JP6071692B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  Vehicles such as automobiles are provided with wheel speed sensors that detect the wheel speeds of front, rear, left and right wheels. Then, based on the wheel speed of each wheel detected by the wheel speed sensor, for example, ABS (Antilock Brake System) control for preventing the wheel from being locked by braking is executed.

  If an abnormality occurs in the wheel speed sensor, control based on the wheel speed such as ABS control becomes impossible. Therefore, it is indispensable to diagnose whether an abnormality has occurred in the wheel speed sensor. As a method of this diagnosis, if the wheel acceleration is calculated by differentiating the wheel speed detected by the wheel speed sensor and the wheel acceleration is equal to or greater than a predetermined value, the wheel speed sensor is abnormal. A method of determining has been proposed.

JP 58-61052 A

  However, when the vehicle is traveling on a rough road, the bush of the lower arm is deformed / restored according to the unevenness of the road surface, and the wheel moves back and forth with respect to the vehicle body. Therefore, even if the vehicle body speed is constant, the wheel acceleration becomes a predetermined value or more, and it may be erroneously determined that an abnormality has occurred in the wheel speed sensor. As a countermeasure, it is conceivable to harden the bush. However, if the bush is hardened, the ride comfort of the vehicle is deteriorated.

  An object of the present invention is to provide a vehicle control device that can prevent erroneous output of wheel speed sensors from being erroneously output when the vehicle is traveling on a rough road without deteriorating the ride comfort of the vehicle. It is to be.

  In order to achieve the above object, a vehicle control device according to the present invention is a vehicle control device used in a vehicle having a structure in which a lower arm is connected to a vehicle body via a buffer member that is buffered by deformation. A wheel speed sensor for detecting a wheel speed of the wheel provided in the vehicle, a calculation means for calculating a wheel acceleration that is a time change rate of the wheel speed based on the wheel speed detected by the wheel speed sensor, An acceleration sensor that detects a vehicle body acceleration that is an acceleration; and an output unit that outputs an abnormality of the wheel speed sensor based on the wheel acceleration calculated by the calculation unit and the vehicle body acceleration detected by the acceleration sensor; The output means has a wheel acceleration calculated by the calculating means equal to or greater than a predetermined wheel acceleration threshold value, and the acceleration sensor If the vehicle acceleration is issued is below a predetermined vehicle acceleration threshold, and outputs an abnormality of the wheel speed sensors.

  When the wheel acceleration actually occurs, the wheel acceleration is transmitted to the vehicle body by the deformation and restoration of the buffer member, so that the vehicle body acceleration occurs.

  Therefore, if the vehicle acceleration is less than the predetermined vehicle acceleration threshold value but the wheel acceleration is greater than or equal to the predetermined wheel acceleration threshold value, an abnormality of the wheel speed sensor is output (the wheel speed sensor is abnormal). Is determined).

  In other words, even if the wheel acceleration is equal to or higher than the predetermined wheel acceleration threshold, if the vehicle acceleration is equal to or higher than the predetermined vehicle acceleration threshold, the wheel acceleration is actually generated. Is not output.

  Therefore, when the vehicle is traveling on a rough road such as an unpaved road without causing deterioration in the ride comfort of the vehicle due to the change in the hardness of the buffer member, an abnormality of the wheel speed sensor is erroneously output. Can be prevented.

  According to the present invention, it is possible to prevent erroneous output of the wheel speed sensor from being erroneously output when the vehicle is traveling on a rough road without deteriorating the riding comfort of the vehicle.

1 is a diagram schematically showing a main configuration of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied. It is a figure which shows the content of the abnormality determination process in hardware. It is a flowchart which shows the content of the abnormality determination process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically illustrating a main configuration of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied.

  The vehicle 1 is a four-wheeled vehicle, and includes a wheel 2 and a lower arm 3 at a left front part, a right front part, a left rear part, and a right rear part. Each lower arm 3 is supported by a vehicle body 5 via a rubber bush 4 so as to be rotatable about an axis extending in the front-rear direction.

  A wheel speed sensor 6 is provided in association with each wheel 2. The wheel speed sensor 6 includes, for example, a rotor made of a magnetic body that rotates with the rotation of the wheel 2 and an electromagnetic pickup provided in non-contact with the rotor. The electromagnetic pickup includes a magnetoresistive element (MR element). When the rotor rotates, the magnetic field changes with the rotation, and the resistance value of the magnetoresistive element of the electromagnetic pickup changes with the change of the magnetic field. This change in resistance value is converted into a pulse and output from the electromagnetic pickup as a wheel speed pulse.

  The vehicle body 5 is provided with an acceleration sensor 7 for detecting the longitudinal acceleration (vehicle body longitudinal G) generated in the vehicle body 5.

  In addition, a plurality of ABS ECUs (electronic control units) 8 having a configuration including a CPU and a memory are mounted on the vehicle 1. The ABS ECU 8 is supplied with wheel speed pulses output from the wheel speed sensors 6 and detection signals output from the acceleration sensor 7. The ABS ECU 8 executes ABS control for preventing the wheel 2 from being locked by braking based on those input signals, and for example, an abnormality for determining whether or not each wheel speed sensor 6 is abnormal. Execute the judgment process.

  FIG. 2 is a diagram showing the contents of the abnormality determination process in terms of hardware. FIG. 3 is a flowchart showing the contents of the abnormality determination process.

  The abnormality determination process is a software process executed by the ABS ECU 8. For example, while the ignition key switch of the vehicle 1 is turned on, the abnormality determination process is repeatedly executed for each wheel speed sensor 6 at a constant cycle.

  In the abnormality determination process, the cycle of the wheel speed pulse input from the wheel speed sensor 6 is measured, and the cycle is converted into the wheel speed (step S1). That is, by dividing the constant corresponding to the rotor by the cycle of the wheel speed pulse input from the wheel speed sensor 6, the wheel speed of the wheel 2 to be detected by the wheel speed sensor 6 is obtained.

  Next, a wheel acceleration that is a time change rate of the wheel speed is calculated (step S2). That is, the wheel acceleration, which is a differential value of the wheel speed, is obtained by differentiating the previously obtained wheel speed.

  Thereafter, the wheel acceleration is compared with a predetermined wheel acceleration threshold value Th1, and it is determined whether or not the wheel acceleration is greater than or equal to the wheel acceleration threshold value Th1. On the other hand, the vehicle longitudinal G detected by the acceleration sensor 7 is compared with a predetermined vehicle acceleration threshold Th2, and it is determined whether the vehicle longitudinal G is less than the vehicle acceleration threshold Th2.

  If both determinations are affirmed, that is, if the AND condition that the wheel acceleration is greater than or equal to the wheel acceleration threshold Th1 and the vehicle longitudinal G is less than the vehicle acceleration threshold Th2 is satisfied (step (YES in S3), the count value of the abnormality determination number counter that counts the number of times that the wheel speed sensor 6 has been determined to be abnormal (abnormality determination number) is incremented (+1) (step S4).

  When the count value of the abnormality determination number counter is incremented, it is determined whether or not the incremented count value has reached a predetermined value (a natural number of 1 or more) (step S5).

  When the count value of the abnormality determination counter reaches a predetermined value (YES in step S5), it is determined that an abnormality has occurred in the wheel speed sensor 6, and the abnormality is stored in the ABS ECU 8 as a result of diagnosis. Stored (diag output). When it is determined that an abnormality has occurred in any one of the wheel speed sensors 6, a caution lamp provided on the meter panel is turned on (step S6), and the abnormality determination process is terminated.

  On the other hand, if at least one of the determination as to whether the wheel acceleration is equal to or greater than the wheel acceleration threshold Th1 and the determination as to whether the vehicle longitudinal G is less than the vehicle acceleration threshold Th2 is denied, that is, the wheel If the AND condition that the acceleration is greater than or equal to the wheel acceleration threshold Th1 and the vehicle longitudinal G is less than the vehicle acceleration threshold Th2 is not satisfied (NO in step S3), the wheel speed sensor 6 is operating normally. It is determined that it is operating, and the abnormality determination process is terminated.

  When the vehicle 1 is traveling on a rough road such as an unpaved road and wheel acceleration actually occurs, the wheel acceleration is transmitted to the vehicle body 5 due to deformation and restoration of the bush 4. G is generated.

  In the abnormality determination process, if the wheel acceleration is equal to or greater than the predetermined wheel acceleration threshold Th1 even though the vehicle longitudinal G is less than the predetermined vehicle acceleration threshold Th2, the wheel speed sensor 6 is abnormal. It is determined that it has occurred. When the number of times determined to be abnormal reaches a predetermined value, an abnormality of the wheel speed sensor 6 is output.

  In other words, even if the wheel acceleration is equal to or greater than the predetermined wheel acceleration threshold Th1, if the vehicle longitudinal G is equal to or greater than the predetermined vehicle acceleration threshold Th2, the wheel acceleration actually occurs. Abnormality of sensor 6 is not output.

  Therefore, when the vehicle 1 is traveling on a rough road such as an unpaved road without causing deterioration of the riding comfort of the vehicle 1 by changing the hardness of the bush 4, the abnormality of the wheel speed sensor 6 is erroneous. Can be prevented.

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, the abnormality determination process may be executed by an ECU other than the ABS ECU 8 mounted on the vehicle 1. In this case, the wheel speed pulse output from each wheel speed sensor 6 and the detection signal output from the acceleration sensor 7 may be directly input to the ECU that executes the abnormality determination process. The wheel speed pulse output from the vehicle and the detection signal output from the acceleration sensor 7 may be input via the ABS ECU 8.

  Further, the determination process may be executed in cooperation with the ABS ECU 8 mounted on the vehicle 1 and another ECU. For example, the wheel speed pulse output from each wheel speed sensor 6 is input to the ABS ECU 8, the wheel acceleration of each wheel 2 is obtained by the ABS ECU 8, the obtained wheel acceleration and the detection signal output from the acceleration sensor 7. Is input to another ECU, and the ECU compares the wheel acceleration with a predetermined wheel acceleration threshold value Th1 and compares the vehicle body longitudinal G with a predetermined vehicle body acceleration threshold value Th2. Based on the result, it may be determined whether or not an abnormality has occurred in the wheel speed sensor 6.

  In addition, various design changes can be made within the scope of matters described in the claims.

1 Vehicle 2 Wheel 3 Lower arm 4 Bush (buffer member)
5 Body 6 Wheel speed sensor 7 Acceleration sensor 8 ABS ECU (calculation means, output means)

Claims (1)

A vehicle control device used in a vehicle having a structure in which a lower arm is connected to a vehicle body via a buffer member that cushions by deformation,
A wheel speed sensor for detecting a wheel speed of a wheel provided in the vehicle;
Calculation means for calculating a wheel acceleration that is a temporal change rate of the wheel speed based on the wheel speed detected by the wheel speed sensor;
An acceleration sensor for detecting a vehicle body acceleration which is an acceleration of the vehicle body;
Output means for outputting an abnormality of the wheel speed sensor based on the wheel acceleration calculated by the calculating means and the vehicle body acceleration detected by the acceleration sensor;
The output means is when the wheel acceleration calculated by the calculation means is equal to or greater than a predetermined wheel acceleration threshold and the vehicle acceleration detected by the acceleration sensor is less than a predetermined vehicle acceleration threshold. A vehicle control device that outputs an abnormality of the wheel speed sensor.

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