Sulzer RTA60C: Big Power For Fast-Type Ships

Wärtsilä NSD used the recent NorShipping exhibition in Oslo as a launching pad for its latest offering to the marine world, the Sulzer RTA60C, an engine designed for faster type ship requiring power outputs up to 18,880 kW (25,680 bhp). The RTA60C furthers the mandate to offer cleaner, more efficient power packages in a smaller space and less weight consuming manner. One indication of its compact dimensions is the fact that the six-cylinder version is just 7,620 mm long. Length has been minimized in similar ways to those that have been proven a success in the RTA48T and RTA58T engines. The fact that the cylinder covers each have just four holding-down studs further accounts for the compact arrangements, while simplifying manufacture. The RTA60C has a 600-mm bore and 2,250 mm stroke, and boasts a mcr of 2,360 kW/cylinder (3,210 bhp/cylinder) at 114 rpm. It is available with five to eight cylinders, covering the power range from 8,250 to 18,880 kW (11,200 to 25,680 bhp) at 91 to 114 rpm. This power and speed was designed for a wide range of "faster" ship applications, such as medium-sized containerships (abt. 1,200 to 2,700 TEU), car carriers, RoRo vessels, reefers. Aside from its operational attributes, the new engine is an important plank in Wärtsilä NSD's platform in that it was designed with ease and economy of manufacture in mind. This involves an extensive cooperation with major licensees building Sulzer diesel engines and subcontractors as well. The engine maker incorporated many suggestions from shipowners and shipbuilders, with respect to installation and maintenance. The RTA60C incorporates the latest advances designed to enhance engine performance and longevity, including low piston crown temperatures given by well-adapted jet-shaker cooling; cylinder liners with sufficient hard phase; and fully honed running surface. Piston ring performance is enhanced with the use of anti-polishing rings at the top of the cylinder lines, a concept tested on existing RTA engines with reported good results. The anti-polishing ring has a slightly smaller bore than the cylinder liner so that it helps keep the top land of the piston clean. This stops deposits on the top land from dowing any damage to the liner running surface and its lubrication film. The RTA60C takes advantage of the latest technologies in the Sulzer pipeline, specifically the RT-flex system that uses the Sulzer Common Rail system to give a fully electronically controlled engine that has no need of the camshaft and its individual fuel pumps. The new engine is designed so that it can be efficiently modified to incorporate the RT-flex concept.