U5 THE LUBRICATION SYSTEM润滑系 附扩展第5篇.doc

UNIT 5 THE LUBRICATION SYSTEM学习目标:1. 掌握润滑系相关的专业术语、词汇。2. 能对润滑系相关的资料进行中英文互译。3. 能进行相关内容的阅读和翻译。TEXT A THE LUBRICATION SYSTEM1. Lubrication Principles Reducing friction to minimize wear and loss of power is the primary job a lubrication system must perform1. Residual oil on engine parts also provides lubrication for engine start-up.The engine oil forms a seal between the pistons, rings, and cylinders. It also helps to cool engine parts. Without the cleaning acting of the lubricating system, carbon and varnish build up would be excessive. The engine oil also absorbs the shock and dampens the noise of moving parts.How successful the lubrication system is in performing all these functions depends on a number of factors and conditions. There must be an adequate supply of good-quality lubricant delivered to all moving engine parts under sufficient pressure to provide hydrodynamic lubrication for rotating parts and oil adhesion to surface subject to sliding friction.2. Parts of the Pressure-Lubrication System2.1 Oil Pan The oil pan bolts under the engine block, where it seals off the bottom of engine. Shaped like a trough, this sheet-metal pan serves as the reservoir for about 5 quarts of oil. As oil flows from the engine, it drains downward into the oil pan. The oil pump sucks oil from the lowest part of the oil pan, the oil sump. Many oil pans have baffles, which are thin metal partitions. These keep the oil in the sump when the car corners hard or brakes suddenly. A drain plug at the bottom of the sump allows oil to be drained from the engine. The oil-pan gasket fits between the oil pan and the bottom of the engine block. In most engines, the oil circulates in the engine, and then returns to the pan. It stays in the oil pan until drawn back into the engine by the oil pump. During operation, the sump usually holds 2 to 3 quarts of oil. The rest of the oil moves through the passageways of the lubrication system. With the engine off, the pan holds about four quarts of oil. The fifth quart is in the oil filter. Because a pool of oil always rests in the sump, the type of lubrication system is called a wet-sump oiling system. A dry-sump oil system is used in many racing engines. This system has a separate storage tank for the oil. A second oil pump draws oil from the oil pan as the oil drains from the engine. As a result, a dry-sump system can circulate more oil through the engine than a wet-sump system.2.2 Oil PumpThere are two general types of automotive-engine lubricating-system oil pumps, gear and rotor. The gear-type oil pump uses a pair of gears. As they rotate, the spaces between the teeth are filled with oil from the oil inlet. Then, when the gears mesh, the oil is forced out through the oil outlet. The rotor-type oil pump has an inner and an outer rotor. The inner rotor is driven and turns the outer rotor. The spaces between the rotor lobes become filled with oil. When the lobes of the inner rotor move into the spaces in the outer rotor, the oil is squeezed out through the outlet. Oil pumps are usually driven from the engine camshaft by the same spiral gear that drives the ignition distributor. The oil intake for the oil pump is attached to a float in some engines. This floating intake takes oil only from the top of the oil in the oil pan. Since dirt particles sink, the top oil is the cleanest.2.3 Oil Filter All automotive-engine lubricating systems have an oil filter（Figure5-1）. Oil circulates through this filter. In the filter, an element of filtering material traps particles of foreign material. This helps to keep the engine oil clean and to prevent particles from entering the engine. Oil filters are of two types. Those that filter part of the oil from the oil pump are caller bypass oil filters. Those that filter all the oil from the oil pump are caller full-flow oil filters. Some turbocharged diesel engines have both types of filter.Figure 5-1 oil filter Full-flow filters have a spring-loaded bypass valve. It protects the engine from oil starvation if the filter becomes clogged. If this happens, the valve is opened by the increased pressure from the pump trying to push oil through the filter. With the valve open, oil bypasses the filter. However, before this happens, the filter should be changed. The oil circulating with the valve open is not filtered and engine damage could result.3. Engine LubricationAn internal combustion engine would not run for even a few minutes if the moving parts were allowed to make metal-to-metal contact. The heat generated due to the tremendous amounts of friction would melt the metals, leading to the destruction of the engine2. To prevent this, all moving parts ride on a thin film of oil that is pumped between all the moving parts of the engine. Once between the moving parts, the oil serves two purposes. One purpose is to lubricate the bearing surfaces. The other purpose is to cool the bearings by absorbing the friction-generated heat. The flow of oil to the moving parts is accomplished by the engines internal lubricating system. Figure 5-2 shows a engines lube oil circuit schematic.Figure 5-2 lube oil circuit schematicThe oil pump is of the gear type, consisting essentially of two gears in mesh and requires no attention or adjustment. It is housed in the sump, being driven by a shaft and skew gearing from the camshaft.Oil from the sump is delivered at full pressure to all main bearings and camshaft bearings through gallery pipes and drillings in the cylinder block. The big-end bearings are fed from the main bearings via passages in the crankshaft.Lubrication for the timing chain is supplied an two points, by a feed from the front camshaft bearing into the periphery of the camshaft chain wheel and also by oil fed through the hollow shaft on which the timing chain jockey pulley is mounted arid thence through holes in the circumference of the jockey pulley.The inlet and exhaust rocker shafts are hollow, the inlet shaft being fed with oil from the rear of the main gallery pipe via an external pipeline, whilst that for the exhaust rockers and inlet followers is supplied via drillings from the center camshaft bearings. Each rocker and follower receives its oil through small holes drilled in the rocker shafts and in turn they are themselves also drilled, so that the oil finds its way through them and thence out again to lubricate the points of contact with the valves, push-rods and camshaft3. The distributor drive shaft is lubricated with oil fed from the exhaust rocker shaft via a hollow bolt.Surplus oil from the inlet valve gear returns through the cylinder casting and that from the exhaust valve gear direct to the sump. 4. Lubrication Oils Motor oils for automobile engines fall into two basic categories: petroleum-based oils and synthetic oils. Petroleum-based oils, however, contain a variety of additives; so in fact they, too, are partly synthetic. The oil lubricates moving parts in the engine to minimize wear. Clearances between moving parts are filled with oil. The parts move on the layers of oil to minimize wear. Parts moving on layers of oil require comparatively little power to move them. The oil minimizes friction horsepower. The circulating oil helps cool the engine. As the oil moves through the engine, the oil gets hot. Then, when it drops down into the oil pan, which is cooler, the oil gives up this heat. So the oil is continually removing heat from the engine.The oil also helps absorb shock loads. When the power stroke starts, a force of as much as 4000 pounds is suddenly imposed on the rod and main bearings4. The layers of oil in the bearing clearances resist squeezing out, acting as cushions to absorb the sudden load.The oil helps form a gastight seal between piston rings and cylinder walls. In forming this, the oil helps to reduce blowby.The oil acts as a cleaning agent. As it circulates through the engine, the oil picks up particles of metal and carbon and carries them back down into the oil pan. Larger particles fall to bottom of the oil pan. Smaller particles are filtered out by the oil filter.NEW WORDS lubrication lu:brikein n. 润滑；润滑作用；润滑油principle prinspl n. 原理，原则；主义，道义；本质，本义；根源，源泉residual rizidjul,rizidul n. 剩余；残渣 adj. 剩余的；残留的varnish v:ni n. 虚饰；光泽面；亮光漆，清漆 vt. 装饰，粉饰；在上涂清漆；使有光泽buildup bildp n. 组合；增强；发展；形成；树立名誉quart kw:t n. 夸脱（容量单位，等于14加仑或2品脱）；一夸脱的容器excessive iksesiv adj. 过多的，太大的，过分的；过度的，极度的，放纵的dampen dmpn vt. 使降低；减少；抑制；使扫兴；使沮丧，使消沉，给泼冷水；潮湿，弄湿，沾湿，使湿润partition p:tin n. 分开；隔开；划分；分配 隔开物；隔墙；隔板；区分线；区分物 部分；隔开部分；隔开的房间gum m n.树胶；橡皮；口香糖 vt. 使有粘性；用胶粘，涂以树胶rough trf,tr:f n. 槽，饲料槽，和面槽；洗槽，水槽；槽形物baffle bfl vt. 使困惑；使受挫折；用挡板控制 vi. 做徒劳挣扎 n. 挡板；困惑sump smp n. 油底壳，机油箱；污水坑；水坑 vi. 挖深（渠道，井筒等）turbocharge t:but:d vt. 用涡轮给增压clog kl vt.阻塞，堵塞(管子、道路等)；障碍，妨碍，阻碍；挤满，填满 vi.发生阻碍；堵塞，堵住；塞满：粘住，粘在一起；凝成一块 n.障碍物；阻碍；妨碍porosity p:rsiti, pursiti n. 多孔性；有孔性；多孔的东西；多孔物质；多孔部分；多孔结构periphery prifri n.周界线(尤指圆周)；周边；外围；周围；边缘；界限 外表面(尤指圆体的外面)，外部；次要部分；无关紧要部分，边缘科学synthetic sinetik adj. 综合的(相对于 analytic) ；合成的，人造的；合成燃料的n. 合成物；合成纤维；合成剂antiscuff ntiskf n.磨损overhaul uvh:l,uvh:l vt. 解体检修，拆修，大修：彻底检查，仔细检验：全面修订；彻底革新(或改革)：n.拆修，大修全面检查；详细检验全面修订；底革新(或改革)neutralize nju:trlaiz vt. 抵销；使中和；使无效；使中立 vi. 中和；中立化；变无效agitation ditein n. 激动，兴奋，煽动，搅动PHRASES AND EXPRESSIONS oil Pan 油底壳dry-sump 干油底壳wet-sump 湿油底壳pickup tube 机油吸油管filter screen 滤网full-flow filtering system 全流式滤清系统pressure-relief valve 安全阀 泄压阀gear type oil pump 齿轮式机油泵jockey pulley 张紧轮，导向轮corrosion inhibitor 防腐剂detergent-dispersant 清洁分散剂viscosity index 粘度指数foam inhibitor 泡沫抑制剂KEY VOCABULARYabsorbbs:b, b z:bvt.1.吸收；吸引；承受；理解；使全神贯注: Blotting paper absorbs ink. .吸墨水纸吸墨水。A sponge absorbs water. 海绵吸水。2.吸引的注意；使全神贯注，使专心致志，占去(注意力、精力、兴趣、时间等)： She was absorbed in study. 她专心学习。He was so absorbed in a book that he did not hear the bell. 他如此专心致志地读书以致没听见铃响。This job absorbs all of my time. 这项工作占去了我的全部时间。She was absorbed in her reading. 她在专心读书。3.理解；掌握： Can your brain absorb all this information? 你的脑袋能吸收这全部信息吗?4.吸收(食物、思想、文化等)；同化(民族、语言或成分等)，把并入，使合并： The small firms were absorbed into large cartels. 这些小公司被大企业联盟兼并了。The empire absorbed many small nations. 该帝国吞并了许多小国。5.承受，忍受；经受： to absorb the changes 经受住变革6.负担，承担(费用、经费)： to absorb the cost 承担费用The company will absorb all the research costs. 这家公司将承担全部研究经费。7.消减(振动)，缓冲(震动、颠簸等)： Cork ceilings absorb sound. 软木制的天花板能减少回音。to absorb shock 缓冲震动8.吸收(光、热、声音等)： Light rays are absorbed by black surfaces. 光线被黑色表面吸收(而无反射)。to absorb sound and light 吸收声音和光9. (大量)收买，买进，收购进；(市场)吸纳，接受(商品等)： to absorb a shop 盘进一家商店The market absorbed all the computers we could build. 市场吸纳了我们所能生产的全部电脑。clog kl vt.1.阻塞，堵塞(管子、道路等:The expressway was clogged with automobiles. 这条高速公路被汽车堵塞了。2.障碍，妨碍，阻碍：Commerce was clogged with various restrictions. 各式各样的限制阻碍了商业的发展。3.挤满；填满：The teeth of the saw were clogged with sawdust. 锯齿间塞满了锯末。vi.1.发生阻碍；堵塞，堵住；塞满：These streets often clog during the rush hour. 这几条大街在交通高峰时间常常发生交通堵塞。The sewer in the kitchen clogs easily. 厨房的下水道很容易堵塞。2.粘住，粘在一起；凝成一块:Oil soon clogs in cold weather. 天气冷时油很快就凝成一块。NOTES TO THE TEXT1. Reducing friction to minimize wear and loss of power is the primary job a lubrication system must perform.减少摩擦，降低磨损和动力损失是润滑系统必须完成的主要工作。Reducing friction to minimize wear and loss of power现在分词作主语2. The heat generated due to the tremendous amounts of friction would melt the metals, leading to the destruction of the engine.由于大量的磨损产生的热量将会烧蚀金属，导致发动机损坏。generated due to the tremendous amounts of friction被动语态做定语3. Each rocker and follower receives its oil through small holes drilled in the rocker shafts and in turn they are themselves also drilled, so that the oil finds its way through them and thence out again to lubricate the points of contact with the valves, push-rods and camshaft. 每个摇臂和挺杆从摇臂轴上的小孔中得到机油，然后机油进入它们本身带有的孔道；通过这些孔道出来后，再去润滑与之相连的气门、推杆和凸轮轴。4. When the power stroke starts, a force of as much as 4000 pounds is suddenly imposed on the rod and main bearings.做功行程开始时， 4000磅的力突然作用在连杆和轴瓦上。TEXT B REPLACING THE OIL AND THE OIL FILTER Replacing the oil is an easy way to keep an engine working well1. Pouring a good grade of clean oil into the engine every 4000 to 6000 miles will prolong life. Automobile makers set oil-replace intervals for their cars. Follow their recommendations. Recently, the interval between oil changes has been lengthened. With better oil and better engines, the oil can be used longer without damaging the engine. Also, unleaded fuels do not dirty oil the way leaded gasoline does2. Remember, oil filters hold 1 quart of oil at all times. So if you drain the oil but leave in the old filter, you are mixing four quarts of fresh oil with one quart of dirty oil. For this reason it is a good idea to change the filter every time you change the oil. Replacing the oil and the filter are easy. Put the car on a lift. Or, drive the car onto a portable car ramp, and block the wheels. Place a pan under the drain plug in the bottom of the oil pan. Remove the drain plug to drain the dirty oil into the pan（Figure5-3）.Figure 5-3 remove the drain plug Warm the engine before replacing the oil. Warm oil flows more freely and carries more dirt with it. Be careful when working on an engine that has been running for a long time. Oil gets quite hot. You could burn yourself in replacing the oil on a hot engine. Once you have drained the oil, clean the drain plug and replace it in the pan. Do not over-tighten the plug. Otherwise, may damage the oil pan. Remove the oil filter. Some filters are removed from underneath the car, and others from above. Unscrew the filter with an oil-filter wrench（Figure5-4）.Figure 5-4 unscrew the filterBefore installing a new filter, make sure the oil-filter mounting pad is clean. Wipe it with a soft dry rag. Next, to assure a proper seal, coat the rubber seal with a light coating of oil. Be sure that the new filter is the same size and type an the old one. If the oil filter fits onto the engine with the mounting surface up, you can fill the filter with an much oil as it can hold. This keeps the engine from being “starved” for oil when it first starts. Tighten the new filter by hand. Do not use the oil-filter wrench.Intervals that the oil and filter are replaced should be followed as outlined in the vehicle owners manual or shop service manual. The SAE rating and the service rating of the oil used, should comply with the vehicle manufacturers recommendations.The frequency of oil and filter replaces may vary depending on the type of service the vehicle is required to provide. Under severe operating conditions, such as driving in dusty conditions, trailer towing, extensive idling, frequent short trips (especially in cold weather), and sustained high-speed driving (especially in hot weather), more frequent replacing-oil are required.In some cases, manufactures may recommend a special antiscuff additive be used with the engine oil after an engine overhaul or after severe service3. Special conditions may have to be observed to use such additives. The manufacturers recommendations should be followed in every case. NEW WORDS prolong prl, l: vt. 拖延；延长block blk n. 块；街区；障碍物；大厦 vt. 阻塞；阻止；限制 adj. 成批的，大块的；交通堵塞的drain drein vi. 排水；流干 vt. 喝光，耗尽；使流出；排掉水 n. 排水；消耗；下水道，排水管plug pl n. 栓；插头；塞子 vi. 塞住；用插头将与电源接通 vt. 塞住；插入；接插头wipe waip vt. 擦；涂上；消除 vi. 擦;打 n. 擦拭；用力打wrench rent n. 扳手，扳钳；歪曲；猛扭；扭伤；痛苦 vt. 猛扭；扭伤；曲解；折磨 vi. 猛扭；扭伤；猛绞ramp rmp n. 斜坡，坡道；敲诈 vi. 蔓延；狂跳乱撞；敲诈 vt. 敲诈；使有斜面underneath ,ndni: prep. 在的下面；在的形式下；在的支配下 adv. 在下面；在底下 n. 底部；下面 adj. 下面的；底层的PHRASES AND EXPRESSIONS unleaded fuel 无铅汽油over-tighten 过紧SAE=Societ