What started as a very promising collaboration between General Motors, DaimlerChrysler and BMW is looking increasingly like a technological dead end. The two-mode hybrid system originally developed by General Motors' former Allison division for transit buses was to be adapted to light-duty applications by the three (later four after the DCX divorce) automakers. The system, which was designed to provide efficiency benefits at highway speeds as well as in urban stop and go driving, is mechanically complex and very expensive to build.
GM has applied it to many of its full size trucks and SUVs. However, the first Chrysler SUV application was short-lived and Chrysler's only other announced plan is the Ram pickups in 2010.
The Germans, meanwhile, created a repackaged version of the two-mode transmission that will appear in the Mercedes ML450 and BMW X6 later this year. Those will likely be the only applications of the system for the German brands. Future hybrids are likely to use a cheaper, more modular system – possibly derived from the mild hybrid system developed by Daimler and BMW. Both automakers are also looking at other technologies, including battery electrics, as an alternative. The Two-Mode alliance will likely be dissolved by the end of this year.
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[Source: Automotive News - sub. req'd]