Novel technique to reconstruct instantaneous heavy-duty emissions

Abstract

Transient vehicle emissions, as measured in test cells or by on-board systems, do not precisely reflect the emissions at the exhaust because the instantaneous emissions are dispersed in time by the sampling and analyser systems. With increasing demand for accurate emission measurements to optimize engine controls and for atmospheric inventory models, research effort has been directed at compensating for measurement distortions by the emissions analyser system. This paper presents a new procedure, known as the modified deconvolution technique, which may be employed for the reconstruction of instantaneous emissions signals. The method was applied to revising mass rates of emissions as a function of speed and acceleration for the case of a transit bus. This revision (or reconstruction) led to a higher range of emissions rates and, for most high-power speed-acceleration bins, the mass emissions rate was increased. For bins with high deceleration, emissions rates were reduced.