Making Donuts

May 1, 2000
Not one but two new motor-oil service classifications in the worksThere was a time when rolling out a new API (American Petroleum Institute) oil-service classification - known as a "donut" for the circle in which its designation is inscribed on packaging - was something of a watershed event.But since the federal Environmental Protection Agency (EPA) began clamping down hard on diesel emissions in

Not one but two new motor-oil service classifications in the works

There was a time when rolling out a new API (American Petroleum Institute) oil-service classification - known as a "donut" for the circle in which its designation is inscribed on packaging - was something of a watershed event.

But since the federal Environmental Protection Agency (EPA) began clamping down hard on diesel emissions in the '90s, the oil industry has been forced to whip up new donuts at an increasingly faster clip.

The latest API classification for heavy-duty diesel engines, CH-4, which came into being less than two years ago, will itself be superceded by a new one - currently dubbed Proposed Category 9 (PC-9) - just over two years from now.

PC-9 is being developed specifically to address the needs of diesel engines engineered to meet the EPA emissions regulations that will become effective in October 2002.

But that's not all. The oil industry has also begun work on the next category, PC-10, which will focus on the impact of the even more demanding EPA regs expected to hit truck engine makers in 2006.

API ultimately licenses oil companies to display service classifications such as CH-4 on the packaging of qualified products.

But it's the American Society of Testing & Materials (ASTM) committee on heavy-duty engine oil classification that sets the limits and verifies the testing used to develop these classifications.

According to the chairman of that committee, Jim McGeehan, manager of engine oil technology for Chevron Products Co., PC-9 is being drafted so oil can be formulated that will counter the ill effects of adding exhaust-gas recirculation (EGR) systems to engines.

EGR systems are seen as the best means of complying with the EPA's requirement that engines built after October 2002 emit no more than 2 grams of nitrogen oxides (NOx), which is half the amount truck diesels are currently allowed to pump into the air.

"It's expected that engine makers will use what's termed cold EGR technology to achieve the NOx reduction required for October 2002," McGeehan reports.

The "cold" in a cold EGR engine refers to how a portion of hot exhaust air (perhaps 15%) is drawn through an intercooler to bring its temperature down from 1,200 deg. to 250 deg. before mixing it with cooler (110 deg.) inlet air.

Although the actual functioning of an EGR system is a bit more complex, the scientific basis of EGR is simple enough to grasp: in diesel engines, NOx emissions go up as peak flame temperatures rise. Hence the need to cool exhaust gas.

The ASTM panel is working to complete PC-9's development process in time to allow oil licensed under the new API category to reach the field six to nine months before the new engines. By the way, if naming tradition holds, expect PC-9 to come to market as API Category CJ-4.

According to McGeehan, PC-9 will incorporate updated OEM oil specs from Caterpillar, Cummins, and Mack that address how the addition of EGR affects heavy-duty diesels.

The new Cummins and Mack specs were written to ensure oil formulations protect against ring, liner, bearing, and valvetrain wear, while the revised Cat spec is mainly concerned with how oil will ward off piston deposits.

Testing 1, 2, 3... With the addition of those three new specs, developing PC-9 will actually involve meeting limits set forth by 14 different laboratory tests, which McGeehan says will make for "a real, substantial improvement in oil quality."

He points out that at this point the ASTM committee is defining the procedures for running the tests required by each of the OEM specs. Given that, he expects the limits actually needed for formulating PC-9 oil will be placed by the first quarter of next year.

From there, the API licensing process would kick in. Seeking to ensure a level playing field, API will again keep the new "CJ-4" donut off all oil for one year. That way, smaller-scale oil suppliers get a chance to catch up with their big-name competitors in reformulating product.

At any rate, if all goes according to plan, oil engineered for the engines arriving courtesy of EPA in October 2002 will be in the distribution pipeline months ahead of time.

Then, there's PC-10. McGeehan says task force meetings are already under way for this category. Again, it will address the impact of diesel emissions limits that EPA is expected to mandate for 2006.

As that EPA proposal now stands, further reductions in both NOx and particulates will be required. These limits may force engine makers to use catalytic converter systems as well as particulate filters or "traps."

Last month, EPA was to have announced the specifics of the 2006 emissions rules. However, as of presstime, the agency had issued no further word.

Getting back to 2002, Ralph Cherrillo, technical advisor for engine oils for Equilon Lubricants Co., which markets Shell and Texaco brand products, says PC-9 oils will have to be formulated for "abuse tolerance" to maintain the extended drain intervals many fleets now enjoy.

"EGR engines will generate more acids," he explains, "which will move from the exhaust back into the combustion chamber. EGR works well for getting NOx under control but it acidifies crankcase oil and produces more soot. So, EGR puts a larger burden on engine oil.

"We also expect some amount of engine coolant will be used to cool the exhaust gas, so crankcase oil may end up 25 to 30 deg. F hotter than in current engines," Cherrillo continues. "This is another impact that will have to be addressed."

Battle of wills Cherrillo says getting the PC-9 category completed in time will be a continuation of the recent progress made in boosting oil quality through the API donut process. Nonetheless, he says there will be a "battle of wills" fought in getting to 2002.

"On one side are the truck users, who want extended drain capability, and the engine makers, who recognize that desire and want to offer it as a competitive marketing tool," Cherrillo says. "On the other are the oil formulators, who know what capabilities are 'built into' a lubricant.

"There always comes a point when an oil's additive package is depleted and it should be changed to protect the engine," he continues. "The real battle is over changing the oil at the right time. And that depends in large part on how long the owner expects to keep the engine in service. Will they trade equipment out after just three years or will they keep it and rebuild it?

"Our point of view," Cherrillo adds, "is to look at an oil change as cheap insurance. If nothing else, it provides an opportunity for a mechanic to see the vehicle and notice any problems early on."

Brian Jacoby, field formulation engineer for Castrol Heavy-Duty Lubricants Inc., agrees that the new emissions regs pose a question mark for extended drains.

"Due to the introduction of EGR in 2002," Jacoby remarks, "soot loading of the oil may increase by two to three times where it is now. And that means the oil must work harder to protect the engine.

"Specifically," he continues, "it will be more difficult to control viscosity. Soot makes oil more viscous, which in turn impacts its extended-drain capability. Dispersing soot is the major 2002 challenge oil must meet."

Jacoby explains that oil formulated for high soot dispersancy will help reduce deposits that shorten engine life and will help thwart filter plugging. Therefore, adequate dispersancy will help fleets use extended drain intervals with confidence.

He expects PC-9 oil will rise to the challenge, allowing fleets to maintain the extended drains they currently enjoy while ensuring engines are protected from soot loading. "The goal of PC-9," Jacoby states, "is to safely maintain 30,000- to 40,000-mile drains for EGR engines."

Thanks also to EGR, oil lubing 2002 engines will have to deal as well with higher levels of sulfuric acid in the crankcase, points out Dan Arcy, product manager for heavy-duty engine oils at Pennzoil-Quaker State.

"PC-9 oils will have to have three key features," Arcy says. "Along with better soot dispersancy, they'll need higher alkaline reserves, expressed as total base number (TBN), and better oxidation control or high-temperature protection.

"To keep extended drains where they are currently," he continues, "fleets will need a premium-quality oil. A lot of testing remains to be done but we believe the PC-9 deadline will be met - if closely."

According to Michael Ragomo, product advisor for ExxonMobil Commercial Vehicle Lubricants, "EGR will bring more acidic components into play, depleting TBN, the oil's alkalinity reserve, at a more rapid rate. There is also the potential for more particulate dropout into the crankcase. On top of that, the need to dissipate heat means PC-9 oil will need higher oxidation resistance."

More ash But there's more. Tom Olszewski, technical advisor for ExxonMobil Commercial Vehicle Lubricants, points out oil that may be required for EGR engines may produce more sulfated ash. He says higher ash content can cause crownland carbon deposits to form, which would be detrimental to engine life.

"While PC-9 will address soot-loading, corrosion and deposit factors, and TBN depletion," says Olszewski, "at the same time, customers will continue to push for extended drains."

Ragomo concurs that PC-9 doesn't address extended drains specifically. However, he points out that fleets might avoid having to establish two different drain intervals for pre-2002 and 2002 engines by moving to a higher-quality or "premium" oil specially formulated for that purpose.

"There's still uncertainty about where things will end up," cautions Olszewski cautions. "For one thing, the timetable for completing PC-9 is very tight. API licensing by June of 2002 is possible only if there are no more setbacks in developing and running the tests needed to establish the category.

"On the other hand," he adds, "PC-9 will be easier to complete than PC-10, which will involve engines fitted with catalytic aftertreatment devices and perhaps particulate traps."

Dick Patrick, heavy-duty product specialist at Citgo Petroleum Corp., raises a point that clouds the PC-9 picture a bit. "Based on side comments from engine makers," says Patrick, "it seems the amount or rate of EGR is still up in the air and may vary by OEM. From what we're hearing, as little as 4 to 5% of the exhaust gas may be recirculated - or as much as 17%.

Draining Issue "This affects oil quality because the more exhaust gas that's recirculated, the harder the duty cycle is for the oil," he continues. "And that could force fleets to reduce their extended drain intervals."

According to Mark Betner, Citgo's heavy-duty motor oil manager, the greater acidic conditions expected from EGR could lead to more corrosive wear.

"Fleet managers trying to optimize drains of 25,000 miles or more, as well as those after longer engine life, may need some better benchmarks," Betner remarks. "After 2002, it will be more critical for fleets to work with their lube suppliers to determine oil condition trends for their specific truck."

Overall, then, the consensus of the experts is that the demands posed to oil formulators by PC-9 will be met, and on time, if barely, for the arrival of the 2002 engines.

When it comes to the 2006 engines and the challenge of developing the PC-10 oil they'll need, the view of the future is less rosy.

Some oil engineers contend that not enough is known about the hardware that will be employed on 2006 engines to hazard a guess as to what impact that will have on the specifics of PC-10.

Others, willing to go out on a limb, figure enough is known at this point for the industry to start to get concerned about "backward compatibility" becoming an issue.

That ominous phrase is shorthand for the possibility that the oil formulation needed to protect 2006 engines will be so different from the CH-4 oil we know today (and the upcoming PC-9) that fleets will have to stock two different lubes to protect all their equipment equally.

Time will tell if that's the case. For now, the good news is that the oil industry is well on its way to completing the PC-9 category and has begun the spadework for PC-10.

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