Hybrid Architectures
There are three different hybrid architectures: parallel, serial, and power-split hybrid drives. The parallel structure allows for graded hybridization stages. In addition to the full hybrid, also micro and mild hybrid systems are possible.
Parallel hybrid drive
In the case of the parallel hybrid, the combustion-engine drive and the electric drive are connected in parallel. They can be used separately or together. The parallel hybrid can get by with only one electric motor, which saves costs. Moreover, the electric motor can be installed in the transmission housing in a space-saving manner. This has the advantage that the available transmissions can be used with their benefits regarding driving dynamics. System integration requires special know-how. Here, ZF's technological leadership for the entire driveline pays off. The parallel hybrid can also be designed as a micro, mild, and full hybrid and it is suitable for application in both passenger cars and commercial vehicles.
Serial hybrid drive
The serial hybrid drive has no mechanical link between the combustion engine and the wheels. In connection with a generator, the combustion engine solely has the purpose of generating power. The propulsive power flows from the generator to the drive shafts or directly to the wheels via one or more electric motors. This means that the combustion engine can always run at the ideal operating point, even if high speeds are required for starting and accelerating. ZF offers an electric portal axle for buses equipped with serial hybrid drives.
Power-split hybrid drive
The power-split hybrid drive works with two electric motors. Like in the serial hybrid, part of the combustion engines propulsive power is converted via these motors and fed to the output shaft; another part is transferred mechanically. Power distribution in the two paths depends on the operating condition. A planetary transmission serves as a switch for the distribution of mechanical and electric power. A central control unit issues commands for this complicated technology. In this complex system, the combustion engine can run in favorable operating points, and the electric motors can be designed with smaller dimensions compared to the serial hybrid.
Further information
Contact
Holger Kirsch
Trade Press Passenger Cars
Tel. +49 7541 77-2488
Fax. +49 7541 77-90 2488
E-mail:
holger.kirsch@zf.com
Annika Dingler
Trade Press Commercial Vehicles
Tel. +49 7541 77-7767
Fax. +49 7541 77-90 7767
E-mail:
annika.dingler@zf.com
