测量区域对初级柴油尾气颗粒排放物的瞬态激光诱导白炽光测量的影响
Laser-induced incandescence can be applied to raw exhaust at the open tailpipe, or along the exhaust train using either an in situ optical cell or by extractive sam-pling to an external cell. While in situ measurements are preferable to avoid artifacts caused by extractive sam-pling, the experimental setup may be complex and thus more expensive to implement. In this paper we make a direct comparison of time-resolved in situ versus ex-tracted-sample measurements for rapid engine tran-sients of load and speed. In addition, we compare meas-urements for exhaust extracted from three different loca-tions: 1) at the turbocharger output 2) at the muffler entrance 3) at the muffler exit. The results show that extractive sampling sufficiently replicates in situ meas-urements obtained at the muffler entrance, and that rapid transients in soot concentration vary to a small but detectable degree with the measurement location.