Effect of Fuel Injection Pressure on Performance and Emission Characteristics of a Compression Ignition Direct Injection Engine Fuelled With Waste Cooking Oil Biodiesel Mixture

In the recent years, biodiesel has become a promising solution to the rapid depletion of the fossil fuel reserves as well as to the alarming amount of discharged pollutants. But inherent properties such as low volatility, high density and high viscosity have been pointed at for inducing most of its drawbacks. Many studies have been undertaken in order to inhibit these deficiencies. Hence, the aim of this study is to investigate the effect of varying injection pressure on performance and emission characteristics of a four-cylinder, four-stroke, compression ignition direct injection engine fuelled with mineral diesel fuel and 20%, 40% and 60% waste cooking oil biodiesel blends (B20, B40 and B60). To that end, five injection pressures were tested: the original 200 bar, 220 bar, 240 bar, 260 bar and 280 bar. Experiments were conducted in accordance with the procedure dictated by DIN 70020. This study revealed that implementing the injection pressure up to 240 bar induces significant improvement in the performance characteristics for all tested fuels to varying degrees. The B20, under this optimized injection pressure was found to offer the best performances characteristics. Increasing injection pressure has proven its worth within a restricted limit. Indeed, for 260 bar and 280 bar, for all tested fuels, performance and smoke level characteristics were found to be dwindling.