Abstract: Measurements of wheel speed are compared to detect excessive wheel spin. An output of the wheel spin detector is supplied to a drive reducing device for reducing vehicle drive engine output in response to detection of excessive wheel spin. The reduced vehicle drive engine output is compared with a predetermined value by a subtracter. An estimate of surface friction is updated with a value dependent upon the output of the subtracter.

Abstract: In order to control wheel spin in a vehicle driven by an internal combustion engine, a spin calculator determines the amount of wheel spin and compares this with a target value. If the target value is exceeded, an engine controller reduces engine output demand, for instance by reducing the opening of a throttle. A fuelling controller forms a threshold value which is inversely dependent on the difference between the reduced engine output demand and the actual engine output demand. When the wheel spin exceeds the threshold value, the controller cuts off the supply of fuel for a predetermined pattern of engine fire events.

Abstract: A traction control system is provided for a vehicle having driven wheels driven via a limited slip differential. The amount of wheel spin of each driven wheel is compared with a threshold to detect excessive wheel spin. If excessive spin is detected for both driven wheels, an engine management system reduces the demand output of a vehicle engine. If excessive wheel spin is detected for only one of the driven wheels an engine output greater than the reduced demanded output is demanded so as to allow the limited slip differential to transfer torque to the other driven wheel.

Abstract: A wheel spin detector monitors the speeds of vehicle wheels and supplies a signal to an engine management system when excessive wheel spin is detected. The engine management system includes a fuel controller which, in response to the signal from the detector, reduces engine torque by inhibiting the supply of fuel to one or more cylinders of the engine such that either all cylinders are continuously fuelled or continuously unfuelled or one and only one cylinder is intermittently fuelled. When an unfuelled cylinder is fuelled again, the mixture supplied to it may be temporarily enriched.