Achieving accurate tire-carcass temperature measurement is a problem because other components and systems may distort readings. But now Beru f1systems has revealed details of a new infrared (IR) sensor called DigiTyre IR that it claims can record accurate tire-carcass temperature, avoiding the effects of heat soak from the wheel rim and brakes. It also records air pressure and temperature.
Most tire-temperature sensors are fitted to the rim as part of the valve that risks being affected by heat soak from other sources, said Managing Director John Bailey. "However, our new system uses IR sensors to measure the inside temperature of the tire carcass itself, not just air temperature. Engineers will now be able to correlate accurate tire-carcass temperature to wear, traction, and loading. This inside measurement is key as it identifies the true tire temperature, not just the surface that is in contact with the road."
The system has been used for tire testing by two Formula One race teams and is expected to be used by others, said Bailey. It is set to be used in races from 2009 when slick tires are introduced and testing is dramatically reduced. It could also find applications for road tire testing and development.
The earliest possible warning to a race driver—and vehicle monitoring team—of imminent tire deflation is a crucial issue, and information about the tire-carcass temperature could help to identify tire deflation more quickly.
"There is a chain of events when a tire deflates," explained Bailey. "If a tire develops a puncture, tire and air temperatures rise, with a short lag between the two. Traditional systems only measure air temperature; our new system will receive data about changes to the carcass temperature, so a puncture can be identified earlier."
He added that DigiTyre IR offers resolution of 0.25ºC (0.45°F) and accuracy of 0.5ºC (0.9°F) across an extended temperature range of -40ºC to +215ºC (-40°F to +419°F).
The wheel sensor transmits pressure, air, and tire temperature at 1 Hz, via antennae to the ECU. Existing Beru f1systems’ customers can upgrade their existing TPMS with new wheel electronics and software.
The system is also compatible with CAN bus, simplifying integration to loggers. The sensor includes an LF (low-frequency) receiver, allowing engineers using remote devices to receive data. The receiver also allows tire temperature and pressure to be monitored when wheels are being checked on dynamometers or test beds.
"DigiTyre IR is expected to appeal to motorsport users where cost-cutting measures and changes to technical regulations are posing new engineering challenges," said Bailey. Changing F1 rules for 2009 means a very significant reduction in F1 testing together with the introduction of slick tires, driving demand for trusted data.
The new system was checked out by F1 teams in the first winter tests for the 2009 season as teams gained experience with slick tires. "Engineers are discovering the new tires, which are the same width as outgoing grooved tires, are generating lots of front-end grip. With more data, they will be better armed to make setup decisions," stated Bailey. "Testing reductions make track time valuable and engineers will want to acquire as much knowledge as possible."
Other scheduled F1 rule changes will affect tires. For 2010, they will include a ban on tire warmers (blankets used to preheat the tires), which will make the new sensor particularly relevant as race engineers require trusted data to help achieve the best possible qualifying and race performance.