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On the origin of Unburned Hydrocarbon Emissions in a Wall Guided, Low NOx Diesel Combustion System
Technical Paper
2007-01-1836
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The formation mechanisms of unburned hydrocarbons (HC) in low NOx, homogeneous type Diesel combustion have been investigated in both standard and optical access single cylinder engines operating under low load (2 and 4 bar IMEP) conditions. In the standard (i.e. non-optical) engine, parameters such as injection timing, intake temperature and global equivalence ratio were varied in order to analyse the role of bulk quenching on HC emissions formation. Laser-induced fluorescence (LIF) imaging of in-cylinder unburned HC within the bulk gases was performed on the optical-access engine. Furthermore, studies were performed in order to ascertain whether the piston top-land crevice volume contributes significantly to engine-out HC emissions. Finally, the role of piston-top fuel films and their impact on HC emissions was studied. This was investigated on the all-metal engine using two fuels of different volatilities. Parallel studies were also performed on the optical-access engine via in-cylinder tracer laser-induced fluorescence (LIF) imaging.
Results obtained in the standard and optical access engines revealed that bulk quenching represents one of the most significant sources of unburned HC for the wall guided combustion chamber geometry. Bulk quenching occurs as a result of incomplete fuel oxidation reactions in regions where the local equivalence ratio is either too fuel-lean or too fuel-rich or alternatively in excessively low temperature zones within the combustion chamber. Experimental data obtained from both the standard and optical access engines also revealed that liquid film formation occurs, and is particularly prevalent for early start of injection (SOI) strategies. Furthermore, liquid films remain present at the end of combustion and are believed to represent a significant source of engine-out HC emissions. In-cylinder imaging of liquid films suggest that the film eventually detaches from the piston surface later during the expansion stroke, resembling a flash boiling phenomenon. The results appear to confirm that unburned fuel arising from piston-top fuel films contribute directly to the engine-out HC emissions.
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Kashdan, J., Mendez, S., and Bruneaux, G., "On the origin of Unburned Hydrocarbon Emissions in a Wall Guided, Low NOx Diesel Combustion System," SAE Technical Paper 2007-01-1836, 2007, https://doi.org/10.4271/2007-01-1836.Also In
References
- Christensen, M. Johansson, B. Hultqvist, A. 2001 “The Effect of Piston Topland Geometry on Emissions of Unburned Hydrocarbons from a Homogeneous Charge compression Ignition (HCCI) Engine” SAE technical paper, 2001-01-1893
- Aceves, S. M. Flowers, D. L. Espinoza-Loza, F. Martinez-Frias, J. Dibble, R. W. Christensen, M. Johansson, B. Hessel, R. P. 2002 “Piston-Liner Crevice Geometry Effect on HCCI Combustion by Multi-Zone Analysis” SAE technical paper, 2002-01-2869
- Heywood, J. B. “ Internal Combustion Engine Fundamentals ” McGraw-Hill New York 1988
- Iida, M. Hayashi, M. Foster, D. E. Martin, J. K. 2003 “Characteristics of Homogeneous Charge Compression Ignition (HCCI) Engine Operation for Variations in Compression Ratio, Speed and Intake Temperature while using n-Butane as a Fuel” Trans. ASME 125 472 478 April 2003
- Kook, S. Bae, C. Miles, P. C. Choi, D. Pickett, L. M. 2005 “The Influence of Charge Dilution and Injection Timing on Low-Temperature Diesel Combustion and Emissions” SAE technical paper 2005-01-3837
- Kook, S. Bae, C. Miles, P. C. Choi, D. Bergin, M. Reitz, R. D. 2006 “The Effect of Swirl Ratio and Fuel Injection Parameters on CO Emission and Fuel Conversion Efficiency for High-Dilution, Low-Temperature Combustion in an Automotive Diesel Engine” SAE technical paper 2006-01-0197
- Kashdan, J.T. Docquier, N. Bruneaux, G. 2004 “Mixture Preparation and Combustion via LIEF and LIF of Combustion Radicals in a Direct-Injection, HCCI Diesel Engine” SAE technical paper, 2004-01-2945
- Walter, B. Gatellier, B. 2002 “Development of the High Power NADI Concept Using Dual Mode Diesel Combustion to Achieve Zero NOx and Particulate Emissions” SAE technical paper, 2002-01-1744
- Siebers, D. L. 1998 “Liquid-Phase Fuel Penetration in Diesel Sprays” SAE technical paper, 980809
- Siebers, D. L. 1999 “Scaling Liquid-Phase Fuel Penetration in Diesel Sprays Based on Mixing-Limited Vaporization” SAE technical paper, 1999-01-0528
- Kimura, S. Aoki, O. Kitahara, Y. Aiyoshizawa, E. 2001 “Ultra-Clean Combustion Technology Combining a Low-Temperature and Premixed Combustion Concept For Meeting Future Emissions Standards” SAE technical paper, 2001-01-0200
- Lachaux, T. Musculus, M. P. B. 2006 “In-Cylinder Unburned Hydrocarbon Visualisation During Low-Temperature Compression-Ignition Engine Combustion Using Formaldehyde PLIF” Proc. 31 st Combustion Symp. 2006 Heidelberg, Germany 6-11 August 2006
- Kashdan, J. T. Papagni, J-F. 2005 “LIF Imaging of Auto-Ignition and Combustion in a Direct-Injection Diesel-Fuelled, HCCI Engine” SAE technical paper, 2005-01-3739
- Schulz, C. Gronki, J. Andersson, S. 2004 “Multi-Species Laser-Based Imaging Measurements in a Diesel Spray” SAE technical paper, 2004-01-1917
- Bruneaux, G. 2007 “Study of the Correlation Between Mixing and Auto-ignition Processes in High Pressure Diesel Jets” SAE technical paper, 2007-01-0650
- Sjöberg, M. Dec, J. E. Babjimopoulos, A. Assanis, D. 2004 “Comparing Enhanced Natural Thermal Stratification against Retarded Combustion Phasing for Smoothing of HCCI Heat-Release Rates” SAE technical paper, 2004-01-2994
- Dec, J. E. Hwang, W. Sjöberg, M. 2006 “An Investigation of Thermal Stratification in HCCI Engines using Chemiluminescence Imaging” SAE technical paper, 2006-01-1518
- Stevens, E. Steeper, R. 2001 “Piston Wetting in an Optical DISI Engine: Fuel Films, Pool Fires and Soot Generation” SAE technical paper, 2001-01-1203
- Witze, P. O. Green, R. M. 1997 “LIF and Flame-Emission Imaging of Liquid Fuel Films and Pool Fires in an SI Engine During a Simulated Cold Start” SAE technical paper, 970866
- Witze, P. O. Green, R. M. 2005 “Comparison of Single and Dual Spray Fuel Injectors During Cold Start of a PFI Spark-Ignition Engine Using Visualization of Liquid Fuel Films and Pool Fires” SAE technical paper, 2005-01-3863
- Dec, J. E. 2002 A Computational Study of the Effects of Low Fuel Loading and EGR on Heat Release Rates and Combustion Limits in HCCI Engines” SAE technical paper 2002-01-1309
- Dec, J. E. Sjöberg, M. 2003 “A Parametric Study of HCCI Combustion - The Sources of Emissions at Low Loads and the Effects of GDI Fuel Injection” SAE technical paper 2003-01-0752
- Marriott, C. D. Reitz, R. D. 2002 “Experimental Investigation of Direct Injection Gasoline for Premixed Compression Ignited Combustion Phasing Control” SAE technical paper 2002-01-0418