Michael J. Cunningham

Time-Resolved Measurements of Emission Transients By Mass Spectrometry

Transient emissions occur throughout normal engine operation and can significantly contribute to overall system emissions. Such transient emissions may originate from various sources including cold start, varying load and exhaust-gas recirculation (EGR) rates; all of which are dynamic processes in the majority of engine operation applications (1). Alternatively, there are systems which are inherently dynamic even at steady-state engine-operation conditions. Such systems include catalytic exhaust-emissions treatment devices with self-initiated and sustained oscillations (2) and NOX adsorber systems (3,4,5). High-speed diagnostics, capable of temporally resolving such emissions transients, are required to characterize the process, verify calculated system inputs, and optimize the system.