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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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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Aircraft engine system using hydrogen fuel for improved efficiency and reduced emissions. The engine has a compressor, combustor, and turbine section. Hydrogen fuel is supplied from an onboard tank through heat exchangers before combustion. The engine has a low bypass ratio (under 20) and specific size-diameter ratio for the fan. This allows high hydrogen flow and efficiency. The hydrogen fueling allows using hydrogen-based fuels like hydrogen or methane in aviation engines, which have lower emissions than hydrocarbon fuels. The heat exchangers preheat the hydrogen for better combustion.

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Aircraft propulsion system using hydrogen fuel for improved efficiency and reduced emissions. The system has an aircraft hydrogen tank and a heat exchanger on the aircraft. The heat exchanger preheats the hydrogen before sending it to a heat exchanger on the engine. Another heat exchanger on the engine further preheats the hydrogen before combustion. This multiple stage preheating reduces engine heat loss by warming the hydrogen before combustion. The preheated hydrogen is then combusted in the engine's burner instead of traditional hydrocarbon fuels. The hydrogen-only fuel system allows using hydrogen as a cleaner fuel in turbine engines compared to hydrocarbons.

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System for refueling hydrogen fuel cell-powered aircraft with minimum boil-off and leakage of cryogenic hydrogen fuel. The system uses a compressor to pressurize ambient temperature hydrogen from a storage source, and a heat exchanger to absorb excess compression heat. This heat is converted to usable energy to power the aircraft. The compressed hydrogen at ambient temperature is then transferred to the aircraft's onboard cryogenic hydrogen storage. This reduces boil-off and leakage compared to directly transferring cryogenic hydrogen.

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A system for jump-starting a hydrogen fuel cell in a hydrogen fuel cell-powered aircraft using the aircraft's electrical power system and energy storage devices, such as batteries or ultracapacitors. The system uses the electrical power stored in the energy storage devices to provide the initial high voltage required to start the fuel cell. A controller monitors the fuel cell's voltage and starts the fuel cell when it drops below a threshold. The controller then connects the energy storage devices to the fuel cell to provide the high voltage required for starting.

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Managing excess hydrogen fuel in fuel cell aircraft to prevent losses and reduce costs. The method involves offloading unused fuel from the aircraft's fuel tank to prevent boil-off or leaks. This is done when there is leftover fuel after a flight or if the flight is cancelled. The aircraft can be flown to a location needing power, like an airport during a natural disaster, and used to generate and provide electricity.

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Predictive fuel cell management for integrated hydrogen-electric systems like aircraft. It optimizes the number of fuel cells online at any given time to avoid wasting energy or damaging cells. The system uses a controller to monitor aircraft flight conditions and predict the power requirements for each phase of flight. Based on this data, it activates or deactivates fuel cells to match the power needs without overloading the fuel cell stack.

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A modular fuel cell system for aircraft propulsion that reduces size and complexity while improving efficiency. The system uses a compressor to supply air to multiple fuel cells through separate circuits instead of individual balance of plant systems for each cell. This allows a single compressor and cooling circuit to serve multiple cells, reducing weight and complexity compared to dedicated BOP systems for each cell. The system also has a controller that converts power from the first subset of cells into electrical current for an electric motor.

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A fuel cell powered UAV with a convertible cathode. The fuel cell can switch between using ambient air and using onboard stored oxygen. This allows the UAV to fly at higher altitudes where oxygen concentration is too low for normal fuel cells. The switchable cathode enables the fuel cell to adapt to changing oxygen availability during flight.

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Fuel cell system for aircraft that consumes hydrogen and oxidizer to eliminate venting flammable gases. The system uses a fuel cell along with a catalytic hydrogen burner to consume residual hydrogen and oxidizer gases. This prevents release into the aircraft cabin. The burner conditions the oxidizer before supplying it to the fuel cell. The reactions are exothermic and can be used to heat the fuel cell during startup or provide heat to other aircraft systems.

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A fuel cell powered aircraft that converts between using ambient air and stored oxygen to power the fuel cell, allowing operation above 15,000 feet where air oxygen is too low for normal fuel cells. The aircraft has a fuel cell cathode that can switch between air and oxygen, allowing it to use ambient air at lower altitudes, then switch to using stored oxygen at higher altitudes where air oxygen is insufficient. The switching can be automated based on flight parameters, atmospheric conditions, power demands, etc. This allows the aircraft to efficiently use ambient air when possible, while having the oxygen option for high altitude flight.

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An aircraft electrical power system using fuel cells for both auxiliary and primary power. The system has a fuel cell auxiliary power unit (APU) for auxiliary power and a fuel cell power plant for primary power. The APU and power plant share a hydrogen storage unit. This allows the aircraft to have a consistent fuel cell power source for both auxiliary and primary power needs. It eliminates the need for separate power generation systems and simplifies the aircraft's electrical architecture. The onboard hydrogen storage unit can be refueled externally using a ground-based hydrogen refueling unit.

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High-energy-density, fault-tolerant fuel cell system for clean-fuel electric vertical Takeoff and Landing (eVTOL) aircraft that provides reliable power for advanced air mobility vehicles. The system uses hydrogen fuel cells with onboard oxygen generation via turbochargers or superchargers to supply electrical power to the aircraft's motors and components. The fuel cell modules have heat exchangers to convert liquid hydrogen to gaseous hydrogen for the cells. This allows high-density liquid hydrogen storage and efficient onboard hydrogen generation. The fuel cell system is fault tolerant, lightweight, and uses air compression to regenerate oxygen instead of requiring additional oxygen tanks.

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Hybrid power system for unmanned aerial vehicles (UAVs) that combines fuel cells and lithium-ion batteries with chemical hydrogen storage. The chemical hydrogen storage is an alternative to high-pressure hydrogen tanks. It uses a container filled with ammonia borane, an absorbing material that releases hydrogen when heated. An electric heater inside the container is powered by the lithium-ion battery to start the hydrogen release. A valve controls the flow to the fuel cell stack. Sensors monitor temperature, pressure, and flow. This allows efficient hydrogen production without high-pressure tanks.

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A hydrogen fuel cell system for maximizing efficiency by using the vaporized hydrogen from a liquid hydrogen tank when it's not being driven. When the vehicle is stopped, a valve is closed on the liquid hydrogen line and another valve is opened to allow the naturally vaporized hydrogen to flow from the tank to the fuel cell stack. This captures the wasted vaporization loss and uses it to generate more electricity. The system also has features like a heat exchanger to optimize cooling efficiency.

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A modular fuel cell system for electric aircraft. The system uses hydrogen fuel cells to provide power for on-board electric motors. The fuel cells are housed in modular units that can be combined to scale up power as needed. The fuel cells receive compressed air and hydrogen, and produce electricity and water as byproducts. The cells are cooled using heat exchangers. The modular design allows fault tolerance and lightweight power generation for vertical takeoff and landing electric aircraft.

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A hydrogen fuel cell power system for drones that improves endurance and enables operation in harsh environments. The system uses a fuel cell powered by hydrogen stored in a tank. The fuel cell generates water vapor. A heat exchanger converts the water vapor to liquid water. This water is sent back to the fuel cell stack to humidify the reaction. This closed-loop water circulation reduces water loss compared to open-loop systems. It allows the drone to operate in arid environments without external water supply. A DC/DC converter regulates voltage between the fuel cell and lithium battery. This allows the battery to be smaller and lighter since it doesn't need to provide full power to the motor. The converter also ensures proper charging of the battery when the fuel cell is depleted.

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A hydrogen fuel cell power system for long endurance drones that addresses the challenges of water management and efficiency in hydrogen fuel cells. The system uses a hydrogen fuel cell module, hydrogen supply system, water electrolysis module, hydrogen circulation system, fuel cell stack controller, and electric motor. This integrated setup allows stable load management and prevents water imbalance issues that can degrade fuel cell performance and safety. It provides a safe and efficient power source for long endurance drones using hydrogen fuel cells.

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A fuel cell system for aviation using liquid hydrogen fuel that allows efficient thermal management of the fuel cell and enables variable operating conditions. The system uses the self-exothermic heat of the fuel cell to vaporize liquid hydrogen, and high-speed air flowing outside the aircraft as a cooling medium. This allows thermal coupling between the fuel cell and hydrogen vaporization. A water solenoid valve controls the hydrogen flow rate for variable operating conditions. The fuel cell's heat is dissipated by the circulating air.

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Low-pressure drop water exchanger for fuel cell power systems in unmanned air vehicles (e.g. drones) that allows longer flight times through efficient use of hydrogen fuel cells. The exchanger uses hollow tubes with water-permeable membranes to selectively transfer water vapor from the fuel cell exhaust to the intake. The membranes are made of materials like perfluorosulfonic acid or other polymers. The hollow tube design provides lightweight and low-pressure drop compared to existing water exchangers, making it suitable for airborne applications.

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Aircraft fuel cell system that is simpler, safer and more autonomous. It uses separate hydrogen zones, a hybrid pressure regulator, and allows independent power delivery without a converter.

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An engine system for aerospace vehicles that uses hydrogen produced by onboard water electrolysis instead of traditional fossil fuels. The system has a water electrolysis device, oxygen storage, hydrogen piping, and engine connected. A feedback device adjusts hydrogen production based on pipeline pressure. Valves purge excess hydrogen and oxygen. The engine is a piston engine with a hydrogen combustion process. This allows a fully self-contained hydrogen power system for aircraft that eliminates traditional fuel needs and emissions.

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A hybrid fuel cell power generator for unmanned aerial vehicles (UAVs) that enables long endurance flights. It combines a proton exchange membrane fuel cell with a hydrogen generator and recirculating hydrogen path. The generator has an ambient air path across the fuel cell cathode and a recirculating hydrogen path across the anode. Water is transferred from the cathode air to the hydrogen stream. A separate hydrogen generator adds hydrogen to the recirculating path. This closed loop system sustains fuel cell operation without external hydrogen tanks. Temperature control of components improves efficiency and longevity.

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An on-board electrical power system for aircraft that uses an integrated hydrogen generation and fuel cell system to provide backup power in case of primary power failures. The system generates hydrogen on board using a reaction between water and metal. This hydrogen is then used to power a fuel cell that provides electrical power to the aircraft's critical systems. The on-board hydrogen generation eliminates the need for external power sources like ram air turbines. It also allows real-time hydrogen production for instantaneous power. The system has advantages like smaller size, lighter weight, higher power density, better reliability, and reduced fuel consumption compared to external power sources.

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An aircraft emergency power system using a fuel cell instead of a ram air turbine to generate electrical power during emergency operations. It does this by supplying hydrogen gas and warmed air to a fuel cell system to generate power proportional to the demand. A solid hydrogen storage system releases hydrogen at a controlled rate matched to the fuel cell load.

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