The influence of fuel sulphur content on the exhaust emissions of sixteen European vehicles was assessed as part of the EUROPEAN PROGRAMME on EMISSIONS, FUELS and ENGINE TECHNOLOGIES (EPEFE). This programme was jointly carried out by the European automotive (ACEA) and the oil (EUROPIA) industries.
By reducing fuel sulphur content from the highest to the lowest sulphur levels tested, 382 ppm to 18 ppm, fleet average emissions in term of CO, HC, and NOx were reduced by approximately 10%.
The response was generally linear, allowing good predictive models to be developed.
The magnitude of the sulphur effects depended strongly on vehicle technology used. In particular, palladium (Pd) based catalyst vehicles were found to be more sensitive than vehicles fitted with platinum/rhodium (Pt/Rh) only based catalysts.
Reducing sulphur from 382 to 18ppm did not affect the relative distribution of exhaust hydrocarbon species, except benzene and alkanes, especially methane and ethane, which were also shown to reduce with reduced sulphur content.