Simulated fuel dilution and friction-modifier effects on piston ring friction

Abstract

Government legislation, customer requirement, and pressure from the original equipment manufacturers (OEM) continually pushes the issue of increased vehicle fuel economy to the forefront. Lubricant manufacturers responded by creating low viscosity lubricants with complex additive packages capable of reducing total engine friction while maintaining the useful life of the engine. An important component in the lubricant additive package is the friction modifier, whose job is to reduce the sliding friction of components operating in the boundary lubrication regime.It is widely agreed that 40 -60 per cent of mechanical friction can be attributed to the piston/ ring/cylinder wall interface, much of which is as a result of the compression ring whose lubrication is kept purposely minimal to control exhaust emissions. A logical progression to research suggests utilizing fuel to administer friction modifier directly to the top ring zone of the engine, the area where its effects are most beneficial. This article describes a series of tests conducted using a Plint TE-77 reciprocating tribometer to investigate the synergy of lubricant and fuel containing friction modifier at the top ring zone. A computational model has been modified and utilized to further investigate the potential impact of administering friction modifier at the top ring zone via the fuel.

Frictional response of fatty acids on steel

“…4 shows the coefficient of friction of the stearic acid dispersed oil to decrease with time initially (up to 400 s) and then to stabilized to a time invariant value of 0.09. The recorded value of coefficient of friction matches well with those reported in literature [11]. The coefficient of friction corresponding to the linoleic acid dispersed in oil decreases steadily with sliding time till (4000 s) it appears to reach a steady average value of about 0.04.…”

“…Adhvaryu et al [19] based on their study of multicomponent biobased lubricants also observed that increasing unsaturation lowers the ability of the molecules to be chemisorbed. The work of Smith et al [11] using a reciprocating tribometer however showed that the effect of unsaturation at low loads and temperatures is marginal while at higher loads and temperatures unsaturation reduces friction substantially.…”

“…This has been observed when the acid molecules are adsorbed from being dispersed in oil [11] as well as when they are self-assembled on metallic substrates [7][8][9][10]. This phenomenon has been exploited to design friction modifiers for engine lubrication [11], lubrication of microelectro mechanical system and mechanisms [12,13], to improve the dispersion capabilities of functionalized carbon nanotubes in solvent and composites [14] and lubrication of information storage * Corresponding author. Fax: +91 80 2293 2963.…”

Effect of a Fatty Acid Additive on the Kinetic Friction and Stiction of Confined Liquid Lubricants

“…In addition, approximately 30 % reduction of kinetic friction was achieved by the addition of PA ( Figure S3). These additive effects for macroscopic rough surfaces are compatible with previous studies [8,9,[40][41][42] and are very different from our SFA results. We believe this is reasonable mainly because of the following reason.…”

Tribometer Investigation of the Frictional Response of Piston Rings when Lubricated with the Separated Phases of Lubricant Contaminated with the Gasoline Engine Biofuel Ethanol and Water

“…It can record instantaneous friction force and electrical contact potential, with the limits 0 and 50 mV indicating metal-on-metal contact and complete contact separation, respectively, based on the well established contact potential method of Furey [19]. This TE77 had been previously modified [20] so that lubrication can be provided from one of two sumps which can be switched during testing as shown in Fig. 1.…”