UC Davis Institute of Transportation Studies

Developments in hybrid-electric driveline technologies and hybrid vehicles using internal combustion engines (ICE) are studied and the effects of those developments on fuel economy are assessed. Characteristics of hybrid-electric vehicles comparable to conventional ICE vehicles are conceptualized for two types, a mild hybrid and a full hybrid. Simulations are used to determine the fuel economy; differences in economy for the ICE and hybrid vehicles are calculated. As expected, improvements are greater for full hybrids than mild hybrids, but the mild hybrid design has a lower breakeven fuel price. Results also indicate that the fuel economy potential of vehicles using the advanced lean-burn gasoline engines are close to those of vehicles using diesel engines.