Experimental investigation of transmission loss in an automotive turbocharger compressor under ideal and real engine operating conditions

Acoustic transmission losses are expected to occur over the turbocharger compressor, especially along its rotating wheel section. Experiments on the acoustic characteristics of automotive turbocharger compressors were performed to investigate this acoustic transmission loss behavior. Two different rotor sizes were acoustically investigated considering approximately the same performance characteristics of the compressors. The investigated variants passed through two phases of measurements: The first phase was performed under ideal operating conditions involving a steady non-pulsating flow on an acoustic component test rig for turbochargers. Whereas the second phase was conducted under real engine operating conditions including pulsating flow of a modern 6-cylinder gasoline engine on an engine test rig. Comparisons between the two measurement phases show a considerable agreement between the two test rig setups for different operating conditions.