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Study on the Pre-Chamber Fueling Ratio Effect on the Main Chamber Combustion Using Simultaneous PLIF and OH* Chemiluminescence Imaging
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
Pre-chamber combustion (PCC) promotes the combustion of a lean fuel-air mixture by improving its ignitability, which aids in reduced emissions and increased efficiency. Typically the geometry of the pre-chamber (PC) and the fuel concentration affect its performances. To understand the dynamics of the PCC in practical engine conditions, the present study focuses on (i) relating the events in the main chamber (MC) with the measured pressure traces and, (ii) the effect of fuel concentration on the MC combustion characteristics, using laser diagnostics. We performed simultaneous acetone planar laser-induced fluorescence (PLIF) from the side and OH* imaging from the bottom in a heavy-duty optical engine for two PC fueling ratios (PCFR). PCFR is the ratio of PC fuel to the total fuel, which in this study is considered to be 7% and 13%. The “negative” regions of the PLIF fields are used to visualize the PC jets and the main chamber combustion. The absence of acetone seeding in the PC, and its consumption during the MC combustion contribute to the loss of PLIF signal (negative regions). The instantaneous PLIF/OH* fields show the appearance of the PC jets near PC pressure maxima. The PC jet interacting with the piston is accompanied by an increase in OH* intensity and area. Increasing the PCFR results in a lag of ~ 0.6° crank angle in the PC and MC pressure traces and the pressure difference between PC and MC (ΔpPC-MC). This leads to a phase lag in the PC flame jet penetration distance, which in turn results in a delayed increase in the total OH* intensity for the higher PCFR case. For similar ΔpPC-MC, we observed wider OH* regions with increased PCFR. This highlights the radical concentration effect on the MC combustion apart from the fluid mechanical effects due to ΔpPC-MC.
- Ramgopal Sampath - King Abdullah University of Science & Technology
- Qinglong Tang - King Abdullah University of Science & Technology
- Manuel Echeverri Marquez - King Abdullah University of Science & Technology
- Priybrat Sharma - King Abdullah University of Science & Technology
- Ponnya Hlaing - King Abdullah University of Science & Technology
- Moez Ben Houidi - King Abdullah University of Science & Technology
- Emre Cenker - Saudi Aramco
- Junseok Chang - Saudi Aramco
- Bengt Johansson - King Abdullah University of Science & Technology
- Gaetano Magnotti - King Abdullah University of Science & Technology