中英文文献翻译-发动机工作原理概述

1、 附录 A 外文文献Engine operating principlsMost automobile dngines are internal combustion, reciprocating4-stroke gasolineengines, but other types have been used, including the diesel, the rotary (wankel),the2-stroke ,and stratifild charge.Recipprocating means up and down or banck and forth, it is the up a

2、n down action of apiston in the cylinder blick ,or engine block . the blick is an iron or aluminum casting thatcontains engine cylinders and passage called water jackets for coolant circulation .the top ofthe block is covered with the cylinder head. Which forms the combustion chanber. Thebottom of t

3、he block is covered with an oil pan or oil sump.Power is produced by the linear motion of a piston in a cylinder.however, this linearmotion must be changed into rotary motion to turn the wheels of cars of trucks. The pistionis attached to the top of a connecting rod by a pin, called a pistion pin or

4、 wrist pin thebottom of the connecting rod is attached to the crankshaft . the connecting rod transmits theup-and-down motion of the piston to the crankshaft , which changes it into rotarymotion.The connecting rod is mounted on the crankshaft with large beaings called rod bearings.Similar bearings,

5、called main bearings, are used to mount the crankshaft in the block .shownin fig ,1-1.The diameter of the cylinder is called the engine bore. Displacement and compressionratio are two frequently used engine specifications. Displacement indicates engine size , andcompression ratio compares the total

6、cylinder volume to compression chamber volume.The term stroke is uesd to describe the movement of the iston within the cylinder, aswell as the distance of pistion travel. Depending on the type of engine the operating cyclemay require either two or four strokes to complete. The 4-strokes engine is al

7、so called ottocycle engine ,in honor of the german enginner , Dr. Nikolaus otto , who first applied theprinciple in 1876 . In the 4-stroke engine ,four strokes of the piston in the cylinder arerequired to complete one full operating cycle .Each stroke is named after the action itperformes instake ,

8、compression ,power, and exhaust in that order, shown in Fig1-2.1、Instake strokeAs the piston moves down , the vaporized mixture of fuel and air enters the cylinder through open instake vavle. To obtain the maximum filling of the cylinder the instake valveopens about 10 before t.b.c ,giving 20 overla

9、p. The inlet valve remains open until some50 after b.d.c to take advantage of incoming mixture.2、Compression strokeThe pieton turns up , the instake valve closes, the mixture is compressed within thecombustion chamber, while the pressure rise to ahout 1 Mpa, depending on various factorsinclouding th

10、e compression ratio, throttle opening and engine speed. Near the top of thestroke the mixture is ignited by a spark which bridge the gap of the spark plug.3、Power strokeThe expanding gases of combution produces a rise in pressure of the gas to some3.5Mpa, and the piston is forced down in the cylinde

11、r. The exhaust valve opens near thebottom of the stroke.4、Exhust strokeThe piston moves back up with the exhause valve open some 50beforeb.d.d.,allowing the pressure within the cylinder to fall and to reduce back pressure onthe piston during the exhaust stroke, and the burned gases are pushed out to

12、 prepare for thenext instake stroke. The instake valve usually opens just before the exhaust stroke.This 4-stroke cycle is continuously repared in every as long as the engineremainsrunningA-2-stroke engine also goes through four actions to complete one operating cycle.However , the instake and the c

13、ompression actions are combined in one seroke,and thepower and exhaust actions are combined in the other stroke. The term2-stroke cycle or2-stroke cycle or 2-stroke is preferred to the term 2-cycle, which is really not accurate.In automobile engines, all pistons are attached to a single crankshaft.

14、The morecylinders an engine has ,the more power strokes produced for cach revolusion. This meansthat means that an 8-cylinder engine runs more smoothly because the power atrokes arecloser together in time and in degrees of engine rotation.The cylinder of multi-cyclinder automotive engines arranged i

15、n one of three ways.1、Inline engine use a single block of cylinder. Most 4-cylinder and 6-cylinder engines areof this design. The cylinder do not have to be vertical. They can be inclined either side.2、V-type engine use two equal bands of cylinder , usually inclined 60degrees or 90degreesfrom the ca

16、ch other. Most V-type engines have 6 or 8 cylinders, although V-4 and V-12 engine have been built.3、Horizontally opposed or pancake engine have two equal banks of cylinders 180degreesapart . these space saving engine designs are often air-cooled,and are found in thechevrolet carvair porsches, Subaus

17、,and Volkswagens. Subaus design is liquidcooled.Later model Volkswagen vans use a liquil-cooled VWhorizontally opposedengine. 附录 B 中文翻译发动机工作原理大多数汽车的发动机是内燃机，往复四冲程汽油机，但是也有使用其他类型的发动机，包括柴油机，转子发动机二冲程发动机和分程燃烧发动机。往复的意思就是上下或前后运动，在往复发动机中，气缸中活塞的上下运动产生发动机的动力，这种类型几乎所有的发动机都是依赖气缸体即发动机缸体，缸体是铸铁或铸铝制的，它包括发动机气缸和冷却液循环用

18、的水套，缸体的顶部是气缸盖，它组成了燃烧室，缸体底部是油底壳。气缸内活塞的运动产生动力，然而，必须将直线运动转化为旋转运动，使汽车车轮转动，活塞销将活塞连接在连杆顶部，连杆底部与曲轴连接，使汽车车轮转动，活塞销将活塞连杆顶部、连杆底部与曲轴连接，连杆将活塞的往复运动传递给曲轴，曲轴将其转化为旋转动力，连杆是用连杆曲轴安装在曲轴上的，用类似的轴承即主轴承将曲轴固定在缸体内。气缸的直径成为发动机的内径，排量和压缩比是两个常用的发动机参数，排量是指发动机的大小，压缩比是气缸总容积与燃烧室压缩容积之比。术语：冲程是用来说明活塞在气缸内的运动，也就是活塞行程的距离根据发动机类型的需要二冲程或四冲程来完成一个完整的工作循环，每个在冲程根据其行为命名分别为：进气冲程、压缩冲程、作功行冲程和排气行冲程。1、进气冲程当活塞下移时，雾化后的可燃混合气通过打开的进气门进入气缸，为了达到最大的进气量，进气门在活塞到达上止点前 10打开，使进、排气有20打开重叠角，进气门一直打开到活塞到达下止点充分进入混合气之后 50左右。2、压缩冲程活塞开始向上移动时，进气门关闭，混合气在燃烧室中压缩，根据不同因素包括压缩比，节气门开度，发动