Cycle Simulation Of157MQ Gasoline Engine And Optimization Scheme Design For Cylinder Bore Enlargement

This paper makes the157MQ and166MQ engine as the research object. Theengine cycle simulation and performance optimization was maked on the basis ofrelevant test. One feasible optimization scheme was put forward for157MQ and thespark advance angle was calibrated. Three kinds of optimization scheme was proposedand contrasted for166MQ for different perspective. Specific tasks are as the follows:The GT-Power cycle simulation model was set up for the engine according to thephysical structure of157MQ and the related test data, including Empty filter airresistance test, combustion characteristic value test, air-fuel ratio test, bench test,airway steady flow experiment and spark advance angle calibration, etc. The errorbetween simulation value and test value of the circulatory intake air and the torque waskept within5%after correction, so it can be used to the subsequent power performanceresearch and optimization.The sensitivity of everyparameter in the intake and exhaust system and the valvetiming was analysedvia DOEon the basis of the established simulation model. Allparameters was optimized to a certain extent according to the degree of the sensitivity.Eventually five parameters including the exhaust pipe diameter, the exhaust valvetiming and the exhaust closing angle, the intake opening angle and exhaust pipe lengthwas optimized. The power performance was enhanced to7.3%. In addition, the sparkadvance angle that balance the power with the emission performance was determinedto11°CA through the test means.The166MQ was enlarged bore from157MQ on the basis of the establishedsimulation model. The problem after bore-enlargement was discussed, that thedisplacement was enlarged by33%while the torque in the high speed is far less than33%. In order to optimize the power performance of166MQ and tap enlargement’spotential, three kinds of optimization scheme was designed on the principal of notworsen low speed, focus on optimizating high speed, that is the intake and ehxuast portfully optimized scheme and the intake and ehxuast port non optimized scheme and theintake and ehxuast port limitary optimized scheme. The optimization approach andoptimization results of each scheme was elaborated. three kinds of optimizationscheme was contrasted, each scheme can enhance the power performance up to35.1%, 24.7%and34.1%respectively. The ideal optimization scheme, the deprecatedoptimization scheme and the actionable optimization scheme was found.