A sensor element for detecting a parameter of a gas mixture in a gas chamber, having a first electrode and a first diffusion barrier layer arranged to be coupled to said first electrode in a predetermined first region, and arranged such that the gas mixture of the gas chamber only impinges on the first electrode in the first region via the first diffusion barrier layer. In addition, the sensor element has a second electrode arranged such that the gas mixture of the gas chamber impinges on the second electrode in a further first region. The sensor element includes a solid electrolyte designed to be coupled to the first and the second electrodes.

A sensor element for detecting a parameter of a gas mixture in a gas chamber, having a first electrode and a first diffusion barrier layer arranged to be coupled to said first electrode in a predetermined first region, and arranged such that the gas mixture of the gas chamber only impinges on the first electrode in the first region via the first diffusion barrier layer. In addition, the sensor element has a second electrode arranged such that the gas mixture of the gas chamber impinges on the second electrode in a further first region. The sensor element includes a solid electrolyte designed to be coupled to the first and the second electrodes.

The sensor control unit is used for a gas sensor disposed in an exhaust pipe in an engine as an internal combustion engine of a vehicle. The gas sensor includes a sensor cell having an exhaust gas electrode, an atmosphere side electrode and a solid electrolyte, and a heater that heats the sensor cell. The sensor control unit includes a heater control unit that controls a heater to heat a sensor cell. The heater control unit heats the sensor cell to be at an operation control temperature during the combustion operation of the engine and heats the sensor cell to be at an operation stop control temperature which is higher than the operation control temperature.

The sensor control unit is used for a gas sensor disposed in an exhaust pipe in an engine as an internal combustion engine of a vehicle. The gas sensor includes a sensor cell having an exhaust gas electrode, an atmosphere side electrode and a solid electrolyte, and a heater that heats the sensor cell. The sensor control unit includes a heater control unit that controls a heater to heat a sensor cell. The heater control unit heats the sensor cell to be at an operation control temperature during the combustion operation of the engine and heats the sensor cell to be at an operation stop control temperature which is higher than the operation control temperature.

A sensor element 101 of a gas sensor 100 includes a blocking portion 65 including an outer blocking layer 67 that is formed to cover, in an upper surface of a multilayer body, at least a part of an upper closest region 6a where an outer pump electrode 23 is not disposed and a distance up to a third inner cavity 61 is minimal. The outer blocking layer 67 does not have conductivity for one or more among various types of substances containing oxygen. The outer blocking layer 67 is disposed between a lead line 93 for the outer pump electrode and the upper surface of the multilayer body to provide insulation therebetween, and is disposed between an upper connector pad 91 and the upper surface of the multilayer body to provide insulation therebetween. A porous protective layer 24 covers the outer pump electrode 23.

A sensor element 101 of a gas sensor 100 includes a blocking portion 65 including an outer blocking layer 67 that is formed to cover, in an upper surface of a multilayer body, at least a part of an upper closest region 6a where an outer pump electrode 23 is not disposed and a distance up to a third inner cavity 61 is minimal. The outer blocking layer 67 does not have conductivity for one or more among various types of substances containing oxygen. The outer blocking layer 67 is disposed between a lead line 93 for the outer pump electrode and the upper surface of the multilayer body to provide insulation therebetween, and is disposed between an upper connector pad 91 and the upper surface of the multilayer body to provide insulation therebetween. A porous protective layer 24 covers the outer pump electrode 23.

A nitrogen oxide based gas sensor includes: a substrate provided with a beam structure having a MEMS structure; a heater disposed on the substrate; a lower electrode disposed on the heater, a solid electrolyte layer disposed on the lower electrode; an upper electrode disposed on a surface of the solid electrolyte layer facing the lower electrode and configured to introduce a measurement target gas; a cavity portion formed in the substrate; and a gas flow path disposed so as to connect the cavity portion and the lower electrode, wherein the gas sensor is configured to detect a concentration of nitrogen oxide in the measurement target gas.

A nitrogen oxide based gas sensor includes: a substrate provided with a beam structure having a MEMS structure; a heater disposed on the substrate; a lower electrode disposed on the heater, a solid electrolyte layer disposed on the lower electrode; an upper electrode disposed on a surface of the solid electrolyte layer facing the lower electrode and configured to introduce a measurement target gas; a cavity portion formed in the substrate; and a gas flow path disposed so as to connect the cavity portion and the lower electrode, wherein the gas sensor is configured to detect a concentration of nitrogen oxide in the measurement target gas.

An apparatus and method for individually detecting NO and NO.sub.2 concentrations as NO.sub.X components of an object gas. An NO concentration corresponding value is obtained from a first detection element not having a reduction section. An NO concentration corresponding value is obtained from a second detection element having a reduction section, and having an NO.sub.2/NO sensitivity ratio greater than that of the first detection element. The difference ΔC between the NO concentration corresponding values of the two detection elements is obtained, and divided by the difference ΔS between the NO.sub.2/NO sensitivity ratios of the two detection elements, whereby an NO.sub.2 concentration corresponding value is obtained. A value obtained by multiplying the NO.sub.2 concentration corresponding value by the NO.sub.2/NO sensitivity ratio of the second detection element is subtracted from the NO concentration corresponding value of the second detection element, whereby an NO concentration corresponding value is obtained.

An apparatus and method for individually detecting NO and NO.sub.2 concentrations as NO.sub.X components of an object gas. An NO concentration corresponding value is obtained from a first detection element not having a reduction section. An NO concentration corresponding value is obtained from a second detection element having a reduction section, and having an NO.sub.2/NO sensitivity ratio greater than that of the first detection element. The difference ΔC between the NO concentration corresponding values of the two detection elements is obtained, and divided by the difference ΔS between the NO.sub.2/NO sensitivity ratios of the two detection elements, whereby an NO.sub.2 concentration corresponding value is obtained. A value obtained by multiplying the NO.sub.2 concentration corresponding value by the NO.sub.2/NO sensitivity ratio of the second detection element is subtracted from the NO concentration corresponding value of the second detection element, whereby an NO concentration corresponding value is obtained.