Fuel for thought: Powertrain efficiencies of British vehicles

Improving vehicle fuel efficiency is critical to tackle climate change. This requires understanding the drivers of efficiency improvements in both the powertrain and vehicle body. This paper uses US coast down data to estimate the powertrain efficiencies of new British models in 2010 showing the differences between available models for the first time. Powertrain efficiency decreases with increasing engine capacity, and increases in vehicle mass are found to be more detrimental to vehicle efficiency than aerodynamic area. Finally, it is concluded that the difference between diesel and petrol powertrain efficiency grows with increasing vehicle size