Front Engine Rear-Wheel Drive Vehicle Hybrid System (FR HEV).Front Engine Front-Wheel Drive Vehicle Hybrid System (FF HEV).One example is Nissan, with two variants: There are several OEMs which are using this hybrid powertrain architecture for their vehicle. (1)assuming the engine stop/start is performed with an additional electric starter The states of the clutches during each mode of the hybrid powertrain are summarised in the table below. From the implementation point of view, the second clutch is part of the transmission and not as a separate component. The second clutch, allows the electric machine to be disconnected from the drivetrain and let the vehicle coast during deceleration. Also, during deceleration phases, by disconnecting the engine, we can remove its braking effect and have higher efficiency for kinetic energy recuperation. The first clutch, between engine and electric motor, allows the engine to be disconnected from the drivetrain and drive in pure EV mode. Image: Parallel hybrid powertrain with two clutches For a rear-wheel drive (RWD) vehicle, a common hybrid powertrain architecture is using an electric machine between two clutches. In a parallel hybrid powertrain, both the internal combustion engine and electric motor can transmit torque to the driving wheel, in a sequence or in the same time. Parallel hybrid powertrain with two clutches In this article we are going to focus on the different types (architectures) of HEV powertrain, highlighting the working principle and the advantages/disadvantages compared with other types. energy recuperation during braking (regenerative braking)įor a detailed introduction in hybrid electric vehicles, types and their mode of operation, please read the article What is a Hybrid Electric Vehicle (HEV) ?.Most of the road vehicles with hybrid powertrain use an internal combustion engine (ICE) combined with an electric machine (EM).Ĭompared with a conventional vehicle, powered by an ICE, a hybrid electric vehicle is capable of performing these functions: A hybrid electric vehicle (HEV) is a vehicle which is using two sources of energy for propulsion, one of them being electrical energy.