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Analysis of Cyclic Variation and the Effect of Fuel Stratification on Combustion Stabilityin a Port Fuel Injection (PFI) CAI Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 20, 2009 by SAE International in United States
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CAI engine is well known to be advantageous over conventional SI engines because it facilitates higher engine efficiency and lower emission (NOx and smoke). However, its limited operation range, large cyclic variation, and difficulty in heat release control are still unresolved obstacles. Previous studies showed that a high load range of the CAI engine is limited mainly by the combustion noise caused by a stiff pressure rise (knock), and that a low load range is also limited by the combustion instability caused by the high dilution of residual gas.
In this study, the characteristics of each cycle were analyzed to find the cause of the cycle variation at the high load limit of CAI operation. Moreover, to improve combustion stability, we tested the in-cylinder fuel stratification by applying nonsymmetrical fuel injection to the intake port. Experiments were performed on a PFI single cylinder research engine equipped with dual CVVT and low lift (2 mm) cam shaft with NVO strategy. The in-house RGF prediction model was used to predict the cycle by cycle differences of in-cylinder trapped mass, RGF and bulk temperature.
The result of cyclic analysis shows that cyclic variation is caused by the cycle transition between normal combustion and knock when the in-cylinder charge condition changed. Non-uniformity of in-cylinder fuel concentration reduces the frequency at which the knock occurred by about 20 %. Due to this reduction of the number of knock cycle, NIMEP is increased about 5 %, COVIMEP improved about 1 %, Rmax, which represents the combustion noise, reduced about 20 % and NOx reduced about 15 %.
CitationChoi, S., Lim, J., Ki, M., Min, K. et al., "Analysis of Cyclic Variation and the Effect of Fuel Stratification on Combustion Stabilityin a Port Fuel Injection (PFI) CAI Engine," SAE Technical Paper 2009-01-0670, 2009, https://doi.org/10.4271/2009-01-0670.
Homogeneous Charge Compression Ignition Engines, 2009
Number: SP-2242; Published: 2009-04-20
Number: SP-2242; Published: 2009-04-20
- Koopmans L. Ogink R. Denbratt I. “Direct Gasoline Injection in the Negative Valve Overlap of Homogeneous Charged Compression Ignition Engines” SAE 2003-01-1854 JSAE 20030195 2003
- Zhao H. et al. “Understanding the Effect of Recycled Burnt Gases on the Controlled Auto Ignition (CAI) Combustion in Four-Stroke Gasoline Engines” SAE 2001-01-3607 2001
- Stanglmaier R.H. Robets C.E. “Homogeneous Charged Compression Ignition (HCCI): Benefits, Compromise and Future Applications” SAE 1999-01-3682 1999
- Eng J. A. “Characterization of Pressure Waves in HCCI Combustion” SAE 2002-01-2859 2002
- Wolters P. Salber W. Geiger J. Duesmann M. “Controlled Auto Ignition Combustion Process with an Electromechanical Valve Train” SAE 2003-01-0032 2003
- Sjöberg Magnus Dec John E. Babajimopoulos Aristotelis Assanis Dennis “Comparing Enhanced Natural Thermal Stratification Against Retarded Combustion Phasing for Smoothing of HCCO Heat-Release Rates” SAE 2004-01-2994 2004
- Sjöberg Magnus Dec John E. “Effects of Engine Speed, Fueling Rate and Combustion Phasing on the Thermal Stratification Required to Limit HCCI Knocking Intensity” SAE 2005-01-2125 2005
- Cairns Alasdair Blaxill Hugh “Lean Boost and External Exhaust Gas Recirculation for High Load Controlled Auto-Ignition” SAE 2005-01-3744 2005
- Cairns Alasdair Blaxill Hugh “The Effect of Combined Internal and External Exhaust Gas Recirculation on Gasoline Controlled Auto-Ignition” SAE 2005-01-0133 2005
- Thirouard B. Cherel j. Knop V. “Investigation of Mixture Quality Effect on CAI Combustion” SAE 2005-01-0141 2005
- Mori S. Lang O. Pischinger S. et al. “Type Analysis of EGR-Strategies for Controlled Auto Ignition (CAI) by Using Numerical Simulations and Optical Measurements” SAE 2006-01-0630 2006
- Knop Vincent Thirouard Benoist Chérel Jérome “Influence of the Local Mixture Characteristics on the Combustion Process in a CAI ™ Engine” SAE 2008-01-1671 2008
- Dec John E. Sjöberg Magnus “A Parametric Study of HCCI Combustion - the Sources of Emissions at Low Loads and the Effects of GDI Fuel Injection” SAE 2003-01-0752 2003
- Urushihara Tomonori Hiraya Koji Kakuhou Akihiko Itoh Teruyuki “Expansion of HCCI Operating Region by the Combination of Direct Fuel Injection, Negative Valve Overlap and Internal Fuel Reformation” SAE 2003-01-0749 2003
- Choi Seungmok Ki Minyoung Min Kyoundoug et al. “An On-Line Model for Predicting Residual Gas Fraction by Measuring Intake/Exhaust and Cylinder Pressure in CAI Engine” SAE 2008-01-0540 2008
- Benson Rowland S. Clarendon Press Oxford “The Thermodynamics and Gas Dynamics of Internal-Combustion Engines” 1982