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The Always Lean Burn Spark Ignition (ALSI) Engine – Its Performance and Emissions
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 20, 2009 by SAE International in United States
Annotation ability available
This paper is based on extensive experimental research with lean burn, high compression ratio engines using LPG, CNG and gasoline fuels. It also builds on recent experience with highly boosted spark ignition gasoline and LPG engines and single cylinder engine research used for model calibration. The final experimental foundation is an evaluation of jet assisted ignition that generally allows a lean mixture shift of more than one unit in lambda with consequential benefits of improved thermal efficiency and close to zero NOx.
The capability of an ultra lean burn spark ignition engine is described. The concept is operation at air-fuel ratios similar to the diesel engine but with essentially homogenous charge, although some stratification may be desirable. To achieve high thermal efficiency this engine has optimized compression ratio but with variable valve timing which enables reduction in the effective compression ratio when desirable. High specific power output is achieved by supercharging the engine and no NOx reduction is proposed with only an oxidation catalyst needed to meet Euro 6 standards.
The 2.6L four-cylinder engine is optimized using the group's PSO (particle swarm optimizer) and a first order engine simulation model that at a particular torque-speed, can rapidly find the local optimum engine configuration. It has been shown that the model accurately predicts the performance for all air-fuel ratios to the lean limit of both normal spark ignition and jet assisted ignition with LPG and other fuels.
Mechanical constraints of the four valve pent roof combustion chamber limit the compression ratio to 15 or to lower values because of knock or excessive friction losses. Variable cam phasing is essential and the performance of variable inlet valve duration and fixed inlet valve duration cams are compared. In addition to power, thermal efficiency, and NOx emissions, operational characteristics of the engine are reported: optimum ignition timing, lambda, cam-phasing, boost/throttle and more.
The engine's predicted maximum performance is a torque of 283 Nm and power of 150 kW with a fuel consumption reduction of around 40% over conventional SI. This prediction is based on hot-start steady state data so real engine performance will likely be less.
CitationWatson, H., Mehrani, P., and Brear, M., "The Always Lean Burn Spark Ignition (ALSI) Engine – Its Performance and Emissions," SAE Technical Paper 2009-01-0932, 2009, https://doi.org/10.4271/2009-01-0932.
- Watson H.C. Kumar S. Kyaw Z.H. Reduction of cyclic variability and lean limit operation of alternative fuels by pilot hydrogen in unmodified SI engines Proc. Eighth World Hydrogen Energy Conference Honolulu, Waikoloa 1990
- Kyaw Z.H. Watson H.C. ‘Hydrogen assisted jet ignition for near elimination of NOx and cyclic variability in the s.i. engine’ Proceedings of the 24th International Symposium on Combustion Sydney 1 25 1992
- Lumsden G. Watson H.C. Optimum control of an S.I. engine with a • = 5 capability SAE paper 950689 1995
- Glasson N. Lumsden G. Dingli R. Watson H.C. Development of the HAJI System for a multi-cylinder spark ignition engine SAE paper 961104 P1-10 1996
- Lawrence J. Hydrocarbon Emissions from a HAJI Equipped Ultra Lean Burn Engine University of Melbourne Phd Thesis Parkville, Melbourne, Australia 1999
- Dober G. Geometric Control of HC emissions The University of Melbourne PhD Thesis Parkville, Melbourne, Australia 2002
- Watson H.C. Karim G.A. Experimental and analytical consideration of the compression ignition of fuel-oxidant mixtures Trans. S.A.E. Paper No. 710133 361 373 1971
- Watson H.C. Milkins E.E. Deslandes J. The prediction and measurement of emissions, performance and efficiency of an homogeneous compression ignition engine Inst. Eng. Aust. Thermofluids Conf. Proc. 35 45 1974
- Watson H.C. Milkins E.E. Goldsworthy L.C. Optimising the spark ignition pre-chamber geometry including spark plug configuration for minimum NOx emissions and maximum efficiency Proc. XIX FISITA Congress SAE Australasia 13.1 13.7 1982
- Watson H.C. Kumar S. Kyaw Z.H. Reduction of cyclic variability and lean limit operation of alternative fuels by pilot hydrogen in unmodified SI engines Proc. Eight World Hydrogen Energy Conference Honolulu, Waikoloa 1990
- Watson H.C. Milkins E.E. Some problems and benefits from the hydrogen fuelled spark ignition engine Proc. 13th IECEC, 2 SAE paper 789212 1170 1177 1978
- Maxson J.A. Oppenheim A.K. Pulsed jet combustion--key to a refinement of the stratified charge concept Twenty-Third Symposium (International) on Combustion The Combustion Institute 1041 1046 1990
- Gussak L.A. High chemical activity of incomplete combustion products and a method of prechamber torch ignition for avalanche activation of combustion in internal combustion engines SAE Trans. 84 2421 2445 1975
- Kyaw Z.H. Watson H.C. Hydrogen assisted jet ignition for near elimination of NOx and cyclic variability in the s.i. engine Proceedings of the 24th International Symposium on Combustion Sydney 1 25 1992
- Mehrani P. Predicting knock in a HAJI engine PhD Thesis University of Melbourne 2008
- Toulson E. Watson H. Attard W The Effects of Hot and Cool EGR with Hydrogen Assisted Jet Ignition SAE paper 2007-01-3627 2007
- Toulson E. Applying alternative fuels in place of hydrogen to the jet ignition process PhD. Thesis University of Melbourne 2008
- Ratnaweera Asanga Halgamuge Saman K. Watson H.C. Enhanced IC SI Engine Performance With Particle Swarm Optimization SAE paper 2004-28-0075 2004
- Watson H.C. Mehrani P A search for maximum efficiency and NOx reduction through spark-ignition engine design optimization at lambda = 1.proc. IMechE Vol 222 Part D Journal of Automobile Design Engineering 2008
- Watson H.C. Mehrani P Joint Efficiency and NOx Optimization Using a PSO Algorithm SAE paper 2006-01-1109 2006
- Watson H.C. Mehrani P. Modeling the Effect of Mixture Composition on Cyclic Variability SAE paper 2007-01 -0672 2007
- Watson H.C. Mehrani P. Optimized Design of a Cyclic Variability Constrained Lean Limit SI Engine at Optimum NOx and Efficiency Using a PSO Algorithm SAE paper 2007-01-3551 2007
- Watson H.C. Opportunities for Making LPG a Clean and Low Greenhouse Emission Fuel SAE paper 2005-01 -2217 2005
- Watson H.C. Baker P.A. MPI Air/Fuel Mixing for Gaseous and Liquid LPG SAE paper 2005-01-0246 2005
- Watson H.C. Baker P.A Khan M. A. Liew g Johnston D. SI Engine Lean-Limit Extension Through LPG Throttle-Body Injection for Low CO2 and NOx SAE paper 2006-01-0495 2006
- Zakis G. Watson H.C. Lean Mixture Ignition Systems for CNG in Diesel Applications SAE paper 2004-28-0017 2004
- Wang D.E. Watson H.C Reducing HC emissions with Direct Injection of Natural Gas in a Hydrogen Assisted Jet Ignition Engine IFP Conference Which Fuels For Low CO2 Engines? Paris June, 2003
- Rosenkranz H.G. Watson H.C. Bryce W. Lewis A. Driveability fuel consumption and emissions of 1.3 litre turbocharger spark ignition engine developed as a replacement for a 2 litre normally aspirated engine Proc. I.Mech.E., C118/86:139-150 1986
- Watson H.C. William Attard Konidaris Steven Highly Turbocharging a Flow Restricted Two Cylinder Small Engine - Turbocharger Development SAE paper 2007-01 - 1562 2007
- Hamori F. Optimising the application of HAJI to the supercharged engine University of Melbourne Phd Thesis Parkville, Melbourne, Australia 2004
- Watson H.C. Khan Mohammad Ali William Attard Konidaris Steven Comparing the Performance and Limitations of a Downsized Formula SAE Engine in Normally Aspirated, Supercharged and Turbocharged Modes 2006-32-0072 2006
- Watson H.C. Milkins E.E. Preston M.O. Chittleborough C. Alimoradian B. Predicting fuel consumption and emissions - transferring chassis dynamometer results to real driving conditions SAE paper 830435 1983
- Watson H.C. Effects of a wide range of drive cycles on the emissions from vehicles of three levels of technology Global Emissions Experiences SAE Warrendale, Pa., USA SP-1094 119 132 0148-7191 1995
- Mehrani P. Watson H.C. “Modeling the Effect of Mixture Composition on Cyclic Variability” SAE paper 2007-01-0672 2007
- Mehrani P. Watson H.C. “Joint Efficiency and NOx Optimization Using a PSO Algorithm” 2006-01 -1109 World Congress 2006
- Das A. Watson H.C. Development of a natural gas spark ignition engine for optimum performance Proc. IMechE, Vol 211, Part D, D00496 1997
- Kume T. Iwamoto Y. Combustion control technologies for direct injection SI engine SAE Paper 960600 1996
- Zhao F. Lai M. Harrington D. Automotive spark-ignition direct-injection gasoline engines Progress of Energy and Combustion Science 25 03601285 437 562 1999
- Maricq M. Munoz R. Yang J. Anderson R. Sooting tendencies in an air-forced direct injection spark-ignition DISI engine SAE Paper 2000-01-0255 2000
- Carlisle H. Watson H. C. Bryce W. Brear M. J. Boretti A. A. Attard W. Jin S. H. Zakis G. Experimental and Theoretical Study of an Air Assisted Fuel Injector for a D.I.S.I. Engine SAE paper 007-01-1415 2007