Optimization and simulation of a voice coil motor for fuel injectors of two-stroke aviation piston engine

Abstract

Two-stroke engines taking advantages of high power density and light weight as well as small size are widely used on aircrafts. Compared with conventional fuel injection system, gasoline direct injection technology can control the air-fuel ratio according to different working conditions and thus a more efficient combustion can be achieved. Normally, a solenoid valve is employed in the gasoline fuel injectors to control the injected fuel amount and timing. In this study, the performance of a novel voice coil motor for gasoline direct injection injectors of a two-stroke aviation engine is studied. The voice coil motor works as a linear actuator to pressurize the fuel, and thus the amount of injected fuel and the injection timing can be controlled by the driving current of the coil. As a result, the high-pressure pump of the conventional fuel injection system can be canceled. The working principle of the voice coil motor is described at first. Then, a finite element model of the voice coil motor is setup, and the influences of structure parameters including the coil turns, the magnetizer height, and the yoke thickness are analyzed. Subsequently, the magnetic equivalent circuit methodology is used to study the response characteristics of the voice coil motor. The results show that the coil turns, the magnetizer height, and the yoke thickness are three important parameters that will influence the electromagnetic force. The total mass and resistance of the coil and the coefficients k and k e are four important parameters that will influence the dynamic response time. A theoretical optimization of these parameters can improve the system performance of the voice coil motor significantly. The results of this study can provide a reference for the design of gasoline direct injection system for aviation piston engines.