Introduction

Purpose

The Engine Dynamics Library (EDL) bring mean value engine simulation to Modelica. The library is designed for modeling of the complete gas exchange and makes it easy to evaluate different super charging configurations and controller design. Transinet response of the exhaust gas conditions is captured, quickly defining boundary conditions for exhaust aftertreatment systems in different drive cycles.

Modeling and simulation

Many simulation tools are essentially user-interfaces for setting the parameters of fixed simulation models. This means that the actual equations that describe the model are impossible, or difficult, to modify by users. This Modelon modelica library offers a different approach and provides much more flexibility. In combination with a simulation tool this Modelon library is a complete modeling and simulation tool. This is important to understand, since it implies that the working procedure is slightly different and contains some additional steps

• Build models that describe the phenomena of interest,
• Tune the model parameters,
• Use the models to set up an experiment that exposes the phenomena of interest,
• Simulate the experiment, and
• Analyze the results.

This Modelon library contains a large set of pre-defined models and templates that makes most modeling tasks straightforward. For many standard tasks it is possible to use the library in the same way as a pure simulation tool, i.e. it is sufficient to choose the right model, define all parameters and start the simulation.

Flexibility with prudence

It is possible for users to modify and extend most of the models in the library, and also to complement the library with custom models. It is also possible to mix with model components from other libraries. This is one of the major benefits of describing models using a high-level modeling language like Modelica. Customization of models and components can be done either from the graphical user interface and diagram view, or, for advanced users, by typing Modelica source code. There is also great flexibility in setting up experiments and analyzing results. The flexibility implies great freedom for users to define models and experiments, but may also require more attention to details and understanding.

Library structure

The library is divided into a number of sub-packages for different types. In each package, components are readily available for use in system models. In addition to the component packages is an Experiments, which contains a number of system models that can be simulated. These models provides an idea of how to use the component models in the library.

In the top level of the library is the Media package, which contain definitions of medium property models. User can using the templates to define their own medium models. In the Utilities package supporting classes are maintained and these should not normally be used by the library user.

Modelon libraries

All Modelon libraries are compatible and can be combined to solve specific engineering tasks. Libraries that may be of particular interest for users of the Engine Dynamics Library are the Heat Exchanger Library, the Vapor Cycle Library and the Liquid Cooling Library.