共轨喷油器紧帽轴力测试及密封影响研究

Study on Test of Axial Force and Sealing Effect in Cap Nut of Common Rail Injector

共轨喷油器是柴油机燃油喷射系统的关键组成部分,越来越严格的排放法规使得柴油机的燃油压力越来越高,也对喷油器的密封性能提出了更高的要求。紧帽轴力是保证喷油器密封性的重要指标,基于某型共轨喷油器对紧帽轴力的测试方法、优化途径及密封影响进行了研究。结果表明:同等拧紧扭矩下,对紧帽进行涂覆和提高支撑面硬度均能有效地提高紧帽轴力、改善密封性能,其中表面涂覆对轴力提升的效果更显著;同时,这2种措施还能有效地减小轴力偏差,提升装配轴力一致性。

Common rail injector is the key component of the diesel fuel system. The fuel pressure becomes more and more high because of the increasingly strict emission regulation,so the injector seal ability put forward higher request. The axial force of cap nut is an important index to ensure the seal ability of injector,this paper studies the test method,optimization approach and sealing effect of axial force in cap nut based on a common rail injector. The results show that coating the surface of cap nut and increasing the hardness of the support surface can effectively enhance the axial force and improve seal ability under the same torque,in which the effect of surface coating on the improvement of axial force is more significant;meanwhile,these two measures can also effectively reduce the deviation of axial force and improve the consistency of assembly axial force.