JPS58214629A - Electronically controlled fuel injection device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To enhance the responsiveness of an engine upon acceleration, by obtaining a compensating value for an increase in fuel injection amount upon acceleration, in accordance with the open degree of a throttle valve, a variation in the open degree of the throttle valve and the rotational speed and temperature of the engine. CONSTITUTION:An increase amount compensating circuit 7 is connected with the output terminal of a throttle-opening sensor 10 of potentiometer type which issues an open degree signal S6 that varies continuously in accordance with the open degree of a throttle valve 11, and receives an ignition signal S1 from an ignition coil 2 and a temperature signal S7 from a cooling water temperature sensor 12. Further, the increase amount compensating circuit 7 calculates an increase amount rate K in accordance with the open degree alpha of the throttle valve 11 given through the throttle-opening sensor 10, the variation DELTAalpha of the open degree alpha, the rotational speed N of the engine and the temperature Tw of cooling water. Thereby, the responsiveness of the engine upon acceleration may be enhanced.

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 increasing the amount of fuel to be injected during acceleration.

Generally, an electronically controlled fuel injection system for an internal combustion engine drives an electromagnetic fuel injection valve at a predetermined timing once per engine rotation using a pulse signal with a pulse width based on the intake air amount. During acceleration, the fuel injection amount calculated based on the intake air amount is increased and corrected to improve responsiveness during acceleration.

However, in conventional electronically controlled fuel injection systems, an idle switch that is turned on when the throttle valve is fully open (idle state) is used to detect the acceleration state and make fuel increase corrections, and the idle switch is turned on when the throttle valve is fully open (idle state). Since the amount was increased at a fixed rate of increase only when the engine was accelerating from an idling state, the amount was not increased or not when the engine was accelerating from slow to sudden acceleration, or from a partial load. Even so, the problem was that it was not appropriate for the situation.

The present invention was made with the aim of solving such conventional problems, and it is possible to detect the throttle opening given by a throttle opening sensor that detects the opening of the throttle valve and the amount of change (rate of change) thereof. By providing an increase correction circuit that determines the increase rate at the time of increase correction based on the engine rotation speed and engine temperature, it is possible to obtain an appropriately corrected fuel injection amount in various situations. , with the aim of improving responsiveness, etc.

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

Referring to FIG. 1, the ignition signal S1 obtained from the ignition coil 2 of the engine 1 and the intake air amount detector 4 provided in the intake passage 3
The intake air amount signal S2 obtained from S2 is input to the fuel injection amount calculation circuit 6 of the control unit 5, and the fuel injection amount signal (basic pulse signal) 33 calculated by the calculation circuit 6 is inputted to the fuel injection amount calculation circuit 6 of the control unit 5.
is sent to the fuel injection valve drive circuit 8 via the increase correction circuit 7.

Here, outside the increase correction circuit, the fuel injection amount signal 53 (=34) calculated by the calculation circuit 6 is inputted as is to the drive circuit 8, and the drive circuit 8 receives fuel based on the input fuel injection amount signal S3. A drive pulse signal S5 for driving the injection valve 9 is formed and output to the fuel injection valve 9. From then on, it is the same as before.

The output end of a throttle opening sensor 10 is connected to the increase correction circuit 7, and the throttle opening sensor 10 is of a potentiometer type and outputs an opening signal s6 that continuously changes depending on the opening of the throttle valve 11. It is something to do.

In addition, the increase correction circuit 7 receives an ignition signal S1 from the ignition coil 2 and a temperature signal s7 from a temperature sensor 12 that detects the temperature of the cooling water of the engine 1.

The increase correction circuit 7 calculates the throttle opening α given by the throttle opening sensor 10, the amount of change Δα in the opening α, and the engine speed N based on the ignition signal from the ignition coil 2.
and the cooling water temperature Tw given by the temperature sensor 12, the increase rate K is calculated.

The calculation here is to calculate 1-f (α, Δα) from the throttle opening degree α and the amount of change Δα to a predetermined increase rate using a map, and then from the rotation speed N to the predetermined increase rate as shown in Figure 2. 2 is determined, and 3 is determined from the increase rate determined as shown in FIG. 3 from the temperature Tw. Then, add + and 2 to these increase rates.
The product of 3 (KC = + ・K2・K3) is determined as the increase rate.

Here, K=f(α, Δα, N, T+1). Note that t is the elapsed time.

By doing so, the optimum increase rate K can be determined in the increase correction circuit 7 during acceleration from the throttle opening α, its variation Δα, the rotational speed N, and the temperature Tw, and thereby the increase correction circuit 7 can calculate the optimum increase rate K. The circuit 7 converts the fuel injection amount signal S3 calculated by the calculation circuit 6 into a signal S4 having a pulse width of (1+K) Pv4, where the pulse width of the signal S3 is Pu. to increase the injection amount from the fuel injection valve 9.

Therefore, it is possible to perform increase correction corresponding to various situations such as slow acceleration to sudden acceleration or acceleration from partial load, and the response is excellent.

Further, as shown in FIG. 4, in the hatched area where Δα is large, the responsiveness can be further improved by performing interrupt injection between predetermined injection timings, in addition to the above-mentioned increase correction. The earliest interrupt injection at this time is f (α,
N).

It goes without saying that the value of 1 is set to 0 except during acceleration, so that the increase rate K is set to 0.

As explained above, according to the present invention, the fuel increase rate during acceleration is determined from the throttle opening, the amount of change thereof, the engine speed, and the temperature. Correction becomes possible, and drivability etc. can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an electronically controlled fuel injection system showing an embodiment of the present invention, and FIGS. 2 to 4 are various diagrams used in calculating the fuel increase rate in the embodiment. 1... Engine 2... Ignition coil 4... Intake air amount detector 6... Arithmetic circuit 7... Increase correction circuit 8... Drive circuit 9... Fuel injection valve 1
o...Throttle opening sensor 11...Throttle valve 12...Temperature sensor Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima

Claims (1)

[Claims] In an electronically controlled fuel injection system for an internal combustion engine, which determines the fuel injection amount according to the intake air amount of the engine and increases the fuel injection amount during acceleration, a throttle opening sensor that detects the opening of the throttle valve is used. An internal combustion engine characterized by being provided with an increase correction circuit that determines an increase rate at the time of increase correction based on a given throttle opening, the amount of change in the opening, engine speed, and engine temperature. Electronically controlled fuel injection device.