JPS59194078A - Ignition timing controller of internal-combustion engine - Google Patents

Abstract

PURPOSE:To perform rapid lead angle return and to improve the acceleration operability of an engine, by a method wherein, in case the occurrence of knock ceases during a given time, the lead angle return speed of an ignition timing is increased. CONSTITUTION:A device is constituted such that the output signal of a knock sensor 1 is compared with the output signal of a comparision voltage generator 2, which outputs a d.c. voltage, being slightly higher than the level of the noise component of the former signal, through the working of a comparator 3, and a pulse train signal is outputted during the occurrence of knock. This device is provided with an integrator 4 for integrating a pulse train and a timer 6 which shifts the output voltage drop speed of the integrator 4. An angle of delay control is made on an ignition timing by an ignition timing controller 5 according to the output of the integrator 4, and when a given time T elapsed after the occurrence of knock ceases and the outputs of the timer 6 is inverted to an L- level, the drop speed of the output voltage of the integrator 4 is shifted to a high mode to enable rapid lead angle return of an ignition timing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for an internal combustion engine that controls ignition timing by detecting engine knock.

An ignition system that detects knock-specific signals from internal combustion engine vibrations and changes in cylinder pressure, determines the occurrence of knock from the signals, and retards the ignition timing if knock occurs to suppress engine knock. Timing control devices are known.

A conventional example of this type of ignition timing control device is shown in FIG. In FIG. 1, 1 is a knock sensor that detects engine knock, and 2 is a comparison voltage generator that generates a comparison voltage according to the output signal level of knock sensor 1, which is compared with the output signal level of knock sensor 1. A comparator 3 compares the comparison voltage output from the voltage generator 2.

The output signal of the comparator 3 is integrated by an integrator 4. Depending on the output voltage of the integrator 4, an ignition timing controller 5 determines the ignition timing based on parameters such as engine speed and load condition.

2(a) to 2(c) show the operation of the block diagram of FIG. 1. FIG. The output signal waveform of the knock sensor 1 is shown in Figure 2 (a
) shows a vibration waveform, and when there is no knock, a relatively low level noise component is output, and when knock occurs, a large amplitude signal is output in synchronization with the occurrence of knock.

Therefore, according to the level of the noise component of the output signal of the knock sensor 1, the comparison voltage generator 2 outputs a DC voltage that is slightly higher than the level of the noise component as the comparison voltage, as shown in FIG. Otsu.

Comparator 3 compares the output signal of knock sensor 1 and the comparison voltage output from comparison voltage generator 2 . As shown in FIG. 2(b), when there is no knock, the output signal of the knock sensor 1 is only a noise component and does not exceed the comparison voltage level output from the comparison voltage generator. outputs nothing.

Furthermore, when a knock occurs, a large-amplitude signal is superimposed on the noise component of the output signal of the knock sensor 1, which exceeds the comparison voltage level, so the comparator 3 responds to the large-amplitude signal of the knock. Outputs a pulse train.

An integrator 4 integrates the pulse train, resulting in a
The output voltage of the integrator 4 increases as shown in C), and the ignition timing controller 5 retards the ignition timing in accordance with the output voltage level. Therefore, the occurrence of knocking in the engine can be suppressed.

Further, when the knocking stops occurring, the output voltage of the integrator 4 decreases at a predetermined speed, and the ignition timing is returned to the original advance side.

Here, in the ignition timing control for knock control, the ignition timing retardation speed is set quickly in order to increase the control response when knocking occurs, and the ignition timing advance recovery speed is set to improve the control stability of the knock limit. It is common to set it relatively late.

However, with the above settings, during transient operation, especially when the engine speed and load condition change over a short period of time, such as during acceleration operation, the state of knock occurrence also changes moment by moment. An example of this is shown in FIG.

FIG. 3(a) shows the output signal waveform of the knock sensor 1.
Indicates the state of knock occurrence. And Figure 3(b)
is the output voltage of the integrator 4 due to the occurrence of knock in FIG. 3(a), and shows the change in the ignition timing retard amount.

According to FIG. 3, in the region (A) of FIG. 3 where initial knock occurs, the ignition timing is retarded with good response, and the occurrence of knock is immediately suppressed. ]
Even if the engine moves to part ), the fall in the output voltage of the integrator 4 is relatively slow, so even though knocking does not occur, the ignition timing is unnecessarily retarded, resulting in poor engine acceleration performance. there were.

Therefore, in order to solve the above-mentioned problems, the present invention increases the speed at which the ignition timing returns to advance when no knock occurs for a predetermined period of time, so that the ignition timing is quickly returned to the advance, thereby eliminating wasteful retardation. It is an object of the present invention to provide an ignition timing control device for an internal combustion engine that prevents this.

Embodiments of the ignition timing control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. FIG. 4 is a block diagram showing the configuration of one embodiment.

In FIG. 4, in order to avoid misunderstandings, parts that are the same as those in FIG. 1 are given the same reference numerals and their explanations are omitted, and parts that are different from those in FIG. 1 will be mainly described.

As is clear from comparing Figure 4 with Figure 1,
In the figure, a timer 6 is newly added to the configuration of FIG. 1. This timer 6 has a trigger input connected to the output of the comparator 3, an output connected to the integrator 4, and switches the output voltage fall rate (advance return speed) of the integrator 4.

The cono timer 6 is triggered by the output pulse of the comparator 3, and keeps the output level of the timer 6 at a high level for a predetermined time T. If a pulse is output from the comparator 3 while the output of the timer 6 is at a high level, the timer 6 is retriggered.

When the output of the timer 6 is at a high level, the rate of fall of the output voltage of the integrator 4 is set to a relatively slow mode. When the level is low, it can be switched to a faster mode.

Next, the operation of the ignition timing control device for an internal combustion engine of the present invention configured as described above will be explained with reference to FIGS. 5(a) to 5(d). Figures 5(a) to 5(C)
) correspond to FIGS. 2(a) to 2(c), respectively. Further, FIG. 5(d) shows the output waveform of the timer 6. The engine is now being accelerated as in the case of FIG. During the initial knock occurrence period (section A in FIG. 5), by detecting knock, the output voltage of the integrator 4 increases responsively as shown in FIG. 5(c), thereby suppressing the occurrence of knock. Then, when the knocking stops occurring (B in Figure 5)
The output voltage of the integrator 4 starts to fall from the point (section) onwards.

On the other hand, since the comparator 3 generates a pulse due to the initial knock occurrence, the timer 6 is triggered by the pulse 9.
The output is held at a high level for a predetermined time T. When the initial knock occurs at an interval shorter than the predetermined time T of the timer 6, the output of the timer 6 is maintained at a high level during the initial knock occurrence period as shown in FIG. 5(d).

Therefore, during this period, the rate of fall of the output voltage of the integrator 4 is relatively slow, and the ignition timing slowly returns to the advanced position. Then, when the knocking stops occurring and a predetermined time T elapses, the output of the timer 6 is reversed to a low level, so the output voltage of the integrator 4 switches to a fast mode, and the ignition timing changes to a fast mode. Advance angle returns.

As a result, in the conventional example shown in FIG. 1, even if the knocking stops, as shown in FIG. In the embodiment of the present invention shown in FIG. 5(c), as soon as the knocking stops, the advance angle is returned to normal, thereby eliminating unnecessary retardation and preventing a drop in engine output. I can do it.

Also, during steady operation to control to the knock limit, the timer 6
If the predetermined time TF is set to be longer than the knock occurrence interval, the output of the timer 6 will not fall to a low level, so the falling speed of the output voltage of the integrator 4 will be in a relatively slow mode. It is fixed and does not impair control stability.

Note that in the above embodiment, the ignition timing is returned to advance continuously, but in a device that advances the ignition timing in stages, the amount of advance or the interval at which the ignition timing is advanced may be switched. By doing so, the present invention can be implemented.

In the above embodiment, the timer 6 switches the sweepback angle return speed for a predetermined time T after the occurrence of knock, but a counter is provided in place of the timer 6 to count the ignition signals and There is also a method of switching the advance return speed after a predetermined number of ignitions from the time when the engine stops.

Furthermore, in the above embodiment, the mode was switched to a mode that increases the advance angle return speed, but if the advance angle return speed is increased infinitely, the mode is changed to a mode that resets the retard angle control amount to the advance angle side. You may switch.

As described above, according to the ignition timing control device for an internal combustion engine of the present invention, when the engine shifts to an operating range in which knock does not occur during transient operation, the ignition timing advance return speed is increased to avoid wasted waste. This has the effect of eliminating retardation and preventing a drop in engine output.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional ignition timing control device for an internal combustion engine, and FIGS. 2(a) to 2(c) are operational waveform diagrams of the ignition timing control device for an internal combustion engine shown in FIG. figure(
a) and FIG. 3(b) are operational waveform diagrams during transient operation of the engine in the ignition timing control system for the internal combustion engine shown in FIG.
The figure is a block diagram showing the configuration of an embodiment of the ignition timing control device for an internal combustion engine according to the present invention.
d) is an operation waveform diagram of the ignition timing control device for an internal combustion engine according to the present invention. 1... Knock sensor, 2... Comparison voltage generator, 3.
... Comparator, 4... Integrator, 5... Ignition timing controller, 6... Timer. In addition, the same reference numerals in the figures indicate the same or corresponding parts. (Spontaneous) 1. Indication of the case Japanese Patent Application No. 58-70455 2. Name of the invention Ignition timing control device for internal combustion engine 3. To the representative Hitoshi Katayama of the person making the amendment 4. Claims in the attorney's specification Column and details of the invention 6, Contents of amendment (1) Scope of claims? Amend as shown in the attached sheet. (2) Add "output of integrator 4" to ArJ for "stepwise" on page 8, line 20. The step of changing the voltage [by changing the voltage to a lower level or by using a 40-meter integrator instead of an integrator 40,
”? join. 7. List of attached documents Patent claims One or more copies of claims organization knocking? Knock sensor to detect, comparison voltage according to the output voltage level of this knock sensor? a comparison voltage generator that generates a comparison voltage, a stage that compares the comparison voltage with the output signal of the knock sensor and outputs a pulse train r corresponding to the amplitude of the knock when a knock occurs, a predetermined period of time depending on the output voltage level of the integrating means; An ignition timing control means for an internal combustion engine, comprising an ignition timing control means for increasing the speed or angle at which the ignition timing of the internal combustion engine is fully advanced when no knock occurs.

Claims (1)

[Claims] A knock sensor that detects engine knock, a comparison voltage generator that generates a comparison voltage according to the output signal level of this knock sensor, and a comparison voltage generator that compares this comparison voltage with the output signal of the knock sensor and detects the knock when knock occurs. A comparator that outputs a pulse train according to the amplitude, a timer that is triggered by the output of this comparator and holds the output level at a high level for a predetermined time, and a timer that integrates the output of the above comparator and when the output of the above timer is at a high level. An integrator that is set in a mode with a slow output voltage fall rate and when the timer output reaches a low level, switches to a mode with a slow output voltage fall rate, and no knock occurs for a predetermined period of time in response to the output voltage level of this integrator. An ignition timing control device for an internal combustion engine, comprising an ignition timing controller that increases the speed or angle at which the ignition timing of the internal combustion engine is advanced or restored.