Multiple frequency passive hydraulic engine mounts English Free

Engine mounts are key elements inside vehicles, universally used for suspending the powertrain to the car body. They all basically consist of rubber and, now since decenies, often use an internal hydraulic system in order to reach the high loss factors wich are specified in the low frequency band, where attachment modes lie. Due to the challenging technical trade offs and needs for a better filtering of various powertrain vibrations sources, many different designs and variants are proposed for hydraulic engine mounts. They concern, for instance, geometrical optimizations of inertia tracks or orifices, decouplers for the higher frequency band, active and/or switchable systems, …
One particularly useful need is for significant loss factors at several frequencies and then, at the same time, overcoming effects from several suspension modes (e.g. up-down and roll movements). We describe a new original – passive – hydraulic engine mount, with different inertia tracks and specific designs, which results in such two (or more) damping peaks in the low frequency domain. A physical specific modelling and various numerical simulations (using a dedicated HBM code) are given, which illustrate the benefits of this technical concept. Practical applications are numerous, for instance for 3 cylinder powertrains NVH issues.

Keywords: suspension mount, vibration damping, numerical modelling, hydraulic systems, powertrain, automotive NVH.