| 摘要 |
<p>An exhaust purifying device for an internal combustion engine, wherein the exhaust purifying device uses a relatively simple and inexpensive structure to prevent heat damage to a reducing agent discharge valve and also prevent crystallization of a reducing agent occurring in or around a nozzle of the reducing agent discharge valve, can dissolve generated crystals of the reducing agent, and can defrost frozen reducing agent. A method of controlling the exhaust purifying device is also provided. An exhaust purifying device adapted for use with an internal combustion engine and provided in an exhaust path of the engine, wherein the exhaust purifying device is provided with a switching means provided on the exhaust upstream of a reducing agent discharge valve and changing the direction of flow of exhaust gas, an abnormality determining section for determining at least one of whether or not the reducing agent discharge valve is in a state in which the reducing agent discharge valve can incur heat damage, whether or not the reducing agent is in a state in which the reducing agent can crystallize in or around a nozzle of the reducing agent discharge valve, and whether or not the reducing agent has crystallized or frozen in or around the nozzle, and a switching means control section for controlling the switching means based on the result of determination by the abnormality determining section.</p> |
