TY - JOUR
T1 - Optical diagnostics on the effects of fuel properties and coolant temperatures on combustion characteristic and flame development progress from HCCI to CDC via PPC
AU - Cui, Yanqing
AU - Liu, Haifeng
AU - Geng, Chao
AU - Tang, Qinglong
AU - Feng, Lei
AU - Wang, Yu
AU - Yi, Wentao
AU - Zheng, Zunqing
AU - Yao, Mingfa
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to acknowledge the financial support to the research provided by the National Natural Science Foundation of China through the Project of 91941102 and 51922076. The authors would also like to thank Dr Raza Mohsin from Shanghai Jiao Tong University for his great help in the revision process.
PY - 2020/2/26
Y1 - 2020/2/26
N2 - The effects of fuel properties and coolant temperatures on combustion characteristic and flame development progress were investigated in an optical engine. The combustion mode was transited from homogeneous charge compression ignition (HCCI) to conventional diesel combustion (CDC) via partially premixed combustion (PPC) by changing the start of injection (SOI) timings from early to late injections. The main fuel properties were separated by using diesel, n-heptane, iso-octane, n-butanol and their mixtures. Diagnostics included conventional in-cylinder pressure and heat-release analysis, high-speed imaging and the spatially integrated flame luminosity intensity. The results show that the variation of combustion phasing (CA50) is more sensitive to the variation of fuel properties of cetane number, latent heat and atomic oxygen at all tested combustion modes. However, fuel physical properties such as dilution, viscosity and volatility only have significant effects at HCCI, while minor effects at PPC and CDC. Fuel properties have minor effects on flame development progress, but significant effects on maximum value of natural flame luminosity intensity. At SOI-15, the main factor to reduce the maximum value of natural flame luminosity intensity is the dilution, viscosity and volatility (40%) followed by the latent heat and the atomic oxygen (18.5%) and cetane number (1.6%). At SOI-5, the main factor is the cetane number (44.1%) followed by the latent heat and the atomic oxygen (36.2%) and dilution, viscosity and volatility (2.4%). Coolant temperature significantly influences combustion phasing and peak in-cylinder pressure and heat release rate at early injection timings, but these effects weaken at late injection timings.
AB - The effects of fuel properties and coolant temperatures on combustion characteristic and flame development progress were investigated in an optical engine. The combustion mode was transited from homogeneous charge compression ignition (HCCI) to conventional diesel combustion (CDC) via partially premixed combustion (PPC) by changing the start of injection (SOI) timings from early to late injections. The main fuel properties were separated by using diesel, n-heptane, iso-octane, n-butanol and their mixtures. Diagnostics included conventional in-cylinder pressure and heat-release analysis, high-speed imaging and the spatially integrated flame luminosity intensity. The results show that the variation of combustion phasing (CA50) is more sensitive to the variation of fuel properties of cetane number, latent heat and atomic oxygen at all tested combustion modes. However, fuel physical properties such as dilution, viscosity and volatility only have significant effects at HCCI, while minor effects at PPC and CDC. Fuel properties have minor effects on flame development progress, but significant effects on maximum value of natural flame luminosity intensity. At SOI-15, the main factor to reduce the maximum value of natural flame luminosity intensity is the dilution, viscosity and volatility (40%) followed by the latent heat and the atomic oxygen (18.5%) and cetane number (1.6%). At SOI-5, the main factor is the cetane number (44.1%) followed by the latent heat and the atomic oxygen (36.2%) and dilution, viscosity and volatility (2.4%). Coolant temperature significantly influences combustion phasing and peak in-cylinder pressure and heat release rate at early injection timings, but these effects weaken at late injection timings.
UR - http://hdl.handle.net/10754/661944
UR - https://linkinghub.elsevier.com/retrieve/pii/S0016236120304361
UR - http://www.scopus.com/inward/record.url?scp=85079852464&partnerID=8YFLogxK
U2 - 10.1016/j.fuel.2020.117441
DO - 10.1016/j.fuel.2020.117441
M3 - Article
SN - 0016-2361
VL - 269
SP - 117441
JO - Fuel
JF - Fuel
ER -