Diesel Engine Fundamentals
An internal combustion engine would not run for even a few minutes if the moving parts
were allowed to make metal-to-metal contact. The heat generated due to the tremendous
amounts of friction would melt the metals, leading to the destruction of the engine. To
prevent this, all moving parts ride on a thin film of oil that is pumped between all the
moving parts of the engine.
Once between the moving parts, the oil serves two purposes. One purpose is to lubricate
the bearing surfaces. The other purpose is to cool the bearings by absorbing the friction-
generated heat. The flow of oil to the moving parts is accomplished by the engine's
internal lubricating system.
Figure 12 Diesel Engine Internal Lubrication System