ORNL Simple Global LNT Model

Stuart  Daw, Oak Ridge National Laboratory

Category: Models and Mechanisms
Technology: LNT (Lean NOx Trap)


The information below and in the attached MatLab program files are made available through the Crosscut Lean Exhaust Emissions Reduction Simulation (CLEERS) website as supplemental supporting documentation concerning previously published research results from the Fuels, Engines, and Emissions Research Group at the Oak Ridge National Laboratory. Funding for this research was provided by the U.S. Department of Energy Office of Freedom Car and Vehicle Technologies under the Energy Efficiency and Renewable Energy Program. The associated files are intended for research and discussion purposes only and are not warrantied for any other purpose, express or implied.

In posting this collection of computer codes, our objective is to provide an example set of computational tools that potentially could be useful for evaluating and summarizing observed trends in laboratory bench reactor characterization measurements of lean NOx trap (LNT) materials. UNDER NO CIRCUMSTANCES ARE THESE CODES INTENDED FOR FULL LNT SYSTEM SIMULATIONS OR SYSTEM DESIGN! For this reason, there are a considerable number of simplifying assumptions that are made, and these assumptions are documented in the accompanying files that can be downloaded from the CLEERS website. It is our intention to post improvements to these codes from time to time as they become available, and any updates will be documented as update and/or version information at the beginning of each function file. Future improvments that are currently planned include graphical user interfaces for defining input conditions and parameters and displaying results, as well as improvement in the physical assumptions made.

The code files are structured to run in a linked fashion to simulate the time and spatial species and temperature variations in an LNT monolith during a defined sequence of capture and regeneration cycles. To function properly, all of the associated function files should be located in the same directory. In addition to defining the cycle conditions, it is necessary for the user to specify initial conditions, flow and geometric parameters for the monolith, and isotherm and kinetic rate coefficients. Example default values are provided in the current files, but these should be adjusted by the user to conform to their specific conditions and LNT material properties.

Any questions regarding the technical details of the model or LNT behavior should be directed to Kalyana Chakravarthy at ORNL (chakravartvk@ornl.gov).

Readme File: ORNL_Simple_LNT_Model_Readme.pdf

Data Files:

Submission Date: 2004-09-30