Reducing agent i.e. aqueous urea solution, supply system, has control device for controlling pressure of reducing agent that is injected via additional valve, in accordance with change of flow rate of exhaust gas

摘要

The system (1) has a supply pump (5) sucking a reducing agent from a tank (4) and delivering the reducing agent. An additional valve (7) is attached at an exhaust gas pipe (6) and the reducing agent that is delivered via the supply pump and is injected into an internal section of the gas pipe. A control device (8) is provided for controlling pressure of the agent that is injected via the additional valve, in accordance with a change of a flow rate of an exhaust gas. The control device changes the pressure of the agent, while changing the quantity of the agent.