Study On Pocketable Opacity Smokemeter

Exhaust emission of vehicle engines is one of the primary air pollution sources. In order to protect the human survival environment, many countries established increasing strict statutes and restrictive standards to limit emission of engines. Assorting with the actualization of statutes and standards, all kinds of testing instruments are applied to test and control deleterious emissions from engines strictly. This paper analyzed the form of deleterious emissions and their harms. Then the paper did deep research in the inborn mechanism and affected factors of the smoke from engines. Based on the principle of full flow extinction, this paper excogitated a pocketable opacity smokemeter. This instrument transformed the smoke density to an electronic signal through photoelectric sensors. The signal was transacted in amplifier and shaping circuits, then the worked signal was transformed to a digital signal through A/D transform circuit. The smoke density value calculated from the digital signal was displayed in real time by the single chip. Steady excursion experiment and engine verified experiment were done in order to test the performance of this instrument. The experiments showed that this pocketable opacity smokemeter could test the smoke density properly. But the stability of this instrument should be improved to fulfill the requirement of the precision.