Deriving energy from potholes
Jun 12 2014
The good news is that a new type of shock absorber has been built that converts the bumps and jolts of vehicles on rough roads into usable electricity. According to Anne Eisenberg, New York Times, usually, shock absorbers dissipate the energy of bouncing vehicles as heat. However, the shocks could now use the kinetic energy of bounces to generate watts, putting the electricity to use running the vehicle’s windshield wipers, fans, or dashboard lights.
According to Eisenberg, these modified shock absorber devices, called GenShocks, can be installed both in ordinary and hybrid vehicles, lowering fuel consumption by 1 to 6 per cent, depending on the vehicle and road conditions. The new shocks look like ordinary shock absorbers with an electrical power cord at one end. They plug into a power box that regulates the electricity they produce, putting it out at a voltage required by the truck, car or bus.
When a vehicle using the technology hits a small bump in the road, hydraulic fluid squirts into a turbine. The turbine then spins as fluid runs through it, powering a small electric generator. The system, which could someday help power hybrid cars, is controlled by electronics that ensure a much smoother ride than normal shocks while simultaneously generating electricity for the car to use.
In May 2010, the US national science foundation (NSF) awarded a small-business innovation research grant of $150,000 to Boston-based Levant, the producers of GenShocks, to test its shock absorbers with hybrid trucks. According to Juan E Figueroa, programme director, NSF, the economic impact of the new shock absorbers could be immediate if owners of truck fleets installed them. For example, driving in the city could save a tremendous amount of energy and fuel.
At present, GenShocks, the regenerative shock absorber is getting fitted to the next-generation Humvee of the US military. When installed on a 40-mile-per-gallon hybrid vehicle, the recovered energy can be used for fuel-efficiency gains between 3 per cent and 10 per cent. This saving is equivalent to up to a four-mile-per-gallon increase in fuel economy.
According to Karl Hedrick, a professor of mechanical engineering at the University of California, Berkeley, just as in the case of regenerative braking (a technique used by some hybrid vehicles to generate electricity from energy released when a car brakes), one could dump the extra energy in a battery instead of in the atmosphere. GenShocks will cost slightly more than conventional shock absorbers. However, one could get those dollars back through improved fuel economy.
According to Ted Bergman, NSF, much useful energy could be harvested on roadways. Bergman is administering a new programme, undertaken jointly with the department of energy, to research ways to harvest waste heat in vehicles and thus reduce reliance on foreign sources of oil. “75 per cent of the energy in vehicles with combustion engines is lost to waste heat,” Bergman says. “Instead of losing that energy, we want to convert some of it into kilowatts of electric power.”
GenShocks are among many innovations in a field known as energy “harvesting,” where, other researchers are also developing different types of energy-producing shock absorbers. For example, Lei Zuo, an assistant professor of mechanical engineering at Stony Brook University in Stony Brook, NY, has built different prototypes that generate electricity with electromagnets, producing potential fuel efficiency gains of 2 to 10 per cent.
The Stony Brooks team, recently designed the regenerative shock absorber (called the mechanical motion rectifier or MMR) using a hydraulic system that turns a set of rotational gears through the cars vibration. The gears, in turn, take the irregular vibrational energy and transfers it to an electrical generator that converts it to electricity, which leads back to the vehicles alternator. The electricity is then used to recharge the vehicles battery as well as its electronics, which provides between 2 to 8 per cent fuel efficiency over vehicles with standard shocks. This translates into a fuel savings of 4 per cent for vehicles that use an internal combustion engine and 8 per cent in savings for hybrid vehicles. Professor Zuo says that the MMR’s could also be applied to train tracks which would power electrical devices such as lights and crossing gates as the trains vibrational energy is transferred.
What’s the bottom line? Potholes are in plenty on Indian roads. Rather than spend energy complain about them, one could use these potholes to achieve greater on-road fuel-economy. If even 5 per cent of the 2,56,000,000 vehicles on the road today used these modified shocks, we could reclaim more power than Niagara Falls produces per year.
(The writer is on the faculty of Indian Institute of Technology, Mandi, India)