JPS593132A - Fuel injection control device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To smooth rise of revolving speed during acceleration and enhance the operating characteristic by furnishing a throttle valve opening sensing means, which emits outputs proportional to the degree of opening of a throttle valve when it exceeds a certain specific value, and by making fuel increment corrective control in accordance with the valve opening by the use of the output given. CONSTITUTION:Stamping-in of an accelerator pedal 8 will rotate a throttle valve stem 4A through a wire 7, and when the angle of rotation attains a certain specific value, i.e. when the throttle valve 4 is opened to a certain specific value, a boss 15 fixed to the stem 4A comes in contact with a link 16 to allow the motion of the link 16 to be transmitted to a shaft 19 through links 17, 18, where a potentiometer 20 is mounted on the shaft 19. The potentiometer 20 gives signals proportional to the degree of opening when the throttle valve 4 opens exceeding a certain specific degree of opening, and this output signal is put in a control circuit 22. This control circuit 22 gives fuel injection valves 14A-14D a fuel increment corrective signal in accordance with the abovementioned degree-of-opening signal to allow the fuel to be injected in respective increased amounts to individual cylinders.

Description

[Detailed description of the invention] The present invention relates to a fuel injection control device for an internal combustion engine.

In general, internal combustion engines that electronically control fuel supply always obtain a mixture with an optimal air-fuel ratio to improve fuel efficiency and maintain good exhaust purification through catalysts. There is something like that shown in Figure 1.

Branches 5A, 5B, 5G, 5D of intake manifold 2
have fuel injection valves 14A, 14B, and 14G.

14D are attached to each. The intake air amount sensor 9 is interposed in the intake passage 3 upstream of the throttle valve 4 and detects the amount of intake air. The throttle valve 4 is configured to increase or decrease its opening via an accelerator wire 7 according to the degree of depression of the accelerator pedal 8, and a position detector 6 in the vicinity of all throttle valves is installed on the shaft 4A of the throttle valve 4. The position of the throttle valve 4 near the fully open position is detected and the state is turned to A. A negative terminal of the ignition coil 10 is connected to a control circuit 12 and outputs an engine speed signal. A water temperature sensor 11 is installed in the cylinder head 1 and detects the engine cooling water temperature. Note that 13 is an air cleaner.

The control circuit 12 controls the air-fuel ratio of the air-fuel mixture supplied to the engine (each cylinder) based on the intake air amount signal from the intake air amount sensor → No. 9 and the engine speed signal from the ignition coil 10. The basic fuel 1 injection (basic injection amount) is calculated so as to reach the target value, and then based on the signal from the water wetness sensor 11, the basic injection amount is corrected to increase when the temperature is low. From this corrected fuel injection amount, the fuel injection valves 14Δ, 14
B, 140. Determine the drive pulse width to 14D, and based on this pulse signal, fuel injection valves 14Δ, 14B.

14C and 14D supply fuel into each cylinder.

By the way, the control circuit 12 has a position detector 6 near all throttle valves.
Based on the signal from the engine, the fuel amount is increased at full load, thereby improving acceleration performance and output.

However, if the throttle valve 4 is in the vicinity of the fully open position and the throttle valve full position detector 6 detects this, the fuel injection amount is controlled to increase at a constant rate.
For example, when the air-fuel ratio is 18 or higher at partial load (rarely
) In a lean engine that operates with a mixture, there is a problem in which the air-fuel ratio suddenly becomes richer due to the increase correction at full load when transitioning from partial load to full load where the throttle valve is fully opened, resulting in poor operability. Ta.

The present invention is provided with a throttle valve opening detection means that generates an output proportional to the throttle valve opening at a predetermined opening of the throttle valve or more, and based on the detected value from this detection means, fuel is It is an object of the present invention to solve the above-mentioned problems by smoothly increasing and correcting the injection amount.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 shows an embodiment in which the present invention is applied to a four-cylinder engine, and the same components as in FIG. 1 are indicated by the same symbols.

First, to explain the configuration, here, the fuel injection valves 14A, 1
4B, 14C, 14D are directly attached to the cylinder head 1, but each branch 5A, 5B, 5C of the intake manifold 2 is attached as in the conventional example.

It may be attached to 5D.

20 is a potentiometer as a throttle valve opening detection means;
The throttle valve 4 is connected to the throttle valve 4 through a number of links 1 so that the output value increases in proportion to the throttle valve opening when the opening of the throttle valve 4 exceeds a predetermined opening.

Specifically, the link mechanism is configured as shown in FIG. 3A. 1. That is, the protrusion 15 is fixed to the shaft 4A of the throttle valve 4, and the link 16 is rotatably attached to the shaft 4A so as to be freely rotatable. This link 16 is connected via a link 17 to a link 18 fixed to a shaft 19. A potentiometer 20 is attached to this shaft 19.

Therefore, when the shaft 4Δ rotates as the opening degree of the throttle valve 4 increases, the protrusion 15 fixed to the shaft 4A pushes the link 16,
The shaft 19 is connected to this via a link 17°18.
rotates, and the potentiometer 20 attached to the shaft 19 rotates (see FIG. 3(B)).

At this time, the opening degree of the throttle valve is proportional to the degree of depression of the accelerator pedal 8 (Fig. 4 (A)).
The opening degree of the potentiometer 20 is approximately 80 degrees from fully open to fully open, and the operating amount starting point of the potentiometer 20 is approximately 40 degrees at the throttle valve opening, and the rotation angle of the potentiometer 20 is approximately 60 degrees from this point.
(Fig. 4 (B)). When the rotation angle is set in this way, the resistance value of the potentiometer 20 changes in proportion to the rotation angle. Figure 4 (C)
), when this is connected to the control circuit 22, the output of the potentiometer 20 becomes proportional to the throttle valve opening at a predetermined opening of the throttle valve 4 or more, as shown in FIG. 4 (D>).

The potentiometer 20 is attached to the shaft of the throttle valve of the secondary side throttle chamber in the twin-barrel type.

Reference numeral 21 denotes a crank angle sensor, which is attached to the distributor 1 to the heater, and generates a reference crank angle signal (180' signal) synchronized with the engine speed and a cylinder number discrimination signal (720° signal).

Further, 9 is an intake air amount sensor, 11 is a water humidity sensor, 13
is an air cleaner.

Reference numeral 22 denotes a control circuit, which will be explained based on the circuit configuration diagram in FIG.

The input signals to the control circuit 22 are classified into two types depending on the person. The first is the intake air amount signal from the intake air amount sensor 9, the output signal from the potentiometer 20, the engine cooling water temperature signal from the water wetness sensor 11, and the battery 33 (second
The second input signal is an analog value input signal such as a battery voltage signal from a C (not shown in the figure);
This is a pulse signal having a pulse train such as a reference crank angle signal (180° signal) and a cylinder number discrimination signal (720° signal) from the 21, and the analog value input signal is converted to a digital value before being processed. become.

The multiplexer 23 has a function of selecting only one signal from among various signals, and selects and outputs only the necessary signal from among the input signals.

The analog-to-digital converter (A/D converter) 24 converts an input signal of analog value into a signal of digital value and outputs the signal.

26 is a central processing unit l-<CPU) that performs digital arithmetic processing; 27 is a memory element (ROM) for storing control programs and fixed data; 28 is a readable and writable memory element (RAM); 25
is an input/output interface circuit (Ilo), and between these are a data bus 29, a control bus 30. They are communicated via address bus 31.

In addition, the input/output interface 71 chair circuit 25 is connected to the CPU 26
The fuel injection valves 14A and 1 use the inner signal as a fuel injection signal.
4B and 140.14D, respectively. Regarding the fuel injection signal, sequential control is performed by the CPU 26 in the order of #1-#3-#4-#2 cylinders (in the case of 4 cylinders) based on the cylinder number discrimination signal from the crank angle sensor 21. .

Next, the operation of this configuration will be explained based on the circuit diagram of FIG. 5 and the flowchart i- of FIG. 6.

During normal operation, a reference crank angle signal from the crank angle sensor 21 is input to the CPU 26 via the input/output interface circuit 25, and the CPU 26 calculates the engine speed based on this signal and reads it into a register within the CPU 25. Next, the intake air amount signal from the intake air amount sensor 9 is selected by the multiplexer 23, converted to a digital value by the A/D converter 24, and inputted to the CPU 26 via the input/output interface circuit 25. The CPU 26 reads this signal into the same register within the CPU 26 as the intake air amount. The CPU 26 calculates the intake air amount per engine revolution from the engine speed and intake air amount read in the register, calculates the basic fuel injection amount tJJ proportional to this value,
Write this into RAM28.

Next, the output signal from the potentiometer 2o is selected by the multiplexer 23, converted into a digital value by the A/D converter, and inputted to the CPU 26. Based on this signal, the CPU 26 calculates the m increase correction coefficient due to the throttle valve opening. (Fig. 4 (E)), the injection correction amount is calculated by multiplying the basic injection amount by this increase correction coefficient. After that, the engine cooling water temperature signal from the water temperature sensor 11 and the battery 3
The battery voltages from 3 are sequentially selected by the multiplexer 23 and read into the register of the CPU 26 as the water temperature and battery voltage via the A/D converter 24 and the input/output interface circuit 25. Based on these water temperature and battery voltage signals, the CPU 26 determines an increase correction coefficient based on the water temperature and battery voltage, and calculates the injection correction amount by multiplying the basic injection amount by this increase correction coefficient. Then, the CPU 26 adds the injection correction amount based on the basic injection amount to obtain the final fuel injection value, and from this, the fuel injection valves 14A, 14B.

The drive pulse width that determines the valve opening time of 140.14D is calculated, and a pulse signal (fuel injection signal) having this drive pulse width is output.

It goes without saying that in order to obtain the injection correction amount based on the throttle valve opening, it is possible to look up a table based on the engine speed and the throttle valve opening.

The fuel injection signal is applied to the fuel injection valves 14A, 14B, and 14G in the order of cylinders #1, #3, #4, and #2 according to the cylinder number discrimination signal from the crank angle sensor 21.

Reach 14D.

Therefore, based on the output signal from the potentiometer 20, the fuel injection amount is increased in proportion to the opening degree of the throttle valve 4 when the opening degree of the throttle valve 4 is higher than the predetermined opening degree. Compared to conventional equipment where the air-fuel ratio is poorly connected,
The air-fuel ratio is better connected because the fuel is increased smoothly.

As explained above, according to the present invention, the fuel injection amount is increased and corrected in proportion to the throttle valve PF 1 degree when the opening degree of the throttle valve is greater than or equal to a predetermined opening degree. Even so, the air-fuel ratio is better connected to the rich air-fuel ratio operation at all throttle valves, the rotational speed rises more smoothly during acceleration, and drivability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional example, FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 3(A). (B) is a diagram explaining the operation of the link mechanism connected to the shaft of the throttle valve, and Figure 4 (Diagram showing the relationship between the degree of depression of the accelerator pedal and the degree of opening of the throttle valve, Figure 4 (B)). (C ), (D), and (E) do not show the potentiometer rotation angle, potentiometer resistance value, potentiometer output j, and increase correction coefficient depending on the throttle valve opening, respectively, with respect to the throttle valve opening. The circuit configuration diagram and FIG. 6 are flowcharts 1 to 4. 4... Throttle valve, 4A, 19... Shaft, 14A, 14B. 14, C, 14D... Fuel injection valve, 15... ·protrusion,
16.17.18... Link, 20... Potentiometer, 21... Crank angle sensor, 22... Control circuit. Fig. 4 (A) Fig. 4 (B) Stock Seikan/L (・) Fig. 4 (C) Fig. 4 (D) Fig. 4 (E) Throttle valve @/l (・) Fig. 6

Claims (1)

[Claims] A means for detecting the intake air amount of the engine, a means for detecting the engine rotation speed, a circuit for calculating fuel injection (to) so as to obtain a predetermined air-fuel ratio based on these detected values, and a predetermined crankshaft from this circuit. In an internal combustion engine equipped with a fuel injection valve that operates based on a fuel injection pulse signal sent out every angle, a throttle valve opening detection means generates an output proportional to the throttle valve opening at a predetermined opening of the throttle valve or more. 1. A fuel injection control device for an internal combustion engine, wherein the fuel injection amount is increased and corrected in accordance with the detected value in a region where the throttle valve is opened to a predetermined degree or more.