Optimization study is performed for the scavenging process as the first step for the development of a poppet-valve type automotive two-stroke diesel engine. The scavenging flow pattern is varied by the RSSV (rotatable shrouded scavenging valve) system, which was designed for application of a shroud valve to an actual engine. The scavenging flow is analyzed by flow visualization and numerical calculations under a steady condition. Water is used as the working fluid, instead of air for effective visualization of the flow pattern in the flow visualization study. More details in the scavenging characteristics are observed by a dye experiment, in which the dye path indicates the flow streamline in the cylinder. In the numerical study, three-dimensional flows are calculated by a modified version of KIVA-2 code, with a special technique to consider the valve and shroud shapes. The results show that a large shroud angle generates a center vortex in the cylinder by a strong reverse tumble flow, while a small shroud angle induces short-circuiting by a direct flow toward the exhaust valves. The shroud angle between 90 degree and 120 degree was found to be the optimal range for effective scavenging.
The Characteristics of Scavenging Flow in a Poppet-Valve Type 2-Stroke Diesel Engine by Using RSSV System
Sae Technical Papers
International Congress & Exposition ; 1996
1996-02-01
Conference paper
English
Automotive engineering | 1996
|Scavenging flow simulation of a four-poppet-valved two-stroke engine
Automotive engineering | 1993
|Scavenging Flow Simulation of a Four-Poppet-Valved Two-Stroke Engine
SAE Technical Papers | 1993
|Computational fluid dynamic simulation of a poppet-valve type, two stroke diesel engine
Automotive engineering | 1996
|Computational Fluid Dynamic Simulation of a Poppet-Valve Type, Two-Stroke Diesel Engine
British Library Conference Proceedings | 1996
|