Simulation of Pass-by Fan Noise Emissions and Advancing Test Regulations for Heavy-Duty Electric Vehicles

The rapid adoption of electric vehicles (EVs) necessitates updates to the automotive testing standards, particularly for noise emission. This paper examines the vehicle-level noise emission testing of a Nikola Class 8 hydrogen fuel cell electric semi-truck and the component-level noise emission testing needed to create a predictive simulation model using Wave6 software. The physical, component-level noise emission testing focused on individual cooling fans in a semi-anechoic chamber to assess their isolated noise contributions. With this data, an initial model was developed using spatial gradient statistical energy analysis, which successfully predicted pass-by noise levels based on varying fan locations and speeds. Real-world pass-by testing confirmed the model's accuracy across different cooling fan speeds. By leveraging advanced simulation techniques, engineers aim to enhance the accuracy and reliability of pass-by noise predictions through cost-effective studies of architectural changes before implementation. As EVs produce noise differently from internal combustion engine (ICE) vehicles, current industry standardized tests inadequately capture their full noise profiles. This paper highlights the need for regulatory updates to ensure effective pass-by testing for Class 8 electric semi-trucks and other EVs to adequately address their unique noise characteristics. Future work aims to refine the model and tackle issues with existing standards that do not accommodate EV architecture.