Tyre Pressure and Infra-Red Sensor (High Baud Rate)

The system consists of a powered pressure and temperature sensor with transmitter fitted to a wheel rim. This sends pressure and temperature data over an RF link to a compact receiver on the car. Sampling rates increase automatically when either a change in pressure is detected or when wheel inertia is detected. The system stops transmitting below a threshold pressure to preserve battery life. The receiver sends data to the car control via CAN.

Electrical

  • Supply voltage 2.8-3.6V (internal Lithium Thionyl Chloride battery)
  • Lifetime1 > 300,000 transmissions
  • Transmission count included in transmitted data
  • Battery voltage measured on full load
  • Transmission rate: governed by rate of change of pressure and rotation of the wheel. Structured to preserve battery life.

Tyre Pressure

  • Pressure range 4.4 to 30psi gauge (0.3 to 2.068 Bar)
  • Pressure resolution 0.01 psi/bit (0.69mBar/bit)
  • Pressure accuracy ±0.15psi (±10mBar) typical, ±0.3 psi (±20mBar) max

Tyre Temperature (IR Sensor)

  • Output voltage
    Target -20°COutput 0.30V
    Target +150°COutput 2.70V
  • Compensated temperature range +60°C to +120°C
  • Temperature resolution 0.052°C/bit
  • Temperature accuracy ±3°C
  • Repeatability ±1°C

Board Temperature

  • On-board KTY82-210 temperature sensor
  • Temperature sensor range -50°C to +150°C
  • Temperature resolution 0.17°C/bit

RF Specification

  • Compatible with High Baud rate TPR3
  • Modulation FM (FSK) encoded serial data
  • Nominal frequency 433.920MHz
  • Nominal baud rate 64kbps
  • Transmission range 15m (typ)
  • Each sensor transmits a unique serial number
  • All transmitted data is encrypted
  • Message content depends on type as follows:
    • Message Type 1 (3.7ms duration)
    • <Serial No>
    • <Board Temp>
    • <Pressure>
    • <TX count>
    • Message Type 2 (3.7ms duration)
    • <Serial No>
    • <Vbatt>(measured on full load)
    • <Tyre temp (IR sensor)>
    • <TX count>
    • Message Type 3 (3.7ms duration)
    • <Serial No>
    • <TX Life count>
    • <Tyre temp (IR sensor)>
    • <TX count>
Tx RateInertial switchPressureBoard TemperatureNominal Threshold dp/dt (mBar/s)Nominal Tx rate, Hz(s)Message type
0X<0.3Bar<40°C--0No TX (Internal sampling of pressure and Board temp at 0.4Hz)
1X>0.3Bar<40°C0.0167Hz
(60.0s)
1, 1, 2, 1, 1, 3 cyclically (Internal sampling of pressure and Board temp at 0.4Hz)
2LOW>0.3Bar>40°C0.010Hz
(10.0s)
1, 1, 2, 1, 1, 3 cyclically (Internal sampling of pressure and Board temp at 0.4Hz)
3HIGH>0.3BarX2.0Hz
(0.5s)
1, 1, 2, 1, 1, 3 cyclically
4X>0.3BarX1.52.0Hz
(0.5s)
1, 1, 2, 1, 1, 3 cyclically

Rate 0: applies when the pressure is <0.3 Bar gauge and Board Temperature is less than 40°C. Sensor does not transmit but continues to sample the pressure and board temperature.

Rate 1: The IR element will not be enabled to preserve battery life. Therefore the IR measurements when operating in rate1 will not be valid.

Before the sensor changes to a lower Tx rate it will transmit 10 messages at the higher rate.

Rates quoted are for Vsupply = 3.6V and 25°C. Rates slow down linearly with increasing temperature and reducing Vsupply. Rates are ≈ 0.63 quoted values under combined worst case condition of Vsupply = 2.5V and temperature = 135°C.

Data Supplied

The following data is supplied on data disc for each sensor:

  • Full 16-bit ID serial number
  • Sensor output at two pressure set points measured at two temperature set points

Mechanical

  • Sensor incorporates Schrader valve in separate valve stem for tyre inflation
  • Sensor weight <45g
  • Valve stem 6AL4V Titanium (Ti Nitride coating)
  • Sensor housing PEEK GF30
  • 3/8UNF stud nut max torque 25Nm (18.4lbf/ft)
  • M6 sensor nut max torque 8Nm (5.9lbf.ft)

Environmental

  • Resistant to standard Motorsport fluids
  • Operating temperature2 +10 to +135°C
  • Vibration 50 to 2500Hz @ 40g eight hours per axis
  • Shock 50g(max), 1/2sine for 11ms, five times per axis

1 Assuming the sensor is subjected to the following conditions leading to and during a Formula1 race weekend:

  • Rate0 – 240 Hours
  • Rate1 – 91 Hours
  • Rate2 – 4 Hours
  • Rate3 or 4 – 1 Hour

2 Absolute maximum operating temperature +150°C. Operating the sensor above 135°C will reduce the life of the battery.

Tyre Pressure and Infra-Red Sensor Mechanical Drawing
DescriptionInertial Switch AxisOrdercode
Combined Tyre Pressure and Infra Red SensorYO 030 330 046 075
Combined Tyre Pressure and Infra Red SensorZO 030 330 046 095

Sensor housing and stud designs can be tailored to suit individual wheel rims. The outline drawings shown within this product summary are examples for which other bespoke designs may be based upon. Please contact MES for further assistance.

Tyre Pressure and Infra-Red Sensor Stud Mechanical Drawing
DescriptionDimension ADimension BDimension COrdercode
Valve stud3mm26mm4mmO 030 330 990 018
Tyre Pressure and Infra-Red Sensor Stud Mechanical Drawing
DescriptionDimension ADimension BDimension COrdercode
Valve stud kit (O-ring, M6 K-nut, Schrader valve insert)22mmØ16mm30°O 030 330 990 023

Application Note

Pressure Sensors

Installation Note

Pressure Sensors

Contacts

Technical Support

support@mclaren.com