Continental In-Tire Sensors Read Tread Depth

AUBURN HILLS, MI -- The close collaboration between electronics and tire developers at Continental, the international automotive supplier, continues to be strong. This working partnership has enabled Continental to create tire pressure sensors that will be able to detect when a tire change is necessary due to insufficient tread depth. The tire tread provides the gripping action and traction that prevent a vehicle from slipping or sliding, especially when the road is wet or icy.

"The importance of tread depth awareness has been established in many countries by creating minimum tire tread depth requirements for safe driving. Currently, tires have a built-in tread wear indicator that requires manual monitoring. Continental has advanced this technology by embedding a sensor in each tire that conveniently identifies tread depth electronically, ultimately increasing awareness and safety by notifying the driver when a tire change is necessary," said Michael Crane, head of the Body & Security business unit Continental, North America.

Intelligent software makes the new feature possible. The software determines tread depth from gradual changes in tire rolling characteristics. The in-tire pressure sensor infers running characteristics from the variations in tire deformation. The new feature is slated to be available in new 2017 vehicle models equipped with direct tire pressure monitoring systems (TPMS) from Continental (electronic Tire Information System, eTIS).

The technology behind tread depth detection

For this new type of electronic tread depth detection, Continental engineers draw on a tire's gradually changing rolling characteristics over a longer period of time. Tire and electronics developers conducted an intensive series of tests that allowed the basic data to be fed into the electronics of future vehicles. The specifics of the tires' altered rolling characteristics are compared with the accumulated data. If the tread is run down to below a tire-specific threshold value, the on-board electrical system will signal that a tire change is due. Additionally, if preferred by the driver, the vehicle's telematics module is capable of informing the driver's local dealership or auto service center of the needed tire change. Even with this added feature, a driver is still able to check for themselves when the recommended or legally required minimum tread depth has been reached. For this purpose, the tire has wet-TWI (tread wear indicators). These are small ridges between the tread grooves that indicate that the brand manufacturers' recommended minimum tread depth (3 millimeters in summer tires, 4 mm for winter tires) has been reached.

Tires becoming intelligent

With the introduction of the first tire pressure sensors from Continental in 2002, the most important link between the vehicle and the road became intelligent. Since then, tire pressure sensors have been able to provide tire-by-tire information about the current tire pressure and conveniently warn drivers if the pressure is too low. Tire sensors can help ensure optimum inflation pressure; this extends the life of a tire, reduces fuel consumption and lowers CO2 emissions. Continental relies on these direct measuring systems with precise pressure display. With these, a sensor reads the tire pressure either at the valve or directly under the tire tread. If a second set of tires needs to be equipped with sensors, Continental already supplies the corresponding retrofit sensors under the VDO brand.

Continental extending the operational scope of future tire sensors

Continental is working with automakers all over the world to further expand the range of features that in-tire pressure sensors can provide. Every tire loses air slowly. The tire pressure sensor ensures that drivers are informed of tire pressure loss at an early stage. Therefore, they do not run the risk of driving with one or more dangerously underinflated tires. Initial car models equipped with intelligent sensors from Continental automatically signal when a tire being inflated has attained the required tire pressure. The Filling Assistant, which specifies the exact inflation pressure of each tire on a smartphone, is helpful when inflating tires and guarantees the right tire pressure even when non-calibrated filling stations are used. A brief honk and blink signal can be given to confirm when the tire has been inflated to the correct pressure level. As a result, rolling resistance is reduced and the tires perform at their maximum capability in terms of safety, economy and comfort.

Load detection gearing up for series production

Another feature soon to be introduced is load detection. Here, the vehicle uses software developed by Continental to detect specifically whether the maximum permissible load has been exceeded. This is a useful feature when hauling large loads or towing a trailer. The electronics quickly detect a change in rolling characteristics due to excessive load and inform the driver of the respective axle load. Future driver assistance systems will use the load information to adjust their functions to the respective vehicle load. Over the long term, this will enable safer and more convenient automated driving features.

With sales of around €33.3 billion in 2013, Continental is among the leading automotive suppliers worldwide. As a supplier of brake systems, systems and components for powertrains and chassis, instrumentation, infotainment solutions, vehicle electronics, tires and technical elastomers, Continental contributes to enhanced driving safety and global climate protection. Continental is also an expert partner in networked automobile communication. Continental currently has approximately 182,000 employees in 49 countries.

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