JPS601363A - Carburetor for supercharged engine - Google Patents

Abstract

PURPOSE:To have pressure inside a cylinder balanced as well as to prevent fuel from leaking, by installing a seal part using an elastic body in two spots, top and bottom, of a push rod in an accelerator pump, while making supercharging pressure act on the intermediate part. CONSTITUTION:An accelerator pump 1 is attached to the side of a charging cylinder 11 of a carburetor, while a piston 2 is housed inside its cylinder 3. Now, when stepping on an accelerator pedal, a shaft 5 and a lever 6 are rotated and this rotation is transmitted to a rod 7 and a lever 8 and thereby the piston 2 is pressed downward so that pressure in fuel 4 goes up, pushing a weight upward, thus the fuel is spouted into the charging cylinder 11 from an injector nozzle 10. In the above constitution, a bellows type seal member 12 and an annular seal member 13 directly contacting a push rod 15 are installed in two spots, top and bottom, of this push rod 15, through which an air passage 14 is made to interconnect the intermediate part, thereby making supercharging pressure act thereon, thus a fuel leakage is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a carburetor for a supercharged engine, and particularly to an improvement in means for preventing fuel leakage from a piston-type accelerator pump.

[Background of the invention]

Generally, as described in JP-A-51-102736, a rubber bellows is used as a sealing member when the entire accelerator pump is installed in a carburetor, but this sealing member only uses the elasticity of the material itself. Therefore, it is difficult to prevent fuel leakage when a supercharger is provided upstream of the carburetor. That is,
In a piston-type accelerator pump, the bushing rod that operates the piston is exposed to the outside, and the bushing rod is moved in the axial direction, so it is difficult to prevent leakage.

[Purpose of the invention]

The present invention improves the drawbacks of conventional piston-type accelerator pumps,
It is an object of the present invention to provide a carburetor for a supercharged engine equipped with an acceleration pump that can maintain airtightness sufficiently even against supercharging pressure.

[Summary of the invention]

A feature of the present invention is that a seal portion using an elastic body is provided at two locations above and below the bushing rod of the acceleration pump, and the boost pressure is applied to the intermediate portion thereof.

[Embodiments of the invention]

FIG. 1 is a vertical sectional view of a carburetor for a supercharged engine, which is an embodiment of the present invention. An acceleration pump 1 is attached to the side surface of a feed cylinder 11 of the carburetor, and a piston 2 is housed in a cavity of the cylinder 3. By depressing the accelerator pedal of the car, the throttle shaft 5 and connecting lever 6 of the carburetor are rotated, and this movement is transmitted to the pump rod 7 and pump lever 8, and the piston 2
is pushed down, the pressure of the fuel 4 increases, pushing up the weight 9 and injecting it from the injector nozzle 10 into the feed cylinder 11.

On the other hand, when the supercharger operates upstream of this carburetor, the fuel 4 in the cylinder 3 is transferred to the push rod 1 due to its supercharging pressure.
It leaks to the outside through the surrounding area of 5.

Leaking the fuel 4 to the outside in this way may cause a fire or have other serious negative consequences. In order to prevent this, in this embodiment, the bushing rod 1
A bellows-type seal member 12 and an annular seal member 13 that directly contact the bushing rod 15 are provided at two locations above and below the bushing rod 15, and an air passage 14 is communicated between the two to apply supercharging pressure to prevent fuel leakage. The structure is designed to prevent this.

That is, the boost pressure is applied to the bellows type seal member 12 inside the cylinder 3.
However, it also acts on the inside of the sealing member 12.13 via the air passage 14, so that the internal and external pressures are equal. Therefore, the sealing member 12 is not deformed, and the pressure for pushing the fuel 4 to the outside is offset, so that no leakage occurs. A sealing member 13 installed above the bushing rod 15 prevents the supercharging pressure transmitted from the air passage 14 from leaking to the outside, and furthermore, in the event that the sealing member 12 is damaged, the pressure inside the cylinder 3 is directly connected to the sealing member 13. This prevents the fuel 4 from leaking outside due to contact.

The reason why the bellows-type seal member 12 is employed is that it is used as a means to reduce the number of sliding parts in order to operate the bush rod 15 as smoothly as possible.

FIG. 2 is an explanatory diagram of a method of mounting the sealing member 12 of the acceleration pump shown in FIG. 1, and shows an enlarged view of the member accommodated in the cylinder 3 of FIG. 1. The upper end of the sealing member 12 is fixed to the main body by a press-fit bushing 16, and the lower end thereof is a bushing slot.

It is sandwiched and fixed by a distance piece 17 inserted into the spring holder 15 and a spring holder 18. The inner thickness of the lower end of the seal member 12 is thicker than the 111° gap dimension of 14J1 between the distance piece 17 and the spring holder 18, so that the inner thickness of the lower end of the seal member 12 is larger than the 111° gap dimension of 14J1 between the distance piece 17 and the spring holder 18. It is made of wood.

The carburetor for a supercharged engine according to this embodiment is provided with two seal members on the top and bottom of the bushing rod, and supercharging pressure is applied between the seal members, thereby balancing the pressure inside the cylinder 3 and fueling the cylinder 3. It has a structure that prevents leakage. Further, since the bellows-type seal member 12 is fixed using the set load of the spring 190 of the piston 2, it is possible to obtain a simple and inexpensive fuel leak prevention structure.

〔Effect of the invention〕

The carburetor for a supercharged engine according to the present invention has a structure that can sufficiently maintain elegance against supercharging pressure, so that fuel leakage can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a carburetor for a supercharged engine according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a method of installing a seal member of the accelerator pump shown in FIG. 1. 1... Acceleration pump, 2... Piston, 3... Cylinder, 4... Fuel, 5... Throttle shaft, 6
...Connecting lever, 7...Pump rod,
8...Pump lever, 9...Weight, 10...
Injector nozzle, 11... Feed cylinder, 12... Seal member (bellows type), 13... Seal member, 14...
・Air passage, 15... Butsch rod, 17... Distance piece, 18... Funeral figure 7

Claims (1)

[Scope of Claims] 1. In a carburetor for a supercharged engine having a piston-type acceleration pump, a seal portion using an elastic body is provided at two locations above and below the bushing rod of the acceleration pump, and a seal portion using an elastic body is provided at an intermediate portion thereof. A carburetor for an engine with a supercharger, characterized in that it is configured to apply supply pressure. 2. The sealing member has one of the upper and lower sides as a bellows-type sealing member to reduce friction with the bushing rod,
The carburetor for a supercharged engine according to claim 1, wherein the carburetor is an airtight retaining part installed using a set load of a damper spring of a piston.