DE10328213A1 - Electric pump device for fluid, especially high-pressure fuel pump for motor vehicle, fuel flow path runs in-part through electric drive or past it, for cooling by fluid supplied - Google Patents

Abstract

An electric pump device (24), especially a high-pressure fuel pump for a combustion engine (10). The flow path (71) of the supplied fluid (fuel) runs upstream from an inlet (70) of the feed device (34), at least in-part through the electric drive device (36) or past it, so that it is cooled by the fluid (fuel) being supplied.

Description

The The invention relates to an electrical pump device for a fluid, in particular high-pressure fuel pump for an internal combustion engine, with an electric drive device and a coupled thereto Conveyor for the to be promoted Fluid.

An electric pumping device of the type mentioned is from the DE 197 09 737 A1 known. In this a fuel delivery system for an internal combustion engine, in particular in a motor vehicle, described, in which two hydraulically connected in parallel electric fuel pumps are present. Also known from the market are fuel systems in which in addition to a directly from the engine mechanically driven high-pressure fuel pump, an electrically driven additional fuel pump is available. In addition, fuel systems are known in internal combustion engines with direct fuel injection, in which an electric prefeed pump and a directly from the internal combustion engine mechanically driven high-pressure fuel pump are present. Furthermore, one knows electric motors, which are cooled by a separate fan.

task The present invention is an electric pumping device of the aforementioned type so that they also as a high-pressure fuel pump can be used, while small builds and a long life having.

These Task is in an electric pumping device of the beginning solved by the type mentioned, that the flow path of the to be promoted Fluids upstream from an inlet of the conveyor at least partially by the electric drive device through or past this is guided so that this of the to be promoted Fluid cooled becomes.

Advantages of invention

The Pumping device according to the invention has the advantage that with it also very high flow rates at the same time small size can be realized can. It is therefore particularly well suited for use as a high-pressure fuel pump in Fuel system of an internal combustion engine. The basis for this is thereby created that the electric drive device through the promoting fluid chilled becomes.

Of the flow of the to be promoted Fluids is chosen that "fresh" and therefore comparatively cool Fluid first through or through the electric drive device passed by becomes. This allows a significant amount of electrical in the Drive device resulting heat loss heat dissipated can. On a separate fan can be dispensed with such a drive device.

at predetermined boundary conditions of the electric pumping device, for example predetermined maximum capacity or maximum delivery pressure, so can the size of the electric Drive device can be reduced because the maximum allowable current density elevated can be. Also the number and size of the electric Drive device existing power components (these are For example, in a drive required) can be reduced.

Furthermore may be due to the comparatively low operating temperatures An inexpensive and easy connection technique can be used. Certain components can be used at all only in the pumping device according to the invention be used because their maximum operating temperature limited is (usually at about 125 up to 175 ° C). Furthermore, the liquid cooling of the electric drive means the operating noise of the electric pump device reduced.

advantageous Further developments of the pumping device according to the invention are in Subclaims specified.

In a first development is proposed that the electric Drive means comprises a stator and a rotor, wherein the stator and / or the rotor during operation of the pumping device at least partially from the fluid to be pumped are surrounded. In this case, the electric drive device So executed as a so-called "wet runner". Especially Cheap It is when the rotor and stator are completely surrounded by the fluid. To this Way is also a permanent lubrication of the bearings of the stator and thus allows a reduction of the bearing friction, and the cooling of the electrical Drive device is particularly good.

It is also proposed that the flow path of the fluid to be delivered passes through a gap between the rotor and the stator. Such a gap is present in all conventional electric drive devices anyway. Due to the relative movement between the rotor and the stator, turbulence of the fluid in this gap occurs, which further improves the heat transfer from the drive device into the fluid. Over there In any case, this is the area in which the thermal energy is generated most in the electric drive device. In this way, therefore, the cooling of the electric drive device is particularly effective.

A further embodiment of the electric pump device according to the invention is characterized by the fact that it has at least one retaining element for at least an electronic component in or on which a channel is present, the part of the upstream of the inlet of the conveyor lying flow path of the to be promoted Fluids is. Such a holding element can, for example, as a plate or lids on which electronic components, For example, a capacitor, resistors, a circuit board, and so on further, are appropriate.

Just These components are particularly heat sensitive and therefore need from excessive temperatures protected become. In the pump device proposed here are the Holding element and thus also the components attached to it cooled by "fresh" fluid, which by a channel flows, which is present in or on the retaining element. This can be the channel straight or, for example, also meandering.

With similar Objective is also suggested that a space in which at least an electronic component is present, part of the upstream of Inlet of the conveyor lying flow path of the to be promoted Fluids is. In this case, so the electronic component even of the to be promoted Fluid flows around and cooled directly. This is especially effective.

The cooling the electronic component can be improved by they by means of a heat-conducting Mold compound is connected to the holding element.

In the same direction is aimed at those training in which the electronic component in a recess of the retaining element is arranged. In this way, the heat transfer surface is increased, which the heat dissipation facilitated by the electronic component.

Further It is suggested that the material from which the retaining element is made of aluminum. Aluminum is a good conductor of heat, something likewise to a particularly good heat dissipation of the thermal Energy from the electrical component ultimately in the promotional F1uid enabled.

A Particularly preferred embodiment of the pump device according to the invention provides that the electric drive device and the conveyor form a structural unit. Such a unit can, for example through a common housing for the realized electrical drive device and the conveyor become. It is compact and yet, thanks to the cooling provided by the electric drive unit, be powerful.

drawing

following become particularly preferred embodiments the present invention with reference to the accompanying Drawing closer explained.

In show the drawing:

1 a schematic representation of an internal combustion engine with a fuel system, which comprises an electric pumping device with an electric drive device and a conveyor;

2 a schematic partial section through the electric pumping device of 1 ;

3 a representation similar 2 an alternative embodiment;

4 a perspective partially sectioned view of the pumping device of 3 ; and

5 a perspective view of a portion of the pumping device of 4 ,

description the embodiments

In 1 an internal combustion engine carries the reference numeral 10 , It includes a fuel system 12 ,

This in turn consists inter alia of a fuel tank 14 from which a prefeed pump 16 that a pump 17 includes which of an electric motor 18 is driven, the fuel into a low-pressure fuel line 20 promotes. This is with an inlet 22 a high pressure fuel pump 24 connected, which is indicated schematically by dotted lines. The high pressure fuel pump 24 compresses the fuel to a very high pressure and delivers it via an outlet 26 to a fuel rail 28 ( "Rail"). In turn, these are several fuel injectors 30 connected, the the fuel directly in each assigned combustion chambers 32 the internal combustion engine 10 inject.

The high pressure fuel pump 24 includes a hydraulic conveyor 34 generated by an electric drive device 36 is driven. Especially the latter is in 2 presented in more detail.

Thereafter, the high pressure fuel pump includes 24 for the hydraulic conveyor 34 and the electric drive device 26 a common housing 38 , A housing section 40 belongs to the electric drive device 36 , He has a total cylindrical shape. A disc-shaped retaining element 42 is inside the housing section 40 attached. In him and a front wall 44 of the housing section 40 is a drive shaft 46 stored, on the turn a rotor 48 is attached. This is in the known way of a stator 50 surround. Between rotor 48 and stator 50 is a gap 52 available.

About the drive shaft 46 becomes the hydraulic conveyor 34 driven. Even if this is in 2 is not explicitly shown, it is in the hydraulic conveyor 34 to a three-cylinder radial piston pump.

Between the disk-shaped holding element 42 and one of the front wall 44 opposite end wall 54 of the housing section 40 is a cover plate 56 (For example, a printed circuit board), and between this and the holding element 42 are different electronic components 58 and 60 arranged. These may be, for example, capacitors, resistors, etc. They are by means of a thermal adhesive 62 with the holding element 42 thermally connected.

How out 2 shows, the retaining element 42 in his in 2 lower area a passage 64 on, which one between the holding element 42 and the cover plate 56 formed space 66 with a between the holding element 42 and the front wall 44 formed space 68 combines. Furthermore, in the front wall 44 , which the housing section 40 the electric drive device 36 to the hydraulic conveyor 34 limited to one passage 70 present, in the in 2 upper area of the front wall 44 ,

The high pressure fuel pump 24 works as follows: By applying an electrical energy, the rotor 50 and the rigidly connected drive shaft 46 set in rotation. This starts the hydraulic conveyor 34 To promote fuel. This "fresh", so not yet substantially compressed and therefore comparatively cool fuel flows to the high-pressure fuel pump 24 over the inlet 22 to and first enters the between the holding element 42 and the cover plate 56 lying room 66 , There it flows on the electronic components 58 and 60 over and cool this and the retaining element 42 and the shaft bearing located therein (without reference numerals).

Then he gets over the passage 64 in the holding element 42 in that room 68 in which the rotor 48 and the stator 50 available. He now flows through the annular gap 52 between rotor 48 and stator 50 through and becomes the hydraulic conveyor 34 finally on the passage 70 in the front side 44 of the housing section 40 fed. The corresponding flow path is in 2 dashed lines and bears the reference numeral 71 ,

In this way, the electric drive device 36 from the "fresh" and cool fuel that you get from the pre-feed pump 16 is provided, cooled. Only after the fuel, the electric drive device 36 it flows through the hydraulic conveyor 34 compressed and over the outlet 26 into the fuel rail 28 pressed.

An alternative embodiment of a high pressure fuel pump 24 is in 3 shown. In this case, such elements and areas, which have equivalent functions to elements and areas of in 2 have shown high-pressure fuel pump, the same reference numerals. Normally they will not be explained again in detail.

The differences relate firstly to the flow path 71 fuel from the inlet 22 into the room 68 : From the inlet 22 the flow path leads 71 not in the room 66 but in a channel 72 , in the holding element 42 is trained and im in 3 lower area of the room 68 facing end face (without reference numeral) of the retaining element 42 empties. At the in 3 shown high-pressure fuel pump 24 become the electronic components 58 and 60 So not directly washed by the fuel, but the room 66 is from the fuel-filled room 68 fluidly isolated or sealed against this.

Instead, the retaining element 42 through the channel 72 cooled by fresh inflowing fuel. To heat transfer from the electrical components 58 and 60 to the holding element 42 to optimize, are the components 58 and 60 in respective wells 74 respectively 76 arranged in which the room 66 facing end face of the retaining element 42 are introduced. In this way, the surface, which for the Heat transfer is available, increased.

A comparatively detailed account of in 3 only schematically shown fuel high-pressure pump 24 is in the 4 and 5 shown. Again, such elements and areas that have already been explained in connection with previous figures will not be described again in detail. They also carry the same reference numerals.

Particularly well recognizable in 4 the hydraulic conveyor 34 , You can see that the drive shaft 46 in the area of the hydraulic conveyor 34 an eccentric section 78 has, as is usual with radial piston pumps. On both sides of the eccentric section 78 is the drive shaft 46 in the area of the hydraulic conveyor 34 through bearings 80 stored. In the in 4 shown section plane is a cylinder 82 the, as has already been stated above, a three-cylinder radial piston pump comprehensive, hydraulic conveyor 34 visible, noticeable. It is in a housing 84 a piston 86 moved back and forth. He limits a workspace 88 in which the fuel is at an upward movement of the piston 86 is compressed.

In the 4 and 5 are also the electronic components 58 and 60 a bit more detailed. One recognizes in 4 a transistor 58 and a capacitor 60 , Furthermore, one recognizes that the cover plate 56 is designed as a circuit board.

Claims (9)

Electric pump device ( 24 ) for a fluid, in particular high-pressure fuel pump for an internal combustion engine ( 10 ), with an electric drive device ( 36 ) and a conveyor coupled thereto ( 34 ) for the fluid to be delivered, characterized in that the flow path ( 71 ) of the fluid to be delivered upstream of an inlet ( 70 ) of the conveyor ( 34 ) at least partially by the electric drive device ( 36 ) or past it is guided so that it is cooled by the fluid to be delivered. Electric pump device ( 24 ) according to claim 1, characterized in that the electric drive device ( 36 ) a stator ( 50 ) and a rotor ( 48 ), wherein the stator ( 50 ) and / or the rotor ( 48 ) during operation of the pumping device ( 24 ) are surrounded at least partially by the fluid to be delivered. Electric pump device ( 24 ) according to one of claims 1 or 2, characterized in that the flow path ( 71 ) of the fluid to be delivered through a gap ( 52 ) between rotor ( 48 ) and stator ( 50 ) passes through. Electric pump device ( 24 ) according to one of the preceding claims, characterized in that it comprises at least one holding element ( 42 ) for at least one electronic component ( 58 . 60 ) in or on which a channel ( 72 ), the part of the upstream of the inlet ( 70 ) of the conveyor ( 34 ) lying flow path ( 71 ) of the fluid to be delivered. Electric pump device ( 24 ) according to one of the preceding claims, characterized in that a space ( 66 ), in which at least one electronic component ( 58 . 60 ), part of the upstream of the inlet ( 70 ) of the conveyor ( 34 ) flow path ( 71 ) of the fluid to be delivered. Electric pump device ( 24 ) according to one of claims 4 or 5, characterized in that the electronic component ( 58 . 60 ) by means of a thermally conductive molding compound ( 62 ) with the retaining element ( 42 ) connected is. Electric pump device ( 24 ) according to one of claims 4 to 6, characterized in that the electronic component ( 58 . 60 ) in a depression ( 74 . 76 ) of the retaining element ( 42 ) is arranged. Electric pump device ( 24 ) according to one of claims 4 to 7, characterized in that the material from which the retaining element ( 42 ), aluminum comprises. Electric pump device ( 24 ) according to one of the preceding claims, characterized in that the electric drive device ( 36 ) and the conveyor ( 34 ) an assembly ( 38 ) form.