Machinery Lubrication magazine published by Noria Corporation
Issue link: http://www.e-digitaleditions.com/i/572212
" " www.machinerylubrication.com | September - October 2015 | 29 their quantities. In order to assess the measured values, you must know whether the individual elements indicate contamination, wear or changes to the additives. However, these values are also inter- related to a certain extent. The relative proportion of various wear elements provides an indication of the affected machine parts or components, for example. Further, it is important to know how long it has taken for the oil to become enriched with specific wear elements since the last oil change. The oper- ating time of the overall system or the running time of the engine, the oil volume relative to the engine power, and the top-up amounts must also be consid- ered when analyzing or diagnosing warning levels. In order to reliably assess the values determined for the used oil and their relationship to each other and to other factors, it is necessary to have a suit- ably large volume of data and analytical expertise. However, additive elements and base oil types can differ considerably depending on the type of oil used, so it is necessary to set suitably broad warning levels. Specific warning levels can only be defined for a specific oil type. The warning and limit levels listed in Tables 1-3 for wear elements, contaminants and additives are based on a semi-synthetic motor oil (SAE 10W-40) in a modern diesel engine with an oil volume of approximately 25 to 50 liters, using fuel compliant with EN 590 (containing 5 percent fatty acid methyl esters), and with an oil service life of approximately 500 operating hours or a mileage of approximately 47,000 miles. The basic rule is that warning levels must be set lower for greater oil volume, shorter oil service life, lower engine speed and lighter load conditions. However, the stated values are distinctly depen- dent on the oil manufacturer, the correct engine type, the service life of the oil charge, the oil volume and the top-up quantities (if any). ML ELEMENT UPPER WARNING LEVEL ORIGIN Calcium (Ca) 600–5,000 Oil additive, detergent oil additive; improves cleaning and dispersion capacity as well as heat resistance; occasionally calcium-containing dust from building sites, lubricating grease constituent, or from cooling water or tap water containing calcium Magnesium (Mg) 100–1,500 Oil additive; improves the corrosion protection, thermal stability and dispersion capacity of motor oils; increases the alkali reserve (BN); alloy constituent of engine blocks; hardening agent in hard tap water or salt water Boron (B) 10–500 Improves engine cleanliness as an oil additive; borates are constituents of cooler antifreeze and corrosion protection media Zinc (Zn) Up to 2,000 in fresh oil Improves wear protection as an oil additive; zinc-plated com- ponents such as filter support cores, threaded fittings, paints containing zinc and vulcanized synthetic materials Phosphorus (P) 600–2,000 Oil additive in almost all types of oil; used to improve EP charac- teristics and reduce wear; has an anti-corrosion and anti-bacterial effect; reduces friction; renders metal surfaces chemically inert Barium (Ba) 2–20 Usually not an additive in motor oils; for improving EP character- istics; friction modifier in ATFs; in the form of barium-complex soap; a constituent of greases and assembly pastes Sulfur (S) 500–6,000 Constituent of base oils based on mineral oil; for this reason, it is present in almost all oils, but in widely varying amounts; along with phosphorus, sulfur is also a constituent of almost all additive packages for wear and corrosion protection, and is often found in connection with calcium and zinc Table 3. Additives Warning levels must be set lower for greater oil volume, shorter oil service life, lower engine speed and lighter load conditions.