热应力产生的根源在于“热胀冷缩受到约束” ,降低温度幅值和解除或减弱热变形约束是减小热应力的两个最基本的方法。作者重点对解除热变形约束减小热应力的各种常用措施进行了分析、探讨 ,并针对解决 4 10 2QBZ发动机的热负荷与缸盖冷却问题进行了具体分析 The root cause of thermal stress is that “thermal expansion and contraction are restrained.” Reducing the temperature amplitude and relieving or reducing the thermal deformation constraint are the two most basic methods to reduce the thermal stress. The author focuses on the analysis and discussion of various commonly used measures to relieve the thermal deformation restraint and reduce the thermal stress and carries out a specific analysis to solve the 4 10 2QBZ engine thermal load and cylinder head cooling problems