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Bertocchi Enrico - One of the best experts on this subject based on the ideXlab platform.
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Elastohydrodynamic analysis of the Conrod small-end of a high performance motorbike engine via a mass conserving cavitation algorithm
'ASME International', 2015Co-Authors: Mastrandrea, Luca Nicolo', Giacopini Matteo, Dini Daniele, Bertocchi EnricoAbstract:In this contribution a complementarity formulation for the solution of EHL problem in presence of cavitation is employed in order to investigate the tribological behavior of the Conrod small-end of a high performance motorbike engine. The influence of different physical and geometrical parameters is discussed. In particular, the clearance between the Conrod small-end and the piston pin, the lubricant physical properties, the surface roughness and the stiffness of the piston pin are investigated, thus providing preliminary guidelines for the correct design of the coupling. Due to the negligible influence of the transversal forces acting on the Conrod small-end and of the relative sliding speed between the mating surfaces, a two symmetrical model of the assembly is prepared and results are compared with those obtained adopting a simply symmetrical model
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Preliminary investigation of the cavitation damage in the Conrod big end bearing of a high performance engine via a mass-conserving complementarity algorithm
2015Co-Authors: Giacopini Matteo, Bertocchi Enrico, Baldini Andrea, Strozzi AntonioAbstract:The Conrod big end bearing is one of the most critical components of internal combustion engines; it is usually subjected to high dynamic loads and high sliding velocities between contacting surfaces are often involved. Therefore, the tribological behaviour of the Conrod big end bearing is often one of the key elements to engine reliability, and it has been investigated both theoretically and experimentally in several contributions in the pertinent literature [1]. With the ever-increasing quest to improve engine performance, and the consequent increase of the rotational speed and combustion/inertial loads, the cavitation of the lubricant used in Conrod big end bearings may play a crucial role in the assessment of bearing durability. To overcome problems related to film cavitation, palliatives such as the reduction of the clearance between the components, the increase of the oil supply pressure and/or the use of harder coating materials have been commonly adopted. However, such simple adjustments do not always represent a valid solution; further investigations are required in order to avoid cavitation damage occurrence. The cavitation damage has been studied for more than a century both theoretically [2-5] and experimentally [6,7], and many attempts have been made to predict or measure the pressure spikes developing in the cavitated areas due to bubble collapse. Although a universally accepted theory seems not to exist, it is clear that the cavitation damage occurs due to the rapid and violent collapse of the vapour bubbles in the proximity of a solid boundary. The aim of the present work is the preliminary evaluation of the damaging effect of the cavitation in a Conrod big end bearing via elasto-hydrodinamic numerical analyses
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Numerical investigation of the cavitation damage in a high performance engine Conrod big end bearing via a mass-conserving complementarity algorithm
'The Korean Society of Tribologists and Lubrication Engineers', 2014Co-Authors: Dini Daniele, Mastrandrea, Luca Nicolo', Giacopini Matteo, Bertocchi EnricoAbstract:The object of the study is the Conrod big end bearing of an high performance motorbike engine. Comparative analyses involving different geometrical configurations of the crankpin/Conrod assemblies, and in particular of different shapes of the inner profile of the bearing, are presented. The influence of the properties of the lubricant is also discussed. A preliminary cavitation damage index is proposed based on the variation in time of the void fraction at a certain location. The results obtained show a strong influence of the geometry of the bearing on the cavitation phenomenon. Experimental evidence qualitatively agrees with numerical forecasts, thus corroborating the use of both the methodology and the cavitation damage index proposed in this contribution
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ON TORSIONAL VIBRATIONS IN Conrod ASSEMBLIES FOR HIGH PERFORMANCE ENGINES
Editura Mediamira, 2008Co-Authors: Baldini Andrea, Giacopini Matteo, Bertocchi Enrico, Margini Stefano, Rivasi Stefano, Rosi Roberto, Strozzi AntonioAbstract:In the paper, the authors discuss possible causes of Conrod torsional vibrations. Several simplified models are laid out for prediction, evaluation and future research. Some critical remarks about these prospective models are presented. Comparisons with a limited number of experimental cases is finally provided
Giacopini Matteo - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the Influence of Different Asperity Contact Models on the Elastohydrodynamic Analysis of a Conrod Small-End/Piston Pin Coupling
'SAE International', 2018Co-Authors: Ferretti Andrea, Giacopini Matteo, Mastrandrea Luca, Dini DanieleAbstract:Bearings represent one of the main responsible of friction losses in internal combustion engines and their lubrication performance has a crucial influence on the operating condition of the engine. In particular, the Conrod small-end bearing is one of the most critical engine parts from a tribological point of view since limited contact surfaces have to sustain high inertial and combustion forces. In this contribution an analysis is performed of the tribological behaviour of the lubricated contact between the piston pin and the Conrod small-end of a high performance motorbike engine. An algorithm is employed based on a complementarity formulation of the cavitation problem. A comparison between two different approaches to simulate the asperity contact problem is performed, the former based on the standard Greenwood-Tripp theory and the latter based on a complementarity formulation of the asperity contact problem. A model validation is performed by comparing the results with those obtained adopting the commercial software AVL Excite Power Unit. Similar results are obtained from both the approaches, if a proper calibration of the model input data is performed. However, a remarkable sensitivity is highlighted of the results obtained using the Greenwood/Tripp model to the adjustment parameters. The realistic (engineering) difficulty in defining and identifying the roughness data and their purely statistical nature returns results that may be afflicted by a dose of uncertainty. Considering that results of such simulations usually offer guidelines for a correct design of the coupling, further investigations are suggested to identify a relationship between simply available roughness data and model input, starting from a direct experimental measurements of real roughness profiles
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Elastohydrodynamic analysis of the Conrod small-end of a high performance motorbike engine via a mass conserving cavitation algorithm
'ASME International', 2015Co-Authors: Mastrandrea, Luca Nicolo', Giacopini Matteo, Dini Daniele, Bertocchi EnricoAbstract:In this contribution a complementarity formulation for the solution of EHL problem in presence of cavitation is employed in order to investigate the tribological behavior of the Conrod small-end of a high performance motorbike engine. The influence of different physical and geometrical parameters is discussed. In particular, the clearance between the Conrod small-end and the piston pin, the lubricant physical properties, the surface roughness and the stiffness of the piston pin are investigated, thus providing preliminary guidelines for the correct design of the coupling. Due to the negligible influence of the transversal forces acting on the Conrod small-end and of the relative sliding speed between the mating surfaces, a two symmetrical model of the assembly is prepared and results are compared with those obtained adopting a simply symmetrical model
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Preliminary investigation of the cavitation damage in the Conrod big end bearing of a high performance engine via a mass-conserving complementarity algorithm
2015Co-Authors: Giacopini Matteo, Bertocchi Enrico, Baldini Andrea, Strozzi AntonioAbstract:The Conrod big end bearing is one of the most critical components of internal combustion engines; it is usually subjected to high dynamic loads and high sliding velocities between contacting surfaces are often involved. Therefore, the tribological behaviour of the Conrod big end bearing is often one of the key elements to engine reliability, and it has been investigated both theoretically and experimentally in several contributions in the pertinent literature [1]. With the ever-increasing quest to improve engine performance, and the consequent increase of the rotational speed and combustion/inertial loads, the cavitation of the lubricant used in Conrod big end bearings may play a crucial role in the assessment of bearing durability. To overcome problems related to film cavitation, palliatives such as the reduction of the clearance between the components, the increase of the oil supply pressure and/or the use of harder coating materials have been commonly adopted. However, such simple adjustments do not always represent a valid solution; further investigations are required in order to avoid cavitation damage occurrence. The cavitation damage has been studied for more than a century both theoretically [2-5] and experimentally [6,7], and many attempts have been made to predict or measure the pressure spikes developing in the cavitated areas due to bubble collapse. Although a universally accepted theory seems not to exist, it is clear that the cavitation damage occurs due to the rapid and violent collapse of the vapour bubbles in the proximity of a solid boundary. The aim of the present work is the preliminary evaluation of the damaging effect of the cavitation in a Conrod big end bearing via elasto-hydrodinamic numerical analyses
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Numerical investigation of the cavitation damage in a high performance engine Conrod big end bearing via a mass-conserving complementarity algorithm
'The Korean Society of Tribologists and Lubrication Engineers', 2014Co-Authors: Dini Daniele, Mastrandrea, Luca Nicolo', Giacopini Matteo, Bertocchi EnricoAbstract:The object of the study is the Conrod big end bearing of an high performance motorbike engine. Comparative analyses involving different geometrical configurations of the crankpin/Conrod assemblies, and in particular of different shapes of the inner profile of the bearing, are presented. The influence of the properties of the lubricant is also discussed. A preliminary cavitation damage index is proposed based on the variation in time of the void fraction at a certain location. The results obtained show a strong influence of the geometry of the bearing on the cavitation phenomenon. Experimental evidence qualitatively agrees with numerical forecasts, thus corroborating the use of both the methodology and the cavitation damage index proposed in this contribution
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ON TORSIONAL VIBRATIONS IN Conrod ASSEMBLIES FOR HIGH PERFORMANCE ENGINES
Editura Mediamira, 2008Co-Authors: Baldini Andrea, Giacopini Matteo, Bertocchi Enrico, Margini Stefano, Rivasi Stefano, Rosi Roberto, Strozzi AntonioAbstract:In the paper, the authors discuss possible causes of Conrod torsional vibrations. Several simplified models are laid out for prediction, evaluation and future research. Some critical remarks about these prospective models are presented. Comparisons with a limited number of experimental cases is finally provided
Dini Daniele - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the Influence of Different Asperity Contact Models on the Elastohydrodynamic Analysis of a Conrod Small-End/Piston Pin Coupling
'SAE International', 2018Co-Authors: Ferretti Andrea, Giacopini Matteo, Mastrandrea Luca, Dini DanieleAbstract:Bearings represent one of the main responsible of friction losses in internal combustion engines and their lubrication performance has a crucial influence on the operating condition of the engine. In particular, the Conrod small-end bearing is one of the most critical engine parts from a tribological point of view since limited contact surfaces have to sustain high inertial and combustion forces. In this contribution an analysis is performed of the tribological behaviour of the lubricated contact between the piston pin and the Conrod small-end of a high performance motorbike engine. An algorithm is employed based on a complementarity formulation of the cavitation problem. A comparison between two different approaches to simulate the asperity contact problem is performed, the former based on the standard Greenwood-Tripp theory and the latter based on a complementarity formulation of the asperity contact problem. A model validation is performed by comparing the results with those obtained adopting the commercial software AVL Excite Power Unit. Similar results are obtained from both the approaches, if a proper calibration of the model input data is performed. However, a remarkable sensitivity is highlighted of the results obtained using the Greenwood/Tripp model to the adjustment parameters. The realistic (engineering) difficulty in defining and identifying the roughness data and their purely statistical nature returns results that may be afflicted by a dose of uncertainty. Considering that results of such simulations usually offer guidelines for a correct design of the coupling, further investigations are suggested to identify a relationship between simply available roughness data and model input, starting from a direct experimental measurements of real roughness profiles
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Elastohydrodynamic analysis of the Conrod small-end of a high performance motorbike engine via a mass conserving cavitation algorithm
'ASME International', 2015Co-Authors: Mastrandrea, Luca Nicolo', Giacopini Matteo, Dini Daniele, Bertocchi EnricoAbstract:In this contribution a complementarity formulation for the solution of EHL problem in presence of cavitation is employed in order to investigate the tribological behavior of the Conrod small-end of a high performance motorbike engine. The influence of different physical and geometrical parameters is discussed. In particular, the clearance between the Conrod small-end and the piston pin, the lubricant physical properties, the surface roughness and the stiffness of the piston pin are investigated, thus providing preliminary guidelines for the correct design of the coupling. Due to the negligible influence of the transversal forces acting on the Conrod small-end and of the relative sliding speed between the mating surfaces, a two symmetrical model of the assembly is prepared and results are compared with those obtained adopting a simply symmetrical model
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Numerical investigation of the cavitation damage in a high performance engine Conrod big end bearing via a mass-conserving complementarity algorithm
'The Korean Society of Tribologists and Lubrication Engineers', 2014Co-Authors: Dini Daniele, Mastrandrea, Luca Nicolo', Giacopini Matteo, Bertocchi EnricoAbstract:The object of the study is the Conrod big end bearing of an high performance motorbike engine. Comparative analyses involving different geometrical configurations of the crankpin/Conrod assemblies, and in particular of different shapes of the inner profile of the bearing, are presented. The influence of the properties of the lubricant is also discussed. A preliminary cavitation damage index is proposed based on the variation in time of the void fraction at a certain location. The results obtained show a strong influence of the geometry of the bearing on the cavitation phenomenon. Experimental evidence qualitatively agrees with numerical forecasts, thus corroborating the use of both the methodology and the cavitation damage index proposed in this contribution
Gunter Knoll - One of the best experts on this subject based on the ideXlab platform.
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Oilflow Interaction of Engine Bearings
STLE ASME 2008 International Joint Tribology Conference, 2008Co-Authors: Katja Backhaus, Gunter KnollAbstract:To improve calculation of the oil supply to the main and Conrod bearings in the combustion engine, it is possible to simulate plain bearings on a coupled elasto-hydrodynamic basis while allowing for partial-fill states. In an effort to advance the extended simulation technique, software has been developed by the Institute for Machine Components and Design (IMK) at the University of Kassel and validated in experiments. This paper describes the simulation software that has been developed, including the resultant findings on the lubricating oil requirement.Copyright © 2008 by ASME
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oil requirement in main and Conrod bearings
MTZ worldwide, 2006Co-Authors: Gunter Knoll, Katja Backhaus, Michael Berg, Hubert Schultheis, Frankstefan LudwigAbstract:To improve calculation of the oil supply to the main and Conrod bearings in the combustion engine, it is possible to simulate plain bearings on a coupled elastohydrodynamic basis while allowing for partial-fill states. In an effort to advance the extended simulation technique, software has been developed by the Institute for Machine Components and Design (IMK) at the University of Kassel and validated in experiments jointly with IAV GmbH, Chemnitz, within FVV e.V.’s “Oil requirement simulation” project [7]. This paper describes the simulation software that has been developed, including the resultant findings on the lubricating oil requirement, as well as the accompanying tests.
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Oil requirement in main and Conrod bearings: Simulation techniques and experimental validation
MTZ worldwide, 2006Co-Authors: Gunter Knoll, Katja Backhaus, Michael Berg, Hubert Schultheiß, Frankstefan LudwigAbstract:To improve calculation of the oil supply to the main and Conrod bearings in the combustion engine, it is possible to simulate plain bearings on a coupled elastohydrodynamic basis while allowing for partial-fill states. In an effort to advance the extended simulation technique, software has been developed by the Institute for Machine Components and Design (IMK) at the University of Kassel and validated in experiments jointly with IAV GmbH, Chemnitz, within FVV e.V.’s “Oil requirement simulation” project [7]. This paper describes the simulation software that has been developed, including the resultant findings on the lubricating oil requirement, as well as the accompanying tests.
Ashok J. Keche - One of the best experts on this subject based on the ideXlab platform.
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CONSTANT SPEED ENGINE Conrod SOFT VALIDATION & OPTIMIZATION
2014Co-Authors: D. Dantale, Ashok J. KecheAbstract:The constant speed four stroke reciprocating engine Connecting rod is subjected to variable loading when Engine is in operating condition. Proper optimization of connecting rod is critical for the engine Performance, vibration level & balancing of overall engine. The stresses in Connecting rod are not constant during its operating condition. The stress varies in one complete cycle. The connecting rod traditionally were designed and analyzed under Static axial loading condition. The Quasi-dynamic approach has a considerable effect in design optimization of connecting rod. The finite element analysis of four stroke Diesel engine is considered. Structural systems of connecting rod can be easily analyzed using Finite Element techniques. So firstly a proper a CAD model is developed Pro/E Wildfire 4.0. Then the Finite element analysis is done to determine the Von Mises stresses in the existing connecting rod for the given loading conditions using Finite Element Analysis software ANSYS. The optimization of Conrod is done based on the results and validated.
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constant speed engine Conrod soft validation optimization
2014Co-Authors: D. Dantale, Ashok J. KecheAbstract:The constant speed four stroke reciprocating engine Connecting rod is subjected to variable loading when Engine is in operating condition. Proper optimization of connecting rod is critical for the engine Performance, vibration level & balancing of overall engine. The stresses in Connecting rod are not constant during its operating condition. The stress varies in one complete cycle. The connecting rod traditionally were designed and analyzed under Static axial loading condition. The Quasi-dynamic approach has a considerable effect in design optimization of connecting rod. The finite element analysis of four stroke Diesel engine is considered. Structural systems of connecting rod can be easily analyzed using Finite Element techniques. So firstly a proper a CAD model is developed Pro/E Wildfire 4.0. Then the Finite element analysis is done to determine the Von Mises stresses in the existing connecting rod for the given loading conditions using Finite Element Analysis software ANSYS. The optimization of Conrod is done based on the results and validated.