JPH08334080A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Object] In an ignition signal generator used for an internal combustion engine, the ignition signal is prevented from being lost when the engine speed suddenly changes, and an optimum ignition signal is always generated. When the elapsed time from the end side of the pulse signal whose waveform is shaped by comparing the internal combustion engine rotation angle sensor signal with a threshold value by using a comparator 10 matches the ignition timing calculated in advance, the ignition timing Output a signal to the ignition device. At the time interval sufficiently shorter than the set time and at the start side timing of the waveform-shaped pulse signal, the set ignition timer is corrected based on the latest value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine by digital signal processing.

[0002]

2. Description of the Related Art Conventionally, in this kind of ignition timing control system for an internal combustion engine, in order to obtain a precise ignition timing, for example, a reference signal for each 30 ° crank angle and a signal indicating the position of each cylinder are generated. A method has been adopted in which an ignition timer is run from the reference signal to perform ignition.

In another conventional ignition timing control device for an internal combustion engine, a reference position signal of the same number as the number of ignitions of each cylinder is detected at a position which is always a fixed angle before the top dead center of each cylinder. The method of running the ignition timer from this signal was adopted.

[0004]

However, in the conventional ignition timing control device for an internal combustion engine, the use of a plurality of sensors increases the cost due to the restrictions on mounting and the complicated input circuit. There was a problem.
Further, in another conventional ignition timing control device for an internal combustion engine, although the cost can be reduced by simplifying the sensor and the input circuit, on the other hand, the ignition when the setting time of the ignition timer from the reference position becomes long There was a problem that the accuracy of the timing deteriorated.

The present invention solves the above-mentioned conventional problems, and an ignition timing control device of an excellent internal combustion engine capable of generating an accurate and accurate ignition signal even when the rotation changes due to its easy structure. The purpose is to provide.

[0006]

In order to achieve the above object, the present invention corrects the set ignition timer based on the latest value at a constant time interval and at the start side timing of a pulse-shaped pulse signal. It is configured in.

[0007]

Therefore, according to the present invention, by correcting the set ignition timer based on the latest value at the timing of the start side of the pulse signal, it is possible to generate an accurate ignition signal even during a transition.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ignition timing control system for an internal combustion engine according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the present embodiment. In FIG. 1, 10
Is a comparator, 16 is an input terminal, 17 is an output terminal, and 40 is a comparison voltage generator. A sensor signal output from an engine rotation angle sensor (not shown) is input to the input terminal 16, and the signal is processed by an engine rotation angle sensor signal processing circuit configured by the comparator 10 and the comparison voltage generator 40. Input from 17 to a microprocessor (not shown).

Next, the operation of the engine rotation angle sensor signal processing circuit in the above embodiment will be described. In an engine control system using a microprocessor (MPU), a magnetic detection type sensor is often used as an engine rotation angle sensor. Since this magnetic detection type sensor utilizes the fact that the voltage across the detection coil changes due to the change in magnetic flux due to the rotation of the shaft, the sensor output, that is, the sensor signal, is a function of the engine speed. .. In order to use the sensor signal as an input to the MPU, it is necessary to shape the waveform using the comparator 10. The comparison voltage generator 4 generates a threshold value for waveform shaping.
0.

FIG. 2 is a waveform diagram showing the operation of this embodiment, and the operation will be described with reference to FIG. When the engine starts rotating, the rotation signal shown in FIG. 2-A is obtained, and the waveform shaping circuit performs waveform shaping to obtain the waveform shaping signal shown in FIG. 2-B.

On the other hand, the operating conditions are detected from various sensors and the ignition timing is calculated in advance.
The angle information is converted into time information based on the measured rotation speed of the internal combustion engine and set as the ignition timer 2-E. It is assumed that the ignition timing signal is output to the ignition device at the moment when the elapsed time from FIG. 2-C matches the set ignition timer value.

The calculation timing of the ignition timing does not have to be particularly synchronized with the above pulse, and the calculation frequency may be determined according to the capability of the microcomputer used. However, the processing of converting the angle information into the time information based on the measured rotation speed is performed at the timings of FIGS. 2-C and 2-D.

Here, the ignition timer value that has been set once is corrected at a fixed time interval at the timing of FIG. 2-G. The timing of the above-mentioned constant time may be completely asynchronous with the waveform shaping pulse, or may be every constant time from FIG. 2-C in which the ignition timer is set.

The processes performed in FIGS. 2C and 2-D include two processes: recalculation of the ignition timing and correction of the ignition timer. These two processes may be performed at all the timings shown in FIGS. 2-C and 2-D, or may be performed by selecting one of the above timings.

According to the magnetic detection method, the start side of the waveform shaping pulse advances as the rotational speed of the internal combustion engine increases. On the other hand, the calculated ignition timing also generally advances with an increase in the rotational speed of the internal combustion engine, assuming that other operating conditions are constant. Therefore, for each rotation speed, the comparison voltage generator 40 is set so that the start side of the waveform shaping pulse is advanced more than the angle at which the ignition timing is most advanced, and even at the timing of the start side of the waveform shaping pulse. If the ignition timing is corrected again with the latest rotation fluctuation information and the ignition timer is corrected, the correct ignition timing is always reflected in the output even if there is a rotation fluctuation.

As described above, according to the above-described embodiment, since the set time of the ignition timer is short, the delay of the actual ignition timing from the target ignition timing is small even during acceleration, and the output is reduced during acceleration and drivability is improved. It is possible to provide a simple ignition timing control device for an internal combustion engine that does not cause deterioration of the engine.

Although the above embodiment does not refer to the instruction of the energization start timing to the ignition timing control device, it is assumed that the instruction of the energization start timing is given at a time as far back as possible to secure the energization time from the ignition timing. The specific method is determined according to the system to which the present invention is applied.

[0018]

As is apparent from the above embodiment, the present invention compares the internal combustion engine rotation angle sensor signal with the threshold value to shape the waveform, starts the ignition timer from the end side of the pulse, and starts the pulse. The ignition timing is recalculated and the ignition timer is corrected at regular intervals, and therefore, an optimum ignition signal is always generated.

[Brief description of drawings]

FIG. 1 is a block diagram of an ignition timing control device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a waveform chart showing the operation of the embodiment.

[Explanation of symbols]

 10 comparator 16 input terminal 17 output terminal 40 comparison voltage generator

Claims (1)

[Claims] 1. A comparator for comparing an input signal from an internal combustion engine rotation angle sensor with a threshold value, a waveform shaping circuit for outputting a pulse signal from the comparator, and a target ignition timing based on an operating state of the internal combustion engine. Is calculated as the ignition timer time from the end side timing of the waveform shaping pulse, and the ignition timing signal is output to the ignition device when the elapsed time from the end side timing of the waveform shaping pulse matches the ignition timer time. In the timing control device, the ignition timing control device for an internal combustion engine, wherein the set timer value is corrected based on the latest value at a predetermined time interval and the start side timing of the waveform shaping pulse.