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What characteristics do diesel generator lubricants need to have in order to meet the lubrication requirements of the unit?
July 05, 2022
In the diesel generator operation will have a lot of mutual friction movement of the metal surface, fast movement, and poor environment, and the temperature can reach 400 ℃ to 600 ℃, in such a situation, only the use of qualified lubricating oil can reduce the friction resistance of the friction parts, reduce the wear and tear of the machine parts, and partly cool the friction parts, clean the friction surface, and extend the service life.
Lubricating oil is a substance that is essential to support the normal operation of diesel generator sets, and it is used to reduce the wear and tear between the parts of the set by acting between two relative moving parts, and it also has the functions of auxiliary cooling and cooling, sealing and leakage prevention, rust and corrosion prevention, shock absorption and buffering. We know that when the diesel generator is running, there will be a lot of mutual friction movement of the metal surface, the movement speed is fast, the environment is poor, and the temperature can reach 400℃ to 600℃, in such a case, only the use of qualified lubricating oil can reduce the friction resistance of the friction parts, reduce the wear of the machine parts, and partly cool the friction parts, clean the friction surface, and extend the service life. Then diesel generator set lubricant need to have what characteristics to meet the unit lubrication requirements?
The viscosity of lubricating oil is the fluidity or consistency of the oil at a certain temperature. Viscosity is the resistance to flow. Viscosity is measured by a general-purpose viscometer called a cyberport. The most commonly used temperatures are 0° F, 150° F and 210° F. The oil sample flows from the viscometer into the receiving long-neck bottle, a process that is completed at a certain temperature. The time required for the oil sample to drain completely is recorded in s (seconds). Viscosity at a special temperature, read out by the Saipot general viscosity seconds.
The lower the temperature of the oil, the worse its fluidity; the hotter the oil, the thinner it is, the better the fluidity. Viscosity index is used to express the oil viscosity at different temperatures. Viscosity index is the scale of oil viscosity change at a given temperature. Chemicals are added to the oil so that the viscosity does not change much as the temperature of the oil changes. Usually the higher the viscosity index, the smaller the relative change in viscosity with temperature.
3. Freezing Point
In order to be easy to use, the oil must flow like a liquid. Cold conditions will increase the viscosity of the oil until it does not flow. The temperature at which the oil stops flowing is defined as the freezing point. As the oil approaches the freezing point, it becomes thick and difficult to pump out. To control the freezing point, additives are added to the oil.
Antioxidants reduce the effect of oxygen on the engine oil. The reduction of oxygen reduces the formation of sludge and carbon deposits in the engine. As mentioned earlier, any oxygen in the crankcase increases the oxidation of the oil in the engine, which produces acids. During the refining process, chemicals are added to the oil to help eliminate or absorb oxygen. If the oxygen is absorbed away, very little oil oxidation is produced and thus, very little acid is produced. Note: If the oil is not changed regularly, oxidation will increase.
5. Cleaners and dispersants
Cleaners are added to the oil to help clean particles, dirt, grime and other foreign matter from the engine. The detergents in the oil loosen and break down deposits of carbon, gum and dirt. These particles are suspended in the oil, a property known as suspension capacity. The oil then carries these loose materials to the oil filter. Particles smaller than the filter size remain in the oil until the oil is changed, and detergents also increase engine wear to some degree.
Dispersants are also added to the oil. Chemicals are added to the oil to keep small particles of contaminants dispersed or separated from each other. Without dispersants, particles tend to concentrate and form large particles. These heavy particles are difficult to suspend in the oil and can clog the oil passages and filters, and the impurity particles remain suspended until they eventually pass through the oil filter. At this point, the impurities and ash particles are removed by the filter. Dispersants greatly increase the amount of contaminants that the oil can carry, thus ensuring that it can continue to be used properly. Impurities in the oil are removed by the oil filter, then they are not deposited on the engine parts.
6. High friction resistant motor oil
In order to improve fuel consumption, people can reduce fuel consumption by using energy efficient motor oil. Energy efficient oils incorporate various additives that are used to reduce friction. If friction is reduced, the amount of frictional work consumed in the engine is reduced. The end result is an increase in the effective work done by the fuel. There are two types of energy efficient (EC) motor oils: ECI and ECII. ECI motor oils increase fuel economy by approximately 1.5% and ECII motor oils increase fuel economy by approximately 2.7%. Energy efficient oils can be identified by the ECI or ECII wording on the container.
7. Other additives
Anti-foam additives are added to the oil to reduce oil foaming. During normal operation, the oil is pressurized and pumped through the engine and the constant pumping causes the oil to foam. Any foam generated in the engine reduces lubrication, sealing, cooling and cleaning. Hydraulic valve tappets can also work poorly when the oil is foaming. Therefore, chemicals are added to the oil to reduce foam. Preservatives and rust inhibitors are added to the oil to reduce or stop corrosion of engine components. Chemicals are added to help neutralize the acids produced. Rust inhibitors are also used to help remove water vapor from engine components so that the oil adheres properly to engine components. Anti-scratch additives are added to the oil to help polish moving parts. This is especially important during the break-in period of a new engine.
Extreme pressure resistance additives are added to the oil to keep the oil molecules from separating from each other under high pressure. During operation, the oil is constantly being pressurized, squeezed, etc. This can cause the oil molecules to separate and reduce the lubricating properties of the oil. The added chemicals react with the metal surface to form a very strong, smooth film that is only as thick as a molecule. Using these additives, protection is added at the moment of extreme pressure (EP).
With the above characteristics, the lubricant will be able to greatly ensure the normal smooth operation of the diesel generator set. The oil will not lose too much under normal circumstances, but it is easily contaminated, thus promoting the role of protecting the diesel generator, so users should pay attention to regular replacement.
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