公开(公告)号：US06841778B1

公开(公告)日：2005-01-11

申请号：US10099609

申请日：2002-03-15

申请人： Peter S. Shifflett ,  James H. Johnson ,  Jason K. Webster ,  Dennis L. Smith

发明人： Peter S. Shifflett ,  James H. Johnson ,  Jason K. Webster ,  Dennis L. Smith

IPC分类号： G01N21/33 ,  G01N21/35 ,  G01N21/00

CPC分类号： G01N21/33 ,  G01N21/3504 ,  G01N21/359 ,  G01N21/532 ,  G01N2021/1795 ,  G01N2021/3513

摘要： A method and apparatus for measuring particulates in vehicle emissions. An ultraviolet light beam having a predetermined wavelength, and an infrared light beam having a predetermined wavelength are propagated through the exhaust plume of a vehicle that has passed on the road. The reduction in intensities of the light beams are measured. The reduction in intensity of the ultraviolet light is due to scattering of the light by particles in the exhaust. A portion of the reduction in intensity of the infrared light is due to absorption of the light by carbon dioxide in the exhaust and a portion of the reduction in intensity is due to the scattering of light by the particles in the exhaust. To distinguish between the two, a portion of the infrared light is run through a test cell with a known amount of carbon dioxide. The reduction in intensity is measured and compared with the reduction in intensity of the infrared light passing through the exhaust plume. As one measure of particulate content, the ratio of the particles in the exhaust whose diameter is greater than said predetermined wavelength of ultraviolet light to the density of the carbon dioxide in the exhaust plume is calculated. Another measure of particulate content is the ratio of the particles in the exhaust whose diameter is greater than said predetermined wavelength of infrared light to the density of the carbon dioxide in the exhaust plume. The average size of the particles is calculated from the ratio of the particles whose diameter is greater than the predetermined wavelength of ultraviolet light to the particles whose diameter is greater that the predetermined wavelength of infrared light is calculated. The average particle size is determined from the Mie efficiency using Mie scattering and absorption theory.

摘要翻译： 一种用于测量车辆排放物中的微粒的方法和装置。 具有预定波长的紫外光束和具有预定波长的红外光束通过已经通过道路的车辆的排气羽流传播。 测量光束强度的降低。 紫外线强度的降低是由于排出物中的颗粒散射的光。 红外光强度降低的一部分是由于排气中的二氧化碳吸收光，部分还原强度是由于排气中的颗粒的散射引起的。 为了区分两者，一部分红外光穿过具有已知量的二氧化碳的测试电池。 测量强度的降低并与通过排气羽流的红外光的强度的降低进行比较。 作为颗粒含量的一个量度，计算直径大于紫外光的预定波长的排气中的颗粒与排气羽流中二氧化碳密度的比例。 颗粒含量的另一个测量是直径大于所述预定波长的红外光的排气中的颗粒与排气羽流中的二氧化碳的密度之比。 颗粒的平均尺寸由直径大于紫外光的预定波长的颗粒与直径大于计算红外光的预定波长的颗粒的比率计算。 平均粒径由米氏散射和吸收理论的米氏效率确定。