| 摘要 |
PURPOSE: A method of checking a trouble of a rear oxygen sensor in a vehicle is provided to prevent a trouble checked as normality when the maximum amplitude of an output voltage characteristic is under a set voltage signal value. CONSTITUTION: A method of checking a trouble of a rear oxygen sensor in a vehicle includes steps of receiving a monitoring signal from corresponding sensors to check whether a monitoring condition of an oxygen sensor is satisfied or not(S10); checking whether a monitoring start condition of the oxygen sensor is satisfied or not through analysis of the monitoring signal(S20); checking whether a vehicle speed signal detected from a vehicle speed sensor is zero or not(S30); abstracting a maximum value(Vmax) and a minimum value(Vmin) from the output value of the rear oxygen sensor(S40); and checking whether a variation of the output maximum value and the output minimum value of the rear oxygen sensor is under 0.078V or not and checking the rear oxygen sensor in a fault caused by the sticking of the rear oxygen sensor(S50). The method of checking a trouble of the rear oxygen sensor further includes steps of checking the oxygen sensor into abnormal state, if the variation of the output maximum value and the output minimum value of the rear oxygen sensor is over 0.078V and the minimum amplitude of an output voltage characteristic of the rear oxygen sensor doesn't satisfy the checking condition(S60); maintaining a fuel rich control state to a desired fuel consumption ratio for a predetermined time(S70); detecting the output value(Vfront) of a front oxygen sensor and the output value of the rear oxygen sensor for the predetermined time(S80); and determining the rear oxygen sensor into a fault state caused by stuck fault and into a normal state according to the output value of the front oxygen sensor and the output value of the rear oxygen sensor(S90).
|
