An Experimental Study of Optimization of Biodiesel Synthesis from Waste Cooking Oil and Effect of the Combustion Duration on Engine Performance

The use of waste cooking oil (WCO) as a reagent for biodiesel synthesis ensures their transformation from harmful products into beneficial ones. The possibility of safe use as pure fuels or mixtures with diesel is a promoting and an environmental friendly alternative. This strategy is very encouraging especially for countries which have not enough space to produce vegetable oils. However, the researches in this field (WCO biodiesels) are still rare. In this work, we have synthesized biodiesel from WCO using the transesterification technique, then experimental investigations have been carried out on a four cylinder-direct injection diesel, engine equipped with a turbocharger on a test bench, according to the International noun ISO 27.020. In a first time, effects of different blends of methyl-ester/diesel in different proportions (B00, B10, B20 and B30) on engine behavior were studied and compared with petroleum diesel. In a second time, B20 blend was investigated but with variation of injection timing compared to original settings (as set by the engine manufacturer), on the same engine and following the same testing procedure. Experimental results showed that engine performance decreased with increasing amount of methyl ester in the fuel mixture. Moreover, it is found that advanced injecting B20 fuel by 2 crank angle degrees compared to that of the original injection timing, gives better performance without penalty on pollutant emissions (smoke opacity). The use of B20 accompanied with the advanced injection timing lead to a significant power increase (up to 4%) as well as an increase in torque (up to 2.8%) on conventional diesel engines compared to diesel. Emissions such as Smoke opacity remained close to the original values (without variation of injection timing).