Performance of CI Engines Fuelled with Biodiesel Blends during Transient Operations

In this study the performance characteristics of a CI engine which is fuelled with biodiesel blends during transient conditions were investigated experimentally based on a four-cylinder, four-stroke, direct injection (DI) and turbocharged diesel engine. Different blends from biodiesel and standard diesel (0B, 20B and 100B, 20B means 20% biodiesel and 80% diesel) were tested in the engine operating under two typical transient conditions: the speed varying event and the load varying event. During the experiment, in-cylinder pressure, fuel flow rate and exhaust temperature were measured and detail analyses were carried out on the measured parameters. The analysis conducted on the fuel flow rate shows that the fuel consumption of the engine running with 100B is higher than that of diesel by 16% and 14% for the acceleration and deceleration transient operations respectively. These values increased to 17% and 15% for positive and negative load changes operations. In acceleration and deceleration conditions, the exhaust temperature of engine running with diesel is 2% lower than that of using biodiesel blends. During load transients, the engine running with neat biodiesel produces 7% higher exhaust gas temperature than that of running with diesel. The performance values of 20B blends is in between that of the diesel and neat biodiesel for all key parameters.