JPH0914040A - Abnormality detection method for engine rotation sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with a starter signal and a pressure sensor, etc., by judging that a rotation sensor is abnormal when an engine rotation sensor signal is not outputted while an ignition switch is carried out a prescribed circuit ON, OFF operation. SOLUTION: It is judged whether an ignition switch is ON or not and at the yes time, it is judged whether it is just after the change from OFF to ON of the ignition switch or not and at the yes time, after setting an abnormal flag, the existence of the output of the engine rotation sensor is judged. At the no detection time, the ON, OFF operation of the ignition switch is repeated by several times under abnormal flag set state. Then, it is judged whether the ignition switch is switched from ON to OFF or not and in the case of YES and when abnormal flag is set, the operation number of times of the ignition switch from ON to OFF is measured under the abnormal flag set state in order. Then, the abnormality of the engine rotation sensor is judged when the number of times of the ON, OFF operation of the ignition switch is measured more than a prescribed value under the abnormal flag set state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality in an engine rotation sensor that detects engine speed and angle and outputs engine control information such as fuel injection timing.

[0002]

2. Description of the Related Art An electronically controlled engine control system of a vehicle calculates optimum fuel injection timing, ignition timing and the like by using a CPU as one of input information, and the engine speed is an electronic control unit. It is detected by an engine rotation sensor provided in the (ECU). The engine speed sensor is also called an (N + 1) sensor, generates a pulse at every predetermined crank angle (for example, 5 °) to count the engine speed (N) and the angle, and further outputs a pulse at the reference position. This is to know the absolute position (+1) that is generated and serves as a reference.

Here, when the engine rotation sensor is abnormal, the timing of fuel injection and ignition cannot be accurately controlled, and fuel injection cannot be performed so that the engine cannot be started. Therefore, it is necessary to detect the occurrence of an abnormality in the engine rotation sensor at an early stage, and a specific example of the detecting means will be shown below.
First, the rotation of the engine is detected by the starter signal output by operating the starter motor, and in that state, the engine rotation sensor output signal is detected together with the starter signal. And
If the engine rotation sensor output signal is not detected, it is determined that the engine rotation sensor is abnormal.

Alternatively, the rotation of the engine is detected by the pressure sensor signal output by the pressure change in the cylinder,
In this state, the output signal of the engine rotation sensor is detected together with the output signal of the pressure sensor to similarly detect the occurrence of an abnormality in the engine rotation sensor.

[0005]

A problem to be solved by the invention is that since the starter signal and the wiring of the pressure sensor are required for detecting the abnormality of the engine rotation sensor, respectively, the cost is high. If is not originally installed, it is costly to install the pressure sensor only for detecting the abnormality of the engine rotation sensor.

[0006]

The present invention is characterized in that if the engine rotation sensor signal is not output while the ignition switch is turned on and off a predetermined number of times, it is determined that the engine rotation sensor is abnormal. To do.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an abnormality detecting method for an engine rotation sensor according to the present invention will be described below with reference to FIGS. 1 (a), 1 (b) and 1 (c). First, FIGS. 1 (a), 1 (b), and 1 (c) show an abnormality flag setting routine, an abnormality counting routine, and an abnormality detection routine of the engine speed sensor, respectively. The feature of the present invention is that, when the ignition switch (IG switch) is switched from OFF to ON a predetermined number of times, it is assumed that the start has been reached at least once, and the ON signal is always sent from the ECU or various electric systems. In order to take it out, when the ignition switch is turned on and off a predetermined number of times and the ON signal for the number of times of operation is detected by the ECU or the like, it is detected whether or not the engine rotation sensor signal is output during that time. Then, if detected, the engine speed sensor is normal, and if not detected, it is determined that an abnormality has occurred.

[0008]

EXAMPLE First, as shown in the routine of FIG. 1A, it is judged whether or not the ignition switch is ON. If the answer is negative (No), the routine operation ends, and if the answer is affirmative (Yes). , ECU, etc., determines whether or not the state of the ignition switch has just changed from OFF to ON. If the answer is no, the timer counts up and the elapsed time is measured, and if the answer is yes, the timer is set and the abnormality counter is set. Therefore, it is determined whether or not the time has elapsed for 2 seconds or more. If the answer is negative, the above routine is repeated until 2 seconds is reached. If the answer is affirmative, the abnormality flag is set and then the engine speed sensor signal Determine whether to output. When the answer is positive and the engine rotation sensor output signal is detected, the abnormality flag set and the abnormality counter are cleared, and it is determined that the engine rotation sensor is normal. If the engine rotation sensor output signal is not detected, the abnormality flag setting routine is repeatedly executed with the abnormality flag set. In the abnormality counting routine shown below, the number of ON / OFF operations of the ignition switch in the abnormality flag set state, that is, in the state where the engine rotation sensor signal is not output, is counted.

Therefore, as shown in the routine of FIG. 1 (b), it is judged whether or not the ignition switch is switched from ON to OFF. If the answer is negative, the routine operation ends, and if the answer is affirmative, the timer is terminated. Is cleared to determine whether the abnormality flag is set. When the answer is affirmative, the number of times of ignition switch operation is increased and accumulated, and the number of times of ignition switch operation from ON to OFF in the abnormality flag set state is sequentially counted. If the result is negative (no abnormality flag set), the count is passed and accumulated.

Next, in the routine of FIG. 1 (c), the number of times the ignition switch is turned on and off in the abnormal flag set state is judged, and if it is counted three times or more, there is no output of the engine rotation sensor signal during that period. It is determined that the engine rotation sensor is abnormal. If it is less than 3 times,
The operation of the abnormality detection routine ends.

It should be noted that the ignition switch is turned on and off by judging the number of times of operation is 3 or more. If the number of times of turning on and off is repeated 3 times, the starter operates once and the engine is started. It is based on the statistical inference that it may be rotating and the request to detect the sensor abnormality promptly. In consideration of the specific situation of the ignition switch operation, 4 times or more, 5 times or more, or 2 times or more. It is also possible to judge.

[0012]

According to the present invention, when the abnormality of the engine speed sensor is detected, the ignition switch is turned on a predetermined number of times.
If the engine rotation sensor output signal is not detected during the N, OFF operation, it is determined that the engine rotation sensor is abnormal, so the starter signal, pressure sensor, etc. are not required and wiring is simplified. , The cost is reduced.

[Brief description of the drawings]

1A, 1B, and 1C are an abnormality flag setting routine, an abnormality counting routine, and an abnormality detection routine, respectively, showing an embodiment of an abnormality detection method for an engine rotation sensor according to the present invention.

Claims (1)

[Claims] 1. The ignition switch is turned on a predetermined number of times.
A method for detecting an abnormality of an engine rotation sensor, wherein when there is no output of the engine rotation sensor signal during the N, OFF operation, it is determined that the engine rotation sensor is abnormal.