EXHAUST EMISSION CONTROL DEVICE OF DIESEL ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device of a diesel engine which can improve durability and reliability of an additional injector, and can also inhibit accumulation of deposits.

SOLUTION: The exhaust emission control device includes: a DPF 25 provided in an exhaust conduit 22 of an engine 11; the additional injector for addition of fuel provided on a more upstream side portion of the exhaust conduit 22 rather than the DPF 25: a cooling water circulation passage 38 circulating part of the cooling water of the engine to cool it; and a control valve 37 provided in a conduit 35 of the cooling water circulation passage 38 and controlling a flow of the cooling water. An ECU 39 controls the control valve 37 to minimalize opening of the control valve 37, when the exhaust temperature is a reference temperature or less and the exhaust flow rate is a reference exhaust flow rate or less in such a way that the accumulation of the deposits around a place where the additional injector of the exhaust conduit 22 is provided is inhibited based on an exhaust temperature detected by a temperature sensor 30 and an exhaust flow rate detected by an air flow meter 24.

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