The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jan. 29, 1991

Filed:

May. 15, 1990
Applicant:
Inventors:

Yasunori Iwakiri, Yokohama, JP;

Akinobu Moriyama, Yokohama, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
204406 ; 123489 ; 20415314 ; 204410 ;
Abstract

An NOx concentration measuring apparatus employing first and second wide-range air/fuel ratio sensors for measuring an NOx concentration of gases introduced thereto through a first passage. First and second restricted orifices are provided in the first passage upstream of the first and second sensors. A second passage is connected to the first passage between the first and second orifices. A suction pump is connected to the first passage downstream of the first and second sensors for producing a suction vacuum in the first passage and is also connected to the second passage for producing a suction vacuum in the second passage. The first and second orifices are effective to prevent momentary gas pressure fluctuations from affecting the accuracy of measurement of the first and second sensors.


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