外文翻译--发动机工作原理

附录 1 Engine Operating Principles Most automobile engines are internal combustion,reciprocating 4-stroke gasoline engines,but other types have been used,including the diesel,the rotary(wankel),the 2-srtoke,and stratified charge.Reciprocating means up and dowm or banck and forth ,It is the up and down action of a piston in the cylinder blick,or engine block.The bilck is an iron or aluminum casting that contains engine cylinders and passges called water jackets for coolant circulation.The top of the block is convered with the cylinder head.Which forms the combustion chanber.The bottom of the block is covered with an oil pan or oil sump. Power ia produced by the linear motion of a piston in a cylinder.However,this linear motion must be changed into rotary motion to turn the wheels of cars of trucks.The piston is attached to the top of a connecting rod by a pin ,called a piston pin or wrist pin.The bottom of the connecting rod is attached to the crankshaft.The connecting rod transmits the up-and-down motion of the piston to the crankshaft,which changes it into rotary motion. Term: stroke is used to indicate the movement within the cylinder piston, piston stroke is the distance from the engine type according to need two-stroke or four-stroke cycle to finish a job and four stroke engines are also called otto engine, in order to commemorate German engineers otto, he is the first application in 1876, the principle of in four stroke engines, cylinder piston required to complete a four-stroke cycle, each stroke work according to their behavior named respectively: intake stroke, compression stroke, function and exhaust stroke. 1. Intake stroke When the piston moves down, spray the mixture through open after entering the inlet valve, in order to achieve maximum cylinder amount of inlet in Detroit, arrive before BDC 10 , open and exhaust has 20 to open the inlet valve overlap, has been opened to the pistons to come fully into the mixture after about 50 . 2. Compression stroke The piston start moving up huge inlet valve closed, and the mixture in the combustion chamber, according to the different factors including compression compression ratio, the throttle valve, pressure revs up to about 1 mpa, close to the top, the spark plug stroke produces the spark gap in the breakdown ignition mixture lighting. 3. Doing work Burning gas pressure of inflation rose to 3.5 mpa, promote the piston moves to the cylinder, and exhaust door open. 4 gas stroke With exhaust before more open about 50 , piston, make up in the air pressure drops in exhaust stroke, reduce backpressure, discharge waste piston stroke, for the next intake, normally, inlet in exhaust before opening. Only the engine keep running, each cylinder within four four-stroke cycle continuously.Two stroke engine also through the four-stroke cycle to complete a job but intake stroke, compression stroke for a stroke, do work schedule another stroke, the four-stroke cycle and two terms two travel itinerary is called the term two-cycle but actually not so accurate. However,the intake and the compression actions are combined in one seroke,and the power and exhaust actions are combined in the other stroke.The term 2-stroke cyde or 2-stroke is preferred to the term 2-cyde,which is really not accurate. In automobile engines,all pistons are attached to a single crankshaft.the more cylinders an engine has,the more power strokes produced for cach revolution.This means that an 8-cylinder engine runs more smoothly bacause the power atrokes are closer togther in time and in degrees of engine rotation.The cylinders of multi-cylinder automotive engines arranged in one of three ways. 1.Inline engines use a single block of cylinder.Most 4-cylinder and any 6-cylinder engines are of this design.The cylinders do not have to be vertical.They can be inclined either side. 2.V-type engines use two equal bands of cylinders,usually inclined 60 degrees or 90 degrees from the cach other.Most V-type engines have 6 or 8 cylinders,although v-4 and v-12 engines have been built. 3.Horizontally opposed,or pancake engines have two equal banks of cylinders 180 degrees apart.These space saving engine designs are often air-cooled,and are found in the Chevrolet Carvair,Porsches,Subaus,and Volkswagens.Subaus design is liquid cooled.are often air-cooled,and are found in the Chevrolet Carvair,Porsches,Subaus,and Volkswagens.Subaus design is liquid cooled.Late-model Volkswagen vans use a liquid-cooled version of the air cooled VWhorizontally opposed engine. 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，但是也有使用其它类 型的发动机，包括柴油机，转子发动机，二冲程发动机和分成燃烧发动机。往复的意思就是上下运动或前后运动，在往复发动机中，汽缸中活塞的上下运动产生发动机的动力，这种那个类型几乎所有的发动机都是依赖汽缸体即发动机缸体，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的水套。缸体的顶部是汽缸盖，它组成了燃烧室，缸体地步是油底壳。 气缸内活塞的直线运动产生动力，然而，必须将直线运动转化成旋转运动，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运动，连杆式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。 气缸的直径称为发动机的内径，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，压缩比试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工作循环四冲程发动机也叫做奥托发动机，为了纪念德国工程师奥托，他是在 1876 年第一个应用该原理的，在四冲程发动机中，要求气缸活塞四冲程来完成一个工作 循环，每个冲程根据其行为命名分别为：进气冲程，压缩冲程，作功冲程和排气冲程。 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、排气门有 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 活塞开始向上移动是时，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，发动机转速压力上升到约 1 兆帕，接近冲程顶部时，火花塞产生的电火花在击穿点火间隙点燃可燃混合气。 3.作功 冲程 燃烧膨胀的气体产生的压力上升到 3.5 个兆帕时，推动活塞下移，接近汽缸底时，排气门打开。 4.燃气冲程 随着排气门开启约不止点前 50，活塞回升，使气缸内压力下降在排气冲程，减少对活塞回压，排出废气，为下一个进气冲程作准备，通常情况下，进气门在排气冲程完成前打开。 只有发动机保持运转，每个气缸内四个冲程循环连续不断地重复下去。 两冲程发动机也同样通过四行程来完成，一个工作循环但是进气冲程，压缩冲程合为一个冲程，作功冲程行程另一个冲程，术语两行程循环和两行程就是所谓的术语双循环但实际上并不太准确。 在所用 的汽车发动机中，所有的活塞都是固定在一个曲轴上的，汽缸中发动机越多，每转