Energy return wheel
The Energy Return Wheel (ERW) is an airless tire designed by Brian A. Russell. The ERW is registered under the company name "Britek Tire and Rubber", with the aim that their product will be used primarily in automobile and truck markets.
The first patent was applied for in 2002, the same year Britek was founded, in the United States of America. Since then there have been several more applications in the domestic market and internationally, including China.
Structure and Function
The ERW is constructed of two major parts, the inner rim & structure that mounts on a standard pneumatic wheel vehicle axle, and the outer rim that has a rubber membrane on the inner side with a tread on the outer side.
The construction requires connection between the inner and outer, this was originally by coiled spring and has now been replaced by stretched rubber, the manufacturer claims this gives the elastic feature for which the product is named, it is not clear if this translates to improved efficiency or if the increased environmental cost of manufacture outweighs this. Due to the nature of these tyres, replacement is likely to be prohibitively expensive and difficult compared to a standard pneumatic tyre.
The innovator, Brian A. Russell, claims the following, it is however unsubstantiated and scientifically inaccurate:
An object that is sprung requires dramatically less energy to move than an unsprung object. In addition to the use of springs, an object can be sprung by stretching rubber. Scientists call this “Elastic Potential Energy.” At the center of the ERW is a layer of rubber. Through the use of adjustable rods, the rubber is stretched, which stores elastic potential energy in the wheel, turning the ERW into a 360-degree slingshot that retains energy (hence the term “Energy Return Wheel”). When the ERW is attached to an object, that object becomes sprung. The attached object becomes de-weighted and requires dramatically less energy to move than an unsprung object. Less energy to move means an increase in fuel efficiency.
In theory, when a car is riding on ERWs, it will be like riding on 4 slingshots. This “Slingshot Effect” could cause a dramatic improvement in the car’s acceleration. Because the ERWs could de-weight the car, its braking performance should also be improved. Because the ERW doesn’t have a sidewall like pneumatic tires, there shouldn’t be any lateral sidewall deflection when the car is cornering. No sidewall deflection means an increase in handling performance as well.
Corporate stance and goal
Britek claims ERW improves fuel efficiency and increases performance by reducing the amount of energy lost through tire deformation, this does however reduce grip as less rubber is in contact with the road at any given point.
Britek markets their product as follows:
To dramatically reduce our dependency on foreign oil, in addition to upgrading new vehicles, we need a technology that can be put on vehicles that are already on the road! The great thing about the ERW is that it can replace a vehicle’s wheel and tire. This means the ERW can be put on any vehicle, whether it is new, used, car or truck. The ERW is not a competitor to hybrid, electric, hydrogen, ethanol, biodiesel and other fuel saving technologies. Quite the contrary, because it will only make vehicles using these technologies more efficient.
- Company information
- Registered Patents: US6701985, US7104297, US20100013293 on Google patents
- Patent 03817173 (in Chinese)
- First prototype, 2008 and rolling resistance test, showing improved rolling resistance against a standard pneumatic tire.
- Second prototype, 2010
- Cycling: road and off-road applications