Through the years ongoing research has led to considerable improvments in the noise and vibration performances of the DI Diesel engine. It also became clear that in order to reach better results noise and vibration aspects had to be taken into account from the very begining of a new engine design. It is consequently indispensable to have reliable computation prediction tools at one`s disposal which enable the correct simulation of the powertrain vibrations in the acoustic frequency range. The EXCITE software which was developed during the last ten years by AVL seems to fulfill such requirements. As a matter of fact the EXCITE code accurately simulates the different excitation mechanisms involved in powertrain vibrations (combustion, piston slap, valve train) and applies them to a F.E. model of the engine structure. The user experience and expertise, necessary to make these tools effective and reliable, were however still missing.
The DINOISE project aimed at closing this gap. Indeed, the goal of the present project is to acquire the capability of effectively exploiting the potential of the newly developed predicting tools and to identify design methodologies and rules leading to low noise emitting engines.
The approach used in this project consisted in the numerical simulation of two existing "baseline engines" and successively the experimental verification, step by step, of the computational results obtained . Once simulated properly the next step consisted in calculating the effects of different structural adaptions aiming at reduction of radiated noise. The numerically identified structural improvements have subsequently been manufactured resulting in low noise emitting prototypes engines. All calculation results were experimentally validated.