Water injection system for internal combustion engine and injection valve for water injection system

Abstract

A water injection system for an internal combustion engine includes at least one distributor device having at least one tubular distributor pipe and at least one disc-shaped connecting element, and at least one injection valve, wherein the injection valve has an annular electromagnetic coil acting on an armature that can move up and down, and the armature is connected to the valve element. A hollow cylindrical core is constructed on the injection valve, and the core is surrounded by the electromagnetic coil at least in sections. An inlet pipe is constructed on the injection valve, and water from the distributor device can be supplied to the injection valve via the inlet pipe. The inlet pipe of the injection valve is inserted into the cup-shaped connecting element of the distributor device and is thus connected to the distributor device. It is proposed that the distributor device includes at least one body, which extends from the distributor device into the inlet pipe of the injection valve in the interior of the cup-shaped connecting element, and the inlet pipe is penetrated by a flow channel in the axial direction, and the flow channel defines an inlet opening for supplying water from the distributor device to the injection valve.

Description

Technical Field

[0001] The present invention relates to a water injection system for an internal combustion engine. The internal combustion engine can be a gasoline engine in particular. Background Art

[0002] In order to reduce CO2 emissions, it is necessary to optimize the fuel consumption of internal combustion engines, for example by increasing the compression or by downsizing in combination with turbocharging. However, at high engine loads, internal combustion engines are generally not able to be operated at an operating point that is optimal in terms of fuel consumption, since this operation is limited by the tendency to knock and high exhaust gas temperatures. A measure for reducing the tendency to knock and for lowering the exhaust gas temperature is the injection of water, which can be injected directly into the combustion chamber of the internal combustion engine or into the intake system of the internal combustion engine.

[0003] In internal combustion engines with water injection, there is the risk that water-conducting lines and / or components will freeze at low temperatures and be damaged by the ice pressure. To prevent this, the water-conducting lines and / or components are usually drained when the engine is stopped.

[0004] DE 10 2015 208 472 A1 discloses, for example, an internal combustion engine with a water injection device, which includes a water tank for storing water, a pump for conveying water, and a water injection valve for injecting water. The pump is connected to the water tank via a first line on the inlet side and to the water injection valve via a second line on the outlet side. In order to simply empty the pump, the pump is arranged above the water tank so that it can be emptied by gravity. Alternatively or additionally, the pump can be operated in the opposite conveying direction.

[0005] In order to prevent the injection valves of such injection systems from freezing, the injection valves must also be emptied. From the publication DE 10 2015 208 508 A1, a water injection device for an internal combustion engine is known, which includes at least two injection valves or water injectors, which are emptied successively by reversing the conveying direction of the conveying unit. Therefore, the injection valves or water injectors do not have to be designed to withstand ice pressure. By emptying the injection valves in sequence, the existing water should be reliably removed. The air sucked in through the open injection valves should be additionally emptied when emptying. Summary of the invention

[0006] The object of the present invention is to provide an injection valve for a water injection system of an internal combustion engine which can be emptied particularly easily and / or quickly during the back suction operation of the water injection system in order to prevent the injection valve from freezing and thus damage to the injection valve.

[0007] In order to achieve this object, a water injection system according to the invention is proposed. Advantageous embodiments of the invention are also described below.

[0008] According to the present invention, a water injection system for an internal combustion engine is proposed. The water injection system includes at least one distributor device, which has at least one tubular distributor pipe and at least one cup-shaped connecting element. In addition, the injection system includes at least one injection valve, wherein the injection valve has an annular electromagnetic coil for acting on an armature that can be lifted and lowered, and the armature is connected to the valve element, wherein a hollow cylindrical core is constructed on the injection valve, and the core is at least partially surrounded by the electromagnetic coil, wherein an inlet pipe is constructed on the injection valve, and water from the distributor device can be supplied to the injection valve via the inlet pipe. In the water injection system, the inlet pipe of the injection valve is inserted into the cup-shaped connecting element of the distributor device and is thus connected to the distributor device. According to the present invention, the distributor device includes at least one body, which extends from the distributor device into the inlet pipe of the injection valve in the interior of the cup-shaped connecting element. Here, the body is penetrated by a through-flow channel in the axial direction, and the through-flow channel defines an inlet opening for supplying water from the distributor device to the injection valve. Here, the distributor pipe, the cup-shaped connecting element and the body form a unit as a distributor device. In this case, the distributor tube, the cup-shaped connecting element and the main body are firmly connected to one another and form a continuous component.

[0009] If the injection valve is inserted into the cup-shaped connecting element during assembly of the water injection system, the body enters into the inlet connection piece of the injection valve. The inlet opening of the injection valve is therefore not formed by the inlet connection piece, but by the body inserted into the inlet connection piece. The body thus reduces the free flow cross section available for the water supply to the injection valve. At the same time, the dead volume present in the inlet connection piece, which must be evacuated in order to prevent the injection valve from freezing, is minimized. This means that less water must be sucked back from the injection valve.

[0010] The injection valve is therefore supplied with water exclusively via a through-flow channel formed in the body. The through-flow channel extends in the axial direction, preferably coaxially with the longitudinal axis of the injection valve.

[0011] Furthermore, the reduced free flow cross section of the flow channel formed in the body also increases the flow velocity during the suction back of water, so that at the same time the emptying of the injection valve is accelerated. In addition, the reduced flow cross section counteracts eddies. As a result, with the same suction back power of the conveyor unit used for the suction back, significantly more water is sucked back from the injection valve in the same time. This means that at low outside temperatures the risk of ice formation and damage to the injection valve due to ice pressure is significantly reduced.

[0012] The through-flow channel formed in the body preferably has a cylindrical shape. In addition, the diameter of the through-flow channel is preferably selected to be as small as possible in order to achieve the highest possible flow speed during the back suction and to produce an uninterrupted water column. At the same time, the diameter is dimensioned in such a way that a sufficient water supply to the injection valve is also guaranteed. Preferably, the diameter of the through-flow channel is selected to be smaller than the diameter of the distributor device. The diameter of the through-flow channel can be, for example, 2 to 4 mm. The body forming the through-flow channel preferably has a minimum wall thickness, which corresponds to the radius of the through-flow channel or is greater than the radius of the through-flow channel.

[0013] A distributor device for supplying water to at least one injection valve is also referred to as a rail. Typically, the rail has at least one cup-shaped connecting element for connecting an injection valve. This connecting element is also referred to as a rail cup. Here, the rail cup surrounds the end of the injection valve on the inlet side. Therefore, the dead volume of the rail cup depends on the specific configuration of the rail cup and the configuration of the inlet-side end of the injection valve. In the water injection system according to the present invention, the body is constructed on the distributor device so that when the injection valve is inserted into the cup-shaped connecting element, the body extends into the inlet pipe of the injection valve. Therefore, with the aid of the distributor device, any injection valve, such as a fuel injection valve, can be made into an injection valve for water injection according to the present invention.

[0014] Due to the reduced dead volume in the injection valve and possibly in the cup-shaped connecting element, the connecting element can be emptied more easily and more quickly during back suction, so that the risk of ice formation and thus damage caused by ice pressure is significantly reduced. The robustness of the water injection system is also increased accordingly.

[0015] According to an advantageous embodiment, the body is directly connected to the distributor pipe, in particular welded, and protrudes from the distributor pipe. Thus, a simple and cost-effective structure of the distributor device can be achieved, and the injection valve can be easily mounted on the distributor device.

[0016] According to an advantageous embodiment, it is provided that the cup-shaped connecting element is directly connected to the body, in particular welded to the body. Thus, a simple and cost-effective structure of the distributor device can be achieved, and the injection valve can be easily mounted on the distributor device.

[0017] According to an advantageous embodiment, the body protrudes from the distributor pipe and extends through the cup-shaped connecting element. In this case, the body can additionally serve to reduce the dead volume that is usually retained in the cup-shaped connecting element of the distributor device, which is used to connect the injection valve to the distributor device. Thus, the amount of water sucked back when the system is emptied can be further reduced.

[0018] According to an advantageous embodiment, the cup-shaped connecting element and the body extending into the injection valve are designed in one piece. This allows a simple and cost-effective design of the distributor device and allows the injection valve to be easily mounted on the distributor device. The body and the cup-shaped connecting element do not have to be subsequently connected to one another, for example welded, but can advantageously be made in one piece.

[0019] According to an advantageous embodiment, the body extending into the inlet connection piece has a collar, wherein the body contacts the distributor pipe at the collar and / or the cup-shaped connecting element rests on the collar. Thus, the body can advantageously be well and reliably fixed to the distributor pipe by means of the collar, for example welded to the distributor pipe at the collar. The distributor device can advantageously be well sealed by means of the supporting surface of the body formed by the collar on the distributor pipe and the body can be stably fixed to the distributor pipe.

[0020] According to an advantageous embodiment, the body extending into the inlet connection piece has a further ring, wherein the cup-shaped connecting element rests on the further ring. Thus, the cup-shaped connecting element can be advantageously well and reliably fixed to the body via the further ring, for example welded to the body on the ring. The distributor device can advantageously be well sealed by the bearing surface of the body formed by the further ring on the cup-shaped connecting element, and the cup-shaped connecting element can be stably fixed to the body.

[0021] According to an advantageous embodiment, it is provided that the cup-shaped connecting element at least partially surrounds the inlet connector of the injection valve and the body inserted into the inlet connector.

[0022] According to an advantageous embodiment, it is provided that the body projects into the inlet connection piece of the injection valve in a tubular manner and that the volume available to the water in the inlet connection piece is thus reduced by the body.

[0023] Preferably, the proposed water injection system further comprises a water tank for storing water and a conveying unit for conveying water. The conveying unit is preferably capable of reversing the conveying direction, so that the conveying unit can also be used to suck water back from the injection valve. The conveying unit can be, for example, a motor-driven pump, the conveying direction of which can be reversed in order to be able to suck water back into the water tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. The accompanying drawings show:

[0025] Figure 1 Schematic longitudinal section of an injection system according to the invention according to a first preferred embodiment,

[0026] Figure 2Schematic longitudinal section of an injection system according to the invention according to a second preferred embodiment,

[0027] Figure 3 Schematic longitudinal section of an injection system according to the invention according to a third preferred embodiment,

[0028] Figure 4 Schematic longitudinal section of an injection system according to the invention according to a fourth preferred embodiment,

[0029] Figure 5 Schematic longitudinal section of an injection system according to the invention according to a fifth preferred embodiment,

[0030] Figure 6 Schematic longitudinal section of an injection system according to the invention according to a sixth preferred embodiment,

[0031] Figure 7 Schematic longitudinal section of an injection system according to the invention according to a seventh preferred embodiment,

[0032] Figure 8 Schematic longitudinal section of an injection system according to the invention according to an eighth preferred embodiment,

[0033] Fig. 9 Schematic longitudinal section of an injection system according to the invention according to a ninth preferred embodiment,

[0034] Fig.10 A schematic diagram of a water injection system according to the present invention, and

[0035] Fig.11 In the intake system of an internal combustion engine Fig.10 Schematic diagram of the injection valve of a water injection system. DETAILED DESCRIPTION

[0036] Depend on Figures 1 to 9 A water injection system for an internal combustion engine can be seen. The water injection systems shown in the figures each comprise at least one injection valve 1 and a distributor device 7. The distributor device 7 is also referred to as a rail and is used to distribute water to the various injection valves 1. Thus, water can be distributed via the distributor device 7 to a plurality of injection valves 1, for example to four injection valves 1.

[0037] The injection valve 1 comprises an annular electromagnetic coil 2 for acting on an armature 3 that can be lifted and lowered and is connected to a valve element 4. The valve element 4 is designed as a hollow needle and is connected to a spherical valve closing element 29 at its end facing away from the armature 3 for releasing and closing at least one injection opening 30. When the electromagnetic coil 2 is energized, a magnetic field is formed, the magnetic force of which moves the armature 3 together with the valve element 4 and the valve closing element 29 in the direction of the core 5, so as to close the working air gap 31 formed between the core 5 and the armature 3. Here, the spherical valve closing element 29 releases the injection opening 30. If the energization of the electromagnetic coil 2 is subsequently terminated, the armature 3, the valve element 4 and the valve closing element 29 are reset to their initial positions by means of the spring force of the return spring 32, so that the valve closing element 29 closes the injection opening 30 again. The core 5 is designed as a hollow cylinder and is connected to the inlet pipe 6 via a hollow cylindrical connecting element 33, via which the injection valve 1 can be supplied with water from a distributor device 7.

[0038] Furthermore, the water jetting device comprises a distributor device 7. The distributor device 7 is also referred to as a rail. The distributor device 7 comprises a distributor pipe 40, at least one cup-shaped connecting element 12 and a body 8.

[0039] The injection valve 1 of the water injection device is connected to the distributor device 7 via a cup-shaped connecting element 12, also referred to as an injector cup. This connection can be, for example, a plug connection, a compression connection, a clamping connection, a latching connection and / or a threaded connection. In this way, the connection of the injection valve 1 to the distributor device 7 can be simplified.

[0040] The cup-shaped connecting element 12 at least partially surrounds the inlet connection piece 6 of the injection valve 1 and / or the body 8 inserted into the inlet connection piece 6. Here, the axial and / or radial gap remaining between the cup-shaped connecting element 12 and the inlet connection piece 6 or the body 8 can be used to receive a sealing element 13, in particular a sealing ring 13, so that the inlet area of ​​the injection valve 1 is sealed to the outside.

[0041] The cup-shaped connecting element 12 has a shoulder 27 , so that the cup-shaped connecting element 12 transitions into the distributor device 7 via a section with a reduced inner diameter.

[0042] Furthermore, the distributor device 7 comprises a body 8 which projects in the axial direction into the inlet connection piece 6 of the injection valve 1 and thus reduces the volume in the inlet connection piece 6 which is available to the water.

[0043] In order to reduce the dead volume in the inlet region of the injection valve 1, a body 8 projects into the inlet connection piece 6 of the injection valve 1 and is penetrated by a through-channel 9 which defines an inlet opening 10. The injection valve 1 is therefore supplied with water from the distributor device 7 only via the through-channel 9. The outer contour of the body 8 is adapted, for example, to the inner contour of the inlet connection piece 6, so that only a small gap or no gap remains between the body 8 and the inlet connection piece 6. Furthermore, the outer contour of the body 8 can be adapted to the inner contour of the inlet connection piece 6, so that the body 8 reduces the dead volume in the inlet region of the injection valve 1. This is not shown in the figures.

[0044] The measures proposed for reducing the dead volume contribute to the fact that injection valve 1 and cup-shaped connecting element 12 can be emptied quickly by back suction, so that there is no need to fear damage due to frozen water when the internal combustion engine is stopped and the outside temperature is low.

[0045] exist Figures 2 to 9 Various exemplary embodiments of water injection systems are shown in FIG.

[0046] The body 8 can be connected directly to the distributor pipe 40, in particular welded thereto, for example, and thus protrude from the distributor pipe 40. Figures 1 to 7 is shown in the embodiment of the present invention.

[0047] The cup-shaped connecting element 12 for receiving the injection valve 1 is directly connected to the body 8 and can be welded to it. Figures 1 to 7 In the embodiment shown in Figures 1 to 4 and Figures 6 to 9 In the embodiment of the present invention, the body 8 extends through the central opening of the cup-shaped connecting element 12 and at the same time protrudes from the distributor pipe 40. The central opening of the cup-shaped connecting element 12 can have a flange, for example. On this flange, the body 8 can contact the cup-shaped connecting element 12 and be welded to the connecting element. The flange can be as in Figure 1 and 3 In the embodiment shown in FIG. 1 , it is directed in the direction of the injection valve 1 or in the embodiment shown in FIG. Figure 2 , 4 , pointing in the direction of the distributor pipe 40 as shown in the embodiments of 6-9.

[0048] exist Figure 5 In the embodiment shown, the body 8 is not directly connected to the distributor pipe 40. In this embodiment, the body 8 is constructed in one piece with the cup-shaped connecting element 12.

[0049] Rings 11a, 11b may be formed on the body 8. Figures 1 to 7 In the embodiment of FIG. 8 , the ring 11 a is formed on the body 8 , on which the body 8 rests on the distributor pipe 40 and is welded to the distributor pipe 40 on the ring 11 a. Figure 6In the embodiment of FIG. 1 , the cup-shaped connecting element 12 rests against the ring 11 a from opposite sides at the same time.

[0050] exist Figures 3 to 5 In the embodiment of the present invention, in addition to the ring 11a, another ring 11b is also configured on the body 8. In these embodiments, the cup-shaped connecting element 12 is abutted against the other ring 11b.

[0051] exist Figure 8 and 9 , in which the distributor pipe 40 is constructed as a hose, the body 8 is connected to the distributor pipe 40 constructed as a hose, and the cup-shaped connecting element 12 is arranged on the body 8 and connected to the body. The injection valve 1 is inserted into the cup-shaped connecting element 12. Figure 8 and 9 In the embodiment of FIG. 4 , the distributor pipe 40 configured as a hose, the body 8 and the cup-shaped connecting element 12 also together constitute a distributor device.

[0052] Depend on Fig.10 A water injection system with at least one injection valve 1 can be seen. The system shown includes, for example, four such injection valves 1. The injection valves 1 are connected to a distributor device 7 or a rail to which water is supplied from a water tank 15. Water is supplied to the distributor device 7 via a water line 17 by means of a conveying unit 16. The conveying unit 16 is currently implemented as a pump that is arranged outside the water tank 15 and can be driven by an electric motor. However, other embodiments of the conveying unit 16 are also possible. The conveying unit 16 can be arranged in particular in the water tank 15 or integrated into the tank bottom. The conveying unit 16 should be designed in such a way that a reversal of the conveying direction can be achieved so that ice pressure-sensitive pipes and / or components of the system, in particular the injection valves 1, can be emptied by back suction.

[0053] In order to prevent water from flowing back from the water tank 15 in the direction of the conveyor assembly 16 after emptying, a shut-off element 18, in particular a shut-off valve, can be arranged in the water line 17 upstream of the conveyor assembly 16. In the present case, a filter 19 is arranged upstream of the shut-off element 18, which is intended to prevent harmful particles from entering the conveyor assembly 16 and the injection valve 1.

[0054] exist Fig.10In the system shown, a return line 22 branches off from the water line 17 downstream of the delivery unit 16 and ends in the water tank 15. The excess delivery volume of the delivery unit 16 can be led back to the water tank 15 via the return line 22, for example, in order to regulate the pressure in the distributor device 7. For regulating the pressure, a pressure sensor 23 can be provided in the distributor device 7 or in the water line 17. In order not to draw water from the water tank 15 via the return line 22 during the back-sucking process, a non-return valve 20 is provided in the return line 22. In addition, a throttle valve 21 is arranged upstream of the non-return valve 20, by means of which a blocking pressure can be built up for pressure regulation.

[0055] As from Fig.11 It can be seen that the injection valve 1 is arranged on an intake pipe 24, via which combustion air is supplied to a combustion chamber 25 of the internal combustion engine. The water injection thus takes place outside the combustion chamber 25. Water is supplied to the combustion chamber 25 together with the combustion air. The fuel is injected directly into the combustion chamber 25 by means of a fuel injector 26.

[0056] As in Figure 5 and 6 As shown in , the body 8 can also protrude into the distributor pipe 40. Thus, a reservoir can be formed in the distributor pipe 40 around the body 8, in which water remaining in the distributor pipe 40 can collect when the distributor pipe 40 is emptied. Thus, the body 8 protruding into the distributor pipe 40 ensures that water remaining in the distributor pipe 40 cannot flow into the injection valve 1.

[0057] Of course, other embodiments and combinations of the illustrated embodiments are possible.

Claims

1. A water injection system for an internal combustion engine, the water injection system comprising: at least one distributor device (7) having at least one tubular distributor pipe (40) and at least one cup-shaped connecting element (12), - at least one injection valve (1), wherein the injection valve (1) has an annular electromagnetic coil (2) for acting on an armature (3) that can be lifted and lowered, the armature being connected to a valve element (4), wherein a hollow cylindrical core (5) is formed on the injection valve (1), the core being at least partially surrounded by the electromagnetic coil (2), wherein an inlet connector (6) is formed on the injection valve (1), via which water from a distributor device (7) can be supplied to the injection valve (1), wherein the inlet connector (6) of the injection valve (1) is inserted into a cup-shaped connecting element (12) of the distributor device (7) and is thus connected to the distributor device (7), It is characterized in that the distributor device (7) comprises at least one body (8), which extends from the distributor device (7) into the inlet pipe (6) of the injection valve (1) in the interior of the cup-shaped connecting element (12), and is penetrated by a flow channel (9) in the axial direction, which defines an inlet opening (10) for supplying water from the distributor device (7) to the injection valve (1).

2. The water injection system according to claim 1, characterized in that: The body (8) is directly connected to the distributor pipe (40) and protrudes from the distributor pipe (40).

3. The water injection system according to claim 1 or 2, characterized in that: The cup-shaped connecting element (12) is directly connected to the body (8).

4. The water injection system according to claim 1 or 2, characterized in that: The body (8) protrudes from the distributor tube (40) and extends through the cup-shaped connecting element (12).

5. The water injection system according to claim 1 or 2, characterized in that The cup-shaped connecting element (12) and a body (8) projecting into the injection valve (1) are formed in one piece.

6. The water injection system according to claim 1 or 2, characterized in that: The body (8) extending into the inlet connection piece (6) has a collar (11a), wherein the body (8) is in contact with the distributor pipe (40) on the collar (11a) and / or the cup-shaped connecting element (12) rests on the collar (11a).

7. The water injection system according to claim 1 or 2, characterized in that: The body (8) which projects into the inlet connector (6) has a further collar (11b), wherein the cup-shaped connecting element (12) rests against the further collar (11b).

8. The water injection system according to claim 1 or 2, characterized in that: The cup-shaped connecting element (12) surrounds an inlet connector (6) of the injection valve (1) and a body (8) inserted into the inlet connector (6) at least in sections.

9. The water injection system according to claim 1 or 2, characterized in that: The body (8) projects into the inlet connection piece (6) of the injection valve (1) in a tubular manner and the volume available to the water in the inlet connection piece (6) is therefore reduced by the body (8).

10. The water injection system according to claim 1 or 2, characterized in that: The water injection system also includes a water tank (15) for storing water and a conveying unit (16) for conveying water.

11. The water injection system according to claim 1, characterized in that: The body (8) is directly welded to the distributor pipe (40).

12. The water injection system according to claim 3, characterized in that: The cup-shaped connecting element (12) is directly welded to the body (8).

13. The water injection system according to claim 10, characterized in that The conveying direction of the conveying unit (16) can be reversed in order to enable the water to be sucked back into the water tank (15).

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