REDUCING AGENT SUPPLYING DEVICE

摘要

A reducing agent supplying device is for a fuel combustion system that includes a NOx purifying device (15) with a reducing catalyst arranged in an exhaust passage (10ex) to purify NOx contained in exhaust gas of an internal combustion engine (10). The reducing agent supplying device supplies a reducing agent into the exhaust passage at a position upstream of the reducing catalyst. The reducing agent supplying device includes a reforming portion (30, 50) and a reformation suppressing portion (S54, S55). The reforming portion (30, 50) reforms the reducing agent by partially oxidizing the reducing agent. When a temperature of the reducing agent is higher than a first specified temperature (T1) that is equal to or higher than an activation temperature of the reducing catalyst (about 400°C), the reformation suppressing portion (S54, S55) (i) suppresses the degree of reformation of the reducing agent in comparison with when a temperature of the reducing agent is lower than the first specified temperature (T1), or (ii) stops the reformation of the reducing agent.