Hydrogen Flow Optimization in Fuel Cells

Hydrogen engine fuel system with a compressor/expander to use more of the stored fuel and reduce pressure-regulation losses. Installed between the tank and injectors, the unit expands hydrogen when tank pressure exceeds the required injection pressure and compresses it when tank pressure falls below that level. It operates directly on gaseous hydrogen without adding liquid. A controller uses pressure and temperature readings at the tank outlet to adjust inlet and outlet valve timing, metering hydrogen through the unit to maintain the required delivery pressure.

Source

Fuel cell power generator that regulates hydrogen supply pressure by adjusting a recirculation blower’s speed. Hydrogen flows from a hydrogen generator through the blower to the fuel cell’s anode, then returns to the generator through a water exchanger that adds water to the returning gas. A controller measures pressure in this loop and adjusts blower speed against pressure thresholds to control delivery to the anode. The fuel cell’s electrical output can charge a connected battery.

Source

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

Source

Hydrogen tube trailer that uses lower-pressure hydrogen to generate electricity onboard while reserving higher-pressure hydrogen for vehicle refueling. Multiple hydrogen storage banks connect to both a refueling outlet and an onboard fuel cell through valve-controlled piping. When a bank’s pressure falls below a dispensing threshold, the controller feeds its hydrogen to the fuel cell while another bank can continue refueling vehicles. The fuel cell powers trailer equipment or external loads, including electric vehicle chargers. Adjusting the threshold changes how much hydrogen is reserved for electricity generation versus refueling.

Source

Fuel cell system with an ejector bypass to prevent fuel shortages when changing nozzle sizes. At low demand, a small ejector nozzle supplies fresh fuel and draws unused fuel back from the stack. When demand outgrows this nozzle, a flow-controlled bypass supplies the extra fuel directly to the stack while the small nozzle keeps recirculating unused fuel efficiently. The system switches to a larger nozzle only when demand reaches the range where that nozzle’s recirculation efficiency peaks, avoiding the drop in recirculated fuel caused by switching too early.

Source

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%.

Source

Liquid hydrogen boil-off recovery system that uses the cold of outgoing liquid hydrogen to help compress gas that would otherwise be lost. Liquid withdrawn from the storage tank flows through a main circuit and supplies cooling to a thermal compressor in a separate boil-off recovery circuit. The compressor raises the recovered gas pressure through cooling and heating, acting either directly on the gas or through an intermediate material such as a metal hydride. This couples boil-off recovery with normal liquid withdrawal to reduce compression energy consumption.

Source

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.

Source

Fuel cell system that recycles hydrogen from spent fuel while using exhaust heat to preheat incoming air. Part of the fuel exhaust passes through an air preheater and then an electrochemical separator that returns recovered hydrogen to the fuel inlet. Two water-gas shift catalysts increase the hydrogen available for recovery: one coats the preheater’s exhaust conduit, and the other is connected to or integrated with the separator. The remaining fuel exhaust bypasses recovery and enters a tail gas oxidizer, where it burns with the separator’s residual fuel and the stack’s cathode exhaust.

Source

Fuel-cell and electrolyzer separator designed to improve performance by shaping fluid flow with streamlined walls set at different angles. The walls form passages connecting the fluid inlet and outlet. An upstream wall and a downstream wall have different overall orientations, measured by the lines joining each wall’s ends. Individual walls may also have two connected streamlined sections with lateral bulges along an axis running from inlet to outlet.

Source

Hydrogen fuel nozzle for engine combustion chambers that moves fuel-air mixing outside the nozzle rather than forming a combustible mixture inside it. Fuel travels from a supply line in the nozzle holder through a central pipe sealed against air entry, then exits at the nozzle tip. An optional feed reservoir distributes fuel around the pipe through openings sized to equalize their flow rates. Separate surrounding air ducts can supply swirling air to mix with the discharged fuel and stabilize combustion downstream.

Source

Solid oxide electrolyzer with an air bypass to reduce heater power without compromising hydrogen cooling. Incoming air first cools the hydrogen leaving the electrolyzer, then splits: one portion is heated and fed to the cell stack, while the rest bypasses the air recuperator, heater and stack. This keeps enough airflow through the hydrogen cooler to protect downstream processing equipment, while reducing the air volume that must be heated for electrolysis.

Source

Hydrogen cryostorage system that delivers fuel at high pressure while keeping the storage tank at lower pressure to retain more hydrogen and delay boil-off. A linear cryopump inside the tank pumps liquid or gaseous hydrogen through a shared extraction and filling line. During refilling, a branch from this line routes hydrogen around the pump through a spring-loaded check valve inside the tank. The pump delivers from both sides, with a nearby check valve allowing selection between liquid and gas delivery.

Source

Liquid-hydrogen vehicle that prepares for refueling by lowering tank pressure, allowing more hydrogen to be added at the next fill. Because lower tank pressure can restrict hydrogen flow to the powertrain, the controller reduces power output when the measured supply pressure falls below a threshold set according to the tank’s target operating pressure. This lets the vehicle operate with reduced fuel demand while preparing for refueling. Preparation can start when a hydrogen station is selected as the destination or a dedicated switch is activated, and can require the driver’s consent.

Source

Fuel cell with a projecting gas-routing chamber that makes anode and cathode gases flow in parallel, reducing uneven heating and distortion in stacked cells. The gases enter from perpendicular sides, but the chamber turns the anode gas before it reaches the active area, aligning its flow with the cathode gas. This chamber extends outside the anode and overhangs the cathode inlet. Parallel flow replaces corner-to-corner temperature differences with a mainly one-directional temperature gradient, helping cells remain flat and maintain uniform contact and compression.

Source

Fuel cell controller that compensates for changing fuel-gas composition so hydrogen production matches the required electrical output. It uses the startup combustor, which heats air entering the fuel cell, to estimate the gas mixture rather than relying on its carbon content. The controller varies combustion air flow and uses exhaust oxygen concentration, temperature, or both to solve balance equations for the component proportions and unknown combustor fuel flow. A further equation requires the component proportions to sum to one. The resulting composition estimate determines the fuel flow supplied to the fuel cell.

Source

Fuel cell separator that replaces gasket supports with a flow-field plate to avoid molding burrs that restrict gas flow and water drainage. Gas from an inlet manifold travels along the cooling side, passes through holes to the reaction side, and flows toward the central reaction region. The plate sits on the reaction side between these holes and the reaction region, supporting the separator against deformation while providing a straight gas flow path. Removing the gasket supports between inlet holes eliminates a source of burrs without sacrificing contact pressure.

Source

Hydrogen purifier that clears trapped gas and water vapor from its anode flow path by rapidly raising and lowering anode pressure. The purifier extracts hydrogen from a mixed gas using electrically powered membrane-electrode assemblies. A controller briefly restricts the anode exhaust flow to raise pressure by at least 0.04 bar, then restores the original flow to bring pressure back down. This clearing cycle improves purification efficiency and can run periodically or be triggered by low current or high cell voltage.

Source

Hydrogen fuel-cell tractor that recovers excess hydrogen released from heated storage tanks when power demand falls, avoiding fuel waste and atmospheric venting. A recovery line directs gas not consumed by the fuel cell into a reserve tank for later reuse. The tractor uses multiple hydrogen tanks connected in parallel, with the fuel cell and battery housed under the front hood. The operator’s step sits between the fuel cell system and traction motor, below the seat; a PTO shaft behind the motor delivers power to working equipment.

Source

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

Source

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.

Source

Fuel cell system that recirculates air and hydrogen to prevent uneven gas supply from degrading the stack at low power demand. Separate loops return air from the cathode outlet and hydrogen from the anode outlet to their respective inlets, with a valve controlling air recirculation and a pump pressurizing returned hydrogen. A controller adjusts either recirculation flow based on required stack power and output voltage or current, improving gas distribution between cells without relying solely on fresh gas supply.

Source

Fuel cell nitrogen flushing system that clears the anode before restarting, avoiding repeated failed starts and wasted hydrogen. With the purge valve closed, the controller opens the hydrogen supply valve to build pressure in the supply line. It then coordinates changes in the supply valve opening with opening and closing of the purge valve, varying hydrogen flow velocity to flush nitrogen from the stack.

Source

Hydrogen fuel cell system using separately controlled injectors to regulate hydrogen supply and exhaust-gas recirculation across changing tank pressures and loads. An on/off injector replaces the mechanical pressure reducer, feeding hydrogen at intermediate pressure to a second injector upstream of an ejector nozzle. The ejector draws in anode exhaust gas and mixes it with fresh hydrogen for reuse. Independently adjusting intermediate pressure and the second injector’s opening pulses controls recirculation; higher pressure with shorter openings increases recirculation. Multiple pressure-reduction injectors can be activated as tank pressure falls to maintain hydrogen delivery.

Source

Fuel cell hydrogen circulation controller that stabilizes anode pressure while limiting hydrogen wasted when purging nitrogen and water. It coordinates the hydrogen supply valve and purge valve rather than controlling them independently. By varying their openings within preset ranges and measuring anode inlet pressure and hydrogen flow, it determines their coupled effects. The supply valve is then adjusted to counter pressure disturbances from purging, while the purge valve is adjusted to account for the supply valve’s effect on hydrogen utilization.

Source

Fuel cell hydrogen recycling system that combines a circulation pump and an ejector to reuse unconsumed hydrogen instead of relying on either device alone. Hydrogen returns to the cell through two parallel paths, one containing the pump and the other the ejector, each with a downstream shutoff valve. A shared fresh-hydrogen supply feeds both paths: directly into the ejector and into the pump path between the pump and its valve.

Source

Fuel cell startup purge system that removes accumulated nitrogen without wasting hydrogen or damaging the membrane through excessive pressure differences. Hydrogen sensors in the recirculation loop and mixed exhaust let a controller track hydrogen recovery and exhaust dilution. Using these readings, ambient pressure and a lookup table, the controller adjusts the hydrogen purge valve, cathode outlet throttle and compressor bypass valve rather than relying on fixed purge settings. The bypass sends air directly into the exhaust to dilute discharged hydrogen while limiting compressor power use.

Source

Fuel cell hydrogen supply that uses pulsed metering to keep the stack operating at low loads where continuous hydrogen delivery is unsuitable. The controller opens and closes a hydrogen metering valve rather than metering continuously, extending the stack’s operating range to smaller average hydrogen flows. In systems with a jet pump, the supplied hydrogen also draws anode exhaust gas back into the stack. At higher loads, the valve can return to continuous metering to avoid excessive pressure peaks caused by pulsing.

Source

Fuel-cell hydrogen supply system that supplements a fixed-flow supply with an adjustable parallel branch to meet changing power demand more quickly. The fixed-flow branch supplies a baseline amount of hydrogen, while a valve in the adjustable branch meters the remaining amount needed. A hydrogen controller selects which branches operate based on load demand and uses measured flow to refine valve opening. A separate power controller compares actual output with demanded power and requests further hydrogen-flow adjustments through the adjustable branch.

Source

Fuel cell stack with switchable hydrogen feed direction to balance anode moisture and reduce drying at one end and flooding at the other. Stack resistance and voltage measurements guide a controller that switches three solenoid valves. Hydrogen normally enters one end and vents from the other. To redistribute moisture, the controller closes the vent and supplies hydrogen through that same port, briefly feeding both ends before shutting the original inlet after 0.3–1 second. This changes the hydrogen feed direction without a hydrogen circulation pump or ejector.

Source

Fuel cell hydrogen purge system that switches discharge paths according to anode pressure to avoid destabilizing stack pressure and power output. Hydrogen enters the cathode exhaust through two connections, one before and one after the exhaust pressure-control valve. Valves with different opening-pressure thresholds select which paths carry hydrogen, allowing discharge against different backpressures rather than relying solely on either connection. Pressure-actuated check valves can provide this switching without separate valve-control logic.

Source

Hydrogen supply system for stationary fuel cells that maintains power generation without an anode-inlet pressure sensor, avoiding shutdowns to replace deteriorated sensors. Instead of regulating hydrogen pressure directly, the controller selects a supply-valve duty cycle from a current-demand map and adds a feedback correction to keep stack output at its target. When the purge valve opens, the correction compensates for discharged gas. Baseline valve settings differ for startup, generation, and shutdown, and can be scaled according to anode or coolant temperature.

Source

Fuel-cell hydrogen supply system with separate pressure-feedback control of its main and bypass valves to maintain their target outlet pressures. Fresh hydrogen flows through a proportional valve into an ejector, or through a second proportional valve that bypasses the ejector and feeds the same outlet. A pressure sensor downstream of each valve lets a controller adjust that valve’s opening to match its pressure setpoint. Returning hydrogen is recirculated through the ejector or a hydrogen circulation pump connected in parallel with it.

Source

Fuel cell hydrogen pressure control that prevents the purge and water drain valves from opening together, avoiding large pressure drops that destabilize stack output. Purge and drainage intervals and/or opening durations are set according to power demand. When either valve receives an opening command while the other is open, the controller holds it closed so their openings are staggered. The timing shift preserves the specified intervals and/or opening durations while preventing the combined gas loss from simultaneous purging and drainage.

Source

Hydrogen fuel cell recirculation system that removes accumulated nitrogen and water as needed, avoiding hydrogen waste from fixed-interval purging. Unused hydrogen leaving the stack passes through a gas-water separator before being pumped back to the stack inlet. A hydrogen concentration sensor and a liquid level sensor in the separator independently control an exhaust valve and a bottom drain valve, triggering gas purging or water drainage based on measured conditions. During discharge, the circulation pump speed and hydrogen supply valve opening are adjusted to keep pressure stable.

Source

Hydrogen fuel cell system that adjusts hydrogen supply to changing electrical output rather than feeding hydrogen at a fixed rate, reducing waste and operating costs. A booster pump fills a buffer tank, which feeds a solid oxide fuel cell through a control valve. The controller uses fuel-cell output and tank pressure to adjust the valve opening, pump pressure and hydrogen production rate, coordinating delivery from the tank with its replenishment. An optional heat-recovery loop transfers heat from the fuel-cell exhaust to the hydrogen supply subsystem.

Source

Fuel cell hydrogen recirculation system that adjusts hydrogen temperature and humidity to prevent water accumulation as operating loads change. A heat exchanger transfers heat from moist anode exhaust to incoming fresh hydrogen, followed by a separator that removes condensed water before the exhaust reaches the circulation pump. Separately controlled heaters supplied by heated stack coolant warm the dried recirculated gas and fresh hydrogen before they mix and enter the stack. A bypass around the initial heat exchanger provides another adjustment, allowing coordinated gas-temperature control and independent control of anode-inlet relative humidity.

Source

Fuel-cell hydrogen injector with an upstream proportional valve to prevent excessive hydrogen delivery at low power without sacrificing high-power flow capacity. Rather than relying only on injector switching, the device varies the pressure feeding the injector. A controller monitors fuel-cell current or operating point, looks up the required inlet pressure, and adjusts the proportional valve opening to match. This allows a large-flow injector to serve both low- and high-power operation with less pressure overshoot. The two valves can share an integrated housing.

Source

Fuel cell hydrogen supply with two differently sized proportional valves to avoid unstable pressure control when a high-power stack runs at low power. The valves connect in parallel: the smaller valve handles low flow, and the larger valve opens as demand exceeds the smaller valve’s capacity. A controller compares measured stack-inlet pressure with the target pressure, calculates a combined opening command, and divides it into duty-cycle commands for the two valves. This arrangement provides fine control at low demand without sacrificing the flow capacity needed at high power.

Source

Fuel cell hydrogen supply system using two parallel ejectors to recycle unused hydrogen across a wider power range than a single ejector can efficiently cover. Each ejector draws returning hydrogen into the fresh hydrogen stream, with a separate proportional valve regulating its fresh hydrogen supply and a check valve preventing reverse flow through its return inlet. A third, independently metered parallel path supplies hydrogen without passing through either ejector, providing additional flexibility in meeting the stack’s hydrogen demand.

Source

Hydrogen fuel-cell pressure stabilizer that detects excessive supply pressure upstream of a shutoff valve to protect the stack. A sensor mounted inside the hydrogen line controls the valve, stopping hydrogen flow when pressure is too high. The assembly includes a vertically movable valve stem with a gas-flow clearance around its seat and a retaining ring that limits stem travel. An optional relief valve vents excess pressure so the shutoff valve can be manually reopened once pressure returns to normal.

Source

Fuel-cell hydrogen recirculation system that replaces the circulation pump with an ejector to reduce auxiliary power consumption, size and weight. Incoming pressurized hydrogen powers the ejector, drawing unused hydrogen from the stack exhaust back into the stack. Recirculation operates only above a selected power threshold of 40–80% of rated output; below that threshold, a valve blocks the return path and unused hydrogen is purged instead. A pressure-controlled relief valve releases excess inlet pressure, with the vented hydrogen diluted before discharge.

Source

Fuel cell anode pressure controller that opens a hydrogen exhaust valve to reduce pressure faster during sharp load reductions, instead of waiting for the stack to consume residual hydrogen. A PI controller uses filtered inlet pressure measurements to generate a control signal shared between the hydrogen supply and exhaust valves. Positive signals adjust the supply valve, with the exhaust valve operating only for periodic purging. Negative signals request pressure reduction, with a pressure-error threshold determining whether to force the exhaust valve open to assist depressurization.

Source

Fuel-cell hydrogen supply device that mechanically replenishes hydrogen after shutdown, prolonging the reducing atmosphere that protects the stack catalyst from oxidation. A high-pressure buffer supplies hydrogen through two parallel paths: an electronically controlled injection valve for normal operation and a mechanical pressure-reducing valve feeding the stack’s hydrogen chamber. The latter opens and closes mechanically to maintain hydrogen supply after shutdown. A circulation pump recycles hydrogen through the stack and a water separator, while an upstream shutoff valve can isolate the buffer from the hydrogen source.

Source

Fuel cell hydrogen pressure control that adjusts for cold inlet gas to limit pressure fluctuations and protect the proton exchange membrane. The controller selects a pressure-regulating valve opening from a lookup table using the required engine current, then corrects it for the gas-water separator’s operating state and the measured hydrogen inlet temperature. PID control further adjusts the resulting opening before commanding the valve, reducing pressure imbalance across the membrane.

Source

Fuel cell purge system with a variable-opening valve that allows small hydrogen purges during low-power operation, avoiding long waits between conventional on/off purges. The controller tracks accumulated fuel cell current and adjusts the valve opening through the duty ratio of a PWM signal. Above a preset accumulated-current threshold, it applies a 100% duty ratio. A calibration table links duty ratio to expected hydrogen discharge, helping set valve opening time. Purge duration can also vary with current accumulation rate, using longer purges at low current and shorter purges at high current.

Source

Fuel cell hydrogen circulation system with two parallel ejectors to control hydrogen supply pressure and flow independently of the engine controller. Each ejector has its own proportional valve and uses a fresh hydrogen jet to draw in unused hydrogen returning from the stack, mix the gases and feed them back into the stack. A local controller manages hydrogen circulation, while a safety valve relieves overpressure and a pulsed exhaust valve handles sudden pressure rises. Sound-absorbing mixing chambers or soundproof covers with noise-reducing gas passages suppress ejector noise.

Source

Fuel-cell hydrogen supply system that replenishes hydrogen while the vehicle is parked to protect the stack’s catalyst from oxygen entering through imperfect seals. A high-pressure hydrogen buffer feeds two separately controlled injection paths. The main controller operates the primary injection valves and hydrogen circulation pump during operation and shutdown, then powers off. A second controller manages a dedicated injection valve to prolong the protective hydrogen atmosphere after shutdown. Ambient and hydrogen pressure measurements guide control of the two systems. The circulation loop includes a water separator.

Source

Fuel cell system that boosts low-pressure hydrogen to the stack’s required supply pressure, reducing reliance on bulky high-pressure cylinders and their unused residual gas. A hydrogen pump feeds pressurized hydrogen through a buffer tank to an inlet valve assembly that supplies the stack and accepts recirculated hydrogen. Unused hydrogen leaving the stack passes through a water separator and one-way valve before reuse. A separate circulation pump circulates hydrogen on the hydrogen pump’s low-pressure side.

Source

Fuel-cell hydrogen supply control that avoids shutdown during restricted hydrogen flow without unnecessarily reducing power output. When supply-line pressure falls too far below the pressure required for the demanded current, the controller identifies the pressure peak where hydrogen supply balances consumption. It uses this measured peak to set a current limit matched to the available hydrogen supply, rather than imposing a fixed power reduction. If pressure falls below a further threshold, the controller can repeatedly cycle a hydrogen discharge valve to help clear contaminants and restore supply.

Source