Question regarding four stroke engines

[scorpio.in]

I read the article about four stroke engines and how it works here - http://www.animatedengines.com/otto.shtml

But one question remains, where is the energy comes for

1) Expansion before starting the engine cycle - I think its from battery. Please correct me if i am wrong.

2) After the engine cycle is started.

2) Once expanded from where the energy to compress comes from? I heard it compresses 1/8 to 1/25th of the volume of the air and it requires lots of energy.

Please let me know

[curtis73]

The energy comes from two places; the combustion of other cylinders, and the energy stored in the flywheel.

The explosion of fuel pushes the cylinder down. Inertia carries it through the other three cycles. The weight of the flywheel, the crankshaft, and other rotating parts keep things going. In a multi-cylinder engine, there is always another cylinder on the combustion stroke pushing another cylinder on the other strokes.

Its a bit wasteful, but it works. The combustion "throws" the weight around enough to get it back to another compression stroke

The battery basically only runs the starter motor. After the engine is running, the only electricity used by the engine is the ignition system to spark combustion which is more than covered by the alternator.

[scorpio.in]

Thanks a lot for the reply. But i am not able to see the components you mentioned in the link i've given.

What exactly is a flywheel and a crank shaft?

Do you have a better link which explains the thing in detail for a newbie?

Even the torque, rpm terminology also i would like to have more info.

Originally Posted by curtis73

The energy comes from two places; the combustion of other cylinders, and the energy stored in the flywheel.

The explosion of fuel pushes the cylinder down. Inertia carries it through the other three cycles. The weight of the flywheel, the crankshaft, and other rotating parts keep things going. In a multi-cylinder engine, there is always another cylinder on the combustion stroke pushing another cylinder on the other strokes.

Its a bit wasteful, but it works. The combustion "throws" the weight around enough to get it back to another compression stroke

The battery basically only runs the starter motor. After the engine is running, the only electricity used by the engine is the ignition system to spark combustion which is more than covered by the alternator.

[shorod]

Try this - http://auto.howstuffworks.com/engine1.htm

-Rod