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Intro to Marine Engineering 2 2011 Part 3

Tham khảo tài liệu 'intro to marine engineering 2 2011 part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 50 Diesel engines Exhaust gas from the engine is passed into a constant-pressure receiver and then into the turbochargers. Scavenging is uniflow and electrically driven auxiliary blowers are automatically started during low-load operation. Lubricating oil is supplied to the various bearings and also to the pistons for cooling. Cylinder oil is supplied via lubricators from a high-level service tank. A separate lubrication system is provided for the camshaft bearings to prevent contamination of the main lubricating oil system. Fresh water cooling is provided for the cylinder jackets cylinder covers and exhaust valves. The engine is designed to run on diesel oil or heavy fuel oil. An electronic governor is provided as standard. Pielstick The Pielstick PC series engines are single-acting medium-speed four-stroke reversible types. Both in-line and V-configurations are available. The running gear being a trunk-type engine is made up of the piston and the connecting rod which joins the single-throw crankshaft. The arrangement of a PC4 engine is shown in Figure 2.30. The crankcase and frame are constructed from heavy plate and steel castings to produce a low-weight rigid structure. The crankshaft is underslung and this arrangement confines all stresses to the frame structure. The crankshaft is a one-piece forging and the connecting rods are H-section steel stampings. The one-piece cylinder head contains two exhaust and two inlet valves together with a starting air valve a relief valve indicator cock and a centrally positioned fuel injector. Exhaust-gas-driven turbo-chargers operating on the pulse system supply pressurised air to the engine cylinders. Bearing lubrication and piston cooling are supplied from a common system. The engine has a dry sump with oil suction being taken from a separate tank. The cylinder jackets are water-cooled together with the cylinder heads and the exhaust valve cages. The charge air cooler may be fresh-water or sea-water cooled as required. .