Purdue's Fuel-saving Designs Improve Hydraulic Systems

Researchers at Purdue University in West Lafayette, Ind., have shown how to reduce fuel consumption and dramatically improve the efficiency of hydraulic pumps and motors in heavy construction equipment, according to a Sept. 9 press release.

The new designs incorporate two innovations: They eliminate valves now needed to direct the flow of hydraulic fluid in heavy equipment, and they also might incorporate textured "microstructured" surfaces inside pumps to improve performance.

Research has shown the "valveless" design alone could reduce fuel consumption by 40 percent. Further savings could be realized by combining the valveless design with the advanced microstructured surface concept, said Monika Ivantysynova, Maha Fluid Power Systems Professor in Purdue's School of Mechanical Engineering.

The microstructured surfaces have been shown to dramatically reduce power losses due to friction caused by hydraulic fluid, said Ivantysynova, director of Purdue's Maha Fluid Power Research Center.

Findings were detailed in several technical papers presented by her research group earlier this summer at the Fifth Fluid Power Net International Ph.D. Symposium in Krakow, Poland.

"Currently, the best pumps and motors may have a top efficiency of 92 percent, but this efficiency level is only in a certain range of operation," Ivantysynova said. "These hydraulic pumps don't always run at this maximum level. Sometimes you only need them to provide a small amount of pressure or flow, for example, to simply hold a tool in place. Then you aren't running the pump under its highest loads, and the efficiency goes way down."

Hydraulic systems use a central "variable displacement pump" that pressurizes fluid, and valves direct the flow of fluid to "actuators," which move tools such as shovels and buckets in excavation equipment. In the new valveless design, each actuator has its own pump, eliminating the need for valves.

Purdue has filed a patent for the innovation, called an "advanced gap surface design."

The innovations might be applied to a new "hydraulic hybrid" concept for cars that would use a hydraulic motor to save energy in hybrid cars.

The Maha Fluid Power Research Center is part of the Engineering Research Center for Compact and Efficient Fluid Power, funded by the National Science Foundation, participating companies and universities.

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