Combustion engine operates as an auxiliary power unit and is mechanically disconnected from the wheels
On-board energy storage supplements traction power
The electric motor is directly connected to the drive shaft
No transmission required
Centralized system control to maximize energy flow from the battery and the engine
Stop-start capability allows all electric operation for demanding inner-city travel
In a series hybrid system, the combustion engine drives an electric generator instead of directly driving the wheels. The combustion engine with its attached generator works “as a power plant” to provide energy.
This energy is being supplemented by an energy storage unit.
The electric traction motor is responsible for driving the vehicle, either integrated into electric axles or connected to the drive shaft.
A transmission to switch gears is not needed as electric motors are efficient over a wide speed range.
An intelligent hybrid control system decides during the driving phase of the vehicle from where to feed the electric drive motor – either from the energy storage and / or from the generator.
During coasting, braking and stand-still where no traction power is required, it is possible to operate the auxiliaries completely from the energy storage, and shut down the combustion engine.
As soon as the hybrid control determines that more power is needed than is available from the energy storage – the combustion engine will be started via the generator in a very short time providing the required traction power.