汽车专业英语 3 Power train
汽车专业英语 Specialty English for Automobile
张志飞
E-mail: cquzzf@https://www.360docs.net/doc/e29540448.html, Tel: 135********
Chapter 3 Power train
?overview : a general review or summary of a subject 概述 综述 ?The function of the power train of an automobile is to provide the forces necessary for locomotion. The forces are produced by the conversion in the IC (Internal combustion) engine of the chemical energy in liquid fuels (or in the electric motor of electrical energy) into the energy of motion (kinetic energy). ?Locomotion: movement or the ability to move from one place to another
–he preferred walking to other forms of locomotion.
Versions of power train
?Fairly even ?Universal joint ?Longitudinal // Transverse ?Occasionally occurring, appearing, or done infrequently
and irregularly
?Permanent or selectable ?Each tire is evenly abraded ?capability ?Grip ?Compact layout ?Driving drive driven ?Axle wheel: 车桥 车轮 steering axle ?Interior room // exterior
?Equilibrium: state in which opposing forces or influences are balanced ?Rolling /climbing /acceleration /air Resistance ?Drag: the longitudinal retarding force exerted by air or other fluid surrounding a moving object ?Quantity : the figure or symbol representing this ?Face area: 迎风面积 ?Dynamic tire radius：滚动半径 rolling static radius ?Mass moment of inertia ?Incline ?Rad: radian
Element of the power train
1 － Clutch 2 2 － Transmission 3 3 － UJ(Universal (Universaljoints) joints) 1 － Clutch － Transmission － UJ 4 － Driveshaft shaft 5 5 － Finaldrive drive 6 6 － Differential 7 7 － Half-shaft 4 － Drive － Final － Differential － Half-shaft
?Driving away 开走 ?Guarantee optimum operation of the engine (electric motor) in terms of fuel consumption and exhaust emissions. 保证，在……方面 ?Standstill, driving away and power interruption are made possible by operation the clutch. Two types of toothed-gear transmission are predominant: spur-gear transmissions of the countershaft type as manually transmission, and planetarygear transmissions as power-shift transmissions. ? cornering // Uniform distribution
3.2 Clutches
? Dry friction clutch
– Task: a piece of work to be done or undertaken
① It disengage the engine from transmission to allow for gear changing ② It is a means for gradually engaging the engine to the driving wheels
When a vehicle is to be moved from rest the clutch must engage a stationary transmission shaft with the engine; this must be rotating at a high speed to provide sufficient power or else the load will be too great and the engine will stall (come to rest).
–To do 不定式作定语，可被动式，可主动式。但当考虑的是必 须有人去完成某件事时，用主动形式，若强调事情本身必须完 成，则用被动。如：
? There are many books to read/ to be read. 有好多书要读。
–Stall：an instance of an engine, vehicle, aircraft, or boat stalling
当汽车原地起步时，离合器把静止的变速器轴同发动机接 合起来，此时发动机必须高速旋转以提供足够大的功率， 否则载荷过大将引起发动机熄火。
To start the engine, the driver must depress the clutch pedal. This disengages the transmission from the engine. To move the car, the driver must reengage the transmission to the engine. However, the engagement of the parts must be gradual. An engine at idle develops little power. If the two parts were connected too quickly, the engine would stall. The load must be applied gradually to operate the car smoothly. ?Solid coupling device: 刚性 ? Driving member ? Driven member ? Operating members
The driving member（主动部分） The driving member consists of two parts: the flywheel and the pressure plate. The flywheel is bolted directly to the engine crankshaft and rotates when the crankshaft turns. The pressure plate is bolted to the flywheel. The result is that both flywheel and pressure plate rotate together.
主动部分由飞轮和压盘两部件组成。飞轮用螺栓直接 连接到发动机曲轴上，随曲轴旋转而旋转。压盘与飞 轮连接，这样飞轮和压盘一起旋转。
The driven member（从动部分） The driven member, or clutch disc, is located between the flywheel and pressure plate. The disc has a splined hub that locks to the splined input shaft on the gearbox. Any rotation of the clutch disc turns the input shaft. Likewise, any motion of the input shaft moves the clutch disc. The splines allow the clutch disc to move forward and backward on the shaft as it engages and disengages. 从动盘毂
摩擦片
从动盘本体
减振器盘 摩擦 片
The inner part of the clutch disc, called the hub flange, has a number of small coil springs. These springs are called torsional springs. They let the middle part of the clutch disc turn slightly on the hub. Thus, the springs absorb the torsional vibrations of the crankshaft. When the springs have compressed completely, the clutch moves back until the springs relax. In other words, the clutch absorbs these engine vibrations, preventing the vibrations from going through the drive train. 从动盘的内部（毂缘）有一些叫作扭转弹簧的 小螺旋弹簧，这些弹簧使得从动盘中部相对从 动盘毂能有轻微转动，从而吸收曲轴的扭转振 动。压紧弹簧完全压缩时，离合器回位直到弹 簧开始松弛。也就是说，离合器吸收发动机的 振动，防止振动传递给传动系。
The hydrodynamic coupling(液力偶合器)
Most automatic transmissions use a hydrodynamic coupling to join the engine crankshaft to the transmission input shaft. Hydrodynamic couplings and hydrodynamic torque converters transfer the torque through fluid-flow forces. They provide advantages when driving away thanks to infinitely variable conversion of speed and torque, with the maximum torque being available at the drive-away point (engine turning, vehicle stationary).
大部分自动变速器采用液力耦合器连接发动机曲轴和变速器 输入轴。液力耦合器和液力变矩器通过流动的液体的能量传 递力矩。由于转速和力矩的转变是连续变化的，它们的优点 是在起步时得到最大力矩。
A fluid coupling is a two element drive that is incapable of multiplying torque, while a torque converter has at least one extra element - the stator- which alters the drive's characteristics during periods of high slippage, producing an increase in output torque. In a torque converter there are at least three rotating elements: the pump, which is mechanically driven by the prime mover; the turbine, which drives the load; and the stator, which is interposed between the pump and turbine so that it can alter oil flow returning from the turbine to the pump. The classic torque converter design dictates that the stator should be prevented from rotating under any condition. In practice, however, the stator is mounted on an overrunning (freewheel) clutch, which prevents the stator from counter-rotating with respect to the prime mover but allows forward rotation.
place or insert between one thing and another 泵轮 导轮 涡轮
3.3 Transmission
?Powerplant：动力装置 ?Manual Transmission ?Automatic Transmission ?Gear：
–齿轮 –a particular function or state of adjustment of engaged gears （调）挡 –动词 调档，调速
?Multiply：乘
–increase or cause to increase greatly in number or quantity
1）Sliding-mesh
3）Synchro-mesh
2）Constant-mesh
Although this type is rarely used today, it is included because the gear layout forms the basic construction of most modern manual transmissions. The spur gears are mounted on four shafts: primary shaft (input shaft), layshaft (countershaft), mainshaft and reverse idler shaft.
输入轴 中间轴 主轴 怠速轴
Neutral：中立人士、空挡位置 top gear 空挡 neutral gear
In the case of a sliding-mesh gearbox, gear changing demands skill if noise is to be avoided. Crashing (or clashing) of the gears as the result of a bad change suggests the reason why this type is often called a 'crash' type gearbox. The operation double declutching must be performed by the driver if a quick and quiet change is required. This operation equalizes the peripheral (outside) speeds of the gears to be meshed
对滑动啮合变速器来说，换挡时要避免噪声是需要技巧的。齿轮打齿 是由换挡不当引起的，这也是滑动啮合变速器经常被称为“碰撞”型变 速器的原因。 为实现快速、安静地换挡，驾驶员必须使用双脚离合器。这个动作补 偿了即将啮合的齿轮圆周速度。
Fig. 3.6 illustrate the flow of torque through a typical constant-mesh transmission.This type uses helical or double helical gears which are always in mesh. The mainshaft gear wheels are mounted on bearings and when a gear is required the mainshaft gear is locked to the shaft by a dog clutch.
斜齿轮、人字形齿轮， 牙嵌式离合器
Synchro-mesh transmission 同步式变速器
As the name suggests this type has a synchronization device which equalizes the speeds of the two members that have to be meshed to obtain the gear. The layout is similar to the constant-mesh but has friction cones fitted between the dog clutch and the gear wheel.
顾名思义，同步啮合变速器带有同步装置，使得换挡时 要啮合的两齿轮转速达到相同。同步啮合变速器的结构 与常啮合变速器类似，不同之处是在接合套和齿轮之间 有摩擦锥面。