Fuel cells start to look real
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GM HydroGen1
Last year General Motors introduced the HydroGen1, a vehicle it claims features the automotive industry's most advanced operational fuel-cell stack. The HydroGen1 is a five-seat concept vehicle based on Opel's Zafira compact van. It is powered by a 56-kW (75-hp) electric motor supplied with current from a 60-kW PEM fuel-cell stack that runs on liquid hydrogen. The fuel-cell system generates between 125 and 200 V depending on load conditions. The car has a top speed of 135 km/h (85 mph) and a range of about 400 km (250 mi) on a tank of hydrogen. With 251 N•m (185 lb•ft) available from a standstill, GM claims the fuel-cell vehicle will accelerate from 0 to 97 km/h (0 to 60 mph) in less than 16 s.
 GM's HydroGen1. |
According to GM, it has developed an industry first - the ability to draw power from a fuel-cell stack frozen at temperatures as low as -40°C (-40°F). GM's previous fuel-cell stack took over 6 min to achieve full power when frozen at -20°C (-4°F). The current seventh-generation fuel-cell stack now achieves significant power levels quickly at even lower temperatures. At -20°C (-4°F), full power is achieved in just 30 s, and at -30°C (-22°F), power is achieved in just 60 s.
GM engineers are also focused on making the fuel-cell affordable without sacrificing performance. Fuel-cell stack designs under development target issues that drive cost, including component materials, design for manufacture, and precious metal content. According to Byron McCormick, Co-executive Director of GM's Global Alternative Propulsion Center, the eleventh- and twelfth-generation fuel-cell units are now in the lab. "We're developing a new fuel-cell stack each quarter," he said. Erhard Schubert, the Center's other co-director, claims that the HydroGen1's "systems architecture is better than, and its stack performance is superior to, its rivals."
The HydroGen1's hydrogen fuel is stored in liquid cryogenic form in a 60-L (16-gal), stainless steel tank insulated with a glass-fiber mat. The use of liquid hydrogen helps ameliorate packaging problems significantly. The tank is located under the rear seat. Most importantly, the fuel-cell stack itself has been reduced in size and is now claimed to be 15% smaller than rival fuel-cell units. The complete stack - comprising 195 cells - and a 55-kW, three-phase ac motor, has a mass of just 68 kg (150 lb). The whole assembly fits in the Zafira's standard engine bay. The location of the liquid hydrogen tank raises rear-seat height 30 mm (1.2 in) and also means the cargo area loses its fold-away seats and sits 100 mm (3.9 in) higher. Otherwise, the HydroGen1's functionality is unimpaired. Company engineers add that computer crash simulations indicate that the tank's location would not be a safety hazard in an accident. Overall, the five-seat project vehicle's mass is 150 kg (330 lb) greater than the standard Zafira's at 1420 kg (3135 lb).
Larry Burns, GM Vice President for Research and Development, said that GM and ExxonMobil have developed a better way to extract hydrogen from gasoline. "Our joint progress on gasoline processor technology means that clean, efficient fuel-cell-electric vehicles could be in consumers' garages by the end of the decade," he said. The gasoline reformer is said to have an 80% conversion efficiency. With such a fuel processor, said Burns, GM could build a fuel-cell vehicle that uses 40% of the energy in gasoline - almost double what a typical car does today in average driving. Although the current system is not emissions-free, it nonetheless emits just half the carbon dioxide and significantly less carbon monoxide and nitrogen oxides than current gasoline engines.
In 1999, Toyota and GM reached an agreement to cooperate in research and development of vehicles with advanced environmental technology, with special focus on fuel-cell, hybrid, and electric vehicles. Said McCormick, "We're working closely with Toyota to try to reduce the risk of developing next-generation vehicles. It helps to compare our ideas and approaches. It also avoids duplication of effort." Toyota has set 2003 as its target for market introduction of fuel-cell vehicles.
Ford Focus FCV
Ford's Focus FCV will serve as the base for its first production fuel-cell vehicle, scheduled to go on sale by 2004. The FCV has a range of about 160 km (100 mi) and power that's comparable to a current Focus, said Bruce Kopf, Director of Engineering for Th!nk, Ford's alternative fuel vehicle division. The vehicle runs on compressed hydrogen gas.
 Ford Focus FCV. |
Kopf said the production Focus FCV will likely be sold mostly for use in business fleets that can install equipment for handling hydrogen. He noted that reducing the cost of fuel-cell power is the biggest technical challenge, one that Ford won't likely solve before 2010.
The FCV uses the Ballard Mark 900 fuel cell, which features an 80-kW power output. Its electric drivetrain is based on the traction drive in the electric Ranger pickup truck.
Volkswagen Bora HyMotion
 VW Bora HyMotion. |
