Hi guys, I have a very basic question which I have never been able to completely grasp the concept behind. This is regarding the Working Of A Flywheel. My question is: The Flywheel is said to store the kinetic energy from the excessive power produced during the power stroke and return it in the idle stoke to run the crank upwards to the T.D.C. And in the course it is said to SMOOTH OUT the fluctuation in the power produced in the power stroke. It is said that the flywheel absorbs energy by accelerating and supplies /gives back energy by decelerating. Now the purpose of the flywheel is said to be SMOOTHING THE FLUCTUATION in the power> i.e. To regulate the variation in the speed (angular) of the crankshaft due to variable power produced throughout the power stroke > i.e. to regulate and maintain a nearly uniform angularvelocity/rotational speed of the crankshaft/ultimately the jerking linear speed of the vehicle. (had the flywheel not been there) But what I couldnt really grasp was that: 1. How actually does the extra power surge (in the first 90 degree of crank angle) gets absorbed by the flywheel (being connected to the crankshaft)? Wouldnt the flywheel simply get turned with a variable angular velocity throughout the power stroke as the the torque produced at the crank is continously varying due to varying force at the crank. i.e the the flywheel will rotate at a varying angular speed (increasing continously throughout the stroke) And inturn wouldnt the crankshaft itself rotate at the same (varying - increasing) speed as that of the flywheel (due to flywheel being mounted on the crankshaft so they both will have same angular velocity at any instant) 2. And if this is the case How come the flywheel serve the purpose of Smoothing Out the fluctuation in speed? Wouldnt it keep on accelerating during the power stroke and then keep on decelrating in the next stroke and so would do the cankshaft resulting in a faster - slower type of speed at wheels (assume no transmissions for simplicity of theory) 3. HOW ACTUALLY IS THE ENERGY ABSORBED and HOW ACTUALLY IS THE SPEED/POWER FLUCTUATION SMOOTHED OUT? 4. Does really a flywheel be needed to give motion for the exhaust stroke as crank wheel will already have some inertial motion at the end of 90 degree crank angle which will drive the crank beyond the first half circle rotation? Please answer the 3rd question in maximum detail because my main intent is to build the clear concept of this. Thanks.