| To meet the increasingly strict emission regulations and the always existent request for reducing the consumption of fuel, and to improve fuel spray cone angle and tip penetration, high pressure fuel injection system has already become a feasible key technology for inline injector, which also brings the problem of the seizure and scuffing of the plunger and the fuel leakage between plunger and its barrel. The clearance between plunger and its barrel deeply affected cycle fuel supply and injection pressure, so the lubrication and sealing of fine couplings should been taken into consideration.This paper presented the factors that influenced the fuel pressure distribution, and the fuel flow in clearance between plunger and its barrel. Depending on the fluid theory of laminar flow in slit flow way and with consideration of fluid leakage and viscous friction energy consumption, the formula of optimal radial clearance was established The paper analysed the structural deformation of the couplings and their stress concentration basing on its structure and its bearing and finite element analysis method. Finally, a system model was set up using HYDSIM software, and the simulation result of the leakage and the ways to reduce the leakage problem were acquired.The analysis study of this paper is based on upgrade of EP9 series injector to P7100 series. The results can be applied to provide theory basis for injector improvement in the course of its development. |
