Accelerated Wear Testing of the Effects of Biodiesel on Piston Ring to Cylinder Wall Wear

This paper will review the development and results of an accelerated test established to study the engine wear observed in some engines fueled with Biodiesel Fuel (BDF). BDF is a clean burning alternative fuel that can be produced from domestic renewable resources. Its basic composition is of multiple Fatty Acid Methyl Esters (FAME) (1). These fatty acid methyl esters are an excellent source of energy but have different physical properties as compared to petroleum based diesel fuel. The differences in physical properties can lead to increased dilution of BDF in the engine oil. Petroleum based diesel fuel (PDF) has increased volatility when compared to BDF, which allows the fuel to evaporate from the engine oil through the crankcase ventilation system. The lower volatility of BDF results in a lower evaporation rate and thus comparatively higher levels of BDF dilution in the oil. This higher dilution level alters the oil's viscosity and interacts with the oil's additives. This paper describes the development of a reciprocating test rig that would replicate the operating conditions of a diesel engine by simulating piston rings against cylinder liner wear. The main objective of the rig is to perform accelerated wear tests at elevated temperatures with different dilution levels of B100 BDF in engine oil (petroleum based). The wear results, wear mechanisms, and the quantification of surface failure from the testing method are reviewed.