| 摘要 |
PURPOSE:To execute a suitable temperature control of an oxygen sensor and to enable execution of highly precise measurement by providing measuring means of an impression voltage and a current of a heater part, a power control device and an arithmetic means and by determining an ordinary temperature resistance value of a heater by computation. CONSTITUTION:A temperature control device 2 controlling the temperature of a heater part 1 of an oxygen sensor includes a heater current measuring part 11 and a voltage measuring part 12. In order to determine an ordinary temperature resistance value of a heater, an impression voltage VH1 is impressed on the heater for one minute, a heater current IH1 is measured and a heater resistance RH1=VH1/IH1 is calculated. Next, an impression voltage VH2 is impressed on the heater for two minutes, a heater current IH2 is measured then, a heater resistance RH2=VH2/IH2 is calculated and a heater supply power PW2=VH2*IH2 is calculated. Lastly, a ordinary temperature heater resistance RH0=K1*RH1/RH2+K2*PW2+B is calculated from PH1, RH2 and PW2 obtained. In this equation, K1, K2 and B denote constants determined by a regression computation process by an experiment beforehand according to the shape of the oxygen sensor. |
