| 摘要 |
PURPOSE:To enable a concentration of gas to be measured at a place where a substantial variation of temperature is found by a method wherein a heating temperature of a heater for a sensor is varied in response to a temperature of a temperature sensor arranged at a place where a gas sensor is positioned and the gas sensor is always applied to provide a specified temperature. CONSTITUTION:A temperature sensor 30 and a gas sensor 40 which can be heated by the heater 50 are positioned at a discharging part 20 of a combustion device 10. A temperature of the heater 50 is controlled by a control device 60. The control device 60 is provided with an inputting means 61 for temperature information from the temperature sensor 30, a memory means 62 for storing a predetermined temperature, a comparing means 63 for comparing the set temperature stored in the memory means 62 with a temperature inputted by the inputting means 61, and an outputting means 64 for supplying a current for keeping the gas sensor 40 at a predetermined temperature to the heater 50. The gas sensor 40 is constructed such that an outer circumferential surface of a ceramic substrate 43 has electrodes 44 and 44 fixed thereto and at the same time the outer circumferential surfaces of them are provided with a semiconductor layer 41 and a catalyst layer 42 composed of catalyst material. With this arrangement, it is possible to perform a sensing of a proper concentration of combustion gas independent of the combustion temperature. |
