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Fast Response Measurement of Combustion Air to Fuel Ratio for Stratified Two-Stroke Engines
Published October 12, 2005 by Society of Automotive Engineers of Japan in Japan
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Due to emission regulations for hand-held power tools more and more stratified-charge two-stroke engines enter into the market [Sawada et al. 1998, Zahn et al. 2000]. These engines require investigations and treatment for tuning the transient behaviour that are beyond the methods of the tuning for conventional engines. Especially the in-cylinder air-to-fuel-ratio cannot be determined from simple exhaust gas analysis any more.
This paper presents an exhaust gas sampling system to enable the use of a standard lambda meter for a fast response measurement of air to fuel ratio out of the combustion chamber. The gas is sampled by means of a small restriction directly out of the combustion chamber. In case of miss-fire the hydrocarbon concentration in the sample is too high for the lambda sensor. With a dilution or a pre-converter system the hydrocarbon concentration can be adjusted to the range of the lambda sensor. Verification has been done with several tests.
The air to fuel ratio in combustion is a key issue to tune the transient behaviour and to meet all customer requirements of the engine performance.
CitationGEYER, K., HALLÉ, C., and ROßKAMP, H., "Fast Response Measurement of Combustion Air to Fuel Ratio for Stratified Two-Stroke Engines," SAE Technical Paper 2005-32-0109, 2005.
- Blair, G. P. Design and Simulation of Two-Stroke Engines SAE 1-56091-685-0 1996
- Sawada, T. Wada, M. Development of a Low Emission Two-Stroke Cycle Engine SAE-Paper 980761 1998
- Zahn, W. Rosskamp, H. Schlossarczyk, J. Low Emission Technologies for High-Performance Handheld Outdoor Products SAE-Paper 2000-01-0896 2000