Tim Shick, director of marketing, for the Navistar Engine Group, says about 40,000 Advanced EGR 2010 engines have been produced, including 12,000 MaxxForce 13 and 18,000 MaxxForce DT engines, with the balance lower volume engines.
None of the manufacturers have found any significant engine issues or problems. A few reported some minor controls and calibration issues with the very earliest of engine deliveries but these were quickly resolved.
“The only real issue we’ve experienced is the collection of empirical data on engine performance because we’ve had so few problems,” says Mack Trucks’ McKenna. “We actually have to ask our dealers and customers to upload logged vehicle data for analysis in support of, and validation of, our performance predictions.”
“Measured by reported faults, this has been Volvo Trucks’ most successful engine introduction,” notes Saxman of Volvo Trucks. “Much of our success can be attributed to our No Regen strategy, which uses only NOx (nitrogen oxide) for passive regeneration of soot from the diesel particulate filter. Because we’re not using fuel to regenerate soot, temperatures are much lower.
“Our most ‘senior’ EPA ‘10 engine now has well over 300,000 miles in all sorts of conditions and we’ve had no problems.”
EGR (exhaust gas recirculation) is an emissions reduction technique that works by re-circulating a portion of an engine’s exhaust back to the engine cylinders and burning off excess pollutants. Navistar is the only engine manufacturer to use EGR to meet 2010 diesel engine emission regulations.
The other manufacturers use selective catalytic reduction (SCR). SCR uses a urea-based diesel exhaust fluid (DEF). Small quantities of DEF are injected into the exhaust upstream of a catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide.
“We’ve been pleasantly surprised about the lack of issues relative to the DEF systems,” says Schaeffer of the Diesel Technology Forum. “As far as we know, there are not any supply issues with DEF or its availability in the first full year of use, and that’s pretty impressive going from none anywhere, to adequate supply in about three years.”
Problems with diesel exhaust fluid systems have been a non-issue since early 2010, adds Williamson of Daimler Trucks North America. The industry as a whole stepped up and answered the call for a DEF infrastructure. “There are over 3,500 locations across North America where drivers and fleets can purchase diesel exhaust fluid.”
Adds McKenna of Mack Trucks: “The introduction of DEF has gone smoothly and is widely available at affordable prices.”
All of the engine manufacturers say they have been very pleased with performance of their aftertreament systems and have not had any noteworthy issues. Each stressed the importance of having the system’s diesel particulate filter (DPF) serviced at regular intervals. “A dirty DPF still ‘breathes,’” says Saxman of Volvo Trucks, “but it’s more effective if kept clean.”
Both EGR and SCR emissions technologies utilize DPF technology to decrease particulate matter (soot) emissions.
Paccar’s Freitag says many of the issues with aftertreatment systems can be traced to drivers not understanding the DPF status lights for regeneration activities.
Basically, DPF technology works by employing a honeycomb ceramic structure with a series of alternate channels plugged at opposite ends. The diesel exhaust gas is forced through the open end of each channel.
The plug forces the soot particles against the porous channel cell walls to burn off there and allow only gases like steam and carbon dioxide (CO2) to pass through to the neighboring exit channel.
Highway driving and high engine load results in lower accumulations of particulate matter (PM) and high exhaust temperatures. A lot of idling and low speed/low engine load creates more PM, causing soot to build up in the DPF. Successful thermal regeneration clears the DPF of all the soot.
There are two types of thermal regeneration: passive and active. Passive regeneration happens automatically during vehicle operation when the heat of the exhaust burns off the soot.