Effects of Bio-Alcohol Fuel Blends on the Aging of Engine Lubricating Oil 2018-01-1746

Bio-alcohol fuel blends will gain in importance for future mobility. The driving force is the necessary reduction of greenhouse gases and harmful exhaust gas components. The new fuels offer advantages in engine combustion and resulting exhaust emissions because of the short-chained molecules and resulting low C/H ratio as well as the higher oxygen content. The aim of the project is a systematic analysis and evaluation of the effects of two bio-alcohol blends on the lubrication oil ageing of a gasoline-driven Euro 6 passenger car engine. For this reason a test engine was operated with three different fuels: a fossil gasoline (E0) without bio-alcohol components, a blend containing 30% vol ethanol (E30) and a blend containing 15% vol methanol (M15). During the engine test, gas of the cylinder charge and blow-by has been sampled and analyzed by ion chromatography regarding short-chained organic and inorganic acids. Based on these results the acid entries in lubricating oil were determined. In addition to the acid entries the entry of fuel into the lubricating oil were determined and compared for different engine operation points and test fuels. The causes of the fuel entries are discussed, based on the different fuel compositions and the resulting properties of bio-alcohol fuel blends. The results of the project provide detailed insights in the influence of the bio-alcohol fuel blends lubricity and aging of engine lubricating oil. This knowledge is prerequisite for a successful introduction of fuels with higher amounts of bio-alcohol in the market to meet the target for carbon dioxide reduction in the future mobility sector.