Research On The Leakage Test Method Of Suction Valve And Non-return Valve Based On High Pressure Common Rail Pump

With the development of automobile industry,the high pressure pump is applied widely.The low pressure fuel can be compressed till 2500bar in a high pressure fuel injection diesel pump and transported to the common rail for storage.Only if the pump's tightness is assured can the whole engine system operate perfectly.The work efficiency of pumps is significant for improving the performance of engine system.Nowadays,common rail pump is taken as one important part of developing diesel autos.Theoretically,the metallic contact area is considered of static contact under the gas pressure based on the influence that the metallic coarseness contact surface upon the tightness.The contact model of sealing surfaces was established on the basis of the modified M-B model,and the relationship between the contact area and the compressive stress is obtained.It's found that the compressive stress will increase with the increase of the contact area.Under the same load,the bigger fractal dimension and the less scale coefficient could lead to the bigger the contact areal.These studies can be used in the evaluation of sealing behavior of metallic surface.A leakage test system of the suction valve and the non-return valve of pumps was developed in this paper.By improving the test accuracy,this method was realized in series production line.Particles were weld by laser in order to simulate the authentic circumstance in this leakage test system.The pressure drop of pumps during leakage testing was measured by LMS for judging the tightness.Different parameters were optimized in order to improve the performance of the whole leakage test system.Furthermore,a new method of testing the tightness of the suction valve and the non-return valve was developed:pump tightness was determined by measuring the left pressure in compress room.This simple manipulated leakage test system was realized in assembly line successfully.It is proved that the no-start problems of engines were dramatically decreased with the implementation of this new test system.