This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Effect of Early-Closing of Intake-Valve on the Engine Performance in a Spark-Ignition Engine
Annotation ability available
Sector:
Language:
English
Abstract
The objective of the present study is to clarify the effect of early-closing of an intake-valve on the engine performance in a spark-ignition engine. For the first step of the study, under natural aspirating condition, four sets of expansion ratio pistons of 11, 16, 20 and 22 were prepared for two kinds of camshaft, one is, original and the other is geometrically half early-closing.. The obtained performance data and the indicator pressure records were analyzed. It was shown that up to 7 % of improvement in the thermal efficiency can be realized over a wide range of operating condition. This is considered to be mainly caused by the effect of the increased-expansion cycle. The increased-expansion effect can be estimated to be about 1.4 which almost corresponds to the geometrical inlet-valve closure timing. However, this value is not consistent with the measured volumetric efficiency which was almost half the value associated with original timing. This inconsistency is discussed, and the increase of the residual gas fraction is suggested to be the main reason for it. This suggestion was verified qualitatively by a combustion analysis using a two-zone heat release model.
Recommended Content
Authors
Citation
Shiga, S., Nakamura, H., Karasawa, T., Yagi, S. et al., "Effect of Early-Closing of Intake-Valve on the Engine Performance in a Spark-Ignition Engine," SAE Technical Paper 960585, 1996, https://doi.org/10.4271/960585.Also In
References
- Horie, K. et al SAE Paper, No. 920455 1992
- Yagi, S. et al SAE Paper, No. 920450 1992
- Taylor, C.F. The Internal-Combustion Engine in Theory and Practice II The M.I.T. Press 1979 403
- Heywood, J.B. Internal Combustion Engine Fundamentals McGraw-Hill Book Co. 1988 183
- Tuttle, J.H. SAE Paper, No. 800794 1980
- Woschni, G. SAE Paper, No. 670931 1967