Comparative Experimental Study of Tribo-Mechanical Performance of Low-Temperature PVD Based TiN Coated PRCL Systems for Diesel Engine

Abstract

Piston ring and cylinder liner (PRCL) interface is a major contributor to the overall frictional and wear losses in an IC engine. Physical vapor deposition (PVD) based ceramic coatings on liners and rings are being investigated to address these issues. High temperature requirements for applications of conventional coating systems compromise the mechanical properties of the substrate materials. In the current study, experimental investigation of tribo-mechanical properties is conducted for various titanium nitride (TiN) coated PRCL interfaces in comparison with a commercial PRCL system. Low-temperature PVD based TiN coating is successfully achieved on the grey cast iron cylinder liner samples. Surface roughness of the grey cast iron cylinder liner substrates and the thickness of TiN coating are varied. A comprehensive comparative analysis of various PRCL interfaces is presented and all the trade-offs between various mechanical and tribological performance parameters are summarized. Coating thickness between 5 and 6 micrometres reports best tribo-mechanical behaviour. Adhesion and hardness are found to be superior for the TiN coatings deposited on cylinder liner samples with higher roughness, i.e., ~ 5-micron Ra. Maximum 62 % savings on the COF is reported for a particular PRCL system. Maximum 97% saving in cylinder liner wear rate is reported for another PRCL system.

Piston Ring Material in a Two-Stroke Engine Which Sustains Wear Due to Catalyst Fines

“…Traditionally, it is considered that wear resistance of the coatings just depends on the hardness but nevertheless, elastic modulus also plays a vital contribution in the wear characteristics. [28]. The modulus of elasticity of the G17 piston ring is 110-140 GPa [29], whereas the modulus of elasticity at the complex chromium alloyed grey iron is 154-196 GPa according to DIN 1695 [27].…”

Development and tribo-mechanical properties of functional ternary nitride coatings: Applications-based comprehensive review

“…It has been reported that even binary coatings like TiN can mitigate the fuel and energy consumption by applying it to the sliding parts of the engine. 310 Therefore, it would be useful to apply other ternary coatings like TiAlN, TiCN, TiSiN, TiCuN, TiMoN, TiCrN, TiZrN, and TiBN on the cylinder liner, piston rings, bearings, gears, and other mechanical components in order to enhance the performance and life of these components, used in automotive and aerospace industry.…”