Abstract
A new two-motor hybrid system is developed to maximize powertrain efficiency. Efficiency of the system is drastically enhanced without any driving performance sacrifices by switching driving modes from "Hybrid Drive" to "EV (Electric vehicle) Drive" or "Engine Drive" according to the driving condition, along with the application of a series hybrid based system to make full use of high flexibility of engine operating points. Basic concepts of the maximization of powertrain efficiency including an applied system configuration and control technologies are discussed in this paper. Along with this system, a high capacity Li-ion battery and an on-board charger are installed in 2014 Honda Accord Plug-In to add practical plug-in HEV capabilities. Superior fuel economy is achieved with values of 46 MPG (Miles Per Gallon) in CS (Charge Sustaining) mode, 115 MPGe (Miles Per Gallon equivalent) in CD (Charge Depleting) mode and 13miles of AER (All Electric Range). MPGe is a unit of fuel economy for the alternate fuel vehicles such as plug-in hybrid electric vehicles or electric vehicles. The ratings are calculated by converting used electric energy into equivalent amount of gasoline.