An Experimental Study of EMS Control Parameter Optimization for the Use of Biodiesel Blend Fuel

Use of biodiesel fuel (or its blends with petroleum diesel) has become of worldwide interest and seriously investigated for its merits and demerits. This study focused on the effects of using BD30 (a blend of 30% soybean methylester biodiesel and 70% ultra low sulfur diesel fuel) in the aspects of exhaust emissions and combustion characteristics in a modern SUV, equipped with 3.0 liter CRDI engine. In general, it has been reported that the use of biodiesel could be beneficial for the emissions of HC, CO and PM at a certain degree of the deteriorations in NOx level and fuel economy. However, our current tests with BD30 by driving on the European emission cycle resulted in an increased HC and CO emission level, compared to the standard diesel fuel. After all, it can be suggested that, in order to the use of biodiesel fuel and to maintain the equivalent emission level with diesel, an improved catalytic converter might be required or the increased HC and CO should be traded with the reduced PM by modifying control parameters in EMS(engine management system). In this research, the experiments with BD30 have been performed to observe and analyze the changes of the resultant emissions by manipulating several major control parameters from the diesel EMS basis (such as air mass flow rate, injection timing and injection pressure). Finally, an optimized control parameter set of the EMS has been proposed, instead of reinforcing the catalyst and thus in order not to increase the manufacturing costs.