The flywheel (fig. 3-45) stores energy
from the power strokes and smoothly delivers it to the drive train of the vehicle between
the engine and the transmission. It releases this energy between power impulses, assuring
fewer fluctuations in speed and smoother engine operation. The flywheel is mounted at the
rear of the crankshaft near the rear main bearing. This is usually the longest and
heaviest main bearing in the engine, as it must support the weight of the flywheel.
on large, low-speed engines is usually made of cast iron. This is desirable because the
heavy weight of the cast iron helps the engine maintain a steady speed. Small, high-speed
engines usually use a forged steel or forged aluminum flywheel for the following reasons:
cast iron is too heavy, giving it too much inertia for speed variations necessary on small
iron, because of its weight, pulls itself apart at high speeds due to centrifugal force.
with a manual transmission, the flywheel serves to mount the clutch With a vehicle that is
equipped with an automatic transmission, the flywheel supports the front of the torque
converter. In some configurations, the flywheel is combined with the torque converter. The
outer edge of the flywheel carries the ring gear, either integral with the flywheel or
shrunk on. The ring gear is used to engage the drive gear on the starter motor for
cranking the engine.