| 主权项 |
1. A gas sensor that has a sensor element formed of an oxygen-ion conductive solid electrolyte and identifies concentrations of a water vapor component and a carbon dioxide component of a measurement gas based on a current flowing through said solid electrolyte, said sensor element comprising:
a first diffusion control part that is in communication with the outside and applies a first diffusion resistance to said measurement gas; a first internal space that is in communication with said first diffusion control part, into which said measurement gas is introduced with said first diffusion resistance from said outside; a second diffusion control part that is in communication with said first internal space and applies a second diffusion resistance to said measurement gas; a second internal space that is in communication with said second diffusion control part, into which the measurement gas is introduced with said second diffusion resistance from said first internal space; a main electrochemical pumping cell formed of a main internal electrode formed to face said first internal space, a first external electrode formed on an outer surface of said sensor element, and said solid electrolyte located between said main internal electrode and said first external electrode, said main electrochemical pumping cell adjusting an oxygen partial pressure of said first internal space such that substantially all of said water vapor component and said carbon dioxide component are decomposed in said first internal space; a first measuring electrochemical pumping cell formed of a first measuring internal electrode formed to face said second internal space, a second external electrode formed on the outer surface of said sensor element, and said solid electrolyte located between said first measuring internal electrode and said second external electrode, said first measuring electrochemical pumping cell adjusting an oxygen partial pressure of said second internal space such that hydrogen generated through the decomposition of said water vapor component is selectively burned in said second internal space; a second measuring electrochemical pumping cell formed of a second measuring internal electrode formed at a position opposite to said second diffusion control part with respect to said first measuring internal electrode in a space being in communication with an inside of said second internal space or said second internal space, a third external electrode formed on the outer surface of said sensor element, and said solid electrolyte located between said second measuring internal electrode and said third external electrode, said second measuring electrochemical pumping cell adjusting an oxygen partial pressure near a surface of said second measuring inside pump electrode such that carbon monoxide generated through the decomposition of said carbon dioxide component is selectively burned near the surface of said second measuring inside pump electrode; a reference gas space into which a reference gas is introduced; and a reference electrode formed to face said reference gas space, wherein said gas sensor identifies
the concentration of said water vapor component existing in said measurement gas based on the magnitude of a current flowing between said first measuring internal electrode and said second external electrode when said first measuring electrochemical pumping cell supplies oxygen to said second internal space, andthe concentration of said carbon dioxide component existing in said measurement gas based on the magnitude of a current flowing between said second measuring internal electrode and said third external electrode when said second measuring electrochemical pumping cell supplies oxygen to a surface of said second measuring internal electrode. |
