气门机构液压间隙调节器内机油混气量的估算

Oil aeration in the high pressure chamber of hydraulic lash adjusters in engine valve trains

为对有液压间隙调节器 (HL A)的气门机构进行准确的动力学分析 ,应考虑 HL A高压腔内混气的影响。根据在气门机构试验中测得的气门加速度和 HL A高度变化量 ,以及从 HL A泄沉试验中得出的 HL A泄沉速度与受力之间的关系 ,可以推算出 HL A高压腔内混有空气的机油的体积弹性模量 ,进而算出空气的体积分数。采用这种方法对一气门机构的直动式 HL A内的混气情况进行了计算 ,将算得的高压腔机油混气量用于气门机构动力学计算 ,计算结果与实测气门机构动态特性基本一致 。

The oil bulk modulus reduction caused by aeration in the high pressure chamber of hydraulic lash adjusters (HLA) should be taken into account to accurately model and simulate a valve train with HLA. The bulk modulus of the oil/air mixture, and hence the volumetric air fraction, in the HLA chamber can be determined by measuring the HLA collapse and valve acceleration on an operating valve train, and HLA leakdown rate versus load on an HLA leakdown test rig. The method was used to determine the air content in direct acting HLA in car engines which was then used in a valve train dynamic simulation. The simulation agreed well with valve train measurements showing that the aeration can be accurately determined and that it may be used in valve train test analysis and aeration data accumulation.