Base Oil Effects on Emissions and Fuel Economy in a Heavy-Duty Vehicle Over the European Transient Cycle (ETC)

The emissions and fuel economy performance of a series of advanced SAE 5W-30 engine oils were evaluated in a 12-litre heavy-duty diesel truck driven over the European Transient Cycle (ETC) under both cold and hot start conditions. The SAE 5W-30 oils were formulated with polyalphaolefin (PAO) and VHVI mineral base oils with the same additive package and a comparison made with SAE 15W-40 lubricants containing standard mineral oil. Results compare the performance of the oils over the urban, rural and motorway portions of the ETC. A significant reduction in particulate mass emissions was seen for the PAO containing lubricants under the different driving conditions when compared to the VHVI and standard mineral oil lubricants. An average fuel economy benefit of 2% was demonstrated for SAE 5W-30 viscosity grade lubricants over the SAE 15W-40 lubricants. The results show that lubricants formulated with PAO can be used to reduce engine-out particulate emissions and thus contribute to a technology solution that enables heavy-duty diesel vehicles to meet future stringent emission requirements.