JPH06101561A - Abnormality detection device for vehicle speed detection means - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the time until the abnormality of the vehicle speed detection means is detected. [Structure] An automatic transmission 7 for transmitting the driving force to a drive shaft is drivingly connected to the engine 1. An intake pressure sensor 23, a water temperature sensor 25, a rotation speed sensor 26, a vehicle speed sensor 28, a neutral switch 29, etc. are connected to the ECU 30 of the vehicle. When a predetermined time has elapsed after the shift position is detected to be in the non-neutral state, and the engine speed is equal to or higher than the reference speed, the vehicle speed sensor 28 indicates that the vehicle speed is "0". It is assumed that an abnormality has occurred. Even if the predetermined time has not elapsed, the cooling water temperature is a value indicating the warm-up completion state of the engine 1, and the engine speed and the intake pressure are values indicating that the power transmission of the automatic transmission 7 is possible. When a certain state has passed for a short time, it is considered that a predetermined time has passed. Therefore, when an abnormality occurs in the vehicle speed sensor 28, it is immediately detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting device for vehicle speed detecting means for detecting the speed of a vehicle.
The present invention relates to a device which is provided in a vehicle equipped with an automatic transmission and detects an abnormality due to a disconnection or the like of a vehicle speed detecting means.

[0002]

2. Description of the Related Art Conventionally, a vehicle speed detection signal from a vehicle speed sensor is used as one of important parameters when various engine controls are performed, for example, when an idle state is determined in idle speed control. However, if the signal line for transmitting the vehicle speed signal to the control device is disconnected or the connector part is dropped and the vehicle speed signal is not transmitted to the control device, various control will be hindered. Become.

Therefore, in order to detect the abnormality of the vehicle speed detecting means as described above, various abnormality detecting devices of the vehicle speed detecting means have been conventionally proposed. Examples of this type of technology include those disclosed in Japanese Patent Laid-Open No. 61-21454. In this technology, if the engine speed is above a certain value,
It is determined that the vehicle speed sensor system is abnormal when the detected vehicle speed is zero under the condition that the vehicle is in the traveling state, that is, the shift position of the automatic transmission is not in the neutral state. In this way, when the abnormality of the vehicle speed sensor system is detected, by setting the condition that the shift position of the automatic transmission is not in the neutral state, it is relatively possible that the vehicle is not in the racing state, that is, in the traveling state. It was possible to detect reliably.

[0004]

However, in reality,
It takes a considerable time for the driving force of the engine to be transmitted to the drive shaft through the automatic transmission. In particular,
In the cold state, it takes a very long time until the driving force is completely transmitted. Therefore, in the above-mentioned conventional technique, it is necessary to provide a predetermined guarantee time from when the shift position is detected not in the neutral state (in the non-neutral state) until the driving force of the engine is completely transmitted to the drive shaft. there were. Then, it was not possible to determine that the vehicle was in the running state until the non-neutral state passed the guaranteed time. As a result, if an abnormality actually occurs in the vehicle speed sensor system,
It took a long time to judge the abnormality.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to make it possible to shorten the time until the abnormality is detected when the vehicle speed detecting means has an abnormality. An object of the present invention is to provide an abnormality detection device for a vehicle speed detection means.

[0006]

In order to achieve the above object, according to the present invention, as shown in FIG.
The vehicle speed detection means M4 provided in the vehicle M3 having the automatic transmission M2 connected to the vehicle 1 and detecting the speed of the vehicle M3, and whether the shift position of the automatic transmission M2 is in the non-neutral state or not. Shift position detecting means M5 for detecting
And a rotation speed detection means M for detecting the rotation speed of the internal combustion engine M1.
6, and after the shift position detecting means M5 detects that the shift position is in the non-neutral state, the time measuring means M7 for measuring the duration of the state and the detection result of the time measuring means M7 are the power of the automatic transmission M2. The time is equal to or longer than a predetermined time corresponding to the transferable time, and the detection result of the rotation speed detection means M6 is equal to or larger than a predetermined value corresponding to the travelable rotation speed of the vehicle M3, and An abnormality detecting device for vehicle speed detecting means, comprising: an abnormality determining means M8 for determining that the vehicle speed detecting means M4 is abnormal when the detection result of the vehicle speed detecting means M4 is equal to or less than a predetermined value. The temperature state detecting means M9 for detecting the temperature state of the engine M1, the load state detecting means M10 for detecting the load state of the internal combustion engine M1, and the detection result of the temperature state detecting means M9 are the internal combustion engine. Corresponds to the warmed-up state of M1, the detection result of the rotation speed detection means M6 and load condition detecting means M10
When it is determined that the detection result of No. 1 corresponds to the traveling state of the vehicle M3, the vehicle speed detection is characterized by including a deciding unit M11 that regards the measurement result of the clocking unit M7 as being longer than a predetermined time. The gist is the abnormality detection device of the means.

[0007]

According to the above construction, as shown in FIG. 1, the vehicle speed detecting means M4 detects the speed of the vehicle M3, and the shift position detecting means M5 determines whether the shift position of the automatic transmission M2 is in the non-neutral state. Whether or not it is detected is detected, and the rotation speed detection means M6 detects the rotation speed of the internal combustion engine M1 provided in the vehicle M3. Further, the time measuring means M7 measures the duration of the state after the shift position is detected to be in the non-neutral state. Then, the timing means M7
Is greater than or equal to a predetermined time period, the detection result of the rotation speed detection means M6 is greater than or equal to a predetermined value, and the detection result of the vehicle speed detection means M4 is greater than or equal to a predetermined time. When the value is less than or equal to the value, the abnormality determination means M8 determines that the vehicle speed detection means M4 is abnormal.

The temperature state detecting means M9 detects the temperature state of the internal combustion engine M1, and the load state detecting means M10 detects the load state of the internal combustion engine M1. Then, the detection result of the temperature state detecting means M9 corresponds to the warm-up completion state of the internal combustion engine M1, and the detection result of the rotation speed detecting means M6 and the load state detecting means M10 are the power transmission possible state of the automatic transmission M2. If it is determined that the time is equal to, the deciding means M11 considers that the detection result of the time measuring means M7 is equal to or longer than a predetermined time.

Therefore, even if the duration of the non-neutral state has not exceeded the predetermined time, the engine temperature is a value indicating the warm-up completion state, and the rotation speed and load of the internal combustion engine M1 are the power transmission of the automatic transmission M2. If the value indicates the ready state, it is considered that a predetermined time or more has elapsed. Therefore, even if an abnormality occurs in the vehicle speed detecting means M4, if the deciding means M11 considers that a predetermined time or more has elapsed, the abnormality determining means M8 immediately determines that the vehicle speed detecting means M4 is abnormal. To be done.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the abnormality detecting device for vehicle speed detecting means according to the present invention will be described in detail below with reference to FIGS.

FIG. 2 is a schematic configuration diagram showing an engine system provided with a vehicle speed sensor which is an abnormality detection target of this embodiment. An engine 1 as an internal combustion engine takes in outside air from an air cleaner 3 via an intake passage 2. Further, at the same time when the outside air is taken in, the engine 1 has its intake port 1a.
The fuel injected from the injector 4 provided for each cylinder in the vicinity of is taken in. Then, the mixture of the taken-in fuel and the outside air is introduced into the combustion chamber 1b through the intake valve 5a provided for each cylinder, and an explosion occurs in the combustion chamber 1b.
After being burned to obtain the driving force, the exhaust gas is led out to the outside through the exhaust valve 5b to the exhaust passage 6 where the exhaust manifold for each cylinder gathers, and is exhausted to the outside.

The engine 1 is drivingly connected to an automatic transmission 7 for transmitting its driving force to a drive shaft (not shown). Then, the driving force of the engine 1 is transmitted to the drive shaft via the automatic transmission 7.

A throttle valve 8 which is opened and closed in conjunction with an accelerator pedal (not shown) is provided in the intake passage 2. Then, by opening and closing the throttle valve 8, the amount of intake air into the intake passage 2 is adjusted. A surge tank 9 for smoothing the pulsation of intake air is provided downstream of the throttle valve 8.

An intake air temperature sensor 21 for detecting the intake air temperature is provided near the air cleaner 3 in the intake passage 2. A throttle sensor 22 for detecting the opening of the throttle valve 8, that is, the throttle opening TA is provided near the throttle valve 8. In addition, surge tank 9
An intake pressure sensor 23 is provided as a load state detection unit that communicates with the tank 9 and detects an intake pressure (intake pressure) PiM corresponding to the load of the engine 1.

On the other hand, an oxygen sensor 24 for detecting the oxygen concentration in the exhaust gas is provided in the exhaust passage 6. Further, the temperature of the cooling water (cooling water temperature) T
Water temperature sensor 2 as temperature state detecting means for detecting HW
The ignition signal distributed by the distributor 11 is applied to the spark plug 10 provided for each cylinder of the engine 1 in which the engine 5 is provided. Distributor 11
Is for distributing the high voltage output from the igniter 12 to each spark plug 10 in synchronization with the crank angle of the engine 1. The ignition timing of each spark plug 10 is determined by the high voltage output timing from the igniter 12. To be done.

The distributor 11 has a rotation speed sensor 26 as a rotation speed detecting means for detecting the rotation speed (engine speed) NE of the engine 1 from the rotation of a rotor (not shown) of the distributor 11, and similarly the rotation speed sensor 26 responds to the rotation of the rotor. Cylinder discrimination sensors 27 that detect changes in the crank angle of the engine 1 at a predetermined ratio are attached. In this embodiment, the engine 1 is used for one stroke.
, The cylinder discrimination sensor 27 is 30 °
The crank angle is detected at the rate of CA.

A vehicle speed sensor 28 is provided near the automatic transmission 7 as a vehicle speed detecting means for detecting the speed (vehicle speed) SPD of the vehicle. Further, the automatic transmission 7 is provided with a neutral switch 29 as shift position detecting means for detecting whether or not the shift position is in the neutral state. This neutral switch 29
Outputs a neutral signal NS which is "on" when it is detected that the shift position is in the neutral state and is "off" when it is not detected that the shift position is in the neutral state.

An instrument panel (not shown) inside the vehicle is provided with a sensor abnormality lamp 13 which is flickered to inform the abnormality of the vehicle speed sensor 28.

The sensor abnormality lamp 13 is electrically connected to an electronic control unit (hereinafter simply referred to as "ECU") 30. The ECU 30 constitutes a time measuring means, an abnormality judging means, and a deeming means. This EC
U30 includes an intake air temperature sensor 21 and a throttle sensor 2
2, intake pressure sensor 23, oxygen sensor 24, water temperature sensor 2
5, a rotation speed sensor 26, a cylinder discrimination sensor 27, a vehicle speed sensor 28, and a neutral switch 29 are connected to each other. The ECU 30 executes various calculation and determination processes based on the detection signals from the sensors 21 to 28 and the neutral switch 29. The ECU 30 drives and controls the injector 4 and the igniter 12 based on the calculation and the determination result, and when it determines that the vehicle speed sensor 28 is abnormal, the sensor abnormality lamp 13
Is controlled to blink.

Next, the structure of the ECU 30 will be described with reference to the block diagram of FIG. The ECU 30 includes a central processing unit (CPU) 31, a read-only memory (ROM) 32 that stores a predetermined control program and the like in advance, and a random access memory (RA) that temporarily stores calculation results of the CPU 31 and the like.
M) 33, a backup RAM 34 for storing prestored data, and the like, and a logical operation circuit in which these units are connected to an external input circuit 35, an external output circuit 36, and the like by a bus 37.

The external input circuit 35 includes an intake air temperature sensor 21, a throttle sensor 22, an intake pressure sensor 23,
Oxygen sensor 24, water temperature sensor 25, rotation speed sensor 26,
A cylinder discrimination sensor 27, a vehicle speed sensor 28, a neutral switch 29, etc. are connected to each other. Further, the injector 4, the igniter 12, the sensor abnormality lamp 13 and the like described above are connected to the external output circuit 36, respectively. Then, the CPU 31 reads the detection signals from the sensors 21 to 28 and the neutral switch 29 via the external input circuit 35 as input values. Further, the CPU 31, based on these input values, through the external output circuit 36, the injector 4, the igniter 12, and the sensor abnormality lamp 13.
And the like are controlled appropriately. The CPU 31 has first and second counters 38 and 39 having a counting function built therein.

Next, of the various processing operations executed by the ECU 30 described above, the processing operation for determining an abnormality when an abnormality occurs in the vehicle speed sensor 28 will be described with reference to FIGS.

The flow charts shown in FIGS.
This is an "abnormality determination routine" executed by 0, which is started at the same time as the cranking of the engine 1 is started, and thereafter is executed by a timed interrupt every predetermined time.

When the processing of this routine is started, first, at step 101, the throttle opening TA, the intake pressure PiM, the cooling water temperature THW, the engine speed NE are detected based on the detection results of the sensors 21 to 28 and the neutral switch 29. , Vehicle speed SPD, neutral signal NS, etc. are read as input values.

Next, at step 102, it is judged whether or not the neutral signal NS read this time is "off". Then, the neutral signal NS is “off”.
If not, the subsequent processing is temporarily terminated assuming that the shift position is in the neutral state. If the neutral signal NS is "OFF", it is determined that the shift position is not in the neutral state, and the process proceeds to the next step 103. Then, in step 103, the CPU
The first counter 38 incorporated in 31 starts counting.

Next, at step 104, it is judged if the count value C1 of the first counter 38 has passed a predetermined time "α1". The predetermined time “α1” is approximately equal to a normal guarantee time until the driving force of the engine 1 is completely transmitted to the drive shaft via the automatic transmission 7. And the count value C
When 1 has passed the predetermined time “α1”, the shift position becomes the non-neutral state, and it is assumed that the driving force of the engine 1 is completely transmitted to the drive shaft, and the routine proceeds to step 110 described later. If the count value C1 has not passed the predetermined time “α1”, the process proceeds to step 105.

In step 105, it is determined whether or not the cooling water temperature THW read this time is equal to or higher than a predetermined value "β". Then, when the cooling water temperature THW is not equal to or higher than the predetermined value “β”, it is determined that the warm-up of the engine 1 has not been completed yet, and the subsequent processing is temporarily ended. If the cooling water temperature THW is equal to or higher than the predetermined value "β", it is determined that the warm-up is completed and the following step 10 is performed.
Go to 6.

In step 106, it is determined whether the engine speed NE read this time is within a predetermined range, that is, a predetermined value "γ" or more and a predetermined value "δ" or less. To judge. If the engine speed NE is not within the predetermined range, for example, the engine speed NE is too low, and step 1 described below is performed.
The subsequent processing is temporarily terminated because it is not worth performing the processing of 07. If the engine speed NE is within the predetermined range, the process proceeds to step 107.

In step 107, it is determined whether or not the intake pressure PiM read this time is larger than a predetermined value "ε", under the condition that the engine speed NE is within a predetermined range. To judge. If the intake pressure PiM is not larger than the predetermined value “ε”, the current operating state is automatic even though the throttle valve 8 is opened by the accelerator pedal and the engine speed NE is increased to some extent. It is assumed that the drive force of the engine 1 has not been completely transmitted to the drive shaft by the transmission 7, that is, a so-called racing state, and the subsequent processing is temporarily terminated. If the intake pressure PiM is larger than the predetermined value “ε”, it is determined that the current driving state is not the racing state, that is, the running state, and the process proceeds to step 108.

Now, the processes of steps 106 and 107 will be further described. FIG. 6 is a graph showing the relationship between the engine speed and the intake pressure with respect to time when the driving state is the racing state. Also,
FIG. 7 is a graph showing the relationship between the engine speed and the intake pressure with respect to time when the operating state is the running state.
As is clear from the graph of FIG. 6, generally, in the racing state, the degree of increase of the intake pressure PiM with the increase of the engine speed NE is small. That is, when the engine speed NE is within a predetermined range (“γ” ≦ NE ≦
It can be seen that in “δ”), the intake pressure PiM is always smaller than the predetermined value “ε”. On the other hand, as is clear from the graph of FIG. 7, in the traveling state in which the automatic transmission is engaged in the "first speed", the degree of increase in the intake pressure PiM with the increase in the engine speed NE is large. That is, when the engine speed NE is within the predetermined range (“γ” ≦ N
It can be seen that in E ≦ “δ”), the intake pressure PiM is always in the relation of not less than the predetermined value “ε”.

Therefore, in step 107,
When the intake pressure PiM is larger than the predetermined value “ε”, it is determined that the current driving state is not the racing state, that is, the running state. In this embodiment, the predetermined value “ε” is the maximum value when the vehicle is in the stopped state, all the electric loads such as the air conditioner are in the “ON” state, and the power steering is in the “steady-state” state. Is set to.

Then, in the following step 108,
The second counter 39 incorporated in the CPU 31 starts counting. Next, in step 109, it is determined whether or not the count value C2 of the second counter 39 has passed a predetermined time “α2”. The predetermined time “α2” is a time required to confirm that the data read this time is not instantaneous noise, and is a time much shorter than the predetermined time “α1” described above. Then, when the count value C2 has exceeded the predetermined time “α2”, the count value C1 is determined in step 104 described above.
Although the predetermined time “α1” has not yet passed, it is assumed that the current driving state is the running state and the driving force of the engine 1 is completely transmitted to the drive shaft, and the next step 110 Move to. If the count value C2 has not passed the predetermined time “α2” yet, it is considered that the data read this time may be instantaneous noise, and the subsequent processing is temporarily terminated.

After shifting from step 104 or step 109, in step 110, the reference rotational speed Nθ used in the next step 111 is calculated based on the throttle opening TA read this time. The reference rotation speed Nθ calculated here differs depending on the throttle opening TA at that time, and becomes a high value as the reference rotation speed Nθ increases. The reference rotation speed Nθ is the minimum rotation speed required for the vehicle speed SPD not to become “0” (that is, the reference rotation speed Nθ is based on the stall rotation speed of the engine 1 corresponding to the throttle opening TA). Value).

Next, at step 111, it is judged if the engine speed NE read this time is equal to or higher than the reference speed Nθ calculated at step 110.
When the engine speed NE is not equal to or higher than the reference speed Nθ, a condition for determining whether or not there is an abnormality in the vehicle speed sensor 28, that is, the current driving state is the running state, and the driving force of the engine 1 is the automatic transmission. The subsequent processing is once terminated on the assumption that the condition of being completely transmitted to the drive shaft via 7 is not satisfied. If the engine speed NE is equal to or higher than the reference speed Nθ, it is determined that all the conditions for determining whether or not the vehicle speed sensor 28 is abnormal are satisfied, and the process proceeds to the next step 112.

In step 112, it is determined whether the vehicle speed SPD read this time is "0". When the vehicle speed SPD is not "0", the vehicle speed sensor 2
Assuming that 8 is normal, the subsequent processing is temporarily terminated. Further, when the vehicle speed SPD is “0”, although the current driving state is the running state and the driving force of the engine 1 is completely transmitted to the drive shaft via the automatic transmission 7, Since the detected vehicle speed SPD is "0", it is determined that there is an abnormality in the vehicle speed sensor 28 or its electric circuit system, and the process proceeds to the next step 113.

Then, in step 113, the backup RAM 34 stores a diagnostic code that supports the occurrence of an abnormality in the vehicle speed sensor 28. Then, in step 114, the sensor abnormality lamp 13 is made to blink. Further, in step 115, the count values C1 and C2 of the first and second counters 38 and 39 are reset to "0", and the subsequent processing is temporarily terminated.

As described above, in this embodiment, the count value C1 after the shift position is detected to be in the non-neutral state is the predetermined time "α1" or more,
Further, when the engine speed NE is equal to or higher than the reference speed Nθ according to the throttle opening TA at that time, it is assumed that all the conditions for determining whether or not there is an abnormality in the vehicle speed sensor 28 are satisfied. Then, when the vehicle speed SPD at that time is "0", it is assumed that an abnormality has occurred in the vehicle speed sensor 28. Therefore, even if the vehicle speed sensor 28 is not abnormal, there is no possibility that the vehicle speed sensor 28 is erroneously detected as abnormal. On the contrary, when an abnormality occurs in the vehicle speed sensor 28, it can be reliably detected.

Further, the count value C1 is "α1" for a predetermined time.
Even when the temperature has not passed, the cooling water temperature THW is a value (THW ≧ “β”) indicating the warm-up completion state of the engine 1,
A value indicating that the engine speed NE and the intake pressure PiM are in a power transmittable state of the automatic transmission 7 (“γ” ≦ NE ≦
When the state of “δ”, PiM ≧ “ε”) has passed the predetermined time “α2”, it is considered that the predetermined time “α1” has passed. Moreover, the predetermined time “α2” is considerably shorter than the predetermined time “α1”.
Therefore, when it is considered that the predetermined time “α1” has elapsed, it is immediately determined that the vehicle speed sensor 28 or its electric circuit system is abnormal. As a result, it is possible to shorten the time required to detect an abnormality as a whole.

Further, in this embodiment, the vehicle speed sensor 28
If an abnormality occurs in the backup RAM 34, a diagnostic code that supports the abnormality is stored in the backup RAM 34. That is, the history of such an abnormality is stored in the backup RAM 34. Therefore, such history of abnormality of the vehicle speed sensor 28 can be easily recognized at the time of regular inspection by the dealer.

In addition, in this embodiment, the vehicle speed sensor 28
When an abnormality occurs in the sensor, the sensor abnormality lamp 13 is made to blink. Therefore, the driver can easily and instantly recognize such an abnormality of the vehicle speed sensor 28.

The present invention is not limited to the above-described embodiment, but can be implemented as follows by appropriately modifying a part of the configuration without departing from the spirit of the invention. (1) In the above-described embodiment, the intake pressure sensor 23 is adopted as a means for detecting the load applied to the engine 1, and the sensor 2
Although the intake pressure PiM corresponding to the load is detected at 3, the intake flow rate Q is detected by an air flow meter disposed in the intake passage 2 upstream of the throttle valve 8 instead of the intake pressure PiM. May be the load equivalent value.

(2) In the above embodiment, the sensor abnormality lamp 13 is made to blink when an abnormality occurs in the vehicle speed sensor 28. However, instead of the sensor abnormality lamp 13, an existing lamp (for example, overdrive off) is used. The lamp) may blink. Further, instead of the lamp, a buzzer or the like may be used to notify the driver of the abnormality.

[0043]

As described above in detail, according to the present invention, the detection result of the time measuring means is equal to or longer than a predetermined time, and the detection result of the rotation speed detecting means is a predetermined value. In the above case, when the detection result of the vehicle speed detecting means is less than or equal to a predetermined value, it is determined that the vehicle speed detecting means is abnormal. In such an abnormality detection device, even if the duration of the non-neutral state has not exceeded the predetermined time, the engine temperature is a value indicating the warm-up completion state, and the rotation speed and load of the internal combustion engine are the power of the automatic transmission. If it is a value indicating that transmission is possible, it is considered that a predetermined time or more has elapsed. Therefore, when there is an abnormality in the vehicle speed detecting means, there is an excellent effect that the time until the abnormality is detected can be shortened.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing an engine system including a vehicle speed sensor that is an abnormality detection target in an embodiment embodying the present invention.

FIG. 3 is a block diagram showing a configuration of an ECU in one embodiment.

FIG. 4 is a flowchart showing a process of an “abnormality determination routine” executed by the ECU in the embodiment.

FIG. 5 is a flowchart continued from FIG. 4 showing a process of an “abnormality determination routine” executed by the ECU in the embodiment.

FIG. 6 is a graph showing a relationship between engine speed and intake pressure with respect to time when a driving state is a racing state in one example.

FIG. 7 is a graph showing the relationship between engine speed and intake pressure with respect to time when the operating state is a running state in one example.

[Explanation of symbols]

1 ... Engine as internal combustion engine, 7 ... Automatic transmission, 23
Intake pressure sensor as load state detecting means 25 Water temperature sensor as temperature state detecting means 26 Rotation speed sensor as rotational speed detecting means 28 Vehicle speed sensor as vehicle speed detecting means 29 Shift position detecting means The neutral switch, 30 ... An ECU constituting a time measuring means, an abnormality judging means and a deeming means.

Claims (1)

[Claims] 1. A vehicle speed detecting means provided in a vehicle equipped with an automatic transmission connected to an internal combustion engine, for detecting a speed of the vehicle; and whether or not a shift position of the automatic transmission is in a non-neutral state. Shift position detecting means for detecting whether or not, the rotational speed detecting means for detecting the rotational speed of the internal combustion engine, and after the shift position detecting means detects that the shift position is in the non-neutral state, Time measuring means for measuring the duration, the detection result of the time measuring means is a predetermined predetermined time or more corresponding to the power transmission time of the automatic transmission, and the detection result of the rotation speed detection means When the vehicle speed is equal to or higher than a predetermined value which corresponds to the number of revolutions of the vehicle and the detection result of the vehicle speed detecting means is equal to or lower than a predetermined value, the vehicle In an abnormality detection device for vehicle speed detection means comprising an abnormality determination means for determining that the detection means is abnormal, a temperature state detection means for detecting a temperature state of the internal combustion engine, and a load for detecting a load state of the internal combustion engine State detection means, the detection result of the temperature state detection means corresponds to the warm-up completion state of the internal combustion engine, the detection result of the rotation speed detection means and the detection result of the load state detection means in the running state of the vehicle An abnormality detecting device for vehicle speed detecting means, characterized in that, when it is judged to be equivalent, a deciding means which regards the measurement result of the time measuring means as being longer than a predetermined time is provided.