Flywheel

We got a new car (used car, but new to us) and I noticed that it doesn’t want to stop very easily when the gas pedal is lifted.

In other words, instead of immediately slowing like our older car, this car just keeps on going.

This makes me wonder if perhaps it has a flywheel inside the engine somewhere.  

Fly wheel.

What is a fly wheel?  I think I know… or used to know… but I realize I have no idea if such a thing still even exists in a modern automobile.

When I was a boy my Mom told me about a “fly wheel” and I thought it was really really really really interesting…  as if it’s energy stored inside a big heavy wheel.  What’s the word for this energy?  It’s the kind of energy you store when you stretch a rubber band…   ummm…. “kinetic” energy?

Well, time to stop wondering and start learning:

http://en.wikipedia.org/wiki/Flywheel

Excerpt:

“A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed. Energy is transferred to a flywheel by applying torque to it, thereby increasing its rotational speed, and hence its stored energy. Conversely, a flywheel releases stored energy by applying torque to a mechanical load, thereby decreasing its rotational speed.”

Okay, that makes sense!

Now this one is a bit over my head:

“The phenomenon of precession has to be considered when using flywheels in vehicles. A rotating flywheel responds to any momentum that tends to change the direction of its axis of rotation by a resulting precession rotation. A vehicle with a vertical-axis flywheel would experience a lateral momentum when passing the top of a hill or the bottom of a valley (roll momentum in response to a pitch change). Two counter-rotating flywheels may be needed to eliminate this effect. This effect is leveraged in reaction wheels, a type of flywheel employed in satellites in which the flywheel is used to orient the satellite's instruments without thruster rockets.”

One day I think I’ll need to reserve an hour or two to just peruse this article and try to soak it in.