Opel Makes Major Advances in Fuel Cell Development - "HydroGen3" Bye Bye OPEC?

HydroGen3 prototype with more compact propulsion system

Fuel cell Zafira "HydroGen1" sets international records

New fuel cell unit with higher power density Rüsselsheim. On the path to volume production of fuel cell vehicles, the development team at Opel and General Motors' Global Alternative Propulsion Center (GAPC) made a number of major advances in 2001. In September, at the Frankfurt Motor Show (IAA), the team presented a prototype called "HydroGen3", which is based on the Opel Zafira and has an optimized propulsion system that allows a particularly compact arrangement of the individual components in the vehicle. Like its predecessor, "HydroGen1", which is also based on the Zafira compact van, HydroGen3 uses pure hydrogen as its fuel. Shortly after the IAA, the experts at GAPC introduced a new fuel cell stack, which sets new standards with its high power density of 1.75 kW per liter.

Earlier in the year, HydroGen1 demonstrated how much progress Opel and GM's experts had already made in the field of fuel cell propulsion. In tests in the US State of Arizona, the concept vehicle set a total of 15 international records for fuel cell cars. At the "Michelin Challenge Bibendum", too, an international competition for environmentally friendly vehicles, the Opel prototype powered by pure hydrogen was the only fuel cell passenger car to master the 350 kilometers from Los Angeles to Las Vegas.

"HydroGen3" Points the Way to Series Production

The primary aim of the HydroGen3 project was to improve the performance and day-to-day use of the propulsion system. As part of this enhancement program, the GAPC development team succeeded in dispensing altogether with some of the components that were necessary in HydroGen1. A useful side-effect was that the weight of the vehicle was further reduced towards the target of 1590 kilograms. The most prominent component the development team managed to do without in HydroGen3 was the high-performance buffer battery. In HydroGen1, this energy storage unit had the job of dealing with performance peaks in the drive unit, but the optimized fuel cell system of HydroGen3 is now able to provide the required power immediately on its own. Not only has this saved nearly 100 kilograms in weight, the greater compactness of the system also means that the floor height of the load area in the hydrogen-powered Zafira is now the same as that of the production-line model. The full load space of the Zafira in the five-seater arrangement (600 liters) is thus now also available in HydroGen3.

Pure hydrogen is used as the fuel to generate the power for the electric motor of the fuel cell prototype. This hydrogen is stored on board HydroGen3 in liquid form in a stainless steel tank at a temperature of -253 °C. A vacuum in the gap between the inner and outer walls, plus several layers of thin aluminum foil, ensure optimum protection against heat radiation from outside. With its volume of 68 liters, the fuel tank, which is positioned in front of the rear axle below the rear seat (the seat has been raised 25 millimeters to accommodate it), has an operating radius of around 400 kilometers. The stack, which is significantly more compact than its predecessor, develops a constant power of 94 kW (previously 80 kW) and a peak of 129 kW (previously 120 kW). The fuel cell stack supplies the power for a 60 kW (82 hp) three-phase asynchronous motor. With this highly effective drive line, the fuel cell Zafira travels from 0 to 100 km/h in 16 seconds, and has a top speed of 150 km/h.

Compact and Powerful: The New Fuel Cell Unit

Shortly after HydroGen3 made its debut, GM and Opel presented an even more efficient fuel cell unit at a technology conference in London, UK. With a figure of 1.75 kW per liter, it sets new standards in terms of its power density. The dimensions of the stack are 819 x 140 x 508 millimeters (58 liters), it weighs 82 kg and generates a continuously available electrical output of 102 kW. If required, the stack can also cope with higher peaks: As with HydroGen3, up to 129 kW is available for short periods.

Like the fuel cell unit of the Opel prototype, this latest generation stack also has membranes in the individual cells which need no additional external humidifying components in order to carry out their electrolyte function for power generation. The efficient fuel cell unit also boasts excellent cold-start characteristics. At a temperature of -20 °C, the full power is available after only 30 seconds - an important factor for the day-to-day use of the fuel cell technology in cars.

HydroGen1 Masters even the Toughest Conditions

HydroGen1 demonstrated that it was already at the forefront of technical development in May 2001 during an endurance test program at General Motors' Mesa desert proving grounds in the US State of Arizona. Despite the extreme heat conditions in the desert, it succeeded in setting a total of 15 new international records for fuel cell vehicles in terms of both distance (10/100/ 500/1000 kilometers and 10/100/500 miles) and time (1/6/12/24 hours). In the 24-hour marathon, the prototype covered a total of 1387 kilometers at an average speed of 57.79 km/h. During the record drives, air temperatures reached 35 °C in the shade and up to 65 °C on the tarmac.

In October, HydroGen1 again demonstrated its abilities at the "Michelin Challenge Bibendum 2001" in California. In a strong international field with competitors from almost all European, American and Japanese manufacturers, HydroGen1 was the only fuel cell-powered passenger car to finish the 350 kilometer course from Los Angeles to Las Vegas. Along the route, the vehicles had to overcome an altitude difference of 1350 meters and outside temperatures of 32 °C. In various individual disciplines on the California Speedway near Los Angeles, HydroGen1 performed particularly well in the emissions, noise and slalom categories. For the successful integration of the fuel cell system in the vehicle, the hydrogen-powered Zafira was also awarded a "Bibendum Design Award".

On-Board Gasoline Reforming as an Interim Solution

Widespread availability of hydrogen at filling stations is still some time away. Until then, the experts at Opel and GM regard on-board reforming as a useful interim solution. Reforming is basically the process of dissolving hydrogen out of gasoline. In August 2001, the GAPC development team presented a prototype based on the Chevrolet Pickup S 10 with the world's first gasoline reformer on board a vehicle.

The development of fuel cell technology at Opel is receiving added impetus from the alliance with a number of partners. Since 1999, General Motors and Opel have been cooperating closely in this field with Toyota. In 2001, GM also entered into an alliance with the Japanese car maker, Suzuki, on the application of the future technology in small cars. Other research cooperation agreements have been signed with the Canadian Hydrogenics Corporation (Toronto) and the US specialists Giner Inc. (Newton, Massachusetts). The cooperation with Hydrogenics covers not only the development but also the marketing of fuel cell systems. The focus of the alliance with Giner is on tank-filling systems for hydrogen and stationary fuel cell applications for generating energy. An agreement with Quantum Technologies (Irvine, California) has been signed to promote the development of storage systems for hydrogen.