Impact of Low Reactivity Fuel Type and Energy Substitution on Dual Fuel Combustion at Different Injection Timings

Dual fuel combustion leverages a high-reactivity (HRF) to ignite premixed low reactivity (LRF)–air mixture achieve high efficiencies and engine-out emissions. The difference in the relative amounts of these fuels in-cylinder stratification profoundly impacts dual combustion. effect increasing LRF energy substitution on at various fixed HRF (diesel) quantities was experimentally studied for two different LRFs (natural gas propane) heavy-duty single cylinder engine constant intake pressure 1.5 bar injection 500 bar. Further, this three start (SOI) timings 310 CAD (50° BTDC), 330 (30° 350 (10° BTDC). For SOI, resulted higher loads, peak pressures, apparent heat release rates (AHRR). onset temperature (LTHR) advanced as LR flowrate increased given pilot quantity diesel–NG but remained diesel–propane SOIs due impact propane which LTHR occurs. indicated conversion efficiency (IFCE) ranged from 35% 4 IMEPg 47% 9 with NG 3 51% 8 LRF. HC CO emissions decreased an substitution. However, accompanied by significantly oxides nitrogen (NOx) both LRFs. consistently led second stage AHRR, whereas first AHRR relatively unchanged This IFCE all increased. studied, were substantially lower stability improved (and consequently, load) To best authors’ knowledge, present work is unique that it involves systematic experimental study over range SOIs, providing comparative results (NG same platform.