Optimisation of the Flow Process in Engine Bays - 3D Modelling of Cooling Airflow

The focus of today’s automotive industry is to reduce emissionsand fuel consumption of all vehicles. Concentrating on the truckindustry, the last 20 years have focused largely on cutting emissionsof particulate matter and nitrogen oxides. For the future, attentionwill be on fuel consumption and emissions of carbon dioxide.Significant changes have been made to fulfill new emission legislations,but the basic vehicle architecture has been kept. New aftertreatment systems that increases the thermal loading of the coolingsystem have been added within the same packaging envelope as before.This means that there is less space to evacuate cooling airflowtoday and more airflow than ever is required.Furthermore, project costs have increased over the years, focus isalso on cutting cost and lead times. Thus virtual development earlyin the project is highly desirable. Long before any prototypes areavailable, companies must now answer the question; will this truckhave competitive performance? As the project progresses, redesignsbecome more expensive. Development time is becoming more andmore limited, meaning any changes tend to become major changes.This has lead to a new focus of detailed and accurate simulations ofvehicle performance. For these reasons, in the context of underhoodthermal management, this project has been carried out; to improveand optimise the flow process in engine bays.3D CFD supported by 1D models and measurements has beenstudied to predict the cooling airflow in the engine bay of trucks.The conclusions are that there are good opportunities to simulatethe flow process in engine bays early in development projects. Thisresearch project presents several different methods that, for differentdegrees of effort deliver different accuracy and indications arethat simulation can replicate measurements. This is though, withadvanced simulation models and a lot of computational effort, atleast seen from today’s perspective