JPH01295167A - Abnormality detecting device for wheel speed - Google Patents

Abstract

PURPOSE:To detect abnormality by regarding a speed obtained by a vehicle speed sensor as a reference speed and comparing it with detected speeds from respective wheel speed sensors. CONSTITUTION:When a brake sensor 6 detects braking operation not being performed, a controller 5 computes the traveling speed of a vehicle from an engine rotating speed from a rotating speed sensor 7 and a gear shift position from a shift position sensor 8. Then when the detected vehicle speed becomes constant, it is regarded as the reference speed. Here, when the detected speed obtained by a wheel speed sensor 4 deviates from the reference speed exceeding a permissible range greatly, the controller 5 outputs an abnormality signal to turn on an alarm lamp 10 and then inhibit an antiskid device from operating.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a wheel speed abnormality detection device, and more specifically, it is used in an anti-skid device by detecting that the wheel speed is in an abnormal state. This system is designed to detect abnormalities in the wheel speed sensors, abnormal tire air pressure, and the installation of emergency tires.

"Prior Art" Conventionally, an anti-skid device is equipped with a plurality of wheel speed sensors that detect the speed of each wheel, and when the brake is applied, the highest wheel speed detected by each wheel speed sensor is used. Calculate the vehicle speed from
The vehicle speed is compared with each wheel speed detected by each wheel speed sensor, and if any of the wheels is detected to be in a slip state, the brake fluid pressure for that wheel is reduced. We are trying to eliminate the slip condition.

``Problem to be Solved by the Invention'' As described above, since the anti-skid device detects a slip condition by detecting the difference in wheel speed of each wheel when the brake is applied, it may be detected due to a malfunction of the wheel speed sensor, for example. Even if it is possible to detect an abnormality in which the signal cannot be obtained completely, it can detect an abnormality in which the speed of one of the wheels is lower even though each wheel is rotating at the same speed. I couldn't do it.

"Means for Solving BM" In view of such circumstances, the present invention includes, as a first configuration, a plurality of wheel speed sensors each detecting the speed of a wheel;
The control device includes a heavy speed sensor that detects the running speed of the vehicle, and a control device that inputs detection signals from each of these sensors, and the control device controls the vehicle to run at a substantially constant speed based on the signals from the vehicle speed sensor. If it is detected that
The speed obtained by the ni speed sensor is used as a reference speed, and this is compared with the detected speed obtained from each wheel speed sensor, and if the error between the reference speed and the detected speed exceeds the allowable range, an abnormal signal is output. It is.

The present invention also provides a second configuration including a plurality of wheel speed sensors that detect the speed of each wheel, a constant speed sensor that detects that the vehicle is running at a substantially constant speed, and and a control device that inputs a detection signal from each wheel speed sensor, when the control device detects that the vehicle is running at a substantially constant speed based on the signal from the constant speed sensor. compare with each other,
An abnormal signal is output when the error between each signal exceeds a permissible range.

"Operation" According to the first configuration, the control device can detect that the vehicle is traveling at a substantially constant speed based on the signal from the vehicle speed sensor, and in this state, the control device can detect that the vehicle is traveling at a substantially constant speed. It can be determined that the wheel speeds are the same. In this state, the control device uses the speed obtained by the vehicle speed sensor as a reference speed and compares this with the detected speed obtained from each wheel speed sensor, and in this state, each detected speed is determined to match the reference speed. Therefore, if the error between the reference speed and the detected speed exceeds the allowable range, this is determined to be abnormal and an abnormal signal is output.

Further, according to a second configuration of the present invention, the control device includes:
It is possible to detect that the vehicle is traveling at a substantially constant speed based on the signal from the constant speed sensor, and therefore it can be determined that the wheel speeds of each wheel are the same in this state. In this state, the control device mutually compares the signals from the respective wheel speed sensors,
In this state, the signals from each wheel speed sensor should match each other, so if the error between the signals exceeds the allowable range, this is determined to be abnormal and an abnormal signal is output.

``Embodiment'' The present invention will be described below with reference to an illustrated embodiment. In FIG. 1, four wheel speed sensors 1 to 4 constituting a part of the undesired device are a front wheel on the right side, a front left side on the left side, and a rear wheel on the vehicle, respectively. The wheel speeds of the right and rear left wheels can be detected, and the signals detected by the wheel speed sensors 1 to 4 are input to the control device 5.

The control device 5 is configured to calculate an approximate vehicle speed that approximates the true vehicle speed based on the highest wheel speed among the wheel speeds detected by each of the wheel speed sensors 1 to 4 while the vehicle is braking. The approximate vehicle speed and the detection signals from the wheel speed sensors 1 to 4 are compared for each wheel. When a slip state in which the wheel speed of each wheel becomes smaller than the approximate vehicle speed by a predetermined amount is detected, a control signal is output to the depressurization signal generation circuits 11 to 14 to which the wheel in the slip state belongs, and Pressure reduction signals 21 to 24 for reducing brake fluid pressure are output.

Voltage subtraction signals 21 to 2 from the pressure reduction signal generation circuits 11 to 14
4 is output, a solenoid valve (not shown) is opened and the brake fluid pressure is reduced, thereby eliminating the slip condition of the wheel. If the slip state of the wheel is eliminated, the wheel speed of the wheel becomes close to the approximate vehicle speed, so the control device 5 controls the pressure reduction signal generation circuit 11.
The output of the pressure reduction signals 21 to 24 by 14 is stopped.

However, in this embodiment, a brake sensor 6 that detects the operating state of the brake, a rotation speed sensor 7 that detects the engine rotation speed, and a shift position sensor 8 that detects the gear shift position of the manual transmission are provided. The rotation speed sensor 7 and shift position sensor 8 constitute a vehicle speed sensor 9 that detects the traveling speed of the vehicle.

The control device 5 inputs detection signals from each sensor 6 to 8, and when the brake sensor 6 detects that the brake is not being applied, the rotation speed sensor 7
The running speed of the vehicle is calculated based on the engine rotational speed from the engine speed and the gear shift position from the shift position sensor 8.

As shown in FIG. 2, when it is determined that the calculated vehicle speed is maintained at a substantially constant speed for a certain period of time t, for example, 5 seconds, the calculated vehicle speed is changed to the reference speed 30.
The reference speed 30 is compared with the detected speeds 31 to 34 detected by each of the wheel speed sensors 1 to 4.

When the vehicle is running at a constant speed, the reference speed 30 and each of the detected speeds 31 to 34 should be substantially the same speed, so for example, the detected speed 34 obtained by the wheel speed sensor 4 is If the speed deviates significantly from the reference speed 30 beyond the allowable range, the control device 5 outputs an abnormality signal and lights up the warning light 10, and from now on,
Prevent the anti-skid device from operating. When such an abnormality occurs, each wheel speed sensor 1 to 4
In addition to the failure, there may be an abnormality in the vehicle speed sensor 9, an abnormality in tire air pressure, or the installation of emergency tires.

By the way, in the above embodiment, a vehicle speed sensor 9 that detects the running speed of the vehicle is used, which is composed of a rotation speed sensor 7 that detects the engine rotation speed, and a shift position sensor 8 that detects the gear shift position of the manual transmission. However, it is easier to install a deceleration sensor and
It may be detected that the vehicle has not been accelerated or decelerated for a certain period of time. In other words, instead of detecting the speed of the vehicle, it may be possible to simply detect whether the vehicle speed is substantially constant.

In this case, unlike the above embodiment, the reference speed is 30
However, when the vehicle is running at a constant speed, each of the detected speeds 31 to 34 should be substantially the same speed, so the speeds obtained by each wheel speed sensor to 4 should be mutually As can be understood from Fig. 2, if the error between the detected speed 34 obtained by the wheel speed sensor 4 and the other detected speeds 31 to 33 exceeds the allowable range, an abnormality occurs. It can be determined that

Further, instead of the deceleration sensor described above, a rotation speed sensor 7 that detects the engine rotation speed may be used to detect whether the vehicle speed is substantially constant, or the amount of depression of the accelerator pedal may be detected. It may be possible to detect whether the vehicle speed is substantially constant based on whether or not the vehicle speed remains substantially the same for a certain period of time.

In each of the embodiments described above, when detecting an abnormality in wheel speed, whether or not the steering wheel is located at the neutral position can also be included in the determination conditions.

[Effects of the Invention] As described above, according to the present invention, it is possible to extremely easily detect an abnormality in a wheel speed sensor, an abnormality in tire air pressure, or the attachment of an emergency tire.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing an example when an abnormality occurs. 1 to 4...Wheel speed sensor 5...Control device 6...
・Brake sensor 7...Rotation speed sensor 8...
Shift position sensor 9...Vehicle speed sensor 10...Warning lights 11-14...Decompression signal generation circuit 30...Reference speed 31-34...Detection speed Patent applicant Jidosha Kiki Co., Ltd.

Claims (2)

[Claims] (1) A plurality of wheel speed sensors each detecting the speed of the wheels, a vehicle speed sensor detecting the running speed of the vehicle, and a control device inputting detection signals from each of these sensors, the control device When it is detected that the vehicle is traveling at a substantially constant speed based on the signal from the vehicle speed sensor, the speed obtained by the vehicle speed sensor is used as a reference speed, and this is compared with the detected speed obtained from each wheel speed sensor, A wheel speed abnormality detection device characterized by outputting an abnormality signal when an error between a reference speed and a detected speed exceeds a permissible range. (2) A plurality of wheel speed sensors that each detect the speed of each wheel, a constant speed sensor that detects that the vehicle is running at a substantially constant speed, and a control device that inputs detection signals from each of these sensors. When the control device detects that the vehicle is traveling at a substantially constant speed based on the signals from the constant speed sensor, the control device compares the signals from each of the wheel speed sensors with each other, and calculates each signal. A wheel speed abnormality detection device characterized in that it outputs an abnormality signal when an error between the two exceeds a permissible range.