JPH0416626B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a low speed fuel control device during deceleration,
In particular, the present invention relates to a low-speed fuel control device during deceleration that easily and reliably controls the cut of low-speed fuel during deceleration by providing a control means that intermittently opens and closes a solenoid valve for opening and closing a slow passage during engine deceleration.

In order to prevent the mixture from becoming too rich or too lean when the engine decelerates, and to prevent afterburn caused by misfires, a solenoid valve is installed in the slow passage to close the passage when the engine decelerates. There is a low-speed fuel control device (Utility Model Publication No. 14826, 1983) during deceleration that cuts off low-speed fuel.

In this control device, a small-diameter fuel supply passage is provided as a bypass in the slow passage in order to smooth the connection to the main system after slow fuel cut and to prevent the air-fuel ratio from becoming excessively lean. However, since this fuel supply passage is uniformly formed, the amount of low-speed fuel cut remains constant.
This method had the disadvantage that it could not improve engine recovery after a slow fuel cut, could not prevent afterfire, and could not efficiently protect the catalyst, improve fuel efficiency, and reduce emissions of harmful components.

Therefore, an object of the present invention is to provide a solenoid valve that opens and closes a slow passage, and to provide a control means that intermittently opens and closes the solenoid valve only when both the intake pipe negative pressure and the engine speed are above a set value. By installing a proportional variable means that changes the intermittent opening/closing time of the solenoid valve in proportion to the engine speed, most of the low-speed fuel is cut off during deceleration, and a portion can be freely adjusted to correct the air-fuel ratio. supply, smooth the connection characteristics to the main system after slow fuel cut, prevent afterfire, and
It is an object of the present invention to provide a low-speed fuel control device during deceleration that can further improve the above-mentioned effects by providing a proportional variable means for increasing the intermittent closing time of the electromagnetic valve in proportion to the engine speed.

Hereinafter, embodiments of the present invention will be described in detail and specifically based on the drawings.

In Fig. 1, 2 is the slow passage of the internal combustion engine;
4 is a solenoid valve, 6 is a valve body of the solenoid valve, 8 is an ignition switch, 10 is an ignition coil, and 12 is a battery. A solenoid valve 4 that opens and closes the slow passage 2 of the slow system is provided, and the valve body 6 of the solenoid valve 4 is installed in the middle of the slow passage 2 so as to be able to protrude and shut off, and when the solenoid valve 4 is in OFF operation, the solenoid valve 4 protrudes and closes. The solenoid valve 4 is configured to move backward and open when the solenoid valve 4 is ON.

Further, the control means 1 opens and closes the solenoid valve 4 intermittently only when the engine is decelerating, that is, when both the intake pipe negative pressure and the engine speed are equal to or higher than a set value.
4, and a proportional variable means 24 for changing the intermittent opening/closing time of the solenoid valve 4 in proportion to the engine speed.

That is, as shown in FIG. 1, a solenoid valve 4 and a battery 12 are connected in series, and an ignition switch 8 is connected in series in this circuit. Further, the rotation sensor 16 and the negative pressure sensor 18 are connected in parallel, and this parallel body is connected in series to the circuit.

The rotation sensor 16 has a break switch function (see Fig. 2) that turns off when the engine speed exceeds a set value, and the negative pressure sensor 18 also has a break switch function that turns off when the engine speed exceeds a set value. Break switch function (3rd
(see figure). Further, the rotation sensor 16 is connected to the ignition coil 10, and its intermittent current is inputted as a signal to detect the engine rotation speed.

Further, a timer 20 is connected in series to the rotation sensor 16.

Furthermore, as shown in FIG. 5, the timer 20 that generates the pulse current is provided with proportional variable means 24 that changes the characteristics of the generated pulses of the timer 20 in proportion to the engine speed. The proportional variable means 24 is arranged in parallel to the rotation sensor 16 and connects the timer 20 and the ignition coil 10.

Specifically, since the return performance of an internal combustion engine is better in the higher rotational speed range of the engine, as shown in FIG. In other words, the OFF time a is set long and the ON time b (pulse width) is set short.

Next, the effect will be explained.

First, during idling, the intake pipe negative pressure is high and exceeds the set value, and the negative pressure sensor 18 is
OFF operates. However, the engine speed is below the set value, and therefore the rotation sensor 16 is turned on, so the circuit including the rotation sensor 16 is closed and a current is applied to the solenoid of the electromagnetic valve 4. Therefore, when the solenoid valve 4 is turned on, the valve body 6 moves backward, and the slow passage 2 maintains its normal open state.
Low-speed fuel in the slow passage 2 is supplied to the combustion chamber from an idle port (not shown) through an intake passage.

During deceleration, both the intake pipe negative pressure and the engine speed exceed the set values, the negative pressure sensor 18 and the rotation sensor 16 are both turned off, and the energization to the solenoid of the solenoid valve 4 is cut off. Ru. Therefore, the valve body 6 of the solenoid valve 4 protrudes and closes, and the slow passage 2 is closed, thereby cutting off the supply of low-speed fuel. This can prevent the mixture from becoming rich and afterburning.

However, if this low-speed fuel cut continues as before, the throttle valve will close completely, leading to a fuel shortage, deteriorating the connection characteristics to the main system after the fuel cut, and causing afterfire due to misfire. Tend. However, in this invention, since a timer 20 that generates a pulse current is also provided, the solenoid valve 4 is driven intermittently.
The slow passage 2 will be intermittently blocked, and the low-speed fuel will be intermittently supplied, albeit in small amounts.

At this time, the proportional variable means turns off the pulse current in proportion to the engine speed, as shown in Figure 5.
Time a is set to be large.

As a result, it is possible to prevent the air-fuel mixture from becoming extremely lean during this period, and it is possible to not only improve the connection characteristics to the main passage but also to prevent afterfire due to misfire.

Further, by setting the timer to a desired time limit characteristic, the intermittent cutoff characteristic can be changed, and the air-fuel ratio during deceleration can be controlled to a desired value.

Furthermore, by providing the proportional variable means 24,
The slow fuel can be reduced in proportion to the engine speed, and precise slow fuel control can be achieved in accordance with engine operating conditions, making it possible to further improve the conventional inconveniences during deceleration.

As is clear from the above description, according to the present invention, a solenoid valve that opens and closes the slow passage is provided, and the solenoid valve is intermittently activated only when both the intake pipe negative pressure and the engine speed are above set values. A control means for opening and closing the valve is provided, and a proportional variable means is provided for changing the intermittent opening and closing time of the solenoid valve in proportion to the engine speed. Prevents the after-fire phenomenon,
In addition to purifying exhaust gas, it can also protect catalyst activity and improve fuel efficiency. Further, a desired air-fuel ratio can be maintained, and the connection characteristics to the main system after fuel cut can be improved. Furthermore, the configuration is simple and the cutting rate can be set over a wide range, so there is a high degree of freedom in design.

Furthermore, slow fuel control can be performed in accordance with the engine speed by means of a proportional variable means that changes the intermittent opening/closing time of the electromagnetic valve in proportion to the engine speed.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing a low-speed fuel control device during deceleration according to an embodiment of the present invention, Fig. 2 is a graph showing the characteristics of the rotation sensor, Fig. 3 is a graph showing the characteristics of the negative pressure sensor, and Fig. 4 is a graph showing the characteristics of the negative pressure sensor. The figure is a graph showing the characteristics of the timer, and FIG. 5 is a graph showing the characteristics of the proportional variable means shown in FIG. 2 is a slow passage, 4 is a solenoid valve, 6 is a valve body, 8 is an ignition switch, 10 is an ignition coil, 12 is a battery, 14 is a control means, 16 is a rotation sensor, 18 is a negative pressure sensor, 20 is a timer ,2
4 is a proportional variable means.

Claims (1)

[Claims] 1 A solenoid valve that opens and closes the slow passage is provided, and a control means is provided that intermittently opens and closes the solenoid valve only when both the intake pipe negative pressure and the engine speed are above a set value, and the solenoid valve is opened and closed intermittently. A low-speed fuel control device during deceleration, characterized in that a proportional variable means for changing a valve time in proportion to the engine speed is provided.