Abstract

Increasing regulatory and commercial requirements have led to widespread adoption of digital analysis in the IC engine design process. This has helped to improve fuel efficiency, reduce emissions, as well as reduce reliance on physical testing and the development of costly prototypes. CFD is one of the key types of analysis employed in generating a digital twin of the IC engine. It is it able to model a wide range of physical processes that include gas and coolant flow, combustion, emissions and conjugate heat transfer (CHT). When using CFD to evaluate the thermal field of engine components, the most common approach is to generate separate models for the gas flow and combustion (the in-cylinder model), and the coolant flow and metal temperatures (the CHT model). The in-cylinder model is used to estimate spatially varying heat flux which are averaged over a cycle and then applied as thermal boundary conditions to the CHT model. Spatially varying temperatures on the combustion boundaries from the CHT simulation can be then passed back to the in-cylinder simulation and data exchanged between the two simulations until convergence is achieved. Traditionally the in-cylinder and CHT models have been generated using separate software packages. Within the digital environment, this has created a few challenges relating to efficient and accurate data exchange between the two models as well as overall process automation. This paper presents a coupled in-cylinder/CHT approach carried out using a single software package that employs state of the art physics models for both the in-cylinder and CHT analysis. It highlights how integrating both analyses into a single user environment can help to make the process more streamlined, efficient and automated. The approach is applied on a 4-stroke gasoline engine and comparison of the predicted in-cylinder combustion performance and component temperatures are made with experimental measurements.