Patent ID: 8431002
Filing Date: 2013-04-30
Classification: G01N

Abstract:
1. A gas sensor comprising a gas sensor element, the gas sensor element comprising: a first detection chamber into which a gas to be detected is introduced through a first diffusion resisting portion; a first oxygen pumping cell including a first solid electrolyte body and a pair of first electrodes formed on the first solid electrolyte body, wherein the pair of first electrodes include a first inner electrode disposed within the first detection chamber, wherein the first oxygen pumping cell is configured to pump oxygen from/into the gas which has been introduced into the first detection chamber; a second detection chamber into which the gas given the oxygen pumping in the first detection chamber is introduced through a second diffusion resisting portion; a second oxygen pumping cell including a second solid electrolyte body and a pair of second electrodes formed on the second solid electrolyte body, wherein the pair of second electrodes include an inside second pumping electrode disposed within the second detection chamber, wherein the second oxygen pumping cell is configured to pass an electric current according to a concentration of specific gas component within the second detection chamber; and an oxygen-concentration sensing cell including a third solid electrolyte body and a pair of third electrodes disposed on the third solid electrolyte body, wherein the pair of third electrodes include a sensing electrode disposed within the first detection chamber, wherein the oxygen-concentration sensing cell is configured to generate a voltage between the third electrodes in accordance with an oxygen concentration within the first detection chamber; wherein the sensing electrode is disposed downstream beyond the first inner electrode relative to a flow direction of the gas, wherein a cross-sectional area of a space of the first detection chamber through which the gas flows falls within a range from 0.03 mm wherein a center of the sensing electrode is located downstream beyond a downstream end of the first inner electrode to cause a distance between the center of the sensing electrode and the downstream end of the first inner electrode to be greater than or equal to ten times magnitude of a height of the space, the height being a length taken in a laminating direction of the first solid electrolyte body, wherein a thickness of the first inner electrode in the laminating direction is smaller than the height of the space facing the first inner electrode.