Goodyear is building a new tire that can adjust its own air pressure as it rides down the road.
Searching for the air hose in the grimiest corner of a neighborhood service station may soon become a thing of the past. With the help of a $1.5 million Department of Energy grant, Goodyear is developing a tire that regulates its own air pressure. Though the company refused to leak details of how the system works, a 2009 patent application shows that the tire employs a pressurized internal tube with inlet and outlet valves. This differs from the automatic inflation system on military vehicles that use onboard compressors. "The Air Maintenance Technology system is powered by the tire itself as it rolls down the road," says Goodyear chief technical officer Jean-Claude Kihn. Underinflation can lead to tire failure and a possible crash, but in most cases it just wastes fuel. According to Goodyear, underinflation cuts a car's efficiency by 2.5 to 3.3 percent, which, at current fuel prices, effectively adds more than 10 cents per gallon.
Air entering the inlet fills a small, high-pressure tube encircling the rim.
2. Big Push
Air is forced through the inner tube by ground pressure on a low tire.
Tire pressure returns to normal as air fills it through the outlet valve.
Excess air escapes through the inlet port.
How It Works: Self-Inflating Tire - Popular Mechanics