How Piston Ring Coatings Impact Fuel Efficiency in Modern Marine Engines

Fuel Efficiency: A Top Priority for Maritime Operators

In the global shipping industry, fuel accounts for over 50% of a vessel’s operating costs , making energy efficiency a top priority for shipowners and operators. As environmental regulations tighten and fuel prices remain volatile, improving engine performance has become a critical pathway to reducing both emissions and operational expenses.

While propulsion upgrades and alternative fuels draw significant attention, one often-overlooked component plays a decisive role in fuel economy: the marine piston ring. Specifically, the quality of its surface coating can directly influence how efficiently an engine runs.

 The Impact of Piston Rings on Engine Efficiency

A marine piston ring performs multiple essential functions in both 2-stroke and 4-stroke marine engines:

• Seals the combustion chamber, maintaining compression pressure and preventing gas blow-by.
• Transfers heat from the piston to the cylinder liner, supporting thermal regulation.
• Scrapes and redistributes lubricating oil, preventing oil from entering the combustion chamber and contributing to harmful emissions.

When piston rings begin to wear, due to inadequate lubrication, friction, or thermal stress, they can no longer maintain an effective seal. This leads to blow-by, where combustion gases escape into the crankcase, reducing engine efficiency and power output. At the same time, increased metal-to-metal friction raises fuel consumption and accelerates component degradation.

Friction’s Significant Effect on Fuel Consumption

According to industry studies, the piston assembly, including rings and skirt, contributes up to 40–50% of total engine friction. Even a small reduction in this friction can produce meaningful gains in fuel efficiency. That’s why the surface treatment of piston rings has emerged as a key lever in optimising engine performance.

Conventional Coatings and Modern Marine Engines

Conventional coating methods, such as hard chrome plating, nickel, or thermal spray cermet coatings, were historically effective in reducing wear. However, they offer limited friction reduction and can degrade under the thermal and mechanical stress of modern high-load marine operations.

Modern marine engines operate under stricter environmental conditions and performance expectations. International Maritime Organization (IMO) regulations, such as the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII), as well as the introduction of the global shipping carbon pricing mechanisms to meet its 2050 Net-zero GHG emissions targets, are driving the shift toward fuel-saving technologies and lower emissions.

This new regulatory landscape makes it increasingly important to enhance sealing and reduce friction at the component level—particularly in parts that experience the most wear, such as marine piston rings.

NTI Nanofilm’s  i-TAC^® Coating for Fuel Savings

NTI Nanofilm’s i-TAC® is an advanced hydrogen-free DLC (ta-C) coating applied using Filtered Cathodic Vacuum Arc (FCVA) technology. Originally developed to meet the demands of automotive powertrains, i-TAC® has been widely adopted across high-performance piston ring applications, proven to withstand extreme pressure, high temperatures, and aggressive oil chemistries.

Backed by over 20 years of experience in automotive piston ring coatings, NTI Nanofilm is recognised as one of China’s leading suppliers in this field. Leveraging this deep expertise, we now bring the same high-performance coating technology to the marine sector, where piston rings face equally harsh conditions and increasing efficiency requirements.

i-TAC® offers:

• 28% lower friction compared to standard PVD-DLC coatings
• 2.7× higher hardness for superior wear resistance
• 600°C thermal stability
• Excellent oil compatibility and long-lasting seal integrity

By significantly reducing friction between the piston ring and cylinder liner, i-TAC^® enhances fuel efficiency, extends service intervals, and helps operators meet tightening IMO regulations. It is ideal for both 2-stroke and 4-stroke marine engines, delivering consistent performance under demanding operational conditions.

Achieve Future-Ready Efficiency for Your Vessel Fleet

In an industry where marginal gains translate into substantial cost savings, advanced coatings like i-TAC^® are no longer optional, they're a strategic upgrade. If you’re seeking to lower fuel consumption, reduce maintenance costs, and comply with IMO regulations, upgrading your marine piston ring coatings is one of the most effective places to start.

Want to unlock fuel efficiency through smarter surface engineering?
Contact NTI Nanofilm to learn how our advanced piston ring coatings can enhance your marine engine’s performance.