Abstract: The degree of a deterioration in catalyst is determined when the following requirements are satisfied: the operating state of an internal combustion engine (E) is in a predetermined operating state; and the temperature (T1m) of an exhaust gas, which flows into a catalyst (12), is in a second temperature range (?T80) in which the upper limit of the second temperature range (?T80) is 10% below the upper limit of a first temperature range (?T100) between the activation start temperature (Ta) and the activation end temperature (Tb) of the catalyst (12) before a deterioration and the lower limit of the second temperature range (?T80) is 10% above the lower limit of the first temperature range (?T100).

Abstract: In an exhaust gas purification system, including a catalyst unit carrying an NOx occlusion-reduction type catalyst, a first-stage rich control having a target air-fuel ratio lower than theoretical air-fuel ratio and which is conducted through addition of an amount of a reducing agent meeting an amount of oxygen emitted in the initial stage of regeneration control. In the first-stage rich control a completion of oxygen emission is judged on the basis of an oxygen concentration on the downstream side of the catalyst unit. Upon determination of the completion of the oxygen emission, a later-stage rich control close to the theoretical air-fuel ratio with the target air-fuel ratio increased over that of the first-stage rich control is conducted to thereby accomplish regeneration of the catalyst unit.

Abstract: An NOx purification system having a selective reduction catalyst, adapted so that even when no ammonia or urea is supplied, NOx is converted to ammonia by a first catalyst including a lean NOx catalyst or a ternary catalyst at ammonia formation control and the ammonia is adsorbed by the selective reduction catalyst disposed downstream and so that by the adsorbed ammonia, there is carried out reduction purification of the NOx contained in the exhaust gas when no ammonia formation control is performed by the selective reduction catalyst. At the ammonia formation control, an ammonia adsorption target amount being a target value of ammonia adsorbed by the selective reduction catalyst is computed, and the ammonia formation control is carried out only when a cumulative value of an ammonia formation amount formed by the first catalyst at the ammonia formation control is under the ammonia adsorption target amount. Consequently, ammonia is stably supplied in just proportion to the selective reduction catalyst.

Abstract: In a NOx purification system 1 provided with a NOx occlusion reduction catalyst 20 and a control unit 30 which executes a NOx regeneration control and a sulfur poisoning regeneration control, a binary ? sensor 26 and a reducing agent concentration sensor 25 for detecting a concentration of the reducing agent are disposed downstream of the NOx occlusion reduction catalyst 20. The level of deterioration of the NOx occlusion reduction catalyst 20 caused by sulfur poisoning is estimated on the basis of a time period Ta from a time point T3 at which a marked decrease of oxygen concentration is detected by the binary ? sensor 26 to the time point T2 at which the marked increase of the oxygen concentration is detected by the reducing agent concentration sensor 25 under the NOx regeneration control.

Abstract: In an NOx purification system and a method for control of the NOx purification system, two oxidation catalysts are provided upstream of an ammonia solution supply unit, and the in-cylinder fuel injection is so controlled that hydrocarbon in exhaust gas is mainly oxidized by the upstream oxidation catalyst and nitric oxide in the exhaust gas is mainly oxidized by the downstream oxidation catalyst. In the purification of NOx in the exhaust gas by feeding an ammonia solution for NOx reduction to a selective reduction NOx catalyst, this technique enables the system to adjust the concentrations of HC, NO and NO2 in the exhaust gas flowing into the selective reduction NOx catalyst to proper values so as to purify the NOx efficiently by the selective reduction NOx catalyst. The NOx purification performance in a lower temperature range can be thus improved.

Abstract: In an exhaust gas purifying system which is equipped with an NOx occlusion reduction type catalyst (“NOx catalyst”) and an oxidation catalyst set on the upstream side of the NOx catalyst, and in which sulfur purge control for regenerating the sulfur-poisoned catalyst is conducted, an air fuel ratio control for sulfur purge is conducted when a temperature difference between an inlet side and an outlet side of the NOx catalyst is outside a given range. Sulfur poison on the NOx catalyst can be uniformly removed in sulfur-purge regeneration control, thereby extending the service life of the NOx catalyst. Further, the NOx catalyst can be protected from thermal deterioration caused by partial temperature rise inside the NOx catalyst on its downstream side, so that the service life of the NOx catalyst can also be extended.

Abstract: In regeneration control of an exhaust gas purification system (1) equipped with NOx occlusion reduction catalyst (11), a decision is made whether operating state of an engine is in a first engine operating range where the exhaust gas temperature is lower than a predetermined mode judgment temperature. If yes, EGR rich control is performed. Otherwise, injection rich control in exhaust pipe is performed. When EGR rich control is performed, a decision is made whether a vehicle is under acceleration or not. If a decision is made that the vehicle is under acceleration, regeneration control is postponed until that decision ends. This enables rich control for regeneration the NOx occlusion reduction catalyst (11), while avoiding deterioration in drivability (comfortableness) during acceleration of the vehicle.

Abstract: In an exhaust gas purification system (1) comprising a reducing agent supplying apparatus (17) and an exhaust gas purification apparatus (20) provided in that order from an upstream side of an exhaust passage (3) in an internal combustion engine (E), and a control unit for conducting reducing agent supply control, in which a reducing agent (F) for recovering purification capability of the exhaust gas purification apparatus (20) is supplied into an exhaust gas (G), in regenerating the exhaust gas purification apparatus (20), the concentration of the reducing agent in the exhaust gas (G), which flows into the exhaust gas purification apparatus (20), is varied temporally.

Abstract: The degree of a deterioration in catalyst is determined when the following requirements are satisfied: the operating state of an internal combustion engine (E) is in a predetermined operating state; and the temperature (T1m) of an exhaust gas, which flows into a catalyst (12), is in a second temperature range (?T80) in which the upper limit of the second temperature range (?T80) is 10% below the upper limit of a first temperature range (?T100) between the activation start temperature (Ta) and the activation end temperature (Tb) of the catalyst (12) before a deterioration and the lower limit of the second temperature range (?T80) is 10% above the lower limit of the first temperature range (?T100).

Abstract: In an exhaust gas purifying system (1) which is equipped with a NOx occlusion reduction type catalyst (11) and an oxidation catalyst (12) set on the upstream side of the catalyst (11) and in which sulfur purge control for regenerating the sulfur-poisoned catalyst (11) is conducted, in conducting the sulfur purge control, the air fuel ratio control for sulfur purge is conducted after the temperature difference (?TIO) between the inlet side and outlet side of the catalyst (11) has been reduced to a prescribed level (?T0) or below by raising the exhaust temperature. According to the invention, the sulfur poison on the catalyst (11) can be uniformly removed in the sulfur-purge regeneration control, whereby the service life of the catalyst (11) can be protected from being shortened by sulfur poisoning.

Abstract: An exhaust gas purification system (1) provided with an exhaust gas purification device (4), such as a NOx occlusion-reduction catalyst, in an exhaust passage (3) of an internal combustion engine (E), the exhaust gas purification device (4) purifying exhaust gas when the air-fuel ratio of exhaust gas in a lean state, and recovering purification ability when in a rich state. The system prevents highly dense, uncombusted fuel from acting as a binder that causes soot, together with the uncombusted fuel, to adhere to an EGR cooler (7) in an EGR passage (6) and thus clogging the EGR cooler (7). An uncombusted fuel adsorption device (20) for adsorbing uncombusted fuel is provided upstream to the EGR cooler (7) in the EGR passage (6), the uncombusted fuel adsorption device (20) adsorbing uncombusted fuel passing through the EGR passage (6) during a rich control.

Abstract: A method of controlling an NOx purification system (1), the system provided with an NOx occlusion reduction catalyst (22) and a control unit (30) that conducts NOx regeneration control and sulfur poisoning regeneration control. In the control method, the degree of deterioration of the NOx occlusion reduction catalyst (22) due to sulfur poisoning is estimated on the basis of the amount of the oxygen adsorbed and occluded at the NOx occlusion reduction catalyst (22) immediately after terminating the rich air-fuel state of the NOx regeneration control. In so doing, the amount of sulfur poisoning in the NOx occlusion reduction catalyst (22) is accurately estimated, and by performing sulfur poisoning regeneration at a suitable frequency, excessive sulfur poisoning regeneration can be avoided, thereby preventing the worsening of fuel consumption.

Abstract: In order to remove by burning captured PM by using microscopic luminescent discharge that repeats generation and extinction randomly in time and space on the surface of an insulating filter with a minimum power consumption and to enhance the capturing efficiency and combustion-removal efficiency of PM in exhaust gas from diesel engines or the like, at least one electrode pair (13) are arranged on or in the vicinity of the surface of an insulating capturing member (12) for capturing particulate matter (41) in exhaust gas, a predetermined voltage (Vs) is applied between the electrode pair (12) to generate a microscopic luminescent discharge (42) that repeats generation and extinction randomly in time and space on the surface of the insulating capturing member (12), and the microscopic luminescent discharge (42) generated by the application of this predetermined voltage (Vs) is used to remove by burning the particulate matter (41) captured on the insulating capturing member (12).

Abstract: An exhaust gas purification system has a NOx purification catalyst (22), and the catalyst (22) purifies exhaust gas of NOx when the air-fuel ratio of exhaust of an internal combustion engine (E) mounted on a vehicle is in a lean condition and recovers purification ability when the air-fuel ratio is in a rich condition. The system performs recovery control for setting the exhaust gas to a rich air-fuel condition in order to recover the NOx purification ability of the NOx purification catalyst (22), and at the time of retardation of the vehicle, both a fuel system rich control and an air intake rich control are used in the recovery control. The recovery control can be performed without worsening the drive comfort of the vehicle and with deterioration fuel of fuel consumption involved in the recovery control suppressed.

Abstract: An exhaust gas cleaning method capable of maintaining an optimum NOx purification ratio in the continuously regenerative range of DPF in an exhaust gas cleaning system (1) having an NOx purification function and a PM purification function combined with each other and the exhaust gas cleaning system (1). In the exhaust gas cleaning system (1), NOx purification by an NOx occlusion/reduction type catalyst (42) and PM purification by a continuous regeneration type DPF (41) are preformed for exhaust gas from an internal combustion engine.

Abstract: An exhaust gas decontamination system and a method of exhaust gas decontamination wherein in the regeneration of NOx occlusion reduction type catalyst with respect to a lean-burn engine or diesel engine, even in the instance of rich burning accompanied by EGR the NOx released from the NOx occlusion reduction type catalyst can satisfactorily be reduced and purged to thereby exhibit a high NOx removal ratio. The exhaust gas decontamination system (1) provided with the NOx occlusion reduction type catalyst (30) includes a control unit (C1) comprising a.norrnal control operation feature (C10), a regeneration control initiation judging feature (C20), a catalyst activation control-operation feature (C30) and a rich-burn control operation feature (C40) capable of lowering the concentration of oxygen in the exhaust gas so as to realize such a constitution that the catalyst is carried out just before rich burning accompanied by EGR.

Abstract: This invention provides a NOx purification system (1) having NOx occlusion reduction-type catalysts (2, 3) comprising an occlusion material and a metal catalyst, which occludes NOx in a lean state in terms of a fuel-air ratio of an exhaust gas and releases the occluded NOx in a rich state. In this system (1), a high-temperature type catalyst (2) is placed on the upstream side, and a low-temperature type catalyst (3) is disposed on the downstream side in series with the high-temperature type catalyst (2). The molar ratio of platinum to rhodium supported on the high-temperature type catalyst (2) is not less than 2:1 and not more than 1:2. According to the above construction, the NOx purification system (1) can have a wide NOx activation temperature window by devising the composition and layout of the catalyst.

Abstract: A guide structure for guiding exhaust gas flow to an exhaust gas sensor (55) in exhaust gas purification devices (50A to 50F) installed in an exhaust passage, wherein a plurality of exhaust gas purification units (52, 53) are disposed in series in the containers of the devices (50A to 50F), and the exhaust gas sensor (55) is installed between the exhaust gas purification units (52, 53). Thus, in the devices in which the plurality of exhaust gas purification units (52, 53) are disposed in series in the catalyst container installed in the exhaust passage, the responsibility of the exhaust gas sensor installed between the exhaust gas purification units (52, 53) can be increased.

Abstract: An exhaust gas purifying system causes less torque fluctuation and is capable of preventing the occurrence of white smoke in a regeneration control operation for regenerating a continuous regeneration DPF 3. When the continuous regeneration DPF 3 with an oxidation catalyst 3Aa on the upstream side of a filter 3Ab is controlled to regenerate, an exhaust throttle valve 31 provided in an exhaust passage 2 is closed and a delay multi-step injection control is performed to increase the temperature of the exhaust gas if an exhaust temperature T1 at the inlet of the oxidation catalyst 3Aa is less than the activation temperature Ta of the oxidation catalyst.

Abstract: A gas treatment device (1), comprising a charging agglomeration part (10) which charges and agglomerates components targeted for collection in gas by utilizing corona discharge, and a filter part (20) which collects the agglomerated components. The charging agglomeration part (10) is disposed on the upstream side, and the filter part (20) is disposed on the downstream side. By this configuration, using the agglomerating functions and precipitating functions of corona discharge and the precipitating functions of filters, ultra-fine particulates can be agglomerated and enlarged. Moreover, the present invention is a gas treatment device that has high performance and low pressure-loss and that is capable of being configured in a compact form factor such that it can also be used as an exhaust gas purification device mounted onboard an automobile.