Impact of exhaust gas recirculation on the performance, emission, and combustion features of a diesel engine using diesel, <scp><i>n</i></scp>‐butanol, and waste cooking vegetable oil blends

Abstract The present study highlights the impact of exhaust gas recirculation (EGR) on the performance, emissions, and combustion characteristics of a diesel engine using blends of diesel, n ‐butanol, and waste‐cooking vegetable oil (WCVO). The experiments are performed in a single‐cylinder, 4‐stroke water‐cooled diesel engine under variable engine loads (0, 4, 8, 12, and 16 N) with a constant speed of 1500 rpm (compression ratio of 18:1). Three WCVOs (Ground nut, Palm, and Sunflower) in volumes of 20% each along with n ‐butanol at 10% and diesel at 70% are considered for the analysis. The diesel engine adjusts the EGR at 15% and 25%. For these cases, performance features such as brake thermal efficiency (BTE), brake‐specific fuel consumption, brake‐specific energy consumption, and exhaust gas temperature are evaluated. The BTE was observed to decrease with the WCVO blends due to their higher oxygen content and lower calorific value. The BTE value is also increased for the Palm WCVO at the 15% EGR with the increase in engine load. The emission parameters like nitrogen oxides (NOx), carbon monoxide, carbon dioxide, oxygen, and smoke opacity are also tracked, and it was found that the NOx and particulate matter inside the engine cylinder are reduced using the EGR. For all loads, the Sunflower (20%) with 15% EGR reduces the NOx by 5%–10% compared to diesel. The combustion parameters, like cylinder pressure and heat release rate, are also analyzed for all fuel blends.