Exterior Engine Noise Prediction Utilizing an Acoustic Tube by the Volume Velocity Measurement Method

An acoustic tube was developed and applied to measure the engine radiation noise for the prediction of the steady state exterior engine noise. Using accelerometers to measure the engine surface vibration is a difficult task, especially for the places like the exhaust manifold. The proposed method, an acoustic tube containing a microphone is set at a given distance from the engine and measurements were carried out in such a way that the whole engine surface was covered. Exterior engine noise at a certain distance from the vehicle was predicted by using the measured volume velocity values and propagation characteristics. The predicted results agreed well with previously experimented values.