Air bladder controlled hydraulic engine mount

Abstract

A hydraulic mount assembly is disclosed having a partition forming two hydraulic chambers and including a damping decoupler. A primary chamber is formed by an elastomeric member and a secondary chamber by a resilient diaphragm. During dynamic loading of the mount, fluid passes through an orifice between the two chambers of the mount causing expansion and contraction of the diaphragm. An expandable, pneumatic bladder is mounted within the primary chamber. A tube provides fluid communication between the bladder and the atmosphere. When a valve in this tube is open, air freely enters and escapes the bladder in symphony with the vibrating mount. Alternatively, the valve may be closed and a positive pressure provided to the bladder from a variable pressure fluid supply. By actively controlling bladder expansion and contraction in this manner, the dynamic rate of the mount assembly may be selectively reduced at relatively high vibration frequencies; that is, those over 20 Hz. Damping may also be reduced to provide a relatively soft mount for engine isolation. Further, by evacuating the bladder, a relatively hard mount may be provided exhibiting relatively high damping and high rate for better engine control. A control circuit with on-board transducers is also provided to monitor vehicle operating and road conditions and modulate the pressure in the bladder for maximum operating efficiency.