Effects of concentration and temperature on tribological properties of biodiesel

Abstract

For tribologists, continuing challenges in engine design include reduced emissions and increased operating temperatures. Regulating the sulfur content in diesel fuel is expected to reduce the lubricity of these fuels, which may result in increased wear and damage of fuel injection systems in diesel engines. However, the use of biodiesel improves lubricity and cetane number requirements, particularly in ultra-low sulfur petro-diesel. In this study, the effect of temperature on the tribological properties of palm biodiesel was investigated using a wear machine. Palm biodiesel was used as a lubricating additive to petro-diesel at six concentrations of 2%, 5%, 10%, 20%, 50%, and 100%, and these biodiesel blends were named as B2, B5, B10, B20, B50, and B100, respectively. The tribological experiments were performed using the ball-on-ring method. Tests were conducted at 30°C, 60°C, 90°C, and 120°C, under a normal load of 50 N for 2 h and at a speed of 500 r/min. The wear scar diameter and the worn surface of tribopairs were studied and analyzed. According to the wear experimental results, the addition of a small amount of palm biodiesel to petroleum diesel can bring about a considerable reduction in the wear and friction under boundary lubrication. Results show that friction and wear increase with increasing temperature.