JPS6030473Y2 - Ignition timing control device for spark ignition engines - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ignition timing control device for a spark ignition engine, and in particular, controls the ignition pulse generated in response to engine rotation in response to a knocking signal from a knocking state detection means including a knocking sensor. The present invention relates to an improvement in an ignition timing control device for a spark ignition engine that delays the ignition timing and controls the ignition timing to the maximum advance state that does not cause knocking.

Engine knocking is a dangerous phenomenon that can lead to engine destruction in the worst case scenario, so conventional ignition systems set the ignition timing on the retarded side with some margin from the ignition timing at which knocking occurs. However, setting the ignition timing far beyond the knocking limit is unfavorable in terms of fuel efficiency;
As shown in No. 7, an ignition timing control device has been developed that performs feedback control of the ignition timing to the knocking limit (maximum advance state that does not cause knocking).

By the way, the ignition timing control device as described above detects engine knocking and performs feedback control of the ignition timing.If knocking is detected, the ignition timing is delayed, and if no knocking is detected, the ignition timing is delayed. Although the ignition timing is feedback-controlled to the engine body so that the ignition timing is advanced to the knocking limit, if an abnormality occurs in the knocking sensor, the knocking condition will be detected and the engine will start knocking. The knock sensor's output will output a signal indicating no knock even when the engine is running, causing the ignition timing to advance abnormally, causing severe engine knocking, and in extreme cases, damaging the piston or exhaust valve. This had the disadvantage that it could lead to melting and damage to the engine.

In order to eliminate such drawbacks, for example, when the engine speed is 150 ORPM or more and the output of the knocking state detection means is below the normal background level of 59 mV, it is determined that the knocking sensor or the knocking state detection means is abnormal. It is also possible to use this output signal to set the ignition timing to a predetermined position on the relatively retarded side, regardless of the presence or absence of the knocking signal.

However, in the case of this system, if the level of the detected knocking signal exceeds the above-described determination level of 50 mv due to an increase in engine speed, etc., abnormality detection may no longer be performed and the system may operate normally.

In this case, since the output is low and the ability to detect knocking is low, optimal ignition timing control is not performed, and the ignition timing is controlled to be more advanced than normal, which puts a heavy burden on the engine.

Further, when the detection level of the knocking signal is higher or lower than the determination level, the normal state and abnormal state are repeated, and the ignition timing fluctuates greatly, resulting in a problem that the driving performance of the vehicle is significantly deteriorated.

The present invention has been made to eliminate the above-mentioned drawbacks of the conventional technology, and is designed to reliably set and maintain the ignition timing at a predetermined position on the relatively retarded side in the event that a failure or other abnormality occurs in the knocking state detection means. An object of the present invention is to provide an ignition timing control device for a spark ignition engine that can reliably prevent engine damage such as piston and exhaust valve melting and deterioration of vehicle driving performance.

The ignition timing control device for a spark ignition engine of the present invention delays the ignition pulse generated in response to engine rotation in response to a knocking signal from a knocking state detection means including a knocking sensor, so that knocking does not occur in the ignition timing. In an ignition timing control device for a spark ignition engine, which includes an ignition timing control circuit that controls the ignition timing to a maximum advance state, a knocking state detection section monitoring means outputs a signal when the output of the knocking state detection means is equal to or less than a predetermined value; engine operating state detection means that outputs a signal when the engine is in a preset specific engine operating state; and outputs an abnormality detection signal when the output signals of the knocking state detection means and the engine operating state detection means are input. an abnormal signal generating means for
Abnormality holding means is provided for holding an abnormality detection signal from the abnormality signal generating means and outputting an abnormality holding signal based on the signal, and when the abnormality holding signal is input to the ignition timing control circuit, the abnormality holding means is provided. The ignition timing is configured to be set and maintained at a predetermined retarded position in priority to the knocking signal from the knocking state detection means.

According to the above configuration, when the output of the knocking state detection means exceeds a predetermined value, the knocking signal output from the normal knocking detection circuit is taken into the ignition timing control circuit, and the ignition timing is feedback-controlled to the knocking limit. be done.

On the other hand, if the engine is in a specific operating state, for example, at a specific rotation speed or higher, and the output of the knocking state detection means is below a predetermined value, the knocking state detection means is determined to be abnormal and an abnormality detection signal is generated. The means outputs an abnormality detection signal.

When this abnormality detection signal is input to the abnormality holding means, the state is held and an abnormality holding signal is output to the ignition timing control circuit to set and hold the ignition timing at a predetermined retard position. do.

Therefore, once it is determined that the knocking state detection means is abnormal, the ignition timing will not fluctuate in response to changes in the engine operating state and the detected value of the knocking state detection means, so knocking will occur. can be suppressed, and the engine is reliably protected.

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

As shown in FIG. 1, the first embodiment of the present invention transmits ignition pulses generated in accordance with engine rotation to a knock sensor
Ignition of a spark ignition engine is provided with an ignition timing control circuit 14 that delays the ignition timing in response to a knocking signal from a knocking state detection means consisting of a knocking state detection means consisting of a knocking state detection means consisting of a knocking detection circuit 12 and a knocking detection circuit 12, and controls the ignition timing to the maximum advance state that does not cause knocking. In the timing control device, the engine rotation speed is detected and the engine rotation speed is set to a preset specific engine rotation speed, for example, 15.
16. Engine rotation speed detection means that outputs a signal when exceeding 00 RPM. When the output of the knocking sensor 10 is detected and the output is not within a predetermined range, for example, 59 mV.
Abnormality detection means consisting of knocking sensor monitoring means 18 which outputs a signal in the following cases, and N gates 220 which outputs the AND of the outputs of the engine rotation speed detection means 16 and the knocking sensor monitoring means 18. , an abnormality holding means consisting of a bistable multivibrator 22 that is set by the output of the abnormality detection means and manually reset, holding the abnormality detection signal output from the abnormality detection means;
In response to the abnormality holding signal output from the bistable multivibrator 22, the ignition timing is set and held at a predetermined position sum on the relatively retarded side, regardless of the presence or absence of a knocking signal.

The engine rotation speed detection means 16 is adapted to output a signal when the engine rotation speed reaches 150 ORPM or more, for example, as shown in FIG.

Further, the knocking sensor monitoring means 18 includes, for example, a third knocking sensor monitoring means 18.
As shown in the figure, the output of the knocking sensor 10 is 59mV.
A signal is output when the following conditions occur.

The action will be explained below.

AN
Since the output of the D gate 20 is not generated, the bistable multivibrator 22 is not set, and no abnormality holding signal is output.

Therefore, as in the prior art, the ignition timing is feedback-controlled to the seven knocking limit by the ignition timing control circuit 14 depending on the presence or absence of the knocking signal output from the knocking sensor 10 and the knocking detection circuit 12.

On the other hand, when the engine speed is 150 ORPM or more and the knocking sensor 10 output is 59 mV or less, an output from the AND gate 20 is generated, thereby setting the bistable multivibrator 22.

Then, the ignition timing control circuit 14 adjusts the ignition timing to a predetermined position on the relatively retarded side, regardless of the state of change in the output of the engine rotational speed detection means 16 or the knocking sensor monitoring means 18 thereafter. Set and retained.

This holding state is maintained until the bistable multivibrator 22 is manually reset by the driver, repair shop worker, or the like.

Therefore, even if the abnormality detection signal bunches, the ignition timing does not bunch and the engine can be reliably protected.

A second embodiment of the present invention is shown in FIG.

In the present embodiment, in the ignition timing control device similar to the first embodiment, the abnormality holding means is replaced with an AND which is the abnormality detection means.
a counter 30 that counts the number of outputs of the gate 20;
The comparator 32 outputs an abnormality holding signal until the counter 30 is manually reset when the counter output exceeds a predetermined value n.

The other points are the same as those of the first embodiment, so the explanation will be omitted.

In this embodiment, when the number of outputs of the abnormality detection means counted by the counter 30 exceeds a predetermined value n set by the comparator 32, an abnormality holding signal is output to the ignition timing control circuit 14, From this point on, the ignition timing is set and maintained at a predetermined timing that is relatively retarded, regardless of the subsequent output state of the abnormality detection means.

This holding state continues until the counter 30 is manually reset by the driver or repair shop worker, so that the engine can be reliably protected.

As explained above, according to the present invention, when the knocking state detection means is abnormal, the ignition timing is reliably set at a predetermined position on the relatively retarded side without being affected by the subsequent change in the knocking state detection means.・Since it is retained, it has the excellent effect of reliably protecting the engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the ignition timing control device for a spark ignition engine according to the present invention, and FIG.
FIG. 3 is a diagram showing the change in output of the engine rotation speed detecting means in the first embodiment, FIG. 3 is a diagram showing the change in the output of the knocking sensor monitoring means, and FIG. 4 is a diagram showing the change in the output of the engine speed detection means in the first embodiment. FIG. 2 is a block diagram showing the configuration of a second embodiment of the ignition timing control device of FIG. 10...Knocking sensor, 12...
Knocking detection circuit, 14... Ignition timing control circuit, 16... Engine rotation speed detection means, 18.
...Knocking sensor monitoring means, 20...
・AND gate, 22... Bistable multivibrator, 30... Kalanta, 32... Comparator.

Claims (3)

[Scope of utility model registration request] (1) Ignition that delays the ignition pulse generated in response to engine rotation in response to a knocking signal from a knock jig state detection means including a knocking sensor, and controls the ignition timing to the maximum advance state that does not cause knocking. In an ignition timing control device for a spark ignition engine equipped with a timing control circuit,
knocking state detection unit monitoring means for outputting a signal when the output of the knocking state detection means is below a predetermined value; and engine operating state detection means for outputting a signal when the engine is in a preset specific engine operating state. , an abnormality signal generation means for outputting an abnormality detection signal when the output signals of the knocking state detection means and the engine operating state detection means are input; an abnormality holding means for outputting an abnormality holding signal based on the ignition timing control circuit; An ignition timing control device for a spark ignition engine configured to set and maintain a predetermined retard position. (2) The ignition timing control device for a spark ignition engine according to claim 1, wherein the abnormality holding means is constituted by a bistable multivibrator that is set by the abnormality detection means and manually reset. . (3) The abnormality holding means includes a counter that counts the number of outputs from the abnormality detection means, and when the counter output exceeds a predetermined value, outputs an abnormality holding signal until the counter is manually reset. An ignition timing control device for a spark ignition engine according to claim 1, which comprises a comparator and a comparator.