JPH0124373Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fuel tank immersion type fuel pump installed in an internal combustion engine such as an automobile, and more particularly to a device for removing vapor generated within a pump case.

The mounting structure and internal structure of a conventional fuel pump of this type will be explained based on FIGS. 1 and 2. A fuel pump 1 is provided at the bottom of a fuel tank 2 and immersed in fuel. When the engine (not shown) is in operation, a turbine 4 rotationally driven by a motor 3 sucks fuel in the fuel tank 2 through an intake port 6 through a strainer 5, and discharges it from an upper end discharge port 7 to generate fuel. The fuel is pumped through the tube 8 from above the fuel tank 2 to the demand section. Further, surplus fuel is returned into the fuel tank 2 via the return tube 9. Incidentally, a float portion of a float type fuel gauge is attached integrally with the fuel pump 1.

By the way, in such a fuel pump 1, the pump case 10 is filled with vapor generated in the discharge side fuel passage at the time of a hot restart of the engine, and the pump suction performance is significantly reduced, and in the worst case, fuel suction may not be possible. Since this is possible, a vapor extraction hole 10a is opened to prevent this.

However, in the conventional structure in which the vapor vent hole 10a is simply provided, fuel leaks from the vapor vent hole 10a when the fuel pump 1 is operated, resulting in a problem that the pump suction performance is reduced. was.

The present invention was devised in view of these conventional problems, and an object of the present invention is to provide a vapor removal device for a fuel tank immersion type fuel pump that allows vapor removal without reducing pump efficiency. .

For this reason, in the present invention, a vapor removal passage is provided in the part of the pump case facing the fuel discharge side, and the passage is kept open by the fluid resistance when the vapor generated inside the pump case passes. The above objective is achieved by providing an on-off valve that is set to a closing force that closes due to the fluid resistance when passing through.

The present invention will be explained below based on illustrated embodiments. FIG. 3 shows the internal structure of a fuel pump equipped with a vapor removal device according to the present invention, and FIG. 4 shows an enlarged view of the vapor removal device.
However, in this embodiment, the same components as in FIG. 2 will be described with the same reference numerals. In the figure, the bottom wall of the pump case 10 housing the motor 3 and the turbine 4 driven by the motor 3 is closed except for the suction port 6, and the vapor removal device is located on the side of the pump case 10 facing the discharge side of the turbine 4. provided.

That is, in FIG. 4, a vapor vent hole 10b is formed penetrating through a part of the side wall of the pump case 10, and a cylindrical portion 10c is integrally formed so as to protrude outward concentrically with the vapor vent hole 10b. .

The inner wall of the cylindrical portion 10c is a valve body 11 which will be described later.
The seat surface 10d of the valve seat 12 when the valve is opened and the seat surface 10 of the valve seat 12
e. Inside the cylindrical portion 10c are a valve body 11, a valve seat 12, and a spring 1 that is fitted between these and urges the valve body 11 in the valve opening direction.
3, and a stopper 14 whose outer peripheral edge is engaged and fixed in a groove formed in the inner peripheral wall of the cylindrical portion 10c with the valve seat 12 in pressure contact with the seat surface 10e.

Further, a vapor extraction hole 1 is provided in the inner wall of the cylindrical portion 10c.
A groove 10f communicating with the valve seat 1 is provided.
2 and the stopper 14 have 12a and 1 in the center, respectively.
4a can be provided. When the fuel pump 1' is not in operation, the valve body 11 is held in pressure contact with the seat surface 10d by the biasing force of the spring 13, and at this time, the pump Although the inside and outside of case 10 are connected,
When the fuel pump 1' is in operation, when vapor passes through, the fluid resistance of the vapor against the valve body 11 is
The biasing force of the spring 13 is larger, and the valve body 11
is held in pressure contact with the seat surface 10d, but when the liquid fuel tries to pass through, the fluid resistance of the fuel causes the spring 1
The valve body 11 overcomes the urging force of the spring 13
is compressed and pressed against the seat surface of the valve seat 12,
The hole 12a is closed to block communication between the inside and outside of the pump case 10.

Also, once the valve closes, fluid resistance disappears, but
In this case, the fuel discharge pressure inside the pump case acts on the valve body 11, which overcomes the biasing force of the spring 13 and holds the valve body 11 in pressure contact with the valve seat 12.

With this configuration, even if vapor is generated in the discharge passage when the fuel pump 1' is not in operation, such as during the summer, this vapor will be removed through the vapor vent hole 10b and the groove that communicate between the inside and outside of the pump case 10, as described above. 10f, and are efficiently discharged outside the pump case 10 through the holes 12a and 14a.
Further, when the fuel pump 1' is operated in this state, fuel can be smoothly sucked in and discharged, and deterioration of pump suction performance due to vapor can be prevented.

Furthermore, when the fuel pump 1' is in operation, when the vapor runs out, the valve body 11 is seated on the valve seat 12 due to the fuel discharge pressure, and communication between the inside and outside of the pump case 10 is cut off, thereby preventing fuel leakage from the vapor release passage. This can actively improve pump suction performance.

As explained above, according to the present invention, when the fuel pump is in operation, an on-off valve that closes due to the fluid resistance of the liquid fuel is provided in the vapor removal passage, so that the same vapor removal function as in the past improves the pump suction performance due to vapor. In addition to preventing fuel leakage during pump operation, it is possible to actively improve pump suction performance.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the mounting structure of a conventional fuel tank immersion type fuel pump, Fig. 2 is a sectional view showing the same structure of the same fuel pump, and Fig. 3 is a vapor removal device according to an embodiment of the present invention. FIG. 4 is a sectional view showing an enlarged portion of the vapor removal device of the same pump. 1'...Fuel pump, 2...Fuel tank, 10
...Pump case, 10b...Vapor vent hole,
10f...Groove, 11...Valve body, 12a, 14a...
...hole.

Claims (1)

[Scope of utility model registration request] In a vapor removal device for a fuel pump that is installed immersed in a fuel tank, a vapor removal passage is provided that communicates the inside and outside of a pump case facing the fuel discharge side, and the vapor removal passage is opened due to the fluid resistance of the vapor. A vapor removal device for a fuel tank immersion type fuel pump, characterized in that an on-off valve is provided with an intervening spring whose opening force is set so as to close due to the fluid resistance of liquid fuel.