Technical Paper
Dimethyl Ether: New Advances in Wear Testing: Theoretical and Experimental Results
2003-10-27
2003-01-3286
The issues addressed in this paper are investigation of the wear mechanisms present in the standard lubricity test for diesel oil: The High frequency Reciprocating Rig (HFRR). The HFRR is a laboratory wear test using a ball on disk configuration. The result of a test is the wear scar diameter (WSD) on the ball. Up to now, all analyses indicated that fuel viscosity influences the wear scar size and fuel performance in full-scale pumps. The wear scar size could then be a result of hydrodynamic lubrication (at least a significant part of it) and not of boundary lubrication as it was the original intention of the test. The appearance of an excellent volatile fuel for diesel engines, Dimethyl Ether (DME), has resulted in new wear tests such as the Medium Frequency Pressurised Reciprocating Rig (MFPRR), a pressurised version of the HFRR. DME has a about 25 times lower viscosity than diesel oil so the MFPRR viscosity sensibility issue is seriously aggravated for this fuel.