Oil filter

Other vehicle hydraulic systems, such as those in automatic transmissions and power steering, are often equipped with an oil filter.

The purpose of the bypass is to have a secondary filtration system to keep the oil in good condition, free of dirt, soot and water, providing much smaller particle retention than is practical for full flow filtration, the full-flow filter is still used to prevent any excessively large particles from causing substantial abrasion or acute blockage in the engine.

This situation can cause premature wear of moving parts due to initial lack of oil.

Mechanical designs employ an element made of bulk material (such as cotton waste) or pleated Filter paper to entrap and sequester suspended contaminants.

In the mid-1950s, the spin-on oil filter design was introduced: a self-contained housing and element assembly which was to be unscrewed from its mount, discarded, and replaced with a new one.

Ones that are made from completely synthetic material excepting the metal drain cylinders contained within are far superior and longer lasting than the traditional cardboard/cellulose/paper type that still predominate.

Pressurized oil enters the center of the housing and passes into a drum rotor free to spin on a bearing and seal.

The rotor has two jet nozzles arranged to direct a stream of oil at the inner housing to rotate the drum.

[5] HE oil filters typically have pore sizes of 3 micrometres, which studies have shown reduce engine wear.

Having determined the optimum target cleanliness level for a contamination control programme, many engineers are then challenged by the process of optimizing the location of the filter.

To ensure effective solid particle ingression balance, the engineer must consider various elements such as whether the filter will be for protection or for contamination control, ease of access for maintenance, and the performance of the unit being considered to meet the challenges of the target set.

Spin-on oil filter, showing annular seal and screw-on thread
Spin-on oil filter on a Saab
New (left) and used (right) motorcycle oil filters
Oil-filter cartridge, internal construction.
Replacement paper filter element for a Volvo
Motorcycle oil filters on Kawasaki W175. Old (left) and new (right).
Motorcycle oil filters on Kawasaki W175. Old (left) and new (right).