Page 109 - ingenioren

Technical Reference

Where Contamination Comes From allows airborne particles to enter. Removing air filters,
There are surprising number of different sources of opening oil caps, fuel tank caps and removal of oil
system contamination in engine filtration. and fuel filters are all possible sources for introducing
contamination to an engine. Keep your system
New Fluids closed as much as possible and take care to be sure
Adding new fluid can be a source; even though it’s everything that goes into the engine is as clean as
fresh from the drum, new engine oil isn’t clean. possible. One common example is very often funnels
(It may look clean, but, remember, the human eye are used fill the engine with oil. The oily funnel will
can only see a particle the size of about 40 μm.) collect dirt between uses. The funnel should be
Also, diesel fuel cleanliness varies from gas pump properly cleaned before using it to fill the engine with
to gas pump. Typical fuel cleanliness levels coming oil.
out of the pump are ISO rated at 22/21/18. (ISO
cleanliness code of 22/21/18 translates to a particle In-Operation
count of 20,000 to 40,000 per milliliter for particles The major sources of contamination in the engine are
of 4 µm and greater; 10,000 to 20,000 per milliliter the combustion by-products (soot) and oxidation of
for particles of 6 µm and greater; and 1300 to 2500 the fluids in the engine due to the thermal stressing.
per milliliter for particles of 14 µm and greater), and Wear-generated contaminants are a hazard during
water content is typically 200 to 300 ppm. Never
assume your fluids are clean until it has been Load
filtered.
Built-In Motion

Built-in contamination, also called primary
contamination, is caused during the manufacture,
assembly and testing of the engine and its Flow Dynamic
components. Metal filings, small burrs, dirt or Clearance
sand and other contaminants are routinely found (µm)
in initial clean up filtration of newly manufactured
engines.

Ingressed Chip/Grit ENGINE LIQUID FILTRATION - TECHNICAL REFERENCE
too large to
Ingressed or external contamination comes from enter clearance Clearance Size Particles
the environment surrounding the engine or vehicle. interact with surfaces to cause abrasive wear
Dirt can enter the engine fluid supply through crank
case breathers or fuel tank breathers and vents engine operation. The circuit actually generates
and the air intake system. Ingressed moisture, additional particles as the fluid comes into contact
particularly, can cause longer term problems. As with the precision machined surfaces of cyclinder
a hot system cools at night, cool moisture-laden walls and pistons, injector needles and pistons and
air can be drawn into the engine or fuel tank; crankshaft bearings. Contaminant levels can keep
as the air condenses, water is released into the doubling with every new particle generated. The result
engine or fuel tank. Water in excess of 0.5% by can be catastrophic if these contaminants are not
volume in a hydrocarbon-based fluid accelerates properly filtered out of the system.
the formation of acids, sludge and oxidation that
can attack internal components, cause rust, and Rubber & Elastomers
adversely affect lubrication properties. The severity Due to temperature, time, and high-velocity fluid
of ingression and type of contaminant are dictated streams, rubber compounds and elastomers
by the applications and environment. degrade—thus releasing particulates into the fluid.
Induced Biodiesels

Maintenance procedures can introduce Biodiesles can support biological growth and
contamination into the engine. Opening the engine generate organic contamination and microbes.

www.donaldson.com Engine Liquid Filtration • 107