Oil pressure is an important factor in the longevity of most internal combustion engines. With a forced lubrication system (created by Frederick Lanchester), the oil is picked up by the positive displacement oil pump and forced through the oil gallery (aisle) to the bearings, such as the main bearing, large end bearings and ridge axle bearings or balance shaft bearings. Other components such as cam lobe and cylinder wall are lubricated by oil jets.
Adequate oil pressure ensures that the metal of the rotating shaft (journals) and the cushioned sheath can never touch, and wear is therefore limited to the start-up and shutdown. The oil pressure, combined with axis rotation, also hydrodynamically centers the journal in its shell and cools the bearing. Such bearings are known as fluid bearings.
The oil pressure is higher when the engine cools due to the increase in oil viscosity, and also increases with engine speed until the relief valve at the oil pump is open to divert excess flow. The lowest oil pressure under hotter idling conditions, and the minimum allowable pressure by factory tolerance is usually given at this point. Excessive oil pressure may indicate clogged filters, blocked oil galleries, or incorrect oil levels. Low oil pressure indicates worn bearings or crashed pumps.
Some vehicle engines have an oil pressure switch that lights warning lights at low oil pressure. Some vehicles have an oil pressure gauge on the dashboard or instrument cluster.
The oil pressure is created by fluid flow restrictions in the pump outlet line. Not as commonly believed, by the pump itself. The boundary becomes the big end and the main cushion, plus the camshaft and rocker gear if mounted.
Video Oil pressure
External links
- Low Oil Pressure Solution from AA1Car
Source of the article : Wikipedia
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