Simulation studies on the boot shape injection of a giant magnetostrictive injector

Giant magnetostrictive injector using giant magnetostrictive material acting an electronic controlled injector may be one new promising injector to acquire adjustable injection rates while maintaining large injection quantity. An electronic controlled injector driven by a giant magnetostrictive actuator was designed through combining the driving requirement and output characteristics of the material. To promote responding speed of the coil current, the driving voltage with open-hold-fall type waveform was employed just like using in an electromagnetic injector. Simulation model for the injection characteristic of the injector was established using AMEsim software and verified using experimental results collected by the single injection meter. From simulation and experimental results, designed giant magnetostrictive injector showed good performances as maximum spray rate of 4.5 L/min and minimum spray pulse width of 0.21 ms, and realized the boot shape injection when generated by the designed voltage wave. Furthermore, duration time and amplitude of the pilot spray part in a boot shape injection were respectively adjusted through changing the dwell time and opening time. The boot shape injection reached by the giant magnetostrictive injector can reach quite accurate control of fuel injection and then promote fuel efficiency effectively.

Proof of Principle of a Fuel Injector Based on a Magnetostrictive Actuator

One of the goals of modern internal combustion engines is the NOx-soot trade-off, and this would be better achieved by a better control of the fuel injection. Moreover, this feature can be also useful for high-performance hydraulic systems. Actual fuel injection technology either allows only the control of the injection time or it is based on very complex mechanical-hydraulic systems, as in the case of piezo-actuators. This work describes the basic steps that brought the authors to the realization of a concept fuel injector based on a Terfenol-D magnetostrictive actuator that could overcome the previous issues, being both simple and controllable. The study provides the design, development, and a feasibility analysis of a magnetostrictive actuator for fuel injection, by providing a basic magneto-static analysis of the actuator, the adaptation of a suitable standard fuel injector, and its experimental testing in a lab environment, with different shapes and amplitude of the reference signal to follow.

Temperature compensation design and experiment for a giant magnetostrictive actuator

Because the performance of giant magnetostrictive materials (GMMs) can vary at different temperatures, the positioning accuracy of a giant magnetostrictive actuator is affected by heat. In this work, a new simplified control strategy under compulsory water cooling is proposed to maintain a constant GMM temperature. Based on this strategy, a coupled turbulent flow field and temperature field finite element model is created for a GMM smart component. The model is simulated using COMSOL Multiphysics software version 5.3. Through simulations, the temperature field distribution of GMM smart components is analysed under different drive input currents and cooling water flow rates. Based on the obtained simulation results, a GMM intelligent component temperature control device is constructed. The experimental results are in good agreement with the simulation results; a thermostatic control effect is achieved in the thermostat of the giant magnetostrictive rod. Thus, the proposed temperature control strategy is proven effective via simulations and experiments.