活塞环开口位置对窜气特性影响的研究

在不改变活塞环组结构参数的情况下,为寻求降低活塞环组窜气量的优化方法,建立某柴油机活塞环组窜气特性模型,计算在1800 r/min全负荷工况下的窜气量.结合正交设计,在窜气特性模型中对活塞环组开口位置进行优化布置,并分别从活塞环开口、环槽与工作表面三条窜气途径对优化结果进行对比分析.优化方案将原方案的窜气量降低了10.3%,进一步分析表明环岸压力导致的油环震颤是原方案窜气量较高的主要原因.环岸压力对三条窜气途径的气体流量均有较大影响.通过调整环组开口位置合理分配环岸压力能有效降低窜气量,通过调整油环状态对压力的影响间接影响活塞环组的窜气特性. 

Influence of Piston Ring End Gap Position on Blow-by

In order to reduce blow-by through piston ring-pack without changing geometry parameters of piston and rings, a blow-by flow model was established. The blow-by in 1 800 r/min full load conditions was calculated firstly in this study. Then the positions of end gap were optimized based on orthogonal design. The gas flow through end gap, groove, and running face was calculated and analyzed separately. Results show that the optimization scheme can reduce the blow-by by 10.3% compared to original scheme. And the reason that the higher blow-by produces in original scheme was analyzed. It is mainly due to the oil ring flutter caused by piston land pressure. Gas flow was greatly influenced by land pressure in all the three flow channels. Blow-by can be reduced effectively by reasonable adjustment of end gap and rational allocation of land pressure. The state of oil ring can influence the blow-by indirectly by changing the land pressure.