Mercedes-Benz has developed multi-concept cars with alternative propulsion, such as hybrid-electric, fully electric, and fuel-cell powertrains. At the 2007 Frankfurt motor show, Mercedes-Benz showed seven hybrid models, including the F700 concept car, powered by a hybrid-electric drivetrain featuring the DiesOtto engine.[61] In 2009, Mercedes-Benz displayed three BlueZERO concepts at the North American International Auto Show.