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TECHNICAL ENGLISH for AUTOMOTIVE ENGINEERING. (FIRST EDITION) Edited by: Nguyen Tuan Hung, MEng. Mechanical Engineering Faculty Ho Chi Minh City University of Industry Ministry of Industry. Ho Chi Minh City, September-2007 AUTOMOTIVE INTRODUCTION. 1 Technical English for AUTOMOTIVE ENGINEERING. 1 Chapter 1: Automotive Introduction. I. PRE-READING QUESTION: 1. What are the main functions of automobile nowadays? 2. How automobile can be classified? 3. How many major systems in automobile? II. READING Part a: Automobile Introduction Automobile, self-propelled vehicle used primarily on public roads but adaptable to other surfaces. Automobiles changed the world during the 20th century. From the growth of suburbs to the development of elaborate road and highway systems, the so-called horseless carriage has forever altered the modern landscape. The manufacture, sale, and servicing of automobiles have become key elements of industrial economies. But along with greater mobility and job creation, the automobile has brought noise and air pollution, and automobile accidents rank among the leading causes of death and injury throughout the world. But for better or worse, the 1900s can be called the Age of the Automobile, and cars will no doubt continue to shape our culture and economy well into the 21 st century. Automobiles are classified by size, style, number of doors, and intended use. The typical automobile, also called a car, auto, motorcar, and passenger car, has four wheels and can carry up to six people, including a driver. Larger vehicles designed to carry more passengers are called vans, minivans, omnibuses, or buses. Those used to carry cargo are called pickups or trucks, depending on their size and design. Minivans are van-style vehicles built on a passenger car frame that can usually carry up to eight passengers. Sport-utility vehicles, also known as SUVs, are more rugged than passenger cars and are designed for driving in mud or snow. The automobile is built around an engine. Various systems supply the engine with fuel, cool it during operation, lubricate its moving parts, and remove exhaust gases it creates. The engine produces mechanical power that is transmitted to the automobile’s wheels through a drivetrain, which includes a transmission, one or more driveshafts, a differential gear, and axles. Suspension systems, which include springs and shock absorbers, cushion the ride and help protect the vehicle from being damaged by bumps, heavy loads, and other stresses. Fig1.1: The drive-train. AUTOMOTIVE INTRODUCTION. 1 Technical English for AUTOMOTIVE ENGINEERING. 2 Wheels and tires support the vehicle on the roadway and, when rotated by powered axles, propel the vehicle forward or backward. Steering and braking systems provide control over direction and speed. An electrical system starts and operates the engine, monitors and controls many aspects of the vehicle’s operation, and powers such components as headlights and radios. Safety features such as bumpers, air bags, and seat belts help protect occupants in an accident. Fig 1.3: Four-bar twist beam axle by Renault, with 2 torsion bar springs both for the left and right axle sides. Fig 1.2: A multi-link rear axle, – a type of suspension system which is progressively replacing the semi-trailing arm axle, and consists of at least one trailing arm on each side. Fig 1.4: Steering and suspension system. AUTOMOTIVE INTRODUCTION. 1 Technical English for AUTOMOTIVE ENGINEERING. 3 Part b: Automobile Physical Configuration Fig 1.5: Automobile systems The automobile configuration is depicted in Figure 1.5, in which many of the important automotive systems are illustrated. These systems include the following: 1. Engine 2. Drivetrain (transmission, differential, axle) 3. Suspension 4. Steering 5. Brakes 6. Instrumentation 7. Electrical/electronic 8. Motion control 9. Comfort/convenience 10.Entertainment/communication/navigati on. III. NEW WORDS Look up for the new words Automobile (n) Rank (n) Truck (n) Driveshafts (n) Self-propelled vehicle (n) Doubt (n, v) Carriage (n) Differential (n) Suspension systems (n) Shape (v, n) Rugged (a) Gear (n) Steering system (n) Classify (v) Mud (n) Axles (n) Sport-utility vehicles (n) Van (n) Snow (n) So-called (a) braking system (n) Omnibuses (n) Wheel (n) Springs (n) For better or worse (exp) Pickup (n) Drive-train (n) shock absorbers (n) Element (n) Landscape (n) Transmission (n) cushion (n) Elaborate (a) bumps (n) electrical system (n) headlight (n) Suburbs (n) bumper (n) occupant (n) adaptable to (a) Highway (n) Primary (a) IV. COMPREHENSION QUESTION Answer these questions: 1. Why do we call automobiles as self-propelled vehicles? AUTOMOTIVE INTRODUCTION. 1 Technical English for AUTOMOTIVE ENGINEERING. 4 2. What are the key elements of industrial economies? 3. What are advantages of automobile in our life? 4. What are disadvantages of automobile in our life? 5. What are the main functions of the engine? 6. What are the main functions of Suspension systems? 7. What are the main functions of wheels and tires? 8. What are the main functions steering and braking systems? 9. What are the main functions of electrical system? 10. What component(s) makes automobiles safer? V. TRUE/FALSE Decide if these statements are True or False: 1. Automobiles can be use primarily on public roads. ( True  False) 2. Servicing of automobiles has become key elements of industrial economies.( True  False) 3. Automobile industries create only mobilities and jobs. ( True  False) 4. The 21 st century can be called the Age of the Automobile. ( True  False) 5. Vans are designed to carry people. ( True  False) 6. Minivans can carry more than 9 people. ( True  False) 7. Sport-utility vehicles are more rugged than passenger cars. ( True  False) 8. Sport-utility vehicle can be drived in mud or snow. ( True  False) AUTOMOTIVE INTRODUCTION. 1 Technical English for AUTOMOTIVE ENGINEERING. 5 9. The engine produces mechanical power. ( True  False) 10. Drivetrain consist of a transmission, one or more driveshafts, a differential gear, and axles. ( True  False) 11. Suspension systems includes springs and shock absorbers and cushion. ( True  False) 12. Wheels and tires are rotated by powered axles. ( True  False) 13. Steering and braking systems provide control over direction and speed. ( True  False) 14. Electrical system only starts and operates the engine. ( True  False) 15. Bumpers, air bags, and seat belts are safety features of automobile. ( True  False) VI. WORD(S) SELECTIONS Select ONE word(s) in the below box and fill in the gap in column B with its meaning word in column A a. The system protects vehicles from bumps, loads, and stresses c. Cars designed for driving in mud or snow. e. Self- propelled vehicle. g. The system locates car’s position. i. Vehicles used to carry cargo b. Capable of d. The system transmit engine’s power to the wheels f. The system controls car’s direction. h. Double- deck bus j. The system cools the engine during its operation. No Column A Column B No Column A Column B 1 Automobile 6 Sport-utility vehicles 2 Pickups 7 Omnibus 3 Adaptable to 8 Drivetrain system 4 Steering system 9 Navigation system 5 Suspension system 10 Coolant system THE ENGINE 2 Technical English for AUTOMOTIVE ENGINEERING. 6 Chapter 2: The Engine I. PRE-READING QUESTION 1. Name some kinds of engines you know. 2. Do you have a four-stroke engine in your house? How powerful is it? 3. What type of fuel does a four-stroke engine run on? II. READING 1. The reciprocating engine The engine is the heart of a car although it is normally hidden under the bonnet. The engine is exposed in a motorcycle but the detailed mechanisms are not visible. There are two main types of reciprocating engine, the four-stroke and the two-stroke engine: 1.1. The petrol engine 1.1.1. Four-stroke engine Fig2.2: Basic operations of four-stroke cycle engine. Fig 2.1: Cutaway of four- stroke cycle petrol engine (courtesy of Volvo Car Corporation). THE ENGINE 2 Technical English for AUTOMOTIVE ENGINEERING. 7 The four-stroke engine is also referred to as the Otto cycle engine after its inventor N.A. Otto. Most cars use the four-stroke engine. An individual cycle comprises four strokes: 1, intake stroke; 2, compression stroke; 3, power stroke and 4, exhaust stroke. These four strokes repeat to generate the crankshaft revolution. + Intake stroke: the intake stroke draws air and fuel into the combustion chamber. The piston descends in the cylinder bore to evacuate the combustion chamber. When the inlet valve opens, atmospheric pressure forces the air-fuel charge into the evacuated chamber. As a result, the combustible mixture of fuel and air fills the chamber. + Compression stroke: at the end of the intake stroke, both inlet and exhaust valves are closed. The inertial action of the crankshaft in turn lifts the piston which compresses the mixture. The ratio of the combustion chamber volume before and after compression is called the compression ratio. + Power stroke: when the piston ascends and reaches top dead center, an electric current ignites the spark plug and as the mixed gas burns, it expands and builds pressure in the combustion chamber. The resulting pressure pushes the piston down with several tons of force. + Exhaust stroke: during the exhaust stroke, the inlet valve remains closed whilst the exhaust valve opens. The moving piston pushes the burned fumes through the now open exhaust port and another intake stroke starts again. During one cycle, the piston makes two round trips and the crankshaft revolves twice. The inlet and exhaust valves open and close only once. The ignition plug also sparks only once. A petrol engine, whether four- or two-stroke, is called a Spark Ignition (SI) engine because it fires with an ignition plug. The four-stroke-cycle engine contains the lubricating oil in the crankcase. The oil both lubricates the crankshaft bearings and cools the hot piston. 1.1.2. The two-stroke engine The two-stroke engine is similar to that of the four-stroke-cycle engine in its reciprocating mechanism. It uses the piston-crankshaft mechanism, but requires only one revolution of the crankshaft for a complete power-producing cycle. The two-stroke engine does not use inlet and exhaust valves. The gas exchange is implemented by scavenging and exhaust port-hole openings in the bore wall. The upward and downward motion of the piston simultaneously opens and closes these port-holes. The air-fuel mixture then goes in or out of the combustion chamber through the port-holes. Combustion takes place at every rotation of the crankshaft. In the two-stroke engine, the space in the crankcase works as a pre-compression chamber for each successive fuel charge. The fuel and lubricating oil are premixed and introduced into the crankcase, so that the crankcase cannot be used for storing the lubricating oil. When combustion occurs in the cylinder, the combustion pressure compresses the new gas in the crankcase for the next combustion. The burnt gas then exhausts while drawing in new gas. The lubricating oil mixed into the air-fuel mixture also burns. Since the two-stroke engine does not use a valve system, its mechanism is very simple. The power output is fairly high because it achieves one power stroke per two revolutions of the crankshaft. However, although the power output is high, it is used only for small motorcycle engines and some large diesel Fig2.3: Two-stroke engine THE ENGINE 2 Technical English for AUTOMOTIVE ENGINEERING. 8 applications. Since the new gas pushes out the burnt gas, the intake and exhaust gases are not clearly separated. As a result, fuel consumption is relatively high and cleaning of the exhaust gas by a catalytic converter is difficult. 1.2. The diesel engine The name diesel comes from the inventor of the diesel engine, R. Diesel. There are both four- and two-stroke-cycle diesel engines. Most automotive diesels are four-stroke engines. The intake stroke on the diesel engine draws only air into the cylinder. The air is then compressed during the compression stroke. At near maximum compression, finely atomized diesel fuel (a gas oil having a high flashpoint) is sprayed into the hot air, initiating auto ignition of the mixture. During the subsequent power stroke, the expanding hot mixture works on the piston, then burnt gases are purged during the exhaust stroke. Since diesel engines do not use a spark plug, they are also referred to as compression ignition (CI) engines. In the case of petrol engines, too high a temperature in the combustion chamber ignites the petrol spontaneously. When this occurs, the plug cannot control the moment of ignition. This unwanted phenomenon is often referred to as ‘knocking’. The diesel is an injection engine. A petrol engine normally needs a throttle valve to control airflow into the cylinder, but a diesel engine does not. Instead, the diesel uses a fuel injection pump and an injector nozzle sprays fuel right into the combustion chamber at high pressure. The amount of fuel injected into the cylinder controls the engine power and speed. There are two methods by which fuel is injected into a combustion chamber, direct or indirect injection. With direct injection engines (DI) the fuel is injected directly into the cylinder and initial combustion takes place within the bowl that is machined into the piston head itself. With indirect injection engines (IDI) the fuel is injected and initial combustion takes place in a small pre combustion chamber formed in the cylinder head. The burning gases then expand into the cylinder where combustion continues. 2. Advantages and disadvantages of reciprocating engines -> An engine with a piston-cylinder mechanism has the following advantages: a. It is possible to seal the gap between the piston and the cylinder, resulting in high compression ratio, high heat efficiency and low fuel consumption. b. The piston ring faces the cylinder bore wall, separated by an oil film. The resulting hydrodynamic lubrication generates low friction and high durability. c. The piston loses speed at the dead-center points where the travelling direction reverses, which gives enough time for combustion and intake as well as for exhaust. -> However, the reciprocating engine also has disadvantages: a. The unbalanced inertial force and resulting piston ‘slap’ can cause noise and vibration. b. It is difficult to reuse the exhaust heat. Fig 2.4: Basic parts of a diesel engine THE ENGINE 2 Technical English for AUTOMOTIVE ENGINEERING. 9 3. The rotary engine (Wankel engine) The rotary-piston engine (or Wankel engine, named by its inventor) generates power by the compression, ignition, and expansion of gasoline/air mixture in a 4-stroke cycle in the same way as conventional internal combustion engines. The completely different mechanical design allows all moving parts to have a continuous rotary motion instead of a reciprocating movement. The rotor (or piston) is roughly triangular shaped and rotates on an eccentric on the output shaft within a housing of epitrochoid shape. The term is given to the path described by a point within a circle rolling around another circle. Fig 2.5: The Wankel rotary engine cycle III. NEW WORDS Look up for the new words Bonnet (n) Crankshaft Cylinder head Exhaust valve Valve lifter Lambda sensor Valve spring Inlet valve Camshaft Catalytic converter Fuel injector Spark ignition (SI) engine Valve seat Exhaust manifold Intake manifold Ignition plug Camshaft drive chain Piston Combustion chamber Scavenge (v) Cylinder Connecting rod Crank case Air-fuel mixture Compression ignition (CI) engines Spontaneously Phenomenon Referred to Knocking Injector nozzle Direct injection engines (DI) Indirect injection engines (IDI) IV. COMPREHENSION QUESTION 1. What is the role of engine in cars? 2. How many types of reciprocating engine? 3. Name 4 strokes of the 4-stroke engine? 4. How are the air and fuel mixture drawn into combustion chamber in intake stroke?