JPS5949334A - Acceleration/deceleration correction in electronically controlled fuel injector for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent erroneous correction on the basis of erroneous decision of acceleration/deceleration, by providing means for stopping the function of an acceleration/deceleration correcting means for predetermined time after correction. CONSTITUTION:A deceleration timer 18 for stopping the correcting function is provided in an acceleration correcting circuit 14 and set through the correcting operation of a deceleration correcting circuit 15, thereby upon completion of decelerating correction counting is started to stop the function of said circuit 14 for predetermined time. While an acceleration timer 19 for stopping the correcting function is provided in said circuit 15, and upon completion of accelerating correction the function of said circuit 15 is stopped for predetermined time. Consequently even if there is erroneous decision of acceleration/deceleration due to overshoot of the output signal U/ub from an air flow meter 12, correction based on erroneous is decision is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically controlled fuel injection device for an internal combustion engine. This invention relates to a correction device.

Conventionally, electronically controlled fuel injection systems for internal combustion engines determine the basic injection amount of fuel based on the intake air flow rate detected from the output signal of the airflow make and the engine speed detected from the ignition signal of the ignition coil. The optimum fuel is supplied to the engine by generating a corresponding basic pulse and driving the fuel injection valve via a drive circuit using the fuel injection pulse obtained by appropriately correcting this pulse.

Here, as one of the above corrections, acceleration/deceleration correction is performed, which determines acceleration or deceleration by capturing changes in the output signal of the airflow meter, and corrects the basic pulse accordingly to optimize the By obtaining accurate fuel injection pulses, an appropriate air-fuel ratio is maintained during acceleration and deceleration, thereby preventing deterioration of exhaust characteristics.

On the other hand, an air flow meter for measuring the intake air flow rate is configured as shown in FIG. The flap 1 rotates to an angle at which the return torque of the spring 2 is balanced. The rotation angle position of the flap 1 at this time is converted into a voltage signal by the potentiometer 3, and becomes an output signal. Here, the output signal is generally expressed as U/Ub and corresponds to the reciprocal of the intake air flow rate. U is a divided voltage value by the flap 1, and Ub is a reference voltage value. Note that 4 is a damper and 5 is a damper chamber.

However, when performing acceleration/deceleration correction using the output signal of such an air flow meter, the intake air flow rate changes due to throttle valve operation (accelerator pedal operation).
By rotating the flap 1 of the air flow meter in accordance with the flow rate, a corresponding output signal U/Ub is obtained. However, when the intake air flow rate changes, the inertia of the flap 1 causes the change to be accurately reflected by U/Ub. /Ub value may not correspond.

That is, an overshoot (or undershoot) of the U/Ub value as shown in Fig. 2 occurs, and therefore, for example, when accelerating, an acceleration judgment and a deceleration judgment (Fig. 2A) occur.
2), and at the time of deceleration, an acceleration determination (section B in FIG. 2) is performed at the same time as a deceleration determination, making it difficult to make an appropriate correction.

The present invention has been made to solve these conventional problems, and includes means for stopping the function of the deceleration correction means for a certain period of time after acceleration correction, and a function of the acceleration correction means for a certain period of time after deceleration correction. By providing a means for stopping the U/Ub value, it is possible to prevent erroneous correction from being made based on an erroneous determination of acceleration/deceleration due to overshoot of the U/Ub value.

An embodiment of the present invention will be described below.

In FIG. 3, the ignition signal (rotation pulse) corresponding to the engine speed N from the ignition coil 11 and the output signal U/Ub (reciprocal of the intake air flow rate Q) of the air flow meter 12 are sent to the basic pulse generation circuit 13. The basic pulse generation circuit 13 calculates the basic injection amount K·(Q/N) of fuel from these signals and generates a basic pulse corresponding to this.

An acceleration correction circuit 14 is connected to the output terminal of the basic pulse generation circuit 13.
is connected to the output terminal of the acceleration correction circuit, and the deceleration correction circuit 1 is connected to the output terminal of the acceleration correction circuit.
5 is connected. A drive circuit 16 is connected to the output end of the deceleration correction circuit 15, and an electromagnetic fuel injection valve 17 is connected to the output end of the drive circuit 16.

Here, the basic pulse generated by the basic pulse generation circuit 13 passes through the acceleration correction circuit 14 and the deceleration correction circuit 15 as it is, except during acceleration/deceleration (that is, during steady state), and becomes a fuel injection pulse. The drive circuit 16 drives the fuel injection valve 17 in response to the fuel injection pulse.

The output signal U/Ub of the air flow meter 12 is input to the acceleration correction circuit 14, and the output signal U/Ub is inputted to the acceleration correction circuit 14.
Acceleration is determined from the amount of change Δ(U/Ub) in Ub, and at this time, a fuel injection pulse that is an increase-corrected basic pulse is output.

This acceleration correction circuit 14 is provided with a deceleration timer 18 for stopping its correction function, and this deceleration timer 18 is set by the correction operation of the deceleration correction circuit 15, so that when the deceleration correction is completed, A count is started and the function of the acceleration correction circuit 14 is stopped for a predetermined period of time.

The output signal U/Ub of the air flow meter 12 is also input to the deceleration correction circuit 15, and deceleration is determined from the amount of change Δ(U/Ub) in the output signal U/Ub.
At this time, a fuel injection pulse obtained by reducing and correcting the basic pulse is output.

This deceleration correction circuit 15 is provided with an acceleration timer 19 for stopping its correction function, and this acceleration timer 19 is set by the correction operation of the acceleration correction circuit 14, so that when the acceleration correction is completed, A count is started and the function of the deceleration correction circuit 15 is stopped for a predetermined period of time.

According to this configuration, during acceleration as shown on the left side of FIG. 2, the acceleration correction circuit 14 operates to perform acceleration correction due to changes in the U/Ub value, and at this time, due to overshoot of the U/Ub value, the Even if deceleration is determined, at this time the acceleration timer 19 has already been counted and the set time is within its set time, so the acceleration timer 19 does not cause the deceleration correction circuit 15 to operate, and therefore no deceleration correction is performed.

Further, during deceleration as shown on the right side of FIG. 2, the deceleration correction circuit 15 operates due to changes in the U/Ub value, and deceleration correction is performed.
At this time, even if the overshoot of the U/Ub value causes it to be determined as an acceleration at part B in the figure, the deceleration timer 18 has already been set and is within its set time, so the acceleration correction circuit 14 is activated by the deceleration timer 18. don't work,
Therefore, acceleration correction is not performed.

The above operation is shown in a flowchart as shown in FIG.

That is, at 100, acceleration/deceleration is determined based on a change in the U/lJb value, and if it is determined that acceleration is occurring, then at 110, it is determined whether the count value of the deceleration timer is 0 (the set time has elapsed after cents). A judgment is made. If only YES, an acceleration correction is performed at 120 and an acceleration timer is set at 130.

If it is determined at 100 that the vehicle is decelerating, then at 140 it is determined whether or not the count value of the acceleration timer is O. Only if YES, at 150, a deceleration correction is made and at 160 a deceleration timer is set.

Incidentally, the acceleration timer and deceleration timer are decremented at regular intervals until they reach O after cent.

As explained above, according to the present invention, deceleration correction is not performed even if it is determined that deceleration has occurred for a certain period of time after acceleration correction, and acceleration correction is not performed even if it is determined that acceleration has occurred for a certain period of time after deceleration correction. Therefore, even if there is an erroneous determination of acceleration or deceleration due to an overshoot of the output signal of the air flow meter, correction is not performed based on the erroneous determination, thereby achieving the effect that appropriate correction can be performed.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional example of an air flow meter;
The figure is a diagram showing the overshoot of the output signal of the air flow meter during acceleration and deceleration, and Fig. 3 is a block diagram showing one embodiment of the electronically controlled fuel injection device by Honshamei.
FIG. 4 is a flowchart 1 to the main part of the same. 11... Ignition coil 12... Air flow meter 13... Basic pulse generation circuit 14... Acceleration correction circuit 15... Deceleration correction circuit 16... Drive circuit
17...Fuel injection valve 18...Deceleration timer for stopping the acceleration correction function 19...Acceleration timer for stopping the deceleration correction function Patent applicant Fujio Sasashima, Patent attorney, Japan Electronics Co., Ltd.

Claims (1)

[Claims] Electronic control of an internal combustion engine, comprising an acceleration correction means that detects a change in an output signal of an airflow make, determines acceleration, and corrects the fuel injection amount, and a deceleration correction means that similarly determines deceleration and corrects the fuel injection amount. In the fuel injection device, means for stopping the function of the deceleration correction means for a certain period of time after acceleration correction;
1. An acceleration/deceleration correction device for an electronically controlled fuel injection device for an internal combustion engine, comprising means for stopping an acceleration correction function for a certain period of time after deceleration correction.