WO2013053593A1

WO2013053593A1 - Two-part cylinder head for a high-pressure fuel pump with integrated non-return valve

Info

Publication number: WO2013053593A1
Application number: PCT/EP2012/068826
Authority: WO
Inventors: Friedrich Boecking
Original assignee: Robert Bosch Gmbh
Priority date: 2011-10-10
Filing date: 2012-09-25
Publication date: 2013-04-18
Also published as: DE102011084193A1

Abstract

The invention relates to a cylinder head (7) for a high-pressure fuel pump (43) of a fuel injection device (1). The cylinder head (7) is hydraulically connected to a high-pressure chamber (9) and has a valve plate (27) that is hydraulically connected to the high-pressure chamber (9). A suction valve (29) and a non-return valve (31) are arranged in a parallel manner in the valve plate (27).

Description

description

Two-piece cylinder head for a high-pressure fuel pump with integrated non-return valve

State of the art

For operating internal combustion engines such. As internal combustion engines, fuel must be transported from a reservoir into the combustion chamber of an internal combustion engine and fed to this control. For this purpose, fuel delivery devices are also known as high-pressure fuel pump, known to provide the fuel under high pressure.

The cylinder head of the fuel delivery devices is hydraulically connected to a high-pressure chamber. In order to withstand the high pressures, the cylinder head is forged in one piece. Valves, e.g. a check valve (RSV) for preventing a fuel return from the high-pressure chamber, are arranged outside the cylinder head, for example behind a suction valve. The operation of the check valves may be suboptimal, if they are far away from the high-pressure generating point of the cylinder head.

Disclosure of the invention

There may therefore be a need for an improved cylinder head and a correspondingly improved fuel delivery device that allow for better functionality of the check valves and, where appropriate, reduce manufacturing costs. This object can be achieved by the subject matter of the present invention according to the independent claims. Advantageous embodiments of the present invention are described in the dependent claims.

In the following, features, details and possible advantages of a device according to embodiments of the invention will be discussed in detail.

According to a first aspect of the invention, a cylinder head for a

High-pressure fuel pump presented a fuel injection device. The cylinder head is hydraulically connected to a high-pressure chamber and has a valve plate, which is also hydraulically connected to the high-pressure chamber. In this case, a suction valve and a check valve are arranged in parallel in the valve plate.

In other words, the idea of the present invention is based on a non-return valve in a multipart cylinder head

Integrate valve plate directly adjacent to a suction valve and this directly on the cylinder head, in particular at the high-pressure generating point of the

Cylinder head to arrange.

The inventive design of the cylinder head allows improved functionality of the check valve, which a backflow of the fuel from the high-pressure chamber more effective than in known

Embodiments prevented. Further, the modular construction of the cylinder head allows easier interchangeability, e.g. the valve plate with the individual valves. Furthermore, manufacturing costs of the cylinder head can be saved because the manufacturing process is simplified by the modular design of the cylinder head.

The cylinder head may be used in high-pressure fuel pumps used in fuel injectors for injecting fuel into a combustion chamber of an internal combustion engine. The corresponding fuel injection devices can be used, for example, in motor vehicles such as cars and in particular in commercial vehicles such as trucks. Furthermore, the cylinder head according to the invention and the corresponding High-pressure fuel pump can be used in systems with fuel pressure accumulator, also referred to as "rail" or common rail injection.

In fuel pressure accumulator systems, fuel, e.g. Gasoline or diesel, by means of a high-pressure fuel pump from a fuel tank, in particular from the fuel tank or a storage pot in a fuel pressure accumulator G.Raü "promoted." There, the fuel is stored under high pressure to the fuel pressure accumulator one or in the In principle, a plurality of fuel injection devices can be connected, which can inject the fuel directly into combustion chambers assigned to them The fuel injection device can be connected to an electronic control unit or to a control unit which regulates the injection time and the injection quantity, for example via an electrically actuated valve ,

The cylinder head is equipped with a high-pressure chamber, especially one

Fuel pressure accumulator hydraulically connected. The cylinder head may have one or more suction and check valves. The cylinder head is arranged on a housing of the high-pressure fuel pump.

In the cylinder head, a valve plate is integrated, in which at least one suction valve and a check valve are incorporated or arranged. The suction valve can suck fuel via an inlet from the fuel tank and a

Feed the working space of the cylinder head. In the working space of the fuel can be compressed by means of a piston and placed under high pressure. If a predeterminable pressure value of the fuel in the working space is reached, the non-return valve hydraulically connected to the working space opens and allows the pressurized fuel to pass into the high-pressure space. One

Backflow of the fuel from the high-pressure chamber is caused by the

Check valve prevents. For this purpose, the check valve may e.g. be designed as a spring-loaded ball valve. Furthermore, the

Check valve as a pressure relief valve, which opens in the direction of the high-pressure chamber to be executed. At the check valve may also be provided a stroke stop.

The check valve is integrated parallel to the suction valve in the valve plate. That is, both valves are arranged spatially parallel to each other. hydraulic However, the valves are considered in series, ie arranged one behind the other. In particular, the check valve is arranged downstream of the suction valve. The valves may be arranged eccentrically in the valve plate. This means that neither the suction valve nor the check valve must be positioned centrally on the valve plate.

According to one exemplary embodiment of the invention, the cylinder head has a first component and a separately manufactured second component. The first component has a first cylindrical cavity, also referred to as a pump working space or as a high-pressure bore. The cavity is used to guide a

Piston or pump piston executed. The first component can be made of hardened material, preferably as a symmetrical rotary component or rotary part, in order to have sufficient high-pressure resistance and to be able to withstand the high pressure in the working space.

The second component is designed separately from the first component and can be made of a different material and with different manufacturing methods than the first component. In particular, the second component is made of simple non-hardened steel. The second component surrounds the first component annularly. In this case, the second component of the attachment of the cylinder head to the housing of the high-pressure fuel pump, for. serve by means of screws. In particular, the second component may be designed as a flange or act as a flange. The valve plate is arranged in a recess of the second component, in which the first component is arranged.

Thanks to the two-part design of the cylinder head, the first component may e.g. be carried out as a forging blank relatively small, which reduces the cost of the cured material. Furthermore, the shape of the first component in

Compared to known designs are simplified, so that the manufacturing costs, for. can be lowered by automating the production. The second component does not have to be hardened and can be made of cheaper material. Thus, the entire

Cost of production of the high-pressure fuel pump and the entire fuel injection device can be significantly reduced. Furthermore, the two-part embodiment of the cylinder head allows the modular design and integration of the valve plate in the cylinder head. According to a further exemplary embodiment of the invention, the first component has an annular step, also referred to as a cylinder head ring. The shoulder has a larger radial dimension in a plane perpendicular to the longitudinal axis of the first component than the remaining first component. That is, the first component has a longitudinal axis, which coincides in particular with the longitudinal axis of the cylindrical cavity in the first component. If sectional planes perpendicular to this longitudinal axis are formed by the first component of the cylinder head, then the cross-sectional area or the radius of the first component in the sectional plane which runs through the shoulder is greatest. The second

Component has a bearing surface, which corresponds in a radial dimension of the radial dimension of the paragraph and is designed to receive the paragraph. The paragraph thus defines together with the contact surface the positioning of the first and the second component in relation to each other. By other elements that are included in the second component and the first

Abut component, the first component can be pressed against the contact surface of the second component.

According to a further exemplary embodiment of the invention, the second component has a second cylindrical cavity, also referred to above as a recess. The longitudinal axis of the second cavity coincides with a

Longitudinal axis of the first cylindrical cavity together. That the second component is optionally arranged concentrically around the first component. The valve plate corresponds in its radial dimension to a radial dimension of the second cylindrical cavity and is arranged in the second cylindrical cavity. That The valve plate can be inserted precisely into the second cavity and rest on the first component.

According to a further embodiment of the invention, a pressure pipe socket is provided on the cylinder head, which corresponds in its radial dimension of the radial dimension of the second cylindrical cavity and is arranged in the second cylindrical cavity. The valve plate is arranged between the first component and the pressure pipe socket. According to a further embodiment of the invention, the pressure pipe socket is designed to engage positively and / or non-positively with the second component and to press the valve plate in the direction of the first component. That is the Pressure pipe socket acts as a clamping element. For this purpose, for example, a thread may be provided in the corresponding region of the second cavity with which an external thread of the pressure pipe socket can engage. In the pressure pipe socket, a recess may be provided which connects the check valve with the high-pressure chamber.

According to a further exemplary embodiment of the invention, the valve plate has a first valve plate element and a separate second valve plate element. The suction valve and the check valve are arranged in the first valve plate element. The second valve plate element has a first one

Recess and a second recess. The first recess hydraulically connects the first cylindrical cavity of the first component to the suction valve, and the second recess connects the first

cylindrical cavity of the first component with the check valve.

According to a further exemplary embodiment of the invention, the valve plate has a separate third valve plate element which has a third recess which connects the check valve to the high-pressure chamber. The first valve plate element is thus arranged between the second and third valve plate element. The radial dimensions of all the valve plate elements are adapted to the radial dimensions of the second cavity. The

Expansion of the valve plate elements in the axial direction may be variable. For example, For example, the axial extent or height of the second valve plate element can be selected such that when the first valve plate element rests on the second valve plate element, provided in the second component

Inlet opening is located exactly at the height of a Saufventileinlasses. The

Recesses in the second and third valve plate element can as

Be carried out drilling. The modular construction of the valve element and also of the cylinder head is advantageous since the production of the individual parts is less complicated and less complicated. Furthermore, the individual parts can be easily replaced if necessary.

According to a further embodiment of the invention, the first

Valve plate element by means of at least one pin with the second

Valve plate element connected. The first valve plate element is further connected by means of at least one pin to the third valve plate element.

That is, the valve plate elements are attached to each other. The pins can be arranged eccentrically to ensure accurate positioning of the valve inlet and outlet with respect to the recesses in the second and third valve plate element. Alternatively, a single pin can be provided which extends through all three valve plate elements and thus enables exact positioning.

According to a second aspect of the invention, a high-pressure fuel pump for a fuel injection device is presented. In this case, the

High-pressure fuel pump on a cylinder head described above.

Other features and advantages of the present invention will become

Expert from the following description of exemplary

Embodiments, which should not be construed as limiting the invention, with reference to the accompanying drawings.

Fig. 1 shows schematically the arrangement of the high-pressure fuel pump with the cylinder head according to the invention between a

Fuel tank and internal combustion engine

Fig. 2 shows a cross section through a section of the

High-pressure fuel pump with two-part cylinder head according to an embodiment of the invention

All figures are merely schematic representations of devices according to the invention or of their components according to embodiments of the invention. In particular, distances and size relationships are not shown to scale in the figures. In the various figures, corresponding elements are provided with the same reference numbers.

Fig. 1 shows a fuel injection device 1, e.g. to the

Driving a motor vehicle, not shown, can be used. A high-pressure fuel pump 43, also referred to as a fuel delivery device, delivers fuel from a fuel reservoir 41 into a high-pressure chamber 9, also referred to as a fuel pressure accumulator or rail. The

High-pressure fuel pump 43 may be provided with a multi-part cylinder head 7 according to the invention. At the high-pressure chamber 9 is at least one injection element 6 is arranged. The injection element 6, the fuel directly into its associated combustion chamber 3 a

Inject internal combustion engine 5. The previously known cylinder heads for high-pressure fuel pumps are known e.g. when

Forged part made in one piece to withstand the high pressure on the cylinder head can. The production of these known cylinder heads is associated with high costs. Furthermore, the check valves previously used, which are arranged in front of the high-pressure chamber are only suboptimal functional.

2 shows an enlarged section of the high-pressure fuel pump 43 with a two-part cylinder head 7 and a modular valve plate 27. The production of the cylinder head 7 according to the invention is much simpler and cheaper than that of the known cylinder heads. Further, the check valve 31, which is integrated or embedded together with the suction valve 29 in the valve plate 27 is optimally functional.

The cylinder head 7 has a first component 11 and a second component 13. The first component 1 1 has a first cylindrical cavity 15 which is suitable for receiving and guiding a piston 17. In this case, the first cylindrical cavity 15 optionally together with the piston 17 forms a

Pump work chamber 47, in which the fuel is placed under high pressure. The fuel passes through an inlet 49, which is provided in the housing 19 of the high-pressure fuel pump 43 and in the second component 13, to a suction valve 29. From there, the fuel is the pump working space

47 supplied. The pressurized fuel then passes out of the pump working chamber 47 through the check valve 31 and a

The second component 13 is designed as a flange which is arranged outside annularly and concentrically around the first component 1 1 and allows attachment of the cylinder head 7 on the housing 19 of the high-pressure fuel pump 43 by means of screws 59. The second component 13 has a second one

cylindrical cavity 16, in which the first component 1 1 and the

Valve plate 27 are arranged. The first component 1 1 is seated with an annular shoulder 21 in the second designed as a flange member 13. The paragraph 21 is greater in a plane perpendicular to the longitudinal axis 23 of the first member 11 than the rest of the first component 11. In this case, the paragraph 21 is located on a Support surface 22 which is provided on the second component 13 for this purpose. In the illustration in FIG. 2, the individual modules of the valve plate 27 rest on the first component 1 1 following the pump working chamber 47. On the valve plate 27 follows in the second

cylindrical cavity 16 of the second component 13 of the pressure pipe socket 33, which acts as a biasing element. The pressure pipe socket 33 presses the elements located in the second cylindrical cavity 16 of the second component 13 against the first component 11 and against the housing 19.

The valve plate 27 is modular and has a first valve plate member 35 and a respective separate second valve plate member 37 and third valve plate member 39. The suction valve 29 and the check valve 31 are disposed in the first valve plate member 35. The check valve 31 is guided and has a Hubanschlagplatte 45. The suction valve 29 is guided as an outward-opening valve (A-valve) in the first valve plate member 35.

The second valve plate element 37 has a first recess 51 and a second recess 53. The first recess 51 connects the first cylindrical cavity 15 of the first component 1 1 hydraulically with the suction valve 29 and the second recess 53 connects the first

cylindrical cavity 15 of the first component 1 1 with the check valve 31st The third valve plate element 39 has a third recess 55, which connects the check valve 31 with a recess in the pressure pipe socket 33 and thus with the high-pressure chamber 9.

The valve plate members 35, 37, 39 are connected together by pins 57 and in particular thereby positioned and aligned with respect to each other. Overall, the cylinder head assembly consisting of the first component 1 1, second component 13, the valve plate 27 with the individual

Valve plate elements 35, 37, 39 and valves 27, 29, mounted on screws 59 on the housing 19 of the high-pressure fuel pump 43, so that the inlet 49 of the suction valve 29 is ensured via the inlet bore. The high-pressure fuel pump 43 according to the invention and in particular the two-part or multi-part design of the cylinder head 7 allows a simple symmetrical design of the cylinder head 7 and in particular of the first component 1 1 of the cylinder head 7. The Anflanschfunktion is taken over by a separately executed second component 13. This leads to a simplification of the manufacturing process and to considerable

Cost savings. Furthermore, the functionality of the check valve 31 is positively influenced by the integration of the check valve 31 in a valve plate 27 in the cylinder head 7.

In conclusion, it should be noted that terms such as "comprising" or the like are not intended to exclude that other elements or steps may be envisioned.Furthermore, it should be understood that "a" or "an" does not exclude a multitude

Embodiments described embodiments are arbitrarily combined with each other. It is further noted that the reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

claims

1 . Cylinder head (7) for a fuel boost pump (43) of a fuel injection device (1),

wherein the cylinder head (7) is hydraulically connected to a high-pressure chamber (9);

characterized in that

the cylinder head (7) has a valve plate (27) connected to the

High pressure chamber (9) is hydraulically connected;

wherein in the valve plate (27) in parallel a suction valve (29) and a

Check valve (31) are arranged.

2. Cylinder head (7) according to claim 1,

wherein the cylinder head (7) comprises a first component (1 1) and a second component (13);

wherein the first component (1 1) and the second component (13) are manufactured separately;

wherein the first component (1 1) has a first cylindrical cavity (15) for guiding a piston (17);

wherein the second component (13) annularly surrounds the first component (1 1); wherein the valve plate (27) on the second component (13) is arranged.

3. Cylinder head (7) according to claim 2,

wherein the first component (1 1) has an annular step (21);

wherein the shoulder (21) has a larger radial dimension in a plane perpendicular to the longitudinal axis (23) of the first component (11) than the remaining first component (11);

said second member (13) having a bearing surface (22) which in a radial dimension corresponds to the radial dimension of said shoulder (21) and is adapted to receive said shoulder (21). Cylinder head (7) according to one of claims 2 and 3,

the second component (13) having a second cylindrical cavity (16) whose longitudinal axis (23) coincides with a longitudinal axis (23) of the first cylindrical cavity (15);

wherein the valve plate (27) in its radial dimension of a radial

Dimension of the second cylindrical cavity (16) corresponds and in the second cylindrical cavity (16) is arranged.

Cylinder head (7) according to claim 4, further comprising

a pressure pipe socket (33), in its radial dimension of the radial

Dimension of the second cylindrical cavity (16) and is arranged in the second cylindrical cavity (16);

wherein the valve plate (27) between the first component (1 1) and the

Pressure pipe socket (33) is arranged.

Cylinder head (7) according to claim 5,

wherein the pressure pipe socket (33) is designed to interlock positively and / or non-positively with the second component (13);

wherein the pressure pipe socket (33) is designed to press the valve plate (27) in the direction of the first component (1 1).

Cylinder head (7) according to one of claims 2 to 6,

the valve plate (27) having a first valve plate member (35) and a separate second valve plate member (37);

wherein the suction valve (29) and the check valve (31) in the first

Valve plate element (35) are arranged;

wherein the second valve plate member (37) has a first recess (51) and a second recess (53);

wherein the first recess (51) connects the first cylindrical cavity (15) of the first component (1 1) with the suction valve (29);

wherein the second recess (53) connects the first cylindrical cavity (15) of the first component (1 1) with the check valve (31).

Cylinder head (7) according to claim 7,

the valve plate (27) further comprising a separate third valve plate member (39); wherein the third valve plate member (39) has a third recess (55) connecting the check valve (31) to the high-pressure chamber (9).

Cylinder head (7) according to claim 8,

wherein the first valve plate member (35) is connected to the second valve plate member (37) by means of at least one pin (57);

wherein the first valve plate member (35) is connected to the third valve plate member (39) by means of at least one pin (57).

High-pressure fuel pump (43) for a fuel injection device (1) having the high-pressure fuel pump (43)

a cylinder head (7) according to one of claims 1 to 9.