JPH05199605A - Brake unit for motor vehicle - Google Patents

Abstract

PURPOSE:To ensure sufficient brake force while assuming failure of regenerative brake system in a vehicle in which a selection is made between hydraulic brake and regenerative brake based on the operation of brake pedal. CONSTITUTION:Power to be generated through regenerative brake is determined based on the outputs from a voltage sensor 201 and a current sensor 202 for a battery 1 and a decision is made that an abnormal state has occurred if the error between the actual power and theoretically estimated power of regenerative brake exceeds a predetermined value whereby selecting only hydraulic brake having high response and high brake force. A decision is also made that the regenerative brake system is abnormal if the output from the current sensor 202 has a negative value (discharge state) although regenerative torque is produced or if the output from the current has a positive value (charged state) although regenerative torque is not produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking system for an electric vehicle capable of selecting either one or both of hydraulic braking and regenerative braking based on the operation of a brake operator and the running state of the vehicle.

[0002]

2. Description of the Related Art Conventionally, as a braking device for such an electric vehicle, those disclosed in, for example, Japanese Patent Publication No. 56-6204 or Japanese Patent Publication No. 49-28933 are known.

[0003]

In an electric vehicle that uses both hydraulic braking and regenerative braking, it is desirable to use regenerative braking as much as possible from the viewpoint of improving energy recovery efficiency. When the braking system fails, it is desirable to use hydraulic braking having high responsiveness and large braking force. Particularly, when regenerative braking is preferentially selected in order to improve energy recovery efficiency, it is necessary to secure sufficient braking capacity assuming that the regenerative braking system should fail.

The present invention has been made in view of the above circumstances, and in an electric vehicle using both hydraulic braking and regenerative braking,
The purpose is to ensure sufficient braking capacity assuming a failure of the regenerative braking system.

[0005]

To achieve the above object, the present invention can select either or both of hydraulic braking and regenerative braking based on the operation of a brake operator and the running state of a vehicle. In a braking device for an electric vehicle, an abnormality determining means for comparing estimated power that can be generated by regenerative braking with actual power actually generated by regenerative braking, and making an abnormality determination when the difference exceeds a predetermined value, and The first feature is that the braking control means selects hydraulic braking based on the output of the abnormality determination means.

Further, the present invention provides a battery generated by regenerative braking in a braking device for an electric vehicle capable of selecting either one or both of hydraulic braking and regenerative braking based on the operation of a brake operator and the running state of the vehicle. A sensor that detects a charging current, an abnormality determining unit that makes an abnormality determination when the torque that can be generated by regenerative braking is a predetermined value or more and the battery charging current is negative, and based on the output of this abnormality determining unit. The second feature is that a braking control means for selecting hydraulic braking by means of a brake control means is provided.

Further, the present invention provides a battery generated by regenerative braking in a braking device for an electric vehicle capable of selecting either one or both of hydraulic braking and regenerative braking based on the operation of a brake operator and the running state of the vehicle. A sensor that detects a charging current, an abnormality determining unit that makes an abnormality determination when the battery charging current is positive when there is no torque generated by regenerative braking, and a braking that selects hydraulic braking based on the output of the abnormality determining unit. The third feature is that the control means is provided.

According to the present invention, in addition to any one of the above-mentioned first to third features, the abnormality judging means makes an abnormality judgment when the abnormal state is detected a plurality of times consecutively at a predetermined time interval. The fourth characteristic.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 28 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of an electric vehicle equipped with the braking device, FIG. 2 is a block diagram of a control system, and FIG. 3 is a braking mode. FIG. 4 to FIG. 28 are flowcharts, graphs and time charts for explaining the operation.

As shown in FIG. 1, this electric vehicle has a pair of front wheels Wf as driven wheels and a pair of rear wheels W as driving wheels.
In a four-wheeled vehicle provided with r, a rear wheel Wr is connected to an electric motor 2 that uses a battery 1 as an energy source via a transmission 3 and a differential 4 in four forward stages. A PDU (power drive unit) 5 is interposed between the battery 1 and the motor 2 to control the driving of the motor 2 by the battery 1 and to charge the battery 1 with the electric power generated by the motor 2 in association with regenerative braking. Control. The PDU
5 and transmission 3 are motor / mission control E
This motor is connected to a CU (electronic control unit) 6.
The mission control ECU 6 is connected to a brake ECU (electronic control unit) 7.

The master cylinder 9 operated by the brake pedal 8 is connected to an accumulator 11 that accumulates pressure by a hydraulic pump 10 via a modulator 12 and a brake cylinder 13f for each front wheel Wf and a brake cylinder 13r for each rear wheel Wr. Connected to. Modulator 12
Has a two-channel ABS (antilock brake system) control valve 14f for the front wheels and a one-channel ABS control valve 14r for the rear wheels, and when the front wheels Wf and the rear wheels Wr tend to lock, The brake hydraulic pressure transmitted to the brake cylinders 13f and 13r is reduced.

A brake cylinder 13f for the front wheel Wf is provided in an oil passage connecting the master cylinder 9 and the modulator 12.
A hydraulic control valve including an ON / OFF valve 15f for controlling the brake hydraulic pressure transmitted to the vehicle and a differential pressure valve 16f is different from the ON / OFF valve 15r for controlling the brake hydraulic pressure transmitted to the brake cylinder 13r of the rear wheel Wr. A hydraulic control valve composed of the pressure valve 16r is provided.

The ON / OFF valve 15f for the front wheels is a solenoid-driven normally open / closed valve, and shuts off the communication between the master cylinder 9 and the modulator 12 as required. The front wheel differential pressure valve 16f is provided in a bypass oil passage that bypasses the ON / OFF valve 15f, and has a valve element 18 biased in a valve closing direction by a spring 17f.
f and a linear solenoid 19f for adjusting the set load of the spring 17f. ON / OF for rear wheels
The F valve 15r and the differential pressure valve 16r have the same structure as that for the front wheels. A one-way valve that restricts hydraulic pressure transmission from the master cylinder 9 to the modulator 12 and allows hydraulic pressure transmission from the modulator 12 to the master cylinder 9 is interposed in the bypass oil passage.

As will be apparent by referring also to FIG.
The brake ECU 7 includes a battery voltage sensor 20 ₁ , a battery current sensor 20 ₂ , a battery remaining capacity meter 20 ₃ and a battery temperature sensor 20 provided in the battery ₁ .
₄ , a motor rotation speed sensor 22 for detecting the rotation speed of the motor 2, a wheel speed sensor 23 provided on the front wheels Wf and the rear wheels Wr, a brake pedal depression force sensor 24 ₁ provided on the brake pedal 8 and a brake. a pedal switch 24 _2, an accelerator opening sensor 25 provided on the accelerator pedal 28, a steering sensor 26 provided on the steering wheel 29, the accumulator 1
2 is connected to the accumulator pressure sensor 27, and the hydraulic pump 10 and the ON / OFF valve 15 are controlled based on their output signals.
f, 15r and differential pressure control valves 16f, 16r, and the ABS control valves 14f, 14r
And are connected.

The PDU 5 for controlling the battery 1 and the motor 2 and the transmission 3 are connected to a motor / mission control ECU 6 which operates by receiving a regenerative braking command and a mission shift command from the brake ECU 7. ..

Next, the outline of each braking mode will be described with reference to FIG.

Front wheels W in a vehicle equipped with this braking device
There are three types of braking modes for f and the rear wheel Wr: [mode 3], [mode 2], and [mode 1], and any one of them is selected by the initial determination to perform braking in a predetermined mode. , The mode is changed during braking according to the change in the operating state. [ Mode 3 ] This mode is selected in a normal operating state. That is, it is selected when the regenerative braking system is functioning normally, and neither during the hard braking nor during the steering. [Mode 3] is a mode in which the front wheel Wf is hydraulically braked and the rear wheel Wr is braked hydraulically and regeneratively. When the brake pedal 8 is depressed, only the rear wheel Wr is first regeneratively braked and the front wheel Wf is hydraulically braked. Not done
When the braking force of the rear wheel Wr reaches the break point P, hydraulic braking of the front wheel Wf is started from that moment. When the braking force of the rear wheel Wr exceeds the regenerative limit determined by various conditions of the battery 1 and the motor 2, the rear wheel Wr is braked by the combined use of regenerative and hydraulic pressure. When the braking force reaches the turning point Q, the braking force of the rear wheel Wr is weakened by the action of the well-known proportional pressure reducing valve provided inside the modulator 12, and finally, the braking force distribution characteristic as shown by the polygonal line OPQR is given. Be done.
This braking force distribution characteristic OPQR is biased above the ideal distribution characteristic shown by the broken line, that is, the braking force distribution of the rear wheels Wr is biased to exceed the ideal distribution characteristic, whereby regenerative braking of the rear wheels Wr is possible. The battery 1 is used to charge the battery 1 to extend the travelable distance per charge. However, in the above [mode 3], it is confirmed that the front wheel Wf is braked by the hydraulic pressure and the rear wheel Wr is braked by the combined use of the regenerative pressure and the hydraulic pressure for an extremely short time immediately after the start of braking, and there is no abnormality in the braking device during that period. Then, braking by hydraulic pressure is immediately stopped and the rear wheel Wr is braked only by regeneration. [ Mode 2 ] This mode is selected when the regenerative braking system is functioning normally and not during the hard braking but during the steering. Similar to [Mode 3] described above, this [Mode 2] is also a mode in which the front wheel Wf is braked by hydraulic pressure and the rear wheel Wr is braked by hydraulic pressure and regeneration. However, when the brake pedal 8 is depressed, hydraulic braking of the front wheels Wf is performed concurrently with regenerative braking of the rear wheels Wr, and if the braking force of the rear wheels Wr exceeds the regenerative limit during that time, the rear wheels Wr
Is braked by the combined use of regeneration and hydraulic pressure. When the braking force reaches the turning point R, the braking force of the rear wheel Wr is weakened by the proportional pressure reducing valve, and as a result, the polygonal line OQR showing the braking force distribution characteristic of [Mode 2] is closer to the front wheel than the ideal distribution characteristic shown by the broken line. The weight is given to the braking force of Wf. In this way, by selecting [Mode 2] during steering and simultaneously braking the front wheels Wf and the rear wheels Wr from the time of initial braking, it is possible to avoid deterioration of steering stability. [ Mode 1 ] This mode is selected at the time of sudden braking when the regenerative braking system does not function normally or when the regenerative braking system functions normally. In this [mode 1], regenerative braking of the rear wheels Wr is not performed, and both the front wheels Wf and the rear wheels Wr are hydraulically braked.
By performing only the hydraulic braking without performing the regenerative braking of the rear wheels Wr in this way, a slight delay occurs in responsiveness while transmitting the rotation of the rear wheels Wr to the motor 2 via the differential 4 and the transmission 3. The response of the braking force can be enhanced as compared with regenerative braking. Thus, the braking force distribution characteristic shown by the polygonal line OQR has a higher weighting on the braking force of the front wheel Wf than the ideal distribution characteristic shown by the broken line as in the above [Mode 2]. By selecting [Mode 1] during the sudden braking as described above, the braking response can be improved.

At the time of sudden braking during braking in the above [Mode 3], the change from [Mode 3] to [Mode 1] is performed. On the other hand, if the steering operation is performed during braking in [Mode 3], or if the tendency to lock the wheels on the low μ road is detected, [Mode 3]
From [Mode 2] to [Mode 2]
If a stronger wheel locking tendency due to a low μ road is detected during braking by, the [mode 2] to [mode 1]
Changes to. In this way, by selecting [Mode 2] or [Mode 1] depending on the road surface μ, it is possible to avoid deterioration of steering stability. The change from [Mode 3] to [Mode 2] or [Mode 1] is along an equal braking force line, that is, a line where the sum of the braking force of the front wheels Wf and the braking force of the rear wheels Wr is kept constant. Done by
This prevents a sudden change in the total braking force of the front and rear wheels Wf, Wr.

Next, the operation of the braking device having the above-mentioned structure will be described based on the flowchart of the main routine shown in FIG.

First, in step S100, various programs and data are stored in the storage devices of the brake ECU 7 and the motor / mission control ECU 6, and the braking device is initially set in an operable state. Continuing step S20
At 0, the battery voltage sensor 20 ₁ , the battery current sensor 20 ₂ , the remaining battery capacity meter 20 ₃ , the battery temperature sensor 20 ₄ , the motor speed sensor 22, the wheel speed sensor 23, the brake pedal depression force sensor 24 ₁ , the brake pedal switch. 24 ₂ , output signals of the accelerator opening sensor 25, the steering sensor 26, and the accumulator pressure sensor 27 are read into the brake ECU 7 (see FIG. 2).

In step S300, the limit value of the regenerative braking force that can be exerted at each moment is calculated based on the output signals of the various sensors. This regenerative braking force limit is determined by the state of the battery 1 and the state of the motor 2, and details thereof will be described later based on the subroutine of step S300.

In step S400, a regenerative braking force equivalent to engine braking is calculated. In a vehicle that uses an internal combustion engine as a driving power source, the engine brake operates when the depression force of the accelerator pedal is released, but in a vehicle that uses the motor 2 as a driving power source as in the present embodiment, the control equivalent to the engine brake is performed. By applying power to the rear wheels Wr by regenerative braking, a steering feeling similar to that of a normal vehicle having an internal combustion engine is provided. That is, when the pedal effort of the accelerator pedal 28 is weakened, the accelerator opening sensor 25
Accelerator opening detected by the motor and motor speed sensor 2
The braking force equivalent to the engine brake is calculated based on the motor rotation speed detected by 2 and the wheel speed detected by the wheel speed sensor 23, and the rear wheel Wr connected to the motor 2 is regenerated to obtain the braking force. Is braked. Then, the electric power generated by the motor 2 by the regenerative braking is used for charging the battery 1.

In step S500, the distribution ratio between the regenerative braking force and the hydraulic braking force is calculated. That is, the [Mode 3], [Mode 2], and [Mode 1] are selected based on the state of the braking operation and the steering operation by the driver, the friction coefficient of the road surface, and the like, and the [Mode 3] to [Mode 2] are selected. Alternatively, the mode change to [mode 1] is decided. And in each mode, the front wheel Wf
And the magnitudes of the regenerative braking force and the hydraulic braking force of the rear wheel Wr are calculated. The specific content of step S500 will be described later based on the subroutine.

In step S600, a shift position at which the regenerative braking force can be maximized is calculated, and the transmission 3 is automatically operated toward the shift position.
The specific content of step S600 will be described later based on the subroutine.

In step S700, the ON / OF of FIG. 1 is distributed so that the regenerative braking force and the hydraulic braking force are distributed at a predetermined ratio.
The F valves 15f and 15r and the differential pressure valves 16f and 16r are actually controlled. Thus, the electric power generated by the motor 2 by the regenerative braking of the rear wheel Wr is used to charge the battery 1. The specific content of step S700 will be described later based on the subroutine.

In step S800, antilock control is performed to prevent excessive slip of the front wheels Wf or the rear wheels Wr. That is, when it is detected by the output signal of the wheel speed sensor 23 that the wheel is about to enter the locked state, the ABS control valves 14f and 14r of FIG. 1 are controlled. As a result, the modulator 12 interposed between the master cylinder 9 and the brake cylinders 13f and 13r is actuated, and the brake cylinder 13 of the wheel having the lock tendency is actuated.
The brake hydraulic pressure transmitted to f and 13r is reduced to prevent the wheels from being locked.

In step S900, it is determined whether the braking device has failed. If it is determined that some kind of failure has occurred, the normally open ON / OFF valve 15f,
15r is held in the valve open position so that the master cylinder 9 and the modulator 12 directly communicate with each other. As a result, [Mode 1] is unconditionally selected, and the front wheels Wf and the rear wheels Wr are hydraulically braked as in a normal hydraulic braking system.

Next, the specific contents of step S300 (regenerative braking force limit value calculation) in the above-mentioned flowchart of FIG. 4 will be described with reference to FIGS.

As shown in the regenerative braking force limit value calculation routine of FIG. 5, first, in step S301, the limit value T _LMB of the regenerative braking force according to the state of the battery 1 is calculated, and in step S302, the regenerative braking force limit value T _LMB is regenerated. The braking force limit value T _LMN is calculated. The limit value T _LMB and the limit value T
The size of _LMN is compared in step S303 to determine the limit value T _{LM.
If B} is larger than the limit value T _LMN , step S3
04, the smaller limit value T _LMN is the regenerative braking force limit value T _LM
And the limit value T _LMB is less than or equal to the limit value T _LMN , the smaller limit value T is determined in step S305.
_LMB is selected as the regenerative braking force limit value T _LM . That is, the regenerative braking force limit value T _LM at that time is determined by the smaller one of the limit value T _LMB depending on the state of the battery 1 and the limit value T _LMN depending on the rotation speed of the motor 2.

Next, the sub-routine of step S301 (limit value calculation depending on the battery state) in FIG. 5 will be described with reference to FIG.

When it is detected in step S311 that the brake operation is performed by the output signal of the brake pedal depression force sensor 24 ₁ , the regeneration ON timer RBT starts counting in step S312. Then, in step S313, the depth of discharge (DOD) of the battery 1 is calculated based on the output signal of the battery remaining capacity meter 20 ₃ .

Subsequent Steps S314 to S318
Then, the limit value T _LMB0 is determined based on the size of the DOD. That is, when the value of DOD is small and the remaining capacity of the battery 1 is large, the limit value T _LMB0 is set small, and when the value of DOD is large and the remaining capacity of the battery 1 is small, the limit value T _{LMB0 is set.} Is set large. When this Figure 7 will be described in more detail with reference also to (A), when the DOD is relatively remaining capacity of the battery 1 to the threshold value D ₁ or less large, limit value T _LMB0
Is set to a relatively small limit value T _LMB1 . Also, DO
When D is equal to or greater than the threshold value D _{2 and} the remaining capacity of the battery 1 is relatively small, the limit value T _LMB0 is set to a relatively large limit value T _LMB3 . When the DOD is between the threshold value D ₁ and the threshold value D ₂ , the limit value T
_LMB0 is set to the limit value T _LMB2 between the T _LMB1 and T _LMB3 .

In the following step S319, the coefficient K ₁ for correcting the limit value T _LMB0 is determined based on the output signal of the battery temperature sensor 21. That is, the battery 1
Since the capacity of the battery temperature sensor 21 increases as the temperature rises, the output signal TEMP of the battery temperature sensor 21 as shown in FIG.
The temperature coefficient K ₁ is determined to increase linearly from _{1 as} the temperature exceeds TEMP ₀ .

Subsequent Steps S320 to S324
Then, the regeneration O counted by the regeneration ON timer RBT
The coefficient K ₂ for correcting the limit value T _LMB0 is determined based on the magnitude of the N time t. As is clear from also referring to FIG. 7C, when the regeneration ON time t, which is the elapsed time after the regenerative braking is started, is equal to or less than the threshold value t ₁ , the charging time coefficient K ₂ becomes 1. Is set. Regeneration ON time t
Is greater than or equal to the threshold t ₁ , the charging time coefficient K ₂ is set to K ₂₂ smaller than 1, and when the regeneration ON time t is greater than or equal to the threshold t ₂ , the charging time coefficient K ₂ is It is set to K ₂₁ , which is smaller than K ₂₂ . In this way, the charging time coefficient K ₂ becomes the maximum value 1 at the initial stage of charging when the battery 1 is efficiently charged, and the charging time coefficient K ₂ is from 1 to K ₂₁ , as the regeneration ON time t elapses. K ₂₂
Decrease to.

Thus, in step S325, the final regenerative braking force limit value T _LMB depending on the battery 1 becomes the limit value T _LMB0 by the DOD, the temperature coefficient K ₁ and the charging time coefficient K.
It is calculated by multiplying by ₂ .

The calculation of the regenerative braking force limit value T _LMB is performed every time the brake pedal 8 is stepped on.
When the pedaling force of is released, the regeneration O is performed in step S326.
The N timer is reset.

FIG. 8 shows step S of the flowchart of FIG.
This corresponds to 302 and shows a change in the limit value T _LMN of the regenerative braking force due to the output signal N _M of the motor rotation speed sensor 22. As is apparent from the figure, the limit value T _LMN linearly increased with the increase of the rotation speed N _M of the motor 1.
Eventually, it becomes almost constant and then decreases rapidly.

Next, the specific contents of step S500 (regeneration / hydraulic pressure distribution calculation) in the above-mentioned flowchart of FIG.
This will be described with reference to FIGS. 9 to 17.

As shown in the regenerative and hydraulic distribution determining routine of FIG. 9 and FIG. 10, first, the brake pedal switch 24 ₂ by the start of the braking operation is turned ON at step S501, the initial timer INT starts counting down in step S502. Then, in step S503, the initial flag INFL is set to "1" until the predetermined time elapses, and after the predetermined time elapses, the initial flag INFL is set to "0" (steps S503, S504, S50).
5). When the brake pedal switch 24 ₂ is turned off in step S501, the initial timer INT is reset in step S506.

Now, in step S507, the mode 1 flag is "0" and [mode 1] is not selected, and in step S508 the regenerative braking system is not in failure, and in steps S509 and S510. Not during sudden braking, and because the road surface μ is sufficiently large in steps S511 and S512 and the wheels do not tend to lock, as a result, the time differential value ΔV _W of the wheel speed calculated from the output signal of the wheel speed sensor 23 (wheel speed Is a predetermined threshold value g ₁ , g ₂ (g ₁ > g)
₂ ) or less, and both the temporary mode 2 flag M2FL ′ and the mode 2 flag M2FL are “0” in step S513 and step S514, and [mode 2] is not selected, and step S515 and step S5
When the steering flag STRFL is not set to "1" in 16 and the steering is not performed, step S517 is performed.
[Mode 3] is selected with. Then, the step S
If the mode 1 flag is set to "1" in 507, [mode 1] is selected in step S518,
If the mode 2 flag M2FL is set to "1" in step S514, [mode 2] is selected in step S519.

The mode 1 flag which determines the selection of [mode 1]
For the lag M1FL, one of the following conditions is satisfied:
Is set to "1" in step S520. In step S508, the regenerative braking system fails
If In steps S509 and S510,
When it is determined to be a brake. In step S511, the time differential value ΔV of the wheel speed_W
The larger the threshold g ₁If it exceeds. (G₁Through
Even if the braking force distribution of the usual hydraulic braking device approaches the lock
It is selected as an estimated value) In step S512, the time differential value ΔV of the wheel speed_W
The larger the threshold g ₁And the smaller threshold g₂of
If it is between (g₂Is the braking force distribution of a normal hydraulic braking system
Select as a value estimated that the lock will be released by returning to
Mode), and in step S521, the mode 2
If the lag is M2FL is set to "1".

In addition, a temporary mode for determining the selection of [Mode 2].
Mode 2 flag M2FL 'is set when the following conditions are met.
Is set to "1" in step S527, and
Do 2 flag M2FL satisfies the following conditions or
Is set to "1" in step S522. In step S512, the time differential value ΔV of the wheel speed_W
The smaller threshold g ₂And step
In step S521, the mode 2 flag is set to M2FL to "1".
Not done (ie [mode 3] is selected
State), and step S523 and step S52
If the M2 delay timer M2T is counting down at 4,
Go. In steps S523 and S524, the M2 delay
Imma M2T is counting down (that is, M2FL '=
1) In step S512, the wheel speed time differential value ΔV_W
The smaller threshold g₂When it becomes below, or M
When the predetermined time by the 2-delay timer M2T has elapsed
Go. It should be noted that the M2 delay timer M2T has passed a predetermined time.
Even after the error, ΔV in step S512_W> G₂Judgment
If turned off, [Mode 1] is selected according to the above conditions
To be done. In steps S515 and S516,
When it is determined that the tearing is in progress.

When it is determined in step S501 that the brake is not being operated, that is, when the depression force of the brake pedal 8 is released, the mode 2 flag M2FL and the mode 1 flag M1FL are both set to "0" for the first time in step S528 and step S529. Is set to. Therefore,
[Mode 2] or [Mode 1] once during one braking
Is selected, there is no reverse transition from [Mode 2] or [Mode 1] to [Mode 3] during the braking.

Next, details of step S509 (judgment of sudden braking) of FIG. 9 will be described with reference to the flowchart of FIG. If the pedal effort F _B detected by the brake pedal pedal force sensor 24 ₁ is greater than or equal to a predetermined threshold value in step S531, it is unconditionally determined to be sudden braking, and the rapid braking flag is “1” in step S532.
Is set to.

On the other hand, when the pedaling force F _B is less than the predetermined threshold value and the sudden braking determination timer PTM is at the initial value t ₀ at the start of counting in step S533, the pedaling force F _B at that time is determined in step S534. Initial pedal force F _B1 . In the following step S535, the sudden braking determination timer P
When TM is not counted down to 0, the countdown is performed in step S536, and
In step S537, the sudden braking flag is set to "0".

In step S535, the sudden braking judgment
When Imma PTM is counted down to 0
Fixed time t₀Is passed, then at step S538
Pedaling force F_BIs t₀Rear tread force t_B2And step S53
In 9 the sudden braking judgment timer PTM is t₀Is reset to
It Then, in subsequent step S540, t₀Rear tread force t _B2
 Initial pedaling force F_B1Difference is the pedal effort change threshold ΔF_BCompared to
And the difference is the pedal effort change threshold ΔF._BAbove
The sudden braking flag is set to "1" in step S532.
If it is not exceeded, a sudden break occurs in step S537.
The flag is set to "0".

As described above, when the pedaling force F _B exceeds the first threshold value and when the increase amount of the pedaling force F _B within the predetermined time exceeds the second threshold value, the braking is sudden. Is determined.

Next, the details of step S515 (steering condition determination) of FIG. 10 will be described with reference to the flowchart of FIG. 12 and FIG.
This will be described with reference to the graph of No. 3. The vehicle speed V calculated from the output signal of the wheel speed sensor 23 is the maximum threshold value V ₃
When larger than the steering flag STRFL is set to "1" when the steering angle detected by the steering sensor 26 theta is greater than the smallest threshold theta _1, a steering flag S when the threshold theta ₁ below
TRFL is set to "0" (step S541,
S542, S543, S544, S545, S546).

When the vehicle speed V is between the maximum threshold value V ₃ and the smaller threshold value V ₂ , the steering flag STRFL is "1" when the steering angle θ is larger than the intermediate threshold value θ _2. ”, The steering angle θ is the threshold θ
_{When it is 2} or less, the steering flag STRFL is set to "0" (steps S541, S542, S54).
3, S547, S545, S546).

When the vehicle speed V is between the threshold value V ₂ and the minimum threshold value V ₁ , the steering flag STRF is set when the steering angle θ is larger than the maximum threshold value θ _3.
When L is set to "1" and the steering angle θ is equal to or smaller than the threshold value θ ₃ , the steering flag STRFL is set to "0" (steps S541, S542, S548, S54).
5, S546).

When the vehicle speed V is equal to or smaller than the minimum threshold value V ₁ , the steering flag ST is set regardless of the steering angle θ.
RFL is set to "0" (steps S541, S
546).

As described above, when the vehicle speed V is high, it is determined that the steering is being performed even if the steering angle θ is small, and when the vehicle speed V is low, it is determined that the steering is being performed unless the steering angle θ is large. I will not be defeated.

Details of step S517 (mode 3 distribution determination) in FIG. 10 will be described below with reference to the flowchart in FIG. 14 and the graph in FIG. In step S551, the regenerative braking force limit value T _LMLM calculated in tire torque is calculated by multiplying the regenerative braking force limit value T _LM obtained in step S300 of FIG. 4 by the gear ratio R (n) of the nth speed. To be done. In the following step S552, the pedaling force F corresponding to the break point P (the point where the hydraulic braking of the front wheels Wf is started in [Mode 3]) in the braking force distribution characteristic of FIG. 1 based on the graph of FIG. 17 (A). _B0 is searched.

In step S553, the converted regenerative braking force T _RG corresponding to the pedal effort F _B is calculated based on the graph of FIG. 17B.
Will be searched. In a succeeding step S554, the Fr offset amount, that is, the operation amount of the linear solenoid 19f in FIG. 1 is calculated by multiplying the _breaking pedal force F _B0 by a constant. In step S555, the Rr offset amount, that is, the operation amount of the linear solenoid 19r of FIG. 1 is searched based on the graph of FIG. Continued Step S5
At 56, the initial flag INFL (step S504 of FIG. 9,
If S1) is set to "1", that is, if a predetermined time has not elapsed from the start of braking,
In step S557, the ON / OFF valve 15f of FIG.
Both the Fr offset flag and the Rr offset flag that control 15r are set to "0" (valve open). on the other hand,
If the initial flag INFL is set to "0" in step S556, that is, if a predetermined time has elapsed from the start of braking, both the Fr offset flag and the Rr offset flag are set to "1" (valve closed in step S558). ) Is set.

Details of step S519 (mode 2 distribution determination) of FIG. 10 will be described below with reference to the flowchart of FIG. 15 and the graph of FIG. In step S561, the converted regenerative braking force limit value T _RGLM converted into tire torque is calculated by multiplying the regenerative braking force limit value T _LM obtained in step S300 of FIG. 4 by the gear ratio R (n) of the nth speed. It In the following step S562, in FIG.
The converted regenerative braking force T _RG is searched based on the graph of 7 (D).

In step S563, the Fr offset amount is set to 0. This is because the braking force distribution characteristic of [Mode 2] in FIG. 1 does not have the breaking point P, and the hydraulic braking of the front wheels Wf is performed from the time of initial braking. Continuing step S
At 564, the Rr offset amount, that is, the operation amount of the linear solenoid 19r of FIG. 1 is searched based on the graph of FIG. Then, in step S565, the Fr offset flag for controlling the ON / OFF valve 15f on the front wheel side in FIG. 1 is set to "0" (open valve), and the O on the rear wheel side is set.
The Fr offset flag for closing the N / OFF valve 15r is set to "1" (closed).

Details of step S518 (mode 1 distribution determination) in FIG. 10 will be described below with reference to the flowchart in FIG. Since regenerative braking is not performed in this [mode 1], the converted regenerative braking force T _RG is calculated in step S571.
Is set to 0. In subsequent steps S572 and S573, both the Fr offset amount and the Rr offset amount are set to 0. Finally, in step S574, both the Fr offset flag and the Fr offset flag are "0" (open valve).
The hydraulic pressure generated by the master cylinder 9 is directly transmitted to the modulator 12, and the front wheels Wf and the rear wheels Wr are braked by the normal hydraulic pressure.

Next, details of step S600 (shift command) in FIG. 4 will be described with reference to the flowcharts in FIGS.
A description will be given based on the graph of No. 1 and the time chart of FIG.

If the shift is in progress in step S601 of the flowcharts of FIGS. 18 to 20, the shift flag SHFL is set to "1" in step S602, and then the converted regenerative braking force T _RG is set to 0 in step S603.
And the Fr offset flag and the Rr offset flag are both set to "0" (valve open) in step S604. As a result, the regenerative braking is not performed during the shift, and the front wheels Wf and the rear wheels Wr are braked by the normal hydraulic pressure.

When the shift flag SHFL is set to "1" in step S605 even though the shift is not in progress in step S601, it is determined that the shift is completed, and in the subsequent step S606, the front wheels Wf and the rear wheels Wr. The hydraulic braking of step S6 is released, and step S6 is performed.
At 07, the shift flag SHFL is set to "0".

If the steering flag STRFL is set to "1" while the steering is being performed in step S608, the shift command described later is not issued.

In subsequent steps S609 to S613, the estimated regenerative electric power E _(n) at the current shift position n is calculated. That is, in step S609, the converted regenerative braking force T
The motor torque T _{MT (n) at the} nth speed is calculated by dividing _RG by the gear ratio R _(n) . Then, in step S612, based on the graph of FIG. 21, the motor efficiency η is calculated from the motor torque T _{MT (n)} and the rotation speed N _{M of the} motor 2.
_(n) is obtained, and in the subsequent step S613, the motor efficiency η _(n) is added to the motor torque T _{MT (n)} and the rotation speed N of the motor 2.
By multiplying by _M , the estimated regenerative electric power E _{(n) at the} shift position n is calculated.

Next, in steps S614 to S622, the estimated regenerative electric power E _(n-1) when downshifting from the current shift position is calculated. That is, step S
If the current shift position n is the 1st speed at 614, the downshift is substantially impossible, and thus step S6 is performed.
The estimated regenerative electric power E _(n-1) in the case of downshifting at 15 is set to 0. On the other hand, when the current shift position n is any one of the 2nd speed to the 4th speed in step S614, the estimated regenerative electric power E ₍ in the case of downshifting to the n-1th speed in steps S616 to S622 as described above _{). n-1)} is calculated. At that time, in step S617, the motor torque T
_{When MT (n-1)} exceeds the regenerative braking force limit value T _LM ,
In step S618, the regenerative braking force limit value T _LM is set to the motor torque T _{MT (n -1)} . In the case of downshifting, in step S619, the rotational speed N _{M (n-1)} of the motor 2 at the time of downshifting is the gear ratio R _(n) , R _(n-1) and the rotational speed N _{M (} n _n) , and as a result, if the number of revolutions N _{M (n-1)} is overrev in step S620, the estimated regenerative power E _{(n-1 )} is estimated in step S615.
₎ Is set to 0.

Next, in steps S623 to S630, the estimated regenerative electric power E _{(n + 1)} when shifting up from the current shift position is calculated. That is, step S
If the current shift position n is the fourth speed at 623, upshifting is substantially impossible, so step S6
The estimated regenerative electric power E _{(n + 1)} when shifting up in 24 is set to 0. In subsequent steps S625 to S630, the estimated regenerative electric power E _{(n + 1)} in the case of upshifting is calculated as described above. At that time, when the motor torque T _{MT (n + 1)} exceeds the regenerative braking force limit value T _LM in step S626, the regenerative braking force limit value T _LM motor torque T _MT at step S627 _{(n + 1)} It should be noted that, in the case of the shift up, no overrev is generated, so the determination of the overrev performed in the case of the shift down is not performed.

Thus, in steps S631 to S633, the current estimated regenerative power E _(n) , the estimated regenerative power E _(n-1) in the case of downshifting, and the estimated regenerative power E _{(n +} in the case of upshifting ₎ . The three parties of ₁₎ are compared, and if E _(n-1) is the maximum, a downshift command is issued in step S634, and conversely, if E _{(n + 1)} is the maximum, step S is performed.
A shift up command is issued at 635.

The above shift operation will be described with reference to the time chart of FIG. For example, suppose that the pedaling force of the brake pedal 8 is operated so as to gradually increase at times T ₁ , T ₃ , and T ₈ , and a regenerative braking command is issued at time T ₂ .
At this time, when it is determined to shift down the shift position from, for example, the third speed to the second speed in order to maximize the regenerative energy, the clutch is released at time T ₄ .

[0068] Since the clutch is regenerative braking force impossible disconnected will be the the rear wheel Wr and the motor 2 release, time T ₄
The regenerative braking command of the motor 2 is canceled from T ₇ to T ₇ . Then, while regenerative braking is not performed, that is, from time T ₄ to T ₇ , a hydraulic brake command is issued and hydraulic braking is replaced with regenerative braking. And Thus, at time T ₅ in the disengagement period of the clutch from time T ₄ to T _6, a shift command is issued downshifting from the third speed to the second speed is executed.

As described above, the total braking force is
T₂~ T_FourThen, due to regenerative braking, time T_Four~ T₇Then oil
Time T due to pressure braking₇~ T₉With regenerative braking,
Tick T ₉After that, it is secured by using both regenerative braking and hydraulic braking.
It

Details of step S700 (regeneration / hydraulic braking force control) in FIG. 4 will be described below with reference to the flowchart in FIG.

First, in step S701, the converted regenerative braking force T _RG is output. And as is clear from FIG.
In [Mode 3] and [Mode 2], the rear wheel Wr is regeneratively braked so that the converted regenerative braking force T _RG is obtained at the time of initial braking, and the electric power generated by the motor 2 by this regenerative braking is used to charge the battery 1. Be served. Step S702
And S703, in steps S554 and S555 of FIG. 14 corresponding to [mode 3], steps S563 and S564 of FIG. 15 corresponding to [mode 2], and steps S572 and S573 of FIG. 17 corresponding to [mode 1]. The determined Fr offset amount and Rr offset amount are output. As a result, the linear solenoids 19f, 1 of the hydraulic control valves for the front wheels Wf and the rear wheels Wr shown in FIG.
9r operates and the set load of the springs 17f and 17r of the differential pressure valves 16f and 16r is adjusted to a predetermined magnitude.

In the subsequent step S704, if the Fr offset flag is not set to "1" ([mode 2]
And in the case of [mode 1]), in step S705
If the N / OFF valve 15f is kept open and is set to "1" (in the case of [mode 3]),
In step S706, the ON / OFF valve 15f is closed.

Therefore, in [mode 2] and [mode 1] in which the ON / OFF valve 15f is kept open, the brake hydraulic pressure generated by the master cylinder 9 is directly transmitted to the modulator 12, and the [mode] in FIG. 2] and [mode 1], the front wheels Wf are hydraulically braked from the initial braking time, as shown in the braking force distribution characteristics.

On the other hand, in [mode 3], the ON / OFF valve 15f is closed, so the brake hydraulic pressure generated by the master cylinder 9 is blocked by the ON / OFF valve 15f and passed through the differential pressure valve 16f. Modulator 1
2, the differential pressure valve 16f does not open until the pedaling force of the brake pedal 8 increases to a predetermined value due to the set load of the spring 17f. As a result, as shown by the line segment OP in the braking force distribution characteristic of [mode 3] in FIG. 1, the hydraulic braking force is prevented from acting on the front wheels Wf during the initial braking. When the brake hydraulic pressure generated by the master cylinder 9 reaches a magnitude corresponding to the break point P,
The differential pressure valve 16f opens and the hydraulic braking force starts to act on the front wheels Wf.

Returning to the flowchart of FIG. 23, if the Rr offset flag is not set to "1" in step S707 (in the case of [mode 1]), step S70.
If the ON / OFF valve 15r is kept open in step 8 and is set to "1" (in the case of [mode 3] and [mode 2]), it is turned on / off in step S709.
The F valve 15r is closed.

Therefore, in [Mode 1] in which the ON / OFF valve 15r is kept open, the brake oil pressure generated by the master cylinder 9 is directly transmitted to the modulator 12, and the [Mode 1] in FIG. ], The rear wheels Wr are hydraulically braked from the time of initial braking.

On the other hand, in [mode 3] and [mode 2], since the ON / OFF valve 15r is closed, the brake hydraulic pressure generated by the master cylinder 9 is ON / O.
It is blocked by the FF valve 15r and transmitted to the modulator 12 via the differential pressure valve 16r, and the differential pressure valve 16r does not open until the pedaling force of the brake pedal 8 increases to a predetermined value by the set load of the spring 17r. ..
As a result, the hydraulic braking force is prevented from acting on the rear wheel Wr up to the regeneration limit in the braking force distribution characteristics of [mode 3] and [mode 2] in FIG. When the brake hydraulic pressure generated by the master cylinder 9 reaches a level corresponding to the regenerative limit, the differential pressure valve 16r opens and hydraulic braking force starts to act on the rear wheel Wr, and thereafter, regenerative power is applied to the rear wheel Wr. The braking force and the hydraulic braking force act.

As described with reference to the flow charts of FIGS. 9 and 10, [Mode 3] is first selected as normal braking at the start of braking, and at that time, there is a failure of the regenerative braking system, sudden braking, steering or the like. When a special state is detected, the operation shifts from [mode 3] to [mode 1] or [mode 2]. However, if only regenerative braking of the rear wheels Wr is performed immediately after the start of braking in [mode 3], it corresponds to the rise time of hydraulic pressure when shifting to [mode 1] or [mode 2] in which hydraulic braking is performed. There may be a delay in response. In order to prevent this, as shown in steps S502 to S505 in FIG. 9, the initial flag INFL is set to "1" within a very short predetermined time until the initial timer INT, which starts counting down at the same time as the start of braking, times up. As a result, both the Fr offset flag and the Rr offset flag are set to "0" as shown in steps S556 and S557 of FIG. Therefore, within a predetermined time immediately after the start of braking, in addition to the normal regenerative braking of the rear wheel Wr in [Mode 3], hydraulic braking of the front wheel Wf and the rear wheel Wr by opening the ON / OFF valves 15f and 15r is simultaneously performed. Will be seen.

[Mode 3] immediately after the start of braking.
When shifting from the state of [1] to [Mode 1] or [Mode 2], the hydraulic braking can be started without delay and a delay in braking response can be avoided. When [Mode 3] is selected as it is, the temporary hydraulic braking is stopped after the initial timer INT has timed out, and the rear wheel Wr is regeneratively braked by [Mode 3]. is there.

When the brake pedal 8 is depressed from the accelerated state to perform braking, the rear wheel Wr is transmitted from the motor 2 via the transmission 3, the differential 4, and the drive shaft.
Due to the play and the twist existing in the power transmission system that transmits the driving force, a slight response delay occurs before the regenerative braking actually starts to work. However, as described above, by performing the hydraulic braking at the same time when the brake pedal 8 is depressed, the response delay of the regenerative braking can be minimized.

Details of step S900 (failure determination) of FIG. 4 will be described below with reference to the flowcharts of FIGS. 24 to 26 and the graphs of FIGS. 27 and 28.

Step S90 of the flowchart of FIG.
1, the failure flag FAILFL has not occurred (see step S508 in FIG. 9).
There if not set to "1", the fail of the regenerative braking system in the subsequent step S902～S908, the brake pedal depression force sensor 24 ₁ fail, fail the steering sensor 26, the fail of the wheel speed sensors 23, ABS control valves 14f, 14r fail, hydraulic control valve, that is, ON / OFF valve 15f, 15r
And the failure of the differential pressure valves 16f and 16r and the failure of the hydraulic pump 10 are sequentially determined.

Next, the subroutine of step S902 (regeneration fail determination) of FIG. 24 will be described with reference to the flowchart of FIG.

First, in step S911, the actual regenerated electric power E _RG generated by the motor 2 is compared with the battery voltage sensor 20 ₁
Calculating by multiplying the output signal V _B and the battery current sensor 20 _{and second} output signals I _B. Continued Step S9
12, S913, the above-described step S613 of FIG.
Whether or not the actual regenerative power E _RG exists between two values obtained by adding and subtracting a predetermined value α to the estimated regenerative power E _(n) calculated in step 1, that is, between E _(n) + α and E _(n) −α. Is judged. That is, when the actual regenerative power E _RG and the estimated regenerative power E _(n) are in the shaded area in FIG. 27, it is determined that the regenerative braking system is abnormal.

In the case where the above-mentioned abnormality judgment is made first, in step S914, the temporary fail flag FAILFL '.
Is not set to "1", step S91
At 5, the temporary fail flag FAILFL 'is set to "1". When it is determined in the next loop that the regenerative braking system is abnormal again, that is, when the temporary fail flag FAILFL 'is set to "1" in step S914, the fail flag FAILFL is finally set to "1" in step S916. It is set to 1 ”. When it is determined in steps S912 and S913 that the regenerative braking system is normal, steps S917 and S91 are performed.
In step 8, the temporary fail flag FAILFL 'and the fail flag FAILFL are set to "0", and step S9 is executed.
If the temporary fail flag FAILFL is set to "1" in 15, the fail flag F is set in step S918.
AILFL is set to "0".

[0086] Compared estimated regenerative electric power E as described above and _(n) the actual regenerative power E _RG, when the actual regenerative power E _RG is determined that there is an abnormality an excessive or too small beyond the predetermined value A temporary fail flag FAILFL 'is set, and if the abnormality is continuously detected in the next loop, the fail flag F is detected.
By setting AILFL, it is possible to reliably determine the failure of the regenerative braking system without being affected by radio wave interference or the like.

Next, the subroutine of step S903 (brake pedal depression force sensor failure determination) of FIG. 24 will be described with reference to the flowchart of FIG.

First, in steps S921 and S922, it is determined whether or not the output signal of the brake pedal depression force sensor 24 ₁ is between 0.4V and 4.6V. As shown in the graph of FIG. 28, the output V _FB of the brake pedal tread force sensor 24 ₁ changes from 0.5 V to 4. V as the tread force F _B increases.
It is set so as to increase linearly up to 5V and then be maintained at a constant value of 4.5V. Since the error of the brake pedal depression force sensor 24 ₁ is within an allowable range of ± 0.1 V, if the brake pedal depression force sensor 24 ₁ is normal, the output V _FB has a minimum value of 0.4 V and a maximum value of 4 V. Should be between .6V. However, in steps S921 and S922, the output V _FB changes from 0.4V to 4.6.
If it is not within the range of V, the brake pedal depression force sensor 2
It is judged that 4 ₁ is abnormal.

In the case where the above-mentioned abnormality judgment is made first, and in step S923, the temporary fail flag FAILFL '.
Is not set to "1", step S92
At 4, the temporary fail flag FAILFL 'is set to "1". When it is determined again in the next loop that the brake pedal depression force sensor 24 ₁ is abnormal, that is, when the temporary fail flag FAILFL ′ is set to “1” in step S923, the fail flag is finally set in step S925. FAILFL is set to "1".

Further, although the brake pedal switch 24 ₂ is not turned on in step S926, that is, the brake pedal 8 is not operated, the brake pedal depression force sensor 24 is operated in step S927.
_If the output V _{FB of 1} exceeds 0.6 V, it is determined that the brake pedal depression force sensor 24 ₁ has an abnormality, and the process proceeds to step S923.

Then, steps S921, S922, S
If it is determined in 926 and S927 that the brake pedal depression force sensor 24 ₁ is normal, steps S928,
In step S929, the temporary fail flag FAILFL 'and the fail flag FAILFL are set to "0", and the brake pedal switch 24 ₂ is turned on in step S926, and the temporary fail flag FAILF in step S924.
If L is set to "1", step S929
Then, the fail flag FAILFL is set to "0".

As described above, operate the brake pedal 8
If the brake pedal pedal force sensor 24₁Output V_FB
Indicates an impossible value (0.4 V or less and 4.6 V or more)
The brake pedal and when the brake pedal is not operated.
Rake pedal force sensor 24 ₁Output V_FBCannot be
When the value (0.6V or more) is displayed, it is judged that there is an abnormality.
Therefore, the brake pedal pedal force sensor 24₁Output error
Not only the brake pedal depression force sensor 24₁Sticking
It is possible to reliably detect a trouble caused by. Only
Also using the temporary fail flag FAILFL '
Is detected continuously, make a final abnormality judgment
Brakes without being affected by radio interference.
Pedal force sensor 24₁The fail of
You can

FIG. 29 shows another embodiment in which the regenerative / hydraulic pressure distribution determining routine shown in FIGS. 9 and 10 is simplified.

In this embodiment, when the regenerative braking system is not out of order, the steering is not being performed, the pedaling force is not more than the threshold value, and the road surface μ is not low, the normal [mode 3] is set. Selected (steps S581 and S5)
82, S583, S584, S585, S586, S5
87).

If the regenerative braking system is out of order in step S581, then [mode 1] is unconditionally selected in step S589. Also, step S5
82, S583, when it is determined that the steering is being performed, when it is determined that the pedaling force is equal to or more than the threshold value and the braking is suddenly performed in step S584, or step S584.
When it is determined in 585 and S586 that the road surface μ is low and the wheels may be locked, [Mode 2] is selected in step S588.

FIG. 30 shows step S582 of FIG.
This shows a subroutine of (steering condition determination). When the lateral acceleration of the vehicle is equal to or greater than the reference value in step S591, it is determined that the vehicle is in the stelling state and step S5 is executed.
In step 92, the steering flag STRFL is set to "1", and when it is less than the reference value, it is determined that the steering is not being performed, and in step S593 the steering flag STR is set.
FL is set to "0". Incidentally, the step S59
In 1, it is possible to determine the steering condition using the yaw rate r of the vehicle as a parameter instead of the lateral acceleration of the vehicle.

FIG. 31 shows another embodiment of the regenerative fail judging routine shown in FIG.

First, in step S931, the tire
The converted regenerative braking force T converted into lux_RG(Figure 14
(See step S556 and step S562 in FIG. 15)
Is the standard corresponding to the maximum power consumed by the electrical load
Converted regenerative braking force T_RG0Compared to. Converted regenerative braking force T
_RGIs the standard conversion regenerative braking force T_RG0Over regenerative power
If the load can be compensated, the buffer is added in step S932.
Battery current sensor 20 ₂Current value I output_BThe sign of
to decide. The current value I_BIs negative and is originally charged
If battery 1 should be discharged, it is determined to be abnormal.
Refused, in steps S933, S934, S935
Similarly to the above, the temporary fail flag FAILFL ′ and
The operation of the fail flag FAILFL is performed.

When the above-mentioned steps S931 and S932 are normal, the routine proceeds to step S936, where the converted regenerative braking force T _RG is 0 and regenerative braking is not performed, but the current is rewritten at step S937. When the value I _B is positive and the battery 1 is being charged, it is also determined that there is an abnormality, and the process proceeds to step S933. The temporary fail flag FAILFL 'and the fail flag FAILFL in steps S938 and S939.
Is reset by the steps S917 and S9 of FIG.
Same as 18.

Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various small design changes can be made.

For example, in the embodiment, the vehicle in which the front wheel Wf is the driven wheel and the rear wheel Wr is the driving wheel has been illustrated, but the present invention is applied to the vehicle in which the front wheel Wf is the driving wheel and the rear wheel Wr is the driven wheel. However, it is applicable.

[0102]

As described above, according to the first feature of the present invention, the estimated electric power to be generated by the regenerative braking is compared with the actual electric power actually generated by the regenerative braking, and the difference exceeds a predetermined value. In this case, the abnormality determination is made, so that the failure of the regenerative braking system can be accurately determined. Moreover, since hydraulic braking is selected when a failure of the regenerative braking system is determined, it is possible to secure a quick braking response and a sufficient braking force.

Further, according to the second feature of the present invention, when the torque that can be generated by regenerative braking is equal to or greater than a predetermined value and the battery charging current detected by the sensor is negative, the abnormality determination is made. Therefore, the failure of the regenerative braking system can be accurately determined. Moreover, since hydraulic braking is selected when a failure of the regenerative braking system is determined, it is possible to secure a quick braking response and a sufficient braking force.

Further, according to the third feature of the present invention, the abnormality judgment is made when the battery charging current detected by the sensor is positive when there is no torque generated by the regenerative braking. The failure can be accurately determined. Moreover, since hydraulic braking is selected when a failure of the regenerative braking system is determined, it is possible to secure a quick braking response and a sufficient braking force.

Further, according to the fourth aspect of the present invention, since the abnormality determination is made when the abnormal state is detected a plurality of times consecutively at the predetermined time interval, it is possible to avoid the influence of the radio wave interference or the like and to make it more reliable. It is possible to make various abnormality determinations.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electric vehicle including a braking device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control system

FIG. 3 is a schematic explanatory diagram of a braking mode.

FIG. 4 is a flowchart of a main routine.

FIG. 5 is a flowchart of a subroutine corresponding to step S300 of the main routine.

6 is a flowchart of a subroutine corresponding to step S301 of FIG.

7 is a graph accompanying the flowchart of FIG. 6;

FIG. 8 is a graph accompanying the flowchart of FIG.

FIG. 9 is a flowchart of a subroutine corresponding to step S500 of the main routine.

FIG. 10 is a flowchart of a subroutine corresponding to step S500 of the main routine.

FIG. 11 is a flowchart corresponding to the subroutine of step S509 of FIG.

FIG. 12 is a flowchart corresponding to the subroutine of step S515 of FIG.

FIG. 13 is a graph accompanying the flowchart of FIG.

FIG. 14 is a flowchart corresponding to the subroutine of step S517 of FIG.

FIG. 15 is a flowchart corresponding to the subroutine of step S519 of FIG.

16 is a flowchart corresponding to the subroutine of step S518 of FIG.

FIG. 17 is a graph accompanying the flowcharts of FIGS. 14 and 15;

FIG. 18 is a flowchart corresponding to the subroutine of step S600 of the main routine.

FIG. 19 is a flowchart corresponding to the subroutine of step S600 of the main routine.

FIG. 20 is a flowchart corresponding to the subroutine of step S600 of the main routine.

FIG. 21 is a graph associated with the flowcharts of FIGS.

FIG. 22 is a time chart when a shift change is performed during braking.

FIG. 23 is a flowchart of a subroutine corresponding to step S700 of the main routine.

FIG. 24 is a flowchart corresponding to the subroutine of step S900 of the main routine.

FIG. 25 is a flowchart corresponding to the subroutine of step S902 in FIG.

FIG. 26 is a flowchart corresponding to the subroutine of step S903 of FIG.

FIG. 27 is a graph accompanying the flowchart of FIG. 25.

FIG. 28 is a graph accompanying the flowchart of FIG. 26.

FIG. 29 is a flowchart of another embodiment corresponding to FIGS. 9 and 10.

FIG. 30 is a flowchart corresponding to the subroutine of step S582 of FIG. 29.

FIG. 31 is a flowchart of another embodiment corresponding to FIG. 25.

[Explanation of symbols]

6 Motor / mission control ECU (braking control means) 7 Brake ECU (abnormality determination means, braking control means) 8 Brake pedal (brake operator) 20 ₂ Battery current sensor (sensor)

Front Page Continuation (72) Inventor Atsuo Ohno 1-4-1 Chuo, Wako City, Saitama Prefecture Honda R & D Co., Ltd.

Claims (4)

[Claims] 1. A braking device for an electric vehicle capable of selecting either one or both of hydraulic braking and regenerative braking based on the operation of a brake operator (8) and the running state of the vehicle, which may be generated by regenerative braking. Based on the output of the abnormality determining means (7), which compares the estimated power with the actual power actually generated by the regenerative braking and makes an abnormality determination when the difference exceeds a predetermined value. Braking control means (6, 7) for selecting hydraulic braking by means of
Braking device for electric vehicles. 2. A battery generated by regenerative braking in a braking device for an electric vehicle capable of selecting either one or both of hydraulic braking and regenerative braking based on the operation of a brake operator (8) and the traveling state of the vehicle. A sensor (20 ₂ ) for detecting a charging current, and an abnormality determining means (7) for making an abnormality determination when the torque that can be generated by regenerative braking is equal to or greater than a predetermined value and the battery charging current is negative. Braking control means (6, 7) for selecting hydraulic braking based on the output of the abnormality determination means (7),
Braking device for electric vehicles. 3. A battery generated by regenerative braking in a braking device for an electric vehicle capable of selecting either one or both of hydraulic braking and regenerative braking based on the operation of a brake operator (8) and the running state of the vehicle. A sensor (20 ₂ ) for detecting a charging current, an abnormality determining means (7) for making an abnormality determination when the battery charging current is positive when there is no torque generated by regenerative braking, and the abnormality determining means (7). Braking control means for selecting hydraulic braking based on the output (6,
7) and a braking device for an electric vehicle. 4. The abnormality determination means (7) makes an abnormality determination when an abnormal state is detected a plurality of times consecutively at a predetermined time interval, according to any one of claims 1 to 3. A braking device for the electric vehicle described.