UNIT ONE 一、单词)
automobile 〈美〉小客车(汽车 tremendously 惊人?可怕?的(非常 crore ?印英?一千万 allied 有关的(相近的
construction 建筑(结构(构造 automotive 汽车的(自行的 vehicle 车辆(运输车辆 experienced 有?实践?经验的(熟练的 diagnose 诊?判?断(确定(断定 trouble 故障(事故?扰乱(损坏 component 部?元(组(零(构?件(部分 transmission 变速器(变速箱(传动系 differential 差?动(速?(差分?动?器 suspension 悬架(悬架装置 airconditioner 空气调节器(空调装置 classification 分类(分级 articulated 铰接的(有活节的 conventional 惯例的(常规的(传统的 majority 多数(大多数(半数以上 passage 通过(经过(推移 arrangement 布置(排列(分布 digital 数字的(计数的(指状的 denote 指示(表示(意味着 mechanism 机构(机械(机械结构 connection 连接(接合(接头 cabin 驾驶室(客舱 retractable 可收回的(可缩进的 automatically 自动的(自然而然的 abnormal 反常的(不正常的 tyre 轮胎(车胎?装轮胎在…上 introduction 引进(传入(采用 adhesion 粘着(附着(附着力 scooter 低座小摩托车(小型摩托车 transport 运输(运输工具 minibus 小型公共汽车?四座四人? accumulator 蓄电池(储压器 crane 起重机(吊车?用起重机搬运 wheeler 有轮车(有…轮的东西 motion 运动(移动 reciprocate 往复运动(前后转动(来回 pneumatic 气动的(风动的(空气推动的 convertible可改变的(可变换的
all over the world 全世界 manufacturing process 生产流程(制造过程 lawn mover 剪草器(割草机 snow remover 扫雪车
saturation point 饱和点 single-unit vehicle 整体式车身车辆(承载式车辆 arrange for 安排(准备 on the other hand 另一方面 with respect to 关于(就…而论(根据
be classified as 分成…类 delivery van 厢式送货车
Types of Automobiles
thThe automobile industry is a fast developing industry. Form the later 18 century
when the first automobile was put on road, this industry has developed tremendously. Now there are thousands of factories all over the world manufacturing numerous types of automobiles. This industry employs crores of men and women directly and indirectly in allied industries. The automobile engines are also being used in engine powered machines for agriculture, construction and manufacturing processes. Various types of small engines are also being used in lawn movers, power saws, snow removers and similar equipment. The automobile industry is a developing and demanding industry which does not find its end or saturation point. There is a great demand for varied types of automotive products, vehicles and engines. There is also a great demand for trained and experienced persons in this industry for diagnosing motor vehicle troubles, repairing and replacing engines components, transmissions, propeller shafts, differentials, axles, steering system components, brake system components, suspension components, air conditioners, heaters, body and glass work.
There are numerous types of automobiles used in the world. There are in general three main classifications of the various types of vehicles.
(1) The single-unit vehicles or load carriers.
(2) Articulated vehicles.
(3) The heavy tractor vehicles.
Single-unit vehicles are of conventional four-wheel type. The great majority of vehicles are of two axle design, In these vehicles the front axle is a steering non-driving axle and the rear axle is the driving axle. With the passage of time, a great many changes have taken place in the number of axles and the driving arrangements.
In this classification, digital terms like 4×2, 4×4, 6×4etc,are commonly used. The
first figure denotes the total number of wheels and the second figure the number of driving wheels.
A lower powered three-wheeler with a single steering wheel in front and a conventional rear driving axle is an example of articulated vehicles. It has a greater handing ability in awkward places. It can be turned about its own tail due to the three-wheel construction. The coupling mechanism between semi-tailer and tractor in most of these vehicles is arranged for automatic connection and coupling up necessitating only its reversing into the position. But for uncoupling operation, a lever is provided within the driver‟s cabin to reverse the whole
process. A pair of retractable wheels in front are also provided. Along with the coupling or uncoupling operation, they can be raised or lowered automatically.
To move heavy loads, heavy tractor or independent tractor vehicles commonly operate in pair either in tandem or as „puller‟ and „pusher‟. A special consideration is made in respect
of the drive to the front wheels in all-wheel-drive vehicles. We know that the front wheels are to travel farther than the rear wheels on every band. The wind-up produced by this difference of travel over-stresses the transmission system. To avoid this a great necessity of some form of differential or its equivalent has been felt to provide it the front and rear drives. It has been seen that if the conditions are not very abnormal, sufficient amount of tyre slip taking place under running conditions would release these stresses completely.
An all-wheel drive is better than the introduction of differentials between the various axles. It provides adhesion under the worst possible conditions. On the other hand, the drive to all the other axles is liable to be lost if any one axle or group of axles loses adhesion.
Types of automobiles. There are numerous types of automobile found in different parts of the world. With respect to different purposes, the various types of automobiles are classified as under:
?. With respect to the use:
(a)Auto-cycles and Moppets. (b) Scooters and Motor cycles. (c) Cars, Station Wagons and Pick-ups. (d) Lorries(Buses) and Trucks. (e) Tractors.
?. With respect to capacity:
(a) Heavy Transport Vehicle or Heavy Motor Vehicles: Tata , Leyland. (b) Light Transport Vehicles, or Light Motor Vehicles(Cars, Jeeps, Scooter/Motor cycles). (c) Medium Vehicles: Tempo, Minibus, Station Wagon.
?. With respect to the fuel used:
(a) Petrol Vehicles: Cars, Scooters, Motor Cycles. (b) Diesel Vehicles: Tata, Leyland Vehicles, Mercedes Car. (c) Gas Vehicles: Coal-gas, Gas Turbine or Producer-Vehicles. (d) Electric Vehicles-using electric storage batteries or accumulators to drive electric motors attached to the front or rear wheels, e.g. Heavy cranes. (e) Steam Vehicles-It is now obsolete.
?. With respect to the make:
(a) Leyland, Tata. (b) Ambassador, Fiat(Premier-President), Standard, Herald etc.(c) Vespa/Bajaj, Raj, Hans, Rajdoot, Royal Enfield, Vijay Delux, Vijay Kesari, Priya.
?. With respect to wheels and axles:
(a) Two Wheelers: Motor Cycles/Scooters. (b) Three wheelers: Tempos, Auto
Rickshaws. (c) Four Wheels: Cars, Jeeps, Buses, Trucks(6 Tyres)etc. Buses and Trucks have six tyres out of which four are carried on the rear wheels for additional traction. (d) Axle 6 wheelers (10 tyres) Vehicles: Shaktiman, Dodge.
?. With respect to the drive:
(a) Left hand drive-most of the American vehicles.
(b) Right hand drive-most of the Indian vehicile.
(c) Fluid drive-Vehicles using Fluid Coupling Engine and Transmission.
(d) Front wheel drive-volks Wagon, Skoda, Austin.
(e) Rear wheel drive-most of the Indian vehicles.
(f) All wheel drive-Jeep 4×4.
?. With respect to motion: (a) Reciprocating-piston Engines. (b) Rotary-wankel Engine, Gas Turbine.
?. With respect to the suspension: (a) Conventional-Leaf Spring. (b) Independent-Coil, Torsion bar, Pneumatic.
?. With respect to the body and number of doors: (a) Sedan-Two doors, four doors. (b) Convertible-Jeep. (c) Station Wagon. (d) Delivery Van.
?. With respect to transmission:
(a) Conventional-Most of Indian vehicles.
(b) Semi-automatic-Modern British vehicles.
(c) Automatic-American Vehicles.
internal 内部的 combustion 燃烧(焚烧
reciprocating 往复移动 stratified 重叠式的 cylider 气缸(液压缸 iron 铁(铁制品 aluminum 铝(铝制品 casting 铸造 passage 通道 inline 直线的(一列的(排成列的 attach 连接 pin 轴销 wristpin 轴颈 transmit 转换成(传动(传输 mount 安装(固定(装配 bearing 轴承(支承面 crankshaft 曲轴 diameter直径 bore内径 displacement 排气量(气缸工作容积
specification 参数 stroke 行程(冲程
intake 进气 compression 压缩
power 作功 exhaust 排气
valve 阀门(气门 overlap 进气们和排气们同时打开的时间
inlet 进气(进气口(引入 t.d.c. 上止点
b.d.t. 下止点 throttle 节气门
ignite 点火 spark 火花(电火花(闪光
gap 间隙(空隙(火花塞间隙 combine 混合(联合
incline 倾斜(下降 apart 相隔(分开
version 形式(方案(版本 horizontally 水平地(平卧地
二、Phrases and Expressions
build upon 把……寄托于……(依赖于…… water jacket 水套
cylinder block 气缸体 combustion chamber 燃烧室
oil pan(oil sump) 油底壳(油盆 rotation motion 旋转运动
connecting rod 连杆 spark plug 火花塞
push out 排出 up and down 上下
depend on 取决于(依赖 in honor of 向……表示敬意
compression ratio 压缩比 be forced down 被压下
either…or… 既……又…… the more…the more 越……越……
Engine Operating Principles
Most automobile engines are internal combustion, reciprocating 4-stroke gasoline engines, but other types have been used, including the diesel, the rotary (Wankel), the 2-stroke,and the stratified charge.
Reciprocating means “up and down” or “back and forth”. It is the up and down action
of a piston in the cylinder that produces power in a reciprocating engine. Almost all engines of this type are built upon a cylinder block, or engine block. The block is an iron or aluminum casting that contains engine cylinders and passages called water jackets for coolant circulation. The top of the block is covered with the cylinder head, which forms the combustion chamber. The bottom of the block is covered with an oil pan or oil sump.
Power is produced by the linear motion of a piston in a cylinder. However, this linear motion must be changed into rotary motion to turn the wheels of cars of trucks. The piston is attached to the top of a connecting rod by a pin, called a piston pin or wrist pin. The bottom of the connecting rod is attached to the crankshaft. The connecting rod transmits the up-and-down motion of the piston to the crankshaft, which changes it into rotary motion. The connecting rod is mounted on the crankshaft with large bearings called rod bearings. Similar bearings, called main bearings, are used to mount the crankshaft in the block. Shown in Fig.1-1.
The diameter of the cylinder is called the engine bore. Displacement and compression ratio are two frequently used engine specifications. Displacement indicates engine size, and compression ratio compares the total cylinder volume to compression chamber volume.
The term “stroke” is used to describe the movement of the piston within the cylinder, as well as the distance of piston travel. Depending on the type of engine the operating cycle may require either two or four strokes to complete. The 4-stroke engine is also called Otto cycle engine, in honor of the German engineer , Dr.Nikolaus Otto, who first applied the principle in 1876. In the 4-stroke engine, four strokes of the piston in the cylinder are required to complete one full operating cycle. Each stroke is named after the action it performs intake ,compression, power, and exhaust in that order, shown in Fig1-2.
1. Intake stroke
As the piston moves down, the vaporized mixture of fuel and air enters the cylinder through the open intake valve. To obtain the maximum filling of the cylinder the intake valve
oooopens about 10 before t.d.c., giving 20 overlap. The inlet valve remains open until some 50
after b.d.c. to take advantage of incoming mixture.
2. Compression stroke
The piston turns up, the intake valve closes, the mixture is compressed within the combustion chamber, while the pressure rise to about 1Mpa,depending on various factors including the compression ratio, throttle opening and engine speed. Near the top of the stroke the mixture is ignited by a spark which bridges the gap of the spark plug.
3. Power stroke
The expanding gases of combustion produces a rise in pressure of the gas to some 3.5Mpa,and the piston is forced down in the cylinder. The exhaust valve opens near the bottom of the stroke.
4. Exhaust stroke
o before b.d.c. , allowing The piston moves back up with the exhaust valve open some 50
the pressure within the cylinder to fall and to reduce „back‟ pressure on the piston during the
exhaust, and the burned gases are pushed out to prepare for the next intake stroke. The intake valve usually opens just before the exhaust stroke.
This 4-stroke cycle is continuously repeated in every cylinder as long as the engine remains running.
A “2-stroke”engine also goes through four actions to complete one operating cycle. However ,the intake and the compression actions are combined in one stroke ,and the power and exhaust actions are combined in the other stroke. The term 2-stroke cycle or 2-stroke is preferred to the term 2-cycle,which is really not accurate.
In automobile engines ,all pistons are attached to a single crankshaft. The more cylinders an engine has ,the more power strokes produced for each revolution. This means that an 8-cylinder engine runs more smoothly because the power strikes are closer together in tin\me and in degrees of engine rotation.
The cylinders of multi-cylinder automotive engines are arranged in one of three ways.
1) Inline engines use a single block of cylinder . Most 4-cylinder and any 6-cylinder engines are of this design. The cylinders do not have to be vertical. They can be inclined to either side.
2) V-type engines use two equal banks of cylinders , usually inclined 60 degrees or 90 degrees from the each other . Most V-type engines have 6 or 8 cylinders , although V-12 engines have been built.
3) Horizontally opposed or “pancake” engines have two equal banks of cylinders 180
degrees apart . These space saving engine designs are often air-cooled , and are found in the Chevrolet Carvair , Porsches , Subaus , and Volkswagens . Subaus‟ design is liquid cooled.
Late-model Volkswagen vans use a liquid-cooled version of the air cooled VW horizontally Opposed engine.