Unfortunately, it doesn’t make your car fly. It does do some really neat other stuff though. It’s actually critical to any car with a manual transmission. It’s bolted to the crankshaft and serves as the mechanical connection between the crankshaft and the transmission. It also starts the car and makes sure it’s comfortable when it is running.
What is a flywheel?
It’s more of a metallic plate that has gear teeth around it’s diameter. Bolted between the engine and the transmission, it spins when the engine is running. The metal is typically cast iron, forged steel, or even a lighter aluminium alloy in race cars.
It is weighted to ensure that while it spins it keeps the engine balanced and smooth. This helps keep power delivery linear and without vibration.
What does a flywheel do?
The flywheel does a raft of things:
- Gives the clutch plate a surface to connect to. This allows for kinetic rotational energy to connect to the transmission, through the gear and to the wheels. When the clutch pedal is depressed it disengages the transmission from the flywheel.
- Starts the car. You starter motor has a gear that shoots out and slots into the teeth of the flywheel. It then spins the flywheel to crank the engine over. Once it fires up and runs, the gear disengages and returns into the starter motor.
- Stops vibrations and helps the engine to run at idle. By being weighted and reasonably heavy, by rotating it helps store kinetic energy. It can transfer this rotational energy back into kinetic energy when the engine is at idle.
How does a flywheel work?
Well you know what it is and what it does, how does it do it?
The engine does all the work really, the flywheel is rotated by the crankshaft. It needs to be bolted to the crankshaft so that when the clutch is disengaged it can connect the two. It’s a harder metal than a clutch so that it doesn’t wear out.
When it rotates, it rotates the clutch and thus the driveline and wheels. When it is independent of the transmission, like at idle, it helps keep the engine running. How? Well, by spinning it rotates at the same speed as the crankshaft. By being heavy and weighted, it can help the engine to keep turning by returning it’s rotational energy to the crankshaft when the engine stumbles.
Basically smoothing out the whole operation. One toothy metal disc-wheel-plate thing. Pretty neat really.