regarding the information i said before please visit the website below from mercedes usa about the bluetech technology
http://microsites.mbusa.com/microsite/bluetec/index.jsp
secondly just an advice wikipedia is never a credible source of information because any one can upload whatever he wants same for the google. so better get info from the source.
bluetech is originally a technology for diesel engines.
by the way i have just checked the wikipedia to make sure if they mentioned it wrong but i found it also saying that blueTEC is for diesel engines and they said nothing about gasoline.
http://en.wikipedia.org/wiki/BlueTec
there it is mentioned that this technologe is designed to make the diesel engines more environmentally while maintaining the fuel economy.
there is also a lot of valuable links at the bottom of the wikipedia page if anyone is interested in more info and has the time