汽車英語Engine(2.1-2.4).ppt

,Review 1: Engine Terms,TDC（top dead center）: the position of the crank and piston when the piston is farther away from the crankshaft.,BDC（bottom dead center）: the position of the crank and piston when the piston is nearest away from the crankshaft.,2.1: principle of operation,Stroke: the distance between BDC and TDC; stroke is controlled by the crankshaft. Four-stroke Two-stroke,swept volume: the volume between TDC and BDC.,Bore: the internal diameter of the cylinder.,engine capacity,compression ratio,Clearance volume: the volume of space above the piston when it is at TDC.,Engine capacity: this is the swept volume of all cylinders.,Compression ratio: (swept vol+clearance vol) / (clearance vol),The spark-ignition engine is an internal combustion engine with externally supplied in ignition, which converts the energy contained in the fuel to kinetic energy. The cycle of operations is spread over four piston strokes. To complete the full cycle it takes two revolutions of the crankshaft. 火花點(diǎn)火式發(fā)動機(jī)是一個外部提供點(diǎn)火的內(nèi)燃發(fā)動機(jī)，它把燃料中的能量轉(zhuǎn)化成動能 工作循環(huán)分布在活塞的四個行程，完成整個行程曲軸需要轉(zhuǎn)兩周,Intake(induction) stroke,Review 2: List the four strokes of a four-stroke engine .,Compression stroke,Power stroke,Exhaust stroke,Crankshaft and connecting rods system,Review 3: List the main systems of a gasoline engine .,Valve system,Fuel system,Ignition system,Lubrication system,Cooling system,Starting system,Energy and power: Engines used in automobiles are internal combustion heat engines. They convert the chemical energy of the gasoline into heat within a power chamber that is called a combustion chamber. Heat energy released in the combustion chamber raises the temperature of the combustion gases within the chamber. The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power.,Engine terms: Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn. The power stroke “uses up“ the gas, so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture: this control of gas movement is the duty of the valves;,活塞通過連桿和曲軸連接，使得氣體帶動曲軸旋轉(zhuǎn)半圈。作功沖程耗盡了所有的氣體，這樣就必須采取相應(yīng)的措施排出廢氣以及向氣缸內(nèi)充入新鮮的可燃混合氣：氣體的運(yùn)動由氣門來控制。,2.2： engine block and cylinder head Basic words（）,曲軸箱,汽缸蓋罩,汽缸,汽缸套,汽缸體,油底殼,汽缸蓋,襯墊,水套,油道,Engine block: The 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. The engine block also holds the crankshaft, which fastens to the bottom of the block. The camshaft also fits inside the block, except on overhead-cam-engines (OHC). 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.,氣缸體是發(fā)動機(jī)的基體。發(fā)動機(jī)其它的部件都安裝在缸體內(nèi)或固定在缸體上，它包含了氣缸、水套和油道，以及固定在缸體底部的曲軸等。除凸輪軸頂置發(fā)動機(jī)外，凸輪軸也裝在汽缸體中大多數(shù)汽車汽缸體由灰鑄鐵或灰鑄鐵與其它金屬如鎳、鉻的合金制造而成。,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. 汽缸體由質(zhì)量較輕且易于鑄造的一種鑄鐵制成，而缸套則用另一種抗磨和抗拉缸能力較好的鑄鐵,The dry sleeve can be cast in or pressed into a new block or used to recondition badly worn or damaged cylinders that cannot easily be rebored.,干缸套可以鑄在或壓入新缸體中，或者用于嚴(yán)重磨損或損壞而又不易重鏜的缸體的修復(fù)。,wet sleeve,dry sleeve,Cylinder sleeve:,Cylinder head: The 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 engines of light vehicles have just one cylinder head for all cylinders; larger in-line engines can have two or more.,氣缸蓋扣在缸體的頂部，就像屋頂安在房子上一樣。缸蓋的下方和活塞頂部形成燃燒室。輕型車的直列發(fā)動機(jī)所有缸僅有一個氣缸蓋，較大的直列發(fā)動機(jī)有兩個或更多缸蓋。,hemi,Semi-hemi,wedge,桑塔納 夏利 富康,切諾基,捷達(dá) 奧迪,Cylinder head: The cylinder head carries the valves, valve springs and the rockers on the rocker shaft, this part of the valve gear being worked by push-rods.,缸蓋上裝有氣門、氣門彈簧和搖臂軸上的搖臂，推桿推動這部分氣門傳動機(jī)構(gòu)工作。,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 runs down into the pan. Thus,there is constant circulation of oil between the pan and the working parts of the engine.,潤滑系的機(jī)油泵從油底殼抽出機(jī)油，并把機(jī)油輸送給發(fā)動機(jī)的所有工作部件。機(jī)油從油底殼流進(jìn)流出。因而機(jī)油在油底殼和發(fā)動機(jī)的工作部件之間不斷循環(huán)流動。,Oil pan:,2.3 piston, connecting rod and crankshaft,活塞環(huán),活塞（頭部裙部）,活塞銷,連桿,飛輪,曲軸,曲柄軸徑,Basic words:,Piston assembly: Most pistons are made from 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.,大多數(shù)活塞由鋁鑄造而成。通過連桿，活塞把可燃混合氣燃燒所產(chǎn)生的力傳遞給曲軸，并帶動曲軸旋轉(zhuǎn)。,Piston :,In disel engines, the combustion chamber may be formed totally or in part in the piston crown, depending on method of injection.,柴油機(jī)發(fā)動機(jī)根據(jù)噴油方法不同，活塞頭部可以形成全部燃燒室，也可以是燃燒室的一部分,Piston rings: In modern engines, each piston has three rings. (Piston in older engines sometimes had four rings, or even five.) The inside surface of the ring fits in the groove on the piston. The rings outside surface presses against the cylinder walls.,在新型發(fā)動機(jī)上，每個活塞有三個活塞環(huán)。（在老式發(fā)動機(jī)上，每個活塞有四個甚至五個活塞環(huán)。）環(huán)的內(nèi)邊面緊貼在活塞的環(huán)槽里，環(huán)的外表面緊壓在氣缸壁上。,Connecting rod: The 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 fit the crankshaft journal. This is called the big end.,連桿小頭與活塞銷連接，用在連接處的襯套是由諸如青銅這種較軟材料所制成的。連桿下端連接在曲軸的軸徑處，稱為連桿大頭。,Small enough to be withdrawn through the cylinder bore.,Cylinder nu