Mercedes-Benz is showing-off a diesel hybrid concept car at the 2005 Tokyo Motor Show. The S320 BLUETEC HYBRID uses a "mild-hybrid" to improve power in the full-size luxury sedan while getting approximately 30.6 miles per gallon of diesel burned. Meanwhile, the gasoline-powered 2006 Mercedes-Benz S350 sedan gets a combined 20 m.p.g. (17 city / 25 highway).
In addition to gains in acceleration and efficiency, the concept car uses Selective Catalytic Reduction (SCR) to decrease nitrogen oxide output and a particulate filter to keep emissions low - just like the Japanese regulations require. It's not clear if the system will be made available in the United States, but Mercedes Chairman Dr. Dieter Zetsche said "In terms of drive systems we are following a clear strategy which has three areas of emphasis: in parallel with further improvements to our petrol and diesel engines, we are considering our own mild-hybrid systems such as the BLUETEC HYBRID. In addition, we are working on full-hybrid systems together with our partners General Motors and BMW. We regard hybrid systems as an important step on the road towards emission-free automotive drive systems based on the fuel cell."