Diesel fuel lubricity testing revisited: Tests von Dieselkraftstoffschmierfähigkeit erneut betrachtet

Fuel is used as a lubricant in several engine components. Diesel fuel is known for its good lubrication properties, better than gasoline. These properties are examined in standard tests, as prescribed by ASTM. Good lubrication properties are designated as a good lubricity. Most commonly, fuel lubricity is tested using a standard type of tribometers, called HFRR (High Frequency Reciprocating Rigs), and BOCLE (Ball-on-Cylinder Lubricity Evaluators). Currently new diesel fuels are being tested in TU/e’s Combustion Technology lab. Lubricity is an important issue. It is required that their lubricity may not be worse than for a standard diesel fuel. Several engine contacts show a conformal geometry, while in all standard tests the test sample geometries are highly nonconformal. Consequently, testing fuels using ASTM test standards may lad to erroneous results. A Plint TE77 reciprocating tribometer was used to test a contact pair having a much higher conformity than standard equipment. A 50 mm diameter ball bearing ball slides against a flat hardened steel plate. Under these circumstances, the additivated diesel fuel showed less friction than standard diesel fuel. However, there is a wide scatter in the friction force results. More test data are needed to support the these results of better lubricity of the additivated diesel. This is a first and preliminary study. The test duration was too short to observe fuel wear behaviour