Post-field evaluation of diesel particulate filters

The paper discusses the laboratory performance evaluation of diesel particulate filters (DPF) after a long-term field trial at INCO's Stobie underground mine in Sudbury. These DPFs, used at the mine with heavy-duty production and non-production vehicles, were evaluated at the Diesel Emissions Research Laboratory of CANMET-MMSL in Ottawa. The laboratory evaluation included emissions bench testing, particulate characterization, and DPF inspection for internal and/or external damages. The laboratory testing utilised three types of protocols, (1) ISO 8178-C1 8-mode, (2) 3-mode test cycle, and (3) the SAE J1667 transient snap acceleration. During testing, measurements were made for gaseous emissions (CO, CO2, NO, NOx, and THC), and particulates by mass and size, and PAS (Photoelectric aerosol sensor) by using a NanoMet Instrument. The DPFs were inspected by visual, x-ray and borescope methods. All the DPFs tested significantly reduced NO2 (varying from 38% to 67%) and diesel particulate matter (greater than 85% on mass basis, greater than 93% on number basis, and greater than 74% based on the PAS measurement). The lowest efficiency was measured for the HD213A DPF, perhaps due to some damage in mine-field trials. All DPFs significantly reduced SOF, PAH and sulphates. In general, laboratory measured DPF efficiencies are similar to or a little lower than those measured during field trials.