Pyrotechnic linear inflator

摘要

An inflator ( 10 ) for use in an inflatable vehicle occupant protection system. The inflator ( 10 ) includes a longitudinal enclosure ( 22 ) and a first gas generant ( 24 ) positioned along the enclosure ( 22 ). Enclosure gas exit apertures ( 40 ) are arranged along the enclosure ( 22 ) to enable fluid communication between the enclosure ( 22 ) and an exterior of the enclosure. and to provide controlled venting of combustion gases from the enclosure ( 22 ) as the first gas generant composition ( 24 ) burns, thereby controlling the speed and direction of combustion propagation of the first gas generant. Combustion of the first gas generant ( 24 ) results in an inflator housing internal pressure of at least a first predetermined minimum internal pressure. The second gas generant composition ( 91 ) is also configured to combust to generate inflation gas providing at least a second predetermined minimum internal pressure in the housing, the second predetermined minimum internal pressure being higher than the first predetermined minimum internal pressure. As combustion of first gas generant ( 24 ) nears completion, flame from combustion of the first gas generant composition ( 24 ) reaches the end ( 22 b) of the enclosure ( 22 ) and contacts the second gas generant composition ( 91 ), igniting the second gas generant ( 91 ) and producing a burst of gas and a resulting in an increase in inflator housing internal pressure. Gas exit apertures ( 20 ) along the housing ( 12 ) are sized such that the housing internal pressure is maintained at at least the first predetermined minimum level after passage of a predetermined time period after inflator activation.