TAILIEUCHUNG - Lesson 12-Marine Diesel Engines (3)
Tham khảo tài liệu 'lesson 12-marine diesel engines (3)', ngoại ngữ, anh văn thương mại phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Lesson 12-Marine Diesel Engines 3 Indeed a diesel engine is really a very complex and complicated combination of thousands and thousands of elements. Apart from its various parts there are also a few auxiliary systems in a diesel engine. They are as follows 1. The Fuel Injection System The fuel injection system in delivering the liquid fuel to the combustion chamber must fulfill the following assignments A To measure the correct quantity of the fuel to be injected. B To time the fuel injection. C To control the rate of fuel injection. D To atomize or break up fuel into fine particles. E To distribute fuel properly in the combustion chamber. 2. The Combustion System There are three basic models of combustion chambers namely direct injection or open chamber swirl chamber and pre-combustion chamber. Whether the engine is a four-stroke one or a two-stroke one is not of radical significance but there is in fact less freedom of choice with two-stroke engines because with the two-stroke cycle it is necessary to maintain a pattern of scavenge flow as well as a pattern of combustion air movement in the meanwhile. The trouble is that combustion chambers that produce a very vigorous air movement may disrupt the scavenge pattern and so a relatively quiescent chamber is to be preferred for two-stroke engines. nozzle _ __ pressure oil pipe release coct release cock Main hnghie pump speed governor fuel oil System ÇOUpÜTl purified fuel oil overflow nr j fled fuel oil tank Fig. 3. The Lubrication System A lubricant often has to perform many duties in any one situation in addition to its fundamental job of reducing friction and wear. These duties may include acting as a rust preventative a coolant a sealing agent a hydraulic fluid and a flushing agent to remove dust and metallic particles. 4. The Cooling System The purpose of the cooling system is to keep an engine at its most efficient operating temperature at all speeds and under all driving .
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