JPH0579394A - Electronic control fuel injection device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to supply an electronic fuel injection device that bypasses a throttle valve and supplies fuel commensurate with intake air supplied to an engine. [Structure] A sensor that directly or indirectly detects an intake air amount, a control unit that smoothes a signal from the sensor to determine a fuel injection amount, and a throttle valve is bypassed to control an air amount supplied to an engine. It is composed of a device and reduces the smoothing of the signal from the sensor when the amount of air supplied from the device suddenly changes. [Effect] In order to determine the fuel injection amount by the air amount signal close to the intake air supplied to the engine by bypassing the throttle valve,
There is no excess or deficiency in fuel supply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for an internal combustion engine, and more particularly to a fuel injection device for an internal combustion engine having means for supplying intake air to the engine by bypassing a throttle valve.

[0002]

2. Description of the Related Art A control device for an internal combustion engine directly or indirectly detects the amount of air taken in by the engine, determines a fuel amount commensurate with the amount of air, and injects the fuel to supply the fuel to the engine. On the other hand, the amount of air taken in is detected by the sensor, but the output signal from the sensor must include noise due to the usage environment of the sensor and the characteristics of the single unit. In order to avoid this, the true intake air amount obtained by smoothing the input signal is performed.

Further, when the intake air amount changes abruptly due to the operation of the throttle valve, in order to prevent detection delay of the intake air amount due to smoothing, when the speed of movement of the throttle valve is a predetermined value or more, Used to reduce the degree of smoothing.

[0004]

In the above-mentioned prior art, since the degree of smoothing processing is changed depending on the speed of movement of the throttle valve, a rapid change in intake air amount without movement of the throttle valve is satisfactory. No degree of smoothing could be obtained.

Therefore, the present invention is to provide an electronic fuel injection device which is capable of favorably smoothing the intake air amount even when the intake air amount changes rapidly without the movement of the throttle valve.

[0006]

In order to achieve the above object, a state in which the intake air amount changes in addition to the movement of the throttle valve is detected, and the degree of smoothing the intake air amount is changed. Is.

[0007]

[Function] Since the state where the intake air amount changes other than the movement of the throttle valve is detected and the degree of smoothing the intake air amount is changed, it is possible to always inject and supply the fuel corresponding to the actual intake air amount.
No excess or deficiency of fuel supply.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel injection control device for an internal combustion engine according to the present invention will be described in detail below with reference to the illustrated embodiments.

FIG. 2 shows an example of an engine system applied to the present invention. In the figure, the air to be taken in by the engine is taken in from an inlet 2 of an air cleaner 1 and a throttle valve for controlling the intake flow rate is housed. Throttle valve body 5
Pass through and enter collector 6. Then, the intake air is distributed to each intake pipe 8 connected to each cylinder of the engine 7 and guided into the cylinder.

On the other hand, fuel such as gasoline is sucked and pressurized by a fuel pump 10 from a fuel tank 9, and then a fuel damper 11, a fuel filter 12, a fuel injection valve (injector) 13, and a fuel pressure regulator 14 are connected to a pipe. Is supplied to the fuel system being operated. Then, this fuel is regulated to a constant pressure by the above fuel pressure regulator 14,
Fuel is injected into the intake pipe 8 from a fuel injection valve 13 provided in the intake pipe 8 of each cylinder.

The air flow meter 3 outputs a signal representing the intake air flow rate, which is input to the control unit 15.

Further, a throttle sensor 18 for detecting the opening of the throttle valve 5 is attached to the throttle valve body 5, and its output is also input to the control unit 15. Next, 16 is a distributor (distributor), which has a built-in crank angle sensor, and which has a reference angle signal REF indicating the rotational position of the crankshaft.
And an angle signal POS for detecting the rotation speed (rotation speed), and these signals are also input to the control unit 15.

Reference numeral 20 is an O ₂ sensor provided in the exhaust pipe,
In order to detect the stoichiometric air-fuel ratio, it is detected whether the stoichiometric air-fuel ratio is rich or thin, and this output signal is also input to the control unit 15.

As shown in FIG. 3, the main part of the control unit 15 takes in signals from various sensors for detecting the operating states of the MPU, ROM and A / D converter engine as input, and performs predetermined arithmetic processing. The control signal is executed, various control signals calculated as the result of this calculation are output, and a predetermined control signal is supplied to the fuel injection valve 13 and the ignition coil 17 that have risen to perform fuel supply amount control and ignition timing control. Of.

Here, the signal from the air flow meter 3 is input to the control unit 15 and then passes through a smoothing circuit composed of a resistor and a capacitor, and then converted into an analog signal to a digital signal for use in arithmetic processing. ..

At this stage, noise removal in the signal is not sufficient under most operating conditions only by smoothing by the smoothing circuit, and further smoothing is performed in the arithmetic processing.

The smoothing method is, for example,

[0018]

[Equation 1]

Here, Qa: Intake air amount used for fuel injection amount calculation Qaold: Intake air amount determined in the previous calculation Qanew: Intake air amount obtained in this A / D conversion a: Determined by operating conditions The smoothing weighting factor is given. This smoothing process does not have to be used especially for the intake air amount, and may be applied to any parameter (basic fuel injection pulse width, etc.) until the fuel injection amount is determined.

Here, the larger the value of a, the greater the effect of smoothing, but the slower the response to the change in the intake air amount.

Therefore, the output signal of the throttle sensor 18 is input, and when the throttle valve 5 is suddenly operated, it is detected,
During a period in which a sudden change in the intake air amount will occur, the value of a is reduced and a value close to the actual intake air amount is used in the fuel injection amount calculation process.

Further, as an operating condition in which the intake air amount changes rapidly without operating the throttle valve 5, the idle speed control valve 22 may bypass the throttle valve 5 and suddenly change the air supplied to the engine 7. Can be mentioned.

Idle speed control valve 22
The function of the engine 7 is to secure the idling rotation of the engine 7 when the throttle valve 5 is at the minimum opening, that is, at the time of idling.

One system having the engine 7, for example, an automobile has a device that operates by using the power of the engine 7. Taking an automobile as an example, this device is an air conditioner, power steering, power generation by an alternator, or the like.

These devices normally operate even when the engine 7 is idle, and the engine 7 for supplying power to these devices needs to take in air commensurate with its generation of power. Yes, this air is supplied to the engine 7 through the idle speed control valve 22.
To ensure idling rotation.

Further, an electric load such as an air conditioner, a power steering, and a headlight for generating power of an alternator is usually operated in an ON / OFF step, and the idling speed is not changed at the time of switching. Therefore, the idle speed control valve 22 also operates in a stepwise manner by changing the output signal from the control unit 15 in a stepwise manner, and at this time, the intake air amount suddenly changes. Therefore,
According to the present invention, when the control unit 15 operates the idle speed control valve 22 in a stepwise manner and during a predetermined time thereafter, the value of a of the equation 1 is made smaller than the normal time and the intake air amount close to the actual intake air amount. By using the value of the amount for the calculation of the fuel injection amount, it is possible to supply the fuel suitable for the operating state of the engine 7.

FIG. 4 shows an embodiment of the present invention and a case where the present invention is not used, in which the air conditioner is turned on and off during idling.
The behavior when FF is performed is shown. According to the present invention, the air-fuel ratio is almost constant, whereas when the present invention is not used, the air-fuel ratio may not be constant for a certain period after ON and OFF. I understand.

In the above embodiment, when the idle speed control valve 22 is operated stepwise, it is used as a trigger for switching the value of a of the equation 1, but the stepwise operation is the operation state of each load. Control unit 15
Since the switching of the signal input to is performed as a trigger, the same result can be obtained even when the switching of the load signal is directly used as the trigger for switching the value of a.

Devices other than the idle speed control valve 22 are conceivable as devices for bypassing the throttle valve 5 and supplying air to the engine. However, by switching the value of a when these devices operate. Also has the same effect.

Further, in the above-mentioned embodiment, the predetermined time is given as the period for making the value of a of the equation 1 smaller than the normal time.
In addition, the same result can be obtained even if the engine crankshaft is rotated a predetermined number of times or the intake air amount is calculated.

Further, the same effect can be obtained by the time when the change amount of the intake air amount per time becomes equal to or less than the predetermined value, without particularly fixing the fixed period.

In this embodiment, the case of using the sensor for directly detecting the intake air amount has been described. However, in the method of indirectly detecting the intake air amount from the pressure of the intake pipe, the pressure of the intake pipe is detected. The present invention is also effective when the smoothing is performed in any of the processes from the signal to the determination of the fuel injection amount.

[0033]

According to the present invention, the amount of fuel commensurate with the amount of air supplied to the engine can be supplied by bypassing the throttle valve, so that neither excess nor deficiency of fuel will occur.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of the present invention.

FIG. 3 is a diagram showing an embodiment of the present invention.

FIG. 4 is a diagram showing the behavior of an embodiment of the present invention and a case where the present invention is not used when the air conditioner is ON and OFF.

[Explanation of Codes] 3 ... Air flow sensor, 5 ... Throttle valve, 7 ... Engine, 22
… Idle speed control valve.

Claims (1)

[Claims] 1. An internal combustion engine having means for supplying intake air to an internal combustion engine by bypassing a throttle valve, and determining a fuel injection amount based on a signal from a sensor that directly or indirectly detects the intake air amount. In the electronically controlled fuel injection device, the fuel injection amount is determined by a signal from a sensor that directly or indirectly detects the intake air amount when the intake air amount changes by bypassing the throttle valve and for a predetermined period thereafter. An electronically controlled fuel injection device for an internal combustion engine, characterized in that the smoothing process performed up to that time is changed when the amount of air taken in by bypassing the throttle valve does not change.