摘要
为改善连杆小头轴承润滑及活塞销冲击特性，基于粗糙峰接触理论、平均流量模型及弹流润滑理论，以某高压共轨4缸柴油机为研究对象，运用AVL EXCITE Power Unit软件搭建混合润滑活塞连杆组多体动力学模型，研究了考虑空穴条件下不同转速对连杆小头摩擦副润滑及冲击特性的影响规律。研究结果表明：标定功率转速2 400 r/min下，在做功时刻1 080°后峰值油膜压力达到最大值197.1 MPa，最小油膜厚度达到最小值1.8 μm，而润滑油填充率在整个发动机循环过程中均低于0.12。在怠速800 r/min、最大扭矩转速1 600 r/min、标定功率转速2 400 r/min下，进气、压缩、做功、排气4个冲程过程中，空穴区域由连杆小头轴承下半区转移至上半区、再转移至下半区。转速升高会导致峰值油膜压力增大，最小油膜厚度减小，粗糙接触压力增大，活塞销Z向速度峰值加大，对连杆小头轴承冲击加重，在缸内最高燃烧压力时刻，800 r/min，1 600 r/min，2 400 r/min下的平均润滑油填充率均值为0.84，0.70，0.69，因润滑油填充率随转速的升高而降低，空穴程度加重。
Abstract
In order to improve the lubrication and piston pin impact characteristics of connecting rod small-end bearing, a multi-body dynamic model of mixed lubrication piston and connecting rod group was built by AVL EXCITE Power Unit software with a high-pressure common rail four-cylinder diesel engine as the research object based on the rough peak contact theory, average flow model and elastohydrodynamic lubrication theory. The influence of cavitation effect on the lubrication and impact characteristics of connecting rod small end frictional pair at different speeds was studied. The results show that the peak oil film pressure reaches the maximum value of 197.1 MPa and the minimum oil film thickness reaches the minimum value of 1.8 μm after 1 080° at the rated power speed of 2 400 r/min, while the lubricating oil filling rate is lower than 0.12 during the whole engine cycle. Under the idle speed of 800 r/min, the maximum torque speed of 1 600 r/min, and the rated power speed of 2 400 r/min, the cavitation area first transfers from the lower half of the connecting rod small-end bearing to the upper half, and then back to the lower half during the four strokes of intake, compression, work, and exhaust. The increase of the speed will lead to the increase of peak oil film pressure, the decrease of minimum oil film thickness, the increase of rough contact pressure, the increase of Z-direction velocity peak for piston pin, and the increase of impact on the small-end bearing of connecting rod. The average filling rates of lubricating oil at 800 r/min, 1 600 r/min and 2 400 r/min are 0.84, 0.70 and 0.69 respectively, and the aggravation of cavitation becomes true because the filling rate of lubricating oil decreases with the increase of speed.
关键词
空穴效应 /
连杆小头 /
润滑特性 /
冲击特性
Key words
/
mso-bidi-font-family: 宋体">cavitation effect;connecting rod small end;lubrication characteristic;impact characteristic
毕玉华，杨钊乾，马雄，刘少华，唐明超.
考虑空穴效应的连杆小头摩擦副润滑特性与冲击影响研究[J]. 车用发动机. 2024, 0(2): 9 https://doi.org/10.3969/j.issn.1001-2222.2024.02.002
BI Yuhua，YANG Zhaoqian，MA Xiong，LIU Shaohua，TANG Mingchao.
Lubrication Characteristics and Impact Effects of Connecting Rod Small-End Frictional Pair under Cavitation Effect[J]. Vehicle Engine. 2024, 0(2): 9 https://doi.org/10.3969/j.issn.1001-2222.2024.02.002
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
