Oil Transport in the Piston Ring Pack (Part I): Identification and Characterization of the Main Oil Transport Routes and Mechanisms

2D CFD-model of the piston assembly in a diesel engine for the analysis of piston ring dynamics, mass transport and friction

“…The piston changes position between the thrust (TS) and anti-thrust side (ATS) during a work cycle. This changes the gaps between the piston and liner, which then in turn can provoke a local change of the pressures and cause flow in the circumferential directions [38,43]. The piston tilt motion can cause the piston rings to be also moved and tilted axially.…”

“…In [36,37], Tian used the same model to research the dynamic behaviors of piston rings, such as ring flutter and ring collapse, the piston dynamics and their influence on the gas flow, oil transport, friction and wear. In works [38,39], Thirouard and Tian identify and analytically characterize the oil transport mechanisms. Tian and Wong in [40] researched the influences of the piston tilt on the friction, oil transport and lubrication using the oil control ring as an example.…”

“…As implementation of the dynamic mesh in the 3D model of the ringpack is very complex, the ring dynamics could not be taken into account. The focus of the simulation was calculating the oil transport and the blowby over various flow paths and assessing the transport mechanisms [38]. Oliva et.…”

The influence of lubricant degradation on measured piston ring film thickness in a fired gasoline reciprocating engine

“…Initially, LIF was used as a means to achieve film thickness measurements [10, 28,29] but it was clearly seen that the system had the potential to investigate lubricant transport within the ring pack. The common system of shining a laser beam through the liner was criticised [26,36,39] for only providing information at one point and not valuable information about the oil film variation for the entire piston ring -cylinder wall interface, as the capacitance method was capable of doing when transducers were mounted in the ring [23,26]. This led to the introduction of multipoint LIF investigations, whereby multiple LIF probes were used at various positions on the cylinder liner to improve the understanding of the oil film profiles axially and radially around the piston [9,34,40].…”

Development of a new visualization technique using photochromism for transport process of lubricating oil around the engine piston

“…2 A number of experimental studies have thus been conducted to investigate oil transport phenomena around a piston. [1][2][3][4][5][6][7] These experiments typically visualize the oil film between the piston surface and the cylinder using laser-induced fluorescence (LIF). 1,3,4,6 Flow visualization of an oil film using LIF is difficult because the fluorescence lifetime is extremely short.…”