Abstract: An exhaust gas purification device comprises a NOx catalyst for purifying NOx contained in exhaust gas by using ammonia as a reducing agent, an ammonia supply device for supplying ammonia to the NOx catalyst, a catalyst temperature sensor for detecting the internal temperature of the NOx catalyst, and a control unit that stops the ammonia supply from the ammonia supply device when the stop condition is satisfied that the internal temperature of the NOx catalyst becomes equal to or higher than first prescribed temperature in the process where ammonia is supplied from the ammonia supply device to the NOx catalyst.

Abstract: An exhaust gas purifying system reliably detects an amount of accumulated particulates, lengthens forced regeneration intervals, and improves fuel efficiency. The exhaust gas purifying system comprises: a particulate filter 22 disposed in an exhaust system of an internal combustion engine 2 and collecting particulates from exhaust gas, and an NO2 generating unit 21 upstream of or in the particulate filter 22; a discharged particulate amount calculating unit A1 calculates an amount Me of discharged particulates on the basis of an excess air ratio ?; a burnt particulate amount calculating unit A2 calculates an amount Mb of burnt particulates on the basis of the temperature of exhaust gas in front of the particulate filter or the temperature of the particulate filter; and a particulate accumulation amount calculating unit calculates an amount Ma of accumulated particulates on the basis of the amount Me of discharged particulates or the amount Mb of burnt particulates.

Abstract: An exhaust gas purification device comprises a NOx catalyst for purifying NOx contained in exhaust gas by using ammonia as a reducing agent, an ammonia supply device for supplying ammonia to the NOx catalyst, a catalyst temperature sensor for detecting the internal temperature of the NOx catalyst, and a control unit that stops the ammonia supply from the ammonia supply device when the stop condition is satisfied that the internal temperature of the NOx catalyst becomes equal to or higher than first prescribed temperature in the process where ammonia is supplied from the ammonia supply device to the NOx catalyst.

Abstract: An exhaust gas purification system includes an oxygen mass flow rate detecting unit for detecting or calculating a mass flow rate of oxygen fed to a filter and a regeneration end determining unit for determining a regeneration end of the filter in accordance with information provided from the oxygen mass flow rate detecting-unit and upon arrival of an integrated value of the oxygen mass flow rate at a predetermined value during regeneration of the filter.

Abstract: An exhaust gas purifying system reliably detects an amount of accumulated particulates, lengthens forced regeneration intervals, and improves fuel efficiency. The exhaust gas purifying system comprises: a particulate filter 22 disposed in an exhaust system of an internal combustion engine 2 and collecting particulates from exhaust gas, and an NO2 generating unit 21 upstream of or in the particulate filter 22; a discharged particulate amount calculating unit A1 calculates an amount Me of discharged particulates on the basis of an excess air ratio ?; a burnt particulate amount calculating unit A2 calculates an amount Mb of burnt particulates on the basis of the temperature of exhaust gas in front of the particulate filter or the temperature of the particulate filter; and a particulate accumulation amount calculating unit calculates an amount Ma of accumulated particulates on the basis of the amount Me of discharged particulates or the amount Mb of burnt particulates.

Abstract: In regenerating a filter there are performed a first additional fuel injection involving additional injection of fuel into a cylinder after a main fuel injection in an engine to raise the temperature of an oxidation catalyst and a second additional fuel injection involving fuel injection after the first additional fuel injection to supply the oxidation catalyst with the fuel, a second additional fuel injection quantity is set in accordance with an engine speed and an engine load and is changed in accordance with an outlet temperature of the oxidation catalyst.

Abstract: An oxidation catalyst apparatus and a particulate collecting filter are provided sequentially from an upstream side in an exhaust gas passage of a diesel engine. A ratio of the weight of Pd to a sum of the weights of Pt and Pd carried on the oxidation catalyst apparatus is satisfactory with the following inequality: 0.05?Pd/(Pt+Pd)?0.75. When the rise of the temperature of the particulate collecting filter is needed, fuel is supplied into the oxidation catalyst apparatus.

Abstract: The present invention comprises an oxygen mass flow rate detecting means for detecting or calculating a mass flow rate of oxygen fed to a filter and a regeneration end determining means for determining a regeneration end of the filter in accordance with information provided from the oxygen mass flow rate detecting means and upon arrival of an integrated value of the oxygen mass flow rate at a predetermined value during regeneration of the filter.

Abstract: In regenerating a filter there are performed a first additional fuel injection involving additional injection of fuel into a cylinder after a main fuel injection in an engine to raise the temperature of an oxidation catalyst and a second additional fuel injection involving fuel injection after the first additional fuel injection to supply the oxidation catalyst with the fuel, a second additional fuel injection quantity is set in accordance with an engine speed and an engine load and is changed in accordance with an outlet temperature of the oxidation catalyst.

Abstract: A NOx catalyst for selectively reducing NOx in exhaust gas by adsorbing ammonia is provided at an exhaust system of an engine, ammonia or urea water is supplied to the NOx catalyst by reducing agent supplying means, a consumption amount of ammonia adsorbed to the NOx catalyst is derived by consumption amount deriving means based on an exhaust amount of NOx exhausted from the engine detected or estimated by NOx exhaust amount deriving means and an actual NOx cleaning rate by the NOx catalyst derived by actual NOx cleaning rate deriving means, an actual adsorption amount of ammonia adsorbed to the NOx catalyst is derived in accordance with an addition amount of ammonia and the consumption amount of ammonia by adsorption amount deriving means and the reducing agent supplying means is controlled by controlling means in accordance with the actual adsorption amount.

Abstract: An NOx catalyst 17 for selectively reducing NOx in exhaust gas by adsorbing ammonia is provided at an exhaust system of an engine 1, ammonia or urea water is supplied to the NOx catalyst by reducing agent supplying means 29, a consumption amount of ammonia adsorbed to the NOx catalyst is derived by consumption amount deriving means 43 based on an exhaust amount of NOx exhausted from the engine detected or estimated by NOx exhaust amount deriving means 41 and an actual NOx cleaning rate by the NOx catalyst derived by actual NOx cleaning rate deriving means 42, an actual adsorption amount of ammonia adsorbed to the NOx catalyst is derived in accordance with an addition amount of ammonia and the consumption amount of ammonia by adsorption amount deriving means 45 and the reducing agent supplying means is controlled by controlling means 46 in accordance with the actual adsorption amount.