Conceptual Design and Optimal Torque Sharing Strategy for Hybrid Vehicles with Epicyclic Gear Trains

The paper presents a novel approach in torque sharing between an internal combustion engine (IC engine) and two electrical motors for optimal drive of a hybrid vehicle. The concept of the system is realized by employing the three degrees of freedom (DOF) twin epicyclic gear train with specially selected gear ratios to satisfy an optimal power sharing strategy. The first stage of the train provides high torque from the IC engine and moderate torque from the motor M1. The second stage provides lower torque but higher speed from the motor M2. Such arrangement of power sources is achieved by carefully selecting of all the gear ratios in the train. The designed system is able to minimize the power usage of the IC engine and thus to minimize the exhaust gas emission, save cost of petrol as compared to normal petrol vehicle. It also provides a quite wide range of torque and speed values to drive the vehicle.