Engine controller for the hydrocarbon reduction during cold start in SI engine

Abstract

A topology optimization approach considering the static and dynamic behaviors of rubber is proposed for the shape design of rubber in the vibration isolators. Many vibration isolators are made of rubber and they are operating under small oscillatory load due to structural vibration superimposed on the large static deformation caused by the self-weight of target structure. For the efficient design of vibration isolators, the precise analysis of the static and dynamic behaviors of isolation rubber is essentially necessary. Firstly the large static deformations of rubber with the incompressibility under very slow loads can be generally treated with the well-known hyperelastic constitutive equations and the mixed finite element methods with Lagrangian formulations for nonlinear analysis. The dynamic behaviors of the rubber in the vibration isolators under very fast and small oscillatory loads can be analyzed by the steady state viscoelastic constitutive model that is suggested by Kim and Youn and can precisely describe the influence of the large static deformations on the time effects of viscoelastic relaxation function. The topology optimization approach is selected as the design optimization technique in order to obtain the adequate shapes of isolation rubber. The main object of the vibration isolators is the reduction of the vibrations and forces transmitted from target structures. Also the vibration isolators must have large enough static stiffness in order to stably support the target structure. The topology optimization approach considering both the high structural stability and low vibration transmissibility of the isolators is proposed. The objective functions and design constraints are formulated with the performance measures of both the static and dynamic mean compliance to represent the performance of the structures. The continuum-based design sensitivity analysis methods are formulated and actually applied to determine the effective directions of design...