This paper deals with the sound transmission from the combustion chamber to the external walls in water cooled vertical engines, the influence of cast iron and aluminium as materials for crank cases, the noise of the crank shaft belt pulley as well as the insulation effect of noise insulation units in pipe systems. In the transmission of sound from the combustion chamber to the crank shaft, the distribution of the maximum amplitudes at the sound excitation structure depends mainly on the tendency towards resonance of individual regions of the structure and is almost independent of the distance from the excitation point. The sound transmission route from the combustion chamber to the crank shaft external surfaces across the piston and gears in the middle frequency range, is more important than the transmission route across the cylinder head and block. Theoretical speculations regarding a higher noise level in the case of aluminium engines, scarcely arises in practice. The differences in sound are non-uniform and lie within the range of serious scattering from engine to engine. The excitation of the belt pulley arises primarily from the combustion, and therefore the belt pulley noise can be lowered by a reduction in the roughness of the combustion. The position of the axial bearings of the crank shaft must be considered as well as the mass of the belt pulley and particularly the sound insulation between the belt pulley and the crank shaft or the sound-damping casing of the belt pulley. With corrugated tube compensators, sealing compensators, and rubber tubes with fabric fittings, sound insulation levels can be achieved so that the various exhaust pipes and cooling water pipes which lead outwards in an encased engine can be so well insulated, that their noise level lies within the range of the encased engine itself. /TRRL/

  • Availability:
  • Corporate Authors:

    Franckhlsche Verlagshandlung

    Pfizerstrasse 5, Postfach 640
    7000 Stuttgart 1,   Germany 
  • Authors:
    • Fachbach, H A
    • Thien, G E
  • Publication Date: 1976-7-8


  • German

Media Info

  • Features: Figures; Photos; References;
  • Pagination: p. 269-274
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00179997
  • Record Type: Publication
  • Source Agency: Bundesanstalt für Straßenwesen (BASt)
  • Files: ITRD, TRIS
  • Created Date: Sep 27 1978 12:00AM