Research On The Transient Leakage Characteristics In Piston Pairs Of Common-rail High Pressure Fuel Pump Based On The Micro Motion

Piston pairs are one of the most sophisticated and the most important parts on the high pressure fuel pump assembly. With the improvement of the oil pressure, the sealing performance of piston pairs has significant effect on the pump capacity. Practice has proved that the micro motion has a specifically significant impact. Hence the main contents in this research are shown as follows:(1) The high pressure fuel pump works briefly were introduced and the paper established the precise physical model of the important piston pairs. Introducing the dynamic pressure theory, the equilibrium analysis was carried out. In order to get the acentric distance and the inclined angle of piston pair, the paper was coupled dynamic model to solve.(2) In the model, full account was taken of the piston eccentricity, elastic deformations of piston pairs, and the unified model for the physical properties of the fuel. The numerical method for the solution of the model was given, and the model was validated by comparing the calculated leakage rates with the measurements. Some of the conclusions provide good guidance for the design of high pressure fuel pumps.(3)Transient leakage model based on the micro motion of piston pairs was used to calculate the plunger pressure and the transient leakage value, which affected by structural parameters of the plunger and the cam, operating parameters and physical parameters of fuel. Finally, a small piston diameter is recommended, which provides guidance for the structural design of the high pressure fuel pump.