Hydrogen Flow Optimization in Fuel Cells

Hydrogen storage and fuel delivery system for hydrogen-fueled engines in vehicles that allows longer driving range by optimizing fuel tank pressures. The system uses high-pressure (700 bar) hydrogen storage in the fuel tank. As fuel is consumed, the tank pressure decreases. Instead of maintaining a high minimum pressure in the tank, the system allows the pressure to drop lower. This reduces the amount of fuel that can't be used due to low pressure. By lowering the minimum pressure required for fuel delivery, more fuel can be stored and used from the tank before refueling. This compensates for the lower density of hydrogen gas compared to liquid fuels. It avoids wasting energy compressing or expanding the fuel pressure unnecessarily.

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A fuel cell-powered device like a drone that uses an onboard hydrogen generator instead of a separate hydrogen tank. The generator provides hydrogen to the anode of the fuel cell through a loop with a blower. The blower speed is controlled based on anode loop pressure to maintain optimal hydrogen flow. This allows a compact and lightweight fuel cell system with extended run times compared to lithium-ion batteries. The hydrogen generator replenishes hydrogen onboard, eliminating the need for external tanks. The blower speed adjusts to maintain optimal hydrogen flow based on loop pressure. This improves hydrogen utilization compared to fixed blower speeds. The controller also regulates fuel cell temperature and hydrogen generator temperature based on parameters like current, pressures, and temperatures.

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Introduction : The transport sector is still responsible for a large part (~8Gt/a) of worldwide carbon emission [1]. Polymer Electrolyte Membrane (PEM) Fuel Cells (FCs) are an important emission-free alternative application. Increased commercialization will lead to demand PEM-FCs. As the catalyst coated membrane (CCM) heart every FC, there need lean and cost-effective way produce CCMs. During CCM production inhomogeneities in layer can occur. Several groups worked on understanding impact such irregularities performance durability [2-6]. In this work we present results systematic experiment investigating missing CL (anode cathode) produced via screen printing under accelerated stress tests (ASTs). Microscopic elemental analysis reveal effects observed during electrochemical characterization. Production CLs CCMs house. Catalyst ink prepared target ionomer I/C ratio 0.8 with Pt/C 50 wt%/20 wt% cathode/anode respectively. printed glass fibre reinforced PTFE (Decal) substrate screen-printing. Screens designed that certain pre-defined geometries areas obtained (see attached image). Ten red... Read More

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Controlling the gas flow in a hydrogen tube trailer to ensure refueling capacity and power generation. The trailer has multiple hydrogen sources, a fuel cell, and a valve system. When the first source pressure drops below a threshold, it switches to the second source for refueling. But if the first source pressure is above the threshold, it uses it for fuel cell power generation. This allows continuous fuel cell operation and refueling without depleting sources. The trailer can also charge electric vehicles and balance between fuel cell and EV charging.

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Fuel cell system that can stably supply the required flow rate of fuel to the fuel cell stack even when the fuel demand increases. It uses an ejector to circulate unused fuel back to the supply passage. When the fuel demand exceeds a threshold, instead of immediately switching to a larger ejector nozzle, it continues using the smaller nozzle while also supplying extra fuel through a bypass passage. This allows keeping the higher efficiency smaller nozzle for longer, preventing a large decrease in ejector circulation efficiency.

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This study investigates the structure of a metal hydride (MH) cartridge as hydrogen storage tank for small-scale fuel cells (FCs). is designed to be stacked and used in layers, allowing flexible capacity adjustment according demand. MH enables compact safe cell (FC) applications due its high energy density low-pressure operation. However, because desorption from an endothermic reaction, external heat supply required stable performance. To enhance both transfer efficiency usability, we propose method that utilizes waste air-cooled proton-exchange membrane (PEMFC). The proposed incorporates four cylindrical tanks require uniform transfer. Therefore, arrangements within minimize non-uniformity distribution on surface. flow exhaust air PEMFC into was analyzed using computational fluid dynamics (CFD) simulations. In addition, empirical correlation Nusselt number developed estimate coefficient. As result, it concluded utilization rate flowing 13.2%.

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A system and process for efficiently converting liquid hydrogen to gaseous hydrogen for fuel applications while minimizing hydrogen losses. The system uses thermal compression to compress the hydrogen from liquid to high pressure without mechanical compressors. It involves transferring hydrogen between reservoirs at different pressures and temperatures to optimize compression efficiency. The steps include cooling liquid hydrogen, transferring it to a lower pressure reservoir, then heating it to compress it. This cycle can be repeated in multiple reservoirs to achieve multiple compression stages. By using the cold energy from higher pressure reservoirs to compress lower pressure ones, the process is more efficient than mechanical compressors.

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Enhancing energy efficiency is essential for proton exchange membrane fuel cells (PEMFCs) operating in a dead-ended anode (DEA) mode. This study proposes the integration of buffer tank, positioned between mass flow meter and cell, to reduce hydrogen loss during purge events. The tank stores when valve closed releases it opens, thereby stabilizing pressure, minimizing waste, improving overall system efficiency. effectiveness experimentally evaluated under varying load currents, supply pressures, intervals, durations. objective determine optimal duration that maximizes efficiency, both with without tank. results show consistently improves Under conditions (0.1 bar, 8 A, 0.1 s duration, 20 interval), increases by 3.3%. non-optimal 1 improvement reaches 71.9%, demonstrating tanks performance across wide range conditions.

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Fuel cell system with electrochemical fuel recovery that extracts unused fuel from the exhaust to improve overall fuel utilization efficiency. The system has a fuel cell stack, an electrochemical pump separator containing an anode, cathode, and electrolyte, a fuel exhaust line connecting to the anode, and a product line connecting to the cathode. The exhaust fuel is pumped back to the fuel inlet using the electrochemical pump separator. This recovers unused fuel from the exhaust and sends it back for reuse in the stack, improving overall fuel utilization compared to just venting the exhaust.

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Separator design for electrochemical devices like fuel cells and batteries that improves performance by providing optimized flow paths for fluid flow. The separator has streamlined walls with non-parallel end segments that connect the inlet and outlet. This shape reduces pressure drop, improves flow efficiency, and provides a large contact area between the fluid and the separator walls. The streamlined walls alternate between protrusions in a direction perpendicular to the flow direction.

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A nozzle assembly for combustion chambers of engines, like hydrogen fuel cell engines, with a unique design to optimize fuel injection and mixing. The nozzle has a central fuel pipe that seals against air ingress. Fuel flows into the pipe through a reservoir and multiple openings. This allows even distribution of fuel into the pipe. The pipe has a flow body to improve fuel flow homogeneity. Radially offset air-guiding ducts create an air flow around the fuel at the nozzle exit, drawing it outward and forming a recirculation zone for fuel-air mixing.

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Hydrogen generation system with improved efficiency by bypassing a portion of the air flow to the stack and using it to cool the hydrogen product instead. This allows reducing the air flow through the recuperator and heater, lowering their power requirements. The bypassed air cools the product stream without overheating it, preventing damage to the hydrogen processor. The remaining air still goes through the recuperator and heater to supply oxygen for the stack.

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Cryostorage system for hydrogen fuel cells that allows filling and extraction from the inner tank without external equipment like blowers. The system has a cryocontainer with an inner tank and outer container. A cryopump inside the inner tank extracts liquid/gaseous hydrogen for the fuel cell at higher pressure. Filling is via an interface that bypasses the pump. It uses a valve in the fill line to divert filling into the inner tank or through the pump. This allows filling via the pump's extract line without pumping. A shuttle valve switches between pump and fill line access. A return line from the fuel cell pumps hydrogen back into the inner tank. This maintains inner tank pressure for future fillings.

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Mobility with hydrogen fuel cells that limits power during refueling to prevent pressure drops that could restrict hydrogen flow to the fuel cell. When entering refueling mode, the storage vessel pressure is lowered to prevent hydrogen supply pressure from dropping below the fuel cell's needs. If the hydrogen pressure is below the target during refueling, power is limited. This prevents pressure drops from vaporizing hydrogen and reducing refueling capacity. The user is notified of power limits to understand why.

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Fuel cell stack design with parallel feed gas flow for improved performance and stack compression. The fuel cell stack has fuel cells where the anode or cathode has an extended edge seal chamber that receives and outputs the feed gas in a direction parallel to the other gas flow. This allows the anode and cathode feed gases to flow parallel through the stack instead of perpendular. This provides a one-dimensional current distribution and temperature gradient, avoiding hot corners and stack distortion.

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Controlling a fuel cell system with a mixed gas fuel tank to accurately estimate the hydrogen composition of the mixed gas for optimal fuel cell operation. The method involves estimating the hydrogen composition by solving simultaneous equations with unknowns like fuel flow rate and air flow rates to the combustor. Equations represent relationships between air flow, exhaust gas oxygen and temperature. This allows calculating hydrogen composition without knowing it initially. The estimated hydrogen composition is then used to set the fuel cell fuel flow rate.

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Fuel cell separator design to prevent gasket burrs and improve gas flow for better performance. The separator has a reaction region with manifolds around it, one of which is for reaction gas intake. Holes connect the intake manifold to the reaction region. An inlet flow field plate replaces the traditional gasket support. This prevents blockages while maintaining pressure. The plate forms a smooth gas flow path between the holes and reaction region.

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Hydrogen purification system with improved efficiency by periodically increasing and decreasing the pressure of the anode in the hydrogen purification module. This removes trapped gases and moisture from the anode flow path to improve hydrogen purification. A pressure control unit connects to the anode outlet and a control unit opens/closes it. Increasing anode pressure >0.04 bar helps hydrogen diffusion and decreasing removes trapped gases.

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A hydrogen supply system for fuel cells that allows reusing excess hydrogen gas that wasn't consumed in the fuel cell, preventing wasteful release into the atmosphere. The system has multiple hydrogen tanks connected to the fuel cell via supply paths. Some tanks are reserve tanks connected to the supply paths via recovery paths. When the fuel cell doesn't use all the hydrogen, the excess goes to the reserves instead of venting. This allows reusing unused hydrogen from the reserves later.

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Abstract This study investigates the thermal behavior of polymer electrolyte membrane (PEM) fuel cells using hydrogen and methanol fuels. An extensive 3D model was constructed for simulation temperature, current density, efficiency distribution, with Nafion EW1100 membranes under high-temperature conditions COMSOL Multiphysics. Moreover, this highlights essential connection between temperature profiles performance entire cell. However, at a given voltage 0.4 V 0.8 V, consistently operated lower temperatures Gas Diffusion Layer (GDL), Electrode (GDE), PEM compared to fuel. For instance, 4-5 K than that hydrogen, difference increased 4-6 K. The differential is indicative hydrogen's ability manipulate its heat-generating dissipating processes more efficiently PET. demonstrates hydrogens advantages over other because density correlates temperature. all temperatures, provides higher densities hydrogen-methanol, supporting usefulness in improving cell efficiency. management not only improves but also prolongs PEM, GDL, GDE life by decreasing stress. Hence, from analysis, it shown contri... Read More

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The effect of electrolyte binders (ionomers) in the anode catalyst layer (ACL) on chemical degradation rate polymer membranes (PEMs) fuel cells was examined a single cell with an accelerated stress test (AST) at 90 C, while H 2 O formation rates, j (H ), and activities for hydrogen oxidation reaction (HOR) ionomer-covered Pt/C catalysts were measured half 0.1 M HClO 4 solution 80 C. A sulfonated polyphenylene (SPP-QP) conventional Nafion used as ionomer PEM. It demonstrated that PEM decreased remarkably use SPP-QP together lower Pt-loading carbon support. suppression via specific adsorption Pt its low permeability contributed to longer lifetime AST.

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Minimizing fuel cell stack degradation and efficiently satisfying the required output of the stack by employing an air recirculation valve and a hydrogen recirculation pump. The fuel cell system has separate air and hydrogen supply lines. It recirculates some of the air and hydrogen from the cathode and anode back into the stack. The recirculation flow rates are controlled based on stack output voltage and current. This helps balance cell pressures and prevent voltage/current imbalances that cause stack degradation when output is low.

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A fuel cell flushing system and method to remove nitrogen from the fuel cell stack without restarting the fuel cell. The system uses the fuel supply valve and hydrogen line purge valve to change hydrogen flow velocity. First, adjust hydrogen pressure in the supply line. Then, open supply valve and cut off purge valve to increase flow. This flushes nitrogen from the cell without restarting.

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Hydrogen fuel cell system with improved performance and reliability through pulsed jet recirculation and pulse width modulated (PWM) injectors. The system reduces hydrogen pressure from high to medium using pulsed injectors instead of mechanical pressure reducers. This provides better control, stability, and controllability. The pulsed injectors have discrete open and closed states. PWM control allows adjusting recirculation rate by pulse width. This pulsed recirculation improves efficiency and stability compared to continuous recirculation. The pulsed injectors also have lower stress and longer life than continuous valves.

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Improving hydrogen utilization in fuel cell systems by decoupling the pressure and hydrogen flow control of the anode purge valves. The method involves determining compensation values for adjusting the proportional valve opening and tail exhaust valve closing to compensate for the influence of one variable on the other. By using these compensated values instead of the original openings, stable anode pressure can be achieved while mitigating hydrogen waste during purge cycles. This allows single variable control of both pressure and utilization instead of the coupled multi-variable control.

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Fuel cell hydrogen circulation system and control method that improves hydrogen utilization and efficiency at both low and high power levels. The system has parallel loops with a hydrogen circulation pump for low power and an ejector for high power. Switch valves allow selecting the pump or ejector based on fuel cell output. At low power, the pump recirculates hydrogen. At high power, the ejector injects hydrogen into the cell outlet for reuse. This avoids pumping energy waste while still providing sufficient hydrogen flow for high power.

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Fuel cell nitrogen purging system and control method to improve fuel cell startup performance by optimizing nitrogen purging after shutdown. The system uses a hydrogen recirculation loop and a variable bypass flow to purge nitrogen from the hydrogen storage tank. A sensor measures the recirculated hydrogen concentration. The bypass flow is increased if the hydrogen concentration is too low, allowing faster purging. If the concentration is too high, the bypass flow is decreased to save power. This adaptive purge strategy prevents excessive hydrogen waste and concentration extremes.

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Method for supplying an anode of a fuel cell stack through an anode supply of a fuel cell unit that enables expanding the operating range of the fuel cell stack at low loads. The method involves operating at least one hydrogen metering valve in the anode supply path in a pulsed (clocked) manner in a specific operating range of the fuel cell stack. This allows supplying the anode with hydrogen in a pulsed manner at low loads instead of continuously. It prevents excessive differential pressures in the anode at high loads while enabling operation at lower loads where continuous supply is not required.

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Hydrogen supply system for fuel cell vehicles that provides precise hydrogen flow control to enable stable fuel cell performance under varying load conditions. The system has a primary hydrogen supply branch with fixed flow rate and a secondary branch with adjustable flow. A valve controls the secondary branch flow. By using both branches, hydrogen supply can be tailored to meet demand. This prevents under/over supply issues with a fixed branch when load changes. The secondary branch also allows increasing hydrogen flow for high power loads. A feedback flow meter adjusts the valve for precise hydrogen flow.

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Fuel cell stack anode water management and control system that prevents flooding and drying issues in fuel cells to improve performance and reliability. The system uses solenoid valves to selectively open and close the anode hydrogen inlet and outlet ports. This allows controlling the hydrogen flow direction and volume to balance water distribution inside the stack. By monitoring stack internal resistance, the valves are automatically switched to prevent flooding and drying.

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Fuel cell system with selective hydrogen discharge to improve stability and durability. The system has two hydrogen discharge lines from the fuel cell stack: one connects to the air discharge line upstream of the pressure adjuster, the other connects to the air discharge line downstream. A valve on each line opens/closes based on anode pressure. This allows flexible hydrogen discharge without pressure fluctuations. It prevents corrosion from cathode hydrogen and stabilizes output vs. discharge flowrate.

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A fuel cell hydrogen supply system that enables reliable operation of fuel cell systems in applications like power generation. The system has a dedicated hydrogen supply unit connected to the fuel cell stack. It uses a control strategy with separate basic and feedback compensation duty settings for the hydrogen supply valve. The basic duty is set based on stack status, and feedback compensation adjusts based on stack performance. This allows optimized hydrogen supply to prevent stack voltage imbalances and durability issues.

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Hydrogen common rail control system for fuel cells that improves hydrogen flow accuracy and reduces heat generation in fuel cells by using an ejector and pump in parallel, closed-loop control of proportional valves, and a switch valve. The system has two proportional valves, one main valve and one bypass valve, that are controlled based on pressure feedback to ensure consistent outlet pressures. This reduces variations in hydrogen flow due to valve consistency issues. An ejector and pump are used instead of a single pump to provide backup flow. The switch valve opens after a certain time to reduce heat generation by allowing some hydrogen to bypass the fuel cell during startup.

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Fuel cell hydrogen circuit pressure control method to improve stability of hydrogen pressure for fuel cell systems. The method involves staggering the opening times of the hydrogen discharge valve and the drain valve when both are opened at the same time. This prevents sudden pressure drops by allowing the hydrogen discharge to finish before draining starts. The staggered opening times keep the hydrogen cycle and duration unchanged.

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A hydrogen fuel cell system with exhaust and drainage control to improve hydrogen utilization and stability. The system has sensors to monitor hydrogen concentration and water level in the hydrogen circuit. Exhaust and drain valves are added to the separator at the circuit outlet. The valves are controlled based on sensor feedback to intermittently exhaust and drain nitrogen and water. This avoids excessive accumulation while maintaining stable fuel cell operation.

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Hydrogen fuel cell system with dynamic hydrogen consumption adjustment to avoid waste and reduce operating costs. The system has a hydrogen supply subsystem, a hydrogen buffer subsystem, a fuel cell subsystem, and a control subsystem. The buffer subsystem contains a booster pump, tank, and valve. The control subsystem adjusts pump pressure, valve opening, and fuel cell hydrogen production rate based on fuel cell power and tank pressure changes. This allows dynamic hydrogen consumption matching to prevent waste compared to fixed supply.

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Fuel cell hydrogen supply and circulation system with active control of temperature and humidity parameters to optimize hydrogen management in fuel cells. The system has a hydrogen circulation loop with heat exchangers, separation drainer, and pump to condense and separate moisture from the hydrogen. Sensors monitor stack inlet and outlet gas conditions. An electronic control unit uses this data to actively adjust the hydrogen source temperature, anode entry temperature, and flow ratios to match stack requirements. This allows proactive moisture and humidity management during load changes to prevent condensation, flooding, and pump damage.

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Hydrogen supply system for fuel cell vehicles that provides optimized hydrogen flow and pressure for fuel cell stack operation over the full power range. It uses an adjustable proportional valve between the air intake and hydrogen injector to dynamically vary the hydrogen pressure based on the fuel cell's operating point. This prevents overshoot and underflow issues that can occur with fixed hydrogen injector sizes at low power. A control method adjusts the proportional valve in real-time based on the fuel cell's operating point to maintain optimal hydrogen flow and pressure.

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Fuel cell stack hydrogen control system with dual proportional valves for precise and efficient hydrogen supply to the fuel cell stack over the full power range. The system uses two proportional valves with different diameters connected in parallel. A controller adjusts the opening of each valve based on stack power and hydrogen pressure. This allows optimized hydrogen flow and pressure control using smaller diameter valves at low power, while avoiding high pressure fluctuations and valve wear at high power.

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Fuel cell hydrogen supply system with improved efficiency and adaptability over a wider power range compared to traditional systems. The system uses parallel ejectors with valves to recirculate excess hydrogen back into the fuel cell. The parallel configuration allows higher ejector ratios and thus better recirculation at lower power levels compared to a single ejector. This improves efficiency by reducing waste hydrogen and simplifies system design compared to a compressor. The valves enable fine tuning of the recirculation flow.

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Hydrogen pressure stabilization device for hydrogen fuel cells to prevent excessive hydrogen pressure from damaging the fuel cell stack. The device uses a manually operated valve with a visual indication when the hydrogen pressure is too high. If the pressure in the delivery pipe rises, the valve stem lifts out of the valve seat. This visible lift indicates high pressure. The operator can then adjust the source valve until the stem falls back. This prevents excessive hydrogen from entering the stack. A relief valve in the delivery pipe allows excess pressure to vent. After pressure normalizes, the main valve can be opened again.

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Hydrogen circulation system for fuel cell power systems that improves efficiency, reduces power consumption, and simplifies design compared to conventional pumps. The system uses an ejector instead of a pump to recirculate unreacted hydrogen from the fuel cell stack. A valve controls hydrogen return based on power level. This improves hydrogen utilization, eliminates pump power consumption, and reduces system size/weight.

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Fuel cell anode pressure control method and system that improves the dynamic response of fuel cell stack pressure during rapid load reductions. It uses a split-range control strategy with a hydrogen exhaust valve in addition to the regular pressure regulating valve. This allows more flexible and rapid anode pressure adjustment compared to just the regulating valve. The exhaust valve assists with pressure reduction when the regular valve is fully closed during rapid load reductions. It avoids the issue of slow response due to hydrogen consumption alone.

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A mechanical hydrogen supply system and method for prolonging the life of fuel cell stacks by preventing oxygen ingress and catalyst degradation when the fuel cell system is shut down. The system uses a hydrogen circulation pump, fuel cell stack hydrogen chamber, and water separation module connected in a loop. When the fuel cell system is shut down, the pump circulates hydrogen from the stack chamber through the water separation module to remove any oxygen. This maintains a reducing atmosphere in the stack chambers to prevent catalyst oxidation. The method involves starting the pump after shutdown to circulate hydrogen and separate oxygen.

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Fuel cell engine hydrogen supply system control method to improve reliability and efficiency. The method involves dynamically adjusting the hydrogen inlet pressure based on engine current, separator status, and inlet temperature. It uses a temperature sensor at the stack inlet to determine a secondary compensation value for the pressure regulating valve. This accounts for cold temperatures that can reduce hydrogen density. The primary compensation based on engine load and separator status is also used. The compensated valve opening is then dynamically adjusted using PID control to optimize the hydrogen inlet pressure. This reduces pressure imbalance across the membrane, prolonging membrane life.

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Controlling a fuel cell to purge only small amounts of hydrogen in real time, even when the cell isn't generating much power. The method involves adjusting the opening degree of a fuel cell hydrogen purge valve based on the accumulated cell current. This allows purging a proportional amount of hydrogen as the cell output decreases. It prevents excessive hydrogen buildup in the cell when it's not fully loaded. By using a duty cycle PWM signal to control the valve, tiny purges can be done in low flow rate situations.

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A fuel cell system that allows independent and controllable hydrogen supply to the fuel cell stack. The system has components like an air compressor, injectors, valves, sensors, and exhaust valve that allow precise adjustment of hydrogen pressure and volume in the stack fuel chamber. This eliminates the need for external hydrogen tanks and reduces calculations and adjustments compared to conventional systems. The system uses sensors to monitor stack conditions and valves to adjust hydrogen delivery. An exhaust valve relieves overpressure or purges anode gas as needed.

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Electronically controlled hydrogen supply device for fuel cell systems that extends the duration of the hydrogen-reduced atmosphere inside the fuel cell stack to slow down stack degradation when the system is shut down. The device has a hydrogen pump, valves, and modules connected in a loop to circulate and purify the hydrogen. Electronic control systems open and close the valves to manage the hydrogen flow and pressure. This maintains a hydrogen-rich atmosphere in the stack chambers to prevent oxygen ingress and catalyst oxidation when the system is idle.

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Fuel cell system using a low-pressure hydrogen source to address issues with high-pressure hydrogen bottles. The system has a hydrogen pump, air pump, water pump, radiator, hydrogen intake valve group, splitter water heater, throttle valve, and one-way valve. The air pump draws air from atmosphere, the hydrogen pump supplies hydrogen, and the water pump circulates coolant. The hydrogen and air enter the fuel cell stack. The coolant circulates between stack, radiator, and pump. The throttle valve regulates stack outlet pressure. The splitter water heater separates water from the coolant. This allows operating the fuel cell with low-pressure hydrogen and air, avoiding high-pressure bottles. The water pump recirculates coolant.

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Hydrogen supply system and control method for fuel cells to improve hydrogen supply reliability while minimizing output degradation. The method involves estimating the maximum hydrogen line pressure when supply matches consumption, detecting supply failures based on pressure deviation, and limiting current when failures occur. This allows continued operation with reduced hydrogen flow while maintaining cell output. It also increases hydrogen line pressure to mitigate failures.

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