JP2009128239A - Device and method for judging fault of vehicle speed sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a reliability improvement in fault judgment of a vehicle speed sensor by preventing misjudgment of failure of the vehicle speed sensor. <P>SOLUTION: A device for judging a fault of the vehicle speed sensor includes: wheel speed sensors 13, 14 for detecting a wheel rotation speed; the vehicle speed sensor 15 for detecting a traveling speed of a vehicle from a rotation speed of a drive shaft 4 of the vehicle; a fault judgment means 10 for judging fault of the vehicle speed sensor 15 based on information obtained the wheel speed sensors 13, 14 and the vehicle speed sensor 15; a vehicle behavior control means for controlling behavior of the vehicle by controlling the wheel rotation speed. A fault judgment means 10 is composed so as to determine that the vehicle speed sensor 15 fails when every condition that the wheel speed sensors 13, 14 are normal, an absolute value of a difference between a vehicle speed obtained from the wheel speed sensors 13, 14 and a vehicle speed obtained with the vehicle speed sensor 15 is a prescribed value or more, and the vehicle behavior control mean is in non-operation is wholly satisfied, and when materialization of all conditions continues for a prescribed time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle speed sensor failure determination apparatus and failure determination method suitable for use in vehicles such as automobiles.

  In recent years, a vehicle speed limiting device that limits the traveling speed of a vehicle to a predetermined upper limit vehicle speed, an auto cruise device that automatically controls the fuel injection amount, the throttle opening, etc. so that the vehicle travels while maintaining a constant vehicle speed, Various devices have been put into practical use, such as a slope start assist device that maintains brake fluid pressure and facilitates start of a slope even when the brake pedal is released after the brake pedal is depressed at a vehicle speed of 0.

In such an apparatus, the current vehicle speed is detected by a vehicle speed sensor, and control is executed based on the detected vehicle speed information, and accurate vehicle speed detection is an essential condition. For this reason, when the vehicle speed sensor fails or is abnormal, it is necessary to promptly cancel the control of the device using the vehicle speed information in order to stabilize the behavior of the vehicle.
However, in the vehicle speed limiting device, if the control is simply canceled when the vehicle speed sensor is abnormal, it may be allowed to travel above the upper limit vehicle speed and become incompatible with the law. Based on the above, a backup process is performed to limit the engine speed so as to be lower than the upper limit vehicle speed.

  Here, an example of a vehicle speed sensor failure determination (abnormality determination) method will be described with reference to FIGS. As shown in FIG. 2 (a), the engine 1 is mounted on the vehicle 1, and the rotational driving force from the engine 2 is driven through a transmission 3, a propeller shaft 4, a differential gear (diff) 5, and a drive shaft 6. To the left and right rear wheels.

  A vehicle speed sensor 15 is attached to the transmission 3. As shown in the figure, the vehicle speed sensor 15 is connected to a control unit (ABS-ECU in this example) 7, and information obtained by the vehicle speed sensor 15 is output to the ABS-ECU 7. The ABS-ECU 7 is connected to other ECUs (for example, transmission ECU, engine ECU, etc.) (not shown) so that they can communicate with each other, and information such as the current gear is input.

Here, the vehicle speed sensor 15 directly detects the rotational speed of the output shaft (propeller shaft) 4 of the transmission 3, and the ECU 7 detects the rotational speed of the output shaft obtained by the vehicle speed sensor 15 and the differential gear. The vehicle travel speed (vehicle speed) is calculated from the gear ratio (final reduction ratio) and the dynamic radius of the drive wheels RL and RR.
Further, as shown in the drawing, wheel speed sensors 11 to 14 capable of detecting the rotational speed of the wheels are provided in the vicinity of the left and right front wheels FL and FR and the left and right rear wheels RL and RR, respectively. The wheel speed information obtained by these wheel speed sensors 11-14 is also input to the ABS-ECU 7, and the operation of the ABS, the traction control device, etc. is controlled based on the information from each wheel speed sensor 11-14. It has become so.

Although not shown, the ABS-ECU 7 is provided with a failure determination unit that determines a failure (failure, abnormality) of the vehicle speed sensor 15, and as shown in FIG. If it is established at the same time and the state continues for a predetermined time (for example, 2 seconds) or more, it is determined that the vehicle speed sensor 15 has failed.
-The wheel speed sensors 11-14 are normal.
| V _AV −V _S | ≧ specified value (where V _AV is an average value of vehicle speed obtained from the wheel speed sensors 11 to 15 and V _S is a vehicle speed obtained by the vehicle speed sensor 15).
That is, since the vehicle speed can be detected by adding the tire moving radius to the information from the wheel speed sensors 11 to 14, the vehicle speed V _AV obtained from the wheel speed sensors 11 to 14 and the vehicle speed sensor 15 can be obtained. The vehicle speed V _S is compared, and if these two vehicle speeds are greatly deviated, it is determined that the vehicle speed sensor 15 has failed. The first condition is a precondition for performing the fail determination, and the normal determination of the wheel speed sensors 11 to 14 is separately executed by a known logic in the ABS-ECU 7.

In the second condition, the average value of the vehicle speeds V _{FL to} V _RR obtained from the wheel speed sensors 11 to 14 is used as the vehicle speed V _AV obtained from the wheel speed sensor.
Patent Document 1 below discloses a technique for determining a failure of a vehicle speed sensor by the same method as described above.
Japanese Utility Model Publication No. 63-23650

However, in the conventional technology for comparing the information from the wheel speed sensor and the vehicle speed sensor to determine the failure of the vehicle speed sensor, depending on the driving situation, the vehicle speed sensor is functioning normally, but the failure is erroneous. It may be judged. For example, when the inner wheel floats on a curve, only one wheel slips on a slippery road surface, or when the vehicle runs on a running tester in which only the driving wheel rotates, the above-described divergence between V _AV and V _S is large. Therefore, there is a possibility that the vehicle speed sensor 15 is erroneously determined to have failed.

  The present invention was devised in view of such a problem, and a vehicle speed sensor failure determination device and a failure which are intended to improve the reliability of vehicle speed sensor failure determination by preventing erroneous determination of vehicle speed sensor failure. An object is to provide a determination method.

  For this reason, the failure determination device for a vehicle speed sensor according to the present invention includes a wheel speed sensor that detects a wheel rotation speed of the vehicle, a vehicle speed sensor that detects a travel speed of the vehicle from the rotation speed of the drive shaft of the vehicle, and the wheel Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the speed sensor and information obtained from the vehicle speed sensor, and the vehicle by individually controlling the rotational speed or driving force of the wheels Vehicle behavior control means for controlling the behavior of the vehicle, and the failure determination means includes a vehicle speed calculated based on information from the wheel speed sensor, a vehicle speed obtained by the vehicle speed sensor, and a vehicle speed obtained by the vehicle speed sensor. If all the conditions that the absolute value of the difference between the two is equal to or greater than the predetermined value and the vehicle behavior control means is inactive are satisfied and all the conditions are satisfied for a predetermined time, it is determined that the vehicle speed sensor has failed. Features Claim 1).

  In addition, the vehicle speed sensor failure determination apparatus according to the present invention includes a wheel speed sensor that detects a wheel rotation speed of a vehicle, a vehicle speed sensor that detects a travel speed of the vehicle from the rotation speed of the drive shaft of the vehicle, and the wheel speed. Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the sensor and information obtained from the vehicle speed sensor, and individually controlling the rotational speed or driving force of the wheel to control the vehicle Vehicle behavior control means for controlling the behavior, and the failure determination means is configured such that the wheel speed sensor is normal, the vehicle speed calculated based on information from the wheel speed sensor, and the vehicle speed obtained by the vehicle speed sensor. All the conditions that the absolute value of the difference is equal to or greater than the first predetermined value, the absolute value of the acceleration of the vehicle is equal to or smaller than the second predetermined value, and the vehicle behavior control means is not operating are satisfied, and all the conditions are satisfied for a predetermined time. Then, the vehicle speed sensor It is characterized in that determined to be (claim 2).

  In addition, the vehicle speed sensor failure determination device of the present invention includes a wheel speed sensor that detects the rotational speeds of the left and right wheels of the vehicle, a vehicle speed sensor that detects the traveling speed of the vehicle from the rotational speed of the drive shaft of the vehicle, Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the wheel speed sensor and information obtained from the vehicle speed sensor, and individually controlling the rotational speed or driving force of the wheel Vehicle behavior control means for controlling the behavior of the vehicle by means of the vehicle, and the failure determination means obtains the vehicle speed calculated based on information from each wheel speed sensor and the vehicle speed sensor. The absolute value of the difference between the measured vehicle speed is equal to or greater than the first predetermined value, the absolute value of the acceleration of the vehicle is equal to or smaller than the second predetermined value, and the absolute value of the difference between the vehicle speeds of the left and right wheels obtained from the left and right wheel speed sensors. Is below the third predetermined value Each condition vehicle behavior control means that in a non-actuated all met, and the establishment of all the conditions are continued for a predetermined time, and determining means determines that the vehicle speed sensor is faulty (claim 3).

  In addition, the vehicle speed sensor failure determination device of the present invention includes a wheel speed sensor that detects the rotational speeds of the left and right wheels of the vehicle, a vehicle speed sensor that detects the traveling speed of the vehicle from the rotational speed of the drive shaft of the vehicle, Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the wheel speed sensor and information obtained from the vehicle speed sensor, and individually controlling the rotational speed or driving force of the wheel Vehicle behavior control means for controlling the behavior of the vehicle by means of the vehicle, and the failure determination means obtains the vehicle speed calculated based on information from each wheel speed sensor and the vehicle speed sensor. The absolute value of the difference between the measured vehicle speed is equal to or greater than the first predetermined value, the absolute value of the acceleration of the vehicle is equal to or smaller than the second predetermined value, and the absolute value of the difference between the vehicle speeds of the left and right wheels obtained from the left and right wheel speed sensors. Is below the third predetermined value All the conditions that the average value of the vehicle speeds of the left and right wheels obtained from the left and right wheel speed sensors is not less than the fourth predetermined value and the vehicle behavior control means is inactive are satisfied, and all the conditions are satisfied for a predetermined time. Then, it is determined that the vehicle speed sensor has failed (claim 4).

The wheel speed sensor preferably detects the rotational speed of the drive wheel of the vehicle.
The acceleration is preferably a differential value of the vehicle speed calculated based on information from the wheel speed sensor.
The failure determination method for a vehicle speed sensor according to the present invention includes a vehicle speed sensor for detecting a traveling speed of the vehicle based on information from a wheel speed sensor for detecting a wheel rotational speed of the vehicle and a rotational speed of a drive shaft of the vehicle. A determination method for determining failure of the vehicle speed sensor based on information, the wheel speed sensor being normal, a vehicle speed calculated based on information from the wheel speed sensor, and a vehicle speed obtained by the vehicle speed sensor, If all the conditions that the absolute value of the difference between the two is greater than the predetermined value and the vehicle behavior control means for controlling the behavior of the vehicle is inactive are satisfied and all the conditions are satisfied for a predetermined time, the vehicle speed sensor breaks down. It is characterized in that it is determined (claim 7).

  According to the vehicle speed sensor failure determination device and failure determination method of the present invention, it is possible to prevent erroneous determination of a failure of the vehicle speed sensor and to improve the reliability of failure determination of the vehicle speed sensor. In particular, when the vehicle behavior control means is not operating, it is estimated that each wheel rotates stably. In this situation, the vehicle speed obtained by the wheel speed sensor and the vehicle speed obtained by the vehicle speed sensor The vehicle speed sensor failure is determined when the deviation from the vehicle is greater than or equal to a predetermined value, and the failure determination is prohibited when the vehicle behavior control means is operating, thereby improving the reliability of the vehicle speed sensor failure determination. (Claims 1 and 7).

In addition, since the fact that the vehicle acceleration is equal to or less than the second predetermined value is added to the condition for failure determination, failure determination is prohibited when the vehicle acceleration is greater than the second predetermined value. Therefore, adverse effects caused by differences in filtering processing applied to the vehicle speed sensor and the wheel speed sensor can be eliminated as much as possible, and the reliability of the vehicle speed sensor failure determination is also improved (claim 2).
Further, since the absolute value of the difference between the vehicle speeds of the left and right wheels obtained from the left and right wheel speed sensors is equal to or less than the third predetermined value, it is added to the failure determination condition. If it exceeds, failure judgment is prohibited. Therefore, the vehicle speed sensor failure determination is prohibited when the steering angle is large such as a sharp curve or when one wheel is slipping, and the reliability of the vehicle speed sensor failure determination is improved. Item 3).

  In addition, since the fact that the vehicle speed average value of the left and right wheels obtained from the left and right wheel speed sensors is greater than or equal to the fourth predetermined value is added to the failure determination condition, the vehicle speed average value is less than or equal to the fourth predetermined value. Failure judgment during low speed driving is prohibited. Therefore, the failure determination of the vehicle speed sensor at a low vehicle speed that cannot ensure the detection accuracy of the wheel speed sensor can be prohibited, and the reliability of the failure determination of the vehicle speed sensor is also improved.

  In addition, since the rotational speed of the drive wheel has a stronger correlation with the output value of the vehicle speed sensor than the non-drive wheel, the vehicle speed sensor failure determination is performed using the vehicle speed obtained by the wheel speed sensor on the drive wheel side. By executing, the accuracy of the vehicle speed sensor failure determination is improved. In particular, it is possible to avoid a situation in which it is erroneously determined that the vehicle speed sensor has failed in a situation where only the drive wheels rotate, such as a test run on a running tester.

  In addition, the vehicle speed calculated based on the information from the wheel speed sensor rather than the information from the vehicle speed sensor is differentiated to obtain the vehicle acceleration, thereby improving the accuracy of the vehicle speed sensor failure determination. That is, when the vehicle speed obtained by the vehicle speed sensor is differentiated and used as acceleration, if acceleration exceeding the second predetermined value is always output due to failure of the vehicle speed sensor, it is determined that the vehicle speed sensor has failed. Failure determination itself is prohibited, and failure of the vehicle speed sensor cannot be correctly determined. Therefore, by calculating the vehicle acceleration based on the information from the wheel speed sensor, such a situation can be avoided and the reliability of the vehicle speed sensor failure determination can be improved.

Hereinafter, a vehicle speed sensor failure determination device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a schematic block diagram showing the configuration, and FIG. FIG.
The hardware of the vehicle 1 shown in FIG. 1A is basically configured in the same manner as described with reference to FIG. That is, the engine 1 is mounted on the vehicle 1, and the rotational driving force from the engine 2 passes through the transmission 3, the propeller shaft (drive shaft) 4, the differential gear (diff) 5, and the drive shaft 6. It is transmitted to the rear wheels RR and RL.

  A vehicle speed sensor 15 is attached to the transmission 3, and information obtained by the vehicle speed sensor 15 is output to the ABS-ECU 7. Further, as shown in the drawing, wheel speed sensors 11 to 14 capable of detecting the rotational speed of the wheels are provided in the vicinity of the left and right front wheels FL and FR and the left and right rear wheels RL and RR, respectively. Information of 11 to 14 is input to the ABS-ECU 7.

  The vehicle 1 also has a vehicle behavior control system or vehicle behavior control means (not shown) that controls the behavior of the vehicle 1 by individually controlling the rotational speed or driving force of the wheels FL, FR, RL, RR. Is provided. Here, specifically, the vehicle behavior control system is an ABS (anti-lock brake system) that temporarily weakens the braking force of the wheel that is locked during braking to prevent the wheel from being locked, or is idling. ASR (anti-spin regulator) that applies braking force to the wheel to prevent the wheel from slipping, VSC (vehicle stability control) that prevents the vehicle from slipping when turning, and improves running stability, This corresponds to an active type brake system in which an obstacle is recognized by a laser radar or the like to avoid a collision.

The above-described ABS-ECU 7 is provided as a main part of such a vehicle behavior control system. The ABS-ECU 7 operates the vehicle behavior control means mainly based on wheel speed information from the wheel speed sensors 11-14. In this embodiment, an automatic transmission is applied to the transmission (transmission) 3. For this reason, the vehicle 1 is provided with a T / M-ECU 8 for controlling the operation of the transmission 3. The transmission 3 is provided with a gear position sensor 9 for detecting the current gear position, and detection information from the gear position sensor 9 is input to the T / M-ECU 8. The ABS-ECU 7 and the T / M-ECU 8 are connected to each other via a communication line such as CAN so that information can be exchanged between them.

The vehicle speed sensor 15 directly detects the rotational speed of the output shaft (propeller shaft) 4 of the transmission 3, and the ABS-ECU 7 determines the output shaft rotational speed obtained by the vehicle speed sensor 15 and the differential. The vehicle traveling speed (vehicle speed) V _S is obtained from the gear ratio (final reduction ratio) in the gear and the tire moving radius of the drive wheels RL and RR.
Further, in addition to the above-described vehicle speed V _S , the ABS-ECU 7 determines each of the drive wheels RL, RR based on the wheel speed rotation speed obtained from the wheel speed sensors 13, 14 and the tire moving radius for determining the failure of the vehicle speed sensor 15. The vehicle speeds V _RL and V _{RR at} are calculated.

  Next, the main part of the present invention will be described. The ABS-ECU 7 is provided with a failure determination unit (failure determination means) 10 that performs failure determination of the vehicle speed sensor 15. Here, the failure determination unit 10 is a functional part constructed by software, and executes failure determination control of the vehicle speed sensor 15 every predetermined control cycle. When the failure determination unit 10 determines that the vehicle speed sensor 15 is defective or abnormal, various controls using the vehicle speed sensor 15 are canceled, and backup processing of various devices is performed as necessary. It has become.

Further, the failure determination unit 10 determines that the vehicle speed sensor 15 has failed when all of the following conditions 1 to 7 are satisfied and the state continues for a predetermined time (for example, 2 seconds).
1. 1. Wheel speed sensors 13 and 14 are normal. 2. Vehicle behavior control system (ABS, ASR, VSC, etc.) is not operating. 3. The transmission is not shifting. | Vehicle acceleration (vehicle speed differential value) | ≤0.1G (second predetermined value)
5). | V _RR −V _RL | ≦ 5 km / h (third predetermined value),
6). (V _RL + V _RR ) / 2 ≧ 20 km / h (fourth predetermined value)
7). | (V _RL + V _RR ) / 2−V _S | ≧ 10 km / h (first predetermined value)
Of the above, conditions 1 to 6 are conditions that satisfy that the vehicle 1 is substantially straight and is in a steady travel state, and whether or not the travel state is suitable for executing a failure determination of the vehicle speed sensor 15. It is a condition for judging. Further, the condition for determining whether or not the vehicle speed sensor 15 has actually failed is 7, and if any one of the conditions 1 to 6 is not satisfied, the failure determination of the vehicle speed sensor 15 is not executed. . That is, it can be said that the conditions 1 to 6 are conditions for permitting or prohibiting the failure determination of the vehicle speed sensor 15.

Now, the reason why each condition is set will be described below. First, condition 1 is provided as the most basic precondition for determining the failure of the vehicle speed sensor 15. The failure determination of the wheel speed sensors 13 and 14 is performed in the ABS-ECU 7 by a known logic independent from the failure determination of the vehicle speed sensor 15.
Here, in the failure determination unit 10, the vehicle speed calculated from the wheel speed sensor is compared with the vehicle speed obtained by the vehicle speed sensor 15 as in the conventional technique, and the failure of the vehicle speed sensor 15 is determined based on the comparison result. Judgment is made. However, the average value of all the wheel speed sensors 11 to 14 is conventionally used for determining the failure of the vehicle speed sensor 15, whereas in the present embodiment, the wheel speed sensor 13 on the driving wheel (rear wheel in this case) side. , 14 is used only, and information from the wheel speed sensors 11, 12 of the non-driven wheels (front wheels) is not referred to. Therefore, in condition 1, it is determined whether or not the wheel speed sensors 13 and 14 on the drive wheel side are normal.

  This is because the vehicle speed sensor 15 calculates the vehicle speed based on the rotational speed of the output shaft of the transmission, and the vehicle speed obtained from the wheel speed sensors 13 and 14 of the drive wheels is the wheel speed of the non-drive wheels. This is because the vehicle speed sensor 15 has a stronger correlation with the output value of the vehicle speed sensor 15 than the vehicle speed obtained from the sensors 13 and 14. Then, by using only the information of the wheel speed sensors 13 and 14 of the drive wheels in this way, when the vehicle 1 is driven by a running tester, the vehicle speed obtained by the wheel speed sensors 13 and 14 and the vehicle speed sensor 15 are used. It is possible to prevent a large deviation from occurring in the obtained vehicle speed.

Of course, if any one of the wheel speed sensors 13 and 14 is abnormal, the condition 1 is not satisfied, and the failure determination of the vehicle speed sensor 15 is prohibited.
Next, the condition 2 will be described. When the vehicle behavior control system (ABS or the like) as described above is operating, it can be considered that the wheel speed changes irregularly and the wheel speed change is remarkable. Under such circumstances, the actual vehicle speed cannot be calculated correctly from the wheel speed sensors 13 and 14. Therefore, condition 2 is provided, and when it is determined that the vehicle behavior control system is operating, failure determination of the vehicle speed sensor 15 is not performed.

  Condition 3 prohibits the failure determination of the vehicle speed sensor 15 during the shift in consideration of the influence of the torsional vibration of the propeller shaft 4 during the shift. That is, the propeller shaft 4 changes the presence / absence of torque transmission from the engine 1 each time the clutch is connected / disconnected, which causes the propeller shaft 4 to torsionally vibrate, and the vehicle speed obtained from the vehicle speed sensor 15 is significant. Change. Further, since the vehicle speed change state is greatly different from the actual vehicle speed, if the vehicle speed determination is performed during the shift, the reliability of the failure determination is greatly impaired. For this reason, failure determination is prohibited when the transmission 3 is shifted. It should be noted that such information regarding the speed change of the transmission 3 is obtained through communication (CAN communication) with the T / M-ECU 8.

  Condition 4 is to prohibit failure determination of the vehicle speed sensor 15 in a transient state where the vehicle is accelerating (including decelerating). This is because the wheel speed sensors 13 and 14 and the vehicle speed sensor 15 perform the filtering process for noise removal when outputting the detection information to the ABS-ECU 7, and eliminate the influence of the filtering process. For this purpose, condition 4 is provided.

  Here, there are many cases where the sensor filtering method has know-how for each manufacturer of the sensor and is not disclosed, and the vehicle speed sensor 15 and the wheel speed sensors 13 and 14 may have different filtering processing methods. If the filtering processing methods are different in this way, the vehicle speed obtained from both sensors may be greatly deviated in the case of sudden acceleration or sudden deceleration due to this. Therefore, when the absolute value of acceleration exceeds 0.1 G (second predetermined value), vehicle speed determination is prohibited.

Since this device is a device for determining failure of the vehicle speed sensor 15, the acceleration used in the condition 4 is not obtained from the vehicle speed obtained by the vehicle speed sensor 15, but is obtained by the wheel speed sensors 13, 14. In this embodiment, the acceleration is calculated by differentiating the average value of the vehicle speeds obtained by the two sensors 13 and 14.
That is, when the vehicle speed obtained by the vehicle speed sensor 15 is differentiated and used as an acceleration, if an acceleration exceeding the second predetermined value is always output due to a failure of the vehicle speed sensor 15, it is determined that the vehicle speed sensor 15 has failed. Therefore, the failure determination itself is prohibited before the vehicle speed sensor 15 can be correctly failed. Therefore, in condition 4, vehicle acceleration is calculated based on information from the wheel speed sensors 13 and 14.

Condition 5 is a condition provided to eliminate a case where the steering angle such as a sharp curve is large or a situation where one wheel is slipping. The vehicle speeds V _RL and V _RR obtained by the wheel speed sensors 13 and 14 are the conditions. If the difference between the left and right wheels becomes greater than, for example, 5 km / h (third predetermined value), failure determination is prohibited.
Condition 6 is a condition for determining whether or not the vehicle is traveling at a traveling speed at which the vehicle speed can be reliably detected. That is, since the detection accuracy of the vehicle speed sensor 15 and the wheel speed sensors 13 and 14 decreases at an extremely low speed, the vehicle speed obtained from the left and right wheel speed sensors (here, the average value of the vehicle speeds of the left and right wheels) is 20 km / h. If it falls below (fourth predetermined value), it is determined that the accuracy of the sensor cannot be secured, and the failure determination of the vehicle speed sensor 15 is prohibited. The fourth predetermined value may be equal to or higher than the minimum speed at which the detection accuracy of the wheel speed sensors 13 and 14 is guaranteed.

Although the conditions 1 to 6 have been described above, these conditions are conditions for executing the failure determination of the vehicle speed sensor 15, and are not conditions for determining whether or not the vehicle speed sensor 15 is failing.
Therefore, Condition 7 is provided as a condition for determining whether or not the vehicle speed sensor 15 is actually failing. Hereinafter, condition 7 will be described. This condition determines whether or not the deviation between the vehicle speed obtained from the wheel speed sensors 13 and 14 and the vehicle speed obtained by the vehicle speed sensor 15 is within a predetermined range. Specifically, whether the absolute value of the difference between the average value of the vehicle speeds of the left and right drive wheels and the vehicle speed obtained by the vehicle speed sensor 15 is a predetermined value (first predetermined value; for example, 10 km / h or more). Determine.

When all of these conditions 1 to 7 are satisfied, it is determined that the vehicle speed sensor 15 is out of order. However, in order to eliminate the influence of temporary noise and the like, it is determined whether or not a state where all of these conditions 1 to 7 are satisfied continues for a predetermined time (for example, 2 seconds). It is determined that the sensor 15 has failed.
Since the vehicle speed sensor failure determination apparatus according to an embodiment of the present invention is configured as described above, the failure determination method will be described as follows.

First, it is determined whether or not the wheel speed sensors 13 and 14 are normal. If the wheel speed sensors 13 and 14 are abnormal, the failure determination routine is terminated. If it is normal, it is determined whether the vehicle behavior control system (ABS, ASR, VSC, etc.) is not operating based on information in the ABS-ECU 7. If it is in operation, this failure determination routine is terminated. If it is not in operation, it is determined based on information from the T / M-ECU 8 whether the transmission is in non-shifting. Similarly, the vehicle acceleration (vehicle speed differential value) is 0.1 G (second predetermined value) or less, and the absolute value of the difference between the left and right wheel vehicle speeds obtained by the wheel speed sensors 13 and 14 is 5 km / h (third predetermined value). Value) Hereinafter, it is determined whether or not the average value of the vehicle speeds of the left and right wheels obtained by the wheel speed sensors 13 and 14 is 20 km / h (fourth predetermined value) or more, and these conditions (conditions 1 to 6) are all If established, whether the difference between the vehicle speed [(V _RL + V _RR ) / 2] obtained from the wheel speed sensors 13 and 14 and the vehicle speed V _S obtained by the vehicle speed sensor 15 is 10 km / h (first predetermined value). Determine whether or not. When it is determined that all of these conditions are satisfied and the predetermined time has continued, it is determined that the vehicle speed sensor 15 has failed.

If a failure of the vehicle speed sensor 15 is determined, for example, an indicator lamp or the like is lit on a meter panel or the like to notify the driver of the abnormality of the vehicle speed sensor 15, and control using the vehicle speed sensor 15 is canceled, which is necessary. Backup processing is executed.
As described above in detail, according to the vehicle speed sensor failure determination device according to the embodiment of the present invention, the vehicle speed sensor failure determination condition is based on the condition that the vehicle behavior system in which the wheel speed changes rapidly is inactive. In addition, it is possible to prevent erroneous determination of the failure of the vehicle speed sensor 5, and there is an advantage that the reliability of failure determination of the vehicle speed sensor 15 is greatly improved. In addition, since this device only needs to add control logic to the conventional failure determination device, it can be realized with a simple configuration and at low cost.

In addition, since the fact that the transmission 3 is not shifting is added to the condition for failure determination, the influence of torsional vibration of the propeller shaft 4 at the time of shifting can be eliminated. From this point also, the reliability of failure determination of the vehicle speed sensor 15 is reliable. improves.
Further, the fact that the vehicle acceleration is equal to or less than a predetermined value (second predetermined value) is added to the failure determination condition, and if the vehicle acceleration is greater than the second predetermined value, the failure determination is prohibited. , 14 can be eliminated as much as possible due to the difference in the filtering processing applied to..

Further, in addition to the failure determination condition, the absolute value | V _RR −V _RL | of the difference between the vehicle speeds of the left and right wheels obtained from the wheel speed sensors 13 and 14 is equal to or less than a predetermined value (third predetermined value). If this absolute value exceeds the third predetermined value, failure determination is prohibited, so failure determination of the vehicle speed sensor 15 is prohibited when the steering angle is large or when one wheel is slipping. Therefore, the reliability of the failure determination of the vehicle speed sensor 15 is also improved.

Further, it is added to the condition for failure determination that the average value [(V _RL + V _RR ) / 2] of the respective vehicle speeds in the left and right wheels obtained from the wheel speed sensors 13 and 14 is not less than a predetermined value (fourth predetermined value). Therefore, failure determination during low-speed traveling with the vehicle speed average value being the fourth predetermined value or less is prohibited. Therefore, the failure determination of the vehicle speed sensor 15 at a low vehicle speed where the detection accuracy of the wheel speed sensors 13 and 14 cannot be ensured can be prohibited, and the reliability of the failure determination of the vehicle speed sensor 15 is also improved.

  Further, since the rotational speeds of the drive wheels RL and RR have a stronger correlation with the output value of the vehicle speed sensor than the non-drive wheels FL and FR, the wheel speed sensors 13 and 13 provided on the drive wheels RL and RR, By using the vehicle speed calculated based on the information from 14, the accuracy of the failure determination of the vehicle speed sensor 15 is improved, which further contributes to the improvement of reliability. Further, it is possible to avoid a situation in which it is erroneously determined that the vehicle speed sensor 15 has failed when traveling on the running tester.

  While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, as a condition for determining the failure of the vehicle speed sensor 15, at least the condition 1, the condition 2, and the condition 7 may be used among the above conditions 1 to 7, and other conditions are not considered when determining the failure of the vehicle speed sensor 15. May be. Further, any one of the other conditions 3 to 6 may be applied to conditions 1, 2, and 7 alone or in appropriate combination.

  Moreover, in this embodiment, although the failure determination part 10 which determines the failure of the vehicle speed sensor 15 is provided in ABS-ECU7, it is performing, However, The failure determination part 10 may be provided in other ECU, It may be provided alone. Furthermore, although an automatic transmission is applied as the transmission 3 in this embodiment, a manual transmission may be applied. In this case, “shifting” may be read as “clutch disengagement” and “non-shifting” as “clutch engagement”.

It is a figure which shows the failure determination apparatus of the vehicle speed sensor which concerns on one Embodiment of this invention. It is a figure explaining the prior art.

Explanation of symbols

1 Vehicle 2 Engine 3 Transmission (Transmission)
4 Propeller shaft (drive shaft)
10 Failure determination unit (failure determination means)
11-14 Wheel speed sensor 15 Vehicle speed sensor

Claims (7)

A wheel speed sensor for detecting the wheel rotation speed of the vehicle;
A vehicle speed sensor for detecting the traveling speed of the vehicle from the rotational speed of the drive shaft of the vehicle;
Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the wheel speed sensor and information obtained from the vehicle speed sensor;
Vehicle behavior control means for controlling the behavior of the vehicle by individually controlling the rotational speed or driving force of the wheels;
The failure determination means includes
The wheel speed sensor is normal, the absolute value of the difference between the vehicle speed calculated based on information from the wheel speed sensor and the vehicle speed obtained by the vehicle speed sensor is greater than or equal to a predetermined value, and the vehicle behavior control means is inactive A vehicle speed sensor failure determination device that determines that the vehicle speed sensor has failed when all the conditions are satisfied and when all the conditions are satisfied for a predetermined time. A wheel speed sensor for detecting the wheel rotation speed of the vehicle;
A vehicle speed sensor for detecting the traveling speed of the vehicle from the rotational speed of the drive shaft of the vehicle;
Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the wheel speed sensor and information obtained from the vehicle speed sensor;
Vehicle behavior control means for controlling the behavior of the vehicle by individually controlling the rotational speed or driving force of the wheels;
The failure determination means includes
When the wheel speed sensor is normal, the absolute value of the difference between the vehicle speed calculated based on information from the wheel speed sensor and the vehicle speed obtained by the vehicle speed sensor is greater than or equal to a first predetermined value, and the absolute value of the acceleration of the vehicle Is equal to or less than a second predetermined value, and all the conditions that the vehicle behavior control means is inactive are satisfied, and if the satisfaction of all the conditions continues for a predetermined time, it is determined that the vehicle speed sensor has failed. , A failure determination device for a vehicle speed sensor. Wheel speed sensors for detecting the rotational speeds of the left and right wheels of the vehicle,
A vehicle speed sensor for detecting the traveling speed of the vehicle from the rotational speed of the drive shaft of the vehicle;
Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the wheel speed sensor and information obtained from the vehicle speed sensor;
Vehicle behavior control means for controlling the behavior of the vehicle by individually controlling the rotational speed or driving force of the wheels;
The failure determination means includes
The wheel speed sensor is normal, the absolute value of the difference between the vehicle speed calculated based on information from each wheel speed sensor and the vehicle speed obtained by the vehicle speed sensor is equal to or greater than a first predetermined value, and the absolute acceleration of the vehicle All the conditions that the value is equal to or smaller than the second predetermined value, the absolute value of the difference between the vehicle speeds of the left and right wheels obtained from the left and right wheel speed sensors is equal to or smaller than the third predetermined value, and the vehicle behavior control means is inactive are all satisfied. In addition, the vehicle speed sensor failure determination device is characterized in that the vehicle speed sensor is determined to be failed when all the conditions are satisfied for a predetermined time. Wheel speed sensors for detecting the rotational speeds of the left and right wheels of the vehicle,
A vehicle speed sensor for detecting the traveling speed of the vehicle from the rotational speed of the drive shaft of the vehicle;
Failure determination means for determining failure of the vehicle speed sensor based on information obtained from the wheel speed sensor and information obtained from the vehicle speed sensor;
Vehicle behavior control means for controlling the behavior of the vehicle by individually controlling the rotational speed or driving force of the wheels;
The failure determination means includes
The wheel speed sensor is normal, the absolute value of the difference between the vehicle speed calculated based on information from each wheel speed sensor and the vehicle speed obtained by the vehicle speed sensor is equal to or greater than a first predetermined value, and the absolute acceleration of the vehicle The value is equal to or smaller than a second predetermined value, and the absolute value of the difference between the vehicle speeds of the left and right wheels obtained from the left and right wheel speed sensors is equal to or smaller than the third predetermined value. When all the conditions that the average value of the vehicle is equal to or greater than the fourth predetermined value and the vehicle behavior control means are not operating are satisfied and all the conditions are satisfied for a predetermined time, it is determined that the vehicle speed sensor has failed. A vehicle speed sensor failure determination device. 5. The vehicle speed sensor failure determination device according to claim 1, wherein the wheel speed sensor detects a rotation speed of a driving wheel of the vehicle. 6. The vehicle speed sensor failure determination device according to claim 2, wherein the acceleration is a differential value of the vehicle speed calculated based on information from the wheel speed sensor. A failure of the vehicle speed sensor is determined based on information from a wheel speed sensor that detects the wheel rotation speed of the vehicle and information from a vehicle speed sensor that detects the traveling speed of the vehicle from the rotation speed of the drive shaft of the vehicle. A determination method comprising:
Vehicle behavior control for controlling the behavior of the vehicle when the wheel speed sensor is normal and the absolute value of the difference between the vehicle speed calculated based on information from the wheel speed sensor and the vehicle speed obtained by the vehicle speed sensor is equal to or greater than a predetermined value A vehicle speed sensor failure determination method comprising: determining that the vehicle speed sensor is in failure when all the conditions that the means are inactive are satisfied and all conditions are satisfied for a predetermined time.

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