ENGINE LUBRICATION BASICS

Pinaki Roy

Engine Lubrication –What’s that?

• Lubrication, like in all moving parts, plays a key role in the life expectancy of an engine.

• Without oil, an engine would succumb to overheating and seizing very quickly.

• Lubricants help mitigate this problem and if properly monitored and maintained, can extend the life of an ENGINE!

• Lets try to understand it a bit more.

Where Does Engine Lubrication Begin

• The process of lubrication in an internal combustion engine begins in the sump, commonly referred to as the oil pan.

• From here, the oil is pulled through a strainer, by the oil pump, removing larger contaminants from the mass of the fluid.

• The oil then goes through the oil filter.

Understanding the Oil Filter

• An oil filter is designed to remove contaminants from the engine oil.

• Filters are designed differently as not all filters perform the same.

• A filter’s ability to remove particles is dependent upon many factors, including the media material (pore size, surface area and depth of filter), the differential pressure across the media and the flow rate across the media.

Where Does the Oil Go?

• The engine oil after passing through the filters goes through passageways to the various components of the engine such as the cam, main bearings, rod, pistons, etc.

• Gravity then pulls the oil back down to the bottom of the motor to drain back into the sump, and the cycle repeats.

Engine Oil Formulation• To appreciate the full impact of the engine

lubrication process, it is important to understand how oils are formulated.

• All engine oils have two components: additives and base oil. The total volume of additives in motor oil can range from 20 to 30 percent, depending on brand, formulation and application.

• These additives can enhance, suppress or add properties to the base oil.

Understanding Additives• A typical additive found in an engine oil would

include a detergent and a dispersant. These two work together to help rid the engine system of deposits caused by the burning of fuel and by the blow-by gases.

• Dispersants and detergents are small particles that have a polar head and an oleophilic tail. The polar heads are attracted to contaminants within the oil and surround them, forming a structure called a micelle.

What is Soot?• Soot is a good example of a deposit that is controlled by

detergents and dispersants. • Soot particles are enveloped by dispersant particles,

forming a micelle, and are kept from attaching to metal surfaces. They are moved in this state through the oil system until they are removed by the filter.

• This also prevents a process known as congealing. During congealing, soot particles begin to stack upon each other or congeal into a larger particle. Smaller soot particles that could pass through components without interrupting the fluid film can congeal to make larger particles, which may disrupt the film and damage surfaces.

Multi-grade Oils• Most vehicle engines use some form of multi-grade oil. This

types of oil have an additive called a viscosity -index (VI) improver. A common example would be 10W-30, 5W-40 or 15W-40.

• These VI improvers are long-chain organic molecules that change shape as the temperature of their environment changes. For example, in cold environments (engine startup), these molecules are tightly bound. As the oil heats up, they begin to stretch out. This allows the oil to flow more readily at colder temperatures but still maintain an acceptable viscosity and, more importantly, a lubricating layer in the operating temperature range.

Other Additives

• Another common additive has an anti-wear (AW) property. AW additives have particles that are shaped similar to detergents and dispersants, but the polar heads of these molecules are attracted to metal surfaces.

• Once attached to a metal surface, AW additives form a sacrificial layer that protects the surfaces beneath them from degradation under boundary conditions.

• Zinc di-alkyldi-thiophosphate (ZDDP) is a common form of this additive.

Engine Oil Failures• Engine oils are subject to several types of failures. • Contamination poses a major problem within engines. • Environmental contaminants can expedite the process of

oxidation and cause premature filter plugging. • Fuel contamination can lower the viscosity of the oil, leading

to boundary conditions within the engine’s moving parts. • Antifreeze contamination does the opposite, increasing

viscosity so the oil doesn’t flow as well into places that require thinner oil.

• Overheating and long drain intervals can also hasten the degradation of the oil and result in oxidation and poor lubricity.

More Failures…

• Besides the above, shearing of the contained additives can also create engine lubrication problems.

• This is because over a period of time, VI improvers are sheared down thereby reducing the oil’s viscosity at operating temperatures.

• Anti-Wear and dispersants/detergents also become depleted and the remaining molecules are not as effective.

• Failures can also be caused by extended drain intervals and poor maintenance.

• An oil change then becomes imperative.

Summing Up…• Always remember that in cases of engines, the

same basic principles of lubrication apply.• The lubricating film must be maintained to

ensure proper operating conditions and to achieve the maximum life of the engine’s components.

• Changing oil regularly and sustaining appropriate fluid levels are the keys to overall engine health and lifespan.

Tips to Improve the Efficiency of your Vehicle & Save up to 50%

• Regular maintenance as prescribed by the vehicle's manual will help the vehicle achieve its best fuel economy.

• Some overlooked maintenance items, such as a dirty & clogged filters and under-inflated tires, can increase fuel cost up to 13%.

• When replacing tires, replace them with the same make and model as the original tires when the vehicle was purchased.

• A study has estimated that if all Californians properly inflated and aligned their tires, it would save 300 million gallons of gasoline a year!

Happy Driving