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mike_29904

2 stroke engine

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Hello Machies,

Thanks for being here for my question.

Without wasting time let me take you to my question.

As you all know that in 2 stroke engine there are two strokes.

First one is for expansion (exhaust) and the second one is for compression (ignition).

It's self explanatory that why piston goes downwards in expansion stroke..

But immediately after the 1st stroke why automatically piston goes upwards?

Is there any force that makes piston to move upwards?

Your answers are greatly appreciated. :)

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it is easy to understand,

the basic fact is due to inter connectivity of all with each other like crank,connecting rod, piston, when there is a blast in cylinder in power stroke, the gas pressure tends to push the piston downward & we get power in shaft. but we can't get 100% power on crank for our use. some power is used for next compression.

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The answer you seek is "inertia". The crank is ALWAYS connected to a flywheel which stores sufficient energy from the combustion- (or down-) stroke to power the compression stroke.

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As we know that when gases are heated up they move rapidly in all directions having a greater force than the cooled air. so when the gases burn up it exerts pressure on the lower side of piston trying to expand and as the piston is attached with links to camshaft , camshaft rotates and piston movement takes place

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Just because of crank, which converts reciprocating motion of piston into circular motion during power stroke and circular motion of flywheel to reciprocating motion of piston during compression stroke. So after completeing the power stroke(expantion stroke) i.e. after moving from TDC to BDC the piston moves from BDC to TDC as it is connected to crank with the help of connectting rod. Flywheel stores energy during power stroke and crank utilize this stored energy to push piston towards TDC during compression.

On more thing you need to point out that during power stroke, expantion takes place in the cylinder but below the piston, in the sump a compression begins to develop which creats a diffrence in pressure in the sump and the cylinder. As soon as piston open the inlet this diffrence in pressure create a flow of charge(Air fuel misxture) from sump to cylinder due to pressure difference.

And this flow of charge is only resposible for removal of exhaust gases from exhaust valve at the same time.

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