Abstract: A method and system for improving reliability of a vehicle crash discrimination system by minimalizing the effect of resonance inherently produced by structural elements of the vehicle includes using at least two accelerometers (18,20) mounted to different structural elements (22, 24) of the vehicle. The accelerometers are preferably mounted in close proximity to each other to produce similar acceleration data, but corrupted by dissimilar structural resonance. Signal analysis processing (36) is performed to extrapolate the common acceleration data to generate an output (38) substantially uncorrupted by structural resonance for use in the vehicle crash discrimination system. Detection of operability of the accelerometers (34) can also be performed to provide for switching to a backup mode filtering process (44) to insure operability of the discrimination system upon failure of one of the accelerometers.

Abstract: An acceleration sensor having a sensing mass supported relative to a frame by a plurality of beams having a plurality of resistors integral therewith. The resistance of the beam resistors varies as the sensing mass is displaced relative to the frame in response to acceleration of the frame in a direction generally normal to the plane of beam extension. The displacement of the sensing mass due to such acceleration produces a corresponding change in the output of a Wheatstone bridge incorporating the beam resistors in the legs thereof. At least one leg of the bridge additionally has a resistor of variable resistance in series with the beam resistor thereof, the resistance of which is controlled by a microprocessor, whereby the bridge output is adjusted to compensate for temperature effects and manufacturing tolerances.

Abstract: An air bag firing circuit comprises a firing path which includes in series a safing sensor, a squib, and a FET operated under microprocessor control in response to the output of an electronic crash sensor. A power supply maintains a known voltage across the firing path sufficient to explode the squib upon simultaneous "closure" of both the safing sensor and the FET operated by the microprocessor in response to crash sensor output. Normally, upon detection of a failure in the electronic crash sensor, its supporting electronics, or the FET actuated in response thereto, the microprocessor reconfigures the firing threshold of the safing sensor, as by applying a current to its integral test coil to increasingly bias the sensor's inertial mass away from its switch contacts. However, if a failure of the safing sensor is detected, reconfiguration of its threshold is inhibited notwithstanding the failure of other circuit components to prevent inadvertent deployment of the air bag.

Abstract: An acceleration sensor having a sensing mass supported relative to a frame by a plurality of beams having a plurality of resistors integral therewith. The resistance of the beam resistors varies as the sensing mass is displaced relative to the frame in response to acceleration of the frame in a direction generally normal to the plane of beam extension. The displacement of the sensing mass due to such acceleration produces a corresponding change in the output of a Wheatstone bridge incorporating the beam resistors in the legs thereof. At least one leg of the bridge additionally has a resistor of variable resistance in series with the beam resistor thereof, the resistance of which is controlled by a microprocessor, whereby the range of bridge outputs is adjusted to initially compensate for manufacturing tolerances and thereafter compensate for temperature effects and component aging.

Abstract: An acceleration sensor having a sensing mass supported relative to a frame by a plurality of beams having a plurality of resistors integral therewith. The resistance of the beam resistors varies as the sensing mass is displaced relative to the frame in response to acceleration of the frame in a direction generally normal to the plane of beam extension. The displacement of the sensing mass due to such acceleration produces a corresponding change in the output of a Wheatstone bridge incorporating the beam resistors in the legs thereof. At least one leg of the bridge additionally has a resistor of variable resistance in series with the beam resistor thereof, the resistance of which is controlled by a microprocessor, whereby the bridge output is adjusted to compensate for temperature effects and manufacturing tolerances.

Abstract: A firing circuit for deploying a pair of air bags comprises four circuit legs connected in parallel across a voltage supply via a diode shunted with a resistor. The first and second circuit legs each comprise in series a safing sensor, a squib, and a crash sensor, with each sensor being shunted by a like resistor whose resistance is substantially greater than the nominal resistance of the squibs. The third and fourth circuit legs each preferably comprise a resistor in series with a capacitor, with the resistance of the series resistor being significantly greater than that of the resistor shunting the grounded diode. Five bridges interconnect the four circuit legs so as to provide multiple firing paths and continued circuit viability notwithstanding the presence of one or more "faults" in the instant firing circuit.

Abstract: A firing circuit for deploying a pair of air bags comprises two circuit legs connected in parallel across a voltage supply. Each circuit leg comprises in series a safing sensor, a squib, and a crash sensor, with each sensor being shunted by a like resistor having a nominal resistance substantially greater than the nominal resistance of the squibs. Two separate diode bridges, each comprising a pair of oppositely biased diodes, bridge the circuit legs at junctions thereon between the safing sensors and the squibs, and the squibs and the crash sensors, respectively, to provide multiple firing paths for both squibs.