Lesson7OperationandMaintenanceofMainEngine第7课主机的操作和维护保养PPT课件

1、Lesson 7 Operation and Maintenance of Main Engine第7课 主机的操作和维护保养Medium- and slow-speed diesel engines will follow a fairly similar procedure for starting and manoeuvring. Operating Procedures Where reversing(换向换向) gearboxes or controllable-pitch propellers (调距桨调距桨) are used then engine reversing is n

2、ot necessary. A general procedure is now given for engine operation which details the main points in their correct sequence. Where a manufacturers instruction book is available this should be consulted(参考参考,商量商量) and used.1. Before a large diesel is started it must be warmed through by circulating h

3、ot water through the jackets, etc. This will enable the various engine parts to expand in relation to one another.Preparations for standby2. The various supply tanks(补补给柜给柜), filters, valves and drains (放残装置放残装置) are all to be checked.3. The lubricating oil pumps and circulating water pumps are star

4、ted and all the visible returns should be observed. 4. All control equipment and alarms should be examined for correct operation.5. The indicator cocks(示功考示功考克克) are opened, the turning gear(盘车机盘车机) engaged and the engine turned through several complete revolutions. In this way any water which may h

5、ave collected in the cylinders will be forced out(排出排出).6. The fuel oil system is checked and circulated with hot oil.7. Auxiliary scavenge blowers(辅辅助 扫 气 泵助 扫 气 泵 , 辅 助 鼓 风 机辅 助 鼓 风 机 ) , i f manually operated, should be started.8. The turning gear is removed and if possible the engine should be t

6、urned over on air before closing the indicator cocks.9. The engine is now available for standby. The length of time involved in these preparations will depend upon the size of the engine.1. The direction handle is positioned ahead(正车正车) or astern(倒车倒车). This handle may be built into the telegraph re

7、ply lever(车钟应答手柄车钟应答手柄).Engine startingThe camshaft is thus positioned relative to the crankshaft to operate the various cams for fuel injection, valve operation, etc.2. The manoeuvring handle is moved to “start”. This will admit compressed air into the cylinders in the correct sequence to turn the

8、engine in the desired direction. A separate air start button may be used.3. When the engine reaches its firing speed the manoeuvring handle is moved to the running position. Fuel is admitted and the combustion process will accelerate the engine and starting air admission will cease.When running at m

9、anoeuvring speeds:1. Where manually operated auxiliary blowers are fitted they should be started.Engine reversing2. The fuel supply is shut off and the engine will quickly slow down.3. The direction handle is positioned astern.4. Compressed air is admitted to the engine to turn it in the astern dire

10、ction.5. When turning astern under the action of compressed air, fuel w i l l b e a d m i t t e d . T h e combustion process will take over and air admission cease.When running at full speed:1. The auxiliary blowers, where manually operated, should be started.2. Fuel is shut off from the engine.3. T

11、he direction handle is positioned astern. 4. Blasts of compressed air may be used to slow the engine down.5. When the engine is stopped, compressed air is admitted to turn the engine astern and fuel is admitted to accelerate the engine. The compressed air supply will then cease. Engine builders supp

12、ly detailed instructions on the operation and maintenance of their machinery so that regular maintenance work can be carried out and breakdowns(故故障障) can be kept to a minimum. Maintenance维护保养维护保养These instruction manuals(说说明书明书,操作手册操作手册) are usually kept by the chief engineer, but they are made avai

13、lable to all members of the engine-room staff. The intervals at which an engine and its parts must be inspected will vary from make to make and will depend on the use the engine has been put to, and therefore the brief outline(摘要摘要) which follows is meant only as a general guide(普遍指导普遍指导). At freque

14、nt intervals, fuel pumps should be examined and adjusted if necessary. When the engine is running, this will be shown by comparing engine indicator cards and by exhaust temperatures. Pistons should also be examined frequently for cracks. At intervals of six weeks, the fuel valves should be taken out

15、 and carefully inspected. Atomizers(喷嘴喷嘴) and filters can b e w a s h e d w i t h c l e a n paraffin(煤油煤油) and then dried in warm place. Cleaning rags(破布破布) mustnt be used because they leave behind small pieces of fluff(绒毛绒毛), which may block up holes. Valve seats should also be tested and if they a

16、re pitted(麻点麻点) or scratched(划划痕痕), the surface should be reground(重新研磨重新研磨). At intervals of one month, the upper piston rings should be examined, if possible, for the firstsix months service. After that inspection periods can be extended so long as their condition continues to be satisfactory. At

17、intervals of six months, the upper pistons, if cooled, must be inspected for deposits of carbon in cooling spaces and cooling pipes. When new piston rings are fitted, care must be taken to ensure there is sufficient clearance to allow for the expansion of the rings.Exhaust belts and manifold must be

18、 examined and excessive carbon deposits removed. All carbon deposits should also be removed from cylinder ports. Cylinder liners must be examined externally for deposits of scale.If these deposits cant be removed by flushing with water, then the liner must be removed for cleaning. The liner should a

19、lso be measured for wear and renewed, if the limit for wear has been reached.The clearance of connecting rod top and bottom ends should also be examined every six months and adjusted if necessary. In addition, lubricating oil sumps and tanks should be cleaned of sediment. At intervals of one year the manoeuvring gear(操纵机构操纵机构) must be examined for