Patent ID: 6112575
Filing Date: 2000-09-05
Classification: G01M

Abstract:
An emissions gas analyzer for analyzing an exhaust flow of an engine, said analyzer comprising:a gas control valve having a first gas input, a second gas input and a gas output;means for diverting a portion of the exhaust flow to said first gas input of said gas control valve;means for providing a fresh air stream to said second gas input of said gas control valve;a constant volume pump operatively coupled to said gas output of said gas control valve;a multi-gas analyzer operatively coupled to said gas output of said gas control valve and to said constant volume pump; andmodulating means for pulse width modulating said gas control valve between a first position and a second position, said first position permitting gas from said first gas input to flow out of said gas output of said control valve and said second position permitting gas from said second gas input to flow out of said gas output of said control valve.