Ever increasing demand and consequent rise in prices of petroleum products, stringent emission standards, the exponential depletion rate of fossil fuel reserves and escalation in the number of vehicles on the road have forced us to look for alternatives to meet the present and future demands of the energy requirements. Biodiesel production from waste oils and fats are cost effective methods which prevent the environmental pollution by proper disposal techniques. In this study, biodiesel was prepared from the waste effect chicken fat using the two stage esterification process. The present investigation deals with the cold exhaust gas recirculation (EGR) with the flow rates of 10, 20, 30% on a four stroke, single cylinder, direct injection (DI) diesel engine fueled with waste chicken fat biodiesel blends to reduce the NOxemissions of the engine. Experimental results showed higher oxides of nitrogen emissions when fueled with waste chicken fat biodiesel without EGR and found reduced NOxemissions about 25% when operating with B20 fuel blend with 30% EGR. The EGR level was optimized as 20% based on the significant reduction in NOx emissions, minimum possible smoke, CO, HC emissions and comparable brake thermal efficiency.
