Improved fuel efficiency by lubricant design: a review

There is currently a strong focus on producing increasingly fuel-efficient vehicles, both to help meet CO2 emissions reductions targets arising from t he Kyoto Agreement on climate change, and, in certain countries, to avoid l arge government-imposed financial penalties. This paper reviews the role th at lubricants can play in reducing a vehicle's fuel consumption. The paper reviews the lubricant factors that affect fuel consumption. The paper also reviews a number of engine friction models, which help to give insight into the relative importance of the different engine components to total engine friction. The paper reviews how these models compare with results from the European and US passenger car standard fuel economy engine tests now in pl ace. The paper also reviews the issues surrounding engine durability with t he lower-viscosity fuel economy lubricants that are now being developed. Th e majority of the paper is concerned with fuel economy in passenger car veh icles, but there is also some discussion of the issues surrounding improved fuel economy in heavy-duty diesel trucks.