A survey of the characteristics of the noise emitted by commerical vehicles has been made. The most important single parameter determining the noise of a modern diesel- engined vehicle is the engine speed. All of the other parameters such as load, road speed, etc., have only a noise. This is confirmed by the vehicle modifications reviewed and it is shown how the characteristics of these sources determine the overall noise characteristics of the vehicle. It has been found that a simple model of the vehicle as a number of coincident point sources predicts the overall noise characteristics of the vehicle to plus or minus 2 dB(A). It is shown that there are two extremes of behaviour, the rolling noise controlled vehicle and the power unit noise controlled vehicle; the engine is currently controlling noise sources. Tyre noise has been investigated in some detail as comparatively little has been published previously on this source. Empirical relationships between the tyre noise and speed, tyre size and road surface roughness are given. It is concluded that tyre noise is generated by impacting between elements of the tyre tread and elements of the road surface. Modifications have been made to the engine, exhaust, intake and cooling fan of a 9 ton, 6 litre diesel engined truck which have reduced its ISO test noise level from 88 dB(A) to 80 dB(A). However, it is concluded that 80 dB(A) commercial vehicles are not yet feasible for production. In particular insufficient is known about cooling fan design. Finally cab noise has been investigated and it has been found to originate from the same source as the exterior noise, power unit airborne noise. Therefore any modifications to the power unit to reduce exterior noise will have a similar effect on interior

  • Availability:
  • Corporate Authors:

    Academic Press Incorporated

    Berkeley Square House, Berkeley Square
    London W1,   England 
  • Authors:
    • Waters, P E
  • Publication Date: 1974-7-22

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00134727
  • Record Type: Publication
  • Source Agency: Highway Safety Research Institute
  • Files: TRIS
  • Created Date: Jul 22 1976 12:00AM