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Application of Exhaust Pipe Restriction Technique to a Small Two-Stroke Engine
Technical Paper
2007-32-0032
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English
Abstract
A simple method to reduce HC emissions caused by fuel short-circuiting in a two-stroke engine is to apply a certain restriction to the exhaust gas flow in the exhaust pipe. This technique, developed for motorcycles, vehicles and outboards, has been applied to a small off-road two-stroke engine with a constant speed operating condition. In order to assess the feasibility and effectiveness of this technique for the reduction of HC and CO emissions in such an engine, a butterfly valve was installed in the exhaust pipe next to the exhaust port. Based on test results using the butterfly valve, a cylindrical restrictor was developed to generate various restrictions to the gas flow in the exhaust pipe and consequently reduce the fuel short-circuiting. The effectiveness of the restrictor on emission reduction was further improved by leaner air/fuel mixture. The experimental results showed improved engine performance including the best 24% reduction of total weighted HC and 25% reduction of total weighted CO when the exhaust pipe restriction was 50%. Additionally, Mota, a two-stroke engine simulation program, was used to simulate the engine performance with reduced diameter of the exhaust pipe. The outcomes of this simulation support and explain the experimental results.
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Citation
Watson, F. and Hong, G., "Application of Exhaust Pipe Restriction Technique to a Small Two-Stroke Engine," SAE Technical Paper 2007-32-0032, 2007.Also In
References
- Tsuchiya, K. Hirano, S. Gotoh, O.T. “Emission control of two-stroke motorcycle engines by the butterfly exhaust valve” SAE paper 800973 1980
- Sher, E. Refael, H. S. Harari, R. “Minimizing short-circuiting losses in 2-S engines by throttling the exhaust pipe” SAE paper 901665 1990
- Ishibashi, Y. “A trail for stabilizing combustion in two stroke engines at part throttle operation” A New Generation of Two-Stroke Engines for the Future? Duret P. Editions Technip Paris 113 124 1993
- Asai, M. Kurosaki, T. Okada, K. “Analysis on fuel economy improvement and exhaust emission reduction in a two-stroke engine by using an exhaust valve” SAE paper 951764 1995
- Ishibashi, Y. Asai, M. “Improving the exhaust emission of two-stroke engines by applying the activated radical combustion” SAE paper 960742 1996
- Idhibashi, Y. Asai, M. “A low pressure pneumatic direct injection two-stroke engine by activated radical combustion concept” SAE 980757 1998
- Ishibashi, Y. “Basic understanding of activated radical combustion and its two-stroke engine application and benefits” SAE paper 2000-01-1836 2000
- Ishibashi, Y. Sakuyama, H. “An application study of the pneumatic direct injection activated radical combustion two-stroke engine scooter” SAE paper 2004-01-1870 2004
- Blair, Gordon P. Design and simulation of Two-stroke engines SAE Inc. 1996
- Council of the European Union “Directive 2002/88/EC of the European Parliament and of the Council of 9 December 2002” Official Journal of the European Union 11 February 2003
- van Leersum, J. “A numerical model of a high performance two-stroke engine” Applied Numerical Mathematics 27 1998 83 108