摘要:
A thermally-activated exhaust treatment device, such as a catalytic converter (20) adapted to control exhaust emissions in a vehicle, includes a core having an inner housing (21) and a catalytic material (27) chosen to reduce undesirable emissions from the exhaust of a combustion engine. A jacket includes an outer housing (22) enclosing the inner housing (21) but characteristically not contacting the inner housing (21). The inner and outer housings (21, 22) include walls (30, 31) forming a vacuum-drawn sealed insulation cavity (26) around the inner housing (21). A chamber (60) positioned adjacent the inner housing (21) includes low melting point metal phase change material (61). A thermal management system is operably connected to the insulation cavity (26) that is constructed to control heat flow from the inner housing (21) to maximize the time the catalytic material (27) is within a predetermined optimum temperature operating range or limit catalyst maximum temperature.
摘要:
A thermally-activated exhaust treatment device, such as a catalytic converter, for vehicles includes a core having an inner housing and a catalytic material. A jacket includes an outer housing enclosing the inner housing, but characteristically not contacting the inner housing. The inner and outer housings include walls forming a vacuum-drawn sealed insulation cavity around the inner housing. A temperature-activated variable insulator device is positioned within the outer housing and includes a hydrogen source and controls for controlling the variable insulator device. A vacuum-maintenance device is incorporated into the insulation cavity, and includes a small container, getter material positioned in the container, and a porous member allowing gas in the insulation cavity to communicate with the getter material. A multi-layered radiation shield is positioned in the vacuum space and is loosely coupled to the inner housing. A vacuum detector includes a visible indicator of the vacuum in the insulation cavity.
摘要:
A thermally-activated exhaust treatment device, such as a catalytic converter (20); for vehicles includes a core having an inner housing (21) and a catalytic material (27, 27′). A jacket includes an outer housing (22) enclosing the inner housing (21) but characteristically not contacting the inner housing (21). The inner and outer housings (21, 22) includes walls (30, 31) forming a vacuum-drawn scaled insulation cavity (26) around the inner housing (21). A temperature-activated variable insulator device is positioned within the outer housing (22) and includes a hydrogen source (32) and controls for controlling the variable insulator device. A vacuum-maintenance device is incorporated into the insulation cavity (26), and includes a small container, getter material positioned in the container, a porous member allowing gas in the insulation cavity (26) to communicate with the getter material. A multi-layered radiation shield is position in the vacuum space and is loosely coupled to the inner housing (21). A vacuum detector includes a visible indicator of the vacuum in the insulation cavity (26).
摘要:
A process for controlling the length of a purge and the purge rate of a fuel cell stack at system shut-down so as to provide the desired amount of stack humidity. The membrane humidification is measured at system shut-down by a high frequency resistance sensor that detects membrane humidification and provides the measurement to a controller. The controller controls the compressor that provides cathode input air to the fuel cell stack so that the time of the purge and the flow rate of the purge provide a desired membrane humidity for the next start-up.
摘要:
A method and apparatus for thermal control of air flow in a fuel cell system, capable of accurately controlling the temperature of the air stream entering the water vapor transfer unit, maintaining a desired temperature set-point, and minimizing the time required for the air stream to reach the optimum operating temperature.
摘要:
A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber therebetween. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food.
摘要:
A fuel cell system includes a water vapor transfer unit and a fluid flow distribution feature, the water vapor transfer unit including a first plate having a plurality of first flow channels for receiving a flow of a first fluid therein, and a second plate having a plurality of second flow channels for receiving a flow of a second fluid therein. The fluid flow distribution feature is configured to control at least one of a volume of flow of the first fluid through the first flow channels and a volume of flow of the second fluid through the second flow channels, wherein at least one of a flow distribution of the first fluid across the first plate and a flow distribution of the second fluid across the second plate is varied.
摘要:
A system and method for quickly heating a fuel cell stack at fuel cell system start-up. The fuel cell system includes a three-way valve positioned in the anode exhaust that selectively directs the anode exhaust gases to the cathode input of the fuel cell stack so that hydrogen in the anode exhaust gas can be used to heat the fuel cell stack. During normal operation when the fuel cell stack is at the desired temperature, the three-way valve in the anode exhaust can be used to bleed nitrogen to the cathode exhaust.
摘要:
A method for quickly and efficiently heating a fuel cell stack at system start-up. The method uses and prioritizes various stack heat sources based on their efficiency to heat the stack. A thermal set-point for heating the stack to the desired temperature is determined based on the ambient temperature and, the stack cooling fluid temperature. The set-point is then compared-to the stack heating provided by the heat sources that are operating through normal system start-up operation. If more heat is necessary to reach the set-point, the method may first charge a system battery using stack power where the load causes the fuel cell stack to heat up. If additional heating is still required, the method may then turn on a cooling fluid heater, then flow a small amount of hydrogen into the cathode inlet stream to provide combustion, and then increase the compressor load as needed.
摘要:
A system and method for reducing RH cycling of the membranes in a fuel cell stack. A control algorithm damps a power request signal using a first order filter during low power transients so that the fuel cell stack continues generating power at a higher rate than is requested. The excess power generated by the stack is used to recharge a battery in the fuel cell system. The damped power signal is weighted so that more fuel cell stack power is provided for a low battery state of charge unless stack power is provided for a high battery state of charge.