TOKYO — General Motors Corp. of the United States and German automakers DaimlerChrysler AG and BMW AG will unveil their respective gasoline-electric hybrid car strategies during the North American International Auto Show in Detroit that begins Sunday, according to automotive industry sources.

The U.S. and German companies earlier agreed to join forces in developing a new hybrid propulsion system for vehicles to enable the three firms to catch up with Toyota Motor Corp, the world's frontrunner in the hybrid car field, The alliance has adopted GM's all-new hybrid technology.

Leading automakers in Europe, Japan and the United States have been either competing or collaborating in an attempt to secure a market share large enough to set the world's de facto standard for hybrid technology. Honda Motor Co., for example, has been pressing ahead with a hybrid project on its own.

In autumn last year, GM, DaimlerChrysler and BMW--which originally had embarked on hybrid development schemes separately--agreed to a joint research and development project.

The three-way collaboration aims to jointly develop a system to control a gasoline engine and electric motor and technology to make the motor as compact as possible.

GM and the two German automakers want new hybrid vehicles to debut from 2007, the automotive sources said. The three companies are expected to make their hybrid car marketing plans known during the Detroit show.

The GM technology is known as a two-mode hybrid system--an electronically variable automatic transmission with low-speed and high-speed motors that support the gasoline engine.

The low-speed mode is for in-city, stop-and-start driving, while the high-speed mode is for expressway driving. As both motors linked to a control unit operate selectively, depending on the vehicle's speed, the GM system can enhance fuel efficiency.

Furthermore, the combination of two modes can lead to the downsizing of each motor, enabling related devices, such as a battery smaller, to be made smaller.

The U.S.-German alliance, which believes GM's modular hybrid technology could also be superior in terms of cost efficiency, intends to approach other automakers to promote the system together.

Toyota's hybrid technology is a single-mode system that uses an electric motor alone for low-speed driving and the gasoline engine and the motor in parallel for high-speed driving.

The largest Japanese automaker envisages annual sales of about 1 million hybrid vehicles by 2010.

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Source: Knight Ridder/Tribune Business News