| 摘要 |
PURPOSE:To maintain the heater of an oxygen concn. sensor at an optimum temp. by setting basic electric power corresponding to the operating condition of an internal combustion engine, correcting the basic electric power according to ambient temp., setting the target electric power and controlling the heater of said sensor by the target power. CONSTITUTION:The basic electric energy of the heater IV of an oxygen concn. sensor IIIis determined from the calculation equation in which the engine speed and the pressure of an intake pipe detected by a means VI for detecting the operating condition are used as a parameter. The intake air temp. is measured by a temp. sensor V and the process for determining the corrected electric energy for the basic electric energy is executed according to said temp. The target electric energy to be supplied to the heater IV is calculated from the basic electric energy and corrected electric energy. When the target electric energy is determined, a duty ratio to be conducted to the heater IV is calculated and the pulse signal of the duty ratio is supplied to the heater VIIby a controlling means IX. If the heater is constituted in the above-mentioned way, the heating of the oxygen concn. sensor to the prescribed temp. or above at all times is made possible and the heater is kept at the temp. at which disconnection and the breakdown of the detecting element do not arise. |
