| 1. |
- Dimkovski, Zlate, et al.
(författare)
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Interference Measurements of Deposits on Cylinder Liner Surfaces
- 2011
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Ingår i: Wear. - Amsterdam : Elsevier. - 0043-1648 .- 1873-2577. ; 270:3-4, s. 247-251
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of deposits in the honing grooves of the cylinder liner surfaces of internal combustion engines is undesirable as they seal the grooves (reducing their oil retention capability) and increase engine's oil consumption. As part of a long-term programme of truck engine development, after different running times and under similar conditions of load, engine speed and lubrication, a number of grey iron cylinder liners were axially sectioned, measured, inspected and a presence of deposits was discovered. These deposits were characterised in order to gain knowledge about their origin and quantities. The X-ray energy dispersive analysis revealed elements stemming from the oil/fuel (C, O and S), from the detergent (Ca and Mg), from the anti-wear additive (Zn and P), and from some contaminants (K and Si). Higher concentration of S and Ca were mostly found in the honing grooves covered with deposits suggesting a domination of the detergent additive. Deposit thickness measurements obtained by a white light interferometer revealed patchy deposit topographies concentrated at the top region reducing towards the bottom of the liner which was also confirmed by scanning electron microscope measurements. Despite the limitations of the interferometer, it has been shown that the interference measurements are sufficiently reliable for a quick and objective quantification of the overall deposit accumulation.
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| 2. |
- Flys, Olena, 1971-, et al.
(författare)
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Piston ring topography variation and robust characterization
- 2014
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Konferensbidrag (refereegranskat)abstract
- It is a constant challenge for the automotive industry to reduce friction losses and oil consumption in automobile engine. The piston ring friction accounts for approximately 20% of the total mechanical energy losses in a modern engine. Oil control rings limit and control the oil consumption of the engine as well. They scrape off excess lubricating oil from the cylinder walls and return it to the crank case. Piston rings are designed to distribute the thin oil film evenly to ensure piston and ring lubrication. The surface topography of a piston ring is an efficient variable in the control of the oil consumption and friction losses. In places where the interacting surfaces come in contact, the oil film thickness is extremely thin and the surface asperities may deform because of the high pressures. There are different types of oil control rings.The most common one is the twin land oil control ring, which consists of two narrow lands that scrape off the oil on the liner and a spring on the back that exerts the load. In this paper, the surfaces of the two lands were investigated, since they play the key role in its function. The goal is to map the variation in surface roughness of piston rings that appear at different scales from form and waviness to micro and nano roughness. Areal topography measurements were made by white light interferometer designed at the Halmstad University able to measure and scan the total functional area of a piston ring. An significant amount of oil control piston rings of heavy duty truck engines were examined and 24 measurements were made in circumferential direction and on each ring land. The results show both the variation and uncertainty of the ring topography and discuss the instrument and measuring methodology uncertainty. The most stable parameters were found and recommended for an effective quality control. Comparisons between established coherence scanning interferometer and the instrument built in Halmstad were made. To ensure a good quality, the measurements were made both on calibration standards and on piston ring surfaces. Finally the influence on function and energy losses in the final engine assembly is discussed to indicate future design and metrology improvements.
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| 3. |
- Rosén, Bengt Göran, 1962-, et al.
(författare)
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Analysis of 3-D surfaces in forming dies and sheet metal - Today and tomorrow
- 2004
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Ingår i: Proceedings of the International Conference on Recent Advances in Manufacture and Use of Tools and Dies and Stamping of Steel Sheets. ; , s. 29-53
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Konferensbidrag (refereegranskat)abstract
- The effects of surface roughness on production of steel sheet are critically reviewed. New developments in the measurement and characterisation of surface roughness seem likely to improve our understanding of its effect on sheet metal production. Much useful information can still be acquired by 2D techniques but increasingly the evidence is that sheet metal surface roughness is better measured and characterised by 3D methods. The facility for direct surface visualization in 3D is shown to be particularly helpful. When measuring 3D the measurement area size and sampling space are critical and for evaluation the filtering of surface data into roughness and waviness is more complicated than for 2D profiles.
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| 4. |
- Rosen, Bengt-Göran, 1962, et al.
(författare)
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Topographic modelling of haptic properties of tissue products
- 2014
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Ingår i: Journal of Physics: Conference Series. - Bristol : IOP Publishing. - 1742-6588 .- 1742-6596. ; 483:1
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Konferensbidrag (refereegranskat)abstract
- The way a product or material feels when touched, haptics, has been shown to be a property that plays an important role when consumers determine the quality of products For tissue products in constant touch with the skin, softness becomes a primary quality parameter. In the present work, the relationship between topography and the feeling of the surface has been investigated for commercial tissues with varying degree of texture from the low textured crepe tissue to the highly textured embossed- and air-dried tissue products. A trained sensory panel at was used to grade perceived haptic «roughness». The technique used to characterize the topography was Digital light projection (DLP) technique, By the use of multivariate statistics, strong correlations between perceived roughness and topography were found with predictability of above 90 percent even though highly textured products were included. Characterization was made using areal ISO 25178-2 topography parameters in combination with non-contacting topography measurement. The best prediction ability was obtained when combining haptic properties with the topography parameters auto-correlation length (Sal), peak material volume (Vmp), core roughness depth (Sk) and the maximum height of the surface (Sz). © Published under licence by IOP Publishing Ltd.
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| 5. |
- Rosén, Bengt Göran, et al.
(författare)
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Topographical characterisation of artificial femoral heads : a Benchmarking study
- 2004
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Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 257:12, s. 1275-1280
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Tidskriftsartikel (refereegranskat)abstract
- The main functional demands on artificial joints are that they last more than 20 years. This means optimising the friction coefficient to minimise forces transmitted to the surrounding bone and the wear of the contacting surfaces. Surface roughness has an important influence on friction and wear. Traditionally, the 2D Ra-parameter has been the preferred way to characterise the joint's topography. Today ongoing development of 3D techniques are available for the research, and the aim of the present paper is to highlight the importance and possibilities using high-resolution 3D atomic force microscope ( AFM) and the optical phase-shifting interferometer for texture characterisation of eight commercially available femoral heads. The results show a significant variation of topography and surface-lay for the different femoral heads in the study. The variation and difference between heads were further underlined by the use of different characterisation techniques and measuring strategy. Results highlight the importance of the selection of measurement strategy, parameters, instrumentation, and scale of measurement in order properly to characterise the femoral heads in this study.
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| 6. |
- Rosén, Stefan, et al.
(författare)
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The Stedman diagram revisited
- 2014
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Ingår i: Surface Topography : Metrology and Properties. - Bristol : Institute of Physics (IOP). - 2051-672X. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- The Stedman diagram has been used for some years to display aspects of the performance of instruments measuring surface roughness. Such diagrams are herein employed to compare the features of a range of proprietary measuring instruments, including contact and non-contact devices. An extension of the basic diagram is proposed, which would allow it to include a further aspect: the speed of data collection. Figures of merit based on the revised diagram are computed, which enable instruments to be ranked on these particular aspects of their performance. Contact instruments emerge as comparable to non-contact, as their slower rate of data acquisition can be offset by the greater area they can access in amplitude–wavelength space. © 2014 IOP Publishing Ltd.
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| 7. |
- Rosén, Stefan, et al.
(författare)
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The Stedman diagram revisited
- 2013
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Ingår i: Metrology and Properties of Engineering Surfaces, 2013. ; , s. 201-206
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Konferensbidrag (refereegranskat)abstract
- The Stedman diagram has been used for some years to display aspects of the performance of surface roughness measuring instruments. Such diagrams are herein employed to compare the features of a range of proprietary measuring instruments, including contact and non-contact devices. An extension of the basic diagram is proposed which would allow it to include a further aspect, speed of data collection. Figures of merit based on the revised diagram are computed which enable instruments to be ranked on these particular aspects of their performance. Contact instruments emerge as comparable to non-contact, as their slower rate of data acquisition can be offset by the greater area they can access in amplitude-wavelength space.
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| 8. |
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| 9. |
- Anderberg, Cecilia, et al.
(författare)
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Alternative descriptions of roughness for cylinder liner production
- 2009
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Ingår i: Journal of Materials Processing Technology. - Amsterdam : Elsevier. - 0924-0136 .- 1873-4774. ; 209:4, s. 1936-1942
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Tidskriftsartikel (refereegranskat)abstract
- The roughness of stratified surfaces such as cylinder liners, produced by plateau honing, is functionally important in their tribology but is notoriously difficult to characterise. An issue in manufacturing quality control related to their tribological function is the comparative ability of various roughness characterisation systems. In this paper the Rk family of parameters is compared with the Rq family as regards stability and discrimination. When coefficients of variation of the two parameter families are compared as a measure of stability, CVs of individual parameters vary between 8% and 20% but do not seem to indicate a clear advantage to either family. When the correlation of parameters within and between the two groups is computed as a measure of relative discriminative ability, many parameters are found to be highly correlated, to the point where values of Rpk and Rpq are effectively indistinguishable. The relative robustness of the parameters is also established by simulation of surface or measurement artefacts: outlying peaks and valleys, high-frequency noise, changes in stylus or skid radius, changes in high-pass filter and in assessment length. Outlying peaks cause a large increase in Rpk, while outlying valleys have little effect. The Rq parameters are more sensitive to high-frequency noise than the Rk parameters. Increasing the stylus radius reduced the valley parameters, while adding a 25 mm radius skid increased Rk and Rpq by as much as 15%. Increasing the short-wavelength cut-off from 2.5 m to 8 m reduced most parameters, particularly the peak parameters, while replacing the robust Gaussian filter used throughout by a valley-suppression filter had little effect. Finally reducing the assessment length from 17 mm to 4 mm decreased the values of many parameters by up to 11%. Increasing plateau honing time decreased plateau roughness, while increasing pressure during coarse honing increased valley roughness, but these changes could not be correlated with roughness parameters. This suggests that the optimum parameter set has not yet been found. 2008 Elsevier B.V. All rights reserved.
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| 10. |
- Anderberg, Cecilia, et al.
(författare)
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Combined SEM and Stylus Profiling Sensoring for Improved Cylinder Liner Honing
- 2006
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Ingår i: Proceedings of Austrib 06 - International Tribology Conference. - Brisbane : Queensland University of Technology. ; , s. 6-
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Konferensbidrag (refereegranskat)abstract
- The demands on decreased environmental impact from vehicles are resulting in a strong push for decreased engine oil and fuel consumption.Recent engine tests have shown a promising reduction in oil consumption when using cylinder liners with a smoother finish than the current plateau honing.One approach to produce smoother liner surfaces is to replace SiC ceramic honing stones with diamond tools. However, even though the diamond honing process results in higher productivity, improved quality control is needed to monitor the degree of cold worked material - “blechmantel” (German), and the resulting risk of increased wear and scuffing.A number of petrol and diesel engine cylinder liners have been mapped to be able to verify the quality and consequences, in terms of wear and function, of the honing process. A new mapping method, combining SEM images and quantitative image analysis with traditional 2D profilometry has been developed and tested in this study. The surface mapping method developed was employed before and after the test to study effect of running-in wear on the surface, features characterized with the SEM- and the 2D profilometer.The results show that combining SEM- and profilometric methods gives a good picture of the effects of varying the cylinder liner pressure and roughness. The core roughness decreases more for diesel liners than for petrol liners.. A probable cause is that the more severe diesel high pressure run-in conditions are able to effectively “truncate” the plateaux and remove residing plastically deformed un-cut honing residues while the less severe petrol liner conditions do not manage to remove the blechmantel and irregularities to an important extent.
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