Optimization of Scavenging Port Structure of OP2S Engine Ventilation System
The opposed piston two-stroke engine is a kind of engine without valve mechanism and cylinder head.The air exchange process is an important factor affecting the combustion efficiency and emission level of the whole engine.The CFD simulation model of the ventilation part of OP2 S engine is established by using Fluent,and the air flow law in the cylinder of single layer scavenging port structure and compound scavenging port structure is studied when the scavenging inclination angle is 20°.The results show that in the single layer scavenging port structure,there is an obvious area with lower velocity at the bottom of the cylinder during air exchange,and the distribution area of residual exhaust gas around the cylinder shaft near the axis is larger.The scavenging air flow of the compound scavenging port structure flows through the center and outside of the cylinder axis,and the circumferential velocity component along the cylinder axis plane decreases when the fresh gas is filled into the cylinder,which is 6.2%higher than the turbulent kinetic energy of the single-layer scavenging port structure.The residual exhaust gas coefficient is effectively reduced,the ventilation effect is obviously better than the single-layer scavenging port structure,and the scavenging efficiency is improved.
opposed piston two-stroke enginescavenging processscavenging port structure
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