Title: Application of acoustic arrays on automotive turbocharger environments
Over the years, automobiles have undergone a great extent of refinement in pursuit of improved design, higher fuel efficiency, lower emissions and increased user comfort. From the perspectives of user comfort and government regulations, reduced noise emissions and improved interior acoustics in vehicles have become a priority as original equipment manufacturers (OEMs) and component suppliers have made great strides in providing products with reduced vibro-acoustic response.
Turbocharging has become increasingly common in all categories of automobiles to achieve downsizing of engines, increase in power rating, improvement of fuel efficiency and reduction in emissions. However, a turbocharger is also a source of considerable vibro-acoustic excitation and can potentially emit high frequency noise and cause other vehicle components to radiate high frequency noise.
In this context, identification and understanding of turbo noise sources and radiating surfaces (of turbo itself and other engine components) is very helpful to act on primary and secondary turbo vibration and noise transfer path for turbo noise reduction. For these reasons, Garrett Advancing Motion equipped 3 R&D sites in France, India, and China, with Simcenter Testlab HD Acoustic Camera systems to implement acoustic imaging techniques in different turbo testing environments. Quick transient conditions of turbocharger operation, different types of noise signatures and background noise conditions make the exercise difficult, but the HD Acoustic Camera system with its microphones array and beamforming & focusing techniques enable sound source localization and acoustic power quantification in near field conditions with relative ease.
Many case studies done in recent years have shown interesting results, and also technical difficulties to consider, to improve acoustic imaging techniques applied in turbo environment. Regardless of challenges, acoustic imaging remains a very promising and efficient method in noise source identification and quantification, while enabling easy understanding and interpretation of results by means of visualizing the noise.