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  Temperature zones in a solid oxide fuel cell auxiliary power unitUSPTO Application #: 20070269694Title: Temperature zones in a solid oxide fuel cell auxiliary power unit Abstract: A method for fuel cell system thermal management includes: maintaining a first zone at a first selected temperature range, maintaining a second zone at a second selected temperature range, and maintaining a third zone at a third selected temperature range. The second zone is in thermal communication with a first sensor and comprises a reformer, while the third zone is in thermal communication with a second sensor and comprises a fuel cell stack. The second selected temperature range is greater than the first selected temperature range, while the third selected temperature range is greater than the second selected temperature range. A thermal management system for use with an auxiliary power unit includes a first air control valve in fluid communication with a process air supply and a fuel reformer zone, the first air control valve in operable communication with a controller; a second air control valve in fluid communication with a process air supply and a hot zone, the second air control valve in electronic communication with the controller; a reformer zone temperature sensor in thermal communication with the fuel reformer and in operable communication with the controller; a hot zone temperature sensor in thermal communication with the hot zone and in operable communication with the controller; a first outlet at the reformer zone; and a second outlet at the hot zone. (end of abstract) Agent: Delphi Technologies, Inc. - Troy, MI, US Inventors: Karl Jacob Haltiner, Malcolm James Grieve, Kevin Richard Keegan, Michael Thomas Faville USPTO Applicaton #: 20070269694 - Class: 429024000 (USPTO) Related Patent Categories: Chemistry: Electrical Current Producing Apparatus, Product, And Process, Fuel Cell, Subcombination Thereof Or Methods Of Operating, Automatic Control Means, Temperature Dependent The Patent Description & Claims data below is from USPTO Patent Application 20070269694. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application claims the benefit of the dates of earlier filed provisional applications, having U.S. Provisional Application No. 60/201,568, filed on May 1, 2000, and U.S. Provisional Application No. 60/268,328, filed on Feb. 13, 2001, which are incorporated herein in their entirety. BACKGROUND [0002] Alternative transportation fuels have been represented as enablers to reduce toxic emissions in comparison to those generated by conventional fuels. At the same time, tighter emission standards and significant innovation in catalyst formulations and engine controls has led to dramatic improvements in the low emission performance and robustness of gasoline and diesel engine systems. This has reduced the environmental differential between optimized conventional and alternative fuel vehicle systems. However, many technical challenges remain to make the conventionally-fueled internal combustion engine a nearly zero emission system having the efficiency necessary to make the vehicle commercially viable. [0003] Alternative fuels cover a wide spectrum of potential environmental benefits, ranging from incremental toxic and carbon dioxide (CO.sub.2) emission improvements (reformulated gasoline, alcohols, etc.) to significant toxic and CO.sub.2 emission improvements (natural gas, etc.). Hydrogen has the potential to be a nearly emission free internal combustion engine fuel (including CO.sub.2 if it comes from a non-fossil source). [0004] The automotive industry has made very significant progress in reducing automotive emissions. This has resulted in some added cost and complexity of engine management systems, yet those costs are offset by other advantages of computer controls: increased power density, fuel efficiency, drivability, reliability and real-time diagnostics. [0005] Future initiatives to require zero emission vehicles appear to be taking us into a new regulatory paradigm where asymptotically smaller environmental benefits come at a very large incremental cost. Yet, even an "ultra low emission" certified vehicle can emit high emissions in limited extreme ambient and operating conditions or with failed or degraded components. [0006] One approach to addressing the issue of emissions is the employment of fuel cells, particularly solid oxide fuel cells (SOFC), in an automobile. A fuel cell is an energy conversion device that generates electricity and heat by electrochemically combining a gaseous fuel, such as hydrogen, carbon monoxide, or a hydrocarbon, and an oxidant, such as air or oxygen, across an ion-conducting electrolyte. The fuel cell converts chemical energy into electrical energy. A fuel cell generally consists of two electrodes positioned on opposite sides of an electrolyte. The oxidant passes over the oxygen electrode (cathode) while the fuel passes over the fuel electrode (anode), generating electricity, water, and heat. [0007] The fuel gas for the cell can be derived from conventional liquid fuels, such as gasoline, diesel fuel, methanol, or ethanol. The device, which converts the liquid fuel to a gaseous fuel suitable for use in a fuel cell, is known as a reformer. [0008] The long term successful operation of a fuel cell depends primarily on maintaining structural and chemical stability of fuel cell components during steady state conditions, as well as transient operating conditions such as cold startups and emergency shut downs. The support systems are required to store and control the fuel, compress and control the oxidant and provide thermal energy management. SUMMARY [0009] The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by a thermal management system. In an exemplary embodiment of the disclosure, a method of controlling temperature at an auxiliary power unit located in a vehicle includes: sensing a reformer zone temperature at a reformer zone; determining whether the reformer temperature is at a first selected temperature range; and adding a process air flow to the reformer zone if the reformer zone temperature rises above the selected temperature range. [0010] In one embodiment, a method of producing electricity at a fuel cell in a vehicle includes: adding a fuel and a reactant to a fuel reformer; producing a reformate at the fuel reformer; introducing the reformate to a fuel cell stack; and producing electrical power at the fuel cell stack. A reformer zone temperature is sensed at a reformer zone and it is determined whether the reformer zone temperature is at a first selected temperature range. If the reformer zone temperature rises above the first selected temperature range a first process air is added to the reformer zone. [0011] One embodiment of a method for fuel cell system thermal management, includes: maintaining a first zone at a first selected temperature range, maintaining a second zone at a second selected temperature range, and maintaining a third zone at a third selected temperature range. The second zone is in thermal communication with a first sensor and includes a reformer, while the third zone is in thermal communication with a second sensor and includes a fuel cell stack. The second selected temperature range is greater than the first selected temperature range, while the third selected temperature range is greater than the second selected temperature range. [0012] A thermal management system for use with an auxiliary power unit includes a first air control valve in fluid communication with a first process air supply and a fuel reformer zone, the first air control valve in operable communication with a controller; a second air control valve in fluid communication with a second process air supply and a hot fuel cell zone, the second air control valve in operable communication with the controller; a reformer zone temperature sensor in thermal communication with the fuel reformer and in operable communication with the controller; a hot zone temperature sensor in thermal communication with the hot zone and in electronic communication with the controller; a first outlet at the reformer zone; and a second outlet at the hot zone. BRIEF DESCRIPTION OF THE DRAWINGS [0013] Referring now to the drawing, which is meant to be exemplary and not limiting: [0014] FIG. 1 is a schematic of an exemplary fuel cell system with a thermal management system. DESCRIPTION OF A PREFERRED EMBODIMENT [0015] Application of a SOFC in a transportation vehicle imposes specific temperature, volume, and mass requirements, as well as "real world" factors such as fuel infrastructure, government regulations, and cost to be a successful product. This SOFC power generation system focuses on the power output necessary to serve as an auxiliary power unit on-board and not as the prime energy source of the vehicle. This auxiliary power unit would be carried on-board the vehicle as the electrical generator to supply the electrical loads that are on-board the vehicle. The system operates at higher overall efficiency (i.e., fuel energy input to electrical energy output) than current electromechanical alternator systems in current vehicles. The efficient operation of the SOFC system also permits electrical power to be generated on-board a vehicle even when the primary internal combustion engine is not operating (which will be critical to "no-idle" emissions laws being enacted in global regions). [0016] Referring to FIG. 1, a fuel cell auxiliary power unit 10 is schematically depicted. The auxiliary power unit 10 comprises a hot zone 22, a reformer zone 24 and an outside zone 26. Hot zone 22, which is an insulated enclosure, includes a fuel cell stack 28 and may include a waste energy recovery unit 30 and a micro-reformer 31. Hot zone 22 may reach temperatures of about 600.degree. C. to about 800.degree. C. once fuel cell stack 28 is operating at steady state, preferably about 725.degree. C. to about 775.degree. C. Reformer zone 24 is also an insulated enclosure and includes a fuel reformer 32. Waste energy recovery unit 30 and micro-reformer 31 are shown in hot zone 22, however, they could also be located in reformer zone 24. Reformer zone 24 may reach temperatures up to about 500.degree. C. and optimally, should be about 300.degree. C. to about 500.degree. C. once fuel reformer 32 is operating at steady state. Outside zone 26 includes a process air supply 34, air control valves 40 and 46, sensors (not shown), and controller 54 (e.g., an electronic controller). Outside zone 26 temperature is less than about 120.degree. C. [0017] Hot zone 22 is separated from reformer zone 24 by a thermal wall 36 so that the operating temperature of reformer zone 24 can be kept at a cooler temperature than the operating temperature of hot zone 22. Additionally, outside zone 26 is separated from both hot zone 22 and reformer zone 24 by a thermal wall 38 so that the temperature of outside zone 26 can be kept at cooler temperatures than the operating temperature of both hot zone 22 and reformer zone 24. [0018] Auxiliary power unit 10 operates by providing fuel reformer 32 with a fuel supply 56 and a process air flow 52, which is generated from process air supply 34. Optionally, fuel supply 56 is routed through micro-reformer 31 to fuel reformer 32. The process of reforming hydrocarbon fuels, such as gasoline, is completed to provide an immediate fuel source for rapid start up of fuel cell stack 28, as well as protecting fuel cell stack 28 by removing impurities. Fuel reforming can be used to convert a hydrocarbon (such as gasoline) or an oxygenated fuel (such as methanol) into hydrogen and byproducts (e.g., carbon monoxide, carbon dioxide, and water). Common approaches include steam reforming, partial oxidation, and dry reforming, and the like, as well as combinations comprising at least one of the foregoing approaches. [0019] Fuel reformer 32 produces a reformate 58, which can be directed through a waste energy recovery unit 30 or directly to fuel cell stack 28. Process air flow 52 can be provided through waste energy recovery unit 30 to fuel cell stack 28. Fuel cell stack 28 uses reformate 58 to create electrical energy 60 and waste byproducts such as spent/unreacted fuel 62 and spent air 64. Thermal energy from the flow of spent/unreacted fuel 62 and spent air 64 can optionally be recovered in a waste energy recovery unit 30, which can recycle the flow of fuel and waste heat to the fuel reformer and can also discharge a flow of reaction products 66 (e.g., water and carbon dioxide) from auxiliary power unit 10. Waste energy recovery unit 30 converts unused chemical energy (reformate 58) and thermal energy (exothermic reaction heat from the fuel cell stack 28) to input thermal energy for fuel cell stack 28 through the use of an integration of catalytic combustion zones and/or heat exchangers. Continue reading... Full patent description for Temperature zones in a solid oxide fuel cell auxiliary power unit Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Temperature zones in a solid oxide fuel cell auxiliary power unit patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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