Design of equivalent magnetic circuit and parameter analysis for improving performance of fuel injections

A fuel injector is a device which converts electric energy to linear motion energy without a separate mechanical link. Its structure is quiet simple, economical, and precise control is possible. Therefore, fuel injectors are widely used in automotive, consumer products and general industrial applications, such as switches, relays, and valves. However, there is a lack of in-depth studies devoted to fuel injector compared to its scope of use. Since general fuel injector applications are operated at high speed with vary short stroke, an in-depth study on improving the magnetic force performance is needed. This paper first presents a method of designing an equivalent magnetic circuit (EMC) for basic model which is a good compromise between simplicity and accuracy. Then due to significant leak flux and magnetic saturation in fuel injections models. We use the 2D finite-element method (2D FEM) to detail design and reduce the leakage flux from electromagnet pole to lead pipe which can improve the fuel injector performance. At last, analysis of axis asymmetry, 3D FEM, and experiments on prototype were conducted. As a result the optimal fuel injector with design sleeve in the lead pipe and cone type structures shows the substantially improved performance compared with a conventional design.