红外无损检测技术在发动机缸盖热状态监测中的应用

Infrared Non-destruction Testing Technology Applied to Monitoring Thermal Situation of Engine Cylinder Head

缸盖热状态的正常与否是保证发动机可靠工作的重要因素之一。本文以某型柴油机缸盖为研究对象,确定了高、中、低3种试验工况,采用红外测温技术,检测了实机工作状态下缸盖外表层测点温度随发动机工况的变化规律。提出相对灵敏度的概念,并结合数值仿真,确定了发动机缸盖表层温度特征区域。试验和仿真结果表明,在缸盖结构以及发动机工况一定时,缸盖的所有传热边界条件也保持一定,缸盖表层温度可综合反映其整体温度场,可作为评价其热状态的依据。该研究为实现发动机缸盖热状态的在线监测提供了新的途径,同时也拓展了红外检测技术的应用领域。

Whether thermal situation of cylinder head is normal or abnormal is one of important factors for the evaluation of engine＇s reliability performance.Aiming at a certain engine cylinder head,three testing working conditions were made,which included maximum out power,medium out power,and minimum out power.By infrared temperature detecting technology,the rule of outer surface temperature field of cylinder head changing with engine working conditions was studied.A new concept of relative sensitivity,which is defined as degree of measuring point temperature changing with working conditions,was put forward.Combined with simulation calculation results,characteristic temperature field distribution areas were made certain on outer surface of cylinder head.The results show that temperature simulation values are well matched with temperature experimental values.Under same cylinder head structure and engine working condition,the heat transfer condition is same too.And the thermal situation performance of cylinder head can be described by its outer surface temperature values,which provides a new gist for monitoring thermal situation of cylinder head on-line.Furthermore,applying infrared temperature measurement to engine will have a widely foreground.