Experimental investigation of iso-butanol/diesel reactivity controlled compression ignition combustion in a non-road diesel engine

As non-road engine emission control programs are developed largely in number of countries around the world, adopting a high efficiency and low emission combustion techniques has become essential. Flexible fuel operation using in-cylinder blending technique is a primary option for using higher octane fuel in a non-road diesel engine to mitigate emissions and fossil fuel dependency. In the present study, iso-butanol/diesel dual fuel reactivity controlled compression ignition concept is preferred considering the benefits of iso-butanol over other alcohol fuels and better combustion control over other low temperature combustion concepts. An experimental investigation is performed on a suitably modified single cylinder non-road diesel engine for the entire load range (0-100% engine full load) focusing on the effect of operating parameters (iso-butanol mass fraction, diesel injection timing, diesel injection pressure, diesel mass in split injection, and intake air temperature) on the dual fuel combustion, performance and emission characteristics. The reactivity controlled compression ignition combustion is analyzed at each load condition and the best operating points are selected based on brake thermal efficiency and emissions. The results indicated that increase in iso-butanol mass fraction with advanced start of injection of direct injected diesel fuel showed a 99% reduction in oxides of nitrogen and a 91% reduction in smoke emissions with 4.5% increase in brake thermal efficiency. Further the drawback in dual fuel combustion, hydrocarbon emission is reduced by 65% with an increase of intake air temperature from 303 K to 338 K. Also, both hydrocarbon and carbon monoxide emissions are reduced with increase in diesel injection pressure and mass of diesel fuel injected in first injection due to the enhanced mixture formation.