Method for diagnosing operability of exhaust gas sensor, involves comparing integral of heating power/temperature characteristic value with preset limit if integral of exhaust gas flow characteristic value is more than preset limit

摘要

An exhaust gas flow characteristic value in exhaust passage and heating power or temperature characteristic value of heating element (26) are determined. The temporal gradients of characteristic values are determined and integrated. The integral of heating power or temperature characteristic value is compared with predetermined limit when integral of exhaust gas flow characteristic value is greater than predetermined limit. The operability of exhaust gas sensor is evaluated based on comparison result. An independent claim is included for device for diagnosing operability of exhaust gas sensor.