How a Two Stroke Engine Works 3

How a Two Stroke Engine Works

As w seen from the previous page, the piston is forcing the fuel/oil and air mixture to go from the crankcase into the cylinder head where it can be ignited –

 

how a two stroke engine works 10

how a two stroke engine works 10

However, this leaves no fuel in the crankcase for the firing after that one,


the piston is about to suck in more fuel for that firing now. Now the piston begins to go upwards (under the momentum of the flywheel) and it covers the top section of the transfer port and uncovers the inlet port just below the piston. This creates a vacuum in the crankcase

how a two stroke engine works 11

how a two stroke engine works 11

 

This has the effect of sucking in a new fuel/air/oil mixture into the crankcase which can be ready to be forced up into the cylinder when the piston starts its down-stroke again after being fired, but lets not get ahead of ourselves yet and finish off one full 2 stroke cycle

how a two stroke engine works 17

how a two stroke engine works 17

As the piston continues on its upstroke it has already sealed off the transfer port, soon it will also seal off the exhaust port, this will mean the fuel/oil/air mixture is trapped in the cylinder head of the two stroke engine –

how a two stroke engine works 14

how a two stroke engine works 14

 

Now all that is left is for the spark plug to ignite the


mixture and the cycle will begin again –

how a two stroke engine works 1

how a two stroke engine works 1

 

You can watch  video showing all of these steps in an animation below, hopefully it will make it easier to understand –