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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.

In order to approach the Carnot efficiency in modern diesel engines that see variable loads and high speeds, programmable electrically controlled fuel injections are required. Traditional solenoid based transducers are binary and cannot achieve this programmability while newer piezoelectric transducers are susceptible to performance degradation due to high pressures and temperatures. This paper presents the experimental characterization of a programmable diesel fuel injector transducer designed by Great Plains Diesel Technologies, L.C. to address the limitations of existing technology. This transducer employs a little-known magnetostrictive alloy to position its needle. In contrast to piezoelectric ceramics, quantum mechanics endows this alloy with the indestructible property of magnetostriction, the ability to strain proportional to a magnetic field. This allows it to be fast and infinitely adjustable (or, “programmable”) without degradation.

Magnetostrictive and piezoceramic materials combine specific energy with speed, enabling fast and powerful but compact transducers. These materials, used in US Navy sonar for decades, elastically strain under the influence of a magnetic or electric field. Piezoceramics become active when electrically poled. Poling being artificial, the ceramic loses its piezoelectric properties under overstress, overstrain, overvoltage, or overheating, conditions present in a diesel engine that limit injector performance. In contrast, a magnetostrictive alloy of terbium, dysprosium, and iron will not permanently degrade under the same conditions, enabling an injector to be pushed to the highest possible speed. Quantum mechanics dictate that the non-bonding 4f electron cloud of the terbium atom be oblate, not spherical, an inherent property that connects magnetic and elastic influences.