Simultaneous Consideration of Process Development and Die Design for Cold Forming a Fuel Injector Nozzle

Abstract

Higher strength and tighter dimensional tolerance is desired for the injector nozzles to attain high injection pressures for lower NOx and particulate emissions. Cold forming is an alternate method which can provide these characteristics replacing the present machining operation. Upset tests were carried out to study the flow stress properties for selecting a suitable material for this part. A knowledge-based system was used to design the die angles and a multi-stage cold forming sequence process to manufacture the injector nozzle. Finite Element Modeling was used to do the punch design and to optimize the punch loads and punch pressures for each stage of the forming process. Initial sequence design was modified based on the results of numerical modeling. The tooling was designed and experimentation was done to verify the formability and material flow.