The Diesel-Hybrid Bandwagon Builds
In the ongoing search for the optimal combination of low emissions and high fuel economy, more automakers are looking toward diesel-electric hybrid powertrains as a potential solution. The latest to test diesel-hybrid systems are Mercedes-Benz and the U.S. Army.
The problem with diesel-electric hybrids is one of cost, particularly with ever-tighter emissions standards requiring the use of more expensive exhaust-control technology on diesels, which generally emit more pollutants than gasoline engines.
But since diesels generally are more efficient and provide better fuel economy, automakers and suppliers continue to push technology frontiers in an effort to bring the hardware costs down.
Mercedes-Benz said it will unveil a diesel-electric hybrid prototype of its Citaro articulated city bus later year. With the diesel engine acting as a generator to charge the roof-mounted lithium-ion batteries, the prototype bus runs in pure electric mode and has the potential to offer fuel-economy gains of as much as 30 percent. The company expects production to begin in 2009.
In the U.S., supplier Quantum Fuel Systems Technologies Worldwide said it has been awarded a contract by the U.S. Army to develop a diesel-electric hybrid version of its Aggressor alternative mobility vehicle (AMV).
The diesel-hybrid version follows the original fuel-cell hybrid Aggressor that was developed for the U.S. Army's Tank Automotive Research, Development and Engineering Center (TARDEC), National Automotive Center (NAC).
The diesel-electric AMV is intended to be a second-generation high-performance light-duty off-road vehicle for the Army. Quantum will develop and build pre-production prototypes for testing by various Army units. Targets include high-performance acceleration, extended range and exportable power. The Army said the AMV could be suitable for a variety of commercial uses, including homeland security, border patrol and park service operations.
