Working conditions carry a wide variation for the moving parts of a diesel engine. Depending on the intended use and components, a lubrication systems company selects the most appropriate type.
Why Lubrication is Necessary
No matter the smoothness of different surfaces, each one has its own distinct irregularities based on the type of material from which it is made.
Basically, the two solid surfaces become pressed or each other. Some may even slide across each other. Regardless, the real contact that occurs between the two causes friction that leads to the production of heat.
While each surface moves, plenty of frictional heat evolves at the point where the materials rub together. The result is high local temperatures that occurs, even under different speeds and light loads. Wear and tear also occurs on the surfaces.
For small loads, local pressure where the peaks of metal meet can be sufficient enough to cause the material to become deformed in ductile metals. When two materials that are different harden over one another, the softer metal peaks break easily, unlike harder metal peaks.
Lubrication is necessary to reduce the resulting friction that occurs between each moving surface. Additionally, using lubrication becomes a form of coolant to carry heat away from the surfaces. This allows proper lubrication for the moving parts, which ensures the affected machinery or engine operates the right way.
Types of Lubrication
There are different types of lubrication that applies to these functions. This is not unusual when you consider how moving and sliding surfaces perform during this process. These can include:
- Thick film lubrication
- Hydrostatic lubrication
- Hydrodynamic lubrication
- Thin film lubrication
- Boundary lubrication
- Extreme pressure lubrication
Using hydrodynamic lubrication or thick film lubrication as examples, consider what happens when a separation occurs between moving surfaces under the pressure of an unbroken layer of lubrication or film.
In general, the basis for using the hydrodynamic lubrication is to ensure the oil film completely takes the load. The basis of this type of lubrication in forming the oil wedge sets the foundation. Once the journal rotates, an oil taper is created, which leads to a wedge formed between the two surfaces. Pressure builds up while the oil film supports the load.
Another important point for this example is understanding that hydrodynamic lubrication is dependent upon the relative speed that exists on different levels. Load, oil viscosity, surfaces and clearance are all part of how well this lubrication system is prepared to perform.