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As the design of engines advances and continues to push the capabilities of current hardware closer to their durability limits, more accurate and reliable analysis is necessary to ensure that designs are robust. This research evaluates a method of conjugate heat transfer analysis for a diesel engine that combines the combustion CFD, Engine FEA, and cooling jacket CFD with the aim of getting more accurate heat loss predictions and a more accurate temperature distribution in the engine than with current analysis methods. A 15.0 L Cummins ISX heavy duty engine operating at 1250 RPM and 15 bar BMEP load is selected for this work. Spray combustion computational fluid dynamics (CFD) simulations are performed for the diesel engine and the results are validated with experimental data. Finite Element Analysis (FEA) simulations were performed in a separate software platform.

As the efforts to push capabilities of current engine hardware to their durability limits increases, more accurate and reliable analysis is necessary to ensure that designs are robust. This paper evaluates a method of Conjugate Heat Transfer (CHT) analysis for a gasoline and a diesel engine that combines combustion Computational Fluid Dynamics (CFD), engine Finite Element Analysis (FEA), and cooling jacket CFD with the goal of obtaining more accurate temperature distribution and heat loss predictions in an engine compared to standard de-coupled CFD and FEA analysis methods. This novel CHT technique was successfully applied to a 2.5 liter GM LHU gasoline engine at 3000 rpm and a 15.0 liter Cummins ISX heavy duty diesel engine operating at 1250 rpm. Combustion CFD simulations results for the gasoline and diesel engines are validated with the experimental data for cylinder pressure and heat release rate.

The development and optimization of two stroke engines, especially the development of internal mixture preparation and the combustion process, require effective and reliable simulation in order to shorten the development time and to reduce prototype and test bench costs. CFD (Computational Fluid Dynamics) is a state of the art tool to optimize and visualize the fluid processes, e.g. scavenging, in-cylinder charge motion, spray formation, mixture preparation or combustion. The drawback of full 3D CFD simulation is the required time for grid generation and calculation of the model, especially for the simulations in the early development phase or in the concept phase as the available time for simulation is limited. Additionally, two stroke specific models e.g. for the reed valve, are not available in commercial 3D CFD codes. In previous investigations [SAE 2005-32-0099] the strategies and the requirements for a predictive simulation have been discussed.