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The durability and performance of diesel fuel injection equipment in actual use continues to be a concern for the manufacturers of diesel powered equipment, diesel fuel injection equipment suppliers and diesel fuel suppliers This concern has been caused by recent changes to both the equipment and the diesel fuel driven by environmental legislation The term “lubricity” has become commonly used to describe the ability of a diesel fuel to prevent or minimise wear in diesel fuel injection equipment Of particular interest are distributor and rotary type fuel injection pumps that rely totally on the fuel for lubrication These pump types are commonly used in light and medium duty diesel engines Earlier work has shown that fuels with good low temperature properties have inherently poorer lubricity performance than summer quality diesel fuels (1, 2)* Due to the need for such fuels in Canada we have been investigating the lubricity performance of winter diesel fuels for a number of years Most recently we have studied the lubricity performance of various fuels and additives in rotary type pumps and related these results to the test fuel properties, including lubricity as measured in a number of current lab bench tests

A total of 54 Canadian Diesel Fuels were sampled in the winter of 1994/95. Both Regular and Low Sulfur (less than 500 ppm by mass sulfur) fuels were sampled. All the fuels were obtained directly from refineries and were intended for commercial sale. The fuel samples were evaluated for lubricity, as measured by the High Frequency Reciprocating Rig (HFRR) at 25 °C, and by the Scuffing load BOCLE (SLBOCLE) as developed by the Southwest Research Institute. Various relevant inspection properties were also determined. Total aromatic content and aromatic type (mono, di or poly) of the samples was also determined by High Pressure Liquid Chromatography (HPLC). The lubricity evaluations obtained are discussed, and compared to the other parameters obtained.

In the last few years there have been sporadic complaints regarding field failures of diesel fuel injection equipment. Upon investigation these complaints have been associated with: i) rotary or distributor type pumps as used in light and medium duty diesel engines, and ii) the use of “winter” grade diesel fuels or diesel fuels that have been altered to meet the requirements of environmental regulations. Rotary and distributor type diesel fuel pumps rely totally on the fuel for lubrication. The fuel's ability to prevent or minimize wear in these types of pumps is important. This ability has recently been referred to as the fuel's “lubricity”. Shell Canada has been investigating this issue for the past few years. Recently we have investigated the “lubricity” performance of various diesel fuels using two diesel fuel pump endurance rigs. One rig consists of two rotary type pumps, the other two distributor type pumps.