Effects of MBT spark timing on performance emission and combustion characteristics of S.I engine using hydrogen-CNG blends

This paper shows the effects of 0%, 5%, 10% and 15% blends of hydrogen by energy with Compressed Natural Gas (CNG) on multi-cylinder bi-fuel spark ignition engine using sequential port fuel injection system. At WOT (Wide Open Throttle) position MBT (Maximum Brake Torque) spark timing shown improvement in performance parameters with reduction in NOx emission. MBT spark timing increased with increase in speed and decreased with increase in hydrogen addition for all fuel blends. Hydrocarbon (HC) and carbon monoxide (CO) emissions rose up with decrease in equivalence ratio and reduced with increase in HCNG blends. Hydrogen addition had shown rise in peak pressure, increase in heat release rate and decrease in combustion duration. The optimum MBT spark timing observed for 5% hydrogen blend at 2500 rpm is 25 degrees CABTDC for compromise with oxides of nitrogen (NOx) and performance output. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.