Method and apparatus for sensing a vehicle crash
First Claim
1. An apparatus for controlling actuation of a vehicle air bag restraint system, said apparatus comprising:
- accelerometer means for sensing vehicle deceleration and for providing an electric signal having an RMS value functionally related to the sensed deceleration;
means for converting said electric signal provided by said accelerometer means into an RMS value, said RMS value being indicative of the sensed vehicle deceleration value;
means for comparing the converted RMS value against a predetermined value, said predetermined value being indicative of a predetermined deceleration value; and
means for actuating the air bag restraint system when said comparing means indicates the sensed value of the vehicle deceleration is greater than the deceleration value represented by the predetermined value.
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Accused Products
Abstract
A method and apparatus is disclosed for controlling actuation of an air bag restraint system. A deceleration sensor provides a signal having an RMS value which is functionally related to the value of the vehicle deceleration. An RMS thermal converter converts the deceleration signal into a converted voltage value. The converted voltage value is compared against a predetermined value, the predetermined value being indicative of a maximum deceleration value. If the converted voltage value of the deceleration signal exceeds the predetermined value, the air bag is actuated. A forced feedback arrangement uses a differential amplifier and a second, similar thermal sensor arrangement in a balance circuit so as to eliminate common-mode voltage errors. The feedback arrangement retains the converted value of the deceleration signal for a predetermined time period after the deceleration signal decays.
32 Citations
15 Claims
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1. An apparatus for controlling actuation of a vehicle air bag restraint system, said apparatus comprising:
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accelerometer means for sensing vehicle deceleration and for providing an electric signal having an RMS value functionally related to the sensed deceleration; means for converting said electric signal provided by said accelerometer means into an RMS value, said RMS value being indicative of the sensed vehicle deceleration value; means for comparing the converted RMS value against a predetermined value, said predetermined value being indicative of a predetermined deceleration value; and means for actuating the air bag restraint system when said comparing means indicates the sensed value of the vehicle deceleration is greater than the deceleration value represented by the predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for controlling actuation of a squib in a vehicle air bag restraint system, said apparatus comprising:
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accelerometer means for sensing deceleration of the vehicle and for providing an electric signal having an RMS value which is functionally related to the value of sensed deceleration; first heater means connected to said accelerometer means, said first heater means being energized by the electric signal from said accelerometer means and generating heat, the temperature of said first heater means being functionally related to the RMS value of the electric signal from said accelerometer means; first heat sensing means associated with said first heater means for providing an electric signal having a value which is functionally related to the temperature of said first heater means which, in turn, is functionally related to the RMS value of the output of the accelerometer means; and firing means for monitoring the electric signal from said first heat sensing means and for energizing the squib when the signal from said first sensing means indicates the deceleration of the vehicle is greater than a predetermined value. - View Dependent Claims (11, 12, 13)
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14. A method for controlling actuation of a vehicle air bag restraint system, said method comprising the steps of:
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a) sensing vehicle deceleration; b) providing an electric signal having an RMS value functionally related to the sensed deceleration; c) converting said provided electric signal into an RMS value; d) comparing the converted RMS value against a predetermined value, said predetermined value being indicative of a predetermined vehicle deceleration value; and e) actuating the air bag restraint system when said step of comparing indicates the value of sensed vehicle deceleration is greater than the deceleration value represented by the predetermined value.
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15. A method for controlling actuation of a squib in a vehicle air bag restraint system, said method comprising the steps of:
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a) sensing the amount of deceleration of the vehicle; b) providing an electric signal having an RMS value which is functionally related to the sensed amount of vehicle deceleration; c) thermally converting the electric signal indicative of the sensed deceleration into an electric signal having a converted value functionally related to the RMS value of the signal indicative of the sensed vehicle deceleration; d) comparing the converted value provided by the step of thermally converting against a predetermined value, said predetermined value being indicative of a predetermined maximum vehicle deceleration value; and e) connecting the squib to a source of electrical energy sufficient to ignite the squib when the step of comparing indicates the vehicle deceleration value is greater than the predetermined maximum value of vehicle deceleration.
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Specification