TMC issues scorecard on 2007 diesel engines
Mar 1, 2008 12:00 PM
“The torque curves on the 2007 compliant engines are basically the same as the pre-2007 engines, said the company's Newby. “The drivers love them because of the acceleration benefit.”
As for fuel mileage, pre-2007 13-liter engines average 6.7 to 6.9 miles per gallon; the 15-liters, 6.3 to 6.5 mpg. With the 2007-emission compliant diesels, all with less than 100,000 miles, the 13-liters average 6.4 to 6.8 mpg; the 15-liters, 5.9 to 6.1 mpg. Fleet speed is governed at 68 mph.
Newby said drivers are trained on the new 2007 engines and their emissions equipment. Decals explaining the exhaust aftertreatment system are installed in all trucks.
Technicians are trained on servicing the new engines. A special training module was designed specifically for this purpose.
Old Dominion Freight Line added specific 2007-emission engine PM checks to its preventive maintenance forms, “making the whole PM process more productive,” Newby noted.
Steve Duley of Schneider National said the new 2007 emission engines required a number of vehicle specification changes to accommodate the new engines. These included a larger, engine-mounted radiator; fan blade and fan shroud; different engine mounts and isolators; space for the aftertreatment devices; electrically controlled variable geometry turbo; crankcase vent coalescor; and a change in the type of transmission oil cooler. This resulted in a weight increase of 350 pounds.
With regards to vehicle service, he reported no change in the oil drain interval, and lowered oil consumption — approximately 7,000 miles per quart. The fleet has experienced up to a 2 percent loss in mpg due to regeneration of the diesel particulate traps.
Schneider National's frequency of repair on its 2007 emission engines is nearly five times that of the pre-2007 engines. Vehicle downtime has increased 20 percent and towing up 15 percent.
As for fuel economy with the emission engines compared to pre-emission models, the 2004s had a 4 percent loss in mpg; the 2007s a 5 percent loss.
The carrier's life-to-date gross maintenance costs (total maintenance less accidents and tires) for its 2004 EGR engines is 62.8 percent above pre-EGR models. The one-year gross maintenance costs for its 2007 emissions engines is 282% above pre-EGR engines.
In terms of the total cost of emission compliance since October 2002, Duley said Schneider National is paying 8.2 cents per mile, up from 6.7 cents per mile, over the six-year life of its tractors.
Like FedEx Freight, the carrier has also had numerous problems with the various components of the exhaust aftermarket system.
Schneider National has developed training on the 2007 emissions engines for drivers, technicians, and emergency maintenance (call center) personnel. The fleet also has cab decals in all its trucks that explain operation of the exhaust aftertreatment systems.
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