Unit 2 Piston Crank Mechanism and Valve Mechanism

Part A Piston Crank Mechanism

Part B Valve Mechanism

Part C VTEC - Variable valve Timing and lift Electronic Control

Part D Dialogue

New words

Phrases and Expressions

Piston Crank Mechanism

Piston crank mechanism consists of three parts: engin

e block group; piston and connecting rod group; crankshaft

and flywheel group. Engine block group include cylinder blo

ck, crankcase, cylinder head, cylinder gasket and oil pan. P

iston and connecting rod group is composed of piston, pist

on ring, piston pin, connecting rod and connecting rod beari

ng. Crankshaft and flywheel group comprises crankshaft, cr

ankshaft bearing and flywheel.

Cylinder Block

Cylinder Head

Pistons

Piston Pins

Piston Rings

Connecting Rods

Crankshaft

Piston Crank Mechanism

Flywheel

Valve mechanism vary depending on the camshaft location. When the camshaft is positioned in the engine block, valve lifters are mounted in openings above the camshaft. Push rods 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. These 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.

Valve Mechanism

Valve Mechanism

Valves

Camshaft

Lifters

Push Rods and Rocker Arms

Timing Gears

VTEC (standing for Variable valve Timing and li

ft Electronic Control) is a system developed by Hond

a Motor Co., Ltd. to improve the combustion efficienc

y of its internal combustion engines throughout the R

PM range. (12)This was the first system of its kind an

d eventually lead to different types of variable valve ti

ming and lift control systems that were later designed

by other manufacturers (ie. VVT-i from Toyota or VA

NOS from BMW).

VTEC - Variable valve Timing and lift Electronic Control

Introduction to VTEC

DOHC VTEC

SOHC VTEC

i-VTEC

VTEC - Variable valve Timing and lift Electronic Control

A: Let’s discuss the terms of payment. B: Is it OK I pay by banker’s Transferred? A: Sorry, I’m afraid not . We accept payments in cash or

by credit cards only. B: But I don’t think I have enough cash with me and I

have no credit card.A: We have installment payment that can help you. The

first installment should be paid a week before the shipment. The second one would be paid 1 day before the shipment. Then pay the last installment when you get the car.

B: How much is the down payment.A: It’s 1/3 of the priceless.B: That’s great. I’ll pay the down payment now.A: I’m glad our business is going quite smoothly.

Dialogue

crankcase[kræŋkkeis] n. 曲轴箱catheter[kæθitə] n. 导尿管 , 尿液管 , 导管portal[pɔ:təl] n. 入口injector[indʒektə] n. 喷油器process[prəuses] n. 过程 , 工序 vt. 加工 ; 处理aluminum [ælju:minjəm] n. 铝alloy [ælɔi] n. 合金groove [ɡru:v] n. 沟 , 槽ridge [ridʒ] n. 脊 , 山脊offset [ɔfset] vt. 抵消 , 补偿seizure [si:ʒə] n. 捉住 , 查封 , 扣押polish [pɔliʃ] vt. & vi. ( 使 ) 光滑 , 擦亮 n. 光泽剂 , 亮漆precise [prisais] adj. 精确的 , 准确的bushing [buʃiŋ] n. 轴衬 , 套管scrape [skreip] vt. & vi. 刮 , 擦气

New words

forge [fɔ:dʒ] vt. 锻造 , 伪造 n. 锻造车间 ; 铁匠铺journal [dʒə:nl] n. 轴颈clamp [klæmp] vt. & vi. 夹紧 ; 夹住 n. 夹具thrust [θrʌst] vt. & vi. 猛推 , 刺 , 戳distortion [distɔ:ʃən] n. 曲解 , 失真 , 歪曲undue[ʌndju:] adj. 不当的 ; 过分的 ; 过度的counterweight [kauntəweit] n. 平衡物 , 称锤 , 平衡力sprocket [sprɔkit] n. 链轮齿overlap [əuvəlæp] vt. & vi. 部分重叠 n. 重叠的部分inertia [inə:ʃjə] n. 不活动 , 惰性 , 〈物〉惯性pivot [pivət] n. 枢 , 枢轴 vi. ( 似 ) 在枢轴上转动 vt. 把…放在枢轴上valve [vælv] n. 阀 , 活门cam [kæm] n. 凸轮eccentric [iksentrik] adj. 古怪的 , 怪癖的 ; 异乎寻常的hydraulic [haidrɔ:lik] adj. 液力的 , 液压的

New words

Phrases and Expressionsengine block group 机体组piston and connecting rod group 活塞连杆组crankshaft and flywheel group 曲轴飞轮组cylinder block 气缸体cylinder head 气缸盖cylinder gasket 气缸垫oil pan 油底壳piston ring 活塞环piston pin 活塞销spark plugs 火花塞Piston clearance 活塞间隙compression rings 气环oil rings 油环fan belt pulley 风扇皮带轮water pump 水泵

Phrases and Expressionsvalve lifter 气门挺杆rocker arm 气门摇臂valve seat 气门座valve guide 气门导管valve spring 气门弹簧push rod 气门推杆timing gear 正时齿轮cam lobe 凸轮凸角air/fuel mixture 可燃混和气VTEC （ Variable valve Timing and lift Electronic Control ）可变气门正时和升程电子控制系统VVT-i( Variable Valve Timing-intake) 控制进气凸轮轴气门正时的装置VANOS (Variable Nockenwellen Steuerung) 无级可变气门定时系统

Thank You !