Development of a Mathematical Model for Predicting Energy Losses in Internal Combustion Engines During Thermomechanical Conversion Processes

The paper will provide the formulation, construction and testing of a high fidelity, entirely deterministic mathematical model intended to simulate and measure energy losses in an Internal combustion engine (ICE) during thermomechanical conversion processes. In order to remove stochastic variations and assure a strict compliance with the First Law of Thermodynamics, the open thermodynamic system equations of motion were discretized and solved at a very fine spatiotemporal resolution of 0.1 Crank Angle Degrees (CAD). The chemical energy release of the fuel (2.125 kJ/cycle) was modeled with an advanced Double Wiebe function, where the fast premixed combustion phase and the diffusion phase which was controlled by mixing were strictly separated. The phenomenological Woschni heat transfer correlation was used to obtain dynamic thermomechanical boundary interactions, and mechanical dissipation was measured through Chen-Flynn friction model along with the Vogel oil viscosity equation. These numerical data show a complete global energy balance: 40.70 % of the input chemical energy is transformed into gross indicated work, 31.60 % into exhaust gas enthalpy, 18.11 % into heat loss through in-cylinder wall heat transfer, 6.49 % into mechanical friction and 3.10 percent into pumping work during the gas exchange. The powerful predictive power of this mathematical model has offered an outstanding, noise-free analytical instrument to optimize engine thermal strategies, the potential of waste heat recovery (WHR) as well as reduce parasitic losses in heavy-duty power generation facilities.