JPH04109059A - Automobile sensor diagnostic method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting an abnormality in an automobile sensor.

[Conventional technology]

As described in Japanese Unexamined Patent Application Publication No. 62-247148, the conventional device uses an abnormality detection method to make a determination without distinguishing between steady state and transient state.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the determination conditions for steady state and transient state, and has a problem in determination accuracy.

The present invention aims to determine abnormality of a sensor in the entire driving range of a vehicle, and further aims to improve the determination accuracy.

[Means to solve the problem]

In order to achieve the above object, the conditions for determining abnormality detection are changed between a steady state and a transient state.

[Effect]

The operating state of the vehicle is determined by a throttle sensor, an air amount sensor, etc., and while the transient state continues, the transient state judgment condition is used, and in the steady state, the steady state judgment condition is used. As a result, the judgment conditions for abnormality detection change depending on the operating conditions, so it is possible to improve the judgment accuracy.

〔Example〕

An embodiment of the present invention will be described below. FIG. 1 is a basic configuration diagram of the present invention. A pass/fail determination means for determining pass/fail of each sensor by a means 3 for detecting the output of a sensor 2 that detects an analog quantity of the internal combustion engine 1, a vehicle speed sensor, engine rotation speed, etc., and a means 4 for detecting the operating state from the sensor 2. 5
It consists of more.

FIG. 2 shows a block diagram of the control circuit 10. As shown in FIG.

CPU12. ROM14. The RAM 16 performs calculations such as fuel and ignition control. Vehicle speed sensor 1 is input to input counter A18, and vehicle speed sensor 2 is input to input counter B20. The digital input board 22 contains an idle switch and other switches. The A/D converter 24 includes
It contains flow rate sensors, throttle sensors, etc., and provides basic data for calculating fuel and ignition timing. The digital output boat 26 is connected to a fuel pump relay for controlling on/off of the fuel pump.

The ignition control counter 28 controls the ignition coil, and the fuel control counter 30 controls the injector. In addition to controlling fuel and ignition, the control circuit 10 also diagnoses the sensor switch system and performs pass/fail checks. As an example of this pass/fail check, a determination flowchart for the vehicle speed sensors 1 and 2 will be explained in FIG.

In step 100, the voltage of the throttle sensor is A/D converted and used for determining the operating state. In step 102, the difference between vehicle speed sensors 1 and 2 (vehicle speed difference) is calculated. In step 104, it is determined whether the throttle sensor is in a steady state or in a transient state based on the amount of change in the throttle sensor.

If it is a steady state, the judgment level is set to 5k in step 106.
m/h. If it is a transient state, the determination level is set to 10 km/h in step 108. Based on the above determination levels, the vehicle speed difference and determination level are checked in step 110. If it is within the determination level, both vehicle speed sensors 1 and 2 are determined to be normal in step 112, and the process proceeds to another routine. If the determination level is exceeded, in step 114 the vehicle speed sensor 1,
2 is determined to be abnormal, and the process proceeds to the vehicle speed sensor diagnostic routine.

According to this embodiment, the pass/fail judgment of the vehicle speed sensors 1 and 2 can be made in all driving ranges of the automobile, and prompt response can be made in the event of an abnormality.

In this embodiment, the determination level is changed, but the same effect can be obtained by keeping the determination level the same and making the determination time variable.

〔Effect of the invention〕

According to the present invention, since the determination level is made variable depending on the operating state, there is an effect that the number of determination tanks can be improved.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a block diagram of a control circuit, and FIG. 3 is a flowchart of a control program. 2...Sensor, 4...Operating state detection means, 5...
Pass/Fail Diagram 1

Claims (3)

[Claims] 1. A method for diagnosing an automobile sensor, the method comprising changing diagnostic conditions between a steady state and a transient state. 2. A method for diagnosing a sensor for an automobile, the method comprising making a diagnostic limiter for a transient state larger than a diagnostic limiter for a steady state. 3. A method for diagnosing a sensor for an automobile, the method comprising making a diagnosis time for a transient state longer than a diagnosis time for a steady state.