Investigations of Crank Offset and It's Influence on Piston and Piston Ring Friction Behavior Based on Simulation and Testing

Ragot, Patrick; Rebbert, Martin

doi:10.4271/2007-01-1248

Cited by 7 publications

(5 citation statements)

References 1 publication

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“…20, the crank offset induces higher squeeze-film action, w * s , which in the case of the thrust side increases the load-carrying capacity of the contact (for the same side force a greater lubricant film is attained), thus reducing the incidents of asperity interactions at dead centres. Similar trend was observed by Ragot and Rebbert [29] in their experiments. Note that the given friction force in the figure is only for piston skirt to bore contact and it does not include that of the piston rings.…”

Section: Effect Of Crankshaft Offsetsupporting

confidence: 91%

Elasto-multi-body dynamics of internal combustion engines with tribological conjunctions

Perera

Theodossiades

Rahnejat

2010

Proceedings of the Institution of Mechanical Engineers, Part K:

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Reduction of frictional losses and NVH (Noise, Vibration, and Harshness) refinement constitute the key customer-focussed aims in internal combustion engine development. Numerical predictive tools have progressively become an important part of achieving these aims. However, the interactions and sometimes the conflicting requirements of the aforementioned objectives call for the inclusion of many phenomena in realistic models of practical significance. These phenomena occur at varying physics of scale, from micro-scale tribological conjunctions to small scale vibrations and onto large scale inertial dynamics. At the same time, the inclusion of many disciplines for a cohesive analysis will be required, such as rigid body dynamics and elastodynamics, as well as tribology. While the inclusion of such a multi-disciplinary approach is deemed essential, the use of analytical rather than numerical models, as far as possible, would render realistic predictions within the usual tight industrial timescales. This article presents an experimentally validated model of the engine piston assembly, which is based on the multiphysics, multi-scale nature of the interacting components. Furthermore, it provides predictions of some current development trends in engines such as the high output power to weight ratio and offset crankshaft. The emphasis of this article is on the integration of the kinetic reactions arising from the tribological conjunction of the dynamics of engine subsystems, piston, and crankshaft.

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Section: Effect Of Crankshaft Offsetsupporting

confidence: 91%

Elasto-multi-body dynamics of internal combustion engines with tribological conjunctions

Perera

Theodossiades

Rahnejat

2010

Proceedings of the Institution of Mechanical Engineers, Part K:

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“…This ensures that the thrust side's skirt follows the liner through the combustion stroke for a longer period of time. This effect and the resulting friction contribution is reported on by Ragot and Rebbert [30].…”

Section: Resultssupporting

confidence: 66%

Transient Tribo-Dynamics of Thermo-Elastic Compliant High-Performance Piston Skirts

et al. 2013

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Advanced piston technology for motorsport applications is driven through development of lightweight pistons with preferentially compliant short partial skirts. The preferential compliance is achieved through structural stiffening, such that a greater entrainment wedge is achieved at the skirt's bottom edge through thermo-elastic deformation, whilst better conforming contact geometry at the top of the skirt. In practice, the combination of some of these conditions is intended to improve the load-carrying capacity and reduce friction. The approach is fundamental to the underlying ethos of race and high-performance engine technology. Contact loads of the order of 5 kN and contact kinematics in the range 0-35 m/s result in harsh transient tribological conditions. Therefore, piston design requires detailed transient analysis, which integrates piston dynamics, thermo-elastic distortion and transient elastohydrodynamics. The paper provides such a detailed analysis as well as verification of the same using noninvasive ultrasonic-assisted lubricant film thickness measurement from a fired engine under normal operating conditions, an approach not hitherto reported in literature. Good agreement is noted between measured film thickness and predictions.

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“…A multi-body simulation was employed to analyze a wide range of different engine working conditions and different crank offset values. 73 McClure and Tian developed a detailed model of piston and bore hot shape geometries. The model comprises piston deformations due to combustion pressure, axial inertia and interaction with the cylinder bore; hydrodynamic pressure at the skirt/liner interface is neglected to reduce calculation time.…”

Section: Boundary and Mixed Lubricationmentioning

confidence: 99%

Piston dynamics, lubrication and tribological performance evaluation: A review

Delprete

Razavykia

2018

International Journal of Engine Research

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Mechanical power loss of lubricated and bearing surfaces serves as an attractive domain for study and research in the field of internal combustion engines. Friction reduction at lubricated and bearing surface is one of the most cost-effective ways to reduce gas emission and improve internal combustion engines’ efficiency. This thus motivates automotive industries and researchers to investigate tribological performance of internal combustion engines. Piston secondary motion has prime importance in internal combustion engines and occurs due to unbalanced forces and moments in a plane normal to the wrist pin axis. Consequently, piston executes small translations and rotations within the defined clearance during the piston reciprocating motion. Mechanical friction power loss and lubrication at piston skirt/liner and radiated engine noise are dramatically affected by piston secondary dynamics. The lubrication mechanism, piston secondary motion and tribological performance are affected by piston design parameters (piston/liner clearance, wrist pin offset, skirt profile, etc.), lubricant rheology, oil transport mechanism and operating conditions. Therefore, this review is devoted to summarize the synthesis of main technical aspects, research efforts, conclusions and challenges that must be highlighted regarding piston skirt/liner lubrication and piston dynamics and slap.

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Investigations of Crank Offset and It's Influence on Piston and Piston Ring Friction Behavior Based on Simulation and Testing

Cited by 7 publications

References 1 publication

Elasto-multi-body dynamics of internal combustion engines with tribological conjunctions

Elasto-multi-body dynamics of internal combustion engines with tribological conjunctions

Transient Tribo-Dynamics of Thermo-Elastic Compliant High-Performance Piston Skirts

Piston dynamics, lubrication and tribological performance evaluation: A review

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