DE102009026964A1 - fuel pump - Google Patents

Abstract

A fuel pump (1), which serves in particular as a pump arrangement for fuel injection systems of air-compressing self-igniting internal combustion engines, has at least one housing part (3), a first gearwheel (15) and a second gearwheel (16). The gears (15, 16) in the housing part (3) are arranged. Further, the gears (15, 16) mesh with each other to form a gear pump (17). Further, a supply or return (35, 36) for the gear pump (17) is provided, which is provided in the housing part (3).

Description

State of the art

The The invention relates to a fuel pump, in particular a pump arrangement with a gear pump. Specifically, the invention relates to the field the fuel injection systems of air-compressing, self-igniting Internal combustion engines.

From the DE 197 36 160 A1 a pump arrangement for high-pressure fuel supply in fuel injection systems of internal combustion engines is known. The known pump arrangement is used in particular for a common rail injection system. The known pump arrangement has a radial piston pump with a drive shaft mounted in a pump housing, which is formed eccentrically or has cam-like elevations in the circumferential direction. Furthermore, several, with respect to the drive shaft radially arranged in a respective cylinder chamber piston are provided, which are reciprocated when turning the drive shaft in the cylinder chamber and forth. In addition, a low pressure pump upstream of the radial piston pump is provided. In order to achieve a compact design of the pump assembly and to reduce the risk of the occurrence of leakage points, the low-pressure pump is provided on or in the pump housing of the radial piston pump on the side facing away from the drive side and driven by the drive shaft of the radial piston pump. Here, a coupling is interposed between the drive shaft of the radial piston pump and a shaft of the low-pressure pump. The housing of the low-pressure pump is mounted on the pump housing of the radial piston pump via a centering device. Furthermore, a projecting in the direction of the housing of the low-pressure pump Zentrierflansch is provided on the pump housing of the radial piston pump, with which the housing of the low-pressure pump is positioned. To guide fuel to the low-pressure pump, a channel is led to a suction chamber of the low-pressure pump, which communicates with a channel in the pump housing of the radial piston pump. From the channel in the pump housing of the radial piston pump, the fuel is fed to the suction side of the low-pressure pump.

The from the DE 197 36 160 A1 known pump assembly has the disadvantage that the design is relatively complex. Specifically, the low-pressure pump must be reliably connected to the radial piston pump, with a reliable sealing effect in several places is required to ensure reliable operation.

Disclosure of the invention

The inventive fuel pump with the features of claim 1 has the advantage that the structure of the fuel pump is simplified. Specifically, a space of the fuel pump can be optimized become.

By the measures listed in the dependent claims are advantageous developments of specified in claim 1 Fuel pump possible.

Advantageous is it that both an inlet and a return to the housing part are provided that the inlet at least partially formed by a formed in the housing part Supply channel is designed and that the return at least partially by a return channel formed in the housing part is designed. This allows the inlet and the return in the housing part in which the gear pump is provided is to be integrated. This is a compact embodiment of Fuel pump possible. Specifically, an additional Component that serves to accommodate a low-pressure circuit, saved become.

Advantageous It is also here that the inlet channel with the return channel over an inserted in the housing part overflow valve and / or via an inserted into the housing part Bypass valve are interconnected. Thus, too the overflow valve and the bypass valve in the Housing part, in which the gear pump is arranged integrates become.

In Advantageously, the housing part with an external Cover closed. The housing part can both take the gear pump as well as the complete low-pressure circuit. Through the outer lid, in particular the gear pump be closed in the field of gears.

Advantageous it is that the housing part receives a low-pressure unit, that a further housing part is provided, the one High-pressure unit receives, and that the gear pump by a Driven in the further housing part drive shaft driven is. The housing part of the low pressure unit can thereby directly connected to the housing part of the high pressure unit be. A lid or the like, between the housing part the low pressure unit and the housing part of the high pressure unit can be provided, this can be omitted. This is a compact Design of the fuel pump possible. Specially can an axial space of the fuel pump can be shortened.

It is also advantageous here that the housing part of the low-pressure unit has a recess on a side facing the housing part of the high-pressure unit, which at least partially a coupling part receives a provided between the drive shaft and the gear pump clutch. As a result, expansion of the fuel pump in the axial direction can be further shortened. It is also advantageous that the coupling part has an outer side and that the coupling part is mounted on its outer side in the recess of the housing part of the low pressure unit. This allows the design of the fuel pump, in particular the housing parts of the fuel pump, simplified and thus optimized.

Possible However, it is also the case that both a High-pressure unit and the gear pump receives. This can the gear pump directly into the housing part of the high pressure unit to get integrated. Specifically, in this case, the low-pressure circuit be integrated into the housing part of the high-pressure unit, resulting in a compact design of the fuel pump.

Advantageous it is the case that the housing part as a one-piece housing part is designed. A clutch and / or other components or Components can be saved as a result. Thereby is a cost effective solution possible. Furthermore, an overall length of the fuel pump can be optimized become.

Advantageous it is that the housing part formed of an alloy is based on aluminum and silicon. Especially it is advantageous that the housing part of a hypereutectic Alloy is formed with aluminum and silicon. Such an aluminum-silicon alloy allows the storage of elements of the fuel pump, wherein a nickel plating of the bearing surfaces or the like omitted can. Specifically, the gears of the gear pump mounted directly on the material of the alloy of the housing part be, so that a nickel plating of the bearing surfaces of the gear pump is not necessary. This simplifies the design the fuel pump, at the same time a wear and trouble-free design possible is.

preferred Embodiments of the invention are in the following Description with reference to the accompanying drawings, in which corresponding elements with matching reference numerals are provided, explained in more detail. It shows:

1 a fuel pump in an excerpt, axial sectional view according to a first embodiment of the invention;

2 a section through the in 1 illustrated fuel pump along the designated II section line in a schematic representation;

3 the in 1 labeled III section of a fuel pump according to a second embodiment of the invention and

4 the in 1 labeled III section of a fuel pump according to a third embodiment of the invention.

1 shows a fuel pump in a fragmentary, axial sectional view according to a first embodiment. The fuel pump 1 can be configured in particular as a pump arrangement for fuel injection systems of air-compressing, self-igniting internal combustion engines. A preferred use of the fuel pump 1 consists of a fuel injection system with a common rail, which stores diesel fuel under high pressure. The fuel pump according to the invention 1 However, it is also suitable for other applications.

The fuel pump 1 has housing parts 2 . 3 on, which are interconnected. Here is a page 4 of the housing part 3 one page 5 of the housing part 2 facing. The housing part 3 lies with his side 4 on the side 5 of the housing part 2 on, with a sealing ring for sealing between the housing parts 2 . 3 is provided. The housing part 2 has a passage opening 7 on, in which a drive shaft 8th is arranged at least in sections. Here is in the 1 a warehouse 9 represented by means of which the drive shaft 8th in the case 2 is stored. The warehouse 9 is in the through hole 7 arranged. The passage opening 7 is at the side 5 of the housing part 2 by means of the sealing ring 6 sealed against the environment.

In this embodiment, the fuel pump 1 a high pressure unit 10 and a low pressure unit 11 on. This takes the housing part 2 the high pressure unit 10 on. Furthermore, the housing part takes 3 the low pressure unit 11 on. The high pressure unit 10 For example, may have a radial or in-line piston pump, which from the drive shaft 8th is drivable. The low pressure unit 11 includes, for example, a low-pressure pump described in detail below, as well as low-pressure side bores or channels for inlet and / or outlet and optionally one or more valves.

In the housing part 3 the low pressure unit 11 are gears 15 . 16 arranged to form a gear pump 17 comb each other. The gear pump 17 is thus in the low printing unit 11 integrated. The housing part 3 points one side 4 far away side 18 on. The page 18 is an outside side 18 of the housing part 3 the fuel pump 1 , On the side 18 of the housing part 3 is a lid 19 attached, the housing part 3 closes. Through the lid 19 Here are the gears 15 . 16 the gear pump 17 covered. The lid 19 serves as an external lid 19 , Here is between the lid 19 and the housing part 3 a sealing ring 20 provided to the gear pump 17 seal to the outside.

In operation of the fuel pump 1 rotates the drive shaft 8th around an axis 21 , The housing part 3 has a bearing bore 22 on. In the bearing bore 22 is a hub 23 stored. The hub 23 extends through the bearing bore 22 of the housing part 3 , The gear 16 is with the hub 23 connected. Furthermore, a bearing pin 24 provided on which the gear 15 is stored. In this embodiment, the bearing pin 24 on the housing part 3 designed. An axis 25 the hub 23 is at least approximately on the axis 21 , Thus, the axes are right 21 . 25 at least approximately agree.

The hub 23 has one of the drive shaft 8th facing head section 26 on. Between the hub 23 and the drive shaft 8th is a coupling part 27 arranged with the drive shaft 8th rotatably connected. Further, the hub 23 with a coupling part 28 connected to the hub 23 encloses. The coupling part 28 is next to the page 4 of the housing part 3 arranged. The coupling parts 27 . 28 form a clutch 29 between the drive shaft 8th and the hub 23 , The head section 26 the hub 23 is in a recess 30 of the coupling part 27 arranged. The coupling 29 allows a certain balance between the drive shaft 8th and the hub 23 , For example, an axis offset between the axis 21 the drive shaft 8th and the axis 25 the hub 23 be compensated. In addition, compensation can be made if the axles 21 . 25 not exactly aligned coaxially with each other.

When rotating the drive shaft 8th takes the drive shaft 8th over the clutch 29 the hub 25 With. Thus, the gear becomes 16 and thus also the gear pump 17 in operation of the fuel pump 1 from the drive shaft 8th driven.

The fuel pump 1 of the first embodiment is hereinafter also with reference to the 2 described in further detail.

2 shows a schematic section through the in 1 illustrated fuel pump 1 along the section line marked II. The fuel pump 1 has an inlet 35 and a return 36 on. The feed 35 and the return 36 are there for the gear pump 17 provided and on the housing part 3 intended. About the inlet 35 can take fuel from a tank from the gear pump 17 be sucked. About the return 36 can that of the gear pump 17 subsidized fuel from the housing part 3 be guided. The one from the return 36 Guided fuel can then go to the high pressure unit 10 be led to produce the desired high pressure. The gear pump 17 serves as a low pressure pump 17 ,

The feed 35 has an inlet channel 37 on, in the housing part 3 is trained. Furthermore, the return line 36 a return channel 38 on, which is also in the housing part 3 is trained. The inlet channel 35 flows at a confluence point 39 in the gear pump 17 , The estuary 39 thus represents the suction side of the gear pump 17 dar. The from the gear pump 17 subsidized fuel reaches an outlet point 40 of the return channel 38 so that the confluence 40 the delivery side of the gear pump 17 represents. The positions of the gears 15 . 16 the gear pump 17 are in the 2 by broken lines 15 ' . 16 ' illustrated.

The housing part 3 also has stepped holes 41 . 42 on. The stepped holes 41 . 42 each connect the inlet channel 37 with the return channel 38 , In the stepped bore 41 is an overflow valve 43 arranged. Furthermore, in the stepped bore 42 a bypass valve 44 arranged. Thus, the inlet channel 37 and the return channel 38 on the one hand via the overflow valve 43 and the other via the bypass valve 44 connected with each other. The overflow valve 43 and the bypass valve 44 can thus together with the gear pump 17 in the housing part 3 the low pressure unit 11 to get integrated. This results in a compact construction of the fuel pump 1 , In particular, an expansion, that is a space, the fuel pump 1 in the axial direction, that is along the axis 21 or the axis 25 , Can be reduced because additional housing parts can be omitted. For example, no additional housing part for receiving the gear pump 17 required.

3 shows the in 1 with III designated section of a fuel pump 1 according to a second embodiment. In this embodiment, the housing part 3 the low pressure unit 11 at the housing part 2 the high pressure unit 10 facing side 4 a recess 50 on. The recess 50 is designed cylindrical. Furthermore, the cylindrical recess 50 on the axis 25 aligned. In the recess 50 is the coupling part in this embodiment 28 the clutch 29 at least in the Essentially arranged. The recess 50 thus takes the coupling part 28 on. The coupling part 28 has an outside 51 on. On its outside 51 is the coupling part 28 in the recess 50 of the housing part 3 stored.

The recess 50 has a depth 52 on, in which the recess 50 of the page 4 of the housing part 3 in the direction of the axis 25 in the housing part 3 extends. To this depth 52 can the hub 23 closer to the drive shaft 8th be arranged compared to the first embodiment. Thus, the housing part 2 the high pressure unit 10 about the depth 52 be shortened in the axial direction. This allows the axial length of the fuel pump 1 be further optimized.

In the case of the 1 and 2 described first embodiment and in the reference to the 3 described second embodiment, the housing part 3 to the housing part 2 attached and with a bunch 53 in the passage opening 7 of the housing part 2 used. As a result, a reliable centering of the bearing bore 22 in relation to the axis 21 the drive shaft 8th allows. However, it is also possible that the housing part 2 and the housing part 3 are designed in one piece. In this case, a housing part 2 . 3 provided so that the gear pump 17 in the housing part 2 . 3 the high pressure unit 10 is integrated, as it is based on the 4 is described.

4 shows the in 1 with III designated section of a fuel pump 1 according to a third embodiment. In this embodiment, instead of a two-part design with the housing part 2 and the housing part 3 a one-piece housing part 2 . 3 intended. In this case, therefore, is a housing part 2 . 3 provided, as a one-piece housing part 2 . 3 is designed. The gear pump 17 is thus in the housing part, so to speak 2 . 3 the high pressure unit 10 integrated.

Advantageous in this one-piece design of the housing part 2 . 3 is that a coupling and / or other components or components can be saved by this. This makes a cost effective solution possible. Furthermore, a length of the fuel pump 1 be optimized.

The housing part 3 and optionally also the housing part 2 are preferably formed of an alloy based on aluminum and silicon. Specifically, the housing part 3 be formed of a hypereutectic alloy with aluminum and silicon. As a result, a wear-resistant mounting of the gears 15 . 16 in the housing part 3 possible. Specifically, the gear can 15 directly on the material of the bearing pin 24 of the housing part 3 be stored. Furthermore, the hub 23 acting as a bearing for the gear 16 serves, directly on the material of the housing part 3 , namely in the area of the bearing bore 22 be stored. A nickel coating or the like can thereby be dispensed with.

Thus, in particular by the reduced part circumference of the fuel pump 1 a cost saving and easier installation possible. Furthermore, a scope of inspection can be reduced and an amount of processing can be reduced. In addition, the coupling of the gear pump 17 to the drive shaft 8th be robust, thereby extending the life of the fuel pump 1 increased. Furthermore, interfaces are saved, which are required for example in a separate external gear pump. As a result, a risk of leakage can be reduced.

The Invention is not limited to the described embodiments limited.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19736160 A1 [0002, 0003]

Claims (12)

Fuel pump ( 1 ), in particular pump arrangement for fuel injection systems of air-compressing, self-igniting internal combustion engines, with at least one housing part ( 3 ), a first gear ( 15 ) and a second gear ( 16 ), wherein the first gear ( 15 ) and the second gear ( 16 ) in the housing part ( 3 ) are arranged and mesh with each other to form a gear pump and wherein a supply or return ( 35 . 36 ) for the gear pump ( 17 ) is provided, which on the housing part ( 3 ) is provided. Fuel pump according to claim 1, characterized in that an inlet ( 35 ) and a return ( 36 ) on the housing part ( 3 ) are provided that the inlet ( 35 ) at least in sections by a in the housing part ( 3 ) formed inlet channel ( 37 ) and that the return ( 36 ) at least in sections by a in the housing part ( 2 ) formed return channel ( 38 ) is configured. Fuel pump according to claim 2, characterized in that the inlet channel ( 37 ) with the return channel ( 38 ) via a in the housing part ( 3 ) inserted overflow valve ( 43 ) and / or via a in the housing part ( 3 ) inserted bypass valve ( 44 ) are interconnected. Fuel pump according to one of claims 1 to 3, characterized in that the housing part ( 3 ) with an outer lid ( 19 ) is closed. Fuel pump according to one of claims 1 to 4, characterized in that the housing part ( 3 ) a low pressure unit ( 11 ) receives that another housing part ( 2 ), which is a high-pressure unit ( 10 ) and that the gear pump ( 17 ) by a in the further housing part ( 2 ) mounted drive shaft ( 8th ) is drivable. Fuel pump according to claim 5, characterized in that the housing part ( 3 ) of the low pressure unit ( 11 ) on one of the housing part ( 2 ) of the high pressure unit ( 10 ) facing side ( 4 ) a recess ( 50 ), which at least partially a coupling part ( 28 ) one between the drive shaft ( 8th ) and the gear pump ( 17 ) provided coupling ( 29 ). Fuel pump according to claim 6, characterized in that the coupling part ( 28 ) an outside ( 51 ) and that the coupling part ( 28 ) on its outside ( 51 ) in the recess ( 50 ) of the housing part ( 3 ) of the low pressure unit ( 11 ) is stored. Fuel pump according to one of claims 1 to 4, characterized in that the housing part ( 2 . 3 ) a high pressure unit ( 10 ) and the gear pump ( 17 ). Fuel pump according to claim 8, characterized in that the housing part ( 2 . 3 ) as a one-piece housing part ( 2 . 3 ) is configured. Fuel pump according to one of claims 1 to 9, characterized in that the housing part ( 2 . 3 ) is formed of an alloy based on aluminum and silicon. Fuel pump according to claim 10, characterized in that the housing part ( 2 . 3 ) is formed of a hypereutectic alloy with aluminum and silicon. Fuel pump according to claim 10 or 11, characterized in that the gears ( 15 . 16 ) of the gear pump ( 17 ) on the material of the housing part ( 3 ) are stored.