Lesson-3-Diesel-Engine-Construction(一).docx

精品文档Lesson 3 Diesel Engine Construction (1) 第 3 课 柴油机结构 (1)Bedplate and Frame 机座和机架The bedplate, which in most cases is of the welded design, is bolted to the seating which forms a part of the double bottom of the ship. 在大多数情况下机座是焊接结构，用螺栓固定在构成船舶双层底的底座上It is secured in the transverse direction by means of bolts known as side-chock bolts and in longitudinal direction by means of end-chock bolts.它在横向借助于侧楔垫螺栓，在纵向借助于端楔垫螺栓固定The crankshaft rests in bearings built into cross girders of the bedplate. These bearings, known as main bearings 曲轴安放在机座横梁的轴承上，这些轴承称作主轴承。

each consists of two shells which are supported in housings machined in the bedplate and secured by means of studs and bearing caps 每个轴承由两块轴瓦组成， 两块轴瓦由在机座上加工出的瓦座支撑， 用双头螺栓和轴承盖固土定The thrust block or thrust bearing, located at the aft end of the engine, may be integral with, or separate from the bedplate.即推力轴承位于发动机的尾部，可同机座制成一体，也可同机座分开Onthe flat upper surface of the bedplate are arranged a number of A-shaped frames or entablatures which may be manufactured of cast iron orfabricated steel. The frames are mounted on and bolted to the bedplate cross girders.在机座上平面装有若干铸铁或锻钢制成的 A 形机架， 机架安装在机座的横梁上， 并用螺栓固 定。

At the top of the A-frames there is a strong cast iron frame called the scavenging air boxA 形机架顶部有一个结实的框架结构叫扫气箱which is built of a number sections provided with vertical flanges enabling them to be bolted together to form a block for 1-3 cylinders in front of the chain transmission, and a block with 4-6 cylinders aft of the chain transmission.该扫气箱分若干段，每段均带有垂直法兰，通过螺栓可将它们在链传动装置前 1~3 缸的部分连成一体，链传动装置后 4 缸 ~6 缸的部分连成一体The chain transmission, forming the connection between the crankshaft and the camshaft, is enclosed in a cast iron casing known as the chain drive casing.链传动装置将曲轴和凸轮轴连在一起，封闭在链传动箱的壳体内。

Cylinders and covers 气缸和气缸盖On top of scavenging air box is mounted strong cast iron frame for each cylinder.在扫气箱上部，每个气缸装有一个坚固的铸铁框架These frames are known as cylinder blocks or cooling jackets, which are provided with vertical flanges enabling them to be bolted together in the foremost and aftmost groups in the same way as the scavenging air boxes. 这些框架称作气缸体或冷却水套， 并带有垂直法兰， 与扫气箱一样， 可用螺栓将各框架连成 首尾一组The bedplate, frames and cylinder blocks are secured together by long tie-rods to achieve a greater rigid construction with less deformation in service and lower vibration.机座、 机架和气缸体用长贯穿螺栓连到一起， 形成一个较大的坚实结构， 减少了使用时产生 的变形及振动。

The cylinder liners are madeof alloyed cast iron and the cylinder surfaces are sometimes chromium-plated.气缸套由铸铁制造，缸套表面有时镀铬The cylinder liners are extend somewhat down in the scavenging air box 气缸套有些向下延伸到扫气箱and sealing between the liner and the top of the scavenging air box is achieved by the rubber rings fitted into the slots machine-turned in the liners.缸套与扫气箱顶部的密封由橡胶圈实现，橡胶圈安装在缸套上切削的环槽内In the part of the cylinder liner inside the scavenging air box there is a series of openings known as scavenging air ports.在气缸套伸入扫气箱内的部位有一列开口就是所谓的扫气口。

These ports are located at such a height that they are just exposed bythe upper edge of the piston when the piston is in the bottom dead-centre position.气口的高度是这样布置的，当活塞位于下止点时，活塞上缘刚好打开气口The ports are drilled in the liners at an angle of approx. 20, the result being that the scavenging air is given a rotary movement.气口在缸套上以大约 200 的倾角钻成，其结果是使扫气旋转Each cylinder is closed at the top by a cylinder cover, madeof a special heat-resistant steel, the cover is mounted against a flat surface at the top of the cylinder liner and located on the liner by means of a machine-turned guide edge.缸盖装在缸套顶部的平面上， 并由机械加工的凸肩定位。

密封圈嵌入在缸盖锥形部分车削的 环槽中A sealing ring is inserted in a groove turned in the conical part of the cover. The fitting of the sealing ring in the conical surface must be carried out with great care. The cylinder covers and the liners are bolted together by means of studs screwed onto the cylinder frames.将密封圈嵌入锥形面时必须十分小心气缸盖和气缸套用旋入缸体中的双头螺栓固定The cylinder liner has drillings for cylinder lubrication, and, in later types, has drillings for cooling water at the uppermost part of it. 缸套上有钻孔，用于润滑，新型的缸套在其最上部钻孔用于冷却。

In each cylinder cover is a large central opening for mounting the exhaust valve, and two or three holes for the fuel valves.每个缸盖上有一个大型的中心孔，用于安装排气阀，还有两到三个用于装喷油器The cylinder cover is also provided with holes for: the starting valve; the safety valve; the indicator cock; the cooling water inlet and the cooling water outlet to the exhaust valve cooling chamber. 还有些孔用来安装起动阀、安全阀、示功阀，以及排气阀冷却水腔的进出口2欢迎下载 精品文档ExhaustmanifoldPistun rodAir inlet portsExhaust portCruishcaLlConnecting rodBottom end hearingA-liiimcCrankshaft【决dpi ateI urboblowerPistonFiR. 3T A 2-stroke ditstd tngintB. Multiple Choice 选择题Questions 1 —5 are based on paragraphs 1 —3.根据课文第1-3段回答问题，1-51. How is the bedplate secured in the longitudinal direction?机座在纵向上是如何固定的 ？答素.AA. By means of end-chock bolts.借助于端楔垫螺栓B. By means of tie bol。