This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Emission Formation Mechanisms in a Two-Stroke Direct-Injection Engine
Annotation ability available
Sector:
Language:
English
Abstract
Engine tests were conducted to study the effect of fuel-air mixture preparation on the combustion and emission performance of a two-stroke direct-injection engine. The in-cylinder mixture distribution was altered by changing the injection system, injection timing, and by substituting the air in an air-assisted injector with nitrogen. Two injection systems which produce significantly different mixtures were investigated; an air-assisted injector with a highly atomized spray, and a single-fluid high pressure-swirl injector with a dense penetrating spray. The engine was operated at overall A/F ratios of 30:1, where stratification was necessary to ensure stable combustion; and at 20:1 and 15:1 where it was possible to operate in a nearly homogeneous mode. Moderate engine speeds and loads were investigated.
The effects of the burning-zone A/F ratio were isolated by using nitrogen as the working fluid in the air-assist injector. The burning-zone A/F ratio was found to be the most significant factor in the production of NOx due to both burning rate and phasing considerations which affected the thermal NOx production and also by chemical production mechanisms. The burning-zone A/F ratio was also found to impact the CO formation, predominately at retarded injection timings. The HC emissions were moderately affected by the burning-zone A/F ratio, and were also observed to result from overmixing of the spray, short-circuiting of the fuel, and poor combustion quality. Some evidence of anomalous injector behavior was detected in the HC and CO results.
Recommended Content
Technical Paper | The Axially-Stratified-Charge Engine |
Technical Paper | Development of a Fuel Injected Two-Stroke Gasoline Engine |
Technical Paper | The OCP Small Engine Fuel Injection System for Future Two-Stroke Marine Engines |
Citation
Casarella, M. and Ghandhi, J., "Emission Formation Mechanisms in a Two-Stroke Direct-Injection Engine," SAE Technical Paper 982697, 1998, https://doi.org/10.4271/982697.Also In
References
- EPA Regulation, Federal Register 61 194 October 1996
- Heywood, J. B. Internal Combustion Engine Fundamentals McGraw-Hill New York 1988
- Automotive Engineering December 1997 81 85
- Syvertsen, M. L. “Two-Stroke Direct-Injection Emissions and Efficiency: A Statistical Approach,” Department of Mechanical Engineering, University of Wisconsin - Madison 1996
- Syvertsen, M. L. et al. “Injection and Ignition Effects on Two-Stroke Direct-Injection Emissions and Efficiency,” SAE Paper 961803 1996
- Casarella, M. V. et al. “Spray Combustion and Emissions in a Direct-Injection Two Stroke Engine with Wall Stabilization of an Air-Assisted Spray,” SAE Paper 970360 1997
- Myers, J. et al. “On the Computation of Emissions from Exhaust Gas Composition Measurements,” Journal of Engineering for Gas Turbines and Power 111 410 1989
- Spindt, R. S. “Air-Fuel Ratios from Exhaust Gas Analysis,” SAE Paper 650507 1965
- Gatowski, J. A. et al. “Heat Release Analysis of Engine Pressure Data,” SAE Paper 841359 1984
- Hoffman, J. A. et al. “A Technique for Obtaining Spatial and Temporal Mass Flux Measurements of a Pulsed Spray: a Description of the Hardware and Methodology,” Rev. Sci. Instrum. 68 11 November 1997
- Hoffman, J. A. Martin J. K. “Mass-Related Properties of Atomizers for Direct-Injection SI Engines,” SAE Paper 980500 1998
- Coates, S. W. Lassanske, G. G. “Measurement and Analysis of Gaseous Exhaust Emissions from Recreational and Small Commercial Marine Craft,” SAE Paper 901596 1990
- Lancaster, D. R. “Diagnostic Investigation of Hydrocarbon Emissions from a Direct Injection Stratified Charge Engine with Early Injection,” Paper C397/80, I. Mech. E. Conference on Stratified Charge Automotive Engines 1980
- Frank, R. M. Heywood, J. B. “Combustion Characterization in a Direct-Injection Stratified-Charge Engine and Implications on Hydrocarbon Emissions,” SAE Paper 892058 1989
- Giovanetti, A. J. et al. “Analysis of Hydrocarbon Emissions Mechanisms in a direct-Injection Spark-Ignition Engine,” SAE Paper 830587 1983
- Drake, M. C. et al. “Advanced Diagnostics for Minimizing Hydrocarbon Emissions From a Direct-Injection Gasoline Engine,” Twenty-Sixth Symposium (International) on Combustion The Combustion Institute 1996
- Fansler, T. D. et al. “Individual-Cycle Measurements of Exhaust-Hydrocarbon Mass from a Direct-Injection Two-Stroke Engine,” SAE Paper 980758 1998
- Drake, M. C. et al. “Fuel Distributions in a Firing Direct-Injection Spark-Ignited Engine Using Laser-Induced Fluorescence Imaging,” SAE Paper 950110 1995
- Turns, S. R. An Introduction to Combustion, Concepts and Applications McGraw-Hill New York 1996
- Frank, R. M. Heywood, J. B. “The Importance of Injection System Characteristics on Hydrocarbon Emissions from a Direct-Injection Stratified-Charge Engine,” SAE Paper 900609 1990
- Frank, R. M. Heywood, J. B. “The Effect of Piston Temperature on Hydrocarbon Emissions from a Spark-Ignited Direct-Injection Engine,” SAE Paper 910558 1991
- Ingham, M. et al. “In-cylinder Sampling of Hydrocarbons in a Texaco L-141 TCP Engine,” SAE Paper 820361 1982
- Kim, C. Foster, D. E. “Aldehyde and Unburned Fuel Emissions Measurements from a Methanol-Fueled Texaco Stratified Charge Engine,” SAE 852120 1985
- Kollman, R. E. et al. “Exhaust Emission Characteristics of a Small 2-Stroke Cycle Spark Ignition Engine,” SAE Paper 730159 1973
- Yoon, K. et al. “An Experimental comparison Between Air-Assisted Injection System and High Pressure Injection System at 2-Stroke Engine,” SAE Paper 950270 1995
- Eng, j. A. et al. “experimental hydrocarbon Consumption Rate Correlations from a spark ignition Engine,” SAE Paper 972888
- Drake, M. C. et al. “Crevice Flow and Combustion Visualization in a Direct-Injection Spark-ignition Engine Using Laser Imaging Techniques,” SAE Paper 952454 1995
- Linna, J.-R. Hochgreb, S. “Analytical Scaling Model for Hydrocarbon Emissions From Fuel Absorption in Oil Layers in Spark Ignition Engines,” Combust. Sci. and Tech. 109 205 226 1995
- Martin, J. K. et al. “Burn modes and Prior-Cycle Effects on Cyclic Variations in Lean-Burn Spark-Ignition Engine Combustion SAE Paper 880201 1988
- Parrish, S. E. Farrell, P. V. “Transient Spray Characteristics of a Direct-Injection Spark-Ignited Fuel Injector,” SAE 970629 1997
- Matekunas, F. A. “Modes and Measures of Cyclic Combustion Variability,” SAE Paper 830337 1983
- Fansler, T. D. et al. “Individual-Cycle Measurements of Exhaust-Hydrocarbon Mass for a Direct-Injection Two-Stroke Engine,” SAE Paper 980758 1998