Chapter 10: Final Review & Key Terms

1. Ready for Review

• The lubrication system reduces friction between moving parts in an engine and is essential for cooling, cleaning, sealing, and absorbing shock loads inside the engine.
• Lubrication systems in today’s diesels have new demands because of emissions legislation and durability requirements.
• Oil works by forming a separating film between parts, which minimizes direct contact between moving parts, reducing friction and heat buildup caused by friction.
• Oil may be derived from biological sources, but lubricating oils, even synthetics, are primarily a product of petroleum refined from crude oil.
• Engine oils are classified by the API and carry an API designation indicating their suitability for an engine application.
• Viscosity is a liquid’s resistance to flow; a numerical designation developed by the SAE is used to measure oil viscosity.
• Motor oils are typically 75–85% base stock, which is the raw mineral processed from crude oil. The remainder of the oil volume is chemical additives.
• Additives improve the original properties of the base stock oil; enhancing the performance of motor oil base stocks is necessary to adjust the performance of the oil to suit its intended application.
• Synthetic oils are oils with base stock that was synthetically derived or manufactured.
• For years, biodiesel has been considered a lubricity additive to keep moving parts operating smoothly inside fuel injection systems. However, the dilution of engine oil with biodiesel is another matter, as biodiesel promotes fuel dilution to a much greater extent than mineral diesel fuel.
• The lubrication system accomplishes its tasks as a function of a number of major lubrication system components, including pressure-regulating and pressure-relief valves, the oil pump, the oil pan, the oil cooler, and the oil filter(s).
• The function of the oil pan is to store an adequate supply of oil for the lubrication system.
• Oil pumps are used to pressurize the lubrication system of a diesel engine.
• The oil pump can produce more oil flow than the engine can use; an oil pressure-regulating valve is used to control oil pressure.
• Oil coolers are heat exchangers used to remove excess heat from engine oil.
• The purpose of lubrication oil filtration is contamination removal; oil contamination can cause abrasives to rapidly wear engine components if not properly controlled.
• Today’s diesel engine technology requires lubrication oils to meet a variety of operating conditions and provide for long service intervals and engine durability.
• The main factors that can limit oil life are the percentage of solids suspended in the oil, sulfur and combustion acids, and oxidized oil.
• Oil change intervals are based on the operating conditions an engine encounters and the amount of fuel consumed; as a general rule, every 45 gallons (170 L) of fuel consumed by the diesel engine produces enough contaminants to use up 1 quart (1 L) of oil.
• It is in the interest of owners and the environment to extend oil change intervals.
• Operation of the valves and oil pump is evaluated using a pressure gauge in the main oil gallery.