tailieunhanh - Lesson 10-Marine Diesel Engines (1)

Tham khảo tài liệu 'lesson 10-marine diesel engines (1)', ngoại ngữ, anh văn thương mại phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Lesson 10-Marine Diesel Engines 1 The technical term outfitting is relevant to a wide range of knowledge in the light of the latest classification in the shipbuilding circle in Japan. In addition to ship outfitting which is dealt with in Ship Equipment outfitting also concerns engine outfitting electricity outfitting and painting. From this lesson on we shall come to learn the engine outfitting. It is known to all that the propulsion plant of a ship is often compared to one s heart and the hull to one s body. In general a propulsion plant will appear in four basic types namely marine diesel engine gas turbine engine steam engine and atomic power with marine diesel engines most widely employed on board the ship. Therefore emphasis is to be put upon marine diesel engines. Before we set to work on the detailed construction of diesel engine parts we should first know something about the several classes into which diesel engines may be divided. It s quite O. K. for us to classify diesel engines in several ways. For example according to operating cycle engines can be divided into two groups based on the number of piston strokes per cycle either four strokes or two strokes. Accordingly there are respectively a four-stroke cycle engine and a two-stroke cycle engine. The difference between them is that a two-stroke engine ignites twice as often as a four-stroke engine. Then two-stroke engines may be further classified by the methods used to supply an engine with fresh air i. e. crankcase scavenging or blower scavenging pump scavenging In consideration of scavenging ways we must not neglect another two essential concepts longitudinal uniflow scavenge and transversal scavenge. Fig. Moreover by piston action diesel engines may be classified as single-action or double-action. Secondly the piston may be connected to the upper end of a connecting rod either directly or indirectly and according to piston connection there will be trunkpiston engines and crosshead engines .