APPARATUS FOR PRESSURE CONTROL IN A FUEL FEED OF AN INTERNAL COMBUSTION ENGINE HAVING COMMON RAIL INJECTION

Abstract

The present invention relates to an apparatus (1) for pressure control in a fuel feed of an internal combustion engine with a common rail injection, comprising a housing (10) with an opening (15), and an electromagnetic high pressure valve (30), wherein the electromagnetic high pressure valve (30) is at least partially inserted into the opening (15) of the housing (10) at the end, wherein the electromagnetic high pressure valve (30) is connected in a pressure-tight manner in the opening (15) to the housing (10) by a connection (20) and the connection (20) has a first portion (21) and at least one second portion (22), and wherein the first portion (21) and the at least one second portion (22) have different mechanical and/or geometric properties.

Claims

1. Apparatus (1) for pressure control in a fuel feed of an internal combustion engine having common rail injection, comprising a housing (10) with an opening (15), and a high pressure valve (30), wherein the high pressure valve (30) is at least partially inserted on the end side into the opening (15) of the housing (10), wherein, in the inserted state, the electromagnetic high pressure valve (30) in the opening (15) is connected by a connection (20) in a pressure-tight manner to the housing (10) and the connection (20) comprises a first portion (21) and at least one second portion (22), characterized in that the first portion (21) and the at least one second portion (22) have different mechanical and/or geometrical properties.

2. Apparatus (1) according to claim 1, characterized in that the first portion (21) is formed in a manner that supports the sealing by a pressure applied to the end side of the high pressure valve (30), and that in a second portion (22) an interference fit forms a press-fit connection.

3. Apparatus (1) according to claim 1, characterized in that the housing (10) is a housing (10) of a high pressure pump or is a common rail housing (10), and in that the common rail housing (10) is in connection on the inlet side to a high pressure pump and on the output side to at least one injector.

4. Apparatus (1) according to claim 1, characterized in that the rigidity of the high pressure valve (30) in the first portion (21) is lesser than in the second portion (22), and that the pressure applied at the end side can elastically deform the high pressure valve (30) in the first area (21).

5. Apparatus (1) according to claim 1, characterized in that the rigidity of the high pressure valve (30) is lesser than the rigidity of the housing (10) in the area of the opening (15).

6. Apparatus (1) according to claim 1, characterized in that a press-fit connection between the electromagnetic high pressure valve (30) and the housing (10) is formed in the first portion (21) by an interference fit.

7. Apparatus (1) according to claim 1, characterized in that an interference fit is formed in the second portion (22), which has a smaller interference than in the first portion (21), and a press-fit connection is formed between the high pressure valve (30) and the housing (10).

8. Apparatus (1) according to claim 1, characterized in that a third portion (23) is provided, and that the third portion (23) forms a press-fit connection which has a smaller interference than the first portion (21) and/or the second portion (22), or that the third portion (23) has a transition dimension.

9. Apparatus (1) according to claim 1, characterized in that a uniform mating surface (16) is provided in the opening (15) on the housing (10).

10. Apparatus (1) according to claim 1, characterized in that the high pressure valve (30) has a valve seat body (32), and that the valve seat body (32) of the high pressure valve (30) is at least partially inserted into the opening (15) of the housing (10).

11. Apparatus (1) according to claim 10 characterized in that the valve seat body (32) has a circular annular cross-section at the end side with an inner surface (36) surrounding an inlet channel (35) and an outer surface (37a, 37b, 37c), and in that the outer surface (37b) is provided with an interference to form the second portion (22).

12. Apparatus (1) according to claim 10, characterized in that the valve seat body (32) has a preferably circumferential cavity (31) on an inner surface (36) and/or an outer surface (37a) for forming the first portion (21).

13. Apparatus (1) according to claim 10, characterized in that the third portion (23) is arranged at the end side of the valve seat body (32) and in that the second portion (22) is arranged between the third portion (23) and the first portion (21).

14. Apparatus (1) according to claim 1, characterized in that the high pressure valve (30) is a pressure control or regulating valve, in particular an electromagnetic pressure control or regulating valve.

15. Apparatus (1) according to claim 1, characterized in that the high pressure valve (30) has a pole core (40) with a front cavity (44) which cavity engages the valve seat body (32).

16. Apparatus (1) according to claim 15, characterized in that the housing (10) at least partially surrounds the pole core (40) and is fixedly connected to the pole core (40).

17. Apparatus (1) according to claim 15, characterized in that the housing (10) is welded, caulked, flanged or crimped to the pole core (40).

18. Apparatus (1) according to claim 1, characterized in that the housing (10) is made of a magnetic material and that an excitation system (50) of the electromagnetic high pressure valve (30) is arranged on the common rail housing (10).

19. Internal combustion engine with a common rail injection, comprising at least one apparatus (1) according to claim 1.

Description

[0031] Four embodiment examples of an apparatus for pressure control in a fuel feed of an internal combustion engine having common rail injection according to the invention are described here below with reference to the accompanying drawings. Wherein:

[0032] FIG. 1 shows a cross-sectional view of an apparatus for pressure control in a fuel feed of an internal combustion engine having common rail injection with a housing and a high pressure valve inserted in an opening of the housing,

[0033] FIG. 2 shows an enlarged view of a first embodiment example of the connection between the housing and the high pressure valve,

[0034] FIG. 3 shows an enlarged view of a second embodiment example of the connection between the housing and the high pressure valve,

[0035] FIG. 4 shows an enlarged view of a third embodiment example of the connection between the housing and the high pressure valve, and

[0036] FIG. 5 shows an enlarged view of a fourth embodiment example of the connection between the housing and the high pressure valve.

[0037] In the following, identical or functionally identical components are identified with the same reference signs. For the sake of clarity, not all identical or functionally identical parts are given a reference number in the individual figures. It is already noted at this point that the features of the embodiment examples described below can be combined with each other.

[0038] FIG. 1 shows a section of a common rail system of an internal combustion engine of a motor vehicle with a common rail injection. The system typically consists of a tank (not shown) for the fuel, from which fuel is supplied to a pump device (not shown) via a suitable line passing through a fuel filter (not shown). On the output side, the pump device is in connection with an input side of a generally tubular common rail housing 10. This common rail housing is, in turn, connected on the output side via suitable (not shown) feed lines and (not shown) openings to one or more (not shown) injectors

which are configured to inject the fuel into a cylinder (not shown).

[0039] The pumping device can impinge the fuel in the common rail housing 10 with a pressure of up to 3000*10.sup.5 Pa, i.e. 3000 bar, wherein the housing 10 comprises an opening 15 into which a high pressure valve 30, preferably an electromagnetic high pressure valve 30, can be inserted. The electromagnetic high pressure valve 30 can open at a predefined overpressure, whereby excess fuel can be returned from the common rail housing 10 to the tank via an outlet 19 and lines (not shown).

[0040] As can further be seen from FIG. 1, the high pressure valve 30 is inserted into the opening 15, which high pressure valve is arranged in a pressure-tight manner in the opening 15 by means of a connection 20. The high pressure valve 30 is preferably, and as shown, an electromagnetic high pressure valve 30 or an electromagnetic pressure control or pressure relief valve.

[0041] The electromagnetic high pressure valve 30 is arranged along a longitudinal axis X and comprises a valve seat body 32, pole core 40, an electromagnetic excitation system 50, an armature 42, a tappet 45 coupled to the armature 42 with a sealing ball 46 and a pot-shaped housing part 48.

[0042] The electromagnetic excitation system 50 comprises a coil 52 wound on a coil body 51, which coil is connectable to a power supply device via a plug connector 55.

[0043] The pole core 40 has a first end area, a second end area, and a through opening 41 that is coaxial to the longitudinal axis X, through which through opening the tappet 45 projects movably. The first end area faces the opening 15 of the common rail housing 10 and has a cylindrical front cavity 44 which is open to the free end of the pole core 40 and is arranged coaxially to the longitudinal axis X. The pole core 40 moreover has a plurality of channels 43 in the first end area which connect the through opening 41 to an outer circumferential surface of the pole core 40 and arranged radially with respect to the longitudinal axis X.

[0044] The valve seat body 32 is a rotationally symmetrical component, preferably made of a high-strength steel, having a first side and a second side, wherein a circumferential flange 38 may be arranged on the second side of the valve seat body 32. Furthermore, the valve seat body 32 has an inlet channel 35 which, starting from the first side of the valve seat body 32, connects the first side to the second side and, on the second side, opens into a preferably conical valve seat 33 which can be closed or released by the sealing ball 46.

[0045] A hollow shaft section 34 of the valve seat body 32 with an inner surface 36 and an outer surface 37 protrudes from the flange 38 in the direction of the first side, wherein the inner surface 36 surrounds the inlet channel 35. Correspondingly, the valve seat body 32 is annular in cross-section. The flange 38 at the second end of the valve seat body 32 is inserted into the cylindrical cavity 44 in the first end area of the pole core 40, and the pole core 40 almost completely surrounds the flange 38 of the valve seat body 32.

[0046] In the second end area, the pole core 40 is connected to the pot-shaped housing part 48 by means of a short circuit ring 47 and the pot-shaped housing part 48 is arranged around the armature 42 in such a way that the armature 42 together with the tappet 45 and the sealing ball 46 can undertake an adjustment movement along the longitudinal axis X. The short circuit ring 47 and the pot-shaped housing part 48 tightly seal the side of the pole core 40 facing away from the valve seat body 32.

[0047] The electromagnetic excitation system 50 is arranged on the pole core 40, the short circuit ring 47 and the pot-shaped housing part 48, whereby when the coil 52 is energized, the armature 42 is supplied together with the tappet 45 and the sealing ball 46, and the sealing ball 46 is pressed into the valve seat 33 of the valve seat body 32 and closes it. In the de-energized state of the coil 52, the electromagnetic high pressure valve 30 is open and fuel can flow out of the common rail housing 10.

[0048] In the opening 15 of the common rail housing 10, the electromagnetic high pressure valve 30 is connected to the common rail housing 10 by a connection 20 in the form of a non-detachable and pressure-tight press-fit connection.

[0049] During assembly of the high pressure valve 30, or alternatively of the preferred electromagnetic high pressure valve 30, the electromagnetic high pressure valve 30 is initially connected to the common rail housing 10 in the opening 15 by means of a connection 20 in the form of a non-detachable and pressure-tight press-fit connection in the opening 15. The pole core 40 is furthermore inserted into a recess, which is preferably arranged coaxially to the opening 15, up to a stop formed by a circumferential flange in the common rail housing 10 and enclosed by the same in areas.

[0050] The pole core 40 encloses a plenum in the recess with the common rail housing 10, wherein the plenum is connected to the inlet channel 35 by means of channels 43 through the pole core 40 and via the valve seat 33. The common rail housing 10 may include an outlet through which fuel discharged from the common rail housing 10 may be returned from the plenum to the tank (not shown).

[0051] In the embodiment example of FIG. 1, the pole core 40 is preferably connected to the common rail housing 10 by means of a circumferential welded connection, wherein a sealing ring 60 may be provided in a circumferential groove of the pole core 40 to ensure a seal between the pole core 40 and the common rail housing 10. However, the welded connection also allows the sealing ring 60 to be dispensed with, making the apparatus 1 suitable for use with synthetic fuels that are not compatible with conventional sealing rings.

[0052] Alternatively, the common rail housing 10 may project in a tubular shape beyond the pole core 40, wherein the electromagnetic excitation system 50 is arranged on the outer periphery of the common rail housing 10. The common rail housing 10 is part of the magnetic circuit of the electromagnetic high pressure valve 30 and, for this purpose, must, at least in this area, be made of a magnetic material. Such an arrangement enables a particularly small and compact design of the present apparatus 1 for pressure control in a fuel feed to an internal combustion engine with a common rail injection.

[0053] The pressure-tight connection 20 is realized between the outer surface 37 of the hollow shaft section of the valve seat body 32 and the opening 15 by a press-fit connection, wherein the connection 20 can be subdivided into at least two, preferably three portions 21, 22 and 23.

[0054] In the illustrated embodiment examples according to FIGS. 1-3, the opening 15 of the common rail housing 10 is a cylinder bore with a uniform mating surface, for example, with an H7 hole basis according to DIN 7154, where, in the meantime, the outer surface 37 used for forming the portions 21, 22, 23 has different geometric and/or mechanical properties, which are explained below with reference to FIG. 2 and FIG. 3.

[0055] The detailed view of the valve seat body 32 according to FIG. 2 shows that the outer surface 37 of the hollow shaft section 34 has three portions 21, 22, 23. The three portions 21, 22, 23 divide the hollow shaft section 34 into three step-shaped outer surfaces 37a, 37b, 37c, which can be connected by conical transitions.

[0056] The outer surface 37a forms the first portion 21 and is disposed adjacent the flange 38 on the hollow shaft section 34 at the second end of the valve seat body 32. The outer surface 37c forms the third portion 23 and is disposed adjacent the first end of the valve seat body 32. The outer surface 37b is disposed between the outer surface 37a and 37c and forms the second portion 22.

[0057] The portions 21, 22, 23 have different mechanical and/or geometric properties. The outer surface 37c in the third portion 23 is configured to form an interference fit with the opening 15 with an interference or clearance U1. The outer surface 37b in the second portion 22 is configured to form an interference fit with the opening 15 with an interference U2, wherein the interference U2>U1. The outer surface 37a in the first portion 21 is configured to form an interference fit with the opening 15 with an interference U3.

[0058] The first portion 21 or alternatively the outer surface 37a has a length L1 parallel to the longitudinal axis X, the second portion 22 or alternatively the outer surface 37 b has a length L2, and the third portion 23 or alternatively the outer surface 37 c has a length L3, wherein, for example, the following can apply to the lengths: L1>L2>L3. It is, in particular, preferred if the length L1>1.5*L3, preferably L1>2.5*L3.

[0059] The outer surface 37 and/or the inner surface 36 may have a chamfer at the first end, wherein the chamfer on the outside may have a chamfer angle of about 30° and the chamfer on the inner surface 36 may have a chamfer angle of about 45°.

[0060] To connect the electromagnetic high pressure valve 30 to the common rail housing 10, the valve seat body 32 is pressed into the opening 15 of the common rail housing along the longitudinal axis X, wherein the different interferences U1, U2, U3 prevent shavings from forming when the valve seat body 32 is pressed in, which could impair the tightness of the connection 20. In the first portion 21, the connection between the valve seat body 32 and the common rail housing 10 is made by means of an interference fit with a large interference U1. In the second portion, the connection between the valve seat body 32 is also an interference fit, however due to the smaller interference U2, this connection 20 is not completely pressure-tight, but rather leads to a strong drop in pressure. In the first portion, a connection between the valve seat body 32 and the common rail housing 10 can be made by a transition fit or an interference fit with a small interference U3.

[0061] The outer surface 37 according to the second embodiment example shown in FIG. 3 differs from the embodiment example shown in FIG. 2 in the configuration of the first portion 21.

[0062] The first portion 21 is configured in a manner that supports the sealing by the pressure applied to the end side of the electromagnetic high pressure valve 30. For this purpose, the first portion 21 has a cavity 31 on the outer surface 37a, which can be formed as a circumferential groove. The cavity 31 reduces a wall thickness of the hollow shaft section 34 in such a way that a fuel pressure applied at the end side in the inlet channel 35 can elastically deform the hollow shaft section 34 in the area of the cavity 31, whereby the area adjacent to the cavity 31 of the first portion 21 is pressed against the opening 15 of the common rail housing 10 in a manner that supports the sealing by pressure.

[0063] Alternatively, or in addition, the cavity 31 may also be arranged on the inner surface 36 of the hollow shaft section 34, wherein the cavity 31 on the inner surface 36 of the hollow shaft section is more complex to manufacture.

[0064] According to FIG. 4, the outer surface 37 may not be formed by step-shaped portions 21, 22, 23, but rather from at least one cone surface 37d. Together with the opening 15 of the housing 10, the cone shell surface 37d may equally form a transition or clearance fit in the third portion 23, a mild interference fit in the second portion 22, and an interference fit in the first portion 21.

[0065] The transition fit is preferably arranged on the free first side of the valve seat body 32 or alternatively on the hollow shaft section 34 and provides centering when inserted or pressed into the opening 15. A preferably continuous increase of the interference causes, on the one hand, a reduction in pressure in the axial gap between the high pressure valve 30 and the housing 10 and results in a pressure-tight connection 20 being formed between the first side and the second side by an interference fit.

[0066] In addition, a further portion can be provided with a cylindrical circumferential surface and/or a cavity 31 on the inner surface 36 and/or the outer surface 37d.

[0067] According to the fourth embodiment example shown in FIG. 5, the at least two portions 21, 22, 23 are formed by deformation in the inserted state. The outer surface 37 of the valve seat body 32 or alternatively of the hollow shaft section 34 can be a cylindrical circumferential surface before insertion into the opening 15, which is matched to the opening 15 as a clearance or the transition fit. Accordingly, the hollow shaft section 34 can be smoothly inserted in the axial direction into the opening 15 along the longitudinal axis X.

[0068] A stop 17 is provided in the opening 15, which projects radially inwards into the housing 10 in a flange shape. The mating surface 16 in the opening 15 closes off next to the stop 17, and the stop 17 can specify the position of the valve seat body 32 in the opening 15 in the longitudinal axis X.

[0069] To form the pressure-tight connection 20, the valve seat body 32 or the high pressure valve 30 is pressed into the end of the opening 15 against the stop 17 until a deformation is formed. The hollow shaft section 34 is deflected radially—preferably elastically—by the pressing force and pressed against the opening 15, whereby in this portion 22 the pressure-tight connection 20 is formed as a press-fit connection. The axial pre-tensioning of the hollow shaft section 34 in the opening 15 against the stop 17 should then be maintained. For this purpose, the pole core—as shown in FIG. 1—can be connected to the housing 10 by applying an axial force in such a way that the valve seat body 32 is held compressed in the longitudinal axis X and the pressure-tight connection 20 is permanently formed by a deflection.

[0070] The radial deflection or alternatively deformation of the hollow shaft section 34 can be facilitated by a cavity 31 on the inner surface 36 and/or outer surface 37. As previously explained, the cavity 31 can also locally reduce the rigidity of the hollow shaft section 34, which is why a pressure-assisted additional sealing effect can be exhibited.

[0071] In addition, the housing 10 and the high pressure valve 30 or alternatively its valve seat body 32, and more specifically its hollow shaft section 34, can have different rigidities, wherein the rigidity of the housing 10 is preferably greater than the rigidity of the high pressure valve 30 or alternatively its valve seat body 32. As soon as an overpressure occurs in the housing 10, the high pressure valve 30 expands to a greater extent than the housing 10, which is why the connection 20 arranged in the axial gap is kept pressure-tight with pressure assistance.

REFERENCE LIST

[0072] 1 Apparatus [0073] 10 Housing [0074] 15 Opening [0075] 16 Mating surface [0076] 17 Stop [0077] 19 Outlet [0078] 20 Connection [0079] 21 First portion [0080] 22 Second portion [0081] 23 Third portion [0082] 30 High pressure valve [0083] 31 Cavity [0084] 32 Valve seat body [0085] 33 Valve seat [0086] 34 Hollow shaft section [0087] 35 Inlet channel [0088] 36 Inner surface [0089] 37 Outer surface [0090] 38 Flange [0091] 40 Pole core [0092] 41 Through opening [0093] 42 Armature [0094] 43 Channel [0095] 44 Cavity [0096] 45 Tappet [0097] 46 Sealing ball [0098] 47 Short circuit ring [0099] 48 Housing part [0100] 50 Excitation system [0101] 51 Coil body [0102] 52 Coil [0103] 55 Plug connector [0104] 60 Sealing ring [0105] X Longitudinal axis