Abstract
Particulate emission from diesel engines is one of the biggest environmental issues, especially in terms of the influence on human's health. At present, the gravimetric method, which is specified in the relevant regulations, is commonly used to measure particulate mass emitted from engines. Although the gravimetric method is the standard in particulate mass measurement, this method has some disadvantages. For example, by the gravimetric method, it is difficult to know when and how the engine emits the particulate matter, such as soot and soluble organic fraction (SOF), during emission tests. Additionally, this method consumes a lot of time in getting the particulate mass, and is not suitable for the measurement of low-level emissions from clean engines. In this paper, a new PM analyzing system which can measure soot and SOF in low mass level continuously has been developed. It consists of a diffusion charging (DC) detector with a dilution device for soot measurement, and two flame ionization detectors (FID) for SOF measurement. This paper describes the principles of these analyzing techniques which allow soot and SOF to be measured continuously. It is confirmed that there are good correlations in the concentration of the PM constitutes (soot and SOF) between the new system and the conventional gravimetric method with soxhlet extraction method. The correlation factor (R2) obtained for soot in the study is 0.9820 and that for SOF is 0.9507. The total PM mass concentration from the new analyzer shows a good correlation with the gravimetric method as well. Measurement results of the new analyzer in real-time test are also described in the paper.
