This paper describes the contributions of individual parts to the overall noise produced, and shows how this noise varies with operating conditions. Methods of reducing noise are discussed. It is shown that engine combustion produces most noise, but the fan, exhaust system and air intake also contribute. The path which the combustion noise takes is described and methods of reducing it are mentioned. Predictions of engine noise can be based solely on engine speed and cylinder bore. It is claimed that combustion noise can be reduced by 5.5 dba at normal running speeds by introducing a pilot injection system; indirect injection engines are quieter than direct injection engines. Methods of reducing the transmission of combustion noise by structural changes are examined. Any future legislation on vehicle noise should not be made without economic considerations; reducing the noise contribution of sources other than the engine will be difficult and costly. /TRRL/

  • Corporate Authors:

    British Acoustical Society

    1 Bridcage Walk
    London SW1,   England 
  • Authors:
    • Challen, B J
  • Publication Date: 1973

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 4 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00127805
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Proceeding
  • Files: ITRD, TRIS
  • Created Date: Dec 3 1975 12:00AM