Patent ID: 6313464
Filing Date: 2001-11-06
Classification: G01N

Abstract:
A method of detecting the concentration of a plurality of gases in the exhaust gases produced by the operation of a gasoline powered engine including the steps ofarranging infrared light transmitting pipes for transmitting an infrared light beam over a preselected path and to exit said pipes upon transversing said path,providing an infrared light beam and projecting the beam to be transmitted over a preselected distance defined by said light transmitting pipes,mounting a first-infrared detector-filter having a narrow band infrared filter for receiving the infrared beam exiting said pipes and transmitting a preselected narrow band of the infrared beam including one of the gases to be detected to the detector and reflecting the remaining portion of the infrared beam,the step of mounting said detector-filter including mounting the detector-filter at a preselected acute angle to the path of the infrared beam exiting said pipes and receiving said exiting beam,mounting a second infrared detector-filter having a narrow band infrared filter for receiving the portion of the infrared beam reflected from said first detector-filter and transmitting a preselected narrow beam of said reflected portion of the infrared beam including a second gas to be detected to said second detector-filter and reflecting the remaining portion of said reflected portion of the infrared beam.