Emissions Performance of Pure Vegetable Oil in Two European Light Duty Vehicles

This programme involved the testing of two Euro II compliant diesel vehicles over the current European legislated drive cycle. The aim of the programme was to determine and compare the emissions of 100% virgin vegetable oil (VVO100) and a baseline UK marketplace Ultra Low Sulphur (ULSD) diesel fuel. A splash blend of 5% rapeseed methyl ester in ULSD (RME5) was also evaluated.

Results of tests on RME5 showed that generally the effects on emissions compared to ULSD were small for regulated and most unregulated emissions. There was some evidence of a PM10 benefit for RME5 fuel.

VVO100 showed large increases in HC (up to 250%) and CO emissions in both vehicles, as well as increases in polycyclic aromatic hydrocarbons (PAH), compared to ULSD. Effects on NOx and particulate were vehicle - specific. Emissions evidence and information from published studies suggests that many of the emission effects seen on VVO100 fuel were associated primarily with poor atomisation due to the high viscosity/molecular weight of the fuel.