Performance of Advanced Automotive Fuel Cell Systems with Heat Rejection Constraint
Explore the source record for details and available documents.
Heat rejection↗
SEARCH · Search NASA
Results for “AUTOMOTIVE FUELS”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Nano-structured non-platinum catalysts for automotive fuel cell application
Not Available
Serov, Alexey↗
Sorbent Material Property Requirements for On-Board Hydrogen Storage for Automotive Fuel Cell Systems.
Material properties required for on-board hydrogen storage in cryogenic sorbents for use with automotive polymer electrolyte membrane (PEM) fuel cell systems are discussed. Models are formulated for physical, thermodynamic and transport properties, and for the dynamics of H-2 refueling and discharge from a sorbent bed. A conceptual storage configuration with in-bed heat exchanger tubes, a Type-3 containment vessel, vacuum insulation and requisite balance-of-plant components is developed to determine the peak excess sorption capacity and differential enthalpy of adsorption for 5.5 wt% system gravimetric capacity and 55% well-to-tank (WTT) efficiency. The analysis also determines the bulk density to which the material must be compacted for the storage system to reach 40 g.L-1 volumetric capacity. Thermal transport properties and heat transfer enhancement methods are analyzed to estimate the material thermal conductivity needed to achieve 1.5 kg.min(-1) H-2 refueling rate. Operating temperatures and pressures are determined for 55% WTT efficiency and 95% usable H-2. Needs for further improvements in material properties are analyzed that would allow reduction of storage pressure to 50 bar from 100 bar, elevation of storage temperature to 175-200 K from 150 K, and increase of WTT efficiency to 57.5% or higher.
Ahluwalia, R. K.↗
GATE Center for Automotive Fuel Cell Systems at Virginia Tech
The Virginia Tech GATE Center for Automotive Fuel Cell Systems (CAFCS) achieved the following objectives in support of the domestic automotive industry: Expanded and updated fuel cell and vehicle technologies education programs; Conducted industry directed research in three thrust areas development and characterization of materials for PEM fuel cells; performance and durability modeling for PEM fuel cells; and fuel cell systems design and optimization, including hybrid and plug-in hybrid fuel cell vehicles; Developed MS and Ph.D. engineers and scientists who are pursuing careers related to fuel cells and automotive applications; Published research results that provide industry with new knowledge which contributes to the advancement of fuel cell and vehicle systems commercialization. With support from the Dept. of Energy, the CAFCS upgraded existing graduate course offerings; introduced a hands-on laboratory component that make use of Virginia Tech's comprehensive laboratory facilities, funded 15 GATE Fellowships over a five year period; and expanded our program of industry interaction to improve student awareness of challenges and opportunities in the automotive industry. GATE Center graduate students have a state-of-the-art research experience preparing them for a career to contribute to the advancement fuel cell and vehicle technologies.
30 DIRECT ENERGY CONVERSION↗
Status and Outlook for the U.S. Non-Automotive Fuel Cell Industry: Impacts of Government Policies and Assessment of Future Opportunities
Non-Automotive Fuel Cell Industry, Government Policy and Future Opportunities. Fuel cells (FCs)are considered essential future energy technologies by developed and developing economies alike. Several countries, including the United States, Japan, Germany,and South Korea have established publicly funded R&D and market transformation programs to develop viable domestic FC industries for both automotive and nonautomotive applications.
29 ENERGY PLANNING, POLICY, AND ECONOMY↗
Lightweight aircraft engines, the potential and problems for use of automotive fuels
A comprehensive data research and analysis for evaluating the use of automotive fuels as a substitute for aviation grade fuel by piston-type general aviation aircraft engines is presented. Historically known problems and potential problems with fuels were reviewed for possible impact relative to application to an aircraft operational environment. This report reviews areas such as: fuel specification requirements, combustion knock, preignition, vapor lock, spark plug fouling, additives for fuel and oil, and storage stability.
Patterson, D. J.↗
Selective Electrocatalysis Imparted by Metal-Insulator Transition for Durability Enhancement of Automotive Fuel Cells.
Repetitive start-up and shut-down events in polymer electrolyte membrane fuel cells for automotive applications lead to serious corrosion of the cathode due to an instantaneous potential jump that results from unintended air leakage into the anodic flow field followed by a parasitic oxygen reduction reaction (ORR) on the anode. Here we report a solution to the cathode corrosion issue during the start-up/shut-down events whereby intelligent catalyst design is used to selectively promote the hydrogen oxidation reaction (HOR) while concomitantly suppressing the ORR on the anode. Platinum thin layers supported on hydrogen tungsten bronze (Pt/HxWO3) suppressed the ORR by converting themselves into an insulator following exposure to oxygen, while selectively promoting the HOR by regaining metallic conductivity following subsequent exposure to hydrogen. The HOR-selective electrocatalysis imparted by a metal-insulator transition in Pt/HxWO3 demonstrated a remarkably enhanced durability of membrane electrode assemblies compared to those with commercial Pt/C catalysts.
Jung, Sang-Mun↗
Rejuvenation of automotive fuel cells
A process for rejuvenating fuel cells has been demonstrated to improve the performance of polymer exchange membrane fuel cells with platinum/ionomer electrodes. The process involves dehydrating a fuel cell and exposing at least the cathode of the fuel cell to dry gas (nitrogen, for example) at a temperature higher than the operating temperature of the fuel cell. The process may be used to prolong the operating lifetime of an automotive fuel cell.
30 DIRECT ENERGY CONVERSION↗
Development of Hydrocarbon Membrane for Automotive Fuel Cell Applications
The purpose of this project was to have Sandia National Laboratories (SNL) develop and ship membrane materials to Automotive Fuel Cell Cooperation Corporation (AFCC) to test under their industrial conditions. The results of this project was a close partnership with SNL and an established OEM. This project also gave the SNL material exposure to other large OEM such as Ford, Daimler and Gore. Also, it gave the SNL team confidence that the materials are being developed meet performance metrics required by industry. For the industry partner, this project expanded their view on what type of membrane materials could be used for their end application.
33 ADVANCED PROPULSION SYSTEMS↗
Survey Evidence on the Willingness of U.S. Consumers to Pay for Automotive Fuel Economy
Prospect theory, which was awarded the Nobel Prize in Economics in 2002, holds that human beings faced with a risky bet will tend to value potential losses about twice as much as potential gains. Previous research has demonstrated that prospect theory could be sufficient to explain an energy paradox in the market for automotive fuel economy. This paper analyzes data from four random sample surveys of 1,000 U.S. households each in 2004, 2011, 2012 and 2013. Households were asked about willingness to pay for future fuel savings as well as the annual fuel savings necessary to justify a given upfront payment. Payback periods inferred from household responses are consistent over time and across different formulations of questions. Mean calculated payback periods are short, about 3 years, but there is substantial dispersion among individual responses. Calculated payback periods do not appear to be correlated with the attributes of respondents. Respondents were able to quantitatively describe their uncertainty about both vehicle fuel economy and future fuel prices. Simulation of loss averse behavior based on this stated uncertainty illustrate how loss aversion could lead consumers to substantially undervalue future fuel savings relative to their expected value.
energy efficience↗
Leveraging automotive fuel cells can supply zero-emission peak power in the near-term
An increasingly decarbonized yet resilient power grid requires the corresponding build-out of dispatchable zero-emission resources to supply peak power. However, there is a recognized dearth of solutions which can serve multi-day peak demand events both cost-effectively and with near-term deployability. Here, we find that pairing low-cost automotive fuel cells with hydrogen storage in salt caverns can serve as a peaker plant at less than 500 US$/kW at present, a fraction of the cost of conventional fossil fuel-fired peakers. We demonstrate the peaker’s value for long duration storage by comparing it with pumped hydro and assessing its profitability within Texas’ energy-only market region. Although deployment of these peakers is constrained by the presence of salt caverns, we show that a number of sites in the United States and Europe are endowed with suitable salt formations, while utilizing hydrogen storage in pressurized containers could form a location-agnostic peak power solution.
25 ENERGY STORAGE↗
Performance and cost of automotive fuel cell systems with ultra-low platinum loadings.
An automotive polymer-electrolyte fuel cell (PEFC) system with ultra-low platinum loading (0.15 mg-Pt cm{sup -2}) has been analyzed to determine the relationship between its design-point efficiency and the system efficiency at part loads, efficiency over drive cycles, stack and system costs, and heat rejection. The membrane electrode assemblies in the reference PEFC stack use nanostructured, thin-film ternary catalysts supported on organic whiskers and a modified perfluorosulfonic acid membrane. The analyses show that the stack Pt content can be reduced by 50% and the projected high-volume manufacturing cost by >45% for the stack and by 25% for the system, if the design-point system efficiency is lowered from 50% to 40%. The resulting penalties in performance are a <1% reduction in the system peak efficiency; a 2-4% decrease in the system efficiency on the urban, highway, and LA92 drive cycles; and a 6.3% decrease in the fuel economy of the modeled hybrid fuel-cell vehicle on the combined cycle used by EPA for emission and fuel economy certification. The stack heat load, however, increases by 50% at full power (80 kW{sub e}) but by only 23% at the continuous power (61.5 kW{sub e}) needed to propel the vehicle on a 6.5% grade at 55 mph. The reduced platinum and system cost advantages of further lowering the design-point efficiency from 40% to 35% are marginal. The analyses indicate that thermal management in the lower efficiency systems is very challenging and that the radiator becomes bulky if the stack temperature cannot be allowed to increase to 90-95 C under driving conditions where heat rejection is difficult.
30 DIRECT ENERGY CONVERSION↗
Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy
Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Automotive fuel cell stack and system efficiency and fuel consumption based on vehicle testing on a chassis dynamometer at minus 18 °C to positive 35 °C temperatures
In this work we present an in-depth laboratory technology assessment of a 2016 Toyota Mirai Fuel Cell (FC) vehicle based on chassis dynamometer testing. The 114.6 kW FC stack has a high dynamic response, which makes this powertrain a FC-dominant hybrid electric vehicle. The measured peak efficiency is 66.0% FC stack and 63.7% FC system with an idle hydrogen flow rate of 4.39 g/hr. The high FC system efficiencies at low loads match typical vehicle power spectrums, resulting in a high average vehicle efficiency of 62% compared to 45% and 23% for a hybrid electric vehicle and a conventional vehicle, respectively. An energy breakdown accounts for the FC stack losses, FC system losses, air compressor loads, and heater loads for different drive cycles and different thermal conditions. The cold-start North American city drive cycle (UDDS) energy consumption values are, respectively, 758, 581, 226, and 321 Wh/km at ambient conditions of -18 degrees C, -7 degrees C, -25 degrees C and 35 degrees C with 850 W/m 2 of solar loading. The FC system shutdown and startup processes at temperatures below the freezing point contribute to the increased hydrogen consumption. Additionally, the raw test data files are available for download, thus providing the research community with a public reference data on a modern production automotive FC system.
08 HYDROGEN↗
Status and Outlook for the U.S. Non-Automotive Fuel Cell Industry: Impacts of Government Policies and Assessment of Future Opportunities
Fuel cells (FCs) are considered essential future energy technologies by developed and developing economies alike. Several countries, including the United States, Japan, Germany, and South Korea have established publicly funded R&D and market transformation programs to develop viable domestic FC industries for both automotive and non-automotive applications. Important non-automotive applications include large scale and small scale distributed combined heat and electrical power, backup and uninterruptible power, material handling and auxiliary power units. The U.S. FC industry is in the early stages of development, and is working to establish sustainable markets in all these areas. To be successful, manufacturers must reduce costs, improve performance, and overcome market barriers to new technologies. U.S. policies are assisting via research and development, tax credits and government-only and government-assisted procurements. Over the past three years, the industry has made remarkable progress, bringing both stack and system costs down by more than a factor of two while improving durability and efficiency, thanks in part to government support. Today, FCs are still not yet able to compete in these markets without continued policy support. However, continuation or enhancement of current policies, such as the investment tax credit and government procurements, together with continued progress by the industry, appears likely to establish a viable domestic industry within the next decade.
30 DIRECT ENERGY CONVERSION↗
Engineering Challenges of Solution and Slurry-Phase Chemical Hydrogen Storage Materials for Automotive Fuel Cell Applications
In this work, we present the research findings of the DOE-funded Hydrogen Storage Engineering Center of Excellence (HSECoE) related to liquid-phase and slurry-phase chemical hydrogen storage media and their potential as future hydrogen storage media for automotive applications. Chemical hydrogen storage media other than neat liquid compositions will prove difficult to meet the DOE system level targets. Solid- and slurry-phase chemical hydrogen storage media requiring off-board regeneration are impractical and highly unlikely to be implemented for automotive applications because of the formidable task of developing solid- or slurry-phase transport systems that are commercially reliable and economical throughout the entire life cycle of the fuel. Additionally, the regeneration cost and efficiency of chemical hydrogen storage media is currently the single most prohibitive barrier to implementing chemical hydrogen storage media. Ideally, neat liquid-phase chemical hydrogen storage media with net-usable gravimetric hydrogen capacities of greater than 7.8 wt% are projected to meet the 2017 DOE system level gravimetric and volumetric targets. The research presented herein is a collection of research findings that do not in and of themselves warrant a dedicated manuscript. However, the collection of results do, in fact, highlight the engineering challenges and short-comings in scaling up and demonstrating fluid-phase ammonia borane and alane compositions that all future materials researchers working in hydrogen storage should be aware of.
25 ENERGY STORAGE↗
Status and Outlook for the U.S. Non-Automotive Fuel Cell Industry: Impacts of Government Policies and Assessment of Future Opportunities
Fuel cells (FCs) are considered essential future energy technologies by developed and developing economies alike. Several countries, including the United States, Japan, Germany, and South Korea have established publicly funded R&D and market transformation programs to develop viable domestic FC industries for both automotive and non-automotive applications. Important non-automotive applications include large scale and small scale distributed combined heat and electrical power, backup and uninterruptible power, material handling and auxiliary power units. The U.S. FC industry is in the early stages of development, and is working to establish sustainable markets in all these areas. To be successful, manufacturers must reduce costs, improve performance, and overcome market barriers to new technologies. U.S. policies are assisting via research and development, tax credits and government-only and government-assisted procurements. Over the past three years, the industry has made remarkable progress, bringing both stack and system costs down by more than a factor of two while improving durability and efficiency, thanks in part to government support. Today, FCs are still not yet able to compete in these markets without continued policy support. However, continuation or enhancement of current policies, such as the investment tax credit and government procurements, together with continued progress by the industry, appears likely to establish a viable domestic industry within the next decade.
30 DIRECT ENERGY CONVERSION↗
Slurry-Based Chemical Hydrogen Storage Systems for Automotive Fuel Cell Applications
In this paper, the system designs for hydrogen storage using chemical hydrogen materials in an 80 kWe fuel cell, light-duty vehicle are described. Ammonia borane and alane are used for these designs to represent the general classes of exothermic and endothermic materials. The designs are then compared to the USDRIVE/DOE developed set of system level targets for on-board storage. While most of the DOE targets are predicted to be achieved based on the modeling, the system gravimetric and volumetric densities were more challenging and became the focus of this work. The resulting system evaluation determined that the slurry is majority of the system mass. Only modest reductions in the system mass can be expected with improvements in the balance of plant components. Most of the gravimetric improvements will require developing materials with higher inherent storage capacity or by increasing the solids loading of the chemical hydrogen storage material in the slurry.
chemical hydrogen storage↗