KR900000149B1 - Fuel injection control method for internal combustion engine - Google Patents

Abstract

The method includes the step of controlling the opening time of a fuel injection valve (3) in accordance with the prestored control program based on various operational parameters. The air intake volume is measured by a hot wire air flow meter (6). A signal of an idle switch (14) is generated to detect a closed state of a throttle valve (5). A valve opening pulse is generated for fuel increment independent of a basic value opening pulse which causes injection valve to inject fuel normally during normal condition. The duration of the opening pulse is controlled dependent on one of parameters selected from variations in air intake volume per unit time, closing signal for throttle value and signal indicating number of revs.

Description

Acceleration Compensation Method of Fuel Injection System

1 is a system diagram of an engine for practicing the present invention.

2 is a block diagram of an input / output relationship shown in the system of FIG.

3 is the injection typing of the engine.

Figure 4 is a graph showing the experimental results showing the rotational rise time between the present invention and the prior art.

5 is a flowchart illustrating an acceleration correction method of the present invention.

* Explanation of symbols for main parts of the drawings

1: engine 3: fuel injection valve

6: hot air flow meter 12: control unit

14: idle switch

The present invention relates to a fuel injection control method for an internal combustion engine, and more particularly, to an acceleration correction method for a fuel injection device for an internal combustion engine for an automobile provided with a hot air flow meter capable of correcting fuel injection amount during acceleration.

Acceleration correction method in the conventional fuel injection device of an internal combustion engine for automobiles is a valve opening pulse generating means for fuel weight independently of the basic valve opening pulse of the fuel injection valve that injects the basic fuel amount at normal time. The valve opening pulse for the fuel weight is determined depending on the engine water temperature (Japanese Patent Laid-Open No. 59-5841).

However, at the time of acceleration in the fuel injection device, no detailed correction of the fuel increase pulse has been made due to the operating conditions of the engine other than the water temperature.

In the electronic fuel injection device (MPI system), a vane type air flow meter is used. For this reason, there is no sudden increase in the amount of intake air of the engine for acceleration, and a relatively thick mixer is supplied at the initial stage of acceleration.

However, good acceleration was not obtained because there was a delay in intake of air to the engine. When the full load acceleration from the children is accelerated, the rise time TO of the rotation is about 200 ms (see Fig. 4).

In addition, when a hot air flow meter is used as the air flow meter, the intake air is not blocked like the vane-type air flow meter, and since the inflow of air into the engine is instantaneously, detailed correction at the time of acceleration is necessary.

In addition, since the hot air flow meter does not have a throttle configuration, the air reaches the engine at the time of acceleration, but the fuel delay is a problem. It is necessary to precisely correct the delay amount of this fuel by the acceleration or the like.

An object of the present invention is to provide an acceleration correction method for a fuel injection device of an internal combustion engine that can obtain good acceleration.

Another object of the present invention is to provide a method for accelerating and correcting a fuel injection device of an internal combustion engine that can correct an increase in fuel due to an operating condition of an engine other than water temperature.

Another object of the present invention is to provide an acceleration correction method for a fuel injection device of an internal combustion engine that can correct a fuel delay.

Another object of the present invention is to provide an acceleration correction method for a fuel injection device of an internal combustion engine that can achieve both acceleration matching after deceleration and normal condition.

Another object of the present invention is to provide an acceleration correction method for a fuel injection device of an internal combustion engine that can shorten the rotational rise time in the case of no-load acceleration from idle time.

Another object of the present invention is to provide an acceleration correction method for a fuel injection device of an internal combustion engine which can improve the lack of acceleration during rapid acceleration after the deceleration stop.

A feature of the present invention is to control the valve opening time of the fuel injection valve according to the control contents preprogrammed by various operating parameters including the intake air amount of the engine, the number of revolutions or the temperature, and measure the intake air amount of the engine with a hot air flow meter. And inputs a signal of an idle switch detecting a closed state of the throttle valve for controlling the intake air amount of the engine, and independently of the basic valve opening pulse of the fuel injection valve for injecting the basic fuel amount at normal In the method for generating a valve opening pulse for increasing, the fuel opening valve opening pulse width is independent of the basic valve opening pulse width, and the amount of change in intake air per unit time, the throttle valve closing signal, the internal combustion engine The acceleration compensation method of the fuel injection device of an internal combustion engine which depended on at least one of the rotational speed signal of the engine. Optimal acceleration can be obtained by changing the correction according to the allocation compensation status during acceleration. Further, by determining the adjustment state after reducing the fuel for deceleration, it is possible to match the acceleration between the state after deceleration and the state after normal operation.

An embodiment of the present invention will be described.

1 is a system diagram of an engine for practicing the present invention. The engine 1 is provided with an intake pipe 2 having a fuel injection valve (injector) 3 corresponding to the number of cylinders. The intake pipe 2 is bundled in the upstream collector 4, and has the throttle valve 5 which determines the intake amount of the engine 1 again upstream.

The intake air amount of the engine 1 is measured by a hot air flow meter 6 provided upstream of the throttle valve 5. On the other hand, the rotation speed of the engine 1 is detected by the rotation sensor 13. In addition, a signal from the engine temperature sensor 11, an exhaust gas signal from the oxygen concentration sensor 10, a signal from the idle switch 14, and the like are input to the control unit CU 12.

The supply of fuel to the engine 1 is performed by opening the valve of the fuel injection valve 3, and the fuel amount is measured by the valve opening time. Fuel is pressurized and adjusted by the fuel pump 8 and the regulator 9.

2 is a block diagram showing the input / output relationship shown in the system of FIG. For the control unit CU, the left side is sensors and the right side is actuators.

In the control unit 12 of FIG. 2, the waveform shaping circuit, the AD converter on the left side, the I / O LSI unit for exchanging input / output and arithmetic processing, and the CPU that sends commands to the I / O LSI unit are in the center. On the right side, a circuit for driving output actuators is arranged.

Next, the injection timing will be described with reference to FIG. 3, taking a four-cylinder four-cycle engine as an example. In general, the injection in a four-cylinder four-cycle engine bundles four cylinders and injects fuel once per revolution, that is, at timings A and C.

The part of A and C is a basic valve opening pulse of the fuel injection valve which injects a basic fuel amount at the time of normality.

The fuel increase pulse (intake pulse) in the present invention is a pulse shown in a portion of B. When acceleration is detected, a fuel increase pulse is generated immediately, and fuel is injected at that timing.

As an acceleration detection method, there are an on / off signal of the idle switch 14 which means that the throttle valve 5 is opened in the idle state, the change amount ΔQa per unit time of the intake air amount Qa, and the like. The magnitude of the acceleration can be detected by the magnitude of the change rate? Qa / Qa of the intake air amount Qa during the adjustment time? T.

Table 1 shows an example of the setting of the fuel increase pulse (intake pulse) in the traveling vehicle with respect to the magnitude of the acceleration.

TABLE 1

For example, the processing after the acceleration is divided according to the state before the acceleration. That is, after the fuel stop at the time of deceleration, a large amount of fuel needs to be supplied in order to satisfy the dry-up of the intake system during the fuel stop. Even in the steady state, it is necessary to change the acceleration compensation amount in the throttle valve fully closed state and others.

The acceleration is detected in combination with the change amount? Qa per unit time of the intake air amount and the idle switch. Idle after in Table 1 is an allocation pulse by acceleration detection by an idle switch.

The acceleration is detected by both the idle switch and the change amount ΔQa of the intake air amount. The reason for this is based on experimental data that the detection in the idle switch is necessarily faster than the detection by the change amount ΔQa of the intake air amount per unit time. The reason for this is that the change amount ΔQa of the intake air amount is larger than the opening of the throttle valve even if the delay of the intake machine is small.

Each representative example is demonstrated as an example. First, the allocation pulse by the change amount (ΔQa) of the intake air amount after the deceleration fuel stop will be described.

37.5%)으로 나누고 완가속시는 3ms, 급가속시는 9ms를 복수회(가속검출할 때마다)할입펄스를 발생한다.After the deceleration of fuel is stopped, under the light acceleration (5% <ΔQa <37.5%) and rapid acceleration (ΔQa)

37.5%), 3 ms for slow acceleration and 9 ms for rapid acceleration, which generates multiple pulses (every time acceleration is detected).

It is preferable that the size of the split pulse is about 1.5-5 ms at full acceleration and about 6-12 ms at rapid acceleration.

The allocation pulse by the idle switch after deceleration fuel interruption set a relatively large value of 9 ms, for example. The size of the split pulse after these idlers is preferably about 6-12 ms.

10%)는 6ms로하여 연료를 분사한다. 이 할입펄스의 크기는 완가속시 1.5-5ms, 급가속시는 약 4-8ms가 바람직하다.3 ms at rapid acceleration (5% <ΔQa <10%) when the acceleration pulse is fully accelerated by the change amount (ΔQa) per unit time of the intake air amount during normal operation (ΔQa)

10%) is 6ms to inject fuel. It is preferable that the size of the split pulse is about 1.5-5 ms at full acceleration and about 4-8 ms at rapid acceleration.

In addition, since there is little dry up of the intake pipe during normal operation (when the idle switch is on), the allocation pulse by the idle switch may be smaller than that at the time of deceleration. The size of this split pulse is preferably about 1.5-5 ms.

When the idle switch is off, that is, the acceleration from the open state of the throttle valve is favorable, such as that the state of the mixer in the intake pipe is uniform compared with the closed state of the throttle valve. For this reason, acceleration compensation at idle switch is unnecessary.

Fig. 4 shows the experimental results based on the results of applying these corrections. 4 is an example of no-load acceleration from children. The rise time of the rotation can be improved to about 120 ms in the present invention (T) by applying the correction of the insertion pulse at the time of acceleration while the conventional type TO is about 200 ms.

5 shows a flowchart art for realizing the correction method described in Table 1. As shown in FIG. First, in acceleration after steady state, the process flow is by the right rope. When the change amount? Qa at the time of normality is smaller than (A1), there is no allocation pulse, and when it is large, the allocation pulse of TA1 is output. Originally, it should be distinguished as A1 '> ΔQa> A1', and the allocation pulse rate should be divided into TA1 '(6ms in Table 1) and (TA1') (3ms in Table 1). I omitted this.

Next, the central loop has an acceleration pulse from the idle, and the allocation pulse (TA2) (3 ms) after idling is set. Then, ΔQa is determined and the allocation pulse TA3 (here also the allocation pulse TA3 '(3 ms in Table 1)) is determined. , TA3 '(6 ms in Table 1) are set.

The loop on the left is the case of acceleration from deceleration. In this case, the allocation pulse TA4 (9 ms) is output after idling, and the acceleration is again determined by (ΔQa). The correction pulse is output by outputting the allocation pulse of (TA6) (3 ms) when A5> ΔQa> A6. Quit.

All of these correction pulses are performed once per acceleration by? Qa. However, in actual engine experiments, there is a problem that the acceleration is insufficient during rapid acceleration after the deceleration stop.

In this invention, this part was also improved. That is, in the case of ΔQa> A5, the allocation pulse TA5 is set. The output of this insertion pulse TA5 is stored, and the correction of the insertion pulse TA5 by the determination of? Qa> A5 can be repeated only under this condition.

Claims (8)

The valve opening time of the fuel injection valve is controlled according to the control contents pre-programmed by various engine operating parameters including the intake air amount, rotation speed and temperature of the engine, and the intake air amount of the engine is measured by a hot air flow meter. Generates the throttle valve closed position signal of the idle switch that detects the closed state of the throttle valve to control the intake air volume of the air, and generates the basic fuel injection valve opening pulse so that the fuel injection valve normally injects fuel in the normal operation state of the engine. And accelerating a fuel injection valve opening pulse for increasing fuel, independently of the basic fuel injection valve opening pulse, wherein the fuel injection valve opening pulse for increasing fuel is the basic fuel. Independent of the valve opening time of the injection valve opening pulse, Air amount, the acceleration correction method of the fuel injector by the engine which is detected from the closed position signal, and at least one change of rotation speed of the internal combustion engine shown sinhojung size of the throttle valve acceleration, characterized in that with the valve open time. The valve opening time of the fuel injection valve is controlled according to the control contents pre-programmed by various engine operating parameters including the intake air amount, rotation speed and temperature of the engine, and the intake air amount of the engine is measured by a hot air flow meter. It generates the throttle valve closed position signal of the idle switch that detects the closed state of the throttle valve to control the intake air volume of the air. A method of accelerating and correcting a fuel injection device comprising: generating a fuel injection valve opening pulse for fuel increase independently of the fuel injection device, wherein the fuel injection valve opening pulse for fuel increase is different from the valve opening time of the basic fuel injection valve opening pulse. Independent of the change in intake air per unit time, the throttle valve closing signal, A valve opening time is caused by at least one of the rotational speed indication signals of the internal combustion engine, and an opening pulse of the fuel injection valve for increasing fuel is generated when acceleration is detected, and fuel is injected at the timing. Acceleration compensation method of injector. 3. The acceleration correction method for a fuel injection device according to claim 2, wherein the acceleration is detected by either the throttle valve closing signal of the idle switch or the change amount of the intake air amount of the engine. 3. The method of claim 2, wherein the fuel injection valve opening pulses for increasing fuel are changed between the slow acceleration and the rapid acceleration states after the deceleration of the fuel is stopped. 5. The fuel injection valve according to claim 4, wherein the fuel is increased by the fuel injection valve opening pulse for fuel increase caused by the acceleration detection by the idle switch and the acceleration detection by the amount of change of the intake air amount per unit time during the acceleration. Acceleration correction method for the fuel injection device. The fuel injection valve according to claim 4, wherein the fuel is increased by the fuel injection valve opening pulse for fuel increase caused by the acceleration detection by the idle switch and the acceleration detection by the amount of change of the intake air amount per unit time during rapid acceleration. Acceleration correction method for the fuel injection device. The fuel injection valve opening pulse for fuel increase caused by the acceleration detection by the amount of change in the intake air amount per unit time when the idle switch in the normal operation of the engine is turned off, wherein the fuel is increased. Acceleration correction method for the fuel injection device. 3. The fuel injection valve opening pulse according to claim 2, wherein the fuel injection valve opening pulse for fuel increase caused by acceleration detection by the idle switch position and acceleration detection by the amount of change of the intake air amount per unit time when the idle switch in normal operation of the engine is on. Acceleration correction method for a fuel injection device characterized in that for increasing the fuel by.

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