JP2808162B2 - Vehicle slip control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle slip control device, and more particularly, to a vehicle slip control that can detect a failure of a wheel speed sensor at a desired time. The present invention relates to a control device.

(Prior Art) In a control device for a vehicle, when an excessive slip occurs between a drive wheel and its ground contact surface at the time of starting or running of the vehicle, the drive is controlled by restricting the slip within a desired range. Secure the driving force transmitted from the wheels to the road surface,
2. Description of the Related Art A slip control device provided with traction control means configured to improve the starting performance or acceleration performance of a vehicle is known (for example, Japanese Patent Application Laid-Open No. 58-16948,
JP-A-57-22948, JP-A-62-231836, JP-A-62-170740, etc.).

The traction control device reduces the output of the engine such that the slip ratio of the drive wheel detected based on the wheel speed of each wheel converges to at least a predetermined target slip ratio or less, and / or To suppress the drive torque transmitted to the drive wheels by increasing the brake fluid pressure, thereby restricting the slip of the drive wheels and ensuring a desired coefficient of friction between the drive wheels and the road surface. Was composed.

Also, in the slip control device, together with the traction control means, detects the skid state of each wheel,
By adjusting the brake fluid pressure, when braking the vehicle,
2. Description of the Related Art There is known an anti-lock brake system (hereinafter, referred to as ABS) which works to maintain a desired frictional force between each wheel and a road surface to secure an optimal braking force of a vehicle.

The ABS detects the skid state of each wheel based on the estimated vehicle body speed calculated based on the vehicle body deceleration and the wheel speed of each wheel, and locks the wheels during braking according to the skid state. In order to counteract the tendency, the brake fluid pressure is reduced to thereby ensure a desired coefficient of friction between each drive wheel and the road surface during braking.

Such a slip control device generally includes a sensor rotor that rotates integrally with each wheel to detect the wheel speed of each wheel, and an electromagnetic pickup type sensor that detects the rotation state of the sensor rotor. In addition to having wheel speed sensors, to detect the failure of each wheel speed sensor, when the sensor rotor rotates, the detection result of each wheel speed sensor is compared to detect a failure such as breakage or missing of the outer peripheral gear of the sensor rotor. Failure detecting means for determining

(Problems to be Solved by the Invention) Here, in order for the driver to recognize the braking performance of the vehicle early by detecting the cause of the malfunction of the ABS at an early stage, the failure of the wheel speed sensor by the failure detection means is required. The determination is desirably performed at an early stage of driving, for example, immediately after the vehicle starts moving.

However, in the above-mentioned slip control device, when the irregular wheel speed change occurs due to the slip of the drive wheel immediately after the start, the malfunction detection means erroneously recognizes the wheel speed change as a wheel speed sensor malfunction. In order to avoid such a situation, after the vehicle speed reaches a relatively high speed range, a failure determination is started.

The present invention has been made in view of such a point, and a purpose thereof is to provide a wheel speed sensor for detecting a wheel speed of each wheel, and a method of detecting a driving wheel based on a detection result of the wheel speed sensor. Traction control means for suppressing and controlling the driving torque transmitted to the driving wheels so that the slip converges at least to a predetermined target slip ratio or less, and cancels the locking tendency of the wheels based on the detection result of the wheel speed sensor. Vehicle anti-lock brake system that regulates brake fluid pressure as described above, provides a vehicle slip control device capable of detecting an abnormality of a wheel speed sensor early and reliably after transmitting a vehicle. It is in.

(Means and Actions for Solving the Problems) In order to achieve the above object, the present invention provides a vehicle slip control device, comprising: a vehicle speed detecting means for detecting a vehicle speed; When the above vehicle speed is detected and the traction control unit is not performing drive torque suppression control, a failure determination of each wheel speed sensor is performed based on a detection result of each wheel speed sensor,
And a failure detecting means for enabling the operation of the anti-lock brake system only when a failure of the wheel speed sensor is not detected by the failure determination.

In the slip control device having the above configuration, when an excessive slip occurs on the drive wheels immediately after the start of the vehicle, the traction control unit controls the drive torque to be suppressed. When the torque suppression control is being performed, even if a vehicle speed equal to or higher than a predetermined vehicle speed is detected, a failure determination of the wheel speed sensor is not performed. Is not erroneously recognized as a failure of the wheel speed sensor. Therefore, the predetermined vehicle speed can be set to a considerably low speed, for example, about 3 km / h, so that the failure detection means can quickly and reliably determine the failure at the time of starting on a normal traveling road.

In addition, when the traction control unit performs drive torque suppression control by, for example, starting the vehicle on a traveling road surface having a relatively low friction coefficient, the failure detection unit performs predetermined control after the drive torque suppression control ends. When a vehicle speed equal to or higher than the vehicle speed is detected, the failure determination of the wheel speed sensor is promptly performed. Therefore, the failure determination of the wheel speed sensor is performed at the earliest possible time after the vehicle starts, that is, when the traction control is performed. This is performed immediately after the drive torque suppression control by the means is completed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic overall configuration diagram of a vehicle provided with a vehicle slip 1 control device according to an embodiment of the present invention. Figure 2A
FIG. 2 is a schematic perspective view of a wheel speed sensor for the left rear wheel shown in FIG. 1, and FIG. 2B is a schematic partial front view of the wheel speed sensor shown in FIG. 2A.

In FIG. 1, a vehicle A has front wheels 1FL and 1FR as left and right driven wheels, and has rear wheels 1RL and 1RR connected to a drive system of the vehicle A as left and right driving wheels.

The drive system of the vehicle A includes an engine 2 mounted on the front of the vehicle body, an automatic transmission 3 connected to a crankshaft of the engine 2, a propeller shaft 4 connected to an output shaft of the automatic transmission 3, and a propeller shaft 4. It is substantially composed of a differential gear 5 connected to the rear end, and drive wheels 6L and 6R extending left and right from the differential gear 5 and connected to left and right rear wheels 1RL and 1RR, respectively.

A throttle valve 42 for controlling the amount of intake air is provided in an intake passage 41 of the engine 2.
42 is a throttle wire 112t, throttle opening adjustment mechanism
Accelerator pedal 43 via 44 and accelerator wire 112a
It is connected to. The throttle opening adjustment mechanism 44 includes a motor 106, and when the motor 106 is not operating,
The amount of accelerator depression of the accelerator pedal 43 is determined by the throttle valve.
42, the throttle opening is made to correspond 1: 1 to the accelerator opening, and in the operating state of the motor 106, the forward rotation, the reverse rotation, or the rotation of the motor 106 causes the accelerator pedal 43 to operate. The depression amount is reduced and transmitted to the throttle valve 42, whereby the ratio of the throttle opening to the accelerator opening is adjusted in the range of 1: 1 to 0: 1. For example, when the motor 106 is not operating, the throttle opening adjustment mechanism 44 operates the accelerator pedal 43
However, when the accelerator is operated to the accelerator opening A%, for example, the accelerator opening is directly transmitted to the throttle valve 42, and the throttle valve 42 is operated to the throttle opening A%. Further, the throttle opening adjustment mechanism 44 changes the throttle opening in the range of A% to 0% when the accelerator opening is A% by rotating the motor 106 forward or backward, and holds the rotation of the motor 106. Thus, the set throttle opening can be maintained.

The automatic transmission 3 is a hydraulically operated lock-up clutch.
It comprises a torque converter 11 having 11A and a transmission 12 provided with a multi-speed gear mechanism.
The lock-up clutch 11A of the torque converter 11 is connected to a solenoid 13 constituting a hydraulic control circuit of the automatic transmission 3.
The multi-speed gear mechanism of the transmission 12 is engaged or released by the selective excitation or demagnetization of b, and a plurality of solenoids constituting the hydraulic control circuit.
The shift operation is performed by the selective excitation or demagnetization of 13a.

The vehicle A also has brakes 21FL, 21RR, 21RL, 21RR disposed on the wheels 1FL, 1FR, 1RL, 1RR, respectively, front-wheel-side brakes 21FL, 21FR calipers 22FL, 22FR, and brake piping 23F.
Tandem type master cylinder 27 connected via L, 23FR, rear wheel side brakes 21RL, caliper 22RL, 22 for 21RR
A hydraulic booster type booster 26 connected to the RR via brake pipes 22RL, 23RR, 33 and a brake device substantially constituted by a brake pedal 25 connected to the booster 26 are provided.

The master cylinder 27 applies the desired brake fluid pressure to the front wheel 1F.
L, 1FR, and converts the depressing force of the brake pedal 25 increased by the booster 26 into brake fluid pressure, and converts the brake fluid pressure into the first and second brake pressures of the master cylinder 27. Are supplied to brake cylinders provided in the calibers 22FL, 22FR via brake pipes 23FL, 23FR connected to the discharge ports 27a, 27b, respectively.

The brake pipes 23FL and 23FR are connected to relief pipes 38FL and 38FR, respectively, which can communicate with the reservoir tank 31, and the relief pipes 38FL and 38FR respectively function as outlet valves of an anti-lock brake system (ABS). Closed solenoid proportional proportional on-off valve 37FL, 37
FR is inserted. FIG. 1 shows a state in which the on-off valves 37FL and 37FR are located at the fully closed position.

The booster 26 boosts the depressing force of the brake pedal 25 and transmits the boosted pressure to the master cylinder 27. The booster 26 uses the hydraulic pressure in the booster chamber (not shown) as a brake hydraulic pressure to form a brake pipe 33, It is configured to supply the brake cylinders provided on the calipers 22RL and 22RR via 23RL and 23RR. The booster chamber of the booster 26 is connected to a hydraulic pump 29 via a hydraulic supply pipe 28 to which an accumulator (not shown) is connected and connected.
The hydraulic pump 29 supplies the hydraulic fluid in the reservoir tank at a predetermined pressure, and holds the hydraulic fluid at a predetermined line pressure by a pressure accumulating operation of the accumulator. Further, a return pipe 30 for returning the hydraulic fluid discharged from the booster 26 to the reservoir tank 31 is connected to the booster 26.

Further, the boosting chamber of the booster 26 is connected to a brake pipe 33, and a normally open electromagnetic on-off valve 34 is inserted into the brake pipe 33, and a one-way valve 35 is connected to the on-off valve 34. They are connected in parallel. FIG. 1 shows the on-off valve 34.
Is shown in the fully open position.

The brake pipe 33 is connected to the right and left rear wheels 1R at the junction a.
It branches into brake pipes 23RL and 23RR for L and 1RR, and normally open electromagnetic proportional type on-off valves 36L and 36R are interposed in the brake pipes 23RL and 23RR, respectively. The brake pipes 23RL and 23RR are provided with relief pipes 38RL that can communicate with the reservoir tank 31 on the downstream side of the on-off valves 36L and 36R.
The 38RR branches off, and the normally closed electromagnetic proportional on-off valves 37RL and 37RR serving as outlet valves of the antilock brake system (ABS) are interposed in the relief lines 38RL and 38RR, respectively. In FIG.
The state where the on-off valves 37RL and 37RR are located at the fully closed position is shown.

A branch pipe 28a that can communicate with the pipe 28
And a normally closed electromagnetic on-off valve 32 is inserted in the branch pipe 28a. FIG. 1 shows a state where the on-off valve 32 is located at the fully closed position.

The vehicle A is provided with wheel speed sensors 63, 64, 65, and 66 for detecting wheel speeds of the wheels 1FL, 1FR, 1RL, and 1RR. Pulse gear type sensor rotors 63a, 64a that rotate integrally with 1RR
65a, 66a and electromagnetic pickup type sensors (hereinafter simply referred to as electromagnetic pickups) 63b, 6 fixed to the vehicle body side
4b, 65b, and 66b.

2A and 2B, a wheel speed sensor 65 provided on the left rear wheel 1RL is provided with a generally disc-shaped sensor rotor 65a having outer teeth formed at predetermined intervals. Wheel 1
It is fixed to a rear hub (not shown) that rotates integrally with the RL, and detects the rotation of the sensor rotor 65a based on the proximity and separation of the outer peripheral teeth as an AC voltage having a period proportional to the rotation speed. Output electromagnetic pickup 65b
Are fixed to a hub spindle (not shown).

As shown in FIG. 1, the vehicle A also includes a throttle sensor 61 for detecting the opening of the throttle valve 42, a vehicle speed sensor 62 for detecting the vehicle speed based on the rotation speed of the propeller shaft 4, and an amount of depression of an accelerator pedal 43. An accelerator opening sensor 67 for detecting, a motor rotation amount detection sensor 68 for detecting a rotation amount of the motor 106, a steering angle sensor 69 for detecting a steering amount of a steering wheel (not shown), are manually operated. Slip control mode selection switch 70, brake pedal
There is provided a brake switch 71 for detecting the depression of the brake pedal 25 and a G sensor 73 for detecting the deceleration of the vehicle A during braking.

The vehicle A includes an automatic transmission control unit UAT for controlling lock-up and a shift speed of the automatic transmission 3 by controlling solenoids 13a and 13b of a hydraulic control mechanism of the automatic transmission 3, and a vehicle. When braking A, each wheel 1FL,
Anti-lock brake system control means (hereinafter referred to as ABS control means) that works to maintain a desired frictional force between the 1FR, 1RL, 1RR and the road surface and to secure an optimal braking force of the vehicle A; When running or starting vehicle A, rear wheels 1RL, 1
A slip control unit UTR including traction control means for suppressing a slip of the rear wheels 1RL and 1RR when an excessive slip occurs in the RR and securing a desired driving force of the rear wheels 1RL and 1RR. Is provided.

Detection signals from the throttle sensor 61 and the vehicle speed sensor 62 are input to the automatic transmission control unit UAT. The automatic transmission control unit UAT performs a lockup determination and a shift determination based on the shift characteristics and the lockup characteristics in a predetermined conversion map stored in advance, based on the detection results of these sensors, and determines whether the automatic transmission 3 A control signal is output to the solenoids 13a and 13b to perform lockup control and shift control of the automatic transmission 3.

The slip control unit UTR includes the throttle sensor 61, the vehicle sensor 62, and the wheel speed sensors 63, 64, 65, 6
6, accelerator opening sensor 67, motor rotation amount detection sensor 6
8, steering angle sensor 69, slip control mode selection switch 7
0, the detection results of the brake switch 71 and the G sensor 73 are input respectively.

The slip control unit UTR has an input interface for receiving each signal from each of the above sensors, a ROM in which a predetermined control program and various maps are stored, a RAM provided with various memories necessary for executing control, and C
A microcomputer comprising a PU, an output interface for outputting a control signal to the automatic transmission control unit UAT, and each on-off valve 32, 34, 36L, 36R, 37FL,
A control circuit is provided for controlling the opening and closing of the 37FR, 37RL, and 37RR and for controlling the operation of the motor 106 of the throttle opening adjustment mechanism 44.

In the slip control unit UTR thus configured, the ABS control means includes an estimated vehicle speed calculated based on the vehicle deceleration detected by the G sensor 73;
Each wheel 1FL-1 detected by each wheel speed sensor 63-66
The skid state of each of the wheels 1FL to 1RR is detected from the difference between the RR and the wheel speed, and when it is determined that any of the wheels 1FL to 1RR has a tendency to lock, the on-off valve 37FL is used to cancel the tendency to lock the wheels. , 37FR, 37RL, 37RR by controlling the opening degree,
Brake pipe 23FL on the wheels that tend to lock,
It is configured to reduce the line pressure of 23FR, 23RL, and 23RR. The ABS control means is configured to execute the above control only when an ABS control permission signal is input from a failure detection means described later, and after the vehicle A starts, the ABS control permission signal is output. Until the input, the above control is not performed.

Further, in the slip control unit UTR, the traction control means controls the rear wheels 1R when the vehicle A starts or runs.
L, 1RR, that is, engine control for transiently reducing the output of the engine 2 by controlling the amount of rotation of the motor 106 of the throttle opening adjustment mechanism 44 when excessive slip occurs in the drive wheels, and braking. By controlling the opening and closing of the on-off valves 32, 34 incorporated in the hydraulic circuit of the device, and by controlling the on-off of the on-off valves 36L, 36R37RL, 37RR,
Brake control for adjusting the brake fluid pressure is performed, whereby the drive torque transmitted to the rear wheels 1RL, 1RR is reduced, and the slip of the rear wheels 1RL, 1RR is controlled.

In the engine control described above, by operating the motor 106 of the throttle opening adjustment mechanism 44, the opening of the throttle valve 42 with respect to the accelerator opening of the accelerator pedal 43 is reduced, thereby reducing the engine output of the engine 2. It is performed by

In addition, the above-described brake control moves the on-off valve 34 to the fully closed position,
Further, by switching the open / close valves 32 to the fully open position, the line pressure of the hydraulic pressure supply pipe 28 causes the brake pipe 23R
This is performed by raising the line pressure of L and 23RR and holding this line pressure by closing the on-off valves 36R and 36L, or releasing it by opening the on-off valves 37RL and 37RR.

FIG. 3 is a diagram showing, as a time chart, general wheel speed characteristics of drive wheels during traction control and the relationship between engine control and brake control by the traction control means. FIG. 4 is an explanatory diagram showing, in a block diagram, a circuit for determining a target slip value for brake control and a target slip value for engine control in order to set a target slip ratio of a drive wheel. FIG. 5 is a diagram showing characteristics of a throttle opening lower limit control value for engine control set by the traction control means.

FIG. 3 shows one driving wheel of the vehicle A, for example, the left rear wheel 1R.
3 shows general wheel speed characteristics at the time of traction control in L, and the wheel speed characteristics at the time of traction control of the other drive wheel, for example, the right rear wheel 1RR, are also substantially the same as those shown in FIG. It has the same characteristics. Therefore, the following description regarding FIG. 3 is made assuming that the wheel speed characteristics of the left rear wheel 1RL are shown in FIG.

FIG. 3 shows the wheel speed of the left rear wheel 1RL during traction control detected by the wheel speed sensors 65 and 66, that is, the drive wheel speed VK _RL, and the left and right front wheels detected by the wheel speed sensors 63 and 64. The average value of the 1FL and 1FR wheel speeds is the driven wheel speed VJ
And a threshold value a corresponding to an engine control target slip ratio SE for regulating the slip ratio of the rear wheel 1RL by controlling the throttle opening, and a brake fluid. By controlling the pressure, the rear wheel 1RL
A threshold value b corresponding to a target slip ratio SB for brake control for regulating the slip ratio of the vehicle is shown. Note that the threshold value b is set to a value larger than the threshold value a.

Here, the slip ratio S _RL of the rear wheels 1RL is calculated by the following equation.

The target slip ratios SE and SB are calculated by the following equations.

Note that SET and SBT are a target slip value for engine control and a target slip value for brake control, which are commonly set for the rear wheels 1RL and 1RR, respectively.

The engine control target slip value SET and the brake control target slip value SBT are set such that the rear wheel 1RL secures a desired driving force when the vehicle A goes straight, and is shown in FIG. As described above, it is determined by the road surface maximum friction coefficient μmax, the vehicle speed, the accelerator opening, the steering wheel angle, and the traveling mode selected by the slip control mode selection switch 70.

In FIG. 4, a control unit UTR includes a basic value STBO of a brake control target slip value SBT and a basic value STAO of an engine control target slip value SET for each rear wheel 1RL, 1R.
A maximum friction coefficient μmax of the road surface estimated from the larger one of the slip ratios S _RL and S _RR of R and the driven wheel speed VJ is stored as a parameter in the map 81.
In 81, the basic value STBO is set to a value larger than the basic value STAO. The above target slip values SET and SBT are
It is obtained by multiplying each of the basic values STA and STBO by a correction gain coefficient KD. The correction gain coefficient KD is obtained by multiplying various gains stored in the map or the tables 82, 83, 84, 85, that is, the gain coefficients VG, ACPG, STRG, and MODEG. VG is for ensuring the stability of the vehicle A according to the increase in the vehicle speed. The VG is set by the map 82 based on the vehicle speed, and the gain coefficient ACPG secures the driving force according to the driver's acceleration request. The gain coefficient STRG is set by the map 83 based on the accelerator opening, and is for ensuring the general stability of the vehicle A at the time of turning, and based on the steering angle of the steering wheel. The gain coefficient MODEG is set by the map 84, and the gain coefficient MODEG is set based on the selection of the sport mode emphasizing driving performance and the normal mode emphasizing stability by the table 85 manually selected by the driver. There is set.

In FIG. 3, the time point t ₁ earlier, a large slip on the rear wheel 1RL has not occurred, the throttle opening degree, by holding the mode 106 of the throttle opening adjustment mechanism 44 inoperative, the accelerator The basic throttle opening TH · B obtained in proportion to the opening is set, and the brake fluid pressure supplied to each of the brakes 21FL to 21RR is controlled by each of the on-off valves 32, 34, 36R, 36L, 37FL to The voltage is lowered by holding 37RR in the normal position.

Driving wheel speed VK _RL of the rear wheels 1RL, at time point t _1, has increased to the threshold a target slip ratio SE for engine control, the engine control by the traction control means is started at the time point t _1, Slip control unit UTR
The traction control means includes a throttle opening adjustment mechanism 44.
By operating the motor 106, feedforward control is performed to reduce the throttle opening to the lower limit control value SM at once.

As shown in FIG. 5, the throttle opening lower limit control value SM is stored as a map 91 using the vehicle speed and the road surface maximum friction coefficient μmax as parameters, and is determined based on the vehicle speed and the road surface maximum friction coefficient μmax. Is done. In FIG. 5, when μmax = 1, the friction coefficient is set to the smallest, and μmax = 5, the friction coefficient is set to the largest.
On road surfaces where max is relatively small, the lower limit control value SM
Is set to a relatively large value to promote an early output decrease of the engine 2, and on a road surface having a relatively large maximum friction coefficient μmax, the lower limit control value SM is set to a relatively small value.
The stall of the vehicle A due to an excessive decrease in the output of the engine 2 is avoided.

Traction control means, after once lower control value SM the throttle opening, so that the slip ratio S _RL of the rear wheels 1RL becomes the target slip ratio SE control engine throttle valve 42
Is feedback controlled. This feedback control, the slip ratio S _RL of the rear wheels 1RL is the target slip ratio
It is performed by controlling the motor 106 of the throttle opening adjustment mechanism 44 to rotate forward or reverse so as to converge to SE to reduce the throttle opening, and the throttle opening is an opening regulated by the motor 106, that is, , Opening degree TH · M in FIG.
Becomes

In FIG. 3, the driving wheel speed VK _RL of the rear wheels 1RL, despite the engine control is performed, in t ₁ after the time has further increased with respect to the driven wheel speed VJ, t ₂ time The drive wheel speed VK _RL of the rear wheel 1RL is equal to the target slip ratio S
It has increased to the threshold value b of B. The traction control means of the slip control unit UTR starts the traction control by the brake control when the drive wheel speed VK _RL reaches the threshold value b, and the slip ratio S _RL of the rear wheel 1RL is changed to the target slip ratio SB for the brake control. Converge on the brake piping
On-off valves 32, 34, 36R located at 28a, 33, 23RL, 38RL
Control signals are output to L and 37RR respectively to brake the rear wheel 1RL.
The brake fluid pressure 21RL while boosting the pressure Pn _RL, holds the brake fluid pressure Pn _RL.

With this engine control and brake control, the rear wheel 1RL
The slip is suppressed, t ₃ time, the threshold c, the driving wheel speed VK _RL is corresponding to the target slip ratio SB for controlling brake
Is below, the slip control unit UTR
By lowering the brake fluid pressure by opening the, but ends the brake control, engine control, the slip ratio S _RL
Is continued until the possibility that the increase in the pressure disappears, that is, until the accelerator opening is fully closed.

The wheel speed characteristics of the left rear wheel 1RL during the traction control have been described above with reference to FIG. 3, but the target slip ratios SE and SB for the right rear wheel are also the same as for the left rear wheel 1RL.
Traction control by engine control and brake control is performed on the basis of the characteristic of the drive wheel speed VK _RR of the right rear wheel 1RR during traction control is generally the left rear wheel 1RL
Similarly, FIG. 3 shows the wheel speed characteristics shown in FIG.

When the slip of one of the rear wheels 1RL or 1RR increases early, the engine control is performed by the left and right rear wheels 1R.
Since control is performed in common for L and 1RR, wheel 1R
It is started when either the slip ratio S _RL or S _RR of L or 1RR or the average value of the slips S _RL and S _RR reaches the target slip ratio SE. Further, the brake control is generally configured to perform so-called left and right independent control, and the rear wheels 1RL, 1RL
When the slip ratios S _RL and S _RR of the _RR reach the target slip ratio SB, respectively, the rear wheels 1RL or 1RR or the rear wheels 1RL or SRR converge below the target slip ratio so that the respective slip ratios S _{RL and} S _RR converge below the target slip ratio. Wheel 1R
The brake fluid pressure for L or 1RR is respectively increased.

The slip control unit UTR thus configured is further provided with a slip control unit as a fail-safe mechanism.
Failures such as abnormalities of various storage means built in the UTR, failures of ROM and RAM, etc. are determined, and the system down of the ABS control means and the traction control means and the driver is notified of the failure of the wheel speed sensors 63 to 66. It is provided with a failure detection means for warning.

FIG. 6 is a schematic block diagram partially showing the function of the slip control unit UTR, and FIG. 7 is a flowchart showing a method of detecting a failure of the wheel speed sensor in the failure detecting means shown in FIG. In FIG. 6, the symbol P means a step.

In FIG. 6, the vehicle speed sensor 62
And electromagnetic pickup for each wheel speed sensor 63, 64, 65, 66
The detection signals 63b to 66b are input. Further, the failure detection means includes traction control by traction control means,
That is, it is detected whether the engine control or the brake control is being performed. The failure detecting means compares the detection signals of the electromagnetic pickups 63b to 66b based on these detection results when the sensor rotors 63a to 66a of the wheel speed sensors 63 to 66 rotate, and detects the outer circumference of the sensor rotors 63a to 66a. Judgment of failures such as gear breakage or missing, and when such failures are detected, the ABS control means and traction control means are shut down and the failure lamp and failure buzzer provided in the driver's seat are turned on or activated. Output a signal.

As shown in FIG. 7, the failure detecting means includes a vehicle speed sensor 62.
And the wheel speed sensors 63, 64,
Wheel speeds V _FL , V _FR , V _RL , V _RR detected by 65, 66
Is read (P1). When the vehicle speed V is equal to or higher than a predetermined vehicle speed V ₀ , for example, 3 km / h, and the traction control is not performed by the traction control unit (P3, 4), the failure detection unit further detects the wheel speed V _FL , V _FR , V
_RL , V _RR are compared, and each wheel speed V _FL , V _FR , V _RL , V _RR is
When an error is within a predetermined error range α, for example, an error range corresponding to a wheel speed of 5 km / h, an ABS control permission signal for enabling the operation of the ABS control means is output to the ABS control means (P5, 6).

Further, when any one of the wheel speeds V _FL , V _FR , V _RL , V _RR exceeds the predetermined error range α, the failure detection means shuts down the traction control means and the ABS control means, A failure signal is output so that the driver's seat recognizes that the traction control unit and the ABS control unit are down, while preventing malfunction of the traction control unit and the ABS control unit, and a failure lamp and / or a failure buzzer (FIG. (Not shown) is turned on or activated (P7, 8).

On the other hand, in order to not mistakenly change the irregular wheel speeds V _FL , V _FR , V _RL , V _RR which may be caused by the slip of the rear wheels 1RL, 1RR immediately after the start as a failure of the wheel speed sensors 63 to 66,
When the vehicle speed V does not reach the predetermined vehicle speed V ₀ , the failure detecting means does not compare the wheel speeds V _FL , V _FR , V _RL , V _RR and therefore does not make a failure determination (P2).

In addition, the traction control means controls the rear wheels 1RL and 1RR.
In order to suppress the slip immediately after starting,
When the traction control is being performed by the traction control means and the vehicle speed V has not reached the predetermined vehicle speed V ₀ , the failure detection means does not compare the wheel speeds V _FL , V _FR , V _RL and V _RR. Therefore, failure determination is not performed (P3).

Further, the control flow shown in FIG. 6 is executed at predetermined time intervals, and when the traction control means ends the traction control, if the vehicle speed V is equal to or higher than the predetermined vehicle speed V ₀ , wheel speeds _{V FL, V FR, V RL} , V RR are compared, since each wheel speed whether within a predetermined error range α is determined (P5,6), the wheel speed sensors 63 to 66 The failure is quickly determined after the traction control ends.

As described above, in the above embodiment, the slip control unit UTR detects a vehicle speed equal to or higher than the predetermined vehicle speed V ₀ and, when the traction control unit is not performing traction control, based on the detection result of each wheel speed sensor. The failure determination of the wheel speed sensors 63 to 66 is performed, and when no failure of the wheel speed sensors 63 to 66 is detected by the failure determination,
Failure detection means configured to enable operation of the antilock brake system is provided.

Therefore, when the traction control means is performing traction control, even as the predetermined vehicle speed greater than or equal _to V ₀ of the vehicle speed is detected, since the failure determination of the wheel speed sensor is not performed, the rear wheels 1RL immediately start, 1RR The wheel speed sensors 63 to 66 are not erroneously recognized as irregular wheel speed changes that may be caused by the slip of the vehicle.
V ₀ is set to a considerably low speed.

Further, when traction control is performed by the traction control means, for example, when the vehicle starts on a traveling road surface having a relatively low coefficient of friction, the failure detection means sets a predetermined vehicle speed or more after the end of the drive torque suppression control. When the vehicle speed is detected, the failure determination of the wheel speed sensors 63 to 66 is quickly performed, so that the failure determination of the wheel speed sensors 63 to 66 can be performed at the earliest time after the vehicle starts, that is, when the appropriate failure determination can be performed, that is, This is performed immediately after the traction control by the traction control means ends.

As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and needless to say, various changes can be made within the scope of the invention described in the claims. Absent.

For example, the failure detecting means includes the wheel speeds _VFL , _VFR , VFR
The failure determination of the wheel speed sensor is performed by determining whether _RL and V _RR are within a predetermined error _range.In addition to the failure determination, all wheel speed detection signals from the wheel speed sensor are output. It may be configured such that it is determined whether or not a wheel speed sensor has been output, and a failure of the wheel speed sensor is also determined when it is recognized that a wheel speed detection signal is not output for only one wheel.

Further, in the above embodiment, the engine control is performed by controlling the throttle opening to reduce the output of the engine. However, the present invention provides a variable control of the ignition timing of the engine and / or the control of the engine. The present invention can also be applied to a slip control device that performs engine control so as to reduce engine output by fuel cut, or a slip control device that uses these engine control methods and an engine control method that controls throttle opening. is there.

Further, the control of the throttle opening may be performed by a step motor that opens and closes the throttle valve instead of the above-described throttle opening adjusting mechanism.

(Effect of the Invention) According to the above configuration of the present invention, a wheel speed sensor for detecting the wheel speed of each wheel, and the slip of the drive wheel is set to at least a predetermined target based on the detection result of the wheel speed sensor. Traction control means for suppressing and controlling the driving torque transmitted to the driving wheels so as to converge to the slip ratio or less;
An anti-lock brake system that adjusts brake fluid pressure so as to cancel the tendency to lock the wheels based on the detection result of the wheel speed sensor. It is possible to provide a vehicle slip control device that can detect a sensor abnormality.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a vehicle provided with a vehicle slip control device according to an embodiment of the present invention. FIG. 2A is a schematic perspective view of the wheel speed sensor for the left rear wheel shown in FIG. 1, and FIG. 2B is a schematic partial front view of the wheel speed sensor shown in FIG. 2A. FIG. 3 is a diagram showing, as a time chart, general wheel speed characteristics of drive wheels during traction control and the relationship between engine control and brake control by the traction control means. FIG. 4 shows how to set the target slip ratio of the drive wheels.
FIG. 4 is an explanatory diagram showing a block diagram of a circuit for determining a brake control target slip value and an engine control target slip value. FIG. 5 is a diagram showing characteristics of a throttle opening lower limit control value for engine control set by the traction control means. FIG. 6 is a schematic block diagram partially showing the function of the slip control unit UTR. FIG. 7 is a flowchart showing a method of detecting a failure of the wheel speed sensor in the failure detecting means shown in FIG. 1FL, 1FR, 1RL, 1RR… Left front wheel, right front wheel, left rear wheel, right rear wheel, 2… engine, 3… automatic transmission, 4… propeller shaft, 5… differential gear, 6L, 6R …… Drive shaft, 21FL, 21FR, 21RL, 21RR …… Brake, 22FL, 22FR, 22RL, 22RR …… Caliper, 23FL, 23FR, 23RL, 23RR, 33 …… Brake piping, 25 …… Brake pedal, 26 …… Booster, 27 ... Master cylinder, 28 ... Hydraulic supply pipe, 28a ... Branch pipe, 29 ... Return pipe, 31 ... Reservoir tank, 32, 34, 36L, 36R, 37FL, 37FR, 37RL, 37RR ... On-off valve, 38FL, 38FR, 38RL, 38RR ... Relief pipeline, 41 ... Intake passage, 42 ... Throttle valve, 43 ... Accelerator pedal, 44 ... Throttle opening adjustment mechanism, 61 ... Throttle Sensor 62, Vehicle speed sensor 63, 64, 65, 66 Wheel speed sensor 63a, 64a, 65a, 66a Sensor rotor 63b 64b, 65b, 66b: electromagnetic pickup sensor, 67: accelerator opening detection sensor, 68: motor rotation amount detection sensor, 69: steering angle sensor, 70: slip control mode selection switch, 71: brake Switch 73 G sensor 106 Motor 112 a Accel wire 112 t Throttle wire UTR Slip control unit UAT Automatic transmission control unit a Confluence SE Target slip ratio for engine control, SB ... Target slip ratio for brake control.

Continued on the front page (72) Inventor Kazutoshi Nobumoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Fumio Kageyama 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-64-90860 (JP, A) JP-A-60-128056 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60T 8/58

Claims (1)

(57) [Claims] A wheel speed sensor for detecting a wheel speed of each wheel, and based on a detection result of the wheel speed sensor, a slip of a driving wheel converges to at least a predetermined target slip ratio or less. A vehicle having traction control means for suppressing and controlling drive torque transmitted to drive wheels, and an anti-lock brake system for adjusting brake fluid pressure based on a detection result of the wheel speed sensor to cancel a tendency to lock wheels. A vehicle speed detecting means for detecting a vehicle speed, a vehicle speed higher than a predetermined vehicle speed is detected by the vehicle speed detecting means, and when the traction control means is not performing drive traction suppression control, Failure determination of the wheel speed sensor is performed based on the detection result of the wheel speed sensor, and the failure determination determines that the wheel speed sensor has failed. Only when not detected, and a fault detecting means for enabling operation of the antilock braking system, a slip control device for a vehicle, characterized in that.