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

Morris, Nicholas J.; Mohammadpour, Mahdi; Rahmani, Ramin; Rahnejat, Homer

doi:10.1177/0954407016686249

Cited by 19 publications

(20 citation statements)

References 37 publications

(69 reference statements)

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“…Piston ring topography, cylinder liner materials, and bearing working conditions must be investigated in detail for optimum friction, wear, and oil control. 2–4…”

Section: Introductionmentioning

confidence: 99%

The effect of square-shaped pockets position in sliding line contacts under mixed regime of lubrication

Zavos

Nikolakopoulos

2018

Proceedings of the Institution of Mechanical Engineers, Part J:

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The production of surface topography by artificial pockets is introduced as a well-known method to reduce friction and wear between conjugating surfaces under different lubrication regimes. As a result, the proper design and position of the pockets are of prime importance. This paper supports that goal and focuses on the contribution of the square-shaped textures in several inlet positions and densities on film thickness and wear of line contacts under mixed lubricated conditions. The applied load, the sliding speed, and the lubricant oil are set on a custom-built block-on-ring test rig. The lubricant film thickness is measured in real time using capacitive sensors. The wear behavior of the pocketed samples is also examined by an optical microscopy before and after the tests. The findings are compared by the results of similar studies. The results showed that using square-shaped pockets with high density in line contacts can pronounce film thickness up to 40% than the sparser pattern, which resulted in lowest level of abrasive wear. The position of the square-shaped pockets comprising the inlet lubricant flow is given a beneficial effect on starvation in line contacts, helping to lubricant replenishment into the contact.

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“…Piston ring topography, cylinder liner materials, and bearing working conditions must be investigated in detail for optimum friction, wear, and oil control. 2–4…”

Section: Introductionmentioning

confidence: 99%

The effect of square-shaped pockets position in sliding line contacts under mixed regime of lubrication

Zavos

Nikolakopoulos

2018

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…They found that good modelling of the three-dimensional ring dynamics is essential in providing realistic results towards the improvement of the piston ring design. Analytical and numerical models of top compression ring dynamics and lubrication were also presented by Morris et al, 15,16 Shahmohamadi et al, 17 Usman et al 18 and Zavos and Nikolakopoulos 19 They concluded that the surface topography, applied load, sliding speed, generated temperature and lubricant availability have a key role in the complexity of the ring–bore interface. Except for the top compression ring operation within the engine, modern pistons need the available amount of oil to reduce contact and wear.…”

Section: Introductionmentioning

confidence: 96%

Measurement of friction and noise from piston assembly of a single-cylinder motorbike engine at realistic speeds

Zavos

Nikolakopoulos

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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This paper presents a thorough experimental study of piston assembly friction and noise in a single-cylinder motorbike engine operating at low speeds. The friction of the piston ring pack is evaluated using a foil strain gauge with minimal cylinder modification on the thrust side. The technique involves transmitting deformations through the cylinder bore and recording reflections from the lubricated interface as the piston assembly passes. Under these conditions, the piston side forces and the thermal deformations on the output side of the strain gauge sensor are critical. Therefore, the proposed methodology is designed under controlled operating conditions. The overall deformation of the piston assembly is analysed to measure the primary reflection due to friction between the piston assembly and the cylinder wall. Simultaneously, the piston assembly noise is recorded on the thrust side of the engine block using a microphone. Taking measured noise data into account, possible piston slap events resulting from varied engine speeds are taken into account using continuous wavelet signal analysis. The calibration procedure for both tests is also illustrated. The measured friction results show that the strain gauge technique is a challenging work in providing realistic results to enhance current technology. For low engine speeds, a higher contribution is noted by boundary friction at the top dead centre reversal, extending to the position of maximum combustion pressure in the power stroke. Furthermore, the main contribution of the piston slap is estimated at the thrust side when the piston assembly passes at the beginning of the combustion stroke. These results can also be attributed as data to validate piston ring models in terms of friction and piston slap.

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“…Typical piston ring/liner operation in an internal combustion engine undergoes a wide range of lubrication regimes during operation [6,7]. For a complete engine cycle of 4-strokes, hydrodynamic viscous shearing appears to dominate along the intake and the exhaust stroke.…”

Section: Introductionmentioning

confidence: 99%

Predictive tool for frictional performance of piston ring-pack/liner conjunction

Tee

Hamdan

Chong

2019

JMES

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Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

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

Cited by 19 publications

References 37 publications

The effect of square-shaped pockets position in sliding line contacts under mixed regime of lubrication

The effect of square-shaped pockets position in sliding line contacts under mixed regime of lubrication

Measurement of friction and noise from piston assembly of a single-cylinder motorbike engine at realistic speeds

Predictive tool for frictional performance of piston ring-pack/liner conjunction

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