Device for Injecting Water into a Combustion Chamber or into an Intake Tract of an Internal Combustion Engine

Abstract

A device for injecting water into a combustion chamber or into an intake tract of an internal combustion engine includes a rail and at least one injection valve connected to the rail. The connection is produced by means of a rail cup, which surrounds the injection valve at the rail-side end of the injection valve. The injection valve has a feed channel open toward the rail, in which feed channel at least some portions of an insert are received in order to reduce the feed cross-section.

Claims

1. A device for injecting water into a combustion chamber or into an intake tract of an internal combustion engine, comprising: a rail; at least one injection valve connected to the rail; and a rail cup, which surrounds the at least one injection valve at a rail-side end of the at least one injection valve and connects the at least one injection valve to the rail, wherein the at least one injection valve defines a feed channel that is open toward the rail, and at least one section of an insert is received in the feed channel so as to reduce the feed cross section.

2. The device as claimed in claim 1, wherein the insert projects into the rail.

3. The device as claimed in claim 1, wherein the insert has an outside diameter which is the same as or slightly larger than an inside diameter of the rail cup.

4. The device as claimed in claim 1, wherein the insert engages around the rail-side end of the at least one injection valve.

5. The device as claimed in claim 1, wherein the insert is produced from an elastomer material and has a radial oversize with respect to an inside diameter of the rail cup in at least one portion of the insert.

6. The device as claimed in claim 1, wherein the insert has at least one region that is produced from a material which is more hydrophilic than a material of a body in which the feed channel is formed.

7. The device as claimed in claim 1, wherein the insert extends in an axial direction over at least half a length of the injection valve.

8. The device as claimed in claim 1, wherein the insert defines at least one channel, which extends in an axial direction and is part of a feed path for the water.

9. The device as claimed in claim 1, wherein the insert forms a filter in at least one region.

10. The device as claimed in claim 2, wherein the insert includes a hollow cylindrical projection that projects into the rail.

11. The device as claimed in claim 3, wherein the insert includes a flange section that has the outside diameter.

12. The device as claimed in claim 4, wherein the insert has a collar section that engages around the rail-side end of the at least one injection valve.

13. The device as claimed in claim 5, wherein the insert has a collar section that engages around the rail-side end of the at least one injection valve, and the at least one portion of the insert having the radial oversize is in a region of the collar section.

14. The device as claimed in claim 6, wherein the at least one region of the insert is in a region of a surface facing the feed channel.

15. The device as claimed in claim 7, wherein the insert extends in the axial direction over at least two-thirds of the length of the at least one injection valve.

16. The device as claimed in claim 15, wherein the insert extends in the axial direction over at least three-quarters of the length of the at least one injection valve.

Description

[0020] Preferred embodiments of the invention are explained in greater detail below with reference to the attached drawings. In the drawings:

[0021] FIG. 1 shows a schematic longitudinal section through a device according to the invention in accordance with a first preferred embodiment,

[0022] FIG. 2 shows a schematic longitudinal section through a device according to the invention in accordance with a second preferred embodiment,

[0023] FIG. 3 shows a schematic longitudinal section through a device according to the invention in accordance with a third preferred embodiment,

[0024] FIG. 4 shows a schematic longitudinal section through a device according to the invention in accordance with a fourth preferred embodiment,

[0025] FIG. 5 shows a schematic cross section through the device of FIG. 4, and

[0026] FIG. 6 shows a view of a rail having a plurality of injection valves.

DETAILED DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 shows a first device according to the invention for injecting water into a combustion chamber or into an intake tract of an internal combustion engine. The device comprises a rail 1, which is tubular and has, in a circumferential region, at least one rail cup 3 for the connection of an injection valve 2. The rail 1 is aligned substantially horizontally, with the result that the rail cup 3 points vertically downwards. The injection valve 2 is accordingly inserted into the rail cup 3 from below during assembly.

[0028] The injection valve 2 has a valve body 15, the rail-side end of which forms a feed channel 4 open toward the rail 1. The injection valve 2 is supplied with water from the rail 1 via the feed channel 4. The feed region is sealed off from the outside by a sealing ring 13 arranged on the valve body 15. When the internal combustion engine is switched off, the injection valve 2 and the rail 1 are emptied in order to avoid icing at low outside temperatures. This is because the ice pressure arising during icing could lead to damage to the injection valve 2 and/or to the rail 1. For emptying, the water present in the injection valve 2 or in the rail 1 is sucked back into a water tank. Since a smaller volume can be emptied more quickly, the injection valve 2 illustrated has an insert 5 which reduces the flow cross section of the feed channel 4 and thus reduces the volume to be emptied, hereinafter referred to as dead volume. The insert 5 is such that it fills the volume of the rail cup 3 by means of a flange section 7, the outside diameter of which is matched to the inside diameter of the rail cup 3. The dead volume is thereby further reduced. Furthermore, the insert 5 of FIG. 1 has a hollow cylindrical projection 6, which projects into the rail 1, resulting in the formation of a threshold that prevents any residual water remaining in the rail 1 from flowing back into the injection valve 2. The inflow of water with the rail 1 filled takes place via a channel 9 of the insert 5, in the present case said channel being arranged concentrically or coaxially with the feed channel 4 of the valve body 15. The channel 9 thus forms part of a feed path 10 for the water.

[0029] FIG. 2 shows a further device according to the invention for injecting water into a combustion chamber or into an intake tract of an internal combustion engine. In contrast to the device of FIG. 1, the valve body 15 of the injection valve 2 is not surrounded by a sealing ring 13 but by a collar section 8 of the insert 5. The collar section 8 furthermore has a radial oversize with respect to the inside diameter of the rail cup 3, with the result that the insert bears against the inside of the rail cup 3 under a radial preload. The insert 5 thus replaces the sealing ring 13. Moreover, the insert 5 is guided deep into the valve body 15 of the injection valve 2, with the result that the free flow cross section is reduced over a relatively large distance. Accordingly, the dead volume in the injection valve 2 is reduced. The insert 5 shown in FIG. 2 can be produced in a particularly simple manner by overmolding. In particular, a material which, like a sealing material, has a certain elasticity can be selected as the overmolding material.

[0030] FIG. 3 shows an injection valve 2 for a device according to the invention which comprises an insert 5 that extends substantially over the entire length of the injection valve 2. This means that the insert 5 extends almost as far as an injection opening 14. The dead volume is thus reduced to a minimum. Moreover, the insert 5 shown in FIG. 3 is made of a hydrophilic material, with the result that adsorption forces cause water to rise within the injection valve 2.

[0031] FIG. 3 furthermore clearly shows that the insert 5 does not have to be of sleeve-shaped design all the way along but can have a significantly more complex geometry in order to fill the volume in the injection valve 2, apart from the required feed path 10. Water flowing in the direction of the injection opening 14 can thus flow both through and around the insert 5.

[0032] FIGS. 4 and 5 show a further injection valve 2 for a device according to the invention. In this exemplary embodiment, the insert 5 has an even more complex shape. On the rail side, the insert 5 initially forms a central channel 9. Via circumferential openings 16 in the insert 5, the feed path 10 is then directed outward, and therefore the valve body 15, together with the insert 5, delimits the feed path 10. This is followed by a section which has axially extending webs 17 arranged at equal angular intervals with respect to another (see FIG. 5). In the radial direction, the webs 17 extend up to the valve body 15, with the result that channels 9 arranged in a manner distributed over the circumference are formed as a feed path 10. The flow cross section of the channels 9 is selected to be so small that they form a filter 11, preferably a prefilter. The section with the webs 17 is followed by a section which forms a further filter 12, preferably a fine filter. For this purpose, the insert 5 has an integrated cone made of a filter fabric. The end of the cone is supported on an annular section 18 of the insert 5, said section bearing against the valve body 15 under a radial preload and thus preventing the filter 12 from being bypassed. Via the filter 12, the feed path 10 is thus directed back from the radial outside to the radial inside, wherein a centrally arranged pin-shaped section 19 of the insert 5 causes a reduction in the dead volume. The feed path 10 thus runs via an annular space 20 within the feed channel 4.

[0033] FIG. 6 shows one possible embodiment of a device according to the invention. By way of example, four injection valves 2 are connected to the rail 1. The connection is made in each case via a rail cup 3.