Effect of hydrogen enrichment on the performance emissions and combustion parameters of a complete biofueled diesel engine

Abstract

Emission from engine exhaust is series problem for environment point of view. For that search for alternative fuel is encouraged. The main problems with the use of neat vegetable oils in diesel engines are higher smoke levels and lower thermal efficiency as compared to diesel. The problem can be tackled by inducting a gaseous fuel in the intake manifold along with air. In this investigation, hydrogen is used as the inducted fuel. It is expected that, the problems associated with vegetable oil fueled engine like smoke and hydrocarbon emissions can be brought down by supplying hydrogen in small quantities along with air. Experiments were conducted to evaluate the performance emission and combustion parameters in a compression ignition engine primarily fuelled with an emulsion of bio-oil produced from pyrolysis of biomass source and methyl ester of karanja with different quantities of hydrogen being inducted. The brake thermal efficiency was 28.64% and 32.02% with diesel and WPO-MEK oil without hydrogen operation respectively at full load. MEK oil has less viscosity and better volatility compared to diesel which causes better injection, mixing and evaporation characteristics results in a increasing in brake thermal efficiency. The brake thermal efficiency was 36.57%, 38.5% with 2lpm and 4lpm hydrogen enrichment at full load. The high flame velocity of hydrogen contributed to better mixing of methyl ester oil with air which leads to improvements in thermal efficiency. The maximum thermal efficiency was recorded with 4lpm hydrogen enrichment. However, the dual fuel operation reduces the HC and CO emissions considerably. Since hydrogen has no carbon, burning of hydrogen different flow rates along with wpo10 is reduced HC and CO emissions compared to wpo10 without hydrogen.