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NOx emissions limits for commercial trucks will be drastically reduced in the United States and Europe later in this decade. The most recent Euro VII proposal suggested that pre-heating of the aftertreatment system with a diesel burner may be needed to meet a new low-NOx limit. Pre-heating serves to prepare the SCR catalyst so that it can begin to convert NOx almost immediately after the engine is started. This is particularly important for an engine that is not equipped with exhaust gas recirculation to reduce engine-out NOx. This study considered a burner installed between a 12.4 liter engine and an appropriately-sized in-line DOC/DPF/SCR aftertreatment system. Initially, a wide range of burner and air pump operating conditions were examined to determine the maximum fueling rate and corresponding air flow rate necessary to complete combustion and to convey the resultant heat downstream to the aftertreatment components.

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 NOX reduction. This work showed that tailpipe NOX is significantly improved over these cycles with the exhaust burner.