Low tire warning system with axle torque signal

Abstract

A system and method that monitors four wheel sensors of an automotive vehicle to determine changes in the effective rolling radii of any wheel and a low pressure tire condition. Certain vehicle operating conditions, such as excessive or very low speeds, driven wheel torque, braking, and turns, are determined from the sensor outputs and are used to prevent erroneous detection of changes in effective rolling radius. Data from the sensors that is determined to be acceptable is accumulated over time as displacement values for each wheel. When the displacement values exceed a predetermined value, a metric function is used to compare differences detected in accumulated displacement values for the front pair of wheels and for the rear pair of wheels. If the difference between compared pairs of wheels is excessive, as compared with a predetermined baseline metric value, a low tire condition is detected. Further accumulation of instances where the metric indicates a detected condition, provides confidence that the condition actually exists and a warning is provided to the vehicle operator. Resetting of the system and the baseline metric is performed when the low tire condition is corrected or when the tires are checked and properly inflated.