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The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle-level fuel consumption. Specifically, the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. Electric and hybrid electric vehicles do not typically utilize IC engines for low-speed operation. Under these low-speed operating conditions, the vehicles are much quieter than conventional IC engine-powered vehicles, making their approach difficult to detect by pedestrians. To mitigate this safety concern, many manufacturers have synthesized noise (using exterior speakers) to increase detection distance. Further, the US National Highway Traffic Safety Administration (NHTSA) has provided recommendations pursuant to the Pedestrian Safety Enhancement Act (PSEA) of 2010 for such exterior noise signatures to ensure detectability.

The automotive industry continues to develop technologies for reducing vehicle fuel consumption. Specifically, vehicle lightweighting is expected to be a key enabler for achieving fleet CO2 reduction targets for 2025 and beyond. Hybrid glass laminates that incorporate fusion draw and ion exchange innovations are thinner and thereby, offer more than 30% weight reduction compared to conventional automotive laminates. These lightweight hybrid laminates provide additional benefits, including improved toughness and superior optics. However, glazing weight reduction leads to an increase in transmission of sound through the laminates for certain frequencies. This paper documents a study that uses a systematic test-based approach to understand the sensitivity of interior vehicle noise behavior to changes in acoustic attenuation driven by installation of lightweight glass.

The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle-level fuel consumption. Specifically, the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. This will also include a strong growth in the global demand for electric drive units (EDUs). The change from conventional vehicles to vehicles propelled by EDUs leads to a reduction in overall vehicle exterior and interior noise levels, especially during low-speed vehicle operation. Despite the overall noise levels being low, the NVH behavior of such vehicles can be objectionable due to the presence of tonal noise coming from electric machines and geartrain components as well as relatively high shares of road/wind noise. In order to ensure customer acceptance of electrically propelled vehicles, it is imperative that these NVH challenges are understood and solved.

Environmental noises such as wind, road, powertrain, and HVAC noise are important aspects to consider when implementing a hands-free terminal for mobile phone calling from within a car. Traditionally, these environmental noises have been exclusively considered for driver comfort; however, with the introduction of the hands-free terminals (HFT) and increasing consumer demand relative to mobile phone call quality, a broader implication of high background noise levels should be considered. HFT algorithm development and implementation can and does provide a high level of background noise suppression to mitigate these concerns, but this is often done at the expense of computational power and cumulative delay during a phone call. The more advantageous solution would be to address the problem from a source and path perspective with emphasis on reduction of noise in the frequency bands which most influence call quality performance.

It is a common practice to conduct NVH fingerprinting and benchmarking assessments at the powertrain level, to understand source level noise and vibration. To assess the NVH influence of engine, e-motor, and transmission, sub-system testing is often conducted in addition to full powertrain testing. These powertrain or sub-system investigations provide valuable information regarding the status of “source” level excitations relative to targets and / or competitive powertrains. In the case of transmissions and e-machines, it is particularly important to understand source level tonal content and how this will be perceived at the vehicle level. However, variation in component design results in differences in order content, which complicates the process of objectively comparing multiple products. Multiple methods are presented here for characterizing tonal content of transmission and e-machines, based on assessments conducted in a component hemi-anechoic dynamometer test cell.