4 Big Fleets Talk About '02 Engines

This has wiped out 10 years of fuel economy improvements.

Jim Winsor
Executive Editor

      During "Emissions Summit II," part of the recent Technology and Maintenance Council's annual conference, representatives from four mega-fleets discussed fuel mileage and maintenance issues with their new low-emission engines.
      Spokesmen for Schneider National, U.S. Xpress, FedEx Freight and Ryder shared their experiences to date with the '02 diesels. Collectively, the four fleets represent 80,000 Class 8 trucks and tractors.
      Steve Duley, vice president of purchasing for Schneider, said his firm now has several hundred post-'02 engines in its 9,000 tractor fleet with many more on order. Only a handful have more than 200,000 miles - not enough to learn if there are durability problems.
      "We've torn down one 12-liter Detroit Diesel at 250,000 miles and everything looked pretty good," he said.
      Schneider's average fuel mileage is off between 3% and 5% and "this has virtually wiped out the past 10 years of fuel economy improvements we gained," Duley said. Operating costs are running two or three cents more per mile than pre-'02 engines for a total projected additional cost of $15,000 per tractor during the 700,000 to 800,000 miles tractors remain in the Schneider fleet.
      Marty Fletcher, director of technology and training for U.S. Xpress, said his fleet's experiences were similar. Between engine brands, fuel mpg is off as much as 9%. U.S. Xpress is a major user of automated manual transmissions and Fletcher said there have been problems in the way engine ECUs "talk" to transmission-shifting logic when an engine sensor reads higher than usual turbocharger temperatures. He said the engine ECU may derate the engine horsepower to help lower turbo temps when pulling a grade, often surprising drivers. If this happens suddenly, the transmission logic isn't sure when to shift - or whether to shift at all. Drivers think there's a failure.
      Fletcher says hours - and even days - have been spent trying to troubleshoot the perceived failure. Often, he says, once the engine temp has returned to normal, the ECU has restored the engine power. Fletcher asks, "Do engine OEs really need to be so conservative about when their engines Ôderate'? We still need plenty of help with our '02 engines, and we need our suppliers to stay with us."
      FedEx Freight is an LTL carrier with 9,130 tractors - 758 of them with '02 low-emission engines. Highest mileage is 175,000. Dennis Beal, vice president of physical assets, said the fleet experienced an initial fuel mileage drop of 15% during the first 50,000 miles, after which fuel mileage "improved" to 4% but started dropping again after 75,000 miles. He had no explanation for this phenomenon. He said the duty cycle in LTL service is much harder on fuel mileage than truckload carriers experience. He's expecting some improvement in mpg as manufacturers upgrade engine ECUs and also alter axle ratios. And, Beal said, FedEx Freight has experienced failures with sensors, EGR valves, EGR coolers and injectors. "No huge horror stories, but lots of pain and extraordinary costs," he said.
      Ryder's issues were similar to the others but compounded by operating 800 shops. "Getting technical training to thousands of mechanics covering several brands of engines is difficult and time-consuming," said Jim Salas, director of maintenance and field support.
      Looking ahead, the four speakers shared their concerns about likely increases in tractor prices for '07. Figures as high as $20,000 were mentioned. This comes on the heels of the $3,000 to $5,000 increases on today's equipment with low-emission engines.
      Exhaust aftertreatment will be required for the first time to trap exhaust soot and other particulates. And EGR engines with increased cooled exhaust gases will require increased cooling capacities and chassis changes. Higher injection pressures up to 30,000 psi are also in the works.
      The offsetting good news is that there should be no further fuel penalties for '07 and, in fact, a good possibility of regaining much of the lost fuel economy with the post-'02 engines.