Low viscosity lubricant contribution to reduce life cycle CO₂ emissions on passenger vehicle

This paper presents a study of the environmental performance impact of a comprehensive set of conventional viscosity lubricants and latest low viscosity lubricants, considering the use for average fuel economy passenger vehicle (118.1 g-CO₂/km in 2016). The vehicle was assumed to be equipped with either automatic transmission (AT) or contentiously variable transmission (CVT) with a lifetime mileage of 150 000 km. Engine oil, transmission fluid as well as oil filter were identified as requiring servicing (replacement) in the maintenance phase. It was found that the analyzed engine oil, AT fluid and CVT fluid with different formulations show almost identical CO₂ emissions per weight from the lubricants production, and the contribution of the oil filters and the transmission fluids to CO₂ emissions in the maintenance phase accounts for over 20%. The latest low viscosity lubricants improved vehicle fuel economy by up to 4.0% compared to conventional viscosity lubricants. As a consequence, latest lubricants have the potential to save the vehicle life cycle CO₂ emissions by up to 630 kg-CO₂ even when subtracting the produced CO₂ emissions in the maintenance phase, with comparison of conventional viscosity lubricants.