New Ring Pack for Heavy Duty Diesel Engines 2007-01-2846
Stricter emission regulations on Heavy-Duty Diesel (HDD) engines have brought more demanding conditions to the engine piston ring pack. This work shows and discusses some of the new features of modern HDD ring packs. The presented ring pack comprises a fully nitrided, PVD (Physical Vapor Deposition) coated, top ring. The second ring can still be a cast iron, Chromed Plated but there are also nitrided steel projects for higher durability and robustness. The oil control ring is a narrow, for better conformability, I-Shaped nitrided.
Some of the ring characteristics are discussed in the paper: the PVD coating showed excellent compatibility with the smoother cylinder finishes that are being used to reduce Lube Oil Consumption. PVD coated top rings also presented lower radial wear when compared with the traditional Ceramic-Chromium coating.
For the Oil ring, the presented narrow 3.0 mm width Oil ring presents more than the double of the conformability of usual HDD oil rings, especially important for good performance in deformed cylinder bores. Conical face profile can be used for better oil control during break-in. If necessary, PVD can be also applied in the oil ring running face for additional longer durability.
Similar ring packs are being homologated in different HDD engines.