Numerical simulation analysis on the flow field characteristics of electric-controlled pressure amplifier for ultra high pressure common rail system

On the basis of introducing the working principle of the electric-controlled pressure amplifier for ultra high pressure common rail system, the three dimension flow field characteristics model of it was built by FIRE software, and the accuracy of this model was verified by the pressure curve in pressurization chamber which obtained via the ultra high pressure common rail system injection characteristic experiment, then the numerical simulation analysis on the three dimensional flow field characteristics of electric-controlled pressure amplifier was conducted based on the model, and the flow field pressure and velocity distribution law during the pressurization process were obtained. The results show that when the flow field of pressurization oil circuit is at the end of compression stroke, the highest pressure mainly distributed around the outlet of electric-controlled pressure amplifier, and the maximum velocity mainly distributed around the oil inlet passage of one-way valve chamber and pumping chamber. When the flow field of control oil circuit is at the end of compression stroke, the pressure in control volume reduced greatly, and the pressure of control volume outlet orifice was less than critical pressure during pressurization process, which may lead to the occurrence of gasification phenomenon. This research provides a basis for analysis design rationality and specify structural optimization direction of electric-controlled pressure amplifier, at the same time, combining with the choice of fuel injection pump and injector, it is helpful to speed up the design of ultra high pressure common rail system and optimize the combustion system matching of diesel engine.