A Hybrid-Propulsion Powertrain with Planetary Gear Set for a 4WD Vehicle: Analysis of Power Flows and Energy Efficiency

A hybrid powertrain is proposed in this work as alternative to the traditional hybrid propulsion schemes. Using simulation models developed in a MATLAB -Simulink environment, the continuous behaviour of the vehicle is approximated as a series of discrete steps. During each step the components are assumed to be at steady state, and this assumption allows the use of power-usage or efficiency maps for the components, which are derived from steady-state tests in the laboratory. This main assumption, however, does not allow the investigation of detailed, short-duration drive train dynamics. The main advantages of this drive train are: • sluggish dynamic behaviour of the internal combustion engine (ICE), like in series powertrains; • traction torque provided directly by the ICE and by the electrical drive at the same time, like in parallel powertrains; • 4-wheel-drive layout. The main drawbacks are: • a slight increase of system’s weight due to the presence of a planetary gear train; • the vehicle can operate with electrical traction only but cannot operate with thermal traction alone.