Systems integration is one of the current challenges faced by car manufacturers and suppliers, especially in the field of Vehicle Thermal Management. Indeed, in order to ensure low consumption engines conformed to emissions standards, to provide the best comfort possible to passengers (both thermal and mechanical), engineers have to deal with all the interactions between the engine and vehicle thermal subsystems. This paper focuses on the simulation of Heating, Ventilating, and Air Conditioning systems and their integration into a global vehicle model in order to study the impact of such systems of course on passenger comfort, but also on engine thermal management and fuel consumption. The first part details the simulation of an air-conditioning system, including a geometrical modeling of the heat exchangers, resulting in a predictive methodology for testing the impact of design changes. The model of the A/C loop is then connected to a detailed cabin model, taking into account internal and external convection, wall thermal solid capacities, solar heat flux and radiation with ambient. This models allows cabin temperature and humidity calculation. The combined AC – cabin models allow to visualize the effect of component modifications on the passenger comfort. The previous model is embedded in a full vehicle modeling suited for vehicle performance and fuel consumption calculation. The complete model allows now to simulate not only the passenger thermal comfort but also fuel consumption. And it allows to simulate the impact of A/C strategies (link stop and start or air recirculation). Finally, the paper includes an example of cabin heating with the same level of modeling (heating systems, cabin and full vehicle) and the consequent impact on the fuel consumption, through various heating devices (PTC and heat storage tank).
