ISSN -
2nd International Brazilian Conference on Tribology — vol. 2, num.2 (2014)
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Abstract
Lubricant oils are subjected to reciprocating movement in the piston ring/cylinder tribocouple of automotive engines. In this kind of movement, the relative speed oscillates between zero and a maximum, and therefore the lubrication regime goes from boundary to hydrodynamic. Tribotests are widely used in laboratories to hint at the friction developed in these systems. In the present work, a SRV tribometer was used to evaluate the friction behaviour of lubricant oils under reciprocating movement up to 60 Hz. A high acquisition rate allowed the analysis of data inside each reciprocating cycle. Both a pure base oil and a fully formulated lubricant were used. Changes in the contact pressure, viscosity and speed were seen to influence friction, which was correlated to the relative thickness predicted by Hamrock-Dowson equation. While some observed characteristics were typical consequences of the Stribeck curve, other effects were also observed, such as the occurrence of seizure at high reciprocating frequency. A lower boundary coefficient of friction due to additive package in the formulated oil was also observed. The results allow a better understanding of friction in reciprocating cycles and can be used to evaluate the performance of oils and surfaces in laboratory prior to engine testing.
Keywords
Friction; Lubricant; Tribometer; SRV; Stribeck
How to refer
Eduardo Dominguez Trindade;
Amilton Sinatora.
FRICTION BEHAVIOUR AND THE STRIBECK CURVE IN RECIPROCATING CYCLES
,
p. 4106-4115.
In: 2nd International Brazilian Conference on Tribology,
Foz do Iguaçu - Brasil,
2014.
ISSN: -
, DOI 10.5151/1472-5836-25758