UTILIZATION OF BIOGAS WITH DIFFERENT PILOT FUELS IN DUAL FUEL MODE IN DIESSEL ENGINE

Abstract

Industrial dependence on energy and international conflicts has triggered the fuel prices to new highs. As a result, new alternative fuels must be explored that have no or very less harmful emissions without the compromise of the efficiency. One such fuel that can be converted for use in internal combustion engines is biogas. In this experimental study, a Direct Injection Compression Ignition (DICI) engine is converted into a dual-fuel engine that runs on biogas as primary fuel and various fuel blends as the pilot fuel. It will achieve the goal of lower exhaust emissions although the thermal efficiency remains nearby same. Diesel, biodiesel, alcohol and their blends are used as the pilot fuel, whereas biogas-air mixture is injected through intake manifold. Engine air intake system is upgraded to allow the combination of air and biogas to mix thoroughly before being fed to the cylinder. The engine performance and emission characteristics are measured and compared with conventional diesel engine. The findings of this investigation revealed that a DICI engine can efficiently be converted into a dual-fuel engine that runs on both diesel and biogas. Brake thermal efficiency decreases from 33.23% (in diesel mode) to 18.86% in dual fuel mode due to the lower calorific value of biogas compared to diesel. Whereas, the exhaust emissions like HC, CO, and CO2 are also measured and found a increment in their percentage but for NOx percentage was reduced r. Further, the results shows that the ratio 80:20 (i.e., 20% SBDO and 80% biogas) can be used in diesel engine with a very little reduction in engine performance; thus, saving about 80% of the conventional diesel fuel. Therefore, the engine performance characteristics reveal that a considerable amount of diesel can be saved with addition of biogas in dual-fuel mode.