Rail for supplying water into combustion chambers of an internal combustion engine

Abstract

A rail (1) for supplying water into combustion chambers of an internal combustion engine, said rail comprising at least one water-conducting component (2) made of plastic.

Description

[0001] Rail for supplying water to the combustion chambers of an internal combustion engine

[0002] The addition of water to the combustion chambers of an internal combustion engine is becoming increasingly important. This is done primarily to cool the combustion chambers, thereby improving the engine's efficiency. However, water can also be added to the combustion chambers to ensure cleaner combustion.

[0003] Especially in high-performance engines, water is preferably added individually to each combustion chamber. Rail systems can be used for this purpose, in which the water is supplied in a line running along a series of combustion chambers, with injection valves located along each line to allow for individual water metering to each combustion chamber in the row. Such rail systems are also common for supplying fuel to the combustion chambers of internal combustion engines.

[0004] The addition of water to combustion chambers typically occurs alongside the addition of fuel. A water injection rail system is therefore an additional system on an internal combustion engine. For this reason, weight is particularly critical for such a system. Furthermore, different requirements apply to this type of system than to a fuel injection rail system. One relevant issue is freeze resistance. Water can freeze, and a water injection rail system should ideally be designed to withstand freezing without damage. Moreover, the requirements for keeping the cost of an additional fuel injection rail system low are typically very high. Pressures used to add water to combustion chambers are generally lower than the pressures used to supply fuel.Starting from this, the object of the present invention is to at least partially solve the problems described with reference to the prior art and in particular to propose a rail for adding water to combustion chambers of an internal combustion engine, which is lightweight, can be manufactured cost-effectively and has high freeze resistance.

[0005] These problems are solved with a rail according to the features of the independent claim. Further advantageous embodiments are specified in the dependent claims, as well as in the description and, in particular, in the description of the figures. It should be noted that a person skilled in the art can combine individual features in a technologically meaningful way and thereby arrive at further embodiments of the invention.

[0006] This document describes a rail for supplying water to the combustion chambers of an internal combustion engine, which includes at least one water-carrying component made of plastic.

[0007] The rail is made primarily of a high-performance plastic that exhibits very high strength. Preferably, the rail consists at least partially of PEK, PEEK, or PPS.

[0008] Combustion chambers of an internal combustion engine are primarily cylinders. The fuel rail is specifically designed to be arranged along a bank of cylinders or combustion chambers of an internal combustion engine to supply water to each cylinder or combustion chamber as needed. In an internal combustion engine with multiple cylinder banks (e.g., a V-engine or a boxer engine), several such rails can be used (preferably one for each cylinder bank). The use of plastic for such a rail is highly unusual. Fuel rails for supplying combustion chambers of an internal combustion engine with fuel are typically made of metal, particularly because fuel is usually supplied to the combustion chambers of an internal combustion engine at very high pressures, and metallic materials are especially well-suited to withstand such high pressures.For this reason, it would initially have seemed obvious to design rails for the (additional) supply of water to the combustion chambers of an internal combustion engine from metal. Surprisingly, however, it turned out that the requirements for supplying water to the combustion chambers of an internal combustion engine are linked to other requirements that can be very well met with a rail made of a plastic material, or in particular with a rail made of a high-performance plastic.

[0009] Particularly preferred is the rail having a plastic rail line which can be arranged along a series of cylinders and at which branch positions are arranged where injection valves can be connected for metered delivery of water to the combustion chambers of the internal combustion engine.

[0010] The rail line primarily serves as a reservoir in which pressurized water is provided, which is then supplied to the combustion chambers of the internal combustion engine as needed via the injection valves located at the branch positions.

[0011] It is preferred if the rail is manufactured using an injection molding process.

[0012] Plastic components can be manufactured very efficiently (even with highly complex geometries) using injection molding. By using plastic for the rail, plastic injection molding processes can be applied to its production. Using plastic injection molding allows for the implementation of particularly advantageous rail geometries, shapes, and designs with minimal effort. Producing comparable geometries from metal materials is significantly more complex.

[0013] Especially if a heating element is integrated into at least one water-bearing component made of plastic.

[0014] It is further advantageous if the heating element is at least partially made of an electrically conductive plastic.

[0015] It is preferred if the rail is designed for the direct addition of water into the combustion chambers of the internal combustion engine.

[0016] It is also preferred if the rail is designed to add water to intake lines for drawing air into the combustion chambers of the internal combustion engine.

[0017] The closer a fuel rail is positioned to the combustion chambers of the internal combustion engine, the higher the temperatures that can occur in its immediate vicinity. In particular, the high-performance plastics described above are capable of withstanding very high temperatures, allowing the described fuel rail to be used very close to the combustion chambers (e.g., in the immediate vicinity of a cylinder head). Specifically, it is also possible to use the fuel rail for direct water injection into the combustion chambers of the internal combustion engine. In this process, the water is injected directly into the combustion chambers of the internal combustion engine (independent of the intake air). If necessary, the fuel rail can be shielded from the internal combustion engine with additional heat shielding, which can also be made of metal, for example.For example, a shielding plate can be positioned between the plastic fuel rail and the internal combustion engine. However, it is also possible to supply water by injecting it into the intake manifold of the engine. For instance, the injection can occur into the intake manifold after it branches to individual combustion chambers. In this case, individual water supply to each combustion chamber is also possible. The water then enters the combustion chamber of the engine through the intake manifold and intake valves, along with the intake air.

[0018] The described rail is suitable for both applications - both for the direct injection of water and for the injection of water into the intake manifold of the internal combustion engine.

[0019] It is also preferred if the rail is formed with a first rail component which is closed by a lid-like second rail component.

[0020] The first rail component preferably forms a water-bearing cavity of the rail, which is closed by the second rail component.

[0021] It is also advantageous if a heating element is integrated into the second rail component.

[0022] It is also preferred if the second rail component is an essentially flat cover.

[0023] The first rail component preferably has a complex geometry, particularly forming the rail line and the branch points on the rail line where the injection valves are located. In contrast, the second rail component is very simple and serves to close off the first rail component to form the rail. This division of the rail structure into a complex first rail component and a (relatively) simple second rail component reduces the manufacturing effort for producing the rail, as the effort is concentrated in the first rail component.

[0024] Furthermore, it is preferred if the first rail component is manufactured without undercuts, at least in some sections.

[0025] By dividing the rail into the first rail component and the second rail component, it becomes possible to manufacture the first rail component at least partially without undercuts - especially in an injection molding process.

[0026] The term "at least partially undercut-free" here means that undercuts are avoided in at least certain areas of the first rail component. The production of undercuts using conventional injection molding processes is, in principle, possible through appropriately designed geometries and segmented injection molds with cores. In the production of the first rail component using an injection molding process, a core is preferably used, for example, to form a feed line to which a supply line for the rail can be connected.

[0027] It is particularly preferred if the first rail component forms at least a section of a U-shaped profile, which forms the rail line and which is closed by the lid-like second rail component.

[0028] It is also preferred if the first rail component and the second rail component are welded together using a plastic welding process.

[0029] Furthermore, it is preferred if the wall thickness of the first rail component is greater than that of the second rail component. This ensures that, in the event of water freezing in the rail or its cavity, a defined deformation of the second rail component occurs, while the shape of the first rail component remains essentially unchanged. This guarantees a defined and reproducible deformation behavior of the rail during freezing, which also ensures that the rail and connected components (e.g., injectors) are not damaged by freezing. Any ice pressure resulting from freezing can be compensated for by the deformation of the second rail component within the rail.

[0030] In other embodiments, the first rail component and the second rail component can also be bonded together. However, it is particularly preferred if the rail components are welded together, because this creates a particularly strong bond.

[0031] Furthermore, it is preferred if connection structures at branch positions for connecting injection valves are formed from plastic and are integrally molded onto a first rail component of the rail on one underside. Optionally, contact surfaces for sealant (e.g., O-rings) are arranged in the connection structures, with which the injection valves and the rail are fluid-tightly sealed against each other, so that water passing from the rail into the injection valves does not leak.

[0032] The underside is preferably arranged opposite the formed cavity on the U-shaped profile formed by the first rail component.

[0033] The connection structures at the branch positions preferably comprise geometries to which the injection valves can be connected. These connection structures can be, for example, screw connections or bayonet fittings, to which corresponding injection valve geometries can be attached. A particular advantage is that such connection structures can be very efficiently molded onto the first rail component using injection molding processes for manufacturing the first rail component.

[0034] It is further preferred that a heating element is integrated into the first rail component and / or the second rail component. Such a heating element can, in particular, be made at least partially of an electrically conductive plastic. The heating element is especially preferably integrated into the second rail component. As described above, the second rail component is preferably shaped much less complexly than the first rail component. This makes it possible to integrate a heating element into the second rail component particularly efficiently. In embodiments, it is possible, for example, to manufacture the second rail component (almost) entirely from an electrically conductive plastic, which can be used to generate heat. The second rail component, which is made of an electrically conductive plastic, can (e.g.,metallic) conductor structures may be integrated, which can be used to apply current to the electrically conductive plastic in order to heat it.

[0035] The invention and its technical context are explained in more detail below with reference to the figures. The figures show a preferred embodiment, to which the invention is not limited. It should be noted that the figures and the size relationships depicted in the figures are only schematic. The following are shown by way of example and schematically:

[0036] Fig. 1: a described rail in a three-dimensional view;

[0037] Fig. 2: a first cross-section through a described rail;

[0038] Fig. 3: another cross-section through a described rail; Fig. 4: a described rail with a heating element in a three-dimensional view;

[0039] Fig. 5: a first cross-section through a described rail according to Fig. 4;

[0040] Fig. 6: a further cross-section through a described rail according to Fig. 4; and

[0041] Fig. 7 shows a rail component designed as a heating element for a described rail.

[0042] Fig. 1 shows a described rail 1 in a three-dimensional view. The rail line 2, formed by the first rail component 5 and the second rail component 6, is visible. Injection valves 4 are arranged at branch positions 3 of the rail 1, through which the water supplied via the rail 1 can be made available to the combustion chambers of an internal combustion engine (not shown here). The rail 1 has a supply line 9 (preferably integrally formed on the first rail component 5) through which the water can be supplied to the rail 1.

[0043] Figure 2 shows a schematic longitudinal cross-section through the rail 1 according to Figure 1. The water-carrying cavity 7, formed by the first rail component 5 and closed by the lid-like second rail component 6, is visible. The supply line 9 is also shown schematically. At the branch positions 3, connection structures 8, shown schematically here, are formed to which the injection valves 4 can be connected. These connection structures 8 can be, for example, screw connections or bayonet fittings. It is also shown that the first rail component 5 and the second rail component 6 are connected to each other by a connection 10. A welded connection is particularly preferred, forming a material-bonded connection between the first rail component 5 and the second rail component 6.

[0044] According to Fig. 3, the cross-section AA already shown in Fig. 2 is represented by the rail 1. It can be seen that the first rail component 5 is U-shaped.

[0045] forms a profile which is closed by the lid-like second rail component 6.

[0046] Figures 4 to 6 essentially correspond to Figures 1 to 3. Here, the rail 1 has a heating element 11, which may preferably be integrated into a second rail component 6 of the rail.

[0047] Fig. 7 shows in detail a second rail component 6 for a rail, which may be made (optionally entirely) of an electrically conductive plastic 12. Conductor structures 13 (preferably metallic) are integrated into the electrically conductive plastic 12, through which an electric current can be introduced into the electrically conductive plastic 12. The electric current is converted into heat in the electrically conductive plastic.

[0048] Reference symbol list

[0049] 1 Rail

[0050] 2 Rail line 3 Branch position

[0051] 4 injectors

[0052] 5 First Rail Component

[0053] 6 Second Rail Component

[0054] 7 Water-bearing cavity 8 Connection structure

[0055] 9 Supply line

[0056] 10 connection

[0057] 11 Heating element

[0058] 12 Electrically conductive plastic 13 Conductor structures

Claims

Claims 1. Rail (1) for supplying water to combustion chambers of an internal combustion engine, comprising at least one water-carrying component (2) made of plastic.

2. Rail (1) according to claim 1, comprising a rail line (2) made of plastic, which can be arranged along a series of cylinders and at which branch positions (3) are arranged, at which injection valves (4) can be connected for metered delivery of water to the combustion chambers of the internal combustion engine.

3. Rail (1) according to one of the preceding claims, wherein the rail is manufactured by an injection molding process.

4. Rail (1) according to one of the preceding claims, wherein a heating element (11) is integrated into the at least one water-carrying component (2) made of plastic.

5. Rail (1) according to claim 4, wherein the heating element (11) is at least partially formed from an electrically conductive plastic.

6. Rail (1) according to any one of claims 1 to 5, wherein the rail (1) is configured for the direct addition of water into combustion chambers of the internal combustion engine.

7. Rail (1) according to one of claims 1 to 5, wherein the rail is configured for adding water to intake lines for drawing air into combustion chambers of the internal combustion engine.

8. Rail (1) according to one of the preceding claims, wherein the rail (1) is formed with a first rail component (5) which is closed by a lid-like second rail component (6).

9. Rail (1) according to claim 8, wherein the first rail component (5) forms a water-bearing cavity (7) of the rail (1) which is closed by the second rail component (6).

10. Rail (1) according to claim 9, wherein a heating element (11) is integrated into the second rail component (6).

11. Rail (1) according to any one of claims 8 to 10, wherein the second rail component (6) is a substantially flat cover.

12. Rail (1) according to one of claims 8 to 11, wherein the first rail component (5) is manufactured at least partially without undercuts.

13. Rail (1) according to one of claims 8 to 12, wherein the first rail component (5) forms at least sectionally a U-shaped profile which forms the rail line (2) and which is closed by the lid-like second rail component (6).

14. Rail (1) according to one of claims 8 to 13, wherein the first rail component (5) and the second rail component (6) are welded together using a plastic welding process.

15. Rail (1) according to one of the preceding claims, wherein connection structures (8) at branch positions (3) for connecting injection valves (4) are formed from plastic and are integrally formed on a bottom side (9) of a first rail component (5) of the rail (1).

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