http://www.caranddriver.com/features/10q3/continental_evolves_the_tire-pressure_sensor-tech_deptFederal regulations have required some sort of computerized tire-pressure monitoring system in new cars since the 2007 model year. Most of these are active types that employ a sensor mounted to each wheel, which in turn can relay pressures or warnings via the dashboard.
As both a maker of tires and electronic systems, Continental is taking a more integrated approach. It plans to mount the sensors to the inside of tires instead of the current practice of mounting them to the wheels.
By coupling the sensor to the tire and adding a bit of memory, the tire-pressure sensor (TPS) will be able to inform the car of specific info about the type of tire in use. For example, it would allow the car’s computer to adjust the top-speed governor to match the speed rating of the tires. This would eliminate the warning stickers placed on the speedometers of cars in Europe when snow tires with lesser speed ratings are fitted to fast cars. The system could also keep track of the location of each tire and when it was fitted, thereby fixing rotation intervals and tracking tire mileage and expected life.
There’s an accelerometer in every current TPS to detect wheel motion and allow the sensor to turn off, thus extending the life of its battery when the car isn’t moving. But when mounted on the inside of the tire tread, this accelerometer can also measure the length of the tire’s contact patch by detecting when the section of tread to which it is attached is in contact with the pavement. By knowing the length of the tire *contact patch, it could sense when a tire is heavily loaded and then warn the driver to raise the tire pressure.
This intelligent tire-pressure monitoring could also yield performance benefits. Porsche engineers have told us that the cold-tire pressures specified for 911s are too high for optimal lap times at the Nürburgring. They are set high to ensure tire durability on the off chance that an owner who lives a quarter-mile from the autobahn will peel out of his driveway and instantly go for top speed before the tires have warmed up and naturally increased their pressures. The Continental system could limit the car’s top speed until the tires achieve a safe temperature and pressure, thereby allowing lower cold-tire pressures for better handing.
Another trick on Continental’s blackboard is a feature to assist with setting tire pressures. The sensor, for example, could instruct the car to beep its horn or let the owner’s smartphone know when the correct pressure is achieved, thereby eliminating the need for a tire-pressure gauge.
For all of their benefits, these new tire-pressure sensors are purported to be less expensive than today’s wheel-mounted units. Additionally, with appropriate reprogramming, they could be moved from one tire to another since they simply snap into cups bonded to the rubber. Expect to see them around 2014.