Influence of Vehicle Exhaust Y-Pipe on Tailpipe Noise

This paper analyzes the relation between sound pressure at tailpipe and exhaust Y-pipe structure. The length of Y-pipe influences sound order distribution that influences customers' responsiveness of sound. The equal Y-pipe remains the firing order and its harmonic contents while suppressing the half order and other whole order sounds. Various lengths of equal Y-pipe also influence the magnitude and frequency distribution of tailpipe noise. An air-to-air (induction-engine-exhaust) CAE model is built to predict tailpipe noise using up-to-date software. The real air-to-air model simulation shows that the 3^rd and 6^th orders are the dominating contents for equal Y-pipe exhaust system in 6-cylinder engine applications. The sound pressure of the half order contents increases with the length difference between two branches of a Y-pipe. The results are useful for exhaust Y-pipe design.