Effect of injection timing on combustion, emission and performance characteristics of safflower methyl ester in CI engine

Abstract

Biodiesel, as a renewable fuel, holds great promise, yet its high viscosity presents significant challenges when used in diesel engines. To address these challenges, this study delved into the effects of injection timing on the combustion, emissions, and performance of safflower methyl ester (SAME) in a compression ignition (CI) engine. The experimentation involved testing at three different injection timings: the standard 23° BTDC, advanced 27° BTDC, and retarded 19° BTDC. The results yielded valuable insights. Retarded injection timing notably extended ignition delay by 18 % and reduced the heat release rate by 5 % compared to the standard timing, leading to a substantial decrease in NOx emissions by up to 28 %, a 25 % reduction in CO emissions, and a 5 % decrease in smoke opacity. However, it came at the cost of a 10 % reduction in brake thermal efficiency. Conversely, advanced timing increased NOx emissions by 4 % but concurrently lowered smoke opacity by 3 %. This study underscores the critical importance of optimizing injection timing to balance emissions and performance, mainly when dealing with high-viscosity biodiesels like SAME in diesel engines. The results also highlight the potential of SAME as a viable alternative fuel source, provided that injection timing is judiciously managed to account for its unique viscosity and combustion characteristics. In the quest for sustainable energy solutions, such research is pivotal in harnessing the full potential of biodiesel and advancing its integration into the transportation sector.