an ISG (Integrated Starter Generator). From the viewpoint of improving the energy efficiency of the vehicle, these generators are controlled to a regenerative power generation state during deceleration driving (see Patent Documents 1 to 3).

The vehicle is also equipped with an antilock braking system (ABS). This anti-lock brake system executes anti-lock control to prevent the wheels from locking by adjusting the brake fluid pressure when it is determined that the wheels tend to lock based on the wheel speed or the like.

JP2010-247782A Japanese Patent Application Publication No. 2015-146657 Japanese Patent Application Publication No. 2016-193635

By the way, in a situation where anti-lock control is executed, the generator is controlled from the regenerative power generation state to the power generation stop state from the viewpoint of preventing engine stall. However, stopping the regenerative power generation of the generator in conjunction with anti-lock control greatly reduces vehicle deceleration during anti-lock control, causing a sense of discomfort to the occupants, so it is necessary to control the generator appropriately. That is what is required.

An object of the present invention is to appropriately control a generator.

The vehicle control device of the present invention is a vehicle control device mounted on a vehicle, in which a rotational speed difference between a generator connected to a wheel via a power transmission path and the wheel exceeds a first threshold value. In this case, the vehicle includes a brake control unit that controls a brake mechanism to perform anti-lock control to suppress locking of the wheels, and a power generation control unit that controls the generator to a regenerative power generation state during deceleration traveling, The power generation control unit is configured to control the power generation torque of the power generator to a first level when the rotational speed difference exceeds a second threshold smaller than the first threshold while the power generator is controlled to a regenerative power generation state. After decreasing the speed, the generated torque of the generator is decreased toward zero at a second speed that is slower than the first speed.

According to the present invention, when the rotational speed difference between the wheels exceeds the second threshold value which is smaller than the first threshold value, the power generation torque of the generator is reduced at the first speed, and then the power generation torque of the generator is reduced to the second threshold value, which is smaller than the first threshold value. Decrease toward zero at a second speed, which is slower than the first speed. Thereby, the generator can be appropriately controlled.

1 is a schematic diagram showing a configuration example of a vehicle equipped with a vehicle control device according to an embodiment of the present invention. FIG. 2 is a circuit diagram simply showing an example of a power supply circuit. FIG. 2 is a diagram showing an example of a control system included in a vehicle control device. It is a figure which shows an example of the electric current supply situation when a starter generator is controlled to a combustion power generation state. It is a figure which shows an example of the electric current supply situation when a starter generator is controlled to a power generation stop state. It is a figure which shows an example of the current supply situation when a starter generator is controlled to a regenerative power generation state. It is a figure showing an example of the current supply situation when controlling a starter generator to a power running state. 5 is a timing chart showing an execution pattern 1 of power generation torque reduction control. 7 is a timing chart showing execution pattern 2 of power generation torque reduction control. 7 is a timing chart showing execution pattern 3 of power generation torque reduction control. 3 is a flowchart illustrating an example of an execution procedure of power generation torque reduction control.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

[Vehicle configuration]
FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle 11 equipped with a vehicle control device 10 according to an embodiment of the present invention. As shown in FIG. 1, the vehicle 11 is equipped with a power train 14 that includes an engine 12 and a transmission 13. A starter generator (power generator) 17 is connected to a crankshaft 15 of the engine 12 via a belt mechanism 16 . Further, rear wheels (wheels) 21 are connected to the transmission 13 connected to the engine 12 via a propeller shaft 18 , a rear differential mechanism 19 , and a rear wheel drive shaft 20 . (Wheel) 23 is connected. That is, the starter generator 17 and the wheels 21 and 23 are connected to each other via a power transmission path 24 that includes the transmission 13 and the like. The power transmission path 24 includes the crankshaft 15, the transmission 13, the propeller shaft 18, the rear wheel drive shaft 20, the front wheel drive shaft 22, and the like.

The starter generator 17 is a so-called ISG (Integrated Starter Generator) that functions as a generator and an electric motor. This starter generator 17 not only functions as a generator driven by the crankshaft 15 but also functions as an electric motor that drives the crankshaft 15. For example, when restarting the engine 12 in idle stop control or when assisting the engine 12 at the time of starting or accelerating, the starter generator 17 is controlled to a power running state and the starter generator 17 is driven as an electric motor. The starter generator 17 includes a stator 30 with a stator coil and a rotor 31 with a field coil. Further, the starter generator 17 is provided with an ISG controller 32 consisting of an inverter, a regulator, a microcomputer, various sensors, etc. in order to control the energization state of the stator coil and field coil. By controlling the energization state of the field coil and the stator coil by the ISG controller 32, the generated voltage, generated torque, power running torque, etc. of the starter generator 17 can be controlled.

The intake manifold 33 of the engine 12 is provided with a throttle valve 34 that adjusts the amount of intake air. Further, the engine 12 is provided with an injector 35 that injects fuel into an intake port or into a cylinder, and is provided with an ignition device 36 consisting of an igniter, a spark plug, or the like. By injecting fuel from the injector 35, the engine 12 is controlled to a fuel injection state, and by stopping fuel injection from the injector 35, the engine 12 is controlled to a fuel cut state. Further, an engine controller 37 consisting of a microcomputer or the like is connected to the throttle valve 34, injector 35, and ignition device 36.

The vehicle 11 is also provided with a brake device (brake mechanism) 40 that constitutes an antilock braking system. The brake device 40 includes a master cylinder 42 that outputs brake fluid pressure in conjunction with a brake pedal 41, and a caliper 44 that brakes the disc rotor 43 of each wheel 21, 23. Further, an actuator 45 is provided between the master cylinder 42 and the caliper 44 to control brake fluid pressure supplied to each caliper 44. This actuator 45 includes an electric pump, an accumulator, an electromagnetic valve, etc. (not shown). Further, a brake controller 46 consisting of a microcomputer or the like is connected to the actuator 45. The brake controller 46 determines the locking tendency of the wheels 21 and 23 during braking based on information from a front wheel speed sensor 93, a rear wheel speed sensor 94, etc., which will be described later. When the brake controller 46 determines that the wheels 21 and 23 have a tendency to lock, the brake controller 46 executes anti-lock control to suppress locking of the wheels 21 and 23. That is, by controlling the actuator 45 to repeatedly decrease, maintain, and increase the brake fluid pressure, the braking force of the wheels 21, 23 that tend to lock is adjusted, and the slip ratio of the wheels 21, 23 is maintained appropriately.

[Power circuit]
The power supply circuit 50 mounted on the vehicle 11 will be explained. FIG. 2 is a circuit diagram simply showing an example of the power supply circuit 50. As shown in FIG. As shown in FIG. 2, the power supply circuit 50 includes a lead battery (first power storage body) 51 electrically connected to the starter generator 17, and a lithium ion battery electrically connected to the starter generator 17 in parallel. (second power storage body) 52. Note that in order to actively discharge the lithium ion battery 52, the terminal voltage of the lithium ion battery 52 is designed to be higher than the terminal voltage of the lead battery 51. Furthermore, in order to actively charge and discharge the lithium ion battery 52, the internal resistance of the lithium ion battery 52 is designed to be smaller than the internal resistance of the lead battery 51.

A positive line 53 is connected to the positive terminal 17a of the starter generator 17, a positive line 54 is connected to the positive terminal 52a of the lithium ion battery 52, and a positive line 55 is connected to the positive terminal 51a of the lead battery 51. 56 are connected. These positive electrode lines 53, 54, 56 are connected to each other via a connection point 57. Further, a negative electrode line 58 is connected to the negative electrode terminal 17b of the starter generator 17, a negative electrode line 59 is connected to the negative electrode terminal 52b of the lithium ion battery 52, and a negative electrode line 60 is connected to the negative electrode terminal 51b of the lead battery 51. Ru. These negative electrode lines 58, 59, and 60 are connected to each other via a reference potential point 61.

As shown in FIG. 1, a positive electrode line 62 is connected to the positive electrode line 55 of the lead battery 51. Connected to this positive electrode line 62 is an electrical equipment group 64 consisting of electrical equipment 63 such as various actuators and various controllers. Further, a battery sensor 65 is provided on the negative electrode line 60 of the lead battery 51. The battery sensor 65 has a function of detecting the charging/discharging current and terminal voltage of the lead battery 51, and also has a function of detecting the state of charge (SOC) of the lead battery 51 from the charging/discharging current, etc. There is. Note that the battery sensor 65 is also connected to the positive terminal 51a of the lead battery 51 via a current supply line (not shown).

The power supply circuit 50 is provided with a first power supply system 71 consisting of a lead battery 51 and an electric device 63, and a second power supply system 72 consisting of a lithium ion battery 52 and a starter generator 17. The lead battery 51 and the lithium ion battery 52 are connected in parallel to each other via a positive electrode line 56 provided between the first power supply system 71 and the second power supply system 72. This positive electrode line 56 is provided with a power fuse 73 that is blown by excessive current, and is also provided with a first switch SW1 that is controlled to be in an on state and an off state. Further, the positive electrode line 54 of the lithium ion battery 52 is provided with a second switch SW2 that is controlled to be in an on state and an off state.

By controlling the switch SW1 to the on state, the first power supply system 71 and the second power supply system 72 can be connected to each other, while by controlling the switch SW1 to the off state, the first power supply system 71 and the second power supply system 72 can be connected to each other. The two power supply systems 72 can be separated from each other. Further, by controlling the switch SW2 to be in the on state, the starter generator 17 and the lithium ion battery 52 can be connected to each other, while by controlling the switch SW2 to be in the off state, the starter generator 17 and the lithium ion battery 52 can be connected to each other. can be separated from each other. These switches SW1 and SW2 may be switches constituted by semiconductor elements such as MOSFETs, or may be switches that mechanically open and close contacts using electromagnetic force or the like. Note that the switches SW1 and SW2 are also called relays, contactors, or the like.

As shown in FIG. 1, the power supply circuit 50 is provided with a battery module 74. This battery module 74 includes the lithium ion battery 52 and switches SW1 and SW2. Furthermore, the battery module 74 has a battery controller 75 consisting of a microcomputer, various sensors, and the like. Further, the battery module 74 is provided with a battery sensor 76 that detects the charging/discharging current, terminal voltage, temperature, etc. of the lithium ion battery 52. The battery controller 75 also has a function of calculating SOC (State of Charge), which is the state of charge of the lithium ion battery 52, based on the charging/discharging current and the like transmitted from the battery sensor 76.

[Control system]
FIG. 3 is a diagram showing an example of a control system included in the vehicle control device 10. As shown in FIGS. 1 and 3, the vehicle control device 10 includes a main controller 80 made of a microcomputer or the like. The main controller 80 is provided with an engine control section 81 that outputs a control signal to the engine controller 37 to control the engine 12, and an ISG control section that outputs a control signal to the ISG controller 32 to control the starter generator 17. (Power generation control unit) 82 is provided. The main controller 80 is also provided with a brake control section 83 that outputs a control signal to the brake controller 46 to control the brake device 40, and outputs a control signal to the battery controller 75 to control the switches SW1 and SW2. A switch control section 84 is provided. The main controller 80 and the controllers 32, 37, 46, and 75 described above are communicably connected to each other via an in-vehicle network 85 such as CAN or LIN.

Sensors connected to the main controller 80 include an accelerator pedal sensor 91 that detects the operation status of the accelerator pedal, a brake pedal sensor 92 that detects the operation status of the brake pedal 41, a front wheel speed sensor 93 that detects the rotational speed of the front wheels 23, There are a rear wheel speed sensor 94 that detects the rotational speed of the rear wheels 21, a vehicle speed sensor 95 that detects the running speed of the vehicle 11, and the like. The main controller 80 also receives the operating status of the engine 12 from the engine controller 37, receives the operating status of the starter generator 17 from the ISG controller 32, receives the operating status of the brake device 40 from the brake controller 46, and receives the operating status of the brake device 40 from the brake controller 46. The operating status of the lithium ion battery 52 and switches SW1 and SW2 is input from the controller 75.

[Starter generator power generation control]
Power generation control of the starter generator 17 will be explained. The ISG control unit 82 of the main controller 80 outputs a control signal to the ISG controller 32 to control the starter generator 17 to a power generation state. For example, when the SOC of the lithium ion battery 52 decreases, the ISG control unit 82 increases the power generation voltage of the starter generator 17 to control the combustion power generation state. Lower the voltage and control to stop power generation.

FIG. 4 is a diagram showing an example of the current supply situation when the starter generator 17 is controlled to a combustion power generation state. Note that the combustion power generation state of the starter generator 17 is a state in which the starter generator 17 generates power using engine power, that is, a state in which fuel is combusted within the engine 12 to cause the starter generator 17 to generate power. For example, when the SOC of the lithium ion battery 52 is lower than a predetermined value, the starter generator 17 is caused to generate electricity using engine power in order to charge the lithium ion battery 52. In this way, when controlling the starter generator 17 to the combustion power generation state, the generated voltage of the starter generator 17 is raised higher than the terminal voltages of the lead battery 51 and the lithium ion battery 52. As a result, as shown by the black arrow in FIG. is slowly charged.

FIG. 5 is a diagram showing an example of the current supply situation when the starter generator 17 is controlled to stop generating electricity. For example, when the SOC of the lithium ion battery 52 exceeds a predetermined value, the power generation of the starter generator 17 using engine power is stopped in order to actively discharge the lithium ion battery 52. In this way, when controlling the starter generator 17 to stop generating electricity, the generated voltage of the starter generator 17 is lowered than the terminal voltages of the lead battery 51 and the lithium ion battery 52. As a result, as shown by the black arrow in FIG. 5, current is supplied from the lithium ion battery 52 to the electrical equipment group 64, so power generation by the starter generator 17 can be stopped, reducing the engine load. I can do it. Note that the power generation voltage of the starter generator 17 in the power generation stop state may be any voltage that discharges the lithium ion battery 52. For example, the voltage generated by the starter generator 17 may be controlled to 0V, or the voltage generated by the starter generator 17 may be controlled to be higher than 0V.

As described above, the main controller 80 controls the starter generator 17 to be in the combustion power generation state or power generation stop state based on the SOC, but when the vehicle is decelerated, it is required to recover a large amount of kinetic energy to improve fuel efficiency. . Therefore, when the vehicle is decelerating, the power generation voltage of the starter generator 17 is increased, and the starter generator 17 is controlled to a regenerative power generation state. As a result, the power generated by the starter generator 17 can be increased, and kinetic energy can be actively converted into electrical energy and recovered, thereby increasing the energy efficiency of the vehicle 11 and improving fuel efficiency. can. The starter generator 17 is not only controlled to the regenerative power generation state during deceleration driving when the brake pedal 41 is depressed, but also controlled to the regenerative power generation state during deceleration driving when the accelerator pedal is released, that is, coasting. .

Here, FIG. 6 is a diagram showing an example of a current supply situation when the starter generator 17 is controlled to a regenerative power generation state. When controlling the starter generator 17 to the regenerative power generation state, the power generation voltage of the starter generator 17 is increased compared to the combustion power generation state described above. As a result, as shown by the black arrow in FIG. 6, a large current is supplied from the starter generator 17 to the lithium ion battery 52 and the lead battery 51, so the lithium ion battery 52 and the lead battery 51 rapidly It will be charged. Furthermore, since the internal resistance of the lithium ion battery 52 is smaller than the internal resistance of the lead battery 51, most of the generated current is supplied to the lithium ion battery 52.

Note that, as shown in FIGS. 4 to 6, when controlling the starter generator 17 to the combustion power generation state, regenerative power generation state, and power generation stop state, the switches SW1 and SW2 are kept in the on state. That is, in the vehicle control device 10, it is possible to control charging and discharging of the lithium ion battery 52 by simply controlling the generated voltage of the starter generator 17 without performing switching control of the switches SW1 and SW2. Thereby, not only can charging and discharging of the lithium ion battery 52 be easily controlled, but also the durability of the switches SW1 and SW2 can be improved.

[Starter generator power running control]
Power running control of the starter generator 17 will be explained. The ISG control unit 82 of the main controller 80 controls the starter generator 17 to a power running state, for example, when restarting the engine 12 in idling stop control. Here, FIG. 7 is a diagram showing an example of the current supply situation when the starter generator 17 is controlled to the power running state. As shown in FIG. 7, when controlling the starter generator 17 to the power running state when restarting the engine in the idling stop control, the switch SW1 is switched from the on state to the off state. As a result, even when a large current is supplied from the lithium ion battery 52 to the starter generator 17, it is possible to prevent an instantaneous voltage drop to the electrical equipment group 64, and the electrical equipment group 64 etc. can function normally. can be done.

In the example shown in FIG. 7, when controlling the starter generator 17 to the power running state, the switch SW1 is switched to the OFF state, but the present invention is not limited to this, and the switch SW1 may be kept in the ON state. The starter generator 17 may be controlled to be in a power running state. For example, in motor assist control that assists the engine 12 when starting or accelerating, the power consumption of the starter generator 17 is smaller than when restarting the engine as described above, so the switch SW1 is kept in the on state when the starter generator 17 is running. Ru. In this way, in the motor assist control with low power consumption, even if the switch SW1 is kept in the on state, a large current does not flow from the lead battery 51 to the starter generator 17, and the power supply voltage of the electrical equipment group 64 is stabilized. can be done.

[Generation torque reduction control]
Next, a description will be given of power generation torque reduction control that reduces the power generation torque of the starter generator 17 while antilock control is predicted during regenerative power generation. As described above, when the vehicle is decelerating when the accelerator pedal is released or when the brake pedal 41 is depressed, the starter generator 17 is controlled to the regenerative power generation state. In such a regenerative power generation state of the starter generator 17, the vehicle deceleration increases in accordance with the generated torque of the starter generator 17. Here, if the vehicle is decelerating on a slippery road surface such as a snowy road, there is a possibility that the slip ratio of the wheels 21 and 23 will increase and anti-lock control will be executed. As described above, when the anti-lock control of the brake device 40 is executed, there is a risk that the engine speed will suddenly drop due to wheel locking and an engine stall will occur, so the engine 12 is changed from the fuel cut state to the fuel injection state. The starter generator 17 is switched from the regenerative power generation state to the power generation stop state. That is, if anti-lock control is executed during regenerative power generation, the vehicle deceleration will be significantly reduced as the starter generator 17 stops generating power, which may give the occupants a sense of discomfort. Therefore, the ISG control unit 82 of the main controller 80 executes power generation torque reduction control that predicts anti-lock control and reduces the power generation torque of the starter generator 17 in advance so as not to give the occupant an excessive sense of discomfort.

(Execution pattern 1)
FIG. 8 is a timing chart showing execution pattern 1 of power generation torque reduction control. In FIG. 8 and FIGS. 9 to 10 described later, the front and rear wheel speed difference ΔN is the absolute value of the rotational speed difference obtained by subtracting the rear wheel rotational speed Nr from the front wheel rotational speed Nf, that is, the rotation between the front wheel 23 and the rear wheel 21. This is the absolute value of the speed difference. Further, the ABS flag is a flag that is set to ON when anti-lock control is executed, and the fuel cut flag is a flag that is set to ON when the engine 12 is controlled to be in a fuel cut state. Further, the power generation torque Tg is the power generation torque of the starter generator 17, and the ISG deceleration is the vehicle deceleration caused by the starter generator 17. In each of the diagrams shown in FIGS. 8 to 10, the front and rear wheel speed difference ΔN is shown below zero, the power generation side (+ side) of the power generation torque is shown below zero, and the ISG deceleration The deceleration side (+ side) of vehicle deceleration is shown below zero, and the deceleration side (+ side) of vehicle deceleration is shown below zero.

As shown at time t1a in FIG. 8, during deceleration driving, the engine 12 is controlled to be in a fuel cut state (symbol a1), and the starter generator 17 is controlled to be in a regenerative power generation state (symbol b1). At this time, the power generation torque Tg is controlled at a predetermined value T1 (symbol b1), and the ISG deceleration Dg has reached a predetermined value D1 (for example, 0.4 m/s ² ) (symbol c1). Furthermore, the front and rear wheel speed difference ΔN is approximately zero (symbol d1), and the anti-lock control is stopped (symbol e1). In the illustrated vehicle control device 10, anti-lock control is executed based on the front and rear wheel speed difference ΔN. That is, when the front and rear wheel speed difference ΔN exceeds a predetermined threshold (first threshold) N1, anti-lock control of the brake device 40 is executed.

Subsequently, as shown at time t2a, when the front wheel 23 or the rear wheel 21 starts to slip and the front and rear wheel speed difference ΔN exceeds a threshold (second threshold) N2, which is smaller than the threshold N1 (symbol d2), the main The controller 80 reduces the power generation torque Tg by a predetermined amount Xa (symbol b2), and then reduces the power generation torque Tg toward zero (symbol b3). At this time, as indicated by symbols S1 and S2, the speed at which the power generation torque Tg is reduced by a predetermined amount Xa (first speed) is set faster than the speed at which the power generation torque Tg is reduced to zero (second speed). There is. That is, when the front and rear wheel speed difference ΔN exceeds the threshold value N2 (symbol d2), the main controller 80 reduces the power generation torque of the starter generator 17 at the first speed (symbol b2), and then reduces the power generation torque of the starter generator 17. is lowered at a second speed that is slower than the first speed (symbol b3).

In this way, when the front and rear wheel speed difference ΔN exceeds the threshold value N2, the power generation torque Tg is quickly reduced by a predetermined amount Xa (symbol b2), and then the power generation torque Tg is gradually reduced toward zero. (Symbol b3). As a result, after the ISG deceleration Dg decreases by a predetermined amount Xb (for example, 0.1 m/s ² ) (code c2), the ISG deceleration Dg gradually decreases toward zero (code c3). Furthermore, as the ISG deceleration Dg decreases, the vehicle deceleration Dv quickly decreases by a predetermined amount Xc (symbol f1), and then the vehicle deceleration Dv gradually decreases (symbol f2).

As mentioned above, when the power generation torque Tg is reduced by a predetermined amount Xa (symbol b2), the vehicle deceleration Dv is also reduced by a predetermined amount Xc (symbol f1); It is set so as not to exceed the allowable amount Xd. That is, the predetermined amount Xa, which is the amount of decrease in the power generation torque Tg, is set so that the vehicle deceleration Dv does not decrease by exceeding the allowable amount Xd within the predetermined time Δt. Thereby, the power generation torque Tg can be quickly lowered without giving the occupant a great sense of discomfort, and preparation can be made for execution of anti-lock control. In other words, even if regenerative power generation is stopped due to anti-lock control, a sudden drop in vehicle deceleration Dv can be prevented, and anti-lock control can be executed without causing any discomfort to the occupants. I can do it.

As explained above, when the front and rear wheel speed difference ΔN exceeds the threshold value N2, it is expected that anti-lock control with regeneration stop will be executed afterwards, so the power generation torque Tg is quickly reduced by a predetermined value Xa. Afterwards, the power generation torque Tg is gradually reduced toward zero. As a result, the power generation torque Tg can be lowered before anti-lock control is executed, thereby avoiding a sudden drop in vehicle deceleration even if regenerative power generation is stopped due to execution of anti-lock control. be able to. In other words, the starter generator 17 can be appropriately controlled in preparation for executing the anti-lock control so as not to give the occupant a great sense of discomfort. Moreover, when the front and rear wheel speed difference ΔN exceeds the threshold value N2, the braking force of the wheels 21 and 23 can be reduced by quickly reducing the power generation torque Tg by the predetermined value Xa. can suppress slippage.

(Execution pattern 2)
FIG. 9 is a timing chart showing execution pattern 2 of power generation torque reduction control. FIG. 9 shows a situation where anti-lock control is executed by depressing the brake pedal 41 or the like before lowering the power generation torque Tg in preparation for executing anti-lock control. As shown at time t1b in FIG. 9, during deceleration traveling, the engine 12 is controlled to be in a fuel cut state (symbol a1), and the starter generator 17 is controlled to be in a regenerative power generation state (symbol b1). At this time, the power generation torque Tg is controlled at a predetermined value T1 (symbol b1), and the ISG deceleration Dg has reached the predetermined value D1 (symbol c1). Furthermore, the front and rear wheel speed difference ΔN is approximately zero (symbol d1), and the anti-lock control is stopped (symbol e1).

Subsequently, as shown at time t2b, when the front wheels 23 or the rear wheels 21 begin to rapidly slip due to brake operation on a frozen road surface, the front and rear wheel speed difference ΔN exceeds the threshold value N2 and reaches the threshold value N1 (sign d2), anti-lock control is started (symbol e2). As described above, when the anti-lock control is started (symbol e2), the engine control unit 81 of the main controller 80 switches the engine 12 from the fuel cut state to the fuel injection state (symbol a2). Further, when the anti-lock control is started (symbol e2), the ISG control unit 82 of the main controller 80 reduces the power generation torque Tg to a predetermined value T2 (symbol b2), and then reduces the power generation torque Tg to zero. (Symbol b3). At this time, as indicated by the symbol S3, the speed at which the power generation torque Tg is reduced to the predetermined value T2 (third speed) is lower than the rate at which the power generation torque Tg is reduced (first speed) indicated by the symbol S1 in FIG. It is also set too late. Note that, as indicated by symbols S3 and S4, the speed at which the power generation torque Tg is reduced to the predetermined value T2 is set faster than the speed at which the power generation torque Tg is subsequently reduced to zero.

In this manner, when switching the starter generator 17 from the regenerative power generation state to the power generation stop state in accordance with anti-lock control, the power generation torque Tg is gently lowered by the main controller 80 (symbols b2 and b3). Thereby, the ISG deceleration Dg can be gradually reduced (symbols c2, c3), and the vehicle deceleration Dv can be gradually reduced (symbols f1, f2). Moreover, since the power generation torque Tg gradually decreases (symbols b2, b3), the engine load caused by the starter generator 17 can be maintained in preparation for an increase in the engine speed Ne. That is, even in a situation where the engine speed Ne rises due to the restart of fuel injection associated with anti-lock control, the engine load from the starter generator 17 remains, so it is possible to suppress an excessive rise in the engine speed Ne. (Sign g1). In this way, it is possible to suppress the engine speed Ne from rising, so that the vehicle deceleration Dv is prevented from decreasing beyond the allowable amount Xd within the predetermined time Δt, that is, the vehicle deceleration Dv is lower than the line β. It can be suppressed to prevent rapid changes. As a result, even when fuel injection is restarted in conjunction with anti-lock control, it is possible to prevent a sudden drop in vehicle deceleration Dv, and anti-lock control can be executed without causing any discomfort to the occupants. be able to.

That is, as shown by the broken line α1 in FIG. 9, when the power generation torque Tg is rapidly reduced to zero due to anti-lock control, the ISG deceleration Dg is rapidly reduced to zero (symbol α2), Since the engine load from the starter generator 17 is eliminated, the engine rotational speed Ne increases significantly (symbol α3) and the vehicle deceleration Dv rapidly decreases (symbol α4) as fuel injection is restarted. On the other hand, the vehicle control device 10 gradually reduces the power generation torque Tg (symbols b2, b3) in accordance with the anti-lock control until the engine speed Ne stops rising (time t3b). The regenerative power generation state of the starter generator 17 is maintained. Thereby, it is possible to suppress an excessive increase in the engine speed Ne (sign g1), and it is possible to prevent a sudden drop in the vehicle deceleration Dv (signs f1, f2).

(Execution pattern 3)
FIG. 10 is a timing chart showing execution pattern 3 of power generation torque reduction control. FIG. 10 shows a situation where anti-lock control is executed by depressing the brake pedal 41 or the like in the process of reducing the power generation torque Tg in preparation for execution of anti-lock control. As shown at time t1c in FIG. 10, during deceleration traveling, the engine 12 is controlled to be in a fuel cut state (symbol a1), and the starter generator 17 is controlled to be in a regenerative power generation state (symbol b1). At this time, the power generation torque Tg is controlled at a predetermined value T1 (symbol b1), and the ISG deceleration Dg has reached the predetermined value D1 (symbol c1). Furthermore, the front and rear wheel speed difference ΔN is approximately zero (symbol d1), and the anti-lock control is stopped (symbol e1).

Subsequently, as shown at time t2c, when the front wheel 23 or the rear wheel 21 starts to slip and the front and rear wheel speed difference ΔN exceeds the threshold value N2 (symbol d2), the main controller 80 increases the power generation torque Tg by a predetermined amount Xa. After quickly decreasing the power generation torque Tg (symbol b2), the power generation torque Tg is gradually decreased toward zero. As a result, after the ISG deceleration Dg decreases by a predetermined amount Xb (symbol c2), the ISG deceleration Dg gradually decreases toward zero. Further, as the ISG deceleration Dg decreases, the vehicle deceleration Dv quickly decreases by a predetermined amount Xc (symbol f1), and then the vehicle deceleration Dv gradually decreases. As a result, similarly to the execution pattern 1 described above, the power generation torque Tg can be quickly lowered without giving the occupant a great sense of discomfort, and preparation can be made for execution of anti-lock control.

Next, as shown at time t3c, when the front wheels 23 or the rear wheels 21 begin to slip rapidly due to brake operation on a frozen road surface, the front and rear wheel speed difference ΔN reaches the threshold value N1 (symbol d3), and the anti-lock control is started. is started (symbol e2). As described above, when the anti-lock control is started (symbol e2), the engine control unit 81 of the main controller 80 switches the engine 12 from the fuel cut state to the fuel injection state (symbol a2). Moreover, when anti-lock control is started (symbol e2), the ISG control unit 82 of the main controller 80 reduces the power generation torque Tg toward zero (symbol b3). In the illustrated example, since the power generation torque Tg falls below the predetermined value T2 at time t3c, the power generation torque Tg gradually decreases toward zero (symbol b3).

In this manner, when switching the starter generator 17 from the regenerative power generation state to the power generation stop state in accordance with anti-lock control, the power generation torque Tg is gently lowered by the main controller 80 (symbol b3). Thereby, the ISG deceleration Dg can be gradually reduced (symbol c3), and the vehicle deceleration Dv can be gradually reduced (symbol f2). Moreover, since the power generation torque Tg gradually decreases (symbol b3), the engine load caused by the starter generator 17 can be maintained in preparation for an increase in the engine speed Ne. That is, even in a situation where the engine speed Ne rises due to the restart of fuel injection accompanying anti-lock control, the engine load caused by the starter generator 17 can remain, and it is possible to suppress the engine speed Ne from rising excessively. Therefore, it is possible to prevent a sudden drop in vehicle deceleration Dv (symbol f2).

That is, as shown by the broken line α1 in FIG. 10, when the power generation torque Tg is rapidly reduced to zero due to anti-lock control, the ISG deceleration Dg is rapidly reduced to zero (symbol α2), Since the engine load from the starter generator 17 is eliminated, the engine rotational speed Ne increases significantly (symbol α3) and the vehicle deceleration Dv rapidly decreases (symbol α4) as fuel injection is restarted. In contrast, in the vehicle control device 10, by gradually reducing the power generation torque Tg (symbol b3) in accordance with the anti-lock control, the starter generator 17 regenerative power generation state is maintained. Thereby, it is possible to suppress an excessive increase in the engine speed Ne (symbol g1), and it is possible to prevent a sudden drop in the vehicle deceleration Dv (symbol f2).

(flowchart)
Next, the execution procedure of the power generation torque reduction control by the main controller 80 will be explained according to a flowchart. FIG. 11 is a flowchart illustrating an example of an execution procedure of power generation torque reduction control. Note that "ISG" shown in FIG. 11 is the starter generator 17.

As shown in FIG. 11, in step S10, it is determined whether starter generator 17 is in a regenerative power generation state. If it is determined in step S10 that the starter generator 17 is in the regenerative power generation state, the process proceeds to step S11, where it is determined whether anti-lock control is being performed. If it is determined in step S11 that anti-lock control is not being performed, the process proceeds to step S12, where it is determined whether or not the front and rear wheel speed difference ΔN exceeds a threshold value N2.

In step S12, if it is determined that the front and rear wheel speed difference ΔN exceeds the threshold value N2, that is, if it is determined that a slight slip of the front wheels 23 or the rear wheels 21 has started, the process advances to step S13, and the anti-wheel speed difference ΔN exceeds the threshold value N2. It is determined whether lock control is being performed. If it is determined in step S13 that anti-lock control is not being performed, the process proceeds to step S14, where the power generation torque Tg of the starter generator 17 is lowered by a predetermined amount Xa at the speed (first speed) Sp1. In the subsequent step S15, if it is determined that anti-lock control is not being performed, the process proceeds to step S16, where the power generation torque Tg is lowered to zero at a speed (second speed) Sp2 slower than the speed Sp1. This allows the power generation torque Tg to be lowered before anti-lock control is executed, thereby avoiding a sudden drop in vehicle deceleration even if regenerative power generation is stopped due to anti-lock control execution. be able to. Moreover, since the braking force of the wheels 21 and 23 can be lowered by lowering the power generation torque Tg before the anti-lock control is started, slips of the front wheels 23 or the rear wheels 21 can be suppressed.

Further, if it is determined in each step S11, S13, and S15 that the anti-lock control is being executed, the process proceeds to step S17, and the power generation torque Tg is lowered to the predetermined value T2 at the speed (third speed) Sp3. In the following step S18, the power generation torque Tg is lowered to zero at a speed Sp4 that is slower than the speed Sp3. In this way, by gradually reducing the power generation torque Tg in conjunction with anti-lock control, it is possible to maintain the regenerative power generation of the starter generator 17 and suppress an excessive increase in engine speed, thereby preventing sudden vehicle deceleration. It is possible to prevent a major decline.

It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof. In the above explanation, when controlling the starter generator 17 to the regenerative power generation state, the power generation torque Tg of the starter generator 17 is controlled to a predetermined value T1, but the predetermined value T1 is a fixed value set in advance. It may be a variable value that changes depending on the vehicle speed, the amount of brake operation, etc. Furthermore, in the above description, the front and rear wheel speed difference ΔN obtained by subtracting the rear wheel rotation speed Nr from the front wheel rotation speed Nf is used as the rotation speed difference between the wheels 21 and 23, but the invention is not limited to this. The front and rear wheel speed difference may be obtained by subtracting the front wheel rotation speed Nf from the rear wheel rotation speed Nr. Further, as the front wheel rotation speed Nf, the rotation speeds detected by the left and right front wheel speed sensors 93 may be used, or the average value of the rotation speeds detected by the left and right front wheel speed sensors 93 may be used. Similarly, as the rear wheel rotation speed Nr, the rotation speeds detected by the left and right rear wheel speed sensors 94 may be used, or the average value of the rotation speeds detected by the left and right rear wheel speed sensors 94 may be used. good.

In the illustrated example, the starter generator 17, which is an ISG, is used as the generator, but the invention is not limited to this, and an alternator may be used as the generator, or a motor generator may be used as the generator. good. Further, in the illustrated example, the power supply circuit 50 is provided with two power storage bodies 51 and 52, but the present invention is not limited to this, and the power supply circuit 50 may be provided with only one power storage body. Further, in the illustrated example, the switch SW2 is provided on the positive electrode line 54 of the lithium ion battery 52, but the present invention is not limited to this. For example, as shown by the dashed line in FIG. 2, a switch SW2 may be provided on the negative electrode line 59 of the lithium ion battery 52.

10 Vehicle control device 11 Vehicle 12 Engine 17 Starter generator (generator)
21 Rear wheel (wheel)
23 Front wheel (wheel)
24 Power transmission path 40 Brake device (brake mechanism)
51 Lead battery (first electricity storage body)
52 Lithium ion battery (second electricity storage body)
81 Engine control section 82 ISG control section (power generation control section)
83 Brake control section ΔN Front and rear wheel speed difference (rotational speed difference)
Tg Power generation torque N1 threshold (first threshold)
N2 threshold (second threshold)
Sp1 speed (1st speed)
Sp2 speed (second speed)
Sp3 speed (3rd speed)

Claims (5)

A vehicle control device installed in a vehicle,
a generator connected to the wheels via a power transmission path;
a brake control unit that executes anti-lock control that controls a brake mechanism to suppress locking of the wheels when the rotational speed difference between the wheels exceeds a first threshold;
a power generation control unit that controls the generator to a regenerative power generation state during deceleration driving;
has
The power generation control unit controls the power generation torque of the power generator to a second level when the rotational speed difference exceeds a second threshold smaller than the first threshold while the power generator is controlled to a regenerative power generation state. After reducing the power generation torque at one speed, the power generation torque of the generator is reduced toward zero at a second speed slower than the first speed.
Vehicle control device. The vehicle control device according to claim 1,
an engine connected to the generator;
an engine control unit that controls the engine to be in a fuel cut state during deceleration traveling;
has
When the anti-lock control is executed during deceleration driving,
The engine control unit switches the engine from a fuel cut state to a fuel injection state,
When switching the generator from a regenerative power generation state to a power generation stop state, the power generation control unit maintains the regenerative power generation state until the engine speed stops increasing.
Vehicle control device. The vehicle control device according to claim 2,
The power generation control unit reduces the power generation torque of the power generator at a third speed slower than the first speed in the process of maintaining the regenerative power generation state of the power generator.
Vehicle control device. In the vehicle control device according to any one of claims 1 to 3,
The rotational speed difference is a rotational speed difference between the front wheels and the rear wheels.
Vehicle control device. In the vehicle control device according to any one of claims 1 to 4,
a first power storage body connected to the generator;
a second power storage body connected to the generator in parallel with the first power storage body;
A vehicle control device having:

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