Study On The Multi-point Gas Injection System Based On Pressure Control

In multi-point gas injection system based on time control the gas pressure when injection valves work is almost the same.The control system controls injection quantity by controlling injection duration.The injection duration is different under different loads.Gas and air are mixing into the cylinder though intake valve during injection duration,but only air enters the cylinder in the other time of intake duration.Air and gas are mixed unevenly by this intake method.In order to improve the situation,this paper presents the multi-point gas injection system based on pressure control.Injection quantity is controlled by injection pressure in the pressure-control gas injection system.The research has insights on the development of the pressure-control gas injection system and has finished these works:The research analyzed the disadvantages of the time-control gas injection system based on indicator diagram of a 12v190 gas engine.Through building simulation for the 12v190 gas engine,analyzing and comparing the quality of mixture gas near the intake valve in two injection systems,we got the advantages of the pressure-control gas injection system.The research designed and established the simulation test platform for the pressure-control gas injection system and selected the appropriate sensors and gas control valve.The research developed hardware circuit with the main chip of MC9S12XEP100,completed the acquisition of rail pressure signal and gas temperature signal and developed the drive module for solenoid valves.The research developed the bottom code of the drive module for the simulation test platform of the pressure-control gas injection system,completed the acquisition of analog signal and the drive control of injectors and gas control valve and developed the upper computer software for this multi-point fuel injection system based on pressure control.With the data acquisition card,the acquisition monitor system has been developed for of the test platform.The simulation test has been carried out on the test platform studying on influencing factors for gas pressure build-up,gas pressure fluctuation and gas pressure responsiveness.The research discussed the feasibility and adaptability of the pressure-control gas injection system through the results.The research constructed a simulation model based on MATLAB/Simulink for the pressure-control gas injection system.Discussed and analyzed how to choose working pressure and gas source pressure of the pressure-control gas injection system and the responsiveness and control accuracy of gas control valve.