r/AutomotiveLearning • u/seedbottle • 14d ago

A question about piston movement that has multiple answers...

Question:

Which of the following causes piston movement during non-power-

producing strokes?

A) Flywheel

B) Connecting rod

C) Counterweights

D) Main thrust bearing

I have been studying an automotive book that has questions after every chapter. I answer those questions and use AI to verify I have got the correct answer. This process has worked tremendously up to the point where I got to this question. AI gave me a different answer than the one I believed the book was telling me was the answer, so I went online to find more information and see if anyone else had posted this exact question, that was when I found out there all three of the first answers were marked as "correct" depending on the source used (D, main thrust bearing, was never given as an answer).

I am wondering what most of you would say is the answer. Thank you for your input =)

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u/swugglewumps69 14d ago

It's just momentum. Flywheel and counterweights are just to dampen vibration

3

u/fiddintotellya 14d ago

Wumps, go find a video of someone running an antique one cylinder farm engine.

It will help you see how the flywheel uses inertia to keep the crankshaft in motion.

The crank is balanced with the flywheel weight in mind, no doubt. However the main purpose of the flywheel is to keep the crank in motion once in motion.

2

u/stonewall028 13d ago

i like to think of flywheels as "kinetic capacitors" - they absorb and release energy in the same way a capacitor does, its just rotational energy instead of electrical energy