Method and apparatus for varying the stiffness of a suspension bushing

A controllable suspension apparatus for controlling the relative displacement of a longitudinal suspension member in an motor vehicle relative to a chassis member of said vehicle, said controllable suspension apparatus comprising:

• a first structural component for connection to a suspension control arm of a vehicle;
• a second structural component for connection to a frame component of said vehicle;
• a magnetorheological elastomer interposed between and connected to said first and second structural components;
• an electrical coil operatively associated with said magnetorheological elastomer for generating a variable magnetic field dependent upon an electrical current supplied to said electrical coil;
• transmission control means for generating a transmission state signal;
• and
• suspension control means for generating said electrical current in response to said transmission state signal so as to vary the stiffness of said magnetorheological elastomer during a predetermined transmission event, thereby controlling the relative displacement of said first structural component with respect to said second structural component.

A method of controlling a variable stiffness suspension bushing having a magnetorheological elastomer disposed therein for controlling the relative displacement of a longitudinal suspension member relative to a chassis member in a motor vehicle, said method comprising the steps of:

• communicating a transmission state signal from a transmission control module to a suspension control module;
• determining from said transmission state signal a desired suspension bushing stiffness and generating an electrical current in response thereto;
• and
• communicating said electrical current to an electrical coil operatively associated with said magnetorheological elastomer, thereby generating a magnetic field so as to vary the stiffness characteristics of said magnetorheological elastomer to control the relative displacement of said longitudinal suspension member with respect to said chassis member.