Hybrid Drives for Passenger Cars and CVs

This allows for hybrid systems which further advance all applications, from passenger cars and trucks, buses and light commercial vehicles, right up to rail and special vehicles. And this is done reliably, since the new developments are based on well-proven driveline technology by ZF. Hybrid drives will be accepted by the market if the end customers benefit from improved profitability.

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

 

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

 

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

 

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.

Hybrid Power Classes

Full hybrid systems have the largest savings potential. Taking the lower purchasing cost as a calculation basis, however, the savings of micro and mild hybrid versions can also pay off for drivers or fleet owners.