Browse Topic: Hydrogen storage

Items (96)
SAE J2601 establishes the protocol and process limits for hydrogen fueling of vehicles with total volume capacities greater than or equal to 49.7 L. These process limits (including the fuel delivery temperature, the maximum fuel flow rate, the rate of pressure increase, and the ending pressure) are affected by factors such as ambient temperature, fuel delivery temperature, and initial pressure in the vehicle’s compressed hydrogen storage system. SAE J2601 establishes standard fueling protocols based on either a look-up table approach utilizing a fixed pressure ramp rate, or a formula-based approach utilizing a dynamic pressure ramp rate continuously calculated throughout the fill. Both protocols allow for fueling with communications or without communications. The table-based protocol provides a fixed end-of-fill pressure target, whereas the formula-based protocol calculates the end-of-fill pressure target continuously. For fueling with communications, this standard is to be used in conjunction with SAE J2799. An important factor in the performance of hydrogen fueling is the station’s dispensing equipment cooling capability and the resultant fuel delivery temperature. There are three fuel delivery temperature categories denoted by a “T” rating: T40, T30, and T20, where T40 is the coldest. Under reference conditions, SAE J2601 has a performance target of a fueling time of 3 minutes and a state of charge (SOC) of 95 to 100% (with communications), which can be achieved with a T40-rated dispenser. However, with higher fuel delivery temperature dispenser ratings (T30 or T20) and/or at high ambient temperatures, fueling times may be longer. Table 1 depicts the scope of SAE J2601 and potential work items for future revisions within this or other documents of the SAE J2601 series. SAE J2601 includes protocols which are applicable for two pressure classes (35 MPa and 70 MPa), three fuel delivery temperatures categories (-40 °C, -30 °C, -20 °C) and compressed hydrogen storage system sizes (total volume classification) from 49.7 to 248.6 L (35 MPa ➔ H35, and 70 MPa ➔ H70), and from 248.6 L and above (H70 only). Future versions of SAE J2601 work may incorporate warmer fuel delivery temperatures (-10 °C and ambient) and smaller total volume capacities for motorcycles and other applications. The fueling protocols herein were developed based on a set of key assumptions described in Section 7 and Appendix A. These assumptions should be carefully considered in the development and implementation of an on-board compressed hydrogen storage system. In particular, hydrogen storage systems with properties which do not fall within the parameters in Table A3 should be further evaluated to confirm compatibility with the protocols herein.
Fuel Cell Standards Committee
This standard specifies the communications hardware and software requirements for fueling hydrogen surface vehicles (HSV), such as fuel cell vehicles, but may also be used where appropriate, with heavy-duty vehicles (e.g., busses) and industrial trucks (e.g., forklifts) with compressed hydrogen storage. It contains a description of the communications hardware and communications protocol that may be used to refuel the HSV. The intent of this standard is to enable harmonized development and implementation of the hydrogen fueling interfaces. This standard is intended to be used in conjunction with the hydrogen fueling protocols in SAE J2601 and nozzles and receptacles conforming with SAE J2600.
Fuel Cell Standards Committee
Aircraft electric propulsion technology review – A shift from turbofan to the ethrust era2018-36-00969/3/2018
Following the electrification trend observed in the automotive industry, the idea of an electric propulsion aircraft has also drawn attention and investments from a range of aviation industry stakeholders (including the world's largest aerospace companies) focused on both fuel burning reduction and environmental performance improvement (greenhouse gases (GHG), pollutants and noise emissions) potential of electric propulsion technology. Electric propulsion has the potential to provide more efficient, cleaner, quieter and more profitable aviation services, with potential benefits to both airlines and passengers. Furthermore, with its inherent quiet feature, it has also the potential to lead to a reassessment of the role of airports along the world cities, as well as revitalize regional short-haul flights and helps the launch of air service into underserved regions around the world. From a technical perspective , the aviation propulsion electrification strategy might involves the integration of electric powetrains into aircrafts into the i) all electric; ii) hybrid and iii) turboelectric approach. The former might rely solely on batteries as energy sources and requires engines up to 300 times more powerful than current available electric aviation motors (currently used for two-seater prototypes). The hybrid configuration uses gas turbines, for turbofan propulsion, and to charge batteries (with turbogenerators), which also provides energy for electric propulsion for one or more phases of flight. Finally, turboelectric configurations do not rely on batteries to supply propulsion energy. Rather, they use gas turbines to drive electric generators to feed distributed electric driven fans, with their inherent aerodynamic benefits associated with distributed propulsion. Hybrid architectures might provide a more realistic near-term pathway, while key enabling technologies - batteries, high power electric motors and superconducting electric power - reach the required improvement, into an expected 10 to 20 year timeframe. The most likely niche of the industry to first commercially launch this groundbreaking technology is the commuter and regional jet category, with a 50 to 70 passenger capacity and a short to mid range. This work is supposed to present an overview of aircraft electric propulsion technology, followed by an assessment of its potential operational, environmental and economic benefits, as well as the required technological breakthrough to reach the electric thrust era.
Barbosa, Fábio Coelho
Field Validation of the MC Default Fill Hydrogen Fueling Protocol2015-01-11774/14/2015
Appendix H of the SAE J2601 standard defines a development hydrogen fueling protocol named the MC Default Fill, which builds upon the foundation of the table based protocol, utilizing the same assumptions, boundary conditions, and process limits as the current standard. The MC Default Fill facilitates the following beyond the table based protocol: 1) the potential to provide faster, more consistent fueling times for fuel cell electric vehicle customers, and 2) the ability to continuously and dynamically adjust to a wide range of dispenser fuel delivery temperatures, allowing for more flexibility in station design. Computer simulations and laboratory bench tests were previously conducted and documented, validating the function and operation of the protocol. Through the application of the MC Default Fill to a commercial hydrogen dispenser, and by conducting a large number of fills on multiple hydrogen storage systems under a wide range of operating conditions, this paper will document the real world performance and behavior of the protocol. Issues related to practical implementation of the protocol will also be discussed, as well as enhancements and revisions to the protocol that were realized from this field application. The objective of this effort is to provide validation of the MC Default Fill protocol in the field.
Mathison, StevenHanda, KiyoshiMcGuire, TimothyBrown, TylerGoldstein, ToddJohnston, Michael
Validation and Sensitivity Studies for SAE J2601, the Light Duty Vehicle Hydrogen Fueling Standard2014-01-19904/1/2014
The worldwide automotive industry is currently preparing for a market introduction of hydrogen-fueled powertrains. These powertrains in fuel cell electric vehicles (FCEVs) offer many advantages: high efficiency, zero tailpipe emissions, reduced greenhouse gas footprint, and use of domestic and renewable energy sources. To realize these benefits, hydrogen vehicles must be competitive with conventional vehicles with regards to fueling time and vehicle range. A key to maximizing the vehicle's driving range is to ensure that the fueling process achieves a complete fill to the rated Compressed Hydrogen Storage System (CHSS) capacity. An optimal process will safely transfer the maximum amount of hydrogen to the vehicle in the shortest amount of time, while staying within the prescribed pressure, temperature, and density limits. The SAE J2601 light duty vehicle fueling standard has been developed to meet these performance objectives under all practical conditions. It defines the fueling protocol and operational fueling parameters that ensure both station and vehicle maintain their safety limits (e.g. SAE J2578) while delivering optimal fueling performance. The results of the standard allow a representative FCEV under the target conditions to be completely fueled within three minutes. The team working on SAE J2601 performed extensive simulation and sensitivity studies which were validated through laboratory testing with representative CHSS hardware and field testing with fuel cell vehicles. This report documents the lab and field validation testing for SAE J2601.
Schneider, JesseMeadows, GrahamMathison, Steven R.Veenstra, Michael J.Shim, JihyunImmel, RainerWistoft-Ibsen, MortenQuong, SpencerGreisel, ManfredMcGuire, TimothyPotzel, Peter
State of the Art and Future Trends of Electric Drives and Power Electronics for Automotive Engineering2014-01-18884/1/2014
Discussions about the optimal technology of propulsion systems for future ground vehicles have been raising over the last few years. Several options include different types of technologies. However, those who are advocating conventional internal combustion engines are faced with the fact that fossil fuels are limited. Others favor hydrogen fuel as the solution for the future, either in combination with combustion engines or as an energy carrier for fuel cells. In any case, the production and storage of hydrogen is an ongoing challenge of numerous research works. Finally, there are battery-electric or hybrid propulsion systems in use, gaining more and more popularity worldwide. Ongoing advances in power electronics help to improve control systems within automotive applications. New developed or designed components enable more efficient system architectures and control. This paper includes a detailed comparison of different electric drive technologies, e.g. a DC motor, an asynchronous and synchronous motor in battery-electric or hybrid drivetrain configurations. Parameters for future drive architectures, such as high torque and power output, high system efficiency, low mass, low energy consumption, very low exhaust gas emissions, and low costs are introduced and discussed. Advantages and disadvantages of different drivetrain configurations are specified, evaluated, and discussed. Additionally, a selection of advances in power electronics is listed and described in detail. Practical examples of electric drive systems are given explicitly and conclusions for future development are made. The publication closes with an overview of current components in use and presents an outlook to future trends.
Fabian, JürgenHirz, MarioKrischan, Klaus
Validation of the Localized Fire Test Method for On-Board Hydrogen Storage Systems2014-01-04214/1/2014
The localized fire test provided in the Global Technical Regulation for Hydrogen Fuel Cell Vehicles gives two separate test methods: the ‘generic installation test - Method 1′ and the ‘specific vehicle installation test - Method 2′. Vehicle manufacturers are required to apply either of the two methods. Focused on Method 2, the present study was conducted to determine the characteristics and validity of Method 2. Test results under identical burner flame temperature conditions and the effects of cylinder protection covers made of different materials were compared between Method 1 and Method 2. The following results were obtained: (1) Methods 1 and 2 produced nearly identical results when the minimum temperature profile in the GTR test procedure was followed in both cases. (2) A steel protection cover on the cylinder significantly lowered cylinder surface temperatures during the fire test until activation of the thermal pressure relief device (TPRD). (3) A thermoplastic cover on the cylinder melted during the fire test and produced an engulfing pool fire during the localized fire portion of the test that accelerated activation of the TPRD. Since the advantage of early TPRD is highly dependent on where and how the pool fire is generated by the melting thermoplastic material.
Tamura, YohsukeTakeuchi, MasayukiMaeda, KiyotakaOhtsuka, NoriakiSato, Kenji
Overcoming the Range Limitation of Medium-Duty Battery Electric Vehicles through the use of Hydrogen Fuel-Cells2013-01-24719/24/2013
Battery electric vehicles possess great potential for decreasing lifecycle costs in medium-duty applications, a market segment currently dominated by internal combustion technology. Characterized by frequent repetition of similar routes and daily return to a central depot, medium-duty vocations are well positioned to leverage the low operating costs of battery electric vehicles. Unfortunately, the range limitation of commercially available battery electric vehicles acts as a barrier to widespread adoption. This paper describes the National Renewable Energy Laboratory's collaboration with the U.S. Department of Energy and industry partners to analyze the use of small hydrogen fuel-cell stacks to extend the range of battery electric vehicles as a means of improving utility, and presumably, increasing market adoption. This analysis employs real-world vocational data and near-term economic assumptions to (1) identify optimal component configurations for minimizing lifecycle costs, (2) benchmark economic performance relative to both battery electric and conventional powertrains, and (3) understand how the optimal design and its competitiveness change with respect to duty cycle and economic climate. It is found that small fuel-cell power units provide extended range at significantly lower capital and lifecycle costs than additional battery capacity alone. And while fuel-cell range-extended vehicles are not deemed economically competitive with conventional vehicles given present-day economic conditions, this paper identifies potential future scenarios where cost equivalency is achieved.
Wood, EricWang, LijuanGonder, JeffreyUlsh, Michael
Finite Element Analysis of Composite Over-wrapped Pressure Vessels for Hydrogen Storage2013-01-24779/24/2013
This paper presents 3D finite element analysis performed for a composite cylindrical tank made of 6061-aluminum liner overwrapped with carbon fibers subjected to a burst internal pressure of 1610 bars. As the service pressure expected in these tanks is 700 bars, a factor of safety of 2.3 is kept the same for all designs. The optimal design configuration of such high pressure storage tanks includes an inner liner used as a gas permeation barrier, geometrically optimized domes, inlet/outlet valves with minimum stress concentrations, and directionally tailored exterior reinforcement for high strength and stiffness. Filament winding of pressure vessels made of fiber composite materials is the most efficient manufacturing method for such high pressure hydrogen storage tanks. The complexity of the filament winding process in the dome region is characterized by continually changing the fiber orientation angle and the local thickness of the wall. The research work presented in this paper reveals that the continuously changing angle orientation and local laminate thickness in the dome regions can be modeled by a unique approach that utilizes suitable transformations of the macromechanical composite properties and the local coordinate system. Accurate representation of the exterior reinforcement allows for detailed analysis of the dome structure as well as the nozzle/valve connection. A metallic insert is utilized to connect the dome structure to the valve system. A comparative study between different insert geometries and locations in the dome has been performed. It shows that an insert extending through the dome geometry increases the resulting stress at the cylinder-dome juncture. The most effective design approach entails an insert to the boss region.
William, Gergis W.Shoukry, SamirPrucz, JackyEvans, Thomas
A Load Balancing Strategy for Increasing Battery Lifetime in Electric Vehicles2013-01-04994/8/2013
Decreasing fossil energy sources require the search for alternative ways of individual transport. An important step is the electrification of the drive train and further vehicle components, enabling a total control of the overall energy flow while at the same time offering more degrees of freedom in optimizing the vehicle architecture. This paper describes an energy management system for battery electric vehicles. Main component of the system is a load balancing strategy which smoothens the energy flow and reduces high current fluctuations, reducing energy losses while increasing the battery lifetime. The first part of the paper describes a central ECU, which has been developed as a vehicle management unit. Driving strategy as well as the energy management strategy are implemented on this ECU. A bench test has been developed to test the ECU hardware as well as software in a laboratory environment. The second part of the paper describes in detail the simulation model of the vehicle used, a Tata Indica Vista EV. The model concentrates on the energy flow within the vehicle and includes sub-models of all relevant components of the vehicle, for example the traction and starter batteries, or loads like the heating system. A comparison of simulation and measurements proves the validity of the simulation model. The last part of the paper describes the energy management strategy. Energy savings, the reduction of load peaks and the reduction of microcycles have been evaluated using the simulation model during different drive cycles, indicating an increase of the battery lifetime.
Masjosthusmann, ChristopherBueker, UlrichKöhler, UlrichDecius, Nikolaus
Ultra-Compact Power System for Long-Endurance Small Unmanned Aerial Systems2012-01-217710/22/2012
Air-launched Small Unmanned Aerial Systems (SUASs) provide critical information to warfighters, but are currently limited by the power and energy available from small electric propulsion systems. This paper describes proof-of-concept testing of a novel power system for SUASs. The power system comprises a compact hydrogen generator and a hydrogen PEM fuel cell. The hydrogen generator uses ammonia borane (AB) as a solid chemical hydrogen storage material and heats the AB to produce hydrogen through thermal decomposition. The innovative ignition and control process generates highly pure hydrogen on-demand from a system that is very compact, lightweight, and rugged. We built a proof-of-concept hydrogen generator and used it to supply hydrogen to a small PEM fuel cell. The proof-of-concept generator used prototypical AB, heat source, control scheme, and purification media to absorb trace amounts of ammonia, borazine, and carbon monoxide (CO). The hydrogen generator operated as expected, producing hydrogen as needed to maintain the supply pressure within specified bounds. The fuel cell produced 4 A/8.6 V for 15 minutes, amounting to 8.6 W-hr of electricity. We measured the fuel cell's current/voltage characteristics before and after the test, and found no measurable change due to operation with AB-generated hydrogen. Based on these data, we scaled up the design of the proof-of-concept unit and produced a design for a 720 W-hr hydrogen generator with a very high hydrogen density (5.6 wt% and 36 g H₂/L). The hydrogen generator is extremely simple and well-suited for operation in an air-launched SUAS. Combined with a compact fuel cell, our system should enable a small power system for SUAS with an overall energy density in the range of 350 to 600 W-hr/kg.
Izenson, MichaelMagari, PatrickBieszczad, JerryKiwada, George
Innovative Dense Lightweight Design for On-Board Hydrogen Storage Tank2012-01-20619/24/2012
The hydrogen economy envisioned in the future requires safe and efficient means of storing hydrogen fuel for either use on-board vehicles, delivery on mobile transportation systems or high-volume storage in stationary systems. The main emphasis of this work is placed on the high -pressure storing of gaseous hydrogen on-board vehicles. As a result of its very low density, hydrogen gas has to be stored under very high pressure, ranging from 350 to 700 bars for current systems, in order to achieve practical levels of energy density in terms of the amount of energy that can be stored in a tank of a given volume. This paper presents 3D finite element analysis performed for a composite cylindrical tank made of 6061-aluminum liner overwrapped with carbon fibers subjected to a burst internal pressure of 1610 bars. As the service pressure expected in these tanks is 700 bars, a factor of safety of 2.3 is kept the same for all designs. The results indicated that a stress reduction could be achieved by a geometry change only, which could increase the amount of pressure sustained inside the vessel and ultimately increase the amount of hydrogen stored per volume. Such reductions in the stresses will decrease the thickness dimension required to achieve a particular factor of safety in a direct comparison to a cylindrical design.
William, Gergis W.Shoukry, SamirPrucz, Jacky
Development of a Vehicle-Level Simulation Model for Evaluating the Trade-Off between Various Advanced On-Board Hydrogen Storage Technologies for Fuel Cell Vehicles2012-01-12274/16/2012
One of the most critical elements in engineering a hydrogen fuel cell vehicle is the design of the on-board hydrogen storage system. Because the current compressed-gas hydrogen storage technology has several key challenges, including cost, volume and capacity, materials-based storage technologies are being evaluated as an alternative approach. These materials-based hydrogen storage technologies include metal hydrides, chemical hydrides, and adsorbent materials, all of which have drawbacks of their own. To optimize the engineering of storage systems based on these materials, it is critical to understand the impacts these systems will have on the overall vehicle system performance and what trade-offs between the hydrogen storage systems and the vehicle systems might exist that allow these alternative storage approaches to be viable. To gain a better understanding of the interactions that exist between various materials-based hydrogen storage systems and the vehicle system as well as the engineering challenges that exist when integrating one of these systems with a vehicle, the National Renewable Energy Laboratory (NREL) developed a vehicle-level model designed to be sensitive to these issues. The Hydrogen Storage Simulation Model (HSSIM) was developed under the Hydrogen Storage Engineering Center of Excellence (HSECoE) as a specialized tool that could be used to assist in the design and engineering of materials-based hydrogen storage systems being considered by the HSECoE. This tool is designed to not only allow for understanding key trade-offs, but also to have a seamless integration with the HSECoE fuel cell and detailed hydrogen storage system models and to evaluate progress towards the U.S. Department of Energy's hydrogen storage technical targets. This model has been integrated with a fuel cell model developed by Ford Motor Company in a HSECoE common modeling framework developed by United Technologies Research Center and other HSECoE partners. This paper focuses on the development, structure, and validation of the vehicle model HSSIM and summarizes its integration within the framework. HSSIM and the framework are then used to obtain trade-offs for various specific materials-based storage system designs. This includes hydrogen storage sizing analyses, mass compounding analyses, range versus volume studies, and vehicle and component performance analyses, such as acceleration rates and fuel cell and energy storage interactions.
Thornton, MatthewBrooker, AaronCosgrove, JonathonVeenstra, MichaelPasini, Jose Miguel
Control System for Sensing the Differential Pressure Between Air and Hydrogen in a PEFC2012-01-12284/16/2012
Stress induced by an excessive difference in pressure between the air and the hydrogen in polymer electrolyte fuel cells degrades membrane durability. Controlling such stress improves the durability and solves one of the problems hampering commercialization of fuel cell electric vehicles. Hydrogen pressure can be raised more rapidly than the air pressure by regulating the pressure of the high-pressure hydrogen storage tank. However, the response for reducing the hydrogen pressure varies depending on the level of current generation. The air pressure can be reduced rapidly by releasing air, whereas it takes longer to raise the air pressure owing to compression of the air taken in from the atmosphere. The method proposed here for designing the control system of the air pressure and mass flow rate assumes that the system is based on the use of a mathematical model, whereas the hydrogen pressure control system does not employ a mathematical model and treats the consumption of hydrogen during power generation as a disturbance. The air pressure is predicted using transfer functions and the hydrogen pressure is made to follow the predicted value. In addition, the air pressure is made to follow the larger of either the reference pressure or the hydrogen pressure. This paper first describes the application of a sliding mode control theory for controlling the air pressure and flow control system using the mathematical model. It then explains the configuration of the control system for sensing the differential pressure within a specified range. Experimental results are finally presented to validate the control performance achieved with the proposed design method.
Asai, Yoshitomo
Long Term Hydrogen Vehicle Fleet Operational Assessment2011-01-22999/13/2011
The U. S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) National Automotive Center (NAC) owns a fleet of ten Hydrogen Hybrid Internal Combustion Engine (H2ICE) vehicles that have been demonstrated in various climates from 2008 through 2010. This included demonstrations in Michigan, Georgia, California and Hawaii. The fleet was consolidated into a single location between July 2009 and April 2010. Between July of 2009 and January of 2011, data collection was completed on the fleet of H2ICE vehicles deployed to Oahu, Hawaii for long-term duration testing. The operation of the H2ICE vehicles in Hawaii utilized standard operation of a non-tactical vehicle at a real-world military installation. The vehicles were fitted with data acquisition equipment to record the operation and performance of the H2ICE vehicles; maintenance and repair data was also recorded for the fleet of vehicles. Over the year-long demonstration, the vehicles were driven by a wide range of military services including the Army, Air Force, Navy, Pacific Command (PACOM) and National Guard; each service had different drive cycles. Drivers were trained in the operation of the H2ICE vehicles and the safe use of hydrogen, and were surveyed to solicit their feedback on the H2ICE vehicles. The demonstration of this fleet of H2ICEs identified maintenance issues associated with long term operation of the vehicles, as well as user concerns that would need to be addressed if hydrogen vehicles are going to be transitioned from research and development fleets to general commercial use vehicles. Vehicle performance data collected showed the fuel efficiency of the fleet of vehicles and the vehicle's reliability.
Eick, StevenParker, ReneWhiting, Greg
Effect of Control Strategy on the Performance of a Fuel Cell Hybrid Electric Auto Rickshaw2011-01-11744/12/2011
The basis for this paper is a project whose objective is to examine the feasibility of converting a diesel powered auto rickshaw to fuel cell/battery hybrid electric operation. One of the most important factors that influences the performance of hybrid vehicles is the energy management and power distribution between the different energy sources. This paper examines the impact of the control strategy on performance. The optimization of the energy management system is a supervisory control problem. One of the most popular cost functions for optimization involves the sum of fuel consumption and equivalent fuel consumption from the battery state of charge (SOC), commonly referred to as the equivalent consumption minimization strategy (ECMS). In this paper, a modified ECMS is tested together with three different management control strategies on a model of a fuel cell hybrid electric rickshaw using a realistic drive cycle. The 1 st tested was a fuel cell load following strategy in which the power of the fuel cell tracked the demanded power and the role of the battery was to supplement power when demand exceeded the capacity of the fuel cell. The 2 nd tested was a battery load following strategy in which the fuel cell shuts down when the SOC is above a given threshold, and turns on when the SOC is below a given threshold. The 3rd tested was an optimized fuel cell strategy in which fuel cell operation was restricted to its most efficient region. The strategies are documented via flow charts. A performance comparison of the different strategies is presented, where the main performance measures are given by distance traveled, fuel economy and speed tracking error.
Abu Mallouh, MohammedAl-Marouf, MohamadSurgenor, BrianPeppley, Brant
Development of the Methodology for FCV Post-crash Fuel Leakage Testing Incorporated into SAE J25782010-01-01334/12/2010
This paper explains the new methodology for post-crash fuel leakage testing of Fuel Cell Vehicles (FCVs) and other hydrogen vehicles utilizing compressed hydrogen storage systems. This methodology was incorporated into SAE J2578 that was revised and published in January, 2009. The new methodology is based on the concept in FMVSS 303 that specifies post-crash fuel leakage test method and criteria for CNG vehicle and adopted some modifications. Specifically, the following items are addressed: (1) Allowable leakage can be accurately evaluated in test even with large size tank that obtains only small pressure drop when a given amount of leakage occurs. A new method to deal with the influence of measurement errors was devised. (2) Even though only one option of test gas and initial filling pressure is accepted in FMVSS 303, new methodology for hydrogen system allows helium and hydrogen at reduced pressure as alternatives in addition to hydrogen at service pressure. Test with hydrogen at service pressure is easy to perform, but two alternatives are attractive for test safety if leakage occurs during the crash test. Those alternatives are intended to provide results that are equivalent to test with hydrogen at service pressure. In order to improve the approach used in FMVSS303, a new simulation method was developed that can estimate the pressure change in the storage system after crash based on the mass leakage that could be occurring due to crash damage. Based on this simulation results, approximation equations for calculation of test time and leakage mass criteria were derived including compensations for test gas temperature and initial filling pressure. The purpose of this paper is to provide the details relative to the simulation procedures and approximation equations used in SAE J2578 as it is envisioned that this approach will serve as the basis for future regulation of allowable post-crash fuel loss in FCVs and hydrogen vehicles.
Kinoshita, NaokiChang, TommyScheffler, Glenn
Thermal Behavior in Hydrogen Storage Tank for Fuel Cell Vehicle on Fast Filling2007-01-06884/16/2007
The current hydrogen storage systems for fuel-cell vehicles are mainly a compressed hydrogen storage type, but it is known that the temperature inside the tank commonly increases while the tank is being filled with hydrogen. This study examines filling methods that prevent the temperature from exceeding the designed temperature of the tank. In order to propose a filling method that suppresses the temperature rise inside the tank and achieves filling within a short time, fast-filling tests were conducted on test tanks designed for fast filling of fuel cell vehicles. The detailed influences of the differences in type of tank and filling pressure on the rate of the internal temperature increase were investigated. Thermal responses were measured at various parts inside and outside the tank while varying the filling pressure, type of tank, tank capacity, filling time, and filling pattern, using a test tank that allows multi-point measurement of the internal temperature. Remarkable differences in the rate of temperature increase during filling (ΔT) were observed between different types of tank, and characteristic differences in temperature were observed in the distribution of temperatures in the tank. In the type 4 tank, in particular, the temperature in the upper area inside the tank was higher than in other parts of the tank, depending on the filling rate. This paper indicates that if temperature, internal pressure and capacity of the tank are known when filling starts, it may be possible to shorten the filling time by selecting the optimum filling rate and to predict the maximum temperature reached in the tank.
Hirotani, RyuichiTerada, ToshihiroTamura, YousukeMitsuishi, HiroyukiWatanabe, Shogo
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