Hybrids get thumbs up

In a deal that has been hailed as a major vote of confidence for hybrid drive systems, GM, DaimlerChrysler and BMW have announced that they are to collaborate on the technology at a new Hybrid Development Centre in Michigan.

With fuel costs soaring, the link between two of the world’s ‘big three’ car manufacturers and one of Europe’s largest automotive groups suggests hybrids are poised to enter the mainstream sooner rather than later.

The partners will pool their expertise to develop a ‘two-mode’ hybrid system that, it is claimed, will provide the performance and environmental benefits of hybrid technology in both stop-start city traffic and on motorways. Other hybrid drives, such as that used on the Toyota Prius, save fuel in stop- and-go traffic, but are generally regarded to be less efficient at high speeds.

The proposed system will essentially be an enhanced version of technology that has already been developed by GM’s hybrid researchers for use on its diesel-hybrid transit buses. This will be tweaked and tailored by the three companies for their own specific applications.

‘Each group willindividually integrate the hybrid system into the design and manufacturing of vehicles in accordance with their brand-specific requirements,’ confirmed GM Hybrid spokeswoman Susan Garavaglia.

She said that the technology replaces a conventional automatic system with an electrically variable transmission that uses two electric motors to provide twin hybrid drive modes — one for city driving, the other for motorways.

The motors are coupled to two gearsets to provide a greater range of power and control than is possible with single mode hybrids. Garavaglia claimed that the clever design of the gearing used to amplify the power from the electric motors means that the system can also use smaller motors than those used in single-mode systems. She added that the system is designed to fit within the approximate space of a conventional automatic transmission.

In city traffic, one motor acts as a generator, while the other provides drive power. In this mode the system can operate with either the engine, the motor, or any combination of the two. In the second mode both motors can switch between operating in motoring or generating modes depending upon the vehicle speed.

GM is set to debut the system on its 2007 Chevrolet Tahoe SUV, while DaimlerChrysler will launch the technology on its Dodge Durango light truck.

These vehicles, which currently consume exceptionally high volumes of fuel, are expected to enjoy savings of around 25 per cent. The two-mode system is also expected to improve the truck’s pulling-power. BMW is yet to reveal its plans.

While some industry analysts have suggested that the three companies are merely jumping on the bandwagon following the success of the Prius, Garavaglia denied that this is the case. She said that GM has been working on the core technology for a number of years and the company has a long-term commitment to hybrid drives.

‘Hybrids will become another way that we can offer customers fuel economy savings. Even after the introduction of hydrogen fuel cell vehicles, hybrids will be seen on the market for quite some time in the future.’