TY - JOUR
T1 - Autoignition quality of gasoline fuels in partially premixed combustion in diesel engines
AU - Kalghatgi, G. T.
AU - Hildingsson, L.
AU - Harrison, A. J.
AU - Johansson, B.
N1 - Funding Information:
Huw Jones and Bob Head at the Shell Technology Centre Thornton (STCT) made the engine experiments possible. The collaboration with Lund University , particularly Leif Hildingsson’s stay at STCT, was made possible by the EU contract, MTKI-CT-2006-042242 Marie Curie Engine Efficiency, under the Marie Curie Programme.
PY - 2011
Y1 - 2011
N2 - A single-cylinder diesel engine has been run on gasolines of different octane numbers and on model fuels, mixtures of iso-octane, n-heptane and toluene, at different operating conditions. The autoignition quality of the fuel is best described by an Octane Index, OI = (1 - K) · RON + K · MON for fuels in the gasoline autoignition range where RON and MON are, respectively, the Research and Motor Octane numbers and K is an empirical constant which is measured to be negative. Hence for a given RON, a non-paraffinic fuel, of lower MON, will have higher OI and more resistance to autoignition. For a given operating condition, ignition delay increases non-linearly with OI and changes little over the autoignition range of practical diesel fuels. Heat release following the autoignition is influenced by the stratification which will increase as the time between the end of injection and start of combustion decreases and combustion phasing parameters such as Combustion Delay, the difference between the 50% burn time and the start of injection, become less correlated with fuel autoignition quality. Higher ignition delays facilitate premixed combustion in the diesel engine. If two fuels have similar combustion phasing at the same injection timing, their emissions performance is also similar. Hence a good surrogate for gasoline in partially premixed compression ignition engines is a mixture of toluene, iso-octane and n-heptane with the same RON and MON.
AB - A single-cylinder diesel engine has been run on gasolines of different octane numbers and on model fuels, mixtures of iso-octane, n-heptane and toluene, at different operating conditions. The autoignition quality of the fuel is best described by an Octane Index, OI = (1 - K) · RON + K · MON for fuels in the gasoline autoignition range where RON and MON are, respectively, the Research and Motor Octane numbers and K is an empirical constant which is measured to be negative. Hence for a given RON, a non-paraffinic fuel, of lower MON, will have higher OI and more resistance to autoignition. For a given operating condition, ignition delay increases non-linearly with OI and changes little over the autoignition range of practical diesel fuels. Heat release following the autoignition is influenced by the stratification which will increase as the time between the end of injection and start of combustion decreases and combustion phasing parameters such as Combustion Delay, the difference between the 50% burn time and the start of injection, become less correlated with fuel autoignition quality. Higher ignition delays facilitate premixed combustion in the diesel engine. If two fuels have similar combustion phasing at the same injection timing, their emissions performance is also similar. Hence a good surrogate for gasoline in partially premixed compression ignition engines is a mixture of toluene, iso-octane and n-heptane with the same RON and MON.
KW - Autoignition
KW - CI engines
KW - Gasoline
KW - Octane Index
KW - Reference fuel
UR - http://www.scopus.com/inward/record.url?scp=79251615423&partnerID=8YFLogxK
U2 - 10.1016/j.proci.2010.07.007
DO - 10.1016/j.proci.2010.07.007
M3 - Article
AN - SCOPUS:79251615423
SN - 1540-7489
VL - 33
SP - 3015
EP - 3021
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
IS - 2
ER -