Fuel Cells in Aviation Propulsion

Energy transfer and supply system for hydrogen-powered aircraft that efficiently utilizes liquid hydrogen from low-temperature storage to fuel cells and engines. The system allows liquid hydrogen from a tank to be vaporized, pressurized, and routed to either fuel cells or engines based on demand. This allows flexible utilization of the liquid hydrogen for high-efficiency fuel cell operation or engine heating/combustion. It also involves heat exchangers to absorb waste heat from onboard systems and transfer it to the liquid hydrogen. A controller manages the routing and valves based on demand.

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Configurable fuel cell power system for unmanned aerial vehicles (UAVs) that provides flexibility in power output and center of gravity (CoG) control while enabling modularity and scalability. The system allows stacking multiple fuel cell modules in parallel or series to increase power output. The modules can be repositioned relative to the UAV payload to optimize CoG balance. This enables customizing power and weight distribution for different UAV configurations. The modules can also be connected in parallel to provide redundancy and reliability. The system uses isolation techniques to decouple the fuel cell stack modules from the UAV electronics to prevent ground loops and false grounding issues.

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Aircraft propulsion system using hydrogen fuel for improved efficiency and reduced environmental impact compared to traditional hydrocarbon fuels. The system has a hydrogen tank, heat exchangers, turbo expander, generator, and motor. Hydrogen is supplied from the tank, heated in the aircraft system heat exchanger, and then passed through the turbo expander before entering the engine combustor. The turbo expander captures exhaust energy to drive the generator, which powers the motor to supplement the engine. This allows capturing wasted exhaust energy and using it to generate power, improving overall system efficiency. The cryogenic hydrogen fuel also reduces emissions compared to traditional fuels.

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Aircraft propulsion systems using hydrogen fuel for improved efficiency and reduced emissions. The systems have a main engine with a compressor, combustor, and turbine. Hydrogen is supplied from onboard tanks, passed through remote aircraft systems, and injected into the combustor. A separate turbo expander extracts work from the hydrogen between the tanks and combustor. This reduces fuel pressure/temp before combustion and drives a generator. The generator output powers aircraft systems like wing de-icing. The expander allows using low-volume cryogenic hydrogen instead of heavier liquids/gases.

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Aircraft propulsion system with variable power capability to match flight phase needs, using multiple fuel cell stacks with selective fuel sources. The system has at least two fuel cells, one using hydrogen and air, and another using hydrogen and oxygen. During takeoff and climb, the second cell with oxygen is activated for extra power. This allows higher thrust during demanding stages without overrating the hydrogen fuel cells. The system also uses air as a fuel in one cell, saving hydrogen. The oxygen source can be onboard or from environmental control systems. It enables controllable variable power for aircraft by supplementing hydrogen fuel cells with air or oxygen as needed.

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A hydrogen-oxygen fuel cell hybrid energy system for rockets that integrates propulsion and power generation using the rocket's own propellant. The system involves controlled evaporation of the liquid hydrogen and oxygen propellant to provide hydrogen and oxygen for fuel cells. This eliminates waste and evaporation gas emissions. A fuel cell subsystem generates power, a lithium battery subsystem stores excess power, and an energy management system balances power flows between the fuel cell, battery, and rocket loads. The controlled evaporation is adjusted based on rocket load demands to optimize overall power supply.

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Fuel cell power system for a vehicle like an aircraft with a remote fuel cell stack that receives compressed air from the vehicle's propulsor instead of having an onboard fuel cell. This allows using the vehicle's own compressor to provide air for the fuel cell stack, avoiding the need for a separate air compressor. The hydrogen fuel is supplied from a tank and heated before going to the stack. The fuel cell stack provides electricity to the vehicle. The compressed air from the propulsor is used to cool the fuel cell stack. This configuration enables using hydrogen fuel in aircraft engines without the issues of storing and transporting liquid hydrogen.

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A hydrogen fuel cell system for unmanned aerial vehicles (UAVs) that allows extended flight times and reduces weight compared to traditional lithium-ion batteries. The system uses hydrogen fuel cells instead of batteries. It consists of a control unit, hydrogen supply unit, fuel cell unit, and power management unit. The control unit coordinates the system operation. The hydrogen supply unit stores hydrogen, produces it on demand, and delivers it to the fuel cell unit. The fuel cell unit generates electrical power by reacting hydrogen with oxygen. The power management unit converts the fuel cell output to usable voltage for the UAV. The system allows UAVs to fly longer distances with reduced weight compared to batteries.

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Hydrogen fuel system for aircraft that uses liquid hydrogen stored in tanks to power engines and fuel cells while mitigating weight and safety issues. The system has separate feed lines for engine and fuel cell hydrogen, with heat exchangers to convert liquid to gaseous hydrogen. An accumulator stores pressurized hydrogen drawn from the feed line. A jet pump can also draw vapor from the feed line. This allows efficient hydrogen transfer, conversion, and storage for both propulsion and electricity. The separate engine and fuel cell lines isolate the tanks from each other to prevent cross-contamination and maintain liquid hydrogen integrity.

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Aircraft power system using hydrogen fuel that combines a hydrogen fuel cell and a gas turbine engine for efficient power generation. The system has separate flows of gaseous hydrogen from a supply system to both the fuel cell and the gas turbine. Heat exchangers are used to preheat the hydrogen for the fuel cell and the air for the gas turbine using waste heat streams. This improves efficiency by avoiding the high energy penalty of heating cold hydrogen and air. The fuel cell can also provide electrical power to the aircraft systems instead of the gas turbine engine, further improving efficiency. The method involves operating the fuel cell and gas turbine in parallel with heat exchange between their waste streams.

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A hydrogen fueled high altitude aircraft using a thermodynamic fuel cell system that maximizes efficiency and minimizes environmental impacts. The system compresses inlet air using multiple compressors and cools it using liquid hydrogen to maintain low temperature for the fuel cell. The hydrogen is also compressed and expanded before the fuel cell. The exhaust is cooled to condense water that is collected and expelled as ice. The high efficiency hydrogen conversion enables long range flight with lower fuel volumes. The VTOL aircraft can fly at high altitude with reduced environmental impact.

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Power generation system with improved efficiency using a combination of internal energy extraction from high-pressure hydrogen and conventional fuel cell power generation. The system has a high-pressure hydrogen storage tank, expander-generator to extract internal energy from high-pressure hydrogen, fuel cell stack, and heat exchanger. The expander-generator converts high-pressure hydrogen into low-pressure hydrogen while extracting mechanical energy. This low-pressure hydrogen feeds the fuel cell stack along with air. The heat exchanger uses waste heat or solar energy to preheat the high-pressure hydrogen before expansion. This enables extracting more internal energy from the high-pressure hydrogen. The overall system converts both chemical and internal energy of hydrogen to electrical output.

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Civil aircraft airborne combined fuel cell auxiliary power unit that improves efficiency, reduces pollution, and provides reliable power compared to traditional gas turbine auxiliary power units. The system uses liquid hydrogen fuel, fuel cells, compressors, and turbines to generate electricity. It starts with direct hydrogen combustion in the auxiliary power unit to heat the fuel cell stack quickly. Then, the fuel cell uses hydrogen from the fuel tank and compressed air from the auxiliary power unit to generate electricity. The compressor also drives the turbine to generate more electricity. The turbine exhaust is discharged. This hybrid fuel cell-auxiliary power system provides high efficiency, low pollution, and reliability compared to gas turbine auxiliary power units.

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A hydrogen fuel cell power system for a new layout aircraft that balances energy density and response time requirements for practical aircraft applications. The system uses a hydrogen storage tank as the main energy source with higher energy density compared to batteries. A secondary energy storage battery provides auxiliary power with faster response time. This allows meeting aircraft power needs while leveraging the higher energy density of hydrogen fuel cells. The overall energy density of both tanks is similar to the hydrogen tank's density.

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Aircraft propulsion system using hydrogen fuel for aviation that improves efficiency by selectively coupling multiple turboexpanders to different loads. The system has a main engine with turboexpanders, fuel heat exchangers, and a cryogenic hydrogen tank. Fuel flows through the turboexpanders to extract work before combustion. Loads like generators are selectively connected to turboexpanders based on fuel flow rate to maximize efficiency. This allows using smaller, more efficient expanders for lower flows and larger ones for high loads. A controller controls the turboexpander couplings based on fuel flow.

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Airborne hydrogen fuel cell system for small and medium-sized aircraft that can operate at high altitudes where thin air reduces compressor efficiency. The system uses a hydrogen storage tank, air compressor, fuel cell stack, load motor, and onboard emergency battery. The fuel cell stack provides power to the motor. The compressor generates compressed air for the stack. The storage tank stores excess compressed air from the compressor. At high altitudes, the emergency battery starts the fuel cell stack using stored compressed air from the tank, supplementing the compressor.

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A power management system for fuel cell powered aircraft that improves efficiency by dynamically balancing the power output of the fuel cell and lithium battery. The system uses a power management module to connect the fuel cell, lithium battery, and aircraft motors. It monitors the energy flow and switches between fuel cell and battery power as needed to optimize utilization. During long flights, the fuel cell provides steady power, while the lithium battery supplements during high power maneuvers. This allows efficient use of both power sources.

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Fuel cell system for urban air mobility (UAM) vehicles like drones that enables weight reduction and improved efficiency compared to conventional automotive fuel cell systems. The system distributes components like hydrogen tanks, air supply, cooling, and recovery between the aircraft and ground equipment. This allows omitting components on the aircraft, reducing weight, and enabling ground equipment to manage tasks like hydrogen recovery, air conditioning, and cooling water exchange. It also enables cold recovery of hydrogen expansion heat in the ground equipment to cool the fuel cell stack.

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A hybrid power system for aircraft using hydrogen fuel that allows expanded application scenarios and higher efficiency compared to pure hydrogen fuel cell systems. The system combines a hydrogen fuel cell and a hydrogen internal combustion engine. Gaseous hydrogen is supplied to both subsystems. Air is supplied separately to each subsystem. This allows the internal combustion engine to start and operate in environments where fuel cells may fail, like thin air at high altitude. The hydrogen fuel cell provides high efficiency and zero emissions. The internal combustion engine provides robustness. The hybrid system uses an energy storage battery, air delivery module, and waste gas processing module to connect and manage the subsystems.

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A fault-tolerant fuel cell module for a vertical takeoff and landing aircraft. The module comprises multiple hydrogen fuel cells in a stack, with flow field plates to distribute hydrogen and oxygen. The fuel cells are combined in a modular unit with reduced part count, enabling high power density. Compressed air is supplied by turbochargers. Heat exchangers warm hydrogen extracted from liquid hydrogen fuel.

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