Patent ID: 6889613

Claim:
A variable output inflator comprising a housing having a combustion chamber therein and at least one port for expelling combustion gas from said combustion chamber; an initiator mounted on said housing for introducing a combustion gas into said combustion chamber; an injection piston slidably mounted in said combustion chamber of said housing for movement between an initial position and a second position in response to the introduction of a combustion gas into said combustion chamber from said initiator, said piston including a propellant chamber therein for containing a charge of liquid propellant therein and means communicating said propellant chamber with said combustion chamber to deliver liquid propellant thereto; and a magnetic control unit for controlling movement of said injection piston from said first position to said second position, said magnetic control unit including a sleeve within said housing coaxially of said injection piston to define a third chamber therebetween for receiving a magneto-rheological fluid, a core disposed in and concentrically spaced from said sleeve to define a gap therebetween communicating with said third chamber, and at least one electromagnetic coil for producing an electromagnetic field across said gap to affect the rheological properties of the magneto-rheological fluid in said gap whereby an increase in the electromagnetic field effects an increase in the flow resistance of the magneto-rheological fluid in said gap to slow the movement of said injection piston.