JPS60204942A - Fuel injection control device - Google Patents

Abstract

PURPOSE:To invariably maintain a smooth operation state by performing correction control when the fuel injection action for an engine is switched and controlled from sequential injection to simultaneous injection. CONSTITUTION:An internal-combustion engine is provided with a fuel injection valve for each cylinder and switches sequential injection and simultaneous injection for use. A fuel feed quantity correcting means is provided operating only during a transient state when the fuel injection action is switched from sequential injection to simultaneous injection. The fuel feed quantity correcting means invariably maintains the fuel injection quantities to all cylinders equal during a transient state. Thereby, no shock is applied to the operation state of an engine during the switchover, and a smooth operation state of a car can be invariably maintained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a control device for an automobile gasoline engine using a fuel injection method, and particularly to a control device that uses both sequential injection and simultaneous injection for fuel injection and switches between them. The present invention relates to a control device that uses

[Background of the invention]

It is known that fuel injection systems such as four-stroke gasoline engines for automobiles use simultaneous injection systems and sequential injection systems, but conventionally, simultaneous injection systems have been mainly used because they can be easily controlled. It had been. For example, this method is disclosed in Japanese Patent Application Laid-open No. 54-4703.
This is shown in Publication No. 3.

However, the advantages of the sequential injection method, which has excellent control response and is advantageous in terms of improving performance such as low fuel consumption, have been reconsidered, and in recent years, this method has come into widespread use.

By the way, with this sequential injection method, the injection timing is once every two revolutions of the engine (in the case of a 4-cycle engine), whereas with the simultaneous injection method, it is once per engine revolution, but the number of injections is half that. It has become.

Therefore, when it is necessary to increase the amount of fuel supplied when the engine is in a high load state, the control circuit may not be able to adequately handle the situation due to the structure of the control circuit.

Therefore, sequential injection and simultaneous injection are used together. For example, under normal operating conditions, sequential injection is used,
Injection control devices that switch to simultaneous injection only when necessary, such as during heavy loads, have come into use.

However, conventional injection control devices using such a combined switching method have the disadvantage that when switching from sequential injection to simultaneous injection, a large shock is generated in the engine operating state, making it impossible to maintain a smooth operating state. there were.

This will be explained with reference to FIG.

This FIG. 1 shows the stroke operation of each cylinder of a four-cylinder engine, and correspondingly, the fuel injection operation in each cylinder is shown with diagonal lines. The engine is accelerated.

Correspondingly, at time T, the fuel injection method is changed from sequential injection to simultaneous injection.

As is clear from Fig. 1, in the conventional combined switching system, the switching operation is direct, and therefore, the amount of fuel injected between each cylinder is changed during this switching operation. For example, in this figure, the amount is too small and a large shock appears in the engine operating state.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a system in which there is almost no shock in the operating state of the engine even when transitioning from sequential injection to simultaneous injection, and a smooth operating state can always be maintained. The present invention provides a fuel injection control device.

[Summary of the invention]

To achieve this object, the present invention is characterized in that correction control is performed when the fuel injection operation for the engine is switched from sequential injection to simultaneous injection.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel injection control device according to the present invention will be explained in detail below using illustrated embodiments.

FIG. 2 is a timing chart showing the operation of one embodiment of the present invention.
In a cycle engine, a switching condition from sequential injection to simultaneous injection is established at time T, and then at time T.
1 indicates the state in which sequential injection has ended.

Therefore, in this embodiment, instead of immediately transitioning to simultaneous injection after time TI, control is first entered into a control called correction injection at time T, and after that, the transition to simultaneous injection is performed for the first time at time T and I. As a result, even when transitioning from sequential injection to simultaneous injection, differences in fuel injection amount between cylinders are avoided as much as possible.This point will be explained in more detail below.

In FIG. 2, in the reference signal 50, only one wide pulse occurs in every four consecutive pulse trains.
This is for cylinder discrimination. and.

In this embodiment, as an example, the rising time of each pulse of the reference signal 50 is set to be 180 degrees before the top dead center, and this timing will be referred to as REF hereinafter. In addition, the start timing of fuel injection in each cylinder is normally RE
It is set at 170 degrees before dead center (0 degrees after birth after F and 170 degrees before dead center).

Now, in Figure 2, the sequential injection 400 of the 4th cylinder
Hereinafter, the sequential injection of the second cylinder 200. This continues sequentially with sequential injection 100 of the first cylinder.

Here, at time T0, a condition for shifting to simultaneous injection is established in order to increase the fuel injection amount due to an acceleration operation, etc., and control stops sequential injection and shifts to simultaneous injection at sequential injection 300 of the third cylinder that immediately follows. Suppose you enter.

Then, at the time T when this sequential injection 300 ends, the correction injection control region is entered, and first, after the time T, the control region is set at a predetermined time after excluding the cylinder in which injection was performed immediately before (in other words, the third cylinder in this case). , the remaining first cylinder,
The fourth cylinder and the second cylinder are caused to inject an amount equal to the injection amount at the time of sequential injection as shown by 101, 401, and 201. At the next simultaneous injection timing, as shown at 302 and 402, this time only the third and fourth cylinders are made to inject an amount equal to the injection amount in the simultaneous injection. Then, this ends the correction injection and shifts to complete simultaneous injection at the next simultaneous injection timing shown at time T2, and after this time T2, 103, 303, 403
, 203 and following < 104, 304, 404, 20
Control begins to perform simultaneous injection as shown in 4.

Next, as a result of such correction injection control, we will explain how the fuel injection amount in each cylinder changed during the transition period from sequential injection to simultaneous injection. First, the stroke of the third cylinder 31, fuel for one sequential injection is supplied as injection 300, and in the same manner, in the stroke 41 of the fourth cylinder, fuel is supplied as injection 401. The second cylinder stroke 21 is 201. In stroke 1 of the first cylinder, as shown by 101, fuel for one sequential injection is supplied to each cylinder, and in these strokes, the same amount of fuel is supplied, so that the difference between each cylinder is There is no difference in fuel supply amount.

Additionally, each stroke following these strokes
Stroke 32 of the third cylinder and stroke 42 of the fourth cylinder
In this case, injections with the injection amounts at the time of simultaneous injection shown at 302, 303 and 402.403 are performed twice each, and the same is true for the stroke 22 of the second cylinder and the stroke 12 of the first cylinder. , 104, the injection is performed twice at a time, and in the end, there is no difference in the amount of fuel supplied to each cylinder even with these strokes.

Therefore, in this embodiment, even when the operation of the engine injection system changes from sequential injection to simultaneous injection, such as when the car is accelerating, the amount of fuel supplied between each cylinder is always maintained at the same value, resulting in smooth engine operation. It is possible to perform acceleration while maintaining the same state.

Next, to explain in more detail the control necessary for the above embodiment, as shown in the lower part of FIG. For this purpose, in this embodiment, the sequential counter is stopped at time TI and the switching transition time is memorized.

In FIG. 2, each gate signal is configured such that an injection signal is given to the injector of the corresponding cylinder when the gate signal is at a LOW level. On the other hand, the sequential counter operates in the same way as the cylinder counter during sequential injection, but when a switch from sequential injection to simultaneous injection is commanded, it stops counting and stores the cylinder at the time of switching.

Then, the correction injection is performed based on the information of the sequential counter and the cylinder counter, and as mentioned above, the three corresponding gates are opened at the first injection timing after entering the correction injection, and at the second injection timing, the corresponding three gates are opened. Applicable 2
It works to open two gates.

Therefore, the above operation is shown in a flowchart as shown in FIG.

〔Effect of the invention〕

As explained above, according to the present invention, even when the fuel injection operation for the engine is switched from sequential injection to simultaneous injection, such as when the engine is accelerated, the fuel injection amount to all cylinders is always equal. Because you can keep it.

It is possible to easily provide a fuel injection control device that does not cause any shock to the operating state of the engine at the time of switching, and can always obtain a smooth operating state of the vehicle without the drawbacks of the prior art.

[Brief explanation of drawings]

FIG. 1 is a time chart for explaining the operation of the fuel injection device according to the present invention, FIG. 2 is a time chart for explaining the operation of one embodiment of the fuel injection device according to the present invention, and FIG. 3 is a flowchart showing the operation of one embodiment. 11.12, 21, 22, 31, 32.4+.

Claims (1)

[Claims] (1) In an internal combustion engine that is equipped with a fuel injection valve for each cylinder and uses sequential injection and simultaneous injection in combination, only during a transition period when the fuel injection operation is switched from sequential injection to simultaneous injection. A fuel injection control device characterized in that it is provided with an operating #lI supply amount correction means. 2. In claim 1, the fuel supply amount correction means supplies fuel during sequential injection to all fuel injection valves other than the fuel injection valve that performed sequential injection immediately before during the transient period. First, the same amount of fuel is supplied as described above, and then the four fuel injectors that performed sequential injection just before and the fuel injector that would have injected next if sequential injection were to continue. causing only the fuel injection valves to supply a fuel amount equal to the fuel supply amount after shifting to simultaneous injection,
A fuel injection control device characterized in that the device is configured to thereafter shift the operation of all fuel injection valves to simultaneous injection.