EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To prevent the lowering of exhaust purifying efficiency due to the generation of low temperature poisoning caused by SOF and a reducing agent in exhaust, to an NOx absorbent for eliminating NOx in the exhaust gas of a diesel engine. CONSTITUTION:An exhaust passage 3 downstream of an NOx absorbent 15 is provided with an oxygen concentration sensor 10 for detecting the oxygen concentration of exhaust so as to detect the concentration of oxygen after the lapse of the specified time from the time of starting the execution of regenerating operation. An ECU 20 judges the low temperature poisoning of the NOx absorbent to be generated in the case of the oxygen concentration being higher than the specified value, and performs poisoning recovery processing for burning SOF and the like stuck to the NOx absorbent 15 by heating the NOx absorbent 15 by an electric heater or the like.