Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/793941
www.machinerylubrication.com | March - April 2017 | 45 performance, emissions and fuel efficiency. For gasoline engines, the service classification begins with an "S," such as in "SN," which is the current classification. For diesel engines, the service classification starts with a "C," with the most current being "CK-4." There are formulation differences between the classifications, so it is best to know what your specific engine calls for when purchasing oil for your vehicle. Another classification found on most engine oils specifically relates to fuel efficiency. On the bottom of the API donut symbol, look for the words "energy conserving" or "resource conserving." When you see these terms, it means this particular oil has passed the ASTM fuel economy test. In this test, oil is introduced to a test engine in which fuel economy is measured. For SAE grades 0W-20 and 5W-20, the candidate oil must show an increase in fuel economy of 2.6 percent after 16 hours of testing and 1.2 percent after 100 hours. For 0W-30 and 5W-30 grades, the candidate oil must show an increase in fuel economy of 1.9 percent after 16 hours and 0.9 percent after 100 hours. The current trend in the automotive industry is to increase fuel economy as much as possible with the use of lighter viscosity grades, better base oils and additive properties that correspond to the engine's needs. Perhaps the biggest issue plaguing vehicles when it comes to emissions is the formation of nitrogen oxides (NOx). When fuel combusts in an engine with the presence of air, it forms NOx. This is then pushed out the tailpipe and into the atmosphere. There are several problems associated with this, such as a higher potential for acid rain and health risks if the compound is breathed in regularly. To combat this, many diesel engine manufacturers have gone to exhaust gas recirculation (EGR) systems. EGR systems employ the engine oil to further scrub harmful contami- nants from the exhaust gases. While this is good for the environment, it can cause trouble for the engine and the engine oil if not properly managed and monitored. EGR systems work by returning some of the exhaust gases back to the engine's intake side. During this time, the gases are cooled, which decreases the flame temperature in the combustion chamber. If the flame temperature is lowered, it helps to reduce the formation of NOx, which is better for the environment. The problem with EGR systems is the excess soot generated due to the recycling of exhaust gas. Since soot impairs a lubricant's health and increases the risk of engine wear, it is imperative that engines using an EGR system have condition-based oil changes. I've already discussed how additives can combat soot and wear, but as the soot load increases, it causes the additives in the oil to be used up faster, which results in shorter oil change intervals and a higher risk of failure. In these applica- tions, dispersancy testing is a must. Although most of this article has focused on engine oils, the same principles can be applied to other applications as well. Compressor systems are another type of equipment that benefits from selecting the proper base oil and additives for better handling of the gases present in the compression chamber and keeping them from being released into the atmosphere. In most refineries and petrochemical plants, compressors are utilized to recycle gases back into the process to be further refined. This cuts down on the venting of gases or flaring (burning off ), which leads to environmental pollution. A lways keep in mind that by properly matching the needs of your equipment to the properties of the lubricant, you not only can extend the life of your machinery, but you can also help protect the environment in which we live. About the Author Wes Cash is the director of technical services for Noria Corporation. He serves as a senior technical consultant for Lubrication Program Development projects and as a senior instructor for Noria's Oil Analysis I and Machinery Lubrication I and II training courses. Wes holds a Machine Lubrication Technician (MLT) Level II certification and a Machine Lubricant Analyst (MLA) Level III certification through the International Council for Machinery Lubrication (ICML). Contact Wes at wcash@noria.com to learn how Noria can help you select the right lubricants for your applications . ML 60% of lubrication professionals consider environmental concerns when selecting a lubricant for their equipment, based on a recent survey at MachineryLubrication.com