Analysis of fretting wear behavior of unloading valve of gasoline direct injection high pressure pump
Liang Lu, Yin-peng Xu, Mengru Li, Qi-long Xue, Man-yi Zhang, Liangliang Liu, Zhong-yu Wu
Abstract
The high pressures in gasoline direct injection technology lead to structural damage in some hydraulic components, especially annular damage on the contact area of the valve ball and on the valve seat of the spherical unloading valve in the high-pressure pump. In previous study, the authors have analyzed the damage on the unloading valve and demonstrated that it is caused neither by static damage nor fatigue damage and have put forward the hypothesis of fretting wear. This paper is based on the establishment of the statically indeterminate structure of the unloading valve. The micro friction parameters (stress, friction coefficient, etc.) required for the numerical iterative calculation of fretting wear are calculated. In addition, based on the grid adaptive technology and a modified Archard wear model, the fretting wear is calculated quantitatively and is in good agreement with experimental results. Based on that verification, the wear laws of the valve ball and valve seat under the same hardness, different contact angles, and different assembly stresses, are analyzed in detail, and reasoned suggestions for the structural design and assembly design of the ball valve are given.