Investigating the Effects of Varying the Intake Air Temperature and Pressure on the Performance and Emissions of RCCI Engines

In this paper, the effects of varying intake air temperature and pressure on RCCI engine are investigated. Combustion in an RCCI engine is controlled by varying the fuel reactivity in the combustion chamber, but it also affects some initial states and consequently performance parameters such as NOx formation and Ringing Intensity. In this paper, iso-octane as a low reactivity fuel and n-heptane as a high reactivity fuel have been used, and both speed and load have been swept to investigate the engine performance parameters. Different points in the engine performance interval from 1300rpm to 3100rpm have been considered, while varying the iso-octane to n-heptane ratio in a total fuel mass of 60mg and 100mg. The intake air temperature has been varied from -20℃ to 60℃ and its pressure from 30 to 60kPa. Lower NOx and Ringing Intensity and higher thermal efficiency are the best criteria for a good combustion in an RCCI engine. Therefore, based upon these criteria, the best conditions for a normal combustion are determined by varying the intake air temperature and pressure.