Black carbon (BC) is a major constituent of diesel-engine exhaust emissions. Aethalometer® was used in the measurements of the BC concentrations (with time resolution of 5 s) in the exhaust of a truck model 1995 Dodge RAM 2500 diesel pick-up equipped with an oxidation catalyst. The measurements were made from a chassis dynamometer during the acceleration, deceleration and cruise (constant speed) modes of the hot start of the MEC01 test cycle (version 7.0). Exhaust particles were collected in parallel on quartz fiber filters for elemental carbon (EC) and organic carbon (OC) measurement by the thermal-optical reflectance (TOR) method, and on Teflon® filters for gravimetric total particle mass (PM). Rapid acceleration was accompanied by corresponding instantaneous increases in BC emissions. Under wide open throttle acceleration (WOT), Aethalometer® BC concentrations peaked at 1.2 mg m-3, but reduced to only 0.03 mg m-3 under cruise conditions at 20 mph. These results show that it is possible to measure speciated diesel particulate emissions essentially in real time as a function of engine load and other operating conditions.
high-time; black carbon; BC; diesel engine; exhaust emissions
