Connecting piece for a fuel injector of an internal combustion engine

Abstract

The invention relates to a connecting piece for a fuel injector of an internal combustion engine comprising at least one high-pressure input port and at least one high-pressure output port, wherein the high-pressure input port and the high-pressure output port open into an internal high-pressure accumulator of the connecting piece and/or the injector via separate high-pressure feed channels.

Claims

1. A connecting piece for a fuel injector of an internal combustion engine comprising: a high-pressure input port and a high-pressure output port, an internal high-pressure accumulator extending along a longitudinal axis within the connecting piece, and the internal high-pressure accumulator having a top side, first side, and second side, a first high-pressure feed channel formed in the connecting piece, the first high-pressure feed channel opens into the first side of the internal high-pressure accumulator at a distance below the top side of the internal high-pressure accumulator and the high-pressure input port connected to the first high-pressure feed channel, a second high-pressure feed channel formed in the connecting piece, the first high-pressure feed channel opens into the second side of the internal high-pressure accumulator at a distance below the top side of the internal high-pressure accumulator and the high-pressure output port connected to the second separate high-pressure feed channel, and an internal volume of the internal high-pressure accumulator oriented along the longitudinal axis and having a greater volume than a volume of the high-pressure feed channels, the internal volume positioned between the first high-pressure feed channel and the second high-pressure feed channel such that flow along from the first high-pressure feed channel oriented on a lateral axis must enter the larger volume of the internal high-pressure accumulator oriented on the longitudinal axis before entering the second high-pressure feed channel oriented on the lateral axis.

2. The connecting piece according to claim 1, wherein the high-pressure feed channel of the high-pressure input port and/or the high-pressure feed channel of the high-pressure output port include at least one throttle.

3. The connecting piece according to claim 1, wherein the high-pressure feed channel of the high-pressure input port and the high-pressure feed channel of the high-pressure output port open directly into the internal high-pressure accumulator of the connecting piece without a throttle.

4. The connecting piece according to claim 1, wherein the connecting piece is of axially symmetrical design.

5. The connecting piece according to claim 2, wherein the high-pressure input port and/or the high-pressure output port provide a thread for the screw connection of an external high-pressure line and the threads are positioned an exterior of the connecting piece.

6. The connecting piece according to claim 1, wherein the connecting piece is designed T-shaped or as a T-piece, wherein the high-pressure ports are formed in the head area and the interface to a fuel injector housing is formed by the foot of the T-piece, wherein the internal high-pressure accumulator of the connecting piece extends in the axial direction to the interface of the T-piece, and the high-pressure feed channels open into the high-pressure accumulator at right angles to its longitudinal extension.

7. The connecting piece according to claim 1, wherein there is provided a filter housing with a filter received therein, wherein the filter housing or the filter forms the connection interface of the internal high-pressure accumulator with a fuel injector.

8. A fuel injector with at least one connecting piece according to claim 1.

9. An injection system comprising a plurality of injectors according to claim 8, which are connected in series via their connecting pieces.

10. A machine comprising an internal combustion engine and an injection system according to claim 9.

11. The connecting piece according to claim 2, wherein at least one throttle is in the form of a defined diameter taper of the respective high-pressure feed channel in the direction of the internal high-pressure accumulator.

12. The connecting piece according to claim 5, wherein the thread for the screw connection of the external high-pressure line is in the form of a thread provided on the outside of a connecting flange of the high-pressure input port or the high-pressure output port.

13. The connecting piece according to claim 1, wherein the internal high-pressure accumulator is oriented along a central axis of the fuel injector, the first high-pressure feed channel extends radially from the first side of the internal high-pressure accumulator, and the second high-pressure feed channel extends radially from the second side of the internal high-pressure accumulator.

14. The connecting piece according to claim 1, wherein the first high-pressure feed channel and the second first high-pressure feed channel are only connected through the internal volume of the internal high-pressure accumulator.

15. The connecting piece according to claim 1, wherein the internal high-pressure accumulator outputs fluid to an accumulator of a fuel injector.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further advantages and properties of the invention will be explained in detail with reference to the exemplary embodiments illustrated in the Figures, in which:

(2) FIG. 1: shows a sectional representation through the fuel injector of the invention in the area of the connecting piece according to a first embodiment,

(3) FIG. 2: shows a sectional representation of a modified fuel injector according to the invention, which is analogous to FIG. 1,

(4) FIG. 3: shows a schematic representation of the injection system according to the invention with fuel injectors as shown in FIG. 1 or FIG. 2.

DETAILED DESCRIPTION

(5) The sectional representation of FIG. 1 shows the axially symmetrical T-shaped connecting piece 10 which on its foot side is connected to the injector housing 20 by means of a screw connection. At the head area of the connecting piece 10, the ports for high-pressure lines A,B are formed on opposite sides. For example, the high-pressure line A is connected to the high-pressure input port by screwing the union nut 30 to the external thread 13A provided at the connecting flange. The high-pressure line A thereby is axially pressed into the opening of the high-pressure input port. The same is done with the high-pressure line B, which likewise is screwed to the external thread 13B provided at the high-pressure output port by means of a union nut 30. Accordingly, a series connection of injectors 20 for an injection system of an internal combustion engine can be established by means of such connecting pieces 10, without any additional connection components, such as e.g. a clamp or the like, being necessary.

(6) From each of the two high-pressure ports, an individual high-pressure feed channel 11A, 11B extends, which extends in an axial connection direction from the high-pressure input port or high-pressure output port to an internal high-pressure accumulator 15 and opens into the same. The high-pressure accumulator 15 extends transversely to the direction of the feed channels 11A, 11B, i.e. in the vertical direction up to the foot of the connecting piece 10.

(7) Both the high-pressure feed channel 11A and the high-pressure feed channel 11B each provide an integrated throttle 12A,12B which is characterized by a taper of the channel diameter of the respective high-pressure feed channel 11A, 11B in the direction of the integrated high-pressure accumulator 15. In the illustrated embodiment, both throttles 12A, 12B open directly into the integrated pressure accumulator 15, but theoretically the throttles 12A, 12B might be located in a portion of the high-pressure feed channel 11A, 11B located further centrally.

(8) Due to the fact that the high-pressure line A is merely indirectly connected to the outgoing high pressure line B via the integrated high-pressure accumulator 15, it is ensured that the pressure pulsations caused by a central high-pressure pump are eliminated or at least massively attenuated and cannot be transmitted to a connected further injector via the high-pressure channel 11B or the high-pressure line B. The integrated throttles 12A, 12B contribute to a further elimination or attenuation of the pressure waves caused by the pump.

(9) The embodiment of FIG. 2 shows a slightly modified variant of the connecting piece 10, which differs from the variant of FIG. 1 merely by the fact that the throttles 12A, 12B contained in FIG. 1 have been omitted, and the diameter of the high-pressure feed channels 11A, 11B hence remains constant along its length. In this case, only the pressure accumulator 15 ensures a sufficient elimination or attenuation of possible pressure pulsations in the high-pressure line A.

(10) In both exemplary embodiments (FIGS. 1 and 2) the fluid interface of the connecting piece 10 with the injector 20 is formed via the integrated filter 17 which is received by a filter housing 16. The filter housing 16 is inserted into the opening of the high-pressure accumulator 15 directed towards the interface. The filter housing 16 is level with the opening of the high-pressure accumulator 15, while the filter element 17 protrudes from the opening by a short piece.

(11) The high-pressure accumulator 21 of the injector shows a diameter different from the high-pressure accumulator 15 of the connecting piece 10, at least with respect to its opening diameter. Connecting piece 10 and injector 20 are connected to each other such that the two high-pressure accumulators 15, 21 and their openings are level with each other. The protruding filter element 17 of the connecting piece 10 protrudes into the high-pressure accumulator 21 of the injector.

(12) FIG. 3 shows a schematic circuitry of the injection system according to the invention with a total of four fuel injectors 20_1, 20_2, 20_3, 20_4, which each carry the connecting piece 10 according to the invention at the head-side end of the housing. The central fuel supply is designated with the reference numeral 2. The fuel is brought to the required pressure level by means of the central high-pressure pump 4, which pressure level is provided to the first injector 20_1 of the series connection via the fuel supply line 3. The supply line 3 therefor is mounted on the high-pressure input port of the connecting piece 10 of the first injector 20_1. Via the high-pressure output port of the connecting piece 10, the fuel then flows on to the subsequent injector 20_2 or the high-pressure input port of the associated connecting piece 10 present there. The output of the injector 20_2 in turn is connected to the input of the subsequent injector 20_3, from where the fuel ultimately flows to the last injector 20_4. The high-pressure output port of the fourth and hence last fuel injector 20_4 is sealingly closed by means of an appropriate sealing plug.

(13) Optionally, a further fuel outlet 5 can be provided in the area of the connecting pieces 10, via which fracture leakages can be recirculated into the fuel tank 7. A corresponding sensor 6 serves to detect possible fracture leakages. Furthermore, the fuel outlet 8 ensures the discharge of possible switching leakages from the injectors 20_1-20_4.