The compact van with 50 kW AC induction motor serves as a research platform for scientists and engineers in the newly created Global Alternative Propulsion Centre in Rüsselsheim, Germany. The objective is to develop this future-oriented, environmentally compatible technology to market readiness by 2004.

In terms of volume production, Opel considers the combination of fuel-cell and electric drive to possess more potential than any other known alternative propulsion system. Compared with modern internal combustion engines the fuel-cell offers significant improvements in efficiency with almost zero emissions of sulphur dioxide (SO2) and nitrogen oxides (NOx). Carbon dioxide (CO2) output is almost halved.

The basic principle of the fuel-cell used in the Zafira is an electro-chemical process in which hydrogen reacts with oxygen to generate electricity, with water as a by-product. In order to avoid a costly and space-consuming storage of hydrogen in special canisters, methanol is carried in a conventional fuel tank.

Opel and GM are exploring multiple sources for hydrogen including gasoline, methanol, natural gas and pure hydrogen.


Global Network: International Center for Alternative Propulsion Systems
Opel’s parent company, General Motors, has performed research into fuel-cell technology in cars since the 1960s. These activities were extended with the official establishment this year of the Global Alternative Propulsion Centre (GAPC) near Rüsselsheim. Led by Dr. J. Byron McCormick and Dr. Erhard Schubert, this centre is responsible for Opel’s and GM’s research into alternative propulsion systems. The GAPC also includes the North American research facilities at Warren (Michigan) and Rochester (New York).

The physicists, chemists, process engineers and electronics experts at the three GAPC centres intend to develop a fuel-cell-powered vehicle to market readiness by 2004.

The vehicle will meet the demands of everyday driving and also set new standards in terms of environmental compatibility. Roominess, performance and safety will then correspond to those of conventionally powered cars.

Vehicles with fuel-cell technology generate almost no pollutants and are quiet, thanks to electric drive. They also have a significantly higher efficiency rating compared to cars with internal combustion engines.

Peter H. Hanenberger, Opel’s Management Board member for Engineering, therefore sees good prospects for the fuel-cell as a source of power for cars: "In the future we want to offer customers fuel-cell cars that set new standards for environmental compatibility. At the same time they should deliver good performance and be fun to drive.

"Thanks to fuel cell technology, the car of the future will emit hardly any pollutants when driven. Compared with today’s cars with their internal combustion engines, it will generate only about half as much carbon dioxide, and the electric motor will run very quietly. That goes for small cars and large vehicles. The automobile propelled by fuel-cells and electric engines will be clean, powerful and comfortable. Opel/GM will get it ready to go to market."


Conversion Process: Methanol is Source of Hydrogen
In the Zafira concept car, a fuel processing system converts the methanol into a hydrogen-rich gas with CO2 as a by-product. A small amount of carbon monoxide (CO) generated during this process is oxidized by a catalytic converter to carbon dioxide (CO2) before the gas is fed to the fuel-cell stack. The fuel-cell Zafira produces near zero emissions of nitrogen oxides (NOx) and about half the CO2 of gasoline engines.

Thanks to the fuel-cell technology’s high energy conversion efficiency, this propulsion system compensates for methanol’s lower power density compared with gasoline or diesel fuel. The vehicle’s range on a tank of fuel is therefore similar to that of conventionally powered vehicles.

A fuel-cell consists of two electrodes, the anode and the cathode, separated by a polymer membrane. Hydrogen gas is fed to the anode and dissociates into positive hydrogen ions (protons) in the presence of a platinum catalyst on the anode side. The protons migrate through the membrane to the cathode. The electrons are conducted in the form of useable electric current through an external circuit. Oxygen from air is fed to the cathode, combining with the protons and electrons from the external circuit to form pure water and heat.

One cell can generate 0.7 to 0.9 volt, so a series of cells are collected in a stack. The electricity generated supplies the 50 kW AC induction motor, which drives the front wheels via a single-speed gearbox. Opel can draw on considerable experience in electric drive, thanks to cars like the Astra Impuls and the EV1.

The fuel-cell Zafira’s electric motor, battery pack and power control electronics are housed in the engine compartment of the 1850 kg vehicle. The battery provides transient power and storage of electricity gained from regenerative braking.


Flexible: Modular Layout of Components
The fuel-cell stack, the fuel conversion system and the methanol tank are located in the rear of the Zafira. The modular layout of the prototype systems gives the engineers maximum flexibility in the testing of components and configurations. Development continues to reduce the size of fuel-cell components for more efficient packaging of the vehicle.

A static research platform based on the Opel Sintra represented the previous development status about six months ago at the Geneva Motor Show.