PRIN. OF INTERNAL COMBUSTION ENGINES - OD1619 LESSON 2/TASK 2
breather pipe, mixes with the oil, and when forced into the bearings, greatly
accelerates wear.
Water, one of the products of combustion, will seep by the
piston rings as steam and condense in the crankcase.
The water in the crankcase
then will emulsify with the oil to form a thick sludge.
Products of fuel
combustion will mix with the oil as they enter the crankcase through blowby. The
oil, when mixed with the contaminants, loses its lubricating qualities and becomes
acidic. Engine oil must be changed periodically to prevent contaminated oil from
allowing excessive wear and causing etching of bearings.
Oil contamination is
controlled in the following ways:
FIGURE 49.
HOW OIL LUBRICATES.
(a) Control engine temperature; a hotter running engine burns its fuel more
completely and evaporates the water produced within it before any appreciable oil
contamination occurs.
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