On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

Abstract A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of injection timings.

[1]  R. Reitz,et al.  MODELING SPRAY ATOMIZATION WITH THE KELVIN-HELMHOLTZ/RAYLEIGH-TAYLOR HYBRID MODEL , 1999 .

[2]  Junepyo Cha,et al.  High Pressure and Split Injection Strategies for Fuel Efficiency and Emissions in DI Diesel Engine , 2015 .

[3]  S. M. Sarathy,et al.  A methodology to relate octane numbers of binary and ternary n-heptane, iso-octane and toluene mixtures with simulated ignition delay times , 2015 .

[4]  Hongming Xu,et al.  Performance of straight-run naphtha single- and two-stage combustion modes from low to high load , 2013 .

[5]  William L. Roberts,et al.  Surrogate fuel formulation for light naphtha combustion in advanced combustion engines , 2015 .

[6]  John E. Dec,et al.  Advanced compression-ignition engines—understanding the in-cylinder processes , 2009 .

[7]  Ming Jia,et al.  Development of a New Skeletal Chemical Kinetic Model of Toluene Reference Fuel with Application to Gasoline Surrogate Fuels for Computational Fluid Dynamics Engine Simulation , 2013 .

[8]  J. Zádor,et al.  Kinetics of elementary reactions in low-temperature autoignition chemistry , 2011 .

[9]  William L. Roberts,et al.  Primary Reference Fuels (PRFs) as Surrogates for Low Sensitivity Gasoline Fuels , 2016 .

[10]  Rolf D. Reitz,et al.  Surrogate Model Development for Fuels for Advanced Combustion Engines , 2011 .

[11]  John E. Dec,et al.  Smoothing HCCI Heat-Release Rates Using Partial Fuel Stratification with Two-Stage Ignition Fuels , 2006 .

[12]  Timothy J. Callahan,et al.  HCCI in a Variable Compression Ratio Engine-Effects of Engine Variables , 2004 .

[13]  Yoann Viollet,et al.  Fuel Economy Potential of Partially Premixed Compression Ignition (PPCI) Combustion with Naphtha Fuel , 2013 .

[14]  P. J. O'rourke,et al.  Statistical properties and numerical implementation of a model for droplet dispersion in a turbulent gas , 1989 .

[15]  M. Musculus,et al.  Conceptual models for partially premixed low-temperature diesel combustion , 2013 .

[16]  Gautam Kalghatgi,et al.  Fuel/Engine Interactions , 2013 .

[17]  Caroline L. Genzale,et al.  Comparison of Diesel Spray Combustion in Different High-Temperature, High-Pressure Facilities , 2010 .

[18]  Bengt Johansson,et al.  Fuel Octane Effects in the Partially Premixed Combustion Regime in Compression Ignition Engines , 2009 .

[19]  Bengt Johansson,et al.  Surrogate fuels for premixed combustion in compression ignition engines , 2011 .

[20]  Terukazu Nishimura,et al.  Dual Mode Combustion Concept With Premixed Diesel Combustion by Direct Injection Near Top Dead Center , 2003 .

[21]  Bengt Johansson,et al.  Gasoline partially premixed combustion, the future of internal combustion engines? , 2011 .

[22]  Gautam Kalghatgi,et al.  The outlook for fuels for internal combustion engines , 2014 .

[23]  Jihad Badra,et al.  Ignition delay measurements of light naphtha: A fully blended low octane fuel , 2017 .

[24]  Derek Bradley,et al.  Engine autoignition: The relationship between octane numbers and autoignition delay times , 2006 .

[25]  Stephen Ciatti,et al.  Computational Fluid Dynamics Simulation of Gasoline Compression Ignition , 2015 .

[26]  Bengt Johansson,et al.  HCCI Combustion Phasing in a Multi Cylinder Engine Using Variable Compression Ratio , 2002 .

[27]  John E. Dec,et al.  Tailoring HCCI heat-release rates with partial fuel stratification: Comparison of two-stage and single-stage-ignition fuels , 2011 .

[28]  C. Lee,et al.  An Efficient and Unified Combustion Model for CFD of SI and CI Engine Operation , 2017 .

[29]  Bengt Johansson,et al.  Operating range in a Multi Cylinder HCCI engine using Variable Compression Ratio , 2003 .

[30]  T. Bruno,et al.  Application of the Advanced Distillation Curve Method to Fuels for Advanced Combustion Engine Gasolines , 2015 .

[31]  C. Westbrook,et al.  Kinetic modeling of gasoline surrogate components and mixtures under engine conditions , 2011 .

[32]  John E. Dec,et al.  Isolating the Effects of Fuel Chemistry on Combustion Phasing in an HCCI Engine and the Potential of Fuel Stratification for Ignition Control , 2004 .

[33]  William Cannella,et al.  Partial Fuel Stratification to Control HCCI Heat Release Rates: Fuel Composition and Other Factors Affecting Pre-Ignition Reactions of Two-Stage Ignition Fuels , 2011 .

[34]  Samveg Saxena,et al.  Fundamental phenomena affecting low temperature combustion and HCCI engines, high load limits and strategies for extending these limits , 2013 .

[35]  Aamir Farooq,et al.  Ignition of alkane-rich FACE gasoline fuels and their surrogate mixtures , 2015 .

[36]  William L. Roberts,et al.  Compositional effects on the ignition of FACE gasolines , 2016 .

[37]  S. Subramanian,et al.  An Experimental Investigation of Low Octane Gasoline in Diesel Engines , 2010 .

[38]  S M Aceves,et al.  A fully coupled computational fluid dynamics and multi-zone model with detailed chemical kinetics for the simulation of premixed charge compression ignition engines , 2005 .

[39]  Tiziano Faravelli,et al.  Detailed Chemistry Promotes Understanding of Octane Numbers and Gasoline Sensitivity , 2006 .

[40]  Jihad Badra,et al.  A Simple Method to Predict Knock Using Toluene, N-Heptane and Iso-Octane Blends (TPRF) as Gasoline Surrogates , 2015 .

[41]  Yoann Viollet,et al.  Enabling High Efficiency Direct Injection Engine with Naphtha Fuel through Partially Premixed Charge Compression Ignition Combustion , 2012 .

[42]  A. A. Amsden,et al.  KIVA-II: A Computer Program for Chemically Reactive Flows with Sprays , 1989 .

[43]  Gautam Kalghatgi,et al.  Auto-Ignition Quality of Practical Fuels and Implications for Fuel Requirements of Future SI and HCCI Engines , 2005 .

[44]  William J. Pitz,et al.  An Approach for Formulating Surrogates for Gasoline with Application toward a Reduced Surrogate Mechanism for CFD Engine Modeling , 2011 .

[45]  Kai Morganti.  A study of the knock limits of liquefied petroleum gas (LPG) in spark-ignition engines , 2013 .

[46]  G. T. Kalghatgi,et al.  WITHDRAWN: Developments in internal combustion engines and implications for combustion science and future transport fuels , 2014 .

[47]  Zhi Wang,et al.  Load expansion of naphtha multiple premixed compression ignition (MPCI) and comparison with partially premixed compression ignition (PPCI) and conventional diesel combustion (CDC) , 2014 .