某汽油机排气歧管热机疲劳分析

Thermal Mechanical Fatigue Analysis of Exhaust Manifold of a Gasoline Engine

建立了由额定转速全负荷、额定转速倒拖、怠速三个典型工况组成的排气歧管热载荷循环,采用有限元方法来获得各工况下排气歧管的瞬态温度场分布,并进行了非线性应力应变计算。最后,以排气歧管材料在热载荷循环中产生的等效塑性应变作为评价准则,对该排气歧管的热机疲劳性能进行了预测和评价。分析结果表明:该排气歧管设计满足使用要求。

The paper typical working conditions establishes the thermal cycle loading of the exhaust manifold under three including full load at rated speed, motered operation at rated speed, and at idle speed. Using Finite Element Analysis, it obtains the transient temperature field distribution of the exhaust manifold under all working conditions and does nonlinear strain calculation, and finally evaluates the thermal mechanical fatigue performance of this exhaust manifold according to equiva- lent plastic strain that this exhaust manifold materials produces during the thermal cycle loading. The result shows that the design of the exhaust manifold meets applicable requirements.