发动机气缸垫外漏冷却液的机理与试验验证  

Principle and Experimental Verification of Coolant Leakage of Engine Cylinder Gasket

作　　者：于士博 李云虹 熊润祥 张笛 郭旭阳 陈毅 Yu Shibo;Li Yunhong;Xiong Runxiang;Zhang Di;Guo Xuyang;Chen Yi(GAC Automotive Research&Development Center,Guangzhou 511434,China)

机构地区：[1]广州汽车集团股份有限公司汽车工程研究院,广州511434

出　　处：《机电工程技术》2024年第3期111-115,共5页Mechanical & Electrical Engineering Technology

摘　　要：某发动机在台架冷热冲击试验中多次发生气缸垫外漏冷却液问题,在同步进行的道路试验中也出现同样问题。为查明原因并加以改善,使用有限元方法搭建了发动机整机网格模型,分别将仿真和试验的温度场和冷却液压力流量等作为边界条件,进行了气缸垫密封性能的动态仿真。为验证仿真结果的准确性,使用微型高精度位移传感器进行了预定位置的缸体缸盖间隙测试。结果表明:(1)在瞬态工况过程中,发动机缸体缸盖的间隙大部分时间低于常温停机状态,但在发动机快速进入大负荷而冷却液温度仍在上升时,间隙逐渐拉大并高于常温状态,此工况下发生发动机冷却液渗漏;(2)通过有限元方法建模和仿真计算气缸垫密封线压力,并使用实测温度和气缸垫特性作为边界,计算结果准确,可以有效评定气缸垫的密封性能;(3)首次采用安装小型位移传感器的方法准确测量了发动机动态工况中缸体缸盖的间隙,可以与仿真结合使用,能够准确找到发动机气缸垫外渗漏冷却液的工况和位置,明确了气缸垫外渗漏冷却液的解决方向。(4)发动机气缸垫功能层结构和层数直接影响密封性能,尤其是缸体缸盖间隙变大工况的密封性能。The coolant leakage of cylinder gasket of an engine occurred many times in the bench thermal shock test and in the simultaneous road test.In order to find out the reasons and make improvement,the dynamic simulation and test of the sealing performance of the cylinder gasket are carried out.In order to verify the accuracy of the simulation results,a small high-precision displacement sensor was used to test the clearance of the cylinder block and head at a predetermined position.The results show that:(1)the distance between the engine block and the cylinder head is lower than the normal temperature engine shutdown state in most of the transient working conditions.When the engine rapidly enters high load while the coolant temperature is still rising,the distance between the cylinder block and the cylinder head gradually increases to the normal temperature engine shutdown state,and the engine coolant leakage occurs in this working condition.(2)The sealing line pressure simulation of the cylinder gasket is modeled and calculated by the finite element analysis method,and the temperature and characteristics of the cylinder gasket tested by the entity are used as the boundary conditions for calculation.The results are accurate and can effectively evaluate the sealing performance of the cylinder gasket.(3)For the first time,the method of installing a small displacement sensor is used to accurately measure the distance between the cylinder block and the cylinder head in the dynamic working condition of the engine.This method can be used in combination with simulation to accurately find the working condition and position of the engine cylinder gasket leakage of coolant,so that the direction of solving the problem of cylinder gasket leakage of coolant is clearer.(4)The structure and number of functional layers of the engine cylinder pad directly affect the sealing performance,especially the sealing performance when the distance between the cylinder block and the cylinder head increases.

关 键 词：发动机 冷热冲击试验 气缸垫 外漏冷却液 线压力 台架试验 

分 类 号：U464[机械工程—车辆工程]