| 摘要 |
PURPOSE: To provide a method for easily determining whether formation of a mixture is not adequate or a defect is caused in a heated lambda sonde. CONSTITUTION: A sonde voltage is continuously measured so as to be compared with a lower diagnosis-limit value and an upper diagnosis-limit value. When the value lowers or exceeds the diagnosis-limit value, a lambda regulation value of a lambda regulator is changed in the enriching/leaning direction to a lambda regulation limit value, and heating output in a sonde heating unit is increased/reduced after the lapse of a predetermined time in which the lambda regulation value stays within the lambda regulation limit value. If a diagnosis- limit value to a continuous leaning condition is exceeded again or the diagnosis- limit value is lowered again, a mixture formation uncompleted condition, a continuous leaning condition, or a continuous enriching condition is determined, while a fault or a defect in the sonde is determined in other cases. |
