A New Measurement Method for Separating Airborne and Structure Borne Sound From An I.C. EngineS Valve Train Mechanism

Document Number: 931335

Date Published: May 1993

Author(s):
D. Anderton - University of Southampton
J. H. Zheng - University of Southampton

Abstract:
With the introduction of lean burn and multivalve technology to produce gasoline engines with power outputs above 50 kW/litre there has also been an increasing interest in baseline engine noise. One component of this is due to the operation of valve train mechanism. The work described in this paper concentrates on this aspect of engine noise and uses a motoring rig to allow a full assessment of the problem. Usually the noise of the valve train mechanism is measured outside the valve cover. Here both noise inside and outside the valve cover is assessed using an extension of the acoustic substitution technique and the individual contribution of both airborne and structure borne noise assessed. It is found that airborne noise generated by the valve mechanism inside the valve cover and transmitted through the cover can be a major noise source at low frequencies (200 - 1200 Hz) and higher engine speeds. Thus design for low noise must consider not only structural response, damping and isolation but also the acoustic transmission loss properties of the valve cover.

File Size: 352K
Product Status: In Stock

See other papers presented at Noise & Vibration Conference & Exposition, May 1993, Traverse City, MI, USA, Session: Noise & Vibration Conference & Exposition

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