KR20150130301A - High pressure fuel pump comprising an outlet valve arranged between a conveyor chamber and an outlet - Google Patents

Abstract

The present invention is applicable to a high pressure pump comprising a discharge valve 32 disposed between a delivery chamber 42 and a discharge section 30 and a pressure restriction valve 54 disposed between the discharge section 30 and the delivery chamber 42. [ To a fuel pump (10). According to the present invention, the discharge valve 32 and the pressure limiting valve 54 include a common valve seat body 58.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high-pressure fuel pump having a discharge valve disposed between a delivery chamber and a discharge unit. BACKGROUND OF THE INVENTION < RTI ID = 0.0 >

The present invention relates to a high-pressure fuel pump according to the preamble of claim 1.

There is known a fuel system for an internal combustion engine that includes a high-pressure fuel pump capable of delivering a necessary amount of fuel to a fuel accumulator or a fuel distributor at a predetermined pressure. High-pressure fuel pumps generally include multiple valves. For example, such a high-pressure fuel pump is implemented as a piston insertion pump.

A problem to be solved by the present invention is that a discharge valve and a pressure limiting valve of a high-pressure fuel pump are combined and disposed in a common housing.

The above problem is solved by the high-pressure fuel pump according to claim 1. Preferred embodiments are set forth in the dependent claims. Features important to the present invention are shown in the following description and drawings, which may be important to the present invention, alone and in various combinations.

The present invention has the advantage that the discharge valve and the pressure limiting valve of the high-pressure fuel pump are combined and disposed in the common housing. In this case, since the necessary number of members is reduced, the cost can be reduced. For example, the discharge valve and the pressure limiting valve may be implemented with only six members as the case may be. In particular, the sealing sheet of the combination discharge valve and the pressure limiting valve ("valve device") according to the present invention may be disposed in a common valve seat body. Valve members or valve bodies of valve devices can be radially guided in a common housing in a simple manner.

Further, the components of the combination discharge valve and the pressure limiting valve according to the present invention can be realized by relatively simple stamping and deep drawing parts. As a result, the valve members (the "closing members") and the remaining parts of the valve arrangement can be implemented with relatively small masses. Since the valve arrangement according to the invention requires a relatively small installation space, improved flexibility in the construction of the high-pressure fuel pump can be given. Particularly a valve device with a short axial length ("installation length") can be realized.

In addition, with the valve device at least partially assembled, the limit of the maximum allowable fuel pressure for the pressure limiting valve can be adjusted "outdoors" during assembly, i.e. before final assembly of the pressure limiting valve in the fuel pump. Because of this, the addition of the value at the time of occurrence of the error is relatively small, so that the assembly error cost can be reduced. This is particularly the case when the discharge valve and the pressure limiting valve are combined and disposed in the discharge connection (which can be manufactured as a separate part) of the high-pressure fuel pump.

Further, since the valve apparatus according to the present invention has a relatively small dead space, the power output ("volume efficiency") of the high-pressure fuel pump can be increased. Assembly or final assembly of the combined discharge valve and the pressure limiting valve can be made relatively simple and inexpensive. In particular, the valve arrangement according to the present invention can be implemented without the use of a material-coupled approach.

The present invention relates to a high-pressure fuel pump comprising a discharge valve disposed between a delivery chamber and a discharge section, and a pressure-limiting valve disposed between the discharge section and the delivery chamber. According to the invention, the discharge valve and the pressure limiting valve comprise a common valve seat body. As a result, the high-pressure fuel pump according to the present invention can be manufactured relatively small, simple, and economical. Particularly, because of the common valve seat body, particularly small and simple members are required. Preferably, the valve seat body is disposed at the center between the discharge valve and the pressure limiting valve, and includes the sealing sheet necessary for the discharge valve or the pressure restricting valve, respectively, on the end surface disposed on the two end sections or opposite to each other. Hydraulic perfusion of the discharge valve may be made, for example, through a centrally located through hole, and the hydraulic perfusion of the pressure limiting valve may be effected through one or more through holes arranged in the radially outer region of the valve seat body Lt; / RTI >

When the discharge valve and the pressure restricting valve are disposed substantially coaxially with each other, a space saving arrangement is achieved, in particular. Preferably, the housing including the discharge valve and at least some members of the pressure-limiting valve and the discharge valve and the pressure-limiting valve is implemented in a substantially rotationally symmetric or radially symmetric manner. As a result, the discharge valve and the pressure limiting valve can be made very small, simple, and economical together.

The function of the pressure limiting valve can be improved if the pressure limiting valve includes a ring valve member. As a result, the pressure limiting valve can be implemented particularly efficiently and simply.

In addition, the pressure limiting valve may include a leaf spring as a valve spring. The leaf spring, for example as a sheet spring, can be manufactured relatively easily and has a small installation space. Nevertheless, a relatively large force can be generated for the pre-stress of the pressure-limiting valve.

In one embodiment of the high-pressure fuel pump, the pressure limiting valve includes a valve member formed integrally with the leaf spring. For example, leaf springs ("springs") are formed as ring springs of curved or corrugated shape. The circumferential section of the leaf spring can act as a valve body and cooperate with the valve seat in the common valve seat body. As a result, the pressure-limiting valve can be manufactured particularly simply and economically, and in particular, contains fewer individual components.

In addition, a first spring support portion for supporting a spring of the discharge valve is disposed in a housing including a discharge valve and a pressure restriction valve, a second spring support portion for supporting a spring of the pressure restriction valve is disposed in the housing, 1 and the second spring support are realized in a substantially ring shape. Preferably, the radially outer region of the first or second spring support is indented in the corresponding radially inner region of the housing. In this embodiment, the first and second spring supports are members separated from the housing, respectively, and can be implemented as a disk with a hole, in particular, for example, a ring, in particular. In addition, the first and second spring supports can each be pushed into a defined axial dimension, such that each spring force can be adjusted during assembly, for example.

In addition, the spring of the discharge valve may be a helical spring. The spiral spring can be designed to have a correspondingly greater durability with a larger spring usage than the leaf spring.

In another embodiment of the high-pressure fuel pump, the valve body of the discharge valve is embodied as a port type, and the spring of the discharge valve provides pressure to the bottom of the valve body within the radial direction of the valve body. This results in a particularly simple and reliable embodiment of the discharge valve, by which the valve body and the spring are constantly arranged at defined positions with respect to each other.

In another embodiment of the high-pressure fuel pump, the radially outer section of the valve body is radially guided within a portion of the valve seat body. This results in a coaxial arrangement of the members of the discharge valve in a particularly simple manner and provides a secure sealing fit of the valve body to the valve seat.

In an alternative embodiment of the high pressure fuel pump, the radially outer section of the valve body is radially guided in a guide member disposed separately from the valve seat body. As a result, a valve seat body having a simpler shape can be realized, and the cost can be reduced. The separately disposed guide members increase the structural possibilities in the formation of the discharge valve.

The high-pressure fuel pump according to the present invention is particularly simple when the combined discharge valve and the pressure-limiting valve are integrated into the discharge connection of the high-pressure fuel pump. As a result, the discharge valve and the pressure-limiting valve are arranged in a particularly space-saving manner. From a functional point of view, the arrangement of the discharge valve and the pressure limiting valve near the discharge of the high-pressure pump is particularly preferred. Finally, the discharge valve and the pressure relief valve must be assembled at the end of the assembly when assembling the discharge connection.

Exemplary embodiments of the present invention will now be described with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view of a high pressure fuel pump implemented in accordance with substantially prior art, for a fuel system of an internal combustion engine.
2 is an axial cross-sectional view of a discharge connection of a high pressure fuel pump according to the present invention including a combined discharge valve and a pressure limiting valve.
3 is an enlarged cross-sectional view of a combined discharge valve and pressure limiting valve similar to that of FIG. 2;
4 is a cross-sectional view of an alternative embodiment of FIG. 3 of a combined discharge valve and a pressure limiting valve.
5 is a perspective view of a valve member integrally formed with a leaf spring of a pressure limiting valve together with a part of a valve seat body;

Functionally equivalent members and sizes in all figures are denoted by the same reference numerals in different embodiments.

1 shows a schematic cross-sectional view of a high-pressure fuel pump 10 of a fuel system for an internal combustion engine (not shown). Although the high-pressure fuel pump 10 of FIG. 1 substantially corresponds to the prior art, some of the elements related to the present invention are shown at least in fig. 2 to 5 show the present invention in detail.

The high pressure fuel pump 10 includes a pump housing 12 and an electromagnet 14 including a coil 16, an armature 18 and an armature spring 20 is disposed on the left side of the pump housing . The high pressure fuel pump 10 also includes an inlet 24 connected to the low pressure line 22 and having an inlet valve 26 and a discharge outlet 24 connected to the high pressure line 28, (30). The discharge valve 32 includes a valve body 33 and a spring 35 embodied therein as a helical spring. And the discharge portion connecting portion 34 is disposed in the discharge portion 30.

Further, the high-pressure fuel pump 10 includes a pressure-limiting valve 54 indicated by a circuit symbol in the upper right region of Fig. The pressure restricting valve will be described in detail in FIGS. The pressure limiting valve 54 can be opened toward the delivery chamber 42 as opposed to the delivery direction of the high pressure fuel pump 10 determined by the discharge valve 32. [

The inlet valve 26 includes a valve spring 36 and a valve body 38. The valve body 38 is movable horizontally in the figure and can be moved by the valve needle 40 connected to the armature 18. When current is supplied to the electromagnet 14, the inlet valve 26 can be closed by the force of the valve spring 36. [ If no current is supplied to the electromagnet 14, the inlet valve 26 may be forced open by force of the armature spring 20 or may be forced to remain open.

A piston 44 is vertically movably disposed in the delivery chamber 42 as viewed in the drawing. The piston 44 can be moved in the cylinder 50 through the roller 46 by the cam 48, which is now elliptical. The cylinder 50 is formed within a portion of the pump housing 12. [ The inlet valve 26 is hydraulically connected to the outlet chamber 42 through the opening 52.

In the operating state of the high-pressure fuel pump 10, the pump feeds the fuel from the inlet portion 24 to the outlet portion 30. The discharge valve 32 is opened and closed in accordance with the hydraulic pressure difference between the delivery chamber 42 and the discharge portion 30 and according to the force of the spring 35. The inlet valve 26 is operated by the valve needle 40 or the electromagnet 14 although it is operated by the pressure difference between the inlet 24 and the outlet chamber 42 during full delivery.

The electric current is supplied to the electromagnet 14 at a specific point during the delivery stroke so that the inlet valve 26 can be closed and the fuel still present in the delivery chamber 42 can be returned to the low pressure line 22 ("Rails") (not shown) through outlet 30 without being dispensed. The volume of the high-pressure fuel pump 10 disposed within the pump housing 12 is substantially filled with fuel.

2 shows an axial cross-sectional view of the outlet connection 34 of the high-pressure fuel pump 10. The discharge valve 32 and the pressure limiting valve 54 are integrated in the discharge connection portion 34 and arranged in combination with each other. The discharge valve 32 and the pressure restriction valve 54 are disposed substantially coaxial with each other. The outlet connection 34 is also referred to hereinafter as the housing 56.

Here, the members shown in Fig. 2 are embodied as substantially rotationally symmetric or radially symmetric with respect to the longitudinal axis 55. Members that are important to the function of the combined discharge valve 32 and the pressure limiting valve 54 are disposed in the left portion of FIG. The delivery of fuel during normal operation (pressure restricting valve closure) occurs substantially from left to right in FIG.

The discharge valve 32 and the pressure limiting valve 54 include a common valve seat body 58 which is connected to the pressure limiting valve 54 (left side) and the discharge valve 32 Right side). The valve seat body 58 has a basic, substantially cylindrical shape, and is preferably disposed within the housing 56 in a pressure fit manner. Alternatively, the valve seat body 58 may be disposed in the housing 56 in a material-binding manner or in a shape-fitting manner.

A cylindrical hole 59 is disposed in the valve seat body 58 at the center in the axial direction and the hole 59 includes a portion having a diameter which is rapidly increased in the right portion as viewed in the drawing. A ported valve body 33 of the discharge valve 32 is disposed at a portion having a suddenly increased diameter and the radially outer section of the valve body 33 is connected to a portion of the valve seat body 58 having a rapidly enlarged diameter And radially guided by the radially inner wall.

The spring 35 of the discharge valve 32 formed as a helical spring inside the radial direction of the ported valve body 33 is disposed concentrically with respect to the remaining members. Since the left axial end section of the spring 35 is supported on the bottom 64 of the ported valve body 33, the spring 35 exerts pressure on the bottom 64 Provide toward the left.

The valve seat body 58 also includes a sealing sheet 66 embodied as a ring web and the bottom 64 of the ported valve body 33 relative to the sealing sheet 66 is axially urged by a spring 35 Lt; / RTI > force. 2, the right end section of the spring 35 is supported by the first spring support 68. As shown in Fig.

In the left axial end section of the valve seat body 58 as viewed in Fig. 2, the ring-shaped valve member 70 of the pressure limiting valve 54 contacts the sealing sheet 78 in the operating state shown here. The ring-shaped valve member 70 is embodied as a cylindrical disk having a hole substantially at the center. The outer diameter of the ring-shaped valve member 70 corresponds roughly to the radial inner diameter of the housing 56. There is at least a small radial gap between the ring valve member 70 and the housing 56 so that the ring valve member 70 is axially movable in the housing 56 in accordance with the function of the pressure restriction valve 54 .

2, the valve spring of the pressure limiting valve 54 is disposed on the left side of the ring-shaped valve member 70 in the form of a leaf spring 72. Wherein the leaf spring 72 is embodied as a disk having a substantially curved cylindrical shape and a hole in the center. In the drawing, a second spring support portion 74 is disposed on the left side of the leaf spring 72. Thus, the leaf spring 72 creates a pressure between the second spring supporting portion 74 and the ring-shaped valve member 70, and the valve member 70 is pressed against the sealing sheet 78 by the pressure.

In the sectional view of FIG. 2, two axial fluid channels 80 are shown in the valve seat body 58, and the fluid channels are disposed in a substantially central region in the radial direction of the valve seat body 58. In the state of the apparatus shown in Fig. 2, axial fluid channels 80 are closed by a ring-shaped valve member 70 at one side.

The spring support portions 68 and 74 are embodied in a substantially "ring-like" shape as a cylindrical disk with holes and the radially outer sections of the spring supports 68 and 74 are formed in the corresponding radial direction of the housing 56 Is placed in the inner section, where it is pressurized. The center hole enables the perfusion of the fuel.

In normal operation of the high-pressure fuel pump 10, the discharge valve 32 according to FIG. 2 operates in a manner similar to FIG. When the fuel pressure in the delivery chamber 42 in the delivery stroke of the high-pressure fuel pump 10 is larger than the fuel pressure in the high-pressure line 28 (plus the force of the spring 35) Can be separated from the sealing sheet 66 on the seat body 58 toward the right as seen in the drawing, so that the discharge valve 32 is opened.

In this case, the hydraulic connection between the delivery chamber 42 and the high-pressure line 28 and thus the delivery of the fuel is accomplished as follows: through the central opening of the second spring support 74, Through the central opening in the valve seat body 58 and then through the central opening in the valve seat body 58 and then to the outside of the ported valve body 33 Through a radial gap formed radially in the direction of the valve body 58 and into the interior of the valve seat body 58 and then into a portion of the spring 35 radially inwardly and then axially into the first spring support 68 and then into the substantially high pressure line 28 in the form of a substantially nozzle of the discharge connection 34, i.e. through a radially inner hollow chamber formed conically and cylindrically.

If the pressure in the delivery chamber 42 is less than the pressure in the high-pressure line 28 plus the force of the spring 35, the discharge valve 32 can be closed. The bottom 64 of the ported valve body 33 hits the valve seat body 58 against the ring-shaped sealing sheet 66. In this state, both the discharge valve 32 and the pressure restriction valve 54 are closed.

The fuel pressure in the high-pressure line 28 is lower than the pressure in the delivery chamber 42 and the force applied to the ring-shaped valve member 70 by the leaf spring 72, in the case of operation different from the normal operation of the high- The ring-shaped valve member 70 is separated from the sealing sheet 78, so that the pressure limiting valve 54 can be opened.

The flow of the fuel in this case is as follows: from the right side through the central inner opening of the first spring support 68, then through the spring 35 radially outwardly, Through the fluid channel 80 of the body 58 and then radially through the separate ring valve member 70 and then through the central opening in the ring valve member 70, Through the central opening in the spring 72, then through the central opening in the second spring support 74 and into the delivery chamber 42 at the end.

Briefly, if the fuel pressure in the region of the outlet 30 exceeds a predetermined maximum allowable value, then the pressure limiting valve 54 is opened, and then the pressure limiting valve 54 Lt; / RTI > Since the valve body 33 is formed in a port shape and the ring valve member 70 is disk-shaped, the two members have a relatively small mass, and therefore the discharge valve 32 and the pressure restriction valve 54 are relatively fast Open or closed.

FIG. 3 shows an embodiment of a combined discharge valve 32 and pressure limiting valve 54, similar to the embodiment according to FIG. Unlike the embodiment according to Fig. 2 in which the members are assembled from the left in the figure, in the embodiment according to Fig. 3, the members of the combination discharge valve 32 and the pressure restriction valve 54 are assembled from the right in the figure. This is made possible by the housing 56 having a diameter that is partially uniformly reduced with an axial opening in the left end section in the figure in accordance with FIG. In this case, the plate spring 72 is supported on the inner end face of the housing 56, unlike in Fig.

The housing 56 includes a radially inner diameter end in the region to the right in the figure. As a result, the members of the combination discharge valve 32 and the pressure restriction valve 54 can be assembled from the right side in the figure in the axial direction. The remaining arrangement and configuration of the members of Fig. 3 substantially correspond to those of Fig.

Fig. 4 shows another embodiment of the combined discharge valve 32 and the pressure restricting valve 54, based on Fig. Particularly, in the embodiment according to Fig. 4, the valve body 58 has a simplified shape in relation to Figs. 2 and 3. In this case, there is no radially inner-diameter jump of the center hole 59 in the valve seat body 58. [ 4, the sealing sheet 66 of the discharge valve 32, embodied as a ring web, is disposed on the right end face of the valve seat body 58, as viewed in the figure.

4, there is a guide member 76 disposed separately from the valve seat body 58 and the radially outer section of the valve body 33 includes a radially outer section of the guide member 76, Direction. Here, the guide member 76 is shown only schematically. In particular, fixing of the guide member 76 to the housing 56 is not shown for convenience.

The remaining members of the combined discharge valve 32 and the pressure limiting valve 54 correspond to those of FIGS. The function of the combined discharge valve 32 and the pressure limiting valve 54 according to Fig. 4 is also similar to that of Figs.

5 shows a perspective view of the valve member 70 formed integrally with the leaf spring 72 of the pressure limiting valve 54 together with the illustrated axial section of the valve seat body 58. In contrast to the embodiment according to FIGS. 2 to 4, the leaf spring 72 further functions as a ring-shaped valve member 70 in this case, thus "directly acting" in relation to the valve function. To this end, the leaf spring 72 comprises two sealing sections (denoted by reference numeral "70" in figure 5) embodied in a substantially cylindrical shape, The channel 80 can be closed.

In the closed state of the pressure limiting valve 54, the leaf spring 72 strikes the sealing sheet 78 of the valve seat body 58 only with a substantially cylindrical sealing section. When the fuel pressure in the high-pressure line 28 is larger than the sum of the fuel pressure in the delivery chamber 42 and the axial force provided by the leaf spring 72, the two cylindrical sealed sections of the leaf spring 72, (78), thereby enabling force flow from the high-pressure line (28) to the delivery chamber (42).

10 High-pressure fuel pump
30 outlet
32 discharge valve
33 valve body
34 outlet connection
35 spring
42 delivery chamber
54 Pressure limiting valve
58 Pressure sheet body
64 floor
68, 74 spring support
70 valve member
72 leaf spring
76 guide member

Claims (11)

A high pressure fuel including a discharge valve 32 disposed between the discharge chamber 42 and the discharge section 30 and a pressure restriction valve 54 disposed between the discharge section 30 and the discharge chamber 42, In the pump 10,
Wherein said discharge valve (32) and said pressure limiting valve (54) comprise a common valve seat body (58). The high-pressure fuel pump according to claim 1, wherein the discharge valve (32) and the pressure-limiting valve (54) are disposed substantially coaxial with each other. The high-pressure fuel pump according to claim 1 or 2, wherein the pressure-limiting valve (54) includes a ring-shaped valve member (70). The high-pressure fuel pump according to claim 3, wherein the pressure-limiting valve (54) includes a leaf spring (72) as a valve spring. The high-pressure fuel pump according to claim 1 or 2, wherein the pressure limiting valve (54) includes a valve member (70) formed integrally with the leaf spring (72). 6. A valve as claimed in any one of claims 1 to 5 wherein a spring (35) of the discharge valve (32) is supported within a housing (56) including the discharge valve (32) A second spring support portion 74 is disposed within the housing 56 to receive a spring 72 of the pressure limiting valve 54. The first and second spring support portions 68, Characterized in that the spring supports (68, 74) are implemented in a substantially ring-like configuration. The high-pressure fuel pump according to claim 6, wherein the spring (35) of the discharge valve (32) is a helical spring. 8. A valve according to any one of claims 1 to 7, characterized in that the valve body (33) of the discharge valve (32) is embodied as a port and the spring (35) of the discharge valve (32) 33) in the radial direction of the valve body (33). 9. The high-pressure fuel pump according to claim 8, wherein the radially outer section of the valve body (33) is radially guided within a portion of the valve seat body (58). 9. High pressure fuel pump according to claim 8, characterized in that the radially outer section of the valve body (33) is radially guided in a guide member (76) arranged separately from the valve seat body (58). 11. A method according to any one of claims 1 to 10, characterized in that the combined discharge valve (32) and the pressure limiting valve (54) are integrated in the discharge connection (34) of the high-pressure fuel pump (10) Fuel pump.

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