DE102009027273A1 - High-pressure pump for fuel injection device of internal-combustion engine of common-rail-system of passenger car, has pump element including pump piston that is partially arranged in cylinder head, which is formed as multipart - Google Patents

Abstract

The pump (1) has a housing (2) and a pump element (6) including a pump piston (7) that is partially arranged in a cylinder head (5), where the cylinder head is formed as a multipart. The cylinder head is formed from two housing parts (26, 27), where one of the parts is made of a high pressure-resistant material, and the other housing part is formed as a flange, which is screwed with the housing. The pump piston is partially arranged in the former housing part. An outlet valve (15) is screwed in the latter housing part. An inlet valve (12) e.g. suction valve, is arranged in the cylinder head.

Description

The The present invention relates to a high pressure pump for a fuel injection device of an internal combustion engine according to the Preamble of claim 1.

State of the art

In Fuel injection system like common rail systems for Passenger cars are used high pressure pumps to fuel to pressurize with high pressure. In this case, the high-pressure pump is fuel supplied from a fuel tank. The fuel is over a suction valve to one or more of a pump piston having pump element / s supplied and the pump piston is by the rotational movement a drive shaft indirectly z. B. via a cam or an eccentric in a stroke movement. This is the fuel in a pressure stroke of the pump piston in a pump working space below High pressure set. The high-pressure fuel is then fed via an exhaust valve to a fuel tank and from there to the injectors of the common rail system.

Radial piston pumps, which can be used for this purpose, a housing have, for example, made of aluminum, and the only with low pressure is applied. The pump elements are against each arranged in a high-pressure-resistant cylinder head, due to the prevailing high pressures, for example, from high pressure resistant Steel is made.

In DE 10 2007 029 965 A1 an arrangement of a high-pressure fuel pump is described, the pump interior is formed by a cylinder head of the internal combustion engine, a pump housing and a pump cylinder head. In the pump cylinder head, a suction valve and a movable piston are arranged. The pump cylinder head, the suction valve and the piston together form the high-pressure chamber of the high-pressure fuel pump. In addition, the high-pressure fuel pump is connected to a low pressure circuit and a high pressure circuit.

In order to achieve the largest possible wall thickness in the area of the pressure chambers is beyond DE 195 41 507 A1 a fuel injection device for internal combustion engines with a high-pressure pump is known, the pump working space on the suction side via a delivery line to a fuel tank and the pressure side via a high-pressure line with a high-pressure accumulator is connected from the discharge a plurality of injection lines to the individual injection valves, wherein in each case a pressure valve in the delivery line and in the high pressure line are arranged. The pressure valves of the delivery line and the high pressure line are arranged axially behind one another in a common valve assembly.

The However, known from the prior art high-pressure pumps are In the production very expensive, since that for the high pressure area The high pressure pump material used is a very high quality and therefore very expensive material. In particular, for the Cylinder heads used a high pressure resistant material, what in the production of high-pressure pump leads to high material costs.

Therefore it is necessary to have a high pressure pump for a fuel injector to provide an internal combustion engine, at a lower cost can be produced.

Disclosure of the invention

Advantages of the invention

According to the invention a high pressure pump for a fuel injector an internal combustion engine, in particular for a common rail system, provided, which a housing and at least one cylinder head wherein in the cylinder head a pump piston having a Pump element is at least partially disposed, and wherein the Cylinder head is formed in several parts. Due to the multipart training the cylinder head can advantageously a separation of Functions can be achieved and the high pressure area can be isolated become. In particular, in the cylinder head of the low-pressure inlet of the high pressure areas are separated, which is a high pressure resistant Require material. Only the area of the cylinder head, the is exposed to high pressures, is made of a housing part constructed, which consists of a high pressure resistant material. The remaining Areas of the cylinder head to which no high pressure strength requirements are made are from a separate separate housing part built, made of a less expensive material is. Thus, by the multi-part design of the cylinder head a significant cost reduction in terms of the material can be achieved.

According to one preferred embodiment, the cylinder head is made of a first housing part and a second housing part constructed, with only the first housing part of a high pressure resistant material is constructed. The second housing part can be constructed of a non-high pressure resistant material, which is more cost effective, reducing the overall manufacturing costs the high-pressure pump can be reduced.

According to A preferred embodiment is the pump piston at least partially disposed in the first housing part. Since the pump piston is assigned to the high pressure area, in which certain requirements regarding the high pressure resistance of the material are placed, this is advantageously arranged in the first housing part, which is made of the high pressure resistant material.

According to Another preferred embodiment is the second one Housing part designed as a flange, which with the housing connectable, in particular screwed on, is. By this embodiment it is also possible the orientation of the high pressure port to twist with the flange when the low pressure port adjusted is executed or as Teilringnut.

Preferably is provided in the second housing part, an outlet valve, screwed in particular. Preferably, the outlet valve is a check valve.

According to one Another preferred embodiment is in the cylinder head an inlet valve, in particular a suction valve arranged.

According to Another preferred embodiment, the cylinder head a third housing part. This allows a even more separation of functions.

Especially Preferably, the third housing part is a closure element educated.

According to one preferred embodiment, the third housing part a connection over which the third housing part can be connected to a high-pressure accumulator.

According to one Another preferred embodiment is the third housing part itself formed as a high-pressure accumulator.

Preferably the third housing part has an interior, which a storage volume for high-pressure fuel forms. This embodiment is through the integration of the high-pressure accumulator in the closure element or in the third Housing part particularly space-saving.

Yet it is more preferable if the third housing part at least having a high pressure outlet through which high pressure fuel is forwarded to an injector.

Also It is particularly preferred if in the cylinder head a first Valve and a second valve are provided, wherein the first valve and the second valve axially behind one another, in particular in one In-line arrangement are arranged. This is a special one space-saving arrangement. On the other hand, offers the in-line arrangement the valves advantages in terms of high-pressure tightness, as a result, an interface between the high pressure valve and the two-piece cylinder head is avoided.

Preferably the first valve is the inlet valve.

According to A preferred embodiment is the second valve the exhaust valve, through which high-pressure fuel the high-pressure accumulator, in particular the interior in the third Housing part, is supplied.

Brief description of the drawings

in the Below are embodiments of the invention with reference to the accompanying drawings described. It shows:

1 a partial sectional view through a high pressure pump according to the prior art;

2 a section through a high-pressure pump according to an embodiment;

3 a section through a high-pressure pump according to an embodiment;

4 a section through a high-pressure pump according to an embodiment;

5A a detailed view of a section of 4 ;

5B another detail view of a section of 4 ;

6A a detailed view of a section of 4 ;

6B a respect 6A 90 ° rotated detail view of the section of 4 ;

7 a section through a high-pressure pump according to an embodiment;

8th a detailed view of a third housing part;

9A . 9B and 9C respective plan views of a third housing part; and

10A and 10B respective Schnittan sift through a third housing part.

embodiments the invention

In 1 is a high pressure pump 1 for a fuel injection device of an internal combustion engine according to the prior art. The high pressure pump 1 According to the prior art has a housing 2 in which a rotationally driven drive shaft 3 is arranged, on which a cam 4 is provided. The high pressure pump 1 indicates in a cylinder head 5 arranged pump element 6 with a pump piston 7 on that by the cam 4 the drive shaft 3 indirectly in a lifting movement in at least approximately radial direction to the axis of rotation D of the drive shaft 3 is driven. The pump piston 7 is in a cylinder bore 8th in the cylinder head 5 guided tightly displaceable and limited with its the drive shaft 3 opposite end face in the cylinder bore 8th a pump workroom 9 , At his the pump workroom 9 opposite end, the pump piston 7 an enlarged in diameter over its remaining area piston foot 19 on.

As can be seen in the figure, the cylinder head 5 with a shaft section 10 provided in which the pump piston 7 receiving cylinder bore 8th is provided, and around which the spring 11 is arranged.

The pump workroom 9 has one in the housing 2 extending fuel inlet channel (not shown) to connect to a fuel inlet, for example, a feed pump. At the mouth of the fuel inlet duct into the pump workspace 9 is one in the pump work space 9 opening inlet valve 12 arranged, which is a spring-loaded valve member 13 having. The pump workroom 9 also has one in the cylinder head 5 extending fuel drain channel 14 a connection to an outlet, which is connected for example to a high-pressure accumulator (not shown) of a common rail system. One or preferably a plurality of injectors (not shown) arranged on the cylinders of the internal combustion engine are connected to the high-pressure accumulator, through which fuel is injected into the cylinders of the internal combustion engine. At the mouth of the fuel drainage channel 14 into the pump workroom 9 is one out of the pump workroom 9 opening exhaust valve 15 arranged.

The pump element 6 is a ram assembly with a hollow cylindrical roller tappet 16 , a roller shoe 17 and a roller 18 assigned over which the pump piston 7 on the cam 4 the drive shaft 3 supported. The plunger assembly and the pump piston 7 be through the preloaded spring 11 to the cam 4 the drive shaft 3 pressed down. The feather 11 is as the pump piston 7 formed surrounding coil spring. The feather 11 supported on the one hand on a housing wall of the cylinder head 5 and on the other hand on a spring plate 20 from.

The spring plate 20 is with the pump piston 7 connected so that the spring 11 both on the pump piston 7 as well as on the roller plunger 16 acts against these against the cam 4 the drive shaft 3 to press. The described high pressure pump 1 According to the prior art does not lead high pressure within the housing 2 , so no high pressure or strength enhancing measures for the housing 2 required are.

Furthermore, in 1 recognizable that the high pressure pump 1 a metering unit 23 and that on the housing 2 a mounting flange 24 is available.

2 shows a section through a high-pressure pump 1 according to an embodiment in the region of the cylinder head 5 , The high pressure pump 1 has a housing 2 on, in which a not shown here engine is arranged with a drive shaft. In a recess 25 in the case 2 , which is formed as a cylindrical bore, is a multipart cylinder head 5 taken on which a first housing part 26 and a second housing part 27 having. In the first housing part 26 , which is made of high pressure resistant material and which receives the components exposed to high pressure, is the pump piston 7 of the pump element 6 arranged and the pump work space 9 formed from which high-pressure fuel via a funnel-shaped to an exhaust valve 15 opening fuel drain channel 14 is forwarded. The outlet valve 15 , which is not shown in detail here, is designed as a check valve high-pressure valve and as an independent component in a pressure pipe socket 29 in the second housing part 27 arranged. In the embodiment, the check valve is in the funnel-shaped portion 28 of the fuel drain channel 14 screwed in and pressed there. Between the first housing part 26 and the housing 2 is in the recess 25 in addition a spring 11 arranged.

The second housing part 27 is formed as a flange, in which a fuel inlet channel 30 is provided, via which the pump element 6 Fuel is supplied from a fuel tank, not shown. The fuel inlet channel 30 leads to a likewise in the second housing part 27 provided inlet valve 12 , which is designed as a suction valve. The suction valve is in the second housing part 27 of the cylinder head 5 either screwed or pressed. The second housing part 27 , which is not exposed to high pressures, is made of a material which does not have the special high-pressure resistance and therefore is less expensive than the material from which the first housing part 26 is made.

3 shows a section through a high-pressure pump 1 according to another embodiment in the region of the cylinder head 5 which differ from the in 2 embodiment shown essentially by the formation of the first housing part 26 and the second housing part 27 different. In this case, the first housing part 26 again made of a high pressure resistant material and takes the pump element 6 with the pump piston 7 on. In addition, are also in the first housing part 26 the pump work space 9 and the fuel drain passage 14 educated. Unlike the in 2 the embodiment shown takes the first housing part 26 beyond that also the inlet valve 12 , which is designed as a suction valve on. The second housing part 27 is made of a less expensive material than the first housing part 26 Herge poses, as it is not the case for the first housing part 26 required high pressure resistance must have. The second housing part 27 surrounds the first housing part 26 in at least one section. In the second housing part are the fuel inlet channel 30 and a pressure pipe socket 29 provided in which the exhaust valve 15 , which is designed as a check valve, is pressed or screwed.

4 shows a section through another embodiment of a high-pressure pump 1 in the area of the cylinder head 5 , In this embodiment, the high-pressure tightness by an axial arrangement of the valves, namely a first valve, which is formed by the inlet valve designed as a suction valve 12 is formed, and a second valve, which by the outlet valve designed as a check valve 15 is formed, according to the so-called in-line concept improved. Also in this embodiment, the cylinder head 5 from a first housing part 26 , which receives the high pressure components and is made of high pressure resistant material, and a second, designed as a flange housing part 27 constructed, which is not made of a high pressure resistant material. The second housing part 27 is to the case 2 the high pressure pump 1 screwed.

At the in 2 and 3 the embodiments shown is the exhaust valve 15 in the flange or in the second housing part 27 screwed and seated in the first housing part 26 pressed. In this configuration, the tightness between the exhaust valve 15 and the first and second housing parts 26 . 27 of the cylinder head 5 relatively complex. The cylinder head 5 must be well positioned in this configuration and additionally oriented during assembly to ensure good positioning and a good sealing point with the exhaust valve 15 to ensure. Due to the in-line arrangement of the inlet valve 12 and the exhaust valve 15 axially behind one another, this problem is avoided and a good high pressure tightness ensured.

According to the in 4 illustrated embodiment is also in the second housing part designed as a flange 27 the inlet hole 30 provided, through which fuel flows and into an annulus 32 empties. A valve holder 33 is in the second housing part 27 mounted and is by a third housing part 31 , which is designed as a closure element held. Two axial bores 34 are on the circumference of the valve holder 33 formed and allow a connection to the inlet valve designed as a suction valve 12 , The inlet valve 12 consists of a sphere 35 , a valve field 36 and a penholder 37 in the valve holder 33 is pressed. Two holes (not shown) are in the spring holder 37 formed to connect to the pump workspace 9 to enable. The compressed fuel may, as in the previously described embodiments, through the exhaust valve 15 , which acts as a high pressure valve, be forwarded to a fuel storage of the common rail system. In the valve holder 33 are for passing the high pressure fuel to the exhaust valve 15 drilling 38 intended. A valve piston 39 is in the to the end of the valve holder 33 in which the inlet valve 12 is received, opposite end of the valve holder 33 added. A valve spring 40 is in the third housing part 31 arranged to the desired opening pressure of the exhaust valve 15 provided. The third housing part designed as a closure element 31 has a central hole 41 on, which serves as a connection to a high-pressure accumulator.

In 5A and 5B are the in 4 not shown in detail holes, which in the pen holder 37 are provided to allow the fuel into the pump working space 9 to flow, showing the holes 42 in 5A as through holes and in 5B are formed as slots.

6A shows in detail the arrangement of the holes 38 in the valve holder 33 , which provides fluid communication of the fuel between the pump working space 9 and the exhaust valve 15 enable. 6B shows a reference 6A 90 ° about the longitudinal axis L of the pump piston 7 rotated detail view, in which the arrangement of the axial bores 34 at the periphery of the valve neck ters 33 what is shown is the connection of the annulus 32 to the inlet valve 12 allows.

7 shows a section through a high-pressure pump 1 according to another embodiment in the region of the cylinder head 5 , Again, the cylinder head 5 in several parts with a first housing part 26 for the high pressure components, a second formed as a flange housing part 27 and a third housing part designed as a closure element 31 built up. Also, as already related to 4 described embodiment, an in-line arrangement of the inlet valve 12 and the exhaust valve 15 realized axially one behind the other. In the 7 However, the embodiment shown differs from that in 4 shown embodiment in the area or by the configuration of the third housing part 31 , Unlike the in 4 embodiment illustrated takes over the third housing part 31 in this embodiment, a memory function, since here the high-pressure accumulator in the third housing part 31 is integrated, and also has a distribution function by providing high-pressure outputs 43 to the injectors of the common rail system, not shown here.

The by the lifting movement or by the pressure stroke of the pump piston 7 compressed fuel is in this embodiment by the outlet valve designed as a check valve 15 to one in the third housing part 31 formed interior 44 directed. The fuel flows from the pump working space 9 through the in the valve holder 37 trained holes 38 to go to the exhaust valve 15 to get. The internal geometry or internal space 44 of the third housing part designed as a closure element 31 defines a storage volume for the fuel, so that in this embodiment, the third housing part 31 the rail function takes over. From the interior 44 perform central drilling 41 to respective high pressure outputs 43 which can be connected to respective injectors (not shown). By this configuration, several applications are covered in a simple manner, only by the configuration of the third housing part 31 The high-pressure pump, for example, for use in three-cylinder or two-cylinder engines, etc. can be adjusted.

8th shows a detailed view of the third housing part 31 , which at its outer periphery with a threaded portion 45 is provided to the second housing part 37 to be screwed. Also present in this embodiment, two high-pressure outputs 43 have respective threaded sections 46 to be connectable with injectors or high pressure lines.

9A . 9B and 9C show respective plan views of the third housing part 31 , In the in 9A the embodiment shown is the third housing part 31 with two high-pressure outputs 43 equipped, whereas in the 9B illustrated embodiment, three high-pressure outputs 43 and in the in 9C illustrated embodiment, four high-pressure outputs 43 in the third housing part designed as a closure element 31 are provided.

10A and 10B Finally, show two different embodiments with respect to the arrangement of the high pressure outputs 43 in the third housing part 31 , where the high pressure outputs 43 in 10A radially from the interior 44 depart or radially from an outer wall 47 of the third housing part 31 protrude. According to the in 10B The embodiment shown is a central high-pressure outlet 43 arranged axially and two more high-pressure outputs 43 are arranged at an angle α.

The high pressure pump 1 showing the split cylinder head 5 According to the above embodiments, offers a space-saving and cost-effective concept and also has a good high pressure tightness.

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 102007029965 A1 [0004]
• - DE 19541507 A1 [0005]

Claims (15)

High pressure pump ( 1 ) for a fuel injection device of an internal combustion engine, in particular for a common rail system, which has a housing ( 2 ) and at least one cylinder head ( 5 ), wherein in the cylinder head ( 5 ) a pump piston ( 7 ) having a pump element ( 6 ) is at least partially arranged, characterized in that the cylinder head ( 5 ) is formed in several parts. High pressure pump ( 1 ) according to claim 1, characterized in that the cylinder head ( 5 ) from a first housing part ( 26 ) and a second housing part ( 27 ), wherein only the first housing part ( 27 ) is made of a high pressure resistant material. High pressure pump ( 1 ) according to claim 1 or 2, characterized in that the pump piston ( 7 ) at least partially in the first housing part ( 26 ) is arranged. High pressure pump ( 1 ) according to one or more of claims 1 to 3, characterized in that the second housing part ( 27 ) is formed as a flange, which with the housing ( 2 ) connectable, in particular screwed, is. High pressure pump ( 1 ) according to one or more of claims 1 to 4, characterized in that in the second housing part ( 27 ) an exhaust valve ( 15 ) is provided, in particular screwed, is. High pressure pump ( 1 ) according to one or more of claims 1 to 5, characterized in that in the cylinder head ( 5 ) an inlet valve ( 12 ), in particular a suction valve, is arranged. High pressure pump ( 1 ) according to one or more of claims 1 to 6, characterized in that the cylinder head ( 5 ) a third housing part ( 31 ) having. High pressure pump ( 1 ) according to claim 7, characterized in that the third housing part ( 31 ) is designed as a closure element. High pressure pump ( 1 ) according to claim 7 or 8, characterized in that the third housing part ( 31 ) has a connection via which the closure element can be connected to a high-pressure accumulator. High pressure pump ( 1 ) according to one or more of claims 7 to 9, characterized in that the third housing part ( 31 ) is designed as a high-pressure accumulator. High pressure pump ( 1 ) according to one or more of claims 7 to 10, characterized in that the third housing part ( 31 ) an interior ( 44 ), which forms a storage volume for high-pressure fuel. High pressure pump ( 1 ) according to one or more of claims 7 to 11, characterized in that the third housing part ( 31 ) at least one high-pressure outlet ( 43 ), through which high-pressure fuel is passed on to an injector. High pressure pump ( 1 ) according to one or more of claims 1 to 12, characterized in that in the cylinder head ( 5 ), a first valve and a second valve are provided, wherein the first valve and the second valve are arranged axially behind one another, in particular in an in-line arrangement. High pressure pump ( 1 ) according to one or more of claims 6 to 13, characterized in that the first valve, the inlet valve ( 12 ). High pressure pump ( 1 ) according to one or more of claims 5 to 14, characterized in that the second valve, the exhaust valve ( 15 ) is, by which high-pressure fuel to a high-pressure accumulator, in particular the interior ( 44 ) in the third housing part ( 31 ) is supplied.