Patent ID: 8850799

Claim:
An exhaust purification apparatus for an engine, comprising: an exhaust purification element provided to an exhaust pipe of the engine; a temperature sensor adapted to measure a temperature of exhaust gas that flows into the exhaust purification element; and a control unit having a built-in computer, wherein the control unit is programmed to estimate a discharge amount of a predetermined fuel component to be discharged per unit time, the predetermined fuel component being contained in the exhaust gas, estimate an amount of the fuel component to be removed per unit time that corresponds to an exhaust gas temperature measured by the temperature sensor, by referencing to a map that sets out amounts of the fuel component to be removed per unit time corresponding to temperatures of the exhaust gas, wherein, in the map, an amount of the fuel component to be removed per unit time gradually increases as the exhaust gas temperature becomes higher than a temperature at which the fuel component is removed, and is set to zero in a region in which the exhaust gas temperature is lower than or equal to the temperature at which the fuel component is removed, and estimate an accumulation amount of the fuel component accumulated in the exhaust purification element, based on the discharge amount and the amount of the fuel component to be removed per unit time.