针对某柴油机气门导管在整机台架试验过程中发生的横断和纵裂失效故障，对气门导管的材料性能、结构应力、微动磨损、热变形、装配工艺等影响因素进行了分析。分析结果表明：材料力学性能差和装配过盈量较大造成的应力集中和微动磨损是气门导管横断的主要原因；液氮人工压装的装配工艺是造成气门导管纵裂的主要原因。据此提出新方案气门导管，并通过了整机台架试验验证。

For the transversal and longitudinal fracture failure of diesel engine valve guide during engine bench test, the influencing factors such as material performance,  tructural stress, fretting wear, thermal deformation and assembly process were analyzed. The results show that the poor mechanical properties and the stress concentration and fretting wear caused by large assembly interference are the main reasons leading to valve transection. The assembly process of liquid nitrogen artificial pressing is the main cause of longitudinal crack for the valve guide . Accordingly, a new scheme valve guide is proposed and verified by bench test.