近些年,中国国内汽车生产量和消费量不断攀升,引起世界的关注,并使汽车产业成为中国经济发展的主导产业。下面是小编带来的，欢迎阅读!
1
The diameter of the cylinder is called the engine bore.Displacement and compression ratio are two frequently used engine specification.Displacement indicates engine size.and compression ratiocompares the total cylinder volume to compression chamber volume
The term"stoke"is used to describe the movement of the piston within the cylinder.The operating cycle may require either two or four stroke to complete. Most automobile engines operate on thefour stroke cycle
This type of engine is also know as Otto cycle,after the name of its inventor, Nikolaus Otto,who first applied the principle in 1876.In the 4-stroke engine, four strokes of the piston in thecylinder are required to complete one full operating cycle. Each stroke is named after the action.It performs intake, compression,power, and exhaust in that order, shown in Fig.1-2
1.Intake stroke
The piston moves downward to the bottom dead center,a vacuum is created in the cylinder.The intake valve opens and air-fuel mixture comes into cylinder .To obtain the maximum filling of thecylinder the intake valve opens about 10' before t.d.c.giving 20'overlap. The inlet valve remains open until some 50'after b.d.c.to take advantage of mixture.
2.Compression stroke
The air-fuel mixture is compressed within the combustion chamber.While the pressure rise to about 1MP, depending on various factors including the compression ratio, throttle opening andengine speed.The spark plug is fired ignite the air-fule mixture prior to the piston being at the t.d.c..Note that both valves are closed.
3.Power stroke
The air-fuel mixture expands, which creates the power to force the piston downward.The exhaust valve opens near the bottom of the stroke.
4.Exhaust stroke
As the piston starts to move upward, the exhaust valve is opened.The piston moving up force the exhaust gases out of the cylinder.The intake valve usually opens just before the exhauststroke.
This 4-stroke cycle is continuously repeated in every as long as the engine remains running.
汽缸体的直径成为缸径。排量和压缩比经常用来反应发动机的效率。排量由发动机的尺寸决定，汽缸体的总体积除以压缩室的体积成为压缩比。
“冲程”这一个术语是用来描述活塞在汽缸体中的运动的。一个工作循环可以通过两个或者四个冲程来完成大多数的汽车发动机都是四冲程发动机。
这种类型的发动机因为这种四冲程循环而出名，然后是以发明者发明者的名字而命名，尼古拉斯·奥托在1876年第一次运用这种原理。在四冲程发动机中，活塞的四个冲程在气缸中运动来实现完美的运动循环。每一个冲程都是以他们的作用而命名。他们分别按顺序扮演进气、压缩空气、做功和排气。
1.进气冲程
当活塞向下往下止点运动的时候，气缸中就行成了一个真空。这时候进气门打开，空燃混合物进入气缸。为了保证有更多的混合气进入气缸中，进气门在活塞到达上止点之前10’打开。所以就有了一个20’的气门重叠角。为了保证能有更多的混合气进入汽缸，当活塞经过下止点50’之前都是一直保持打开的。
2.压缩冲程
空燃混合物是在燃烧室内被压缩的，而里面的压缩压力上升到大概1MP，要取决于很多因素，其中包括压缩比、节气门开度和发动机的转速。当活塞到达上止点的时候火花塞就点燃里面的空燃混合气，在这整个过程中所有的气门都是关闭着的。
3做功冲程
空燃混合气膨胀产生的力量推动着活塞向下运动，当达到下止点附近的时候排气门打开。
4.排气冲程
当活塞开始往上运动的时候，排气门打开，活塞往上运动迫使废弃排除汽缸体，进气门通常是在排气冲程结束之前打开。
以上这四个冲程就这样连续反复的不断重复，从而使发动机保持运转。
2
About car engine
Of all automobile components,an automobile engie is the most complicated assembly with dominant effects on the function of an autombile.So, the engine is generally called the"heat"of anautomobile.
在汽车的所有部件中，汽车发动机是最复杂的组件，其对整车性能有着决定性的作用。因而发动机往往被称作发动机的“心脏”。
There are actually various types of engines such as electric motors,stream engines,andinternal combustion engines.The internal combustion engines seem to have almost complete dominance of theautomotive field.The internal combustion engine,as its name indicates,burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel thevehicle.
事实上，按动力来源分发动机有很多种，如电动机、蒸汽机、外燃机等。然而内燃机似乎在发动机领域有着绝对的统治地位。就像其字面意思一样，内燃机的染料在气缸内燃烧，通过将燃烧产生气体的膨胀力转换成转动力来驱动发动机前进。
Engine is the power source of the automobile.Power is produced by the linear motion of a piston in a cylinder.However,this linear motion must be changed into rotary motion to turn the wheelsof cars or trucks.The puston 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 rodtransmits the up-and-down motion of the piston to the crankshaft,which changes it into rotary motion.The connecting rod is mounted on the crankshaft with large bearings called rodbearing.Similar bearings, called main bearings,are used to mount the crankshaft in the block.
发动机是整部车的动力来源。能量来自于活塞在气缸内的往复直线运动。然而这种往复直线运动必须要转换成旋转运动才能驱动车轮。活塞与连杆通过一个销来连接，这个销称为活塞销。连杆的下部连接于曲拐。连杆把活塞的上下往复运动传递给曲拐，从而将往复直线运动转变成旋转运动。连杆和曲拐的连接使用大的轴承，称之为连杆轴承，类似的轴承也用于将曲轴连接到机体，称之为主轴承。
They are generally two different types of coolingsystem and air-cooling system.Water-cooling system is more common.The cooling medium, or coolant, in them is eitherwater or some low-freezing liquid, called antifreeze.A water-cooling system consists of the engine water jacket, thermostat, water pump, radiator, radiator cap, fan, fan drive belt andneccessary hoses.
主要有两种类型的冷却系统：水冷和风冷。水冷系统更为普遍。系统所用冷却介质或是冷却液水或其他低凝固点液体，称为抗凝剂。一个完整的水冷系统包括机体水套，节温器，水泵，散热器，散热器罩，风扇，风扇驱动皮带和必需的水管。
A water-cooling system means that water is used as a cooling agent to circulate through the engine to absorb the heat and carry it to the radiator for disposal.The ebgine is cooled mainlythrough heat transfer and heat dissipation.The heat generated by the mixture burned in the engine must be transferred from the iron or aluminum cylinder to the waterin the water jacket.Theoutside of the water jacket dissipates some of the heat to the air surrounding it, but most of the heat is carried by the cooling water to the radiator for dissipation.When the coolanttemperature in the system reaches 90°,the termostat valve open fully, its slanted edge shutting off the sforter circuit so that coolant circulates through the longer one: water-pump-coolingjacket-thermostat-radiator top-tank-radiator core-bottom tank-pump.
水冷系统意味着水将用作冷却介质，用于在发动机中循环吸收热并将之带到散热器中散出。发动机主要是通过热传导和热辐射来散热。由混合气燃烧产生的热通过铁质或铝制气缸传至水套中的冷却水中。水套外部通过向空气散热辐射部分热能，然而主要部分由冷却水带至散热器耗散掉。当冷却液温度达到90度时，节温器阀全部打开，关闭小循环从而使冷却液在大循环中流动：水泵-冷却水套-节温器-进水室-散热器芯-出水室-水泵。
Water pumps have many designs, but most are the centrifugal type.They consist of a rotating fan,or impeller,and seldom are of the positive displacement type that uses gears or plungers.Manywater pumps have a spring-loaded seal to avoid leakage of water around the pump shaft.Some V-type engines have a pump on each cylinder biock.
水泵也有不同的设计，多数使用离心式，这种水泵包括一个螺旋风扇或是叶轮。少数水泵使用齿轮或是柱塞。许多水泵有一个弹簧密封,避免泄漏泵轴周围的水分。一些v型发动机的两个气缸体组各有一个水泵。
The radiator is a device designed to dissipate the heat which the coolant has absorbed from the engine;it is constructed to hold a large amount of water in tubes or other passages whichprovide a large area in contact with the atmosphere.
散热器是用来向外散发冷却液从发动机吸收来废热的装置;其结构中包括可以容纳大量冷却液的管道或其他通道，用来增大与空气的接触面积。
The radiator usually mainly consists of the radiator core, radiator bottom tank,and radiator top tank.Radiator cores are of two basic types,the fin and tubefins are placed around the tubesto increase the area for radiating the heatand of the ribbon cellular or honey comb tybe.The popular fin and tube type of radiator core has the advantage of fewer soldered joints and is therea stronger construction.It consists of a series of pareller tubes extending from the upper to the lower tank.The honeycomb type core consists of a large number of narrow water passage made bysoldering pairs of thin metal ribbons together their edges.These tubes are separated by fins of metal ribbon which help dissipate the heat.
散热器主要包括散热器核心，散热器底部水箱可译为出水室和散热器顶部水箱可译为进水室。散热器核心主要包括两种基本形式，鳍管型鳍片安放在管道旁以增大散热面积和蜂窝型。流行的鳍管型优点在于较少的焊点和由此而来的较高结构强度。其包含很多从进水室向出水室延伸的平行管道.蜂窝型则包含大量由焊接在边缘的成对金属片形成的窄水道，这些水道被鳍片隔开以利于散热。
The radiator cap serves not only to prevent the coolant from splashing out the filler opening,but also to prevevt evaporation of the coolant.
散热器罩不仅用于防止冷却液溅出而且用于防止冷却液的挥发。
The fan designed to draw cooling air through the radiator core. The fan is usually mounted on an extension of the water pump shaft and is driven by V-belt from a pulley mounted on the frontend of the cramshaft.Usually the same belt drives the alternator, and belt tension is adjusted by swinging the alternator on its mounting.
风扇设计来驱使制冷空气通过散热器芯。风扇常常装在水泵轴的伸出物上，由安装在曲轴前段的滑轮上的v带驱动。通常将一台机器的皮带换到另一台机器的时后，带的张紧力需要通过调节安装来调节。
汽车发动机简介
在汽车的所有部件中，汽车发动机是最复杂的组件，其对整车性能有着决定性的作用。因而发动机往往被称作发动机的“心脏”。
事实上，按动力来源分发动机有很多种，如电动机、蒸汽机、外燃机等。然而内燃机似乎在发动机领域有着绝对的统治地位。就像其字面意思一样，内燃机的染料在气缸内燃烧，通过将燃烧产生气体的膨胀力转换成转动力来驱动发动机前进。
发动机是整部车的动力来源。能量来自于活塞在气缸内的往复直线运动。然而这种往复直线运动必须要转换成旋转运动才能驱动车轮。活塞与连杆通过一个销来连接，这个销称为活塞销。连杆的下部连接于曲拐。连杆把活塞的上下往复运动传递给曲拐，从而将往复直线运动转变成旋转运动。连杆和曲拐的连接使用大的轴承，称之为连杆轴承，类似的轴承也用于将曲轴连接到机体，称之为主轴承。
主要有两种类型的冷却系统：水冷和风冷。水冷系统更为普遍。系统所用冷却介质或是冷却液水或其他低凝固点液体，称为抗凝剂。一个完整的水冷系统包括机体水套，节温器，水泵，散热器，散热器罩，风扇，风扇驱动皮带和必需的水管。
水冷系统意味着水将用作冷却介质，用于在发动机中循环吸收热并将之带到散热器中散出。发动机主要是通过热传导和热辐射来散热。由混合气燃烧产生的热通过铁质或铝制气缸传至水套中的冷却水中。水套外部通过向空气散热辐射部分热能，然而主要部分由冷却水带至散热器耗散掉。当冷却液温度达到90度时，节温器阀全部打开，关闭小循环从而使冷却液在大循环中流动：水泵-冷却水套-节温器-进水室-散热器芯-出水室-水泵。
水泵也有不同的设计，多数使用离心式，这种水泵包括一个螺旋风扇或是叶轮。少数水泵使用齿轮或是柱塞。许多水泵有一个弹簧密封,避免泄漏泵轴周围的水分。一些v型发动机的两个气缸体组各有一个水泵。
散热器是用来向外散发冷却液从发动机吸收来废热的装置;其结构中包括可以容纳大量冷却液的管道或其他通道，用来增大与空气的接触面积。
散热器主要包括散热器核心，散热器底部水箱可译为出水室和散热器顶部水箱可译为进水室。散热器核心主要包括两种基本形式，鳍管型鳍片安放在管道旁以增大散热面积和蜂窝型。流行的鳍管型优点在于较少的焊点和由此而来的较高结构强度。其包含很多从进水室向出水室延伸的平行管道.蜂窝型则包含大量由焊接在边缘的成对金属片形成的窄水道，这些水道被鳍片隔开以利于散热。
散热器罩不仅用于防止冷却液溅出而且用于防止冷却液的挥发。
风扇设计来驱使制冷空气通过散热器芯。风扇常常装在水泵轴的伸出物上，由安装在曲轴前段的滑轮上的v带驱动。通常将一台机器的皮带换到另一台机器的时后，带的张紧力需要通过调节安装来调节。
