Experimental investigation on diesel engine performance, combustion, and emissions characteristics with Tucuma and Ungurahui biodiesel blends

The study conducted an experimental investigation of diesel engine performance, emissions, and combustion characteristics using Tucuma and Ungurahui biodiesel blends. Higher yield (greater than 99.4%), lower viscosity than diesel, and higher cetane number of these fuels have motivated a comprehensive investigation of the effect of these fuels on diesel engines. Four blends were tested in the engine by keeping diesel as the benchmarking fuel. The engine was operated at full load conditions, and the results were investigated with respect to brake power (BP). Results indicate that biodiesel blends showed similar combustion behaviour to that of diesel. Next to diesel, TB10 and UB10 showed better brake thermal efficiency (BTE) and lower brake-specific fuel consumption (BSFC). Higher peak pressures and heat release rates (HRR) are observed for the TB10 compared to the diesel operation. Moreover, prolonged combustion was observed for the four biodiesel blends during the diffusion and late combustion phasing. With the increase in BP, slightly higher HC emissions are observed for all the blends except for TB10 compared to diesel. Similarly, a slight increase in CO emissions is also observed for all the blends at higher BP. Higher acid values of both fuels are the likely cause of increased HC and CO emissions at higher BP. NOx emissions are slightly higher for both fuels, among these UB10 has shown lower NOx than other blends. The study concludes that TB10 has demonstrated better performance (near diesel) and combustion rates (better than diesel); however, emissions like CO and NOx are slightly higher than others. The study recommends blending TB10 and UB10 with the alcohols, ethers, and nanoparticles as they can reduce NOx and CO emissions.