چكيده به لاتين
In this study, the turbocharged spark ignition engine is simulated in the GT-Power software and the focus is on the transient torque response. The base engine is the EF7-TC which is a spark ignition 1.65 L engine equipping with the turbocharger. Calibration of the engine model in the GT-Power software during the transient and its differences with the steady-state calibration are investigated. In this calibration, the processes of injection, combustion, heat transfer in the exhaust manifold and the turbocharger performance are calibrated and validated for the transient. In this step, a proper method is presented to predict the turbocharger’s transient behavior, especially in low rpms where no experimental data are available. To validate the obtained results from the simulated engine model in the GT-Power software, the received experimental data from the Iran Khodro Powertrain Company (IPCO) are used. In this research, the optimization during the transient is performed dynamically and the coupling of GT-Power, MATLAB m-file and SIMULINK is used for optimization to find appropriate setting for simultaneous application of the turbocharger waste gate and the variable valve timing during the transient. The optimization aim is to maximize the torque integral in the time interval of the transient. The transient studied in this research is the one in which the engine rpm is constant and the engine load increases from an initial value to a secondary value by opening the throttle. Genetic algorithm is used for optimization. The results show that by using this optimization, the improvement percentage of the torque integral in rpms of 1750, 2000 and 4500 are 7.92, 12.66 and 3.67 respectively. The other result of this study is that if the ratio of output/input pressure in this engine is about 1.1 during the transient second phase, the engine transient performance will be optimized.
