汽油机液压张紧器对正时链系统噪声影响的研究

Study on Influence of Hydraulic Tensioner of Gasoline Engine on Noise of Timing Chain System

整车试验过程中某增压直喷四缸汽油发动机在一档爬坡过程中产生“哒哒”异响,异响工况发动机转速1200rpm~1300rpm,机油温度升高后异响更加明显,平地起步和转速升高或降低后异响消失,经过初步诊断为正时系统液压张紧器产生异响,此异响与正时系统驱动零件(如凸轮轴、高压油泵)和液压张紧器自身性能有关。通过对正时系统测试进一步分析,发现液压张紧器与整机不匹配导致异响,通过对液压张紧器进行优化,经过NVH试验和500h交变负荷试验,验证效果良好。

During the whole vehicle test,a booster direct injection four-cylinder gasoline engine produces"da da"abnormal sound during the first climbing process.The engine speed is 1200rpm~1300rpm under the abnormal sound condition,and the abnormal sound becomes more obvious after the temperature of the engine oil rises,the abnormal sound disappears after the start of the flat ground and the rise or fall of the rotating speed.After preliminary diagnosis,the abnormal sound is generated by the hydraulic tensioner of the timing system,which is the same as the driving parts of the timing system(such as camshaft and high-pressure oil pump).It is related to the performance of the hydraulic tensioner itself.Through the further analysis of the timing system test,it is found that the mismatch between the hydraulic tensioner and the whole machine leads to abnormal sound.Through the optimization of the hydraulic tensioner,NVH test and 500H alternating load test,the verification effect is good.