Mower uses water hydraulics

Gary Kurtz estimates that using water instead of petroleum fluids in hydraulic systems could save 500 million gallons of gasoline in the U.S. alone. Saving fuel is one reason the professor of agricultural engineering and his students at Purdue University built a lawn mower that is propelled and steered with a water hydraulics system.

They are demonstrating that water's lower viscosity boosts the mower's energy efficiency. They also hope to show that the technology may be practical for agricultural, construction, mining, and forestry equipment.

Viscosity is a measure of how fast liquids flow. Water's lower viscosity means less energy is required for pushing it through the hydraulic system. Kurtz estimates that the cost of building a water hydraulic system for his mower is approximately twice that of a comparable petroleum-based system. However, Kurtz points out that the cost of stainless steels and ceramics needed for producing water hydraulic systems are dropping, which would help make water hydraulic more affordable.

"We have a proposal in to a golf course association now," says Kurtz. "They like the idea because oil now leaked from the hydraulic systems in lawnmowers kills the grass on golf course greens." Danfoss, Fairchild Manufacturing, Indianapolis Valve and Fitting, Parker-Hannifin, and Swagelok provide equipment for the project. Jacobson, a division of Textron, donated the mower retrofitted with the water hydraulic system.

For more information e-mail Kurtz at [email protected].