Effects of viscoelastic properties of engine cover sealing system on noise and vibration attenuation

Automobile engine cam cover seals are made of elastomeric materials and used to seal the interfaces between cover and underlying structures. The design of engine cam cover seals has been traditionally focused on the sealability aspects. Recently, there has been additional demand that these seals be designed as vibration isolators to attenuate the radiated noise from the engine. To accomplish this goal, the frequency-dependent viscoelastic properties of the sealing components will have to be considered during the design process. This article examines the frequency-dependent viscoelastic properties of some commonly used elastomeric seals at various mounting configurations. An analytical spatial transmissibility method is used for evaluating the design of elastomeric sealing system for reducing vibration and radiated noise.