Sensor element and gas sensor

Abstract

A gas sensor element, wherein an amount of flexure in a first section extending in a longitudinal direction of the sensor element from the position 8/27 of a size of the element apart from one end of the element to the other end, is set to be greater than or equal to 1/1360 and less than or equal to 1/670 with respect to the size in the longitudinal direction of the element. The amount of flexure is a sum of a distance from a regression line to an upper side maximum displacement point and a distance from the regression line to a lower side maximum displacement point when calculating the regression line representing the relation of the position X in the longitudinal direction of the element and the displacement Y in a thickness direction from a plurality of data sets showing the relation of position X and displacement Y.

1 . A long plate-like sensor element for detecting a predetermined gas component in a measurement gas, comprising:
 a gas inlet provided at an end portion in a longitudinal direction of said sensor element for talking the measurement gas from an external space into said sensor element, wherein   an amount of flexure which is a parameter for representing the extent of flexure in a thickness direction is specified by the following definition (a):   (a) in the case of calculating a regression line representing the relation of a position X in the longitudinal direction and a displacement Y in said thickness direction of said sensor element in a target section from a plurality of data sets showing the relation of said position X and said displacement Y thereby to illustrate a plurality of data points representing said plurality of data sets and said regression line on a X-Y plane, and letting a data point which distance from said regression line is maximum at an upper side and a lower side of said regression line among said plurality of data points be an upper side maximum displacement point and a lower side maximum displacement point, respectively, said amount of flexure is a sum of a distance from said regression line to said upper side maximum displacement point and a distance from said regression line to said lower side maximum displacement point, and   the amount of flexure in the first section specified in accordance with said definition (a) is greater than or equal to 1/1360 and less than or equal to 1/670 to a size in the longitudinal direction of said sensor element, said first section reaching to the other end portion of said sensor element from a position of 8/27 in a size of said sensor element from said end in the longitudinal direction of said sensor element.   
     
     
         2 . The sensor element according to  claim 1 , wherein
 said amount of flexure in said first section is greater than or equal to 5/72 and less than or equal to 5/146 to the thickness of said sensor element.   
     
     
         3 . The sensor element according to  claim 1 , wherein
 said sensor element is manufactured through a burning process, and said amount of flexure in said first section is controlled by applying pressure on a surface of said sensor element in said burning process.   
     
     
         4 . The sensor element according to  claim 3 , wherein
 pressure being applied on the surface of said sensor element is offered by placing a member with a predetermined mass on the surface of said sensor element in said burning process.   
     
     
         5 . The sensor element according to  claim 1 , wherein
 the amount of flexure in the second section specified in accordance with said definition (a) is less than or equal to 21/1340 to the size in the longitudinal direction of said sensor element, said second section reaching to the position of 8/27 in the size of said sensor element from said end in the longitudinal direction of said sensor element, and   the amount of flexure in the third section specified in accordance with said definition (a) is less than or equal to 6/1675 to the size in the longitudinal direction of said sensor element, said third section reaching to the position of 4/27 in the size of said sensor element from said other end to a direction of said end in the longitudinal direction of said sensor element.   
     
     
         6 . The sensor element according to  claim 5 , wherein
 said sensor element is manufactured through a burning process, and said amount of flexure in said second section and said amount of flexure in said third section are controlled by applying pressure on a surface of said sensor element in said burning process.   
     
     
         7 . The sensor element according to  claim 6 , wherein
 pressure being applied on the surface of said sensor element is offered by placing a member with a predetermined mass on the surface of said sensor element in said burning process.   
     
     
         8 . The sensor element according to  claim 1 , wherein
 said predetermined gas component is a nitrogen oxide gas, and consisted of zirconia as a main component.   
     
     
         9 . A gas sensor comprising:
 a long plate-like sensor element for detecting a predetermined gas component in a measurement gas, including:   a gas inlet provided at an end in a longitudinal direction of said sensor element for talking the measurement gas from an external space into said sensor element, wherein   an amount of flexure which is a parameter for representing the extent of flexure in a thickness direction is specified by the following definition (a):   (a) in the case of calculating a regression line representing the relation of a position X in the longitudinal direction and a displacement Y in said thickness direction of said sensor element in a target section from a plurality of data sets showing the relation of said position X and said displacement Y thereby to illustrate a plurality of data points representing said plurality of data sets and said regression line on a X-Y plane, and letting a data point which distance from said regression line is maximum at an upper side and a lower side of said regression line among said plurality of data points be an upper side maximum displacement point and a lower side maximum displacement point, respectively, said amount of flexure is a sum of a distance from said regression line to said upper side maximum displacement point and a distance from said regression line to said lower side maximum displacement point, and   the amount of flexure in the first section specified in accordance with said definition (a) is greater than or equal to 1/1360 and less than or equal to 1/670 to a size in the longitudinal direction of said sensor element, said first section reaching to the other end portion of said sensor element from a position of 8/27 in a size of said sensor element from said end portion in the longitudinal direction of said sensor element.   
     
     
         10 . The gas sensor according to  claim 9 , wherein
 said amount of flexure in said first section is greater than or equal to 5/72 and less than or equal to 5/146 to the thickness of said gas sensor.   
     
     
         11 . The gas sensor according to  claim 9 , wherein
 said gas sensor is manufactured through a burning process, and said amount of flexure in said first section is controlled by applying pressure on a surface of said gas sensor in said burning process.   
     
     
         12 . The gas sensor according to  claim 11 , wherein
 pressure being applied on the surface of said gas sensor is offered by placing a member with a predetermined mass on the surface of said gas sensor in said burning process.   
     
     
         13 . The gas sensor according to  claim 9 , wherein
 the amount of flexure in the second section specified in accordance with said definition (a) is less than or equal to 21/1340 to the size in the longitudinal direction of said sensor element, said second section reaching to the position of 8/27 in the size of said sensor element from said end in the longitudinal direction of said sensor element, and   the amount of flexure in the third section specified in accordance with said definition (a) is less than or equal to 6/1675 to the size in the longitudinal direction of said sensor element, said third section reaching to the position of 4/27 in the size of said sensor element from said other end portion to a direction of said end portion in the longitudinal direction of said sensor element.   
     
     
         14 . The gas sensor according to  claim 13 , wherein
 said gas sensor is manufactured through a burning process, and said amount of flexure in said second section and said amount of flexure in said third section are controlled by applying pressure on a surface of said sensor element in said burning process.   
     
     
         15 . The gas sensor according to  claim 14 , wherein
 pressure being applied on the surface of said gas sensor is offered by placing a member with a predetermined mass on the surface of said sensor element in said burning process.   
     
     
         16 . The gas sensor according to  claim 9 , wherein
 said predetermined gas component is a nitrogen oxide gas, and consisted of zirconia as a main component.