Diesel Fuel Quality Effects on Exhaust Emissions 881649
Diesel cars have gained a remarkable market share in Europe and other areas. The relationship between fuel properties, engine design and environmental effects is therefore of considerable interest and this paper reports the results of an investigation employing a seven fuel matrix with two versions of one engine model.
Specially selected diesel fuels were used to quantify the influence of fuel properties on exhaust emissions and cold start behaviour of passenger car compression ignition engines. Both legally regulated emissions (CO, HC, NOx and particulates) and other selected species were measured.
These investigations were based on the engine design enjoying the highest worldwide production for passenger car diesels, the Volkswagen 1.6 litre 4-cylinder engine. This swirl chamber engine was tested in both its naturally aspirated and turbocharged versions.
The test fuel parameters varied were: density, cetane number, aromatic content and distillation characteristics. Most of the fuels were blended from conventional refinery components so that some interdependence between fuel characteristics is inevitable.
In addition to the exhaust emissions tests, cold start and cold running behaviour were also evaluated.
The results reported in this paper indicate that fuel properties do have some influence on emissions performance. However, it has to be emphasized that this influence is small. The results presented show that a 1983 model year European build engine continues to meet the latest ECE 15-05 proposed emissions limits except when grossly over-fuelled by a fuel of 0.881 kg/m3 density. For comparison, a very low cetane number synthetic crude sourced diesel fuel gave similar or better results than many of the higher cetane number fuels in the test series.