Effect of Compression Ring Elastodynamics Behaviour upon Blowby and Power Loss

Baker, Christopher E.; Rahmani, Ramin; Karagiannis, Ioannis; Theodossiades, Stephanos; Rahnejat, Homer; Frendt, Alan

doi:10.4271/2014-01-1669

Cited by 16 publications

(21 citation statements)

References 32 publications

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“…The model is based on that reported by Baker et al [9] who modified the analysis techniques of Gulwadi [48] and Ruddy et al [49].…”

Section: Gas Flow Modelmentioning

confidence: 99%

“…This combination invariably results in mixed or boundary regimes of lubrication, where the direct contact of the surfaces at asperity level is encountered. There is also significant ring elastodynamic behaviour in approaching the TDC in order to seal the combustion chamber [8][9], this being the primary function of the compression ring. In turn, the ideal conformance of the ring to the liner surface can result in increased friction.…”

Section: Introductionmentioning

confidence: 99%

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A Numerical Model to Study the Role of Surface Textures at Top Dead Center Reversal in the Piston Ring to Cylinder Liner Contact

Morris

Rahmani

Rahnejat

et al. 2015

Journal of Tribology

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Minimisation of parasitic losses in the internal combustion engine is essential for improved fuel efficiency and reduced emissions. Surface texturing has emerged as a method palliating these losses in instances where thin lubricant films lead to mixed or boundary regimes of lubrication. Such thin films are prevalent in contact of compression ring to cylinder liner at piston motion reversals because of momentary cessation of entraining motion. The paper provides combined solution of Reynolds equation, boundary interactions and a gas flow model to predict the tribological conditions, particularly at piston reversals. This model is then validated against measurements using a floating liner for determination of in-situ friction of an engine under motored condition. Very good agreement is obtained. The validated model is then used to ascertain the effect of surface texturing of the liner surface during reversals. Therefore, the paper is a combined study of numerical predictions and the effect of surface texturing. The predictions show that some marginal gains in engine performance can be expected with laser textured chevron features of shallow depth under certain operating conditions. Keywords: A c c e p t e d M a n u s c r i p t N o t C o p y e d i t e d

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“…The model is based on that reported by Baker et al [9] who modified the analysis techniques of Gulwadi [48] and Ruddy et al [49].…”

Section: Gas Flow Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Numerical Model to Study the Role of Surface Textures at Top Dead Center Reversal in the Piston Ring to Cylinder Liner Contact

Morris

Rahmani

Rahnejat

et al. 2015

Journal of Tribology

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show abstract

“…However, to find the optimum ring tension, it is also necessary to include the sealing effectiveness and the gas blowby in the analysis. 12 This is addressed elsewhere and is not included in the current work because of the expansive requirements for optimisation-driven simulation studies. For the effect of ring tension to be included in all aspects, ring dynamics and blowby, 12 as well as the cylinder outof-roundness, should also be considered.…”

Section: Objective Functionsmentioning

confidence: 99%

“…12 This is addressed elsewhere and is not included in the current work because of the expansive requirements for optimisation-driven simulation studies. For the effect of ring tension to be included in all aspects, ring dynamics and blowby, 12 as well as the cylinder outof-roundness, should also be considered. 29 With regard to the centre shift (the offset), apart from quite thin rings, a larger offset in the negative direction generally reduces the energy loss.…”

Section: Objective Functionsmentioning

confidence: 99%

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Optimisation of the piston compression ring for improved energy efficiency of high performance race engines

Morris

Mohammadpour

Rahmani

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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The primary function of the piston compression ring is to seal the combustion chamber from the bottom end of the engine. As a result, its conformance to the cylinder liner surface is of prime importance. This close-contact contiguity results in increased friction, making this contact conjunction responsible for a significant proportion of energy losses. The frictional losses can be as much as 2-6% of the expended fuel energy, which is quite significant for such a diminutive contact. Under these conditions, the geometrical profile, the surface topography and the inertial properties of the ring assume significant importance. The paper presents an integrated mixed-hydrodynamic analysis of the compression ringcylinder liner contact with multi-parameter optimisation, based on the use of a genetic algorithm. The multi-objective functionality includes minimisation of the parasitic energy loss, reduction in the incidence of asperity level interactions as well as minimisation of the ring mass. Both cold running engine conditions and hot running engine conditions in line with the New European Drive Cycle were considered. Hitherto, such an approach has not been reported in the literature.

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The effect of cylinder liner operating temperature on frictional loss and engine emissions in piston ring conjunction

et al. 2017

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Effect of Compression Ring Elastodynamics Behaviour upon Blowby and Power Loss

Cited by 16 publications

References 32 publications

A Numerical Model to Study the Role of Surface Textures at Top Dead Center Reversal in the Piston Ring to Cylinder Liner Contact

A Numerical Model to Study the Role of Surface Textures at Top Dead Center Reversal in the Piston Ring to Cylinder Liner Contact

Optimisation of the piston compression ring for improved energy efficiency of high performance race engines

The effect of cylinder liner operating temperature on frictional loss and engine emissions in piston ring conjunction

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