Shell advances lubricants to improve fuel economy, alt-fuel compatibility

  • 16-Oct-2013 04:52 EDT
Slide roll rig for engine component wear test.jpg

Designed by Shell to qualify diesel engine oils, the slide/roll rig is used for testing diesel engine component wear. With it Shell can test a lot more candidates than with the engine test. Researchers can also use it to test ideas that fall outside the predictable area of normal behavior, which would never be given a chance otherwise.

In recent years, Shell established a Lubricants Discovery Hub consisting of a global multidisciplinary team of scientists who focus on innovation within lubricants. Team members are located in the U.S., the U.K., and Germany, and the group has collaborations with universities and companies across the globe. “Lubricants play a significant role in fuel economy, and our team is focused on cutting-edge technology in this area,” said Allison Falender, Technology Manager for Shell’s Lubricants Discovery Hub. Falender recently spoke with SAE Magazines Associate Editor Ryan Gehm about some of these cutting-edge technologies and how they can help OEMs meet stricter fuel-economy regulations.

Can you explain the R&D process within the Lubricants Discovery Hub?

The Lubricants Discovery Hub is a unique group because we are specifically focused on innovation in themes. The themes that we focus on are themes that are most important to our customers: fuel economy, durability, and sustainable fuel compatibility. What sustainable fuel compatibility means is designing lubricants that will help with the deployment of various new fuels. This could be everything from ethanol to biodiesel to LNG, just depending on whatever fuels are being deployed in various regions…. So we spend a lot of time looking for new chemistries that can go into lubricants. But one of the other really interesting things that our team does is we spend a lot of time gaining a fundamental understanding of engines and lubrication. That knowledge enables us to have meaningful conversations with OEMs based on the latest and future trends in technology.

With the new sustainable fuels, is there a real difference in the lubricants vs. those for traditional fuels?

These are new fuels that are just being deployed, so we’re at the very beginning process of understanding if there might be any significant challenges. We did a project with Leeds University in the U.K. that was specifically designed to look at the effects of ethanol in the engine and really to try and understand how ethanol compares to other fuels with respect to tribology…. Now we do currently have a product that’s fit for purpose in our Rotella portfolio; we have the technology available today to enable deployment of LNG and CNG, but we’re working to understand even more, as more and more vehicles adopt this new technology.

What’s cutting-edge today in lubricants?

It’s an incredibly exciting time to be in lubricants research. I think one of the most significant cutting-edge items are low-viscosity formulations. In the current API engine oil classifications, the SAE viscosity grade is 0W-20. If you go to lower viscosities, you enable improvements in fuel economy. So for GF-6, which is a specification that’s scheduled to be rolled out in late 2016 or early 2017, there’s a potential that there’s going to be a new viscosity grade, which is a 0W-16 or a 5W-16. This is a significantly lighter viscosity grade. What the Lubricants Discovery Hub is doing to help prepare for the deployment of the 0W-16 is developing expertise in ultra-low-viscosity oils that can help improve fuel economy. So we’re partnering with a number of OEMs to co-engineer vehicles and lubricants. For example, in a partnership with Gordon Murray Design we were able to achieve an urban-cycle fuel-economy improvement of up to 6.5% using a prototype 0W-10 oil. What we’re essentially doing is trying to see how low you can go with viscosity and really what the limits are using these prototype oils, so that over the next couple years as 0W-16s and 5W-16s enter the market, we have extensive knowledge in this area and also understand how these lubricants interact within the engine.

Is this trend global, the move toward lower-viscosity oils?

The trends are global, but the GF-6 specification specifically is in the United States…. I think the entire industry is very eager to try and improve fuel economy to reach some of the challenges associated with reducing CO2 emissions. And we’re very eager to partner with OEMs to try and help them to meet those targets based on our knowledge of the low-viscosity oils.

What is possible in terms of FE improvement with lubricants?

We’ve done some fairly significant work calculating what we call the "size of the prize"—the potential for improvement in fuel economy. Lubricant fuel-economy potential is directly related to the amount of friction in the engine, and the amount of friction in the engine depends on three things: hardware design, the lubricants, and the running conditions of the engine (time, temperature, and speed). Reaching the theoretical maximum reduction in friction is very challenging. With 0W-20 oils we’ve been able to make a fuel-economy improvement of about 4.3%, and with the 0W-10, we’ve been able to get up to a 6.5% improvement using a European test, the CEC M111 test. We have a very deep fundamental understanding of this relationship within the engine, and the role that the lubricant plays.

Another role that lubricants play is in enabling the deployment of new types of vehicles that [get better] fuel economy. For example, the trend in the industry is toward downsized turbocharged engines. One of the challenges with downsized turbocharged engines is the formation of deposits, which can cause challenges with performance. The lubricants that we develop have a special technology to help keep the engine clean and prevent the formation of deposits, so we are able to see the deployment of these new types of engines that are more fuel efficient, enabled by the ultra-clean lubricants that we develop.

Imagine when you buy a new car and you see that sticker that gives the miles per gallon that you’re going to get. That mpg rating is based on a brand-new engine; once the engine becomes dirty, fuel economy suffers. One of the things that we’ve recently found is that a clean engine allows you to drive on average an extra 550 miles per year vs. a dirty engine. So ultra-clean lubricants can help with fuel economy both directly and indirectly by keeping the engine clean.

What else is on the horizon for advanced lubricants?

Our team has developed a calculator that enables us to predict the film thickness of journal bearings based on [their] geometry. The reason that this is very significant is because a lot of people are nervous to go to the lower-viscosity oils because of concerns that the film won’t be thick enough. We have the knowledge to understand how thick that film will be, and can work directly with our partners to help them understand, based on the viscosity grade and the shape of the journal bearing. They can then make the decision about how to design the journal bearing and what lubricant will be ideal for use with that journal bearing.

Are these innovations and issues relevant to other transportation sectors?

The journal-bearing calculator that we’ve developed, we can adapt that to engine equipment of many different types. The other thing is that as you go to these lower-viscosity oils in any type of application, the biggest concern that a lot of people have is durability, or preventing wear. You want to make sure that the equipment is properly protected, even when you have a thinner oil. Our team is working on developing a number of different novel additives that help with coating the surfaces and making sure equipment of all types, both on-road and off-road, have that proper protection.

What other collaborative efforts does Shell have with universities?

One example is we’re working with Tsinghua University in China. They’re developing dimpled surfaces—metal surfaces with various types of textures—and we’re working with them to co-develop lubricants to understand how those lubricants might interact with these new types of materials. That enables us to have discussions with OEMs about some of the new materials that might be coming out, but additionally we have a greater understanding of what lubricants will work with those new materials that could help in achieving [better] fuel economy. We’re also working on several projects with the Massachusetts Institute of Technology—again, fundamental projects to learn what’s going on in the engine.

And it goes even further. My team plays a very big role in the Shell Eco-marathon, a global event where students literally from all over the world come together and design fuel-efficient cars. We want to see what exciting technology might be out there in the vehicles that are going to be helping to meet the very challenging energy-efficiency mandates, and understand what the lubrication requirements are. We actually have a tribology award that we’ll be giving out next year at the Eco-marathon to really encourage students to look at the role that the lubricant, tribology, and friction play in engine design.

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