Like other 2010 selective catalytic reduction (SCR) systems, Detroit Diesel’s BlueTec technology will require diesel exhaust fluid (DEF), a solution of two-thirds pure water and one-third automotive-grade urea, to treat exhaust gases downstream of the engine.

The DEF reacts with smog-forming nitrogen oxides (NO_x) in an SCR catalyst, reducing the NO_x released into the air into nitrogen and water. The new BlueTec emissions control system requires virtually no changes to Detroit Diesel’s base engines—meaning those base engine parts are already available and the service network is already trained to support them.

More than 2,500 dealers, distributors, truckstops and retail outlets in North America are committed to carrying DEF, reducing concerns about availability. Vehicles equipped with Detroit Diesel BlueTec SCR technology will require DEF refilling about every 5,000 to 7,000 miles per 23-gallon DEF tank under typical highway duty cycles.

In addition to the NO_x reduction, the Detroit Diesel BlueTec engines will offer up to 5% diesel fuel economy improvement over current DD15 engines, and up to 3% net improvement for the BlueTec emissions technology. When compared to non-SCR technologies planned for use in 2010, the Detroit Diesel BlueTec technology will deliver even greater fuel economy advantage.

Detroit Diesel says that three factors contribute to the optimized fuel efficiency: base engine-out NO_x levels, DPF regeneration intervals, and exhaust back pressure.

BlueTec treats the exhaust gases outside of the engine and allows the in-cylinder combustion process to be fully optimized for peak thermal efficiency via refinement of fuel injection timing and exhaust gas recirculation (EGR) rates. This, in turn, also results in reduced engine heat rejection and reduced stress on the cooling system.

The efficient combustion process of BlueTec equipped engines is also much cleaner and generates extremely low levels of engine-out PM. These low levels of engine-out PM, coupled with favorable NO_x/PM ratios and Detroit Diesel’s all-new, robust DPF material, significantly prolongs the DPF active regeneration interval in 2010. Moreover, DDC’s BlueTec technology predominantly utilizes a low temperature process for DPF regeneration and limits exposure to high temperatures to only once in several thousand miles for typical heavy-duty highway applications.

BlueTec will also subject the aftertreatment system to less thermal stress and fatigue compared to other systems. Reduced exposure to high temperatures also minimizes the aging of the catalyst coatings, thus retaining the BlueTec system’s high performance and efficiency over its lifetime.

Detroit Diesel will offer BlueTec technology in two packaging options: a one-box and a two-box configuration. In addition to providing for space optimization and adaptability to a wide variety of truck applications, the proprietary Detroit Diesel BlueTec one-box option uses a unique design that reduces the exhaust gas flow restriction, resulting in less exhaust back pressure and therefore improved fuel economy.

Detroit Diesel expects that the majority of its customers will opt for the one-box configuration, which houses all the exhaust aftertreatment components is a single unit. At the TMC press conference, Detroit Diesel showcased its one-box configuration in combination with the DD15 and aerodynamically-designed Cascadia truck.