Since no engine is 100% efficient, products other than carbon dioxide and water will be formed during combustion. One such product produced from incomplete combustion is soot. Soot is a mass of mainly carbon particles that are typically spherical in shape. As soot levels rise, the soot particles begin to clump together and become more dangerous. The soot levels will continue to increase and the particles clump together until it reaches a level great enough to precipitate out of the oil. This precipitation will both increase the viscosity of the oil and attach itself to the engine surfaces which will significantly increase wear on the engine. This precipitation can also lead to filter plugging. Performing regular soot checks can realize cost savings by extending drain periods, reducing used oil disposal, and extending the life of diesel engines.
Guide for Measuring Fuel Dilution in Lubricating Oil
Fuel dilution in oil can cause serious engine damage. High levels of fuel (>2%) in a lubricant can result in decreased viscosity, oil degradation, loss of dispersancy, and loss of oxidation stability. Fuel dilution is one of the most important lubricant failure modes in internal combustion engines. It usually occurs due to improper fuel-to-air ratio. Fuel dilution can also occur due to excessive idling, piston ring wear, or defective injectors and loose connectors.
Measuring Oil Chemistry: Nitration, Oxidation, and Sulfation
An in-service lubricant encounters air, heat, pressure, corrosive agents, and other factors that cause chemical changes in the oil. A change in oil chemistry can affect the ability of the lubricant to do its job (for example if crucial additives have been depleted). Over time, these chemical reactions can result in build-up of harmful degradation by-products like weak organic acids. Oil chemistry analysis always includes oxidation and may also include nitration and sulfation depending on the application. In some cases, oils may also be tested to check for the depletion of specific additives, like a ZDDP antiwear package.
Evaluating the wear condition of equipment is a primary requirement of condition monitoring programs. Oil wetted equipment will generate wear particles throughout its lifetime, the nature and rate of the wear varies from initial break in through to end of life seizure. The technique employed to detect wear and its severity is spectroscopy. Spectroscopy is a technique for detecting and quantifying the presence of elements in a material. Spectroscopy utilizes the fact that each element has a unique atomic structure. When subjected to the addition of energy, each element emits light of specific wavelengths, or colors. Since no two elements have the same pattern of spectral lines, the elements can be differentiated. The intensity of the emitted light is proportional to the quantity of the element present in the sample allowing the concentration of that element to be determined. Typically these techniques get their names from the method used to excite the elements.