摘要:
In cases where an NOx selective reduction catalyst is provided at a location downstream of an NOx storage reduction catalyst, NOx purification performance in an exhaust gas purification apparatus as a whole is maintained, irrespective of deterioration of the NOx storage reduction catalyst. For this purpose, the reduction of NOx in the NOx storage reduction catalyst is promoted more when the degree of deterioration of the NOx storage reduction catalyst or the NOx selective reduction catalyst is low than when it is high, and the reduction of NOx in the NOx selective reduction catalyst is promoted more when the degree of deterioration of the NOx storage reduction catalyst or the NOx selective reduction catalyst is high than when it is low.
摘要:
In cases where an NOx selective reduction catalyst is provided at a location downstream of an NOx storage reduction catalyst, NOx purification performance in an exhaust gas purification apparatus as a whole is maintained, irrespective of deterioration of the NOx storage reduction catalyst. For this purpose, the reduction of NOx in the NOx storage reduction catalyst is promoted more when the degree of deterioration of the NOx storage reduction catalyst or the NOx selective reduction catalyst is low than when it is high, and the reduction of NOx in the NOx selective reduction catalyst is promoted more when the degree of deterioration of the NOx storage reduction catalyst or the NOx selective reduction catalyst is high than when it is low.
摘要:
In cases where at the upstream side of an NOx selective reduction catalyst there is provided another catalyst, sulfur poisoning of both the catalysts is recovered in an appropriate manner. To this end, provision is made for an NH3 generation catalyst arranged in an exhaust passage of an internal combustion engine for generating NH3, the NOx selective reduction catalyst arranged in the exhaust passage at a location downstream of the NH3 generation catalyst for reducing NOx in a selective manner, an upstream side recovery unit to recover sulfur poisoning of the NH3 generation catalyst, and a downstream side recovery unit to recover sulfur poisoning of the NOx selective reduction catalyst after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit.
摘要:
In cases where at the upstream side of an NOx selective reduction catalyst there is provided another catalyst, sulfur poisoning of both the catalysts is recovered in an appropriate manner. To this end, provision is made for an NH3 generation catalyst arranged in an exhaust passage of an internal combustion engine for generating NH3, the NOx selective reduction catalyst arranged in the exhaust passage at a location downstream of the NH3 generation catalyst for reducing NOx in a selective manner, an upstream side recovery unit to recover sulfur poisoning of the NH3 generation catalyst, and a downstream side recovery unit to recover sulfur poisoning of the NOx selective reduction catalyst after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit.
摘要:
An exhaust gas purification catalyst is recovered from the sulfur poisoning more appropriately. For this purpose, an exhaust gas purification apparatus for an internal combustion engine selectively executes first control in which an air-fuel ratio of an exhaust gas allowed to flow into an exhaust gas purification catalyst is set to be not more than a theoretical air-fuel ratio to remove a sulfur component from the exhaust gas purification catalyst; and second control in which the air-fuel ratio of the exhaust gas allowed to flow into the exhaust gas purification catalyst is set to an air-fuel ratio that is lower than the air-fuel ratio of the exhaust gas set in the first control to remove the sulfur component from the exhaust gas purification catalyst; wherein the exhaust gas purification apparatus for the internal combustion engine comprises a control unit which executes any one of the first control and the second control on the basis of at least one of purification performance of the exhaust gas purification catalyst, a travel distance of a vehicle that carries the internal combustion engine, and a number of times of removal of the sulfur component from the exhaust gas purification catalyst.
摘要:
An exhaust emission control device of an internal combustion engine capable of effectively restoring an NSR catalyst from sulfur poisoning while suppressing reduction of fuel efficiency and worsening of emission, in the internal combustion engine including the NSR catalyst and SCR. An exhaust emission control device of an internal combustion engine capable of a lean burn operation includes a TWC that is placed in an exhaust passage of the internal combustion engine and supports a precious metal in an inside thereof, an NSR catalyst that is placed at an exhaust downstream side of the TWC and supports a precious metal and a base in an inside thereof, and an SCR that is placed in the exhaust passage at a downstream side of the NSR catalyst, wherein the NSR catalyst is placed in a region in which a bed temperature at a time of an operation thereof becomes 500° C. to 750° C. The TWC and the NSR catalyst are preferably configured as an SC of a tandem structure in which the TWC and the NSR catalyst are integrated by being serially arranged.
摘要:
An accurate determination of deterioration of a NOx storage reduction catalyst. A supply device supplies a reducing agent to the NOx catalyst to change an air fuel ratio of an exhaust gas passing through the NOx catalyst, an NH3 detection device detects NH3 in the exhaust gas at the downstream side of the NOx catalyst, a control device adjusts an amount of the reducing agent so that the air fuel ratio of the exhaust gas becomes a predetermined rich air fuel ratio, and a determination device makes a determination that the NOx catalyst has deteriorated, when a detected value of the NH3 detection device becomes equal to or greater than a threshold value, at the time of supplying the reducing agent while adjusting the amount of the reducing agent so that the air fuel ratio of the exhaust gas becomes the predetermined rich air fuel ratio.
摘要:
A NOX sensor degradation detection system includes: a three-way catalyst disposed in an exhaust passageway of an internal combustion engine; a selective reduction catalyst disposed in the exhaust passageway downstream of the three-way catalyst; a NOX sensor disposed in the exhaust passageway downstream of the selective reduction catalyst; and a controller configured to execute a rich-shift process that is a process for causing air/fuel ratio of exhaust gas that flows into the three-way catalyst to become rich, and to determine that the NOX sensor has degraded on a condition that a measurement value from the NOX sensor does not reach nor exceed a threshold value within a prescribed time that follows start of the rich-shift process. A degradation detection method for use in the system is also provided.
摘要:
The determination of deterioration of a NOx storage reduction catalyst (4) is carried out more accurately. When a reducing agent is supplied from a supply device (5) to the NOx catalyst (4), a first supply of the reducing agent and a second supply of the reducing agent are carried out in a sequential manner by adjusting an amount of the reducing agent in such a manner that an air fuel ratio of the exhaust gas becomes a predetermined rich air fuel ratio, and a determination whether or not the NOx catalyst (4) has deteriorated is made based on a detected value of a detection device (8), which detects NH3 in the exhaust gas at the downstream side of the NOx catalyst (4), after a predetermined period of time has elapsed from the start of the first supply of the reducing agent, and after the start of the second supply of the reducing agent.
摘要:
The present invention has its object to provide a technique which can eliminate HC poisoning of an exhaust gas purification catalyst in a suitable manner in a fuel injection control system of an internal combustion engine which can use a liquid fuel and a gas fuel. In order to achieve this object, the present invention is constructed such that in the fuel injection control system of an internal combustion engine capable of using a liquid fuel and a gas fuel, when HC poisoning of the exhaust gas purification catalyst has occurred, HC poisoning is intended to be eliminated by causing the internal combustion engine to operate by the use of the gas fuel if the temperature of the exhaust gas purification catalyst is less than a specified value, whereas the elimination of HC poisoning is intended by causing the internal combustion engine to operate by the use of the liquid fuel if the temperature of an exhaust gas purification device is not less than the specified value.