Current approaches to heat rejection prediction during the development stage of a new engine are mostly based on maps built upon experimental data. However, these maps can be obtained fairly late in the development process, when at least a prototype of the engine can be run on the test bench. Furthermore, such experimental maps are limited to a discrete number of points measured at fixed operating conditions.
An innovative approach based on 1D simulation was tested in the commercial 1D multi-physics code GT-SUITE, developed by Gamma Technologies LLC, to advance the moment at which reliable heat rejection calculations can be effectively used to support the engine and cooling system design. A fully physical Diesel engine performance model - featuring a predictive combustion model - was integrated with a detailed finite element wall temperature solver based on the 3D meshing feature available in GT-SUITE. Coolant and oil hydraulic circuits were implemented in the model and used to predict flow rate through the water jacket and oil gallery. In addition, a predictive detailed friction model of the cranktrain was built to better capture the interactions between metal and oil from the thermal standpoint.
The integrated model was eventually validated against experimental measurements and it proved to be an effective means to predict heat rejection when test data are not available yet. The predictive capabilities characterizing this model would allow to assess the impact on heat rejection and engine heat distribution given by a different engine calibration, components and operating conditions, with a noticeable saving of time and money compared to a traditional, fully-experimental-based engine development process.