Effect of Fuel Properties on Emissions from Euro 4 and Euro 5 Diesel Passenger Cars

Abstract

The EN 590 specification allows up to 7% v/v FAME to be blended into conventional diesel fuel which can then be used in most light-duty diesel vehicles. It is anticipated that higher FAME levels may be needed in order to meet the 10% renewable energy target mandated by the Renewable Energy Directive (2009/EC/28). 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 up to Euro 3 emissions standards. These limits could potentially constrain FAME blending levels higher than 7% v/v. No significant work has been conducted to investigate whether relaxing these limits would give rise to efficiency or emissions debits or benefits. For this reason, Concawe was interested in studying the impact of these parameters in Euro 4+ vehicle technology.A test programme has been conducted to evaluate the impact of specific diesel properties on emissions on a Euro 5 light-duty diesel vehicle. Tests were also carried out in a Euro 4 vehicle to provide comparison with previous work. Properties studied were Poly-Aromatic Hydrocarbon (PAH) content, density, and cetane number. The Fatty Acid Methyl Ester (FAME) content was an additional variable in the study. Results of emissions testing will be presented and discussed including effects of the above fuel properties on particulates, NOx, CO2 and fuel consumption.