Patent ID: 7895829

Claim:
An exhaust purification device of an engine comprising: a reducing agent vessel that stores a liquid reducing agent; a reducing agent addition valve that receives the reducing agent from the reducing agent vessel and that adds the reducing agent into an exhaust passage of the engine; an exhaust purification catalyst that is provided in the exhaust passage downstream of the reducing agent addition valve and that promotes specific exhaust purification reaction with the added reducing agent; a passage collecting pipe that consists of a plurality of gathered passages, the gathered passages providing a reducing agent passage, through which the reducing agent is supplied from the reducing agent vessel to the reducing agent addition valve, and at least one medium circulation passage for circulating a thawing medium for thawing the reducing agent; a temperature sensing device that senses temperature of the reducing agent in the reducing agent passage; and a circulation stopping device that stops the circulation of the thawing medium through the medium circulation passage when the sensed temperature of the reducing agent rises to a predetermined temperature range set based on a reducing agent reaction temperature, above which a chemical reaction of the reducing agent occurs to generate a gas.