Abstract
•Utility from the exhaust gas energy by preheating and re-exhausting into engine.•Design a heat exchanger to take advantage of the exhaust heat to preheat the biodiesel fuel.•Applying of EGR system to reduce NOx emission.•Improve engine performance and reduce the emitted pollutants from the engine.
This investigation study is concerned with the effect of exhaust gas recirculation(EGR) on diesel engine performance and emission fuelled with preheated biodiesel fuel. A single cylinder, air cooled, diesel engine was used and equipped with measurement instrumentations to accomplish the purpose of investigation. This work seeks to determine the influence of EGR on engine performance characteristics and emissions. Biodiesel fuel was preheated before entering the engine through a heat exchanger. The preconditions of the engine experiments were constant in all times to ensure the accurateness of the practical results. EGR rates were changed up to 25%. Biodiesel fuel was preheated at different temperatures up to70 °C. Therefore the main goal of this investigation study can be considered that dual utility of exhaust energy to improve diesel engine performance and emissions fuelled with biodiesel. The results show a slight improvement in the performance of the engine. There is a clear reduction in pollutants emitted from engine fuelled with biodiesel, especially NOx emission, with a decrease rate of 22.2% at 25% EGR (baseline: biodiesel @ 0% EGR and 30 °C preheating), while the reduction rate of CO and HC is 8.16% and 6.13% at 0% EGR respectively.