This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Numerical Analysis of an Air-Head Stratified Scavenging Concept for Emission Reduction of a Two-Stroke Engine
Technical Paper
2001-24-0051
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Small two-stroke engines enjoy wide-spread acceptance in the field of hand-held outdoor equipment due to performance advantages over competing technologies. The main issue with these engines is their high hydrocarbon emission, which makes it difficult to comply with future emission laws such as the 2005 standards for small handheld engines of the U.S. Environmental Protection Agency (EPA). As a result, considerable research and development work is currently being carried out both in industrial and public research facilities to improve the hydrocarbon emission performance of two-stroke engines. Major emission reductions are expected from stratified scavenging concepts. However, the development and tuning of stratified scavenging engines requires comprehensive knowledge of the flow processes in the ports and inside the engine cylinder. Therefore, the investigation presented in this paper aims at the analysis of the three-dimensional displacement and mixing processes inside the transfer ports and the cylinder of an EPA-Class IV two-port two-stroke engine for research purposes featuring an air-head stratified scavenging concept. The approach applied was a detailed 3D flow simulation based on boundary conditions gained from one-dimensional calculations. A special evaluation method was developed which allows the analysis of the principal hydrocarbon loss mechanisms. The effect of air-head scavenging was investigated by comparison to a calculation without stratification. The numerical calculations performed at three different engine speeds showed good agreement with the experimental results. Starting from the original configuration, further investigations were carried out in order to analyse the potential and limitations of this concept. For this purpose, additional numerical calculations were performed assuming improved stratification and increased air-head mass. The results of these calculations lead to new approaches for further development in order to meet future hydrocarbon emission limits.
Recommended Content
Authors
Citation
Günthner, M., Mugele, M., Tribulowski, J., Spicher, U. et al., "Numerical Analysis of an Air-Head Stratified Scavenging Concept for Emission Reduction of a Two-Stroke Engine," SAE Technical Paper 2001-24-0051, 2001, https://doi.org/10.4271/2001-24-0051.Also In
References
- “Final Phase 2 Standards for Spark-Ignition Handheld Engines”
- Zahn, W. Rosskamp, H. Schlossarczyk, J. “Low Emission Technologies for High-Performance Handheld Outdoor Products” SAE 2000-01-0896
- Nuti, M. Caponi, D. “Direct Injection: The most Effective Way for Emission Reduction in Small 2T S.I. Engines” Proceedings 4 th International Conference “Internal Combustion Engines”, Open Workshop “2-Stroke Engines” Naples 1999
- Cobb, B. “CWI – Low cost fuel injection for two-stroke engines” Internationale Jahrestagung für die Entwicklung von Kleinmotoren (International Annual Conference on Two-Stroke Engine Development) Offenburg/Germany 2001
- Blair, G.P. “Design and Simulation of Two-Stroke Engines” Society of Automotive Engineers 1996
- Lanchester, F.W. Pearsall, R.H. “An Investigation into Certain Aspects of the Two-Stroke Engine for Automobile Vehicles” The Automobile Engineer, London Feb. 1922
- Cunningham, G. Kee, R.J. Kenny, R.G. Skelton, W.J. “Development of a Stratified Scavenging System for Small Capacity Two-Stroke Engines” SAE 1999-01-3270 /JSAE 9938025
- Saxena, M. Mathur, H.B. Radzimirski, S. “A Stratified Charging Two-Stroke Engine for Reduction of Scavenged-Through Losses” SAE 891805
- Yoshida, Y. Uenoyama, K. Kawahara, Y. Kudo, K. “Development of Stratified Scavenging Two-Stroke Cycle Engine for Emission Reduction” SAE 1999-01-3269 /JSAE 9938024