| 摘要 |
PURPOSE: To certainly sense gas leakage at an air bag device. CONSTITUTION: A driver/passenger restraining device (air bag) 10 for car is equipped with a vessel 14 to accommodate a mixture gas 18 for generating the heat emitting reaction, and a restraining tool (air bag element) 12 is inflated by the mixture gas discharged from the vessel. A sensor element 44 having electroconductivity is installed in a capsule 40 surrounding a part of the vessel, and when gas leaks from the vessel, the sensor element 44 is exposed to the gas to cause change in its electric resistance. By a timing circuit 52, the current from a power supply is supplied to the sensor element 44 intermittently, and the change in the electric resistance of the sensor element 44 is sensed by an electric circuit 46, and the result is displayed by an indicator means 54. The off period of the timing circuit 52 is set to over a certain lever, for example 24hr, so that the leaking gas is accumulated in the neighborhood of the sensor element 44 in the capsule 40. At the same time, the On period is made around several micro-seconds so as to lessen the consumption of the leaking gas by the sensor element 44, and it is ensured that the leaking gas is sensed certainly.
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