How hybrid-electric vehicles are different from conventional vehicles: the effect of weight and power on fuel consumption

摘要

An increasingly diverse set of hybrid-electric vehicles (HEVs) is now available in North America. The recent generation of HEVs have higher fuel consumption, are heavier, and are significantly more powerful than the first generation of HEVs. We compare HEVs for sale in the United States in 2007 to equivalent conventional vehicles and determine how vehicle weight and system power affects fuel consumption within each vehicle set. We find that heavier and more powerful hybrid-electric vehicles are eroding the fuel consumption benefit of this technology. Nonetheless, the weight penalty for fuel consumption in HEVs is significantly lower than in equivalent conventional internal combustion engine vehicles (ICEVs). A 100?kg change in vehicle weight increases fuel consumption by 0.7?l/100?km in ICEVs compared with 0.4?l/100?km in HEVs. When the HEVs are compared with their ICEV counterparts in an equivalence model that differentiates between cars and sports-utility vehicles, the average fuel consumption benefit was 2.7?l/100?km. This analysis further reveals that a HEV which is 100?kg heavier than an identical ICEV would have a fuel consumption penalty of 0.15?l/100?km. Likewise, an increase in the HEV's power by 10?kW results in a fuel consumption penalty of 0.27?l/100?km.