In response to regulatory requirements, lubricant manufacturers are seeking oils that minimize soot thickening and the accompanying soot wear. Formulation technology is being developed by additive manufacturers to satisfy these requirements. For example, such work is in progress at Chevron Oronite Company LLC, using the Cummins M-11 exhaust gas recirculation (EGR) engine test as a surrogate for the anticipated soot wear test for PC-10. Simultaneously, the authors developed bench tests to screen candidate formulations and reduce costs. A ball-on-disc sliding wear test, using a PCS Instruments MTM® tribometer, has been investigated. Sliding conditions at high pressure are required for soot polishing wear. Conditions that correlate tribometer test results with M-11 engine results at high soot concentrations (∼9 per cent) have been found. Both ball wear and Stribeck curves were determined in these tests. The high-wear oil progresses from mixed lubrication conditions to boundary lubrication at higher sliding speeds than the low-wear oil. X-ray photoelectron spectroscopy experiments were also conducted on the ball wear scars, revealing differences in the chemical constitution of the tribofilms from the two oils.

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An ion-exchange process for removal of metals from liquid pyrolysis oil at ambient temperature has been developed. Pyrolysis oil is first blended with a polar and low-viscosity organic solvent or a solvent mixture to adjust its kinematic viscosity to about 60 mm2/s or less. The blended oil is then treated with strongly acidic ion-exchange resin. The metal content in the treated oil can be reduced to 5 ppm or less. The equilibrium isotherm and kinetic studies indicate that the exchange is a pseudo-first-order process. The rate order observed is Na+ > K+ > Mg2+ > Ca2+ ≫ Fe3+.

A fuel heat of vaporization (ΔH vap) is a fundamental thermodynamic property and an important parameter for internal combustion engine design. The ΔH vap value is measured with a newly developed vacuum thermogravimetric analysis (VTGA) method. The technique is applicable to jet and diesel range fuels. The measured values for the selected components in the fuels agree with the literature values within a range of ±5%. VTGA is a quick, cost-effective, and accurate method to measure the ΔH vap of renewable fuels. The ΔH vap values for binary mixtures of fuels can be simply estimated from the ΔH vap values and mix ratio of the parents.

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