AC firing circuit for air bag systems
AssigneeSiemens VDO Automotive Corporation
InventorsCharles R. Cook, Jr., Horst Belau, Mark Andrew Parsons
Life of this patent
Estimating the term…
Abstract
A system for controlling air bag deployment in vehicles includes the capability of accommodating varying inductants values in the air bag circuit. Wire harnesses that couple air bag components have varying characteristics, such as length, which affect the inductants value of the circuit. The inventive arrangement utilizes charge and discharge times of at least one capacitor for measuring the inductants of a particular circuit. The system includes a controller that accommodates the inductants by introducing an appropriate delay in the firing circuit signal to operate the air bag.
Claims12
A system for controlling airbag deployment, comprising:
- a firing element that activates the airbag;
- a power source that supplies current pulses to the firing element;
- a capacitor coupled in series with the firing element;
- and
- a controller that controls the supply of current pulses to the firing element, the controller monitoring a charge time and a discharge time of the capacitor and using the charge or discharge time as an indicator of an inductance value associated with the firing element, the controller adjusting the supply of current pulses to accommodate the inductance.
A method of controlling airbag deployment in a system having an airbag firing element coupled in series with a capacitive element and an inductive circuit portion, comprising the steps of:
- powering the firing element using a series of current pulses;
- determining a time associated with a charging function of the capacitive element;
- and
- adjusting a frequency of the series of current pulses based upon the determined charge time.
A system for controlling airbag deployment, comprising:
- a firing element that activates the airbag;
- a power source that supplies current pulses to the firing element;
- a capacitor coupled in series with the firing element;
- and
- a controller that controls thc supply of current pulses to the firing element, the controller determining a discharge time of the capacitor and using the discharge time as an indicator of an inductance value associated with the firing element, the controller adjusting the supply of current pulses responsive to the discharge time of the capacitor to accommodate the inductance.
Dependencies are inferred from the claim text.