Design of a stand-alone control strategy for retrofit hybrid electric vehicles

The high cost of fossil fuel and environmental concerns forced the automotive industry to seek innovative ways to improve gas mileage. The short term solution to these concerns is the concept of hybrid electric vehicle (HEV) that combines the use of an internal combustion engine (ICE) and an electric motor (EM).;The energy of the battery used by a HEV can come from renewable sources such as solar and wind energy. It can also come from the energy recovered while decelerating the vehicle. The use of hybrid vehicles creates new control challenges in the area of energy management. Previous research on hybrid vehicle control focused on the torque/power split between the internal combustion engine and the electrical motor to operate them at the most efficient torque-speed characteristics. These control strategies are difficult to implement. They require a built-in controller, torque/power splitter and other transmission integrated devices which make the system very complex and expensive. In addition such design can not be easily adapted to existing single engine vehicles.;This research deals with the design of a novel control strategy using an add-on package for retrofit HEVs. To accurately predict the required torque for a wide range of vehicle, a fuzzy model that includes the variation of the parameters of the vehicle dynamical model has been developed. Simulation results were carried out for various vehicles with and without the add-on package. Preliminary simulation results show an improvement of 34% to 165% in gas mileage.