Tradeoffs in ultra-efficient vehicle design: Lessons from the automotive X PRIZE

In 2010 over fifty advanced vehicle prototypes competed in the $10M Progressive Insurance Automotive X PRIZE competition for 100 MPGe vehicles. Battery electric, hybrid, plug-in hybrid and traditional ICE vehicles were all represented. The competing vehicles were rigorously tested for fuel economy, range, emissions, and other performance characteristics. This paper presents selected data with a view toward establishing relative merits of fuel economy and overall powertrain efficiency design strategies. Specific examples are used to illustrate the most effective fuel economy strategies; including powertrain selection, charging and regenerative braking strategies, and vehicle platform optimization. Based on this comparison, conclusions are drawn about the relative effectiveness of widely varying strategies for ultra-high-mileage design.