Modeling

The unique geometry of the Legacy engine introduces thermodynamic processes that are not well understood. This is due to the manner in which the working volume changes as a function of the rotation of the engine; it is an unavoidable three-dimensional problem as illustrated below.

Additionally, the divided combustion chamber that exists at the time of combustion and the interaction between the combustion pocket, shown in the adjacent figure, in the Roton and the injector nozzle require fundamental characterization to fully exploit the potential of the Legacy engine. Models of conventional engines have been developed which allow engineers and designers to obtain fundamental understanding of the combustion processes in these engines. These models are not readily applied to the unique geometry of the Legacy engine; a model must be developed based on, but quite different, than conventional engine models.

To address the challenge of optimizing the unique combustion process and engine geometry, an engine model capable of simulating the operation of the engine will be developed. The model will be an integrated model consisting of commercially available FEA software for fluid dynamics associated with gas exchange and heat transfer within the cooling and lubrication system, coupled with proprietary custom-developed combustion and chemical kinetics analysis software. The combustion modeling software currently consists of a multi-zone phenomenological model of combustion and ionization in a Direct Injection Diesel Engine (DIDE).   Fresh mixture regions, injected fuel, flame and post flame regions are simulated by Unsteady Well-Stirred Reactors (UESR) with application of detailed chemical kinetics to the simulation of the chemical interaction of the operating medium. Any in-cylinder parameters of interest can be predicted, and any effect of these parameters on the operational performance of the engine can be evaluated. Theoretical study and comparison with experimental data demonstrate the reliability of the theoretical results, dependability of the model, and ability to provide deep parametrical analysis to improve operational performances of DIDE. Examples of comparison of model predictions to experimental data are shown below.

The combustion and chemical kinetics simulation software exists for conventional diesel engine configurations, and it will be modified and enhanced for the unique geometry of the Legacy Engine.

The model will be calibrated, based on empirical data obtained from dynamometer evaluation of the prototypes, throughout the development phases of the project.