http://www.autoblog.com/2008/02/27/new-self-inflating-tire-constantly-under-pressure/
We all know that keeping your tires properly inflated will prolong their tread life, help you burn less fuel and increase your safety. But finding a working air hose when you're away from your garage is like trying to find a working clock in an early-80's Buick.
This is probably what led Coda Development, a Czech Republic company, to invent a new self-inflating tire. Sure, self-inflating tires aren't new, they've been around for years on commercial vehicles and even a few passenger vehicles . But most of those systems use compressed air to keep the tires inflated.
Coda's new system uses a peristaltic pump built into the tire to constantly maintain air pressure. You may have seen a peristaltic pump used in hospitals to deliver intravenous drugs to patients. It's basically a spinning wheel pressed against a liquid-filled tube. As the wheel turns, it pushes the tube's contents through one end and pulls more in the other. In our case, your car's wheel is the wheel and your air-filled tire the tube. A valve ensures that your tire's pressure is always constant. Theoretically, the peristaltic pump is much simpler and therefore more reliable than a compressor-based system. It's also potentially lighter, cheaper and doesn't require a power source. Sounds like a darn smart idea to us. Coda plans to display its system at the 2008 SAE World Congress in Detroit on April 14th through the 17th, so we'll see if it makes a splash there with auto industry engineers.
