《汽车构造（发动机）中英文ppt课件.ppt》由会员分享，可在线阅读，更多相关《汽车构造（发动机）中英文ppt课件.ppt（115页珍藏版）》请在三一办公上搜索。
1、STRUCTURE OF AUTOMOBILE ENGINE,汽车发动机构造,汽车运用教研组 黄银娣 开发,Chapter 1 :The Internal Combustion Engine,1-1 General Definition: The Internal Combustion engine VS The External Combustion Engine-The combustion(or burning) fuel takes place inside the engine. Fuel: 1. Most automobile engine produce power by bur
2、ning a mixture of air and gasoline ; 2. some kinds of engine by diesel fuel; 3. some by alternative fuels such as CNG（天然气）,LNG（液化石油气）,Methanol(甲醇）,ethanol(乙醇） and etc.,汽车运用教研组 黄银娣 开发 2003年8月,Main objection: To study the internal combustion engine,汽车运用教研组 黄银娣 开发 2003年8月,1-2 Gasoline as a fuel,know ab
3、out following points:NO.1 How the burning of gasoline produces mechanical power ? (1) Gasoline in liquid form is noncombustible(non-burning) (2) however,gasoline Vapor does burn ,combined with air(oxygen in air),gasoline vapor burns inside the engine to produce power.,汽车运用教研组 黄银娣 开发,NO.2 How does th
4、e liquid gasoline in the gas tank become gasoline vapor?,Evaporation: Gasoline becomes a vapor by evaporation ,which is the process of turning a liquid into a vapor.Gasoline begins to evaporate at a much lower temperature than water : T evaporation of gasoline T evaporation of water it means: Gasoli
5、ne is more easy to vaporize than water.,汽车运用教研组 黄银娣 开发,Evaporate,Evaporation takes place above the surface of a liquid when it is exposed to the air. -thus,gasoline vapor will fill the space above the surface of gasoline. lets have an experiment: see Fig.1-1Remember:there is always vapor above the s
6、urface of gasoline. While the liquid may not burn,the vapor will.,汽车运用教研组 黄银娣 开发,Atomized particles,Atomizer,1-1: the vapor made by a spray evaporates quickly.,汽车运用教研组 黄银娣 开发,Spraying the gasoline into the air,The best way to evaporate gasoline is to expose to the air as much of its surface as possi
7、ble-to make liquid gasoline into the tiny droplets.e.g Fig.12 The vapor made by a spray evaporates quickly.,汽车运用教研组 黄银娣 开发,fuse,Fuel-air mixture,stopper,1-2: In this experiment, gasoline vapor burning in a can has enough power to have the stopper out.,汽车运用教研组 黄银娣 开发 2003年8月,No.3 What happens when ga
8、soline evaporates?,The evaporating gasoline mixed with air.The evaporating gasoline expands to fill more space than it did as a liquid.If a flame is touched to this mixture, the gasoline vapor and air burn rapidly producing intense heat. When very hot, the mixture quickly expands even more.,汽车运用教研组
9、黄银娣 开发,No.4 What happens to the mixture when it is burned inside a closed container?,Fig.1-3Suppose:at the open end of a tin can -put a cork(塞子）； through the closed end -ran a fuse (引线，导火线） closed space filled with fuel-air mixture inside,汽车运用教研组 黄银娣 开发 2003年8月,Spark plug,Exhaust valve,Intake valve,
10、Combustion chamber,piston,cylinder,1-3: In this engine. A tight-fitting piston moves up and down in the cylinder. The intake valve takes in vapor. The exhaust valve releases the burned mixture.,汽车运用教研组 黄银娣 开发 2003年8月,Make an experiment:,First: sprayed in a mixture of vaporized gasoline and air with
11、atomizer.Second: lit the fuse Then :the fuse will ignite the gasoline vapor.The last : the burning vapor would expand with such force that it would blow the stopper off -thats “explosion”conclusion:Internal combustion engine burns gasoline vapor and air to produce power.,汽车运用教研组 黄银娣 开发,1-3 A One-cyl
12、inder Internal Combustion engine,The tin can - Like the cylinder of engine The stopper in the tin can -Like a piston The fuse in the tin can -Like a spark plug Space between the top of the piston and the top of the cylinder.-The combustion chamber,汽车运用教研组 黄银娣 开发,Intake valve -the mixture is let in a
13、nd ignitedExhaust valve-exhaust gas was released from the cylinder through the exhaust valveCrankshaft(曲轴）-looks like a straight bar with an offset(n.偏置）section in the center of it (crankshaft) function: to change pistons up and down motion to the rotation of the crankshaft A connecting rod-joins th
14、e piston and the crankshaft,Piston,Connecting rod,crankshaft,1-4: the crankshaft is straight, with an offset section in the middle of it. It is joined to the piston moves the crankshaft. This converts the vertical motion of the piston into the rotary motion of the crankshaft.,汽车运用教研组 黄银娣 开发,1-5 Bore
15、 and stroke,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发 2003年8月,1-6 piston strokes,Intake stroke ( 进气行程)Compression stroke ( 压缩行程)Power stroke ( 做功行程)Exhaust stroke ( 排气行程),汽车运用教研组 黄银娣 开发,第二节 四冲程发动机工作原理,四冲程柴油机 工作过程,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发 2003年8月
16、,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发,汽车运用教研组 黄银娣 开发,汽车运用教研组 黄银娣 开发,汽车运用教研组 黄银娣 开发,1-7 engine displacement,汽车运用教研组 黄银娣 开发 2003年8月,汽车运用教研组 黄银娣 开发,Compression ratio,Compression ratio is a comparison between the volume in the cylinder when the piston stands at BDC against the vo
17、lume at TDC. =Va/Vc car(gasoline): 8:1-11:1; some racing car :13:1-14:1,汽车运用教研组 黄银娣 开发,汽车运用教研组 黄银娣 开发,Review question,1. Why must gasoline be vaporized in an engine?2.Where is the air-fuel mixture ignited?3.What does the abbreviation TDC stand for?4.what is the final strokes in an engine cycle?5.lis
18、t the four engine strokes.6.how is displacement measured?7.how do you calculate compression ratio?,汽车运用教研组 黄银娣 开发,CH2:Engine fundamentals,21 Engine systems,22 Engine configuration the in-line engine,The way to arrange cylinders in a group is to line them up in a straight row.Usually have even number
19、 (four,six, eight line cylinders,its balanced.But sometime have 3or 5 cylinders.,21：An example of an in-line engine that has four cylinders in a line.,The V-type engine,The V-8 engine was designed to produce the power of the in-line eight in a smaller engine.Has two four-cylinder in-line engines pla
20、ced beside each other in the shape of a V Has only one crankshaft ,with all eight cylinders connected. In the United States,it was for years the moat popular engine. Today ,there are V-4 engine just two cylinder long ;V-6 type ;V-8,even some expensive foreign cars have V-12 engines,which have two ba
21、nk of six cylinders each.,2-2: Auto manufactures make V-type engines of four, six, and eight cylinders. A V-6 configuration is shown here.,2-3: the horizontally-opposed engine has two banks of cylinders pointing in opposite directions. Because the banks have a 180 angle between them, this engine is
22、called a flat engine.,The flat engine,See Fig.2-3It has two banks of cylinders opposite one another .Just like the V-type become a flat horizontal line.Eg. Air-cooled Volkswagens(大众） use the flat-four engine. Many Porsches use the flat-six.,23 Engine placement,发动机驱动：Front engine,rear wheel drive(tru
23、ck,jeep etc.)Rear engine,rear wheel drive(Passenger cars)Front engine,front wheel drive(most car)发动机位置：In-line power train（纵向发动机）:the engine is centered and the shafts run the length of the car.（与车轴垂直）Transverse engine(横向发动机）:the engine is crosswise in the car. In this case ,the engine is right over
24、 the front axle. Which it drives. A car with such a design has a transverse engine.（与车轴平行),A,B,Engine,Engine,Drive shaft,Driving axle,Driving axle,2-4: (A)Many cars have an in-line engine arrangement with the engine and drive shaft running front-to-rear. (B)In transverse engine arrangement the engin
25、e runs from side to side.,24 The engine system the fuel system,As show in Fig.2-5Function : the fuel system stores fuel and delivers it to the engine as needed.Composition:four basic parts make up the fuel system. They are the fuel tank ,fuel lines,fuel pumps and the fuel filter.,Fuel tank,Fuel line
26、,Fuel pump,Fuel filter,2-5: The fuel system stores the fuel and delivers it to the engine as needed.,25The intake system,See Fig.2-6Function: takes fuel from the fuel system,mixes it with just the right amount of air, and then delivers it to the combustion chamber.Composition: the air cleaner, the a
27、ir filter,the carburetor,the intake manifold, the intake parts etc.,Air cleaner,Air filter,carburetor,Intake manifold,block,2-6: the main parts of the intake system.,26 The ignition system,See fig.2-7Function: the ignition system ignites (or fires) the air-fuel mixture in the combustion chamber at j
28、ust the right instant.this instant is at the end of the compression stroke and the beginning of the power stroke. Unless the fuel is ignited at the correct moment,the engine will not run properly.Composition : battery,spark plugs, the coil, and the distributor etc.,Coil wire,battery,Coil,Spark plug
29、wires,distributor,Spark plugs,2-7: the ignition system takes electricity from the battery and delivers it to the spark plugs to ignite the fuel-air mixture.,27 the cooling system,See fig.2-8,2-9Function: to carry away the heat produced by the combustion engine inside the chamber.Types: a. the air-co
30、oled engine（风冷发动机）(most motorcycle) b.and the water cooled engine （水冷发动机）(most cars)The water cooled:also called liquid-cooled . a mixture of water and a chemical，the liquid prevents freezing in the winter and boiling in the summer. the chemical: is antifreeze (防冻剂）(its scientific name is ethylene g
31、lycol),air,air,fan,Cooling fins,2-8: An air-cooled engine uses the outside air passing over the engine to carry away the heat produced by the burning mixture.,Water jacket,Water pump,coolant,radiator,2-9: A water-cooled engine uses a liquid to cool the engine. Then it uses air to cool the liquid.,28
32、The lubrication system,See Fig.2-10,11Parts of the lubrication system :1.The oil pan (油底壳）: is the holder ,or sump ,for the 3-6qts.(about 3-5L)of oil .2.an oil pump （油泵）:draws the oil from the pan and pushes it through the oil filter.3.the oil filter（滤清器）:removes dirt from the oil .4.oil galleries(油
33、道）：passages the oil through in the engine parts that need lubrication.,Pushing force,force of friction,2-10 : friction is the force that resists motion between two surfaces in contact.,Oil galleries,Oil pan,Oil pick up,Oil pump,Oil filter,2-11: the lubrication system provides oil to all internal eng
34、ine parts, to reduce heat inside the engine.,29 The exhaust system(排气系统）,Function:takes the burned gases from the cylinder,carries them away from the engine,and discharges them into the air.See fig. 2-12Parts of the exhaust system: exhaust manifold （排气歧管）,exhaust pipe（排气管） ,intermediate pipe（中间排气管）,
35、muffle（消声器）,and tail pipe（排气尾管） .,Tail pipe,muffler,Intermediate pipe,Exhaust pipe,Exhaust manifold,2-12: the exhaust system Carries the burned gases away from the engine and out into the air. It also lessens the loud noise produced by the engine.,Review questions,1.What is engine configuration?2.wh
36、at is a horizontally-opposed engine(水平对置，平置发动机）?3.list the six engine systems.4.What is a transverse engine(横置发动机）?5.what does the distributor do?6.why is liquid cooling needed in modern engines?7.why is oil needed in an engine?,Chapter 3: engine blocks and cylinder heads（发动机机体和汽缸盖）,See fig.3-1,Inta
37、ke manifold,distributor,Piston and rod,crankshaft,block,Oil pan,Water pump,Cylinder head,Head cover,3-2: the block is the main support piece for the engine. All other engine parts fit inside the block or fasten to it.,The engine block,Engine block is the basic frame of the engine. All other engine p
38、arts either fits inside it or fasten to it. It holds the cylinders（汽缸),water jackets(水套）, and oil galleries(油道）；It also holds the crankshaft,which fastens to the bottom of the block. The camshaft also fits inside the block,except on overhead-cam engine(OHC)(顶置式凸轮轴）。In the most cars,the block is made
39、 of gray iron(灰铁）,or an alloy（合金）(mixture)of gray iron and other metals,such as nickel （镍）or chromium（铬）.Engine blocks are castings（铸造). A casting is produced by heating metal until it becomes a liquid and then pouring it into a mold(模子) ,where it hardens into the correct shape.Some engine blocks in
40、 the small cars,are made of cast aluminum(铸铝），this metal is lighter than the iron.however ,iron wears better than aluminum.therefore, the cylinders in most aluminum engine are lined with iron or steel sleeves(衬套）。This sleeves are called cylinder liners or cylinder sleeves.(缸套）Some blocks are made en
41、tirely of aluminum.,Cast iron block,aluminum block,sleeves,3-3: the engine block is made of cast iron or cast aluminum. In most aluminum engines, the cylinders are lined with iron or steel.,The cylinder head,See fig.3-2,the cylinder head fastens to the top of the block, just as a roof fits over a ho
42、use. The head is the width and length of the block. Most cylinder heads are made of cast iron,though some are of cast aluminum.,in some engines,the block and the cylinder head are made of different materials.See fig.3-4,v-8 engine has two cylinder heads,each bank have four cylinders.,Head,Head,block
43、,block,block,V-8,In-line four,Flat four,3-4: the number of cylinder heads on an engine depends on the number of banks of cylinders it has, Each bank requires one head.,Combustion chamber,Oil and water passages,Valve sets,Exhaust ports,Pushrod guide holes,Valve guides,Spark plug Holes,Intake ports,3-
44、5: the underside of the head has pockets for the top of the combustion chamber. The top of the head contains valve seats and rocker stands.,Rocker shaft,Head bolt hole,Valve spring,Rocker arm,port,Pushrod guide hole,valve,3-6: A fully assembled cylinder head has many parts.,fins,Head surface,Head su
45、rface,Block deck,Block deck,gasket,No gasket,3-8: pressed between two surfaces, a gasket fills in the irregularities and provides a tight seal.,3-7: an air-cooled head has fins but no water jacket passages.,Bolt holes,Oil passage holes,Water passage holes,Cylinder holes,bolt holes,3-9: the head gask
46、et has holes cut in to fit the holes in the deck and head surfaces. Once a head gasket is removed, you should replace it with a new one.,Valve cover,Exhaust manifold,head,carburetor,Intake manifold,3-10: the valve cover, exhaust manifold, and intake manifold are fastened to the cylinder head.,carbur
47、etor,Intake manifold,head,head,Exhaust manifold,Litter valley,Exhaust manifold,Timing cover,Oil pan,block,Oil pan,3-11: A single intake manifold fits into the central part of a V-8 engine, covering the lifter valley. An exhaust manifold bolts to the outside of each head.,3-12: the oil pan and the ti
48、ming cover.,hemi,wedge,Semi-Hemi,hemi,wedge,Semi-Hemi,3-13: the three most common types of automobile engine head are the hemi,wedge, and semi-hemi.,front,Front of car,front,front,flywheel,flywheel,flywheel,flywheel,rear,rear,Front of engine,Back of engine,Steering wheel,left,right,3-14:,3-15:,3-16:
49、,3-17:,Review question,1. What is a casting?2. Why is a cylinder head needed?3. Where are the intake and exhaust ports located?4. How is the cylinder head sealed to the block?5. What are the three most common cylinder head shapes?6.list the major parts that are fastened to the block?,Chapter 4: Conn
50、ecting rods, bearings, and crankshafts,连杆,轴瓦.曲轴Connecting rods link the piston to the crankshaft . these rods convert the reciprocating (up-and-down) motion of the piston into the rotary motion of the crankshaft .fig.4-1 . The connecting rods are protected by bearings.,4-1: the connecting rod links
