Investigation on the Frictional Performance of Surface Textured Ring-Deformed Liner Conjunction in Internal Combustion Engines

Abstract

In internal combustion engines (ICEs), the frictional performance of ring-liner conjunction (RLC) has drawn special attention because it greatly affects the fuel efficiency of the engines. In recent years, surface texture (i.e., micro dimples or grooves) has emerged as a promising approach to improve the frictional performance of RLC. However, most current studies on surface textured RLC were conducted by assuming that the liner was ideally circular and the lubrication condition was either fully flooded or starved. In this study, to evaluate the frictional characteristics of an RLC with surface texture on the ring, a numerical model of lubrication is presented by considering the liner deformation, as well as the coexistence of the fully flooded and staved lubrication conditions in an engine cycle. On this basis, the frictional properties of a surface textured RLC are analyzed, and the impacts of the liner deformation and temperature on the friction-reducing effect of the surface texture are also evaluated. The results show that the surface texture on the ring can effectively reduce the power dissipation and friction dissipation of an RLC, and the reductions vary with the liner temperature and deformation. Large reductions in the power dissipation and friction dissipation of an RLC are obtained when the liner temperature is low or the liner deformation is small.

Improving frictional performance of ring-liner system under cylinder deactivation conditions by surface texturing

“…u c is an index related to the cavitation, and its value is closely correlated with the lubricant pressure in the surface textured RLS. The relationship between the cavitation index u c and the lubricant pressure p is discussed in detail by Liu et al 38 U is the ring speed, and it can be expressed by:…”

“…The detailed derivation process for the two mass balance equations are provided in our previous work. 38 At the inlet and outlet of lubrication zone, the mass balance equations can be written as follows…”

“…31 The superscript 0 is the parameter at the previous time. S ABCD and S WXYZ are the areas of the control volumes at the inlet and outlet of lubricated zone, and they are given by 38,39…”

“…where E# and A represent the equivalent elastic modulus of the surface textured RLS and the apparent contact area of the asperity, F 2.5 (l) and F 2 (l) represent the statistic functions of asperities height. 38 l represents the ratio of the MOFT, k and b represent the density and mean curvature radius of asperities. Hence, the total friction force and power loss of the textured RLS can be calculated by 33,38…”

Wear assessment model for cylinder liner of internal combustion engine under fuzzy uncertainty

“…According to the references, the friction of piston ring-cylinder liner could account about 50 percent of the total mechanical friction of an internal combustion engine [1][2][3]. In order to obtain the better tribological performance, the scholars are focusing on establishing friction and wear model to investigate the relationship between friction and energy consumption of the ICEs [4][5][6][7][8], and the effect of lubrication on friction of piston rings-cylinder liner was studied [9,10]. To monitor the wear state, some scholars analyzed the wear information of abrasive particles in the oil, and the wear of the ICEs was evaluated [11][12][13][14].…”