Title: Portable NVH Dynamometers
text: Noise Vibration and Harshness (NVH) characteristics have become a key differentiator between “Good” vehicles and “Best-In-Class” vehicles. While all OEM's and most Tier 1 suppliers have on-site in-ground chassis dynamometers, a need was identified to design, develop and bring to market, a fully capable portable NVH full vehicle chassis system. The original concept entailed a device, which could be brought to the customer's location, be fully self contained, requiring no external power, and provide data acquisition using transducers that would not contact the vehicle. With traditional instrumentation taking several hours to install, non-contacting lasers would be used to provide significant timesaving, and prevent any possible damage to the vehicle from pinched wires. The new methodology should provide data acquisition in as little as 20 minutes. Analysis would be accomplished immediately following testing, with hard copies available before the next vehicle was ready to run. Full vehicle NVH root cause analysis, including system balancing would be done in minutes, at the customer's location, assembly plant, engineering center, or Visteon site. Along with the NVH capabilities, performance data would also be available including horsepower, fuel testing, etc. This paper presents history, design, development, implementation, use, and future developments for the Visteon Portable NVH/Performance Dynamometers that are now in service. Showcasing how the portable dynamometers support a vehicle level NVH design methodology is presented, which seeks an optimum balance of system design criteria. This is possible by providing bumper-to-bumper NVH root cause analysis, driveline imbalance sensitivity to first order forces, driveline imbalance cross-talk analysis, wheel/tire imbalance and force variation sensitivity, system resonance identification, and dynamic mount transmissibility analysis.