PUMPING DEVICE FOR A WASTE HEAT RECOVERY APPARATUS IN A MOTOR VEHICLE

Abstract

A pumping device may include a pump housing partially delimiting a working chamber, and a piston arranged therein, axially movable between first and second positions in which the working chamber has maximum and minimum volumes, respectively. The pumping device may include first and second fluid lines for introducing and discharging fluid to/from the working chamber, respectively. The first fluid line may be an annular fluid channel, fluidically connected to the working chamber via a breakthrough formed in the pump housing at an end face of the working chamber opposite the piston, running transversely to the axial direction at least in the area of the breakthrough. The second fluid line may open obliquely into the working chamber in an area of the second position, relative to the axial direction in an end face delimiting the working chamber towards the first fluid line. The pumping device may include first and second valves for fluid-tight closures of the first and second fluid lines, respectively, the second valve communicating fluidically with the working chamber directly.

Claims

1. A pumping device for a waste heat recovery apparatus, comprising: a pump housing partially delimiting a working chamber that is fillable with a fluid; a piston arranged in the working chamber and movable along an axial direction between a first position in which the working chamber has a maximum volume and a second position in which the working chamber has a minimum value, volume; a first fluid line for introducing the fluid into the working chamber; a second fluid line for discharging the fluid from the working chamber, the second fluid line opening into the working chamber in an area of the second position of the piston; wherein the first fluid line is fluidically connected to the working chamber via a breakthrough formed in the pump housing at an end face of the working chamber opposite the piston; wherein a first valve for a fluid-tight closure of the first fluid line with respect to the working chamber is provided in at least one of an area of the breakthrough and the working chamber; wherein a second valve for a fluid-tight closure of the second fluid line with respect to the working chamber is provided in an opening area of the second fluid line into the working chamber; wherein the first fluid line runs transversely to the axial direction at least in the area of the breakthrough; wherein the first fluid line is configured as an annular fluid channel; wherein the second fluid line opens obliquely into the working chamber relative to the axial direction in an end face delimiting the working chamber towards the first fluid line; and wherein the second valve communicates fluidically with the working chamber directly.

2. The pumping device according to claim 1, wherein the annular fluid channel extends in a plane perpendicular to the axial direction.

3. The pumping device according to claim 1, wherein the first valve communicates fluidically directly with the first fluid line.

4. The pumping device according to claim 1, wherein the first valve is arranged completely in the working chamber and communicates fluidically via the breakthrough directly with the first fluid line.

5. The pumping device according to claim 1, wherein the first valve at least partially projects into the working chamber.

6. The pumping device according to claim 1, wherein the opening area of the second fluid line is provided in an axial end section of the working chamber facing the first fluid line.

7. The pumping device according to claim 1, wherein the second fluid line opens in a circumferential wall circumferentially delimiting the working chamber.

8. The pumping device according to claim 1, wherein the second valve forms a part of at least one of a circumferential-side delimitation of the working chamber and an end-face-side delimitation of the working chamber.

9. The pumping device according to claim 1, wherein the second valve ends substantially flush with an end face delimiting the working chamber towards the first fluid line.

10. The pumping device according to claim 1, wherein the first valve is a non-return valve adjustable between an open position and a closed position, and is adjusted from the closed position into the open position when a fluid pressure in the first fluid line is greater than in the working chamber by a predetermined threshold value.

11. The pumping device according to claim 1, wherein the second valve is a non-return valve adjustable between an open position and a closed position, and is adjusted from the closed position into the open position when a fluid pressure in the working chamber is greater than in the second fluid line by a predetermined threshold value.

12. The pumping device according to claim 1, wherein the opening area of the second fluid line is arranged in relation to an axial position of the opening area such that the piston does not close the opening area in the axial position.

13. The pumping device according to claim 1, wherein the first valve one of projects into the working chamber or is arranged in the working chamber such that a volume between the piston in its second position and the first valve has a minimum value.

14. The pumping device according to claim 1, wherein a resilient element is provided in the working chamber, and is supported at one end on the first valve and at another end on the piston, and pre-tensions the piston towards the first position.

15. A pump arrangement, comprising three pumping devices each having: a pump housing partially delimiting a working chamber that is fillable with a fluid; a piston arranged in the working chamber and movable along an axial direction between a first position in which the working chamber has a maximum volume and a second position in which the working chamber has a minimum volume; a first fluid line configured as an annular fluid channel for introducing the fluid into the working chamber, the first fluid line being fluidically connected to the working chamber via a breakthrough formed in the pump housing at an end face of the working chamber opposite the piston, and running transversely to the axial direction at least in the area of the breakthrough; a second fluid line for discharging the fluid from the working chamber, the second fluid line opening into the working chamber in an area of the second position of the piston, and opening obliquely into the working chamber relative to the axial direction in an end face delimiting the working chamber towards the first fluid line; a first valve for a fluid-tight closure of the first fluid line with respect to the working chamber in at least one of an area of the breakthrough and the working chamber; and a second valve for a fluid-tight closure of the second fluid line with respect to the working chamber in an opening area of the second fluid line into the working chamber, the second valve communicating fluidically with the working chamber directly; wherein the working chambers of the three pumping devices are arranged with the breakthroughs parallel to one another in relation to the axial direction; wherein the pumping arrangement of the three working chambers with the breakthroughs has a 120 rotational symmetry in a cross-section perpendicular to the axial direction in relation to a predefined symmetry point; and wherein the first fluid lines of the three pumping devices are formed as a common annular fluid channel with the symmetry point as an annular centre point of the annular fluid channel.

16. A waste heat recovery apparatus, comprising: a fluid cycle through which a fluid is flowable; and one of a pumping device and a pump arrangement arranged in the fluid cycle for driving the fluid; wherein the pumping device includes: a pump housing partially delimiting a working chamber that is fillable with a fluid: a piston arranged in the working chamber and movable along an axial direction between a first position in which the working chamber has a maximum volume and a second position in which the working chamber has a minimum volume; a first fluid line configured as an annular fluid channel for introducing the fluid into the working chamber, the first fluid line being fluidically connected to the working chamber via a breakthrough formed in the pump housing at an end face of the working chamber opposite the piston, and running transversely to the axial direction at least in the area of the breakthrough; a second fluid line for discharging the fluid from the working chamber, the second fluid line opening into the working chamber in an area of the second position of the piston, and opening obliquely into the working chamber relative to the axial direction in an end face delimiting the working chamber towards the first fluid line; a first valve for a fluid-tight closure of the first fluid line with respect to the working chamber in at least one of an area of the breakthrough and the working chamber; and a second valve for a fluid-tight closure of the second fluid line with respect to the working chamber in an opening area of the second fluid line into the working chamber, the second valve communicating fluidically with the working chamber directly; and wherein the pumping arrangement includes three pumping devices arranged to have a 120 rotational symmetry in a cross-section perpendicular to the axial direction in relation to a predefined symmetry point, the first fluid lines of the three pumping devices being formed as a common annular fluid channel with the symmetry point as an annular centre point of the annular fluid channel.

17. The pumping device according to claim 2, wherein the first valve communicates fluidically directly with the first fluid line.

18. The pumping device according to claim 2, wherein the first valve is arranged completely in the working chamber and communicates fluidically via the breakthrough directly with the first fluid line.

19. The pumping device according to claim 2, wherein the first valve at least partially projects into the working chamber.

20. The pumping device according to claim 2, wherein the opening area of the second fluid line is provided in an axial end section of the working chamber facing the first fluid line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In the figures, in each case schematically

[0036] FIG. 1 shows an example of a pump arrangement according to the invention in a perspective view,

[0037] FIG. 2 shows a detailed view of FIG. 1 in which the structure of a pumping device 1 of the pump arrangement is shown in detail,

[0038] FIG. 3 shows a detailed view of the pumping device of FIG. 2 in the area of a working chamber 3 of the pumping device 1,

[0039] FIG. 4 shows a schematic view illustrating the tripod-like structure of the three pumping devices of FIG. 1 in schematic form.

DETAILED DESCRIPTION

[0040] FIG. 1 illustrates in a perspective view an example of a pump arrangement 20 according to the invention. FIG. 2 shows a detailed view of FIG. 1 in which the structure of a pumping device 1 of the pump arrangement 20 is shown in detail. FIG. 3 in turn shows a detailed view of FIG. 2 in the area of a working chamber 3 of the pumping device 1.

[0041] The pump arrangement 20 comprises three pumping devices 1 each configured as stroke or axial piston pumps, which are implemented to form the pump arrangement 20 in the form of a tripod arrangement. This means that the respective pistons 2 of the three pumping devices 1 and the working chambers 3 accommodating the respective pistons 2, which are each delimited by a pump housing 4 are arranged parallel to one another in relation to their axial axis. A piston 2 which can be adjusted along an axial direction A is arranged in each of the three working chambers 3. Each of the three pistons 2 is adjustable axially between a first position in which the working chamber 3 has a maximum volume and a second position in which the working chamber 3 has a minimum volume. A common electric motor 22 which is arranged in a motor housing 21 which extends the pump housing 4 contrary to the axial direction A is used to adjust the three pistons 3. The electric motor 22 can be controlled with the aid of an electric/electronic control unit 25 which is fastened to this on a side of the motor housing 22 facing away axially from the pump housing 4.

[0042] The structure of one of the three pumping devices 1 is explained in detail hereinafter with reference to the diagram in FIG. 2:

[0043] The pump housing 4 together with the piston 2 delimits the working chamber 3 which can be filled with a fluidthe working medium of the pumping device 1. For this purpose the pumping device 1 has a first fluid line 5 which is fluidically connected to the working chamber 3 by means of a breakthrough 9. The breakthrough 9 is formed in the pump housing 4 on an end face 7 of the working chamber 3 opposite the piston 2. The first fluid line 5 runs in the area of the breakthrough 9 transversely to the axial direction A. In this case, the first fluid line 5 extends in the area of the breakthrough 9 in said plane perpendicular to the axial direction A.

[0044] In the example of the figures the first fluid line 5 is configured as a closed annular fluid channel 23 which extends completely in a plane perpendicular to the axial direction A.

[0045] Consequently the first fluid line 5 is configured to be curved in the area of the breakthrough 9.

[0046] In the area of the breakthrough 9 a first valve element 10 for closing the first fluid line 5 is provided in the working chamber 3. In one variant the first valve element 10 can be arranged in the area of the breakthrough 9 also on the side of the first fluid line 5. The first valve element 10 in one variant can also project from the first fluid line 5 through the breakthrough 9 into the working chamber 3 and specifically preferably in such a manner that the dead volume of the working chamber 3 is minimal or even has a zero value. Unnecessary dead volumes can also be avoided if the first valve element 10 communicates fluidically directly with the first fluid line 5, i.e. no intermediate space is formed between the first fluid line 5 and the first valve element 10.

[0047] The formation of undesired dead volumes can also be counteracted in the variant shown in the figures in which the first valve element 10 is arranged completely in the working chamber 3 and communicates fluidically via the breakthrough 9 directly, i.e. without forming an intermediate space, with the first fluid line 5.

[0048] In the example of the figures, the first valve element 10 is a non-return valve 11 which is adjustable between an open and a closed position. In the closed position the first valve element 10 closes the first fluid line 5 with respect to the working chamber 3 in a fluid-tight manner. In the open position the first valve element 10 releases the fluid communication between first fluid line 5 and the working chamber 3 so that the fluid can be introduced from the first fluid line 5 into the working chamber 3. The non-return valve 11 is adjusted from its closed position into its open position when the fluid pressure in the first fluid line 5 is greater than in the working chamber 3 and the pressure difference exceeds a predetermined value. This takes place by an axial movement of the piston 2 away from the breakthrough 9.

[0049] According to FIG. 2, the pumping device 1 also comprises a fluid supply line 24 for introducing the fluid into the first fluid line 5. According to FIG. 2, the first fluid line 5 extends the working chamber 3 along the axial direction A. The fluid supply line 24 opens tangentially into the first fluid line 5 configured as annular fluid channel 23. Alternatively or additionally the fluid supply line 24 can also open obliquely into the first fluid line 5. This can in particular mean that in a longitudinal section of the pumping device 1 along the axial direction A the fluid supply line 24 forms an acute angle with the plane perpendicular to the axial direction A in which the annular fluid channel 23 is arranged.

[0050] For discharging the fluid from the working chamber 3, a second fluid line 6 is provided which opens into the working chamber 3 in the area of the second position of the piston 2this position is shown in FIG. 2 and also in the detailed view of FIG. 3. The opening area 12 of the second fluid line 6 is therefore - in the same way as the first fluid line 5 arranged on the front sidearranged in an axial end section 14 of the working chamber 3 facing the first fluid line 5. The second fluid line 6 opens into the working chamber 3 in a transition region between a circumferential wall 15 of the pump housing 4 delimiting the working chamber 3 and an end wall delimiting the pump housing 4 towards the first fluid line 5. The second fluid line 6 opens obliquely into the working chamber 3 relative to the axial direction A. An orifice opening 16 of the second fluid line 6 is arranged in relation to its axial position in such a manner that the piston 2 specifically does not close the orifice opening 16 in its second position.

[0051] Corresponding to the breakthrough 9 of the first fluid line 5, a second valve element 13 for optional fluid-tight closure of the second fluid line 6 with respect to the working chamber is also provided in the orifice area 12 of the second fluid line 6 into the working chamber 3. The second valve element 13, in the same way as the first valve element 10, is implemented as a non-return valve 17. In contrast to the first valve element 10 however it is adjusted from the closed into the open position when the fluid pressure in the working chamber 3 is greater than in the second fluid line and the pressure difference exceeds a predetermined threshold value. This takes place if the piston 2 is moved along the axial direction A towards the breakthrough 9.

[0052] In the example of the figures, the second valve element 13 which is arranged in the transition region between circumferential-side and end-face-side delimitation of the working chamber 3, forms a part of the circumferential-side and end-face-side delimitation of the working chamber 3. Ideally the second valve element 13 ends substantially flush with the end face and/or circumferential side delimiting the working chamber 3 towards the first fluid line 5. An undesired recess promoting the formation of cavitation can in this way be largely or even completely avoided.

[0053] As shown in FIGS. 2 and 3, a resilient element 19 can be provided in the working chamber 3. This is supported according to FIG. 3 at one end on the first valve element 10 and at the other end on the piston 2 and thus pre-tensions the piston 2 towards the first position.

[0054] Finally, the already-mentioned tripod-like arrangement of the pump arrangement 20 is explained with reference to FIG. 4. To this end, FIG. 4 shows the structure of FIG. 2 in a cross-section perpendicular to the axial direction A in a roughly schematic view. The three working chambers 3 of the three pumping device 1indicated by dashed lines in FIG. 4are arranged parallel to one another along the axial direction A. As FIG. 4 clearly confirms, the arrangement of the three working chambers 3 in the cross-section perpendicular to the axial direction A exhibits a 120 rotational symmetry in relation to a predefined symmetry point S. The three first fluid lines 5 here are formed as a common annular fluid channel 23 with the symmetry point S as annular central point M. The fluid channel 23 can be arranged in a plane perpendicular to the axial direction A.

[0055] In this way, the formation of the first fluid line 5 as an annular fluid channel 23 can be used to supply the working chambers 3 of all three pumping devices 1 with the working medium in the manner described above. This ensures that the formation of undesired cavitation both in the fluid channel 23 and in the three working chambers 3 can be largely or even completely prevented.

[0056] The three second fluid lines 6 open according to FIG. 2 into a common fluid discharge line 8.