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How Can Active Exhaust Systems Contribute to the Reduction of CO 2 Emission and Comply with Future Pass-By Noise Limits?
ISSN: 2641-9637, e-ISSN: 2641-9645
Published September 30, 2020 by SAE International in United States
Event: 11th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference
Citation: Krueger, J., Wink, P., and Werner, M., "How Can Active Exhaust Systems Contribute to the Reduction of CO2 Emission and Comply with Future Pass-By Noise Limits?," SAE Int. J. Adv. & Curr. Prac. in Mobility 3(2):1075-1080, 2021, https://doi.org/10.4271/2020-01-1534.
The pass-by noise limits of passenger vehicles according to ISO 362 / R51.03 [1, 2] will be further reduced by 2 dB in 2024 in Europe. Since the pass-by noise is substantially influenced by exhaust noise, the effort for the exhaust system needs to be increased substantially. This results in systems with larger mufflers or higher backpressure. However, the more stringent CO2-emission targets require ever more efficient powertrains, which calls for rather lower backpressure to optimize the engine design.
This paper describes how compact active exhaust lines can support a design for low backpressure and high acoustic attenuation at the same time. For two passenger vehicles with gasoline engines active exhaust lines are investigated in detail and the results are compared to the series production exhaust lines. Thus, in one exemplary case, the pass-by noise of a limousine could be reduced from 70 dB(A) to 68 dB(A) without any change in the vehicle design except the improved exhaust system. In a second example, the backpressure of a passenger vehicle was reduced by > 100 mbar and at the same time a lower tailpipe noise could be achieved with essentially the package space.