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- Gondal, A. K., et al.
(författare)
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Studies on tribological behaviour of two oil soluble molybdenum compounds under reciprocating sliding conditions
- 1993
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Ingår i: Lubrication Science. - : Wiley. - 0954-0075 .- 1557-6833. ; 5:4, s. 337-359
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Tidskriftsartikel (refereegranskat)abstract
- The use of oil-soluble organo-molybdenum compounds in engine oils can help in fuel conservation by reducing engine friction and increase durability by improving wear characteristics. The tribological behaviour of molybdenum dialkyldithiophosphate (MoDDP) was studied with a SRV Optimol tester under reciprocating sliding conditions. The studies were conducted under nonconformal contact conditions on En-31 steel and conformal contact conditions on piston ring and liner materials. The results indicated that the frictional behaviour of these additives is shear sensitive. Shear sensitivity is influenced by materials, operating conditions and the interaction of MoDDP with additives present in the oil. MoDDP when used in base oil was found to increase the scuff resistance of ring and liner materials. The use of the additive reduced friction and wear (running in as well as normal) under nonconformal contact conditions, while under conformal contact conditions its effect was selective and limited.
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| 4. |
- Kumar, Rajesh, et al.
(författare)
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A systematic methodology to characterise the running-in and steady-state wear processes
- 2002
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Ingår i: Wear. - 0043-1648 .- 1873-2577. ; 252:5-6, s. 445-453
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Tidskriftsartikel (refereegranskat)abstract
- An improved methodology has been developed to characterise running-in and steady-state wear processes. The experimental study was conducted with En 31 steel specimens on reciprocating tester with ball-on-flat geometry under lubricated sliding conditions. The tests were conducted according to a factorial design. The variables selected were the load, temperature and surface roughness. The wear behaviour for a given set of operating conditions has been characterised on the basis of developed methodology. The parametric influence of operating conditions was then analysed on the basis of polynomial relationships. The steady-state wear was found to be significantly influenced by the initial roughness.
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| 5. |
- Kumar, Rajesh, et al.
(författare)
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Assessment of engine liner wear from bearing area curves
- 2000
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Ingår i: Wear. - 0043-1648 .- 1873-2577. ; 239:2, s. 282-286
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a new procedure to evaluate engine liner wear volume and wear depth particularly for short duration engine tests. The method is based on the fact that honing depth is not removed when small amount of wear occurs. It was considered that 90% point of the bearing area curve is the same before and after wear. Then, the bearing area curve for the used liner was transformed by the depth differences at 90% and the area between the two curves was calculated by numerical procedure. As the diameter of the liner is known, the wear volume was calculated for the various zones selected at different points from TDC and BDC. The methodology involved has been programmed in C++. The wear depth is obtained by the projection on the depth axis of the two bearing area curves, and then finding their difference. This method is considered superior to the usual method of gauging the changes in diameter as such determinations are influenced by the distortions that occur in the liner. The new procedure needs to be applied more extensively to improve confidence in repeatability and reproducibility and to determine the limits of applicability. Controlled laboratory wear tests and further measurements on cylinders from field engines are therefore proposed.
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| 8. |
- Sethuramiah, A., et al.
(författare)
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Lubricated wear of PTFE and graphited PTFE
- 1991
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Ingår i: Lubrication Science. - : Wiley. - 0954-0075 .- 1557-6833. ; 3:3, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- Tribological behaviour of PTFE and graphited PTFE have been evaluated under lubricated conditions and compared with dry wear. The stress selected is in the range of 0.44 to 1.64 MPa, and the data generated are relevant to conformal contacts. Mineral oil lubrication can reduce wear of PTFE by one to two orders of magnitude. With graphited PTFE the lubricant effect is lower in comparison to that observed with PTFE. Specific wear rates are plotted on a histogram.
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