Design of a Double-Path Magnetic Circuit Structure Hybrid Fuel Injector Considering Demagnetization Characteristics

Abstract

This paper proposes the design and analysis of a double-path magnetic circuit structure for a high force density hybrid fuel injector. A micro-permanent magnet (PM) ring is inserted in the gasoline direct injector (GDI) to reduce the leakage flux and increase the force density of the system. In addition, the demagnetization characteristics of the GDI are analyzed according to the injector's working environment. The PM is used to evaluate the demagnetization for three categories of material: NdFeB PM (N42), ferrite PM (FB6N), and SmCo PM (SmCo26H). Comparisons of a hybrid GDI and basic GDI are made in terms of output force, efficiency, and response time as the main characteristics. In addition, the costs of PM materials are investigated.