In what could be a breakthrough on both environmental and economic fronts, a group of Purdue University students have modified an industrial lawn mower to use a water-powered hydraulic system instead of one that uses petroleum-based fluid. All of the mower's hydraulic systems - including power steering, power brakes and transmission - have been successfully switched to operate on water the University announced.
Although the project was undertaken to show it could be done, a mower with this type of hydraulic system does have a purpose. Lawn mowers of this type are used on golf courses and can leak some hydraulic fluid on the greens. Hydraulic fluid kills grass, which is troublesome when the costs for construction and maintenance of some greens can run into the tens of thousands of dollars.
The Purdue student researchers and Gary Krutz, professor of agricultural and biological engineering and the students' advisor, note that water-powered hydraulic systems could come in handy for a wide range of vehicles that use high-pressure systems, such as heavy equipment used in construction, agriculture, forestry and mining. Autos generally would not benefit from such a system because hydraulic brake and steering systems are not pressurized to a high extent.
Although the engineering and parts required for a water hydraulic system cost more right now, the researchers say that is only because such a system is totally new and no manufacturers are mass producing them. Therefore, the parts are not readily available and all the applications for water hydraulics are not evident. Such parts include those made from ceramic, stainless steel or fiber because of the need for tight manufacturing specifications and the corrosion factor when dealing with water.
"If all of the research and development were done, all of the major companies would be using water instead of hydraulic fluid," Krutz said. "Because the industry is in its infancy, mass production hasn't lowered the cost."
Besides the benefits of avoiding problems with leaking hydraulic fuel when water is substituted, the researchers note that using water increases the energy efficiency of a vehicle's system because it flows better than hydraulic fluid. By using water, the efficiency is increased about 10 percent and while that might not seem so much, Krutz points out this efficiency boost translates into about 500 million gallons of fuel per year. In addition, he expects that the lower friction in the water system would mean less wear for equipment.
"All we need is for one major lawn mower company to decide to use this technology in a premium machine, and the cost would drop significantly," says Krutz.