ESP 汽车英语 中英对照 Unit4 passageA 高等教育出版社

发动机在其制动扭功率曲线上的给定的转速点发出一定量的扭矩。 在低速时，扭矩较低。随着发动机速度的增高，扭矩也在增加， 而且当达到峰值后它将开始逐渐变小（达到最高速度之前）。


A three-speed standard synchromesh transmission is designed to develop great torque in fow gear in order to accelerate a vehicle quickly. However, the fow gear top speed is low. When the transmission is shift into second gear, greater speed and less torque are produced. In the third gear (direct drive), refatively fittle torque is produced at low speeds, but maximum engine speed is obtainable. synchromesh 同步啮合 标准的带同步器的三速速箱被设用来在低档时提高转矩来尽快的 加速车辆。然而，低档时最高转速较低。当变速箱被换为二档时 可以得到较高的转速和较低的扭矩。在三档（直接传动）时，在 低转速得到相对较小的扭矩，但是可以获得发动机的最大转速。
Automobile Drive Line
The Drive Line


An automobile drive line is designed to transfer torque from an engine to an set of drive wheels. The usual system includes a coupling that joins the engine to the drive system, a transmission, a driveshaft, a geared differential, universal joints that connect the driveshaft to the transmission and differential, and two axles that drive the rear wheels. rear 后面的，后方的 汽车传动系的设计是用来把发动机产生的转矩传送到驱动车轮。通常这套 系统包括一个用来连接发动机和驱动系统的装置，变述箱，传动轴，齿轮 差速器把传动轴连接到变速箱和差速器的万向节和两根用来驱动后轮的半 轴。


The transmission is used to vary the ratio of crankshaft turns to driveshaft turns in order to obtain satisfactory power, acceleration, and fuel economy under alf conditions of load. It also makes it possible to reverse the direction of rotation of the driveshaft so that the vehicle can be driven in reverse.




The driveshaft connects the transmission to the differential, and the differential drives the rear axles. The differential provides a fixed ratio of driveshaft turns to rear axfe turns. Thus, it has much to do with the performance, and operating economy of a vehicle. Fixed 固定的 传动轴连接变速器与差速器，差速器驱动后轴转动。差速器提供 一个固定的传动轴与驱动轴之间的传动比。因此，它与车辆的性 能和操作经济性大有关系。 A few automobiles - both American and foreign – are equipped with front wheel drive systems. 一些汽车（美国及美国以外的）装备前轮驱动系统。


Friction clutches couple engines to standard transmissions, and fluid couplings -- nearfy always the torque converter type - are used with automatic units. 摩擦式离合器联结发动机与手（标准配置）变速器，液力耦台器 （但多数是液力变矩器）则用于自动变速器。
Transmissions

An engine develops a specific amount of torque at a given rpm point on its torque-brake horsepower curve. At low speeds, the torque is low. As the speed of the engine increases, the torque also increases, and it reaches a peak and begins to taper off before the maximum speed is reached. peak 顶点，最高峰，最高的
Gears



Spur, helical, and hypoid gears and planetary gear sets are useed in automobile drive lines. Each type of gear has advantages and limitations. As a rule, hypoid gears are used in differentials, and the other types are used in transmissions. Helical 螺旋状的；hypoid 准双曲面齿轮的； planetary 行星的 正齿轮，螺线齿轮，准双曲面齿轮和行星齿轮组被用于汽车传动 系。每种类型的齿轮各有其优越性和局限性。一般来说，螺线齿 轮用于差速器，而其他类型的齿轮用于变速筘。



Whenever the power output of a gear train is increased, the top speed is decreased. The reverse is also true. For example, the increased power output in the first gear range of a standard transmission results in a much lower top output shaft speed than is the case in the third gear range. 当变速器的输出转矩增加，最高速度就会下降。倒档也是同样。 举例来说，在标准变速箱的一档转矩输出的增加造成它的最高转 速要比三档低
vary 改变；变化 ratio 比率


变速器是用来改变曲轴与传动轴之间的传动比以便在任何载荷 的情况下都能获得令人满意的功率，加速度及燃油经济性。'它 同样也使政变传动轴的转向成为可能，从而使汽车可以实现倒
行。

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Both manually operated (standard) transmissions and automatic transmissions are currently in use. Three-speed and four-speed standard transmissions are available, as are two-speed and three-speed automatic transmtssions. manually 手动的 手动（标准配置）变速器和自动变速器当前都有使用。不仅可选用3 速和4速标准手动变速器，而且也可选用2速和3速自动变速器。
The Clutch

A friction clutch is used to connect an engine to, and disconnect it from, a standard transmission so that the gears in the transmission can be shifted easily without clashing. Slippage in the clutch permits smooth operation when it is engaged or


Gear ratio. In a specific transmission gear range, the torque of an automobile driveshaft and speed of the automobile depend on the torque and speed of the engine and on the gear ratios of the transmission and differential. The principles of speed and torque are well illustrated by the design of a gearset. For example, if a larger gear having a radius of 6 inches is meshed with a smaller gear of a 3-inch radius, the gear ratio is two to one (2:1). Since the larger gear has the same number of teeth per inch of gear circumference, it has twice as many teeth as the smaller gear. Therefore, the gear ratio of a pair of gears can be found by measuring the radius of each gear or by counting the number of teeth on each gear. gearset 齿轮组；radius 半径；meshed 啮和； circumference 圆周，周围 齿轮传动比，在限'定的变速箱齿轮范围，汽车传动轴的扭矩和汽车 的速度依赖于发动机的扭矩和转速以及变速籀和差速器的齿轮传动 比。速度和扭矩原理可以很好地以齿轮组的设计说明。举例来说如 果一个较大的6英寸半径的齿轮与一个较小的3英寸半径的齿轮一起 啮合，那么齿轮传动比是二比一（2:1）。较大的齿轮在圆周上每 一寸都具有相同齿数，但两倍于较小齿轮的齿数。因此，一对齿轮 的传动比可以由测量每个齿轮的半径或计算每个齿轮上的齿数来确 定。