ORLANDO, Fla. - The push for cleaner truck exhaust came at an obvious cost. FedEx Freight paid an average of $4,000 extra for post- 2002 engines that reduced NOx with technology such as Exhaust Gas Re...
April 1, 2008
Technical Correspondent John G. Smith
ORLANDO, Fla. –The push for cleaner truck exhaust came at an obvious cost. FedEx Freight paid an average of $4,000 extra for post- 2002 engines that reduced NOx with technology such as Exhaust Gas Recirculation (EGR) systems. Maintenance needs also increased, and fuel economy plunged as much as 16%.
But things have improved. The maintenance costs -while still higher than those that were faced before 2002 -are not as frightening as they once were. The exhaust- cleaning components have been refined. Some of the sacrificed fuel economy has even been regained, and drivers love the improved acceleration that comes with the equipment.
The fine-tuning of the engines’ Electronic Control Modules ultimately delivered fuel economy that was within 3% of the numbers seen prior to the equipment changes mandated by the US Environmental Protection Agency, says Dan Umphress, managing director of maintenance solutions at FedEx. The 2007 engine designs with Diesel Particulate Filters have performed just as well.
“Electronic groups of the manufacturers are very busy,” he told a crowd of maintenance managers at recent Technology and Maintenance Council meetings. “We were most glad that it wasn’t worse.”
Some fleets still have a role to play if they want to recover that lost fuel economy. Umphress, for example, says maintenance managers need to keep a close eye on fuel maps.
Most FedEx tractors are 4×2 day cabs that typically pull a pair of pup trailers for an overall Gross Vehicle Weight of 66,000 lb.
The problem is that the default programming on a new engine tends to be set up for a truckload tandem configuration that has a Gross Vehicle Weight of 80,000 lb.
“You can get optimum efficiency by working with an engine supplier and matching fuel maps to your duty cycle,” Umphress says. “If there’s anything outside the box, you will need to work closely with suppliers.”
The good news is that some of North America’s largest fleets are reporting better working relationships with those who supply the engines in the first place.
“Recalls were handled very swiftly,” says Tom Newby of the Old Dominion Freight Lines, noting how one supplier to his 5,000- tractor fleet has assigned a single point of contact for warranty claims. “It’s one of the best things that happened during these times …We started to get the personalized communication back.”
Granted, the fleets and manufacturers also had a lot to talk about.
When the first post-2002 engines were introduced, FedEx was plagued by troublesome turbos, EGR valves, coolers, sensors and hose clamps.
Schneider actually thinks the gross maintenance costs for its 2004 engines will be 62.8% higher than the cost of maintaining equipment that was purchased be- fore the rules were in place.
But again, the equipment has improved. When tracking the maintenance on engines built since 2005, Schneider’s Steve Duly has found that gross maintenance costs are 18.2% higher than those linked to pre-EGR engines.
Schneider’s issues involving EGR valves, bellows pipes, and intake throttle valves have largely been addressed.
That experience has carried over into the 2007 engines that are equipped with new Diesel Particulate Filters.
“The base engine itself, independent of the aftertreatment, is performing quite well,” Duly says, adding that exhaust systems are more durable.
There are still some issues, however. The larger cooling system required a change to fan mounts and engine mounts, and there is a different turbo and coalescing filter to consider. The fleet has also needed to address challenges around the cooling of the transmissions, and larger alternators have been required.
Ultimately, the host of additional equipment has added to overall weights as well. The post-2007 Schneider trucks are 350 pounds heavier than their predecessors, and Old Dominion needed to update gear ratios and reposition the fifth wheels to compensate for the extra mass that it faced.
Challenges with the Diesel Particulate Filters haven’t been limited to the extra weight, either.
“We have a good, safe regeneration cycle now,” Duly says, “but it is definitely not optimized for fuel economy.”
If there is one common complaint, it seems to involve the fact that drivers need to control the regeneration cycle more often than expected.
“We thought the manual switch would sit there any never be touched,” Umphress says. That hope ended in the first few days. “We ended up with more driver training and coaching than we thought we would.”
The switches themselves have caused another challenge, Umphress says, referring to one model of truck that includes a toggle switch to bypass the regeneration cycle. The problem, he says, is that there is nothing to remind drivers that it has to be flicked back into place. “A better solution would be some sort of momentary switch.”
Similar challenges have been experienced at Schneider, where engines ultimately de-powered because drivers ignored the related warning light. The answer has come in form of cab decals explaining what the lights mean.
It all adds up. Every Schneider driver now needs an hour of extra training, while lead mechanics receive up to 40 hours of related training.
General mechanics need an extra five hours of study time, while maintenance call centre associates need another two hours to focus on questions specific to the emission systems.
New engines, old oils
Despite all the changes, these fleets admit that one thing has stayed the same – their oils.
There may have been a massive effort to introduce Ultra Low-Sulfur Diesel (ULSD) fuel and a new CJ-4 oil to protect the Diesel Particulate Filters, but these maintenance teams have opted to stick with the previous generation of oils. Schneider has even maintained its current drain intervals of 7,000 miles per quart (a little under 12,000 km per litre) with the help of a regular oil analysis.
Granted, the decision presents a few unknowns. None of the fleets have accumulated the mileage needed to test the impact on Diesel Particulate Filters, which could be fouled by the higher ash levels in a CI-4 fluid.
Schneider’s largest pool of 2007 engines comes in the form of 48 Freightliner C120s equipped with Detroit Diesel Series 60 engines, but they have only accumulated an average of 260,000 km each.
The fleet doesn’t expect the filters to require servicing until they’re on the road for at least 480,000 km.
The only change expected in the short term could come in the form of a custom-blended oil that will offer some of CJ-4’s properties, but at a lower price.
Says Newby of the Old Dominion fleet: “We’re going to ride it out and see.”
Then there is the question of when the Diesel Particulate Filters will require their first cleaning, and who will do the work. For its part, FedEx plans to clean its own equipment in-house. Each fleet is still considering its strategy.
In the meantime, drivers are enjoying the ride.
“Our drivers noticed a considerable acceleration improvement,” Umphress says of the trucks purchased since 2002. “They call them hot rods.”
Of course, the fleet also opted to move up from the 11-litre displacements that it had bought before 2002, largely because buyers thought the extra airflow might be helpful.
“New technology has made that ideal obsolete,” he admits, “but once you go up in engine size, it’s a one-way ptrip.”
Looking specifically at the 2007 engines, Newby agrees that the torque curves are unchanged. The hot rods remain.
The biggest unknown may involve how much future buyers will like the trucks. FedEx, for example, has yet to re-sell any of the trucks that it bought with post-2002 engines. Newby has a mere 200 of the 15-litre EGR designs that have crossed the million-mile threshold.
Duly admits that Schneider couldn’t recover all of the additional costs when it sold some of its used equipment. “But we also did not receive a penalty,” he says.