JPH066931B2 - Fuel pump unit - Google Patents

Description

The present invention relates to a fuel pump unit, in which a fuel pump is installed and a sub-tank provided in the fuel tank is hermetically sealed so as to have a negative pressure due to internal air suction. A first cut-off valve is provided to replenish the fuel from the fuel tank to the sub-tank by suction, and to close the valve opening as the fuel level in the sub-tank rises. Inside the fuel tank, the second cut-off valve is reversed. A first check valve is provided that is connected to an external second suction tube with a stop valve inserted between them, connects the first and second suction tubes to an evaporation tube that communicates with the engine, and stops gas from the evaporation tube side. A canister having a special configuration in which the inserted first tube is provided and a second check valve for stopping gas from the canister side is inserted into the second tube to communicate with the evaporation tube. Provided, even when the fuel in the new car or the like is not supplied to the sub tank, in which a configuration capable of replenishing the fuel sub-tank from the fuel tank to the negative pressure inside the empty automatically subtank by the air starting the engine.

(Prior Art) There is no fuel pump unit that uses a closed sub-tank that allows negative pressure in the air inside, and a negative pressure is required to fill a new vehicle whose sub-tank is not filled with fuel. There is no known technique for making negative pressure.

(Problems to be Solved by the Invention / Object of the Invention) The present invention aims to extend the fuel supply of a fuel pump for supplying fuel to an engine as much as possible when the fuel tank approaches exhaustion of fuel. In a fuel pump unit in which a pump is provided in a sub-tank of a fuel tank, a sub-tank capable of negative pressure is connected via a canister by connecting a cut-off valve provided in the sub-tank to an evaporation tube communicating with a known cut-off valve of the fuel tank. The negative pressure in the sub-tank as the engine idles, and the negative pressure causes the fuel in the fuel tank to be sucked into the sub-tank to be replenished, thereby causing the fuel pump to supply the fuel to the engine. This is a problem to be solved by the present invention, in which a negative pressure-tight closed sub It is an object of the present invention to install a tank, and to enable a fuel pump installed in the tank to be operated by idling the engine several times even when there is no fuel in the sub tank. It enables refueling of a new vehicle's sub tank.

(Means for Solving the Problems) The present invention meets the above-mentioned object, in which a closed sub-tank that becomes a negative pressure due to internal air suction is provided in the fuel tank, and a replenishing port is provided at the bottom of the fuel tank. The supply tube and the return tube facing each other are connected to the sub-tank, and a fuel pump is installed inside the sub-tank. Inside the sub-tank, the valve is raised to close the valve port when the fuel level rises. A first cut-off valve is provided by being connected to a first suction tube outside the sub-tank, and a second cut-off valve inside the fuel tank is connected to an external second suction tube through which a check valve is inserted. A first tube provided with the first and second suction tubes connected to an evaporation tube connected to an engine, and further including a first check valve for stopping gas from the evaporation tube side; The present invention relates to a fuel pump unit characterized in that the first and second tubes of a canister provided with a second tube having a second check valve for stopping gas from the gas side are communicated with the evaporation tube. .

A preferred embodiment of the present invention will be described below.

(Embodiment) FIGS. 1 to 3 show an embodiment of the present invention, and FIG. 4 shows another embodiment of the first cut-off valve.

In FIGS. 1 to 3, 1 is a fuel tank, 3 is a sealing lid which is provided in the working hole 2 of the fuel tank 1 so as to prevent fuel leakage, and is sealed on the lower surface thereof in cooperation with the sealing lid 3, or A sub-tank 4 is provided which is hermetically sealed and becomes a negative pressure by suction of the inner air. A refueling tube 5 and a return tube 8 are connected to the sub-tank 4, a fuel pump 6 is installed inside, and a fuel supply pipe 7 on the discharge side is projected to the outside from a hermetically closed lid.
The cut-off valve 9 is provided inside and connected to the external first suction tube 10a. The replenishment tube 5 has a replenishment port projecting from the bottom of the sub-tank 4, and a bag-shaped filter 11 attached to the replenishment port is brought into contact with the bottom of the center of the fuel tank 1. When it is not possible to attach the filter 11, the substantially horizontal portion of the replenishment tube 5 projecting from the bottom of the sub tank 4 is extended to the center of the bottom of the fuel tank 1 and the filter 11 is attached. The refueling tube 5 has a fuel injection port at the upper end opened to an upper portion of the sub tank 4, but it may be located at a position lower than that shown in the drawing.

The fuel pump 6 has a bottom portion fixed to a mounting seat 12 provided at the bottom inside the sub tank 4, and a fuel supply pipe 7 for the engine is projected from the sealing lid 3 to the outside. The fuel pump 6 is provided with the suction tube 13 close to the bottom of the sub tank 4.

The sub-tank 4 enables refueling from the refueling tube 5 by setting a negative pressure of about 150 mmAq or less.

The return tube 8 returns about 70-80% of the fuel supplied by the fuel pump 6 to the sub-tank 4 when the engine load is stable, and about 20% when the engine load is high such as high-speed traveling.
Return ~ 30% fuel. Since the return fuel contains some gasification of the fuel, the return tube 8 is opened to the opposite side of the suction tube 13 of the fuel pump 6 and the gasification rises above the liquid level of the sub tank 4. And separate.

The first cutoff valve 9 is a kind of air valve, and the center of the bottom is opened as shown in FIG. This first cut-off valve 9 is provided with a valve seat plate 15 having a valve opening 16 inside a valve cylinder 14, and a valve 18 which is raised by a balance spring 17 as the fuel surface P ₁ of the fuel in the sub-tank 4 rises. Even if the fuel returned by the return tube 8 becomes
When the fuel surface P ₁ is low as shown, the valve port 16 remains open.

Reference numeral 21 denotes a second cutoff valve mounted on the inner surface of the top portion of the fuel tank in a known manner, and like the first cutoff valve 9, a valve 22 that rises as the fuel surface of the fuel tank 1 rises, It has a valve opening 23 closed by a valve 22 and is connected to a second suction tube 10b outside the fuel tank 1, and a check valve C ₁ is inserted in the second suction tube 10b. The second suction tube 10b is connected to the evaporation tube 24 together with the first suction tube 10a. The evaporation tube 24 is connected to the engine by a connection tube 26.

Reference numeral 25 is a canister, which is a first tube 25 having a first check valve C ₂ for stopping gas from the evaporation tube side.
a and a second check valve C for stopping gas from the canister side
The second tube 25b with the ₃ inserted is connected to the evaporation tube 24 as shown in FIG.

FIG. 4 shows another embodiment of the cut-off valve 9, in which a passage 15a having a valve opening 16a is provided inside a valve cylinder 14a, and a resin having a specific gravity of about 1.4 as the fuel surface P ₁ in the sub tank rises. The fuel tank 1 which raises the valve making 18a under the co-operation of the elastic force of the balance spring 17a and closes the valve opening 16a.
If is turned upside down, the valve 18a closes the valve port 16a by its own weight.

(Operation and Effect) The present invention enables negative pressure inside the sub-tank 4,
A first cut-off valve 9 is provided in the sub tank 4,
A configuration in which the first suction tube 10a connected to the valve 9 is connected to the evaporation tube 24 together with the second suction tube 10b of the check valve C ₁ connected to the second cut-off valve 21 of the fuel tank 1, and the canister 25 a first Chiyubu 25a which interposed a first check valve C ₂ to stop gas from Ebapochiyubu side, a second Chiyubu 25b which interposed a second check valve C ₃ to stop gas from Kiyanisuta side Ebapochiyubu 24 The check valve C is configured to communicate with each other.
₁ , the first check valve C ₂ and the second check valve C ₃ have related effects. That is, in the state of FIG. 1 in which all the check valves are closed, the suction of the engine causes the evaporation tube 24 and the first suction tube 10a to have a negative pressure, and the sub-tank 4 also has a negative pressure, so that the fuel surface P ₁ When the float valve 18 of the cutoff valve 9 floats up and closes the valve port 16, the evaporation tube 24 further increases the negative pressure, and the first check valve C ₂ is opened to open the canister. The fuel gas adsorbed on the activated carbon in 25 is sucked into the engine. Further, when the engine is stopped and the pressure of the fuel gas generated by the temperature in the fuel tank 1 becomes equal to or higher than the set value of the check valve C ₁ , the check valve C ₁ is opened, and the fuel tank 1 is opened.
The fuel gas inside has a special effect that it is adsorbed by the activated carbon inside by opening the second check valve C ₃ via the evaporation tube 24 and flowing into the canister 25. As it is a new car, fuel is supplied to the sub tank. Even if it is not, the internal air of the tank 4 is made a negative pressure by idling the engine several times to suck and replenish the fuel at the bottom of the fuel tank 1 from the replenishment pipe 5.
At the same time, fuel supply to the engine is started by the fuel pump 6. This action can correspond to a configuration in which the fuel cannot be replenished into the sub tank 4 unless the sub tank 4 has a negative pressure. Pump 6
In a state in which the fuel pump 6 is enabled, the fuel pump 6 pumps to supply the fuel in the sub-tank 4 to the engine, whereby the engine operates, and a negative pressure is generated by the suction action to generate the negative pressure by the supply pipe 5. The present invention can be used in a new vehicle state in which the sub-tank 4 capable of negative pressure is not filled with fuel or in a vehicle which is already filled with fuel because it can cause automatic refueling. Since the first cut-off valve 9 prevents the fuel surface P ₁ of the sub-tank 4 from reaching a certain height, the sub-tank 4 can be replenished only with the fuel consumed by the engine. It is possible to bring about effects peculiar to the present invention such as a small amount.

[Brief description of drawings]

The attached drawings show an embodiment of the present invention. Fig. 1 is a vertical sectional front view, Fig. 2 is an enlarged vertical sectional front view of the same portion, and Fig. 3 is an enlarged vertical sectional front view showing an example when the fuel in a sub tank 4 is reduced. Is. FIG. 4 is a vertical sectional view showing another embodiment of the cutoff valve. 1 → Fuel tank 3 → Sealing lid 4 → Sub tank 5 → Replenishment tube 6 → Fuel pump 7 → Fuel supply pipe 8 → Return tube 9 → First cut-off valve 10a → First suction tube 10b → Second suction tube 21 → Second cut-off valve 24 → evaporation tube 25 → canister 25a → first tube 25b → second tube C ₁ → check valve C ₂ → first check valve C ₃ → second check valve

Claims (1)

[Claims] 1. A fuel tank is provided with a closed sub-tank which becomes negative pressure due to internal air suction, and a refueling tube having a replenishing port facing the bottom of the fuel tank and a return tube are connected to the sub-tank. A pump is installed inside the sub-tank, and a first cut-off valve is provided inside the sub-tank, which is connected to a first suction tube outside the sub-tank to raise the valve and close the valve opening when the fuel level rises. A second cutoff valve is provided in the fuel tank so as to be connected to an external second suction tube having a check valve inserted therein, and the first and second suction tubes are connected to an evaporation tube connected to an engine. , And a first tube with a first check valve for stopping gas from the evaporation tube side,
A fuel pump unit characterized in that the first and second tubes of a canister provided with a second tube having a second check valve for stopping gas from the canister side communicated with the evaporation tube.