Meeting Future NO<sub>X</sub> Emissions Over Various Cycles Using a Fuel Burner and Conventional Aftertreatment System

<div class="section abstract"><div class="htmlview paragraph">The commercial vehicle industry continues to move in the direction of improving brake thermal efficiency while meeting more stringent diesel engine emission requirements. This study focused on demonstrating future emissions by using an exhaust burner upstream of a conventional aftertreatment system. This work highlights system results over the low load cycle (LLC) and many other pertinent cycles (Beverage Cycle, and Stay Hot Cycle, New York Bus Cycle). These efforts complement previous works showing system performance over the Heavy-Duty FTP and World Harmonized Transient Cycle (WHTC). The exhaust burner is used to raise and maintain the Selective Catalytic Reduction (SCR) catalyst at its optimal temperature over these cycles for efficient NO<sub>X</sub> reduction. This work showed that tailpipe NO<sub>X</sub> is significantly improved over these cycles with the exhaust burner. In certain cases, the improvements resulted in tailpipe NO<sub>X</sub> values well below the adopted 2027 LLC NO<sub>X</sub> standard of 0.05 g/hp-hr, providing significant margin. In fact, near zero NO<sub>X</sub> was measured on some of these cycles, which goes beyond future regulation requirements. However, burner operation on the tested cycles also resulted in a CO<sub>2</sub> increase, indicating that a different burner calibration strategy, or possibly an additional technology, will be needed to achieve lower CO<sub>2</sub> emissions.</div></div>