Hybrid & Alternative Fuels

Further tightening of CO2 and emission limits has triggered new powertrain concepts for the future. Electrification is an up-and-coming solution and is already in use today used on several platforms. By electrifying the powertrain of a vehicle, the internal combustion engine is either supported (hybrid concept) or fully replaced (BEV – battery electric vehicle) by an electric drivetrain. In the best case, this electric drivetrain is powered by a highly efficient Lithium-Ion battery.

The hybrid concept

The hybrid concept combines the established internal combustion engine with an additional electric drivetrain. The vehicle then operates to reduce fuel consumption and emissions significantly. In general, there are two possibilities to combine both drivetrains: “Serial Hybrid” or “Parallel Hybrid.” In the serial hybrid concept, the combustion engine is only used to generate electric power for the electric drivetrain, with no mechanical link between the combustion engine and the wheels. Examples of this layout include the Opel Ampera, the BMW i3 with Range-Extender, and the Volvo 7900 bus series. The internal combustion engine and the electric motor are connected to the wheels In the parallel hybrid concept. This opens a range of possibilities for optimizing the operation of both engines.

These figures depict the possible location of the electric motor within the complete drivetrain.

Depending on the mechanical location of the electric engine, different levels of assistance are possible. While a P0-configuration, generally operated at 48V, enables additional functions such as regenerative braking, torque smoothing, and power assist of the ICE, the P1 – P4 configuration is operated at much higher voltages (> 60V) and provides a pure electric driving experience.