A Hydrogen Gas Fuel And Management System For An Internal Combustion Engine Utilizing Hydrogen Gas Fuel #5,293,857

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ABSTRACT:

A gas fuel for an internal combustion engine comprising a mixture of gases having a proportion of hydrogen to oxygen of approximately 2:1 and a regulated density of the hydrogen component of the mixture such that the burn rate of the mixture approximates that of a fossil fuel and a system for maintaining the foregoing gas fuel mixture and characteristics in an internal combustion engine.

Hydrogen has long been regarded as an efficient, abundant and potentially non-polluting energy source. Yet despite such desirable attributes, hydrogen has not been widely, or practically, applied in applications where the use of hydrogen as a fuel is self-evidently desirable, such as in motor vehicles powered by internal combustion engines. In part, practical use of hydrogen is inhibited by difficulties in the safe transmission of the gas. Hydrogen has an inherent high volatility and a correspondingly rapid dispersion characteristic in other gas mixtures such as the atmosphere. Further, it is difficult to control the distribution of a hydrogen gas fuel and to maintain consistent combustion characteristics for a hydrogen gas fuel, particularly in a motor vehicle internal combustion engine.

PRIOR ART:

In my present application, I describe an integrated fuel gas management system that enables hydrogen to be efficiently, reliably and safely used as a fuel gas in an internal combustion engine having a configuration de- rived from conventional engines fueled by a fossil fuel, such as gasoline, diesel or other petroleum or hydrocarbon derivative. In the prior art, significant effort directed towards the utilization of hydrogen as a vehicle fuel has attempted to devise a hydrogen powered internal combustion engine that emulates the characteristics of a conventional hydrocarbon fueled (gasoline, diesel, propane, methanol, etc.) engine system. While such an extension of an existing technology to a hydrogen fuel appears logically proper, such prior art techniques have not fully considered: (1) that the volatility, or "burn rate", of hydrogen is many times greater than that of a fossil fuel, and (2) that the combustion "window" for hydro- gen in an oxygen containing atmosphere is exceedingly narrow, and is considerably narrower than that of a fossil fuel.

A fuel such as gasoline or diesel oil will satisfactorily perform and support combustion over a wide range of fuel mixtures having different proportional quantities of oxygen. Hydrocarbon fuels typically support engine speeds over a wide range in an internal combustion engine because of its broad combustion envelope; hydrogen in contrast, will combust satisfactorily only when a hydrogen/oxygen mixture in the ratio of 2:1 is present. This factor makes combustion cycle development for hydrogen fuel a critical art in which the hydrogen burn rate (equated to power output of the engine) and the combustion mixture containing the hydrogen fuel must be carefully regulated over the entire RPM operating range of an engine so that combustion is efficiently supported over the range. The invention herein provides a gas fuel for an internal combustion engine comprising a mixture of gases including hydrogen, oxygen, and other gases that are not combustible with hydrogen in which the mixture includes a proportion of hydrogen to oxygen of approximately 2:1' and a predetermined density of hydrogen within the mixture gases such that the burn rate of the mixture approximates that of a fossil fuel.

There is further management system provided for a fuel gas mixture containing hydrogen that is introduced as a fuel to an internal combustion engine that consists of means and process for monitoring the composition of a fuel gas mixture introduced into the engine such that the proportion of hydrogen to oxygen in the mixture is approximately 2:1; and means and process for modulating the density of the hydrogen component of the introduced fuel gas mixture by the addition of other non- combustible gases to the mixture such that the burn rate of the fuel gas mixture approximates that of a fossil fuel. In the management system, apparatus for the distribution of the fuel gas mixture containing a hydrogen gas component is utilized which is formed from a plurality of conduits having an internal diameter of 0.015 to 0.025 inch intrinsically formed in an otherwise solid member. In addition, the system includes a means and process for the mixing of a proportion of the exhaust gas of the engine into the fuel gas mixture introduced into the engine to provide modulation for the hydrogen in the fuel mixture. Thus, in a further aspect the invention is an improvement to a hydrogen fueled internal combustion engine that includes means and process for modulating the density of the hydrogen component of a fuel gas mixture introduced into the engine such that the burn rate of the fuel gas mixture containing hydrogen is reduced to the approximate burn rate of a fossil fuel. This means and process includes mixing a hydrogen containing fuel gas with at least one of ambient air and exhaust gas from the engine. These features of the invention are explained herein with reference to the figures.

OBJECTS:

It is an object of this invention to overcome such difficulties and to provide a fuel gas management and delivery system for internal combustion engines that utilize hydrogen as a fuel. The system includes a safe and effective distribution means for supplying a hydro- gen fuel to an internal combustion engine, means for fuel injection applications of hydrogen fuel in such an engine, means for controlling the burn rate of hydrogen for the efficient use of a hydrogen fuel gas, and means for overcoming prior art problems of engine shut down caused by an over-enrichment of hydrogen in the fuel supply to the engine.
In particular, when hydrogen gas fuel is used in a motor vehicle internal combustion engine, an over-enrichment of the hydrogen component of the fuel gas injected into the engine frequently occurs and results either in (1) an engine shut down, because of the narrow combustion window (a term defined hereinafter) for hydrogen, or (2) a significant waste of the "over-enriched" portion of the fuel not combusted—the fuel is expelled in the engine exhaust. In prior art attempts, mechanical meters, valves and switches that were conventionally used in engine fuel systems for petroleum based, fossil fuels were too slow to adapt to engine conditions. Similarly, prior art system included processors that were intended to control the engine in view of predetermined operating parameters with little regard for engine effects caused by the injection of a hydrogen fuel. As a result over-enrichment of hydrogen in the fuel/combustion mixture consistently remains a problem in the development of a hydrogen fueled internal combustion engine. Conventional hydrogen fueled engines are prone to shut down and do not smoothly operate over the extended range of engine speeds considered desirable and necessary in a motor vehicle.
It is accordingly an object of this invention to provide a fuel distribution system for a hydrogen fueled internal combustion engine that reduces the problem of fuel over-enrichment and provides a smooth operating characteristic for engine speeds required in conventional use.
It is also an object to provide a "tuned" combustion system, adaptable not only for hydrogen, but also to other fuel stocks by which optimum combustion characteristics are maintained for the fuel over the operating range of the engine.
And it is a further object to provide an integrated operating system including fuel generation and control means for a hydrogen fueled internal combustion engine.
These and other objects of the invention will become evident to those of skill in the art when the following description of the preferred embodiment is considered in conjunction with the drawings in which:

DESCRIPTION OF DRAWINGS:

FIG. 1 shows the combustion envelope of hydrogen compared to the combustion envelope of gasoline and illustrates a goal achieved by the invention in maintaining an optimum and uniform combustion rate for hydrogen throughout the effective range of engine RPM. As used herein, the "combustion envelope" refers to the range within which combustion of a fuel gas is possible, given a predetermined quantity of combustible fuel and its ratio to the combustion media, i.e. oxygen.)

FIG. 2 is a block diagram of a combustion management system for a hydrogen containing fuel gas mixture that is injected into a combustion chamber, showing the interrelationship of system management controls with various engine parameters.

FIG. 3 illustrates the physical arrangement of a hydrogen fuel gas control means and injection system for the regulation of fuel gas transmitted to an engine combustion chamber.

FIG. 4 shows an air gas processor useful in the system of the invention in a cross-sectional side view; FIG. 4A shows a top plan view; and FIG. 4B is a bottom view.

FIG. 5 shows a "quenching conduit" for the safe distribution of a hydrogen fuel in the engine environment, and FIGS. 5A and 5B shows alternative cross section configurations for said conduit.

FIG. 6 figuratively represents the modulating effect upon hydrogen gas characteristics of other non-combustible gases included in a fuel gas mixture containing hydrogen in accord with the invention and its fuel gas management system.

FIG. 7 shows the electron extractor circuit used in the air processor section to ionize and maintain the ionization of introduced air gas.