Abstract: The present invention provides an internal combustion engine exhaust purification apparatus includes a filter configured to collect particulate matter contained in exhaust gas, a selective catalytic reduction converter provided downstream of the filter to reduce nitrogen oxide contained, an oxidation catalyst converter with an adsorption function provided upstream of the converter to temporarily adsorb the nitrogen oxide contained in the exhaust gas, a burner configured to increase the temperature of the exhaust gas flowing into the filter, the selective catalytic reduction converter, and the oxidation catalyst converter to set the temperature of the filter to at least a predetermined recovery temperature, thus recovering the filter, and an ECU configured to inhibit the burner from being started when the burner is otherwise to be started but if the selective catalytic reduction converter has not been activated.

Abstract: In an internal combustion engine, a first exhaust passage and second exhaust passage branched from an exhaust passage are provided. An NOx storing reduction catalyst and a particulate filter are arranged in each exhaust passage. For example, when NOx should be released from the NOx storing reduction catalyst in the first exhaust passage, fuel is added from a fuel addition valve in the state with exhaust gas allowed to flow into only the first exhaust passage, while when the added fuel sticks to the NOx storing reduction catalyst, the first exhaust control valve is temporarily closed and the exhaust gas is made a rich air-fuel ratio.

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: 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 exhaust emission control system of an internal combustion engine, a NOx selective reduction catalyst is disposed in an engine exhaust passage, and an aqueous solution of urea stored in an aqueous-urea tank is supplied to the NOx selective reduction catalyst so as to selectively reduce NOx. A NOx sensor is provided in the engine exhaust passage downstream of the NOx selective reduction catalyst for detecting the NOx conversion efficiency of the NOx selective reduction catalyst, and the concentration of aqueous urea in the aqueous-urea tank is estimated from the detected NOx conversion efficiency. The exhaust emission control system and method make it possible to detect the concentration of aqueous urea at reduced cost.

Abstract: The invention has an object of exerting favorable NOx reducing effects even at an exhaust temperature lower than in the prior art without trouble, e.g., at startup after long-term engine rest and is directed to an exhaust emission control device wherein a selective reduction catalyst 5 capable of selectively reacting NOx with ammonia even in the presence of oxygen is incorporated in an exhaust pipe 4, urea water 6 as reducing agent being added in the pipe 4 upstream of the reduction catalyst 5 to depurate NOx through reduction.

Abstract: The present invention provides a technology enabling regeneration of the purification performance of an exhaust purification device more reliably and more efficiently in an exhaust purification system combining a plurality of branch passages bifurcating from an exhaust passage and an exhaust purification device provided in each branch passage. When regenerating the purification performance of a first exhaust purification device provided in a first branch passage, a second valve provided in a second branch passage is set at a predetermined first intermediate opening and a first valve provided in the first branch passage is fully closed. Fuel is then added from a first fuel addition valve provided in the first branch passage.

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: 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: A fuel adding valve (14), an HC adsorbing and oxidation catalyst (11), and a NOx storing catalyst (12) are successively arranged in an exhaust passage of an internal combustion engine toward the downstream side. When the NOx storing catalyst (12) should release NOx, particulate fuel is added from the fuel adding valve (14). This fuel is adsorbed once at the HC adsorbing and oxidation catalyst (11), then gradually evaporates to make the air-fuel ratio of the exhaust gas flowing into the NOx storing catalyst (12) rich. Due to this, NOx is released from the NOx storing catalyst (12).

Abstract: An exhaust gas purifying apparatus for an internal combustion engine comprises a casing which forms a part of an exhaust passage of the internal combustion engine and houses therein an occlusion-reduction type NOx catalyst and a reducing agent supply device which supplies a reducing agent to an interior of the casing on an upstream side of the NOx catalyst. The reducing agent supply device injects the reducing agent in a flat form in a direction intersecting a center line of the NOx catalyst from a nozzle hole disposed in the casing.

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: In an internal combustion engine, an NOx selective reduction catalyst (15) is arranged in the engine exhaust passage, and the amount of deposition of the HC deposited at the NOx selective reduction catalyst (15) is estimated. When the estimated HC deposition amount exceeds a predetermined allowable deposition amount, the NOx selective reduction catalyst (15) is raised in temperature to make the deposited HC desorb from the NOx selective reduction catalyst (15), and thereby the NOx selective reduction catalyst (15) from HC poisoning is restored.

Abstract: A catalyst suitable for reducing NOx in exhaust gas by ammonia in the presence of excess oxygen is arranged in an engine exhaust passage. The catalyst is fed an aqueous urea solution from an addition control valve, part of the urea fed to the catalyst is stored in the catalyst, and the ammonia produced from the urea stored in the catalyst is used to reduce the NOx in the exhaust gas. It is judged whether the storage capacity of the catalyst is larger than a preset allowable upper limit capacity. When it is judged that the storage capacity of the catalyst is larger than the allowable upper limit capacity, the feed of the aqueous urea solution is prohibited.

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 (15) is arranged in the engine exhaust passage and a urea aqueous solution stored in a urea aqueous solution tank (20) is fed to the NOx selective reduction catalyst (15) where the NOx is selectively reduced. Opening and closing of the urea aqueous solution refill port (40) of the urea aqueous solution tank (20) are detected and it is judged if the urea aqueous solution is refilled in the urea aqueous solution tank (20). 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 (20), it is judged that the refilled urea aqueous solution is abnormal.

Abstract: In an internal combustion engine, an NOx selective reducing catalyst (15) is arranged in an engine exhaust passage and an oxidation catalyst (12) is arranged in the engine exhaust passage upstream of the NOx selective reducing catalyst (15). At the time of engine startup, HC is fed from a HC feed valve (28) to the oxidation catalyst (12), thereby raising the temperature of the NOx selective reducing catalyst(15) by the heat of the oxidation reaction of HC. At this time, the temperature of the NOx selective reducing catalyst (15) is raised to a HC desorption range where HC is desorbed from the NOx selective reducing catalyst (15).

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 internal combustion engine, in which an NOx selective reducing catalyst (15) is arranged inside an engine exhaust passage, and aqueous urea stored in an aqueous urea tank (20) is fed to the NOx selective reducing catalyst (15) to selectively reduce the NOx. The aqueous urea tank (20) comprises a main tank (20a) and a sub tank (20b) arranged inside the main tank (20a). The aqueous urea in the sub tank (20b) is sent to an aqueous urea feed valve (17). When the aqueous urea tank (20) should be refilled with aqueous urea, the sub tank (20b) is refilled with aqueous urea. It is detected by a level sensor (40) if the aqueous urea in the aqueous urea tank (20) is refilled. When it is judged that the NOx purification rate falls below an allowable level at the time of engine operation right after the aqueous urea in the aqueous urea tank (20) has been refilled, it is judged that the refilled aqueous urea is abnormal.