HU 121 History of Engineering and Technology Fall 2013/14 Pharos University in Alexandria Faculty of Engineering Engines Lect5

HU121_Lect5_Engines2 Outline Engines –Definition –Types The Cam –Al Jazari Engines –Al Jazari Cam Pumps Internal Combustion Engine

HU121_Lect5_Engines3 Engines An engine converts energy Into useful mechanical motion. Lecture 7 ? Mechanisms

HU121_Lect5_Engines4 Al Jazari The first known engines were described by Al Jazari in the 13 th 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 أبُو اَلْعِزِ بْنُ إسْماعِيلِ بْنُ الرِّزاز الجزري

HU121_Lect5_Engines5 Al Jazari Major Mechanical Devices Cam Crankshaft and crank- slider mechanism Water-raising machines Automata Clocks

HU121_Lect5_Engines6 Al Jazari Double-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.

HU121_Lect5_Engines7 As the animal walks in a circle the horizontal axle is turned by the gears and the end of the crank slides in the hinged connecting rod causing it to oscillate around its hinge and thus causing the swape to rise and fall. Fig 3 is a line drawing of the mechanism for this machine

HU121_Lect5_Engines8 Al Jazari’s Camshaft The camshaft was conceived and described by Al-Jazari in 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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HU121_Lect5_Engines11 Internal Combustion

HU121_Lect5_Engines12 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.

HU121_Lect5_Engines13 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.

HU121_Lect5_Engines14 Multiplex Pump

HU121_Lect5_Engines15 Review Questions 1. Al Jazari is considered one of the founders of modern engineering. (a)In what century did Al Jazari live? (b)List five of his major engineering contributions 2. Discuss the main features of Al Jazari Double- acting Piston Engine 3. Describe briefly the role of the cam mechanism in (a) An internal combustion engine and (b) A suction pump