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Unit 2-1 Main Components of Engine,1,Contents,Ⅰ．Pre-questions,II. Text Explanation,III. Exercises,2,Pre-questions,,,,The heart of automobile,3,Pre-questions,What impression of the engine?,complicated,power,4,Pre-questions,What are there types of the engine? electric motors, steam engines, and internal combustion engines What’s the internal combustion engine? burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle.,5,,,Single-cylinder engine,cylinder,piston,Piston pin,Connecting rod,crankshaft,Oil pipe,Intake valve,Exhaust valve,Timing gear,Oil pump,6,Pre-questions,what is the power source of automobile and how to produce?,piston,piston pin,connecting rod,crankshaft,Engine Power is produced by the linear motion of a piston in a cylinder. The connecting rod transmits the up-and-down motion of the piston to the crankshaft, which changes it into rotary motion.,7,Pre-questions,The engine comprises two mechanism and five systems, what are they ? crankshaft and connecting rod mechanism, valve gear, cooling system, lubricating system, fuel system, starting system, ignition system,8,,,connecting rod,flywheel,crankshaft,piston,intake valve,exhaust valve,push rod,tappet,timing gears,■ Valve gear ■ Connecting rod,9,,,Engine cooling system,,10,,,Engine lubricating system,,11,,,Fuel supply system,12,,,Valve gear,13,Pre-questions,What’s the function of the crankshaft and connecting rod mechanism? Its function is to convert heat energy into mechanical energy used to drive the vehicles.,14,II. Text Explanation,The internal combustion engine, as its name indicates, burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle. 譯文：內(nèi)燃機(jī)，顧名思義，就是燃料在氣缸內(nèi)部燃燒，并且把燃燒時的膨脹力轉(zhuǎn)化為驅(qū)動車輛的旋轉(zhuǎn)力。,15,II. Text Explanation,Of all automobile components, an automobile engine is the most complicated assembly with dominant effects on the function of an automobile. complicated [?k?mplikeitid] adj.復(fù)雜的, 難解的 dominance [?d?m?n?ns] n.優(yōu)勢, 統(tǒng)治 譯文：汽車發(fā)動機(jī)是一切汽車部件中結(jié)構(gòu)最復(fù)雜，對汽車功能起支配作用的一個總成。,16,II. Text Explanation,Its function is to convert heat energy into mechanical energy used to drive the vehicles. Convert……into… 轉(zhuǎn)變；變換 譯文：它的作用就是將熱能轉(zhuǎn)換成機(jī)械能用來驅(qū)動汽車 。,17,II. Text Explanation,Convert…into…. ①轉(zhuǎn)變；變換 That building has been converted into a school. 那座樓房改成學(xué)校了。 ②兌換 I want to convert some Hong Kong dollars into American dollars. 我想把一些港元換成美元。 ③改變信仰、黨派或意見等 She managed to convert him to her opinion. 她終于設(shè)法說服了他接受她的意見。,18,II. Text Explanation,Power is produced by the linear motion of a piston in a cylinder. linear [? lini?] adj. 線的, 直線的, 線 性的 piston [? pist?n] n.活塞,19,II. Text Explanation,The piston attached to the top of a connecting rod by a pin, called a piston pin or wrist pin. attach to v. 連接 connecting rod 連桿 piston pin = wrist pin 活塞銷,20,II. Text Explanation,The connecting rod transmits the up-and-down motion of the piston to the crankshaft, which changes it into rotary motion. transmit…to … 把…傳到… which changes it into rotary motion 定語從句,21,III. Exercises,diesel engines water pump the ignition distributor oil pan timing gear crankshaft and connecting rod mechanism valve gear fuel system exhaust pipe exhaust manifold,Translate the following expressions into Chinese.,柴油發(fā)動機(jī) 水泵 分電器 油底殼 正時齒輪 曲柄連桿機(jī)構(gòu) 配氣機(jī)構(gòu) 燃油系統(tǒng) 排氣管 排氣歧管,22,III. Exercises,1-cylinder head cover 2-piston 3-timing toothed belt 4-water pump 5-oil pan 6-oil pump 7-crankshaft 8-flywheel 9-distributor 10-valve,23,III. Exercises,The crankshaft represents the final link in the conversion of reciprocating motion at the piston to one of rotation at the flywheel. In the cast of the multi-cylinder engine, the crankshaft has to control the relative motions of the pistons, while receiving their own impulses. A one-piece construction is most commonly used for the motor-vehicle crankshaft, which extends the whole length of the engine and must therefore possess considerable rigidity .,24,III. Exercises,The timing-drive for the engine valve mechanism is taken from the front end of the crankshaft as is the pulley and belt drive for the engine auxiliaries, such as the cooling fan and the alternator for electrical system. attached to the rear end of the crankshaft is the engine flywheel .,25,III. Exercises,I. Translate the following sentences into Chinese. 1．Engine is the power source of the automobile. Power is produced by the linear motion of a piston in a cylinder. 發(fā)動機(jī)是汽車的動力源.它通過汽缸內(nèi)的活塞線性運(yùn)動產(chǎn)生的. 2．The fuel system works according to the requirements of the engine as it provides an air-fuel mixture which must be in proportion to the speed and load placed on the engine. 燃油系統(tǒng)的作用是根據(jù)發(fā)動機(jī)的轉(zhuǎn)速和負(fù)荷提供一定比例的可燃混合氣以滿足發(fā)動機(jī)的需求。,26,III. Exercises,3．The valve gear provides timely admission of the fresh charge into the cylinders and exhaust of spent gases from them. 配氣機(jī)構(gòu)機(jī)構(gòu)可定時的將新鮮氣體充入氣缸，并且將廢氣排放出去。,27,III. Exercises,1．發(fā)動機(jī)主要有兩大機(jī)構(gòu)五大系統(tǒng)組成。 An engine is mainly composed of two mechanisms and five systems. 2．曲柄連桿機(jī)構(gòu)主要包括機(jī)體組，活塞連桿組和曲軸飛輪組。 The crankshaft and connecting rod mechanism mainly consists of the engine crankcase and cylinder block, the piston and connecting rod, the crankshaft and flywheel.,II. Translate the following sentences into English.,28,III. Exercises,3．水泵工作時，可以將冷卻液在發(fā)動機(jī)水套中和散熱器之間來回流動。 When revolving, the water pump circulates coolant between the engine water jackets and the radiator.,29,III. Exercises,Principle of Four-stroke Engine,,1、intake stroke 2、compress stroke 3、power stroke 4、exhaust stroke,Intake valve,Exhaust valve,30,Thank You !,31,