Exhaust purification system and method for controlling exhaust purification system

摘要

Provided is an exhaust purification system capable of clearing a blockage of a reducing agent injection valve caused by solidification of an aqueous urea solution soon after starting an engine and preventing degradation in exhaust purification efficiency when starting an internal combustion engine. An exhaust purification system with a DPF, a reducing agent injection valve, and an SCR catalyst in order from the exhaust upstream side includes: an operation state detecting unit capable of detecting starting and stopping of the internal combustion engine; a forced regeneration control unit which performs forced regeneration of the DPF; a condition establishment determining unit which determines whether there is a possibility of solidification of the aqueous urea solution when the operation state detecting unit detects that the internal combustion engine is stopped; a data storage unit which stores the determination result of the condition establishment determining unit as data; and a blockage-clearing control unit which controls a temperature raising unit for raising the temperature of the reducing agent injection valve so as to raise the temperature of the reducing agent injection valve based on the data when starting the internal combustion engine.

主权项

1. An exhaust purification system with a DPF which collects exhaust particulates in an exhaust gas, a reducing agent injection valve which injects an aqueous urea solution as a reducing agent into the exhaust gas, and an SCR catalyst which purifies a NOx in the exhaust gas by using the aqueous urea solution, the DPF, the reducing agent injection valve and the SCR catalyst being provided in sequence from the exhaust upstream side, the exhaust purification system comprising:
an operation state detecting unit configured to detect starting and stopping of an internal combustion engine; a condition establishment determining unit which determines whether there is a possibility of solidification of the aqueous urea solution when the operation state detecting unit detects the stopping of the internal combustion engine; a data storage unit which stores a determination result of the condition establishment determining unit as data; and a blockage-clearing control unit which activates a forced regeneration unit of the DPF for raising a temperature of the reducing agent injection valve based on the determination result from the data storage unit when starting the internal combustion engine so as to raise the temperature of the reducing agent injection valve.