NEW HAVEN, Conn.-Pirelli Group is developing an anti-deflation system for car tires called Integrated Modular Expanded Foam-EMI, for ``Espanso Modulare Integrato'' in Italian. EMI is a circular ring of butyl rubber foam inserted with special equipment inside an uninflated tire. As the tire is inflated, the air pressure compresses the EMI foam against the inside of the rim, reducing centrifugal mass and limiting the increase in wheel inertia, the company said.
If the tire loses air, the foam expands to fill the tire's internal space, supporting the carcass as if it were properly inflated.
Pirelli claims the foam keeps the tire performing at ``virtually optimum operating characteristics.'' A company spokesman declined to discuss what characteristics were negatively affected when the foam takes over for air.
Pirelli said EMI ``worked perfectly'' during its first public test in the recent Rally of Portugal, where driver Carlos Sainz finished eight miles of the race unaware his Pirelli-shod Subaru Impreza had suffered a puncture in the left front tire.
A Pirelli spokesman could not predict when, if ever, the technology would be available to the aftermarket, although designers are currently creating an EMI version for slick racing tires. Among the obstacles designers are facing with EMI, he said, is how to make drivers aware they have suffered a flat so the tire can be inspected for potentially dangerous structural damage.