第二章机体组及曲辆连杆机构 《Automotive Configuration,》 口h年2 Engine hlack.Cr4 nd Consecting民ad3 lechaaism 11n Lattaner De山山wawh 色工保 Te中a的传 种组 @R冷大？ 窗凡冷法司 窗凡冷木写 2.2 Crank and Connecting Rod Mechanism 2.21 Gan farcaa 22 (德两链并原意) H @凡冷大司 23 Engine Block机体想) The prmary banitim that the enpae badk Baillk ane ad金adem Aad可山hk 息。1验鱼了线 SthL titanlan a4lu用 点31o色4gTI1国sw 最2场鱼盖每好 包R冷法？ 物P冷 应凡冷大 Page 1Page 1 1 同济大学汽车学院 《Automotive Configuration》 Lecturer ： Dr. Li Liguang/Professor Department：School of Automotive Studies, Tongji University Contact： liguang@tongji.edu.cn Lecture Schedule：12-13 2nd Semester Week 1~8 2 同济大学汽车学院 第二章 机体组及曲柄连杆机构 Chapter 2 Engine Block, Crank and Connecting Rod Mechanism 2.1 Overview 概述 2.2 Crank and Connecting Rod Mechanism 曲柄连杆机构工作原理 2.3 Engine Block 机体组 2.4 Cylinder Head 气缸盖 2.5 Piston-Rod Assemblies 活塞连杆组 2.6 Shaft-Flywheel Assemblies 曲轴飞轮组 3 同济大学汽车学院 Function: The power system for reciprocating internal combustion engines uses a crank drive in which the connector rod end or the connecting rod joins the piston with the crankshaft (曲轴). The conrod converts the reciprocating (往复式 ) movement of the piston into rotary motion. Moreover, the conrod transfers forces from the piston to the crankshaft. 2.1 Overview Working Condition: Directly exposed to gas with high temperature and pressure inside the cylinder The inertia (惯性力) of the moving masses is relatively big due to high engine speed Corrosion (腐蚀) problem brought by high temperature exhaust gas Lack of lubrication (润滑). Component: Engine block (机体组) Piston-rod (活塞连杆组) Shaft-flywheel (曲柄飞轮组) 4 同济大学汽车学院 Working Condition: High Temperature (up to 2500K) High Pressure (5~9MPa) High Speed (3000~6000r/min )(100~200 stroke/s) Chemical Corrosion (Cylinder, Cylinder head, Piston Components) Loading: Load under high pressure and variable motion, consist of gas force, inertia force, friction (摩擦), and other resistances 2.2 Crank and Connecting Rod Mechanism （曲柄连杆组原理） 5 同济大学汽车学院 2.2.1 Gas forces Working Stroke(做功冲程) Fp PistonFp1、Fp2 Fp1conrodFR、FS。 FS Torque on crankrotation Fp2Lateral Pressure (侧压力) Supported by engine block Compression Stroke（压缩冲程） F’p F’p1、F’p2 F’p1 R’，S’ R’ Packing Force； S’ anti-torque T’， F’p2 Lateral Pressure 6 同济大学汽车学院 2.2.2 Inertia(惯性力) and centrifugal（离心力） Force Inertia force: Generated during the linear reciprocating motion of piston(活塞), and Small-end eye(连杆小头) Changing law of piston velocity(from TDC to BDC): 0~accelerate~maximun~deccelerate~0 Piston moving downwards: Accelerate the first half stroke, direction of inertia force points up Decelerate the second half stroke, direction of inertia force points down Centrifugal force: Generated during rotation of crank(曲柄), and big-end eye(连杆大头) Determined by crank radius, rotation mass, and engine speed Larger mass of piston and connecting rod leads to bigger inertia force and centrifugal force, which would increase the vibration of engine and periodic load on components and bearing, which cause abrasion (磨损)and deformation( 变形). 7 同济大学汽车学院 Application Mass Material Mass production truck diesel 1.6 to 5 kg Forged Steel(锻钢) Mass production passenger car gasoline engine 0.4 to 1 kg Forged Steel, gray casting（灰铸铁）， sintered steel（烧结钢） Sport use 0.4 to 0.7 kg Steel, titanium Racing engine/F1 0.3 to 0.4 kg Titanium, carbon fiber Compressor 0.2 to 0.6 kg Aluminum 2.2.2 Inertia(惯性力) and centrifugal（离心力） Force Conrod Masses for Various Applications 8 同济大学汽车学院 The primary functions that the engine block fulfills are: • Absorbing the gas and mass forces in the crankshaft bearings (衬套) and at the cylinder head bolts. • Accepting the energy conversion assembly, comprising the pistons, conrods, crankshaft, and flywheel. • Carrying the crankshaft and (only rarely today) the camshaft(凸轮轴) • Accepting channels to convey operating media, primarily lubricants and coolant. Because of the variety of functions to be carried out, the engine block is subjected to differing types of loads that are superimposed one upon another. The engine block is the component that encloses the cylinders, the crankshaft, the cylinder head, and the head gasket (气缸垫). 2.3 Engine Block（机体组） 9 同济大学汽车学院 曲轴箱 Crankcase 气缸体 Engine block 气缸垫 气缸盖 Head gasket Cylinder head 气缸 Cylinder 油道和水道 Oil and coolant channels 油底壳 Oil pan 气缸盖罩 Cylinder head cover