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In the last few years, particularly since the introduction of Low Sulfur Diesel fuel (i.e. containing less than 500 ppm Sulfur), there have been sporadic complaints regarding field failures of rotary or distributor type fuel injection pumps as used in light and medium duty diesel engines. These failures have been typically associated with the use of either “winter” grade diesel fuel or diesel fuels that have been significantly altered due to environmental legislation (i.e. such as has been mandated in Sweden). Shell Canada has investigated the lubricity of such fuels where “good” lubricity is defined as the ability of a fuel to prevent or minimize wear in diesel fuel injection equipment. Evaluation methods included: actual over the road vehicle tests Tests using purpose built fuel pump endurance rigs Lab bench tests such as ASTM D5001,Scuffing versions of this test and the High Frequency Reciprocating Rig (HFRR) Test.

This program examined the PAH emissions from two diesel engines representing state-of-the-art technology. One heavy-duty engine, a DDC Series 60, used in highway trucks, and one medium-duty engine, Navistar DTA-466, used in pick-up and delivery type vehicles. The medium-duty engine was tested for engine out emissions and with two different sized exhaust oxidation catalysts. Both of the catalysts were composed of a ceramic monolith coated with a palladium type catalyst. Both engines were tested according to the US EPA transient emissions test on a series of diesel fuels blended with varying aromatics and PAH contents to determine the impact of fuel quality on emissions. All diesel fuels had a low sulphur content (<0.05%) to minimize the formation of sulphate. The particulate matter was collected on teflon-coated filters, backed up with polyurethane foam filters to capture the vapour phase PAH.