Automotive Configuration) 篇八章发动机剂滑系 8.1 Fumction aad components of lubrication system (0T镜雨T项) .Function Lattaner De山山wawh Te中a的传 @R冷大？ 降害大弹究卓单智 窗R冷大司 四 窗凡冷大复 8.1.2 Cemponents of System 81.2 Componeat of L.ubrication System G钩滑属的镇速) 胸接系的世成 探滑内式 Feoeed-feedaghaen() 四 8.2 Lubricants 8.2.1 Lohricaats Characteristies and Aditinives (调W雨) (明操物性是明滑爆加荆》 ▣巴☒-▣巴 包R冷法？ 物日海大至 四 窗R冷大 Page 1
Page 1 1/23 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 2/23 同济大学汽车学院 第八章 发动机润滑系 Chapter 8 Lubrication System for Automotive Engines 8.1 Function and components of lubrication system 润滑系统的功用与组成 8.2 Lubricants 润滑剂 8.3 Oil pumps 机油泵 8.4 Oil filters 机油滤清器 8.5 Heat transmitters (Oil cooler) 机油冷却器 3/23 同济大学汽车学院 • Function Reduction of friction and wear (润滑作用) Precision sealing (密封作用) Cooling (冷却作用) Cleaning (清洗作用) Corrosion (防锈蚀作用) Power transmission (传动作用) Reduction of noise (降噪作用) Damping impact and vibration ( 减震缓冲作用) 8.1 Function and components of lubrication system （润滑系统功用及组成） Video 4/23 同济大学汽车学院 • Forced-feed lubrication (Pressure Lubrication) Video Oil is pumped to friction surfaces at certain pressure Used in crank bearings, cam bearings, etc • Splash lubrication (飞溅润滑) Video Oil is splashed to friction surfaces by movement of engine components Used for friction surfaces that exposed to air, such as piston pin, cam face, and tappet • Periodic lubrication Greases is used instead of oil to do periodic lubrication for engine components with light loads Mainly used in bearings for water pump and generator 8.1.1 Lubrication Methods （润滑方式） 5/23 同济大学汽车学院 8.1.2 Components of Lubrication System （润滑系的组成） 6/23 同济大学汽车学院 8.1.2 Component of Lubrication System (润滑系的组成) 7/23 同济大学汽车学院 Oil Intake screen Oil pump Filter Main channel Connecting rod bearing Crankshaft main bearing Camshaft bearing Oil pump, distributor bearing rockshaft Oil pan Air compressor Fine filter Timing gear 8/23 同济大学汽车学院 • Types of lubricants Lubrication oils Greases（润滑脂） 8.2 Lubricants （润滑剂） Engine oils (机油) Universal oils for tractors (通用拖拉机油) Two-stroke oils for motorcycles (二冲程摩托车用机油) Transmission oils (传动润滑油) • Task of lubricants Wear protection (润滑) Cooling (冷却) Protection from deposits (清洗积碳) Sealing (密封) Corrosion protection (防锈) 9/23 同济大学汽车学院 • Working condition Exposed to high temperature air and metal walls, easily get oxidized Severely polluted by fuel vapor, exhaust gas, wear particles and deposits Wide range of working temperature (ambient temperature to over 300℃) • Lubrication Requirements Viscosity Temperature Behavior: thin when cold, viscous when hot (适当的粘度) Aging stability: resist of oxidation (氧化安定性) Anti-corrosion property: oxidation of oil generates acid (防腐蚀性) Low foamability (低起泡性) Detergency and dispersibility: ability to remove wear particles and deposits (清净分散性) Extreme pressure property: pressure in the thin lubrication gap can be 10000bar (高极压性) 8.2.1 Lubricants Characteristics and Additives （润滑剂特性及润滑剂添加剂）
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Page 2 10/23 同济大学汽车学院 Additive type Function V.I. improvers (粘度改善剂) Improve viscosity temperature behavior Detergents (清洁剂) Keep engine clean, neutralize acids Dispersants (分散剂) Disperse soot, aging products, foreign materials, prevent deposits Oxidation inhibitors (抗氧化剂) Prevent oil oxidation and thickening Corrosion inhibitors (抗腐蚀剂) Prevent corrosion Nonferrous metal deactivators (有色金属抗活化剂) Prevent oxidation and oil thickening Friction modifiers (摩擦改进剂) Reduce friction loss Wear reducer (EP additives) (抗磨损剂) Reduce or prevent wear Pour point depressant (降凝剂) Improve flow properties at low temperatures Foam inhibitor (泡沫抑制剂) Reduce or prevent the formation of foam Lubrication Oil Basic liquids Additives for lubricants (see table below) Mineral Basic Oils （矿物质油）: conventionally used Synthetic Basic Liquid （合成油）：high-performance multigrade oil 11/23 同济大学汽车学院 • SAE (Society of Automotive Engineers)introduced a binding classification for engine oil viscosity(1911) A total of 12 classes: Higher numbers indicates higher viscosity and is suitable for higher engine speed Engine oils used today normally covers the viscosity requirements of several SAE grads, and is indicated as “multigrade oil”(多粘度等级), such as SAE5W/20, SAE10W/30 SAE5W/20 has viscosity of SAE5W in winter and viscosity of SAE20 in summer, therefore could be used throughout whole year 8.2.2 Classification of Lubrication Oil （润滑油分类） Six for the winter: SAE0W-SAE25W Six for the summer: SAE20-SAE60 12/23 同济大学汽车学院 • API (American Petroleum Institute) classifies lubrication oil according to its performance and appropriate applications • Domestic classification adopt the ISO method according to GB/T7631.3- 1995 • Greases (润滑脂) By mixing lubrication liquids with densifier, one can get a solid or semisolid product Stable and immobile(不可流动), suitable for open type or sealless (无密封) friction parts S series: for gasoline engines, classified from SA to SN C series: for diesel engines, classified from CA to CE (Performance increases alphabetically) Gasoline engines: classified from SC to SH Diesel engines: classified as CC, CD, CD-2, CE, CF-4 Two stroke gasoline engines: ERA to ERD 13/23 同济大学汽车学院 • Function: Oil delivery, pressure boosting （供油、增压） • Classification: 8.3 Oil Pump （机油泵） Oil Pump Video Gear Pump (齿轮泵) Rotor Pump (转子式) Internal gear pump（内接齿轮式） External gear pump（外接齿轮式） 14/23 同济大学汽车学院 8.3.1 External Gear Pump （外接式齿轮泵） • Advantages: high efficiency, simple structure, reliable, low power loss • Disadvantages: requires intermediate transmission (中间传动装置), larger size, high manufacture cost, uneven oil supply (供油不均匀) 15/23 同济大学汽车学院 8.3.2 Internal Gear Pump （内接式齿轮泵） • Advantages: No intermediate transmission, less components, lower cost, smaller size • Disadvantages: low volume efficiency (because of the crescent (月牙形)), higher power loss 16/23 同济大学汽车学院 8.3.3 Gerotor Pump （转子泵） • Advantages: Compact structure, smaller size, less weight, even oil supply, lower cost , widely used in small engines with light load 17/23 同济大学汽车学院 • Relief Valve（限压阀） High oil pressure would lead to engine power loss Relief valve is placed on oil pump cap（油泵端盖） Relief valve opens when oil pressure greater than 0.6MPa, and let part of oil goes back to oil inlet, and close when oil pressure lower than 0.1MPa • Bypass Valve （旁通阀） Placed in parallel with （并联）full-flow filter （细滤 器）between oil pump and main oil channel When filter is blocked up, pressure difference between inlet and outlet of filter would rise When pressure difference reaches 0.15MPa, bypass valve opens to guarantee enough oil delivered to engine 18/23 同济大学汽车学院 8.4 Oil Filter （机油滤清器） • Oil filters: Video Intake screen (集滤器) Full-flow oil filters (粗滤器): in series with (串联) main oil channel Bypass oil filters (fine filter)(细滤器): in parallel with (并联) main oil channel, bypass 10~30% oil • Intake screen Prevent large metallic particles into the oil pump floating type (浮式): floating on oil surface, draws cleaner oil at the top, lower oil pressure because of foam (泡沫) suction Stationary type (固定式): placed under oil surface, prevent foam drawing, more reliable, simpler structure
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Page 3 19/23 同济大学汽车学院 • In series （串联）with oil pump and main oil channel • Types: • Bypass valve exist incase filter element is block up and no oil is delivered to engine Metal elements (金属片式) Paper elements （纸筒式） Saw powder elements （锯末式） 8.4.1 Full-Flow Oil Filters （粗滤器） 20/23 同济大学汽车学院 • Hardly used because of its weight, complex structure, and production cost • Most widely used • Light, compact, simpler structure with low cost • Low filtration resistance (过滤阻力) • Easy maintenance • Composite filter elements (复合材料滤芯) • Low filtration resistance • Long service life 21/23 同济大学汽车学院 • Removing element for ultrafine particles (超微颗粒) • Particularly for high-mileage diesel engines with high soot level • In parallel with main oil pass (high filtration resistance) • Classification Net-type filter: Dilemma between filtration capacity (滤清能力) and through capacity (通过能力) Centrifugal filter: most widely used 8.4.2 Bypass Oil Filters (Fine Oil Filter) （细滤器） 22/23 同济大学汽车学院 • Consist of metal or plastic • Rotation speed up to 10000 r/min • Extremely compact filter cake ( 滤饼)，easy maintenance 23/23 同济大学汽车学院 • Control oil temperature within appropriate range under high engine load • Forced cooling device • Classification Wind cooled: Placed before engine radiator, make use of the cooling fan Water cooled: Placed in engine cooling channel • Gain heat from cooling water during cold start • Dissipate heat to cooling water under high load • Compact structure, widely used in passenger cars • Lubrication oil goes into heat transmitter after it leaves oil filter 8.5 Heat Transmitters (Oil cooler) （机油冷却器） 1、Heat transmitter 机油冷却器 2、Pressure switch 机油压力开关 3、Oil filter 机油滤清器 4、Filter element 机油滤清器滤芯