Of CJ-4 and ULSD

Despite some ominous predictions, some things actually did go well in the fleet transportation industry in 2007.

A year ago, a lot of fleet maintenance managers were worrying about the 2007 medium and heavy-duty engines. Would the higher underhood temperatures created by the 2007 emissions systems cause a meltdown of tanks, belts and hoses? Would the costs of the new engines price some smaller fleets out of the new truck business? Would the regeneration cycles needed to clean accumulated soot out of the new diesel particulate filters (DPFs) disrupt duty cycles and maintenance intervals?

While none of these have proven to be catastrophic to the industry, none have actually been swept aside, either. In other words, one year into the era of ‘07 engines, no news is not necessarily good news.

I was recently reminded that there were some spots of good news in 2007, however. Some new diesel engine advancements went quite well, thank you very much, and promise to continue into 2008 without causing much of a stir.

On a recent visit to our editorial offices, Stede Granger and Walt Silveria of Shell Lubricants talked at length about how the new CJ-4 diesel engine oil and ultra-low sulfur diesel fuel (ULSD) have been seamlessly integrated into the trucking industry.

The Shell folks describe the development of CJ-4 engine oil as the biggest re-engineering of their product in the company’s history. In other words, there was a lot riding on this new reformulation, and they had to get it right.

The 2007 emissions requirements, of course, necessitate a new brew of diesel fuel with only 15 parts-per-million of sulfur (as opposed to the previous level of 500 ppm), as well as a diesel particulate filter (DPF) aftertreatment device. The new engine oil was needed to help maintain the durability and performance of the DPF.

Interestingly, engine oil consumption has gone down with the ‘07 engines, Granger says, so fleets will have to top off the engine oil less then they did with pre-’07 engines. While that’s a good thing for the engine, it means that the oil itself spends a longer time in the engine and so it has to be that much more durable.

According to Granger, CJ-4 engine oil was designed to handle increased levels of soot generated by the exhaust gas recirculation (EGR) system, but it has affected system performance in other ways as well.

Lower sulfur levels in the system mean that OEMs have not had to reduce engine oil drain intervals. In fact, as you’ll read in our cover story (beginning on page 6), at least one fleet is already looking to extend its drain intervals, although Granger cautions that fleets must have an oil analysis program in place before considering this step.

Some in the industry have complained that CJ-4’s TBN numbers would be too low, but Shell’s studies, Granger said, have shown the opposite.

When asked if there would be a new “CK-4” engine oil 2010, Granger and Silviera said that they don’t anticipate a new blend being needed for the next level of EPA emissions standards. That doesn’t mean we won’t see a tweaked formulation that could be given a “CJ-4+” designation.

2010 standards could cause fleets to take a look at CJ-4 synthetic products, Granger said. Shell’s coming synthetic product will be engineered for better cold weather starting, engine protection and deposit controls, and may even bring about a fuel economy improvement.

ULSD is also a success story for the industry, although it has hit a speed bump or two along the way to respectability. As Granger pointed out, there have been problems with winterizing ULSD, and one of the fleets profiled in our cover story has concerns about consistent quality in the ULSD fuel supply.

According to Silveira, the jury is still out on the effectiveness of biodiesel blends to maintain the lubricity of ULSD. He cautioned that biodiesel could break down CJ-4 oil, and suggested that fleets using higher blends of biodiesel with ULSD should test regularly to ensure that there is no fuel dilution taking place.

Has your experience with CJ-4 and ULSD fuel been good or bad? We’d like to hear from you!

Correction: In the September Show-case issue, we misidentified the Mobile Air Conditioning Society’s Web site. The proper address is www.macsw.org

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