Abnormality diagnosis device for pm sensor

Abstract

A PM sensor is arranged downstream of a one-side blocked filter that collects a particulate matter in exhaust gas of an engine, and first and second sensor abnormality diagnoses are executed based on output of the PM sensor. In the first sensor abnormality diagnosis, a filter-outflow PM amount (an amount of the PM flowing out from the one-side blocked filter) is estimated based on a working condition of the engine and a PM collection rate of the one-side blocked filter, and an occurrence of output abnormality of the PM sensor is determined by comparing a sensor-detection PM amount (an amount of the PM detected based on the output of the PM sensor) with the filter-outflow PM amount. In the second sensor abnormality diagnosis, an engine discharging PM amount (an amount of the PM discharged from the engine) is estimated based on a working condition of the engine, and an occurrence of output abnormality of the PM sensor is determined by comparing an increasing rate of the output of the PM sensor with an increasing rate of the engine discharging PM amount.

Dependencies are inferred from the claim text.