ABSTRACT
As shown in Chapter 1, the fundamental challenge that limits powertrain efficiency is the varying vehicle speed and power demand in real time and the dependence of engine efficiency on speed and load conditions. Powertrain hybridization is one of the most effective ways for addressing this challenge. As the name suggests, a hybrid powertrain consists of the conventional internal combustion engine (ICE) and an alternative power source. Therefore, a hybrid transmission is needed to combine the power from the ICE and the alternative power source and send it to the wheels of the vehicle. Depending on the type of alternative power source and the architecture of the hybrid transmission, hybrid vehicles can be divided into different categories. Detailed discussions on the types of hybrid vehicles and the hybrid architectures will be provided in Sections 4.1.1 and 4.2.
