JP2006300783A - Vehicle speed detector, vehicle speed detecting method, and method of determining trouble in vehicle speed sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle speed detector and a vehicle speed detecting method capable of calculating an exact vehicle speed value, even when a plurality of vehicle speed sensors is troubled. <P>SOLUTION: This vehicle speed detector 1 has the plurality of vehicle speed sensors (SP1 sensor, SP2 sensor), and an ECU 2 for determining a trouble in every of the vehicle speed sensors, based on data from the vehicle speed sensors. The ECU 2 stores, as a normal vehicle speed pulse interval, an interval between a reference pulse detection point in the vehicle speed sensor, and a pulse detection point detected before the reference pulse detection point. A predicted time until a pulse is detected after detecting the reference pulse detection point is calculated based on the normal vehicle speed pulse interval, and the vehicle sensor is determined as troubled one when the pulse is not detected within the predicted time. The vehicle speed value after the determination of the trouble is interpolated with the vehicle speed value calculated based on the normal vehicle speed pulse interval. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle speed detection device, a vehicle speed detection method, and a vehicle speed sensor failure determination method including a plurality of, for example, dual vehicle speed sensors including two vehicle speed sensors.

  In recent years, in the control of a vehicle such as an automobile, a vehicle speed value is calculated by a vehicle speed sensor, and the detected vehicle speed value is reflected in various controls such as a transmission control and an engine control. Some vehicle speed detection devices that calculate such vehicle speed values include two vehicle speed sensors SP1 and SP2 sensors that are installed at different locations. In such a vehicle speed detection device, normality and abnormality of the vehicle speed sensor may be determined by the following method.

  First, abnormality determination of the SP1 sensor was performed by determining whether there was a pulse input from the SP1 sensor when the pulse input from the SP2 sensor was received, and no pulse was detected from the SP1 sensor. Sometimes the SP1 sensor is abnormal.

  On the other hand, the abnormality determination of the SP2 sensor was made by determining whether or not there was a pulse input from the SP2 sensor when the pulse input from the SP1 sensor was received, and the pulse from the SP2 sensor was not detected. Sometimes the SP2 sensor is abnormal.

  That is, when there is a pulse input in one sensor, it is determined whether or not the other pulse input is present, and the occurrence of sensor abnormality is mutually monitored.

Although not limited to the vehicle speed detection device, a dual system sensor is used, and if one sensor fails due to disconnection or the like, the other sensor output is used or corrected based on the difference between the two outputs. The value that has been used is being used. Such a control device is disclosed in Patent Document 1 and Patent Document 2, for example.
JP 7-269409 A JP-A-11-36894

  However, as described above, when there is a pulse input in one sensor, it is determined whether or not the other pulse input is present, and if both are configured to monitor the occurrence of sensor abnormality, When the vehicle speed sensor breaks down, an appropriate vehicle speed value cannot be calculated, and thereafter, various controls performed based on the vehicle speed value from the vehicle speed detection device will be affected.

  Therefore, an object of the present invention is to provide a vehicle speed detection device and a vehicle speed detection method capable of calculating an appropriate vehicle speed value even when a plurality of vehicle speed sensors have failed.

  In order to solve such a problem, the vehicle speed detection device of the present invention performs failure determination for each vehicle speed sensor included in the plurality of vehicle speed sensors based on a plurality of vehicle speed sensors and data from the plurality of vehicle speed sensors. An arithmetic unit, such as an ECU, has an interval between a reference pulse detection point in one vehicle speed sensor included in the plurality of vehicle speed sensors and a pulse detection point detected before the reference pulse detection point. Is stored as a normal vehicle speed pulse interval, and a predicted time until pulse detection is performed after the reference pulse detection point is calculated based on the normal vehicle speed pulse interval. A failure of the vehicle speed sensor is determined, and the subsequent vehicle speed value is complemented with another vehicle speed value (claim 1).

  Here, the plurality of vehicle speed sensors are mainly two vehicle speed sensors, but may be more vehicle speed sensors. The determination of the failure of the vehicle speed sensor in the present invention is performed for each vehicle speed sensor, and the plurality of vehicle speed sensors do not depend on each other for the determination of the failure.

  As described above, when a failure is determined for each vehicle speed sensor, a pulse detected before the reference pulse detection point as described above, for example, a pulse detection point (rising edge before the reference pulse detection point). The interval (time) from the time point or the time point of falling) to the reference pulse detection point is measured, and this interval is stored as a normal vehicle speed pulse interval. Based on the normal vehicle speed pulse interval, a pulse detection after the reference pulse detection point, for example, a predicted time to a pulse detection point that will be observed next to the reference pulse detection point is calculated. If a pulse is not detected within this predicted time, if a pulse is detected outside the predicted time, or if multiple pulses are detected within the predicted time, the vehicle speed sensor will fail. It can be set as the structure which determines with having carried out. That is, in the above-described aspect of “determining failure of the one vehicle speed sensor based on the predicted time and the pulse detection status”, pulse detection that is not originally assumed due to the relationship between the predicted time calculated as described above and pulse detection. Various embodiments are included.

  As a result of performing such a failure determination for each vehicle speed sensor, when there is a vehicle speed sensor that does not malfunction, the vehicle speed value can be calculated based on data from the vehicle speed sensor that does not malfunction, When it is determined that all the vehicle speed sensors are out of order, an appropriate vehicle speed value cannot be calculated. Therefore, when it is determined that all the vehicle speed sensors have failed, the vehicle speed value can be calculated based on the normal vehicle speed pulse interval used for the determination of the failure (claim 2). In this way, even when all the vehicle speed sensors are out of order, the vehicle speed value can be tentatively calculated, and the vehicle speed value can be provided to other control systems such as control in the transmission. it can. Here, the normal vehicle speed pulse interval is calculated for each vehicle speed sensor, but it is desirable to adopt the normal vehicle speed pulse interval in the vehicle speed sensor calculated most recently. This is because this is estimated to be close to the actual vehicle speed immediately after the sensor failure.

  However, the normal vehicle speed pulse interval adopted at the present time is a provisional value at the time when the failure is determined, and there is a possibility that it may deviate from the actual vehicle speed every moment. Therefore, the calculation unit can be configured to issue a shift command based on the engine speed after adopting a vehicle speed value based on the normal vehicle speed pulse interval, that is, after determining a failure. This is an attempt to estimate the vehicle speed value at that point in time after considering the engine speed after the pulse of the vehicle speed sensor can no longer be detected.

  In addition, since the actual vehicle speed decreases when the brake is applied, after adopting the vehicle speed value based on the normal vehicle speed pulse interval, control is performed to decrease the normal vehicle speed pulse interval based on the brake signal. (Claim 4).

  In addition, even if the vehicle is actually stopped, if the vehicle speed value based on the normal vehicle speed pulse interval is provided, it affects the subsequent appropriate control. When a vehicle stop state is detected after the vehicle speed value based on the above is adopted, the vehicle speed value based on the normal vehicle speed pulse interval can be replaced with 0 km / h (Claim 5). Here, when the calculation unit continuously receives a signal that the engine speed is equal to or less than a predetermined value, a brake on signal, and a signal that the shift position is a parking position or a neutral position, the vehicle It can be set as the structure which determines with the stop state of (Claim 6). In short, the vehicle speed value based on the normal vehicle speed pulse interval is replaced with 0 km / h when it can be predicted from the driver's operation that the vehicle will stop. It should be noted that not only when all these signals are received but also any one of these signals or a combination of several signals may be used as a condition.

  In such a vehicle speed detection device, after adopting a vehicle speed value based on the normal vehicle speed pulse interval, when a pulse is detected from any of the plurality of vehicle speed sensors, a vehicle speed value based on the detected pulse is adopted. (Claim 7). This is because even after a vehicle speed sensor failure is determined, if the cause of the determination is temporary noise such as noise in the vehicle speed sensor, then the vehicle speed sensor The vehicle speed value by the sensor is adopted.

  As described above, in the vehicle speed detection device of the present invention, when the vehicle speed sensor fails, the vehicle speed value is complemented based on the normal vehicle speed pulse interval. This normal vehicle speed pulse interval is also used to determine the failure of the vehicle speed sensor. That is, the predicted time until the pulse detection after the reference pulse is performed is calculated based on the normal vehicle speed pulse interval in the failure determination process by the calculation unit. Here, it is effective to determine the predicted time according to the state of the vehicle. Accordingly, such a predicted time can be determined as a value that takes into account a constant α that is determined in advance with reference to the normal vehicle speed pulse interval (claim 8). Here, the constant α can be determined from the vehicle weight of the vehicle on which the vehicle speed detection device is mounted, the displacement, and the like. If the normal vehicle speed pulse interval is X, a time ± X (X ± α) with respect to this X Can be used as the predicted time. When the pulse is not detected within the predicted time, it can be determined that the vehicle speed sensor has failed.

  Further, such a determination of the predicted time may be determined as a value obtained by adding a variable α determined based on the vehicle state at the time point to the normal vehicle speed pulse interval. Based on the vehicle state, that is, the throttle opening degree of the vehicle equipped with the vehicle speed detection device, the acceleration, etc., the appropriate value of the variable α can be calculated from time to time, where X is the normal vehicle speed pulse interval. The time (±± α) that is ± α with respect to can be set as the predicted time. If no pulse is detected within the predicted time, it can be determined that the vehicle speed sensor is malfunctioning.

  Thus, in the vehicle speed detection device of the present invention, the normal vehicle speed pulse interval is stored, and the predicted time until pulse detection after the reference pulse is calculated based on the normal vehicle speed pulse interval is calculated. The predicted time may be determined based on the vehicle state at the time, for example, the throttle opening degree, the acceleration, or the like (claim 10). In this case, the predicted time is calculated based on the throttle opening and the acceleration of the vehicle at that time without using the value of the normal vehicle speed pulse interval.

  The arithmetic unit according to the present invention can calculate the predicted time as described above, but the predicted time calculated in this way can be changed according to the road surface condition. For example, when the vehicle wheel slips due to the road surface condition or the wheel grip recovers suddenly, the prediction time can be changed according to such road surface condition. .

  In the vehicle speed detection device of the present invention, the failure of each vehicle speed sensor is determined as described above. However, depending on the situation of the vehicle, the vehicle speed sensor picks up noise or the like, and appropriate pulse detection is not performed. Is also possible (false detection). In such a case, if it is immediately determined that a failure has occurred, smooth control may be hindered, such as hunting. Therefore, the calculation unit that performs the failure determination for each of the plurality of vehicle speed sensors can be configured to determine that the vehicle speed sensor has failed only when the pulse non-detection within the predicted time is performed a plurality of times. . In addition, for the same purpose, the calculation unit that performs failure determination for each of a plurality of vehicle speed sensors is the first time that a vehicle speed sensor has failed unless a pulse is detected within a certain time after the first predicted time has elapsed. It can also be set as the structure to determine (Claim 13).

  In the vehicle speed detection device as described above, when the vehicle is stopped and no pulse is detected from the vehicle speed sensor, the failure determination itself cannot be performed properly. Therefore, the calculation unit of the vehicle speed detection device of the present invention can be configured to perform failure determination of the vehicle speed sensor when the vehicle is at a certain speed or higher (claim 14).

  Next, a vehicle speed detection method according to the present invention is a vehicle speed detection method using a plurality of vehicle speed sensors, and for each vehicle speed sensor, a pulse interval detected before the reference pulse is stored as a normal vehicle speed pulse interval. And calculating a predicted time until pulse detection after the reference pulse is performed based on the normal vehicle speed pulse interval, and determining a failure of the one vehicle speed sensor based on the predicted time and the pulse detection status. When it is determined that the vehicle speed sensor is out of order, a vehicle speed value based on the normal vehicle speed pulse interval is adopted (claim 15).

  Another vehicle speed detection method is a vehicle speed detection method using a plurality of vehicle speed sensors, comparing a vehicle speed value acquired by one vehicle speed sensor with a vehicle speed value acquired by another vehicle speed sensor, For each vehicle speed sensor, the interval between the pulse detection points detected before the reference pulse detection point is stored as a normal vehicle speed pulse interval, and after the reference pulse detection point based on the normal vehicle speed pulse interval. The predicted time until the pulse detection is performed is calculated and a failure of the vehicle speed sensor is determined based on the predicted time and the pulse detection status. If any vehicle speed sensor is determined to be defective, it is determined to be normal. The vehicle speed value acquired by the vehicle speed sensor is adopted (claim 16). When a vehicle speed is detected by using a plurality of vehicle speed sensors, for example, two vehicle speed sensors, the vehicle speed values may be different. In such a case, the vehicle speed value acquired by at least one of the vehicle speed sensors is not a correct vehicle speed value. In such a case, the correct vehicle speed value can be provided by determining the failure using the normal vehicle speed pulse interval and adopting the vehicle speed value obtained by the vehicle speed sensor determined not to be in failure.

  Still another vehicle speed detection method is a vehicle speed detection method using a plurality of vehicle speed sensors, where the vehicle speed value acquired by one vehicle speed sensor is compared with the vehicle speed value acquired by another vehicle speed sensor, and both vehicle speed values are When the values are different, for each vehicle speed sensor, the interval between the pulse detection points detected before the reference pulse detection point is stored as a normal vehicle speed pulse interval, and after the reference pulse detection point based on the normal vehicle speed pulse interval. Calculate a predicted time until pulse detection is performed, determine failure of the vehicle speed sensor based on the predicted time and the pulse detection status, and when all vehicle speed sensors are determined to be failed, the normal vehicle speed pulse interval is set. The vehicle speed value based on this is adopted (claim 17). Similar to the above case, when the vehicle speed is detected by using a plurality of vehicle speed sensors, for example, two vehicle speed sensors, the vehicle speed values may be different. The vehicle speed sensor may be determined to be malfunctioning. In such a case, it is considered that the vehicle speed value from any of the vehicle speed sensors is not a correct vehicle speed value, so that the vehicle speed value based on the normal vehicle speed pulse interval is to be supplemented.

  Next, a vehicle speed sensor failure determination method according to the present invention is a vehicle speed sensor failure determination method, in which an interval between pulse detection points detected before a reference pulse detection point is stored as a normal vehicle speed pulse interval, and the normal vehicle speed A prediction time until pulse detection is performed after the reference pulse detection point is calculated based on a pulse interval, and a failure of the vehicle speed sensor is determined based on the prediction time and a pulse detection status. 16).

  The above vehicle speed detection method and vehicle speed sensor failure determination method can also be implemented by using the vehicle speed detection device of the present invention. When judging the failure of a vehicle speed sensor, if no pulse is detected within the predicted time, if a pulse is detected outside the predicted time, or if multiple pulses are detected within the predicted time, etc. In addition, it is possible to adopt a configuration for determining that the vehicle speed sensor is out of order as in the case of the vehicle speed detection device of the present invention.

  According to the present invention, the calculation unit stores, as a normal vehicle speed pulse interval, a pulse interval detected before a reference pulse in one vehicle speed sensor included in the plurality of vehicle speed sensors, and based on the normal vehicle speed pulse interval, Since the estimated time until the pulse detection after the reference pulse is performed is calculated and the pulse is not detected within the estimated time, it is determined that the failure of the one vehicle speed sensor. It is possible to determine the failure of the vehicle, and the subsequent vehicle speed value can be supplemented with another vehicle speed value. Even when it is determined that all the vehicle speed sensors are out of order, the vehicle speed value can be calculated using the normal vehicle speed pulse interval. Thus, even when it is determined that the vehicle speed sensor has failed, the vehicle speed value can be calculated and reflected in the control of the transmission or the like.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  The vehicle speed detection device 1 of the present invention includes two vehicle speed sensors, an SP1 sensor and an SP2 sensor, and an ECU 2 corresponding to the calculation unit in the present invention connected to these vehicle speed sensors. The SP1 sensor acquires a pulse from the ABS 3 installed in the vicinity of the wheel, and the SP2 sensor is installed so as to acquire a pulse from the output shaft 4. The SP1 sensor is connected to the speedometer 5.

  In such a vehicle speed detection device 1, the ECU 2 separately determines the failure of the SP1 sensor and the SP2 sensor. Such a failure determination method will be described with reference to FIG. Since there is no difference between the SP1 sensor and the SP2 sensor in determining the failure, the determination of the failure in the SP1 sensor will be described.

  First, the ECU 2 detects a pulse input at the points (a), (b), (f), etc. in FIG. That is, these points correspond to pulse detection points. The “reference pulse detection point” in the present invention changes from moment to moment, but here, the description starts from the time point (b) corresponds to the reference pulse detection point.

  The ECU 2 stores the interval between the reference pulse detection point (b) and the previously detected point (a) as the “normal vehicle speed pulse interval”. This “normal vehicle speed pulse interval” is represented by X in FIG.

  The ECU 2 storing the normal vehicle speed pulse interval X then calculates the time when the next pulse is detected after the point (b) based on the normal vehicle speed pulse interval X, that is, the “predicted time” in the present invention. To do. The “predicted time” in the present embodiment is calculated by taking into account the value α calculated by the ECU 2 based on the throttle opening and acceleration of the vehicle. Specifically, the time when the normal vehicle speed pulse interval X has passed from the point (b) to the time point ± α with respect to the point (c), that is, from the point (d) to the point (e) in FIG. The interval is calculated as “predicted time”.

  In the example shown in FIG. 2, since the detection point next to the reference pulse detection point (b), that is, the point (f) is detected within this predicted time, the PS1 sensor has failed at this point. It is determined that there is not.

  After the point (f) is detected in this way, the point (f) becomes the reference pulse detection point at this point. Thereafter, pulses are detected in the same order. That is, the interval from the point (b) to the point (f) becomes the new normal vehicle speed pulse interval X1, and a new predicted time is calculated based on the normal vehicle speed pulse interval X1. In the example shown in FIG. 2, the time when the normal vehicle speed pulse interval X1 has passed from the point (f) is set to ± α1 with respect to the point (g), that is, from the point (h) in FIG. The time between the points is calculated as the “predicted time” at this point.

  Here, if the pulse detection point (j) is detected within the predicted time, it is determined that the SP1 sensor is not broken at this point, but the pulse detection point (j) is detected as shown in FIG. If not, the ECU 2 determines that the SP1 sensor has failed. The basic vehicle speed sensor failure determination method in the vehicle speed detection device 1 has been described above.

  In the failure determination described with reference to FIG. 2 as described above, the ECU 2 determines that there is a failure when there is one pulse not detected within the predicted time, but erroneous detection due to picking up noise or the like. In order to avoid this, control as shown in the flowchart of FIG. 3 can be performed. This process is executed by the ECU 2, the engine of the vehicle on which the vehicle speed detection device 1 is mounted, and is repeatedly executed during the operation of the vehicle speed detection device 1. In such processing, first, it is determined whether or not a sensor failure has been determined (step S11), and if a speed sensor abnormality is detected once (when no pulse is detected within the predicted time), the process proceeds to step S12. move on. In step S12, it is determined whether or not an abnormality has been detected a predetermined number of times N times. When N abnormalities are detected in step S12, the process proceeds to step S13, and it is finally determined that the speed sensor has failed. In cases other than these, that is, if NO is determined in step S11, or if NO is determined in step S12, the process proceeds to step S14 to determine that the speed sensor is normal.

  Further, in order to determine the final speed sensor failure, control based on the flowchart shown in FIG. 4 can be performed instead of the control based on the flowchart shown in FIG. This process is also executed by the ECU 2, the engine of the vehicle on which the vehicle speed detection device 1 is mounted is started, and is repeatedly executed during the operation of the vehicle speed detection device 1. This control will be described. First, in step S21, it is determined whether or not there is a sensor failure determination. When an abnormality of the speed sensor is detected once (when no pulse is detected within the predicted time), the process proceeds to step S22. In step S22, it is monitored whether or not a pulse is detected after the failure determination in step S21. If no pulse is detected, the process proceeds to step S23, and S1 seconds after the first failure determination, that is, the failure determination in step S21. Judgment whether or not has passed. If no pulse is detected during this S1 second, it is finally determined that the sensor has failed. In other cases, that is, when NO is determined in step S21 and step S22, the process proceeds to step S25 and it is determined that the speed sensor is normal.

  The vehicle speed detection device 1 can perform various controls based on such a failure determination method. Hereinafter, each control will be described with reference to the flowcharts shown in FIGS.

  FIG. 5 shows a control flow for complementing the speed value when either or both of the SP1 sensor and the SP2 sensor are determined to be faulty. This process is also executed by the ECU 2, the engine of the vehicle on which the vehicle speed detection device 1 is mounted is started, and is repeatedly executed during the operation of the vehicle speed detection device 1. In such processing, first, in step S31, it is determined whether the SP2 sensor is normal or faulty. If YES is determined, that is, if it is determined that the SP2 sensor is normal, the process proceeds to step S32 and the pulse from the SP2 sensor is detected. Use the calculated speed value. On the other hand, when it is determined NO in step S31, that is, when it is determined that the SP2 sensor is out of order, the process proceeds to step S33. In step S33, it is determined whether the SP1 sensor is normal or malfunctioning. When YES is determined in step S33, that is, when it is determined that the SP1 sensor is normal, the speed value calculated from the pulse by SP1 is adopted (step S34). As a result, the speed value of the faulty SP2 sensor can be repaired and supplemented with the speed value of the SP1 sensor. If NO is determined in step S33, that is, if it is determined that the SP1 sensor is also broken, the process proceeds to step S35. When the process proceeds to step S35, since both the SP1 sensor and the SP2 sensor are in failure, the speed value cannot be calculated from these pulses. Accordingly, in step S35, the speed value is calculated using the normal vehicle speed pulse interval used in the SP2 sensor failure determination in step S31 and the normal vehicle speed pulse interval used in the SP1 sensor failure determination in step S33. At this time, it is desirable to use the normal vehicle speed pulse interval in the SP1 sensor from the viewpoint of obtaining the latest data.

  Further, when it is determined that both the SP1 sensor and the SP2 sensor are out of order, control based on the flowchart shown in FIG. 6 can be performed. This process is also executed by the ECU 2, the engine of the vehicle on which the vehicle speed detection device 1 is mounted is started, and is repeatedly executed during the operation of the vehicle speed detection device 1. First, if it is determined in step S41 that both the SP1 sensor and the SP2 sensor have failed, the process proceeds to step S42. In step S42, as shown in step S35 in the flowchart shown in FIG. 5, repair and complementation are performed based on the speed value using the normal vehicle speed pulse interval. However, this normal vehicle speed pulse interval is at that time, and may deviate from the actual vehicle speed value as time elapses. Therefore, in step S43, it is determined whether or not S2 seconds have elapsed since the failure of both the SP1 sensor and the SP2 sensor has been detected. If it is determined YES in step S43, the ECU 2 proceeds to step S44, stops the vehicle speed calculation by the vehicle speed sensor, and switches to vehicle speed calculation based on the engine speed.

  Further, the vehicle speed detection device 1 can complement the speed value by control based on the flowchart shown in FIG. This process is also executed by the ECU 2, the engine of the vehicle on which the vehicle speed detection device 1 is mounted is started, and is repeatedly executed during the operation of the vehicle speed detection device 1. In such a process, first, in step S51, whether or not fail safe is performed based on the normal vehicle speed pulse interval, that is, both the SP1 sensor and the SP2 sensor have failed, and the speed value is repaired based on the normal vehicle speed pulse interval. , It is determined whether or not the complement is performed. When YES is determined in the step S51, the process proceeds to a step S52 to determine whether or not there is a vehicle stop determination. Here, whether or not the vehicle is stopped is determined by continuously receiving a signal that the engine speed is below a predetermined value, a brake on signal, and a signal that the shift position is the parking position or the neutral position for a certain period of time. Judgment by When such a condition is satisfied, it can be determined that the vehicle is in a stopped state, and thus the process proceeds to step S53 where the vehicle speed value is replaced with 0 km / h. In other cases, that is, when NO is determined in step S51, or when NO is determined in step S52, the control is continued as it is. However, control based on the flowchart shown in FIG. 6 can be performed.

  The control according to the flowchart shown in FIG. 7 is control when it is determined that the vehicle has completely stopped, but the vehicle is braked and it is estimated that the vehicle speed value is gradually decreasing. The control based on the flowchart shown in FIG. 8 can be performed. The processing based on the flowchart shown in FIG. 8 is executed by the ECU 2, the vehicle engine equipped with the vehicle speed detection device 1 is running, and is repeatedly executed during operation of the vehicle speed detection device 1. In such processing, first, in step S61, whether or not fail safe is being performed based on the normal vehicle speed pulse interval, that is, both the SP1 sensor and the SP2 sensor have failed, and the speed value is repaired based on the normal vehicle speed pulse interval. , It is determined whether or not the complement is performed. If YES is determined in the step S61, the process proceeds to a step S62 so as to determine whether or not the brake is on. When YES is determined in the step S62, that is, when the brake is in an ON state, the process proceeds to a step S63 so as to gradually decelerate from the vehicle speed value based on the normal vehicle speed pulse interval. At this time, it is possible to perform control in consideration of how to depress the brake, such as the strength of depressing the brake. In other cases, that is, when NO is determined in step S61, or when NO is determined in step S62, the control is continued as it is. However, control based on the flowchart shown in FIG. 6 can be performed.

  As described above, the vehicle speed detection device 1 can repair and supplement with an appropriate speed value even when both the SP1 sensor and the SP2 sensor are out of order, but for some reason the SP1 sensor and the SP2 sensor are out of order. It is assumed that a normal pulse is detected again after a failure has been detected, such as a temporary one. Therefore, control as shown in FIG. 9 can be performed. This process is also executed by the ECU 2, and the engine of the vehicle on which the vehicle speed detection device 1 is mounted is started, and is repeatedly executed during the operation of the vehicle speed detection device 1. In such a process, first, the ECU 2 performs step S71. In step S72, it is determined whether or not fail safe is being performed based on the normal vehicle speed pulse interval. If it is determined that the vehicle speed is maintained in fail safe, the process proceeds to step S72. In step S72, it is determined whether or not a pulse from at least one of the SP1 sensor and the SP2 sensor is not detected, that is, whether or not the vehicle speed sensor is normal. If YES is determined in step S72, that is, if a pulse is detected, the process proceeds to step S73 to switch to vehicle speed detection in which fail-safe control is performed with reference to the pulse of the vehicle speed sensor. In other cases, that is, when NO is determined in step S71, when NO is determined in step S72, the control is continued as it is.

  The vehicle speed sensor, the SP1 sensor, and the SP2 sensor that constitute the vehicle speed detection device 1 detect pulses at the rotating portions of the wheels and the output shaft. However, when the vehicle speed decreases and the vehicle approaches a stop state, accurate vehicle speed detection is performed. It will be difficult. Therefore, control based on the flowchart shown in FIG. 10 can be performed. This process is also executed by the ECU 2, the engine of the vehicle on which the vehicle speed detection device 1 is mounted is started, and is repeatedly executed during the operation of the vehicle speed detection device 1. In such processing, first, in step S81, it is determined whether or not all the vehicle speed sensors, that is, the SP1 sensor and the SP2 sensor are out of order. If YES, the process proceeds to step S82. In step S82, it is determined whether or not the vehicle speed is a certain value or more. If the vehicle speed is lower than a certain value, the process proceeds to step S83, and the vehicle speed sensor failure detection in the vehicle speed detection device 1 is stopped. In other cases, that is, when NO is determined in step S81, or when NO is determined in step S82, the control is continued as it is.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to them. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

  For example, in the above embodiment, the vehicle speed value acquired by the SP1 sensor and the vehicle speed value acquired by the SP2 sensor are not compared, but when both vehicle speed values are compared and the values are different (the difference between the values is It is also possible to determine whether or not the vehicle speed sensor has failed using the normal vehicle speed pulse interval, and to calculate and complement the vehicle speed value using the normal vehicle speed pulse interval.

It is a block diagram which shows schematic structure of the vehicle speed detection apparatus of an Example. It is explanatory drawing explaining the failure determination method of the vehicle speed sensor in an Example. It is a flowchart which shows an example of failure determination control of a vehicle speed sensor. Similarly, it is a flowchart which shows an example of failure determination control of a vehicle speed sensor. It is a flowchart which shows an example of repair of vehicle speed value, and complementary control. Similarly, it is a flowchart which shows an example of repair of vehicle speed value, and complementary control. It is a flowchart which shows an example of repair of vehicle speed value when it is judged that a vehicle is in a stop state, and complementary control. It is a flowchart which shows an example of repair of vehicle speed value when a brake is applied to a vehicle, and complementary control. It is a flowchart which shows an example of the vehicle speed detection return control by a vehicle speed sensor. It is a flowchart which shows an example of failure determination execution condition discrimination control of a vehicle speed sensor.

Explanation of symbols

1 Vehicle speed detection device 2 ECU
3 ABS
4 Output shaft 5 Speedometer

Claims (18)

Multiple vehicle speed sensors;
A calculation unit that performs failure determination for each vehicle speed sensor included in the plurality of vehicle speed sensors based on data from the plurality of vehicle speed sensors,
The calculation unit stores an interval between a reference pulse detection point in one vehicle speed sensor included in the plurality of vehicle speed sensors and a pulse detection point detected before the reference pulse detection point as a normal vehicle speed pulse interval, Calculate a predicted time until pulse detection is performed after the reference pulse detection point based on a normal vehicle speed pulse interval, determine a failure of the one vehicle speed sensor based on the predicted time and the pulse detection status, and thereafter A vehicle speed detection device supplementing the vehicle speed value of the vehicle with another vehicle speed value. The vehicle speed detection device according to claim 1,
The said calculating part employ | adopts the vehicle speed value based on the said normal vehicle speed pulse interval, when it determines with it being a failure about all of these vehicle speed sensors, The vehicle speed detection apparatus characterized by the above-mentioned. The vehicle speed detection device according to claim 2,
The said calculating part is a vehicle speed detection apparatus which issues a gear shift command based on an engine speed, after employ | adopting the vehicle speed value based on the said normal vehicle speed pulse space | interval. In the vehicle speed detection device according to claim 2 or 3,
The said calculating part reduces the said normal vehicle speed pulse interval based on a brake signal, after employ | adopting the vehicle speed value based on the said normal vehicle speed pulse interval. The vehicle speed detection device according to any one of claims 2 to 4,
The calculation unit replaces the vehicle speed value based on the normal vehicle speed pulse interval with 0 km / h when detecting a stop state of the vehicle after adopting the vehicle speed value based on the normal vehicle speed pulse interval. Detection device. The vehicle speed detection device according to claim 5,
The arithmetic unit stops the vehicle when a signal indicating that the engine speed is below a predetermined value, a brake on signal, or a signal indicating that the shift position is a parking position or a neutral position is continuously received for a certain period of time. A vehicle speed detection device characterized by determining a state. The vehicle speed detection device according to any one of claims 2 to 6,
After adopting a vehicle speed value based on the normal vehicle speed pulse interval, when a pulse is detected from any of the plurality of vehicle speed sensors, a vehicle speed value based on the detected pulse is adopted. . The vehicle speed detection device according to any one of claims 1 to 7,
The said calculating part determines the said prediction time as a value which considered the constant (alpha) previously determined on the basis of the said normal vehicle speed pulse space | interval, The vehicle speed detection apparatus characterized by the above-mentioned. The vehicle speed detection device according to any one of claims 1 to 7,
The said calculating part determines the said estimated time as a value which considered the variable (alpha) defined based on the vehicle state in the said time point in the said normal vehicle speed pulse space | interval. The vehicle speed detection device according to any one of claims 1 to 7,
The said calculating part determines the said estimated time based on the vehicle state in the said time point, The vehicle speed detection apparatus characterized by the above-mentioned. The vehicle speed detection device according to any one of claims 8 to 10,
The vehicle speed detection device characterized in that the predicted time is changed according to a road surface condition. The vehicle speed detection device according to any one of claims 1 to 11,
The vehicle speed detection device, wherein the calculation unit that performs failure determination for each of the plurality of vehicle speed sensors determines that a failure of the one vehicle speed sensor occurs when a pulse undetected within the predicted time is performed a plurality of times. . The vehicle speed detection device according to any one of claims 1 to 11,
The calculation unit that performs failure determination for each of the plurality of vehicle speed sensors determines that the failure of the one vehicle speed sensor is not detected when a pulse is not detected within a predetermined time after the first prediction time has elapsed. Vehicle speed detector. The vehicle speed detection device according to any one of claims 1 to 13,
The vehicle speed detection device, wherein the calculation unit performs failure determination of the vehicle speed sensor when the vehicle is at a certain speed or higher. A vehicle speed detection method using a plurality of vehicle speed sensors,
For each vehicle speed sensor, the interval between pulse detection points detected before the reference pulse detection point is stored as a normal vehicle speed pulse interval, and pulse detection is performed after the reference pulse detection point based on the normal vehicle speed pulse interval. A failure time of the one vehicle speed sensor is determined based on the predicted time and the pulse detection status.
A vehicle speed detection method, comprising adopting a vehicle speed value based on the normal vehicle speed pulse interval when all vehicle speed sensors are determined to be faulty. A vehicle speed detection method using a plurality of vehicle speed sensors,
When the vehicle speed value acquired by one vehicle speed sensor is compared with the vehicle speed value acquired by another vehicle speed sensor, and both vehicle speed values are different values,
For each vehicle speed sensor, the interval between pulse detection points detected before the reference pulse detection point is stored as a normal vehicle speed pulse interval, and pulse detection is performed after the reference pulse detection point based on the normal vehicle speed pulse interval. Calculate the predicted time and determine the failure of the vehicle speed sensor based on the predicted time and the pulse detection status,
A vehicle speed detection method comprising adopting a vehicle speed value acquired by a vehicle speed sensor determined to be normal when any of the vehicle speed sensors is determined to be malfunctioning. A vehicle speed detection method using a plurality of vehicle speed sensors,
When the vehicle speed value acquired by one vehicle speed sensor is compared with the vehicle speed value acquired by another vehicle speed sensor, and both vehicle speed values are different values,
For each vehicle speed sensor, the interval between pulse detection points detected before the reference pulse detection point is stored as a normal vehicle speed pulse interval, and pulse detection is performed after the reference pulse detection point based on the normal vehicle speed pulse interval. Calculate the predicted time and determine the failure of the vehicle speed sensor based on the predicted time and the pulse detection status,
A vehicle speed detection method, comprising adopting a vehicle speed value based on the normal vehicle speed pulse interval when all vehicle speed sensors are determined to be faulty. A vehicle speed sensor failure determination method,
An interval between pulse detection points detected before the reference pulse detection point is stored as a normal vehicle speed pulse interval, and an estimated time until pulse detection is performed after the reference pulse detection point is calculated based on the normal vehicle speed pulse interval. And determining a failure of the vehicle speed sensor based on the predicted time and the pulse detection status.

Images