Tire Refills ItselfTire Refills Itself

DETROIT, MI -- Engineers here at the SAE 2008 World Congress rolled out a new technology that would enable tires to re-inflate themselves.

The new technology, introduced at the event yesterday, requires no electronic controllers, pumps or motors.

Created by engineers at Coda Development in the Czech Republic, the system involves the use of a small cavity in the tire wall and an inexpensive “managing valve.” When a vehicle’s tires are rolling, the valve in the Self-Inflating Tire transfers air into the cavity, which in turn delivers it to the tire. The managing valve, which rotates along with the tire, refills on every revolution. Whenever the tire’s pressure is lower than the air pressure inside the tiny cavity, the system opens its intake and delivers air. When the pressure in the cavity and the tire are equalized, the system’s intake is disabled, and refilling ceases.

Coda Development engineers said the cavity is a fraction of an inch wide, and therefore delivers a very small amount of air to the tire when it’s needed.

“The volume of air doesn’t have to be big because the spinning of the tire is so frequent,” said Maros Topoli, partner and marketing director for the company.

Topoli said the system could be combined with an electronic tire pressure monitoring system, but added such technology isn’t necessary to make the system work.

The company’s engineers said under normal conditions, the Self-Inflating Tire’s intake is seldom needed. They estimate the intake is open only 1 percent -3 percent of the time.

The system, which won an Automotive Engineering Tech Award at the show here, has not yet been incorporated in any production vehicles.

“It should operate in any kind of vehicle,” Topoli said. “It could be a car, truck motorbike or bicycle. It doesn’t matter.”