Spare tire usage detection

An apparatus for determining whether a spare wheel (SP) has been moved from its stowage location to a rolling wheel (RW) location on a vehicle having multiple wheels, wherein each vehicle wheel includes a sender for transmitting a signal containing at least wheel identification (ID) and wheel motion status, comprising:

• a vehicle mounted receiver for receiving the signals broadcast by the senders;
• a processor coupled to the receiver for analyzing the received signals to determine each wheel ID and wheel motion status;
• a timer coupled to the processor for determining a predetermined time interval T;
• a memory coupled to the processor for storing information relating wheel ID to wheel location on the vehicle;
• wherein the processor analyzes the signals received from the wheels to determine whether the SP wheel has been rotating for a time T and if so, determines which remaining wheel is no longer rotating, then modifies the information stored in the memory so that the SP wheel ID becomes associated with the location previously occupied by the no longer rotating wheel and the ID of the no longer rotating wheel becomes associated with the SP storage location.

A method is provided for detecting when a spare wheel (SP) normally kept in a stowage location has replaced a normally rolling wheel on a vehicle, comprising:

• determining whether the SP is rolling;
• and if so
• starting an SP rolling timer and when the timer reaches predetermined time T;
• then
• examining motion status signal from remaining wheels to determine which wheel is now stopped, its ID and former location;
• and then
• associating a wheel ID for the SP with the former location of the stopped wheel and the stopped wheel ID with the stowage location of the SP.