Overview
Challenges
Additives and Formulation
Used Lube Tests

In terms of deign, ICE can be two stroke or four stroke engine design

A two-stroke (or two-cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during only one crankshaft revolution. This is in contrast to a four-stroke engine, which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time.

Two-stroke engines use their crankcase to pressurize the air-fuel mixture before transfer to the cylinder. Unlike four-stroke enginess, they cannot be lubricated by oil contained in the crankcase and sump: lubricating oil would be swept up and burnt with the fuel. Fuels supplied to two-stroke engines are mixed with oil so that it can coat the cylinders and bearing surfaces along its path. The ratio of gas to oil ranges from 30:1 to 50:1 by volume.

Large two-stroke engines, including diesels, normally use a sump lubrication system similar to four-stroke engines. The cylinder must be pressurized, but this is not done from the crankcase, but by an ancillary Roots-type blower or a specialized turbocharger (usually a turbo-compressor system) which has a "locked" compressor for starting (and during which it is powered by the engine's crankshaft), but which is "unlocked" for running (and during which it is powered by the engine's exhaust gases flowing through the turbine).

In terms of fuel it can be liquid fuel Engines or gas fired engines

As the use of natural gas as a fuel source grows, an increasing number of stationary gas engines are being used to generate power and to move gas from the wellhead to the customer. Engine operators need to maximise the return on their investment, a demand that has led manufacturers to redesign their products. The changes have focused on increasing the engine’s efficiency and power output while reducing emissions such as NOx, methane and other volatile organic hydrocarbons.

Not only are the combustion temperatures and pressures higher, but also piston design changes put the top ring closer to the combustion zone. This means the lubricant here must handle higher temperatures, raising the concern of deposit formation, which may lead to ring sticking and engine damage.

Oil degradation

In high temperature gas engines, carbonaceous deposits occur in many different forms and locations – for example, ring-groove deposits and rocker cover sludge. It is essential for lubricants to either prevent deposits from forming or to stop them building up on engine surfaces.

However, despite these similarities the particles are not formed in the same way. Heavy-duty diesel (HDD) soot is formed from incomplete combustion of fuel, while in a lean burn gas engine operating on gas compromising primarily of methane, with a significant molar excess of oxygen, the level of incomplete combustion is likely to be negligible. It is much more likely that carbonaceous deposits in gas engines result from the incomplete combustion of lubricant present in the combustion chamber.

Comparison of gas engines and commercial vehicle soot

The main function of motor oil is to:

Provides Lubrication

by reducing friction and wear on moving parts

Cleans out Sludge

Clean the engine from sludge (one of the functions of dispersants) and varnish (detergents) to prevent blockage.

Neutralizes Acids

It also neutralizes acids that originate from fuel combustion and from oxidation of the lubricant (detergents),

Inhibits corrosion and oxidation

Another function of engine oil is preventing corrosion. Motor oil protects the cylinder blocks from rust.

Improves sealing of piston rings

Cools the engine by carrying heat away from moving parts

Types of Lubricant Additives

There are many types of chemical additives mixed into base oils to enhance the properties of the base oil, to suppress some undesirable properties of the base oil and possibly to impart some new properties.

Additives typically make up about 0.1 to 30 percent of the finished lubricating oil, depending upon the target application of the lubricant.

Conventional Lubricant Additives

These include the following general types of additives:

Anti-oxidants

Oxidation is the general attack of the weakest components of the base oil by oxygen in the air. It occurs at all temperatures all of the time but is accelerated at higher temperatures and by the presence of water, wear metals and other contaminants.

It ultimately causes acids (which produce corrosion) and sludge (which results in surface deposits and viscosity to increase) to form. Oxidation inhibitors, as they are also called, are used to extend the operating life of the oil.

They are sacrificial additives that are consumed while performing their duty of delaying the onset of oxidation, thus protecting the base oil. They are present in almost every lubricating oil and grease.

Rust and Corrosion Inhibitors

Rust Inhibitor

These additives reduce or eliminate internal rust and corrosion by neutralizing acids and forming a chemical protective barrier to repel moisture from metal surfaces.

Some of these inhibitors are specific to protecting certain metals. Therefore, an oil may contain several corrosion inhibitors. Again, they are common in almost every oil and grease. Metal deactivators are another form of corrosion inhibitor.

Viscosity Index Improvers

Viscosity index improvers are very large polymer additives that partially prevent the oil from thinning out (losing viscosity) as the temperature increases. These additives are used extensively when blending multi-grade engine oils such as SAE 5W-30 or SAE 15W-40.

They are also responsible for better oil flow at low temperatures, resulting in reduction in wear and improved fuel economy. In addition, VI improvers are used to achieve high-VI hydraulic and gear oils for improved start-up and lubrication at low temperatures.

To visualize how a VI-improver additive functions, think of the VI improver as an octopus or coil spring that stays coiled up in a ball at low temperatures and has very little effect on the oil viscosity.

Then, as the temperature rises, the additive (or octopus) expands or extends its arms (making it larger) and prevents the oil from thinning out too much at high temperatures.

VI improvers do have a couple of negative features. The additives are large (high molecular weight) polymers, which makes them susceptible to being chopped or cut up into small pieces by machine components (shearing forces). Gears are notoriously hard on VI-improver additives.

Permanent shearing of the VI-improver additive can cause significant viscosity losses, which can be detected with oil analysis. A second form of viscosity loss occurs due to high shearing forces in the load zone of frictional surfaces (e.g., in journal bearings).

It is thought that the VI-improver additive loses its shape or uniform orientation and therefore loses some of its thickening ability.

The viscosity of the oil temporarily drops within the load zone and then rebounds to its normal viscosity after it leaves the load zone. This characteristic actually aids in the reduction of fuel consumption.

There are several different types of VI improvers (olefin copolymers are common). High-quality VI improvers are less susceptible to permanent shear loss than low-cost, low-quality VI improvers.

Anti-wear (AW) Agents

These additives are typically used to protect machine parts from wear and loss of metal during boundary lubrication conditions. They are polar additives that attach to frictional metal surfaces.

They react chemically with the metal surfaces when metal-to-metal contact occurs in conditions of mixed and boundary lubrication.

They are activated by the heat of contact to form a film that minimizes wear. They also help protect the base oil from oxidation and the metal from damage by corrosive acids.

These additives become “used up” by performing their function, after which adhesive wear damage will increase. They are typically phosphorus compounds, with the most common being zinc dialkyldithiophosphate (ZDDP).

There are different versions of ZDDP — some intended for hydraulic applications and others for the higher temperatures encountered in engine oils. ZDDP also has some anti-oxidant and corrosion-inhibition properties. In addition, other types of phosphorous-based chemicals are used for anti-wear protection (e.g., TCP).

Extreme Pressure (EP) Additives

These additives are more chemically aggressive than AW additives. They react chemically with metal (iron) surfaces to form a sacrificial surface film that prevents the welding and seizure of opposing asperities caused by metal-to-metal contact (adhesive wear).

They are activated at high loads and by the high contact temperatures that are created. They are typically used in gear oils and give those oils that unique, strong sulphur smell. These additives usually contain sulphur and phosphorus compounds (and occasionally boron compounds).

They can be corrosive toward yellow metals, especially at higher temperatures, and therefore should not be used in worm gear and similar applications where copper-based metals are used. Some chlorine-based EP additives exist but are rarely used due to corrosion concerns.

Anti-wear additives and extreme pressure agents form a large group of chemical additives that carry out their function of protecting metal surfaces during boundary lubrication by forming a protective film or barrier on the wear surfaces.

As long as the hydrodynamic or elastohydrodynamic oil film is maintained between the metal surfaces, boundary lubrication will not occur and these boundary lubrication additives will not be required to perform their function.

When the oil film does break down and asperity contact is made under high loads or high temperatures, these boundary lubrication additives protect the wearing surfaces.

Detergents

Detergents perform two functions. They help to keep hot metal components free of deposits (clean) and neutralize acids that form in the oil. Detergents are primarily used in engine oils and are alkaline or basic in nature.

They form the basis of the reserve alkalinity of engine oils, which is referred to as the base number (BN). They are typically materials of calcium and magnesium chemistry. Barium-based detergents were used in the past but are rarely used now.

Since these metal compounds leave an ash deposit when the oil is burned, they may cause unwanted residue to form in high-temperature applications. Due to this ash concern, many OEMs are specifying low-ash oils for equipment operating at high temperatures. A detergent additive is normally used in conjunction with a dispersant additive.

Dispersants

Dispersants are mainly found in engine oil with detergents to help keep engines clean and free of deposits. The main function of dispersants is to keep particles of diesel engine soot finely dispersed or suspended in the oil (less than 1 micron in size).

The objective is to keep the contaminant suspended and not allow it to agglomerate in the oil so that it will minimize damage and can be carried out of the engine during an oil change. Dispersants are generally organic and ashless. As such, they are not easily detectable with conventional oil analysis.

The combination of detergent/dispersant additives allows more acid compounds to be neutralized and more contaminant particles to stay suspended. As these additives perform their functions of neutralizing acids and suspending contaminants, they will eventually exceed their capacity, which will necessitate an oil change.

Anti-foaming Agents

The chemicals in this additive group possess low interfacial tension, which weakens the oil bubble wall and allows the foam bubbles to burst more readily. They have an indirect effect on oxidation by reducing the amount of air-oil contact.

Some of these additives are oil-insoluble silicone materials that are not dissolved but rather dispersed finely in the lubricating oil. Very low concentrations are usually required. If too much anti-foaming additive is added, it can have a reverse effect and promote further foaming and air entrainment.

Friction Modifiers

Friction modifiers are typically used in engine oils and automatic transmission fluids to alter the friction between engine and transmission components. In engines, the emphasis is on lowering friction to improve fuel economy.

In transmissions, the focus is on improving the engagement of the clutch materials. Friction modifiers can be thought of as anti-wear additives for lower loads that are not activated by contact temperatures.

Pour Point Depressants

The pour point of an oil is approximately the lowest temperature at which an oil will remain fluid. Wax crystals that form in paraffinic mineral oils crystallize (become solid) at low temperatures. The solid crystals form a lattice network that inhibits the remaining liquid oil from flowing.

The additives in this group reduce the size of the wax crystals in the oil and their interaction with each other, allowing the oil to continue to flow at low temperatures.

Demulsifiers

Demulsifier additives prevent the formation of a stable oil-water mixture or an emulsion by changing the interfacial tension of the oil so that water will coalesce and separate more readily from the oil. This is an important characteristic for lubricants exposed to steam or water so that free water can settle out and be easily drained off at a reservoir.

Emulsifiers

Emulsifiers are used in oil-water-based metal-working fluids and fire-resistant fluids to help create a stable oil-water emulsion. The emulsifier additive can be thought of as a glue binding the oil and water together, because normally they would like to separate from each other due to interfacial tension and differences in specific gravity.

Biocides

Biocides are often added to water-based lubricants to control the growth of bacteria.

Tackifiers

Tackifiers are stringy materials used in some oils and greases to prevent the lubricant from flinging off the metal surface during rotational movement.

To be acceptable to blenders and end users alike, the additives must be capable of being handled in conventional blending equipment, stable in storage, free of offensive odor and be non‑toxic by normal industrial standards.

Since many are highly viscous materials, they are generally sold to the oil formulator as concentrated solutions in a base oil carrier.

A couple of key points about additives:
More additive is not always better. The old saying, “If a little bit of something is good, then more of the same is better,” is not necessarily true when using oil additives.

As more additive is blended into the oil, sometimes there isn’t any more benefit gained, and at times the performance actually deteriorates. In other cases, the performance of the additive doesn’t improve, but the duration of service does improve.

Increasing the percentage of a certain additive may improve one property of an oil while at the same time degrade another. When the specified concentrations of additives become unbalanced, overall oil quality can be affected.

Some additives compete with each other for the same space on a metal surface. If a high concentration of an anti-wear agent is added to the oil, the corrosion inhibitor may become less effective. The result may be an increase in corrosion-related problems.

How Oil Additives Get Depleted

It is very important to understand that most of these additives get consumed and depleted by:

“decomposition” or breakdown,
“adsorption” onto metal, particle and water surfaces, and
“separation” due to settling or filtration.

The adsorption and separation mechanisms involve mass transfer or physical movement of the additive.

For many additives, the longer the oil remains in service, the less effective the remaining additive package is in protecting the equipment.

When the additive package weakens, viscosity increases, sludge begins to form, corrosive acids start to attack bearings and metal surfaces, and/or wear begins to increase. If oils of low quality are used, the point at which these problems begin will occur much sooner.

It is for these reasons that top-quality lubricants meeting the correct industry specifications (e.g., API engine service classifications) should always be selected. The following table can be used as a guide for a more thorough understanding of additive types and their functions in engine oil formulations.

SURFACE PROTECTIVE ADDITIVES ENGINE LUBRICANTS
ADDITIVE TYPE	PURPOSE	TYPICAL COMPOUNDS	FUNCTIONS
Anti-Wear Agent	Reduce friction and wear, and prevent scoring and seizure	Zinc dithiophosphates, organic phosphates and acid phosphates; organic sulphur and chlorine compounds; sulphurized fats, sulfides and disulfides	Chemical reaction with the metal surface to form a film with lower shear strength than the metal, thereby preventing metal-to-metal contact
Corrosion & Rust Inhibitor	Prevent corrosion and rusting of metal parts in contact with the lubricant	Zinc dithiophosphates, metal phenolates, basic metal sulfonates, fatty acids and amines	Preferential adsorption of polar constituent on metal surface to provide a protective film and/or neutralization of corrosive acids
Detergent	Keep surfaces free of deposits and neutralize corrosive acids	Metallo-organic compounds of barium, calcium and magnesium phenolates, phosphates and sulfonates	Chemical reaction with sludge and varnish precursors to neutralize them and keep them soluble
Dispersant	Keep insoluble soot dispersed in the lubricant	Polymeric alkylthiophosphonates and alkylsuccinimides, organic complexes containing nitrogen compounds	Contaminants are bonded by polar attraction to dispersant molecules, prevented from agglomerating and kept in suspension due to solubility of dispersant
Friction Modifier	Alter coefficient of friction	Organic fatty acids and amines, lard oil, high molecular weight organic phosphorus and phosphoric acid esters	Preferential adsorption of surface-active materials
PERFORMANCE ADDITIVES ENGINE LUBRICANTS
Pour Point Depressant	Enable lubricant to flow at low temperatures	Alkylated naphthalene and phenolic polymers, polymethacrylates	Modify wax crystal formation to reduce interlocking
Seal Swell Agent	Swell elastomeric seals	Organic phosphates, aromatics, halogenated hydrocarbons	Chemical reaction with elastomer to cause slight swell
Viscosity Improver	Reduce the rate of viscosity change with temperature	Polymers and copolymers of methacrylates, butadiene olefins and alkylated styrenes	Polymers expand with increasing temperature to counteract oil thinning
LUBRICANT PROTECTIVE ADDITIVES ENGINE LUBRICANTS
Anti-Foaming	Prevent lubricant from forming a persistent foam	Silicone polymers and organic copolymers	Reduce surface tension to speed collapse of foam
Anti-Oxidant	Retard oxidative decomposition	Zinc dithiophosphates, hindered phenols, aromatic amines, sulphurized phenols	Decompose peroxides and terminate free-radical reactions
Metal Deactivator	Reduce catalytic effect of metals on oxidation rate	Organic complexes containing nitrogen or sulphur, amines, sulphides and phosphites	Form inactive film on metal surfaces by complexing with metallic ions

Typical Tests

Wear

elemental wear, additives and contaminants

Ferrous wear - Ferrous wear measurement is a critical requirement for monitoring machine condition. The high sensitivity magnetometer measures and reports ferrous content in ppm/ml, and provides ferrous particle count and size distribution for large ferrous particles.

Chemistry

Total BASE Number (TBN) - TBN is measured to determine the corrosive potential of lubrication oils. If the TAN gets too high the oil can induce corrosion of machine parts and should be changed.

Total BASE Number (TAN) - TAN is measured to determine the corrosive potential of lubrication oils. If the TAN gets too high the oil can induce corrosion of machine parts and should be changed.

Viscosity and Viscosity Index - The main function of lubrication oil is to create and maintain a lubrication film between two moving metal surfaces. Insuring the viscosity is within recommended ranges is one of the most important tests one can run on lube oil.

Contamination

Water - Water contamination in industrial oils can cause severe issues with machinery components. The presence of water can alter the viscosity of a lubricant as well as cause chemical changes resulting in additive depletion and the formation of acids, sludge, and varnish.

coollant contamination

combustion by products " sulfation nitration soot

OXidation

Fuel Dilution

Overview
Challenges
Additives and Formulation
Used Lube Tests

4 Main Types of Industrial Gearbox

An industrial gearbox is an enclosed system that transmits mechanical energy to an output device, for an example a motor. A gearbox can be used to modify the ratio of speed, torque and rate of rotation sent to the output device. Gearboxes have a wide range of applications and come in 4 main varieties.

Planetary Gearbox

This type of Gearbox is popular in cutting edge technologies like Robotics and 3D printing. A Planetary Gearbox has a central Sun Gear is surrounded by three of four Planet Gears. These are all held together through an outer ring gear with internal teeth. This design spreads the power equally through the gears and enables a Planetary Gear System to achieve a high torque in a small space. Planetary Gear Boxes are known for their high endurance and accuracy.

Worm Gearbox

Worm Gearboxes are most often used to drive heavy duty operations. This type of gear incorporates a large diameter worm (or screw) which meshes with the teeth on the peripheral area of the gear. This arrangement allows the user to determine rotational speed and allows a higher torque to be transmitted. Worm gears are used to transmit power at 90 degrees and applications include elevators and conveyor belts.

Helical Gearbox

Helical Gearboxes are compact in size and use a low amount of power. The teeth on a Helical Gear are cut to an angle to the face of the gear and so during rotation, when two of the teeth start to engage the contact is gradual. Starting at one end of the tooth and maintaining contact as the gear rotates into full engagement. This arrangement means the gearbox will run more smoothly and can accommodate high load angles. It also means that a Helical Gearbox can transmit motion between parallel or right angles shafts.

Bevel Gearbox

Bevel Gears have curbed teeth located on cone shaped surfaces which close to the rim of the unit. They are used to provide rotary motions between non-parallel shafts and have a wide range of applications including in Rolling Stock and the mining industry.

Gear pump[edit]

Gear pump

This is the simplest form of rotary positive-displacement pumps. It consists of two meshed gears that rotate in a closely fitted casing. The tooth spaces trap fluid and force it around the outer periphery. The fluid does not travel back on the meshed part, because the teeth mesh closely in the center. Gear pumps see wide use in car engine oil pumps and in various hydraulic power packs.

Screw pump[edit]

Screw pump

A screw pump is a more complicated type of rotary pump that uses two or three screws with opposing thread — e.g., one screw turns clockwise and the other counterclockwise. The screws are mounted on parallel shafts that have gears that mesh so the shafts turn together and everything stays in place. The screws turn on the shafts and drive fluid through the pump. As with other forms of rotary pumps, the clearance between moving parts and the pump's casing is minimal.

Progressing cavity pump[edit]

Widely used for pumping difficult materials, such as sewage sludge contaminated with large particles, this pump consists of a helical rotor, about ten times as long as its width. This can be visualized as a central core of diameter x with, typically, a curved spiral wound around of thickness half x, though in reality it is manufactured in a single casting. This shaft fits inside a heavy-duty rubber sleeve, of wall thickness also typically x. As the shaft rotates, the rotor gradually forces fluid up the rubber sleeve. Such pumps can develop very high pressure at low volumes.

Roots-type pumps[edit]

A Roots lobe pump

Named after the Roots brothers who invented it, this lobe pump displaces the liquid trapped between two long helical rotors, each fitted into the other when perpendicular at 90°, rotating inside a triangular shaped sealing line configuration, both at the point of suction and at the point of discharge. This design produces a continuous flow with equal volume and no vortex. It can work at low pulsation rates, and offers gentle performance that some applications require.

Applications include:

High capacity industrial air compressors.
Roots superchargers on internal combustion engines.
A brand of civil defense siren, the Federal Signal Corporation's Thunderbolt.

Peristaltic pump[edit]

360° Peristaltic Pump

A peristaltic pump is a type of positive-displacement pump. It contains fluid within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made). A number of rollers, shoes, or wipers attached to a rotor compresses the flexible tube. As the rotor turns, the part of the tube under compression closes (or occludes), forcing the fluid through the tube. Additionally, when the tube opens to its natural state after the passing of the cam it draws (restitution) fluid into the pump. This process is called peristalsis and is used in many biological systems such as the gastrointestinal tract.

Plunger pumps[edit]

Plunger pumps are reciprocating positive-displacement pumps.

These consist of a cylinder with a reciprocating plunger. The suction and discharge valves are mounted in the head of the cylinder. In the suction stroke, the plunger retracts and the suction valves open causing suction of fluid into the cylinder. In the forward stroke, the plunger pushes the liquid out of the discharge valve. Efficiency and common problems: With only one cylinder in plunger pumps, the fluid flow varies between maximum flow when the plunger moves through the middle positions, and zero flow when the plunger is at the end positions. A lot of energy is wasted when the fluid is accelerated in the piping system. Vibration and water hammer may be a serious problem. In general, the problems are compensated for by using two or more cylinders not working in phase with each other.

Types[edit]

The main and important types of gas compressors are illustrated and discussed below:

Gearboxes, differentials, final drives and planetaries should be closely monitored for dirt and water contamination, although the type of wear occurring is usually the biggest concern.

Cooling, controlling contamination, reducing friction, and creating fluid seals are just a few of the many important responsibilities the lubricant serves. The chosen lubricant must fill all of these roles effectively and efficiently to promote healthy and long equipment life

Transmission fluid acts as a lubricant and as a cooling agent for all moving parts of the transmission. It is the lifeblood of the transmission and regular checks and changes are vital to the transmission system.

ATF exposed to the high heat generated by automatic transmissions tend to degenerate and break down becoming inefficient.

Seal Concerns

Mechanical seals are often integral parts of a component or system. If they are not considered when changes are made to the system, leaks, failure or downtime may occur.

Contamination, both from external and internal sources, is a significant issue with seals. Among the parameters associated with contamination to trend in your oil analysis reports would be the particle count number and the ISO cleanliness code. If your sample results return with continual increases in the particle count and low levels of ferrous material, this may lead to seal damage.

Viscosity is a critical property of any lubricant, yet it often is overlooked with gearbox seals. This parameter is important because the oil must be thick enough to maintain the proper film thickness between the two surfaces but thin enough to flow between the mating gear tooth surfaces. If the viscosity falls out of the specified range, internal contamination due to gear wear is likely. As noted above, this type of contamination can result in seal degradation.

Keep in mind that surface roughness, gear geometry and mating surface materials will also play a role in the life of the seals. However, these constraints are more difficult to manipulate than sustaining lubricant limits.

Although compatibility typically is only an issue when switching lubricants, it is another concern for seal life. Changing the base oil from mineral to synthetic while altering the additive packages that make up the lubricant can have a dramatic effect on the seals. When changing lubricants, consider not only the compatibility between the two lubricants but also how the new lubricant will react with the seal material. Swelling, erosion, blistering, depolymerization and excessive wear are all possible failure mechanisms when seals and lubricants do not function in a cohesive environment.

Foaming is a common problem with oil-lubricated components.

Foam is a collection of small bubbles of air that accumulate on or near the surface of the fluid. In severe cases, the foam can leak out of the machine through breathers, sight glasses and dipsticks. Foam is an efficient thermal insulator, so the temperature of the oil can become difficult to control. The presence of air bubbles in the fluid can lead to excessive oxidation, cavitation, the reduction of lubricating properties of the oil and hydraulic system failure.

Causes

The causes of foaming are many. The most common include:

Water contamination
Solids contamination
Depleted defoamant (possibly due to the use of excessively fine filtration and electrostatic separation technologies)
Mechanical issues (causing excessive aeration of the fluid)
Overfilling of the sump with splash- and bath-lubricated compartments
Cross contamination of the fluid with the wrong lubricant
Contamination of the fluid with grease
Too much defoamant additive, either by incorrect formulation or by incorrect reconstruction (sweetening) of the additive package

Types of Lubricant Additives

There are many types of chemical additives mixed into base oils to enhance the properties of the base oil, to suppress some undesirable properties of the base oil and possibly to impart some new properties.

Additives typically make up about 0.1 to 30 percent of the finished lubricating oil, depending upon the target application of the lubricant.