Injector for a fuel supply system of an internal combustion engine and fuel supply system

Abstract

An injector for a fuel supply system of an internal combustion engine, namely for a common rail fuel supply system of an internal combustion engine which is formed in particular as a large diesel internal combustion engine or ship's diesel internal combustion engine, having an injection nozzle, a control valve and a retaining body. The injection nozzle and the control valve form a clamped composite, and the composite formed of the injection nozzle and control valve can be mounted on the retaining body as a unit and disassembled from the retaining body as a unit.

Claims

1. An injector for a fuel supply system of an internal combustion engine, comprising: an injection nozzle having an external thread; a control valve; at least one radially extending intermediate plate configured as one of a valve plate and a throttle plate and axially positioned between the injection nozzle and the control valve, wherein the at least one intermediate plate is clamped between the injection nozzle and the control valve; a clamping sleeve configured to seal and cover parting surfaces between one the control valve, the intermediate plate, and the injection nozzle, and having at least one radially inward directed projection; and wherein the clamping sleeve, the injection nozzle, the intermediate plate, and the control valve form a clamped assembly, and wherein the clamped assembly formed of the injection nozzle and the control valve is configured to be mounted and unmounted as a unit, wherein the control valve has at a radially outer lateral surface: a radially inwardly directed recess configured as a circumferential groove, wherein the clamping sleeve has the at least one radially inwardly directed projection configured as a circumferential bead at a first portion that cooperates with the at least one of the radially inwardly directed recess of the control valve to fix the clamping sleeve in a position on the control valve, wherein the clamping sleeve has an internal thread at a second portion that mates with the external thread of the injection nozzle.

2. The injector according to claim 1, wherein the clamping sleeve is configured to cover the at least one intermediate plate.

3. The injector according to claim 2, wherein the radially inward directed projections of the clamping sleeve are spaced axially from one another, and wherein, after a deformation of the clamping sleeve that surrounds at least portions of the injection nozzle and the control valve during assembly of the injector, the radially inward directed projections engage by positive engagement in the radially inward directed projections while providing the clamped assembly.

4. The injector according to claim 1, wherein the clamped assembly is configured to be clamped when the injection nozzle and the clamping sleeve are screwed together, and wherein the clamping sleeve is configured to cover respective parting surfaces between one or more of the control valve, the injection nozzle, and the at least one intermediate plate.

5. The injector according to claim 1, further comprising: bore holes that extend in longitudinal direction defined in each of the control valve and the injection nozzle; and clamping screws configured to extend into respective bore holes.

6. The injector according to claim 5, wherein the bore holes are threaded bore holes with internal thread at least in the injection nozzle that are configured to mate with external threads of the clamping screws, and wherein the bore holes have a shoulder configured to mate with a flange of the clamping screws so that the clamped assembly is clamped by tightening the clamping screws.

7. The injector according to claim 6, wherein the bore holes are incorporated in the at least one intermediate plate.

8. The injector of claim 1, wherein the fuel supply system is a common rail fuel supply system and the internal combustion engine is one of a large diesel internal combustion engine and a ship's diesel internal combustion engine.

9. The injector of claim 1, wherein the clamping sleeve has an internal thread at a second portion that only mates with the external thread of the injection nozzle.

10. The injector according to claim 1, wherein the at least one radially inward directed projection is arranged between axial ends of the clamping sleeve.

11. The injector according to claim 1, wherein at least one of the radially inwardly directed recess or the at least one shoulder of the control valve is arranged between axial ends of the control valve.

12. The injector according to claim 1, wherein the at least one radially extending intermediate plate, the injection nozzle, and the control valve have a substantially same radial dimension.

13. A fuel supply system, namely common rail fuel supply system of an internal combustion engine which is formed in particular as a large diesel internal combustion engine or ship's diesel internal combustion engine, comprising: a low-pressure region; a pump arrangement having at least one high-pressure pump to convey fuel from the low-pressure region of the fuel supply system into a high-pressure region; a pressure accumulator system having at least one storage unit that is permanently under high pressure is arranged in the high-pressure region between the pump arrangement and injectors associated with cylinders; at least one first high-pressure fuel line that is permanently under high pressure that couples the pressure accumulator system to the pump arrangement; at least one injector comprising: an injection nozzle; a control valve; at least one radially extending intermediate plate axially positioned between the injection nozzle and the control valve, wherein the at least one intermediate plate is configured as one of a valve plate and a throttle plate and clamped between the injection nozzle and the control valve; and a clamping sleeve configured to seal and cover parting surfaces between the control valve, intermediate plate, and the injection nozzle, and having radially inward directed projections, wherein the clamping sleeve, the injection nozzle, injection nozzle, intermediate plate, and the control valve form a clamped assembly, and wherein the clamped assembly formed of the injection nozzle and the control valve is configured to be mounted and unmounted as a unit; wherein the control valve has at a radially outer lateral surface: a radially inwardly directed recess configured as a circumferential groove, wherein the clamping sleeve has the at least one radially inwardly directed projection configured as a circumferential bead at a first portion that cooperates with the at least one of the radially inwardly directed recess of the control valve to fix the clamping sleeve in a position on the control valve, wherein the clamping sleeve has an internal thread at a second portion that mates with the external thread of the injection nozzle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred further developments of the invention are indicated in the subclaims and the following description. Embodiment examples of the invention are described more fully with reference to the drawings without the invention being limited to these embodiment examples. The drawings show:

(2) FIG. 1 is a highly schematic cross section through a portion of an injector of a common rail fuel supply system;

(3) FIG. 2 is a highly schematic exploded view of the injector of FIG. 1;

(4) FIG. 3 is a highly schematic cross section through a portion of an injector of a common rail fuel supply system;

(5) FIG. 4 is a highly schematic exploded view of the injector of FIG. 3;

(6) FIG. 5 is a modification of FIG. 3;

(7) FIG. 6 is a further modification of FIG. 3;

(8) FIG. 7 is a highly schematic cross section through a portion of an injector of a common rail fuel supply system; and

(9) FIG. 8 is a highly schematic exploded view of the injector of FIG. 7.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(10) The present invention is directed to a common rail fuel supply system of a large diesel internal combustion engine, particularly of a ship's diesel internal combustion engine operating on heavy oil. Common rail fuel supply systems of this kind have a low-pressure region and a high-pressure region.

(11) The high-pressure region of a common rail fuel supply system comprises a pump arrangement 102 having at least one high-pressure pump and a pressure accumulator system 101 having at least one storage unit. The pump arrangement delivers fuel from the low-pressure region to the high-pressure region and is connected to the pressure accumulator system by at least one high-pressure fuel line 105. The pressure accumulator system and the high-pressure fuel line, or each high-pressure fuel line, connecting the pressure accumulator system to the pump arrangement are permanently under high working pressure.

(12) Starting from the pressure accumulator system, the fuel can be injected into cylinders by injectors, each injector being connected to the pressure accumulator system by at least one high-pressure fuel line 104, which is also permanently under high working pressure.

(13) FIGS. 1 and 2 show details of a first injector 1 of a common rail fuel supply system. The components of the injector 1 shown in FIGS. 1 and 2 are the injection nozzle 2, a control valve 3 and intermediate plates 4 and 5, i.e., a valve plate 4 and a throttle plate 5, which are positioned between the injection nozzle 2 and the control valve 3. Also, the injector 1 has a retaining body 100, shown in FIG. 2, which is engaged by the control valve 3. This retaining body preferably provides a storage for fuel that is individualized for the injector.

(14) The injection nozzle 2 and the control valve 3 have a plurality of delicate components. In order to facilitate mounting of the injection nozzle 1 and control valve 3 on the retaining body of the respective injector 1 and, therefore, on the internal combustion engine, it is suggested according to one embodiment of the invention that the injection nozzle 2 and control valve 3 are formed or provided as a clamped composite 6, so that the composite 6 formed of the injection nozzle 2 and control valve 3 can be mounted on the retaining body as a unit and disassembled from the retaining body as a unit in a simple manner.

(15) In the embodiment shown in FIGS. 1 and 2, in which the valve plate 4 and throttle plate 5 are positioned between the control valve 3 and the injection nozzle 2, these intermediate plates 4 and 5 are also clamped together with the injection nozzle 2 and control valve 3 to form the composite 6, so that this unit can be mounted on the retaining body, not shown, of the injector 1 and disassembled therefrom in a simple manner.

(16) In the embodiment shown in FIGS. 1 and 2, the control valve 3, the injection nozzle 2 and the intermediate plates 4 and 5 positioned therebetween in the embodiment shown in FIGS. 1 and 2 are clamped of a clamping sleeve 7. A radially inwardly directed recess 8 is formed at an outer lateral surface of the injection nozzle 2, and a radially inwardly directed recess 9 is formed at an outer lateral surface of the control valve 3, and radially inwardly directed projections 10 and 11 of the clamping sleeve 7 respectively engage in these recesses 8 and 9. In the embodiment shown in FIGS. 1 and 2, the recesses 8 and 9 are formed at the outer lateral surfaces of the injection nozzle 2 and control valve 3 as circumferential grooves, and the projections 10 and 11 of the clamping sleeve 7 are formed as circumferential beads that engage in these grooves. The clamping sleeve 7 is a relatively thin-walled clamping sleeve 7 and, after being fitted over the injection nozzle 2 and control valve 3, can be deformed such that its projections 10 and 11 engage in the recesses 8 and 9 of injection nozzle 2 and control valve 3 by positive engagement while clamping the composite 6. The deformation of the clamping sleeve 7 is preferably effected through plastic deformation thereof. It can be seen from FIG. 1 that in the clamped state of the composite 6 the clamping sleeve 7 covers parting surfaces between the clamped components, i.e., a parting surface between the control valve 3 and the valve plate 4, a parting surface between the valve plate 4 and the throttle plate 5, and a parting surface between the throttle plate 5 and the injection nozzle 2. In this way, a sealing function is provided by the clamping sleeve 7 with respect to these parting surfaces.

(17) FIGS. 3 and 4 show a second embodiment of an injector 1 in the region of an injection nozzle 2, a control valve 3 and the intermediate plates 4 and 5, namely the valve plate 4 and throttle plate 5, positioned between the injection nozzle 2 and control valve 3. In the embodiment shown in FIGS. 3 and 4, these assemblies are also clamped together as composite 6 by a clamping sleeve 7. Accordingly, the clamping sleeve 7 serves to clamp the control valve 3, injection nozzle 2 and the two intermediate plates 4 and 5. In the clamped state of the composite 6, the clamping sleeve 7 again covers parting surfaces between the clamped elements 2, 3, 4 and 5. However, the specific construction or configuration of the clamping sleeve 7 in the embodiment example in FIGS. 3 and 4 differs from the embodiment example in FIGS. 1 and 2.

(18) In the embodiment in FIGS. 3 and 4, a shoulder 12 is formed at the radially outer lateral surface of the control valve 3 and cooperates with a radially inwardly directed projection 13 of the clamping sleeve 7 such the clamping sleeve 7 is fixed in position at the control valve 3. At an oppositely located portion, the clamping sleeve 7 has an internal thread 14 which cooperates with an external thread 15 of the injection nozzle 2, specifically in such a way that elements 2, 3, 4 and 5 are clamped as composite 6 when the injection nozzle 2 and clamping sleeve 7 are screwed together by their threads 14 and 15.

(19) FIGS. 5 and 6 show injectors 1 and 1, which are modifications of the injector 1 from the embodiment in FIGS. 3 and 4. Therefore, to prevent unnecessary repetition, the same reference numerals are used for the same assemblies and only the details distinguishing the embodiment of FIGS. 5 and 6 from the embodiment of FIGS. 3 and 4 will be addressed in the following.

(20) The embodiment in FIG. 6 differs from the embodiment in FIGS. 3 and 4 only in that the shoulder 12 of the control valve 3 which, together with the projection 13 of the clamping sleeve 7, provides for fixing the position between the clamping sleeve 7 and control valve 3 is formed at a middle portion of the control valve 3 for geometric shortening of the clamping sleeve 7.

(21) The embodiment of FIG. 5 differs from the embodiment in FIGS. 3 and 4 in that a circumferential groove 9 is formed at the outer lateral surface of the control valve 3 corresponding to the embodiment of FIGS. 1 and 2, and a circumferential projection 11 of the clamping sleeve 7 engages by positive engagement in the circumferential groove 9 to fix the clamping sleeve 7 in position at the control valve 3.

(22) A further embodiment of an injector 1 according to the invention is shown in FIGS. 7 and 8. FIGS. 7 and 8 again show the injection nozzle 2. the control valve 3 and the intermediate plates 4 and 5 of the injector 1 which are clamped according to the invention to form the composite 6 which can then in turn be mounted on or disassembled from the retaining body, not shown, as a unit in a simple manner.

(23) In the embodiment in FIGS. 7 and 8, clamping screws 16 are used to clamp the composite 6 comprising the elements or components mentioned above. The clamping screws 16 extend into corresponding bore holes 17, which are incorporated in the above-mentioned components, i.e., in the injection nozzle 2, the control valve 3 and the intermediate plates 4 and 5.

(24) The bore holes 17 incorporated in the injection nozzle 2 are threaded holes having an internal thread 22, which cooperate with corresponding external threads 18 of the clamping screws 16.

(25) The bore holes 17 incorporated in the control valve 3 and intermediate plates 4 and 5 are constructed as threadless through-holes. Shoulders 19 are formed in the region of the through-holes 17 of the control valve 3, and a flange 20 of the respective clamping screw 16 contacts the shoulders 19 so that when the clamping screws 16 are tightened a corresponding clamping force is applied via the control valve 3 to the composite 6 comprising control valve 3, injection nozzle 2 and the existing intermediate plates 4 and 5.

(26) Cylindrical pin-like cylindrical surfaces provide thickened portions 21 of the clamping screws 16 in order to align and fix the clamping screws 16 in position in the bore holes 17 so as to ensure a defined clamping of the composite 16.

(27) In the illustrated embodiments of the injectors 1, 1, 1, 1, 1, two intermediate plates, namely the valve plate 4, 4, 4 and the throttle plate 5, 5, 5, are positioned between the respective injection nozzle 2, 2, 2 and the respective control valve 3, 3, 3. It is also possible to provide only one of these intermediate plates 4, 4, 4 or 5, 5, 5 or no intermediate plates.

(28) Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.