Hydrogen Fuel System for an Internal Combustion Engine
A hydrogen fuel system for an internal combustion engine includes an electrolyzer for generating hydrogen and oxygen gases. A water reservoir in fluid communication with the electrolyzer is provided to maintain the water level in the electrolyzer at an optimum operating level. Hydrogen and oxygen generated by the electrolyzer may be routed to the internal combustion engine to provide the fuel for the engine. Hydrogen and oxygen generated by the electrolyzer which is not consumed by operation of the engine may be stored in pressurized storage tanks for use when required to power the internal combustion engine. Expanders are incorporated in the fuel system of the invention for recovering energy from high pressure high enthalpy process gases for charging the main electrical circuit of the invention. The fuel system includes external ports and electrical outlets for connecting to external water and power sources
This application is a continuation-in-part application of U.S. patent application Ser. No. 11/860,533, filed Sep. 24, 2007, which is a continuation application of U.S. patent application Ser. No. 10/951,290 filed Sep. 27, 2004, now U.S. Pat. No. 7,273,044.
BACKGROUND OF THE DISCLOSUREThe present invention relates generally to a vehicle having an internal combustion engine, and more particularly, to an internal combustion engine powered by hydrogen fuel.
A typical internal combustion engine that is used in automobiles, trucks or other vehicles is generally powered by gasoline or diesel fuel. A gasoline powered internal combustion engine, however, generates pollutants that are expelled into the atmosphere. Pollution from internal combustion engines is a serious problem and many remedies have been proposed. It is known, for example, that adding oxygen into the fuel stream decreases the pollution caused by internal combustion engines. It is also known that hydrogen provides a source of clean energy. Furthermore, the combustion of hydrogen generates water as a by-product that may be electrolyzed to form hydrogen and oxygen gases.
U.S. Pat. No. 6,257,175 (Mosher et al.) describes apparatus for generating hydrogen and oxygen from an electrolysis unit. The gases are gathered separately in the unit and flow to the intake manifold of the engine in separate conduits. U.S. Pat. No. 6,659,049 (Baumert et al.) describes a vehicle with a fuel cell system. Electric power from the vehicle's alternator is used to power an electrolyzer. Hydrogen produced by the electrolyzer is used as fuel for the fuel cell system. The fuel cell system provides electric power for the low power electrical requirements of the vehicle, i.e., lighting, air conditioner, radio, etc., when the engine of the vehicle is not running. While these apparatus contribute to a reduction of pollutant emissions of internal combustion engines, hydrocarbon fuels still provide the primary energy requirements for the vehicles. Pollutant emissions of motor vehicles, however, must still be drastically reduced to have an environmental impact.
It is therefore an object of the present invention to provide an internal combustion engine powered by a hydrogen fuel system.
It is another object of the present invention to provide a vehicle having an electrolysis unit for generating hydrogen and oxygen.
It is another object of the present invention to provide a vehicle fuel system that recycles engine exhaust as input to an electrolysis unit to generate hydrogen and oxygen which may be re-used as fuel to power the vehicle.
It is another object of the present invention to provide a vehicle fuel system having removable storage capacity for hydrogen or oxygen generated by an electrolysis unit.
It is another object of the present invention to provide a vehicle fuel system utilizing expanders to generate electric power from high pressure gases.
SUMMARY OF THE INVENTIONIn accordance with the present invention, a hydrogen fuel system for an internal combustion engine includes an electrolyzer for generating hydrogen and oxygen gases. The exhaust of the engine may be recycled through the electrolyzer where it is converted to hydrogen and oxygen which may be used as fuel for the internal combustion engine. A water reservoir in fluid communication with the electrolyzer is provided to maintain the water level in the electrolyzer at an optimum operating level. Hydrogen and oxygen generated by the electrolyzer may be routed to the internal combustion engine to provide the fuel for the engine. Hydrogen and oxygen generated by the electrolyzer which is not consumed by operation of the engine may be stored in pressurized storage tanks for use when required to power the internal combustion engine. Expanders are incorporated in the fuel system of the invention for lowering the pressure of the pressurized hydrogen and oxygen to the engine pressure requirements and for utilizing the potential energy stored within the pressurized gases to provide a portion of the electrical power requirement of the fuel system. The fuel system includes external ports and electrical outlets for connecting to external water and power sources.
BRIEF DESCRIPTION OF THE DRAWINGSSo that the manner in which the above recited features, advantages and objects of the present invention are attained can be understood in detail, a more particular description of the invention briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
It is noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
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The vehicle 11 powered by the fuel system of the present invention is equipped with conventional components such as an alternator 12, a battery 14 and other electrical devices. As in conventional vehicles, the alternator 12 produces electric power while the engine 10 is operating. The battery 14 is used for starting the engine 10, storing the output of the alternator 12 and powering the electrical components of the vehicle 11 while the engine 10 is not operating.
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Exhaust vapor exits the engine 10 at a high temperature and moderate pressure. The engine exhaust is routed through a conduit 19 to an expander 21 where the pressure of the exhaust vapor is decreased. The expander 21 is electrically coupled to the electrolyzer 30 via a power line 23. The expander 21 converts the potential energy stored within the engine exhaust vapor into electric power used to provide part of the power requirements of the electrolyzer 30.
The exhaust vapor from the engine 10 flows through the expander 21 at a reduced pressure and is channeled by a conduit 16 to an air-cooled condenser 18. The exhaust from the engine 10 contains hydrogen, oxygen, water vapor and potential pollutants, such as NO x, at a temperature of about 1000° F. A temperature element or sensor 25 located in the conduit 16 upstream from the condenser 18 measures the temperature of the engine exhaust entering the condenser 18 and communicates the exhaust temperature value to a temperature controller 27 which operates a water valve 20 connected to the conduit 16 upstream of the temperature element 25. The valve 20 is connected by a water supply line 22 to a water reservoir 26. In response to the temperature of the engine exhaust, the controller 27 operates the valve 20 in a desired manner to spray water into the exhaust conduit 16, and thereby cool the engine exhaust vapor to the water saturation point prior to entering the condenser 18, where it is condensed into water. Cooling the engine exhaust reduces the backpressure on the engine 10 as the exhaust vapor passes through the condenser 18. A reduction in engine backpressure improves engine performance through increased horsepower availability. The condensed water exiting the condenser 18 is pumped by a pump 24 to the water reservoir 26. Any gases formed in the condenser 18 are first channeled through a catalytic converter 31 for removal of any potential pollutants and then vented to the atmosphere.
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When the vehicle 11 is operating, electric power to operate the electrolyzer 30 for production of hydrogen and oxygen is provided by an electric circuit comprising the alternator 12, the battery 14 and the expanders operatively connected to the electrolyzer 30. When the vehicle 11 is not operating, hydrogen and oxygen is generated by the electrolyzer 30 by connecting the vehicle 11 to an external power source, such as a standard residential electrical outlet. The vehicle 11 is provided with an electrical outlet 36 for connection to the external power source. The outlet 36 is electrically coupled to the electrolyzer 30, hydrogen compressor 38 and water pump 40 housed in the vehicle 11, thereby forming a second electric circuit for operating the electrolyzer 30.
Hydrogen produced by the electrolyzer 30 when the vehicle 11 is not operating and connected to an external power source is routed via conduit 41 to the compressor 38 and then to the hydrogen storage tank 42. The hydrogen is pressurized by the compressor 38 and stored in the storage tank 42 as pressurized vapor. The storage tank 42 is removable so that it may be replaced with a spare tank of hydrogen when the tank 42 becomes empty and an external electrical power source may not be readily available to recharge the tank 42.
Hydrogen conduit 48 connects the pressurized hydrogen storage tank 42 to the intake manifold of the engine 10. Hydrogen which exits the storage tank 42 at a high pressure is routed through the expander 50 where the pressure of the hydrogen is decreased to the required engine intake pressure. The expander 50 is electrically coupled to the electrolyzer 30 by a power line 52. The expander 50 converts the potential energy stored within the pressurized hydrogen into electric power used to power the electrolyzer 30.
Periodically, the water reservoir 26 will require replenishment. The vehicle 11 is provided with a water pump 40 and a water port 44 in fluid communication with the water reservoir 26 via a water line 46. The port 44 provides access for adding water to the reservoir 26 as is required. Tap water may be used to fill the reservoir 26 as needed. However, distilled water may also be used if desired. Electrolyte for aiding the electrolysis process may also be added through the port 44.
The fuel system of the present invention may be retrofit into an existing vehicle or incorporated in a new vehicle design. While the use of hydrogen fuel for an internal combustion engine is known and understood in the art, the hydrogen fuel system of the present invention utilizes expanders to recover power from pressurized hydrogen and oxygen to supplement the electric power available to operate the electrolyzer and recycles the engine exhaust to produce more hydrogen and oxygen for fuel and thereby extend the driving range of the vehicle. In the operation of a vehicle 11 equipped with the fuel system of the present invention illustrated in
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The engine exhaust vapor exits the engine 100 and passes through a heat exchanger 112. The engine exhaust is then routed through an expander 114 where the pressure of the exhaust vapor is decreased. The expander 114 recovers energy as electrical power for charging the main electrical circuit. The expander 114 takes high pressure high enthalpy process gases and reduces their pressure thereby capturing the energy as mechanical energy and converting that to electricity. The engine exhaust then passes through a catalytic converter 116 and is discharged to the atmosphere. The temperature and flow rate of the engine exhaust are monitored by a sensor 115 located in the engine exhaust line between the engine 100 and the heat exchanger 112. The sensor 115 transmits the engine exhaust temperature and flow rate to the central processor. Combustion using pure oxygen increases the engine exhaust temperature which may be reduced by increasing the air flow to the engine 100.
Passage of the engine exhaust through the heat exchanger 112 generates steam from water routed through the heat exchanger 112 to a condensing turbine 118. The turbine 118 converts mechanical energy to electrical energy. Electrical energy is recovered from the turbine 118 for charging the main electrical circuit. Steam condensate exiting the condensing turbine 118 is routed through an air-cooled radiator 120 and then to a water tank 122 that is maintained at atmospheric pressure. Any excess water in the heat exchanger 112 is routed through an overflow line 113 to the water tank 122.
The atmospheric water tank 122, when full, holds enough water for about two weeks travel under normal vehicle usage and driving conditions. Water from the tank 122 is pumped by a pump 124 to a pressurized water tank 126. Water from the pressurized tank 126 is routed under temperature control to the heat exchanger 112. The flow rate of water to the heat exchanger 112 from the water tank 126 is regulated by a controller 117 operatively connected to a flow valve 121. A sensor located in the engine exhaust line between the heat exchanger 112 and expander 114 transmits exhaust temperature values to the controller 117. By monitoring the engine exhaust temperature, the water flow to the heat exchanger 112 may be optimized so that steam exiting the heat exchanger 112 is relatively water free as it enters the condensing turbine 118.
The water level in the pressurized water tank 126 is monitored and maintained at a predetermined level. The tank 126 supplies water under pressure to the heat exchanger 112 and the electrolyzer 108. The water level in the electrolyzer 108 is maintained between a maximum and minimum level to ensure proper operation of the electrolyzer 108 and sufficient water flow to the heat exchanger 112. Sensors 125 and 151 monitor the water level in the tank 126 and the electrolyzer 108, respectively. The sensors 125 and 151 are operatively connected to a water level control valve 129 which is operatively connected to the tank 126 for regulating the supply of water to the tank 126 and electrolyzer 108. Excess water in the water tank 126 is re-circulated via a water line 152 back to the atmospheric tank 122 by operation of a solenoid valve 123.
The electrolyzer 108 generates pure oxygen and hydrogen from water. Electrical power for operation of the electrolyzer 108 is provided by the main electrical circuit. Oxygen generated by the electrolyzer 108 is routed through an expander 128 where it is let down to the engine intake pressure. The expander 128 recovers energy as electrical power for charging the main electrical circuit. All the oxygen generated by the electrolyzer 108 is used by the engine 100 when it is running. The oxygen flow rate to the engine 100 is monitored by the central processor. The higher the concentration of oxygen in the engine 100, the less the concentration of nitrous oxides will be formed. When the engine 100 is off but connected to an outside electrical source, any oxygen generated by the electrolyzer 108 is mixed with air and vented through a vent valve to the atmosphere at a safe location.
Hydrogen from the electrolyzer 108 is under pressure control. The throttle 138 regulates the flow of hydrogen to the engine 100. The hydrogen pressure in the hydrogen flow line 133 is monitored by a pressure sensor 135. When hydrogen pressure in the hydrogen flow line 133 reaches a pressure higher than is required to meet the hydrogen fuel requirements of the engine 100, a pressure control valve 134 opens and a hydrogen compressor 136 is activated and hydrogen is routed to storage tank 110. When storage tank 110 is full, solenoid valve 129 opens and hydrogen is routed to storage tank 130. When storage tank 130 is full, solenoid valve 131 opens and hydrogen is routed to storage tank 140. When solenoid valve 131 opens a visual and/or audible indicator alerts the driver that hydrogen is being routed to storage tank 140. When storage tank 140 is full, the control valve 134 and hydrogen compressor 136 shut off. A pressure relief valve 149 is mounted on storage tank 140 in the event storage tank 140 is over-pressurized. A visual and/or audible indicator alerts the driver that hydrogen storage tanks 110, 130 and 140 are full. The vehicle can be run full range with the control valve 134 closed and the hydrogen compressor 136 off. It will be recognized by those skilled in the art that the number of hydrogen storage tanks is not critical to the present invention. It is contemplated that one or more hydrogen storage tanks may be included in the design of the fuel system shown in
If the hydrogen generated by the electrolyzer 108 is not sufficient for the hydrogen fuel requirements of the engine 100, the pressure sensor 135 transmits the low hydrogen pressure in the line 133 to the central processor and the flow control valve 137 connecting the hydrogen storage tanks to the hydrogen flow line 133 opens. Solenoid valve 127 in the hydrogen flow line connecting hydrogen storage tank 110 to the flow control valve 137 opens simultaneously with the flow control valve 137. Hydrogen from the storage tank 110 supplements the supply of hydrogen to meet the hydrogen fuel requirements of the engine 100. When hydrogen storage tank 110 is empty, solenoid valve 127 closes and solenoid valves 141 and 143 open sequentially and supply hydrogen from the tanks 130 and 140 to the engine 100. Upon opening solenoid valve 143, an indicator light alerts the driver that hydrogen from the last tank 140 is being supplied to the engine 100 and that the hydrogen storage tanks 110, 130 and 140 will need to be recharged soon if the hydrogen requirements of engine 100 continue to exceed the hydrogen output of the electrolyzer 108. When storage tank 140 is empty, the control valve 137 and solenoid valve 143 close. Actuation of the hydrogen flow control valves and the solenoid valves occurs virtually instantaneously and is controlled by the central processor.
The driver may continue to drive the vehicle at a speed that does not require more hydrogen than the output of the electrolyzer 108 to operate the engine 100 until reaching an electrical and water source to recharge the hydrogen storage tanks and fill the water tank 122. In the event an electric source is not available, the hydrogen tanks may be removed and replaced with pre-filled hydrogen cylinders.
Electrical power may also be recovered from the braking assemblies at each wheel and from wind turbines. Each wheel recovers kinetic energy upon braking that may be converted to electric power for charging the main circuit. Wind turbines with generators placed in the front grill of the vehicle or just off the trunk may be activated by applying the brakes. The wind turbines will generate electrical power for charging the main circuit.
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While preferred and alternate embodiments of the invention have been shown and described, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims
1. A fuel system for an internal combustion engine, comprising:
- (a) an air intake port open to the atmosphere;
- (b) an electrolyzer for generating hydrogen and oxygen;
- (c) a water reservoir in fluid communication with said electrolyzer;
- (d) electric circuit means for providing electric power to said electrolyzer;
- (e) conduit means for routing pressurized oxygen and hydrogen to said engine; and
- (f) means for lowering the pressure of said pressurized oxygen and hydrogen to the engine intake pressure.
2. The fuel system of claim 1, including a heat exchanger for recovering heat energy from the engine exhaust.
3. The fuel system of claim 2, including a steam turbine for recovering energy from steam generated by said heat exchanger.
4. The fuel system of claim 3, including an air cooled radiator for cooling steam vapor generated by said heat exchanger.
5. The fuel system of claim 2, including a catalytic converter disposed in said engine exhaust conduit for filtering pollutants from exhaust vapor generated by said engine.
6. The fuel system of claim 1, wherein said conduit means includes a first conduit for routing hydrogen from said electrolyzer to said engine and a second conduit for routing oxygen from said electrolyzer to said engine.
7. The fuel system of claim 1 including a fuel mixture comprising pure hydrogen and pure oxygen mixed with air.
8. The fuel system of claim 1 wherein kinetic energy from regenerative braking is converted to electric power for charging said electric circuit means.
9. The fuel system of claim 8 including wind turbines for generating electric power for charging said electric circuit means.
10. The fuel system of claim 8 including at least one hydrogen storage tank containing pressurized hydrogen operatively connected to said engine;
Type: Application
Filed: Dec 12, 2007
Publication Date: May 15, 2008
Inventors: STEPHEN FLESSNER (Sugar Land, TX), Eric Flessner (Sugar Land, TX)
Application Number: 11/955,371
International Classification: F02B 43/12 (20060101); F01N 3/10 (20060101); F01N 5/02 (20060101); F02B 51/04 (20060101); F17C 1/00 (20060101); F03D 9/00 (20060101); H02P 3/00 (20060101); F01P 1/00 (20060101); F01D 1/00 (20060101);