An Experimental and Modeling Study of HCCI Combustion Using n-Heptane

Homogeneous charge compression ignition (HCCI) is an advanced low-temperature combustion technology being considered for internal combustion engines due to its potential for high fuel conversion efficiency and extremely low emissions of particulate matter and oxides of nitrogen (NOx). In its simplest form, HCCI combustion involves the auto-ignition of a homogeneous mixture of fuel, air, and diluents at low to moderate temperatures and high pressure. Previous research has indicated that fuel chemistry has a strong impact on HCCI combustion. This paper reports the preliminary results of an experimental and modeling study of HCCI combustion using n-heptane, a volatile hydrocarbon with well known fuel chemistry. A Co-operative Fuel Research (CFR) engine was modified by the addition of a port fuel injection system to produce a homogeneous fuel-air mixture in the intake manifold, which contributed to a stable and repeatable HCCI combustion process. Detailed experiments were performed to explore the effects of critical engine parameters such as intake temperature, compression ratio, air/fuel ratio, engine speed, turbocharging, and intake mixture throttling on HCCI combustion. The influence of these parameters on the phasing of the low-temperature reaction, main combustion stage, and negative temperature coefficient delay period are presented and discussed. A single-zone numerical simulation with detailed fuel chemistry was developed and validated. The simulations show good agreement with the experimental data and capture important combustion phase trends as engine parameters are varied.

[1]  D. Foster,et al.  Compression-Ignited Homogeneous Charge Combustion , 1983 .

[2]  G. A. Lavoie,et al.  Modeling of HCCI Combustion and Emissions Using Detailed Chemistry , 2001 .

[3]  Hua Zhao,et al.  Effect of Injection Timing on Mixture and CAI Combustion in a GDI Engine with an Air-Assisted Injector , 2006 .

[4]  John M. Simmie,et al.  Detailed Chemical Kinetic Modeling of Surrogate Fuels for Gasoline and Application to an HCCI Engine , 2005 .

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

[6]  M. David Checkel,et al.  Novel Method of Setting Initial Conditions for Multi-Zone HCCI Combustion Modeling , 2007 .

[7]  Nebojsa Milovanovic,et al.  A Review of Experimental and Simulation Studies on Controlled Auto-Ignition Combustion , 2001 .

[8]  Bengt Johansson,et al.  Demonstrating the Multi Fuel Capability of a Homogeneous Charge Compression Ignition Engine with Variable Compression Ratio , 1999 .

[9]  John E. Dec,et al.  An Investigation of the Relationship Between Measured Intake Temperature, BDC Temperature, and Combustion Phasing for Premixed and DI HCCI Engines , 2004 .

[10]  M. D. Checkel,et al.  Investigating the Effects of Reformed Fuel Blending in a Methane- or n-Heptane-HCCI Engine Using a Multi-Zone Model , 2007 .

[11]  Fuquan Zhao,et al.  Homogeneous charge compression ignition (HCCI) engines : key research and development issues , 2003 .

[12]  William H. Green,et al.  PREDICTION OF PERFORMANCE MAPS FOR HOMOGENEOUS-CHARGE COMPRESSION-IGNITION ENGINES , 2004 .

[13]  W. Stuart Neill,et al.  An Experimental Investigation on the Emission Characteristics of HCCI Engine Operation Using N-Heptane , 2007 .

[14]  A. Megaritis,et al.  Experimental Investigation into HCCI Combustion Using Gasoline and Diesel Blended Fuels , 2005 .

[15]  J. Dec,et al.  The Potential of HCCI Combustion for High Efficiency and Low Emissions , 2002 .

[16]  T. W. Ryan,et al.  HCCI Fuels Evaluations-Gasoline Boiling Range Fuels , 2005 .

[17]  C. Westbrook,et al.  A Comprehensive Modeling Study of n-Heptane Oxidation , 1998 .

[18]  G. Woschni.  A Universally Applicable Equation for the Instantaneous Heat Transfer Coefficient in the Internal Combustion Engine , 1967 .

[19]  John B. Heywood,et al.  Internal combustion engine fundamentals , 1988 .

[20]  Jialin Yang,et al.  Development of a Gasoline Engine System Using HCCI Technology - The Concept and the Test Results , 2002 .

[21]  Yukiyasu Tanaka,et al.  A Study on Gasoline Engine Combustion by Observation of Intermediate Reactive Products during Combustion , 1979 .

[22]  H. Ciezki,et al.  Shock-tube investigation of self-ignition of n-heptane - Air mixtures under engine relevant conditions , 1993 .

[23]  M. David Checkel,et al.  A Stand-Alone Multi-Zone Model for Combustion in HCCI Engines , 2005 .

[24]  Zoran Filipi,et al.  New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux , 2004 .

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

[26]  Hua Zhao,et al.  Effects of Air/Fuel Ratios and EGR Rates on HCCI Combustion of n-heptane, a Diesel Type Fuel , 2003 .

[27]  S. H. Jo,et al.  Active Thermo-Atmosphere Combustion (ATAC) - A New Combustion Process for Internal Combustion Engines , 1979 .

[28]  Steve Richardson,et al.  Modelling of HCCI Engines: Comparison of Single-zone, Multi-zone and Test Data , 2005 .