Trw Limited

Tien Hsiung Lee

Chek-Peng Foo

Paul Leo Sumner

Huahn Fern Yeh

Anne Marie Shields

An apparatus and method for controlling an actuatable occupant restraint device having a plurality of actuatable stages ( ), the apparatus including a crash sensor ( ) for sensing crash acceleration and providing a crash acceleration signal indicative thereof. A controller ( ) determines a velocity value ( ) and a displacement value ( ) from the crash acceleration signal. A safing function controls enabling and disabling of a deployment control circuit in response to the determined velocity ( ) and displacement ( ) values. A displacement based velocity threshold ( ) and a displacement threshold value ( ) define an immunity box. The velocity threshold value ( ) varies as a step function of displacement. If the velocity/displacement values are within the immunity box, the safing function is in a disabling condition. If either value is outside of the immunity box, the safing function is in an enabling condition. A side impact sensor ( ) and side impact crash event circuit ( ) determine if a side impact crash event is occurring. If a side impact crash event is occurring, the threshold values ( ) of the immunity box are adjusted.

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Ann Arbor, MI, United States of America

Tien Hsiung Lee