|
|
. 
. .
..
. . . .
© 1999-2002 Copyright
|
Opel AG: Opel Fuel Cell Zafira 2000 Hydrogen-Powered, Road-Going, Fuel Cell Zafira
Its range is about 400 km. This hydrogen-powered concept vehicle demonstrates one aspect of the experimental work for some 200 scientists and technicians at the German and US-based Opel/GM Global Alternative Propulsion Center (GAPC). Opel/GM is developing the technologies that will lead to market introduction of a broad range of vehicles.
Opel showed its first experimental vehicle powered by this extremely environmentally compatible technology at the Geneva Automobile Show in 1997, and a second vehicle - based on the current Zafira - at the Paris Motor Show in 1998. Whereas both these experimental vehicles converted methanol to hydrogen-rich gas in a so-called reformer, the fuel cell unit of the latest experimental vehicle obtains its energy directly from a special tank. At this year´s Detroit Motor Show, General Motors presented the Precept FCEV (fuel cell electric vehicle), which features an advanced, compact chemical hydride system for on-board hydrogen storage. In the fuel cell Zafira, the hydrogen tank is a cylindrical container with a length of about one meter and a diameter of 400 mm. It stores up to 75 liters of liquid hydrogen (LH2) fuel weighing only about 5 kilograms. This clean fuel is stored on board the vehicle at a temperature of -253°C. This is made possible by special glass fiber mat tank insulation, which has the same insulating properties as a layer of polystyrene several meters thick.
The stainless steel tank is stowed away safely in the interior of the concept vehicle under the second row of seats and the baggage compartment, and can withstand an acceleration force of up to 30 g (1 g = 9.81 m/s²). Its crash behavior in numerous computer simulations has also been tested. The second row of seats and the baggage area are 30 and 100 mm higher than in the volume-production Zafira. The fuel cells and the electric motor are situated under the front hood. The "stack" of fuel cell units assembled by the GPAC experts occupies an area of 590 × 270 × 500 mm (length × width × height). Its working principle is based on an electrochemical process in which hydrogen reacts with oxygen to produce direct electrical energy. The Zafira stack has a maximum output of 80 kW, generated by the 195 single cells in the block at a process temperature of about 80°C. Their electric current is supplied to a 55 kW, three-phase, AC synchronous electric motor, which drives the front wheels through fixed ratio gears. The complete unit weighs only 68 kg. A further advantage of the compact assembly, which produces current very rapidly in the fuel cells and therefore reacts spontaneously to every accelerator pedal movement, is its high propulsion power. The motor's maximum torque of 251 Nm is available all the time and accelerates the fuel-cell version of this compact van, which weighs 1575 kg (compared with the standard Zafira's 1425 kg) from a standstill to 100 km/h in 16 seconds. The electric motor can even reach higher performance peaks: if required 60 kW (82 hp) and a maximum torque of 305 Nm are available. These figures show the progress made by the global team at the GAPC research centers in Mainz-Kastel, Germany, Rochester, New York, USA and Warren, Michigan, USA in achieving their aim of reaching series production with an automobile using fuel cell technology. The amount of experience gained by General Motors since 1964 in this area has been of great help and has led quite recently to a further breakthrough with regard to suitability for day-to-day use: For the first time, experts at the research institute led jointly by Dr. Byron J. McCormick and Dr. Erhard Schubert succeeded in repeatedly starting a fuel cell unit at an ambient and stack temperature of -20°C and producing electrical energy directly at full capacity. Tests are now even further advanced and are carried out at -40°C. The development of fuel cell technology fully suitable for everyday use is receiving additional impetus from strategic alliances with strong partners such as the Japanese automobile manufacturer Toyota and a number of mineral oil companies. The most important joint objectives include setting up the necessary infra-structure, the reduction of costs, and the development of lighter and more compact storage technology for the fuel of the future. This is, according to GAPC Co-Director Dr. Erhard Schubert, "most definitely hydrogen, because a propulsion system using hydrogen fuel cells has optimum efficiency, emits nothing but water vapor, runs practically noise-free and offers at the same time a high degree of driving pleasure." (February 2000)
|
|
