I was reading about a four stroke cycle. Here's what I understood:
- In the first stroke, the piston starts at the top and moves down.
- In the second stroke, the piston moves upwards.
- In the third stroke, the piston moves down due to the combustion by spark plug.
- In the final stroke, the piston moves up and the cycle continues.
I can understand why the piston moves down in third stroke due to the gasoline explosion. But, what moves the piston up and down in Step 1, 2, and 4?