JPH0232865Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an engine fuel supply device.

(Prior art) Conventionally, as an engine fuel supply system, a temperature detection means detects the fuel temperature, cooling water temperature, engine atmosphere temperature, etc. in the engine, and when the detected temperature is higher than a predetermined value, the engine is started. There is a known structure in which only the fuel pump is operated and cooled fuel is circulated from the fuel tank to the fuel system to eliminate vapor lock (for example, see Japanese Patent Laid-Open No. 57-65850).

(Problem to be solved by the invention) However, this type of conventional engine fuel supply system detects the temperature around the engine, such as the fuel temperature, and operates the fuel pump and valves, so it is necessary to use a temperature detection means. This requires additional equipment and operation control means, making the structure complex and difficult to manufacture. Also,
The problem was that the engine could not be operated for a while after the ignition switch was closed.

In addition, regarding a system in which a bubble storage chamber is provided on the upper wall of the intermediate portion of the fuel distribution pipe, and a valve provided in this bubble storage chamber is used to remove air bubbles when the engine temperature exceeds a set value, the applicant of the present application Jitsugan 1987-
It has already been filed in the earlier application No. 50212 (Utility Model Application No. 162266/1983).

The present invention has been developed in view of the above-mentioned conventional problems, and even if fuel containing bubbles flows into the fuel distribution pipe when the engine is hot, the present invention prevents the bubbles from flowing into the fuel injection valve. It can be removed efficiently,
Also, it is easy to manufacture, such as improving the core removal during casting.
The purpose is to provide a simple air bubble removal structure.

(Means for Solving the Problems) Means for achieving the above objects of the present invention are directed to a fuel supply system for an engine that includes a fuel distribution pipe that distributes fuel to a plurality of fuel injection valves. The fuel distribution pipe is formed so that its cross section gradually expands from one end to the other end,
It consists of a tube forming a fuel passage extending laterally. The upper wall of the tube gradually slopes upward from one end to the other, and the lower wall of the tube slopes approximately from one end to the other. extends horizontally. A fuel inlet is opened at the smaller end of the cross section, a fuel outlet is opened near the upper wall at the larger end of the cross section, and a fuel outlet is opened at the lower wall of the tube. It is assumed that a plurality of distribution ports are opened for distributing the fuel in the tube to each fuel injection valve.

(Function) As a result, in the present invention, even if fuel containing bubbles flows into the fuel distribution pipe from the fuel inlet at one end, the bubbles flow upwardly from the fuel inlet side to the outlet side. The fuel flows on the wall side along the upper wall, and is discharged together with the return fuel from a fuel outlet provided near the upper wall at the other end. At this time, since the fuel distribution port to each fuel injection valve is opened in the lower wall part which is far away from the upper wall part, it is difficult for air bubbles to flow into the fuel injection valve, and the fuel injection Air bubbles can be prevented from entering the valve.

Further, since the fuel distribution pipe is formed of a pipe whose cross section gradually expands from one end to the other, the fuel distribution pipe can be easily discontinued during casting, and manufacturing is facilitated.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 to 3, in the engine fuel supply system of this embodiment, each fuel injection valve 3 attached to the intake pipe 2 branched for each cylinder of the engine 1 is , is provided with a fuel distribution pipe 10 that distributes fuel by a fuel pipe 4 branched for each cylinder.

The fuel distribution pipe 10 has a cross section at one end 1
The tube body is formed so as to gradually widen from 1 to the other end 12, and forms a fuel passage extending in the lateral direction. Upper wall portion 1 of the fuel distribution pipe 10
3 is gradually inclined upward from one end 11 to the other end 12, and the lower wall 14 extends approximately horizontally from one end 11 to the other end 12. There is. A fuel inlet 11a is opened at the end 11 of the fuel distribution pipe 10 on the side with the smaller cross section, and the upper wall portion 13 of the end 12 on the side with the larger cross section is opened.
A fuel outlet 12b is opened nearby. Further, a plurality of distribution ports 14a, 14a, . . . for distributing fuel to each fuel injection valve 3 are opened in the lower wall portion 14 of the fuel distribution pipe 10. Further, a pressure regulator valve 7 as a pressure regulating means is connected to the fuel outlet 12b.

The fuel distribution pipe 10 is manufactured by aluminum casting using, for example, a tapered core having a cross-sectional shape as shown in FIG. A pipe joint 6a is attached to connect the fuel conduit 6, and a blind cover 15 is attached to a heat-resistant and oil-resistant packing 1 at the open end of the large diameter end 12 using a screw hole provided in a boss portion 12a around the open end.
6 and is secured liquid-tightly with bolts. Further, each distribution port 14a of the lower wall portion 14 has a fuel pipe 4 corresponding to each cylinder of the engine 1.
are connected by welding or the like.

Fuel such as gasoline is supplied to the fuel distribution pipe 10 from a fuel tank 8a via a filter 8c by a fuel pump 8b as shown by arrow A (see FIG. 1). Since the fuel distribution pipe 10 is located in the engine room, it gets heated by long-term engine operation, and when the engine is stopped and the fuel pump 8b is stopped, a so-called vapor lock occurs which makes it difficult to restart the fuel pump 8b. During this hot period, the bubbles that are generated are passed along the sloped upper wall 13 to the fuel outlet 1 at the top.
2b to the pressure regulator valve 7. The pressure regulator valve 7 is connected to a control pipe 7a that communicates with a surge tank 2a provided in the intake pipe system.
From the valve element 7b, which moves under the control of the intake pressure transmitted by By returning the pressure, the fuel pressure in the fuel distribution pipe 10 (for example, about 2.5 kg/cm ² when the engine is stopped) corresponding to the intake pressure (equal to atmospheric pressure when the engine is stopped) is adjusted.

(Effects of the invention) As described above, according to the engine fuel supply device of the invention, even if fuel containing bubbles flows into the fuel distribution pipe from the fuel inlet, the bubbles are removed from the fuel introduction side. The upper wall side inclined upward toward the outflow side is guided to the other end along the upper wall, and the fuel can be efficiently discharged along with the return fuel from the fuel outlet provided near the upper wall at the other end. can. Moreover, since the fuel distribution port to each fuel injector is opened in the lower wall part which is far away from the upper wall part, it is difficult for air bubbles to flow into the fuel injector. It is possible to prevent the air-fuel ratio from becoming lean due to fuel shortage by preventing the inflow of air bubbles.

Further, since the fuel distribution pipe is formed of a pipe body whose cross section gradually expands from one end to the other, it is easy to stop or remove the fuel distribution pipe during casting, and manufacturing can be facilitated.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of an engine fuel supply system of the present invention, FIG. 2 is a vertical sectional view of a fuel distribution pipe applied to the above embodiment, and FIG.
It is a sectional view taken along the - line in the figure. DESCRIPTION OF SYMBOLS 1... Engine, 3... Fuel injection valve, 7... Pressure regulator valve (pressure adjustment means), 10
... Fuel distribution pipe, 11 ... Small diameter end, 11a ...
Fuel inlet, 12... Large diameter end, 12b... Fuel outlet, 13... Upper wall, 14... Lower wall, 14
a... Distribution port.

Claims (1)

[Scope of Claim for Utility Model Registration] In an engine fuel supply device equipped with a fuel distribution pipe that distributes fuel to a plurality of fuel injection valves, the fuel distribution pipe has a cross section from one end to the other end. The tube body is formed to gradually expand across the length of the tube and forms a laterally extending fuel passage, and the upper wall portion of the tube body gradually expands upward from one end to the other end. The lower wall of the tube extends approximately horizontally from one end to the other, and a fuel inlet is opened at the end on the smaller side of the cross section. A fuel outlet is opened near the upper wall at the end of the larger cross section, and a plurality of holes are provided at the lower wall of the tube for distributing the fuel in the tube to each fuel injection valve. A fuel supply device for an engine, characterized in that a distribution port is opened.