Tire condition monitoring system
AssigneeEaton Corporation
InventorAnthony P. Uzzo
Life of this patent
Estimating the term…
Abstract
Tire pressure monitors (10) are incorporated in vehicles (12) having pneumatic tires (15) to continuously or periodically measure air pressure within each tire and to alert the driver should the pressure in any of the tires fall below a predetermined value. A passive transponder (22) is affixed within the drop center (41) of each wheel (17) and includes a pressure sensing switch (36). An RF transmitter (46) centrally located within the vehicle body interrogates each transponder, either serially or simultaneously. Each transponder, in turn, reflects a predetermined harmonic of the RF signal back to a receiver (48) as a function of the state (open or closed) of its associated pressure switch. The receiver then outputs a signal to a processor/display unit (50) to activate an alarm or indicating device (58).
Claims18
A tire condition monitoring system comprising:
- transmitter means operative to generate an RF signal having a characteristic frequency f;
- a wheel-mounted passive transponder including,
- (i) first antenna means for receiving said RF signal,
- (ii) a nonlinear element in circuit with said first antenna means to effect a distortion of said RF signal characterized by a harmonic signal of a frequency nf, where n is a real number other than 1,
- (iii) second antenna means in circuit with said nonlinear element to radiate said harmonic signal, and
- (iv) sensor means operative to disable generation of said harmonic signal in response to variation in a monitored tire condition;
- and
- receiver means for providing a sensible condition signal in response to said harmonic signal.
A wheel-mounted passive transponder for use in a tire condition monitoring system of the type including a transmitter for generating an RF signal having a characteristic frequency f and a receiver for providing a sensible condition signal in response to variation in a monitored tire condition, said transponder comprising:
- first antenna means for receiving said RF signal;
- a nonlinear element in circuit with said first antenna means to effect a distortion of said RF signal characterized by a harmonic signal of a frequency nf, where n is a real number other than 1;
- second antenna means in circuit with said nonlinear element to radiate said harmonic signal;
- and
- sensor means operative to disable generation of said harmonic signal in response to variation in a monitored tire condition.
A tire pressure monitoring system for use with a vehicle having at least one pneumatic tire and associated mating wheel, said system comprising:
- transmitter means operative to generate an RF signal having a characteristic frequency f;
- a passive transponder mounted on said wheel and including,
- (i) a first antenna for receiving said RF signal,
- (ii) a nonlinear element in circuit with said first antenna to effect a distortion of said RF signal characterized by a harmonic signal of a frequency nf, where n is a real number other than 1,
- (iii) a second antenna in circuit with said nonlinear element to radiate said harmonic signal, and
- (iv) a tire pressure sensor operative to disable generation of said harmonic signal in response to variation in tire pressure from a predetermined set point;
- and
- receiver means for providing a sensible abnormal tire pressure condition signal in response to said harmonic signal.
Dependencies are inferred from the claim text.