Some clean diesels of the 2000s have been disruptively unreliable and most are discouragingly expensive, but performance has improved as manufacturers try hard to fix them, said fleet executives at last week's annual meeting of the Technology & Maintenance Council.
In an "EPA 2007/2010 Engine Report Card," five executives cited extensive data from tens of thousands of truck-tractors using diesels that meet a series of increasingly stringent exhaust emissions limits that began production in late 2002.
All expressed frustration with the engines' troubles and lack of support in the field, but praised manufacturers for working alongside them in trying to solve the problems.
The execs reiterated what colleagues had said in previous "report card" presentations at TMC meetings: Problems began with 2002/2004-spec engines with exhaust gas recirculation and got worse with 2007 versions that use EGR plus diesel particulate filters.
2010-type engines, using the previous equipment plus urea injection, are somewhat less troublesome and get better fuel economy.
Caterpillar, Cummins, Detroit, Paccar and Volvo-Mack diesels were covered in the presentations. Navistar diesels, the only brand not using selective catalytic reduction for 2010, were not. Only one fleet reported having Navistars; the exec did not include them in his remarks.
That exec was Steve Duley, vice president, purchasing, for Schneider National, headquartered in Green Bay, Wis., who showed the largest set of operating data. He said the fleet has about 9,800 tractors with '04, '07 and '10 series diesels, mostly Detroit Series 60s and DD15s but with a smattering of others for "benchmarking" purposes.
"Our expectations are lower" for the subject engines because they have averaged 4% more work orders and visits to the shop and 4% more tows, often following appearance of fault-code warnings in the tractors' instruments, he said.
There have been many problems with getting parts and special tools, and there have been some malfunctions and failures in the equipment that handles diesel exhaust fluid in the 2010 diesels. The DEF itself is readily available at moderate prices.
"Warranty challenges" occur with delayed and progressive damage to DPFs, and technicians sometimes find errors in settings for engine operating parameters when new tractors are delivered.
"Drivers like the power and responsiveness of the engines, but they struggle with dashboard codes," Duley said. It's especially confusing for drivers who went from '04-equipped trucks, which had few codes to display, to 2010s, which have many.
Drivers each needed 1 hour of training to understand the engines, mechanics needed 4 hours each, lead mechanics each required 35-40 hours of training, and call center people needed 2 hours each.
Since 2002, the weight of a Schneider tractor is up by 1,200 pounds, and 400 of that is for the SCR urea injection equipment. Cost-per-mile numbers are down with the latest engines, but overall Schneider's CPM is up by 10.5 cents since '02.
Brian Baker, a fleet maintenance specialist for FedEx Freight, said the fleet has about 3,450 EPA-'04 and '07 diesels. Some are Volvo D13s and the others '07-type Cummins ISXes, plus '10-spec diesels.
Reliability of the '07s is 33% worse than the '04s but they get 1.95% better fuel economy. EPA-2010s are 60% more reliable than the '07s and get 5.87% better economy. The cost to purchase tractors is up 27.4% since 2004, he said.
Mike Moynahan, assets and procurement manager at H.E.B. Grocery, a regional chain based in San Antonio, said his 2007-spec diesels suffer 8% more work orders and cost 28% more to maintain compared to pre-'07s.
Problems include plugged EGR coolers, a high number of DPF regenerations (when they're cleaned of soot by heating), and grief with aftertreatment equipment in general.
"Supplier response was slow" in fixing the engines, Moynahan said. "They're learning like us -- the '07s are still not fixed-- but they're right beside us," he said of factory representatives.
Reliability of the '07s has been so bad that "some have run only 300,000 miles because they're down so much," Moynahan said. Downtime has averaged four days, with some tractors down as long as six weeks. "That's terrible, when you pay as much for trucks as we do," he complained.
Lack of reliability affects deliveries to stores, equipment utilization, and drivers running out of hours.
"Our drivers stay a long time (the average is 27 years) so I can't say that they've quit over this, but some drivers have retired early." The grocery fleet has to keep spare tractors because of so many breakdowns.
However, 2010 engines are much more reliable and are getting better fuel economy. MPG numbers are up, but some of that is due to new automated mechanical transmissions, which operate the engines better, he said.
Also, engines run slower by 200 rpm, and the 2010 tractors have a 6x2 axle configuration with only one drive axle instead of the traditional 6x4 with a less-efficient live tandem.
Purchase costs are up 30% since pre-EGR engines, Moynahan said, which is about 6-8% per year. "We were told they would cost very little, but they have cost a lot." But he ended his presentation graciously by again noting, "Suppliers are in the trenches every day with us, trying to fight these problems."
Duane Lippincott, a fleet manager at United Parcel Service in Atlanta, also reported difficulties with EPA-'07 diesels and improvements with the 2010s. UPS runs Cummins ISX, Detroit Series 60 and Mack MP engines, totaling about 5,600 day cab tractors with single rear axles that have covered 1.3 billion miles.
The '04 and '07 engines account for more breakdowns than their population in the fleet, and their fuel economy is worse by 3-4%, Lippincott said. The 2010s are up 4.2% in economy, but are of smaller displacement.
All maintenance costs are up, including DPF cleaning since '07, plus higher parts prices, expensive road failures, higher-priced CJ-4 motor oil, costly EGR work, and the addition of diesel exhaust fluid and storage tanks for it.
As for life, the 1-million-mile engine had been achieved prior to the 2000-2010 decade, but "we don't see 1 million miles anymore," he lamented.
UPS figures that since 2000, the cost of a new tractor has risen 115% -- 40% for '04 and 64% for 07, and the rest for '10. "That's a huge increase, and my salary certainly hasn't gone up that much," he said.
"In all cases, the manufacturers are working hard to resolve the issues, although it takes time. But "as a company and an industry, we cannot keep absorbing these costs."
Frank Nicholson, vice president of maintenance at TransAm Trucking, Olithe, Kan., had previously complained of serious problems with '07-spec Caterpillar Acert diesels. At this meeting he had an encouraging update: Only about 2% of his 692 Cat-powered Kenworth tractors are now down at any one time. This was due to strenuous efforts by his people plus repairs, re-evaluations and frequent software updates by Cat representatives.
Better yet, the 533 2010-spec Paccar MX diesels are doing well - "excellent compared to the '07s" - though they suffer sensor failures and need software updates. The 2010s are 10.5% more fuel efficient than pre-'07 diesels, Nicholson said, but some of that is from aerodynamic fairings, wide-base-single tires and other improvements.
DPFs have to be serviced frequently and Nicholson now includes them in his preventive maintenance items. So PM costs are up 200% vs. pre-'07-engined tractors. Tow charges are up 78%, but are due to engines as well as other factors. The price of a new tractor has risen 47.6% since 2006, he said.