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HCCI Combustion - Engine Operation and Emission Characteristics

Christensen, Magnus LU (2002)
Abstract
The potential and limitations of the Homogeneous Charge Compression Ignition (HCCI) engine concept has been experimentally investigated. The operation range, in terms of usable air/fuel ratio and engine load, and the emission characteristics have been studied. An 1.6 litre single cylinder engine based on a heavy duty six cylinder Volvo, was used for the tests. As follows the experimental work was limited to study HCCI combustion at low speed operation in a heavy duty sized engine.



The HCCI combustion process is very different compared to the Spark Ignition and Compression Ignition (Diesel) combustion processes. HCCI lacks normal flame propagation, instead the entire charge is gradually consumed in a non-flame mode almost... (More)
The potential and limitations of the Homogeneous Charge Compression Ignition (HCCI) engine concept has been experimentally investigated. The operation range, in terms of usable air/fuel ratio and engine load, and the emission characteristics have been studied. An 1.6 litre single cylinder engine based on a heavy duty six cylinder Volvo, was used for the tests. As follows the experimental work was limited to study HCCI combustion at low speed operation in a heavy duty sized engine.



The HCCI combustion process is very different compared to the Spark Ignition and Compression Ignition (Diesel) combustion processes. HCCI lacks normal flame propagation, instead the entire charge is gradually consumed in a non-flame mode almost at the same time. As almost the entire charge is involved in the combustion process at the same time, the global heat release rate is primary determined by the local heat release rate. This means that the heat release rate is controlled by the grade of charge dilution. Normally, the entire charge is consumed in 5 – 20 crank angle degrees.



Due to its nature, HCCI has the potential to generate very low emissions of nitrogen oxides (NOx). It is possible to operate the engine with almost zero NOx. The reason for the low NOx potential is that the HCCI concept has the capability to use ultra lean premixed mixtures, resulting in a low and uniform combustion temperature in the combustion chamber.



The emissions of unburned hydrocarbons (HC) proved to be two to three times higher compared to spark ignition operation for a given engine load. The main source of unburned hydrocarbons are crevices, primary the piston topland crevice. Wall effects and bulk quenching proved to be less important. If the total crevice volume is minimized and the engine is operated rich enough, say below lambda = 2.5, very low HC levels are possible to obtain.



The emission of carbon monoxide (CO) is very dependent on the temperature history during the combustion period. Close to the rich limit and/or with early timing, CO is quite low, lower than for SI operation.



HCCI combustion can be considered as smokeless when using high volatility fuels (light fuels like gasoline). With heavier fuels, like diesel fuel, smoke is very sensitive to the mixture preparation. With port injection of diesel fuel very much smoke was generated in some cases. The combination of low charge temperature and port injection of diesel fuel, resulted in smoke levels of 1 – 4 BSN units.



The HCCI engine concept has superior potential for achieving high part load fuel conversion efficiency. This is due to the combination of small pumping losses, high compression ratio and short combustion period. With the present test engine, the best obtained indicated efficiency at part load conditions was about 45 %.



The requirement of highly diluted mixtures limits the attainable engine load. With the present test engine the maximum IMEP was around 5 bar at unthrottled operation (naturally aspirated). However, by applying supercharging via an external air compressor, 16 bar of IMEP has been obtained.



Besides the limited power density, the lack of direct ignition timing control is maybe the major disadvantage of the HCCI concept. A feedback signal from some sort of combustion sensor is necessary in order to contol the ignition timing via an indirect method. Possible control strategies are through Variable Compression Ratio (VCR), dual fuels or internal EGR.



Turbulence and combustion chamber geometry proved to play an important role for HCCI combustion. Higher turbulence resultet in reduced heat release rate. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Duret, Pierre, IFP, France
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Motorer, framdrivningssystem, Motors and propulsion systems, efficiency, emissions, combustion, HCCI, engine
pages
350 pages
publisher
Department of Heat and Power Engineering, Lund university
defense location
M:B in M-building
defense date
2002-11-28 10:15:00
ISBN
91-628-5424-0
language
English
LU publication?
yes
additional info
Article: Paper 1.Homogeneous Charge Compression Ignition (HCCI) Using Iso-octane, Ethanol andNatural Gas – A Comparison with Spark Ignition OperationSAE paper 972874By Magnus Christensen, Patrik Einewall and Bengt JohanssonPresented by Bengt Johansson at the SAE Fall Fuel & Lubricants, Tulsa, Oklahoma,October 13-16, 1997Approved for SAE Transactions 1997. Article: Paper 2.Supercharged Homogeneous Charge Compression IgnitionSAE paper 980787By Magnus Christensen and Bengt Johansson, Per Amnéus and Fabian MaussPresented by the author at the SAE International Congress and Exposition, Detroit, Michigan, February 23-26, 1998Approved for SAE Transactions 1998. Article: Paper 3.Homogeneous Charge Compression Ignition Engine: Experiments and Detailed Kinetic CalculationsBy Per Amnéus, Daniel Nilsson, Fabian Mauss, Magnus Christensen and Bengt JohanssonPresented by Per Amnéus at the Fourth International Symposium on Diagnostic and Modeling in Internal Combustion Engines, Comodia 98, July 20-23, 1998 Article: Paper 4.Influence of Mixture Quality on Homogeneous Charge Compression IgnitionSAE paper 982454By Magnus Christensen and Bengt JohanssonPresented by the author at SAE Fall Fuels & Lubricants, San Francisco, California, October 19-22, 1998Approved for SAE Transactions 1998. Article: Paper 5.Homogeneous Charge Compression Ignition with Water InjectionSAE paper 1999-01-0182By Magnus Christensen and Bengt JohanssonPresented by the author at the SAE International Congress and Exposition, Detroit, Michigan, March 1-4, 1999 Article: Paper 6.Demonstrating the Multi Fuel Capability of a Homogeneous Charge Compression Ignition Engine with Variable Compression RatioSAE paper 1999-01-3679By Magnus Christensen, Anders Hultqvist and Bengt JohanssonPresented by the author at SAE Fall Fuels & Lubricants, Toronto, Ontario, Canada, October 25-28, 1999The paper was awarded with the Harry LeVan Horning Memorial Award for best SAE paper 1999. Article: Paper 7.A Study of the Homogeneous Charge Compression Ignition Combustion Process by Chemiluminescence ImagingSAE paper 1999-01-3680By Anders Hultqvist, Magnus Christensen, Bengt Johansson, Axel Franke, Mattias Richter and Marcus AldénPresented by the Anders Hultqvist at SAE Fall Fuels & Lubricants, Toronto, Ontario, Canada, October 25-28, 1999 Article: Paper 8.A Multi-Zone Model for Prediction of HCCI Combustion and EmissionsSAE paper 2000-01-0327By Salvador M. Aceves, Daniel L. Flowers, Charles K. Westbrook, J. Ray Smith and William Pitz, Robert Dibble, Magnus Christensen and Bengt JohanssonPresented by Salvador M. Aceves at the SAE International Congress and Exposition, Detroit, Michigan, March 6-9, 2000 Article: Paper 9.Supercharged Homogeneous Charge Compression Ignition (HCCI) with Exhaust Gas Recirculation and Pilot FuelSAE paper 2000-01-1835By Magnus Christensen and Bengt JohanssonPresented by the author at SAE Spring Fuels & Lubricants, Paris, France, June 19-22, 2000 Article: Paper 10.Modeling and Experiments of HCCI Engine Combustion Using Detailed Chemical Kinetics with Multidemensional CFDSAE paper 2001-01-1026By Song-Charng Kong, Craig D. Marroit, Rolf D. Reitz, Magnus ChristensenPresented by Rolf D. Reitz at the SAE International Congress and Exposition, Detroit, Michigan, March 1-4, 2001 Article: Paper 11.The Effect of Piston Topland Geometry on Emissions of Unburned Hydrocarbons from a Homogeneous Charge Compression Ignition (HCCI) EngineSAE paper 2001-01-1893By Magnus Christensen, Anders Hultqvist and Bengt JohanssonPresented by the author at SAE Spring Fuels & Lubricants, Orlando, Florida, May 7-9, 2001 Article: Paper 12.The Effect of Combustion Chamber Geometry on HCCI OperationSAE paper 2002-01-0425By Magnus Christensen, Anders Hultqvist and Bengt JohanssonPresented by the author at the SAE International Congress and Exposition, Detroit, Michigan, March 4-7, 2002 Article: Paper 13.Experimental and Simulated Results Detailing the Sensitivity of Natural Gas HCCI Engines to Fuel CompositionSAE paper 2001-01-3609By Scott B. Fiveland, Rey Agama, Magnus Christensen, Bengt Johansson, Joel Hiltner, Fabian Mauss, Dennis N. AssanisPublished at the SAE Fall Fuels & Lubricants, 2001Presented by Scott B. Fiveland at the SAE International Congress and Exposition, Detroit, Michigan, March 4-7, 2002 Article: Paper 14.The Effect of In-cylinder Flow and Turbulence on HCCI OperationSAE paper 2002-01-2864By Magnus Christensen and Bengt JohanssonPresented by Bengt johansson at the 2002 Powertrain & Fluid Systems Conference, San Diego, Texas, Oct 21-24, 2002 Article: Paper 15.Piston-Liner crevice Geometry Effect on HCCI Combustion by Multi-Zone AnalysisSAE paper 2002-01-2869By Salvador M. Aceves, Daniel L. Flowers, Francisco Espinosa-Loza, Joel Martinez-Frias, Robert W. Dibble, Magnus Christensen, Bengt Johansson, Randy HesselPublished at the 2002 Powertrain & Fluid Systems Conference, San Diego, Texas, Oct 21-24, 2002 Article: Paper 16.Modeling the Effects of Geometry Generated Turbulence on HCCI Engine CombustionSAE paper 2003-01-xxxxBy Song-Charng Kong, Rolf D. Reitz, Magnus Christensen, Bengt JohanssonSubmitted to the SAE International Conference & Exposition, Detroit, 2003
id
54be5281-c055-4f3a-8373-0f353a49b2c3 (old id 465252)
date added to LUP
2016-04-01 16:20:17
date last changed
2018-11-21 20:40:38
@phdthesis{54be5281-c055-4f3a-8373-0f353a49b2c3,
  abstract     = {The potential and limitations of the Homogeneous Charge Compression Ignition (HCCI) engine concept has been experimentally investigated. The operation range, in terms of usable air/fuel ratio and engine load, and the emission characteristics have been studied. An 1.6 litre single cylinder engine based on a heavy duty six cylinder Volvo, was used for the tests. As follows the experimental work was limited to study HCCI combustion at low speed operation in a heavy duty sized engine.<br/><br>
<br/><br>
The HCCI combustion process is very different compared to the Spark Ignition and Compression Ignition (Diesel) combustion processes. HCCI lacks normal flame propagation, instead the entire charge is gradually consumed in a non-flame mode almost at the same time. As almost the entire charge is involved in the combustion process at the same time, the global heat release rate is primary determined by the local heat release rate. This means that the heat release rate is controlled by the grade of charge dilution. Normally, the entire charge is consumed in 5 – 20 crank angle degrees.<br/><br>
<br/><br>
Due to its nature, HCCI has the potential to generate very low emissions of nitrogen oxides (NOx). It is possible to operate the engine with almost zero NOx. The reason for the low NOx potential is that the HCCI concept has the capability to use ultra lean premixed mixtures, resulting in a low and uniform combustion temperature in the combustion chamber.<br/><br>
<br/><br>
The emissions of unburned hydrocarbons (HC) proved to be two to three times higher compared to spark ignition operation for a given engine load. The main source of unburned hydrocarbons are crevices, primary the piston topland crevice. Wall effects and bulk quenching proved to be less important. If the total crevice volume is minimized and the engine is operated rich enough, say below lambda = 2.5, very low HC levels are possible to obtain.<br/><br>
<br/><br>
The emission of carbon monoxide (CO) is very dependent on the temperature history during the combustion period. Close to the rich limit and/or with early timing, CO is quite low, lower than for SI operation.<br/><br>
<br/><br>
HCCI combustion can be considered as smokeless when using high volatility fuels (light fuels like gasoline). With heavier fuels, like diesel fuel, smoke is very sensitive to the mixture preparation. With port injection of diesel fuel very much smoke was generated in some cases. The combination of low charge temperature and port injection of diesel fuel, resulted in smoke levels of 1 – 4 BSN units.<br/><br>
<br/><br>
The HCCI engine concept has superior potential for achieving high part load fuel conversion efficiency. This is due to the combination of small pumping losses, high compression ratio and short combustion period. With the present test engine, the best obtained indicated efficiency at part load conditions was about 45 %.<br/><br>
<br/><br>
The requirement of highly diluted mixtures limits the attainable engine load. With the present test engine the maximum IMEP was around 5 bar at unthrottled operation (naturally aspirated). However, by applying supercharging via an external air compressor, 16 bar of IMEP has been obtained.<br/><br>
<br/><br>
Besides the limited power density, the lack of direct ignition timing control is maybe the major disadvantage of the HCCI concept. A feedback signal from some sort of combustion sensor is necessary in order to contol the ignition timing via an indirect method. Possible control strategies are through Variable Compression Ratio (VCR), dual fuels or internal EGR.<br/><br>
<br/><br>
Turbulence and combustion chamber geometry proved to play an important role for HCCI combustion. Higher turbulence resultet in reduced heat release rate.},
  author       = {Christensen, Magnus},
  isbn         = {91-628-5424-0},
  language     = {eng},
  publisher    = {Department of Heat and Power Engineering, Lund university},
  school       = {Lund University},
  title        = {HCCI Combustion - Engine Operation and Emission Characteristics},
  year         = {2002},
}