Patent ID: 7901556

Claim:
A gas sensor having a length with a base end and a top end opposite the base end comprising: a gas sensor element having a sensing portion sensitive to a concentration of a gas to be measured to provide a signal indicative thereof; a housing having a base end and a top end opposite the base end, said housing having said gas sensor element retained therein; a cover assembly having a base end and a top end which is opposite the base end and close to the top end of the gas sensor, said cover assembly including an outer cover and an inner cover disposed inside the outer cover, said cover assembly being joined at the base end thereof to the top end of said housing to place the sensing portion of said gas sensor element within the inner cover; an outer gas inlet formed in a peripheral wall of the outer cover of said cover assembly; an outer gas outlet formed in a portion of the outer cover of said cover assembly which is located closer to the top end of said cover assembly than said outer gas inlet; and an inner gas inlet formed in a portion of the inner cover of said cover assembly which is located closer to the top end of said cover assembly than said outer gas inlet, said inner gas inlet being formed by an opening which is so shaped as to have an axial center line that is oriented from outside to inside the inner cover and defined to have a vertical quadrature component oriented in a rectangular coordinate system toward the base end of the gas sensor in an axial direction of the gas sensor, wherein the axial center line of the opening is defined to have said vertical quadrature component and a transverse quadrature component which is oriented toward and perpendicular to a longitudinal axis of the gas sensor that extends in the axial direction of the gas sensor, the transverse quadrature component being perpendicular to the vertical quadrature component, and wherein an angle which the axial center line of the inner gas inlet opening makes with the transverse quadrature component is 30° or more, wherein said gas sensor element has affixed to a surface thereof a measurement gas electrode which is to be exposed to the gas to be measured, the measurement gas electrode having a length with a base end and a top end which is opposite the base end thereof and faces the top end of said cover assembly, and wherein the inner gas inlet is located within half the length of the measurement gas electrode from the base end of the measurement gas electrode.