JPS62288336A - Fuel supply device for internal combustion engine - Google Patents

Abstract

PURPOSE:To eliminate the fuel supply delay at acceleration and improve the stability of combustion, by providing an injection valve upstream a collecting portion of an intake manifold and also providing an acceleration fuel supply hole opening into an intake port in each cylinder. CONSTITUTION:A fuel injection valve 5 is provided in a throttle body 2 upstream a collecting portion 3 of an intake manifold. An acceleration fuel passage 10 is branched from a fuel supply passage 7 communicated to the injection valve 5, and outlet passages 10A of the acceleration fuel passage 10 are provided at intake ports 12 in cylinders. A solenoid valve 14 is provided on the way of the acceleration fuel passage 10. The solenoid valve 14 is controlled to be opened only at acceleration to thereby increase a fuel. Accordingly, the fuel supply delay at acceleration and the reduction in fuel distribution to each cylinder may be prevented, thereby properly controlling an air-fuel ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply system for an internal combustion engine, and more particularly to a system for increasing the amount of fuel supplied auxiliary when the engine accelerates.

(Prior Art) A device generally called an acceleration pump is known as a device for increasing the amount of fuel supplied when an internal combustion engine accelerates. For example, Utility Model Publication No. 61-4885, No. 46
As disclosed in Publication No. 86, etc., accelerating fuel is basically sucked and discharged through a diaphragm type accelerator pump that responds to the throttle valve opening. '? In other words, the diaphragm 7 performs a fuel suction action based on the strong intake pipe negative pressure generated downstream of the throttle valve during low-load operation.
During acceleration, the increased amount of fuel is injected into the intake pipe by taking advantage of the decrease in intake pipe negative pressure caused by the increase in the opening of the throttle valve and causing the rediaer 7 ram to perform a discharge operation using spring force.

(Problems to be Solved by the Invention) However, according to these conventional fuel supply devices, accelerating fuel is supplied upstream of the gathering part of the intake branch pipes, so In this case, the distribution of accelerating fuel to each 'A cylinder is likely to be uneven, and it takes about 7 hours for the fuel to actually reach the combustion chamber after it is supplied, and some of the accelerating fuel may leak onto the intake pipe wall on the way. As a result, the air-fuel ratio of the air-fuel mixture does not necessarily follow changes in operating conditions appropriately, which tends to cause poor acceleration and suffocation.

This problem is caused by the so-called lean burn engine 1. In the second case, the air-fuel ratio is very large at steady state and low load, so even if the acceleration fuel is supplied in the above manner at the beginning of sudden acceleration, the mixture becomes too lean. The flammability deteriorates dramatically.

Is the present invention a fuel supply device that solves these conventional problems? The purpose is to provide /.

(Means for solving problem 1.'') In the present invention,
Using a fuel supply device with a fuel injection valve installed upstream of the collecting part of the intake pipe as a fuel, the acceleration fuel passage is pumped from the fuel injection resistant fuel injection valve supply passage described in I'+ij, and the outlet thereof is The side passage portion is branched into a plurality of parts so as to face the intake ports of each cylinder of the engine, and a valve means for regulating the measurement is interposed in the middle of the acceleration fuel passage.

(Function) Based on the two-leg configuration, by opening the acceleration fuel passage through the valve means during acceleration, the fuel fJ to the fuel injection valve (fuel is introduced from the fuel supply passage to the acceleration fuel passage.This acceleration fuel is directly supplied to the combustion chamber of each cylinder via the outlet side passage facing the intake port of each cylinder.

Therefore, there is no delay in the supply of acceleration fuel or poor distribution.
An appropriate air-fuel mixture is generated that corresponds to the increase in required load.

In addition, in a steady state of operation where the supply of acceleration fuel is not required, the supply of acceleration fuel is stopped by cutting off the acceleration fuel passage through the nut means (Example 4). ) Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

In FIG. 1, reference numeral 1 indicates a tournament-type intake branch pipe suitable for an in-line four-cylinder engine, and reference numeral 2 indicates a throttle body provided upstream of a gathering portion 3 of the intake branch pipe 1.

The throttle body 2 is provided with an electromagnetic fuel injection valve 5 located on the upstream side of the intake throttle valve 4, and the injected fuel from the fuel injection valve 5 is delivered to each cylinder through the intake branch pipe 2 along with the intake air. distributed and supplied to.

Pressurized fuel from a fuel pump 6 is supplied to the fuel injection valve 5 via a fuel supply passage 7, and excess fuel is supplied to the fuel pump 6 via a fuel return passage 9 in which a pressure regulator 8 is interposed. It is returned to the suction side. This fuel circuit makes the pressure of fuel supplied to the fuel injection valve 5 constant. The fuel injection amount is controlled by changing the valve opening time ratio of the -ζ fuel injection valve 5 via a control circuit (not shown) under the constant fuel pressure.

The fuel circuit to the fuel injection valve 5 also serves as a fuel source for increasing the amount of fuel during acceleration, and an acceleration fuel passage 10 is branched from the middle of the fuel supply passage 7.

The acceleration fuel passage 10 has #1. #2 cylinder group and #3. It branches in two directions toward the cylinder group of #4 cylinder or C), and further branches into the outlet side passage section 1()8 which connects to the intake port 12 of each cylinder via the check valve 11 and connects to the DH port. ing. In this case, the check fr-11 is the second branch lA of the tournament type inhalation 1 cough fF1 (convergence part: 3 is the 1st instigation part, and the part that branches toward each genus on the downstream side) When fuel pressure is applied from the acceleration fuel passage 10 on the upstream side, the valve opens to allow fuel to pass to the outlet side passage 10A.

Note that an orifice 13 is provided in the middle of the outlet passage 10A to adjust the fuel flow rate at this time to an appropriate amount.

Furthermore, in the middle of the acceleration fuel passage 10, an electromagnetic valve 14 is interposed as a valve means for regulating the fuel flow rate, located on the 2nd part side of the branches 1.2 to the above-mentioned cylinder groups. There is.

This electromagnetic valve #t, 4 is of an on/off type, and in response to a drive signal from the control circuit 15 described below, the valve opens when energization is on, and closes when energization is off.

The control circuit 15 determines the acceleration state of the engine based on the change in degree tJIf of the throttle valve 4 detected via the throttle angle sensor 16, and controls the on/off state of the solenoid valve 14.

In other words, by differentiating the opening degree of the throttle valve 4 and finding its rate of change,
When this force C is equal to or greater than a predetermined reference value, it is determined that the accelerating state is present, and the electromagnetic valve 14 is energized, and when the force is other than J■, the energization is stopped. Furthermore, the energization time varies depending on the acceleration state, and the larger the rate of change in the opening degree of the throttle valve 4 is, the greater the acceleration request is identified, and the energization time to the solenoid valve 14 is determined.

Now, the control circuit 1G determines that it is in an acceleration state and turns the electromagnetic switch R-14 to li! When the valve is turned on, a portion of the pressurized fuel from the fuel pump 6 is transferred from the fuel supply passage 7 to the acceleration fuel passage until the solenoid valve 14 is closed again as the energization time determined as described above elapses. Enter 1()・\,
Further, push open the check valve 11 and open the 71 D side passage section 1.
( ) A is injected toward the intake port 12 of the three cylinders. As a result, the amount of accelerating fuel corresponding to the acceleration state is directly supplied to the intake port 12 and the engine combustion chamber, so even if the engine is at J5 during sudden acceleration, acceleration can be achieved without delay in fuel supply or deterioration of fuel distribution. Ensure suitable rich mixture @
The fuel is fed into the combustion chamber, and therefore, even in a lean burn engine, excellent acceleration power and drivability are exhibited without causing suffocation or poor combustion during acceleration.

Figure 2 shows changes in the engine operating state due to the supply of acceleration fuel in comparison with the conventional example.
L = load・load) divided by 1 air-fuel ratio (A/l”
) is set on the lean side, conventionally, as shown by the broken line, there is stiffness as shown by the dashed line, and when accelerating, there is a delay in fuel supply even though the air flow rate increases by 4. The air-fuel ratio fluctuated excessively toward the lean side, resulting in misfires and poor combustion, resulting in engine torque fluctuations and other problems that significantly deteriorated driveability and acceleration. On the other hand, the 45 cup according to the present invention is made as described above. Since acceleration fuel is supplied directly to the f cylinder, a mixture with an appropriate air-fuel ratio can be generated during the acceleration process and supplied in a responsive manner, resulting in excellent engine performance. It is.

On the other hand, in FIG. 1, when the energization to the solenoid valve 14 is stopped, the acceleration fuel passage 10 is closed, and at the same time, the outlet side passage part 1
Since the check valve 11 located at the base end of 0A is also closed,
There is no possibility that excess fuel will leak out under operating conditions other than acceleration, including when the engine is stopped.Furthermore, the acceleration fuel passage 10 between the check valve 11 and the solenoid valve 14 is provided with:
Since a certain amount of pressure remains when each is at rest,
Acceleration fuel can be promptly supplied for the next acceleration.

In addition, in the present invention, the configuration of the control system is relatively simple because the accelerating fuel is measured mechanically, and whether or not the accelerating fuel is supplied is controlled by a valve means composed of a solenoid valve or the like. For example, the cost required for development work such as matching is significantly lower than that in which correction is performed by program control so that the amount of fuel injected via the electromagnetic fuel injection valve 5 increases during acceleration, and therefore the equipment cost is reduced. It has the advantage that it can be made lower.

(Effects of the Invention) As described above, according to the present invention, the accelerating fuel introduced from the pressurized fuel passage of the fuel injection system during engine acceleration is directly transmitted through the accelerating fuel passage opened through the engine intake port. Since the fuel is supplied to the engine combustion chamber, it is possible to avoid delays in fuel supply, adhesion to the intake pipe, and deterioration of distribution between cylinders.
A mixture with an appropriate accelerating air-fuel ratio can always be supplied to the engine.

Therefore, excellent acceleration force and drivability can be ensured especially in lean burn engines.

Furthermore, since the fuel increase control during acceleration is relatively simple in the present invention, there is an advantage that the device cost can be reduced compared to a system in which the fuel injection amount is increased and corrected by electronic control.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. fjS2 is a timing chart for explaining its operation and effect in comparison with a conventional example. 1... Intake branch pipe, 2... Throttle body, :(
...Intake branch pipe gathering part, 4...throttle valve, 5...
Fuel injection valve, 6...Fuel pump, 7...Fuel supply passage, 8...Pressure regulator, 9...Fuel return passage, 1()...Acceleration fuel passage, IOA...Acceleration fuel Exit side passage section of passage, 11... Check valve, 12
...Suction port, 13...17th port, 14.
... Solenoid valve, 15... Control circuit, 16... Throttle angle sensor.

Claims (1)

[Claims] In a fuel supply system in which a fuel injection valve is provided upstream of a collection point of intake branch pipes, an acceleration fuel passage is branched from a fuel supply passage to the fuel injection valve, and the outlet side passage is used as an intake passage for each cylinder of the engine. 1. A fuel supply device for an internal combustion engine, characterized in that the acceleration fuel passage is branched into a plurality of passages facing a port, and a valve means for regulating the opening degree of the acceleration fuel passage is interposed in the middle of the acceleration fuel passage.