Optimization Research Of A High-power Gas Engine

Numerous advantages of natual gas and the depletion of oil resourcemake the application of natual gas more widely, the market share of gasengine has also gradually increased. Energy crisis and increasinglystringent emissions regulations promote natural gas engine to obtain higherBMEP, higher thermal efficiency, lower emission.The research object of this paper are190series of high-power gasengines in a factory. Research purpose is to enhance the power and thermalefficiency of gas engines and reduce exhaust temperature, improve theuniformity of each cylinder and emission performance. Research method issimulation.The simulated models of16V190and20V190working process werebuilt with GT-Power software. The precision of16V190model wasvalidated through comparing the experimental data and simulation data.Optimization analysis about MPC exhaust system of two models showedthat using a large diameter exhaust pipe can significantly improve theuniformity of each cylinder, but do little effect on economic and powerperformance. For16V190, three schemes of double-entry turbine wereanalyzed by comparison. The results of the analysis showed that usingdouble-entry turbine exhaust system can reduce exhaust temperaturebefore turbine, improve volumetric efficiency of each cylinder and reduceresidual gas rate of each cylinder.Miller cycle research about two models were done through increasingthe geometric compression ratio and closing intake valve early or late.Thermal efficiency and power were improved, effective compression ratioand Nox emission were reduced. To make up for the decreased volumetric efficiency due to intake valve be closed early or late, a higher pressureratio supercharger should be equipped to ensure the intake air. The effectsof different valve overlap angle on the overall performance, including therequired inlet pressure, power, exhaust temperature before turbine and Noxemission, were calculated through establishing multi-point injectionsimulation models.The effects of lean burn on economic and power performance andexhaust temperature before turbine were analyzed based on single Webersimulation models. After that a dual-zone combustion mode wasestablished and the precision of the model was validated throughcomparing the experimental data and simulation data. Then thedeterioration of combustion was analyzed, research about increasingturbulence degree and ignition advance angle to improve the gas engineperformance was done.