Abstract: A method of detecting the presence of an undersized, e.g., mini-spare, or an underinflated, oversized or overinflated tire or tires on a passenger motor vehicle improves operation of traction control, stability and anti-lock brake systems by compensating for such operating anomalies. The method includes the steps of sensing the steering angle, sensing the actual rotational speeds of each wheel, determining the actual vehicle speed, calculating each expected wheel speed based upon the sensed steering angle and wheel speeds, calculating each tire diameter based upon the calculated wheel speeds and, finally, determining whether such diameters are within various defined ranges which permit normal operation, permit reduced function operation, or require system shut down.

Abstract: Clutch control systems for a power take-off system of a vehicle, such as those employing all-wheel and four-wheel drive systems. The control system calculates the temperature of the clutch system, based on one or more vehicle operational parameters. If the clutch system reaches a pre-determined temperature limit, the control system selectively stops the operation of the clutch system until the clutch temperature drops below the pre-determined temperature limit. The control system includes an electronic control unit, e.g., a computer or microprocessor, that calculates and/or processes one or more vehicle operational parameters, including, but not limited to: (1) clutch input and output speeds; (2) slip across the clutch; (3) clutch torque; (4) current clutch power; (5) accumulated clutch power; (6) temperature delta (i.e., change) of the clutch; and (7) clutch temperature.