Abstract
Keywords
Fuel Injector, Solenoid, Modelling, FEM.
Abstract
The aim of this research was to develop a specific modelling approach capable of reducing the size of the fuel injector solenoid while improving its response time and attraction force. Several modelling and simulation procedures have been developed involving various aspects of solenoid component modifications in order to formulate an evolution process for miniaturising an automotive fuel injector solenoid. Specific factors that were found to influence the optimum operation of the fuel injector solenoid include the geometrical shape of individual solenoid components, material properties, air-gap constraints, boundary conditions, current source conditions, mass constants, and damping coefficients of the plunger. The modelling of fuel injector solenoids has been done using the finite element method (FEM) software for electro-mechanical and electro-magnetic analysis, Maxwell 2D/3D and Electro-mechanical System Simulator (EMSS). Simulations showed that force distribution in the main air-gap was directly influenced by the taper angle of the plunger pole faces and the plunger length. The theory behind the permanent magnetism has prompted an alternative way to solenoid design for maximum attraction force. The precise definition of the electro-mechanical motion of the plunger was of key importance to reducing the fuel injector solenoid response time. Several features that influence the response time of the solenoid fuel injectors have been investigated in more detail and claim to be closely related to stroke and mass of the plunger, spring characteristics, motion and rebound of the plunger. Using the developed technique, the initial size of the fuel injector has been reduced by 35%, the attraction force increased by 26% and the response time reduced by 76%. The modelling and simulation procedures have been successful in reducing the response time that somehow seemed difficult to achieve through experiments alone, under given conditions. However, by frequently repeating the design and experimental trials, the minimum response time was achieved using the virtual rebound delay model. The simplicity and effectiveness of the developed methods, allowed for quick and accurate evaluation of the improved fuel injector solenoid design.