Airbag inflator

An airbag inflator (200, 300) for inflating an airbag has a tubular inflator housing (11 ) having a first end (A) and a second end (B). A gas release mechanism (80) has an exhaust port end or housing (85) at the first end (A) for releasing gas directly from the tubular inflator housing (11 ) to ambient air, bypassing the airbag. A heater assembly (2) containing a gas generant is located and attached at the second end (B). An igniter (3) ignites the heater assembly (2). A primary gas vent port (70) vents gas from the tubular inflator housing (11 ) into an airbag during normal deployment of theairbag. The gas release mechanism (80) has a passageway or opening (84) for exhausting gas from the tubular inflator housing (11 ) to an exhaust port (85). A rupturable seal (82, 83) seals the passageway or opening (84) of the gas release mechanism (80). An igniter 3 opens the seal (82, 83) to terminate or slow deployment and normal inflation of the airbag through the primary vent port (70).