Michelin Shows Off eTire II

Five years after the debut of its original eTire Tyre Pressure Monitoring System (TPMS), Michelin has begun to show off its eTire II second-generation sensor equipment. This new eTire system incorporates technology devised by UK company Transense Technologies, who granted Honeywell a licence to develop their TPMS design on behalf of the French tyre maker.

The eTire II system relies upon a sensor patch placed inside the tyre’s sidewall. This sensor weighs only 11 grams (less than half an ounce) and contains no batteries or wires, making it virtually maintenance free. The sensor utilises the principles of Surface Acoustic Wave (SAW) technology as developed by Transense, and works by sending an acoustic wave through the tyre.

This acoustic wave is used to monitor tyre pressure and temperature many times each second, and can detect if any deviations from the manufacturer’s recommendations occur. Specifically, it can accurately measure pressure, compensating for temperature. This temperature compensation allows the eTire II system to identify tyres with slow leaks that may otherwise be concealed by the tyre’s higher temperature and not become apparent until the tyre cools, which means that arriving at your vehicle in the morning to find a flat tyre waiting for you will hopefully become a thing of the past. In addition, it has been estimated that fitting a SAW system such as eTire II to a vehicle can improve its fuel efficiency by ten per cent.

The sensor works in conjunction with a series of readers, either hand held, fixed or internet-based. The hand held reader is a more ergonomic design than that of the previous eTire system, and, like the drive-by reader, obtains information from the sensor patch via radio frequency. The internet-based tracking software, known as BibTrack™, identifies each individual tyre through a unique ID number given to each sensor patch. Every time a tyre is scanned by a hand held or a drive-by reader, tyre pressure, temperature and any recommended user actions are automatically updated and ready for viewing on the BibTrack™ website. This feature allows fleet operators to monitor each vehicle’s tyres from any computer with internet access.

Transense signed a licence agreement with Michelin in 2001 to work exclusively with their engineers to develop a TMPS system. In 2003 they also signed a deal with Honeywell to bring Transense’s SAW sensors into commercial production and to develop electronics that did not require battery power. This is a point of difference separating the eTire II system with those of competitors.

Using Transense’s licensed technology, the eTire II system has been developed by Michelin Americas Research and Development Center (M.A.R.C.) and Honeywell Sensing & Control under a joint development agreement. Initially available for use on truck tyres, this is the first time that Transense SAW technology has been put into volume production.