the

overhead camshaft poppet valve engine

welcome to the video tutorials of

mechanisms by mechanism Euler here is an

animation of overhead camshaft poppet

valve engine this type engines are

widely used to power our cars there were

numerous attempts to replace these

engines but these engines endured the

test of time and nothing was successful

to replace them as you see this is a

four-stroke engine and Inlet and exhaust

valves are open only in one stroke at a

time with a phase shift the blue color

indicates the air inlet while the yellow

indicates the exhaust gases to

synchronize the camshafts two gears

rotating in opposite direction is

connected to a gear on crankshaft if we

summarize the operation in four-stroke

engine it goes as follows

in the first Stoke inlet valve is opened

an air-fuel mixture sucked into the

cylinder in the second stroke air fuel

mixture is compressed in the cylinder

during this operation Inlet and exhaust

valves are in the closed position just

before the third stroke the spark plug

ignites the mixture in the third stroke

due to high pressure created by burning

air & fuel mixture pushes the piston

away from cylinder head in the fourth

stroke burnout gases are exhausted to

the environment before I conclude the

presentation of this animation I want to

talk about stroboscopic effect

this is also called as wagon will effect

some time visitor watching my videos are

complaining that the will or a gear is

rotating in wrong direction in some of

my animations I pay a lot of attention

in the details of my animation and such

a mistake is very rare

please look at gears and cams in the

animation and pay attention of the

motion of black dots they are rotating

correctly however if I increase rotation

speed cams act normally but the gears

begin to act strangely this phenomenon

is exactly what happens in the wagon

wheels sometime they stop rotating then

they rotate in the opposite direction

and so forth

this is because we are recording videos

with a fixed frame rate at the same time

our computer screen refreshing with a

different rate this difference combined

with changing speed of rotation causes

this strange and annoying phenomenon

while single dot shows a continuous

rotation repeating futures such as gear

teeths

acting strangely and we can do nothing

about it thank you for taking the time

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