Flywheel calculations

[LCT]

I'm trying to figure out the optimal moment of inertia for our flywheel, since I have to compensate for our primary CVT clutch as it acts as a flywheel itself. The calculation I've found is I=E/(k(w^2)). I know k and w, but E seems to be calculated from the area under the torque curve of the engine for a full cycle and I don't have a program that will calculate it. Does anyone know of a way to calculate either the E or I values, and has anyone optimized their flywheels in the past?

[LCT]

I'm trying to figure out the optimal moment of inertia for our flywheel, since I have to compensate for our primary CVT clutch as it acts as a flywheel itself. The calculation I've found is I=E/(k(w^2)). I know k and w, but E seems to be calculated from the area under the torque curve of the engine for a full cycle and I don't have a program that will calculate it. Does anyone know of a way to calculate either the E or I values, and has anyone optimized their flywheels in the past?

[Pete M]

Engine flywheels are more about trading off tolerable engine vibration (F1 very different to your mum's street car), ease of launching (hard to launch with less inertia), and lesser inertia to accelerate.

I'd argue that for FSAE "as little as possible" is a decent rough guide but i'm sure there is a limit somewhere.

[adrial]

I would calculate the moment of inertia of the factory flywheel.

I would try to keep the combined moment of inertia of the CVT and the flywheel near the moment of inertia of the factory flywheel. This way you ensure you haven't made anything worse.

Testing is the only way to be comfortable with reducing the weight of the flywheel IMO. Shave one and see how it works. There is a point where it is TOO light, especially with a student built fuel injection system.

[VFR750R]

formula 1 cars don't have flywheels, they even have the clutch mounted to the transmission meaning even less engine side inertia once clutched.
sprint cars don't have flywheels. stock cars do...because they are mandatory.
once you're moving lighter is always better.
helps shifting, decreases engine braking, decreases loading on drivetrain.
some arguement could be made for reliability in larger engines but 600cc 4 isn't twisting crank much. Some road racers and many drag racers eliminate the flywheel.

keep in mind, it is also your source of battery charging. adding an different alternator defeats the purpose, unless the stator is outside the flywheel instead of nested inside.

[rjwoods77]

If you give me a call I can lay it all out for you since Ian and I looked into this a whole bunch. Up to you if you want to save a whole bunch of time since I can greatly accelerate your learning curve. Get my number from JR or Wes.

Rob Woods