July 9, 2008 - Carmakers are now racing to design more innovative bodies incorporating advanced aerodynamics and light, biodegradable plastic components. Guy Negre, a motor engineer and founder of MDI Enterprises, a company that studies new technologies and production concepts to reduce the environmental impact of carbon dioxide, invented a compressed-air engine in 1996. “Obviously, we are obliged to make changes to the design in relation to the requirements and specifics of new technologies,” Mr.