| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust gas purifying system for internal combustion engines which has a constitution for detecting a failure of a PM sensor arranged downstream of a DPF without restriction to and influence on a collection rate of the DPF during failure detection.SOLUTION: Normal time, when a failure diagnosis of a PM sensor 5 attached to a downstream hole part 31 downstream of a DPF 4 is performed, the PM sensor 5 is moved to a first upstream hole part 30 upstream of the DPF 4, and an exhaust gas is discharged from an engine 2. An ECU 6 stores a program for the failure diagnosis of the PM sensor and diagnoses a failure of the PM sensor 5 by comparing an output of the PM sensor 5 to a normal output through the execution of the program. Normal time, the hole part 30 may be closed by a lid member, for instance. |
