A Study For Control Model And Dynamic Simulation On Spark Ignition Engine Fueled With Coal Bed Methane

The development and usage of Coal Bed Methane(CBM) gas is very important for best use of energy and optimizing our country's energy structure, and also very meaningful for decreasing damage in coal mine and protecting global environment .From LiuWu Program's beginning ,especially from 90's age, our country regard study in CBM as very urgent agenda, and at present this work has been contained in our country's ShiWu energy development plan.The main study in this dissertation are about establishment of control model , dynamic simulation and theory analysis of modified S195 with CBM in variable element and concentration. First introducing gas engine's study in present of domestic and overseas, then analysis the feasibility of CBM engine and also the introduction of CBM engine system. It contains establishing control model of this engine, the models are based on engine average value in time, they can be divided as intake manifold, engine dynamics, velometer section and other subsystem model of CBM engine. Besides these, it also contains model of sensors using in engine intake system and running detection, model of step motor using in driving throttle. The intention of establishing model is to realizing CBM engine's air fuel ratio control and speed control, at last to carry out dynamic simulation based on MATLAB/SIMULINK.In A/F ratio control, through the analysis of structure of step motor, its static and dynamic model was established with reasonable tolerance, with transfer function of the control system, modifying in control strategy and selection in control parameter, a effective control unit was designed, it can be used in control of A/F ratio of CBM engine.In speed control, in according to the criterion experiment of fuel pump and based on the platform of MATLAB, a program was compiled, in SIMULINK environment this program can be transferred as S-fanction. Through simulation result, it can be found that it has good coherence with practical value and can be suitable in engine speed control.In unitary simulation, regarding output speed and effctive torque as two main conference value to have SIMULINK simulation and have a contrast with the actual output in engine test, the predict result has coherence with practical value in reasonable tolerance and can meet the requiry of the control goal.