Water injection system for an internal combustion engine and motor vehicle with such a water injection system

Abstract

Water injection system (1) for an internal combustion engine (2) of a motor vehicle, with a water tank (3) for storing water; Water injectors (5) for injecting water into air and / or fuel that can be supplied to the internal combustion engine (2); a water pipe (4) which connects the water tank (3) to the water injectors (5); a purely mechanical ventilation valve (14; 14a, 14b; 14c), which is provided on the water pipe (4), prevents water from flowing out of the water pipe (4) and allows air to flow into the water pipe (4), wherein the water pipe (4) is designed at its end connected to the water injectors (5) as a water distributor (6) from which the water injectors (5) branch off, wherein the vent valve (14; 14a, 14b; 14c) is provided on the water distributor (6).

Description

[0001] The invention relates to a water injection system for an internal combustion engine in which water is injected into an air channel through which air can be supplied to the internal combustion engine.

[0002] Water injection systems, in which water is added to the air or fuel system of an internal combustion engine and mixes with it, are becoming increasingly important in the automotive industry. The advantages of such water injection include, in particular, increased performance, reduced exhaust emissions, and lower fuel consumption. One problem associated with water injection systems is that lines and components must be kept as free of water as possible after the engine is switched off, as otherwise, at sub-zero temperatures, there is a risk of the water freezing and damaging the lines or components. Water injection systems are known from the prior art. For example, DE 10 2014 204 509 A1 discloses a water injection system for an internal combustion engine.Furthermore, DE 10 2015 208 508 A1 also discloses an example of a water injection device for an internal combustion engine.

[0003] It is therefore an object of the present invention to prevent damage to the water injection system caused by freezing water. This object is achieved by a water injection system according to claim 1 and a motor vehicle according to claim 9. Advantageous embodiments of the invention are the subject of the dependent claims.

[0004] According to one embodiment of the invention, a water injection system for an internal combustion engine of a motor vehicle is provided, comprising a water tank for storing water; water injectors for injecting the water into air supplied to the internal combustion engine and / or into fuel supplied to the internal combustion engine; a water line connecting the water tank to the water injectors; and a purely mechanical vent valve provided on the water line, which prevents water from flowing out of the water line and allows air to flow into the water line. This vent valve provides a simple and cost-effective way to vent the water line and the water injectors after the internal combustion engine is switched off, thus preventing damage from ice pressure.

[0005] According to a further embodiment of the invention, the vent valve, viewed along the water pipe, is arranged closer to the water injectors than to the water tank. This allows for more effective venting at the essential points.

[0006] According to a further embodiment of the invention, the ventilation valve is arranged in the area of ​​the water injectors.

[0007] According to the invention, the water pipe at its end connected to the water injectors is designed as a water distributor from which the water injectors branch off, with the air vent being provided on the water distributor. This allows the air vent to be attached to the water distributor in a relatively simple manner.

[0008] According to a further embodiment of the invention, an air filter is provided on an air side of the ventilation valve.

[0009] According to a further embodiment of the invention, the water injection system further comprises a water tank pump which is adapted to pump water from the water tank to the water injectors, wherein the water tank pump is additionally adapted to draw water from the water line into the water tank in the reverse direction.

[0010] According to a further embodiment of the invention, the ventilation valve is designed as a check valve with a spring-loaded closing element.

[0011] According to a further embodiment of the invention, the ventilation valve has at least one rubber lip.

[0012] According to a further embodiment of the invention, the water injection system further comprises an air duct through which air can be supplied to the combustion engine, wherein the water injectors are adapted for injecting the water into the air duct.

[0013] Furthermore, the present invention provides a motor vehicle with such a water injection system.

[0014] A preferred embodiment of the present invention is described below with reference to the accompanying drawings. These drawings illustrate the following: Fig. Figure 1 schematically shows a water injection system according to an embodiment of the present invention, and Fig. 2a schematically shows a ventilation valve according to an embodiment of the present invention; Fig. Figure 2b schematically shows a ventilation valve according to a further embodiment of the present invention, and Fig. Figure 2c schematically shows a ventilation valve according to a further embodiment of the present invention.

[0015] Fig. Figure 1 schematically shows a water injection system 1 according to an embodiment of the present invention. This water injection system 1 is associated with an internal combustion engine 2, which is preferably a gasoline engine, but could also be a diesel engine. The internal combustion engine 2 is, for example, installed in a motor vehicle, preferably a land vehicle, such as a passenger car or a motorcycle.

[0016] The water injection system 1 comprises a water tank 3 from which a water line 4 leads to water injectors 5. One end of the water line 4, on the water injector side, is designed as a water distributor 6, from which the water injectors 5 branch off. More precisely, the water distributor 6 is formed by a pipe component to which the water injectors 5 are directly attached or to which pipe sections are attached that lead directly to the water injectors 5. The water injectors 5 are configured to inject water, preferably distilled water, stored in the water tank 3 into an air duct 7. In the air duct 7, the injected water is mixed with the air supplied to a combustion chamber 8 of the internal combustion engine 2. Furthermore, fuel is supplied to the combustion chamber 8 via a fuel system in a known manner. The fuel system comprises a high-pressure pump 9, a fuel distributor 10, and fuel injectors 11.The high-pressure pump 9 compresses a fuel to, for example, a pressure of more than 100 bar, in particular more than 200 bar, at a fuel distributor side of the high-pressure pump 9, so that the compressed fuel is forced into the fuel distributor 10 and stored there for injection into the combustion chamber 8 of the internal combustion engine 2. From the fuel distributor 10, the fuel is injected into the combustion chamber 8 of the internal combustion engine 2 in a known manner by means of the fuel injectors 11. In addition to the injection of water by the water injectors 5 into the air duct 7, or alternatively, it is possible for the water injectors 5 to inject the water into the fuel system. Preferably, in this case, the water injectors 5 would inject the water into the fuel upstream of the high-pressure pump 9.

[0017] A water tank pump 12 is arranged in (or on) the water tank 3, which pumps the water stored in the water tank 3 via the water line 4 to the injectors 5. A water filter 13 is provided in the water line 4 for filtering the water, through which the water pumped in the water line 4 flows. According to the invention, a vent valve 14 is provided in the area of ​​the water injectors 5, with which ambient air can be selectively drawn into the water line 4 and the water distributor 6. The vent valve 14 is a purely mechanical vent valve, i.e., it is not electrically controllable. Furthermore, the vent valve 14 is arranged closer to the water injectors 5 than to the water tank 3 when viewed along the water line 4. Preferably, the vent valve is attached directly to the water distributor 6.The ventilation valve 14 is designed to always prevent water from flowing from the water side of the ventilation valve 14 to the air side. Furthermore, the ventilation valve 14 is designed to allow ambient air to pass from the air side to the water side of the ventilation valve 14 when a negative pressure on the water side is sufficient to overcome the closing force of the ventilation valve 14. An air filter 15 is provided on the air side of the ventilation valve 14 to ensure that only filtered ambient air reaches the water side of the ventilation valve 14. As explained above, the water line 4, the water injectors 5, and the water distributor 6 should be kept as free of water as possible after the combustion engine 2 has been switched off.For example, the water tank pump 12 is adapted so that it can also be operated in such a way that the water from the water line 4 is drawn back into the water tank 3. If the water injection system 1 is to be vented after the combustion engine is switched off, the water tank pump 12 is operated in such a way that it draws the water located in the water line 4 and the fuel distributor 6 back into the water tank 3. This opens the vent valve 14, so that ambient air is drawn into the fuel distributor 6 and the water line 4. To also vent the water injectors 5, they can be briefly opened while the water tank pump 12 is drawing water from the water line 4, so that air is drawn from the air duct 7 into the injectors 5 and the water is pumped from the injectors 5 into the fuel distributor 6, from where it can be drawn back into the fuel tank 3 via the water line 4.

[0018] The Fig. Figures 2a to 2c show various embodiments of the ventilation valve 14, wherein the embodiments are in the Fig. 2a and Fig. 2b refers to check valves with a spring-loaded closing element.

[0019] Fig. Figure 2a shows a ventilation valve 14a with a disc-shaped closing element 16, which, in the closed state of the ventilation valve 14a, rests on a valve seat 17. On the side of the closing element 16 opposite the valve seat 17, the ventilation valve 14a is biased by a spring 18, which pushes the closing element 16 towards the valve seat 17. Furthermore, in Fig. Figure 2a shows one end of the water distributor 6, which is designed as a pipe component. The ventilation valve 14a and the ventilation valves described below are shown. Fig. 2b and Fig. 2c can be inserted into one end of the water distributor 6 so that they close this end of the pipe component.

[0020] Fig. Figure 2b shows a ventilation valve 14b in which a spherical closing element 19 rests on a valve seat 20 when the ventilation valve 14b is closed. A spring 21 is provided on the side of the closing element 19 opposite the valve seat 20, which pushes or biases the closing element 19 towards the valve seat 20.

[0021] Fig.Figure 2c shows a ventilation valve 14c, which has one or more rubber lips 18. The rubber lips 18 are arranged obliquely in a passage of the ventilation valve 14c such that a free end of the rubber lip(s) 18 is located closer to the water side of the ventilation valve 14c than a fixed end, where the rubber lip(s) 18 is connected to a wall of the ventilation valve 14c. In a closed state of the ventilation valve 14c, the free ends of the rubber lips 18 are in contact with each other, or, in the case of only one rubber lip 18, it is in contact with the wall of the ventilation valve 14c.

[0022] While the invention has been illustrated and described in detail in the drawings and the preceding description, this illustration and description is to be understood as illustrative or exemplary and not as limiting, and it is not intended to limit the invention to the disclosed embodiment. The mere fact that certain features are mentioned in various dependent claims is not intended to imply that a combination of these features could not also be advantageously used.

Claims

[1] Water injection system (1) for an internal combustion engine (2) of a motor vehicle, with a water tank (3) for storing water; Water injectors (5) for injecting the water into an air that can be supplied to the internal combustion engine (2) and / or into a fuel that can be supplied to the internal combustion engine (2); a water pipe (4) connecting the water tank (3) to the water injectors (5); a purely mechanical ventilation valve (14; 14a, 14b; 14c) which is provided on the water pipe (4), blocks the outflow of water from the water pipe (4) and allows the inflow of air into the water pipe (4), wherein the water line (4) is designed at its end connected to the water injectors (5) as a water distributor (6) from which the water injectors (5) branch off, wherein the ventilation valve (14; 14a, 14b; 14c) is provided on the water distributor (6). [2] Water injection system (1) according to claim 1, wherein the vent valve (14; 14a, 14b; 14c) is arranged closer to the water injectors (5) than to the water tank (3), viewed along the water line (4). [3] Water injection system (1) according to one of the preceding claims, wherein an air filter (15) is provided on an air side of the ventilation valve (14; 14a, 14b; 14c). [4] Water injection system (1) according to one of the preceding claims, further comprising a water tank pump (12) adapted to convey water from the water tank (3) to the water injectors (5), wherein the water tank pump (12) is additionally adapted to suck water from the water line (4) into the water tank (3) in the opposite direction. [5] Water injection system (1) according to one of the preceding claims, wherein the venting valve (14; 14a, 14b) is designed as a check valve with a spring-loaded closing element (16; 19). [6] Water injection system (1) according to one of claims 1 to 5, wherein the venting valve (14; 14c) has at least one rubber lip (18). [7] Water injection system (1) according to one of the preceding claims, further comprising an air duct (7) via which air can be supplied to the internal combustion engine (2), wherein the water injectors (5) are adapted to inject the water into the air duct (7). [8] Motor vehicle with a water injection system (1) according to one of claims 1 to 7.

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