DEVICE FOR DETECTING SULFUR COMPONENT

摘要

Disclosed is a device for detecting sulfur components, the device being equipped with: a holding part which holds SOx and NOx contained in an exhaust gas passing through an exhaust gas passage and decreases in NOx holding capacity as the amount of held SOx increases and which releases only the held NOx when the air-fuel ratio of the exhaust gas is set to a theoretical air-fuel ratio or a rich air-fuel ratio, the released NOx being reduced; and a temperature sensor which measures the temperature of the holding part. In the device, the increase in the temperature of the holding part which occurs upon the reduction reaction of the released NOx is measured by the temperature sensor, and the quantity of exothermic heat during the reduction reaction of the released NOx is calculated on the basis of the measured temperature increase and the heat capacity of the holding part to thereby calculate the NOx release amount corresponding to the NOx holding capacity and estimate the current amount of held SOx. The integrated amount of SOx which has passed through the exhaust gas passage in a certain period or a value based on the integrated amount is determined. The device is further equipped with a heater that heats the holding part. The current heat capacity (C) of the holding part is determined (step 209) from the temperature increase (T2-T1) of the holding part which was measured by the temperature sensor when the holding part was heated by the heater (step 204) and from the quantity of heat (QH) generated by the heater.