EXHAUST CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

摘要

An exhaust control system for an internal combustion engine comprises: a trapping capability acquisition part that obtains information regarding a PM trapping capability, based on a detection value of an exhaust sensor provided to detect a predetermined parameter relating to an exhaust gas flowing out of an SCRF; and a NOx reduction capability acquisition part obtains information regarding a NOx reduction capability, based on an amount of NOx in the exhaust gas flowing out of the SCRF. The exhaust control system determines and distinguishes between a trapping abnormal state in which a PM trapping function by the SCRF is failed and a sensor abnormal state in which a detection function of the predetermined parameter by the exhaust sensor is failed, based on the NOx reduction capability obtained by the NOx reduction capability acquisition part, when the trapping capability obtained by the trapping capability acquisition part is in a predetermined low trapping capability state. This allows for accurate abnormality determination with regard to the SCRF in the exhaust control system for the internal combustion engine having the SCRF.

主权项

1. An exhaust control system for an internal combustion engine, comprising:
a NOx reduction filter that is provided in an exhaust passage of the internal combustion engine to trap a particulate matter included in an exhaust gas and is configured by supporting a selective catalytic reduction NOx catalyst that selectively reduces NOx in the exhaust gas using ammonia as a reducing agent; a reducing agent supplier that supplies ammonia or a precursor of ammonia to the NOx reduction filter via the exhaust gas flowing into the NOx reduction filter; and a controller, comprising at least one processor, configured to: obtain information regarding a trapping capability of the NOx reduction filter to trap the particulate matter in the exhaust gas, based on a detection value of an exhaust sensor provided to detect a predetermined parameter relating to the exhaust gas flowing out of the NOx reduction filter; obtain information regarding a NOx reduction capability of the NOx reduction filter, based on an amount of NOx in the exhaust gas flowing out of the NOx reduction filter; and determine and distinguish between a trapping abnormal state in which a trapping function of the particulate matter by the NOx reduction filter is failed and a sensor abnormal state in which a detection function of the predetermined parameter by the exhaust sensor is failed, based on the obtained information regarding the NOx reduction capability, when the obtained information regarding the trapping capability indicates that the trapping capability is in a predetermined low trapping capability state.