عنوان مقاله [English]
In this paper, the objective is to optimize the control parameters of a parallel hybrid electric vehicle equipped with continuously variable transmissions (CVT) in SC03 driving cycle. At first, the impacts of using CVT instead of manual transmission on the fuel consumption (FC) of the vehicle are investigated, quantitatively. It is shown that by using CVT, the rotational speed of the engine is not limited by vehicle speed. Hence, the engine rpm can be determined to achieve minimum FC. Then, an algorithm is introduced to calculate the FC of the vehicle equipped with CVT, and the speed ratio of CVT is specified to minimize the vehicle FC. The model accuracy is investigated by comparing its results with manufacturer documents. An algorithm which is on the basis of a baseline static control strategy (BSC), is introduced to control the parallel hybrid electric vehicles. In this algorithm, the engine is the primary power generator, and the electric motor in conjunction with the battery, acts as an auxiliary power supply. By utilization of the introduced control algorithm, the FC of a vehicle equipped with a five-speed manual transmission is about 30% lower, compared to non-hybrid version of the vehicle. Finally, a multi-objective ptimization is accomplished to minimize both FC and the battery capacity. To multi-objective optimize the control algorithm, a method similar to PSI was exploited. In this method, at each step, an upper bound for the battery capacity is defined as a constraint, and FC as the objective function is minimized. By gradually increasing the upper bound of the battery capacity and running the algorithm, the battery capacity of the optimized system and the vehicle FC, versus the upper bound of the battery capacity, is obtained. It is found that by using the optimized control algorithm, the FC of the vehicle equipped with CVT in the SC03 driving cycle is 35% lower, compared to the application of a five-speed manual transmission, and no optimized control algorithm.