Study On The Response Characteristics Of Pneumatic Supercharging Control System Based On PWM Control

The supercharging control technique is adopted by numerous diesel engines and developing faster and faster because of its obvious advantage in saving energy, increasing power and protecting environment. But there are few studies on the response characteristics of supercharging control system at home and abroad, which leads to unstable intake pressure in many high power diesel engines. To solve this problem,parts in the supercharging control system including exhaust bypass valve and the response characteristics of the supercharging control were studied.This paper is based on a prototype of the supercharging control system of certain high power diesel engine. Firstly, a test bench for the supercharging control simulation system was set up and applied to test the internal pressure in exhaust valve actuators and the change law of displacement in valve stem at different air source pressure.Secondly, a one-dimensional mechanical hydraulic performance simulation software AMESim was applied to set up the simulation model of supercharging control simulation system, calibrate and check the system, eventually influence factors and change law of scaling process of the bleed valve stem was explored. By changing related parameters of air source pressure, PWM control, electromagnetic valve seat diameters, the spring stiffness and initial pretightening force of exhaust valve actuators, how these parameters affect the change laws of both internal pressure in exhaust valve actuators and displacement in valve stem were studied.Thirdly, by simulation and analysis, the response characteristics curve of exhaust bypass valve controlling supply pressure of constant flow air source was studied. By changing parameters of PWM control, electromagnetic valve seat diameters, the spring stiffness and initial pretightening force of exhaust valve actuators, the influence law how exhaust valve actuators affects the stability of air source pressure was studied.The influence factors and the change law of the bleed valve stem scaling process and the influence law how exhaust valve actuators affects the stability of air source pressure were obtained through the work done above, which provides a theoretical basis for the stability of intake pressure in the actual diesel engines.