JPS58220931A - Electronic control system fuel injection device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent worsening of exhaust properties during deceleration, by deciding a correcting rate of the reduction in a quantity of the fuel jetted during deceleration based on the degree of opening of a throttle valve, the quantity of a change in the degree of opening, and the number of revolutions of an engine. CONSTITUTION:A reduction correcting circuit 6 computes a reducing rate K from the degree alpha of opening of a throttle detected by a throttle opening sensor 9, the quantity of a change DELTAalpha in said degree alpha of opening, and the number of revolutions N of an engine based on a rotary pulse from a rotary pulse generating circuit 1. This computation finds a predetermined reducing rate K1 from the degree alpha of opening of a throttle and the quantity of the change DELTAalpha and an increasing rate K2 from the number of revolutions N. The product K(=K1.K2) of the reducing rates K1 and K2 is decided as the reducing rate. Further, provided the pulse width of a basic pulse is PW, the reduction correcting circuit 6 converts the basic pulse which is passing a fuel cut circuit 4, into a fuel jet pulse having the pulse width of (1-K).PW, and feeds it to a drive circuit 7 to reduce the quantity of jet from a fuel jet valve 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically controlled fuel injection system for an internal combustion engine, and more particularly to a system for reducing and correcting the amount of fuel injection during deceleration.

Electronically controlled fuel injection systems for internal combustion engines generally drive an electromagnetic fuel injection valve at a predetermined timing once per engine rotation using a pulse signal with a pulse width based on the amount of intake air to correspond to the amount of intake air. However, during deceleration, the fuel was cut to improve fuel efficiency.

However, in conventional electronically controlled fuel injection systems, the deceleration state is detected using an idle switch that is turned on when the throttle valve is fully closed (idle state).
During deceleration as shown by the solid line in FIG. 1(A), the idle switch does not work and fuel cut is not performed. As a result, there is a problem in that the air-fuel ratio temporarily becomes rich as shown in FIG. 1(B) due to a delay in response, and the exhaust characteristics deteriorate. Incidentally, since fuel is cut during deceleration as shown by the broken line in FIG. 1(A), the exhaust characteristics do not deteriorate.

The present invention has been made with the aim of solving such conventional problems, and the amount of fuel injection is corrected to be reduced in accordance with various deceleration conditions, and the reduction rate at that time is determined by adjusting the opening of the throttle valve. By installing a reduction correction circuit that determines the throttle opening given by the throttle opening sensor that calculates the throttle opening, the amount of change (rate of change), and the engine speed, the By obtaining the corrected furnace injection amount, an appropriate air-fuel ratio is maintained, and deterioration of exhaust characteristics is prevented.

Hereinafter, the present invention will be described based on an illustrated embodiment.

In FIG. 2, ``■'' is a rotation pulse generating circuit, to which an ignition signal obtained from 1&(ill) of an ignition coil (-U in the figure) is supplied.

A basic pulse generating circuit 2 is connected to the output end of the rotational pulse generating circuit 1, and the basic pulse generating circuit 2 is connected to an intake air flow meter 3 provided in an intake pipe (not shown). The output end is also connected separately. A fuel cut circuit 4 is connected to the output end of the basic pulse generation circuit 2.
There is ζ. The output terminal of the U rotation pulse generation circuit 1 is connected to the fuel cup 1 circuit 4, and the output terminal of the idle switch 5 is also connected to it. This switch is turned on when the is fully closed. A drive circuit 7 is connected to the output end of the fuel cut circuit 4 via a weight loss correction circuit 6, which will be described later. An electromagnetic fuel injection valve 8 is connected to the output end of the drive circuit 7 .

In this manner, the ignition signal is waveform-shaped by the rotational pulse generation circuit 1, and is supplied to the basic pulse generation circuit 2 as a rotational pulse for each revolution of the engine synchronized with ignition. In response to this rotational pulse and the output voltage of the intake air amount measuring device 3, the basic pulse generating circuit 2 generates a basic pulse corresponding to the basic injection amount.

The fuel cut circuit 4 is a basic pulse reduction correction circuit in order to stop the fuel supply to the engine when the engine rotation speed caused by the rotation pulse is higher than a predetermined rotation speed (for example, 1640 rpm) and only one idle switch 5' is in the on state. Block passage to 6. Then, when the engine speed falls below a predetermined speed (for example, It 00 rpm), a basic pulse is passed to the reduction correction circuit 6 to supply fuel again even if the idle switch 5 is in the ON state. The basic pulse that has passed through the fuel cuff circuit 5, except for the reduction correction circuit, passes through the reduction correction circuit 6 as it is and becomes a fuel injection pulse. The drive circuit 7 drives the fuel injection valve 8 in response to the fuel injection pulse thus generated.

The reduction correction circuit 6 changes the fuel power/soto circuit 5 according to the deceleration situation.
The basic pulse that has passed is corrected to reduce the amount and is output to the drive circuit 7, to which the output end of the throttle opening sensor 9 is connected. The throttle/nottle opening sensor 9 is of the potentiometer type and generates an output voltage that continuously changes in accordance with the opening of the throttle valve. In addition, the output end of the rotation pulse generation circuit 1 is connected to the reduction correction circuit 6.

The reduction correction circuit 6 calculates the throttle opening α given by the throttle opening sensor 9, the amount of change Δα in the opening α,
The reduction rate K is calculated based on the rotational speed N of the engine based on the rotational pulse from the rotational pulse generation circuit 1.

The calculation here is to calculate +=f (α, Δα) for the throttle opening α and the amount of change Δα, and the predetermined reduction rate using the MA knob as shown in Figure 3, and from the rotation speed N as shown in Figure 4. Find 2 for the increase rate determined as shown.

And these weight loss rates K1. The product of 2 K (= + K
2) is determined as the weight loss rate.

Here, K=f(α, Δα, N,, t).

Note that t is the elapsed time.

By doing this, during deceleration in the reduction correction circuit 6, the throttle opening degree α and its change amount Δα,
The optimal weight loss rate K can be determined from the rotational speed N, and the weight loss correction circuit 6 uses the basic pulse that passed through the -5 fuel cut circuit 4 to have a basic pulse width of P-. At this time, the fuel injection pulse is converted into a fuel injection pulse having a pulse width of (l-K)·Pll, and sent to the drive circuit 7 to reduce the amount of injection from the fuel injection valve 8.

Therefore, it is possible to perform reduction correction corresponding to various deceleration situations such as deceleration from full load to partial load, maintain an appropriate air-fuel ratio, and prevent deterioration of exhaust characteristics during deceleration.

It goes without saying that the value of 1 is set to 0 except during deceleration, so that the weight loss rate K becomes 0. Then, during acceleration, another increase correction circuit may be provided to increase the fuel injection amount according to the acceleration situation.

Further, in this embodiment, the idle switch 5 and the fuel cut circuit 4 are provided separately, but since the weight loss correction circuit 6 can be provided with these functions, they can be omitted.

As explained above, according to the present invention, the reduction rate during deceleration is determined from the throttle opening, the amount of change thereof, and the engine speed, and the reduction correction is performed in accordance with various deceleration conditions. , it is possible to maintain an appropriate air-fuel ratio and prevent deterioration of exhaust characteristics during deceleration.

[Brief explanation of the drawing]

Fig. 1 4t' (A) (B) is a diagram for explaining the drawbacks of the conventional technology, Fig. 2 is a schematic diagram of an electronically controlled fuel injection system showing an embodiment of the present invention, Figs. The figures are various diagrams used in calculating the weight loss rate in the above embodiment. l...Rotational pulse generation circuit' 2...Basic pulse generation circuit 3...Intake air amount measuring device 6...Reduction correction circuit 7...Drive circuit 8...Fuel injection valve 9...・Throttle opening sensor patent applicant Japan Electronics Co., Ltd. Patent attorney Fujio Sasashima

Claims (1)

[Claims] In an electronically controlled fuel injection system for an internal combustion engine that determines the fuel injection amount according to the intake air amount of the engine, the fuel injection amount is corrected to decrease when the engine decelerates, and the reduction rate at the time of the reduction correction is adjusted to the throttle valve. Electronically controlled fuel for an internal combustion engine, characterized in that it is provided with a reduction correction circuit that determines the throttle opening given by a throttle opening sensor that detects the opening, the amount of change in the opening, and the engine rotational speed. Injection device.