Adaptive output fluid fueled airbag inflator

In an airbag system for a motor vehicle, the system comprising at least one airbag module containing at least one inflatable airbag and sensor means for sensing at least one airbag system operating condition selected from the group of ambient temperature, occupant presence, seat belt usage and deceleration of the motor vehicle, the improvement comprising:

• an adaptive output airbag inflator, coupled to the at least one airbag module, for generating an adaptive output of inflation gas to the airbag module, said adaptive output airbag inflator comprising:
• a first chamber wherein a supply of a first fuel in the form of a fluid and at least one oxidant are burned to produce combustion products including hot combustion gas and to increase the temperature and pressure within said first chamber, said first chamber adapted to open when a predetermined increase in pressure within said first chamber is realized, whereby at least a portion of the hot combustion gas is released from said first chamber,
• a second chamber containing a supply of pressurized stored gas, said second chamber in fluid communication with said first chamber upon the opening of said first chamber, the hot combustion gas released from said first chamber mixing with the pressurized stored gas to produce inflation gas and to increase the temperature and pressure within said second chamber, said second chamber adapted to open when a predetermined increase in pressure within said second chamber is realized after the hot combustion gas released from said first chamber mixes with the pressurized stored gas to produce the inflation gas, whereby at least a portion of the inflation gas is released from said second chamber to inflate the inflatable device,
• a first initiator device for initiating the combustion of the first fuel and the at least one oxidant, and
• a combination including,
• a second container for holding a supply of a second fuel in the form of a fluid, said second container adapted to open to be in fluid communication with said first chamber, and
• a second initiator device for initiating the combustion of the second fuel and the at least one oxidant;
• wherein, upon receipt by the module of a first level output signal from the sensor means, said first initiator device is actuated to initiate the combustion of the first fuel and the supply of the second fuel is retained in said second container, and
• wherein, upon receipt by the module of a third level output signal from the sensor means, both said first initiator device and said second initiator device are actuated to initiate the combustion of the first fuel and the second fuel, respectively.

A method of operation of an adaptive output airbag inflator in an airbag system for a motor vehicle, the system comprising at least one airbag module containing at least one inflatable airbag and sensor means for sensing at least one airbag operating condition selected from the group of ambient temperature, occupant presence, seat belt usage and deceleration of the motor vehicle, the airbag inflator having:

• a first chamber wherein a supply of a first fuel in the form of a fluid and at least one oxidant are burned to produce combustion products including hot combustion gas and to increase the temperature and pressure within the first chamber, the first chamber opening when a predetermined increase in pressure within the first chamber is realized, whereby at least a portion of the hot combustion gas is released from the first chamber,
• a second chamber containing a supply of pressurized stored gas, the second chamber in fluid communication with the first chamber upon the opening of the first chamber, the hot combustion gas released from the first chamber mixing with the pressurized stored gas to produce inflation gas and to increase the temperature and pressure within said second chamber, said second chamber opening when a predetermined increase in pressure within the second chamber is realized after the hot combustion gas released from the first chamber mixes with the pressurized stored gas to produce the inflation gas, whereby at least a portion of the inflation gas is released from the second chamber to inflate the inflatable device,
• a first initiator device for initiating the combustion of the first fuel and the at least one oxidant, and
• a combination including,
• a second container holding a supply of a second fuel in the form of a fluid, the second container adapted to open to be in fluid communication with the first chamber, and
• a second initiator device for initiating the combustion of the second fuel,
• wherein:
• 1) in response to receipt by the module of a first level output signal from the sensor means, said method comprises the steps of:
• burning the first fuel and the at least one oxidant in the first chamber to produce combustion products including hot combustion gas and increasing the temperature and pressure within the first chamber,
• opening the first chamber when a predetermined increase in pressure within the first chamber is realized to release hot combustion gas from the first chamber into the second chamber,
• mixing the released hot combustion gas with the pressurized stored gas in the second chamber to produce inflation gas,
• opening the second chamber when a predetermined increase in pressure within the second chamber is realized after the hot combustion gas released from the first chamber has mixed with the pressurized stored gas to produce the inflation gas to release at least a portion of the inflation gas from the second chamber to inflate the inflatable device;
• and
• 2) in response to receipt by the module of a third level output signal from the sensor means, said method comprises the steps of:
• burning the first fuel and the at least one oxidant in the first chamber to produce combustion products including hot combustion gas and increasing the temperature and pressure within the first chamber,
• releasing the second fuel into the first chamber from the second container,
• burning the second fuel and an oxidant in the first chamber to produce additional combustion products including additional hot combustion gas, the burning of the first fuel and the burning of the second fuel increasing the temperature and pressure within the first chamber,
• opening the first chamber when a predetermined increase in pressure in the first chamber is realized to release hot combustion gas from the first chamber into the second chamber,
• mixing the released hot combustion gas with the pressurized stored gas in the second chamber to produce inflation gas,
• opening the second chamber when a predetermined increase in pressure within the second chamber is realized,
• releasing combustion products produced from the combustion of the first fuel and additional combustion products produced from the combustion of the second fuel and the at least one oxidant from the first chamber into the second chamber,
• mixing at least the released combustion products with the pressurized stored gas in the second chamber to produce inflation gas,
• opening the second chamber when a predetermined increase in pressure within the second chamber is realized to release at least a portion of the inflation gas from the second chamber to inflate the inflatable device.