<div class="htmlview paragraph">Developing dynamic models of internal combustion engines can be very challenging because of the broad range of components that comprise the engine, as well as the range of engineering disciplines that are brought to bear in the design. The task is further complicated because the goals of such a model can vary immensely depending upon its use, and in a high-quality dynamic model these goals will drive the overall structure and fidelity of the model. Note that the quality or usefulness of the dynamic model is independent of its fidelity.</div> <div class="htmlview paragraph">This paper presents a generalized modular engine modeling structure, developed using MathWorks' MATLAB/Simulink software, which can be used in developing dynamic models of internal combustion engines or other dynamic powertrain models. The generalized block is discussed in detail, and specific applications of this block are shown within an overall engine model. A discussion of how this approach addresses the typical causality issues that arise when modeling dynamic systems is included in the paper. Finally, validated simulation examples are presented for a specific engine, and examples of simulation speed are also included. Using the generalized block greatly simplifies the overall structure of the model, and allows users to modify the model with few concerns regarding introducing causal problems as these modifications are made. This flexibility is important so that users can experiment with new concepts or explore the effects of powertrain modifications.</div>