Application of electronic fuel injection lead to rate shaping of fuel at different injection pressures on
internal combustion engines. In the present study, an experimental investigation was performed to study the influence of multiple injections on a modified single cylinder air-cooled diesel engine operating in reactivity controlled compression ignition combustion mode-a clean combustion mode with higher thermal efficiency, in which extensive research is being performed now a days to meet emission norms. One of the key characteristics of this combustion mode is combustion phasing control, by varying fuel reactivity distributions prior to start of ignition that greatly influences combustion process. Diesel injection pressure and the split diesel fuel mass has a vast impact on fuel reactivity. Methanol has been injected at port (a low reactivity fuel) and diesel has been injected directly into the cylinder. The RCCI combustion strategy was realized at no load by varying high reactivity diesel injection pressure from 400 bar to 600 bar and start of injection mass variation from 40% to 80%. It was found from the investigation that increasing the injection pressure from 400 bar to 600 bar had a better effect on combustion parameters and emissions. At 60% fuel injection mass, the indicated thermal efficiency and emissions showed a better result than other combinations.
Keywords Fuel Injection timing, Injection pressure, Fuel reactivity, Compression ignition, Methanol, Low reactive fuel