JP2001132571A - Fuel tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supplement fuel to a reservoir cup inside a fuel tank with certainty by utilizing pressure caused inside the fuel tank. SOLUTION: A chamber 11 is arranged on an upper side of a fuel tank 1. The fuel tank 1 is connected to the chamber 11 by means of a first fuel passage 10, while the chamber 11 is connected to a reservoir cup 2 by means of a second fuel passage 12. A check valve 14 which is normally closed is arranged on an end of the second fuel passage 12, while a liquid level adjusting valve 15 is arranged on a top of the chamber 11. The liquid level adjusting valve 15 interrupts communication between the chamber 11 and a relief passage 16 during rising of the liquid level inside the chamber 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank used for a vehicle or the like, and more particularly, to a fuel tank provided with a reservoir cup for a fuel suction port opened in the fuel tank.

[0002]

2. Description of the Related Art In a fuel tank used for a vehicle or the like, a fuel intake port opened in the fuel tank is prevented from being exposed from a fuel level when the vehicle body is tilted or turning. Although the reservoir cup is provided, since the amount of liquid stored by the reservoir cup is limited, there is a possibility that the engine cannot be operated continuously for a long time while the vehicle body is inclined.

For this reason, as exemplified in Japanese Patent Application Laid-Open No. Hei 5-231256, when excess oil of fuel supplied from a fuel pump is returned to a fuel tank by a return pipe, a fuel suction utilizing the return flow is performed. By the action of the pump, the fuel in the sub tank is guided into the baffle cylinder surrounding the fuel inlet to the fuel pump.However, when the engine is idling, the return flow rate of the surplus oil is greatly reduced, There is a problem that a sufficient suction force is not always obtained in the fuel suction pump.To solve this problem, it is necessary to increase the capacity of the fuel pump to improve the performance of the fuel suction pump. In this case, problems such as an increase in the operating noise of the fuel pump occur.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to replenish fuel to a reservoir cup in a fuel tank by utilizing pressure generated in the fuel tank.

[0005]

For this purpose, a fuel tank according to the present invention is provided with a reservoir cup installed at the bottom and containing a fuel inlet, one end opening into the fuel liquid at the bottom and the other end at the reservoir. A fuel passage extending into the cup, a chamber provided at a position higher than the liquid surface of the fuel liquid in the middle of the fuel passage, and having a communication passage to outside air, A shutoff valve for closing the communication passage; and a check valve provided on the other end side of the fuel passage to allow a fuel liquid to flow from the chamber to the reservoir cup.

Therefore, if the temperature of the entire fuel tank rises during a high temperature in summer or the like, the pressure in the fuel tank also rises due to the vapor pressure of the fuel liquid in the fuel tank. Since the pressure inside the chamber is suppressed from increasing by the communication path to the outside air, the fuel liquid in the fuel tank is pushed up from one end of the fuel passage into the chamber by the pressure difference between the fuel tank and the chamber. When the fuel level in the chamber rises and the shut-off valve closes the communication path, the check valve provided at the other end of the fuel path and the fuel liquid in the chamber opens by its own weight, and the fuel valve in the chamber opens by its own weight. It will flow into the cup.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention shown in the drawings will be described below. 1 and 2, a reservoir cup 2 is provided at the bottom of a fuel tank 1 used for a vehicle or the like, and a filter 3 and a fuel pump 4 are disposed in the reservoir cup 2. A fuel pump 4 facing the filter 3 Is located at the bottom in the reservoir cup 2, and fuel is supplied from the fuel pump 4 to an engine (not shown) via a fuel supply passage 5, while excess fuel in the engine is supplied to the fuel by a passage 6. It is designed to be returned into the tank 1.

A first fuel passage 10 having one end opened near the bottom surface of the fuel tank 1 is connected to a chamber 11 disposed above the fuel tank 1, and a second fuel passage 12 connected to the chamber 11 is connected to another chamber. A check extending at one end into the reservoir cup 2 and at the connection of the first fuel passage 10 to the chamber 11 allows fuel fluid to flow from the first fuel passage 10 into the chamber 11 as described below. A check valve 14 is provided at the other end of the second fuel passage 12. The check valve 14 allows the fuel liquid to flow from the second fuel passage 12 into the reservoir cup 2 as described later. Is provided.

Further, a liquid level adjusting valve 15 is provided near the top of the chamber 11, and a normally closed relief valve 17 is provided in a relief path 16 extending from the liquid level adjusting valve 15. A common shut-off valve 18 for preventing fuel from flowing out is mounted on the top of the shut-off valve 1.
A pressure holding valve 2 which is normally closed is provided in an air passage 19 extending from
0 is provided, and the valve opening pressure of the relief valve 17 is set lower than that of the pressure holding valve 20.

As shown in FIG. 2, the liquid level adjusting valve 15 opens the valve port 23 of the valve plate 22 at a position below the float 21 and closes the valve port 23 when the float 21 rises. The float 21 can be further raised while the bellows 24 holding the valve plate 22 is elastically reduced, and thereafter, when the float 21 is lowered, the float 21 keeps the valve port 23 closed. The bellows 24 is elastically extended, and the float 21 opens the valve port 23 when the bellows 24 is almost fully extended.

In the above apparatus, when the temperature of the entire fuel tank 1 rises at a high temperature in summer or the like, and the pressure in the fuel tank 1 rises due to the vapor pressure of the fuel liquid 25 in the fuel tank 1, the chamber responds accordingly. Since the pressure in the chamber 11 also increases, the relief valve 17 is easily opened, and the chamber 11 communicates with the outside air through the relief path 16 to reduce the pressure in the chamber 11. As a result, the fuel liquid 25 in the fuel tank 1 passes through the first fuel passage 10, opens the check valve 13, and is pushed up into the chamber 11.

Accordingly, the amount of the fuel liquid in the chamber 11 increases, and the float 21 of the liquid level control valve 15 rises due to the raised fuel liquid level, closes the valve port 23, and the liquid level control valve 1
When the pressure difference between the fuel tank 1 and the chamber 11 disappears as a result of the float 21 further rising due to the shrinkage of the bellows 24 in 5, the check valve 14 provided at the other end of the second fuel passage 12 becomes The fuel liquid in the chamber 11 is opened by its own weight, and the fuel liquid in the chamber 11 flows into the reservoir cup 2 through the second fuel passage 12 as appropriate,
The fuel liquid is supplied into the reservoir cup 2.

That is, since the internal pressure of the fuel tank 1 rises, the fuel liquid is supplied into the reservoir cup 2.
Even if the fuel liquid 25 stored in the fuel tank 1 decreases, the fuel liquid can be sufficiently and automatically stored in the reservoir cup 2,
The inlet to the fuel pump 4 located in the reservoir cup 2 can be always closed by the fuel liquid.
Even when the vehicle is stopped on a slope, it is possible to always start the engine or operate for a relatively long time, and it is also necessary to particularly increase the capacity of the fuel pump as in the conventional device. There are features that disappear.

A sensor 26 for detecting the temperature and internal pressure of the fuel tank 1 is attached to the fuel tank 1, and the output signal of the sensor 26 allows the check valve 13, the check valve 14, the liquid level adjusting valve 15, the relief valve It is possible to perform the same operation as described above by electrically controlling the opening and closing of 17 and the like as appropriate. Further, even if the chamber 11 is arranged at the upper part in the fuel tank 1, It goes without saying that the same operation and effect as the embodiment can be obtained.

[0015]

According to the fuel tank of the present invention,
In response to the pressure increase in the fuel tank, the fuel liquid pushed up from the fuel tank into the chamber by the pressure difference between the fuel tank and the chamber opens the check valve provided at the other end of the fuel passage. Since the fuel liquid flows into the reservoir cup and the fuel liquid is supplied to the reservoir cup, even if the fuel liquid stored in the fuel tank is reduced, the fuel liquid is sufficiently and automatically stored in the reservoir cup. Even if the fuel tank is inclined
There is an advantage that the inlet to the fuel pump located in the reservoir cup can be always closed by the fuel liquid.

[Brief description of the drawings]

FIG. 1 is a schematic layout diagram in an embodiment of the present invention.

FIG. 2 is a partially enlarged longitudinal sectional view of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Reservoir cup 4 Fuel pump 10 First fuel passage 11 Chamber 12 Second fuel passage 13 Check valve 14 Check valve 15 Liquid level adjusting valve 16 Relief path 25 Fuel liquid

Claims (1)

[Claims] A reservoir cup provided at a bottom for receiving a fuel inlet; a fuel passage having one end open to the fuel liquid at the bottom and the other end extending into the reservoir cup; A chamber provided at a position higher than the fuel liquid level and provided with a communication passage to the outside air, a shutoff valve for closing the communication passage as the fuel liquid level rises in the chamber, and the other end of the fuel passage A fuel valve having a check valve provided on a side thereof to allow a flow of fuel liquid from the chamber to the reservoir cup.