The tightening restrictions, in terms of fuel consumption, have pushed the vehicle manufacturers and equipment suppliers into searching for innovative ways to reduce the carbon dioxide emissions. Along with the ameliorations added to the engine itself, additional systems are grafted to the engine in order to keep up with the ever-changing laws.
Isolating the impact on the fuel consumption of an added system, by on board testing, is a complicated task. In this case, using simulation modeling allows the reduction of delays related to prototyping and testing. This paper presents modeling of various thermal systems in a vehicle and their interactions to evaluate the fuel consumption using AMESim software.
As means to reduce the CPU cost of the model (calculation time), without decreasing its predictability, engine modeling has been done by two steps: high frequency model and mean value model. While the first model is used to characterize the engine indicated work, exhaust losses and thermal losses, the second model is integrated in a complete vehicle model where the additional thermal systems are connected. From these additional systems, the model contains: the cooling system, lubricating system, EGR (Exhaust Gas Recirculation) and charged air cooling system.
Using this model helps evaluating the cost of each system in terms of fuel consumption. Comparing different cooling systems architectures is possible. Furthermore, the impact of air shutters on both the aerodynamics and the thermal stability of the engine is studied.