Technical Paper
Design of an Optimal Control Strategy in a Parallel Hybrid Vehicle in Order to Simultaneously Reduce Fuel Consumption and Emissions
2011-04-12
2011-01-0894
In this paper, an optimal control strategy is developed. The control strategy aims to simultaneously reduce fuel consumption and emissions of a parallel hybrid electric vehicle (HEV). A continuously variable transmission (CVT) is implemented in the HEV model. The CVT has a significant role to operate the internal combustion engine (ICE) near its optimal operating points; consequently its proper control will contribute to enhance the fuel economy and emissions. Using a trade-off between the fuel consumption and emission rates, improving the fuel consumption can cause the emission rates to be improved too. First, 5 different modes for the vehicle motion is defined. Afterwards, depending on the state of charge of the battery (SOC) and the requested power from the driver, the best mode, in each time step, is chosen. Knowing the best mode, the control strategy refers to ICE or electric motor (EM) pre-calculated optimal curves, and determines ICE/EM output speed (i.e. input speed to CVT).
