Abstract
KEYWORDS:
diesel engine, injection system, injection pressure, finite element method
ABSTRACT
The paper presents the analyses of the behavior of the diesel engine injection system elements, using the finite element method, for appreciation of their influences on the injection process and for improving it. A continuous structure has an infinite number of free degrees, so that an analysis in static or dynamic regime involves a high number of simplifying hypothesis, according to the method that is used. Analysis with FEM allows tackling the structure without these simplifying methods. After the analysis of the injection system elements of a diesel engine with FEM, we can conclude the followings: · the own modes frequencies of the majority components of the injection system are overlapping with the fluid frequencies only in the high frequencies and low amplitudes zone (without the outlet valve spring and injection pipe); · overlapping of the oscillation frequencies of the outlet valve spring and injection pipe with the fluid frequencies in the fundamental frequencies zone, characterized by high amplitudes could induce the resonance phenomenon; · the fluid velocities in some sections of the injection pipe are very different, due to the waves which are algebraic totalized and are in different phases in these sections; · all these simulations, based on the finite element method determinate opportunities for a complex analysis, in connection with the reciprocals influences between mechanical elements with working fluid; · the simulation of the mechanical elements by FEM is extremely useful as a starting point for the experimental analysis.