Scavenge flow analysis of opposed-piston two-stroke engine based on dynamic characteristics

• Published in: Advances in mechanical engineering 2015-04, Vol.7 (4)
• Main Authors: Ma, Fu-kang, Zhao, Chang-lu, Zhao, Zhen-feng, Zhang, Shuan-lu
• Format: Article
• Language: English
• ISSN: 1687-8132; 1687-8140
• DOI: 10.1177/1687814015581569

Opposed-piston two-stroke engine has been proposed by Beijing Institute of Technology to improve power density and complete machine balance relative to conventional engines. In order to study opposed-piston two-stroke engine scavenging flow, a scavenging system was configured using a three-dimensional computational fluid dynamics model effectively coupled to experiments. The boundary conditions are obtained through one-dimensional working process simulation results and experiments. As the opposed-piston relative dynamic characteristics of opposed-piston two-stroke engine depend on different design and operating parameters including the opposed-piston motion phase difference and crank-connecting rod ratio, a numerical simulation program was built using MATLAB/Simulink to define opposed-piston motion profiles based on equivalent crank angle of opposed crank-connecting rod mechanism. The opposed-piston motion phase difference only affects scavenging timing while crank-connecting rod ratio affects scavenging timing and duration. Scavenging timing and duration are the main factors which affect scavenging performance. The results indicate that a match of opposed-piston motion phase difference and crank-connecting rod ratio has the potential to achieve high scavenging and trapping efficiency with a right flow in cylinder.