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Sound Optimization for Downsized Engines
ISSN: 0148-7191, e-ISSN: 2688-3627
Published June 30, 2014 by SAE International in United States
Annotation ability available
Event: 8th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference
Today, the number of downsized engines with two or three cylinders is increasing due to an increase in fuel efficiency. However, downsized engines exhibit unbalanced interior sound in the range of their optimal engine speed, largely because of their dominant engine orders. In particular, the sound of two-cylinder engines yields half the perceived engine speed of an equivalent four-cylinder engine at the same engine speed. As a result when driving, the two-cylinder engine would be shifted to higher gears much later, diminishing the expected fuel savings.
This contribution presents an active in-car sound generation system that makes a two-cylinder engine sound like the more familiar four-cylinder engine. This is done by active, load-dependent playback of signals extracted from the engine vibration through a shaker mounted on the firewall.
A blind test with audio experts indicates a significant reduction of the engine speed when shifting to a higher gear. In the blind test, experts favored the interior sound of the proposed sound generation system and perceived better interaction with the vehicle.
CitationSontacchi, A., Frank, M., Zotter, F., Kranzler, C. et al., "Sound Optimization for Downsized Engines," SAE Technical Paper 2014-01-2040, 2014, https://doi.org/10.4271/2014-01-2040.
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