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The Importance of Lube Filtration

Oil is the Lifeblood of an Engine. So, Protect Your Engine by Integrating Donaldson Filtration Solutions into Your Design.

Let’s get straight to the point – an engine needs lubricant. Without oil, an engine is just a hunk of useless metal with no moving parts. Oil passages run to virtually every moving component of the engine to maintain continuous lubrication and reduce friction between surfaces. Lubrication systems also play a vital role in cooling engine parts by dissipating heat, which is generated by friction and combustion during engine operation.

Due to advancing technology and the need for greater efficiency, engine systems now use precision-fit components to deliver greater energy output from combustion. But a more precise engine also requires a more precise lubrication system that can handle challenges like contaminants and temporarily reduced oil flow.

Contamination Challenges for Lube Systems

Contaminants inevitably breach an engine thanks to heat, friction and combustion. Engine-generated contaminants can include wear particles (metal) or combustion byproducts (carbonaceous-style contaminants). Oil byproducts can also be introduced from partially combusted fuel that ends up in oil, leading to degradation. This inhibits the ability of engine oil to do its job of lubrication and cooling.

Contaminants can also be introduced from the external environment, including from the oil itself (new oil is not always clean oil), by evading the air filters, via an open crankcase (depending on the engine configuration), from leaks in seals, or during the oil and filter change processes.

Oil Filters Are Engine Guardians

Oil filtration is a critical component of a lubrication system – it ensures that the oil can do its job effectively. Oil filters also extend the life of the oil, which reduces maintenance and materials cost. Every oil filter needs to effectively balance three key characteristics: efficiency (contaminant capture), capacity (contaminant holding) and restriction (resistance to flow). Lube systems need to be designed to optimize performance, and filters need to incorporate the latest technology in order to extend oil life and drain intervals.

In addition to capturing and retaining contaminants that build up over time, oil filtration systems are the last line of defense in protecting engine components from a disastrous chain reaction caused by metal fragments or large chunks of debris that may make it into the oil. Without an oil filter in place, this debris (if present) would have free reign to cause catastrophic failure across multiple engine systems.

Oil also cools engines by taking heat out of the piston. Lubrication systems play a vital role in cooling the engine parts by dissipating heat, which is generated by friction and combustion during engine operation. If you lose oil distribution to any of the key components, an engine will seize very rapidly. There are jets that continually spray the walls of the piston to keep the piston and the bore surfaces lubricated – and cool.

Longer Filter Life with Synthetic Media

To help extend service intervals, synthetic lubricant use has increased because it does not break down as quickly and has a longer life than traditional lubricant. As a result, there has also been an increased demand for filters that last longer to match the extended life of synthetic lubricants. In response, leading filter manufacturers like Donaldson often recommended synthetic media instead of cellulose media. Synthetic media helps balance the requirements for pressure drop and efficiency while delivering longer filter life.

Bypassing the Filter Is Fine, Temporarily

Lubrication systems will encounter times when oil flow is reduced or even cut off due to high restriction (oil filter plugging) or high oil viscosity (cold oil during start-up.) To address this issue, all oil circuits include a filtration bypass or pressure relief valve. The principle that drives the need for a bypass is that “dirty oil is better than no oil.” Allowing oil to bypass the filter media (usually temporarily) is much better than asking systems to function without any lubrication, which can quickly cause an engine to seize.

By-pass can be accomplished one of two ways:

  1. A by-pass valve included inside the filter that allows oil to flow past the valve (unfiltered) if restriction rises to a predetermined level. These systems usually include a sealing disk or a spring.
  2. A separate on-engine by-pass that allows for cold flow of oil. This method removes the filter from the flow until the system warms up, viscosity increases and restriction decreases. The bypass valve then closes, so that oil can pass through the filtration system, as intended.

Please note, filter bypass during cold starts or obstruction is NOT to be confused with including a finer level of filtration/contaminant removal achieved with the use of an auxiliary bypass (secondary) filter.

OEMs need to design and build engine lube systems that effectively manage engine lubrication and cooling needs while simultaneously extending the life of oils and filters in order to reduce maintenance costs for end-users. Thankfully, Donaldson can help with that.

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