Measuring Error of Exhaust Smoke Density due to the Variations of Pressure and Smoke Density

Abstract

This paper deals with the problems in the sampling procedure of smoke density measurement concerning the regularity of smoke content in sample gas taken under constant engine operating conditions. Experimental results obtained on a two-stroke single cylinder diesel engine confirm that the Bosch smoke density varies with the sampling position along the exhaust pipe. Data are given on a smoke content-time variation in the exhaust pipe measured directly with a light absorption smokemeter as well as a pressure variation and discussion is presented about the influence of the phase correlation among the smoke content, pressure, and flow velocity variations on the smoke density of the sample gas. The phase correlation of the smoke content variation with pulsational flow is shown to be a predominant factor affecting the amount of smoke in sample gas. It is concluded that well-mixed gas would have to be sampled for the accurate measurement.