Freudenberg-NOK Sealing Technologies engineers have continuously contributed their expertise and resources to create diaphragms for extended maintenance cycles. Freudenberg-NOK has worked in close partnership with Polaris to engineer reliable diaphragms and introduce materials and design improvements to extend the life of these important components.

The snowmobile runs on a two-stroke engine, where the diaphragms (there are two per engine, one per cylinder) use cylinder pressure to actuate the variable exhaust valve mech­anisms. If the diaphragm fails, the variable exhaust valve will not actuate at the designated engine revolutions per minute (RPM). The result is that the engine will not reach its peak power and peak power RPM, which reduces the machine’s performance.

Polaris and Freudenberg-NOK have identified a further concern: Inferior diaphragms might fail completely, causing the variable exhaust mechanism to malfunction. When this occurs, the engine runs at a significantly reduced power level. If both diaphragms fail in rapid succession, the machine experiences further performance losses. Polaris and Freudenberg-NOK have collaborated on diaphragm designs that insure this will not happen.

Collaboration between Polaris and Freudenberg-NOK has resulted in design and production of a virtually maintenance-free diaphragm that lasts as long as the sled itself. Freudenberg-NOK optimized the design for Polaris in a number of important ways, including:

Incorporated fabric reinforced high temperature meta-aramid fabric (Nomex) to withstand extended high temperature in the exhaust system where the diaphragm is used and temperatures can often exceed 300°F even on very cold days;

Added a RFN coating to reduce friction by up to 70 percent, allowing the diaphragm to move effortlessly along the surfaces of the mating hardware;

Changed the design from a dome shape to a convoluted shape to decrease potential assembly issues, as well as allow for proper movement of the diaphragm and

Incorporated small rubber ribs to the fabric side to protect it from abrasion.

Together with extended maintenance cycles and improved performance in adverse conditions, Freudenberg-NOK has helped Polaris offer a product to customers that they can put full confidence in, no matter if the competition comes from another sled or tough terrain.