Abstract: An SOx trap catalyst able to trap SOx contained in the exhaust gas is arranged in an engine exhaust passage upstream of an NOx storing catalyst in an internal combustion engine. When the SOx trap rate of the SOx trap catalyst falls, fuel is added in the exhaust gas flowing into the SOx trap catalyst to form in the SOx trap catalyst a region in which an air-fuel ratio becomes locally rich. SOx released from the SOx trap catalyst in this region can be trapped in the SOx trap catalyst at the downstream side once again without flowing out from the downstream end of the SOx trap catalyst.

Abstract: The present detector for detecting sulfur components includes a storage portion for storing SOx and NOx in the exhaust gas passing through an exhaust passage, in which the more an amount of stored SOx increases, the more an amount of NOx that can be stored decreases, estimates the amount of stored SOx on the basis of an amount of NOx stored in the storage portion, and detects an integrated amount of SOx passing through the exhaust passage during a given period or an value on the basis of the integrated amount. In the present detector, the estimating of the amount of stored SOx for detecting the integrated amount of SOx or the value on the basis of the integrated amount is prohibited when a current amount of NOx that can be stored is not stored in the storage portion.

Abstract: In an exhaust purification system of an internal combustion engine comprising an exhaust purification device which receives a bad influence from SOX in the exhaust gas and a S trap device arranged upstream of the exhaust purification device, which can store SOX in the exhaust gas, an amount of SOX passing through the S trap device is integrated as an integrated value, each allowance value of the integrated value for each elapsed period from the start time of the use of the S trap device is set, and when the current integrated value exceeds the corresponding allowance value and between a first set period ago and the current time, fuel has been supplied into the fuel tank and engine oil has not been exchanged, it is determined that fuel with a high concentration of sulfur has been supplied into the fuel tank.

Abstract: In the present exhaust purification system of an internal combustion engine, a particulate filter is arranged downstream of an NOx storage/reduction catalyst device and an S trap device is arranged upstream of the NOx storage/reduction catalyst device. A first fuel supplying device for supplying additional fuel for regeneration of the particulate filter to the exhaust system upstream of the S trap device or into the cylinder is provided. An amount of the additional fuel supplied by the first fuel supplying device is controlled to make the S trap device not release SOx. A second fuel supplying device is provided in the exhaust system between the NOx storage/reduction catalyst device and the particulate filter to make up for a deficiency of the additional fuel supplied by the first fuel supplying device in the regeneration treatment of the particulate filter.

Abstract: The present detector for detecting sulfur components includes a storage portion for storing SOx and NOx in the exhaust gas passing through an exhaust passage, in which the more an amount of stored SOx increases, the more an amount of stored NOx decreases, and which does not release SOx but release NOx at a set temperature, and a temperature sensor, estimates the amount of stored SOx on the basis of a relationship between, after the storage portion becomes the set temperature by heating, a heating pattern of the storage portion and temperature change of the storage portion measured by the temperature sensor, and detects an integrated amount of SOx passing through the exhaust passage during a given period or an value on the basis of the integrated amount.

Abstract: An internal combustion engine in which an SOx trap catalyst for trapping SOx contained in the exhaust gas is comprised of an upstream side catalyst and a downstream side catalyst into which the exhaust gas flowing out from the upstream side catalyst flows. The SOx storing material of the upstream side catalyst is mainly comprised of an alkali earth metal, while the SOx storing material of the downstream side catalyst is mainly comprised of an alkali metal.

Abstract: The exhaust purification system of an internal combustion engine of the present invention is provided with an NOX storage reduction catalyst and a particulate filter which is arranged at the upstream side of the NOX storage reduction catalyst. When causing the NOX storage reduction catalyst to release the stored NOX, the particulate filter is raised to the temperature at which the particulate matter is oxidized, the flow rate of the exhaust gas which flows into the particulate filter is made to decrease, the air-fuel ratio of the exhaust gas which flows into the particulate filter is made rich, and the particulate matter which builds up on the particulate filter is made to oxidize to produce carbon monoxide.

Abstract: An exhaust purification system of an internal combustion engine has a selective reduction type NOX catalyst device which can hold ammonia and a storage reduction type NOX catalyst device which is arranged at an upstream side of the selective reduction type NOX catalyst device, which makes an air-fuel ratio of exhaust gas which flows into the storage reduction type NOX catalyst device change from a lean air-fuel ratio to a rich air-fuel ratio for starting an ammonia generation period, and which makes an air-fuel ratio of exhaust gas which flows into the storage reduction type NOX catalyst device change from a rich air-fuel ratio to a lean air-fuel ratio for ending the ammonia generation period.

Abstract: An internal combustion engine wherein an NOx storing catalyst is arranged in an engine exhaust passage and an NOx selective reducing catalyst is arranged downstream of the NOx storing catalyst. Just before the air-fuel ratio of the exhaust gas flowing into the NOx storing catalyst is temporarily switched from lean to rich to release NOx from the NOx storing catalyst, an amount of NOx necessary for removing ammonia adsorbed on the NOx selective reducing catalyst is fed to the NOx selective reducing catalyst under a lean air-fuel ratio.

Abstract: An internal combustion engine in which an SOx trap catalyst (13) for trapping SOx contained in the exhaust gas contains an oxygen adsorbing and releasing material (54) which can adsorb SO2 contained in the exhaust gas and an SOx storage material (55) which can store SOx in the form of sulfates. The SO2 which is contained in the exhaust gas is chemically adsorbed at the oxygen adsorbing and releasing material (54) without being oxidized. If the temperature of the SOx trap catalyst (13) becomes higher than the start temperature of adsorbed SO2 movement, the SO2 which is chemically adsorbed at the oxygen adsorbing and releasing material (54) is oxidized and stored in the form of sulfates in the SOx storage material (55).

Abstract: A metal or metal compound able to trap a sulfur component in exhaust gas is arranged in a flow passage of exhaust gas in an internal combustion engine. When the amount of sulfur component trapped in the metal or metal compound increases over the passage of time, a property of the metal or metal compound which changes along with the increase in the amount of trapped sulfur component is measured and the sulfur component in the gas is detected from the measured property.

Abstract: An internal combustion engine in which a front end catalyst (12) and rear end catalyst (14) comprising NOx storing catalysts are arranged in an engine exhaust passage. When these catalysts (12, 14) should recover from SOx poisoning, SOx poisoning recovery proceeding is performed in which the temperatures of the corresponding catalysts (12, 14) are raised to the SOx release temperature and the air-fuel ratio of the exhaust gas flowing into the corresponding catalysts (12, 14) is made rich. In this case, the frequency of performing the SOx poisoning recovery proceeding of the rear end catalyst (14) is made higher than the frequency of performing the SOx poisoning recovery proceeding of the front end catalyst (12).

Abstract: A metal compound (50) able to trap a sulfur component in exhaust gas is arranged in a flow path of the exhaust gas, a property of the metal compound (50) changing along with an increase of the amount of sulfur component trapped at the metal compound (50) is measured, and the cumulative value of the amount of SOX actually contained in the exhaust gas is calculated from the measured property. On the other hand, the assumed cumulative value of the amount of SOX, assumed to be contained in the exhaust gas when assuming that fuel or oil of a sulfur concentration assumed in advance is used, is calculated. It is judged if fuel or oil with a high sulfur concentration is being used from the actual cumulative value of the amount of SOX and the assumed cumulative value of the amount of SOX.

Abstract: An internal combustion engine wherein an SOx trap catalyst (12), an NOx storage catalyst (14), and a fuel addition valve (15) are arranged in an engine exhaust passage. When making the air-fuel ratio of the exhaust gas flowing into the NOx storage catalyst (14) the stoichiometric air-fuel ratio or rich so as to make the NOx storage catalyst (14) release NOx, additional fuel is supplied into the combustion chamber (2) and fuel is added from the fuel addition valve (15). At this time, the amount of additional fuel to the combustion chamber (2) is controlled so that the air-fuel ratio of the exhaust gas exhausted from the combustion chamber (2) becomes the smallest in the range where the SOx trap catalyst (12) does not release SOx.

Abstract: An exhaust purification system is provided with an NOx storage reduction catalyst arranged in an exhaust passage and an SOx trap material arranged upstream of the NOx storage reduction catalyst and removes SOx contained in exhaust gas. A main flow path has a secondary flow path connected to it. In the secondary flow path, a removal device is arranged for removing the sulfur constituent contained in fuel. The secondary flow path includes an opening and closing device. When the SOx removal rate of the SOx trap material becomes a predetermined removal rate judgment value or less or the concentration of the SOx which flows into the SOx trap material becomes a predetermined concentration judgment value or more, at least part of the fuel flowing through a main flow path is made to flow into the secondary flow path and run through the removal device.

Abstract: The exhaust purification system of an internal combustion engine is provided with an NOX selective reduction catalyst which is arranged in an engine exhaust passage and which has the function of absorbing NOX which is contained in exhaust gas when an air-fuel ratio of inflowing exhaust gas is lean, releasing the absorbed NOX when the air-fuel ratio of the inflowing exhaust gas becomes a stoichiometric air-fuel ratio or rich, and selectively reducing the NOX and with a fuel addition valve which feeds fuel to the NOX selective reduction catalyst. In the case of the region near the stoichiometric air-fuel ratio in the region where the air-fuel ratio of the exhaust gas flowing into the NOX selective reduction catalyst is lean, the fuel addition valve is used to feed fuel to the NOX selective reduction catalyst to selectively reduce the NOX.

Abstract: An SOX trap catalyst (11) in which at least one of an alkali metal and alkali earth metal is carried diffused is arranged in an exhaust passage of an internal combustion engine. By holding the temperature of the SOX trap catalyst (11) during engine operation at the temperature where a nitrate of the at least one of the alkali metal and alkali earth metal becomes the melted state, a nitrate movement and coagulation action where the nitrate in the SOX trap catalyst (11) moves to and coagulates at the surface of the SOX trap catalyst (11) is promoted. Due to this nitrate movement and coagulation action, SOX is removed while restoring the SOX trap rate.

Abstract: In an internal combustion engine, an SOx sensor (16) having a sensor part (53, 60) trapping the SOx contained in the exhaust gas and able to detect the amount of SOx trapped at the sensor part (53, 60) from a change of property of the sensor part (53, 60) is arranged in the engine exhaust passage upstream of the NOx storing catalyst (14). When estimating the amount of SOx stored in the NOx storing catalyst (14) from the amount of SOx trapped at the sensor part (53, 60), deviation of the estimated value of the amount of stored SOx arising due to the difference between the SOx trapping rate of the sensor part (53, 60) and the SOx trapping rate of the NOx storing catalyst (14) is corrected.

Abstract: In an internal combustion engine, an NOx selective reducing catalyst is arranged inside an engine exhaust passage, an oxidation catalyst is arranged upstream of the NOx selective reducing catalyst, and an NOx adsorption catalyst is arranged upstream of the oxidation catalyst. The NOx adsorption catalyst has a property of releasing NOx when the temperature rises and a property of trapping the SOx contained in the exhaust gas. The inflow of SOx into the oxidation catalyst is suppressed by the NOx adsorption catalyst to prevent the NO released from the NOx adsorption catalyst being oxidized to NO2 at the oxidation catalyst from being obstructed by SOx.

Abstract: Engine air-fuel ratio controlling means is provided to control an exhaust air-fuel ratio that is the ratio between the air contained in the exhaust gas discharged from the engine and the fuel element contained in the same exhaust gas and acting as a reducing agent at a NOx catalyst by controlling the air-fuel ratio of the gas combusted in the engine. Fuel adding means is provided upstream of the NOx catalyst in an exhaust passage to add fuel into the exhaust gas. During the SOx poisoning recovery control, when developing a state enabling SOx reduction reactions, the exhaust gas air-fuel ratio of the exhaust gas discharged from the engine and the amount of fuel added from the fuel adding means are controlled to minimize the sum of the amount of fuel injected in the engine and the amount of fuel added from the fuel adding means.