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Engine Speed Effect on Auto-Ignition Temperature and Low Temperature Reactions in HCCI Combustion for Primary Reference Fuels
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 13, 2014 by SAE International in United States
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Homogeneous charge compression ignition (HCCI) is a promising concept that can be used to reduce NOx and soot emissions in combustion engines, keeping efficiency as high as for diesel engines. To be able to accurately control the combustion behavior, more information is needed about the auto-ignition of fuels. Many fuels, especially those containing n-paraffins, exhibit pre-reactions before the main heat release event, originating from reactions that are terminated when the temperature in the cylinder reaches a certain temperature level. These pre-reactions are called low temperature heat release (LTHR), and are known to be affected by engine speed. This paper goes through engine speed effects on auto-ignition temperatures and LTHR for primary reference fuels. Earlier studies show effects on both quantity and timing of the low temperature heat release when engine speed is varied. In this study, these effects are further explored by looking at the auto-ignition temperatures and the pressure and temperature evolution in the cylinder.
Four primary reference fuels (PRF, blends of n-heptane and iso-octane) were used, from PRF70 to PRF100. All fuels were tested in a CFR engine with variable compression ratio, running in HCCI operation. Engine speed was varied from 600 to 1200 rpm. An equivalence ratio of 0.33 was used, and a constant combustion phasing of 3 degrees after TDC was maintained by changing the compression ratio for each operating point. Different pressure and temperature evolutions were achieved by varying the inlet air temperature in three steps from 50°C to 150 °C.
At higher engine speeds the LTHR decreased or disappeared. Auto-ignition temperature increased at higher engine speeds due to the shorter residence time in the LTHR temperature zone. The temperature range where LTHR was detected was shifted to higher temperatures with increased engine speed.
CitationTruedsson, I., Cannella, W., Johansson, B., and Tuner, M., "Engine Speed Effect on Auto-Ignition Temperature and Low Temperature Reactions in HCCI Combustion for Primary Reference Fuels," SAE Technical Paper 2014-01-2666, 2014, https://doi.org/10.4271/2014-01-2666.
- Sjöberg , M. and Dec , J. EGR and Intake Boost for Managing HCCI Low-Temperature Heat Release over Wide Ranges of Engine Speed SAE Technical Paper 2007-01-0051 2007 10.4271/2007-01-0051
- Aroonsrisopon , T. , Foster , D. , Morikawa , T. , and Iida , M. Comparison of HCCI Operating Ranges for Combinations of Intake Temperature, Engine Speed and Fuel Composition SAE Technical Paper 2002-01-1924 2002 10.4271/2002-01-1924
- Hosseini , V. , Neill , W. , and Chippior , W. Influence of Engine Speed on HCCI Combustion Characteristics using Dual-Stage Autoignition Fuels SAE Technical Paper 2009-01-1107 2009 10.4271/2009-01-1107
- Heywood , J. B. 1988 Internal Combustion Engine Fundamentals McGraw-Hill New York
- Truedsson , I. , Tuner , M. , Johansson , B. , and Cannella , W. Pressure Sensitivity of HCCI Auto-Ignition Temperature for Primary Reference Fuels SAE Int. J. Engines 5 3 1089 1108 2012 10.4271/2012-01-1128
- Truedsson , I. , Tuner , M. , Johansson , B. , and Cannella , W. Pressure Sensitivity of HCCI Auto-Ignition Temperature for Gasoline Surrogate Fuels SAE Technical Paper 2013-01-1669 2013 10.4271/2013-01-1669
- Truedsson , I. , Johansson , B. , Tuner , M. , Cannella , W. Pressure Sensitivity of HCCI Auto-ignition Temperature for Oxygenated Reference Fuels J. Eng. Gas Turbines Power 135 7 2012 10.1115/1.4023614
- Leppard , W. The Chemical Origin of Fuel Octane Sensitivity SAE Technical Paper 902137 1990 10.4271/902137
- Chen , J.S. , Litzinger , T.A. , Curran , H.J. The Lean Oxidation of Iso-Octane in the Intermediate Temperature Regime at Elevated Pressures Combustion Science and Technology 156 1 49 79 2000 10.1080/00102200008947296
- Hwang , W. , Dec , J. , Sjöberg , M. Spectroscopic and chemical-kinetic analysis of the phases of HCCI autoignition and combustion for single- and two-stage ignition fuels Combustion and Flame 154 2008 387 409 10.1016/j.combustflame.2008.03.019
- Zheng , J. , Yang , W. , Miller , D. , and Cernansky , N. Prediction of Pre-ignition Reactivity and Ignition Delay for HCCI Using a Reduced Chemical Kinetic Model SAE Technical Paper 2001-01-1025 2001 10.4271/2001-01-1025
- Mehl , M. , Pitz , W. , Sarathy , M. , Yang , Y. et al. Detailed Kinetic Modeling of Conventional Gasoline at Highly Boosted Conditions and the Associated Intermediate Temperature Heat Release SAE Technical Paper 2012-01-1109 2012 10.4271/2012-01-1109
- Vuilleumier , D. , Kozarac , D. , Mehl , M. , Saxena , S. , Pitz , W.J. , Dibble , R.W. , Chen , J. , Sarathy , M. Intermediate temperature heat release in an HCCI engine fueled by ethanol/n-heptane mixtures: An experimental and modeling study Combustion and Flame 10.1016/j.combustflame.2013.10.008