摘要
某四缸汽油增压发动机在搭载某款SUV整车耐久试验过程中,排气歧管隔热罩出现开裂现象,通过分析此隔热罩的共振特性、应用环境、疲劳因素,结果表明隔热罩开裂不是由共振原因,而是由于起筋处疲劳应力超过了其材料的屈服极限,在整车耐久变工况的冷热冲击下受排气歧管热膨胀量变化,产生撕裂。通过对比标杆机隔热罩筋结构,采用消减起筋位置应力,根据整车试验标准计算失效时间及CAE中的疲劳因子分析进行校正方案设计,整改后通过整车耐久试验。
Heat insulation cover of a certain turbo-charged gasoline engine cracked while the engine was mounted on sport utility vehicle during the endurance test. Modal analysis of the heat insulation cover shows that resonance is not the cause of the crack. The deformation of the temperature cycle leads to the stress of ribs which exceeds the yield strength of material. After the modification of the ribs structure according to the benchmark engine, the stress of ribs decrease. The new design guarantees that the fatigue safety factor can satisfy the vehicle endurance test demand. No fatigue occurs during the vehicle endurance test any more.
出处
《内燃机》
2016年第2期59-62,共4页
Internal Combustion Engines
关键词
增压汽油机
隔热罩开裂
疲劳因子
疲劳应力
turbo-charged gasoline engine
heat insulation cover crack
fatigue safety factor
stress
