20 Minutes With Dr. Steve Przesmitzki
Karl M. Phipps, Managing Editor | TLT 20 Minutes June 2013
Working for the DOE’s Vehicle Technologies Program, this technology development manager examines how advanced lubricants are improving vehicle performance.
DR. STEVE PRZESMITZKI - The Quick File
Dr. Steve Przesmitzki is a technology development manager within the U.S. Department of Energy’s (DOE) Vehicle Technologies Program. His primary responsibility is supporting the development of energy policy and management of research programs as applied to fuels and lubricants in transportation.
Previously, Steve worked for two years as a project manager for the DOE’s National Renewable Energy Laboratory and 14 years in vehicle powertrain design and development at Ford Motor Co. While at Ford, he spent significant time developing powertrains for flexible-fuel vehicles, as well as developing onboard diagnostic systems. Steve was awarded the Society of Automotive Engineers (SAE) Myers Award and the SAE Lubrication Award in 2008 for his work on lubricating oil transport throughout the piston ring pack of internal combustion engines.
Steve holds a doctorate from the Massachusetts Institute of Technology, along with a master’s of science from the University of Michigan and a bachelor’s of science from Kettering University—all in mechanical engineering. He is also registered as a professional engineer in Michigan.
Dr. Steve Przesmitzki
TLT: Why is the DOE interested in studying advanced lubricants?
Przesmitzki: Advanced energy-conserving lubricants are one of the quickest ways to improve the fuel efficiency of America’s vehicle fleet. The DOE’s Vehicle Technologies Office seeks to decrease petroleum dependency and reduce greenhouse gas emissions. As part of our advanced transportation technologies portfolio, we expect advanced engine lubricants can improve engine efficiency by 1-2 percent across the U.S. vehicle fleet in the next 5-10 years.
In the U.S. approximately 240 million cars consume over 130 billion gallons of gasoline per year, while heavy-duty trucks consume an additional 60 billion gallons of diesel fuel per year. Improvements in engine lubricants, which are changed frequently, have the ability to improve efficiency in the entire fleet. Improvements in other lubricants, such as axles and manual transmissions, are also being pursued.
TLT: What DOE projects are you currently working on?
Przesmitzki: Our program is focusing on improving lubricants in several ways. For example, one area we are pursuing is advanced additives, particularly nano-sized additives. Through this work, we are looking for unique particles or compounds that will reduce boundary friction and wear. The advanced additives may also enable lower-viscosity fluids to be used with the same level of engine protection as current products on the market, thereby allowing further reductions in engine hydrodynamic friction.
We are also investigating advanced base oils. It is common knowledge that higher viscosity index base oils are desirable for engine performance. We hope to help determine when advanced base oils are worth the extra cost. We also are working on advanced materials, coatings and surface textures. We try to achieve these goals through several different approaches. One path is collaborative projects with industry, while others are through national labs and universities.
TLT: What impact will improving fuel economy have for older-model vehicles?
Przesmitzki: Developing newer lubricants for older vehicles is not a simple task, but advances are already being made. One obstacle to greater improvements is the impact of lower-viscosity lubricants on engine wear and performance. Manufacturers are testing lower-viscosity lubricants on newer vehicles to determine appropriate recommendations. We do not advocate using any viscosity grade that is outside of the manufacturer’s recommendation. Even with a set viscosity, a higher viscosity index (VI) base oil and improved additive package can give real-world fuel economy and performance improvements in older-model vehicles. A longer service life also can often offset the higher purchase price of premium engine oils, so the net result is a cost savings for the consumer and a benefit for the country.
J. Qu, et al., ACS Applied Materials & Interfaces 4 (2) (2012) 997.
TLT: With regards to backwards compatibility, should advanced lubricants, materials/coatings and additives be developed with older-model vehicles in mind?
Przesmitzki: The DOE is supporting research in these areas and providing industry with the technical assistance and research needed to pursue different approaches. We have projects looking at new or advanced base oils that are more compatible with newer model vehicles, advanced coatings and additives.
Our work on additives is most applicable to the older-model vehicles, i.e., legacy fleet. Improvements to legacy vehicles will have the largest overall fleet impact in the short run, while the largest improvements per vehicle might come from new vehicles.
Figure 2. Results from a ionic liquids developed at Oak Ridge National Lab shows lower friction in mixed and hydrodynamic lubrication than conventional oils along with increased scuffing resistance in boundary lubrication.
G. Mordukhovich and J. Qu*, et al., Wear, DOI: 10.1016/j.wear.2012.11.076
TLT: Can advanced lubricants have an impact on vehicle emissions?
Przesmitzki: The DOE’s Vehicle Technologies Program is pursuing a R&D portfolio to examine the impact of advanced lubricants on vehicle performance. The portfolio includes research on new or advanced base oils, coatings and additives and seeking to address several challenges/barriers including (1.) how lubricants affect spark-knock tolerance in gasoline engines, (2.) how they affect the “superknock” or “mega- knock” phenomenon in newer, high-performance engines and (3.) how they affect particulate matter (PM) emissions. This work will help lay the foundation for understanding the impacts of newer lubricants and advanced additives on emissions.
TLT: When considering fuel economy and emissions, what tests should be developed in formulating a new lubricant?
Przesmitzki: We see a need to develop some means to correlate basic tribological testing from bench-top rigs to fuel economy in a vehicle. Our research and bench-top testing is helping to collect the data that can be used to enhance computer- aided engineering design and modeling. For example, we are working with a consortium of industry and academia partners to provide boundary friction data with various coatings and additives to enhance predictive models.
In many instances, basic tribological tests have shown promising improvements in boundary friction but don’t materialize when tested in an engine. In some instances, a polishing effect or viscosity change is more responsible for the differences than the proposed additive or base oil. Also quite common is an additive that shows promise with a non-formulated oil but does little or even has a detrimental effect when used with fully-formulated oil. Full certification testing of a lubricant is time consuming and expensive. We hope to provide guidance on the most appropriate bench-top tests and test conditions that correlate well with vehicle fuel economy.
Figure 3. Role of surfactants and nanoadditives. The images represent a brief survey of several candidate nanoadditves tested at Argonne National Laboratory. The results compare friction and wear under identical conditions (reciprocating ball-on-flat in Group IV base oil, 130 C). Adding a surfactant to a base fluid (Group IV) reduces asperity friction, but has little impact on wear (see the left image). Adding nanoadditives (carbon-based, nitride, oxide) can be beneficial for both friction wear relative to baseline (see the middle image). Addition of nanoadditives and surfactants can further reduce friction but not necessarily wear (see the right image).
TLT: How will the design of materials and coatings in new vehicles interact with future additive packages?
Przesmitzki: We think some of the greatest benefits in friction reduction will come from a co-design of the lubricant along with the engine hardware, including new materials, surface textures and coatings. One potential issue is how lubricants interact with non-traditional materials.
Current lubricants have been developed to work well with ferrous and aluminum materials. Before advanced coatings, ceramics or lightweight materials such as titanium become widespread in an engine, R&D needs to be done to ensure they will not have a detrimental effect on friction. This is the sort of research the government is well suited for since it is precompetitive and can advance the state of knowledge that transcends other industries. This knowledge base can be applied beyond engines and vehicles.
You can reach Steve at steven.przesmitzki@ee.doe.gov.