DE102009000965A1 - High pressure fuel pump with integrated high pressure accumulator - Google Patents

Abstract

The invention relates to a high-pressure fuel pump for an internal combustion engine, comprising a drive shaft (5) rotatably mounted in a housing (1; 1 '; 1') which, when rotating via at least one drive element (4), has at least two pump elements (3a, 3b). set in motion, wherein by the movement of the at least two pump elements (3a, 3b) in respectively associated pressure chambers (6a, 6b) fuel sucked, compressible to high pressure and in a high-pressure line (9; 9 ', 9' ') is conveyed, which at the same time forming a high-pressure accumulator and communicating with ports (10a, 10b; 10a-10c; 10a-10d) for discharging the fuel, further wherein the at least two pumping elements (3a, 3b) are placed in a plane around the drive shaft (5) and in each case one, on the housing (1; 1 ', 1' ') mounted pump cylinder head (1a, 2b) are arranged, wherein the high pressure line (9; 9', 9 '') for connecting the respective associated pressure chambers (6a , 6b) durc h the pump cylinder heads (2a, 2b) and the housing (1; 1'; 1 '') runs.

Description

State of the art

The The invention relates to a high pressure fuel pump for a Internal combustion engine, comprising one, rotatable in a housing mounted drive shaft, which in rotation over at least a drive element sets at least two pump elements in motion, wherein by the movement of the at least two pump elements in each case associated pressure chambers fuel intake, at high pressure can be compressed and conveyed into a high-pressure line, which at the same time forms a high-pressure accumulator and with connections for the removal of the fuel is in communication.

From the DE 101 15 859 A1 is such a high-pressure fuel pump is known in which via one, rotatably mounted in a housing drive shaft, two in the axial direction along the drive shaft arranged pump elements are each operable over, provided on the drive shaft drive elements. The pump elements are guided displaceably in a common pump cylinder head, which is placed on the housing. A rotational movement of the drive shaft is converted via the drive elements respectively in translational up and down movements of the pump elements, being sucked in respectively above the pump elements and placed in the pump cylinder head pressure chambers at a downward movement of the respective pump element fuel and compressed in the subsequent upward movement to high pressure. Here, the drive elements are arranged on the drive shaft, that always takes place alternately a high-pressure fuel production by the two pump elements. The high-pressure fuel is conveyed starting from the pressure chambers in a common, running in the pump cylinder head high-pressure line, which serves to store the fuel and from which via connections the fuel is removable.

Indeed such an embodiment of a high-pressure fuel pump is characterized due to the placement of the pump elements along the drive shaft, and the arrangement of the high pressure line by a large axial space requirement. Depending on prevailing space conditions However, in the field of internal combustion engine, this leads to space problems.

It Therefore, the object of the present invention is a high pressure fuel pump with an integrated high-pressure accumulator available to ask, which is due to a small footprint in the axial Direction distinguishes.

These The object is based on the preamble of claim 1 in conjunction solved with its characterizing features. The on it the following, dependent claims respectively advantageous developments of the invention again.

The Invention includes the technical teaching that at least two pump elements Placed in a plane around the drive shaft and in each case a, mounted on the housing pump cylinder head are arranged guided, wherein the high pressure line to Connection of the respective pressure chambers of the pump elements through the pump cylinder heads and the housing runs.

Advantages of the invention

By the inventive arrangement of the pump elements and the high-pressure line makes it possible for the high-pressure fuel pump very compact in axial form. In addition, by the placement the high-pressure line and the length defined with it sufficient storage volume are formed.

According to one Embodiment of the invention are the connections for removing the fuel under high pressure at the respective pump cylinder heads and / or the housing. This has the advantage that the connections according to the number of to be supplied Fuel injectors and depending on the prevailing space conditions can be placed very flexibly along the high pressure line.

In Development of the invention is the high pressure line with a Pressure sensor in conjunction, which integrates into the housing is. In this way, the prevailing fuel pressure reliably and space-savingly monitored in the high pressure line become.

Corresponding an advantageous embodiment of the invention the connections each have throttle points. Through this Measure the high-pressure line before the action of pressure waves protected from the feed lines of the fuel injectors become.

It is a further embodiment of the invention that at least a drive elements is designed as a polygon, which on a Eccentric of the drive shaft is placed. Advantageously, can This in a simple way, the rotational movement of the Drive shaft converted into translational movements of the pump elements become.

According to a further advantageous embodiment of the invention are between the zugehö Pump-cylinder heads and the housing, provided in the high-pressure line each high-pressure seals. By this measure, the transition of the high-pressure line from the housing into the respective pump cylinder head can be reliably sealed and accordingly a leakage of fuel can be effectively prevented at these locations.

Brief description of the drawings

Further, The measures improving the invention will be described below together with the description of preferred embodiments of the invention with reference to the figures shown in more detail.

It shows:

1 a highly schematic view of the high pressure fuel pump according to the invention according to a first embodiment;

2 a sectional view of the high-pressure fuel pump according to the invention 1 orthogonally cut to a longitudinal center axis of a drive shaft;

3 a highly schematic view of the high pressure fuel pump according to the invention according to a second embodiment; and

4 a highly schematic view of the high pressure fuel pump according to the invention according to a third embodiment.

Embodiments of the invention

In 1 is a highly schematic view of the high pressure fuel pump according to the invention according to a first embodiment. This high pressure fuel pump has a housing 1 on which two pump cylinder heads 2a and 2 B are set up. As seen from the sectional view in 2 is apparent in the pump cylinder heads 2a and 2 B , each pump elements 3a and 3b slidably guided, at their, the housing 1 facing end with a common drive element 4 a pump camshaft 5 stay in contact. This drive element 4 is here designed as a polygon, which on an eccentric of the drive shaft 5 is attached. Accordingly, a rotation of the drive shaft 5 in each translational up and down movements of the pump elements 3a and 3b implemented. Above each pump element 3a and 3b is also a pressure room 6a and 6b in the respective pump cylinder head 2a respectively. 2 B provided in which in a downward movement of the respectively associated pump element 3a respectively. 3b Fuel via a low pressure inlet 7 aspirated and in a subsequent upward movement of the pump element 3a respectively. 3b is compressed to high pressure. This high pressure fuel will subsequently overflow in the pump cylinder heads 2a and 2 B provided check valves 8a and 8b in a common high pressure line 9 promoted. The high pressure line 9 runs through the case 1 to the two pressure chambers 6a and 6b by means of check valves 8a and 8b to connect with each other, and also serves as a high-pressure accumulator. For removing fuel from the high pressure line 9 are closing screws of the check valves 8a and 8b each as connections 10a and 10b formed at which in the further course connecting lines can be connected to fuel injectors. In front of these connections 10a and 10b are also throttle points 11a and 11b provided by which in each case the effects of pressure waves from the supply lines of the fuel injectors to the high-pressure line 9 is prevented. Furthermore, in the case 1 a pressure sensor 12 provided with the high pressure line 9 in connection and over which of the prevailing fuel pressure is controllable. Finally, between housing 1 and the pump cylinder heads 2a and 2 B , in the area of the high pressure line 9 each high pressure seals 13a and 13b placed, through which a leakage of fuel into the spaces between housing 1 and pump cylinder head 2a respectively. 2 B can be effectively prevented.

When operating the high-pressure fuel pump, the pump elements 3a and 3b via the drive element 4 according to a rotation of the drive shaft 5 moved in translation, with an alternating filling of the high pressure line 9 over the pressure chambers 6a and 6b with high-pressure fuel. This fuel can then be delivered through the ports 10a and 10b be supplied by means of supply lines to the fuel injectors.

In 3 is a highly schematic view of a second embodiment of the high-pressure fuel pump according to the invention to see. In contrast to the previously described embodiment, the high pressure line 9 ' in this case, over one, the case 1' continuous branch, at the end of another connection 10c is provided. Thus, in this case, three fuel injectors can be supplied via the high pressure fuel pump. The skilled person will, however, be clear that also a corresponding adjustment of the drive element 4 must be made to steadily ensure adequate filling of the high pressure line 9 ' to ensure with fuel.

Finally, in 4 a further, third embodiment of the invention Hoch Pressure fuel pump using a further, highly schematic view to recognize. In this case has a high pressure line 9 '' over another branch in the housing 1'' with a connection 10d at its end, so that a total of four fuel injectors can be supplied.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 10115859 A1 [0002]

Claims (7)

High-pressure fuel pump for an internal combustion engine, comprising a, in a housing ( 1 ; 1'; 1'' ) rotatably mounted drive shaft ( 5 ), which in rotation via at least one drive element ( 4 ) at least two pump elements ( 3a . 3b ) is set in motion, wherein by the movement of the at least two pump elements ( 3a . 3b ) in respectively assigned pressure chambers ( 6a . 6b ) Fuel can be sucked in, compressed to high pressure and into a high-pressure line ( 9 ; 9 '; 9 '' ), which at the same time forms a high-pressure accumulator and with connections ( 10a . 10b ; 10a - 10c ; 10a - 10d ) is connected to the removal of the fuel, characterized in that the at least two pump elements ( 3a . 3b ) in a plane around the drive shaft ( 5 ) and in each case, on the housing ( 1 ; 1'; 1'' ) attached pump cylinder head ( 2a . 2 B ) are arranged, wherein the high pressure line ( 9 ; 9 '; 9 '' ) for connecting the respective associated pressure chambers ( 6a . 6b ) through the pump cylinder heads ( 2a . 2 B ) and the housing ( 1 ; 1'; 1'' ) runs. High-pressure fuel pump according to claim 1, characterized in that the connections ( 10a . 10b ; 10a - 10c ; 10a - 10d ) at the respective pump cylinder heads ( 2a . 2 B ) and / or the housing ( 1'; 1'' ) are provided. High-pressure fuel pump according to claim 1 or 2, characterized in that the high-pressure line ( 9 ; 9 '; 9 '' ) with a pressure sensor ( 12 ), which is in the housing ( 1 ; 1'; 1'' ) is integrated. High-pressure fuel pump according to one of claims 1 to 3, characterized in that the connections ( 10a . 10b ) each throttle restriction ( 11a . 11b ) exhibit. High-pressure fuel pump according to one of the preceding claims, characterized in that the at least one drive element ( 4 ) is designed as a polygon, which on an eccentric of the drive shaft ( 5 ) is attached. High-pressure fuel pump according to one of the preceding claims, characterized in that between the associated pump cylinder heads ( 2a . 2 B ) and the housing ( 1 ), in the area of the high pressure line ( 9 ) each high pressure seals ( 13a . 13b ) are provided. Internal combustion engine with a fuel injection system, comprising a high-pressure fuel pump according to one of the claims 1 to 6.