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Lubricating oil viscosity is commonly measured by the kinematic method as outlined in ASTM 0445. This method is also used to measure drain oil viscosity as an indicator of soot induced thickening. Drain oils can contain solid particles and exhibit non-Newtonian flow behavior. This paper discusses the use of rotational rheometers to measure the rheology of drain oils. These instruments have been used for many years in other industries (food, paints and coatings) to measure particle filled, non- Newtonian fluids. The rotational method yields the general flow curve of viscosity versus shear rate as compared to the single point, low shear kinematic viscosity measurement. The rotational method includes the kinematic viscosity single point but also yields significantly more information on shear behavior. Both pumpability (low shear) and flowability(higher shear) can be ascertained from the rotational method.

Regulations reducing emissions worldwide are the driving force behind the trend to converging diesel engine design strategies among manufacturers. This results in common engine lubricant performance and the need for a global performance platform for diesel engine lubricants (1, 2). This paper chronicles a multi-year project that defined a diesel engine lubricant platform to meet global Original Equipment Manufacturer (OEM) requirements. The design of the additive chemistry required to achieve the platform targets is described. Demonstration of the performance capabilities of the new technology in engine tests that constitute international specifications and field testing is also discussed. The results suggest that formulating a heavy duty diesel engine oil to meet a variety of worldwide lubricant requirements results in a more robust formulation, outperforming oils designed to meet only regional requirements.