Method and apparatus for sensing a vehicle crash using a displacement velocity metric

An apparatus for sensing a vehicle crash comprising:

• acceleration sensing means for sensing vehicle acceleration and providing a signal indicative of crash acceleration;
• velocity determining means for determining a crash velocity value in response to said crash acceleration signal;
• displacement determining means for determining a crash displacement value in response to said crash acceleration signal;
• threshold determining means for providing a displacement threshold value functionally related to said determined crash velocity value;
• and
• means for comparing said crash displacement value against said displacement threshold value and providing an actuation signal when said crash displacement value is greater than said displacement threshold value.

A method for sensing a vehicle crash condition including the steps of:

• sensing vehicle crash acceleration;
• determining a crash velocity value from said sensed crash acceleration;
• determining a crash displacement value in response to said crash acceleration;
• selecting a displacement threshold value in response to said determined crash velocity value;
• comparing said determined crash displacement value against said selected displacement threshold value;
• and
• providing an actuation signal when said comparing step indicates said selected crash displacement value is greater than said determined displacement threshold value.