Tribological behavior of co-textured cylinder liner-piston ring during running-in

Abstract

The running-in of cylinder liner-piston rings (CLPRs) is the most important process that must be performed before a marine diesel engine can be operated. The quality of running-in directly affects the reliability of a CLPR. The surface texture of a CLPR has been proven to significantly affect its lubrication performance. In this study, the tribological behavior of a CLPR during running-in is investigated. Three types of surface textures are generated on the CLPR via laser processing: dimple texture on piston rings, groove texture on cylinder liners, and co-texture on both sides. Subsequently, a series of tests are performed on a slice tester. A load of 300 N (1.64 MPa) is applied, and two speeds (50 and 100 rpm) are adopted. The CLPR running-in quality is characterized based on three parameters, i.e., the friction coefficient, contact resistance, and wear topography. Experimental results show that, compared with a non-textured surface, the three types of surface textures mentioned above improved the friction performance during running-in. The lubricant supply capacity of the dimple texture on the piston ring, as a mobile oil reservoir, is stronger than that of the groove texture on the cylinder liner serving as a static oil reservoir. By contrast, the wear resistance of the dimple texture, as a movable debris trap on the piston ring, is weaker than that of the groove texture on the cylinder liner, which serves as a static debris trap. It is demonstrated that the co-texture combines the advantages of dimples and groove textures. Compared with non-textured surfaces, the friction coefficient decreased the most at 100 rpm (44.5%), and the contact resistance improved the most at 50 rpm (352.9%). The coupling effect provides the surface with improved running-in quality by optimizing the tribological performance, particularly at the dead center. This study provides guidance for the tribological design and manufacturing of CLPR in marine diesel engines.

Surface Texturing of Cylinder Liners: A Review

“…However, additional surface texturing of the cylinder liner is seldom performed in the motorized industry, because of the increasing cost. Combining the texturing of the piston ring and the cylinder liner is another possibility [ 27 ], however, the cost of machining would be seriously increased. Most likely only high-performance engines have the potential be designed with oil pockets on the cylinder surface.…”

“…Miao et al [ 27 ] compared the effects of the piston ring and the cylinder liner texturing on the tribological performance of the piston ring assembly. The surface of the cylindrical liner contained grooves, while the piston ring contained isolated circular dimples.…”

“…Ezhilmaran et al [ 25 ] and Gu et al [ 26 ] revealed that laser surface texturing of piston rings with circular dimples caused reductions in friction. Miao et al [ 27 ] found that dimples on the piston ring surface are better-accumulated lubricant than grooves on the cylinder liner. The dimpled texture of the piston rings led to a better increase in contact resistance than the grooved texture of the cylinder liners [ 28 ].…”

A Review on Friction Reduction by Laser Textured Surfaces in Internal Combustion Engines

“…While surface texturing has been applied to cylinder walls of internal combustion engines [59,60] or on both the liner and piston rings [61], this paper focuses on the laser surface texturing of piston rings.…”

Experimental Study on Texture Coupling Mechanism and Antifriction Performance of Piston Rod Seal Pair

“…Tang et al [ 38 ] redesigned the crescentiform surface texture and investigated the tribological properties of ethylene propylene diene monomer (EPDM) rubber under different loading conditions, and the results showed that under low loading conditions, the crescentiform surface texture can effectively reduce the friction coefficient of the friction pair and reduce corrosive wear and adhesive wear. Miao et al [ 39 , 40 ] compared the friction performance of cylinder liner and piston ring (metal–metal seal) with single texture and coupling texture. Compared with single texture, the friction performance of coupling texture is better; the surface of the texture is easier to generate a stable oil film, which can enhance the ability to collect abrasive chips to prevent abrasive chips from scratching the surface and play a role in reducing friction.…”