HU 121 History of Engineering and Technology

Fall 2012/13

Pharos University in AlexandriaFaculty of Engineering

Engines

Lect6

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Outline• Engines

– Definition – Types

• The Cam– Al Jazari Engines– Al Jazari Cam

• Pumps• Internal Combustion Engine

Review Questionsat the end

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Engine

An engine converts energy

Into useful mechanical motion.

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Types of Engines

1. Water-driven Engine (water wheels --> water turbines)

2. Wind-driven Engine

3. Steam Engine

4. Internal Combustion Engine

5. Electromagnetic Engine (Motor)

6. Jet Engine

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Al Jazari• The first known engines were

described by Al Jazari in the 13th century.

• Al-Jazari inherited the knowledge of his predecessors, but he improved on their designs and added his own.

• His book Al-Jami’ bayn al-Ilm wal Amal Al-Nafi’ fi Sina’at Al-Hiyal (Book of Knowledge of Ingenious Mechanical Devices) is a pioneering book in engineering.

• This book was translated to English by Donald Roultedge Hill in 1947.

ب�ن� أ ماع�يل� إس� ب�ن� �ل�ع�ز� ا ب�والجزري زاز الر�

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Al Jazari Mechanical Devices

• Cam• Crankshaft and crank-

slider mechanism• Water-raising

machines• Automata • Clocks

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Evolution of the Camshaft

Roman sawmill camshaft

3rd century

Al Jazari Water Raising Engine

13th Century

da Vinci crank and rod 16th Century

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Cam Shaft

Converts up and down or reciprocating motion into rotary motion or vice versa.

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Al Jazari’s Camshaft• The camshaft was conceived and

described by Al-Jazari in 1206. • He implemented the camshaft

as part of – automata, – water-raising machines, and – water clocks.

• The cam and camshaft later appeared in European mechanisms from the 14th century.

• The camshaft is an essential mechanism for conceiving

and designing the Internal combustion engines and pumps.

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Al JazariDouble-acting Piston Engine

Main Features:1. it converts rotary motion

into reciprocating motion through the crank-connecting-rod mechanism.

2. it employs a double-acting principle (at the same time as one piston sucks, the other one delivers the water).

3. it is the first pump known to have had true suction pipes.

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Internal Combustion

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The Role of the Cam in an Internal Combustion Engine

• In the internal combustion system the cam and follower system are required to control the opening and the closing of the inlet and exhaust valves.

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Cam Pump

The follower is cylindrically shaped and moves within a tight fitting cylinder so liquid is sucked in and pushed out as the follower moves up and down.

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Multiplex Pump

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Review Questions1. (a) Define an engine

(b) List four types of engines in chronological order

2. (a) Sketch and describe a Camshaft(b) Name two modern applications of camshafts

3. Al Jazari is considered one of the founders of modern engineering.(a) In what century did Al Jazari live?(b) List his major engineering contributions

4. Discuss the main features of Al Jazari Double-acting Piston Engine

5. Describe briefly the role of the cam mechanism in(a) An internal combustion engine and(b) A suction pump