Latest Spokesman Abstracts

Next Generation High Efficiency Grease for Electric Vehicles EVs Developed in Racing Applications

In recent history significant progress has been made in the efficiency of internal combustion engine vehicles by improving engine and lubricant designs. As we change to electric propulsion, there are opportunities for advances in lubrication technology in the drivetrain, resulting in lower energy consumption and increased battery range. Greases play a significant role in electric vehicle lubrication, such as wheel bearings, constant velocity joints, and e-motor bearings. Little progress has been made in the development of Electric Vehicle specific lubricating greases and many of today’s Electric Vehicle use greases typical of their Internal Combustion Engine counterparts. The design of lubricants to improve efficiency has a long history in racing applications. Lubrication materials must provide critical tribological protection while minimizing energy losses to viscous dissipation, friction, and heat. Technologies developed for automotive racing have resulted in greases that greatly reduce these energy losses while still protecting components. Here we present a novel grease technology that creates dramatic reduction in energy losses and decreases friction while maintaining component life. Reduction of energy losses of 2.5% – 11.2% have been achieved versus formulated racing greases per lubricated bearing. These advancements have demonstrated significant energy savings and future work aims to apply this technology to Electric Vehicles to improve performance and range over the life of the battery pack.

The Matrix Revisted Exploration of Additive Choice with Different Thickener Types

The predominant matrix of choice for grease manufacturers has been lithium for several decades. The increasing imbalance in supply/demand position of LiOH has inspired many grease manufacturers to evaluate alternate thickener types as options for a variety of applications. Unlike most lubricating oil formulations, additive interaction with the grease thickener matrix is a critical element that needs to be carefully considered to create an optimized grease formulation in an efficient and costeffective manner. This paper looks at the impact of grease thickener type on additive selection by examining new data generated in aluminum complex and calcium sulfonate complex base greases and comparing performance to that generated in previous studies that carried out similar testing in lithium and lithium complex (LiCx) base greases. Several different common additives were used in the study including Zinc dialkyldithiophosphate (ZDDP), sulfur sources, an antioxidant mixture and a borated dispersant. Test methods included a wide range of common bench tests along with Thermogravimetric Analysis (TGA) and rheology to examine differences in high temperature performance.

Behavior and Performance of Water Contaminated Bearing Greases in Steel Industry

In water/emulsion-cooled applications such as steel rolling, water contamination of bearing grease is inevitable. This work focuses on the changes in such greases and the consequences induced by water contamination. For this, a calcium-sulfonate-complex grease typically used in bearings was investigated in a comprehensive manner. Special emphasis was given to the absorption capacity and effects of water in the greases. For comparison, four commercially available bearing greases of NLGI class 2 of different thickener types were also examined.

The consistency of the greases was analyzed by means of ASTM D217 (static conditions) and DIN 51810-4 (oscillatory measurement). For performance related analysis, the focus was placed on ASTM D2266 four-ball wear measurement, a special in-house thin film method for oxidation stability, and corrosion protection based on work conducted by Dornhoefer et al. All these tests were carried out in consideration of water ingress into the greases of up to a 40% contamination level.

The findings of these tests support that calcium-sulfonate grease works exceptionally well under high humidity conditions. Finally, a real-life application was used to demonstrate improved cost of ownership and greenhouse gas reduction benefits by using this technology in hot rolling applications.

Next Generation High Efficiency Grease for Electric Vehicles EVs Developed in Racing Applications

Greases can be used in a wide range of applications including wind turbines, electric vehicles, and CNC (Computer Numerical Control) machining. Increases in the demand for lubricating greases can often lead to shortages in the manufacturers recommended grease. When evaluating the compatibility of greases, examination of both the extreme pressure and friction properties between the individual and mixed greases can be critical to insuring equipment reliability. This study aims to investigate the potential tribological effects caused by mixed grease systems that have undergone both mechanical and thermal stress. SRV allows us to compare the tribological response at the surface interface across multiple contact loads to determine extreme pressure (EP) performance. Additionally, SRV can be used to compare the lubricating grease’s ability to maintain boundary layer lubrication over extended test intervals.