Abstract
ECE R51 proposes more stringent limit values for noise emission than the values currently in force. In order to control the pass-by noise, we need to control the noise level of the main assembly or their transfer functions along the transmission path. In traditional Transfer Path Analysis (TPA) model, the near-field sound pressure levels of the main assembly are acting as the ‘source’, and the measurement error is large due to the interference by each other assembly when the test is performed on the vehicle. An anechoic room for high-powered assembly is required when the test is performed on test rig. In this paper, the sound power levels of the main assembly are acting as the ‘source’ on the test rig, can be measured in a normal test room, thus demanding no an anechoic room. Here, the sound sources are represented by a equivalent point sound source. The pass-by noise level can be predicted by using transfer functions between the main assembly and the pass-by noise. An experiment for a heavy truck is designed to validate the noise prediction model.
KEYWORDS Pass-by noise prediction, Transfer path analysis, Airborne transfer function, Monopole sound source, Source strength