发动机类外文文献翻译(中文)

1 SummarizeOutline uses a more compact design along with the engine and has in a big way, the engine produces the waste heat density also obviously increases along with it. Some essential regions, if around a row of tyre valve radiates the question to have first to consider, the cooling system even if appears the small breakdown also possibly to create the disaster in such region consequence. The engine cooling system radiation ability generally should satisfy when the engine full load radiation demand, because this time engine produces the quantity of heat is biggest. However, when partial loads, the current capacity which the cooling system can have the power loss, which the water pumping station provides the refrigerant current capacity surpasses needs. We hoped starts the starting time to be as far as possible short. Because engine time discharges pollutant more, the oil consumption is also big. The cooling system structure has a more tremendous influence to the engine cold starting time.2 Characteristics of modern engine cooling systemModern engines series characteristic tradition cooling system function reliably protects the engine, but also should have the function which the improvement fuel economy and reduces discharges. Therefore, the modern cooling system must synthesize under the consideration the factor: Engine interior friction loss; Cooling system water pump power; Burning boundary condition, like combustion chamber temperature, complete density, complete temperature. The advanced cooling system uses systematized, the modular design method, the overall plan considered each influence factor, causes the cooling system both to guarantee the engine normal work, and enhances the engine efficiency and the reduction discharges.2.1 The temperatures set point Temperatures hypotheses firing in bursts motive operating temperature limit value are decided by a row oftire valve the peripheral region maximum temperature. The most ideal situation is according to the metal temperature but is not the refrigerant temperature control cooling system, like this can protect the engine well. Because the cooling system hypothesis cooling temperature is by the full load time most is big is the foundation, therefore, engine and cooling system in partial loads time is at not too the perfect condition, when urban district travel and low speed travel, can have the high oil consumption and discharge. Supposes the fixed point through the change refrigerant temperature to be possible to improve the engine and the cooling system in partial loads time performance. According to a row of tyre valve the peripheral region temperature limit value, may elevate either reduce the refrigerant or the metal temperature supposes the fixed point. Elevates or reduced temperature all respectively has the characteristic, this is decided the goal which achieved to the hope.2.2 Enhances the temperature Enhances the temperature to suppose the fixed-point enhancement operating temperature to suppose the fixed point is one kind of comparison the method which welcome. Enhances the temperature to have many merits, it directly affects the engine loss and the cooling system effect as well as the engine discharging formation. Will enhance the operating temperature to enhance the engine Mac reduce the engine to rub wears, reduces the engine fuel oil consumption. The research indicated that, the engine operating temperature to rubs the loss to have the very tremendous influence. Discharges the temperature the refrigerant to enhance to 150 ℃, causes the cylinder temperature to elevate to 195 ℃, the oil consumption drops 4%-6%. Maintains the refrigerant temperature in 90-115 ℃ scope, causes the engine machine oil the maximum temperature is 140 ℃, then oil consumption in partial loads time drops 10%. Enhances the operating temperature also obvious influence cooling system the potency. Enhances the refrigerant or the metaltemperature can improve the engine and disperse the steam heat transfer transmission the effect, reduces the refrigerant the speed of flow, reduces the water pump the rated power, thus reduces the engine the power dissipation. In addition, may select the different method, further reduces the refrigerant the speed of flow.2.3 Reduce the temperatures set point Reduced temperatures suppose the fixed point to reduce the cooling system the operating temperature to be possible to enhance the engine charge efficiency, reduces the inlet temperature. This to the combustion process, the fuel oil efficiency and discharges advantageously. The reduced temperature supposes the fixed point to be allowed to save the engine movement cost, enhances the part service life. The research indicated, if the cylinder head temperature reduces to 50 ℃, the ignition angle of advance may 3 ℃ A but not have the engine knock ahead of time, the charge efficiency enhances 2%, the engine operational factor improvement, is helpful to the optimized compression ratio and the parameter choice, obtains the better fuel oil efficiency and discharges the performance.2.4 Precise cooling system Precise cooling systems precise cooling system mainly manifests in the cooling jacket structural design and in the refrigerant speed of flow design. In precise cooling system, hot essential area, if around a row of tyre valve, the refrigerant has an greater speed of flow, the heat transfer efficiency is high, the refrigerant gradient of temperature changes slightly. Such effect comes from to reduce these place refrigerant channels the lateral section, enhances the speed of flow, reduces the current capacity. The precise cooling system design key lies in the determination cooling jacket the size, the choice match cooling water pump, guaranteed the system the radiation ability can satisfy when the low speed big load essential region operating temperature demand. The engine refrigerant speed of flow rangeof variation is quite big, from time 1 m/s to maximum work rate time 5 m/s. Therefore should considered the cooling jacket and the cooling system whole that, mutually supplemented, display biggest potential. The research indicated that, uses the precise cooling system, in the engine entire work rotational speed scope, the refrigerant current capacity may drop 40%. Covers the cooling jacket to the air cylinder the precise design, may make the ordinary speed of flow to enhance from 1.4m/s to 4 m/s, greatly enhances the cylinder cover or cap thermal conductivity, cylinder cover or cap metal temperature drop to 60 ℃.2.5 Divergences types cooling system Divergences types cooling system divergence type cooling system for other one kind of cooling system. In this kind of cooling system, the hine oil temperature, will cylinder cover or cap friendly cylinder body cools by respective return route, the cylinder cover or cap friendly cylinder body has the different temperature. The divergence -like cooling system has the unique superiority, may cause engine each part to suppose the fixed-point work at the most superior temperature. The cooling system overall efficiency achieves in a big way. Each cooling return route will suppose under the fixed point or the speed of flow in the different cooling temperature works, will create the ideal engine temperature distribution. The ideal engine hot active status is the cylinder head temperature lower but the air cylinder body temperature relative is higher. The cylinder head temperature is lower may enhance the charge efficiency, increases. The temperature is low also greatly may promote completely to burn, reduces CO, HC and the NOx formation, also enhances the output. The higher air cylinder body temperature can reduce the friction to lose, directly improves the fuel oil efficiency, indirectly reduces in the cylinder the peak value pressure and the temperature. The divergence type cooling system may cause the cylinder cover and the cylinder body temperaturediffers 100 ℃. The cylinder temperature may reach as high as 150 ℃, but the cylinder cover temperature may reduce 50 ℃, reduces the cylinder body to rub loses, reduces the oil consumption. The higher cylinder body temperature causes the oil consumption to reduce 4%-6%, when partial loads HC reduces 20%-35%. When the damper all opens, the cylinder cover and the cylinder body temperature supposes the definite value to be possible to move to 50 ℃ and 90 ℃, improves the fuel oil consumption, the power output from the whole and discharges.2.6 Controllable cooling system Controllable engine cooling system tradition engine cooling system belongs to the passive form, the structure simple or the cost is low. The controllable cooling system may make up at present cooling system the insufficiency. Now the cooling system design standard solves time the full load radiation problem, thus partially shoulders time the oversized radiation ability will cause the engine power waste. This to the light vehicle said especially obvious, these vehicles majority time all under the partial loads go in the urban district, only uses the partial engine power, causes a cooling system higher loss. In order to solve the engine to get down the hot question in the peculiar circumstance, the present cooling system volume was bigger, causes the evaporation efficiency to reduce, has increased the cooling system power demand, lengthened the engine during warm machine-hour. The controllable engine cooling system generally includes the sensor, the execution and the electrically controlled module. The controllable cooling system can act according to the engine working condition adjustment cooling quantity, reduces the engine power loss. In the controllable cooling system, the execution for the cooling water pump and the thermostat, generally and the control valve is composed by the electrically operated water pump, may act according to requests to adjust the cooling quantity. Temperature sensor for a system part, but rapidly bequeaths the engine hot conditionthe controller. Controllable installment, if the electrically operated water pump, may suppose the temperature the fixed point from 90 ℃ to enhance to 110 ℃, saves 2%-5% fuel oil, CO reduces 20%, HC reduces 10%. When steady state, the metal temperature ratio tradition cooling system is high 10 ℃, the controllable cooling system has the quicker response ability, may cool the temperature to maintain is supposing the fixed point ±2 ℃ the scope. From 110 ℃ drops to 100 ℃ only needs 2 s. The engine during warm machine-hour reduces 200s, the cooling system operating region draws close to the work limit region, can reduce the engine cooling temperature and the metal temperature undulation scope, reduces circulates the fatigue of metal which the hot load creates, lengthens the component life.3 ConclusionIn front of 3 conclusions introduced several kind of advanced cooling systems have the improvement cooling system performance the potential, can enhance the fuel oil efficiency and discharge the performance. The cooling system can control the nature is improves the cooling system the key, can the controlling expression to the engine structure protection essential parameter, like the metal temperature, the refrigerant temperature and the machine oil temperature and so on can control, guarantees the engine to work in the safety margin scope. The cooling system can make the rapid reaction to the different operating mode, the most earth saves the fuel, reduces discharges, but does not affect the engine overall performance. Looked from the design and the operational performance angle that, divergence type cooling and precise cooling unifies has the very good prospects for development, both can provide the ideal engine protection, and can enhance the fuel oil efficiency and discharge the nature. This kind of structure is advantageous to forming the engine ideal temperature distribution. Directly to a cylinder coveror cap row of tyre valve around the supplies refrigerant, reduced the cylinder head temperature change, causes the cylinder cover temperature distribution to be evener, also can maintains the machine oil and the cylinder body temperature at the design operating region, has a lower friction to damage the pollution withdrawal. method as follows: 1st, the cooling system function, is part of quantity of heats which absorbs the engine part carries off, guaranteed the diesel engine various components maintain in the normal temperature range. cooling system function and maintenance maintenance2nd, the cooling water should be does not contain dissolves the Xie salt the soft water, like clean river water, rain water and so on. Do not use hard water and so on the well water, water seepage or sea water, guards against produces, causes the engine to radiate not good, question occurrence and so on air cylinder heat.3rd, with the funnel when joins the cooling water the water tank, must prevent the water splashes to on the engine and the radiator, prevented on the radiator fin and the organism accumulates the dust, smears, affects the cooling effect.4th, if when the engine lacks the water causes the hyperpyrexia, cannot immediately add water, should cause the engine idling speed to revolve 10 □15 minutes, after the uniform temperature slightly reduces, slowly does not join the cooling water in the engine situation.5th, the winter, the water tank planted agent adds the hot water. After the start should surpass 40 degree-hour the slow revolution to the water temperature to be able to work. After the work had ended, must put the completely cooling water.6th, must regularly eliminate in the water tank, must frequently scour the sludge to the forced-air cooling engine radiator fin, dirty is filthy. The radiator fin cannot damage, after if damages must promptlyreplace, in order to avoid influence radiation effect.4 LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuouslyvariable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances,but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.5 Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of 0.003 (three-thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are knownas the limits. The difference between upper and lower limits is called the tolerance.1 概述随着发动机采用更加紧凑的设计和具有更大的比功率，发动机产生的废热密度也随之明显增大。

General comments of automobile engineEngine is the source of far, automotive engines are all powered by heat except for a few of automotives drived by automotive engines are called internal combustion engines because fuel burns inside the engine .The engine converts the burning fuel’s thermal energy to mechanical energy.By Cooling Systems Liquid-cooled engines and air-cooled engines are being used .Liquid-cooled engines are the most common in the diesel industry .By Fuel System Gasoline diesel and propane fuel systems are currently used in a wide variety of engines .By Ignition Method Gas engines use the spark (electrical)ignition diesel engines use the heat fro BDC to TDC ;it varies with cylinder bore size ,length of piston stroke ,and numb system injection .The calory of diesel engine come from the fuel emblazed by the compressed diesel engine’compression ration is much bigger than the gas sufficient calory is from the fuel burned by the pressed air.By valve Arrangement Four types of valve arrangements have been used in gasoline and diesel engines .Of the four types (L, T ,F ,and I heads ),the I head is commonly used on diesel engines .By Cylinder Arrangement Engine block configuration or cylinder arrangement depends on cylinder block design .Cylinders may be arranged in a straight line one behind the other .The most common in-line designs are the four-and six-cylinder engines .The V type of cylinder arrangement uses two banks of cylinders arranged in a 60°to 90°V design .The most common examples are those with two banks of three to eight cylinders each .The opposed engine uses two banks of cylinders opposite each other with the crankshaft in between .Engine’classificationAccording to the differences of the piston’movement, the piston intenal combusition engine will be classified reciprocating intenal combusition engine and rotary piston intenal combusition we will introduce working principle diagram of reciprocating internal combustion engine.Except for the wankel rotary ,engine ,all production automotive engines are the reciprocating ,or piston ,design . Reciprocating means “up and down “ or “back and forth“ .It is this up-and-down action of a piston in a cylinder that gives the reciprocating engine its name .Almost all engines of this type are built upon a cylinder block ,or engine block .The block is an iron or aluminum casting that contains the engine cylinders .The top of the block is covered with the cylinder head ,which forms the combustion chambers .The bottom of the block is covered with an oil pan ,or oil sump .A major exception to this type of engine on struction is the air-cooled V olkwagen engine .It is representative of the horizontally opposed air-cooled engines used by Porsche ,Chevrolet (Corvair ) ,and some other automobile manufacturers in years past .Power is produced by the inline motion of a piston in a cylinder .However ,this linear motion must be changed to rotating motion to turn the wheels of a car or truck .The piston is attached to the top of a connecting rod by a pin ,,called a piston pin or connecting rod transmits the up-and –down motion of the piston to the crankshaft ,which changes it to rotating motion .The connecting rod is mounted on the crankshaft with large bearings called rod bearings .Similar bearings , called main bearings ,are used to mount the crankshaft in the block.The crankshaft changes the reciprocating motion of the pistons to rotating motion .The combustible mixture of gasoline and air enters the cylinders through valves .Automotive engines use poppet valves .The valves can be in the cylinder head or in the block .The opening and closing of the valves is controlled by a camshaft .Lobes on the camshaft push the valves open as the camshaft rotates .A spring closes each valve when the lobe is not holding it open .The most common arrangements of engine cylinders and valves are discussed later .The basic single-cylinder engine consists of a cylinder (engine block ),a movable piston inside this cylinder ,a connecting rod attached at the top end to the piston and at the bottom to the offset portion of a crankshaft ,a camshaft to operate the two valves (intake and exhaust ), and a cylinder head .A flywheel is attached to one end of the crankshaft .The other end of the crankshaft has a gear to drive the camshaft gear .The camshaft gear is twice as large as the crankshaft gear .This drives the camshaft at half the speed of the crankshaft on four-stroke-cycle engines ,the crankshaft and camshaft run at the same speed .Energy ConversionThe internal combustion diesel engine is a device used to convert the chemical energy of the fuel into heat energy and then convert this heat energy into usable mechanical energy .This is achieved by combining the appropriate amounts of air andfuel and burning them in an enclosed cylinder at a controlled rate .A movable piston in the cylinder is forced down by the expanding gases of combustion .The movable piston in cylinder is connected to the top of a connecting rod .The bottom of the connected rod is attached to the offset portion is transferred to the crankshaft ,As the piston is forced down ,this offset portion of a crankshaft ,to rotate .The reciprocating (back and forth or up and down )movement of the piston is converted to rotary (turning )motion of the crankshaft ,which supplies the power to drive the vehicle .In general an average air-fuel ratio for good combustion is about 15parts of air to 1 part of fuel by weight .However ,the diesel engine always takes in a full charge of air (since there is no throttle plate in most systems ) ,but only a small part of this air is used at low or idle engine speeds .Air consists of about 20 percent oxygen while the remaining 80 percent is mostly nitrogen .This means that ,for every gallon of fuel burned ,the oxygen in 9,000 to 10,000gallons of air is required .Four-Stroke CycleGasoline by itself will not burn ,it must be mixed with oxygen (air ) .This burning is called combustion and is a way of releasing the energy stored in the air-fuel mixture .To do any useful work in an engine ,the air-fuel mixture must be compressed and burned in a sealed chamber .Here the combustion energy can work on the movable piston to produce mechanical energy .The combustion chamber must be sealed as tightly as possible for efficient engine operation .Any leakage from the combustion chamber allows part of the combustion energy to dissipate without adding to the mechanical energy developed by the piston movement .The 4-stroke engine is also called the Otto cycle engine ,in honor of the German engineer ,Dr. Nikolaus Otto ,who first applied the principle in 1876 .In the 4-stroke engine ,four strokes of the piston in the cylinder are required to complete one full operating cycle :two strokes up and two strokes down .Each stroke is named after the action it performs-intake ,compression ,power ,and exhaust :1、Intake Stroke As the piston moves down ,the vaporized ,mixture of fuel ;and air enters the cylinder past the open intake valve .2、Compression Stroke The piston returns up ,the intake valve closes ,the mixture is compressed within the combustion chamber ,and ignited by a spark .3、Power Stroke The expanding gases of combustion force the piston down in the cylinder .The exhaust valve opens near the bottom of the stroke .4、Exhaust Stroke The piston moves back up with the exhaust valve open ,and the burned gases are pushed out to prepare for the next intake stroke .The intake valve usually opens just before the top of the exhaust stroke .This 4-stroke cycle is continuously repeated in every cylinder as long as the engine remains running .Two-Stroke-CycleThe two-stroke-cycle diesel engine completes all four events:intake,compression, power ,and exhaust. in one revolution of the crankshaft or two strokes of the piston .A series of ports or openings is arranged around the cylinder in such a position that the ports are open when the piston is at the bottom of its stroke .A blower forces air into the cylinder through the open ports .expelling all remaining exhaust gases past the open exhaust valves and filling the cylinder with air .This is called scavenging .As the piston moves up ,the exhaust valves close and the piston covers the ports .The air trapped above the piston is compressed ton covers the ports .The air trapped above the piston is compressed since the exhaust valve is closed .Just before the piston reaches top dead center ,the required amount of fuel is injected into the cylinder .The heat generated by compressing the air ignites the fuel almost immediately .Combustion continues until the fuel injected has been burned .The pressure resulting from combustion forces the piston downward on the power stroke .When the piston is approximately falfway down ,the exhaust valves are opened ,allowing the exhaust gases to escape .Further downward movement uncovers the inlet ports ,causing fresh air to enter the cylinder and expel the exhaust gases .The entire procedure is then repeated ,as the engine continues to run .The differences of the two intenal combustion engineIt could be assumed that a two-cycle engine with the same number of cylinders ,the same displacement ,compression ratio ,and speed as a four-cycle engine would have twice the power since it has twice as many power .However ,this is not the case ,since both the power and compression strokes are shortened to allow scavenging to take place .Thetwo-cycle engine also requires a blower ,which takes engine power to drive .About 160 degrees out of each 360 degrees of crankshaft rotation are required for exhaust gas expulsion and fresh air intake (scavenging )in a two-cycle engine .About 415 degrees of each 720 degrees of crankshaft rotation in a four-cycle engine are required forintake and exhaust .These figures indicate that about % of crank rotation is used for the power producing events in the two-cycle engine ,while about 59% of crank rotation is used for these purposes in the four-cycle engine .Friction losses are consequently greater in the four-cycle engine .Heat losses ,however ,are greater in the two-cycle engine though both the exhaust and the cooling systems .In spite of these differences ,both engine types enjoy prominent use worldwide .Engine constructionCylinder Block:The cylinder block is cast in one piece. Usually, this is the largest and the most complicated single piece of metal in the automobile.The cylinder block is a complicated casting made of gray iron (cast iron ) or aluminum. It contains the cylinders and the water jackets that surround them. To make the cylinder block, a sand form called a mold is made. Then molten metal is poured into the mold. When the metal has cooled the sand mold is broken up and removed. This leaves the tough cylinder-block casting. The casting. The casting is then cleaned and machined to make the finished block.Cylinder blocks for diesel engines are very similar to those for spark-ignition engines. The basic difference is that the diesel-engine cylinder block is heavier and stronger. This is because of the higher pressures developed in the diesel-engine cylinders.Several engines have aluminum cylinder blocks. Aluminum is relatively light metal, weighing much less than cast iron. also ,aluminum conducts heat more rapidly than cast soft to use as cylinder wall material. It wears too rapidly. Therefore, aluminum cylinder blocks must have cast-iron cylinder liners or be cast from an aluminum alloy that has silicon particles in it.Some manufactures make an aluminum cylinder block that does not have cylinder liners, or sleeves. Instead ,the aluminum is loaded with silicon particles. Silicon is a very hard material. After the cylinder block is cast, the cylinders are honed. Then they are treated with a chemical that etches eats away, the surface aluminum. This leaves only the silicon particles exposed. the piston and rings slide on the silicon with minimum wear. Piston:The piston converts the potential energy of the fuel into the kinetic energy that turns the crankshaft. The piston is a cylindrical shaped hollow part that moves up and down inside the engine’s cylinder. It has grooves around its perimeter near the top where thering are placed. The piston fits snugly in the cylinder. It has grooves around its perimeter near the top where the rings are placed. The piston fits snugly in the cylinder. The pistons ate used to ensure a snug “air tight” fit.The piston in your engine’s cylinder are similar to your legs when you ride a bicycle. Think of your legs as pistons; they go up and down on the pedals, providing power. Pedals are like the connecting rods; they are “attached”to your legs. The pedals are attached to the bicycle crank which is like the crank shaft, because it turns the wheels.To reverse this, the pistons (legs) are attached to the connecting rods ( pedals ) which are attached to the crankshaft (the bicycle rank). The power from the combustion in the cylinders powers the from the combustion rods to turn the crankshaft. Connecting rod：The connecting rod shown in is made of forged high strength steel. It transmits force and motion from the piston to the crank pin on the crankshaft. A steel piston pin, or “wrist pin”, connects the small end of the connecting rod. Some rods have a lock bolt in the small end. As the piston moves up and down in the cylinder, the pin rocks back and forth in the hole, or bore, in the piston. The big end of the connecting rod is attached to a crank pin by a rod bearing cap.Connecting rod and rod-bearing caps are assembled during manufacture. Then the hold for the bearing is bored with the cap in place. This is called line-bring. It make each rod and its cap a matched set. Usually, the same number is stamped on the rod and cap. This prevents the caps setting mixed during engine service. If the caps are mixed, the bearing bore will not be round. An engine assembled with the rod bearing caps switched will probably lock the crankshaft. If the crankshaft turns, the bearing will probably have improper clearance and early bearing failure will result.Another reason for keeping the cap and rod matched is to prevent engine unbalance and unwanted vibration. All connecting rods in an engine must be as light as possible. But they must all weigh the same. If one rod is heavier than the other, the engine will vibrate. This could damage the engine.Crankshaft：The crankshaft then main rotating member, or shaft, in the engine. It has crank-pins, to which the connecting rod from the pistons are attached. During the power strokes, the connecting rods force the crank-pins and therefore the crankshaft to rotate. The reciprocating motion of the pistons is changed to rotary motion as the crankshaft spins. This rotary motion is transmitted through the power train to the car wheels.The crankshaft is a strong, one-piece casting, or forging, or heat-treated alloy steel. It must be strong to take the downward force of power strokes without excessive bending. It must be balanced so the engine will run without excessive vibration.Engine DisplacementThe frequently used engine specifications are engine displacement and compression ratio .Displacement and compression ration are related to each other ,as we will learn in the following paragraphs .By Displacement Engine displacement is the amount of air displaced by the piston when it moves fro .The electrical ignition system causes a spark across the spark plug electrodes in the cylinder at the end of the compression stroke ,which ignites the vaporized fuel and air mixture .m compressing the air to ignite the fuel when it is injected into the cylinder at the end of the compression ratios are much higher than gasoline engine compression ratios ,sufficient heat is generated by compressing the air to ignite the fuer of cylinders .engines are classified as low ,medium ,high ,and super high speed .Commonly used to indicate engine size ,this specification is really a measurement of cylinder volume ..The number of cylinders is a factor in determining displacement ,but the arrangement of the cylinders or valves is not .Engine displacement is calculated by multiplying the number of cylinders in the engine by the total engine displacement is the volume displaced by all the pistons .The displacement of one cylinder is the space through which the piston’s top surfa ce moves as it travels from the bottom of its stroke (bottom dead center )to the top of its stroke (top dead center ).It is the volume displaced by the cylinder by one piston stroke .Piston displacement can be calculated as follows :the bore (cylinder Diameter )by gives you the radius of the bore .the radius (multiply it by itself ).the square of the radius by (pi orπ)to find the area of the cylinder cross section .the area of the cylinder cross section by the length of the stroke .You now know the piston displacement for one cylinder .Multiply this by the number of cylinders to determine the total engine displaceme`nt .The formula for the complete procedure reads :R2*π*stroke* cylinders =displacementCompression RatioThis specification compares the total cylinder volume to the volume of only the combustion cylinder volume may seem to be the same as piston displacement ,but it is not .Total cylinder volume .The combustion chamber volume with the piston at top dead center is often called the clearance volume .Compression ratio is the total volume of a cylinder divided by its clearance volume .If the clearance volume is one-eighth of the total cylinder volume ,the compression ratio is 8 (8to1).The formula is as follows :olumeClearancev e Totalvolum =Compression ratio. In theory ,the higher the compression ratio ,the greater the efficiency of the engine ,and the more power an engine will develop from a given quantity of fuel .The reason for this is that combustion takes place faster because the fuel molecules are more tightly packed and the flame of combustion travels more rapidly .But there are practical limits to how high a compression ratio can be .Because of the unavailability of high octane fuel ,most gasolineburning engines are restricted to a compression ratio no greater than to this high ,however ,create high combustion chamber temperatures .This in turn creates oxides of nitrogen (NOx) ,a primary air pollutant .In the early 1970s ,compression ratios were lowered to around 8 to permit the use of lower octane low-lead or unleaded fuel ,and to reduce NOx formation .Advances in electronic engine control in the 1980s have allowed engineers to raise compression ratios to the 9and 10 to 1 range for optimum performance and economy发动机概述发动机是汽车的动力源。

附录A柴油发动机发展和耐久性先进的柴油发动机和后处理技术的发展，2级排放。

Rakesh Aneja 底特律柴油机公司Brian Bolton 底特律柴油机公司Adedejo Bukky Oladipo 底特律柴油机公司Zornitza Pavlova MacKinnon，底特律柴油机公司Amr Radwan 底特律柴油机公司【摘要】先进的柴油发动机和后处理技术已经开发出来并用于多种发动机和汽车平台。

2级（ 2007年及以后）排放标准已说明了轻型载货汽车在FTP-75协议一次测试循环超过了车辆底盘式功率机。

柴油发动机在得到了这些低尾气排放水平的同时又保留了燃油经济性的优势特点。

通过将原型后处理系统与先进的燃烧方式（洁净燃烧）结合，性能和排放取得了不少成果。

洁净燃烧在综合处理之后控制部分种类废气，同时达到氮氧化物和PM降低的目的。

启用引擎的分析工具能够使子系统发展和系统整合。

实验技术的开发方法，利用各种设施，以简化开发的最终解决方案，包括利用稳态和暂态机的测试床，模拟底盘机的测试周期。

【关键词】：柴油发动机， 2级，SCR，后处理，排放，燃烧【引言】在20世纪90年代后期，燃料的使用预测是为未来运输需求而准备的。

展望未来，能源使用其中汽车被证明是相当稳定，前景从2000至2020年，而第三类通过第8类车（重型车辆）被预测在这20年时间里将有微弱的增长。

然而，一个明显的增长主要出现在第1类至第2类车（皮卡，面包车和多功能车）。

在某些情况下，这些都是用在商业上，但是增加的主要部分的来源被认为是客车市场用于个人的运输。

随着这一类汽车使用的增加，能源的使用也会日益增长，从而抬高了能源的使用总量，每天会有数百万桶的原油消费，从20世纪90年代后期的大约800万桶增加至2020年的1200-1300万桶[ 1,2 ]。

如图1所示。

按照预测，到那时汽车的柴油机使用率，其中第一类及第二类轻型卡车的柴油机使用率在美国的交通能源的使用中将有显著的减少。

How Car Engines WorkIntroduction to How Car Engines WorkHave you ever opened the hood of your car and wondered what was going on in there? A car engine can look like a big confusing jumble of metal, tubes and wires to the uninitiated. You might want to know what's going on simply out of curiosity. Or perhaps you are buying a new car, and you hear things like "3.0 liter V-6" and "dual overhead cams" and "tuned port fuel injection." What does all of that mean?If you have ever wondered about this kind of stuff, then read on -- In this article, we'll discuss the basic idea behind an engine and then go into detail about how all the pieces fit together, what can go wrong and how to increase performance.The purpose of a gasoline car engine is to convert gasoline into motion so that your car can move. Currently the easiest way to create motion from gasoline is to burn the gasoline inside an engine. Therefore, a car engine is an internal combustion engine -- combustion takes place internally.Two things to note:There are different kinds of internal combustion engines. Diesel engines are one form and gas turbine engines are another. See also the articles on HEMI engines, rotary engines and two-stroke engines. Each has its own advantages and disadvantages.There is such a thing as an external combustion engine. A steam engine in old-fashioned trains and steam boats is the best example of an external combustion engine. The fuel (coal, wood, oil, whatever) in a steam engine burns outside the engine to create steam, and the steam creates motion inside the engine. Internal combustion is a lot more efficient (takes less fuel per mile) than external combustion, plus an internal combustion engine is a lot smaller than an equivalent external combustion engine. This explains why we don't see any cars from Ford and GM using steam enginesAlmost all cars today use a reciprocating internal combustion engine because this engine is:Relatively efficient (compared to an external combustion engine)Relatively inexpensive (compared to a gas turbine)Relatively easy to refuel (compared to an electric car)These advantages beat any other existing technology for moving a car around.To understand the basic idea behind how a reciprocating internal combustion engine works, it is helpful to have a good mental image of how "internal combustion" works. One good example is an old Revolutionary War cannon. You have probably seen these in movies, where the soldiers load the cannon with gun powder and a cannon ball and light it. That is internal combustion.Almost all cars currently use what is called a four-stroke combustion cycle to convert gasoline into motion. The four-stroke approach is also known as the Otto cycle, in honor of Nikolaus Otto, who invented it in 1867. The four strokes are illustrated bellow ,they are:① Intake stroke ② Compression stroke③ Combustion stroke ④ Exhaust strokeThe piston is connected to the crankshaft by a connecting rod. As the crankshaft revolves, it has the effect of "resetting the cannon." Here's what happens as the engine goes through its cycle：1.The piston starts at the top, the intake valve opens, and the piston moves down to let the engine take in a cylinder-full of air and gasoline. This is the intake stroke. Only the tiniest drop of gasoline needs to be mixed into the air for this to work.2.Then the piston moves back up to compress this fuel/air mixture.Compression makes the explosion more powerful.3.When the piston reaches the top of its stroke, the spark plug emits aspark to ignite the gasoline. The gasoline charge in the cylinder explodes, driving the piston down.4.Once the piston hits the bottom of its stroke, the exhaust valve opensand the exhaust leaves the cylinder to go out the tail pipe.Then the engine gets ready for the next circle .Cylinders, Displacement and Other Engine PartsThe core of the engine is the cylinder, with the piston moving up and down inside the cylinder. The engine described above has one cylinder. That is typical of most lawn mowers, but most cars have more than one cylinder (four, six and eight cylinders are common). In a multi-cylinder engine, the cylinders usually are arranged in one of three ways: inline, V or flat(also known as horizontally opposed or boxer), as shown in the following figures.Different configurations have different advantages and disadvantages in terms of smoothness, manufacturing-cost and shape characteristics. These advantages and disadvantages make them more suitable for certain vehicles.DisplacementThe combustion chamber is the area where compression and combustion take place. As the piston moves up and down, you can see that the size of the combustion chamber changes. It has some maximum volume as well as a minimum volume. The difference between the maximum and minimum is called the displacement and is measured in liters or CCs (Cubic Centimeters, where 1,000 cubic centimeters equals a liter).ValvesThe intake and exhaust valves open at the proper time to let in air and fuel and to let out exhaust. Note that both valves are closed during compression and combustion so that the combustion chamber is sealed.PistonA piston is a cylindrical piece of metal that moves up and down inside the cylinder.Piston ringsPiston rings provide a sliding seal between the outer edge of the piston and the inner edge of the cylinder. The rings serve two purposes:∙They prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump during compression and combustion.∙They keep oil in the sump from leaking into the combustion area, where it would be burned and lost.Most cars that "burn oil" and have to have a quart added every 1,000 miles are burning it because the engine is old and the rings no longer seal things properly.Connecting rodThe connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves and the crankshaft rotates.Crank shaftThe crankshaft turns the piston's up and down motion into circular motion. SumpThe sump surrounds the crankshaft. It contains some amount of oil, which collects in the bottom of the sump (the oil pan).Valve Trains and SystemsThe valve train consists of the valves and a mechanism that opens and closes them. The opening and closing system is called a camshaft. The camshaft has lobes on it that move the valves up and down。

附录1Engine Operating PrinciplesMost 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 strokeWhen 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 strokeThe piston start moving up huge inlet valve closed, and the mixture in the combustion chamber, according to the different factors including compression compression ratio, thethrottle 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 workBurning gas pressure of inflation rose to 3.5 mpa, promote the piston moves to the cylinder, and exhaust door open.4 gas strokeWith 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 V olkswagens.Subaus design is liquid cooled.are often air-cooled,and are found in the Chevrolet Carvair,Porsches,Subaus,and V olkswagens.Subaus design is liquid te-model V olkswagen vans use aliquid-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。

柴油发动机喷射系统外文文献翻译、中英文翻译、外文翻译In the past five years。

there has been a XXX。

with the most significant change being the use of common rail XXX n diesel engines。

which is now receiving increasing n。

While there is also a trend towards direct XXX engines。

this XXX。

such as air n。

XXX.Keywords: fuel supply system。

common rail system。

XXX.The most basic n of any fuel oil supply system is to XXX。

XXX increase in vehicle n requirements。

precise control of the system has XXX。

the fuel oil supply system should not only change the cycle oil but also adjust the XXX.In the mid-90s。

carburetor XXX。

but the control aspect was not accurate。

After many improvements。

the carburetor was able to control each XXX and full XXX。

XXX。

XXX。

and XXX.XXX was common in the early 90s。

timing XXX improvement。

This led to the development of XXX driving。

pushing forward the European XXX.From the fuel system's point of view。

电子类文献中英文翻译发电机Electricity is the backbone of modern society, and it is generated by using various methods, with one of the most common ways being through the use of generators. This article explores the concept of generators and their role in electricity production.GeneratorA generator is a device that transforms mechanical energy into electrical energy. It works on the principle of electromagnetic induction, which was discovered by Michael Faraday in the early 19th century. A generator consists of two parts: the rotor and the stator. The rotor is the rotating part of the generator, while the stator is the stationary part. The two parts are separated by an air gap.When the rotor rotates inside the stator, it produces a magnetic field that cuts across the wires in the stator. This creates an electric current. The amount of electric current generated by the generator depends on the speed of the rotor and the number of wire turns in the stator.Types of GeneratorsThere are two main types of generators: AC generators and DC generators. AC generators generate alternating current, while DC generators generate direct current.AC GeneratorsAC generators are the most common type of generators used in modern society. They produce electrical power by rotating a coil of wire around a magnetic field. This creates a changing magnetic field, which induces a current in the coil. The current flows back and forth at a set frequency, resulting in an alternating current.The advantage of AC generators is that the voltage and frequency can be easily controlled. This makes it possible to build large power plants that can produce electricity at high voltage and transmit it over long distances.DC GeneratorsDC generators are less common than AC generators, but they are still used in some applications. They generate a constant DC voltage by rotating a coil of wire around a magnetic field. The voltage produced by a DC generator is proportional to the speed of the rotor and the number of wire turns in the coil.The main disadvantage of DC generators is that the voltage cannot be easily changed. This makes them unsuitable for large power plants and long-distance transmission.ConclusionGenerators play a vital role in the production of electricity, and the development of more efficient and effective generators has greatly improved the quality of life for people all over the world. The ability to generate electricity has enabled people to access a wide range of electronic devices that improve communication, enable faster transportation, and enhance safety and security. As technology continues to advance, the generators of the future will undoubtedly become even more efficient and effective, providing sustainable, reliable, and affordable energy for generations to come.。

译文标题柴油发动机喷射系统柴油发动机喷射系统 原文标题Diesel engine injection system 作 者Jeff Daniels 译 名 杰夫杰夫 丹尼斯丹尼斯 国 籍 美国美国原文出处 Automotive Design Asia 摘要：柴油喷射压力已提高到2000巴汽油直喷和压电技术都变得越来越常见因为燃油供给系统在不断地改革。

为燃油供给系统在不断地改革。

大约在过去的五年中汽车燃油供给技术发生了一场革命其中变化最大的是柴油发动机在直喷柴油机上运用了共轨系统该系统安装有压电式喷油器现在正受到人们越来越多的关注。

在汽油发动机方面现在也有往直喷技术发展的趋势但这种趋势逐渐趋缓而且并没有都往这个方向发展也有其它新的技术诸如空气引射技术但受材料方面的影响进展也较缓慢。

材料方面的影响进展也较缓慢。

关键词：燃油供给系统燃油供给系统 共轨系统共轨系统共轨系统 压电式喷油器压电式喷油器Abstract: the fuel injection pressure has increased to 2000 bar gasoline direct injection and piezoelectric technology is becoming more common because of fuel supply system in constant reform.About in the past five years automotive fuel oil supply technology was a revolution is one of the biggest changes in diesel engine on the direct injection diesel engine using common rail system is the system equipped with piezoelectric injector is now more and more attention by people. In gasoline engine now has to the trend of the development of the direct injection technology but the trend is gradually slow and not toward this direction also have other new technology such as air ejector technology but also affected by the material aspects of the progress is relatively slow.Keywords:fuel oil supply system Common rail system Piezoelectric injectors1喷射系统发展任何燃油供给系统最基本的功能是向每个汽缸供给足够的燃油通过这种方式任何燃油供给系统最基本的功能是向每个汽缸供给足够的燃油通过这种方式与吸进来的空气混合并燃烧当然燃烧得越完全越好。

汽车发动机外文翻译文献(文档含中英文对照即英文原文和中文翻译)AUTOMOTIVE ENGINE1 Engine Classification and Overall MechanicsThe automobile engines can be classified according to: (1) cycles, (2) cooling system, (3) fuel system, (4) ignition method, (5) valve arrangement, (6) cylinder arrangement, (7) engine speed.Engines used in automobiles are the internal combustion heat engines. The burning of gasoline inside the engine produces high pressure in the engine combustionchamber. This high pressure force piston to move, the movement is carried by connecting rods to the engine crankshaft. The crankshaft is thus made to rotate: the rotary motion is carried through the power train to the car wheels so that they rotate and the car moves.The engine requires four basic systems to run (Fig. 2-1). Diesel engines require three of these systems. They are fuel system, ignition system (except diesel), lubricating system and cooling system. However, three other related systems are also necessary. These are the exhaust system, the emission-control system, and the starting system. Each performs a basic job in making the engine run.Fig. 2-1 The engine construction2 Engine Operating PrinciplesFig. 2-2 Engine termsThe term “stroke” is used to describe the movement of the piston within the cylinder. The movement of the piston from its uppermost position (TDC, top dead center) to its lowest position (BDC, bottom dead center) is called a stroke. The operating cycle may require either two or four strokes to complete. Most automobile engines operate on the four stroke cycle (Fig. 2-2).In four-stroke engine, four strokes of the piston in the cylinder are required tocomplete one full operating cycle. Each stroke is named after the action. It performs intake, compression, power, and exhaust in that order (Fig. 2-3).Intake stroke Compression stroke Power stroke Exhaust strokeFig. 2-3 Four-stroke-cycle gasoline engine1. The intake strokeThe intake stroke begins with the piston near the top of its travel. As the piston begins its descent, the exhaust valve closes fully, the intake valve opens and the volume of the combustion chamber begins to increase, creating a vacuum. As the piston descends, an air/fuel mixture is drawn from the carburetor into the cylinder through the intake manifold. The intake stroke ends with the intake valve close just after the piston has begun its upstroke.2. Compression strokeAs the piston is moved up by the crankshaft from BDC, the intake valve closes. The air/fuel mixture is trapped in the cylinder above the piston. Future piston travel compresses the air/fuel mixture to approximately one-eighth of its original volume (approximately 8:1 compression ratio) when the piston has reached TDC. This completes the compression stroke.3. Power strokeAs the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug. The ignition system delivers a high-voltage surge of electricity to the spark plug to produce the spark. The spark ignites, or sets fire to, the air/fuel mixture. It now begins to burn very rapidly, and the cylinder pressure increases to as much as 3-5MPa or even more. This terrific push against the piston forces it downward, and a powerful impulse is 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.4. Exhaust strokeAt the end of the power stroke the camshaft opens the exhaust valve, and the exhaust stroke begins. Remaining pressure in the cylinder, and upward movement of the piston, force the exhaust gases out of the cylinder. At the end of the exhaust stroke, the exhaust valve closes and the intake valve opens, repeating the entire cycle of events over and over again.3 Engine Block and Cylinder Head3.1 Engine BlockThe engine block is the basic frame of the engine. All other engine parts either fit inside it or fasten to it. It holds the cylinders, water jackets and oil galleries (Fig. 2-4). The engine block also holds the crankshaft, which fastens to the bottom of the block. The camshaft also fits in the block, except on overhead-cam engines. In most cars, this block is made of gray iron, or an alloy (mixture) of gray iron and other metals, such as nickel or chromium. Engine blocks are castings.Fig. 2-4 V6 engine blockSome engine blocks, especially those in smaller cars, are made of cast aluminum. This metal is much lighter than iron. However, iron wears better than aluminum. Therefore, the cylinders in most aluminum engines are lined with iron or steel sleeves. These sleeves are called cylinder sleeves. Some engine blocks are made entirely of aluminum.3.2 Cylinder SleevesCylinder sleeves are used in engine blocks to provide a hard wearing material for pistons and piston rings. The block can be made of one kind of iron that is light and easy to cast while the sleeves uses another that is better able to stand up wear and tear. There are two main types of sleeves: dry and wet (Fig. 2-5).Dry sleeve Wet sleeveFig. 2-5 Cylinder sleeve3.3 Cylinder HeadThe cylinder head fastens to the top of the block, just as a roof fits over a house. The underside forms the combustion chamber with the top of the piston. In-line engine of light vehicles have just one cylinder head for all cylinders; larger in-line engines can have two or more. Just as with engine blocks, cylinder heads can be made of cast iron or aluminum alloy. The cylinder head carries the valves, valve springs and the rockers on the rocker shaft, this part of valve gear being worked by the pushrods. Sometimes the camshaft is fitted directly into the cylinder head and operates on the valves without rockers. This is called an overhead camshaft arrangement.3.4 GasketThe cylinder head is attached to the block with high-tensile steel studs. The joint between the block and the head must be gas-tight so that none of the burning mixture can escape. This is achieved by using cylinder head gasket. Gaskets are also used to seal joins between the other parts, such as between the oil pan, manifolds, or water pump and the blocks.3.5 Oil PanThe oil pan is usually formed of pressed steel. The oil pan and the lower part of cylinder block together are called the crankcase; they enclose, or encase, thecrankshaft. The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and run down into the pan. Thus, there is a constant circulation of oil between the pan and the working parts of the engine.4 Piston Assembly, piston rings , The piston pin ,Connecting Rods, Crankshafts And Flywheel4.1 PistonPiston rings and the piston pin are together called the piston assembly (Fig. 2-6).Fig. 2-6 Piston, piston rings and connecting rodThe piston is an important part of a four-stroke cycle engine. Most pistons are made fr om cast aluminum. The piston, through the connecting rod, transfers to the crankshaft the force created by the burning fuel mixture. This force turns the crankshaft.To withstand the heat of the combustion chamber, the piston must be strong. It also must be light, since it travels at high speeds as it moves up and down inside the cylind er. The piston is hollow. It is thick at the top where it takes the brunt of the heat and th e expansion force. It is thin at the bottom, where there is less heat. The top part of the piston is the head, or crown. The thin part is the skirt. Most pistons have three ring gro oves at the top. The sections between the ring grooves are called ring lands.4.2 piston ringspiston rings fit into ring grooves near the top of the piston. In simplest terms, pisto n rings are thin, circular pieces of metal that fit into grooves in the tops of the pistons. In modern engines, each piston has three rings. (Piston in older engines sometimeshad four rings, or even five.) The inside surface of the ring fits in the groove on the pi ston. The ring's outside surface presses against the cylinder walls. Rings provide the n eeded seal between the piston and the cylinder walls. That is, only the rings contact th e cylinder walls. The top two rings are to keep the gases in the cylinder and are called compression rings. The lower one prevents the oil splashed onto the cylinder bore fro m entering the combustion chamber, and is called an oil ring.4.3 The piston pinThe piston pin holds together the piston and the connecting rod. This pin fits into th e piston pin holes and into a hole in the top end of the connecting rod. The top end of t he rod is much smaller than the end that fits on the crankshaft. This small end fits insi de the bottom of the piston. The piston pin fits through one side of the piston, through the small end of the rod, and then through the other side of the piston. It holds the rod firmly in place in the center of the piston. Pins are made of high-strength steel and hav e a hollow center. Many pins are chrome-plated to help them wear better.A piston pin fits into a round hole in the piston. The piston pin joins the piston to the connecting ro d. The thick part of the piston that holds the piston pin is the pin boss.4.4 Connecting RodsThe connecting rod little end is connected to the piston pin. A bush made from a soft metal, such as bronze, is used for this joint. The lower end of the connecting rod f its the crankshaft journal. This is called the big end. For this big-end bearing, steel-ba cked lead or tin shell bearings are used. These are the same as those used for the main bearings. The split of the big end is sometimes at an angle, so that it is small enough t o be withdrawn through the cylinder bore. The connecting rod is made from forged all oy steel.4.5 CrankshaftsThe crankshaft is regarded as the “backbone” of the engine (Fig. 2-7). The crankshaft, in conjunction with the connecting rod, converts the reciprocating mo tion of the piston to the rotary motion needed to drive the vehicle. It is usually made fr om car-bon steel which is alloyed with a small proportion of nickel. The main bearing journals fit into the cylinder block and the big end journals align with the connecting rods. At the rear end of the crankshaft is attached the flywheel, and at the front end ar e the driving wheels for the timing gears, fan, cooling water and alternator. The throw of the crankshaft, i.e. the distance between the main journal and the big end centers, controls the length of the stroke. The stroke is double the throw, and the strokelength is the distance that the piston travels from TDC to BDC and vice versa.Fig. 2-7 The crankshaft4.6 FlywheelThe flywheel is made from carbon steel. It fits onto the rear of the crankshaft. As well as keeping the engine rotating between power strokes it also carries the clutch, w hich transmits the drive to the gearbox, and has the starter ring gear around its circumf erence. There is only one working stroke in four so a flywheel is needed to drive the c rankshaft during the time that the engine is performing the non-power strokes.5 Valve SystemFig. 2-8 Parts of the valve trainThe valve operating assembly includes the lifters or cam followers, pushrods, rocker arms and shafts or pivot, valve and springs etc. The purpose of this to open and close the intake and exhaust ports that lead to the combustion chambers as required (Fig. 2-8). Valve mechanisms vary depending on the camshaft location. When the camshaft is positioned in the engine block, valve lifters are mounted in the openings above the camshaft. Pushrods are connected from each valve lifter to a pivoted rocker arm mounted above each valve. A lobe on the camshaft is positioned directly below each valve lifter. A typical camshaft drive has a sprocket bolted to the end of the camshaft, and a matching sprocket is attached to the end of the crankshaft. Those two sprockets may be meshed together or surrounded a steel chain to have the camshaft drive. When the lower part of the camshaft lobe is rotating under the valve lifter, the valve spring holds the valve closed.汽车发动机1发动机的分类和整体力学汽车发动机可根据如下因素进行分类：（1）循环系统，（2）冷却系统，（3）燃油系统，（4）点火方式，（5）气门布置，（6）气缸排列，（7）发动机转速。

400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A.Tel: (724) 776-4841 Fax: (724) 776-5760SAE TECHNICAL PAPER SERIES2000-01-1546Lightweight Engine Design StrategiesW. Schöffmann, F. Beste and R. MarquardAVL List GmbH, AustriaReprinted From: 2000 Future Car Congress Proceedings CD-ROM2000 Future Car CongressArlington, VirginiaApril 2-6, 2000The appearance of this ISSN code at the bottom of this page indicates SAE’s consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition,however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc.Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sec-tions 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying for general distribution, for advertising or promotional purposes, for creating new collective works,or for resale.SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Sales and Satisfaction Department.Quantity reprint rates can be obtained from the Customer Sales and Satisfaction Department.T o request permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group.No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.ISSN 0148-7191Copyright © 2000 Society of Automotive Engineers, Inc.Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is published in SAE T ransactions. For permission to publish this paper in full or in part, contact the SAE Publications Group.Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 300word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE.Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in the Global Mobility Database2000-01-1546Lightweight Engine Design StrategiesW. Schöffmann, F. Beste and R. MarquardAVL List GmbH, Austria Copyright © 2000 Society of Automotive Engineers, Inc.ABSTRACTDuring the past years advances in fuel efficiency of car engines did not result in the expected reduction in overall fuel consumption of new car generations. One reason is the increasing vehicle weight. In an overall-weight analysis of an automobile the engine and as part of it, the crankcase represents a single component with a high weight reduction potential. This paper discusses weight reduction strategies using lightweight materials and modern design approaches.The application of lightweight materials for new crankcase concepts implies comprehensive design considerations to achieve weight reductions as close as possible to the potential of the selected material. A specific approach for inline and V-engine crankcase concepts is discussed in detail. Engine weight reduction can also be achieved through substituting large and therefore heavy engines with small high performance engines. Modern technologies applied to existing engine concepts increase the power-weight ratio, the engine’s capability and therefore its marketing value.New lightweight design strategies allow a significant reduction of engine mass compared to conventional concepts and represent an important contribution to reduce the overall vehicle weight.INTRODUCTIONThe demands on the automobile have increased significantly in terms of ecological aspects and are generally set to continue with regard to future transportation concepts. This customer-induced pressure is accompanied by tightened legal requirements especially in the USA and in Europe. In anticipating this fact, answers need to be found to the central question of fuel consumption, emissions and recycling strategies. Progress was made in the development of car engines during the past years. A significant increase in power output in combination with decreased specific fuel consumption and emissions have been obtained through enormous development efforts. The most remarkable advances were achieved through applying direct injection, exhaust-gas turbo charging and multi-valve technology to high performance diesel engines [1. ]. The resulting engine efficiency increases were not translated into vehicle efficiency improvements when a new car model replaced its precursor with a comparable performance. One reason for the stagnating or even decreasing overall vehicle efficiency is an increase of 15-20% in the mass of cars over the past 15 years (Figure 1). Despite the growing use of lightweight materials and the designers’ sensitivity towards lightweight construction, the weight reductions have been more than compensated. Reasons for this include :•additional vehicle features•improved safety and security•improved comfort aspects in regard to NVH •increased power output to maintain or improve car performance•improved reliabilityFigure 1.Vehicle weight increase [Data corresponding to 2. ]This development is not reversible. The continuously growing customer demands and stricter standards support the trend toward heavier cars. Therefore, it is important to identify the most convenient way to reduce the mass of a car engine while maintaining the engine’s performance. Special attention was given to the crankcase, which contributes 20-25% to the overall engine weight. Most challenging is the diesel engine crankcase. Peak firing pressures of up to 16MPa result in the comparably highest specific part loads.Figure 2 shows the weight contribution of the core components of a typical 2 liter gasoline engine. One dominant part is the crankcase yielding a potential for weight reductions of 10-12% based on the cast-iron version.Figure 2.Weight contributions of main engine componentsThe conditions of use for each material need to be improved and the applicability of new, lightweight materials must be evaluated from technical as well aseconomic viewpoints. The purpose of weight reduction is not merely reduced consumption and emissions and improved vehicle performance, it is also suitable to reduce the costs of individual components. This paper discusses the conception of modern high performance engines with regard to the achievable weight reductions.ENGINE CONCEPTEngines with a high power-weight ratio and torque have the highest potential to reduce the engine weight. Direct injection and exhaust gas turbo charging are the key technologies for a maximum power density of modern diesel engines. Four-valve technology should be considered for cylinder diameters of 75mm and above to facilitate an increased power-weight ratio (Pe/m) relative to standard drive units while observing tightened emission laws. Figure 3 displays the growing power-weight ratio for an engine during its production life cycle achieved with only small changes to the base engine structure.The scope for further increases in power-weight ratio and engine torque through technologies such as direct injection and turbo-charging is being narrowed as more stringent emission regulations are enacted. Therefore,structural approaches will win a growing importance to engine development in future. Modern crankcase concepts employing lightweight materials and adapted design concepts are one central contribution to the necessary vehicle weight reductions.Figure 3.Power density progressLIGHTWEIGHT DESIGN CONCEPTS – Different single or combined strategies can be employed to effectively reduce the weight of a typical car engine. Figure 4displays the four main approaches for a lightweight concept. The basic engine concept, the component design and the material are strongly linked due to the accompanying calculations of structural strength and acoustic behavior.Figure 4.Weight reduction strategiesThe dominant boundary conditions for crankcase design result form the production process and functional requirements. Innovative design approaches are essential to utilize the potentials of lightweight materials resulting from their advantage in material density.Because of higher material costs and the in some cases more costly processing simple material substitution from ferrous to lightweight materials yields higher component costs. Only the combined use of lightweight materials and an innovative approach to engine concept and component design results in a lighter and cheaper component (Figure 5).Figure 5. Component optimization and lightweight costsThe effort to find the optimum design for specific lightweight material properties is often limited due to additional requirements imposed by engine familyconcepts. Dedicated production lines, for example, call for constant main dimensions such as bore spacing and top deck height. Nevertheless, increasing the marketing value of an existing crankcase is also feasible through material substitution while keeping the machining and assembly process constant. Redesigning needs to be performed only on the casting itself to adapt it to the changed material properties (Figure 6).Figure 6.Material substitution CI→ Aluminum [3. ]Crankcase design revisions with some flexibility in the machining process and new crankcase designs allow significantly more freedom in the crankcase concept.One example is the make of a crankcase following the AVL trussing concept [4. ]. The main core package comprises a single-piece crank core with two stiff grid cores on each side (Figure 7). The AVL trussing system unites a high weight reduction potential with a stiff structural concept. Other advantages are the acoustic behavior and the design of the oil drain channels with connecting horizontal galleries allowing the integration of the crankcase ventilation.Figure 7.Core package of the AVL trussing conceptAt first this trussing concept was designed as a material optimized concept for compacted graphite iron (CGI)crankcases [5. ] but has also proven to be a base design for gray cast iron (CI) crankcases [6. , 7. and 8. ].A material-sensitive top deck design of a CGI crankcase is shown in Figure 8. In structurally stressed areas the deck thickness is crowned between 10-14mm to obtain good acoustic behavior and to reduce the top deck weight [9. ]. Areas with minor stresses were made with the minimum wall thickness of 3.5mm. A weight-optimized design of crankcase flange areas is of higher significance for the lightweight potential compared to the costly reduction of the minimum wall thickness.Figure 8.T op deck designMATERIAL CONCEPTS – Figure 9 shows a variety of possible crankcase materials and design concepts and their fundamental effect to the component weight.Figure 9.Effect of crankcase material and designCGI offers, despite nearly identical material densities with CI, the superior material strength and a potential weight advantage of about 10% if combined with a consequent lightweight design approach. The shown compound concepts constitute special solutions. A complex skeleton frame made of a ferrous material carries the gas and bolt forces and integrates cylinder liners and threat bosses for the cylinder head and main bearing wall bolts. For the Steel compound (St comp) solution the sealing outer skin is made of cast-in sheet metal [10. ] and the skeleton frame of the Aluminum compound (Al comp) solution is enveloped with an aluminum alloy. The applicability of both concepts for standard low-cost inline crankcases is limited due to the additional costs caused by the complex skeleton frame. An alternative to this technologyfacilitating lightweight materials even for high-speed diesel engines are less complex, separate inlays made of CGI or spherical graphite iron (SGI) in each main bearing wall excluding the cylinder liners.T oday, aluminum, with a weight reduction potential of up to 40%, substitutes the former proven ferrous designs.Especially die-cast crankcases made of secondary aluminum with cast-in CI liners have proven to be a suitable solution for mass production. Decisive reasons beside the dominant weight-reduction potentials are •superior thermal conductivity•potential for advanced manufacturing technologies supporting complex and filigree structures like cast-in oil feeds•high integration potential•tighter range of tolerances possible •marketing advantageMagnesium, the lightest material suitable for crankcases,constitutes a design challenge especially for high-speed diesel engines. Basic risks in the use of magnesium naturally exist, but research programs for mass production magnesium crankcases normally result in beneficial design solutions for the aluminum version.Nevertheless, the current value of the minimum wall thickness for aluminum and magnesium makes it impossible to reduce the weight according to the materials full potential.Selecting the material for a typical crankcase involves defined design parameters as well as the question if the specific properties of the pre-selected material fulfill the requirements of the engine to that component. T able 1summarizes the main material properties. Decisive for the structural stiffness is the ratio of Y oung’s modulus and material density. The tensile strength and Y oung’s modulus mainly influence the static strength of the crankcase and the maximum main bearing and cylinder-head bolt forces. Main parameter for the dynamic strength and the endurable peak firing pressure is the bending endurance limit of the material (fatigue limit).Other important material properties for crankcase designT able parison of main material propertiesCompacted Graphite Iron(GGV 40)Secondary Aluminum(AlSi9Cu3)Magnesium (sand casting alloy)Y oung’s Modulus [kN/mm2]130 - 1607545T ensile Strength [N/mm2]300 - 500200 - 240160 - 180Bending Endurance [N/mm2]160 - 21070 - 9045 - 55Density [kg/dm3]7.1 – 7.42.751.75include thermal conductivity, mechanical and thermal endurance strength, creep resistance at high temperatures, damping coefficient, thermal expansion coefficient, corrosion resistance against cooling fluids,mineral oil and salt water, specific weight and last not least the castability.DESIGN CONCEPTS – The current standard for gasoline inline crankcases is a high-pressure die cast Al crankcase with cast in CI liners and thick main bearing shells of 4.5mm or inlays representing a modern lightweight concept with small potential for further weight reduction. The crankshaft bearings are implemented as a bedplate (Figure 10, left) or as a deep-skirt concept with cut-free main bearing walls and an aluminum ladder frame connecting the skirts (Figure 10, right). One remaining potential of about 0.5kg per cylinder can be found in replacing the CI liners by aluminum liners or by a thermal sprayed coating. Replacing the CI liners also benefits the heat dissipation from the combustion chambers by avoiding microscopic gaps between the CI liners and the surrounding material. Substituting the crankcase material with magnesium reduces the weight further.Figure 10.In-line gasoline crankcase conceptsThe common material for diesel inline crankcases with peak firing pressures of up to 16MPa is CI. Modern crankcases correspond to the deep-skirt concept mentioned above with SGI bearing caps and an aluminum ladder frame (Figure 11, left).This crankcase design concept is based on the tunnel-concept of the technological demonstration engine AVL LEADER [11. and 12. ]. The purpose of this concept is the acoustic decoupling of the main bearing walls excited by high combustion gas forces and the sound radiating outer crankcase structure. This design results in a relative flexible main bearing wall while the “tunnel”constitutes a structure with a high torsional and bending stiffness. A one-piece tunnel crankcase as cast for the first prototype of the AVL-LEADER engine is unacceptable for modern high volume production.Therefore, the shown production optimized crankcase requires a two-piece design [13. ], oil-pump and suction pipe can be integrated in the ladder frame.Figure 11.In-line diesel crankcase conceptsThe use of aluminum alloys for diesel and aluminum inline crankcases within one engine family offers the chance of a combined production. T oday aluminum is the standard material for gasoline crankcases. But the broad use for high-speed diesel engines is still prevented by questions regarding the achievable strength of the main bearing wall, the warping of cylinder liners and top deck and the al behavior.High potential to reduce the crankcase weight while ensuring the high structural stiffness has the compound concept. Investigations are currently conducted for a sand-cast aluminum/magnesium compound crankcase.The crankcase shown in Figure 11, right is designed as a bolt-through concept and optionally includes inlays in bedplate and/or crankcase to support the main bearing shells. Thread bosses integrated in these inlays are also capable to replace the bolt-through joint to avoid costly assembly procedures.Latest production gasoline V-engine crankcases are built, as are the their inline versions, of a high-pressure die cast aluminum crankcase and bedplate with only a small potential for further weight reductions by replacing the CI liners. Currently most diesel V-engine crankcases are made of CI, due to their high peak firing pressures. Bedplate designs with the separation plane through the crankshaft centerline and deep-skirt designs with SGI bearing caps have proven to be suitable concepts. Four bolts per main bearing and in case of single bearing caps additional horizontal bolts are essential to relieve the load on the cross guides of the bearing caps. Because of its superior material properties CGI is increasingly taken into consideration for diesel V-engine crankcases. A significant weight reduction relative to CI is possible especially in the high loaded areas around the main bearings. Different design solutions for diesel V-engine crankcases were compared using the finite element analysis.The chosen sand cast crankcase for this investigation is designed for a 90° V8-Engine (Figure 12, left). The finite element analysis considers four bolts per main bearing wall and a thick bearing shell of 4mm to reduce thermal expansion of the main bearings.Figure 12.V-engine crankcase designsFINITE ELEMENT ANALYSISExtensive finite element analyses were conducted for thehalf-cylinder 3D models of the inline and V-engine crankcases. The finite analysis model consists of thecrankcase and bedplate sections, the half of the bearing shells and of the cylinder head and main bearing bolts (Figure 13). Special attention was given to the critical area around the main bearing wall to calculate the endurable peak firing pressures.The finite element models of the different variants were loaded with static main bearing bolt forces calculated for different peak firing pressures and with dynamic loads taking different engine temperatures into account. The peak firing pressure limits listed below resulted from the calculated safety factors and the main bearing deformations under static and dynamic load. The different variants analyzed in this investigation were necessary to take different lightweight materials –secondary aluminum (AlSi9Cu3), warm hardening aluminum (AlSi10Mg wa), a sand cast magnesium alloy –and compound versions with SGI and CGI inlays into consideration. Figure 14 summarizes the results.Previous calculations resulted in a limit of 13.5MPa for the in-line high-pressure die-cast crankcases of a production diesel and gasoline engine family. This bedplate design was analyzed with reinforcing inlays.Figure 14.Peak firing pressure limits (cylinder spacing/bore = 1.12)The investigations of the inline crankcase (shown in Figure 11, right) yielded a peak firing pressure limit of 11.5MPa when using the sand-cast magnesium alloy without reinforcement. The secondary aluminum (AlSi9Cu3) reached its limit at 13.0MPa and peak firing pressures of up to 14.5MPa require the warm hardening aluminum alloy (AlSi10Mg wa) if no inlays are used. CGI or SGI inlays embedded in the aluminum or magnesium alloy base structure will allow peak firing pressures of 15MPa or more to be achieved.The design of V-engine crankcases for aluminum and magnesium alloys is, because of V-engine design features, more demanding than for inline crankcases.Each main bearing wall has to withstand the load of two cylinders instead of one, the necessary offset of the two cylinder banks weakens the wall structure and bolt through solutions with a straight force transmission (cylinder head – main bearing cap) are not possible.These constraints reduce the expectable peak firing pressure limits compared to their inline counterpart.Figure 13. Finite element modelsDue to their principal use in upper class vehicles, V-engines normally allow slightly higher costs for their components. The cast-in CGI or SGI skeleton frame is suitable to increase the peak firing pressure limit to 14MPa and above (Figure 12, right). The offset of cylinder-head bolts and main bearing wall strongly encourages the use of a complex frame instead of separate inlays for each main bearing wall. An additional reduction in the crankcase weight of about 0.5kg/cylinder is feasible if sprayed multi-component liners, aluminum liners or a thermal coating are used instead of the skeleton frame integrated liners.SUMMARY/CONCLUSIONSThe potential of ferrous crankcases even with thin-wall technologies is limited in comparison with lightweight materials because of the achievable minimum wall thickness. Aluminum alloys offer, in addition to their low material density, the possibility of a combined production of gasoline and diesel engines versions within one engine family. The critical aspects of the use of lightweight materials for modern crankcases are the achievable strength of the main bearing wall especially for high-speed diesel engines, the warping of cylinder liners and top deck and the acoustic behavior of lightweight crankcases.The application of lightweight materials for V-engine crankcases is restricted in terms of the achievable strength. If no reinforcing measures are implemented, the finite element analysis results suggest peak firing pressure limits of 14.5MPa for in-line and of 14.0Mpa for V-engine crankcases. Additional reinforcing inlays (of SGI or CGI) in the main bearing wall are essential to withstand the high peak firing pressures (15.0MPa and more) of modern high-speed diesel engines. Complex cast-in skeleton frames are suitable only for V-engine crankcases where the primary use in upper class vehicles allows slightly higher component costs. The skeleton frame is best able to compensate for the cylinder bank offset and to carry the load of two cylinders per main bearing wall. Optionally the cylinder liners can be an integrated part of the skeleton frame.The lightest material suitable for crankcases, magnesium, constitutes a design challenge especially for high-speed diesel engines. Research programs continue to work on design solutions for magnesium crankcases to exploit its potential.The development of lightweight crankcases is not a merely a question of the selected material, but of the overall concept and design of an engine. The lightweight concepts presented in this paper are increasingly being introduced to volume production and underline the strategy to commit to lightweight design of crankcases especially for modern high-speed diesel engines.REFERENCES1.R. Glanz, P. 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