Modeling of Diesel Combustion and NO Emissions Based on a Modified Eddy Dissipation Concept

Modeling of Diesel Combustion and NO Emissions Based on a Modified Eddy Dissipation Concept

Journal & Paper No:

SAE 2004-01-0107

Authors:

Sangjin Hong, Dennis N. Assanis, Margaret S. Wooldridge, Hong G. Im
The University of Michigan
Eric Kurtz, Ford Motor Company
Heinz Pitsch, Stanford University

Abstract:

This paper reports the development of an improved model of diesel combustion and NO emissions, based on a modified eddy dissipation concept (EDC), and its implementation into the KIVA-3V multi-dimensional simulation. Compared to the commonly used eddy break-up (EBU) model, the EDC model allows more realistic representation of the thin sub-grid scale reaction zone as well as the small-scale molecular mixing processes, thereby achieving higher fidelity of the simulation. Realistic chemical kinetic mechanisms for nheptane combustion and NOx formation processes are fully incorporated. In addition, a transition model based on the normalized fuel mass fraction is successfully implemented to reproduce ignition and combustion processes accurately. Simulations are performed for various engine speeds, injection timings, and EGR content, and the results for the basic engine performance agree well with the experimental data. The predictions for NO concentration also show a consistent trend with experiments, demonstrating the improved predictive capability of the present model for diesel engine design and development.

Paper: P2004_01.PDF