ASTM D6078-04

Diesel fuel injection equipment has some reliance on lubricating properties of the diesel fuel. Shortened life of engine components, such as diesel fuel injection pumps and injectors, has sometimes been ascribed to lack of lubricity in a diesel fuel.

The trend of SLBOCLE test results to diesel injection system pump component distress due to wear has been demonstrated in pump rig tests for some fuel/hardware combinations where boundary lubrication is believed to be a factor in the operation of the component.⁶

The tangential friction force, as measured in the SLBOCLE test, is sensitive to contamination of the fluids and test materials, the presence of oxygen and water in the atmosphere, and the temperature of the test. Lubricity evaluations are also sensitive to trace contaminants acquired during test fuel sampling and storage.

The SLBOCLE and High-Frequency Reciprocating Rig (HFRR, Test Method D 6079) are two methods for evaluating diesel fuel lubricity. No absolute correlation has been developed between the two test methods.

The SLBOCLE may be used to evaluate the relative effectiveness of diesel fuels for preventing wear under the prescribed test conditions. If a standard SLBOCLE rating has been set, then the single-load test provides a more rapid evaluation than the incremental load test. Correlation of SLBOCLE test results with field performance of diesel fuel injection systems has not yet been determined.

This test method is designed to evaluate boundary lubrication properties. While viscosity effects on lubricity in this test method are not totally eliminated, they are minimized.

1.1 This test method evaluates the lubricity (load carrying ability) of diesel fuels using a scuffling load ball-on-cylinder lubricity evaluator (SLBOCLE).

1.2 This test method is applicable to middle distillate fuels, such as Grades Low Sulfur No. 1 D, and No. 2 D diesel fuels, in accordance with Specification D 975; and other similar petroleum-based fuels which can be used in diesel engines.

Note 1- It is not known that this test method will predict the performance of all additive/fuel combinations. Additional work is underway to further establish this correlation and future revisions of thistest method may be necessary once this work is complete.

1.3 The values stated in SI units are to be regarded as the standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.