Dynamic optimization of load step transient response of a turbocharged spark ignition engine focusing on valves timing

Demand increase for reduction of fuel consumption and emissions of internal combustion engines has caused technology development in the automobile industry. A successful solution is downsizing the internal combustion engines and adding turbochargers to them. One of the consequences of adding turbocharger to the engine is slower transient response of the engine in comparison to the naturally aspirated engines. In this paper, the engine simulation is done in one-dimensional software GT-POWER and the torque transient response is being focused. For optimization, the coupling between two software of GT-POWER and MATLAB SIMULINK is used to find a rapid way for calculation of a proper strategy in order to utilize variable valve timing (VVT) technology during the transient. Variable valve timing in this study refers to opening and closing timing of inlet and exhaust valves. The optimization target is to maximize the torque integral during time interval of the transient. The transient in this paper is the one in which the engine speed is constant and the load increases rapidly and suddenly to a special value (step increase of load). Improved genetic algorithm is used for optimization. The studied engine is 1.65 liters EF7-TC which is a spark ignition engine equipped with turbocharger.