Patent ID: 7643920
Filing Date: 2010-01-05
Classification: B60R

Abstract:
1. A seat-belt pretensioner arrangement, the arrangement comprising a pretensioner having a tensioner motor for tensioning a seat-belt of a motor vehicle and having at least two different tension levels for tensioning the seat-belt, the at least two tension levels being greater than zero, a steering angle sensor for measuring the steering angle of a steering wheel, a velocity sensor for measuring the longitudinal velocity of the vehicle, and a control system, the control system including a first processor that receives input signals from the steering angle sensor and the longitudinal velocity sensor, a differentiator that differentiates input signals from the steering angle sensor with respect to time to provide a rate of change of steering wheel angle, and a second processor that in parallel with the first processor receives input signals from the differentiator and the longitudinal velocity sensor, each of the processors producing in parallel with each other one of a plurality of the outputs, each representing a desired seat-belt tension in response to the input signals, the output signals being generated when successive predetermined thresholds have been passed, each succeeding threshold being associated with a greater tension level than the preceding threshold, each threshold decreasing with increasing longitudinal velocity of the vehicle as measured by the longitudinal velocity sensor, the control system further including a selector which processes the respective outputs signals of the two processors and selects the higher of the two output signals from the processors, and, in response to the higher signal, instructs the tensioner motor to provide a desired degree of tension in the seat-belt.