Siemens VDO Developing Family of Hybrid Drives

26 September 2005

Siemens hybrid modules

Siemens VDO Automotive is developing a series of modular hybrid drives that will meet micro-, mild- and full-hybrid applications. The company is currently testing the micro and mild modules, and plans to have the full-hybrid drive with electrical outputs of up to 75 kW available by 2008.

The family approach strives to offer a set of modules—a kit of parts—from which vehicle manufacturers can select system solutions that best suit their advanced propulsion strategy needs.

Key to Siemens VDO’s approach are extensions to its Integrated Powertrain Management (IPM) system—originally developed to coordinate engine and transmission control—which now include electric drive system control, enabling the entire drive train to be managed.

The micro hybrid uses an a belt-integrated starter/alternator motor, control unit and intelligent belt tensioner to provide stop-start functionality. The system utilizes the existing 14-volt on-board power supply.

For the mild hybrid application, the electric motor is located on the crankshaft between the engine and the transmission. Depending on design, start-stop and energy recovery functions are available when braking. The electric motor provides tractive support to the engine during acceleration.

Siemens tests in current demonstration vehicles have shown reductions in fuel consumption of up to 6% on the micro hybrid and from 15%–18% on the mild hybrid.