Use este identificador para citar ou linkar para este item: http://repositorio.utfpr.edu.br/jspui/handle/1/32953
Título: Energetic coefficient of friction applied to cylinder liners lab tests
Autor(es): Vale, João Luiz do
Silva, Carlos Henrique da
Pintaúde, Giuseppe
Palavras-chave: Motores - Lubrificação
Atrito
Força (Mecânica)
Tribologia
Motors - Lubrification
Friction
Power (Mechanics)
Tribology
Data do documento: 30-Nov-2019
Câmpus: Curitiba
Citação: VALE, João Luiz do; SILVA, Carlos Henrique da; PINTAÚDE, Giuseppe. Energetic coefficient of friction applied tocylinder liners lab tests. Industrial Lubrication and Tribology, London, v. 72, n. 9, p. 1103-1108, nov. 2020. DOI: https://doi.org/10.1108/ILT-08-2019-0324. Disponível em: https://www.emerald.com/insight/content/doi/10.1108/ILT-08-2019-0324/full/html.
Abstract: Purpose - This paper aims to present a proposal for evaluating the coefficient of friction (COF), under a reciprocating test that considers the energy dissipated by the friction force. In addition, this new parameter is compared to average COF, which is often used to evaluate COF in reciprocating tests. Design/methodology/approach - Samples of compacted graphite iron were extracted directly from an internal combustion engine block. The piston ring used was a nitrided martensitic stainless steel with an asymmetrical profile, and the lubricant oil was the SAE 30 CF, controlled at 40°C. Different testing conditions were carried out in a CETR-UMT-Bruker tribometer, varying loads between 25-125 N, frequencies between 1-12.5 Hz and track length between 3-10 mm. Three maps comparing the average COF and the energetic definition were built, allowing to discuss their similarities. Findings - In general, both parameters had similarities especially for low frequencies and small tracks. However, for test conditions that imposed higher accelerations (i.e. longer track lengths and higher frequencies), the energetic COF (COFe) was lower than the average COF (COFa) and presented better agreement in Stribeck-like curves – independent on the experienced lubrication regime along the stroke. As the COFe can be interpreted as a weighted average of instantaneous COF in relation to in-track displacements, an immediate consequence is that instantaneous COF closest to mid-stroke is considered more significant. Furthermore, perturbations associated with the intrinsic accelerations of the movement test are minimized in the COFe formulation. Originality/value – The energetic COF parameter (COFe) is presented and compared to the average COF. The new parameter presented less data dispersion and is attractive to evaluate the COF behavior in reciprocating tests, as its formulation minimizes perturbations associated with the intrinsic accelerations of the movement (mainly in the initial and final part of the track where the acceleration has its greatest magnitude).
URI: http://repositorio.utfpr.edu.br/jspui/handle/1/32953
ISSN: 0036 8792
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