Virtual Acoustic Prototyping of Automotive Boosting Systems in Vehicle Environment, a Hybrid Approach 2023-01-1147

Current trends of advanced automotive engines focus on downsizing, better fuel efficiency, and lower emissions, which lead to several advancements in turbocharger designs and technology. More recent trends in electric and hybrid powertrains have further brought additional sources into the NVH balance. With vehicle environments becoming quieter, this has posed a great challenge in controlling undesirable noise from boosting systems. Boosting systems provide oxygen through boosted air pressure, to ICE or fuel cell systems, to improve their efficiency and limit their CO2 and pollutant emissions. Boosting systems are also key elements in current and new electrical and hybrid powertrains. During real driving conditions, the rotational speed of boosting systems (turbomachines and compressors) varies greatly, which makes them produce different noise signatures that can be unpleasant for the end users. In this context, earlier and more realistic noise evaluations are crucial in evaluating the impact a design has on the final acoustic performance perceived by the end user in the vehicle cabin environment. This requires a combined assessment of the acoustic sources from boosting systems, the other vehicle interior noise sources, and the acoustic transfer path from the boosting system to the vehicle cabin. Performing such an assessment experimentally cannot be done early in development with representative hardware and can be expensive. Also, managing such an assessment entirely through simulations is very complex and error prone. The present study proposes a hybrid approach to tackle this noise challenge. This methodology combines the noises of high-speed rotating machine simulated by Garrett’s internal rotordynamic and electromagnetic simulation processes, their transformation from frequency to time domain, and coupling with experimental vehicle noise data. This methodology makes it possible to virtually recreate an acoustics scenario at vehicle cabin level in realistic vehicle operating conditions. This enables earlier, faster and easier objective and subjective evaluation of noise response as a function of component design changes, vehicle transfer function, and drive cycles, which are critical in determining the right corrective actions to mitigate potential noise risks in vehicle.