combustion gases with the chamber. The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power.
Section B Chassis
Task 1 Before reading the passage, please try to complete the following tasks.
1. Do you know the entire structure of automobiles chassis? Please research online for the information about chassis of automobiles and try to understand it?s function.
2. Please research online for components of an automobile chassis and state them in English according to the following picture.
Reading B
Main Components of Automotive Chassis
Chassis is considered as a support frame for an auto body. It supports the driving, steering, braking and suspension system. The chassis forms the main structure of a modern automobile. A large number of designs in a pressed-steel frame form a skeleton on which the engine, wheels, axle assemblies, transmission, steering mechanism, brakes and suspension members are mounted. During the manufacturing process the body is flexibly bolted to the chassis. A vehicle’s chassis system is a determining factor when it comes to handling characteristics, influencing vehicle driving dynamics, comfort, safety, and road holding ability.
The following sections describe some key components of the chassis and how they work.
Transmission System
The transmission, also known as the gearbox, transfers power from the engine to the drive shaft. As the engine’s crankshaft rotates,
combinations of transmission gears pass the energy along to a drive shaft. The drive shaft causes axles to rotate and turn the wheels. By using gears of different sizes, a transmission alters the rotational speed and torque of the engine passed along to the drive shaft. High-speed gears permit the car to travel faster, while low-speed gears provide more power for starting a car from a standstill and for climbing hills.
The transmission usually is located just behind the engine, although some automobiles are designed with a transmission mounted on the rear axle. There are three basic transmission types: manual, automatic and continuously variable.
Braking System
Brakes enable the driver to slow or stop the moving vehicle. An anti-lock braking system (ABS) uses a computer, sensors, and a hydraulic pump to stop the automobile’s forward motion without locking the wheels and putting the vehicle into a skid. Introduced in the 1980s, ABS helps the driver maintain better control over the car during emergency stops and while braking on slippery surfaces.
Automobiles are also equipped with a hand-operated brake used for emergencies and to securely park the car, especially on uneven terrain。 Pulling on a lever or pushing down on a foot pedal sets the brake.
Steering System
Automobiles are steered by turning the front wheels, although a few automobile types have all-wheel steering. Most steering systems link the front wheels together by means of a tie-rod. The tie-rod insures that the turning of one wheel is matched by a corresponding turn in the other.
When a driver turns the steering wheel, the mechanical action rotates a steering shaft inside the steering column. Depending on the steering mechanism, gears or other devices convert the rotating motion of the steering wheel into a horizontal force that turns the wheels.
Suspension System
The suspension system, part of the undercarriage of an automobile, contains springs that move up and down to absorb bumps and vibrations. In one type of suspension system, a long tube, or strut, has a shock
absorber built into its center section. Shock absorbers control, or dampen, the sudden loading and unloading of suspension springs to reduce wheel bounce and the shock transferred from the road wheels to the body. One shock absorber is installed at each wheel. Modern shock absorbers have a telescoping design and use oil, gas, air or a combination to absorb energy.
Active suspensions are computer-controlled adjustments of the downward force of each wheel as the vehicle corners or rides over uneven terrain. Sensors, a pump and hydraulic cylinders are all monitored and controlled by a computer, enable the vehicle to lean into corners and compensate for the dips and dives that accompany emergency stops and rapid acceleration.
Wheels and Tyres
Wheels support the vehicle’s weight and transfer torque to the tyres from the drivetrain and braking systems. Automobile wheels are generally made of steel or aluminum. Aluminum wheels are lighter, more impact absorbent, but more expensive.
Tyres help smooth out the ride and provide the automobil’s only contact with the road, so traction and strength are primary requirements. Tyre treads come in several varieties to match driving conditions.
New Words steer [sti?] vt. & vi. 1.驾驶, 掌舵
2.操纵；控制；引导
suspension [s?'spen??n] n. 1.暂停，中止
2.悬架，悬置机构 3.悬，挂，吊
skeleton ['skelitn] n. 1.（建筑物等的）骨架，框架
2. 梗概；提纲；轮廓
axle ['?ks?l, '?ksl] n. 轮轴，车轴
assembly [?'sembli] n. 装配，组装，总成
transmission [tr?nz'mi??n] n. 1.传送，传播，传达 2.传动装置，变速器
mechanism ['mek?niz?m] n. 1.机械装置
2.机械；机械部分
mount [maunt] vi. 增加；上升
vt. 镶嵌；安置
manufacture ['m?nju'f?kt??] vt. 1.(大规模)制造；生产
2.加工，把……制成用品 n. 1.(大规模)制造；加工 2.制造品，产品
flexible ['fleks?bl] adj. 1.易弯曲的，柔韧的
2.灵活的，可变通的
bolt [b?ult] n. 1.螺栓
2.(门或窗)插销，闩 vt. 用螺栓固定
dynamic [dai'n?mik] n. 1.力学；动力学
2. 动力
component [k?m'p?un?nt] n. 成分，组成部分，部件，元件 gearbox ['ɡi?b?ks] n. 变速箱，变速器 transfer [tr?ns'f?:] vt. & vi. 转移；迁移 shaft [?ɑ:ft] n. 1.箭杆，矛柄
2.轴
crankshaft ['kr??k?ɑ:ft] n. 机轴
rotate [r?u'teit] vt. & vi. (使某物)旋转[转动],
gear [ɡi?] n. 齿轮
alter ['?:lt?] vt. & vi. 改变，更改
rotational [r?u'tei??n?l] adj. 转动的，轮流的
torque [t?:k] n. (尤指机器的)扭转力；转(力)矩 standstill ['st?nd'stil] n. 静止状态；停顿 rear [ri?] adj. 后面的；后部的
variable ['v??ri?bl，'ve?ri?bl] adj. 1.变化的，可变的，易变的
2.可更改的；可变的 hydraulic [ha?'dr?:l?k] adj. 液力的，液压的，水力学的 pump [p?mp] n. 泵，打气筒，抽水机