Hydrogen Direct Injection System and Method for Lubricating a Fuel Injector of a Hydrogen Direct Injection System

Abstract

An embodiment hydrogen direct injection system for an internal combustion engine of a motor vehicle includes a fuel line and a fuel injector configured to inject hydrogen fuel into a combustion chamber of the internal combustion engine, wherein the fuel injector is configured to receive the hydrogen fuel via the fuel line and to receive water via the fuel line, and wherein the water is configured to lubricate the fuel injector.

Claims

1. A hydrogen direct injection system for an internal combustion engine of a motor vehicle, the system comprising: a fuel line; a fuel injector configured to inject hydrogen fuel into a combustion chamber of the internal combustion engine, wherein the fuel injector is configured to receive the hydrogen fuel via the fuel line and to receive water via the fuel line, and wherein the water is configured to lubricate the fuel injector; and a water generator configured to generate the water by combining hydrogen with oxygen, wherein the water generator is fluidly connected to the fuel line of the fuel injector to deliver the generated water as a lubricant for the fuel injector and wherein the water generator comprises a fuel cell for combining the hydrogen with the oxygen.

2. (canceled)

3. The system according to claim 1, further comprising a fuel rail fluidly connected with the water generator and the fuel line of the fuel injector to deliver the hydrogen fuel together with the generated water from the water generator to the fuel line.

4. (canceled)

5. The system according to claim 1, wherein the water generator comprises a water pump configured to deliver the generated water to the fuel injector, wherein the water generator is configured to use electricity produced by the fuel cell to power the water pump.

6. The system according to claim 1, wherein the water generator comprises a chemical reactor configured to combine the hydrogen with the oxygen in a chemical reaction.

7. The system according to claim 1, wherein the water generator comprises a condenser configured to generate the water as a liquid.

8. The system according to claim 1, wherein the water generator is configured to receive the hydrogen from a hydrogen fuel tank of the motor vehicle.

9. The system according to claim 1, wherein the water generator is configured to receive the oxygen as air from a surrounding environment.

10. A motor vehicle comprising: a vehicle body; an internal combustion engine mounted in the vehicle body; a fuel line; a fuel injector configured to inject hydrogen fuel into a combustion chamber of the internal combustion engine, wherein the fuel injector is configured to receive the hydrogen fuel via the fuel line and to receive water via the fuel line, and wherein the water is configured to lubricate the fuel injector; and a water generator configured to generate the water by combining hydrogen with oxygen, wherein the water generator is fluidly connected to the fuel line of the fuel injector to deliver the generated water as a lubricant for the fuel injector and wherein the water generator comprises a fuel cell for combining the hydrogen with the oxygen.

11. (canceled)

12. A method comprising: injecting hydrogen fuel with a fuel injector into a combustion chamber of an internal combustion engine of a motor vehicle, wherein the fuel injector receives the hydrogen fuel via a fuel line and wherein the fuel injector further receives water via the fuel line, the water being a lubricant for the fuel injector; and generating the water with a water generator by combining hydrogen with oxygen, wherein the generated water is delivered to the fuel line of the fuel injector as the lubricant for the fuel injector, wherein the water generator comprises a fuel cell that combines the hydrogen with the oxygen.

13. (canceled)

14. The method according to claim 12, further comprising delivering, by a fuel rail, the hydrogen fuel and the generated water from the water generator to the fuel line of the fuel injector.

15. (canceled)

16. The method according to claim 12, wherein the water generator comprises a water pump that delivers the water to the fuel injector, wherein the water generator uses electricity produced by the fuel cell to power the water pump.

17. The method according to claim 12, wherein the water generator comprises a chemical reactor that combines the hydrogen with the oxygen in a chemical reaction.

18. The method according to claim 12, wherein the water generator comprises a condenser that generates the water as a liquid.

19. The method according to claim 12, wherein the water generator receives the hydrogen from a hydrogen fuel tank of the motor vehicle.

20. The method according to claim 12, wherein the water generator receives the oxygen as air from a surrounding environment or from an oxygen tank of the motor vehicle.

21. The system according to claim 1, wherein the water generator is configured to receive the oxygen from an oxygen tank of the motor vehicle.

22. The motor vehicle according to claim 10, further comprising a fuel rail fluidly connected with the water generator and the fuel line of the fuel injector to deliver the hydrogen fuel together with the generated water from the water generator to the fuel line.

23. The motor vehicle according to claim 10, wherein the water generator comprises a water pump configured to deliver the generated water to the fuel injector, wherein the water generator is configured to use electricity produced by the fuel cell to power the water pump.

24. The motor vehicle according to claim 10, wherein the water generator comprises a chemical reactor configured to combine the hydrogen with the oxygen in a chemical reaction.

25. The motor vehicle according to claim 10, wherein the water generator comprises a condenser configured to generate the water as a liquid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are included to provide a further understanding of embodiments of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of embodiments of the invention. Other embodiments of the present invention and many of the intended advantages of embodiments of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. In the figures, like reference numerals denote like or functionally like components, unless indicated otherwise.

[0036] FIG. 1 schematically depicts a hydrogen direct injection system according to an embodiment of the invention.

[0037] FIG. 2 schematically depicts a hydrogen direct injection system according to another embodiment of the invention.

[0038] FIG. 3 schematically depicts a hydrogen direct injection system according to yet another embodiment of the invention.

[0039] FIG. 4 shows a flow diagram of a method for lubricating a fuel injector of one of the direct injection systems of FIGS. 1 to 3.

[0040] FIG. 5 schematically shows a motor vehicle comprising one of the direct injection systems of FIGS. 1 to 3.

[0041] Although specific embodiments are illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of embodiments of the present invention. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0042] The following reference identifiers may be used in connection with the accompanying drawings to describe embodiments of the invention.

TABLE-US-00001 1 fuel injector 2 water generator 3 fuel line 4 fuel rail 5 fuel cell 6 chemical reactor 7 condenser 8 control valve 9 electric line 10 direct injection system 11 water pump 12 internal combustion engine 100 motor vehicle A air H2 hydrogen O2 oxygen N2 nitrogen H20 water M method M0, M1 method steps

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0043] FIGS. 1 to 3 schematically depict hydrogen direct injection systems 10 according to three different embodiments of the present invention. FIG. 4 shows a flow diagram of a method M for lubricating a fuel injector 1 of the direct injection systems 10 of FIGS. 1 to 3, while FIG. 5 schematically shows a motor vehicle 100 equipped with one of the direct injection systems of FIGS. 1 to 3.

[0044] The systems 10 and the method M are provided as a pragmatic solution for realizing hydrogen direct injection in an internal combustion engine with adequate and sufficient lubrication of the hydrogen fuel injectors 1 to avoid excessive wear and premature aging of the system components. The solution is based on the insight that water can be used as lubricant in the case of hydrogen combustion in order to avoid the potential negative drawbacks of oil or similar alternative lubricants. The water used as a lubricant is produced during operations on the basis of the hydrogen fuel stored in a fuel tank of the motor vehicle 100, as will be described now.

[0045] All three depicted hydrogen direct injection systems 10 comprise one or several fuel injectors 1 configured to inject hydrogen fuel into a combustion chamber of the internal combustion engine (ICE) 12. Each fuel injector 1 is configured to receive hydrogen as fuel via a fuel line 3 as well as water for lubrication.

[0046] The systems 10 further comprise a water generator 2 configured to generate the water for lubrication by combining hydrogen with oxygen. To this end, the water generator 2 is fluidly connected to the fuel line 3 of the fuel injector 1 to deliver the generated water as lubrication for the fuel injector 1.

[0047] The hydrogen used for the water generation is taken from the same hydrogen tank of the motor vehicle 100 (see FIG. 5) that the hydrogen fuel is also taken from to supply the internal combustion. The oxygen on the other hand can be supplied from a dedicated oxygen tank (also not shown) and/or be received as air from the environment (thereby avoiding the need for a dedicated additional tank on the vehicle 100). The specific amounts may be controlled by respective control valves 8, e.g., electric valves.

[0048] In the embodiments of FIGS. 1 and 2, the water generator 2 comprises a chemical reactor 6 for combining the hydrogen with oxygen, while a fuel cell 5 is employed for this purpose in the embodiment of FIG. 3. All three embodiments comprise a condenser 7 for liquifying the produced water.

[0049] In the embodiment of FIG. 1, the chemical reactor 6 uses pure oxygen from a separate small tank (not shown) together with ordinary hydrogen fuel from the fuel tank to produce, with use of the condenser 7, liquid water, which is then delivered together with non-reacted hydrogen to a fuel rail 4, which in turn supplies the fuel line 3 of the fuel injector 1. The reaction of both components can thus be written as:

[00001]$\begin{array}{cc}{nH}_2+O_2+\mathrm{catalyst}.fwdarw.2H_{2}O+\left(n-2\right)H_2+\mathrm{catalyst}& \mathrm{Equation}1\end{array}$$\begin{array}{cc}{H}_{2}O/H_2=2/\left(n-2\right);n>2& \mathrm{Equation}2\end{array}$

[0050] The configurations shown in the embodiments and drawings described in this specification are preferred examples of embodiments of the disclosure, and there may be various modifications that may replace the embodiments and drawings in this specification at the time of filing of the present application.

[0051] Water is already sufficient to reduce the inner temperatures within the injector 1 and to increase the inner lubrication. A further side-effect of the water is a decrease of the combustion temperature that simultaneously decreases NOx-emissions, which is the only main pollutant which emits from a H2-ICE. Pre-ignition and knocking can be prevented by adding fluid water to the fuel/air mixture in the combustion chamber.

[0052] In the embodiment of FIG. 2, the chemical reactor 6 uses air from the environment as an oxygen source. Non-reacted nitrogen from the air can then be separated and released into the environment (upper right in FIG. 2). In this exemplary embodiment, the generated water is delivered directly into the fuel line 3 of the fuel injector 1 by a water pump 11, thereby bypassing the fuel rail 4, which is still supplied with hydrogen from the hydrogen tank. The reaction of the components can thus be written as follows in this case:

[00002]$\begin{array}{cc}2H_2+O_2+{xN}_2+\mathrm{catalyst}.fwdarw.2H_{2}O+{xN}_2+\mathrm{catalyst}& \mathrm{Equation}3\end{array}$

[0053] In the embodiment of FIG. 3, the water is produced by the fuel cell 5. The fuel cell 5 reacts H2+ and O2 within each layer of a membrane assembly and produces H2O. The water is then used for lubricating and cooling the fuel injector 1. Also in this case, the water is directly delivered to the fuel line 3 of the fuel injector 1. The reaction can be written as follows:

[00003]$2H_2+O_2+{xN}_2+\mathrm{catalyst}.fwdarw.2H_{2}O+{xN}_2+\mathrm{catalyst}$

[0054] The electric energy produced in the fuel cell 5 is used to actuate the water pump 11, which delivers the water to the fuel line 1. Hence, the additional benefit of this embodiment is that generated electric power can be used for auxiliaries like the water pump 11 or other electric devices. Hydrogen for combustion is delivered to the injector 1 through the primary injector inlet via the fuel rail 4.

[0055] A corresponding method M as schematically depicted in FIG. 4 thus comprises generating water with the water generator 2 by combining hydrogen with oxygen and delivering the generated water to the fuel line 3 of the fuel injector 1 for lubrication (M0) and injecting hydrogen fuel with the fuel injector into the combustion chamber of the internal combustion engine 12 (M1).

[0056] In the foregoing detailed description, various features are grouped together in one or more examples with the purpose of streamlining the disclosure. It is to be understood that the above description is intended to be illustrative and not restrictive. It is intended to cover all alternatives, modifications, and equivalents of the different features and embodiments. In particular, although a hydrogen powered vehicle having a hydrogen combustion engine and a hydrogen injector have been described in the embodiments above, this principle can readily be applied to a natural gas powered vehicle using a natural gas, such as, e.g., methane, as fuel and having a natural gas combustion engine and a natural gas injector. Many other examples will be apparent to one skilled in the art upon reviewing the above specification. The embodiments were chosen and described in order to explain the principles of embodiments of the invention and its practical applications, to thereby enable others skilled in the art to utilize embodiments of the invention and various embodiments with various modifications as are suited to the particular use contemplated.