Unit 1Automobile Basics 1.1Introduction The word automobile literally means self-moving. It is derived from the Greek word autos, which means self,and the French world mobile, which means moving. An automobile is a wheeled motor or vehicle used for transporting passengers and cargoes and designed to run primarily on roads. Automobile is fine pieces of precision engineering, technology and design, with 15,000 individual parts and working units each. Fig. 1.1Basic car components Along with the development of science and technology, many engineering improvements have been done. However, the basic principles have remained the same since the advent of automobile in the 1870s. It has an internal-combustion engine, four rubber wheels and a protective body. To provide the energy required to make the car move, the engine needs either petrol or diesel, air, and electric current.The engine temperature is usually kept relatively low by water or air. The major moving parts of the engine are the pistons.They move up and down very quickly inside cylinders. To reduce engine wear and prevent seizure the pistons are lubricated by oil. The clutch connects the engine to the gearbox by means of plates and the drive shafts are arranged to suit whether the car is front-or rear-wheel drive. 1.2Automotive History Automobile as we know it was not invented in a single day by a single inventor. The history of automobile reflects an evolution that took place worldwide. It is estimated that over 100,000 patents created the modern automobile. Starting in the late 1700s, European engineers began tinkering with motor-powered vehicles. Steam, combustion, and electrical motors had all been attempted by the mid 1800s. Automotive production on a commercial scale started in France in 1890. Commercial production began at the beginning of the 1900s in the United States. In those days, the European industry consisted of small independent firms that would turn out a few cars by means of precise engineering and handicraft methods. The American automobile plants were assembly line operations, which meant using parts made by independent suppliers and putting them together at the plants. At the beginning of the century the automobile entered the transportation market as a toy for the rich.Along with the demand for travel freely for the general population, automobile became cheaper and more accessible to the middle class. Henry Ford freed common people. The automobile created mobility on a scale never known before, and the total effect on living habits and social customs is endless. The convenience of the automobile freed people from the need to live near rail lines or stations; they could choose locations almost anywhere in an urban area, as long as roads were available to connect them to other places. 1.3Principal Components Todays average car contains more than 15,000 separate, individual parts that must work together. Fig. 1.2 shows the major systems of a vehicle. These parts can grouped into the following major categories: Fig. 1.2General location of the major vehicle systems  Body and frame — support and enclose the vehicle  Engine — provides dependable, efficient power for the vehicle  Computer systems — monitor and control various vehicle systems  Fuel system — provides a combustible air-fuel mixture to power the engine  Power-Supply system — generates and/or distributes the power needed to operate the vehicles electrical and electronic components  Cooling and lubrication systems — prevent engine damage and wear by regulating engine operating temperature and reducing friction between internal engine parts  Exhaust and emission control systems — quiet engine noise and reduce toxic substances emitted by the vehicle  Drive train systems — transfer power from the engine to the drive wheels  Suspension, steering, and brake systems — support and control the vehicle  Accessory and safety systems — increase occupant comfort, safety and convenience 1.3.1Frame, Body and Chassis The body and frame are the two largest sections of a motor vehicle.The frame is the strong metal structure that provides a mounting place for the other parts of the vehicle. The frame holds the engine, transmission, suspension, and other assemblies in position. An automobile body is a sheet metal shell with windows, doors, a hood, and a trunk deck built into it. It provides a protective covering for the engine, passengers and cargo. The body is designed to keep passengers safe and comfortable. The body styling provides an attractive, colorful, modern appearance for the vehicle. The term chassis is often used when referring to a vehicles frame and everything mounted to it except the body-tires, wheels, engine, transmission, drive axle assembly, and frame. 1.3.2Engines The engine acts as the power unit, which is designed to convert energy into useful mechanical motion. The internal-combustion engine (ICE) is widely used in modern automobile. The internal-combustion engine is a device used to convert the chemical energy of the fuel into heat energy, and then to convert this heat energy into usable mechanical energy. The working process includes four strokes, which are intake stroke, compression stroke, power stroke and exhaust stroke. In practical work, the reciprocating movement of piston in the cylinder is converted to rotary motion of the crankshaft. The internal-combustion engines can be divided into two types: gasoline (spark-ignition engine) and diesel (compression-ignition engine). Fig. 1.3Body over frame construction Fig. 1.4Major parts on an automotive engine 1.3.3Computer System The computer system uses electronic and electrical devices to monitor and control various systems in the vehicle, including the fuel, ignition, drive train, safety and security systems. The use of computer systems has improved vehicle efficiency and dependability. Three major parts are included in computer system: sensors, control module and actuators. 1.3.4Fuel System The fuel system must provide the correct mixture of air and fuel for efficient combustion. This system must add the right amount of fuel to the air entering the cylinders, alter the air-fuel ratio with changes in operating conditions. There are three basic types of automotive fuel systems: gasoline injection system, diesel injection system and carburetor systems. Fig. 1.5Major parts on an automotive engine 1.3.5Electrical System The vehicles electrical system consists of several subsystems (smaller circuits): ignition system, starting system, charging system and lighting system. Each sub-system is designed to perform a specific function, such as fire the spark plugs to ignite the engines fuel mixture, rotate the crankshaft to start the engine, illuminate the highway for safe night driving,etc.  An ignition system is needed on gasoline engines to ignite the air-fuel mixture. It produces an extremely high voltage to operate the spark plugs, which can fire air-fuel mixture at the correct time, thus to produce power.  The starting system has a powerful electric starting motor that rotates the engine crankshaft until the engine fires and runs on its own power.  The charging system is needed to replace electrical energy drawn from the battery during starting systems operation. To re-energize the battery, the charging system forces electric current back into the battery.  The lighting system consists of the components that operate a vehicles interior and exterior lights (fuses, wires, switches, relays, etc). 1.3.6Cooling and Lubrication Systems The cooling and lubrication systems are designed to prevent engine damage and wear. The cooling system maintains a constant engine operating temperature. It removes excess combustion heat to prevent engine damage and also speeds engine warm-up. The lubrication system reduces friction and wear between internal engine parts by circulating filtered engine oil to high-friction points in the engine. It also helps cool the engine by carrying heat away from internal engine parts. 1.3.7Exhaust and Emission Control Systems The exhaust system quiets the noise produced during engine operation and routes engine exhaust gases to the rear of the vehicle body. Fig. 1.6Exhaust system An automobile exhaust system comprises of various devices or parts of an automotive engine, which are used for discharging burned gases or steam. Exhaust system consists of tubing, which is usually used for emitting out waste exhaust gases with the help of a controlled combustion taking place inside an automobile engine. All the burnt gases are exhaled from an engine using one or more exhaust pipes. These gases are expelled out through several devices like cylinder head, exhaust manifold, turbocharger, catalytic converter, muffler and silencer. The emission control systems are used to reduce the amount of toxic (poisonous) substances produced by an engine. Some systems prevent fuel vapors from entering the atmosphere (air surrounding the earth). Other emission control systems remove unburned and partially burned fuel from the engine exhaust. 1.3.8Drive Train System The drive train transfers turning force from the engine crankshaft to the drive wheels. The drive train parts commonly found on a front-engine, rear-wheel-drive vehicle include the clutch, transmission, drive shaft, and rear axle assembly. The drive train parts used on most front-engine, front-wheel-drive vehicles include the clutch, transaxle, and drive axles. Fig. 1.7Drive train components for front-drive (left) and rear-drive (right) 1.3.9Suspension, Steering and Brake Systems The suspension, steering, and brake systems are the movable parts of the chassis. The suspension system allows the vehicles wheels and tires to move up and down with little effect on body movement. This makes the vehicles ride smooth and safe. The suspension system also prevents excessive body lean when turning corners quickly. The steering system allows the driver to control vehicle direction by turning the wheels right or left. It uses a series of gears, joints and rods to do this. The brake system produces friction to slow or stop the vehicle. When the driver presses the brake pedal, fluid pressure actuates a brake mechanism at each wheel. These mechanisms force friction material (brake pads or shoes) against metal discs or drums to slow wheel rotation. New Words automobile汽车 petrol车用汽油 diesel柴油 piston活塞 lubricate润滑 gearbox变速箱 body车身 frame车架 fuelsystem燃油系统 air-fuel mixture油气混合物 electrical system电气系统 cooling system冷却系统 lubrication system润滑系统 exhaust system排气系统 emission control system排放控制系统 drive train system传动系统 suspension悬架 steering转向 brake刹车 accessory附属的 safety system安全系统 transmission变速器 hood发动机罩 trunk deck后备箱盖，行李箱门 chassis底盘 drive axle assembly启动桥总成 internal-combustion engine内燃机 crankshaft曲轴 carburetor汽化器，化油器 spark plug火花塞 ignition system点火系统 starting system启动系统 charging system充电系统 lighting system灯光系统 transaxle变速驱动桥 clutch离合器 driveshaft传动轴 Translations 1. An automobile body is a sheet metal shell with windows, doors, a hood, and a trunk deck built into it. It provides a protective covering for the engine, passengers and cargo. 译： 汽车车身是一种将车窗、车门、发动机罩和后备箱盖包括在内的钣金壳体。车身为发动机、乘员和货物提供保护性遮盖。 2. The internal-combustion engine is a device used to convert the chemical energy of the fuel into heat energy, and then to convert this heat energy into usable mechanical energy. 译： 内燃机是用于将燃料的化学能转化为热能，再将热能转化为可用机械能的装置。 3. It removes excess combustion heat to prevent engine damage and also speeds engine warm-up. 译： 它（冷却系统）将过量的燃烧热量移除，可以防发动机受损，并使发动机预热加快。 4. The lubrication system reduces friction and wear between internal engine parts by circulating filtered engine oil to high-friction points in the engine. 译： 润滑系统通过将滤过的发动机油循环至发动机等摩尖头部件，降低发动机内部零件之间的摩擦和磨损。 5. The exhaust system quiets the noise produced during engine operation and routes engine exhaust gases to the rear of the vehicle body. 译： 排气系统将发动机工作期间产生的排气噪声降低，同时将发动机废气引至车身后部排出。 6. The drive train transfers turning force from the engine crankshaft to the drive wheels. 译： 传动系将发动机曲轴的旋转力传送到驱动轮上。 Exercises 1. Please answer the following two questions. 1) Identify and locate the most important parts of a vehicle. 2) Describe the purposes of the fundamental automotive systems. 2. Translate the following sentences into Chinese. 1) By definition an automobile or car is a wheeled vehicle that carries its own motor and transports passengers. The automobile as we know it was not invented in a single day by a single inventor. The history of the automobile reflects an evolution that took place worldwide. 2) It is estimated that over 100,000 patents created the modern automobile. You can point to the many firsts that occurred along the way to producing the modern car; and with that goal in mind, highlighted below are articles, biographies, timelines, and photo galleries related to the history of the automobile and its many inventors. 3) A multi-part feature of the history of automobiles starts with the first steam, electrical, and gasoline-engine cars. Learn the controversy behind what was the first car in history and the importance of the internal-combustion engine. The lives of many famous automotive makers are explored in detail with special pages on the assembly line, the origins of the name automobiles, the patent disputes, and more. 4) The term motorcar has also been used in the context of electrified rail systems to denote a car which functions as a small locomotive but also provides space for passengers and baggage. These locomotive cars were often used on suburban routes by both interurban and intercity railroad systems. 5) There are approximately 600 million passenger cars worldwide (roughly one car per eleven people). Around the world, there were about 806 million cars and light trucks on the road in 2007; the engines of these burn over a billion cubic meters (260 billion US gallons) of petrol/gasoline and diesel fuel yearly. The numbers are increasing rapidly, especially in China and India. Reading Material Automobile Propulsion Systems Reciprocating Internal-combustion Engines The modern automobile is usually driven by a water-cooled, piston-type internal-combustion engine, mounted in the front of the vehicle; its power may be transmitted either to the front wheels, to the rear wheels, or to all four wheels. Some automobiles use air-cooled engines, but these are generally less efficient than the liquid-cooled type. In some models the engine is carried just forward of the rear wheels; this arrangement, while wasteful of space, has the advantage of better weight distribution. Although passenger vehicles are usually gasoline fueled, diesel engines (which burn a heavier petroleum oil) are employed both for heavy vehicles, such as trucks and buses, and for a small number of family sedans. Both diesel and gasoline engines generally employ a four-stroke cycle. The Wankel Engine For some years, it was hoped that the Wankel engine, a rotary internal-combustion engine developed by Felix Wankel of Germany in 1954, might provide an alternative to the reciprocating internal-combustion engine because of its low exhaust emissions and feasibility for mass production. In this engine a three-sided rotor revolves within an epithrochoidal drum (combustion chamber) in which the free space contracts or expands as the rotor turns. Fuel is inhaled, compressed, and fired by the ignition system. The expanding gas turns the rotor and the spent gas is expelled. The Wankel engine has no valves, pistons, connecting rods, reciprocating parts, or crankshaft. It develops a high horsepower per cubic inch and per pound of engine weight, and it is essentially vibrationless, but its fuel consumption is higher than that of the conventional piston engine.