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Page 1: Camshafts

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Page 2: Camshafts

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Internal Combustion Engines

8. Study the designs of DOHC used in various automobiles. Analyze the designs of intake and exhaust camshafts used in Toyota Corolla twin-cam engine. Use pro–e software for analysis.

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Internal Combustion Engines

Group

Members

NS Esaa

m Jamil

TC Uzair

Ali

TC Hassa

n Warriach

Degree-30 Mechanical (A)Project supervisor:Sir Col. Ikhlaq Khattak

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Overview of our presentationCamshaft Its material and manufacturing Its types (OHV,SOHC,DOHC)Design of DOHC in various automobilesEngine specs of Toyota corolla used Design and study of intake and exhaust camshafts of Toyota twin cam engine using Pro-e Stress analysis of intake and exhaust camshafts of Toyota twin cam engine using Pro-eConclusions from Stress analysisQ & A session

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Camshaft“A camshaft translates the rotary motion of the engine

to the reciprocating motion that is used to operate (open or close) the intake and exhaust valves”

It has cam lobes on the shaft.The crankshaft drives the camshaft by camshaft

drivers (gear, belt or chain) The camshaft pushes the valves.The valves are pushed back by the reactive force of

the valve spring.

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Material and manufacturing of camshaft:Chilled iron casting:Relatively cheaperGood choice for high volume productionHas a resistance against wear

Billet steel:Used for high quality camshaftUsed for low volume productionMore time consuming processMore expensive than other methodsFinished product is far superior

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Types of camshaft:1) Push rod or OHV: The

camshaft is installed inside the engine block and valves are operated through lifters, pushrods and rocker arms.

Very simple, compact and durable.

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2) SOHC: The camshaft is installed in the cylinder head and inlet and exhaust valves are operated either by the rocker arms or directly through the lifters.

Easy to achieve perfect timing at high rpm

Higher engine speeds and power output.

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3) DOHC or Twin-OHC: It use two camshafts, one drives the inlet valves while the other exhaust valves through the valve lifters.

4 valves per cylinder allow

gases to flow freely. Can produce more HP with

smaller engine volume. High efficiency. Commonly used now-a-days Complex & expensive design

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Designs of DOHC used in various automobiles:

Harley Davidson bike (left), its engine (upright) and its DOHC design (bottom right)

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Designs of DOHC used in various automobiles:

Mitsubishi Galant (left), its engine (upright) and DOHC design (bottom right)

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Designs of DOHC used in various automobiles:

Toyota Corolla (left), its engine (up right) and its DOHC design (bottom right)

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Engine specifications of Toyota Corolla used design and analysis in Pro-e:

Engine: 1.8 liter four cylinders, double overhead cam, four valves per cylinder, 2006 model Horsepower: 126 @ 6,000 rpm Torque: 122 lb.-ft. @ 4,200 rpm Transmission: 5-speed manual

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Designs of intake camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Designs of intake camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Designs of exhaust camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Designs of exhaust camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Study of designs of intake and exhaust camshafts:

The rotating speed of camshaft is half of crankshaft speed in gasoline engine and equal in diesel engine. The design of the cam lobe contour has a major effect on the engine performance.

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Study of designs of intake and exhaust camshafts:

The amount of valve opening, how long the valve remains open, when the valves open and close and the speed at which valves open and close are all determined by the cam lobe design.

To avoid wearing due to friction between cam lobes and cam follower, there are holes on the camshaft which provide way to oil for lubrication.

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Stress analysis of exhaust camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Stress analysis of exhaust camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Stress analysis of intake camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Stress analysis of intake camshaft of Toyota Corolla twin-cam engine, using Pro-e:

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Conclusions from the stress analysis of intake and exhaust camshafts:

One pair of the rotating cam lobe pair touch to exert force to open the valve pair at one time while the remaining are oriented at different angles.

One end (the shaft in bearing side) cant displace horizontally while the other end (the shaft attached to the gear) is free to move horizontally.

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Conclusions from the stress analysis of intake and exhaust camshaft:

The forces are acting on the cam lobe pair (as reaction of valve spring) nearest to the gear. Stresses are more near the bearing side and displacement is more near the gear side. Stresses are maximum around the holes of oil due to stress concentration. Stress is more at the region where the shaft changes diameter.

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THANK YOU!

Q & A Session