- Method ASTM D6079
- Repeatability 80um @ 60° C
- Reproducibility 136um @ 60° C
- Blending non-linear
- Additive Correction Yes
This test method was created in light of more restrictive sulfur regulations introduced by the federal government. Sulfur acts as a natural lubricant in diesel fuels and when it is removed it can cause excessive wear in the fuel system. The fuel injection system consists of a high pressure pump that will raise the diesel from 1-50psi up to 25,000psi to feed the fuel injectors. With this much pressure in the system lubrication is essential to its lifespan. In order to combat this lack of lubrication additives have been developed to supplement the lack of sulfur. These additives are used in all on road ULSD.
The method is performed using a High Frequency Reciprocating Rig. A test specimen ball is loaded into the top portion of the carrier and a bottom specimen disk is loaded into the sample well. 2mls of the test fuel is then loaded into the carrier. Now a 200 gram weight is then hung on the top specimen holder to ensure constant pressure is applied between the ball and disc. Once fully assembled the unit heats the fuel and begins to reciprocate. This will cause a scar to form on the ball and disc as the two surfaces interact. When the test is complete the top specimen is removed and the scar is measured (length and width) using a microscope. The more lubricating quality the fuel possesses the smaller the scar is.