Thermal Transient Mono-Dimensional Fluid Dynamic Simulation on a High Performance SI engine for “Real-Time” applications

The present work has been developed in POWERTECH Engineering S.r.l., an important consulting firm in the field of the fluid dynamic simulation in collaboration with Alfa Romeo-Maserati (ARM). The reference engine is the V6 spark ignition engine already equipped on the Alfa Romeo Giulia Quadrifoglio. The present study is aimed to exploit the unquestionable advantages of the virtual simulation in terms of reliability of results and quickness of data gathering, for the representation of the thermal inertia and surface temperatures of the engine, as well as the heat rejected to coolant. Starting from the engine model provided with a 3D mesh for the evaluation of the thermal behaviour, instead of the simplified representation, the activity was firstly aimed to the calibration of the same thanks to the experimental data provided by the customer. A parallel activity of volumes reduction for real-time application and calibration of the hydraulic circuit has been performed. Then the engine model was made capable to do a thermal transient, and tested in its behaviour on a new thermal transient dataset referred to a warm-up procedure at constant engine working point. Then the integration between the two models has been done and the model obtained, produced baseline results to be used for the calibration of the thermal masses, introduced in the final step of the activity within the real-time hydraulic circuit model. The usefulness of such model lays in the fact that being a RT model it can be used in a driving simulator. Moreover, the model will be able to automatically calculate the heat rejection to coolant and oil, starting from the heat coming from the combustion of the engine. It will then pass to the engine surface temperatures evaluated in specific interfaces. This approach allows a bi-directional integration between engine model and hydraulic model, instead of the commonly used map based approach in which the integration is impossible. The advantage of having this integration even at HiL and Simulator level is clear because of the more accurate results given. The aim of the present activity is to build a Thermal Mass model which allows this step forward. Moreover, the methodology followed try to be as general as possible with the aim of finding a general way to build a similar Thermal Mass model even for different engine layouts.