内燃机1 1

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Internal Combustion Engines

Su Qingyunqingyun@dlut.edu.cn

andTang YunBang

tybang@dl.cn2007.9.5

Power Engineering and Machinery Essential

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A good beginning is half done

Do it now

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Course introduction

• Limited selective course• Duration of the course ： 32 hours• Final examination ： pen exam• Contents and course structure ： The course is

divided into two terms:• In the first term, students may learn some intro

ductive materials about thermal and power engineering, including internal combustion engine, turbo-machinery, thermal engineering and refrigeration & low temperature engineering .

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Course introduction (continued)• Internal combustion engine-working principl

e of ICE and Functions of main components• Turbo-machinery-the fundamental knowledg

e of steam turbine, compressor and gas turbine. (Professor Wang)

• Thermal engineering-fossil fuel power plants and atomic fuel power plants (Professor Shen)

• Refrigeration & low temperature engineering –basic vapor-compression refrigeration cycle and absorption system. (Dr. Zuo)

• In the second term, students will learn some specific basic knowledge in their major fields.

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Course introduction (continued)

• The course is designed so that you will know all the aspects about thermal and power engineering rather than to limit your knowledge to only one specific area. The four parts of the course are equally important. The scores for the final examination is evenly divided between the four parts. So you must study every part very carefully.

• Basic requirements ：– Attending the class– Taking note– Mutual communication, seminar (discussion)

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Internal combustion engine

Reference book:

1. Teaching materials

2. English reading course for specialty of automobile 《汽车英语阅读》 哈尔滨工业大学出版社

3. 《 Power 》 Joseph. Duffy

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LEARNING OBJECTIVES

Upon completion of this part, you should be able to do the following:

• Grasp the definition of the basic terms of ICE.

• Explain the principles of a combustion engine.

• Explain the process of an engine cycle.

• State the classifications of engines.

• Discuss the construction of an engine.

• List the auxiliary assemblies of an engine.

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Internal combustion engineMain contents:

1. The introduction of I.C.E (Chapter 1)

(I.C.E and E.C.E, early development)

2. The working principle of I.C.E (Chapter 1)

(4-cycle and 2-cycle engine, comparison)

3. Reciprocating engine design (Chapter 2)

(classification and main components )

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Chapter 1 internal combustion engine

1.1 combustion engines1. Combustion engine is a machine

that converts heat energy into mechanical energy.

Internal combustion engine

External combustion engine

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2. Definition of I.C.E and E.C.E I.C.E (internal combustion engine) -----is any engine that operates by

burning its fuel inside the engine.

E.C.E (external combustion engine) -----is any engine that operates by

burning its fuel outside the engine.

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3.simple external and internal combustion engine

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• External combustion engine Fuel (chemical energy) burning-

heat energy-outside of boiler-water-steam-force the piston to move (mechanical energy).

• Internal combustion engine Fuel (chemical energy) burning-

heat energy-inside of cylinder-expanding gases-force the piston to move (mechanical energy).

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4.Three elements which all ICEs rely on:

Fuel: contains potential energy for operating the engine.

Air :contains oxygen necessary for combustion.

Ignition: it can start the combustion.

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1.2 I.C.E versus E.C.E

(1) Similarity: ① both are heat engines.

② energy transforms in the

same way -reciprocating motion

to rotary motion

(2) Differences: the fuel burns in different place① ②the combustion rate

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1.3 Early development (1) The first reciprocating I.C.E • a. in 1680, the first reciprocating I.C.E. was mad

e by Christian Huygens, a Dutch scientist. • b. gunpowder explosion -----piston move upwar

d------gases were cooled----piston move downward• c. provided inventors with a fundamental idea(2) Static spark ignition • a. In 1799, Philip Lebon patented the first success

ful gas engine. • b. air and fuel -ignited by an electric spark-----pus

h the piston move back and forth• c. static electricity is unreliable and much depend

ed on atmospheric condition.

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(3) Gas flame ignition• In 1823, Samuel Brown invented a gas engine. • the mixture is ignited by a constantly lighted

gas flame which situated outside of the cylinder.

(4) Separate compression pump • In 1838, William Barnet patented a gas engine,

which compressed the gas and air mixture with a separate pump.

(5) First practical engine • In 1860, Pierre Lenoir constructed the first

practical gas engine. • The mixture is drawn into the cylinder and is

ignited by electric spark from an induction coil.

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(6) Four cycles

In 1862, Beau Derochas described the principle of four cycles. It is the foundation of the modem internal reciprocating engine.

• a. Suction of gas and mixture• b. Compression of mixture • c. Ignition and expansion of mixture• d. Exhaust of burned gases

(7) Otto engine In 1876, Otto designed the engine with higher

efficiency based on this four cycles principle.

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(8) Gasoline engine In 1885, Gottlieb Daimler patented the first

gasoline engine. This engine worked on the four-cycle principle and the gasoline was vaporized with the carburetor.

(9) Diesel engine In 1892, Rudolph Diesel patented the new

compression ignition engine. This engine employed compression high enough to ignite the mixture of oil and air. Today diesel engine is named in honor of Mr. Diesel.

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1.4 Development of power1.How does the power of an ICE produce ?

It comes from the burning of a mixture of fuel and air in a small, enclosed space.

fuel-burn-gas expanding-piston moves-cranking the engine-wheel-vehicle

2. How does the power transmit to the wheel?

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Cylinder, piston, connecting rod, and crankshaft for a one-cylinder engine.

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• The cylinder is closed at one end by the cylinder head.

• Inside the cylinder is the piston, a movable metal plug that fits snugly into the cylinder, but can still slide up and down easily.

• This up-and-down movement, produced by the burning of fuel in the cylinder, results in the production of power from the engine.

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• The crankshaft is a shaft with an offset portion-the crank— that describes a circle as the shaft rotates.

• The top end of the connecting rod connects to the piston and must therefore go up and down.

• Since the lower end of the connecting rod attaches to the crankshaft, it moves in a circle; however it also moves up and down.

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• When the piston of the engine slides downward :

• The upper end of the connecting rod moves downward with the piston in a straight line.

• The lower end of the connecting rod moves down and in a circular motion at the same time.

• This moves the crank; in turn, the crank rotates the shaft.

• Drive the wheel to rotate.