Investigations on the combustion duration and ignition delay period of a dual fuel diesel engine with hydrogen and producer gas as secondary fuels

This paper presents an experimental investigation on the combustion duration and ignition delay of a dual fuel diesel engine using hydrogen, producer gas and mixture of producer gas and hydrogen in different proportion as a secondary fuel with diesel as pilot fuel at wide range of load conditions. Experiments were conducted on a 4 cylinder turbocharged and intercooled 62.5 kW gen-set diesel engine at constant speed of 1500 rpm. It was found that, at lower load condition when only hydrogen is used as 30% secondary fuel, the combustion duration is increased by 2.5°CA and ignition delay by 2°CA. Moreover, at 80% load condition and for 50% of hydrogen substitution maximum reduction in combustion duration is 5°CA whereas, ignition delay decreases. The maximum increment in combustion duration at 80% load condition for 50% of producer gas substitution is 9°CA while for ignition delay it is 6°CA. In mixed fuel mode (PG + H2) (Case IV), the combustion duration and ignition delay are lesser than when producer gas alone (Case III) is used as fuel. Further, mixture combination of PG:H2 = (60:40)% is found to be the most suited one at which the combustion duration and ignition delay are in good comparison to that of pure diesel operation. Additionally, it is observed that the ignition delay of dual fuel engine depends not only on the type of gaseous fuels and their concentrations but also on charge temperature, pressure and oxygen concentration.