Im confused with the four stroke engine. How does it actually works? so far i understand that mix air and fuel enters into the intake cylinder the valve closes and the piston goes up to compress that mix air/fuel and the the spark ignites for combustion. the piston goes down again and the exhaus valve opens. Now my question is. the other 3 pistons work the same as intake? or how does it work. Im so confused. thank you to whoever helps me.

 

This helps a lot: http://auto.howstuffworks.com/engine1.htm