Exhaust emissions at the co-combustion of biomass-based biofuels and hydrogen in a compression ignition engine

Abstract

The manuscript presents the investigation on co-combustion of biomass based biofuels with hydrogen in compression ignition engine. Hydrogen fraction in the range from 0 to 40% by energy was examined. The main target was to determine the impact of hydrogen on the exhaust opacity and toxic emissions in the CI engine. The investigation was performed on a single cylinder compression ignition engine with common rail injection. Hydrogen was injected into the intake manifold, where homogeneous mixture with air was composed before sucked into the cylinder. Tests were performed at both fixed and optimal injection timings at partial and full engine load. Results of the experiments show that increasing amounts of hydrogen contributes the shorten ignition delay time that also affect main combustion phase. Additionally, it implicates heat release rate and decrease of CO, CO2, HC and exhaust opacity with increase of hydrogen energy fraction. The optimal hydrogen energy fraction of 13 – 17% was defined with respect to NO emissions, while the range of 20 – 25% is more favorable considering all exhaust emissions and engine performance.