Optimization of Injection System Parameters and Exhaust Gas Recirculation for Jatropha Biodiesel Fuel in Diesel Engine Using Taguchi Method

An experimental investigation and Taguchi optimization analysis were carried out to optimize Jatropha biodiesel engine parameters for lower fuel consumption and exhaust emissions. The engine parameters considered for optimization were injection timing, injector opening pressure, nozzle configuration, nozzle tip protrusion, percentage of exhaust gas recirculation, fuel type, brake mean effective pressure (BMEP), and speed. Taguchi's signal-to-noise ratio approach was applied to obtain an optimal level setting of these parameters. From the experimental results and further analysis it is concluded that under 95% confidence interval a nozzle configuration of 5x0.18, tip protrusion of 3.5mm, exhaust gas recirculation of 0%, BMEP of 3.2bar, and speed of 1,800rpm with Jatropha biodiesel fuel gave the minimum carbon monoxide (CO) and unburned hydrocarbon (HC) emissions, whereas the lowest nitric oxide (NO) emissions were obtained with an injection timing of 350 crank angle degrees (CAD), nozzle configuration of 4x0.25, exhaust gas recirculation of 20%, BMEP of 1.6bar, and speed of 1,800rpm. However, the lowest brake specific fuel consumption (BSFC) was obtained with a nozzle configuration of 4x0.18, BMEP of 4.8bar, and speed of 1,800rpm with diesel fuel. The injector opening pressure with a range of 240-260bar had no significant effect on BSFC, CO, HC, NO, and smoke reductions. For the optimal engine parameter settings, the observed percentage reductions in BSFC, CO, HC, NO, and smoke emissions were 4.3, 50, 11, 10.2, and 3.45%, respectively. (C) 2013 American Society of Civil Engineers.