Liquid nitriding is a subcritical surface enhancement process with one of the longest track records of success of any case hardening technology.
PVD coatings involve the deposition of thin (2-10 microns; 0.0001" – 0.0004") films on the surface of tools and components.
The LT4 uses the stout LT1 architecture and enhances it with a stronger crank and (steel) rods, coated and forged pistons, DLC coated wrist pins, titanium intake valves (needed for higher RPM), stronger rotocast 356 alloy cylinder heads, larger oil cooler, bigger fuel pump, and an optimized camshaft.
“Thanks to diamond-like carbon coating, we can use lower tension on the Ecotec’s piston rings to reduce friction, which improves fuel economy.”
“With its new 1.8 liter engine and next-generation XTRONIC CVT (Continuously Variable Transmission), the all-new world sedan delivers spectacular fuel potency, an extended piston stroke and Twin Continuously variable valve timing management (C-VTC) optimize combustion, whereas hydrogen-free Diamond Like Carbon (DLC) coating on valve lifters halves friction of previous coatings and beehive valve springs scale back friction and inertial loss.”
“Innovative anti-friction coatings like CrN Physical Vapor Deposition (PVD) coating and Diamond Like Carbon (DLC) coating.”
“The B6304T T6 benefits from improved valve tappets, which feature Diamond like Carbon (DLC) coating. The carbon structure is extremely hard and has self-lubricating properties. The DLC surface reduces camshaft friction, enabling lower fuel consumption and extending service life.”
Automotive Engineering International, Feb. 7, 2012
“Friction Reduction was a priority and includes a new coating applied to the piston pins”
“Engine friction is reduced by specially coated pistons, low tension piston rings, low friction crank seals and a cambelt-in-oil design, which also improves refinement”
“Low-friction coatings on the piston rings and highly polished surfaces on the tappet”
“Graphite-coated piston skirts DLC (Diamond Like Carbon) coated cam followers, a technique that has been employed in F1 for some years. Benefits are significantly reduced friction and enhanced energy efficiency for uprated performance and improved fuel consumption.”
“Energy dCi 90 and 75 are packed with advanced technology, including features that stem from Renault’s presence in Formula 1. For example, the DLC-coated cam followers use a technique (Diamond Like Carbon) that has been employed in motor racing for some years. The mechanical properties of DLC significantly reduce friction and improve energy efficiency to deliver enhanced performance and contained fuel consumption.”
“CarboGlide® coating delivers a direct improvement in fuel economy and CO2 emissions by reducing ring friction by up to 20 percent as compared to nitride or other commonly used coatings… CarboGlide’s superior coating properties are achieved due to a multi-layer microstructure and a special coating composition that contains carbon, deposited in diamond-like form, as well as hydrogen and tungsten.”