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A fuel delivery system hydraulic model has been developed by coupling a distributed hydraulic network model with lumped models for the various components of the fuel system like the injectors, regulators, accumulators, etc. The resulting governing equations are linearized around the nominal system pressure and integrated using a fourth order Runge-Kutta algorithm with a variable time-stepping scheme. The model assumes isothermal behavior, negligible frictional losses and single-phase flow. The goal of the model is to study small signal type perturbations around the operating system pressure. Typical outputs from exercising the model are presented. The model can be used to study fuel pressure and velocity transients throughout the system and to design the various fuel system components in a system context.

This paper presents a numerical approach to evaluate the optimum rib configuration in a catalytic converter shell in order to ensure the safest stress state in a cellular ceramic monolith under assembly conditions. Specifically, the paper seeks to determine the rib width and orientation. Numerical studies are conducted on an axisymmetric, orthotropic, finite element model of a ceramic monolith to simulate the stresses under converter assembly conditions. Different rib widths and orientations are modeled. The ceramic monolith is modeled as a homogeneous continuum. The macroscopic stress state is transformed into stresses in the cell walls. The microscopic stresses are then compared to the base material strengths in order to determine monolith integrity.