JPS63239331A - Electronically controlled fuel injection system for internal combustion engines - Google Patents

Abstract

PURPOSE:To control a decelerating shock, by performing a decelerating fuel reduction at time of deceleration driving when a variation in throttle opening and that in fundamental injection quantity both are more than the specified value, and stopping the decelerating fuel reduction at time of the deceleration driving at a driving range where the fundamental injection quantity variation is less than the specified value. CONSTITUTION:A device bearing the above caption is provided with a setting device C which compensates the fundamental injection quantity set by a setting device B on the basis of output of an engine driving state detecting device A and sets the fuel injection quantity, and drives and controls a fuel injection valve D by the output via a valve driving control device E. In this case, a variation in the throttle valve opening detected by a detecting device F is operated by an operational device G, while a variation of the fundamental injection quantity is operated by an operational device H. And, at time of deceleration driving when an opening variation and a fundamental injection quantity variation both are more than the specified value, the fuel injection quantity is compensated for fuel reduction by a compensating device I, and during this fuel reduction, the opening variation becomes less than the specified value and when the throttle valve opening is more than the specified value, the fuel reduction compensation is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electronic 0;+ control twist 171 injector for an internal combustion engine, and more particularly to fuel injection amount control during deceleration operation.

<Prior Art> Conventionally, electronically controlled fuel injection devices for internal combustion engines include the following.

That is, the basic fuel injection amount Tp (←KXQ/N; is a constant) is calculated from the engine intake air flow rate Q detected by an air flow meter and the engine rotation speed N detected by a crank angle sensor, etc., and then the engine temperature is calculated. After calculating the various correction coefficients C0FE according to the operating conditions of the engine, the air-fuel ratio feedback correction coefficient α, and the correction amount ↑S depending on the battery voltage, the basic fuel injection ITp is corrected and the final fuel injection 1iTi is calculated. (←Tp X COE Xα+Ta)
Set.

Then, by outputting an injection pulse signal with a pulse width corresponding to the set fuel injection amount Ti to the electromagnetic fuel injection valve, a predetermined amount of fuel was injected and supplied to the engine. 59-203828, etc.).

Further, during deceleration operation, the fuel injection amount Ti is reduced during deceleration so as to maintain the air-fuel ratio at an optimum (for example, stoichiometric air-fuel ratio).

Specifically, when the opening change rate or the amount of change of the throttle valve becomes equal to or greater than a predetermined value (negative value), the deceleration reduction fuel amount is subtracted from the fuel injection amount to start deceleration reduction control. Then, from the time when the throttle valve is fully opened, the deceleration reduced fuel amount is gradually brought closer to zero over time, so that only normal fuel injection amount control is performed. Further, when the vehicle shifts to acceleration operation during deceleration reduction control, the deceleration reduction control is stopped.

<Problems to be Solved by the Invention> However, in such a conventional electronically controlled fuel injection system, deceleration reduction control is started when the throttle valve opening change rate reaches a predetermined value or more. Since I was trying to do this, I had the following problem.

In other words, during deceleration operation in which the throttle valve changes from full opening to 1/2 or 1/4 opening (hereinafter referred to as "midway return"), deceleration reduction control is performed even though there is almost no change in the intake air flow rate. starts, the air-fuel ratio becomes lean, causing hesitation or deceleration stagnation, and in the worst case scenario, the lean shift may cause engine seizure.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronically controlled fuel injection device that can prevent the air-fuel ratio from becoming excessively lean and suppress deceleration shock during full deceleration operation.

Means for Solving the Problems> Therefore, as shown in FIG. A detection means A, a basic injection amount setting means B that sets the basic injection amount based on the detected engine operating state, and a fuel that sets the fuel injection amount by correcting the set basic injection amount with various correction amounts. Throttle valve opening for detecting the throttle valve opening of the engine, which comprises an injection amount setting means C and a valve drive control means E for driving and controlling the fuel injection valve based on the set fuel injection amount. Detection means F and opening change rate calculation means G for calculating the detected opening change rate of the throttle valve.
and an injection amount change rate calculation means H that calculates the rate of change of the set basic injection amount, and the calculated rate of change of the opening degree is equal to or greater than a predetermined value, and the calculated rate of change of the basic injection amount is a predetermined value. a deceleration reduction correction means I that starts correction to reduce the set fuel injection amount during deceleration operation exceeding a predetermined value; and a deceleration reduction correction means I that starts reduction correction of the set fuel injection amount; A deceleration/reduction/reduction stopping means J for forcibly stopping the reduction correction is provided.

<Function> In this way, deceleration reduction is performed during deceleration operation when the rate of change in the opening degree and the rate of change in the basic injection amount are equal to or higher than a predetermined value, while the change in intake air flow rate is reduced when the rate of change in the basic injection amount is less than the predetermined value. During deceleration operation in a low operating range, the deceleration reduction is stopped. Further, when the throttle valve opening degree stops at a predetermined value or more during deceleration and reduction, it is determined that the throttle valve has returned halfway, and the reduction control is stopped.

<Example> An example of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, an internal combustion engine 1 has a hot wire air flow meter 7 installed upstream of a throttle valve 3 installed in an intake passage 2.
and an intake passage 2 downstream of the throttle valve 3.
This is a so-called multi-point injection system (MPI system) in which a fuel injection valve 6 is installed in each cylinder.

Here, a rotational speed sensor 4 such as a crank angle sensor that detects the rotational speed N of the engine, and an intake air flow rate Q of the engine l.
An air flow meter 7 for detecting the opening of the throttle valve 3 and a throttle opening sensor 8 serving as a throttle valve opening detection means for detecting the opening of the throttle valve 3 are provided, and each detection signal from these is input to the control device 5 having a built-in microcomputer. do. The control device 5 sets the fuel injection 11Ti of the engine 1 based on these detection signals, and outputs an injection pulse signal having a pulse width corresponding to the fuel injection amount Ti to the fuel injection valve 7.

Here, the control device 5 constitutes basic injection amount setting means, fuel injection amount setting means, valve drive control means, injection amount change rate calculation means, opening degree change rate calculation means, and deceleration reduction stop means. Further, the rotational speed sensor 4 and the air flow meter 7 constitute engine operating state detection means.

Next, the operation will be explained according to the flowcharts of FIGS. 3 and 4.

First, normal fuel injection control similar to the conventional example will be explained. After calculating the basic injection amount Tp based on the intake air flow rate detection signal from the air flow meter 7 and the engine rotation speed detection signal from the rotation speed sensor 4, The basic injection amount is corrected based on water temperature, etc., and the fuel injection amount Ti during normal operation is calculated.
seek.

Next, deceleration reduction control will be explained.

Sl reads various signals from the rotational speed sensor 4, etc.
In S2, the opening change rate Δα is calculated by subtracting the detected previous throttle valve opening from the current throttle valve opening. In addition, the opening degree change flow rate per unit time may be used.

In S3, in the normal fuel injection control, the current basic injection amount tp is subtracted from the calculated previous basic injection amount Tp to calculate the injection amount change rate ΔTp. Note that this may also be the amount of change in injection amount per unit time.

In S4, it is determined whether or not the opening degree change rate Δα calculated in S2 is greater than or equal to a first predetermined value on the negative side, and when YIiS, it is determined that deceleration operation is being performed, and the process proceeds to S5, and when NO, S9
Proceed to.

In S5, it is determined whether or not the injection amount change rate Δ'rp calculated in S3 is greater than or equal to a predetermined value on the negative side. If YES, it is determined that deceleration operation is being performed in an operating range where the intake air flow rate changes, and S6 If the answer is NO, the routine is ended without performing deceleration amount control.

In S6, the deceleration reduction coefficient KDC is calculated based on the cooling water temperature i.
Calculate. The deceleration reduction coefficient KDC is set to decrease as the cooling water temperature increases.

The thus obtained deceleration reduction coefficient KDC is used by being substituted into the following equation in normal fuel injection amount calculation.

Tt=TpXαX (C0EF KDC) + Ts
In addition, α is the air-fuel ratio feedback correction coefficient, C0F
E is various correction coefficients depending on engine operating conditions such as cooling water temperature,
Ts is the correction bone due to battery voltage.

A signal corresponding to the fuel injection amount fi calculated in this manner is output to the fuel injection valve 6, and fuel injection control is performed.

In S7, the deceleration reduction coefficient KDC calculated in S6 is stored in the RAM as the previous deceleration reduction coefficient KKDC.

On the other hand, when it is determined in S4 that the operation is not decelerated,
In S8, it is determined whether the previous deceleration reduction coefficient KKDC stored in the RAM has become 0, and if YES, the routine is ended without passing through S9;
If NO, the process advances to S9.

Note that, in determining whether the deceleration operation has ended, a detection signal from the idle switch is used to determine whether the throttle valve is fully closed.

In S9, A/10 from the previous deceleration reduction coefficient KKDC.
After subtracting (ssec) to obtain the current deceleration reduction coefficient KDC, the routine is ended. A is a constant.

In this way, immediately after the deceleration operation determination ends, the deceleration reduction coefficient KDC gradually decreases to 0 over time.

According to such deceleration reduction control, even during deceleration operation when the rate of change in opening degree of the throttle valve is equal to or higher than a predetermined value, the rate of change in the basic injection amount calculated based on the actual intake air flow rate is the first.
Since deceleration reduction control is not performed when the value is less than a predetermined value, deceleration reduction control is not performed during deceleration operation in the operating range where the intake air flow rate hardly changes even if the throttle valve opening changes (hatched area in Figure 5). Control is not performed. Therefore, during deceleration operation in this operating range, fuel is not reduced, preventing the air-fuel ratio from becoming leaner, and suppressing hesitation and deceleration loss.

Next, the flowchart of FIG. 4 will be explained.

In Sll, it is determined whether or not deceleration reduction control is currently being performed, and YE
If the answer is S, the process advances to 312, and if the answer is No, the routine is ended.

In step 312, it is determined whether or not the opening change rate Δα of the throttle valve has become equal to or less than a second predetermined value during the deceleration reduction control, and YE
When the answer is S, it is determined that the deceleration operation of the throttle valve has been completed, and the process proceeds to 313, and when the answer is NO, the routine is ended.

The second predetermined value is set to be smaller than the first predetermined value.

In S13, it is determined whether the throttle valve opening degree at the end of the throttle valve deceleration operation is equal to or greater than a predetermined value (for example, 5°). If YES, the process proceeds to 314; if NO, the process proceeds to S15.

In S14, the deceleration reduction coefficient KDC is forcibly set to zero.

As a result, the deceleration fuel amount is not added in the fuel injection amount calculation, so the deceleration reduction control is forcibly stopped from this point on.

Therefore, when the throttle valve is not fully closed and the deceleration operation ends in the mid-return state, the deceleration reduction control is forcibly stopped and only normal fuel injection control is performed. Hesitation and deceleration shock can be suppressed.

When the throttle valve opening degree at the end of the deceleration operation is less than the predetermined value, in S14, the deceleration reduction fuel amount is gradually decreased over time in the same way as in S8 and S9 above, and normal fuel injection control is performed.

<Effects of the Invention> As explained above, the present invention starts deceleration reduction control during deceleration operation when the throttle valve opening change rate and the basic injection amount change rate are equal to or higher than predetermined values, and also starts deceleration reduction control at the end of deceleration operation. Since the deceleration reduction control is forcibly stopped when the throttle valve opening is halfway back to a predetermined value or more, it is possible to prevent the air-fuel ratio from becoming leaner and suppress the occurrence of hesitation and deceleration shock.

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Figs. 3 and 4 are flow charts of the same, and Fig. 5 is a diagram for explaining the operation of the same. It is a diagram. 1... Internal combustion engine 3... Throttle valve 4.
...Rotational speed sensor 5...Control device 6...Fuel injection valve 7...Air flow meter 8...Throttle valve opening sensor Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima Figure 3

Claims (1)

[Claims] An engine operating state detection means for detecting an actual engine operating state including at least a parameter related to the flow rate of intake air taken into the engine; and a basic injection amount setting means for setting a basic injection amount based on the detected engine operating state. a fuel injection amount setting means for setting a fuel injection amount by correcting the set basic injection amount by various correction amounts; and a valve drive control for driving and controlling a fuel injection valve based on the set fuel injection amount. In an electronically controlled fuel injection device for an internal combustion engine, the electronically controlled fuel injection device for an internal combustion engine includes: a throttle valve opening detection means for detecting a throttle valve opening of the engine; and an opening change rate calculation unit for calculating a rate of change in the detected throttle valve opening. means, an injection amount change rate calculating means for calculating a change rate of the set basic injection amount, and the calculated opening change rate is a predetermined value or more and the calculated change rate of the basic injection amount is a predetermined value. a deceleration reduction correction means that starts reduction correction of the set fuel injection amount during deceleration operation exceeding a value, and when the opening change rate becomes less than a predetermined value and the throttle valve opening is greater than or equal to the predetermined value during the reduction correction. An electronically controlled fuel injection device for an internal combustion engine, comprising: a deceleration reduction/reduction stop means for forcibly stopping the reduction correction.