GB2124298A - Hydrogen fuelled I.C. engine - Google Patents

Abstract

Liquid hydrogen is vaporised and expanded in heat exchanger heated by exhaust gas and pumped to a carburettor where it mixes with air prior to engine induction. Alternatively, gaseous hydrogen, supplied from a tank, is introduced into the carburettor without previous expansion or heating. Descriptive reference is made to associated hardware e.g. tanks, filters, stop valves, expander etc.

Description

SPECIFICATION Liquid hydrogen, gaseous air, internal combustion reciprocating piston engine, and related systems 1. Liquid Hydrogen Fuel Tanks Contents of tanks includes, liquid hydrogen, temperature sensors, volume sensors.

Information from the sensors is carried to a micro processor which works out what approximate pressure is within fuel tank. The information on fuel tank temperature, fuel volume, and tank pressure is then fed from micro processor to instrumentation on flight deck.

Dump of fuel in an emergency situation is provided for by selection and dumping of fuel tanks. As the tanks are located in a compartment in the fuselage, they can be readily ejected from aircraft upon opening of ejection hatch (normally used for access to, and loading of, fuel tanks), decoupling of selected tanks both electrically and fuel wise, then tanks, which are mounted on spring loaded rails can be released. Upon jettison of tanks from aircraft, parachutes on the fuel tanks will open to reduce impact of landing. Each tank is equipped with three parachutes. Upon disconnection of fuel tanks fuel wise, the tank is made to seal against leakage.

2. Filters Filters are of large surface area (40 mm x 40 mm approximately), plate form, or similar surface area multi stage wire form. Large surface area helps to reduce the dynamic load per unit area, thereby helping prevent breakage of filter at very low temperatures. The dynamic load is caused by the flow of liquid hydrogen. Filter will remove any excessively large (in bodily size) contaminants from fuel. Along the flow line that the filters occupy are pressure sensitive membranes which, in the event of one of the filters becoming blocked, there will be a pressure build up on one membrane until it breaks. This will allow fuel to pass through onto the other filter.

Should the second filter become blocked soon after the first, then pressure on another membrane will cause the said membrane to break and allow fuel to flow unfiltered to the rest of the system.

Indication is given, both on flight deck and on filters, that change over and override of filters has occurred when it occurs.

Filters are made easy to change by simple fitment.

3. Stop Valve Stop valve is manually controlled to either switch on or close down fuel supply system. When stop valve is closed, the flow of fuel from fuel tanks is completely stopped.

4. Flow Control Valve The flow control valve can never be completely closed, even with throttle selected fully closed.

Flow control valve meters flow of fuel from fuel tanks to expander. Flow control valve is mechanically linked with controls governing variable speed feed pump, the throttle lever, and the air inlet valve to carburettor, so that upon setting of throttle lever to reduce engine speed, the flow control valve closes down, the variable speed feed pumps slows down, the air control valve to carburettor, thereby ailowing engine to slow down, and the reverse is true for engine speed increase.

The flow control valve is in the form of a sliding plate inside a pressure body.

5. Expander The expander converts liquid hydrogen into warm hydrogen gas. The expander is in the form of a coiled tube, which, at the liquid hydrogen end is small in internal diameter, as the tube goes towards the gas end, the internal diameter increases. The expander tube is mounted within a chamber which is fed with hot exhaust water vapour from the engine. The complete unit is insulated on the outside against heat loss.

The amount of exhaust vapour fed to the expander can be varied according to the temperature of the gas drawn from the expander.

The temperature of the gas is monitored by sensitive Pyrometers. Information from pyrometers is fed to a servo motor via an amplifier circuit. The servo motor alters the amount of exhaust water vapour passed around expander.

6. Variable Speed Feed Pump Variable speed feed pump is used to draw liquid gas through expander by drawing either on gaseous hydrogen or by causing a partial vacuum.

When fuel does reach pump, pump then charges carburettor. The variable speed feed pump is electrically driven.

7. Air Supply to Carburettor for Fuel Mixing Air enters the air supply system either by impeller or simply by engine induction. At low altitude (high atmospheric pressure), the air passes directly into carburettor.

At higher altitudes (lower atmospheric pressure), the impeller is brought into operation to supply the engine with as much air mass as is necessary to keep the engine running.

The impeller is electrically powered, and can be made to vary its output. The impeller is triggered into operation by pressure activated switches, and made to vary its output by pressure sensitive control devices. "Pressure" meaning atmospheric pressure.

The air intake is heated by bleed exhaust to prevent ice forming on air intake.

8. Carburettor On the induction stroke of the engine, air and gaseous hydrogen are drawn into the carburettor from, the air intake and the output from variable speed feed pump.

The two gases are mixed in a swirl chamber, which while remaining stationary, induces the travelling gas to mix by virtue of strategically placed fins in the carburettor tube.

9. Safety Factors a. Engine over heat warning and working temperature indicator.

b. Engine over-speed warning, and revolutions per minute indicator.

c. Expander 'exit' gas temperature warning and indicator, over heat and under heat.

d. Air impeller temperature, and output pressure indicators and warnings.

e. Fuel tanks capacity and temperature indicators and warnings. Warning of over pressurization of fuel tanks is supplied by micro processor when necessary.

f. Variable speed feed pump output pressure indicator.

g. Fuel filter blockage and change over indicators, including "LINE OPEN" function, i.e.

"NO FILTER" indicator.

h. All above indicators and warning devices have built in early warning factors to allow time between shut down of system and stop of system Upon shut down of system the machine does not stop immediately, so upon selection of system shut down, the machine will continue to function for a short period, this is why there must be early warning.

i. CO2 discharge into fuel tanks bay prior to dump of fuel tanks to inhibit fire or explosion. CO2 tanks to be fitted with "armed and ready" indicators, contents indicators, and circuit test facility.

The CO2 extinguisher system is bonded electrically to airframe.

The CO2 fuel tank bay fire extinguisher system has not yet been tested for full function safety, though it is intended that this will be done before flight test.

j. Fuel leak, and fire detection, and extinguishing units are fitted in fire risk areas. All detection and extinguishing equipment is fitted with "armed and ready" check, automatic discharge of extinguishers upon detection of fire, and a manual override on all equipment.

All extinguishers to indicate their contents and indicate (on extinguisher and on flight deck) whether or not they have been discharged, even partly.

k. All aircraft components (systems, structures and Engine) are bonded electrically to airframe, thus complete aircraft systems, airframe and engine are connected electrostatically.

I. The Expander is fitted with a pressure sensor to give indication of pressure and give warning of over-pressurization, and under-pressurization.

10. Other Notes a. Engine is electrically started from an onboard battery.

b. The engine drives two generators for service to systems and for battery charging.

c. The engine can either be air or water cooled.

d. The fuel supply system can be modified to be fed from a primary fuel source of gaseous hydrogen, as opposed to liquid hydrogen. This would mean the exclusion from the supply system of the following.

1. Fuel volume sensors in fuel tank.

2. Micro processor.

3. Fuel tank volume indicator on flight deck.

4. Expander unit.

5. Gas temperature pyrometers (which would monitor temperature of gas from already removed expander).

6. Amplifier circuit and servo motor, which is normally used for variation of exhaust vapour fed to expander chamber.

7. Variable speed feed pump.

Safety Factor Exclusions 1. Expander 'exit gas temperature warning and indicator.

2. Warning of fuel tank over pressurization will not be supplied by micro processor.

3. Expander pressure sensors.

Inclusions to Supply System, for a Primary Source of Gaseous Hydrogen as Follows.

1. Fuel tank pressure sensors and indicators.

Safety Factor Inclusions 1. Fuel tank pressure indicator and over pressure warning are supplied by signals from a transducer in fuel tank.

Statement as to How Liquid Hydrogen System and Engine Differs from Existing Engines and Fuel Supply Systems 1. The invention uses liquid hydrogen as its primary fuel as opposed to other fuels used by other engines and fuel supply systems, i.e. fossil fuels such as oil-petroleum, coal, and others like natural and manufactured gases.

2. The invention uses its own exhaust directly to convert is primary fuel source of liquid hydrogen to a gaseous hydrogen by means of an expander, as described in this specification.

Statement as to How the Gaseous Hydrogen Fuel Supply System and Engine Differs from Existing Engines and Fuel Supply Systems 1. The invention uses gaseous hydrogen as its primary fuel source, as opposed to other fuels used by other engines and their fuel supply systems, i.e. fossil fuels such as oil-petroleum, coal, and natural and manufactured gases.

Claims (3)

CLAIMS 1. I, the undersigned, claim to have invented the Hydrogen-Air, internal combustion, recipicating piston engine, and accompanying supply system as described in the Specification relating to this machine. I wish to protect by patent the above mentioned engine and supply system, which, A. Uses liquid hydrogen as a basic fuel. B. Converts the liquid hydrogen to gaseous hydrogen by means of an exhaust heated expander. C. Mixes the gaseous hydrogen with gaseous air by method of mechanical carburation. D. The mixture of gases then go from carburettor to an internal combustion engine of the recipicating piston type, where it is burnt to produce mechanical energy. E. The above mentioned machine uses its own exhaust to convert its own fuel supply from a liquid to a gaseous form. CLAIMS I the undersigned wish also to protect by patent an internal combustion, recipicating piston engine which uses gaseous hydrogen as its primary fuel as opposed to liquid hydrogen. The main difference between the two machines is in the layout of the supply system. The system utilizing gaseous hydrogen will perform as follows.

1. Gaseous hydrogen from fuel tanks go through filters to remove non solution contamination.

2. Gas hydrogen goes from filter to be regulated, then mixed with air in carburettor.

3. From carburettor the mixed gases go for burning in the engine to produce mechanical energy.