Patent ID: 8155841

Claim:
A crash detection arrangement, to be installed in a motor vehicle, for detecting a crash and providing a control signal for controlling a safety device in the event that a crash is detected, the arrangement comprising an accelerometer and a control unit, the accelerometer being arranged to supply a signal to the control unit which is indicative of the acceleration of the vehicle, the control unit is configured to: continuously update a classification parameter based on the value of the signal from the accelerometer over a sliding time window spanning a fixed classification time period, determine that a predetermined initiation criterion independent of the classification parameter is fulfilled; upon determining that the initiation criterion was fulfilled, modify a threshold value of a crash evaluation algorithm in dependence upon the classification parameter, wherein the classification parameter is the classification parameter last calculated from a time window that includes an interval of time before the initiation criterion was fulfilled, and wherein the threshold value is set to be equal to a low threshold value when the classification parameter indicates that the rise in acceleration before fulfillment of the initiation criterion is relatively fast, and to be equal to a high threshold value when the classification parameter indicates that the rise in acceleration before fulfillment of the initiation criterion is relatively slow; and determine an evaluation parameter with the crash evaluation algorithm upon fulfillment of the initiation criterion; determine that the evaluation parameter has exceeded the threshold value; and produce the control signal upon determining that the evaluation parameter has exceeded the threshold value.