JPH0736501A - Failure detecting device for on-vehicle sensor - Google Patents

Abstract

PURPOSE:To prevent the misdetection of the failure of an on-vehicle sensor in a large current load driving state set by an on-vehicle controller in regard of a failure detecting device for the on-vehicle sensor that has such a layout where the ground positions are set apart from each other to secure the reference voltage between the voltage sensor and the on-vehicle controller which detects the failure of the sensor. CONSTITUTION:An on-vehicle controller (c) decides the failure of an on-vehicle sensor (a) when the analog signal transmitted from the sensor (a) gets out of a normal deciding range. A sensor failure detecting circuit (f) of the controller (c) is provided with a sensor failure detection inhibiting means (g) to inhibit detection of the failure of the sensor (a) in a large current load driving state set by the controller (c).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle sensor failure detecting device having a layout in which a ground position for taking a reference voltage is separated from an on-vehicle sensor and an on-vehicle controller for detecting a sensor failure.

[0002]

2. Description of the Related Art Conventionally, as a power supply voltage fail detection circuit, for example, as described in Japanese Patent Laid-Open No. 59-213551, a retrigger timer is used to make the power supply voltage level above an upper limit value. A circuit is known that detects that the power supply voltage is abnormal when the voltage is equal to or lower than the lower limit value.

An on-vehicle sensor (for example, a throttle opening sensor, etc.) that outputs an analog signal based on a voltage value is applied to this technique.
If the output voltage level from the in-vehicle sensor is above the upper limit or below the lower limit,
The sensor failure detection circuit detects that the vehicle-mounted sensor is abnormal.

[0004]

However, in the fail detection device for the on-vehicle sensor, the on-vehicle sensor and the controller having the sensor fail detection circuit for detecting the sensor failure are installed at positions separated from each other such as the front of the vehicle and the rear of the vehicle. In this case, the normal vehicle-mounted sensor may be erroneously detected as a failure when the controller drives a large current load.

That is, since the vehicle-mounted sensor and the controller are separated from each other at the ground position for taking the reference voltage, the ground wire of the controller has an apparent resistance when the controller drives a large current load, and this resistance causes the reference voltage to be applied. If the voltage level of (earth voltage) instantaneously rises from the original 0 volt and the reference voltage level rises significantly, it is determined that the output voltage level from the vehicle-mounted sensor is below the lower limit value,
The on-vehicle sensor is erroneously detected as a failure.

In particular, when the vehicle-mounted sensor is a throttle opening sensor arranged in front of the vehicle and the controller is an anti-skid brake controller (hereinafter referred to as ABS controller) arranged in the rear of the vehicle, a plurality of ABS solenoids are operated during ABS operation. The throttle opening sensor is erroneous because the throttle opening sensor outputs a low voltage during ABS operation, which is a low throttle opening. Very likely to be detected.

The present invention has been made in view of the above problems. A first object of the present invention is to provide a layout in which a ground position for taking a reference voltage is separated from a vehicle-mounted sensor and a vehicle-mounted controller for detecting a sensor failure. In a fail detection device for a vehicle-mounted sensor having the above, it is to prevent erroneous detection of a sensor failure when a large-current load is driven by the vehicle-mounted controller.

A second object is to prevent erroneous detection of sensor failure without the need to judge whether or not a large current load is being driven.

[0009]

In order to achieve the above first object, the fail detection device for an on-vehicle sensor according to claim 1 uses a predetermined physical quantity as an analog signal as shown in the claim correspondence diagram of FIG. An in-vehicle sensor a for outputting and an in-vehicle controller c for outputting a driving current to the actuator b when the control condition is satisfied are provided.
The first ground d for taking the reference voltage of the above is separated from the second ground e for taking the reference voltage of the vehicle controller c, and the analog signal output from the vehicle sensor a is output to the vehicle controller c from the normal judgment range. In a fail detection device for an on-vehicle sensor having a sensor fail detection circuit f for detecting that the on-vehicle sensor a has failed when it is disengaged, the sensor fail detection circuit f detects a sensor failure when a large current load is driven by the on-vehicle controller c. Is provided with a sensor failure detection prohibiting means g for prohibiting.

In order to achieve the second object, the fail detecting device for an on-vehicle sensor according to claim 2 is the fail detecting device for an on-vehicle sensor according to claim 1, wherein the on-vehicle controller c includes at least an anti-skid brake controller. It is a controller, and the sensor failure detection inhibiting means g is means for inhibiting the sensor failure detection during the operation of the anti-skid brake.

[0011]

The operation of the present invention will be described.

When the actuator b is not driven by the vehicle controller c or is driven at a low load, the analog signal output from the vehicle sensor a, which outputs a predetermined physical quantity as an analog signal, is within the normal judgment range in the sensor failure detection circuit f. If the in-vehicle sensor a is detected as normal,
When it is out of the normal determination range, the in-vehicle sensor a is detected as a failure.

On the other hand, when the vehicle controller c drives the actuator b under a large current load, the sensor failure detection prohibiting means g prohibits the sensor failure detection circuit f from detecting the sensor failure of the vehicle sensor a.

Therefore, when the in-vehicle controller c drives the actuator b under a large current load, the in-vehicle sensor a
Since the first ground d and the second ground e that take the reference voltage of the on-vehicle controller c are separated from each other, the ground wire of the on-vehicle controller c has an apparent resistance, and this resistance increases the reference voltage, Due to the difference between the reference voltage of the vehicle-mounted sensor a and the normal output from the vehicle-mounted sensor a, the sensor-fail detection circuit f of the vehicle-mounted controller c erroneously detects a sensor failure. Is prevented.

The operation of the invention according to claim 2 will be described.

When the wheels are likely to lock due to braking on a low μ road or during sudden braking, a drive command is output from the anti-skid brake controller, which is the on-vehicle controller c, to the actuator b for the square wheel to suppress the wheel lock. The anti-skid brake is activated. During the operation of the anti-skid brake, the sensor failure detection prohibiting means g prohibits the sensor failure detection without determining whether or not it is driven by a large current load.

Therefore, paying attention to the fact that a plurality of actuators b are often driven simultaneously during the operation of the anti-skid brake, inevitably driving a large current load, and the sensor fail detection prohibition condition is that the anti-skid brake is operating. By the replacement, it is possible to prevent the erroneous detection of the sensor failure without the necessity of determining whether the high current load is being driven.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure will be described.

FIG. 2 is a block diagram showing an on-vehicle electronic control system to which the on-vehicle sensor failure detection device of the embodiment of the present invention is applied.

In FIG. 2, 1 is a throttle opening sensor (corresponding to an on-vehicle sensor a), 2 is an ABS / ETS control unit (corresponding to an on-vehicle controller c), and 3 is AB.
S actuator (corresponding to actuator b), 4 is first ground, 5 is second ground, 6 is battery, 7 is ECC
S control unit, 8 wheel rotation sensor, 9 G
Sensor, 10 is ABS actuator relay, 11 is A
BS motor relay, 12 4WAS warning light, 13 ET
S hydraulic unit, 14 is ETS actuator relay,
15 is an ETS motor relay, 16 is a 4WD warning light, 17
Is a front torque meter.

The throttle opening sensor 1 is a sensor for detecting a throttle valve opening of an engine installed in front of the vehicle by a voltage value, and the first earth 4 in front of the vehicle is used as a reference voltage, and 0% of the throttle opening is detected. 0.5 [V] as throttle opening voltage TVO proportional to 100%
Outputs 5 [V].

The ABS / ETS control unit 2 is a controller that is installed in a trunk room at the rear of the vehicle and performs antiskid brake control (ABS control) and front / rear wheel torque split control (ETS control) in one unit. , Waveform shaping circuit 2a, ABS microcomputer 2b, ETS microcomputer 2c, ABS solenoid drive circuit 2d, ABS solenoid drive circuit 2e, ABS solenoid drive circuit 2f,
ABS fail-safe circuit & relay motor drive circuit 2
g, ETS fail safe circuit & relay motor drive circuit 2h, ETS solenoid drive circuit 2i, ETS torque meter drive circuit 2j, and light emitting diode k. In the ETS microcomputer 2c, a sensor failure detection circuit that detects a sensor failure by monitoring the throttle opening voltage TVO from the throttle opening sensor 1 with the second earth 5 at the rear of the vehicle as a reference voltage is an internal circuit. It has been incorporated.

The ABS actuator 3 includes an ABS solenoid 3a for the right front wheel and an ABS solenoid 3 for the left front wheel.
b, the rear wheel ABS solenoid 3c, and the ABS motor 3
d and.

The battery 6 is installed in the trunk room at the rear of the vehicle together with the ABS / ETS control unit 2.

The ECCS control unit 7 includes
It is a control unit of an engine centralized electronic control system (ECCS) that centrally performs electronic control such as fuel injection, ignition and idle rotation based on input information including throttle opening information.

The wheel rotation sensor 8 is a sensor for providing wheel rule information of each wheel, and includes a front right wheel rotation sensor 8a, a front left wheel rotation sensor 8b, a rear right wheel rotation sensor 8c, and
It has a rear left wheel rotation sensor 8d.

As the G sensor 9, the front and rear G sensor 9 is used.
a and a lateral G sensor 9b.

The ETS hydraulic unit 13 has an ETS solenoid 13a and an ETS motor 13b.

The ABS actuator relay 10, A
The BS motor relay 11 and the 4WAS warning light 12 are AB
When the S fail is detected, the fail safe operation is performed by the command from the ABS fail safe circuit & relay / motor drive circuit 2g.

The ETS actuator relays 14, E
TS motor relay 15 and 4WD warning light 16 are ETS
At the time of fail detection, fail safe operation is performed by a command from the ETS fail safe circuit & relay / motor drive circuit 2h.

The front torque meter 17 is a meter that is provided on the front panel in the vehicle compartment and indicates and supports the torque transmitted to the front wheels.

Next, the operation will be described.

[Sensor Fail Detection Processing Operation] FIG.
Each step will be described below with a flowchart showing the flow of the sensor failure detection processing operation performed by the sensor failure detection circuit incorporated in the TS microcomputer 2c.

In step 30, the throttle opening voltage T
VO is read.

In step 31, the throttle opening voltage T
It is determined whether VO is 0 [V] or less.

In step 32, the throttle opening voltage T
It is determined whether VO is 5 [V] or more.

In step 33, in step 31, TVO≤
0 or when it is determined in step 32 that TVO ≧ 5, ABSFLAG indicating ABS operation / non-operation is A
It is determined whether BSFLAG = 0, that is, whether ABS is not operating. If ABS is operating, the process returns to step 30 even when the sensor fail conditions of steps 31 and 32 are satisfied (sensor failure detection). Equivalent to prohibition means g).

At step 34, Yes at step 33.
s, that is, when it is determined that the ABS is not operated, it is detected that the throttle opening sensor 1 has failed, and the fail-safe operation is executed based on the sensor failure detection.

[When ABS is not operating] When ABS is not operating,
Since the ABS / ETS control unit 2 does not output the drive current to the ABS actuator 3, the reference voltage by the second ground 5 becomes almost 0 [V] as well as the reference voltage by the first ground 4, and the throttle opening voltage T
The VO comparison standard is at the same level.

Accordingly, when the throttle opening sensor 1 is normal, as shown in FIG. 4, the throttle opening voltage TVO is 0.5 to 4.5 [V]. Step 30 → Step 31 → Step 32
The monitoring of the throttle opening voltage TVO is repeated by the flow of.

If the throttle opening sensor 1 fails for some reason, step 31
Alternatively, if the fail judgment condition in step 32 is satisfied, the process proceeds to step 33, and in this step 33, the ABS
It is determined to be Yes because it is not operating, and step 34
At the same time, a failure of the throttle opening sensor 1 is detected, and a predetermined fail-safe operation such as prohibiting the ETS control and turning on the 4WD warning lamp 16 is executed.

[During ABS operation] During ABS operation, AB
Since a large drive current is output from the S / ETS control unit 2 to the ABS actuator 3, the reference voltage by the first ground 4 in front of the vehicle is almost 0 [V], but the reference voltage by the second ground 5 is Since the ground wire has an apparent resistance due to the application of a large current, for example,
The voltage instantaneously rises to 0.5 [V] or more, and the reference voltage, which serves as a reference for comparison of the throttle opening voltage TVO, becomes a difference between the first ground reference voltage and the second ground reference voltage, as shown in FIG. There will be a large level difference.

Therefore, in the detection of the sensor failure on the ABS / ETS control unit 2 side, when the throttle opening voltage TVO is 0 <TVO <5 [V],
In the flowchart of FIG. 3, step 30 → step 31
→ If the flow of step 32 is repeated and it is determined that the throttle opening voltage TVO is 0 [V] or less, the process proceeds to step 30 → step 31 → step 33 in the flowchart of FIG. It is judged No because it is operating, and without proceeding to step 34,
Returning to step 30, the sensor failure detection is prohibited.

Therefore, when a sensor failure is detected by monitoring the throttle opening voltage TVO, although the throttle opening sensor 1 is normal, the first ground reference voltage and the second ground reference voltage are maintained during ABS operation. Due to the large level difference between the voltage and the voltage, for example, when the throttle opening voltage TVO is in the range A in FIG. 4, it is determined that TVO ≦ 0 in relation to the second ground reference voltage, and the sensor fails. If a detection voltage is generated by using a detection processing method that prohibits sensor failure detection during ABS operation that has a high probability of driving with a large current load as described above, a level difference may occur in the reference voltage. The erroneous detection of the sensor failure is prevented.

Next, the effect will be described.

(1) A vehicle-mounted sensor having a layout in which the ground position for taking the reference voltage is separated from the first ground 4 of the throttle opening sensor 1 and the second ground 5 of the ABS / ETS control unit 2 for detecting a sensor failure. In this fail detection device, since the detection of the sensor failure is prohibited during the ABS operation, it is possible to prevent the erroneous detection of the sensor failure caused by the large current load driving from the ABS / ETS control unit 2 to the ABS actuator 3. You can

(2) Since the ABS fail information (ABSFLAG = 1) provided from the ABS microcomputer 2b to the TCS microcomputer 2c is used as a condition for prohibiting the detection of sensor failure, it is determined whether or not a large current load is being driven. It is possible to prevent erroneous detection of a sensor failure by a simple process that does not require judgment.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, the example of the throttle opening sensor is shown as the vehicle-mounted sensor, but it goes without saying that the sensor can be applied to other sensors as long as it outputs an analog signal.

In the embodiment, the vehicle controller is AB
An example of S / ETS control unit is shown, but AB
S control and differential limiting force controlled by clutch engagement force L
The embodiment can be directly applied to the ABS / LSD control unit that also serves as the SD control.
Further, the on-vehicle controller is not limited to the above example as long as it is a controller that drives a large current load on the actuator during control operation.

In the embodiment, the example in which the detection of the sensor failure is prohibited during the ABS operation is shown. However, the drive command output from the in-vehicle controller to the actuator is monitored, and the sensor is detected when it is determined that the high current load is being driven. It may be an example in which the detection of a failure is prohibited.

[0053]

As described above, according to the first aspect of the present invention, the vehicle-mounted sensor has a layout in which the ground position for taking the reference voltage is separated from the vehicle-mounted sensor and the vehicle-mounted controller for detecting the sensor failure. In the fail detection device of, the sensor fail detection circuit of the in-vehicle controller detects that the in-vehicle sensor has failed when the analog signal output from the in-vehicle sensor is out of the normal determination range. Since the sensor failure detection prohibiting means for prohibiting the sensor failure detection is provided, it is possible to obtain an effect that it is possible to prevent the erroneous detection of the sensor failure when the in-vehicle controller drives a large current load.

According to the second aspect of the present invention, the on-vehicle controller is a controller including at least an anti-skid brake controller, and the sensor failure detection inhibiting means is means for inhibiting sensor failure detection during operation of the anti-skid brake. It is possible to prevent the erroneous detection of the sensor failure without the necessity of determining whether or not the high current load is being driven.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a fail detection device for an in-vehicle sensor according to the present invention.

FIG. 2 is a block diagram showing an in-vehicle electronic control system to which the in-vehicle sensor failure detection device of the embodiment is applied.

FIG. 3 is a flowchart showing a flow of sensor failure detection processing operation performed by a sensor failure detection circuit incorporated in the ETS microcomputer of the embodiment.

FIG. 4 is a diagram showing a reference voltage characteristic of a first ground and a second ground and a throttle opening voltage characteristic output from a throttle opening sensor.

[Explanation of symbols]

 a in-vehicle sensor b actuator c in-vehicle controller d first ground e second ground f sensor fail detection circuit g sensor fail detection prohibition means

Claims (2)

[Claims] 1. An on-vehicle sensor that outputs a predetermined physical quantity as an analog signal, and an on-vehicle controller that outputs a drive current to an actuator when control conditions are satisfied, and a reference voltage of the on-vehicle sensor is obtained. The first ground and the second ground for taking the reference voltage of the in-vehicle controller are separated from each other, and the in-vehicle sensor fails in the in-vehicle controller when the analog signal output from the in-vehicle sensor is out of the normal determination range. In a fail detection device for an in-vehicle sensor having a sensor fail detection circuit for detecting that there is a sensor fail detection prohibition means for prohibiting sensor fail detection when a large current load is driven by an in-vehicle controller. Fail detection device for in-vehicle sensor. 2. The fail detection device for an on-vehicle sensor according to claim 1, wherein the on-vehicle controller is a controller including at least an anti-skid brake controller, and the sensor fail detection prohibiting means detects the sensor fail during the operation of the anti-skid brake. A fail detection device for an on-vehicle sensor, which is a prohibition means.