Piston ring wear and cylinder liner tribofilm in tribotests with lubricants artificially altered with ethanol combustion products

Numerical analysis of the effects of compression ring wear and cylinder liner deformation on the thermal mixed lubrication performance of ring-liner system

“…where R is the radius of crankshaft, v is the angular velocity of crankshaft, l is the length of connecting rod. In ICEs, the face profile of compression ring is usually asymmetrical in the axial direction [20,21], and the wear of compression ring is inevitable because of serious solid-solid contact caused by the high cylinder pressure and temperature [30,31]. In this study, in order to investigate the influence of compression ring wear on the lubrication performance of CRCL, the asymmetrical compression rings in various wear degrees or after various service time (i.e., the un-wear compression ring (new compression ring), run-in compression ring, and embedded compression ring) are considered.…”

Nano and microscale contact characteristics of tribofilms derived from fully formulated engine oil

“…One is the pressure coefficient of boundary shear strength, and the other is the reduced (effective) elastic modulus of the contacting surfaces, * ; taking into account the effect of any tribo-film present. This makes a significant difference to the accuracy of predicted boundary friction [30] as it affects the calculated asperity load carrying capacity through equation (9).…”

“…However, at piston reversals, lubricant entrainment ceases momentarily and direct interaction of rough contiguous surfaces occurs. The role of surface-active lubricant additives and the tribofilm formation is critical in controlling friction and wear [9]. The synergistic and antagonistic behaviour of additive species at the contacting surfaces is determined through the competitive process of tribofilm formation [10,11].…”

Tribological behaviors of internal plasma sprayed TiO 2 -based ceramic coating on engine cylinder under lubricated conditions

“…The COF was recorded automatically throughout the experiments. The significant index of the wear degree is not the wear volume, but the average wear depth, which is closely related to the fuel consumption of the engines [5,8,25]. …”

“…Particularly, most laboratory experiments of the tribosystem were conducted under the condition of starved/ boundary lubrication [7][8][9][10][11]. The researchers consider that severe contact wear between cylinder bore and piston ring is expected to occur mainly in the top dead center (TDC) position of the piston stroke where high load, low speed, high temperature and adverse environments occur.…”