Portable electrometric apparatus for roadside analysis of automotive exhaust emission

摘要

A method and apparatus for instantaneously measuring the level of carbon dioxide (and other gases) in automotive combustion exhaust analysis is provided in the form of a portable battery driven roadside diagnostic instrument in which the CO.sub.2 level is measured by a calorimetric technique utilizing light as the energy source and a piezoelectric bimorph to vibrate a single fiber-optic element to multiplex between two fiber-optic receptors delivering the light to a measurement cell and a reference cell. The measurement cell comprises a salt of an acid-base indicator dye which provides proportional color change on contact with CO.sub.2. The dye is supported on a polymetric film in the cell.