•3D CFD modelling of buoyancy-driven convection flow resolved on full-geometry vehicle.•Convective heat transfer coefficients characterised during natural soak environment.•Coupled transient CFD - ...heat transfer modelling analysis was demonstrated.•9 h cool-down behaviours of the key engine fluids were resolved.•A CAE tool developed enabling evaluations of heat retention and encapsulation design.
This paper investigates transient heat transfer processes of a vehicle under-bonnet region during natural soak condition using computer aided engineering (CAE). Heat reserved within the engine bay is beneficial to the engine cold-start for potentially reductions in friction losses, CO2 emissions and fuel consumption. Buoyancy-driven convection, thermal radiation and conduction are key contributors to heat transfer processes of engine compartments during soak. In this study, a coupled transient 3D computational fluids dynamics (CFD) – heat transfer modelling method was studied in a passenger vehicle to simulate its 9 h cool-down behaviours. The developed CAE method was able to predict the temperature cool-down of the key fluids of good agreement with experiments. Potential air and heat leakage paths around the engine bay were identified. The flow development during the early stage (0–2 h) of the soak was vital to accurate prediction of the heat transfer coefficients for the heat retention modelling, where convection and radiation have played important parts. Optimum simulation strategy was obtained with reduced simulation time and good prediction accuracy. This further allows the integration of engine encapsulation design for optimising fuel consumption and emissions in a timely and robust manner, aiding the development of low-carbon transport technologies.
•Overviews the current developments in modelling tools for thermal management of hybrid vehicles.•Co-simulation enables whole vehicle model architecture development with reduced costs.•Thermal ...subsystem model and optimisation further request the development of fast running models.•Heat retention modelling work shows effectively reducing CO2 emissions and 2.5% fuel savings.
Thermal management plays a vital role in the modern vehicle design and delivery. It enables the thermal analysis and optimisation of energy distribution to improve performance, increase efficiency and reduce emissions. Due to the complexity of the overall vehicle system, it is necessary to use a combination of simulation tools. Therefore, the co-simulation is at the centre of the design and analysis of electric, hybrid vehicles. For a holistic vehicle simulation to be realized, the simulation environment must support many physical domains. In this paper, a wide variety of system designs for modelling vehicle thermal performance are reviewed, providing an overview of necessary considerations for developing a cost-effective tool to evaluate fuel consumption and emissions across dynamic drive-cycles and under a range of weather conditions. The virtual models reviewed in this paper provide tools for component-level, system-level and control design, analysis, and optimisation. This paper concerns the latest techniques for an overall vehicle model development and software integration of multi-domain subsystems from a thermal management view and discusses the challenges presented for future studies.
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