Heavy Duty Diesel Engine Fuel Economy: Lubricant Sensitivities

The fuel consumption of heavy duty diesel engines is of great importance to fleet operators, since fuel can contribute up to 30% of the operating costs. This paper discusses the differences between fuel economy oils for heavy duty diesel engines and passenger car engines.

A simple model is then presented showing how the reduced friction due to the use of fuel economy lubricants (both in the engine and the transmission) can lead to fuel consumption benefits. By including realistic losses due to air resistance and tyre rolling resistance, the model can predict fuel consumption benefits under different speed and load conditions that are in reasonable agreement with the benefits found in carefully controlled field trials.