DE102011011167A1 - Fuel system for motor vehicle e.g. car, has control unit that is provided for controlling fuel delivery through ejector based on level of fuel in surge chamber - Google Patents

Abstract

The invention relates to a fuel system, in particular a motor vehicle, comprising a fuel tank (1), a fuel feed pump (4) arranged in a delivery or swirl pot (6), a suction jet pump (17) for delivering fuel into the delivery or swirl pot (6 ) and control means (25) for controlling the fuel delivery by the suction jet pump (17). In order on the one hand to reduce the energy consumption by delivering fuel into the delivery or surge pot (6), but on the other hand to ensure that the internal combustion engine is always supplied with fuel even in dynamic driving conditions, it is proposed according to the invention that the control means in the feed or surge pot ( 6) arranged control valve (25), which controls the fuel delivery depending on the fuel level (26) in the delivery or surge pot (6).

Description

The invention relates to a fuel system according to the preamble of claim 1, in particular a fuel system of a motor vehicle.

The fuel system of a motor vehicle generally comprises a fuel tank and a fuel delivery pump, with which fuel is conveyed from the fuel tank to an internal combustion engine of the motor vehicle. In order to ensure that the internal combustion engine is always supplied with sufficient fuel even when the fuel tank is largely empty even in dynamic driving conditions, the fuel delivery pump is usually arranged in a so-called conveyor or swirl pot, which is separated from the remainder of the fuel tank by a circumferential boundary wall. To fill the production or swirl pot, during operation of the fuel delivery pump, part of the fuel pumped by the fuel delivery pump is circulated through at least one suction steel pump, which is located outside the delivery or swirl pot in the fuel tank and after the Venturi principle further fuel into the conveyor - or swirl pot sucks when it is flowed through by the circulated fuel.

From the DE 10 2007 032 410 A1 a fuel system of the type mentioned is already known, in which the fuel delivery is controlled by the suction jet pump in dependence on the delivery volume and / or the delivery pressure of the fuel delivery pump. Next discloses the DE 197 19 607 A1 a fuel system in which the fuel delivery is controlled by the suction jet pump in dependence on the fuel consumption of the fuel delivery pump.

In addition, at least fuel systems of newer passenger cars are equipped with a tank venting device, which allows refueling of the gas mixture displaced from the fuel from the interior of the fuel tank when refueling the motor vehicle. In order to prevent hydrocarbons from escaping from the fuel tank into the atmosphere or environment when the gas mixture escapes, the tank venting device generally comprises an activated carbon filter which absorbs the volatile hydrocarbons contained in the gas mixture. However, since the gas mixture displaced in the venting of fuel tanks often contains not only volatile but also liquid hydrocarbons in the form of small droplets, a liquid separator is usually provided between the fuel tank and the activated carbon filter, which is referred to as a liquid trap in the present patent application. In the liquid trap, the liquid hydrocarbons are separated from the gas mixture to prevent unwanted supply of liquid fuel into the activated carbon filter. The emptying of the liquid trap is expediently also by means of a suction jet pump.

In order to reduce the energy consumption by such a suction jet pump in the liquid trap, it is out of the DE 10 2005 043 888 A1 already known to provide a switchable valve in the liquid trap, which opens or closes depending on the fuel level in the liquid trap. The valve opens above a predetermined level in the liquid trap to provide fuel to the ejector and, in the event of an empty liquid trap, shuts off the ejector.

Based on this, the invention has the object, on the one hand to reduce energy consumption by the promotion of fuel in the production or swirl pot, on the other hand, however, always ensure a supply of the internal combustion engine with fuel in dynamic driving conditions.

This object is achieved in that the control means comprise a control valve arranged in the delivery or swirl pot, which controls the fuel delivery in dependence on the fuel level in the delivery or swirl pot.

The invention is based on the idea, on the one hand by commissioning the ejector pump fuel in the production or swirl pot to promote when the fuel level in the production or swirl pot drops below a level at which sufficient supply to the engine is compromised, at least in certain dynamic driving conditions, and on the other hand to interrupt the operation of the suction jet pump when the fuel level in the delivery or swirl pot again exceeds a level at which an adequate supply of the internal combustion engine is ensured.

As a result of the measures according to the invention, the energy requirement of the ejector pump required for pumping fuel into the delivery or swirl pot can be reduced since the fuel is only pumped into the delivery or swirl pot if additional fuel is needed there to supply the internal combustion engine.

In other words, it is avoided that fuel is pumped into a full production or swirl pot and immediately overflows again from the production or swirl pot. The measure according to the invention also allows the turbulence of fuel in the production or swirl pot or in the fuel tank and thus also the generation of fuel vapors to be minimized, which in turn the Loading the activated carbon filter can be reduced with volatile hydrocarbons.

A preferred embodiment of the invention provides that the control valve opens automatically and allows the promotion of the fuel by the ejector when the fuel level in the production or swirl pot reaches or falls below a predetermined lower level, and that the control valve closes automatically and the promotion of fuel stops when the fuel in the production or swirl pot reaches or exceeds a predetermined upper level. The upper and lower levels can also coincide.

In order to minimize the susceptibility of the fuel system to failure, a purely mechanical control valve is preferably used, the valve body of which is movable vertically between a lower open position and an upper closed position. The control valve may conveniently be a solenoid valve whose valve body is at least partially made of a magnetic or ferromagnetic material, so that the valve body can be raised or lowered in response to the fuel level by means of a permanent magnet integrated in a float and acting on the valve body by magnetic forces. Where the control valve is disposed along a vertical portion of a line through which fuel flows, an annular float or permanent magnet integrated in the float is preferably used which surrounds a cylindrical valve housing of the control valve and the valve body vertically movable valve body as it rises Presses fuel level against a stationary valve seat and lifts off the valve seat with decreasing fuel level when the fuel level in the delivery or swirl pot reaches the predetermined upper and lower levels. As a result, on the one hand, the space required for the control valve space can be kept as small as possible and on the other hand, the actuator formed by the float and the permanent magnet for the valve body so that it is in the immediate vicinity of the valve body, where the strength of the permanent magnet on the valve body acting magnetic forces is greatest.

Advantageously, a vertical boundary wall of a stationary valve housing is arranged in an annular gap between the actuator and the valve body whose cross-sectional shape corresponds to the cross-sectional shape of an inner circumferential surface of the actuator or permanent magnet and an outer peripheral surface of the valve body. Thereby, the radial distance between the actuator or the permanent magnet and an outer peripheral surface of the valve body and thus also the decrease of the force acting from the actuator or the permanent magnet on the valve body magnetic forces are reduced as much as possible.

In order to facilitate the pressing of the valve body against the flow of the fuel against the valve seat when closing the control valve, the valve advantageously comprises a force acting on the valve body valve spring which acts counter to the flow direction of the fuel through the valve to the valve body.

In principle, the actuating member, which moves the valve body of the solenoid valve depending on the fuel level in the delivery or swirl pot up into the closed position and down into the open position of the valve could also be actuated by a float which is coupled via a lever mechanism to the actuator , As a result, the path of the actuating member between the open and the closed position could be shortened and the necessary to move the valve body buoyancy force can be reduced.

By serving to promote the fuel in the production or swirl pot suction jet pump fuel is circulated with a valve open by a fuel pump. The ejector pump includes a venturi whose annular space is connected by a suction line to the fuel tank so that fuel is drawn from the fuel tank into the production or surge pot when fuel is pumped or circulated through the ejector by the fuel delivery pump.

In the following the invention will be explained in more detail with reference to some schematically illustrated in the drawings embodiments. Show it

1 a schematic view of a portion of a fuel system of a motor vehicle with two Saugstrahlpumpen in the fuel tank;

2 an enlarged schematic view of one of the ejector pumps, which serves to empty a liquid trap;

3 an enlarged schematic view of a first embodiment of a control valve for controlling the other Saugstrahlpumpe;

4 an enlarged schematic view of a second embodiment of a control valve for controlling the other Saugstrahlpumpe;

5 an enlarged schematic view of a third embodiment of a control valve for controlling the other Saugstrahlpumpe;

6 an enlarged schematic view of a fourth embodiment of a control valve for controlling the other Saugstrahlpumpe;

7 an enlarged schematic view of a fifth embodiment of a control valve for controlling the other suction jet pump.

The in 1 illustrated pressure-tight fuel tank 1 an internal combustion engine of a motor vehicle has for refueling through a tank lid 2 lockable filler neck 3 on. The removal of the fuel from the fuel tank 1 takes place by means of a fuel delivery pump 4 by a leading to the engine fuel delivery line 5 , The fuel pump 4 is in an upwardly open cylindrical conveyor or swirl pot 6 Arranged upwards over a floor 7 of the fuel tank 1 survives.

The fuel tank 1 is also equipped with a tank venting device 8th equipped, the refueling of a fuel mixture displaced from the fuel inside the fuel tank when refueling the motor vehicle 1 allowed. The tank ventilation device 8th includes a tank vent line 9 coming from one in the head or gas room 10 of the fuel tank 1 arranged liquid trap 11 from the fuel tank 1 out to one from the engine control unit 12 the internal combustion engine controlled Tankabsperrventil 13 and from there to a communicating with the environment activated carbon filter 14 leads.

The activated carbon filter 14 prevents venting of the fuel tank 1 Volatile hydrocarbons (HC) get into the environment, and for this purpose contains a filling of activated carbon, which absorbs volatile hydrocarbons (HC). When the activated carbon filter 14 is loaded with volatile hydrocarbons, it is regenerated by ambient air through the activated carbon filter 14 is sucked into an intake tract (not shown) of the internal combustion engine to the filter 14 to rinse and to burn the volatile hydrocarbons in the combustion chambers of the internal combustion engine.

The liquid trap 11 forms a liquid separator, with the Tankabsperrventil open 13 prevents liquid from the effluent gas mixture to the activated carbon filter 14 is carried. Since the structure and function of such liquid traps is known, they should not be described in detail here. The lower part of the liquid trap 11 forms a fuel tank 15 in which the separated liquid fuel collects.

The fuel tank 1 also contains two suction jet pumps 17 . 18 of which the suction jet pump 17 to serve the conveyor or swirl pot 6 during operation of the fuel delivery pump 4 Always keep filled and thereby provide adequate supply of the internal combustion engine with fuel, while the suction jet pump 18 for emptying the liquid trap 11 serves.

Each of the two suction jet pumps 17 and 18 is in a branch line 19 . 20 arranged by the delivery line 5 branches off and back into the production or swirl pot 6 leads. If the fuel pump 4 during operation of the internal combustion engine fuel through the delivery line 5 A part of the fuel is pumped through the branch pipe 19 and the suction jet pump 17 circulated, and another part through the branch line 20 and the suction jet pump 18 unless the fuel flow through the branch line 19 or 20 is interrupted.

As in 2 the example of the suction jet pump 18 illustrated, includes each suction jet pump 17 . 18 a Venturi nozzle 21 through which the through the branch line 19 . 20 circulated fuel flows, as well as a suction line 22 into a the Venturi nozzle 21 surrounding annulus 23 empties. When the fuel from the branch line 19 . 20 through the Venturi nozzle 21 flows, arises in the annulus 23 a negative pressure, which is an intake of fuel through the suction line 22 causes. The suction line 22 contains a check valve 24 that provides a return flow of fuel from the suction jet pump 18 in the fuel tank 15 prevented.

As in 1 shown, the suction line opens 22 the suction jet pump 17 near the ground 7 of the fuel tank 1 outside the production or swirl pot 6 while the suction line 22 the suction jet pump 18 in the fuel tank 15 the liquid trap 11 empties.

While the suction jet pump 18 always put into operation when the fuel level 16 in the fuel tank 15 the liquid trap 11 exceeds a predetermined level, the suction jet pump 17 always put into operation when, for example, in dynamic driving conditions, the fuel level in the production or swirl pot 6 falls below a predetermined level and thus there is a risk that the internal combustion engine of the fuel pump 4 is not supplied with a sufficient amount of fuel.

For controlling the suction jet pump 17 contains the branch line 19 behind the suction jet pump 17 a within the conveyor or swirl pot 6 arranged control valve 25 , which closes automatically when the fuel level 26 in the conveyor or swirl pot 6 exceeds a predetermined level, and that automatically opens when the fuel level 26 in the conveyor or swirl pot 6 falls below a predetermined level.

At the control valve 25 it is a float valve, the one in the delivery or swirl pot 6 arranged floats 27 includes an increase or decrease in the fuel level in the production or swirl pot 6 moved up and down and the control valve 25 actuated.

In the in the 3 and 4 illustrated valve is the float 27 annular and surrounds a cylindrical peripheral wall 28 a valve housing 29 of the valve 25 on the outside, so that the float 27 through the valve body 29 guided up and down. The swimmer 27 contains an annular permanent magnet 30 , on the inner circumference of the float 27 arranged and the peripheral wall 28 of the valve housing 29 is adjacent.

Inside the valve housing 29 there is a valve body 31 which is vertically movable. The cylindrical valve body 31 lies in an upper closed position of the valve 25 (in 3 shown in broken lines) against a valve seat 32 and closes the valve 25 or from above into the valve housing 29 opening branch 19 while in a lower open position (in 3 shown in solid lines) from the valve seat 32 is lifted off, leaving fuel through the branch line 19 and the valve 25 into the production or swirl pot 6 can flow. On the valve body 31 acts from below a valve spring 33 one that is dimensioned so that when closing the valve 25 the fluid pressure in the branch line 19 compensated. The valve body 31 consists of a ferromagnetic material, on which from the permanent magnet 30 of the swimmer 27 a magnetic force is exerted when the float 27 on the valve body 31 moved up or down. The magnetic force is directed upward when the float 27 with the permanent magnet 30 with increasing fuel level 26 in the conveyor or swirl pot 6 on the valve body 31 moved upwards while being directed downwards when the float is up 27 with the permanent magnet 30 with decreasing fuel level 26 in the conveyor or swirl pot 6 on the valve body 31 moved downwards. In the former case, the valve body becomes 31 by the magnetic force of the permanent magnet 30 against the valve seat 32 Pressed when the float 27 in the upper closed position of the valve 25 while in the latter case the valve body 31 by the magnetic force of the permanent magnet 30 against the force of the valve spring 33 from the valve seat 32 is lifted when the swimmer 27 in the lower open position of the valve 25 located. In this position, the control valve 25 and thus also the suction jet pump 17 from that of the fuel delivery pump 4 through the branch line 19 circulated fuel flows through, thereby providing additional fuel through the suction line 22 from the fuel tank 1 in the suction jet pump 17 sucked and from there together with the circulated fuel through the branch line 19 into the production or swirl pot 6 is encouraged.

While at the in 3 illustrated control valve 25 the fuel on the outer circumference of the valve body 31 flowed past, when this from the valve seat 32 is lifted off, as in 3 shown, the valve body 34 of in 4 illustrated valve 25 a plurality of passage openings 35 on, reducing the distance between the outer circumference of the valve body 31 and the peripheral wall 28 of the valve housing 29 as well as the permanent magnet 30 reduced and thus the transmission of magnetic forces can be improved.

This in 5 only partially shown control valve 25 is different from the control valves 25 in 3 and 4 in that the permanent magnet 30 not in the swimmer 27 is integrated, but that this side next to the valve 25 in the conveyor or swirl pot 6 arranged and by a lever mechanism 36 with the permanent magnet 30 connected is. The lever mechanism 36 has a longer, with the float 27 connected lever arm 37 and a shorter, with the permanent magnet 30 connected lever arm 38 on, so that the movement path of the permanent magnet 30 reduced and larger forces on the valve body 31 can be transmitted.

While in the 3 to 5 illustrated control valves 25 for installation in vertical sections of the branch line 19 in the conveyor or swirl pot 6 are suitable in 6 and 7 illustrated control valves 25 For installation in horizontal through the conveyor or swirl pot 6 extending sections of the branch line 19 ,

At the in 6 illustrated control valve 25 is the swimmer 27 at its top with a vertical slider 39 provided in a slide housing 40 transverse to the longitudinal axis of the branch line 19 is displaceable. The upper part of the slider 39 limits a flow opening 41 while the bottom to the float 27 adjacent part of the slider 39 closed is. When the swimmer 27 due to an increase in the fuel level 26 in the conveyor or swirl pot 6 from the in 6 Position shown moved so far that no longer with the flow opening 41 provided upper part but the closed lower part of the slider 39 between two to the slide housing 40 adjoining Line sections of the branch line 20 is located, the fuel flow through the branch line 20 interrupted. When the fuel level in the delivery or swirl pot 6 sinks, moves the float 27 with the slider 39 down, resulting from the suction jet pump 17 Fuel from the fuel tank through the suction line 22 sucked in and through the branch line 19 into the production or swirl pot 6 is encouraged.

At the control valve 25 in 7 is the slide shown only schematically 39 with the swimmer 27 via a two-armed lever 42 connected between the slider 39 and the swimmer 27 in a pivot bearing 43 is pivotally mounted. As with the previously described valves 25 will promote fuel through the branch line 19 interrupted when the fuel level 26 in the conveyor or swirl pot 6 above a predetermined upper level, and released again when the fuel level 26 in the conveyor or swirl pot 6 falls below a predetermined lower level.

LIST OF REFERENCE NUMBERS

1

Fuel tank

2

filler cap

3

filler pipe

4

Fuel pump

5

Fuel line

6

Conveying or swirl pot

7

ground

8th

Tank venting device

9

Tank vent line

10

Head or gas room

11

liquid trap

12

Engine control unit

13

Tank ventilation valve

14

Activated carbon filter

15

Fuel sump

16

Fuel level

17

eductor

18

eductor

19

branch line

20

branch line

21

venturi

22

suction

23

annulus

24

check valve

25

control valve

26

Fuel level

27

swimmer

28

peripheral wall

29

valve housing

30

permanent magnet

31

valve body

32

valve seat

33

valve spring

34

valve body

35

Passage openings

36

lever mechanism

37

lever arm

38

lever arm

39

pusher

40

slide housing

41

Port

42

lever

43

pivot bearing

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007032410 A1 [0003]
• DE 19719607 A1 [0003]
• DE 102005043888 A1 [0005]

Claims (8)

Fuel system, in particular of a motor vehicle, with a fuel tank, arranged in a conveyor or swirl pot fuel pump, a suction jet pump for conveying fuel into the conveyor or swirl pot and control means for controlling the fuel delivery by the suction jet pump, characterized in that the control means in the Conveying or swirl pot ( 6 ) arranged control valve ( 25 ), which determines the fuel production in relation to the fuel level ( 26 ) in the conveyor or swirl pot ( 6 ) controls. Fuel system according to claim 1, characterized in that the control valve ( 25 ) automatically opens when the fuel level ( 26 ) in the conveyor or swirl pot ( 6 ) reaches or falls below a predetermined lower level, and that the control valve ( 25 ) closes automatically when the fuel level ( 26 ) in the conveyor or swirl pot ( 6 ) reaches or exceeds a predetermined upper level. Fuel system according to claim 1 or 2, characterized in that the control valve ( 25 ) a vertically movable valve body ( 31 ) and a float coupled to the valve body ( 27 ). Fuel system according to claim 3, characterized in that the float ( 27 ) a permanent magnet ( 31 ), which by magnetic forces on the valve body ( 31 ) acts. Fuel system according to claim 4, characterized in that the float ( 27 ) and / or the permanent magnet ( 31 ) is annular and a valve housing ( 29 ) of the control valve ( 25 ) surrounds. Fuel system according to claim 3 or 4, characterized in that the permanent magnet ( 31 ) the valve body ( 31 ) and against a stationary valve seat ( 32 ) presses when the fuel level ( 26 ) in the conveyor or swirl pot ( 6 ) reaches or exceeds the predetermined upper level. Fuel system according to one of claims 3 to 6, characterized by a counter to the flow direction of the fuel by the control valve ( 25 ) on the valve body ( 31 ) acting valve spring ( 33 ). Fuel system according to claim 3, characterized in that the float ( 27 ) directly or via a lever ( 42 ) on the valve body ( 39 ) acts.

Images