Study of the Generation mechanism for Abnormal Exhaust Noise

871924

10/01/1987

Event
Passenger Car Meeting & Exposition
Authors Abstract
Content
Based on experimental analysis, the generation mechanism of abnormal exhaust noise which is characterized by an intermittent high frequency aetallic sound, is clarified by bench testing of a FWD vehicle.
The noise is caused by large amplitude pressure waves (finite amplitude waves) in the exhaust pipe. They are amplified due to interference between reflected waves and subsequent waves from the engine, and are finally transformed into shock waves in the propagation process along the exhaust pipe, resulting in abnormal exhaust noise. By theoretical analysis of finite amplitude waves, the wave profile in the propagation process and the transition distance to the shock wave can be solved analytically where the assumptions of mass, momentum, and energy conservation are valid, until the moment of shock wave formation. The transition distance is a key parameter in analyzing the growth and existence of shock waves. This paper proposes a simulation method for estimating the transition distance which enables the generation of abnormal exhaust noise.
Meta TagsDetails
DOI
https://doi.org/10.4271/871924
Pages
16
Citation
Okada, M., Abe, T., and Inaba, M., "Study of the Generation mechanism for Abnormal Exhaust Noise," SAE Technical Paper 871924, 1987, https://doi.org/10.4271/871924.
Additional Details
Publisher
Published
Oct 1, 1987
Product Code
871924
Content Type
Technical Paper
Language
English