Performance optimization of Jatropha biodiesel engine using RSM

Abstract

The performance of diesel engine using biodiesel as fuel is significantly affected by several parameters including engine operating variables like load, speed and injection timing. The effect of the operating parameters is quite significant and their effect on engine performance has been widely studied by many researchers. In this work, the effects of load torque, engine speed and static injection timing, on the performance and emissions of diesel engine fueled with diesel and Jatropha biodiesel has been given. In the present investigation, the following output indicators have been considered: Brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), unburned hydrocarbons (HC), oxides of nitrogen (NOx) and smoke density. In the present article, statistical modeling technique namely Response Surface Methodology (RSM) is employed to determine the relationship between output and input variables. An analysis of variance (ANOVA) is carried out using the Design-Expert version 6.0.8, for each of the response variables separately, in order to test significance of the relationship obtained between the response and input parameters (i.e. model) and its suitability. After obtaining the validated output-input parameters relationships, these model equations are used to optimize the input parameter values for the required objective of the output (i.e. minimizing the fuel consumption and emissions and maximizing the thermal efficiency etc.). Finally, injection timing, load torque and engine speed levels are optimized for better performance and lower emissions for Jatropha biodiesel engine. In the present work, multi objective optimization principle using the method of objective weighting has been employed. The optimal solution is obtained using second-order polynomial form of response equations and they were optimized for better fuel economy and performance and lower emissions.