Effect of Diesel Properties on Emissions and Fuel Consumption from Euro 4, 5 and 6 European Passenger Cars

Certain diesel fuel specification properties are considered to be environmental parameters according to the European Fuels Quality Directive (FQD, 2009/EC/30) and previous regulations. These limits included in the EN 590 specification were derived from the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) which was carried out in the 1990’s on diesel vehicles meeting Euro 2 emissions standards. These limits could potentially constrain FAME blending levels higher than 7% v/v. In addition, no significant work has been conducted since to investigate whether relaxing these limits would give rise to performance or emissions debits or fuel consumption benefits in more modern vehicles. The objective of this test programme was to evaluate the impact of specific diesel properties on emissions and fuel consumption in Euro 4, Euro 5 and Euro 6 light-duty diesel vehicle technologies. The tests were conducted in two driving cycles, the New European Driving Cycle (NEDC) and the Worldwide harmonised Light duty Test Cycle (WLTC), which is considered closer to real driving and is going to be the new type approval test in the near future. Apart from FAME content, properties studied were Poly-Aromatic Hydrocarbon (PAH) content, density, and cetane number. Results of emissions testing will be presented and discussed including effects of the above fuel properties on particulates, NOx emissions, fuel consumption, energy consumption and CO₂ emissions.