Evaluation of Source and Path Contributions to Sound Quality Using Vehicle Interior Noise Simulation 2011-01-1685
It is commonly accepted that refined “powertrain sound quality” is essential to the development of a vehicle which will be well received by today's discriminating automotive customer. However, though there are several metrics which correlate well with a subjective impression of powertrain level inputs, what is ultimately important is the sound quality at driver's ear.
Vehicle level powertrain sound quality is influenced by the powertrain noise and vibration (source) as well as the vehicle airborne and structureborne transfer functions (path). In development as well as benchmarking activities, it can be difficult to separate the influence of source and path on overall vehicle sound quality.
Two unique time domain transfer path analysis techniques will be discussed here, which enable independent evaluations of powertrain and vehicle performance as they relate to sound quality: The Vehicle Interior Noise Simulation (VINS) process is a time domain transfer path analysis (TPA) tool which fully characterizes vehicle transfer functions and predicts driver's ear sound pressure based on powertrain inputs. This tool can provide insight into the specific sources and paths which can drive improvements in vehicle level powertrain sound quality. A derivative of this process is called dBVINS. Rather than characterizing a specific vehicle, the dBVINS process utilizes standard vehicle transfer functions which are based on a database of vehicles to represent an industry median virtual vehicle.
This paper describes the means in which the VINS and dBVINS process can be used together to provide valuable insight during the benchmarking and development processes through independent comparison to targets of powertrain source and vehicle transfer path characteristics.