Valve assembly for gas generating system

1. A gas generating system comprising:

a housing having a passage;

a forcing member positioned in the passage; and

a flowable material positioned in the passage to resist motion of the forcing member, wherein the flowable material flows out of the housing responsive to a force exerted on the forcing member by a gas, and wherein the forcing member divides the passage into a first portion and a second portion, the flowable material is positioned in the first portion of the passage, and wherein the gas generating system further comprises a seal for preventing flow of flowable material from the first portion to the second portion.

2. The gas generating system of claim 1 further comprising an opening formed in the housing to enable fluid communication between the first portion and an exterior of the first portion, through which flowable material is forced out of the first portion responsive to pressure exerted on the flowable material by the forcing member.

3. The gas generating system of claim 1 wherein the seal is coupled to the forcing member so as to move in conjunction with the forcing member.

4. The gas generating system of claim 1 wherein the first portion has a first volume prior to activation of the gas generating system, and wherein the flowable material occupies a second volume less than the first volume.

5. A gas generating system comprising:

a gas source;

a valve assembly for regulating a gas flow from the gas source, the valve assembly including:

a housing having a passage and at least one gas exit opening formed in the housing along the passage to enable fluid communication between the passage and an exterior of the housing;

the housing being coupled to the gas source so as to enable fluid communication between the gas source and the passage;

a forcing member positioned in the passage to form a cavity between the forcing member and the housing and to at least partially block a flow of gas through the at least one gas exit opening, the member being movable along the passage responsive to a flow of gas from the gas source;

a flowable material positioned in the cavity to resist motion of the forcing member responsive to the flow of gas; and

a seal formed between the housing and the forcing member to prevent flow of flowable material, out of the cavity.

6. The gas generating system of claim 5 wherein the flow of gas is in a first direction and wherein the seal is adapted to prevent the flow of flowable material in a second direction substantially opposite the first direction.

7. A gas generating system comprising:

a housing defining a passage;

a frangible seal coupled to the housing and adapted to prevent a flow of gas along the passage;

a flowable material positioned in the passage; and

means for fracturing the seal to form a first seal portion and a second seal portion, thereby releasing gas into the passage

wherein the released gas exerts a force on the second seal portion which is transmitted, via the second seal portion, to the flowable material to force the flowable material to flow out of the housing.

8. A vehicle occupant protection system comprising a gas generating system in accordance with claim 1 .

9. An airbag system comprising a gas generating system in accordance with claim 1 .

10. A gas generating system comprising:

a housing having a passage;

a forcing member positioned in the passage; and

a flowable material positioned in the passage to resist motion of the forcing member, wherein the flowable material flows out of the housing responsive only to a motion of the forcing member,

wherein a viscosity of the flowable material varies inversely with a temperature of the flowable material, and wherein the forcing member is configured to facilitate transmission of heat therethrough from the gas to the flowable material.