| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a gas sensor in which the extension of light-off time and the power consumption of a heater are suppressed, cracking in a laminate formed of a gas sensor element body and the heater and the peeling of a porous protective layer formed on the laminate are suppressed, and having excellent reliability. <P>SOLUTION: This gas sensor includes a gas sensor element 20 and a generally cylindrical main metal fitting 10 so holding the gas sensor element 20 that the end 20a of the gas sensor element projects from the end 11 thereof. The gas sensor element 20 of the gas sensor 1 includes the laminate 21 formed of the gas sensor element body 100 and the heater 200 and the porous protective layer 22 covering the end 20a thereof. Where the maximum thickness of the porous protective layer 22 formed at the end 20a of the gas sensor element 20 is T<SB>MAX</SB>, and the minimum thickness thereof is T<SB>MIN</SB>, T<SB>MAX</SB>≤700 μm, T<SB>MIN</SB>≥100 μm, and (T<SB>MAX</SB>-T<SB>MIN</SB>)/T<SB>MAX</SB>≤0.6. <P>COPYRIGHT: (C)2008,JPO&INPIT |
