曲轴箱通风系统机油消耗试验与改进设计

对某型车用直列4缸柴油机开展了机油消耗、窜气和曲轴箱压力试验研究,试验结果表明该发动机在低负荷低转速工况下燃油消耗与机油消耗的比值(机燃比)不满足设计要求,随着转速和负荷的提高,总机油消耗量呈增加趋势,曲轴箱通风(PCV)系统所占总机油消耗比例较高,各工况点平均值约为10%。借助CFD仿真手段对原油气分离器及改进方案进行了对比分析,得知原结构油气分离效率较低,改进方案分离效率大幅提高。验证试验表明,3种对比工况下改进方案窜气特性和曲轴箱压力均满足设计要求,PCV系统机油消耗均大幅度下降,说明改进方案合理可行。

Lube Oil Consumption Test and Modified Design for Crankcase Ventilation System

The experiments of lubricating oil consumption ,blow‐by flow and crankcase pressure were conducted on a inline 4‐cylinder diesel engine .The test results show that the ratio between fuel consumption and lube oil consumption cannot satisfy the design requirements .The total lube oil consumption increases with the increase of speed and load ,the lube oil consumption of crankcase ventilation system takes a higher percent of total consumption and is 10% on average in each point .The original oil gas separator and modified design were compared and analyzed based on CFD simulation method ,which shows that the modified design has a higher separation efficiency .The verified experiment proves that the blow‐by flow and crankcase pressure can sat‐isfy the design requirements under three conditions and the lube oil consumption of crankcase ventilation system decreases sig‐nificantly .Accordingly ,the modified scheme is feasible .