Analysis of unregulated emissions from an off-road diesel engine during realistic work operations

Emissions from vehicle diesel engines constitute a considerable share of anthropogenic emissions of pollutants, including many non-regulated compounds such as aromatic hydrocarbons and alkenes. One way to reduce these emissions might be to use fuels with low concentrations of aromatic hydrocarbons, such as Fischer–Tropsch (F–T) diesels. Therefore this study compared Swedish Environmental Class 1 diesel (EC1) with the F–T diesel fuel Ecopar™ in terms of emissions under varied conditions (steady state, controlled transients and realistic work operations) in order to identify factors influencing emissions in actual operation. Using F–T diesel reduced emissions of aromatic hydrocarbons, but not alkenes. Emissions were equally dependent on work operation character (load, engine speed, occurrence of transients) for both fuels. There were indications that the emissions originated from unburnt fuel, rather than from combustion products. ► Investigated unregulated emissions from standard diesel and Fischer–Tropsch fuel. ► Observed at steady state and during transients and work operations. ► Aromatics lowest with Fischer–Tropsch. ► Transients had a similar impact with both fuels. ► Emission trends during transients similar to hydrocarbon emission trends.