Ph.D. Proposal Presentation by Thomas L. Wilson, Jr.
Tuesday, September 14, 2004

(Dr. Ben T. Zinn, Chair)

"A Novel Fast Actuator for Diesel Injection"


Previous diesel engine research has shown that pulse shaping is beneficial in reducing noise and emissions of soot and NOx from diesel engines. However, the range of pulse shapes that can be produced is limited by the frequency response of the injector. Thus, the key element to advancing pulse-shaping research in diesel engines is to develop a much faster valve actuator that can produce a greater range of pulse shapes.

The novel concept for the actuator is a device in which multiple coils are arranged axially along a magnetostrictive rod to control the extension of the device. The individually controlled coils can produce a spatial gradient in the magnetostrictive forces acting on the rod. The main hypothesis is that the spatial gradient allows dynamic properties of the mechanical system to be effectively altered through feedback control. The research consists of the design of a prototype actuator and valve assembly, the development of suitable model-based control algorithms to realize the increased speed of the device, and various tests of the actuator alone and actuator plus valve to demonstrate and verify the anticipated improvement in performance. Preliminary results, both in simulation and experimental tests, have shown that optimum feedback control of the system achieves a faster response than open loop control.