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John, S., El-Ghoul, Z., Dimkovski, Z., Lööf, P.-J., Lundmark, J. & Mohlin, J. (2019). Friction between pin and roller of a truck's valvetrain. Surface Topography: Metrology and Properties, 7(1), Article ID 014001.
Open this publication in new window or tab >>Friction between pin and roller of a truck's valvetrain
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2019 (English)In: Surface Topography: Metrology and Properties, E-ISSN 2051-672X, Vol. 7, no 1, article id 014001Article in journal (Refereed) Published
Abstract [en]

In order to minimize the fuel consumption in internal combustion engines, the frictional losses must be minimized between the moving parts such as the sliding bearings. In this study, the sliding friction between the pin and roller in a heavy duty truck engine's valvetrain has been investigated. Three combinations of production components with different surface treatment were used: steel pin with steel roller, steel pin with WS2 coating inside the roller and PVD coated steel pin with steel roller. In-house test rig was used, enabling controlled conditions close to the real engine. A new method for alignment using a laser scanner was introduced together with high resolution tactile measurements of radial displacement during test. Surface topography of pins and rollers was measured before test with a mechanical stylus instrument. The WS2 showed 3.1 times and the PVD showed 2.5 times lower friction than the steel type at low speeds. Even though the friction reduction of WS2 over the PVD is not large, the important advantage is that the WS2 can be manufactured at lower costs than the PVD one. Good correlations among the friction, initial roughness and radial displacements were also found.

Place, publisher, year, edition, pages
Bristol: Institute of Physics Publishing (IOPP), 2019
Keywords
tribology, WS2 coating, PVD coating, surface roughness, topography, friction, valvetrain
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:hh:diva-38760 (URN)10.1088/2051-672X/aafe47 (DOI)000459745900001 ()
Funder
Vinnova
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-03-22Bibliographically approved
Anderberg, C., Dimkovski, Z., Rosén, B. G. & Thomas, T. R. (2019). Low friction and emission cylinder liner surfaces and the influence of surface topography and scale. Tribology International, 133, 224-229
Open this publication in new window or tab >>Low friction and emission cylinder liner surfaces and the influence of surface topography and scale
2019 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 133, p. 224-229Article in journal (Refereed) Published
Abstract [en]

A low friction piston ring pack, with tangential load halved, was tested in engines with four different cylinder liner finishes. Oil consumption, oil temperature and liner surface temperature were monitored at different load and speed levels, under similar test conditions. The two smoother surfaces generally kept lower oil consumption compared to the two rougher ones. Results were correlated using an area-fractal analysis. The relative area of the surface was calculated at different scales and the result was compared with the level of oil consumption for the different liner surfaces at different engine speeds. It was found that oil consumption was strongly correlated with scale for areas of above 1000 μm2 and below 20 μm2.

Place, publisher, year, edition, pages
Kidlington: Pergamon Press, 2019
Keywords
Cylinder liners, Oil consumption, Roughness, Fractal analysis
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:hh:diva-38859 (URN)10.1016/j.triboint.2018.11.022 (DOI)2-s2.0-85060228503 (Scopus ID)
Funder
VINNOVA
Available from: 2019-02-07 Created: 2019-02-07 Last updated: 2019-02-08
Dimkovski, Z., Lööf, P.-J., Rosén, B. G. & Nilsson, P. (2018). Functional parameter screening for predicting durability of rolling sliding contacts with different surface finishes. Surface Topography: Metrology and Properties, 6(2), Article ID 024005.
Open this publication in new window or tab >>Functional parameter screening for predicting durability of rolling sliding contacts with different surface finishes
2018 (English)In: Surface Topography: Metrology and Properties, ISSN 2051-672X, Vol. 6, no 2, article id 024005Article in journal (Refereed) Published
Abstract [en]

The reliability and lifetime of machine elements such as gears and rolling bearings depend on their wear and fatigue resistance. In order to screen the wear and surface damage, three finishing processes: (i) brushing, (ii) manganese phosphating and (iii) shot peening were applied on three disc pairs and long-term tested on a twin-disc tribometer. In this paper, the elastic contact of the disc surfaces (measured after only few revolutions) was simulated and a number of functional and roughness parameters were correlated. The functional parameters consisted of subsurface stresses at different depths and a new parameter called 'pressure spikes' factor'. The new parameter is derived from the pressure distribution and takes into account the proximity and magnitude of the pressure spikes. Strong correlations were found among the pressure spikes' factor and surface peak/height parameters. The orthogonal shear stresses and Von Mises stresses at the shallowest depths under the surface have shown the highest correlations but no good correlations were found when the statistics of the whole stress fields was analyzed. The use of the new parameter offers a fast way to screen the durability of the contacting surfaces operating at similar conditions. © 2018 IOP Publishing Ltd.

Place, publisher, year, edition, pages
Bristol: Institute of Physics Publishing (IOPP), 2018
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:hh:diva-37817 (URN)10.1088/2051-672X/aabd71 (DOI)000431455700001 ()2-s2.0-85051420390 (Scopus ID)
Funder
VINNOVA
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-08-29Bibliographically approved
Dimkovski, Z., Tomanik, E., Grange, S. & Epinat, F. (2018). Novel testing methods for screening the tribological performance of ring-liner surfaces. Surface Topography: Metrology and Properties, 6(3), Article ID 034017.
Open this publication in new window or tab >>Novel testing methods for screening the tribological performance of ring-liner surfaces
2018 (English)In: Surface Topography: Metrology and Properties, E-ISSN 2051-672X, Vol. 6, no 3, article id 034017Article in journal (Refereed) Published
Abstract [en]

The piston system accounts for about the half of the frictional losses of internal combustion engines and requires special testing methods to understand and improve its function. The most common way to screen the surface performance is to rub ring/liner segments against each other in a reciprocating manner. However, short reciprocating tests have intrinsic low sliding speeds, unable to reach the mixed/hydrodynamic regimes found in the engine, especially at the mid-stroke. This paper presents a rotating test for the oil control ring, which has the largest frictional losses of all other rings. Both reciprocating and rotating tests were conducted using different in-house developed modules and fixtures. Twin land oil control rings against liners with two different finishes commonly used in heavy duty diesel truck engines were tested under similar loads and speeds as in a real engine. Engine oil 5W-30 and room temperature was used for all the tests. Sliding speed, load, friction force and electrical resistance were recorded during the tests. The results show a clear discrimination of the different liner finishes depending on the lubrication regime present.

Place, publisher, year, edition, pages
Bristol: Institute of Physics Publishing (IOPP), 2018
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:hh:diva-37819 (URN)10.1088/2051-672X/aad408 (DOI)000441147700002 ()
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-08-29Bibliographically approved
Cabanettes, F., Joubert, A., Chardon, G., Dumas, V., Rech, J., Grosjean, C. & Dimkovski, Z. (2018). Topography of as built surfaces generated in metal additive manufacturing: A multi scale analysis from form to roughness. Precision engineering, 52, 249-265
Open this publication in new window or tab >>Topography of as built surfaces generated in metal additive manufacturing: A multi scale analysis from form to roughness
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2018 (English)In: Precision engineering, ISSN 0141-6359, E-ISSN 1873-2372, Vol. 52, p. 249-265Article in journal (Refereed) Published
Abstract [en]

Topographies are one of the challenges for the development of the metal additive manufacturing promising technique. The article investigates multi scale topographies (from form to roughness) of as built surfaces generated by selective laser melting (SLM). Different building inclinations of samples were observed both for upskin and downskin surfaces with a wide range of measuring techniques. The two main aims are: (i) to make a critical review of measuring techniques at different scales, (ii) to enlighten the different surface generation phenomena (and the corresponding scale) occurring during additive manufacturing. The effect of heat treatment on each scale of the topography is also discussed. It is found that the focus variation technique is well suited for AM surfaces. Concerning the observation of the inclined surfaces, some parameters are emphasized as good indicators of typical signatures of AM surfaces: isotropy for the weld track component, the skewness and Rsm for the staircase effect, fractal dimension for the presence of partly melted particles. The different parameters studied helps to model and understand the different surface generation phenomena aforementioned. © 2018 Elsevier Inc.

Place, publisher, year, edition, pages
Philadelphia, PA: Elsevier, 2018
Keywords
3D topography characterization, As built surfaces, Form, Metal additive manufacturing, Multi scale measurements, Roughness, Selective laser melting, Staircase effect
National Category
Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:hh:diva-37820 (URN)10.1016/j.precisioneng.2018.01.002 (DOI)000435620800024 ()2-s2.0-85040718309 (Scopus ID)
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-08-29Bibliographically approved
John, S., El-Ghoul, Z.-F., Dimkovski, Z., Lööf, P.-J., Lundmark, J. & Mohlin, J. (2017). Friction between Pin and Roller of a Truck’s Valvetrain. In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts. Paper presented at 16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017 (pp. 193-194).
Open this publication in new window or tab >>Friction between Pin and Roller of a Truck’s Valvetrain
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2017 (English)In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts, 2017, p. 193-194Conference paper, Oral presentation with published abstract (Refereed)
Keywords
Tribology, Surface roughness, DLC, WS2
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:hh:diva-35002 (URN)
Conference
16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017
Available from: 2017-09-18 Created: 2017-09-18 Last updated: 2018-01-13Bibliographically approved
Dimkovski, Z., Lööf, P.-J., Dumbreville, L., Rosén, B. G. & Nilsson, P. (2017). Functional Parameters Screening for Predicting Wear between Two Cylindrical Surfaces with Different Finishes. In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts. Paper presented at 16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017 (pp. 75-76).
Open this publication in new window or tab >>Functional Parameters Screening for Predicting Wear between Two Cylindrical Surfaces with Different Finishes
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2017 (English)In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts, 2017, p. 75-76Conference paper, Oral presentation with published abstract (Refereed)
Keywords
tribology, rough contact simulations, twin-disc tests
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:hh:diva-34985 (URN)
Conference
16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017
Available from: 2017-09-15 Created: 2017-09-15 Last updated: 2018-01-13Bibliographically approved
Cabanettes, F., Faverjon, P., Sova, A., Dumont, F., Rech, J. & Dimkovski, Z. (2017). Influence of surface topography on starvation of lubricated contacts: application to MQL machining. In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts. Paper presented at 16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017 (pp. 187-189).
Open this publication in new window or tab >>Influence of surface topography on starvation of lubricated contacts: application to MQL machining
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2017 (English)In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts, 2017, p. 187-189Conference paper, Oral presentation with published abstract (Refereed)
Keywords
surface topography, starvation, Minimum Quantity Lubrication, machining, mist droplet size distribution
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:hh:diva-35001 (URN)
Conference
16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017
Available from: 2017-09-18 Created: 2017-09-18 Last updated: 2018-03-23Bibliographically approved
Lööf, P.-J., Dimkovski, Z., Rosén, B. G. & Nilsson, P. (2017). Measuring Technique for Characterization of Micropitting. In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts. Paper presented at 16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017 (pp. 185-186).
Open this publication in new window or tab >>Measuring Technique for Characterization of Micropitting
2017 (English)In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts, 2017, p. 185-186Conference paper, Oral presentation with published abstract (Refereed)
Keywords
surface finish, tribology, micropitting, gearbox tests
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:hh:diva-35000 (URN)
Conference
16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017
Available from: 2017-09-18 Created: 2017-09-18 Last updated: 2017-09-22Bibliographically approved
Cabanettes, F., Joubert, A., Rech, J. & Dimkovski, Z. (2017). Multi scale analysis of as built surfaces generated in metal additive manufacturing. In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts. Paper presented at 16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017 (pp. 149-150).
Open this publication in new window or tab >>Multi scale analysis of as built surfaces generated in metal additive manufacturing
2017 (English)In: Mets&Props 2017: 16th International Conference on Metrology and Properties of Engineering Surfaces: Conference abstracts, 2017, p. 149-150Conference paper, Oral presentation with published abstract (Refereed)
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:hh:diva-34986 (URN)
Conference
16th International Conference on Metrology and Properties of Engineering Surfaces, Gothenburg, Sweden, June 27-29, 2017
Available from: 2017-09-15 Created: 2017-09-15 Last updated: 2017-09-22Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3149-4296

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