June 2000
The first fuel cell car appeared more than 30 years ago
A Long Tradition of Alternative Propulsion at Opel and GM
Powerful electric motors came of age decades ago
Rüsselsheim. During their research and development work on pollutant-free automobile propulsion in the future, the scientists and engineers at the Global Alternative Propulsion Center (GAPC) are constantly exploring new territory, but they never have to start from scratch. On the contrary: On both sides of the Atlantic, they can draw upon considerable know-how and extensive experience, since research into alternative propulsion technologies has a long tradition at Opel and General Motors (GM).
GM in Detroit built a road-going fuel cell car more than 30 years ago. The system consisted of 32 fuel cell blocks in series, and was installed in a van. The energy was supplied from steel cylinders filled with hydrogen. The motor of this revolutionary vehicle had a continuous output rating of 32 kilowatts, and its maximum action radius without refueling was about 200 kilometers. Despite its promising performance, the project was abandoned due to unfavorable general conditions for fuel cell technology in the 1960s, such as low fuel prices and the virtual absence of environmental awareness.
Fuel cell technology was pursued further at General Motors in the mid-80s, when American engineers and chemists developed a new, compact type of power-producing cell with a proton-conducting membrane as an electrolyte (PEM) and very high power density. In subsequent years, the world's biggest car manufacturer's scientists and technicians continued their research and came up with numerous new solutions for alternative automobile propulsion, some of which were granted research funds by the government. Examples include a transportable reformer that breaks down methanol thermally to yield hydrogen and thus solves the fuel supply problem, and several fuel cell blocks rated at up to 50 kW. Important secondary assemblies and the electronic systems required for fuel cell propulsion were also developed and the system was adapted step by step to meet the requirements of the car of the future.
GAPC: Concentration of fuel cell activities at Opel and GM
These years of extensive basic research and testing began to yield results just a few months after Opel and GM had concentrated their fuel cell activities at the three GAPC centers: In September 1998, the Opel and GM developers surprised the experts at the Paris Automobile Salon with a road-going experimental study based on the Zafira compact van. It had a 50 kW (68 hp) fuel cell unit, fuel preparation by methanol reformer and a three-phase AC traction motor. It could reach a maximum speed of 120 km/h and accelerate from a standstill to 100 km/h in around 20 seconds. The follow-up model presented at the 2000 Geneva Automobile Salon uses hydrogen fuel and accelerates even faster: It reaches 100 km/h in just 16 seconds.
This performance makes it clear that the GAPC has plenty of technical fuel cell know-how and that the engineers' lengthy experience and competence in powerful electric propulsion systems are standing them in good stead. In Rüsselsheim, extensive development work began as early as 1970 on an Opel GT prototype. This sports coupé had two DC electric motors with a combined power output of 100 kW (136 hp), supplied from nickel cadmium batteries. With this driveline, the GT established three world records for electric vehicles on the Formula 1 racetrack in Hockenheim, Germany; one of them was the maximum speed of 189 km/h.
Strong foundation: Years of experience with powerful electric propulsion systems
Another electric prototype was built in 1990: the Impuls 1, based on the Opel Kadett. This car was less likely to break records but was very much closer to reality. Its 100 volt direct current shunt-wound motor had a power output of 16 kW (22 hp), its top speed was 100 km/h and its maximum range on its nickel cadmium batteries was 80 kilometers.
The subsequent Astra Impuls 2 model had two powerful three-phase AC asynchronous traction motors, each of which drove a front wheel via integral planetary gears. The two motors were supplied with electrical energy from 32 in-series lead-acid battery modules, and had a total power output of 85 kW (115 hp). The "electric Astra" weighed only 225 kilograms more than a comparable conventional-fuel car, its maximum speed was 120 km/h and it accelerated from a standstill to 50 km/h in six seconds. Ten Astra Impulse 3 cars with high-energy sodium/nickel chloride batteries demonstrated their practical usefulness during a large-scale test on the German island of Rügen in the Baltic. Between 1993 and 1997, these test vehicles covered a total of more than 350,000 kilometers. They also proved their long-term durability in a two-year European Union field test in the "Euregio" three-country region between Aachen, Germany, Maastricht in the Netherlands and Liège, Belgium.
In the mid-90s, tests with the multi-functional Combo Plus compact transporter equipped with a time-saving battery exchange system were also very successful. Thanks to its 45 kW three-phase AC asynchronous traction motor that was also used on an electric Corsa built by Opel engineers for testing purposes, its maximum speed was 110 km/h. The electric energy for both vehicles came from sodium/nickel chloride batteries.
On the other side of the Atlantic, the successors to the GM engineers who had developed an electrically powered truck to series maturity as early as 1916 made steady progress in the development of an alternative automobile propulsion system. After sensational concept studies such as the Impact electric sports car with its maximum speed of 160 km/h or the large sedan HX3 with hybrid driveline, General Motors in 1996 became the first car manufacturer to launch a powerful two-seater car with an electric motor suitable for everyday use in the USA. This was the EV1, a front-wheel drive car with a powerful electric drive train developed by GM. It consists of a 101 kW (137 hp) AC motor, a single-speed transmission with 2:1 reduction ratio and a highly advanced electronic regulating system for managing the auxiliary power steering, on-board power supply and auxiliaries. The electrical energy for the motor is supplied by 26 nickel metal hybrid battery modules; the car accelerates to 100 km/h in 8.5 seconds and its maximum speed is governed to 130 km/h. The action radius is 150 kilometers; the car weighs 1295 kilograms and is capable of converting its braking energy back into electricity.
GM Precept: A study with parallel hybrid or fuel cell propulsion
The latest climax of this development work was the high-economy, low-emission GM Precept hybrid concept vehicle, presented for the first time at the International Motor Show in Detroit in January 2000. At 0.163, it has the lowest aerodynamic drag coefficient of any sedan world-wide. The five-seat car of futuristic design has a three-phase 35 kW (47 hp) electric motor driving the front wheels and a 40 kW (54 hp) 1.3-liter three-cylinder turbocharged diesel with common-rail direct injection to drive the rear wheels. In conjunction with the electronic control system and the concept study's systematic weight-saving structure, the efficient parallel hybrid principle makes an average fuel consumption of only 2.94 liters per 100 kilometers possible.
Like the fuel cell Zafira with its hydrogen fuel source, the Precept study is a result of Opel's and General Motor's determination to develop powerful, environmentally-friendly and, most important of all, affordable cars for future mobility. This is made particularly evident by a fuel cell study based on the Precept that was also shown for the first time in Detroit: The hydrogen required to generate electrical energy is not stored at very low temperature in a tank on the vehicle, but in a new form of hydride accumulator.
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