Tire pressure monitoring system
View Patent ↗A vehicular tire pressure monitoring system, including a transponder unit ( 10 ) for each tire to be monitored, the transponder unit having an incorporated RF transmitter ( 12 ) and being physically associated with the tire to be monitored. A pressure sensor for each tire to be monitored is connected to circuitry in a corresponding transponder unit. An interrogator unit ( 7 ) is associated with each transponder unit and physically mounted on a vehicle in proximity to a wheel ( 9 ) whereon a tire to be monitored is mounted. A central RF receiver ( 4 ) for all transponder units is provided. Each transponder unit is inductively coupled with an associated interrogator unit and includes an electric charge accumulation element adapted to be charged by energy inductively supplied from the associated interrogator unit in a first mode of operation, and the charge accumulation element providing a power supply to the RF transmitter of the transponder unit in a second mode of operation.
1. A vehicular tire pressure monitoring system comprising:
a transponder unit for each tire to be monitored, the transponder unit having an incorporated RF transmitter and being physically associated with the tire to be monitored;
a pressure sensor for each tire to be monitored and connected to circuitry in a corresponding transponder unit;
an interrogator unit associated with each transponder unit and physically mounted on a vehicle in proximity to a wheel whereon a tire to be monitored is mounted; and
a central RF receiver for all transponder units; wherein
each transponder unit is inductively coupled with an associated interrogator unit and includes an electric charge accumulation element adapted to be charged by energy inductively supplied from the associated interrogator unit in a first mode of operation, and the charge accumulation element providing a power supply to the RF transmitter of the transponder unit in a second mode of operation, wherein the interrogator units are mounted in respective wheel housings of the vehicle and the charge accumulation elements are charged during rotation of respective wheels, and, wherein the interrogator units are mounted on a liner of plastics material and include an antenna that extends along a major part of the peripheral extension of the liner with respect to vehicle rotation.
2. A vehicular tire pressure monitoring system comprising:
a transponder unit for each tire to be monitored, the transponder unit having an incorporated RF transmitter and being physically associated with the tire to be monitored;
a pressure sensor for each tire to be monitored and connected to circuitry in a corresponding transponder unit;
an interrogator unit associated with each transponder unit and physically mounted on a vehicle in proximity to a wheel whereon a tire to be monitored is mounted; and
a central RF receiver for all transponder units; wherein
each transponder unit is inductively coupled with an associated interrogator unit and includes an electric charge accumulation element adapted to be charged by energy inductively supplied from the associated interrogator unit in a first mode of operation, and the charge accumulation element providing a power supply to the RF transmitter of the transponder unit in a second mode of operation, wherein each transponder unit includes
a) an integrated circuit with
a programmable control unit,
a rectifier connected to LF input terminals and having an output,
a power terminal connected to the output of the rectifier,
at least one analog input terminal for a pressure sensor, and
an encoder with an input connected to an output of the programmable control unit and an output connected to an output terminal of the integrated circuit;
b) a resonant circuit with an inductor antenna and a capacitor, connected to the LF input terminals of the integrated circuit;
c) a charge accumulation capacitor connected to the power terminal of the integrated circuit; and
d) an RF transmitter with a signal input coupled to the output terminal of the integrated circuit, a supply input connected to the charge accumulation capacitor and an output connected to an antenna.