JPS62142861A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve controllability by effecting optimum correction control, by a method wherein, in a device which performs correction control of an ignition timing through detection of the occurrence of knocking a lead angle per a given time after a delay angle is changed according to the magnitude of knocking. CONSTITUTION:An ignition timing control means has a means 1, setting the control value of an ignition timing based on the operating condition of an engine, and a means 2, correcting the control value of a set ignition timing by means of a correction value. In this constitution, the presence of the occurrence of knocking and the magnitude thereof are detected by a means 3. During the occurrence of knocking, a delay of angle is effected by a full specified delay angle per one ignition by means of a specified correction value with the aid of a means 4. Thereafter, according to the magnitude of knocking, based on a lead angle determined by a means 5, lead of angle is effected by a lead angle responding to the magnitude of knocking per given time by means of a correction value determined by a means 6. This constitution causes execution of optimum correction control responding to the magnitude of knocking.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to an ignition timing control device that detects the occurrence of knocking and corrects and controls the ignition timing.

<Prior art> In a conventional ignition timing control device for an internal combustion engine, an ignition timing control value (ignition advance angle) is set based on engine speed and load, which are parameters of the engine operating state, and the ignition timing control value is set based on this. The ignition timing is controlled by using a knock sensor, and when knocking occurs, knocking is avoided by retarding the ignition timing at a rate of, for example, 1 deg/ignition, and when knocking does not occur, e.g. By correcting the advance angle at a rate of 1 deg/sec, the advance angle is advanced to the knocking limit to improve output performance and the like.

〈Problem to be solved by the invention〉 ``However,
In such a conventional ignition timing control device, after the ignition timing is retarded by a fixed angle per ignition due to the occurrence of knocking, the ignition timing is advanced by a fixed angle per predetermined time regardless of the knocking intensity. Therefore, there was a problem in that the knocking strength was strong but the angle was advanced too quickly, or the knocking strength was weak but the angle was advanced slowly, resulting in poor controllability.

In view of these conventional problems, it is an object of the present invention to improve controllability by performing optimal correction control according to the knocking intensity.

Means for Solving the Problems> Therefore, as shown in FIG. In an ignition timing control device for an internal combustion engine, which includes a correction means for correcting an ignition timing control value by a correction value, and controls the ignition timing based on the corrected ignition timing control value, whether or not knocking occurs due to ignition. a knocking detection means for detecting the knocking intensity; a correction value retard side correction means for correcting the correction value so as to retard the retard angle by a certain amount per ignition when knocking occurs; A lead angle setting means for setting the advance angle of the angle of advance, and a correction value advance angle side correction means for modifying the correction value so as to advance the set advance angle at predetermined intervals. be.

In the above configuration, the knocking detection means detects the presence or absence of knocking and the knocking intensity, and when knocking occurs, the correction value is retarded by a fixed value per ignition with the correction value determined by the correction value retardation side correction means. After the angle is retarded, a correction value is determined by the advance angle setting means based on the advance angle determined by the advance angle setting means according to the knocking strength. Advance the angle. As a result, optimal correction control is performed according to the knocking intensity, and controllability can be improved.

<Example> An embodiment of the present invention will be described below.

Referring to FIG. 2, the engine 1 includes an air cleaner 2°, an intake duct 3. Throttle chamber 4 and intake manifold 5
Air is inhaled through.

An air flow meter 6 is provided in the intake duct 3 to detect the intake air flow rate. The throttle chamber 4 is provided with a throttle valve 7 that operates in conjunction with an accelerator pedal (not shown) to control the flow rate of intake air. The intake manifold 5 is provided with an electromagnetic fuel injection valve 8 for each cylinder, which injects fuel into the engine 1 that is pressure-fed from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator.

The control of the fuel injection amount is calculated by a microcomputer built into the control unit 20 based on the intake air flow rate Q detected by the air flow meter 6 and a signal from a crank angle sensor 9 built into the distributor 12, which will be described later. The basic fuel injection amount 'rp = K・Q/N (K is a constant) is calculated from the engine rotation speed N, and this is corrected appropriately to obtain the fuel injection amount T i =T p −
This is done by setting COEF+Ts (COEF is various correction coefficients, Ts is voltage correction) and applying a drive pulse signal with a pulse width corresponding to this to the fuel injection valve 8 at a predetermined timing in synchronization with the rotation of the engine 1. .

Each cylinder of the engine 1 is provided with an ignition plug lO, to which a high voltage generated by an ignition coil 11 is sequentially applied via a distributor 12, thereby igniting a spark to ignite and burn the air-fuel mixture. . Here, ignition coil 1
1 controls the generation timing of the high voltage through the power transistor lla attached thereto. Therefore, the ignition timing is controlled by controlling the on/off timing of the power transistor lla using an ignition signal from the control unit 20.

For this ignition timing control, the engine speed N calculated based on the signal from the crank angle sensor 9 and the basic fuel injection amount Tp calculated as described above are used as engine operating state parameters. .

Also, a knocking sensor 1 is installed on the cylinder block of engine 1.
This knocking sensor 13 has a piezoelectric element, as shown in Japanese Utility Model Application Laid-open No. 58-180427, etc., and outputs an electrical signal corresponding to the level of vibration of the engine. This output signal is the control unit 2
The signal is input to a knocking detection circuit built into the 0, is processed by this knocking detection circuit, and is then read into a microcomputer to discriminate the presence or absence of knocking and the knocking intensity.

The knocking detection circuit is configured as shown in FIG.
The signal A from the knocking sensor 13 (see FIG. 4) is sent to the buffer 31. The signal is converted into a signal B (see FIG. 4) through a first bandpass filter 32, a second bandpass filter 33, and a mask gate 34 for cutting ignition noise. This signal B is converted into a signal C (see FIG. 4) via a half-wave rectifier amplifier 35 and a mask gate 36 for masking when knocking occurs.

This signal C is converted by an averaging amplifier 37 into a signal D (see FIG. 4). Then, in the comparator 38, a signal E(
A signal F (see FIG. 4) is obtained by comparison with the signal F (see FIG. 4). The presence or absence of pulses in this signal F indicates the presence or absence of knocking, and the number of pulses indicates the knocking intensity.

Then, the output signal F of the comparator 38 is input to an integrator 40, and a signal G (see FIG. 4) is obtained. The level reached by this signal G represents the knocking intensity and is reset in synchronization with ignition.

Then, the output signal G of the integrator 40 is A/D converted by an A/D converter at a predetermined timing and read by the CPU of the microcomputer.

Note that 41 is an ignition signal waveform shaping circuit, 42 is a pulse generator, 43 is an F/V converter, and 44 is a rotation detector.

The CPU of the microcomputer in the control unit 20 performs arithmetic processing according to the flowcharts shown in FIGS. 5 to 7 to control the ignition timing.

The ignition control routine shown in FIG.
It is executed every time a signal is input, and in step 1 (denoted as Sl in the figure, the same applies hereinafter), the output signal G of the integrator 40 representing the knocking intensity is A/D converted and read. The A/D
The conversion timing etc. are as shown in FIG. This step 1 corresponds to knocking detection means together with the knocking sensor 13 and the knocking detection circuit.

In step 2, the presence or absence of knocking is determined based on the A/D conversion value representing the knocking intensity. If knocking is present, the process proceeds to step 3, where the knocking intensity is discriminated into three levels: weak, medium, and strong.

Then, the process branches from step 3 to steps 4 to 6 depending on the level of the knocking intensity, and when the knocking intensity is weak, the advance angle A is set at each predetermined time (Looms) in step 4.
Set DVCON to 0.3 (0.3deg/100m5), and when the knocking strength is medium, set the advance angle ADVCON to 0.2 (0.2deg/100m5) in step 5.
5), and if the knocking strength is strong, proceed to step 6.
to set the advance angle ADVCON to 0.1 (0.1deg/
100m5). The steps 3 to 6 correspond to advance angle setting means.

If there is knocking, the process further advances to step 7, where the current correction value BETA (negative value or O) is changed to a certain retard angle RETCON (for example, 1
deg) to correct the correction value BETA. After this, the process proceeds to step 9 and subsequent steps.

This step 7 and the step 2 correspond to a correction value retard side correction means.

If there is no knocking in step 2, advance angle ADV CON :IC0,1(
0.1deg/Rooms). After this, the process proceeds to step 9 and subsequent steps.

On the other hand, as a Looms process, the routine shown in FIG. 6 is executed every 100 m5, and in order to correct the advance angle in step 21, the current correction value BEITA (negative value or 0) is set in steps 4 to 6 or 8 described above. Set advance angle ADVCO
The correction value BETA is corrected by adding N. This routine corresponds to the correction value advance angle side correction means.

Further, as a background job (BGJ) or as a 10m5 process, the routine shown in FIG. Search the timing control value (ignition advance angle) MADV from the map and set it. This routine corresponds to ignition timing control value setting means.

Returning to FIG. 5, in step 9, limiter processing of the correction value BETA is performed. In other words, the correction value BETA is -5de
Since g≦BETA≦Odeg, if it is outside this range, it is set to the upper or lower limit. Furthermore, the correction value BETA is converted into an integer if necessary.

Then, in step 10, the ignition timing control value MADV based on the engine operating state is corrected by adding a correction value BETA (negative value or 0) to obtain the ignition timing control value ADV. This step 10 corresponds to the correction means.

Then, in step 11, the ignition timing control value (ignition advance angle) ADV is set in the control register, and ignition is performed at that timing.

In this example, when knocking occurs, 1 degree
/ After retarding the ignition, if the knocking strength is weak, the knocking strength is 3deg/sec, if it is medium, it is 2deg/sec.
/sec, if strong, advance at a rate of ldeg/sec.

<Effects of the Invention> As explained above, according to the present invention, since the advance angle per predetermined time after retardation is changed according to the knocking intensity, it is possible to perform optimal correction control according to the knocking intensity. The effect is that controllability can be improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a system diagram showing an embodiment of the invention, Fig. 3 is a block diagram of the knocking detection circuit, and Fig. 4 is the signal waveform in Fig. 3. figure,
5 to 7 are flowcharts, and FIG. 8 is a time chart showing A/D conversion timing, etc. l... Engine 6... Air flow meter 8...
・Fuel injection valve 9...Crank angle sensor 10.
...Ignition plug 11...Ignition coil 12...
Distributor 20...control unit
40...Integrator Figure 2 Figure 5 Figure 6 Figure 7 Figure 8 Fish size reset

Claims (1)

[Claims] The corrected ignition timing control value includes an ignition timing control value setting means for setting an ignition timing control value based on an engine operating state, and a correction means for correcting the set ignition timing control value by a correction value. An ignition timing control device for an internal combustion engine that controls ignition timing based on ignition timing includes a knocking detection means for detecting the occurrence of knocking due to ignition and the knocking intensity, and a knocking detection means for detecting the occurrence of knocking due to ignition and the knocking intensity, and retards the ignition timing by a certain retard angle per ignition when knocking occurs. a correction value retard side correction means for correcting the correction value; an advance angle setting means for setting an advance angle per predetermined time according to the knocking intensity; 1. An ignition timing control device for an internal combustion engine, characterized in that the ignition timing control device for an internal combustion engine is provided with a correction value advance side correction means for correcting the correction value so as to make the correction value angular.