Water Injection Device of a Vehicle Internal Combustion Engine

Abstract

A water injection device is provided for a vehicle internal combustion engine having a storage tank for water and a conveying device which is connected to water and can convey water through a feed line into at least one injection valve which is assigned to the internal combustion engine and if required, in the case of a switched-off internal combustion engine, can convey it from the injection valve back in the direction of the storage tank. A device for separating air from the water which is conveyed back is provided in the feed line. The device for separating air is configured in the form of a container, in the upper interior region of which the at least one or more feed lines opens/open, whereas a forward feed line which is connected to the conveying device opens into the lower interior region of the container, and wherein, as viewed in the vertical direction, the upper interior region of the container is spaced apart further from a roadway, on which the vehicle is standing, than the lower interior region.

Claims

1.-4. (canceled)

5. A water injection apparatus of a vehicle internal combustion engine with a storage tank for water, comprising: a conveying apparatus which is connected to said storage tank and conveys water through a feed line into at least one injection valve which is assigned to the internal combustion engine, and conveys water back from the injection valve in a direction of the storage tank as required in case of a stopped internal combustion engine; and a separating apparatus for separating air from the water conveyed back from the injection valve in the direction of the storage tank, wherein the separating apparatus is provided in the feed line.

6. The water injection apparatus according to claim 5, wherein the separating apparatus is in the form of a vessel, in an upper interior region of which the feed line or a plurality of feed lines open, a forward feed line, which is connected to the conveying apparatus, opens in a lower interior region of the vessel, and, as viewed in a vertical direction, the upper interior region of the vessel is spaced further apart from a roadway, on which a vehicle having the water injection apparatus is standing, than the lower interior region.

7. The water injection apparatus according to claim 6, further comprising: a filter element and/or a heating element for water provided in the separating apparatus.

8. The water injection apparatus according to claim 5, further comprising: a filter element and/or a heating element for water provided in the separating apparatus.

9. The water injection apparatus according to claim 5, further comprising: a pressure sensor for determining pressure in the separating apparatus, wherein the signals of said pressure sensor are taken into consideration in a suitable manner in the case of actuating the conveying apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0010] The single FIGURE shows is a sectional outline view of an exemplary embodiment of an apparatus for the separation of air from returned water in a water injection apparatus according to the invention.

DETAILED DESCRIPTION OF THE DRAWING

[0011] The FIGURE shows merely an outline (in a section) of one exemplary embodiment of an apparatus for the separation of air from returned water in a water injection apparatus according to the invention. The FIGURE does not show a storage tank for water, a conveying apparatus for water between the storage tank and the illustrated air separating apparatus, and at least one injection valve for water, which injection valve opens into an intake section of an internal combustion engine (not shown) and is supplied by a feed line which emanates from the illustrated apparatus for the separation of air (from water which is conveyed back from the injection valve in the direction of the storage tank). The elements which are not shown here can also be gathered from the prior art which was cited at the outset.

[0012] The designation 1 denotes a vessel which acts as an apparatus 1 for the separation of air from water. The approximately circular-cylindrical vessel 1 is shown in the installed position in a motor vehicle, that is to say the cylinder axis of the vessel 1 runs in the vertical direction. Here, four connector stubs 2 for, in each case, one feed line 3 are provided on the upper end wall of the vessel 1, of which feed lines 3 only a single one is shown here. Each feed line 3 leads to a water injection valve (not shown) which opens into a constituent part of the intake section of an internal combustion engine which acts as a drive unit of the motor vehicle. What is known as a forward feed line 4 opens into the interior of the vessel 1 in its lower region, the other end of which forward feed line 4 is connected to a conveying apparatus (not shown) which, during operation of the motor vehicle, conveys or can convey water from a storage tank into the vessel 1 and through the latter to the injection valves.

[0013] As was described before the description of the figures, water is removed from the injection valves and the feed lines and is conveyed back into the storage tank at least partially in the case of the vehicle being switched off at least in the cold season, that is to say when the water which is situated, for example, in the feed lines might freeze, for which purpose, for example, the conveying apparatus can be operated with a reversed conveying direction. In order to prevent air and any particles which are contained in the air passing into the storage tank here, the apparatus 1 for the separation of air from the returned water is provided. Since the flow of water which is sucked back through the conveying apparatus is namely calmed in the volume of the vessel 1, the air collects in the vessel 1 in the upper volume region, whereas the water which has a higher specific weight passes downward to the forward feed line 4 or into the latter. The conveying apparatus is ideally operated during the returning of water into the storage tank in a manner which is suitably actuated such that a certain quantity of water which is shown here by way of a liquid level 9 always remains in the vessel 1. A suitable sensor system 5, formed by way of a pressure sensor and/or a filling level sensor which measures the height of the liquid level 9, is provided on or in the vessel 1, with the aid of the signals of which sensor system 5 an electronic control unit actuates the conveying direction in the abovementioned way.

[0014] A circular-cylindrical filter element 6 is arranged in the vessel 1 in a customary way, through which filter element 6 the water passes when flowing through the vessel 1. Furthermore, an electric heating element 7 is arranged here centrally within the filter element 6. A shut-off valve 8 is provided in the forward feed line 4, which shut-off valve 8 is closed after the return of water into the storage tank is ended.