Patent ID: 7272481

Claim:
An apparatus for correcting excessive yaw induced in a towing vehicle by a towed trailer, the apparatus comprising: a control valve adapted to be connected to the towing vehicle hydraulic brake system, said control valve operable to selectively actuate the towing vehicle wheel brakes; a plurality of vehicle parameter sensors adapted to be mounted upon the towing vehicle; and an electronic control unit also adapted to be mounted upon the towing vehicle, said electronic control unit electrically connected to said control valve and said vehicle parameter sensors, said control unit responsive to signals received from said vehicle parameter sensors to calculate an instability index for the combination of the towing vehicle and the towed trailer that is a function of the towing vehicle yaw rate and upon said instability index exceeding a predetermined instability threshold, said control unit is further responsive to cause said control valve to selectively apply the towing vehicle brakes to counter the towing vehicle yaw motion.