A Soot Generator for DPF Qualification Studies

Diesel vehicle applications are being tasked with increasingly stringent particulate emissions regulations. These regulations will require the use of Diesel Particulate Filters (DPFs). Prior to on-vehicle studies, DPF qualification studies are performed in laboratory bench reactors. In order to provide representative performance data, these studies require the testing of samples loaded with carbonaceous soot particles. A new soot generator, utilizing a pressure controlled propane flame, has been designed and built for this purpose. Soot production rates are on the order of approximately 8 mg/min at a concentration of 180 mg/m³. This allows 8 inch long cores to be loaded in 1 hour to soot concentrations encountered in typical vehicle operation. The soot generator allows for the selection of two distinct size distributions similar to typical diesel exhaust: a 57 nm peak and a 76 nm peak. Other peak locations, in the range of 40 to 120 nm, can be obtained with slight adjustments to the hardware. This paper describes the construction and operation of this new instrument and presents validation data. Checks of linearity, particle size distribution, and mass production rates will be presented. Additionally, regeneration studies of loaded samples show that decreasing the size of particles results in increased pressure drops across DPFs as well as less efficient combustion of particles.