A rapid engine prototyping methodology: Coupling engine geometry and flow field to engine performance prediction

In this dissertation, we propose a rapid engine prototyping methodology which can be an extremely valuable tool from preliminary engine design and optimization to control system development. Specifically, the proposed methodology links three preexisting tools: a water analog engine simulator with a 3-D particle tracking velocimetry technique, a thermodynamic, crank-angle resolved engine model, and a complete, low-frequency dynamic powertrain mean value model. The methodology comprises several steps, which can be used separately or in conjunction, as follows:; The first step involves using a water analog engine simulation rig coupled with an automated 3-D particle tracking velocimetry (3-D PTV) system. This allows to use an actual engine head or a rapid-prototype “soft” flow box to quickly determine the complex large-scale 3-D in-cylinder flow field during the intake stroke.; The second step involves extracting some relevant metrics from the 3-D PTV flow field results (mean flow and bulk turbulence characteristics) and linking these to subsequent heat release/burn rate characteristics.; The third step involves using the above combustion parameterization in a thermodynamic, crank-angle resolved single cylinder engine model to perform detailed engine simulations and obtain crank-angle resolved in-cylinder pressure and hence overall performance characteristics for various engine operating conditions.; The last step involves using these detailed simulation results to derive a calibrated mean value model which is then used in an engine/powertrain simulator for control system design and optimization. This step along with the previous steps in our procedure allows to perform a virtual engine mapping which leads to a calibrated mean value model and finally to control system development.; The joint use of all these tools represents a powerful and fast methodology for preliminary engine design and optimization, as well as calibration of existing engines. In the first case, it provides an opportunity to considerably reduce the design/optimization cycle time and cost, by decreasing the number of actual engine prototypes to be built. In the second case, it provides an opportunity for control system development early in the development cycle (potentially prior to an actual functioning engine prototype) and for the development of advanced model-based engine control strategies.