汽車專業(yè)英語(yǔ)

1、It is well-known that the automobile is composed of four sections such as engine, chassis, body and electrical system. 眾所周知，汽車都由發(fā)動(dòng)機(jī)、底盤、車身以及電氣系統(tǒng)四部分組成。 The engine which is called the heart of a vehicle is used to supply power for an automobile. It includes the fuel, lubricating, cooling, ignition and

2、starting systems. Generally, an automobile is operated by internal combustion engine. The internal combustion engine burns fuel within the cylinders and converts the expanding force of the combustion or explosion into rotary force used to propel the vehicle. 發(fā)動(dòng)機(jī)是汽車的心臟，向汽車提供動(dòng)力。它包含有燃料系統(tǒng)、潤(rùn)滑系統(tǒng)、冷卻系統(tǒng)、點(diǎn)火系統(tǒng)

3、和起動(dòng)系統(tǒng)。汽車一般采用內(nèi)燃發(fā)動(dòng)機(jī)。內(nèi)燃發(fā)動(dòng)機(jī)在汽缸里燃燒燃料將內(nèi)燃所產(chǎn)生的膨脹力轉(zhuǎn)變成旋轉(zhuǎn)力，用以推動(dòng)車輛前進(jìn)。 The chassis is a framework used to assemble auto components on it. The chassis itself is divided into four systems like transmission system, suspension system, steering system and brake system. 底盤是一個(gè)用以總裝汽車部件的框架。底盤本身可以分成四個(gè)系統(tǒng)，即傳動(dòng)系統(tǒng)、懸架系統(tǒng)、轉(zhuǎn)向系統(tǒng)和制動(dòng)

4、系統(tǒng)。 The transmission system applies to the components needed to transfer the drive from the engine to the road wheels. The main components are clutch, gearbox, drive shaft, final drive and differential. 傳動(dòng)系統(tǒng)運(yùn)用所需部件將發(fā)動(dòng)機(jī)產(chǎn)生的動(dòng)力傳遞到車輪。它的主要部件有離合器、變速器、傳動(dòng)軸、后橋和差速器。 The primary purpose of the suspension system

5、is to increase strength and durability of components and to meet customers requirements for riding comfort and driving safety. In automobile suspension, the major component is springs. The springs used on todays vehicles are engineered in a wide variety of types, sizes, rates and capacities. Spring

6、types include leaf springs, coil springs and torsion bars. Springs are paired off on vehicles in various combinations, and are attached to vehicle by different mounting techniques. 懸架系統(tǒng)的主要目的是提高零部件的強(qiáng)度和壽命，并滿足顧客對(duì)車輛乘坐舒適性和駕駛安全性的需求。汽車懸架上的主要部件是彈簧。在當(dāng)今車輛上使用的彈簧被設(shè)計(jì)制造成許多不同的型號(hào)、大小、標(biāo)準(zhǔn)及負(fù)載。彈簧類型包括鋼板彈簧、螺旋彈簧和扭力彈簧。彈簧以各種

7、組合形式在車輛上配套使用，并用不同的裝配技術(shù)將彈簧裝在車輛上。 The function of the steering system is to provide the driver with a means for controlling the direction of the vehicle as it moves. The steering system consists of steering wheel, steering shaft, worm, gear sector, pitman arm, drag link, steering knuckle arm, king pin

8、, steering arms, tie rod, front axle and steering knuckle. They enable the car to change the direction by means of turning and moving forth and back. 轉(zhuǎn)向系統(tǒng)的用途是在駕駛員的操縱下控制汽車行駛的方向。轉(zhuǎn)向系統(tǒng)包括轉(zhuǎn)向盤、轉(zhuǎn)向軸、蝸桿、扇形齒輪、轉(zhuǎn)向搖臂、直拉桿、轉(zhuǎn)向節(jié)臂、主銷、轉(zhuǎn)向臂、轉(zhuǎn)向橫拉桿、前軸和轉(zhuǎn)向節(jié)。這些零部件前后移動(dòng)或轉(zhuǎn)動(dòng)，可以使汽車改變運(yùn)動(dòng)方向。 The automobile brake system is a friction

9、device to change power into heat. When the brakes are applied, they convert the power of momentum of the moving vehicle kinetic energy) into heat by means of friction, thus retarding the motion of the vehicle. Structurally, an automotive brake system contains these major parts like brake drum, brake

10、 shoe, brake lining, etc. Functionally, an automotive brake system can be divided into wheel brake mechanism and parking brake mechanism. 汽車制動(dòng)系統(tǒng)是一種將動(dòng)力轉(zhuǎn)變?yōu)闊崃康哪Σ裂b置。當(dāng)使用制動(dòng)器時(shí)，制動(dòng)器通過摩擦將行駛車輛的動(dòng)量力轉(zhuǎn)變成熱量，從而使車輛運(yùn)動(dòng)停滯。從結(jié)構(gòu)上講，汽車制動(dòng)系含有幾個(gè)主要部件，如制動(dòng)鼓、制動(dòng)蹄片、制動(dòng)器摩擦襯片等。從功能上講，汽車制動(dòng)系可分為行車制動(dòng)機(jī)構(gòu)和停車制動(dòng)機(jī)構(gòu)。 The automobile body serves the

11、obvious purpose of providing shelter, comfort and protection for the occupants. The body is generally classified into four sections: the front, the rear, the top and the underbody. These sections can further fall into a lot of assemblies and parts, such as the hood, the fenders, the roof panels, the

12、 door, the instrument panel, the bumpers and the luggage compartment. 車身的基本功能就是向乘員提供保護(hù)，使其乘坐舒適并保證安全。車身一般分為四個(gè)部分:車前部、車后部、車頂部和車下部。這些部分可以進(jìn)一步分為許多的分總成和部件，如發(fā)動(dòng)機(jī)蓋板、擋泥板、車身頂板、車門、儀表板、汽車保險(xiǎn)杠和行李箱。 The electric system supplies lighting and driving power for the automobile. It cranks me engine for starting. It suppli

13、es the high-voltage surges that ignite the compressed air-fuel mixture in the combustion chambers. The electric system includes the battery, generator, starting system, ignition system, lighting system, horn system, radio and other devices. 電氣系統(tǒng)向汽車提供照明與驅(qū)動(dòng)電力。它能起動(dòng)發(fā)動(dòng)機(jī)、提供高壓電脈沖點(diǎn)燃燃燒室中空氣和燃油的高壓混合氣等。電氣系統(tǒng)包括電池

14、、發(fā)電機(jī)、起動(dòng)系統(tǒng)、點(diǎn)火系統(tǒng)、照明系統(tǒng)、喇叭、收音機(jī)以及其他裝置。 The auto description above seems to conclude that though automobiles are quite different in design, they are basically similar in structure. 綜上所述，盡管汽車的設(shè)計(jì)變化很大，然而汽車的構(gòu)造基本上是一樣的。 Text Four-stage-engine Operation There are various types of engines such as electric motors,

15、 steam engines and internal combustion engines. But, the internal combustion engine seems to be the one most commonly used in the automotive field. According to the fuel energy used, internal combustion engines are further divided into gasoline engines, kerosene engines, diesel engines, etc. 四行程發(fā)動(dòng)機(jī)工

16、作過程 發(fā)動(dòng)機(jī)有各種各樣的類型，如電動(dòng)機(jī)、蒸汽機(jī)和內(nèi)燃機(jī)。但是，在汽車領(lǐng)域里內(nèi)燃機(jī)似乎是用得最為普遍的發(fā)動(dòng)機(jī)。根據(jù)所用燃料，內(nèi)燃機(jī)還可分為汽油機(jī)、煤油機(jī)、柴油機(jī)等。 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 the vehicle. The actions taking place in the e

17、ngine cylinder can be classified into four stages, or strokes. Stroke refers to piston movement; a stroke occurs when the piston moves from one limiting position to the other. The upper limit of piston movement is called TDC (top dead center) .The lower limit of piston movement is called BDC (bottom

18、 dead center). A stroke is piston movement from TDC to BDC or from BDC to TDC. In other words, the piston completes a stroke each time it changes its direction of motion. 顧名思義，內(nèi)燃發(fā)動(dòng)機(jī)是在汽缸里燃燒燃料，將內(nèi)燃的膨脹力轉(zhuǎn)變成推動(dòng)汽車前進(jìn)的旋轉(zhuǎn)力。發(fā)動(dòng)機(jī)汽缸內(nèi)的工作過程可以分為四個(gè)過程或行程。(沖程)行程是指活塞的運(yùn)動(dòng)，即活塞從某一限定位置到另一限定位置的運(yùn)動(dòng)?；钊\(yùn)動(dòng)的上限稱為TDC(上止點(diǎn))，下限稱為BDC(下止點(diǎn))

19、。一個(gè)行程就是活塞從上止點(diǎn)到下止點(diǎn)，或從下止點(diǎn)到上止點(diǎn)的運(yùn)動(dòng)。換句話說，活塞每完成一個(gè)行程，就改變一次其運(yùn)動(dòng)的方向。 Where the entire cycle of events in the cylinder requires four strokes (or two crankshaft revolutions), the engine is called a four-stroke-cycle engine. The four-stroke-cycle engine is also called the Otto cycle engine, in honor of the Germa

20、n engineer, Dr. Nikolaus Otto , who first applied the principle in 1876. The four piston strokes are intake, compression, power and exhaust. Intake stroke. On the intake stroke, the intake valve has opened, the piston is moving downward, and a mixture of air and vaporized gasoline is entering the cy

21、linder through the valve port. The mixture of air and vaporized gasoline is delivered to the cylinder by the fuel system and carburetor. Compression stroke. After the piston reaches BDC, or the lower limit of its travel, it begins to move upward. As this happens, the intake valve closes. The exhaust

22、 valve is also closed, so that the cylinder is sealed. As the piston moves upward (pushed now by the revolving crankshaft and connecting rod), the air-fuel mixture is compressed. By the time the piston reaches TDC, the mixture has been compressed to as little as one-tenth of its original volume, or

23、even less. When the air-fuel mixture is compressed, not only does the pressure in the cylinder to up, but the temperature of the mixture also increases. Power stroke. As the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug. The ignition system delivers a

24、high-voltage surge of electricity to the spark plug to produce the spark. The spark ignites the air-fuel mixture. It now begins to bum very rapidly, and the cylinder pressure increases to as much as 35MPa or even more. This terrific push against the piston forces it downward, and a power impulse is

25、transmitted through the connecting rod to the crankpin on the crankshaft. The crankshaft is rotated as the piston is pushed down by the pressure above it. Exhaust stroke. As the piston reaches BDC again, the exhaust valve opens. Now, as the piston moves up on the exhaust stroke, it forces the burned

26、 gases out of the cylinder through theexhaust-valve port. Then, when the piston reaches TDC, the exhaust valve closes and the intake valve opens. Now, a fresh charge of air-fuel mixture will be drawn in to the cylinder as the piston moves down again toward BDC. This four stroke cycle of piston withi

27、n the cylinder is repeated time and again to put the vehicle forward. 發(fā)動(dòng)機(jī)汽缸中的全部工作過程分為四個(gè)沖程的(即曲軸旋轉(zhuǎn)兩周的)，叫做四沖程循環(huán)發(fā)動(dòng)機(jī)，或四循環(huán)發(fā)動(dòng)機(jī)。為紀(jì)念德國(guó)工程師尼科拉斯、奧托搏士于1876年首次運(yùn)用四行程循環(huán)原理，四行程循環(huán)發(fā)動(dòng)機(jī)也叫奧托循環(huán)發(fā)動(dòng)機(jī)。發(fā)動(dòng)機(jī)的四個(gè)活塞行程是進(jìn)氣、壓縮、做功和排氣。 進(jìn)氣沖程:在進(jìn)氣行程中，進(jìn)氣門打開，活塞向下移動(dòng)，可燃混合氣通過進(jìn)氣門進(jìn)入汽缸。適當(dāng)濃度的可燃混合氣是由燃料系統(tǒng)和化油器提供的。 壓縮沖程:在活塞到達(dá)下止點(diǎn)時(shí)或者是活塞下限時(shí)，活塞開始向上運(yùn)動(dòng)。同時(shí)，進(jìn)氣門

28、關(guān)閉，排氣門也關(guān)閉，所以這時(shí)的汽缸是封閉的。當(dāng)活塞向上運(yùn)動(dòng)時(shí)(這時(shí)是由轉(zhuǎn)動(dòng)的曲軸和連桿推動(dòng)活塞)，可燃混合氣被壓縮。當(dāng)活塞到達(dá)上止點(diǎn)時(shí)，可燃混合氣被壓縮到有原體積的十分之下甚至更少。當(dāng)油氣混合燃料被壓縮時(shí)，不僅汽缸里的壓力上升，可燃混合氣的溫度也隨之增加了。 做功沖程:當(dāng)活塞到達(dá)壓縮行程的上止點(diǎn)時(shí)，火花塞產(chǎn)生電火花。電火花是由點(diǎn)火系統(tǒng)向火花塞提供高壓電脈沖而產(chǎn)生的。電火花點(diǎn)燃可燃混合氣。可燃混合氣開始發(fā)生劇烈燃燒，汽缸內(nèi)壓力達(dá)到3-5兆帕，甚至更高。作用于活塞上強(qiáng)大的推動(dòng)力推動(dòng)活塞向下運(yùn)動(dòng)，并將這一推力通過連桿傳到曲軸上的連桿軸頸上。因此，當(dāng)活塞受壓向下運(yùn)動(dòng)時(shí)，推動(dòng)曲軸轉(zhuǎn)動(dòng)。 排氣沖程:當(dāng)活塞

29、再一次到達(dá)下止點(diǎn)時(shí)，排氣門打開。同時(shí)，活塞向上移動(dòng)，將廢氣經(jīng)排氣門排出汽缸。隨后，活塞達(dá)到上止點(diǎn)，排氣門關(guān)閉，進(jìn)氣門打開。當(dāng)活塞又一次向下移動(dòng)到達(dá)下止點(diǎn)時(shí)，新的可燃混合氣被吸入汽缸。 汽缸活塞的四個(gè)沖程不斷重復(fù)，推動(dòng)著汽車前進(jìn)。 The Power Mechanism of the Engine In a reciprocating engine, the power mechanism is called the crankshaft and connecting rod assembly. In this assembly, all of the major units such as t

30、he engine crankcase and cylinder block, the piston and connecting rod (see Figure 3.1), the crankshaft and flywheel work together to convert thermal energy into mechanical energy used to drive the vehicle. The engine crankcase and block are usually cast into one piece and therefore can be seemed as

31、the largest and most intricate piece of metal in automobile. They are usually made of high-grade cast alloy iron to improve wear characteristics of the cylinder. This major unit must be strong and rigid enough to withstand any bending or distortion. The piston converts the potential engines of the f

32、uel into the kinetic energy that turns the crankshaft. The piston is a cylindrical shaped hollow part that moves up and down inside the engines cylinder. The piston is composed of piston head, piston rings, piston lands, piston skirt and piston pin hole. The piston head or crown is the top surface a

33、gainst which the explosive force is exerted. It may be flat, concave, and convex or any one of a great variety of shapes to promote turbulence or help control combustion. In some application, a narrow groove is cut into the piston above the top ring to serve as a heat dam to reduce the amount of hea

34、t reaching the top ring. The piston rings carried in the ring groove are of two basic types: compression rings and off-control ring. The upper ring or rings are to prevent compression leakage; the lower ring or rings control the amount of oil being deposited on the cylinder wall. The lower groove or

35、 grooves often have holes or slots in the bottom of the grooves to permits oil drainage from behind the rings. The piston lands are parts of piston between the ring grooves. The lands provide a seating surface for the sides of piston rings. The main section of a piston is known as the skirts. It for

36、ms a bearing area in contact with the cylinder wall. The piston pinhole in the piston also serves as a bearing for the piston pin, which is used to connect the connecting rod. In addition, because pistons operate under exceedingly difficult mechanical and thermal conditions, piston must be strong en

37、ough to stand the force of the expansion, yet light enough to avoid excessive inertia forces when their direction of travel is reversed twice each revolution. Piston must be able to withstand the heat from the burning air-fuel mixture, plus the heat generated by friction. The connecting rod is attac

38、hed to the crankshaft at one end (big end) and to the piston at the other end (small end). In operation, the connecting rod is subjected to both gas pressure and inertia loads, and therefore, it must be adequately strong and rigid and light in weight as well. So they are generally fabricated from hi

39、gh quality steel. The connecting rod is in form of a bar with ring shaped heads at its end. They are composed of connecting rod small end, connecting rod shank, connecting rod big end, connecting rod cap, and connecting rod bearing half shells. Shank of the connecting rod is provided with an I-cross

40、 section to give the rod maximum rigidity with the minimum of weight. The big end of the rodis split so that it can be connected to the crankshaft. To avoid misplacing the rod caps during assembly, the connecting rods and their mating caps are marked on one side with serial numbers, starting with th

41、e first rod from the radiator, to identify their location in the engine. Some connecting rods have an oil spurt hole in the yoke or at the cap-mating surface to provide cylinder wall lubrication. The small end of the connecting rod is attached to the piston by a piston pin. In some cases the small e

42、nd of the rod is clamped to the pin or has a bushing in it to allow the pin and rod oscillation. In other designs the pin is bolted to the rod. Connecting rods are usually drilled to provide lubrication to the piston pin and also to spray oil into the bottom of the piston for piston cooling on some

43、designs. The crankshaft serves to change the reciprocating motion of the piston into rotary motion and handles the entire power output. The periodic gas and inertia forces taken by the crankshaft may cause it to suffer wear and bending and tensional strains. The crankshaft therefore must be adequate

44、ly strong and wear-resistant. So the crankshaft is either forged from a high quality steel or cast in a high-strong iron. The crankshaft is actually made up of various parts such as main bearing journals, rod journal, crank arm bearing, counter-balanced weight and flywheel end. The crankshaft revolv

45、es in bearings located in the engine crankcase, but the number of bearings used usually depends on the number of cylinders in the engine and the design of the engine. Mechanically, a crankshaft without special balanced weight would have severe vibration when revolving. In order to reduce or eliminat

46、e such vibration, it must be provided with counter balanced weights that extend radially from the crankshaft centerline in the opposite direction of the crank arms. In that way, the forces acting on the crankshaft are balanced and vibration is reduced. The rod journals are bored hollow in order to r

47、educe the crankshaft inertia. Drilled diagonally through the crank arms are oil holes to supply oil to the rod journals. The flywheel is a relatively heavy metal wheel, which is firmly attached to the crankshaft. Its function is to help the engine to run smoothly by absorbing some of the energy duri

48、ng the power stroke and releasing it during the other strokes. In the front face of the flywheel, there is a shallow indentation used to determine the position of the piston in the first cylinder. When this indentation is aligned with a special hole provided in the bell housing, the piston is at top

49、 dead center (TDC) or indicates the start of fuel injection into the first cylinder. The flywheels of some engines also carry marks indicating the serial numbers of the cylinders where the compression occurs. The flywheel marks and indentation are used for setting the valve and ignition systems rela

50、tive to prescribed positions of the crankshaft. In conclusion, the connecting rod and crankshaft mechanism of the engine is composed of various units, and each of these units has its own functions in producing power for vehicles. 發(fā)動(dòng)機(jī)的能量轉(zhuǎn)換裝置 曲柄連桿機(jī)構(gòu)就是往復(fù)式發(fā)動(dòng)機(jī)的能量轉(zhuǎn)換裝置。曲柄連桿機(jī)構(gòu)主要的組件，如曲軸箱和缸體、連桿和活塞、曲軸和飛輪，協(xié)同工作把

51、熱能轉(zhuǎn)化為機(jī)械能，從而推動(dòng)汽車行駛。 通常發(fā)動(dòng)機(jī)的曲軸箱和缸體澆鑄為了體。曲軸箱缸體是汽車中最大、最復(fù)雜的金屬件，一般由優(yōu)質(zhì)合金鑄鐵制成，以增強(qiáng)其耐磨性。(曲軸箱缸體)這個(gè)主要組件必須有足夠的強(qiáng)度和剛度，承受所有彎曲和扭曲變形。 活塞把燃料的內(nèi)能(化學(xué)能)轉(zhuǎn)化為動(dòng)能使曲軸旋轉(zhuǎn)。活塞是圓柱形的中空的機(jī)件，在汽缸內(nèi)上下運(yùn)動(dòng)?；钊身敳俊⒒钊h(huán)、環(huán)槽岸部、裙部和活塞銷組成?；钊敳炕蚬诙际腔钊纳媳砻妫?燃燒所產(chǎn)生的)爆炸作用力就作用于此。活塞頂部可以做成平的、凹的、凸的或是能夠促進(jìn)渦流幫助燃燒的任何形狀。某些發(fā)動(dòng)機(jī)中，最上道活塞環(huán)的上方開出一窄槽作為絕熱槽，以減少熱量的傳遞。位于活塞環(huán)槽內(nèi)的活塞環(huán)

52、分為氣環(huán)和油環(huán)。上面的(氣環(huán))防止漏氣，下面的(油環(huán))可以控制積聚在汽缸壁的機(jī)油量。活塞環(huán)槽內(nèi)通常鉆有油孔或油槽，以從活塞環(huán)后面泄油?；钊h(huán)槽之間的部位稱為槽岸，槽岸為活塞環(huán)側(cè)面提供了艾承面。 活塞最主要的部位是裙部，裙部形成活塞與缸壁的接觸支承面?；钊N座支撐活塞銷，而活塞銷連接活塞和連桿。此外，由于活塞在非?？量痰臋C(jī)械條件和很高的溫度下工作，其強(qiáng)度必須足以承受膨脹作用力。一個(gè)工作循環(huán)活塞上下運(yùn)動(dòng)兩次，因此活塞自重應(yīng)盡可能輕以減小慣性作用。活塞應(yīng)當(dāng)能夠承受燃燒混合氣和摩擦熱量。 連桿一端 (大頭)與曲軸相連，另一端 (小頭)和活塞配合。連桿工作時(shí)受到氣體壓力和慣性作用，因此必須有足夠的強(qiáng)度和

53、剛度，質(zhì)量盡可能輕。連桿一般由優(yōu)質(zhì)鋼制成，其桿身兩端為環(huán)形。連桿由小頭、桿身、大頭、連桿蓋和軸瓦組成。連桿桿身斷面為工字型，這樣可以同時(shí)獲得最大剛度和最小質(zhì)量。連桿大頭一般為剖分式，以便和曲軸相連。為防止裝配時(shí)裝錯(cuò)連桿蓋，在連桿和與其相配合的連桿蓋的某一側(cè)標(biāo)有序號(hào)，從靠水箱側(cè)為第一缸，以確認(rèn)各缸的位置。 一些連桿在大頭軸頭處或在連桿蓋配合面上鉆有噴油孔潤(rùn)滑汽缸壁。連桿小頭通過活塞銷與活塞相連。一些發(fā)動(dòng)機(jī)的連桿小頭與活塞銷夾在一起，即連桿小頭有襯套，使活塞銷和連桿一起運(yùn)動(dòng)。而在另一些設(shè)計(jì)中用螺栓連接活塞銷和連桿。通常連桿上鉆出油道潤(rùn)滑活塞銷，有些設(shè)計(jì)中連桿上的油道也向活塞底部噴油實(shí)現(xiàn)冷卻。 曲軸

54、用于把活塞的往復(fù)運(yùn)動(dòng)轉(zhuǎn)化為旋轉(zhuǎn)運(yùn)動(dòng)并控制全部動(dòng)力輸出。曲軸所受到的周期性的氣體壓力和慣性力導(dǎo)致曲軸磨損、產(chǎn)生彎曲和扭轉(zhuǎn)變形。因此曲軸應(yīng)當(dāng)有足夠的強(qiáng)度和耐磨。曲軸由優(yōu)質(zhì)鋼鍛造或通過高強(qiáng)度鑄鐵鑄造而成。事實(shí)上曲軸由主軸頸、連桿軸頸、曲柄臂軸承、平衡塊和飛輪端這些主要部件所組成。曲軸在位于曲軸箱內(nèi)的主軸承上旋轉(zhuǎn)，所使用的主軸承數(shù)量取決于發(fā)動(dòng)機(jī)汽缸數(shù)和發(fā)動(dòng)機(jī)的設(shè)計(jì)。如果沒有專門的平衡塊，曲軸在旋轉(zhuǎn)時(shí)會(huì)產(chǎn)生劇烈的振動(dòng)。為了減少甚至消除振動(dòng)，在曲軸中心線的延長(zhǎng)線上與曲柄臂相反方向配有平衡塊。這樣，作用于曲軸的作用力得到了平衡，減少了振動(dòng)。連桿軸頸內(nèi)部銳空目的是減少曲軸慣性。穿過曲柄臂斜向鉆出的油孔提供連桿

55、軸頸的潤(rùn)滑。 飛輪是一個(gè)相當(dāng)重的金屬輪盤，飛輪與曲軸緊相連。它的作用是在做功行程吸收能量，在其他工作行程釋放能量，從而有助于發(fā)動(dòng)機(jī)平穩(wěn)工作。 在飛輪前斷面有一淺的缺口，用來確定一缸活塞位置。當(dāng)缺口與飛輪殼體上的小孔對(duì)齊時(shí)，一缸活塞位于上止點(diǎn)或表明一缸開始噴油。有些發(fā)動(dòng)機(jī)的飛輪標(biāo)有在壓縮行程的汽缸序號(hào)。飛輪上的記號(hào)和缺口用來調(diào)整與曲軸特定位置相關(guān)的配氣機(jī)構(gòu)和點(diǎn)火系統(tǒng)。 總之，發(fā)動(dòng)機(jī)曲柄連桿機(jī)構(gòu)由各個(gè)不同的組件構(gòu)成，在產(chǎn)生汽車動(dòng)力時(shí)每個(gè)組件具有特定的功能。 Valves and Valve Train The valve gear of an internal combustion engine

56、provides timely admission of the fresh charge into the cylinders and exhaust of spent gases from them. For this purpose the valves at definite moments open and close the intake and exhaust ports in the cylinder head, through which the cylinders communicate with the intake and exhaust manifold. The v

57、alve gear is composed of timing gears, a camshaft, tappets, valves, spring with fasteners and valve guides. The timing gears in most engines are housed in a special case fitted at the front end of the engine. These are necessary to transmit rotation from the crankshaft to the camshaft, fuel injectio

58、n pump shaft, and to oil pump and other mechanisms.The gears are made of steel and use helical teeth to reduce noise. Camshafts function is to open the engine valves positively and timely, in a definite sequence, and to control their closing against the return action of the valve springs. The shaft

59、is made integral with its cams and bearing journals. Each cam controls a single valve, either intake or exhaust. In some automobile engines, the camshaft is made integral with fuel pump eccentric wheel and oil pump drive gear. The camshaft bearings are lubricated with oil supplied under pressure from the main gallery in the cylinder block. The tappets serve to transmit the force fr