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ZF Friedrichshafen AGKonzernkommunikation Corporate Communications D-88038 Friedrichshafen Deutschland · Germany

Active Engine Mounts from ZF: Tranquility in the Driveline Both high- and low-frequency vibrations are optimally

isolated Vibration and noise comfort in the passenger cell Important element in engine downsizing and cylinder

shutoff

Active engine mounts optimally dampen and isolate the vibrations, noises, and movements generated by the car's engine in every combustion engine operating mode. This noticeably enhances comfort for the vehicle occupants. But it is also a key element when making engine downsizing and vehicles with electronic cylinder shutoff – which constantly change their vibration behavior – acceptable for occupants and hence marketable.

Rubber-metal components have always played an important role in the driveline. In order to mount the engine-transmission unit in the vehicle in such a way that it does not generate any vibrations or noises which are annoying for the passengers, the ZF Group offers a broad range of powertrain mounts: Conventional or hydraulic engine mounts, transmission mounts and torque supports are the connections that provide the mounting of the engine block and transmission on the vehicle body. These mounts, which are inconspicuous at first glance, have a broad range of tasks that considerably influence the comfort and dynamic driving features of a vehicle: They must prevent unbalanced engine torque – e.g. when idling – from being transferred to the body as noise or vibrations. They also have to isolate high-frequency vibrations which are generated at high speeds when the vehicle is in operation. In addition, they also have to prevent excitations emanating from the road surface, so that the engine-transmission unit does not cause the entire vehicle to sway in an undesired and uncomfortable motion (“stuttering”).

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ZF Friedrichshafen AGKonzernkommunikation Corporate Communications D-88038 Friedrichshafen Deutschland · Germany

This conflict of aims was previously only able to be solved by a compromise in which the rubber-metal powertrain mounts and hydraulically damping mounts were set ex factory either towards comfort (noise absorption primarily in idling speed) or towards driving dynamics (prevention of mount movement through excitation caused by the road surface). This compromise is determined during the development phase for each vehicle class and for various engines within a vehicle class. An end to compromise Active engine mounts from ZF bring to an end the search for a compromise when mounting the engine. When the vehicle is in operation, the active ZF module functions as a hydraulic engine mount. In idling speed, an active membrane controls the pressure in the working chamber so that low-frequency excitations are isolated much more effectively than the characteristic of the hydraulic mount which is designed more towards driving dynamics. For the passengers, this offers considerably greater comfort. The active engine mount from ZF is an important addition especially for the increasing number of passenger cars with downsizing engines or electronic cylinder shutoff. As the number of cylinders is reduced, the engine runs less smoothly. Hence the level of vibration transferred from the engine block to the body increases. This "NVH" (Noise, Vibration and Harshness) behavior varies greatly with turbocharged engines with a small number of cylinders, depending on the engine speed and driving situation. Finding the right characteristic for a hydraulic or conventional engine mount in this situation is virtually impossible. By contrast the active engine mount with its broad characteristic map isolates any oscillations and vibrations that occur.

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ZF Friedrichshafen AGKonzernkommunikation Corporate Communications D-88038 Friedrichshafen Deutschland · Germany

Caption: Active engine mount from ZF: An active membrane controls the pressure in the working chamber and consequently optimally dampens the low-frequency vibrations. When the vehicle is in operation, the mount automatically switches back to the optimal hydraulic mount for driving dynamics. Photo: ZF Press Contact: Corina Dreher, Trade Press, Tel. +49 7541-77 8238, Fax: +49 7541-77 908238, e-mail: corina.dreher@zf.com Robert Buchmeier, Trade Press, Tel. +49 7541 77-2488, Fax: +49 7541-77 902543, e-mail: robert.buchmeier@zf.com Thomas Wenzel, Senior Manager Product Communication and Trade Press, Tel. +49 7541-77 2543, Fax: +49 7541-77 902543, e-mail: thomas.wenzel@zf.com ZF is a global leader in driveline and chassis technology with 121 production companies in 26 countries. In 2012, the Group achieved a sales figure of about EUR 17.4 billion with approximately 75 000 employees. In order to continue to be successful with innovative products, ZF annually invests about five percent of its sales (2012: EUR 861 million) in research and development. ZF is one of the ten largest automotive suppliers worldwide. For further press information and photos please visit: www.zf.com