Ternary gasoline – Pomegranate peel oil (PPO)- tertiary butyl alcohol (TBA) blend as an enabler to improve the spark-ignited engine performance and emissions

Abstract

This paper reported a research work that investigated the compatibility of using pomegranate peel oil (PPO) as a substitute for gasoline in a spark-ignition engine. Initially, fuel characterization was performed for the PPO biofuel, and a blend was prepared by blending PPO in gasoline at a ratio of 10:90 by volume. Then, fuel properties were measured for the gasoline, PPO, and its blend. Subsequently, engine experiments were conducted for the blend at different load conditions with constant speed, and the performance, combustion, and emission results of the blend were compared with that of sole gasoline. By analyzing the results, it was found that the brake thermal efficiency of the 10% PPO blended gasoline was reduced by 1.2%, 0.6%, and 1%, at low load, mid load, and full load, respectively, when compared to sole gasoline. Whereas the HC and CO emission of the blend was higher by about 11.7% and 8.3%, respectively, at full load, when compared to that of gasoline. With an intent to improve the performance of the PPO blend, tertiary butyl alcohol (TBA) was blended with the 10% PPO blended gasoline in the volumetric proportion of 5%, 10%, and 15% to form ternary blends. The experimental study revealed that the performance of the PPO blend was enhanced significantly with increasing TBA proportion in the blend. The PPO blend with 15% TBA exhibited the highest BTE of 25.1%, which was 1.6% higher than gasoline at full load. The same blend resulted in the HC and CO emissions that were 9.2% and 9.6% lesser than gasoline, respectively, whereas NO emission was 7.6% higher than gasoline, at full load condition. The combustion analysis revealed that the start of combustion was delayed, with peak pressure and heat release rate being the maximum for ternary blends. From this investigation, it can be concluded that the sole gasoline can be replaced by the ternary blend as fuel for SI engine operation without requiring any major engine modification.