Mercedes-Benz might unveil up to 18 different eco-friendly vehicles at September’s Frankfurt Motor Show, including a range of diesels, hybrids, Bluetec-diesels and fuel-cell vehicles. The star of the Mercedes’ showcase will be a new Bluetec-diesel model that will feature a mild-hybrid system, a car that is expected to hit the market by the end of the decade.

Other green models will include an ultra-efficient diesel C-class that’s due to hit the market by 2011 and is reported to sip less than five liters of fuel per 100km, while emitting less than 130g of carbon-dioxide per km. Auto Motor und Sport is also reporting that Mercedes will present versions of its E and S-class sedans that will meet Europe’s future Euro 6 emissions standards that are expected to roll in by 2014.

Finally, Mercedes may also preview a future hydrogen fuel-cell vehicle based on its B-class, which is rumored to be produced in a limited batch of 150 cars starting in 2010.