Abstract: An object of the present invention is to increase the flexibility in the layout of an exhaust gas purification system for an internal combustion engine including selective catalytic reduction catalyst provided in an exhaust passage of the internal combustion engine and an addition device for supplying reducing agent derived from ammonia to the selective catalytic reduction catalyst, without a deterioration of the performance in reducing nitrogen oxides. To achieve the object, the exhaust gas purification system for an internal combustion engine according to the present invention is configured to supply hydrocarbon at the same time when reducing agent derived from ammonia is supplied to the selective catalytic reduction catalyst, thereby producing reducing agent that is hard to be oxidized by a precious metal catalyst.

Abstract: An exhaust gas purification system is equipped with a burner in an exhaust passage upstream of an exhaust gas purification apparatus and having a burner combustion chamber in which flame is produced. When the temperature of the exhaust gas purification apparatus is raised, the burner produces flame that extends from the interior of the burner combustion chamber to the interior of the exhaust passage when the flow rate of the exhaust gas is not higher than a predetermined flow rate, and the burner causes the size of the flame to be smaller than when it is determined that the flow rate of the exhaust gas is not higher than the predetermined flow rate or to produce flame only in the interior of the burner combustion chamber when it is determined that the flow rate of exhaust gas is higher than the predetermined flow rate.

Abstract: A technique that, in an exhaust gas purification apparatus of an internal combustion engine, can avoid a decrease in a NOx purification rate by adding a reducing agent as continuously as possible, while avoiding NH3 from passing through a selective reduction type NOx catalyst to a downstream side thereof. The selective reduction type NOx catalyst has an active spot which purifies NOx by the use of NH3, and an adsorption site which adsorbs NH3, wherein a vicinity site, which is located in the vicinity of the active spot, and a distant site, which is located distant from the active spot, exist in the adsorption site. The addition of the reducing agent from the reducing agent addition part is controlled based on the desorption rate of NH3 in the vicinity site so as to continue to cause the NH3 adsorbed to the vicinity site to exist.

Abstract: In an internal combustion engine, an NOX selective reducing catalyst is arranged in an engine exhaust passage. Urea is fed in the NOX selective reducing catalyst, ammonia generated from this urea is adsorbed at the NOX selective reducing catalyst, and the NOX contained in the exhaust gas is selectively reduced mainly by the adsorbed ammonia. An NOX sensor able to detect NOX and ammonia contained in the exhaust gas is arranged in the engine exhaust passage downstream of the NOX selective reducing catalyst. It is judged that the amount of adsorption of ammonia at the NOX selective reducing catalyst is saturated based on the detection value of the NOX sensor when the feed of fuel to the engine is stopped during the deceleration operation.

Abstract: In an internal combustion engine, an NOx selective reduction catalyst (14) is arranged in an engine exhaust passage, and an NOx storage catalyst (12) is arranged in the engine exhaust passage upstream of the NOx selective reduction catalyst (14). When the amount of NOx stored in the NOx storage catalyst (12) exceeds a predetermined allowable value, the NOx storage catalyst (12) is raised in temperature to make the NOx storage catalyst (12) release the NOx. The amount of urea feed is decreased by exactly the amount of reduction of the calculated stored NOx amount with respect to the amount of urea feed determined from the engine operating state, and the amount of urea feed is increased by exactly the amount of reduction of the calculated released NOx amount with respect to the amount of urea feed determined from the engine operating state.

Abstract: An exhaust purification system of an internal combustion engine that includes a NOx catalyst device which has a reducing material holding ability for holding reducing material and can reduce NOx by using the reducing material; and an electronic control unit that includes program logic, which when executed, determines whether or not a difference between a target amount of reducing material held by the NOx catalyst device and a current amount of reducing material held by the NOx catalyst device is larger than a set amount; and performs a first control or a second control.

Abstract: An internal combustion engine wherein when an aqueous urea solution should be fed from an aqueous urea solution feed valve (8), a feed pump (9) is operated forward and aqueous urea solution in an aqueous urea solution tank (4) is fed through an aqueous urea solution feed passage (10) into the aqueous urea solution feed valve (8). When ceasing the feed of aqueous urea solution from the aqueous urea solution feed valve (8), the feed pump (9) is operated in reverse whereby the ammonia gas generated in the aqueous urea solution tank (4) is drawn through a ammonia gas feed pipe (11) into the aqueous urea solution feed passage (10). Next, when the feed pump (9) is operated forward, the ammonia gas drawn into the aqueous urea solution feed path (10) is ejected from the aqueous urea solution feed valve (8).

Abstract: In an internal combustion engine, a urea adsorption type selective reduction catalyst is arranged in an engine exhaust passage. By feeding urea from a urea feed valve into the exhaust gas flowing into this selective reduction catalyst, the NOx included in the exhaust gas is reduced in the selective reduction catalyst. TO suppress the generation of hydrogen cyanide, an HC adsorption catalyst for adsorption of the HC in the exhaust gas is arranged in the engine exhaust passage upstream of the selective reduction catalyst.

Abstract: An object of the invention is to estimate the quantity of N2O produced in an ammonia oxidation catalyst in a case where the ammonia oxidation catalyst is provided in an exhaust passage of an internal combustion engine. In a case where an ammonia oxidation catalyst having the function of oxidizing ammonia is provided in an exhaust passage of an internal combustion engine, the quantity of N2O produced in the ammonia oxidation catalyst is estimated based on the difference between a measurement value of an upstream NOx sensor provided in the exhaust passage upstream of the ammonia oxidation catalyst and a measurement value of a downstream NOx sensor provided in the exhaust passage downstream of the ammonia oxidation catalyst.

Abstract: In an internal combustion engine, an NOx selective reduction catalyst is arranged in the engine exhaust passage, and a urea aqueous solution feed valve is arranged in the engine exhaust passage upstream of the NOx selective reduction catalyst. Based on the detections results of an NOx purification rate detecting means for detecting the NOx purification rate by the NOx selective reduction catalyst, a urea aqueous solution feed amount detecting means for detecting the amount of feed of the urea aqueous solution, and a urea aqueous solution concentration detecting means for detecting the concentration of the urea aqueous solution, abnormalities in the NOx selective reduction catalyst, urea aqueous solution feed system, and urea aqueous solution are judged.

Abstract: An object of the present invention is to suppress, in a system in which an NOx selective catalytic reduction catalyst and a particulate filter are provided in an exhaust passage of an internal combustion engine, discharge of ammonia from the NOx selective catalytic reduction catalyst. In the exhaust gas purification system for an internal combustion engine according to the present invention, when a condition for executing a filter temperature raising control is satisfied, the supply of urea to the NOx selective catalytic reduction catalyst by urea supply means is stopped, and the filter temperature raising control is executed by filter temperature raising means after a specific time has elapsed since the time of stoppage of the supply of urea to the NOx selective catalytic reduction catalyst.

Abstract: In an internal combustion engine, an NOx selective reduction catalyst is arranged in the engine exhaust passage and a urea aqueous solution stored in a urea aqueous solution tank is fed to the NOx selective reduction catalyst where the NOx is selectively reduced. Opening and closing of the urea aqueous solution refill port of the urea aqueous solution tank are detected and it is judged if the urea aqueous solution is refilled in the urea aqueous solution tank. When it is judged that the NOx purification rate has fallen to an allowable level or less at the time of engine operation right after the urea aqueous solution is refilled in the urea aqueous solution tank, it is judged that the refilled urea aqueous solution is abnormal.

Abstract: The task for the present invention is to reduce more of an oxide that is stored in a NOx storage reduction catalyst, even in a case where a clogging has occurred in a reducing agent adding valve that is provided in an exhaust passage of an internal combustion engine. The present invention is provided with rich spike control performing means that, when an oxide that is stored in the NOx storage reduction catalyst is reduced, performs a rich spike control and that, when lowering the air-fuel ratio in the exhaust gas, performs addition of a reducing agent by the reducing agent adding valve multiple times, which is performed when a crank angle of the internal combustion engine is in a specified range. When the clogging has occurred in the reducing agent adding valve, the number of times the air-fuel ratio in the exhaust gas is lowered while the rich spike control is being performed by the rich spike control performing means is increased.

Abstract: An exhaust purifying device for an internal combustion engine which can restrict an influence of a measurement error in a NOx sensor provided at the downstream side of a catalyst and can optimally maintain a NOx purifying rate. The device includes a catalytic converter carrying a selective catalytic reduction catalyst provided in an exhaust passage of the engine to selectively reduce nitrogen oxides, a urea water adding valve for adding urea water to the catalyst as a reducing agent, a NOx sensor provided at the downstream side of the catalyst, and an ECU for adjusting an addition amount of the urea water adding valve based upon output of the NOx sensor, wherein a urea water addition amount adjusting process is executed under a condition that a NOx amount to be generated in the engine increases.

Abstract: The present invention comprises a selective reduction type NOx catalyst located in an exhaust passage and being capable of purifying NOx with ammonia, an oxidation catalyst located downstream of the selective reduction type NOx catalyst, an upstream sensor located between the selective reduction type NOx catalyst and the oxidation catalyst and having ability to detect both ammonia and NOx, a downstream sensor located downstream of the oxidation catalyst and having ability to detect both ammonia and NOx, and determining means for determining a component passing through the selective reduction type NOx catalyst, based upon a relation between output of the upstream sensor and output of the downstream sensor.

Abstract: The present invention provides an exhaust purification apparatus for an internal combustion engine which enables a decrease in NOx purification rate and possible ammonia slip to be inhibited. The apparatus includes an NOx catalyst, a urea aqueous solution addition valve serving as reducing agent adding means, and NOx sensors provided an inlet and an outlet of the NOx catalyst, respectively. When the bed temperature of the NOx catalyst is in a predetermined high-temperature region in which the amount of ammonia converted into NOx increases relatively and an NOx purification rate decreases relatively, the apparatus uses outputs from the NOx sensors to perform correction such that the actual addition amount of the urea aqueous solution addition valve reaches a target addition amount.

Abstract: In an exhaust purification system of an internal combustion, comprising a NOX catalyst device which has a reducing material holding ability to hold reducing material and can reduce NOX by using of reducing material, a first control, in which an amount of reducing material of the equivalence ratio over 1 for an amount of NOX in the exhaust gas flowing into the NOX catalyst device is supplied to the NOX catalyst device until the reducing material holding ability holds a preset target amount of reducing material, is carried out and a second control, in which in spite of an amount of reducing material held by the reducing material holding ability, an amount of reducing material of the equivalence ratio of a predetermined value for an amount of NOX in the exhaust gas flowing into the NOX catalyst device is supplied to the NOX catalyst device, is carried out from when the first control has been carried out to when the next first control will be carried out.

Abstract: When a fuel as a reducing agent is supplied to a NOx catalyst on which a NOx or a SOx is reduced, a flow rate of exhaust gas that flows through an exhaust passage is changed, and the fuel is supplied to the exhaust gas flowing through the exhaust passage at a plurality of timings (?T1, ?T2) when the exhaust gas flows at different flow rates.

Abstract: A device for purifying exhaust gas of an internal combustion engine is provided, equipped with an HC catalyst having the ability to oxidize HC, as well as adsorb HC, and release HC which it has adsorbed, and there exists a specific condition where the amount to release HC becomes greater than the amount to oxidize HC, wherein the device for purifying exhaust gas of an internal combustion engine executes an HC feed control for feeding HC to the HC catalyst. The amount of HC fed to the HC catalyst is decreased by the HC feed control or the HC feed control is discontinued when the specific condition is established during execution of the HC feed control.

Abstract: An exhaust emission control system of an internal combustion engine desorbs SOx by reversing a flow of an exhaust gas through an NOx storage-reduction catalyst, of which a structure is simplified as follows. A first exhaust pipe connected to an engine is connected to a first port of an emission switching valve having four ports. A second exhaust pipe 10, through which the exhaust gas is discharged into the atmospheric air, is connected to a second port, a third exhaust pipe connected to an inlet of a catalytic converter is connected to a third port. A fourth exhaust pipe connected to an outlet of the catalytic converter 30 is connected to a fourth port. When the emission switching valve is set in a forward flow position, the first exhaust pipe is connected to the third exhaust pipe, and the second exhaust pipe is connected to the fourth exhaust pipe, whereby the exhaust gas flows toward the outlet from the inlet within the catalytic converter.