LUBRICATION FEATURES OF A LARGE DIESEL ENGINE

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In some engines such as long and superlong stroke engines, the piston is not directly connected to the crank pin via a connecting rod.
The piston has a piston rod extending from the bottom of the piston.
The piston rod is then connected to the connecting rod at the crosshead bearing.
The crosshead bearing has a to and fro motion and therefore a continuous hydrodynamic film cannot form.
Therefore oil has to be pumped to the crosshead bearing at a predetermined pressure in order to take the loads of compression and combustion.
The crosshead is connected to the crank pin via a connecting rod.
In some engines, lubricating oil in the cylinder is different from the oil supplied to the other bearings.

The cylinder oil contains additives to withstand the high temperatures and contaminants from combustion products.

The oil is slightly basic in nature to counter the acids formed from combustion.

Scraper rings spread the oil over the liner surface.

Lub. oil is usually injected between the two scraper rings.

Oil is injected at a predetermined period during the downward stroke.

Before starting, oil is pumped into the liner by manual priming methods.

After starting, the oil pump is driven by the engine through a cam shaft.