Lots of very insightful comments already, I only have one thing to contribute, which is a spelling correction: "Since the piston moves down twice and up twice,

Lots of very insightful comments already, I only have one thing to contribute, which is a spelling correction: "Since the piston moves down twice and up twice, it does a total of four strokes and the engine we’ve build is known as a four-stroke engine. Notice that it takes two revolutions of the crankshaft for the piston to do one full cycle of the work as it goes through the four phases: intake, compression, power, and exhaust." It should be: "the engine we've built", with a 't', not a d. /pedantry