| 摘要 |
<p>A reducing agent adding device capable of precise control for preventing freezing of a reducing agent or unfreezing the frozen reducing agent in a reducing agent pumping unit while preventing a failure due to overheating of a heating means included in the reducing agent pumping unit, and its control method. A reducing agent adding device includes a reducing agent pumping unit for supplying a reducing agent in a storage tank to a reducing agent adding unit and adds the reducing agent from the reducing agent adding unit into an exhaust passage of an internal combustion engine. The reducing agent adding device includes, in the reducing agent pumping unit, a heating means for preventing freezing of the reducing agent or unfreezing the reducing agent, a module temperature sensor used for estimating the temperature in the reducing agent pumping unit, and a heater temperature sensor used for estimating the temperature of the heating means and includes a control unit for controlling the operation of the heating means such that the temperature of the heating means does not exceed the heatproof temperature according to the sensor value of the module temperature sensor and the sensor value of the heater temperature sensor when the reducing agent is frozen.</p> |
