Control Law for Fast, Non-Ringing Transients for Direct Injector Needle Actuators and Other Dynamic Systems

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Control Law for Fast, Non-Ringing Transients for Direct Injector Needle Actuators and Other Dynamic Systems

Bright, Charles B.

This paper discloses the simultaneous and interdependent development of an actuator and its novel control law. Magnetostrictive alloy terfenol-d offers high energy density. When packaged properly, quantum mechanics within terfenol-d maintains its performance. The novel control law tames and directs its untapped potential. Therefore, terfenol-d can provide lifetime direct operation of the needle in an injector for a compression-ignition engine, potentially improving emissions, efficiency, fuel flexibility, and combustion noise.The novel control law yields a custom forcing function for desired boundary conditions such as either non-ringing or deliberately ringing transients for this actuator as well as other non-magnetostrictive dynamic systems. The two key characteristics that enable such a custom forcing function are to (1) use the Bright Principle of modeling all energy terms and (2) setting up a specific polynomial to solve for the desired boundary conditions for a particular dynamic system.Test data from an actuator aided the development of this general and flexible control law. Implementing the control law, a computer predicts the necessary voltage with respect to time to achieve a set displacement within a defined transient time. A difference in frequency content appears between fast Fourier transform (FFT) spectra of non-ringing followed by deliberately ringing displacement data.