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Lubricants: Pouring in fuel economy

Oil. Protect it must, but green it'd better be, too. Lubricant engineers couldn't be blamed for issuing a collective sigh of relief that they have no further emissions-driven API oil-service categories to wrestle into existence

Oil. Protect it must, but green it'd better be, too. Lubricant engineers couldn't be blamed for issuing a collective sigh of relief that they have no further emissions-driven API oil-service categories to wrestle into existence.

Yet they get no break from the lab as trucking's thirst for greater efficiency is demanding they engineer motor oil that will better help fleets save fuel with whatever type of EPA-compliant diesel engine they run or will soon run.

That greater fuel efficiency can be delivered through lubricant technology is something lubricant suppliers agree upon readily. And they concur that fuel economy can be boosted without compromising the engine protection afforded by lubrication. How best to deliver on that dual promise largely involves figuring out how best to lower the viscosity grade of motor oil so diesel engines can run on less fuel.

The complicating factor is there's more than one way to lower viscosity without sacrificing the engine protection that is the be all and end all for pouring motor oil into the works in the first place.

“There can't be a trade-off between engine protection and fuel economy,” says Dan Arcy, OEM technical manager for Shell Lubricants. He says that idea would never sell, especially now that many fleets are keeping their trucks longer.


According to Arcy, “lighter-vis grades can provide greater fuel economy and these gains can be significant.” In Shell's case, he is referring to a 10W-30 semi-synthetic vs. a 15W-40 mineral oil. “Trials for our new Rotella T5 10W-30 motor oil showed a reduction of 1.6% in fuel consumption.” He notes the new T5 will be available as a 10W-40 product as well, which he says will pack less of a fuel economy punch.

“Because it's a synthetic blend, T5 provides the needed protection for engine bearings and linings, etc. and at a lower viscosity to enhance fuel economy,” he remarks.

Darcy explains that Shell went with a semi-synthetic base oil to produce the lower-vis T5 because “a semi-synthetic base oil allows for greater control of the formulation, which allows for the lower viscosity grade. You end up with greater fuel economy with a little better engine protection and better cold-temperature protection. But, again, the main advantage is the boost in fuel economy.”

He notes that even with the higher purchase price of the semi-synthetic T5 compared to a mineral oil-based product, the “payback is still there thanks to the 1.6% reduction in fuel consumed.”

Darcy also points out that along with mineral-based and semi-synthetic heavy-duty motor oils, Shell offers a full synthetic product. “We feel choosing the right product is determined by the truck's duty cycle. Some customers are interested in semi-synthetics, others in full synthetics. There is a difference in price so, for them, it comes down to which value proposition fits their fleet,” with full synthetics typically favored where low ambient temperature performance is critical.

“Fleets always need to control their maintenance and fuel costs,” Arcy adds, “but many are also becoming more aware of their environmental footprint. [Using a 10W-30] to reduce fuel use also cuts back on carbon dioxide emissions, and that is important to some fleets and shippers as well.”

When it comes to moving to lower-vis motor oil, according to Mark Betner, product manager, heavy duty lubricants for Citgo, it's a matter of educating customers on how far lubricant technology has advanced.

“Engine makers are starting to talk about this [low-vis oil to gain fuel economy] now that they've come through the thicket of reducing emissions,” Betner says. “Once they become more engaged with this topic, it will increase the educational effort for the trucking industry. And, of course, many fleets will benefit once they start hearing about what other operations are doing who were the early adopters.”

Further, he says that “there need not be a compromise between optimizing fuel economy via engine lubrication and wear protection. A properly balanced and formulated ‘low low’ or wide-temperature range heavy-duty engine oil is fully capable of achieving both performance advantages. In fact, a 5W-40 synthetic engine oil provides reduced wear protection at both lower startup temperatures and higher operating temperatures.”


As Betner sees it, just as fleets once “got out of the straight-weight comfort zone,” more will take advantage of new lubricant technology to benefit from low-vis oil. “We now have to move out of our 15W-40 comfort zone. In fact, we're already seeing 5W oils in use for commercial vehicles in Europe. There's an education hump about this we all have to get over. After all, anything that will improve fuel economy should be seriously considered.”

Betner says that while low-vis products are already available, the heavy-duty marketplace is not widely embracing this advance yet. He says a good place to go for some convincing is the EPA's SmartWay web site. “There they tell you that the combined use of a synthetic driveline lube and a low-vis 5W-30 or 5W-40 full synthetic motor oil will produce about a 3% fuel savings. That amounts to 500 gals. less fuel burned per power unit and that savings means you're also cutting air pollution by 5 metric tons.

“Using a full synthetic base oil allows getting down to a five-weight product that saves fuel and also optimizes low-temperature engine protection and drain intervals,” Betner continues. “But I have to put an asterisk on extending drains,” he adds, “because a fleet should never do so on the strength of oil quality alone. It's better to think of it as the potential for drain optimization; so be sure to perform oil analysis to validate the drain schedule.”


Whether to go with a synthetic blend or a full synthetic oil will come down to “education and understanding the possibilities,” contends Betner. “Many get scared off by the initial purchase price [for full synthetics], but choosing one can pay off if all the cost factors are weighed properly for ROI.”

Betner notes that Citgo offers both full synthetic and synthetic blend products, but says “to get the full low-vis advantage requires the full synthetic.” He adds that synthetic blends are “usually premium products and so will help with drain optimization and also to address concerns about protecting engines that burn biodiesel” even if they don't deliver the highest mpg advantage.

“At the end of the day,” Betner adds, “the cost of full synthetic heavy-duty engine oil must be evaluated for each fleet vs. a conventional oil, and this is why some heavy-duty engine oil manufacturers have offered synthetic blends as an alternative to enhance longer engine oil change intervals and the overall quality of the formulation.”

Len Badal, commercial enterprise manager for Chevron Global Lubricants, says Chevron Delo 400 LE 10W-30 has been formulated using a Group II (mineral) base oil and a proprietary additive package that “provides excellent fuel economy savings and engine wear protection based on appropriate OEM recommended drain intervals.”

He says the new product was developed to avoid a trade-off between fuel economy and engine wear protection. “If you're boosting mpg with a lower-viscosity grade oil, you must still be able to provide equal engine wear protection as a similar API CJ-4 approved 15W-40” product.


To prove that dual capability, he reports the oil underwent bench testing with the “latest OE engines from Detroit Diesel, Volvo, Mack, DAF and Cummins and was field-tested in several over-the-road fleet applications.” As for the mpg performance of Delo 400 LE 10W-30, Badal relates that “we have shown it will provide up to a 1% fuel economy gain over a 15W-40 oil.”

Badal says the lower the viscosity grade, the less internal friction is generated by the heavy-duty engine oil. That lessens the workload on the engine and boosts fuel efficiency.

Rather than use a synthetic blend or full synthetic, according to Badal, Delo 400 LE was formulated as a conventional product by using the company's proprietary ISOSYN Technology. Using a Group II hydrocracked (severely refined) mineral oil combined with “advanced additive” technology, ISOSYN creates products that rival synthetic lubricant performance in critical engine tests while maintaining costs similar to mineral-based oils.

“Delo 400 LE 15W-40 has been favorably compared to heavy-duty synthetic 5W-40 products,” Badal adds. “Specifically, we have demonstrated statistically that it provides equal fuel efficiency, wear control, deposit control and extended drain capability at half the cost to the customer.”

Badal points out that Chevron does offer Delo 400 LE 5W-40 full synthetic heavy-duty engine oil but it is “typically not needed by the average fleet. Rather, it is normally used by fleets that operate in subzero temperatures since it has a better pour point performance allowing better cold start protection.” He adds that the company does not offer a synthetic blend heavy-duty oil. “We see our Delo 400 LE with ISOSYN Technology as providing excellent protection at a better cost point than synthetic blend heavy-duty engine oils for most fleet operations.”

“A semi-synthetic is sometimes seen as a marketing ‘feel-good’ product,” he remarks. “Most fleets do not see an advantage to semi-synthetics. In general, you don't get a lot of extra performance from a semi-synthetic vs. API CJ-4 approved conventional heavy-duty oil offerings for most typical over-the-road fleet operations.”

Looking down the road, Badal “says we will continue to see the over-the-road fleet market moving towards fuel-efficient, heavy-duty engine oils as owners become further comfortable with the technology and savings. As the next API category is developed, there may be further emphasis on even lower viscosity engine oils (below even the new 10W-30 viscosity grades) as additional curbs on emissions need to be met with even more stringent fuel economy standards.”

He remarks that with the completion of the 2010 emissions cycle, “there is no doubt that the focus on fuel economy will only increase. And, of course, if you can increase fuel economy, you will decrease emissions as well.”

Badal reports that at least “one major on-road [engine] producer is on board with 10W-30 as a factory fill. That will put pressure on others to consider lower-vis grades and help oil to be seen more as part of the overall fuel economy equation.” He adds that adoption of lower-vis oils in the aftermarket will be driven by how fast large and regional fleets move toward using them.


“Naturally, there's a lot of concern about fuel economy, especially given the dramatic increase in prices last year that drove fuel to be as high as 60% of a fleet's operating budget,” points out David Pack, international C&I marketing manager for Valvoline International.

“The result,” he continues, “is that so many people are marketing all sorts of fuel economy solutions that customers are still not impressed when firms like Valvoline have statistically valid data” to prove their claims.

“There are various factors that influence the lubricant's capacity to impact fuel efficiency that we have been looking at,” says Pack. “These include how the oil ‘ages’ in service and how it reacts to that aging process. We're doing a lot of work around a new global oil platform and will soon make what we think will be a game-changer announcement.”


Vic Kersey, technical director, says that Valvoline has “looked at a number of viscosity grades, from 0W-20 up to 15W-40, to take a different approach to oil formulation. It involves much more than looking at the SAE grade classification. When you drop down to, say, a 0W-20, you can end up going the other direction, away from protection and even to affecting the oil's boundary protection of the engine. At that point, what you would need are engines designed for such low-vis grades.”

At the moment, according to Kersey, the company's most fuel-efficient oil is Valvoline Premium Blue Extreme 5W-40, which is a full synthetic product. “We've statistically proven at a 90% confidence level that it will provide a fuel economy boost of up to 3% vs. a leading conventional 15W-40 CJ-4 product,” says Pack. “Our approach is very technical and going forward,” he adds. “We view the need as offering a solution [for fuel economy], not a single product.”

Matt Rudd, fleet marketing manager for Castrol Heavy Duty, contends the “key thing about fuel economy [claims] is being able to have fleets see the benefits. The ability of fleets to gauge and appreciate the lubricant's role in fuel economy will be critical going forward.

“To be sure,” he continues, “there's no reason to believe lower-vis oil — whether 10W-30 or even 5W-30 — and engine protection are mutually exclusive. That's because you can definitely protect engine surfaces with advanced wear protection formulas.”

Rudd says that “to reap the benefits of lower viscosity, to really deliver on fuel economy, formulators will have to start switching to more synthetic base oil stocks. So far, synthetic blends have been seen by the market as primarily for extending drains, even to doubling OEM recommendations.

”That's where we see things at the moment,” he continues. “Going forward, though, we'll see a movement to full synthetic base stocks. How quickly that will happen will depend on how quickly the mind-set of fleets will change about oil technology; that is, how soon will buyers move beyond 15W-40 to lower-vis grades?”


Rudd notes that Castrol currently markets a full synthetic that he says will deliver up to 2% greater fuel economy than a conventional 15W-40 product.

“A wholesale shift to lower-vis and synthetic products will require an engine maker or some large fleets to adopt the technology first,” he adds. “Given the current economic climate, we are definitely seeing fleets starting to become more open to doing things differently and considering new solutions.”

That motor oil formulation will increasingly be seen as another way to pour more fuel economy into diesel engines is a foregone conclusion in this era of tight cost control and wider environmental awareness.

What is not is which heavy-duty motor oil formulation type — conventional, full synthetic or synthetic blend — will eventually be part of a future oil-service category.

Right now, though, there are plenty of quality products for fleet owners to choose from that promise more miles per gallon with every oil change.

To the well

Technical information is available from these and other suppliers of heavy-duty motor oil:








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