Researchers at Purdue University have shown how to reduce fuel consumption while improving the efficiency of hydraulic steering systems in heavy construction equipment. The new approach incorporates several innovations: It eliminates valves now needed to direct the flow of hydraulic fluid in steering systems and uses advanced algorithms and models to precisely control hydraulic pumps. New designs might also incorporate textured "microstructured" surfaces inside pumps to improve performance.
Typical hydraulic systems in heavy equipment use a central "variable displacement pump" that delivers fluid, and valves that throttle the flow of fluid to linear and rotary "actuators" that move tools such as shovels, buckets and steering mechanisms. This throttling causes energy to be dissipated as heat and wasted.
In the new valveless design, each actuator has its own pump, eliminating the need for valves. The actuator motion can be precisely controlled by adjusting the pump displacement, which changes the amount of fluid being delivered to the actuator. Being able to adjust the pump displacement makes it possible to run the machinery's diesel engine at optimal speeds, resulting in additional fuel savings.
Testing the new electro-hydraulic power steering system on a front loader has shown a 15 percent fuel savings and 23 percent increased machine productivity, for a total fuel efficiency increase of 43 percent during steering maneuvers. The new steering system also may help reduce operator fatigue while improving safety by controlling the level of steering-wheel torque feedback.