The hybrid module is designed to be both simple and robust: a disc-shaped electric motor is integrated in the drivetrain between the engine and the transmission. Two batteries are installed on the roof. Plus, there is also the voltage converter and an intelligent pulling-away management system with adapted engine control. The electric motor and voltage converter have their own coolant circuit.
In line with this, there is one important factor to bear in mind: just like the Mercedes-Benz passenger cars equipped with a hybrid drive, our hybrid module technology uses a separate 48-volt electrical system. That means that we completely do away with a complex high-voltage system and the associated safety requirements which such a system requires.
The technology operates as simply as it is designed: if the bus is coasting or braking, the electric motor works as a generator and creates electricity without using fuel to do so. The power generated in this way is stored as electrical energy.
In higher load situations, such as when pulling away, so-called boost phases, the electric motor assists the diesel or gas engine with additional torque by calling on the energy stored in the supercaps. This relieves strain on the combustion engine and thus also means lower fuel consumption.
The motors used in the hybrid module correspond to the output values of the combustion engines. The torque generated by the electric motor in the boost phase is used entirely for saving fuel. If sufficient energy is stored in the supercaps, the electric motor can also provide assistance during idling and thus also improves the efficiency of the combustion engine.