JPS5832931A - Electronic fuel injection device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent mixed gas in the early stage of the accerelation of an engine from being excessively concentrated by providing a correction amount operating circuit additionally performing correction for reducing an injection amount by a prescribed amount for a prescribed period in the early accerelation stage of the engine. CONSTITUTION:A basic injection amount signal Tp is computed from an air intake amount Qa and the number of revolution of an engine Ne. In order to correct this basic injection amount signal Tp according to the operating parameter of the engine, a hybrid correction amount operating circuit 22 is provided. The basis injection amount signal Tp is corrected in a multiplying circuit 23, according to the engine operating parameter, driving an electromagnetic fuel injection valve 5. In the circuit 22, correction for reducing the injection amount by a prescribed amount for a prescribed period in the engine accerelation early stage is additionally performed. In this way, mixed gas can be prevented from being excessively concentrated in the early acceleration stage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electronic fuel injection device for an internal combustion engine, in particular an internal combustion engine equipped with a three-way catalyst for exhaust gas purification, which calculates the basic injection amount of fuel from the engine speed and intake air amount. The present invention relates to an electronic fuel injection device that corrects this basic injection amount according to operating parameters of the electronic fuel injection device.

In an internal combustion engine equipped with such an electronic fuel injection device, when the engine is accelerated, the fuel-air mixture temporarily becomes excessively rich, and during acceleration during 10-mode driving, unburned components HC and CO are released. was found to be emitted in large quantities. The amount of unburned components emitted increases by ζ'2 when the throttle valve in the intake passage is opened from fully open for acceleration.

The present invention reduces the fuel injection amount for a predetermined period of time at the beginning of acceleration in order to prevent the mixture from being too rich at the beginning of acceleration. This reduction in injection amount does not require a rich mixture (at complete warm-up, for example, when the engine cooling water temperature is 70°C or higher and
It is best to do this when the rotation is 000 rpm.

The invention will be explained and explained below with reference to the drawings.

In FIG. 1, air is taken into an internal combustion engine 1 via an air cleaner 2 and an intake manifold 3. As shown in FIG. The amount of intake air is changed by the throttle valve 4. Intake manifold 3
The electromagnetic fuel injection valve 5, which is installed in each branch pipe of the fuel injection valve and injects fuel, is controlled by a control device when it is opened.・The exhaust manifold 6 is provided with a three-way catalyst 16 for purifying exhaust gas. In order to set the basic injection amount of fuel, the intake air amount signal from the air fluorometer 7 and the signal from the primary winding terminal 13 of the ignition coil 12 (hereinafter referred to as rotation speed cm) connected to the power distributor 11 are used. The rotation speed signal is transmitted to the control device 14
given to.

The output signal of the oxygen sensor 8 provided in the exhaust manifold 6 is also given to the control device 14, and feedback control is performed so that the actual air-fuel ratio becomes the stoichiometric air-fuel ratio. Furthermore, in order to correct the injection amount, an intake air temperature sensor 10 is located in the intake passage upstream of the air flow meter, and a throttle valve opening sensor 15 is located at the throttle valve 4 and includes an idle switch that is closed when the throttle valve is fully open. , and the output signal of the water temperature sensor 9 located at the cooling water jacket are provided to the control device 14.

FIG. 2 shows an outline of the injection amount control device 14, in which the signal Qa from the air flow meter 7 and the signal N from the rotation speed sensor 13 are shown.
e is given to the basic injection amount calculation circuit 21, and the basic injection amount signal Tp=M·Qa/Ne (K is the proportional constant and the stoichiometric air-fuel ratio) is calculated. In order to correct this basic injection amount according to engine operating parameters, a hybrid correction amount calculation circuit 22 is provided, and sensors 7 , 8 , 9 , 10
, 15 and the basic injection amount signal Tp are provided, and the output signal VF of this circuit 22 is provided as an analog signal to a correction multiplication circuit 23. The output signals of the temperature sensors 9 and 10 are also supplied to this multiplication circuit 23. The basic injection amount signal Tp is corrected in this multiplication circuit 23 according to the engine operating parameters and is given to the engine 5 as a drive signal Ti.

FIG. 3 shows FIG. 2 in a little more detail, and corresponding parts are given the same reference numerals. In this case, the output signal pulse of the rotation speed sensor 13 is frequency-divided by a frequency dividing circuit 25 and then given to the basic injection amount calculation circuit 21 . The hybrid correction amount calculation circuit 22 includes a central processing unit (CPU) 27, a synchronization clock pulse generator 28, an interrupt control unit 29, and a digital input capacitor connected to each other via a bus 26.
30, a digital output port 31, a random access memory (RAM) 32, a read-only memory (ROM-to-digital converter 34, and a digital-to-analog converter 35), and the basic injection amount signal Tp is supplied to the interrupt control section 29. The digital controller 30 includes an oxygen sensor 8, a throttle valve opening sensor 15 including an eye switch, a starting sensor 36, and a clutch sensor 3.
The converter 34 is supplied with an output signal 7, and the converter 34 is also connected to an air flow meter 7 and a water temperature sensor 7. 9 output signals are provided.

Now, in order to prevent the mixture from becoming too rich at the beginning of Karen,
After acceleration, the fuel injection amount is reduced to 2 for a predetermined period of time, for example, 4 revolutions of the engine.
Decreased by 0%. This reduction shall only be useful during full warm-up, when a rich mixture is not required. This warm-up condition is that the engine cooling water temperature is 70°C or higher and the temperature is 2000℃ after starting.
Take the rotation progress. When the throttle valve 4' is opened from the fully closed state in order to accelerate the fully warmed-up engine, the idle switch ≠ in the throttle valve opening sensor 15 opens at time to as shown in FIG. 4(b). (Step 101 in Figure 5).

Here, the water temperature is 70℃ or higher (stage lO°2) and the temperature is 20℃ after starting.
00 revolutions (step 103), in other words, if the engine is completely warmed up, if the engine speed is within 3 revolutions (rev) after the idle compensation switch is opened (step 104), then (step 104) of FIG. As shown in a), the injection quantity is reduced by 20% (step 105). After this 2096 reduction in the injection amount continues, for example, for 3 rotations, the reduction is canceled and the injection amount is returned to the original amount. However, if the injection amount is suddenly returned to, the shock will be large, so for example, the 4th rotation.
As shown in (a) of the figure, the amount decreases by 596 per rotation.

is decreased and the injection amount is returned to the original injection amount (reduction amount 096) in stages. This prevents the air-fuel mixture from becoming too rich during acceleration, and also reduces the torque fluctuation when the injection amount returns to the original amount by canceling the decrease in the injection amount, thereby preventing deterioration in driving performance. If the rotation is within 8 rotations after 3 rotations after opening the idle switch (step 106), a stepwise reduction amount related to the rotation speed between 20% and θ'% is set (step 107). These processes are performed by the central processing unit 27 of the correction amount calculation circuit 22 based on the output signal of the idle switch in the throttle valve opening ↓ sensor 15.

Now, the output signal of the converter 35 of the correction amount calculation circuit 22 is sent to the correction multiplier circuit 22 as an analog injection amount correction signal VF.
and is multiplied by the basic injection amount signal Tp provided via the backflow prevention diode 41 to correct the injection amount. The correction multiplication circuit 23 is also supplied with signals from the water temperature sensor 9 and the intake air temperature sensor 10. Note that the fuel cutoff signal Fc from the digital output port 31 is also given to the correction multiplier circuit 23 . The output signal of the multiplier circuit 23 is the drive signal 1゛! The output signal from the OR circuit 42 is sent to the OR circuit 42 along with the asynchronous injection signal As from the digital output capo 31.
Transistor 450 connected to power supply 44 via
It is applied to the base to operate the injection valve 5 four times. Note that the correction multiplier circuit 23 is connected to a power source 44 via a pull-up resistor 46.

Thus, according to the present invention, by temporarily reducing the injection amount when accelerating from a fully closed throttle valve when there is no need to warm up, it is possible to prevent the air-fuel mixture from becoming ``over-rich'' at the beginning of acceleration. -c7., Unburned components in the exhaust gas "7" can be reduced.

Furthermore, by canceling the reduction and returning to the original injection amount in stages, it is possible to reduce torque changes and maintain desired driving performance. Furthermore, these processes can be electrically and easily performed by the hybrid correction amount calculation circuit.

In the above description, opening and closing of the idle switch is used to detect acceleration, but changes in the intake air amount by an air flow meter or changes in intake pressure by an intake pressure sensor can also be used.

Furthermore, in order to cancel the injection amount reduction during racing that requires a rich mixture, it is also possible to determine whether or not this cancellation can be done based on the rotational speed in centimeters.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an electronic fuel injection device for an internal combustion engine, Fig. 2 is a schematic block diagram of an injection amount control device, Fig. 3 is a block diagram mainly showing details of the correction amount calculation circuit of the control device, and Fig. 4 5 is a diagram illustrating the effect of reducing the injection amount, and FIG. 5 is a flowchart of control. l... Internal combustion engine, 5... Electromagnetic fuel injection valve, 7...
Air flow meter, 13... Rotation speed sensor, 15...
Throttle valve opening sensor

Claims (1)

[Claims] The basic injection amount of fuel is calculated from the engine speed and intake air amount, and this basic injection amount is corrected according to the operating parameters of the engine. Electronic fuel injection device for an internal combustion engine, characterized in that it additionally performs a decreasing correction.