JPS5815725A - Electronically controlled fuel injection device of internal combustion engine - Google Patents

Abstract

PURPOSE:To imporve torque of an engine and reduce its fuel consumption, by performing excess fuel correction in accordance with a function value corresponding to speed of the engine, when the opening of a throttle valve is at least a prescribed opening, and always obtaining output mixture ratio. CONSTITUTION:A throttle opening sensor 5 is connected to an excess fuel signal generator circuit 8, and an ignition signal is fed to said circuit 8. The excess fuel signal generator circuit 8 is previously stored with a function value corresponding to a frequency of the ignition signal in a memory or the like. In a range of large opening of a throttle valve, a built-in switch of the throttle opening sensor 5 is turned on, and the excess fuel signal generator circuit 8 generates an excess fuel signal of function value corresponding to the ignition signal. An excess fuel correction circuit 4 corrects pulse width of a basic pulse and generates a fuel injection pulse to obtain output mixture ratio. In this way, torque of an engine can be improved to reduce fuel consumption.

Description

[Detailed description of the invention] The present invention relates to an electronically controlled fuel injection system for an internal combustion engine.

An electronically controlled fuel injection system for an internal combustion engine calculates a fuel injection pulse with a pulse width based on various engine parameters so that the engine always performs proper combustion, and uses the fuel injection pulse to drive an electromagnetic injection valve to inject the fuel into the engine. It supplies fuel intermittently.

A conventional example of such an electronically controlled fuel injection device will be explained with reference to FIG.

In FIG. 1, reference numeral 1 denotes a rotation pulse generating circuit, to which an ignition signal obtained from the L side of an ignition coil (not shown) is supplied.

The output of the rotational pulse generation circuit 1 is the basic pulse generation circuit 2.
is connected to the basic pulse generating circuit 2, and the intake pipe (
The output of an air flow meter 3 provided in the air conditioner (not shown) is also connected separately. An increase correction circuit 4 is connected to the output of the basic pulse generation circuit 2. Connected to the increase correction circuit 4 are various sensors that command correction of the pulse width of the basic pulse according to engine parameters. The throttle opening sensor 5 instructs to increase the amount of fuel when the opening of one of the throttle valves exceeds a predetermined opening, and a built-in switch is turned on when the opening exceeds the predetermined opening. A drive circuit 7 for driving an electromagnetic injection valve 6 is connected to the output of the increase correction circuit 4 .

In the electronically controlled fuel injection system having the above configuration, the ignition signal is waveform-shaped and frequency-divided 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. On the other hand, the air flow meter 3 generates a voltage according to the amount of intake air. The basic pulse generation circuit 2 generates a basic pulse corresponding to the basic injection amount according to the output voltage of the air flow meter 3 and the rotation pulse, and the basic pulse is output from a sensor such as the throttle opening sensor 5 by the increase correction circuit 4. The pulse width is corrected according to the signal and becomes a fuel injection pulse. The fuel injection pulse thus generated drives the electromagnetic injection valve 6 via the drive circuit 7.

In such a conventional electronically controlled fuel injection system, the mixture ratio is controlled so that exhaust gas characteristics are good in a relatively small throttle valve opening range, but in a large throttle valve opening range, that is, in a high load, high speed range. In this case, a fixed amount of fuel increase is corrected based on the increase command from the throttle opening sensor 5, and control is performed to maintain the output mixture ratio.

However, in a region where the throttle valve opening degree is large for fuel increase correction, the pressure change of the intake air, so-called intake pulsation, is large, and the air flow meter 3 is affected by the intake pulsation and may not be able to accurately measure the amount of intake air. in this case,
Since the basic pulse width, that is, the basic injection amount fluctuates, it is difficult to maintain the output mixture ratio at all times with a fixed amount of fuel increase correction as described above.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electronically controlled fuel injection system which can always maintain an output mixture ratio in a large throttle valve opening range where fuel increase correction is performed.

The electronically controlled fuel injection device according to the present invention always maintains the output mixture ratio by increasing the amount of fuel according to a function value corresponding to the engine speed when the throttle valve opening is equal to or higher than a predetermined opening. be.

Hereinafter, embodiments of the present invention will be described with reference to FIG.

In FIG. 2, an increase signal generating circuit 8 is connected to the output of the throttle opening sensor 5. An ignition signal is supplied to the increase signal generation circuit 8, and the output of the increase signal generation circuit 8 is connected to the increase correction circuit 4.

In the increase signal generation circuit 8, a function value corresponding to the frequency of the ignition signal is stored in advance in a memory or the like. The rest of the structure of the electronically controlled fuel injection system according to the present invention having the above structure is the same as that of the conventional example shown in FIG. 1, so the explanation thereof will be omitted here.

In the electronically controlled fuel injection device according to the present invention having the above configuration, first, the basic pulse corresponding to the basic injection amount is generated by the basic pulse generating circuit 2 in accordance with the rotational pulse generated by the rotational pulse generating circuit 1 and the output voltage of the air flow meter. Occurs in In a region where the throttle valve opening is relatively small, the pulse width of the basic pulse is corrected in the increase correction circuit 4 according to the cooling water temperature, intake air temperature, etc., and becomes a fuel injection pulse that improves exhaust gas characteristics.

In a region where the throttle valve opening is large, the built-in switch of the throttle opening sensor 5 is turned on.

The increase signal generation circuit 8 detects an increase command due to the on state of this switch and generates an increase signal having a function value corresponding to the ignition signal. The increase correction circuit 4 corrects the pulse width of the basic pulse in response to this increase signal and the output signal of the water temperature sensor, etc., and generates a fuel injection pulse that achieves the output mixture ratio.

Note that the function value corresponding to the frequency of the ignition signal is a value that is approximately determined from the relationship between the intake pulsation of the internal combustion engine and the engine speed.

As described above, according to the electronically controlled fuel injection device according to the present invention, when the opening degree of the throttle valve is equal to or higher than a predetermined value, the amount of fuel is increased according to the function value corresponding to the engine speed. The output mixture ratio can be maintained at all times without being affected by intake pulsation in a large region. Therefore, engine torque can be improved and fuel consumption can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional example of an electronically controlled fuel injection device, and FIG. 2 is a block diagram showing an embodiment of the electronically controlled fuel injection device of the present invention. Explanation of symbols of main parts 1... Rotating pulse generation circuit 2...
...Basic pulse generation circuit 3...Air flow meter 4...Increase correction circuit 5...Throttle opening sensor 8...・・・
...Increase signal generation circuit Applicant: Japan Electronics Co., Ltd. Agent: Motohiko Fujimura, patent attorney

Claims (1)

[Claims] basic pulse generating means for generating a basic pulse according to engine speed and intake air amount; increasing correction means for generating a fuel injection pulse by correcting the pulse width of the basic pulse according to various engine parameters; a driving means for driving the electromagnetic injection valve according to the fuel injection pulse, and the increase correction means controls the basic pulse according to a function value corresponding to the engine speed when the opening degree of the throttle valve is greater than or equal to a predetermined opening degree. An electronically controlled fuel injection device for an internal combustion engine, characterized in that it performs correction.