转速变化对配气机构相关参数的影响

Design method on symmetrical MFB-Ⅱ cam profile of vehicular engines

针对传统运动学计算不足以准确描述配气机构各零部件的运动规律的问题,阐述了对用复合形法优化了的FB-Ⅱ凸轮,利用单自由度模型对FB-Ⅱ型对称凸轮的下置凸轮轴式配气机构进行动力学计算.计算结果表明,在工作状态下,配气机构各个零部件会发生较大变形;当凸轮轴转速变化时,配气机构各相关参数会发生相应的变化.FB-Ⅱ凸轮配气机构具有较大的丰满系数.FB-Ⅱ型线凸轮对转速低于3000r/min的柴油机是一种比较理想的选择.

This paper presents a symmetric valve driven FB-Ⅱ cam design and calculate procedure. Dynamic calculating method used to check its all kinds of properties including elastic change, during its different working conditions. We carefully select and optimize the performance and character parameters for the FB-Ⅱ cam. Properties of this air exchange gear can change greatly as the engine speed changes. According to the calculated results, with higher ample factor, FB-Ⅱ cam is an ideal selection for engine with a speed not high than 3000 r/m.