JPS6232351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply system for an internal combustion engine that includes one feed cylinder and a plurality of cylinders communicating therewith.

In a conventional internal combustion engine equipped with one feed cylinder and a plurality of cylinders communicating with the feed cylinder, fuel is injected into each cylinder separately, resulting in a complicated and expensive fuel supply system. In order to improve this problem, it has been considered to inject fuel from one point downstream of the throttle valve in the feed cylinder and distribute it to each cylinder, but in this case, the direction of fuel injection is fixed, so it is difficult to inject fuel into each cylinder. Fuel distribution tends to become uneven, making smooth operation difficult. When fuel is supplied by such a fuel injection method, the amount of fuel injected is proportional to the signal from the air amount sensor that detects the intake air volume. Conventional air flow sensors include a method in which a rotary plate that rotates in proportion to the intake flow rate is installed in the intake passage and its rotation angle is detected, or a heating wire is placed inside the intake passage and the plate is cooled by the intake air flow. Methods such as detecting changes in the resistance of heating wires are used, but the signals from these air volume sensors are processed by an electronic processing device, and the output signal is used to inject a fuel amount proportional to the intake air volume. The air-fuel ratio is controlled by However, since the intake air amount signal in this case is proportional to the intake air volume, there is a drawback that an error occurs in the air-fuel ratio when the intake air temperature changes.

An object of the present invention is to provide a fuel supply device for an internal combustion engine that has a relatively simple configuration and is suitable for supplying a mixture having an even air-fuel ratio into multiple cylinders, and is characterized by the following: In a fuel supply system for an internal combustion engine having a plurality of cylinders communicating with one feed cylinder, a variable bench lily portion whose intake flow path cross-sectional area changes in proportion to the intake air amount is provided upstream of the throttle valve of the feed cylinder. , a signal of the cross-sectional area of the intake flow path obtained from the amount of movement of the suction piston of the variable bench lily, and a signal of the cross-sectional area of the intake flow path obtained from the amount of movement of the suction piston of the variable bench lily, are applied to the narrowest part of the variable bench lily. It is characterized in that a fuel injection part that intermittently performs forced injection opens in proportion to the amount of intake air determined from the negative pressure signal determined from the provided negative pressure detector.

FIG. 1 is a sectional view of a fuel supply system for an internal combustion engine, which is an embodiment of the present invention. Throttle valve 2 of feed cylinder 1
A suction chamber 3 is installed on the upstream side. A suction piston 5 moves while being guided by a guide hole 4 provided in the center of the suction chamber 3. In addition, a ventilation hole 6 is provided at the bottom of the suction chamber 3, and the suction piston 5,
Since the space 13 formed by the supply cylinder 1 and the suction chamber 3 communicates with the outside air, the suction piston 5 can easily move within the suction chamber 3. suction piston 5
A plurality of circumferential grooves are provided on the outermost surface of the
Air leakage between the suction chamber 3 and the inner wall surface of the suction chamber 3 is reduced. The outer surface of the cylinder 11 installed in the center of the suction piston 5 is connected to a linear ball bearing 10 attached to the suction chamber 3.
Since the suction piston 5 is brought into contact with the suction piston 5, the movement of the suction piston 5 is extremely smooth. In addition, since a compression spring 12 is installed between the suction chamber 3 and the suction piston 5, when the intake air does not flow into the bench lily portion 8, the suction piston 5 is pushed down to approach the inner wall of the supply cylinder. However, the groove 16 provided on the distal end surface of the suction piston 5 mainly forms an intake passage.

An air flow sensor 14 is installed in the upper part of the suction chamber 3, and the cylinder 11 can penetrate into the center hole of the air flow sensor 14. Further, a fully open switch 17 is installed at the shoulder of the suction chamber 3, and a contact rod 19 is installed at the top of the suction piston 5.
An idle switch 18 is installed on the upper surface of the feed cylinder 1 facing the contact rod 19. The airflow sensor 14 is a differential transformer that detects the position of the cylinder 11 (the cross-sectional area of the variable bench lily portion 8) and sends a signal to the data processing device 20. Further, the full open switch 17 and the idle switch 18 are micro switches,
A signal is sent to the data processing device 20 during high load operation when the suction piston 5 rises to the upper end and during idle operation when the suction piston 5 descends to the lower end. In other words, it is impossible for the carburetor of this structure to control the air-fuel ratio over a wide range of operating conditions at these extremes, resulting in a fuel supply shortage. In such a case, the configuration is such that the operation of the data processing device 20 is switched to increase the amount of supplied fuel to a suitable condition. A temperature sensor 21 is installed in the intake passage of the supply cylinder 1, and a negative pressure sensor 22 is installed in the variable bench lily portion 8.
This signal is also sent to the data processing device 20.

The data processing device 20 calculates the amount of intake air based on the signal of the cross-sectional area of the intake flow path of the variable bench lily portion 8 from the air flow sensor 14 and the negative pressure signal from the negative pressure sensor 22, and calculates the amount of intake air from the signal from the temperature sensor 21. The result of performing temperature correction on the intake air amount using the signal is supplied to the terminal 31 as an output signal. The amount of intake air subjected to the temperature correction is proportional to the weight of the intake air, and even if there is a temperature change, it is possible to always inject a suitable amount of fuel and send a mixture with a suitable air-fuel ratio to the engine.

The fuel injection part 30 is an outer cylinder 34 attached to the supply cylinder 1.
, an inner cylinder 33 installed within the outer cylinder 34 , and a fuel pipe 39 connected to the inner cylinder 33 . The upper end of the inner cylinder 33 opens into the narrowest part of the variable bench lily part 8, and a movable needle 32 and a compression spring 35 are housed therein. A filter cylinder 37 installed at the lower part of the inner cylinder 33 has a fuel passage hole at the center of the shaft, and a filter 38 is fixed to the lower part thereof. Further, a coil 36 connected to the terminal 31 is installed in the space between the outer cylinder 34 and the inner cylinder 33, and when current from the data processing device 20 flows through the coil 36, the needle 32 is pulled down to drain the fuel. The variable bench lily section 8 is made to inject.

The operation of the fuel supply device configured in this manner will be described below. When the opening degree of the throttle valve 2 of the intake cylinder 1 increases and the amount of intake air flowing into the variable bench lily portion 8 increases,
Negative pressure is generated in the communication hole 7 provided on the lower surface of the suction piston 5, compressing the compression spring 12 and raising the suction piston. At this time, negative pressure sensor 2
The negative pressure signal generated at 2, the intake air temperature signal from the temperature sensor 21, and the signal regarding the intake air passage cross-sectional area from the air flow sensor 14 are processed by the data processing device 20. Since the data processing device 20 supplies a current with a duty ratio proportional to the intake air weight to the coil 36, the time ratio for opening the upper end opening of the inner cylinder 33 increases, thereby increasing the amount of fuel injected into the variable vent lily portion 8. let Note that a fuel pump is provided in the fuel flow path connected to the fuel injection section 30 to apply a constant positive pressure to the fuel. The fuel injected into the variable bench lily portion 8 is further atomized by the rapid intake air flow flowing therethrough and is well mixed with the intake air, so that it is injected into the plurality of cylinders communicating downstream of the throttle valve 2. The mixture is distributed with a uniform air-fuel ratio.

Next, when the opening degree of the throttle valve 2 decreases, the flow velocity of the intake air passing through the variable bench lily section 8 decreases, so the negative pressure in the internal chamber 15 decreases and the pressure increases until it balances with the spring force of the compression spring 12. The piston 5 descends. Therefore, when the signal from the air sensor 14 changes, a duty ratio signal corresponding to the intake air amount at that time is given to the coil 36, and the variable bench lily section 8
Reduce the amount of fuel supplied to the In this way, the cross-sectional area of the intake flow path at the narrowest part of the variable bench lily part 8 changes in proportion to the intake air amount, so the intake flow rate of the variable bench lily part 8 is almost constant, and the fuel is transferred to the narrowest part where the intake flow velocity is greatest. Since the injected fuel is injected at the same time, even if the opening degree of the throttle valve 2 changes, the injected fuel is always mixed well and the uniformity of the air-fuel mixture does not change.

As a result of the above, the air-fuel ratio of the mixture supplied to the internal combustion engine is suitably controlled, and the opening degree of the throttle valve 2,
In other words, smooth operation is possible regardless of the operating condition, and the composition of the exhaust gas is purified. As mentioned above, the full open switch 17 and the idle switch 18 are used to prevent fuel dilution during high load operation or idling operation when the throttle valve is fully open.

As described above, the fuel supply device of this embodiment supplies a uniformly mixed air-fuel mixture with a suitable air-fuel ratio to multiple cylinders by injecting an amount of fuel proportional to the intake weight into the narrowest part of the variable bench lily part. This has the effect that it can be distributed and supplied to In addition, since the fuel injection part only needs to be installed at one location in the variable bench lily part of the feed cylinder, the structure is simple, and the output distribution circuit of the data processing device connected to it is also simple, which has the advantage of reducing the overall cost. ing.

The fuel supply system for an internal combustion engine according to the present invention has the effect of supplying a mixture having an even air-fuel ratio to a plurality of cylinders with a relatively simple configuration and enabling suitable operation.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fuel supply system for an internal combustion engine, which is an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Fuel cylinder, 2... Throttle valve, 8... Variable bench lily part, 21... Temperature sensor, 22... Negative pressure sensor, 30... Fuel injection part.

Claims (1)

[Claims] 1. In a fuel supply system for an internal combustion engine having a plurality of cylinders communicating with one feed cylinder, the cross-sectional area of the intake flow path changes in proportion to the amount of intake air upstream of the throttle valve of the feed cylinder. A variable bench lily section is provided, and a constant positive pressure is applied to the fuel at the narrowest part of the variable bench lily section, and the cross-sectional area of the intake flow path is determined from the amount of movement of the suction piston of the variable bench lily section. A fuel injection section that intermittently injects forcefully opens in proportion to the intake air amount obtained from the signal and the negative pressure signal obtained from the negative pressure detector provided in the variable bench lily section. Fuel supply system for internal combustion engines. 2. The fuel supply system for an internal combustion engine according to claim 1, wherein the fuel injection section is a fuel injection section that injects the fuel amount proportional to the intake air weight obtained by temperature-correcting the intake air amount.