Apparatus and method for detecting vehicle rollover having a discriminating safing function

An apparatus for detecting a vehicle rollover event comprising:

• a rollover sensor for sensing vehicle roll and providing a roll signal indicative of vehicle roll about a front-to-rear axis of the vehicle;
• a first accelerometer for sensing vehicle acceleration in a direction offset from the front-to-rear axis of the vehicle up to a maximum acceleration sensing level and providing a first acceleration signal indicative thereof;
• a second accelerometer for sensing vehicle acceleration in the offset direction at acceleration levels in excess of said maximum acceleration sensing level of said first accelerometer and providing a second acceleration signal indicative thereof;
• and
• controller for providing an actuation signal when the roll signal from the rollover sensor indicates a vehicle rollover condition and at least one of (i) the first acceleration signal indicates vehicle acceleration between a first threshold and a saturation threshold, which is less than said maximum acceleration sensing level, and (ii) the second acceleration signal indicates a vehicle acceleration greater than a second threshold which is greater than said saturation threshold.

An apparatus for detecting a vehicle rollover event comprising:

• a rollover sensor for sensing vehicle roll and providing a signal indicative of vehicle roll about a front-to-rear axis of the vehicle;
• safing circuit including a low g accelerometer for sensing vehicle acceleration in a direction offset from the front-to-rear axis of the vehicle up to a maximum acceleration sensing level and providing a first acceleration signal indicative thereof and a high g accelerometer for sensing vehicle acceleration in the offset direction at acceleration levels in excess of said maximum acceleration sensing level of said first accelerometer and providing a second acceleration signal indicative thereof;
• and
• controller for determining a rollover condition in response to the safing circuit and the rollover sensor.

A method for detecting a vehicle rollover event comprising the steps of:

• sensing vehicle roll and providing a roll signal indicative of vehicle roll about a front-to-rear axis of the vehicle;
• sensing vehicle acceleration in a direction offset from the front-to-rear axis of the vehicle up to a maximum acceleration sensing level and providing a first acceleration signal indicative thereof;
• sensing vehicle acceleration in the offset direction at acceleration levels in excess of said maximum acceleration sensing level and providing a second acceleration signal indicative thereof;
• comparing the first acceleration signal to a saturation threshold which is less than said maximum acceleration sensing level;
• selecting the first acceleration signal when the first acceleration signal is less than said saturation signal and selecting the second acceleration signal when the first acceleration signal exceeds said saturation signal;
• and
• determining a rollover condition in response to the selected one of the first and second acceleration signals and the sensed roll signal.

A method for detecting a rollover condition of a vehicle, said method comprising:

• sensing vehicle roll and providing a roll signal having a characteristic indicative thereof;
• sensing vehicle lateral acceleration in a lateral direction relative to a front-to-rear axis of the vehicle and providing an acceleration signal indicative thereof;
• and
• determining the occurrence of a vehicle rollover condition in response to the roll signal indicating a vehicle rollover condition and the acceleration signal having a value indicative of a non-impact vehicle rollover condition.