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Refinement of Engine In-Cycle Losses of Parasitic and Errant Dynamic Nature

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Shape of Bore
Analysis of Cylinder Liner: Crucial role of ring-bore conjunction 



Elastodynamics of Compression Ring


The ring is subjected to global modal behaviour due to net applied forces 


Top images represent a Mode Shape comparison; white background numerical analysis, blue background FEA shapes. Left and right images are Mode Shape 2 and 3 respectively.



The parameters influencing the trybodynamics of ring-bore include:

·         Surface profile of ring (new and worn) and surface topography of liner

·         Geometry of bore/liner

·         Thermo-mechanical properties of ring and liner materials and protective coatings

·         Deformation behaviour of ring and bore/liner including thermoelastic deformations and elastodynamics

·         Lubricant rheology and physical chemistry

·         Contact kinematics and loading

·         Lubricant transport and regime of lubrication



        Elastostatics and Elastodynamics of Cylinder Bore



A measured bore profile; The bore outroundness must be addressed in any analysis.



 The bore is NOT an ideal circular cylinder due to the following conditions:
  • Inability in producing a perfectly circular cylinder in practice (2nd order deformations - ovality)

  • Deformations induced by finishing and machining processes such as honing (3rd order deformations)

  • Deformations induced during fitment; e.g. fastening cylinder head bolts (4th order deformations)

  • Other higher order mechanical deformations induced during operation (elastodynamic analysis of the bore) 
  • Deformations of thermoelastic nature