A hybrid version of the W221 Mercedes Benz S-Class will be unveiled at the 2007 Frankfurt Auto Show in September this year, making it Mercedes Benz’s first hybrid car. Unlike most hybrids which use a petrol-electric combination, the hybrid S-Class will combined a Bluetec diesel engine with a compact electric motor.

A previous concept called the Direct Hybrid concept used a 3.0 litre V6 diesel engine together with an electric motor, but sources reveal it is more likely the S-class hybrid will use a four-cylinder Bluetec diesel instead, likely a similiar engine to the 2.2 litre 4-pot found in the Mercedes Benz Vision C220 Bluetec concept. There is also another Bluetec turbodiesel in the Benz arsenal – the 4.2 V8 TDI Bluetec that was put into the Vision GL420 Concept.

There is no official name for the car at the moment, but some have begun to call it the Mercedes-Benz S-Class Bluetec-Hybrid.