The second part of the article on the reduction of diesel engine noise concentrates on treatments for crankcase and cylinder blocks, valve gear covers and sump. The most important area of the engine surface to consider when planning surface treatments is considered to be the crankcase/cylinder block casting, and the problems associated with modes of vibration which cause significant contributions to the overall noise is discussed. The diagnosis of test results obtained by adopting a multi-stage approach to the problem is described. It is suggested that most of the required results may be obtained from the use of 1/3-octave band surface vibration diagnostic techniques, and the various stages are described in sequence for clarity. Reference is made to associated design modifications, and an example is quoted whereby the vibration at the centre of the crankcase panels of one engine was reduced by 14 db at the first panel resonance and by 4-7 db in 1/3-octave bands below this frequency. Reference is made to the effects of weight and stiffness, and isolation of components and covers by means of rubber gaskets and nebar sandwich materials composed of rubber-bonded cork gasket material covered by steel. The effects of a combination of treatments, leading to a reduction of 5 db or more are graphically illustrated. /TRRL/

  • Corporate Authors:

    Trade and Technical Press, Limited

    Crown House
    Morden, Surrey SM4 5EW,   England 
  • Authors:
    • RUSSELL, M F
  • Publication Date: 1979-1

Media Info

  • Features: Figures; References;
  • Pagination: p. 5-7
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00195530
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Aug 15 1979 12:00AM