Effect of exhaust gas re-circulation on performance, emission and combustion characteristics of ethanol-fueled diesel engine

Abstract

Ethanol, as a fuel for compression ignition (CI) engine, has some advantages over diesel fuel, and these include the reduction of soot, carbon monoxide (CO) and unburned hydrocarbon (HC) emissions. However, there are few concerns about ignition properties, and emissions (especially the particulate and NOx). For minimizing the emissions from the ethanol-fueled compression ignition (EFCI) engine, the exhaust gas recirculation (EGR) technique is proposed. In this paper, the EGR technique is used where some amount of the exhaust gas is drawn off from the exhaust system, cooled, and redirected back into the cylinders. The experimental setup of the ethanol-fueled diesel engine (EFDE) with EGR is developed. Using the setup, the performance, emission, and combustion characteristics of EFDE in different scenarios of EGR (ethanol + coating, ethanol + coating+10% EGR, ethanol + coating+20% EGR) were carried out. We observe that the exhaust fills the combustion chamber; however, it is not involved in the combustion reaction that takes place in the cylinder due to its low oxygen content. Hence, the combustion process speed is reduced, with the result that the peak flame temperature in the combustion chamber is lowered. This dramatically affected the characteristics of the EFDE. The obtained results of EFDE scenarios were compared with the diesel scenario. Overall, it is observed that the variation in the %EGR rates has a significant impact on the performance, emission, and combustion characteristics of EFDE.