Combined effect of inlet pressure, total cycle energy, and start of injection on low load reactivity controlled compression ignition combustion and emission characteristics in a multi-cylinder heavy-duty engine fueled with gasoline/diesel

Reactivity controlled compression ignition (RCCI) is demonstrated as a controllable high efficiency and clean combustion strategy, which is confirmed to be affected by either inlet pressure (IP), total cycle energy (Etotal), or start of injection (SOI). This paper discussed their combined effect on low load RCCI combustion and emission characteristics in a multi-cylinder heavy-duty engine fueled with gasoline/diesel. Results show that low temperature heat release (LTHR) only occurs when SOI is sufficiently advanced. Combustion duration (CD) is lengthened, shortened and unchanged with SOI advance under different Etotals, while lengthened with IP increase. NOX emission first increases and then decreases with SOI advance, and declines with IP increase or Etotal decrease. Trend CO changes with SOI or IP becomes opposite at the lowest Etotal, comparing with that at relatively high Etotals. HC emission decreases with SOI advance or Etotal increase, while it is insensitive to IP. Trend number of nuclear particle (Numn) changes with IP becomes opposite at the highest Etotal, comparing with that at relatively low Etotals, while Numn decreases with SOI advance or Etotal increase. Both number of aggregated particle (Numa) and soot first decreases and then increases with SOI advance, and decreases with Etotal decrease or IP increase.