Pump Device For Feeding Fuel In A Fuel Tank

Abstract

A pump device for feeding fuel in a fuel tank of a motor vehicle, having a suction jet pump and having a control valve for regulating the feed rate of the suction jet pump, A valve body can be moved counter to the flow direction of a fuel jet of the suction jet pump to throttle the feed rate. In this way, forces for opening the control valve are kept low. A float controls the valve body via a shaft which is guided through a mixing tube of the suction jet pump.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a pump device for feeding fuel in a fuel tank of a motor vehicle, having a suction jet pump that includes a nozzle arranged upstream of a mixing tube and an intake region of the suction jet pump, the intake region arranged between the nozzle and mixing tube, a control valve for controlling the feed rate of the suction jet pump, and a control valve body controlling the flow of a propellant jet through the nozzle.

2. Related Art

A pump device of this type is known, from DE 10 2005 043 888 A1. In said pump device, the suction jet pump is arranged in a liquid trap of a venting device and is supplied with fuel as propellant by a fuel pump via a propellant line. A level limit switch that activates a control valve arranged within the propellant line is arranged within the liquid trap. When the liquid trap is filled with fuel, the control valve opens the propellant line, and therefore the suction jet pump draws off fuel that is accumulated within the liquid trap. When the liquid trap is empty, the control valve blocks the supply of fuel to the suction jet pump and prevents fuel from being unnecessarily conveyed within the fuel tank. Foaming in the fuel tank is therefore prevented. In addition, unregulated fuel pumps reduce the volume flow of propellant jet available for the internal combustion engine of the motor vehicle. In regulated fuel pumps, this saves on electric energy.

A disadvantage of the known pump device is that the valve body is constantly exposed to the pressure of the propellant line.

In addition, during closing of the control valve, the valve body is moved in the direction of flow directly into the nozzle of the suction jet pump. When the control valve is closed, a possible excess pressure within the propellant line cannot escape. Opening of the control valve counter to the pressure within the propellant line is therefore possible only with a high expenditure of energy.

Furthermore, a pump device has been known in practice, in which the mixing tube of the suction jet pump is closed when feeding of fuel is not desired. However, when the mixing tube is closed, this results in fuel overflowing out of the propellant line into the suction connection. Said pump device is therefore incapable of preventing unnecessary feeding of fuel.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, is a pump device of the type mentioned at the beginning avoids unnecessary feeding of fuel within the fuel tank and that the expenditure of energy for opening the control valve is kept as low as possible.

According to one embodiment of the invention, a valve body can be moved toward that end of the nozzle that faces the mixing tube in order to throttle the feed rate of the suction jet pump.

This configuration results in the closing direction of the valve body being counter to the direction of flow within the propellant line. The pressure within the propellant line therefore assists the opening movement of the control valve, and an expenditure of energy for opening the control valve is kept particularly low. Since the control valve directly controls the flow at the nozzle of the suction jet pump, an unnecessary feeding of fuel can be avoided in a simple manner. A further advantage of this configuration is that disturbance of the flow within the propellant line when the control valve is open is largely avoided.

The valve body could be pivoted, for example transversely, onto that end of the nozzle which faces the mixing tube in order to throttle the feed rate of the suction jet pump. According to an advantageous development of the invention, a particularly simple control of the effective cross section of the nozzle and therefore of the feed rate of the suction jet pump can be achieved in a simple manner if the direction of movement of the valve body is guided counter to the direction of flow of the propellant jet in order to throttle the flow of the propellant jet. The control valve also has the function of a pressure control valve because of the direction of movement of the valve body in order to throttle the feed rate and permits an excess pressure in the propellant line to escape.

The effective cross section of the nozzle could be controlled from the side facing away from the mixing tube and therefore through the nozzle. However, according to another advantageous development of the invention, throttling of the flow of the fuel when the control valve is open can be kept particularly low if the valve body is arranged on a shaft which is guided through the mixing tube.

The throttling of the flow of the fuel when the control valve is open is further reduced if the valve body is conical, tapering toward that end of the nozzle that faces the mixing tube. This configuration is advantageous in particular for the valve body arranged on the shaft guided through the mixing tube, since, in the open position of the control valve, the valve body can be pushed into the mixing tube and is matched by its conical configuration to the generally likewise conical contour of the inlet region of the mixing tube. The valve body here can taper toward the nozzle. Therefore, the control valve contributes in the open position thereof to the functioning of the suction jet pump.

According to another advantageous development of the invention, the control valve in the closed state ensures a high degree of tightness of the nozzle if that end of the nozzle that faces the mixing tube has a valve seat configured in a manner corresponding to the valve body. This keeps leakage of fuel in the propellant line particularly low.

According to another advantageous development of the invention, the constructional outlay on activating the control valve can be kept particularly low if the shaft is connected to a float for activating the control valve. This configuration also makes it possible to keep the level in a surge pot of a fuel tank constant in a simple manner if the float is arranged in the surge pot and the suction jet pump is designed for feeding fuel into the surge pot.

According to another advantageous development of the invention, an effect on the position of the float by the feeding carried out by the suction jet pump can be kept particularly small if the float is fastened directly on the shaft, and if a wall is arranged between a float for controlling the control valve and the free end of the mixing tube. Furthermore, the pump device according to the invention has a particularly small number of movable components as a result.

The pump device according to the invention proves to be particularly simple structurally if the mixing tube is guided into a liquid trap, and if the wall separating the float from the mixing tube is part of the liquid trap.

The installation of the pump device according to one embodiment of the invention in the fuel tank proves to be particularly simple if the suction jet pump is arranged within a surge pot designed to collect fuel. By this configuration, the components of the pump device according to one embodiment of the invention and the surge pot can be preassembled in a simple manner outside the fuel tank to form a constructional unit and can be inserted together into the fuel tank. In addition, the function of the components of the pump device according to the invention and of the surge pot can be checked outside the fuel tank in a simple manner. The liquid trap is preferably also arranged within the surge pot.

The manufacturing costs of the feed unit according to the invention are further reduced if the liquid trap is designed as a pocket in a side wall or in a cover of the surge pot.

BRIEF DESCRIPTION OF DRAWINGS

The invention permits numerous embodiments. To further clarify the basic principle of the invention, one of the embodiments is illustrated in the drawings and is described below. In the drawings:

FIG. 1 is a schematic representation of a surge pot arranged in a fuel tank, with a pump device according to the invention arranged in said surge pot; and

FIG. 2 is a sectional illustration through the pump device along the line II-II in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a surge pot 2 arranged within a fuel tank 1 of a motor vehicle and with a first pump device 3 and a second pump device 4 for feeding fuel into the surge pot 2. The two pump devices 3, 4 each have a respective suction jet pump 5, 6. The first pump device 3 is connected via a suction line 7 to a suction connection 8, which is remote from the surge pot 2.

During operation of the pump devices 3, 4 and when the surge pot 2 is empty, the first pump device 3 draws fuel via the suction line 7 from the remote suction connection 8 while the second pump device 4 draws fuel directly from the surroundings of the surge pot 2. The pump devices 3, 4 feed fuel together into the surge pot 2. The first pump device 3 is arranged in the surge pot 2 in a liquid trap 9 designed as a pocket in the surge pot 2. The second pump device 4 is located in the base region of the surge pot 2. An electrically driven fuel pump 10, which is arranged within the surge pot 2 and is illustrated schematically, draws fuel from the surge pot 2 and feeds said fuel to an internal combustion engine (not illustrated) of the motor vehicle and as propellant to the suction jet pumps 5, 6. The pump devices 3, 4 therefore ensure that there is sufficient fuel in the surge pot 2 at all times, therefore the fuel pump can draw fuel out of the surge pot. Furthermore, FIG. 1 shows that a level sensor 11 for detecting the fuel level in the fuel tank 1 is arranged on the surge pot 2.

FIG. 2 is a sectional illustration through that sub region of the surge pot 2 that has the first pump device 3, along the line II-II from FIG. 1. It can be seen here that the liquid trap 9 is arranged on a cover 12 of the surge pot 2. The cover 12 is connected to a side wall 13 of the surge pot 2, and the suction jet pump 5 of the first pump device 3 is connected to a nozzle 15 arranged upstream of a mixing tube 14. An intake region 16, which is connected via a suction connecting piece 17 to the suction line 7 illustrated in FIG. 1 is arranged between the nozzle 15 and the mixing tube 14. The free end of the mixing tube 14 opens into the liquid trap 9. The suction jet pump 5 has a propellant connection 18 for connection to the delivery side of the fuel pump 10 illustrated in FIG. 1.

Furthermore, the first pump device 3 has a control valve 19 that throttles the feed rate of the suction jet pump 5 when the surge pot 2 is full. The control valve 19 therefore avoids unnecessary feeding of fuel if the surge pot 2 is already filled with fuel. For this purpose, the control valve 19 has a float 20 arranged within the surge pot 2, for detecting a designated maximum level in the surge pot 2. The float 20 is connected to a valve body 22 of the control valve 19 via a shaft 21. That side of the nozzle 15 that faces the mixing tube 14 has a valve seat 23 that interacts with the valve body 22. As the fuel level in the surge pot 2 rises, the float 20 is raised, as a result of which the valve body 22 is pressed against the valve seat 23. As the level in the surge pot 2 rises, the feed rate of the suction jet pump 5 of the first pump stage 3 is therefore throttled. The valve body 22 is of conical configuration. In the open position of the control valve 19, the conically configured valve body 22 is located in a conically configured section 24 of the mixing tube 14. The range of movement of the float 20 is restricted by a stop 25 (illustrated schematically). In an alternative embodiment (not illustrated), the range of movement of the valve body 22 can be restricted by a stop arranged in the nozzle 15. A wall 26 is arranged between the open end of the mixing tube 14 and the float 20. The wall 26 is part of a base of the liquid trap 9 and prevents a jet produced by the suction jet pump 5 from affecting the movement of the float 20.

Of course, given a corresponding deflection of the movement of the float, the control valve may also be provided in the second pump device illustrated in FIG. 1 in order also to regulate the feed rate here as a function of the level in the surge pot.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

1.-10. (canceled)

11. A pump device for feeding fuel in a fuel tank of a motor vehicle, comprising: a suction jet pump, comprising: a mixing tubea nozzle arranged upstream of the mixing tube;an intake region of the suction jet pump arranged between the nozzle and the mixing tube;a control valve for controlling a feed rate of the suction jet pump comprising a control valve body configured to control a flow of a propellant jet through the nozzle, the valve body configured to move in a direction toward an end of the nozzle that faces the mixing tube to throttle the feed rate of the suction jet pump.

12. The pump device as claimed in claim 11, wherein the direction of movement of the valve body to throttle the flow of the propellant jet is counter to a direction of flow of the propellant jet.

13. The pump device as claimed in claim 12, further comprising a shaft guided through the mixing tube on which the valve body is arranged.

14. The pump device as claimed in claim 13, wherein the valve body is of conical configuration that tapers toward an end of the nozzle that faces the mixing tube.

15. The pump device as claimed in claim 14, wherein the end of the nozzle that faces the mixing tube comprises a valve seat configured to mate with the valve body.

16. The pump device as claimed in claim 15, wherein the shaft is coupled to a float to activate the control valve.

17. The pump device as claimed in claim 16, further comprising: a wall arranged between the float for controlling the control valve and the free end of the mixing tube,wherein the float is fastened directly to the shaft.

18. The pump device as claimed in claim 17, wherein the mixing tube is guided into a liquid trap, the wall separating the float from the mixing tube is part of the liquid trap.

19. The pump device as claimed in claim 18, wherein the suction jet pump is arranged within a surge pot designed to collect fuel.

20. The pump device as claimed in claim 19, wherein the liquid trap is configured as one of a pocket in a side wall of the surge pot and in a cover of the surge pot.

21. The pump device as claimed in claim 11, further comprising a shaft guided through the mixing tube on which the valve body is arranged.

22. The pump device as claimed in claim 11, wherein the valve body is of conical configuration, tapering toward the end of the nozzle that faces the mixing tube.

23. The pump device as claimed in claim 11, wherein the end of the nozzle that faces the mixing tube comprises a valve seat configured to mate with the valve body.

24. The pump device as claimed in claim 13, wherein the shaft is coupled to a float for activating the control valve.

25. The pump device as claimed in claim 11, wherein the suction jet pump is arranged within a surge pot configured to collect fuel.

30. The pump device as claimed in claim 18, wherein the liquid trap is configured as one of a pocket in a side wall of the surge pot and in a cover of the surge pot.