On the Uniformity of Combustion Gas Composition in the Exhaust Stroke in Diesel Engines

Abstract

The measuring accuracy of scavenging efficiency by the gas sampling method depends upon mainly whether the sample represents the average composition of combustion gas or not. However, its evaluation has not been made sufficiently yet. In this paper, discussion is given about the experimental relation between the composition variation and the mass fraction of combustion gas discharged in the exhaust stroke, to evaluate the uniformity of combustion gas composition, and the following results are obtained. The measuring accuracies of the scavenging efficiency by the exhaust sampling method and the combustion chamber sampling method are estimated within errors of 1% and 2% respectively, for a sample during the last period of expansion stroke under a full operating load.