System, method and apparatus for monitoring tire inflation pressure in a vehicle tire and wheel assembly

A method of measuring inflation pressure of a pneumatic tire of a tire and wheel assembly on a vehicle having multiple tire and wheel assemblies comprising the steps of:

• (a) monitoring a rotational characteristic of each tire and wheel assembly on said vehicle,
• (b) comparing the rotational characteristic of one tire and wheel assembly monitored in step (a) to a reference,
• (c) indicating tire inflation pressure of said one tire and wheel assembly as a function of a difference between its rotational characteristic and said reference, and
• (d) defining said reference as a function of the rotational characteristic of at least one of the other tire and wheel assemblies on said vehicle monitored in said step (a) and as a function of a measure of speed of said vehicle,
• said reference also including a table relating inflation pressure of said one tire and wheel assembly to the rotational characteristics of such tire and wheel assembly and vehicle speed, and wherein said step of comparing said rotational characteristic includes accessing said table as a function of such rotational characteristic and of said measure of vehicle speed.

A method of measuring the inflation pressure of a pneumatic tire of a tire and wheel assembly on a vehicle having multiple tire and wheel assemblies comprising the steps of:

• (a) monitoring a rotational characteristic of each tire and wheel assembly on said vehicle,
• (b) comparing the rotational characteristic of one tire and wheel assembly monitored in said step (a) to a reference,
• (c) indicating tire inflation pressure of said one tire and wheel assembly as a function of a difference between its rotational characteristic and said reference, and
• (d) defining said reference in part as a function of at least one of the rotational characteristics of the other tire and wheel assemblies monitored in said step (a) and in part independent of such rotational characteristics,
• said reference including a measure of the speed of said vehicle, and
• said reference also including a table relating inflation pressure of said one tire and wheel assembly to the rotational characteristics of such tire and wheel assembly and vehicle speed, and wherein said step of comparing said rotational characteristic includes accessing said table as a function of such rotational characteristics and of said measure of vehicle speed.

A system for use on vehicles having road wheels with pneumatic tires, said system comprising:

• a plurality of at least two sensing means, each such sensing means being associated with a vehicle road wheel, each such sensing means producing, as an output, a signal that is a measure of rotational speed of its respective road wheel,
• indicating means arranged to provide information to the driver of said vehicle, and
• computer means operably associated with said sensing means and said indicating means,
• said computer means being constructed to perform at least one of the functions of:
• (a) selecting a wheel speed signal or signals to be used for determining inflation pressure of one of the tires of the vehicle, determining a value which represents the inflation pressure of such tire, and signaling at said indicating means when this value falls below a predetermined level, and
• (b) selecting a wheel speed signal or signals to be used for determining inflation pressure of one of the tires of the vehicle, determining a value which represents the inflation pressure of such tire, and signaling this value at said indicating means,
• wherein said computer means includes a database of values relating inflation pressures of the tires to rotational speeds of said road wheels and to the speed of said vehicle, and wherein this database is accessed in making the determinations specified in steps (a) and (b).

A system for use on vehicles having road wheels with pneumatic tires, said system comprising:

• a plurality of at least two sensing means, each such sensing means being associated with a vehicle road wheel, each such sensing means producing, as an output, a signal that is a measure of rotational speed of its respective road wheel,
• indicating means arranged to provide information to the driver of said vehicle,
• computer means operably associated with said sensing means and said indicating means, and
• means for determining tire inflation pressure at said road wheels and inputting information indicative thereof into said computer means,
• said computer means being constructed to perform at least one of the functions of:
• (a) selecting a wheel speed signal or signals to be used for vehicle speed determination, determining a value which represents the speed of the vehicle, and signaling this value at said indicating means, and
• (b) selecting a wheel speed signal or signals to be used for determination of distance traveled, determining a value which represents distance traveled by the vehicle, and signaling this distance at said indicating means,
• wherein said computer means includes a database of values relating inflation pressures of the tires to rotational speeds of said road wheels and to the speed of said vehicle, and wherein this database is accessed in making the determinations specified in steps (a) and (b).

A system for use on vehicles having road wheels with pneumatic tires, said system comprising:

• a plurality of at least two sensing means, each such sensing means being associated with a vehicle road wheel, each such sensing means producing, as an output, a signal that is a measure of rotational speed of its respective road wheel,
• indicating means arranged to provide information to the driver of said vehicle, and
• computer means operably associated with said sensing means and said indicating means,
• said computer means being constructed to perform at least one of the functions of:
• (a) determining a value which represents tire inflation pressure and signaling at said indicating means when this value falls below a predetermined level, and
• (b) determining a value which represents tire inflation pressure and signaling this value at said indicating means,
• and at least one of the additional functions of:
• (c) determining a value which represents vehicle speed and signaling this value at said indicating means, and
• (d) determining a value which represents distance traveled by the vehicle and signaling this value at said indication means,
• wherein said computer means includes a database of values relating inflation pressures of the tires to rotational speeds of said road wheels and to the speed of said vehicle, and wherein this database is accessed in making the determinations specified in steps (a), (b), (c) and (d).

A system for use on vehicles having road wheels with pneumatic tires, said system comprising:

• a plurality of at least two sensing means, each such sensing means being associated with a vehicle road wheel, each such sensing means producing, as an output, a signal that is a measure of rotational speed of its respective road wheel,
• indicating means arranged to provide information to the driver of said vehicle, and
• computer means operably associated with said sensing means and said indicating means,
• said computer means being constructed to perform at least one of the functions of:
• (a) selecting a wheel speed signal or signals to be used for determining inflation pressure of one of the tires of the vehicle, determining a value which represents the inflation pressure of such tire, and signaling at said indicating means when this value falls below a predetermined level, and
• (b) selecting a wheel speed signal or signals to be used for determining inflation pressure of one of the tires of the vehicles, determining a value which representing the inflation pressure of such tire, and signaling this value at said indicating means,
• wherein said computer means is arranged to perform, from time to time, a routine wherein calibration data, relating the current inflation pressures of the specific tire and wheel assemblies currently mounted on the vehicle to the rotational speeds of said road wheels and to the speed of said vehicle, is calculated and is stored in the system, and wherein said determinations are thereafter computed as a function of the most recent calibration data.

A system for use on vehicles having road wheels with pneumatic tires, said system comprising:

• a plurality of at least two sensing means, each such sensing means being associated with a vehicle road wheel, each such sensing means producing, as an output, a signal that is a measure of rotational speed of its respective road wheel,
• indicating means arranged to provide information to the driver of said vehicle,
• computer means operably associated with said sensing means and said indicating means, and
• means for determining current tire inflation pressure at said road wheels and inputting information indicative thereof into said computer means,
• said computer means being constructed to perform at least one of the functions of:
• (a) selecting a wheel speed signal or signals to be used for vehicle speed determination, determining a value which represents the speed of the vehicle, and signaling this value at said indicating means, and
• (b) selecting a wheel speed signal or signals to be used for determination of distance traveled, determining a value which represents distance traveled by the vehicle, and signaling this distance at said indicating means,
• wherein said computer means is arranged to perform, from time to time, a routine wherein calibration data, relating the current inflation pressures of the specific tire and wheel assemblies currently mounted on the vehicle to the rotational speeds of said road wheels and to the speed of said vehicle, is calculated and is stored in the system, and
• wherein said determinations are thereafter computed as a function of the most recent calibration data.

A system for use on vehicles having road wheels with pneumatic tires, said system comprising:

• a plurality of at least two sensing means, each such sensing means being associated with a vehicle road wheel, each such sensing means producing, as an output, a signal that is a measure of rotational speed of its respective road wheel,
• indicating means arranged to provide information to the driver of said vehicle, and
• computer means operably associated with said sensing means and said indicating means,
• said computer means being constructed to perform at least one of the functions of:
• (a) determining a value which represents tire inflation pressure at at least one of said road wheels and signaling at said indicating means when this value falls below a predetermined level, and
• (b) determining a value which represents tire inflation pressure at at least one of said road wheels and signaling this value at said indicating means,
• and at least one of the additional functions of:
• (c) determining a value which represents vehicle speed and signaling this value at said indicating means, and
• (d) determining a value which represents distance traveled by the vehicle and signaling this value at said indicating means,
• wherein said computer means is arranged to perform, form time to time, a routine wherein calibration data, relating the current inflation pressures of the specific tire and wheel assemblies currently mounted on the vehicle to the rotational speeds of said road wheels and to the speed of said vehicle, is calculated and is stored in the system, and wherein said determinations are thereafter computed as a function of the most recent calibration data.