DE8104261U1 - LIQUID-COOLED FUEL INJECTION NOZZLE - Google Patents

Description

ROBERT BOSCH GMBH, 7000 Stuttgart 1

Liquid-cooled fuel injector

State of the art

The innovation is based on a liquid-cooled fuel Injection nozzle according to the preamble of the main claim. It is known to use one of cooling fluids in fuel injection nozzles Fluid flow-through cooling space to be provided in order to avoid overheating, which occurs in various internal combustion engines occurring high temperatures are due. So it is known from DE-OS 24 51 458, on the nozzle body by soldering, Shrink-on or roll up a cooling jacket to be attached, with at least one more elastic seal to the outside Sealing ring is arranged between the cooling jacket and the nozzle body. Fuel is used as the coolant Via a separate coolant inlet hole and a separate one Coolant return hole in the nozzle body and in the nozzle holder is fed to the cooling jacket. Such a well-known

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However, the fuel injection nozzle requires a total of three connection nipples for the inlet and the return of the coolant and for the actual fuel supply as well as one Large number of mutually separate channels in the nozzle body and in the nozzle holder, which are carefully aligned with one another must be. Such fuel injection nozzles then often have an additional leakage oil connection Leak oil return, which is via the sealing seat between the valve needle and nozzle body in the rear spring chamber got. This results in complicated and difficult to manufacture designs with enlarged external dimensions.

There is therefore a need for simplified connection options Liquid-cooled fuel injection nozzles for high demands.

Advantages of the invention

The liquid-cooled fuel injector of the invention with the characterizing features of the main claim has the advantage that a simplified arrangement the cooling and leakage oil lines results, so that the same or even smaller external dimensions can be achieved as with uncooled fuel injection nozzles of the same design, for example hole nozzles.

The measures listed in the subclaims are advantageous developments and improvements of the In the main claim specified fuel injector possible. The connection for the coolant inlet is particularly advantageous and the combined coolant return and leakage oil return via a special ring piece with a hollow

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screw. Located in the area of the nozzle body the coolant inlet and return channels in the form of circular segment-like recesses in the wall of the Cooling jacket surrounding the nozzle body.

drawing

An exemplary embodiment of the invention is shown in the drawing and is detailed in the following description explained. 1 shows a side view of a liquid-cooled Fuel injection nozzle and FIGS. 1a, 1b and 1c are partial sectional side views of essentials Sections of the fuel injector shown in FIG. 1.

Description of the exemplary embodiments

In the fuel injector shown in Fig. 1 is the The spring chamber of the nozzle holder is included in the coolant circuit, so the leakage oil return flow and the coolant return flow can be controlled summarize, and it can be dispensed with a further connection nipple leading to the outside.

In Fig. 1 one is in the usual manner from a nozzle holder

1 and a nozzle body 2 existing fuel injection nozzle, shown here in the form of a hole nozzle. The nozzle needle, not shown, is in the nozzle body

2 guided in sections in a sealing manner and arranged to be axially displaceable, with the nozzle body and valve needle also being one limit not shown pressure space, of which after

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Moving the valve needle which is supplied via a dashed channel connection 3 and an upper connection nipple 4 Fuel enters the engine's combustion chamber through injection openings.

The nozzle body 2 is via a union nut 5 below Interposition of a connecting disk 6 clamped to the nozzle holder 1, in this a space 7 for the Closing spring is present. The closing spring, not shown in the drawing, is supported on the one hand by a spring plate 8 (see Fig. 1b) on the nozzle needle and on the other hand at the bottom of the bore of the spring chamber 7.

The enlarged view of Fig. 1c of the nozzle body 2a shows at 8 that formed as an annular space Cooling space which is formed between a cooling jacket 9 fastened to the nozzle shaft 2a and the nozzle shaft. The cooling jacket can be soldered to the nozzle shaft; however, other types of fastening are also possible, for example by means of a press fit or shrink fit, also in connection with interposed sealing members. The refrigerator is over a coolant supply line 10a in the nozzle body 2 is supplied with the coolant and via a corresponding coolant return line 11a discharged again. Feed line 10a and return line 11a settle in the intermediate disk initially continued as lines 10b and 11b; however, the return line 11b for the coolant opens directly into the spring chamber 7 (see the larger detailed view of FIG. Ib), so that the returned coolant is in the Spring chamber 7 combined with the leakage oil. The continuation of returned coolant and leakage oil - it goes without saying that therefore in the usual case the coolant fuel is the same

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Chen type is how it occurs in the spring chamber 7 as leakage oil then from the spring chamber 7 via a common coolant and leakage oil return line 11c now in the nozzle holder 1. In the nozzle holder 1 there is also (see Fig. 1 with 1a) the continuation of the supply line for the coolant, which is designated here with 10c.

Figures 1 and 1a show the outward connection of the coolant inlet and the coolant and leakage oil return. The connection is in the form of a double nipple 12 formed with hollow screw 13, the hollow screw such as 1 a shows it is screwed into an internal thread on the nozzle holder 1 at 14. The hollow screw 13 has a central passage 15, which is aligned with the coolant and leakage oil return channel 11c in the nozzle holder 1. Simultaneously the banjo bolt 13 on the nozzle holder supports the double-sided sealing disks 16a, 16b in between Connection nipple 12. The double-sided connection nipple 12 comprises a central, spherical base part 12a with a central through-hole 17 for the hollow screw 13, the head of which here is in the form of an Allen screw for fastening is trained. The recirculated coolant with leakage oil then passes through an annular recess 18 on the Hollow screw 13 in the return partial channel 19 of the illustrated embodiment in the plane of the drawing on the right lying connection nipple 12b for coolant and leakage oil return.

The coolant (fuel) therefore supplied to the left connection nipple 12c is then directed downwards at an angle Inlet sub-channel 20 - the sub-channel 19 is inclined downward from the upper annular groove 18 of the hollow screw 13

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leads - to a lower annular groove 20 of the hollow screw 13 and from this via interconnection lines and recesses 22 to the above-mentioned coolant inlet channel 10c and further via 10b and 10a to the cooling space 8th.

Claims (6)

lit · ri ι * -> r t ■ · a · r π · Dlpl.-lng. Peter Otte 7033 Herrenberg (Kuppingen) Patent Attorney Eifelstrasse 7 Telephone (0 70 32) 31ΘΘΘ 1542G / ot / wi January 26, 1981 ROBERT BOSCH GMBH, 7000 Stuttgart 1 Claims for protection 1. Liquid-cooled fuel injector for internal combustion engines with a cooling jacket arranged on the nozzle body and with bores for the passage of the Coolant (fuel) in the nozzle body and nozzle holder, characterized in that on the one hand for the coolant inlet and for the combined coolant and leakage oil return, on the other hand, a double-sided connection nipple (12) attached to the nozzle holder (1) with a central banjo bolt (13) is. 2. Fuel injection nozzle according to claim 1, characterized in that that the double nipple (12) consists of two opposing connection parts (12a, 12b) and a central spherical base part (12a), which has separate channels for coolant supply and leakage oil and coolant return as well as a central bore for receiving the hollow screw shaft. 3. Fuel injection nozzle according to claim 1 or 2, characterized characterized in that a central bore (18) in the hollow screw (13) with a connecting channel (11c) from 1542G / ot / wi January 26, 1981 - 2 - Spring chamber (7) for coolant and leakage oil return in Connection. 4. Fuel injection nozzle according to one of claims 1 to 3, characterized in that the attachment the double-sided connection nipple on the nozzle holder (1) serving hollow screw (13) at least one annular groove (18, 21) in the area of the double nipple base part (12a). 5. Fuel injection nozzle according to one of Claims 1 to 4, characterized in that double nipple (12) with hollow screw (13) in an upper, an incision forming recess (25) of the nozzle holder (1) are attached. 6. Fuel injection nozzle according to one or more of the claims 1 to 5, characterized in that the channels in the opposite connection parts (12a, 12b) of the double nipple (12) in the area of the spherical base part (12a) obliquely upwards and obliquely downwards directed sub-channels (19, 20) pass over, each are in operative connection with an associated annular groove (18, 21) in the central part of the hollow screw shaft, wherein one of the annular grooves (18) is connected to the central hollow screw channel (15) via a transverse bore and the other annular groove (21) via interconnection lines (22) into a channel (10c) offset from the center in the Nozzle holder (1) opens.