Optimizing the Roof Type Combustion Chamber Design of a Single-Cylinder, Four-Stroke Scooter Engine with Four Valves
| Autor: | ZHI-HAO YANG, 楊智皓 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 The in-cylinder flow characteristics of a single-cylinder, four-stroke motorcycle engine, which would affect the mixing and combustion performance were studied. A commercial engine with a displacement of 125cc was used as the benckmakr which was hereafdter called the “original engine.” Analyzed by the commercial computational fluid dynamic (CFD) software (Converge), the in-cylinder flow characteristics, such as the flow evolution patterns, turbulence kineytic energy (TKE), tumble ratio, were obtained. The effects of the parameters induced by the geometric arrangement of the engine combustion chamber, such as the volumetric efficiency and squish, were specifically studied. The angle of pent roof and the shape of the piston head which may significantly affect the in-cylinder flow characteristics were varied to examine the optimized designs for the combustion chamber. The engine spped and throttle opening were varied for the cases of study. The results showed that the pent roof angle at 22o to 23o may induce largest TKE and tumble ratio. The “original engne” had a pent roof angle of 22.9o which fell within the range of optimation design. A piston head with a slight concave or a slight convex of special designed geometries could increase tumble ratio up to about 10%. The variations of TKE and tumble ratio were almost unchanged under the conditions with and without installing the throttle value. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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