The Siulation Optimization And Performance Improvement Of Gas Engine

This thesis mainly did some research on the simulation of gas engineand the method of the engine performance improvement.At first, analyze the national advanced gas engine, then refer to thisdata, made a preliminary viable analysis about the improvement of12V190 gas engine, estimated the needed BMEP and thermal efficiency.The 12V190 gas engine made by shengli use the ordinary spark plug,so knocking and high thermal load should be the most important problemwhen engine's power is improved. So the pre-combustion chamber sparkplug can improve the lean burn limit and the engine'output. Theexperiment proved the pre-combustion chamber spark plug couldaccelerate the flame propagation velocity. The new type engine use thepre-combustion chamber spark plug, in order to update this new engine,build GT-Power model to calculate the engine's thermodynamic powercycle. After analyzing the result, changing the turbo-charge is regards asthe method. Then use the GT model forecasted the engine performancewith new turbo.The experiment result didn't match the calculation, after analyzing thedifferences between the model and the test condition, ambient temperatureis regards as the reason and the model was correct. As the forecast result,the engine's output increased by new turbo. Use the Mode Frontier tooptimize the MPC design parameters and the cam design parameters.Knocking is the biggest challenge after the engine outputimprovement. In order to enhance the BMEP to 18 MPa Miller cycle mustbe used on the engine based pre-combustion chamber spark plug. The Miller cycle can decrease the effective compression ratio means it candecrease the knocking tendency. But Miller cycle have a negative impacton volumetric efficiency. So, only a high-pressure ratio turbo-charge beused can engine power improve. Build a PID control module and adjust theturbo circulation section to make the BMEP fixed. Build a single cylinderMiller cycle model, and the result show that knocking tendency is decreaseby Miller cycle. Then used Miller cycle on 12 cylinders model anddetermined a suitable scheme.After the researches above, 12V190 gas engine's performance hasbeen improved greatly.