A review of mine from the Powertrain and Fluid Meeting, October 29 - November 1, 2007:
Biodiesel (fuel) Impact on Wear Protection of Engine Oils: Fang et al, Cummings; Yamaguchi, Boons, Chevron Oronite Co:
Pure biodiesel fuels (B100) are made of fatty acid esters (FAME). Compared to mineral based fuels the FAME class has higher surface tension, lower volatility, higher lubricity, higher dissolving properties, higher friction reduction, and higher specific gravity. The T50 vaporization is 50 C higher than common D-2 fuels. While some of these properties are beneficial for an engine oil, as a fuel, there are some disadvantages.
Wear of diluted engine oils was tested by ECR, electric contact resistance, HFRR, high frequency reciprocating rig, and WSD, the four ball test.
Biodiesel fuels result in a longer induction time for the onset of viscosity increase from soot generated by B100. There is a better suspension of soot.
With early fuel dilution of the fresh biodeisel fuel, less than 2 %, the wear is actually less. Later, there is a slight increase in the wear rate, particularly after a level or 4 or 5 % of aged biodiesel dilution. This is thought to be a result of chemical reactions with ZDDP. This problem (if it actually exists) may be alleviated by using other chemical additives instead of using ZDDP. In such a condition I think it is possible that biodiesel fuel dilution may actually improve the wear characteristics of the diluted motor oil.
aehaas
Biodiesel (fuel) Impact on Wear Protection of Engine Oils: Fang et al, Cummings; Yamaguchi, Boons, Chevron Oronite Co:
Pure biodiesel fuels (B100) are made of fatty acid esters (FAME). Compared to mineral based fuels the FAME class has higher surface tension, lower volatility, higher lubricity, higher dissolving properties, higher friction reduction, and higher specific gravity. The T50 vaporization is 50 C higher than common D-2 fuels. While some of these properties are beneficial for an engine oil, as a fuel, there are some disadvantages.
Wear of diluted engine oils was tested by ECR, electric contact resistance, HFRR, high frequency reciprocating rig, and WSD, the four ball test.
Biodiesel fuels result in a longer induction time for the onset of viscosity increase from soot generated by B100. There is a better suspension of soot.
With early fuel dilution of the fresh biodeisel fuel, less than 2 %, the wear is actually less. Later, there is a slight increase in the wear rate, particularly after a level or 4 or 5 % of aged biodiesel dilution. This is thought to be a result of chemical reactions with ZDDP. This problem (if it actually exists) may be alleviated by using other chemical additives instead of using ZDDP. In such a condition I think it is possible that biodiesel fuel dilution may actually improve the wear characteristics of the diluted motor oil.
aehaas
