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Automatic engine start/stop systems are becoming more prevalent and increasing market share of these systems is predicted due to demands on improving fuel efficiency of vehicles. Integration of an engine start/stop system into a “conventional” drivetrain with internal combustion engine and 12V board system is a relatively cost effective measure to reduce fuel consumption. Comfort and NVH aspects will continue to play an important role for customer acceptance of these systems. Possible delay during vehicle launch due to the engine re-start is not only a safety relevant issue but a hesitating launch feel characteristic will result in reduced customer acceptance of these systems. The engine stop and re-start behavior should be imperceptible to the driver from both a tactile and acoustic standpoint. The lack of masking effects of the engine during the engine stop phases can cause other “unwanted” noise to become noticeable or more prominent.

Integration of automatic engine Stop/Start systems in “conventional” drivetrains with 12V starters is a relatively cost-effective measure to reduce fuel consumption. Therefore, automatic engine Stop/Start systems are becoming more prevalent and increasing market share of such systems is predicted. A quick, reliable and consistent engine start behavior is essential for customer acceptance of these systems. The launch of the vehicle should not be compromised by the Stop/Start system, which implies that the engine start time and transmission readiness for transmitting torque should occur within the time the driver releases the brake pedal and de-presses the accelerator pedal. Comfort and NVH aspects will continue to play an important role for customer acceptance of these systems. Hence, the engine stop and re-start behavior should be imperceptible to the driver from both a tactile and acoustic standpoint.

The sound quality and performance of an automotive engine are both significantly influenced by the “air-to-air” system, i.e., the intake system, the exhaust system, and the engine gas dynamics. Only a full systems approach can result in an optimized air-to-air system, which fulfills engine performance requirements, overall sound pressure level targets for airborne vehicle noise, as well as sound quality demands. This paper describes an approach, which considers the intake system, engine, and exhaust system within one CAE model that can be utilized for engine performance calculations as well as acoustic simulations. Examples comparing simulated and measured sound are discussed. Finally, the simulated sound (e.g., at the tailpipe of the exhaust system) is combined with an interior noise simulation technique to evaluate its influence inside the vehicle's interior.

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 electrification of vehicle propulsion has caused a significant change in many areas including the world of vehicle acoustics. Comments from the media currently range from “silently hums the future” to “electric car roars with V8 sound”. Decades of experience in designing brand-specific vehicle sound based on noise and vibration generated by combustion engines cannot be simply transferred to the upcoming vehicles driven purely by electric powertrains. Although electric vehicles are almost always considerably quieter than those powered by internal combustion engines, the interior noise is characterized by high-frequency noise components which can be subjectively perceived as annoying and unpleasant. Moreover, such disturbing noise is no longer masked by combustion engine noise. Fundamental questions regarding the sound design of electric vehicles have yet to be answered: it remains unclear what exactly the interior noise of an electric vehicle should sound like.

The electrification of vehicle propulsion has changed the landscape of vehicle NVH. Pure electric vehicles (EV) are almost always quieter than those powered by internal combustion engines. However, one of the key challenges with the development of range extended electric vehicles (ReEV) is the NVH behavior of the vehicle. Specifically, the transition from the EV mode to one where the range extender engine is operational can cause significant NVH issues. In addition, the operation of the range extender engine relative to various driving conditions can also pose significant NVH concerns. In this paper internal combustion engines are examined in terms of their acoustic behavior when used as range extenders. This is done by simulating the vibrations at the engine mounting positions as well as the intake and exhaust orifice noise. By using a transfer path synthesis, interior noise components of the range extenders are calculated from these excitations.

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.

The innovation and application of new technologies in battery electric vehicle (BEV) development continues to be a key objective of the automotive industry. One such area of development is glazing designs that reduce transmission of noise into vehicle interiors. Highly asymmetric laminated front side lites that consist of thick soda lime glass exterior plies laminated with thinner ion exchanged interior plies with acoustic polyvinyl butyral interlayers offer substantially reduced noise transmission compared to industry standard monolithic front side lites. These asymmetric laminate designs also provide additional benefits of improved toughness and penetration resistance. 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 asymmetric laminated glass front side lites.