| abstract |
Provided is an exhaust gas purifying device for an internal combustion engine that can improve atomization of a reducing agent and ensure combustion air reliably. The controller in the exhaust gas purification device also controls the variable exhaust turbo nozzle opening for spraying urea water, so the engine is in the low load range of T1 to T2 and normally the boost pressure does not increase However, it is possible to obtain a supercharging pressure P suitable for the spraying of urea water by controlling the opening degree of the variable exhaust turbo nozzle so that it is more closed than usual (two-dot chain line). A part of urea water can be atomized reliably. Further, by increasing the supercharging pressure to P, the combustion air supplied to the engine increases, so that good combustion can be realized, and generation of particulates and discharge of unburned fuel can be suppressed. |