DE102008001587A1 - High pressure fuel pump for operating an internal combustion engine - Google Patents

Abstract

The invention relates to a high-pressure fuel pump for operating an internal combustion engine having a pump housing (1) in which at least two pump pistons, which are in contact with a pump camshaft mounted in the middle of the pump housing (1), are displaceably guided in piston bores (2a to 2c) and on each of which above the piston bores (2a to 2c) a pump cylinder head (4a to 4c, 4a 'to 4c') is placed, wherein above the at least two pump pistons in the respective pump cylinder head (4a to 4c, 4a 'to 4c') each one Pressure chamber is arranged, in which upon movement of the respective pump piston via a respective suction valve (9) fuel is sucked and then compressible to high pressure, wherein the fuel under high pressure of the pressure chambers via high pressure valves and high pressure lines (6, 7) in a common high pressure port (10 ) is merge, and further the merger of the high pressure Fuel and the high pressure port (10) in one of the at least two pump cylinder heads (4a; 4a ') are placed.

Description

The The invention relates to a high pressure fuel pump for operating a Internal combustion engine with a pump housing, in which at least two pump pistons, which with one in the middle of the Pump housing stored pump camshaft in contact are guided, slidably guided in piston bores and on each of which a pump cylinder head is placed above the piston bores is, wherein above the at least two pump pistons, in the respective Pump cylinder head each a pressure chamber is arranged, in which upon movement of the respective pump piston via each a suction fuel suctionable and then on High pressure is compressible, with the high pressure fuel the pressure chambers via high pressure valves and high pressure lines in a common high-pressure connection zusammenführbar is.

State of the art

From the DE 42 13 781 C2 already a high-pressure fuel pump for internal combustion engines is known, in which three pump pistons are arranged at 120 ° to each other in a pump housing. These pump pistons are driven via a pump camshaft mounted in the pump housing by means of a common cam. Through this contact between the cam and the respective pump piston, a rotation of the pump camshaft is converted into a translational movement of the respective pump piston, resulting in arranged on the pump housing pump cylinder heads and arranged above the respective pump piston pressure chambers to a suction of fuel and subsequent compression. The compressed high pressure fuel is then passed to a high pressure port in the pump cylinder head through which the high pressure fuel pump is in contact with a high pressure accumulator of the engine. However, in this case also a merger of the high-pressure lines of the individual pump cylinder heads in the pump housing to a common high-pressure connection is common.

disadvantageous Known in the prior art is that such a merger of the High-pressure lines intersections in the pump housing arise, which due to a low pressure resistance of the pump housing lead to a restriction of the pressure of the fuel.

It Therefore, the object of the present invention is a high pressure fuel pump to provide at which a higher high pressure resistance is reached.

Disclosure of the invention

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

The Invention includes the technical teaching that a merger of the high pressure fuel and the high pressure port in one of the pump cylinder heads are placed. The pump cylinder heads show due to the fact that it is hardened Components acts, higher strength, so that Intersections and the placement of the high pressure port in this Impact area lower impact.

According to one open further advantageous embodiment of the invention the high pressure lines in the high pressure port having the pump cylinder head eccentric in a high pressure valve bore, which in the further History communicates with the high pressure port. By the eccentric This can lead to high pressure resistance in this area be further increased while summarizing the High pressure lines of the individual pump cylinder heads in Range of high pressure valve hole represents a compact design.

In Further development of the invention, the at least two pump cylinder heads over Metal seals with Siggen in the area of high-pressure lines opposite sealed to the pump housing. In this way becomes a reliable seal of the high pressure lines in the area of the contact surface between the pump housing and reached the respective pump cylinder head.

According to one Further advantageous embodiment of the invention are in use of two pump pistons opposite the pump cylinder heads arranged while connecting the two pump cylinder heads the high pressure line through the pump housing in the area a small diameter bearing of the pump camshaft is guided. This has the advantage that the high pressure line just passed through the pump housing and therefore no overlap in the area of the pump camshaft created in the pump housing.

In a further development of the invention, the pump cylinder heads are arranged at a 120 ° angle to each other when using three pump pistons, of which in a pump cylinder head, the high pressure lines for connection with the other two eccentrically in the high pressure valve bore to connect to the common high-pressure connection. In this way, in a fuel pump with three pump pistons, a summary of the high pressure fuel can be achieved in terms of optimal high pressure resistance.

According to one Another embodiment of the invention, the pump cylinder heads all two connections for high pressure lines on, wherein at the pump cylinder heads, in which not the high pressure port is placed, a connection closed by the pump housing is. This has the advantage that for all pump cylinder heads the same components can be used, the second line but only in the pump cylinder head comes into play, in which the high-pressure connection is placed.

In Further development of the invention are the high pressure lines respectively perpendicular to the contact surface with the pump housing in led the pump cylinder heads. In this manner and way the sealed cross-section can be kept small.

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.

Brief description of the drawings

It shows:

1 a sectional view of the high-pressure fuel pump according to the invention according to a first embodiment;

2 a sectional view cut along the line AA in 1 ;

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

4 a sectional view cut along the line BB in 3 ,

Detailed description the drawings

In 1 is a sectional view of the high-pressure fuel pump according to the invention according to a first embodiment to see, which via a pump housing 1 has, in which three, in a 120 ° angle to each other arranged piston bores 2a to 2c are provided. Moreover, in the middle of the pump housing 1 a hole 3 placed for a pump camshaft, not shown here. Above each piston bore 2a to 2c is each a pump cylinder head 4a to 4c on the pump housing 1 placed. The pump cylinder heads 4a to 4c each have a high pressure valve bore 5a to 5c , in each of which a high-pressure valve is placed, to which the compressed fuel is conveyed during an upward movement of the respective pump piston. These high pressure valve holes 5a to 5c each have two eccentric connection lines, which to the respective bottom surface of the pump cylinder head 4a to 4c to lead. About these lines is the high pressure valve bore 5a the pump cylinder head 4a on the one hand by means of a pump housing 1 arranged high pressure line 6 with the high pressure valve hole 5c the pump cylinder head 4c and on the other hand by means of a high-pressure line 7 , which also in the pump housing 1 is arranged with the high pressure valve bore 5b the pump cylinder head 4b in connection. In addition, to prevent leakage of the high pressure fuel, are between the pump cylinder heads 4a to 4c and the pump housing 1 Metal seals with siggers 8a to 8c arranged. In the 2 is a sectional view of the pump cylinder head 4a to see along the line AA. From this view, the arrangement of the high pressure valve bore 5a relative to the piston bore 2a seen. In addition, the mutual confluence of the connecting lines to the high pressure lines 6 and 7 starting from the base of the pump cylinder head 4a be recognized. On the high pressure valve bore 5a opposite side of the piston bore 2a is a suction valve 9 arranged over which is sucked at a suction movement of the respective pump piston under low pressure fuel. At the end of the high pressure valve bore 5a is also a high pressure connection 10 provided for connection to a high-pressure accumulator of the internal combustion engine.

Out 3 is a second embodiment of the high-pressure fuel pump according to the invention can be seen. In contrast to the previously described embodiment in this case are the high pressure lines 6 and 7 not in one plane of the pump housing 1 arranged, but lie behind each other. In the pump cylinder heads 4a ' to 4c ' are also the connecting lines to the high pressure lines 6 and 7 perpendicular to the base of the pump cylinder heads 4a ' to 4c ' educated. The confluence of these connecting lines is off 4 which is a sectional view of the pump cylinder head 4a ' along the line BB, seen light. It can be seen that the connecting lines one behind the other in the high-pressure valve bore 5a open out.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 4213781 C2 [0002]

Claims (8)

High-pressure fuel pump for operating an internal combustion engine with a pump housing ( 1 ), in which at least two pump pistons, which with one in the middle of the pump housing ( 1 ) are in contact with the pump camshaft, in piston bores ( 2a - 2c ) are displaceably guided and on which above the piston bores ( 2a - 2c ) each a pump cylinder head ( 4a - 4c ; 4a ' - 4c ' ), wherein above the at least two pump pistons, in the respective pump cylinder head ( 4a - 4c ; 4a ' - 4c ' ) in each case a pressure chamber is arranged, in which upon movement of the respective pump piston via a respective suction valve ( 9 ) Fuel can be sucked in and then compressed to high pressure, wherein the high-pressure fuel of the pressure chambers via high-pressure valves and high-pressure lines ( 6 . 7 ) in a common high-pressure connection ( 10 ), characterized in that the merging of the high pressure fuel and the high pressure port ( 10 ) in one of the at least two pump cylinder heads ( 4a ; 4a ' ) are placed. High-pressure fuel pump according to claim 1, characterized in that the high-pressure lines ( 6 . 7 ) in which the high pressure port ( 10 ) having a pump cylinder head ( 4a ; 4a ' ) eccentrically in a high pressure valve bore ( 5a ), which in the further course with the high-pressure connection ( 10 ). High-pressure fuel pump according to claim 1 or 2, characterized in that the at least two pump cylinder heads ( 4a - 4c ; 4a ' - 4c ' ) about metal seals with Siggen ( 8a - 8c ) in the area of high-pressure lines ( 6 . 7 ) relative to the pump housing ( 1 ) are sealed. High-pressure fuel pump according to one of claims 1-3, characterized in that when using two pump pistons, the pump cylinder heads ( 4a - 4c ; 4a ' - 4c ' ) are arranged opposite one another and that for connecting the two pump cylinder heads ( 4a - 4c ; 4a ' - 4c ' ) the high pressure line ( 6 . 7 ) through the pump housing ( 1 ) is passed in the region of a bearing with a small diameter of the pump camshaft. High-pressure fuel pump according to claim 2 or 3, characterized in that when using three pump pistons, the pump cylinder heads ( 4a - 4c ; 4a ' - 4c ' ) are arranged at a 120 ° angle to each other, of which at a pump cylinder head ( 4a ; 4a ' ) the high pressure lines ( 6 . 7 ) for connection with the other two eccentric in the high pressure valve bore ( 5a ) for connection to the common high-pressure connection ( 10 ). High-pressure fuel pump according to claim 5, characterized in that the pump cylinder heads ( 4a - 4c ) all two connections for high-pressure lines ( 6 . 7 ), wherein at the pump cylinder heads ( 4b . 4c ), in which not the high-pressure connection ( 10 ), a connection through the pump housing ( 1 ) is closed. High-pressure fuel pump according to one of the preceding claims, characterized in that the high-pressure lines ( 6 . 7 ) each perpendicular to the contact surface with the pump housing ( 1 ) into the pump cylinder heads ( 4a ' - 4c ' ) are guided. Internal combustion engine for operating a motor vehicle, comprising a high-pressure fuel pump according to one of the claims 1-7.