Like any vehicle fleet manager, you want to avoid high engine maintenance and replacement part costs. Ensuring minimum wear and tear on engine components is crucial to improving fuel efficiency, lowering emissions, and reducing maintenance costs. Yet a decade after the ultra-low sulfur diesel (ULSD) regulations were ushered in, some engines are under stress from not using the best lubricity additive for engine oil.
The stress on your engine parts could be caused by the wrong type or mix of lubricants.
Lubricity Additive for Engine Oil
Ultra-low sulfur diesel (ULSD) standards have reduced vehicle emissions by 90 percent by lowering allowable emissions to under 15 parts per million. In addition to producing high pollutant emissions, sulfur is harsh on advanced emissions engine control and after-treatment technology.
Desulfurization, however, reduces the lubricity of diesel fuel. A lack of lubricity can cause even more damage to fuel system components. In low sulfur fuels, engine oil lubricity additives keep the moving parts in the fuel injection system lubricated. Benefits include:
Up to Standards?
The ASTM lubricity standards require a maximum wear scar — produced in a metal-on-metal abrasion test — of 520 microns. Note, however, that the Engine Manufacturers Association and some regulators (e.g., Europe) have set a standard of 460 microns, or lower. Even if your lubricity oil states it's up to standards, testing labs have found that not all diesel lubricants meet those specifications.
Traditional Diesel Lubricants vs Biodiesel
Biodiesel is emerging as an alternative engine oil lubricity additive. A benefit of using, for example, up to 20 percent biodiesel lubricant is further lowering emissions. Biodiesels do not emit CO2 or SO2 and release less particulate matter than diesel. Many states already require that biodiesel be combined with ultra-low sulfur diesel.
Not all biodiesels, though, perform well as lubricants. Ethanol, for example, could create a harmful acidic concoction that could erode fuel system parts. Ethanol has a higher affinity for water than diesel. When water mixes with acidic combustion byproducts, sulfuric acid is produced. Other potential weaknesses of biodiesel as a lubricant include:
Not all additives are alike. Testing these different standards and lubricity oils in your engines could save you time and money on engine maintenance.
For more information on lubricity additives, contact companies like Lubricant Solutions, LLC.