That is the heat source.
Now, let us take a look inside the crankcase. It houses the
crankshaft, connecting rod, piston rod, cylinder liner, piston,
drive gears or chains and the lubrication oil. To prevent
lubrication oil loss, protect persons from the moving mechanical
parts, prevent contamination of the oil, and many other reasons
the crankcase is totally enclosed and separated from the external
environment.
First, let us look at the moving parts. There is the reciprocating
mechanism consisting of the crankshaft, journal bearings, and
connecting rod. If it is a crosshead engine, the crosshead sliding
and reciprocating mechanism. For the trunk type engine, there is
the piston and the small end bearings.
There are also gears or chains to drive the camshaft.
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