Oil/Lube Filter

An Oil/Lube Filter is a filter designed to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil. Their chief use is in internal-combustion engines for motor vehicles (both on- and off-road ), powered aircraft, railway locomotives, ships and boats, and static engines such as generators and pumps. Other vehicle hydraulic systems, such as those in automatic transmissions and power steering, are often equipped with an oil filter. Gas turbine engines, such as those on jet aircraft, also require the use of oil filters. Oil filters are used in many different types of hydraulic machinery. The oil industry itself employs filters for oil production, oil pumping, and oil recycling. Modern engine oil filters tend to be "full-flow" (inline) or "bypass".

History

The history of Oil/Lube Filter is a testament to the importance of maintaining engine cleanliness and performance. From the early days of rudimentary screens and strainers to the modern spin-on filters and advanced filtration technologies, oil filters have evolved significantly over time. As the automotive industry continues to grow and evolve, so too will the technology used to keep engines running smoothly and efficiently.

Early Developments

Early Filters: In the early days of automobile engines, there were no dedicated oil filters. Instead, simple screens or strainers were used to remove large particles from the oil. These early devices were rudimentary and often ineffective in removing finer contaminants.

Progression: As engine technology advanced, the need for more efficient oil filtration became apparent. The oil systems of early engines were gradually improved to include better filtration mechanisms.

Key Milestones

Full-Flow Filters: Full-flow oil filters, which filter all the oil flowing through the engine, emerged as a significant improvement over earlier designs. These filters were designed to remove a wider range of contaminants, improving engine performance and longevity.

Spin-On Filters: A major breakthrough came in 1954 when WIX invented the spin-on oil filter. This design revolutionized oil filter replacement, making it a quick and easy process. The spin-on filter is a self-contained unit that can be easily removed and replaced by unscrewing it from the engine block. This design has become the standard for most modern vehicles.

Technological Advancements

Materials and Design: Over time, the materials used in oil filters have improved significantly. Early filters were made of metal mesh or paper, but modern filters often use synthetic materials that offer better filtration efficiency and durability. The design of filters has also evolved, with many modern filters featuring pleated paper or synthetic media that provides greater surface area for contaminant capture.

Efficiency and Durability: Modern oil filters are designed to remove even the smallest particles from the oil, ensuring that the engine runs smoothly and efficiently. They are also built to withstand the harsh conditions inside the engine, ensuring long-lasting performance.

Industry Trends

Market Growth: The global oil filter market has been growing steadily, driven by the increasing demand for automobiles and the need for regular maintenance. As the number of vehicles on the road continues to rise, so does the demand for oil filters.

Innovation: Manufacturers are constantly innovating to improve the performance and efficiency of oil filters. This includes the development of new filtration technologies, such as nanofiber media, which can remove even smaller particles from the oil.

Environmental Concerns: With growing environmental concerns, manufacturers are also focusing on developing oil filters that are more eco-friendly. This includes the use of recyclable materials and the design of filters that can be easily disposed of or recycled.

Pressure relief valves

Most pressurized lubrication systems incorporate an overpressure relief valve to allow oil to bypass the filter if its flow restriction is excessive, to protect the engine from oil starvation. Filter bypass may occur if the filter is clogged or the oil is thickened by cold weather. The overpressure relief valve is frequently incorporated into the Fuel/Diesel Filter. Filters mounted such that oil tends to drain from them usually incorporate an anti-drainback valve to hold oil in the filter after the engine (or other lubrication system) is shut down. This is done to avoid a delay in oil pressure buildup once the system is restarted; without an anti-drainback valve, pressurized oil would have to fill the filter before travelling onward to the engine's working parts. This situation can cause premature wear of moving parts due to initial lack of oil.

Types of oil filter

Mechanical

Mechanical designs employ an element made of bulk material (such as cotton waste) or pleated Filter paper to entrap and sequester suspended contaminants. As material builds up on (or in) the filtration medium, oil flow is progressively restricted. This requires periodic replacement of the filter element (or the entire filter, if the element is not separately replaceable).

Cartridge and spin-on

Replacement paper filter element for a JCB

Early engine oil filters were of cartridge (or replaceable element) construction, in which a permanent housing contains a replaceable filter element or cartridge. The housing is mounted either directly on the engine or remotely with supply and return pipes connecting it to the engine. 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. This made filter changes more convenient and potentially less messy, and quickly came to be the dominant type of oil filter installed by the world's automakers. Conversion kits were offered for vehicles originally equipped with cartridge-type filters. In the 1990s, European and Asian automakers in particular began to shift back in favor of replaceable-element filter construction, because it generates less waste with each filter change. American automakers have likewise begun to shift to replaceable-cartridge filters, and retrofit kits to convert from spin-on to cartridge-type filters are offered for popular applications. Commercially available automotive oil filters vary in their design, materials, and construction details. 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. These variables affect the efficacy, durability, and cost of the filter.

Motorcycle oil filters on Kawasaki W175. Old (left) and new (right).

Magnetic

Magnetic filters use a permanent magnet or an electromagnet to capture ferromagnetic particles. An advantage of magnetic filtration is that maintaining the filter simply requires cleaning the particles from the surface of the magnet. Automatic transmissions in vehicles frequently have a magnet in the fluid pan to sequester magnetic particles and prolong the life of the media-type fluid filter. Some companies are manufacturing magnets that attach to the outside of an oil filter or magnetic drain plugs—first invented and offered for cars and motorcycles in the mid-1930s—to aid in capturing these metallic particles, though there is ongoing debate as to the effectiveness of such devices.

Sedimentation

A sedimentation or gravity bed filter allows contaminants heavier than oil to settle to the bottom of a container under the influence of gravity.

Centrifugal

A centrifuge oil cleaner is a rotary sedimentation device using centrifugal force rather than gravity to separate contaminants from the oil, in the same manner as any other centrifuge. 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. The oil then slides to the bottom of the housing wall, leaving particulate oil contaminants stuck to the housing walls. The housing must periodically be cleaned, or the particles will accumulate to such a thickness as to stop the drum rotating. In this condition, unfiltered oil will be recirculated. Advantages of the centrifuge are: (i) that the cleaned oil may separate from any water which, being heavier than oil, settles at the bottom and can be drained off (provided any water has not emulsified with the oil); and (ii) they are much less likely to become blocked than a conventional filter. If the oil pressure is insufficient to spin the centrifuge, it may instead by driven mechanically or electrically.

Note: some spin-off filters are described as centrifugal but they are not true centrifuges; rather, the oil is directed in such a way that there is a centrifugal swirl that helps contaminants stick to the outside of the filter.

High efficiency (HE)

High efficiency oil filters are a type of bypass filter that are claimed to allow extended oil drain intervals. HE oil filters typically have pore sizes of 3 micrometres, which studies have shown reduce engine wear. Some fleets have been able to increase their drain intervals up to 5-10 times.