Goodyear recently announced it's new Air Maintenance Technology for large truck tires, a system which automatically adjusts tire pressures while the truck is in motion. The technology is stunningly simple in theory, and has now won multiple awards, including the Popular Mechanics 2012 Breakthrough Award. In this article we're going to take a look at this new technology and discuss why it works even when it seems like it really shouldn't.
Maintaining pressure is a big deal for any tire. Even in the absence of any reason for low pressure, such as nail punctures, air will still leak slowly out of the tire by osmosis, not to mention that temperature changes can have huge effects on air pressure. Low air pressure will cause a tire a number of major problems that are only magnified when dealing with large trucks and fleets of trucks, in fact fully 50% of all truck and tractor-trailer breakdowns involve tires. The most common problems caused by low air pressure are:
- Gas Mileage: Low pressures increase rolling resistance, and have a major effect on the car or truck's gas mileage. Studies suggest low air pressure currently accounts for a 2.5% to 3.5% drop in fuel economy.
- Wear Issues: Low pressure will cause the tire to experience irregular wear, such as cupping or scalloping in the tread blocks. This will inevitably shorten the life of the tire, in addition to usually making the ride pretty ugly.
- Damage and Blowouts: If air pressure drops below about 25%, the sidewall of the tire will begin to collapse and rub against itself, severely damaging the inner sidewall. This damage can very quickly lead to a blowout condition, which is tough enough to deal with in a car, but can be much tougher to deal with in a tractor-trailer.
Simple in concept, difficult in execution, Goodyear's Air Maintenance Technology consists of a tube running around the circumference of the tire, sandwiched in between the layers of rubber below the tread. This tube has an inflow valve on one end, open to the outside air, and an outflow valve on the other end which opens inside the tire. When a pressure sensor determines that the tire's pressure is low, the inflow valve is opened, allowing air to come into the tube. As the wheel turns, the weight of the truck compresses the tube, forcing the air through the tube and into the tire. This process is then repeated for every revolution of the tire until the pressure is back to normal, at which point the input valve is closed.
Sounds like the old problem of pulling oneself up by the bootstraps, doesn't it? It just doesn't seem like it should work to me, despite the fact that it seems to work just fine in actual practice. Hey, Popular Mechanics doesn't hand out awards to just anybody, you know. The key is in the weight of the truck, which squeezes the air in the tube forward much like squeezing a tube of toothpaste, compressing the air enough to force it into the tire even against existing pressure.
Goodyear debuted the technology last month at the Internationale Automobil-Ausstellung Commercial Vehicle Show in Hannover, Germany. The company plans to begin a large-scale fleet trial in 2013, with commercially available applications coming a year or two after that.