Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/793941
44 | March - April 2017 | www.machinerylubrication.com active and work in frictional zones. Simply put, they begin working at colder tempera- tures than traditional AW and EP additives and thus can further lower energy consumption. In engines, they also can help to decrease emissions. Detergents serve two purposes: to clean deposits from high heat areas and to neutralize acids formed in the combustion cycle. During combustion, byproducts often get past the rings in an engine and find their way into the oil. These byprod- ucts are referred to as blow-by. If left unchecked, blow-by will produce acids, which can result in shorter oil change inter- vals and poor lubrication. Detergents neutralize acids before they become a problem, thus extending the oil change interval and diminishing the risk of these acids causing further damage. As is the case with most additives, detergents are sacrificial and have limited lifespans. Typi- cally, once detergent levels drop by 50 percent, the oil must be changed. Dispersants are used to control soot deposits. Soot is a byproduct of combus- tion. Over time, soot can build up and lead to a rise in oil viscosity, impaired lubrica- tion, increased wear and shorter oil change intervals. Good dispersancy is key for optimum performance and maximum lifespan from an engine. Dispersants help to prevent soot from agglomerating and settling out of the oil. If soot stays finely divided and suspended throughout the oil, you have a much better chance of filtering it and preventing the associated deposits. This can keep valves and rings free to move, minimizing emissions and acid formation. Applications Possibly the most important applica- tion in which emissions can be controlled with proper lubrication is the internal combustion engine. These types of engines are responsible for a large number of emis- sions into the atmosphere, as most people drive to work or use their vehicle for their livelihood. When purchasing motor oils, you should concern yourself with what is known as the American Petroleum Insti- tute (API) service classification. This classification will tell you if the oil meets the standards put forth by the API in certain aspects, such as additive load, IN THE TRENCHES 7 6 5 4 3 2 1 0 0 50 100 150 200 250 300 350 400 450 500 Soot Load (% in Oil) Engine Hours Carbon Concentration Dependent Soot Load vs. Time High Soot Load (Causes Wear) Wear risk varies proportionally with soot load 0.04 0.1 0.2 0.4 0.6 0.8 1 2 4 Concentration Soot Cluster Size (Microns) Cluster Dependent Size High risk of surface deposits Good Dispersancy Poor Dispersancy Poor Soot Dispersancy (Causes Deposits) Soot Generation and Load Factors Dispersancy Disruption Factors • Combustion efficiency • EGR • Idling • Elevation • Makeup rate • Filtration • Fuel economy • Drain interval • High soot load • Water in oil • Antifreeze (glycol) in oil • Fuel in oil • Additive depletion