Diesel engines are the primary power source for the medium and heavy-duty truck applications in the US. There is a wide range of regulatory developments being considered in the US that would impact the field of diesel engines and aftertreatment systems, such as the California Air Resources Board’s (CARB) low NOX standards and the extended durability requirement for aftertreatment systems. The proposed durability standards would require manufacturers to develop aftertreatment systems targeting up to 800,000 miles of full useful life (FUL) for Heavy heavy-duty (HHD) Application. Robust design and validation of aftertreatment systems is critical to ensure compliance with such stringent regulations. Several methodologies are being considered by the regulatory agencies for the compliance validation process, including the option of accelerated aging of the aftertreatment systems for a portion of the FUL. Performing FUL aging on an engine platform can be both technically challenging and resource intensive. To address these challenges, SwRI has developed a diesel fueled burner platform that could be used for accelerated aging and in-situ performance evaluation of aftertreatment systems for a wide range of engine displacements. Several SAE papers have been published on the burner performance characteristics and controls; however, burner particulate matter physical characteristics had not been addressed.
In this study, burner-out soot mass and solid particle number (PN) emissions along with particle size information were investigated over a range of steady state and transient operating conditions. Burner operation was tuned to achieve soot mass concentration varying from 0.94 mg/m3 to 38 mg/m3, and solid particle number concentration from 9.19e+05 particles/cm3 to 7.81e+07 particle/cm3. The geometric number mean diameter (GNMD) of the corresponding particle size distributions ranged from 14 nm to 58 nm. The physical characteristics of solid particles suggest that the burner-based platform can be used to generate particle emissions representative of compression ignition diesel engines. The development of such a robust burner-based technological solution coupled with detailed understanding of its particle emissions enables this technology to serve as a powerful and cost-effective alternative to engine-based development, validation and aging of next generation diesel exhaust aftertreatment systems.