JPS58126441A - Fuel injection controller - Google Patents

Abstract

PURPOSE:To improve an acceleration response in an engine generating an ignition signal three times per two revolutions, by taking off the signal at opening and closing time of a point in an ignition device and dividing the signal into 1/3 frequency to generate one time injection signal per one revolution. CONSTITUTION:A cam 5 comprises three crests in number equal to a number of cylinders, and its distributor shaft is reducibly rotated to 1/2 then a revolution of the cam completes ignition of all cylinders. Opening and closing signals D of a point 4 in this cam 5 are input to a differentiating circuit 7 to become differentiated signals G, and one of the signals is inverted by an inverter 8 while the both signals are fed to a divider circuit 10 through an OR gate 9 and divided to 1/3 frequency, then an injection signal J of one time per revolution is obtained and fed to an injector 11. Accordingly, the injection signal J can be obtained an equal number of times to a six cylinder engine, and a similar response to the six cylinder can be obtained even in a three cylinder engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection control device, and more particularly, to a fuel injection control device that enables injection at every rotation of a small-cylinder engine.

A fuel injection device that injects fuel into the intake pipe is: (1) In general, a simultaneous injection method is used every rotation to simplify the control system for fuel injection amount, and the injection timing is synchronized with the frequency division of the ignition signal. A method is being adopted.

For example, as shown in FIG. 1, in a six-cylinder engine, half of the amount required for combustion in all cylinders is injected in one revolution of the engine, and the remaining half is injected in the next revolution. The injection timing occurs when point voltage A is open, and engine 1
The injection signal C was obtained by frequency-dividing the ignition signal B, which has 3 pulses per rotation, by 173.

However, in the case of a 3-cylinder engine, the injection timing is different from that of a 6-cylinder engine because the ignition signal E, which is generated when the point voltage is open, alternately repeats 2 pulses and 1 pulse for each revolution of the engine. It is not possible to synchronize the injection signal with the frequency division wave of the signal and perform fuel injection once per revolution, so the ignition signal, which has 3 pulses per 2 revolutions, is divided by 1/3 and is injected once per 2 revolutions. This means that fuel injection will be performed. That is, in a three-cylinder engine, the entire amount of fuel for three cylinders is injected once every two rotations of the engine.

(2) Therefore, between a 6-cylinder engine and a 3-cylinder engine, the difference in whether the fuel is injected once per engine revolution or once per two engine revolutions appears as a difference in response time when accelerating. For example, in Figure 1, when both engines accelerate at point a, a 6-cylinder engine will inject an increased amount of fuel at point b after about 1 revolution, but a 3-cylinder engine will inject about 2 revolutions later at point b. Unless the next zero point is reached, an increased amount of fuel will not be injected to match the acceleration. In other words, it can be seen that the response time to acceleration in a 3-cylinder engine is twice as delayed as in a 6-cylinder engine.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection control device for a live-cylinder engine that solves the above-mentioned problems and has good acceleration response.

In order to achieve the above object, the fuel injection control device according to the present invention is designed to control the point opening generated from the ignition device in an engine that generates ignition signals three times in two revolutions to ignite the engine in synchronization with the rotation of the engine. It consists of a signal extraction circuit that takes out the signals for opening and closing, respectively, and a frequency dividing circuit that divides the frequency of the signal (3) three times per revolution of the engine output from the Tfil signal extraction circuit by 1/3. It is configured to use a frequency-divided signal once per revolution of the engine as an injection signal.

According to the above configuration, since injection can be performed once per rotation, the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings and the like.

FIG. 2 is a circuit diagram showing an embodiment of the fuel injection control device according to the present invention, and FIG. 3 is a waveform diagram for explaining the operation of the device.

In Figure 2, 1 is a battery, 2 is a key switch, and 3
is the ignition coil, 4 is the point, 5 is the cam, and 6 is the spark plug. The cam 5 has three peaks, the same number as the number of cylinders, and the destroyer shaft on which the cam 5 is installed reduces the rotation of the engine by half, so one rotation of the cam 5 Complete ignition of all cylinders. Point 4 opens at the ignition timing set by cam 5, the primary current of ignition coil 3 is cut off, and high voltage is generated on the secondary side (4), which is distributed to spark plugs 6 of each cylinder.

In the present invention, not only the signal when the point 4 is opened but also the signal when the point 4 is closed is used as an injection signal. The input terminal of the differentiator circuit 7 receives the point open/close signal of point 4 (
3(D)) is connected, and a differential signal (FIG. 3(G)) when the point is opened/closed appears from the output terminal. One of the branched outputs of the differentiating circuit 7 is inverted by an inverter 8 (FIG. 3(H)) and connected to one input terminal of an OR gate 9, and the other is directly connected to the other input terminal of the OR gate 9. In the OR gate 9, the signals (G), (H)
A signal (FIG. 3 (1)) is obtained which is the logical sum of
is used as an injection signal for the injector 11.

Therefore, the signal (J) is the injection signal of the 6-cylinder engine (
C) (see Fig. 1) can be obtained the same number of times, so even a 3-cylinder engine can obtain the same responsiveness as a 6-cylinder engine. That is, when accelerating at point a (5) in FIG. 3, an increased amount of fuel is injected at point d.

As explained in detail above, in the past, it was considered impossible to inject once per revolution in a three-cylinder engine, but according to the present invention, injection can be performed once per revolution without using a new sensor, etc. The injection interval can be narrowed, and acceleration response can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a waveform diagram for explaining the operation of a conventional fuel injection device, Fig. 2 is a circuit diagram showing an embodiment of the fuel injection control device according to the present invention, and Fig. 3 is a waveform diagram for explaining the operation of the same device. FIG. 1... Battery 2... Key switch 3... Ignition coil 4... Point 5... Camro... Spark plug 7... Differential circuit 8... Inverter 9... OR gate 10・Frequency divider circuit 11・
・Injector (6)

Claims (1)

[Claims] In an engine that generates ignition signals three times in two revolutions to ignite the engine in synchronization with the rotation of the engine, a signal extraction circuit that extracts signals generated from an ignition device when a point is opened and closed; It consists of a frequency dividing circuit that divides the frequency of the signal outputted from the extraction circuit three times per one revolution of the engine by 1/3, and the frequency-divided signal that occurs once per one revolution of the engine is used as an injection signal. A fuel injection control device characterized by comprising: