Impact of 1-Hexanol/diesel blends on combustion, performance and emission characteristics of CRDI CI mini truck engine under the influence of EGR

Biofuels are the most promising sustainable and renewable alternative to diesel fuel. In the present renewable energy world, alcohols are gaining prime importance due to their nature of production and fuel properties. The present work aims to investigate the impact of 1-Hexanol and exhaust gas recirculation (10% and 20%) on engine characteristics of the common rail direct injection compression ignition engine. The experiment is carried out on a bench engine. The fraction of 1-Hexanol is varied from 10% to 40% in a step of 10% by volume. The results demonstrate that the use of 1-Hexanol/diesel blends lowers the cylinder pressure and mean gas temperature, which is 4.25% and 1.88% lower at 60% load for 40% 1-Hexanol compared to neat diesel fuel operation. The combustion duration is increased by 2.66˚CA for 40% 1-Hexanol at 60% load compared to neat diesel fuel. However, an improvement in net heat release rate is noted which is 13.95% higher at 60% load for 40% 1-Hexanol, this increment is due to prolonged ignition delay. With the use of 1-Hexanol in the engine, there is a drastic reduction in nitrogen oxide emission is observed, this is the greatest impact of 1-Hexanol. However, a slight increment in the hydrocarbon and carbon monoxide emission is also noted due to poor fuel properties like lower cetane number, higher viscosity and higher latent heat of evaporation of 1-Hexanol. Compared to all other blends in the test 10% 1-Hexanol shows comparable results with pure diesel fuel, which is only 2.37% lower in brake thermal efficiency, 3.6% higher in brake specific fuel consumption, 17.55% lower in nitrogen oxide emission, 18.18% higher in hydrocarbon and 33.33% higher in carbon monoxide emission is noted. The exhaust gas recirculation helps in reducing the NOₓ emission, 40% 1-Hexanol is less sensitive to exhaust gas recirculation. Up to 40% of 1-Hexanol can be used in the CI engine without any modification. It is concluded that 1-Hexanol is a sustainable renewable biofuel due to the reason that even though the use of 1-Hexanol lowers the performance which helps in reducing the NOₓ emission greatly; the performance can be improved by modifying the engine parameters.