COMPUTATIONAL STUDY OF REACTIVITY CONTROLLED COMPRESSION IGNITION (RCCI) COMBUSTION IN A HEAVY-DUTY DIESEL ENGINE USING NATURAL GAS

摘要

Varying quantity of diesel fuel in pilot vs main controls reactivity mixture and can influence combustion phasing and rate of pressure rise. 17.5% NOx reduction with 78% soot reduction at Full Power (1800rpm) using AFR 19.8 and EGR 36.5%. Mfuel tot 267mg. 20% diesel double injection strategy with a SOIp at -55degATDC and a SOlm at 6.3degATDC achieved 164g/kWhr. 24% improvement over baseline. Pmax and RoPR increased over baseline diesel case although acceptable. Soot reduction from the RCCI case was result of fewer fuel rich regions at high temperatures (due to premixing), as well as a fundamental difference in the fuel type (NG versus diesel). Therefore, RCCI using NG and diesel mixtures could be viable path to full power, provided combustion stability isn't compromised.