JP3042264B2 - Failure detection device for in-vehicle sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detecting device for a vehicle-mounted sensor having 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.

[0002]

2. Description of the Related Art Conventionally, as a power supply voltage failure detection circuit, for example, as described in Japanese Patent Application Laid-Open No. Sho 59-213551, a retrigger timer is used to detect a power supply voltage level exceeding an upper limit value. There is known a circuit that detects that the power supply voltage is abnormal when the power supply voltage becomes lower than the lower limit value.

A vehicle-mounted sensor (for example, a throttle opening sensor or the like) that outputs an analog signal based on a voltage value is used for this technique.
If the output voltage level from the in-vehicle sensor becomes higher than the upper limit or lower than the lower limit,
The sensor failure detection circuit detects that the in-vehicle sensor is abnormal.

[0004]

SUMMARY OF THE INVENTION However, in the above-described failure detection apparatus for an on-vehicle sensor, the on-vehicle sensor and a controller having a sensor failure detection circuit for detecting the sensor failure are installed at positions separated from each other, such as the front and rear of the vehicle. In such a case, an in-vehicle sensor that is normal when the controller drives a large current load may be erroneously detected as a failure.

That is, since the ground position for taking the reference voltage is far from the sensor mounted on the vehicle and the controller, the ground wire of the controller has an apparent resistance when driving a large current load on the controller side. If the (ground voltage) instantaneously rises from the original 0 volt and the reference voltage level rises greatly, the output voltage level from the vehicle-mounted sensor is determined to be lower than the lower limit value,
An in-vehicle sensor is erroneously detected as failed.

In particular, when the on-vehicle sensor is a throttle opening sensor disposed in front of the vehicle and the controller is an anti-skid brake controller (hereinafter referred to as ABS controller) disposed in the rear of the vehicle, a plurality of ABS solenoids are operated when the ABS is operated. Often operate at the same time, resulting in a large current load drive, and the throttle opening sensor outputs a low voltage during ABS operation with a low throttle opening. Very likely to be detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object is to provide a layout in which a ground position for taking a reference voltage is separated between a vehicle-mounted sensor and a vehicle-mounted controller for detecting a sensor failure. An object of the present invention is to prevent erroneous detection of a sensor failure when a large current load is driven by an in-vehicle controller.

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

[0009]

In order to achieve the first object, in the fail detecting apparatus for a vehicle-mounted sensor according to the present invention, a predetermined physical quantity is represented by an analog signal as shown in the claim correspondence diagram of FIG. An on-board sensor a for outputting a drive current to an actuator b when the control conditions are satisfied;
The first ground d, which takes the reference voltage, and the second ground e, which takes the reference voltage of the in-vehicle controller c, are separated from each other, and the in-vehicle controller c receives an analog signal output from the in-vehicle sensor a from the normal determination range. In the vehicle-mounted sensor fail detection device having a sensor failure detection circuit f for detecting that the vehicle-mounted sensor a has failed when the vehicle failure is detected, the sensor failure detection circuit f detects the sensor failure when the vehicle-mounted controller c drives a large current load. Is provided with a sensor failure detection prohibiting means g for prohibiting the detection.

According to a second aspect of the present invention, there is provided a failure detecting device for an on-vehicle sensor according to the second aspect, wherein the on-vehicle controller includes at least an anti-skid brake controller. The controller is a controller, and the sensor fail detection inhibiting means g is means for inhibiting sensor fail detection during the operation of the anti-skid brake.

[0011]

The operation of the first aspect of the present invention will be described.

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

On the other hand, when the in-vehicle controller c drives the actuator b with a large current load, the sensor failure detection means f inhibits the sensor failure detection of the in-vehicle sensor a by the sensor failure detection circuit f.

Therefore, when the in-vehicle controller c drives the actuator b with 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 vehicle controller c and the second ground e are separated from each other, the ground wire of the vehicle controller c has an apparent resistance, and the reference voltage rises due to this resistance. Due to the difference between the reference voltage of the in-vehicle sensor a and the normal output from the in-vehicle sensor a, the sensor failure detection circuit f of the in-vehicle controller c erroneously detects that the sensor failure has occurred. Is prevented.

The operation of the second aspect will be described.

When the wheels are likely to be locked during low-μ road braking or sudden braking, a driving command is output from the anti-skid brake controller, which is the vehicle-mounted controller c, to the square wheel actuator b to suppress wheel locking. Anti-skid brake operation is performed. During the operation of the anti-skid brake, sensor failure detection is prohibited by the sensor failure detection prohibiting means g without determining whether or not the drive is a large current load drive.

Therefore, paying attention to the fact that a plurality of actuators b are often driven simultaneously during the operation of the anti-skid brake and inevitably drives a large current load, the sensor failure detection inhibition condition is set under the condition that the anti-skid brake is operating. By this replacement, erroneous detection of a sensor failure is prevented without the necessity of determining whether or not a large current load is being driven.

[0018]

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

First, the configuration will be described.

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

In FIG. 2, 1 is a throttle opening sensor (corresponding to a vehicle-mounted sensor a), 2 is an ABS / ETS control unit (corresponding to a vehicle-mounted 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 is wheel rotation sensor, 9 is G
Sensor, 10 is ABS actuator relay, 11 is A
BS motor relay, 12 is 4WAS warning light, 13 is 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 the throttle valve opening of an engine installed in front of the vehicle based on a voltage value. Using the first ground 4 in front of the vehicle as a reference voltage, 0% of the throttle opening is used. 0.5 [V] as a throttle opening voltage TVO proportional to .about.100%.
5 [V] is output.

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

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

The battery 6 is installed together with the ABS / ETS control unit 2 in a trunk room behind the vehicle.

The ECCS control unit 7 comprises:
It is a control unit of an engine centralized electronic control system (ECCS) that centralizes 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 that provides wheel rule information for each wheel, and includes a front right wheel rotation sensor 8a, a front left wheel rotation sensor 8b, and a rear right wheel rotation sensor 8c.
It has a rear left wheel rotation sensor 8d.

The G sensor 9 includes a front and rear G sensor 9.
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
BS motor relay 11 and 4WAS warning light 12
When an S failure is detected, a fail-safe operation is performed according to a command from the ABS fail-safe circuit & relay motor drive circuit 2g.

The ETS actuator relays 14, E
The TS motor relay 15 and the 4WD warning light 16 are ETS
When a failure is detected, a fail-safe operation is performed according to a command from the ETS fail-safe circuit & relay / motor drive circuit 2h.

The front torque meter 17 is a meter provided on a front panel in the vehicle compartment, for indicating and supporting the transmission torque to the front wheels.

Next, the operation will be described.

[Sensor Failure Detection Processing Operation] FIG.
Each step will be described below with reference to 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 ≦
If 0 or it is determined in step 32 that TVO ≧ 5, ABSFLAG indicating ABS operation / non-operation is A
It is determined whether or not BSFLAG = 0, that is, whether or not ABS is in operation. If the ABS is in operation, the process returns to step 30 even when the sensor failure conditions of steps 31 and 32 are satisfied (sensor failure detection). (Corresponds to the prohibition means g).

At step 34, Ye at step 33
s, that is, when it is determined that the ABS is not operated, the throttle opening sensor 1 is detected as having 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 there is no drive current output from the ABS / ETS control unit 2 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
VO comparison standards are at the same level.

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

If the throttle opening sensor 1 fails for some reason, step 31 is executed.
Alternatively, when the failure judgment condition of step 32 is satisfied, the process proceeds to step 33, and in this step 33, the ABS
If it is not in operation, it is determined as Yes, and step 34 is executed.
As a result, 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 light 16 is executed.

[During ABS operation] During ABS operation, AB
When 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 When the ground wire has an apparent resistance by applying a large current, for example,
The voltage instantaneously rises to 0.5 [V] or more, and as shown in FIG. 4, the reference voltage as a reference for comparing the throttle opening voltage TVO is the difference between the first ground reference voltage and the second ground reference voltage. A large level difference will occur.

Accordingly, when the sensor failure is detected on the ABS / ETS control unit 2 side, if the throttle opening voltage TVO is 0 <TVO <5 [V],
In the flowchart of FIG.
→ The flow of step 32 is repeated, and if 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 determined as No because it is operating, and without proceeding to step 34,
Returning to step 30, sensor failure detection is prohibited.

Accordingly, when the sensor failure is detected by monitoring the throttle opening voltage TVO, the first ground reference voltage and the second ground reference are maintained during the ABS operation even though the throttle opening sensor 1 is normal. When the throttle opening voltage TVO is in the range of A in FIG. 4 due to a large level difference between the voltage and the voltage, for example, it is determined that TVO ≦ 0 in relation to the second ground reference voltage, and it is determined that a sensor failure has occurred. If a level difference occurs in the reference voltage by adopting a detection processing method of prohibiting sensor failure detection during ABS operation that is likely to be driven by a large current load as described above, the detection is erroneously detected. Erroneous detection of the sensor failure is prevented.

Next, the effects will be described.

(1) An in-vehicle sensor having a layout in which a ground position for taking a reference voltage is separated by a first ground 4 of the throttle opening sensor 1 and a second ground 5 of the ABS / ETS control unit 2 for detecting a sensor failure. In the failure detection device of the above, the detection of the sensor failure is prohibited during the ABS operation, so that the erroneous detection of the sensor failure due to the large current load drive from the ABS / ETS control unit 2 to the ABS actuator 3 is prevented. Can be.

(2) As the condition for prohibiting the detection of sensor failure is based on the ABS operating information (ABSFLAG = 1) provided from the ABS microcomputer 2b to the TCS microcomputer 2c, it is determined whether or not a large current load is being driven. The erroneous detection of a sensor failure can be prevented by a simple process that does not require a determination.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and even if there are changes and additions without departing from the gist of the invention, the invention is included in the invention. It is.

For example, in the embodiment, the example of the throttle opening sensor is shown as the on-vehicle sensor. However, it is needless to say that any sensor that outputs an analog signal can be applied to other sensors.

In the embodiment, AB is used as the onboard controller.
Although the example of the S / ETS control unit was shown, AB
L that controls S control and differential limiting force by clutch engagement force
The embodiment can be applied to an ABS / LSD control unit also serving as SD control.
Further, the on-board controller is not limited to the above example as long as it is a controller that drives a large current load to the actuator during the control operation.

In the embodiment, the example in which the detection of the sensor failure is inhibited during the ABS operation has been described. However, the drive command output from the on-vehicle controller to the actuator is monitored, and when it is determined that the vehicle is driven with a large current load, the sensor is detected. An example in which detection of a failure is prohibited may be used.

[0053]

As described above, according to the first aspect of the present invention, a vehicle-mounted sensor having 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 the failure detection device, when the analog signal output from the in-vehicle sensor is out of the normal determination range, the in-vehicle controller detects a failure in the sensor failure detection circuit of the in-vehicle controller. Since the sensor failure detection inhibiting means for inhibiting the sensor failure detection is provided, an effect is obtained that erroneous detection of the sensor failure can be prevented when the in-vehicle controller drives a large current load.

According to the second aspect of the present invention, the onboard 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. An effect is obtained that erroneous detection of a sensor failure can be prevented without the necessity of determining whether or not a large current load is being driven.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating an on-vehicle electronic control system to which the failure detection device for the on-vehicle sensor according to the embodiment is applied.

FIG. 3 is a flowchart showing a flow of a 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 by a first ground and a second ground, and a throttle opening voltage characteristic output from a throttle opening sensor;

[Explanation of symbols]

 a vehicle-mounted sensor b actuator c vehicle-mounted controller d first ground e second ground f sensor failure detection circuit g sensor failure detection inhibiting means

Continuation of the front page (56) References JP-A-59-213551 (JP, A) JP-A-4-148046 (JP, A) JP-A-60-107441 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) G05B 9/02 G05B 23/02 302

Claims (2)

(57) [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 takes a reference voltage of the on-vehicle sensor. The first ground and a second ground for taking the reference voltage of the on-vehicle controller are located at a distance, and the on-vehicle controller fails when the analog signal output from the on-vehicle sensor is out of the normal determination range. An on-vehicle sensor fail detecting device having a sensor fail detecting circuit for detecting that there is a sensor fail detecting circuit, wherein the sensor fail detecting circuit is provided with a sensor fail detecting inhibiting means for inhibiting sensor fail detecting when driving a large current load by an on-vehicle controller. A failure detection device for an in-vehicle sensor. 2. The failure 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 failure detection inhibition means detects the sensor failure during the operation of the anti-skid brake. A failure detecting device for an in-vehicle sensor, which is a prohibiting means.