On-highway diesel engines using selective catalytic reduction (SCR) to meet EPA2010 emissions standards will not require a new grade of engine oil, suppliers say.For most North American OEMs, according to oil experts, there will be no...
On-highway diesel engines using selective catalytic reduction (SCR) to meet EPA2010 emissions standards will not require a new grade of engine oil, suppliers say.
For most North American OEMs, according to oil experts, there will be no difference in lubricant needs for SCR, which works by mixing diesel exhaust fluid (DEF) with engine exhaust. This then flows through an SCR catalyst and reacts to form nitrogen and water vapour. DEF consumption will depend on the engine manufacturer, but expectations are that it can be about 1-3% of the diesel fuel consumed.
According to the Diesel Technology Forum ( www.dieselforum.org), SCR technology can reduce NOx emissions up to 90%, hydrocarbon and CO2 emissions by 50-90%, and particulate matter (PM) emissions by 30-50%, a win-win for both the trucking business and the environment.
By all accounts, the American Petroleum Institute-designated CJ-4 group of oils, which were formulated for the demands of EPA07 engines with exhaust gas recirculation (EGR) technology and diesel particulate filters (DPFs), should also be suitable for all 2010 engines.
“The recently launched CJ-4 category seems to be performing quite well in the EPA07 engines and is expected to do the same for the new 2010 engines. No new oil specification has been generated for the needs of the 2010 engines,” said Allan Murray, category manager for automotive/commercial and industrial engines at Petro-Canada Lubricants.
“Generally, the new CJ-4 products have been well-received by mixed fleets as this new spec’ is back serviceable. However, the use of lubricants that do not meet the CJ-4 specification would not be recommended for the 2007 engines and newer,” he said.
Dan Arcy, OEM technical manager for Shell Global Solutions (Shell Lubricants), said that while there are two different technologies in the post-2010 engine market, existing oils will work with both.
“Navistar is the one outlier using advanced EGR, which is basically higher levels of exhaust gas recirculation. Everyone else is going with SCR. In both cases though, the recommended oils will be the CJ4, API-recommended oils. I’ve been in the business over 20 years, working with heavy-duty engine oils. For 2010, this is the first time that oil hasn’t had to change to lubricate the new engines. So in one sense one of the real benefits is not having to worry about changing engine oils for the 2010 trucks. These oils are also backwards-compatible, and can be used on 2007 and earlier engines,” said Arcy.
The CJ-4 engine oils came out in 2006 with improvements in wear and deposit control, and restrictions on the amount of sulphated ash that accumulated in the particulate filters when the oil is burned off. The OEMs asked for limits to this sulphated ash, noted Arcy.
“Our tests have shown that SCR does not add any new requirements as far as oil properties are concerned,” said Gary M. Parsons, global OEM and industry liaison manager with Chevron Oronite Company (which develops, manufactures, and markets fuel and lubricant additives). “In fact, SCR is less restrictive than DPFs are. DPFs require low SAPS (Sulphated Ash, Phosphorous, and Sulphur) oils to prevent premature plugging due to ash-forming components,”
Drain intervals, DEF and fuel economy
For 2010 engines, required drain intervals will depend, as they usually do, on a variety of factors relative to the fleet’s operations, such as OEM recommendations, how much fuel is consumed, and the quality of the oil.
Parsons noted the use of SCR systems allows the OEMs to modify their combustion strategies to optimize their engines for fuel economy and “allow more engine-out NOx knowing the SCR system will take care of the NOx reduction in the exhaust aftertreatment system.”
“In those cases, EGR rates will be reduced from 2007 levels which may allow for extended drains,” he said. “Lower EGR rates should reduce soot loading, operating temperatures, and acid formation. All of those should lead to direction-ally longer drain intervals. However, operators do need to employ used oil analysis because nitration may become more of an issue than in the past. Nitration leads to nitric acids which will deplete the total base number (TBN) of the oil,” said Parsons.
Parsons noted that he has not heard of any specific scepticism regarding oil technology.
“The SCR/DEF OEMs are all recommending 35,000 to 60,000 mile drain intervals. Navistar, which is using ‘optimized EGR’ has recommended 25,000 mile drains,” said Parsons.
Shell’s Arcy said engine oil can also contribute to improved fuel economy with new or existing engines.
“With fuel pricing starting to inch up a little bit, fuel economy is definitely a topic of conversation. We see some of the OEMs starting to lean in that direction. From an oil standpoint, we can improve fuel economy with synthetics or semi-synthetics in the engine. Most are already using them in the driveline,” said Arcy.
“We have seen a 1.6% reduction in fuel use using a 10W30 in the engine. Some of these little numbers do add up. We see this as a trend. Volvo is factory filling with 10W30 right now. The synthetics offer better cold starting, and it is worth checking for fleets if this may be an option,” he added.
Fleets and owner/operators running APUs may also want to consider a 5W40 synthetic oil, Arcy noted, “because if the truck is going back and forth from a northern climate and then heading south, the engine on the APU must be able to start in extreme climates. Synthetics were designed to protect under extreme conditions, both extreme hot and extreme cold.”
With regard to diesel exhaust fluid and access to refills, fleets will have to decide the approach that works best for them, said Arcy.
“The fleets will have to decide whether they will top it up at the fleet’s terminal or have them top up on the road. It will mean extra equipment.
“If they’re terminalling it, they’re going to have to have it somewhere warm because diesel exhaust fluid will freeze. Those are things they are going to want to talk about with their supplier,” he said.
Are fleets prepared for 2010?
Increases in truck prices in both 2007 and 2010 related to more stringent exhaust emissions standards have made fleets aware of the extra equipment on the trucks.
“I believe that learnings from the EPA07 engine introductions were not lost on the 2010 engine introductions,” noted Murray.
“From what we have heard, the diesel particulate filters have proven to be very durable and most fleets have not accumulated enough mileage since 2007 to require a removal and cleaning of the DPF ash yet,” said Parsons.
He noted that the move away from API CI-4 PLUS to API CJ-4 was slow to begin with for a couple of reasons. “First, the number of post-2007 trucks in the fleet requiring API CJ-4 oil is relatively small, especially with the drop in new truck sales due to the downturn in the economy. The fleets have had good success with API CI-4 PLUS oils in the pre-2007 trucks and have little incentive to change to API CJ-4 until an appreciable number of post 2007 trucks are in the fleet. Second, until the start of 2010, the off-highway market is still allowed the use of low-sulfur diesel fuel (up to 500 ppm sulfur). API CI-4 Plus has a higher TBN and is better formulated to neutralize the higher levels of crankcase acids formed due to higher fuel sulfur levels.”
However, the switch to CJ-4 oils is gaining momentum, Parsons noted.
“Beginning in 2010, all diesel fuel has to be ultra low-sulfur diesel fuel (ULSD = 15 ppm sulfur maximum). Now that all the diesel fuel is ULSD, many of the on-and off-highway fleets can and will switch to API CJ-4 oils. In addition, many of the major lubricant marketers have discontinued the widespread availability of API CI-4 Plus oils in favor of API CJ-4 oils,” said Parsons.
With regard to any scepticism about the emergence and adoption of the 2010 engines, Parsons said th
at with additional costs announced by the OEMs for 2010 trucks (about US$8,000-$10,000 more than equivalent 2007 trucks), and with the slowdown in the economy and financing still difficult in some areas, purchasing new trucks is difficult.
“It remains to be seen if the diesel exhaust fluid infrastructure will be an issue for early adopters, but that is a concern. The OEMs such as Volvo, Daimler, and Cummins are all advertising up to 5% fuel economy gains of 2010 trucks versus 2007 trucks. That’s exciting to the fleets and will become an even bigger factor if fuel prices rise,” he said.
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