Lube Oil System of Diesel Engine

by Starlight Generator dieselgeneratortech

The lube oil system of the diesel engines lubricates the rotating and moving parts and gears of the engine to minimize the effects of metal to metal contact that causes both sliding and rolling types of friction, and to absorb great amount generated heat to achieve smooth performance and lengthening the life of the internal parts of the engine.

Functionally, the main task of the lube oil system in the diesel engine is to supply the clean lubrication oil under the required pressure and circulate it inside the engine.

In most of the diesel engines the lube oil system consists of a positive displacement gear pump, chain-driven from the crankshaft, draws lubricating oil from the engine oil pan and circulates it through the system. The oil passes through a suction strainer before entering the pump, then through proper filters and oil cooler before delivery to the engine parts.

Oil is accumulated and stored in the engine's oil sump where one or more oil pumps take a suction and pump the oil through one or more oil filters.

The main parts of the lube oil system are listed below:

1. Oil Pumps

2. Oil Filters

3. Oil Cooler

4. Oil manifold

5. Oil Sump

Depending on the service duty and size of the diesel engine the lube oil system components may be part of the engine package and engine-mounted on the skid which is the typical case for standby gensets, or may be stand-alone components, which is the case for large engines.

Oil Pumps details

The engine driven oil pump: usually positive displacement gear-driven pump. It pulls oil from the lube oil pan (sump) and supplies it to the engine when the engine is running.

Pre-lube oil pump: In the larger engines the pre-lube pump is generally a close coupled, self-priming, positive displacement pump of the rotary lobe or gear type.

Oil Filters

The function of the filters is to clean the oil and remove any metal that the oil has picked up due to wear, and depending on its temperature it may pass through the oil coolers or not before it goes to the engine bearing inside the engine through the oil main gallery inside the cylinder block.

Oil Cooler

The lube oil cooler assembly generally uses shell and tube heat exchanger. Depending on the lube oil flow rate, a single heat exchanger may be used or two or more units may be used.

Oil Manifold

The oil galleries distribute the oil to all the bearings surfaces in the engine.

Oil Sump

The oil sump is where the oil is accumulated and stored in the engine.