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 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: A catalyst suited for reducing NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in an engine exhaust passage. An aqueous urea solution is fed from a flow addition valve onto a catalyst, part of the urea fed to the catalyst is stored in the catalyst, and the ammonia generated from the urea stored in the catalyst is used to reduce the NOx in the exhaust gas. At the time of engine startup, at the time of cold operation, and at the time of increase of the HC amount, it is determined that the amount of formaldehyde in the exhaust gas flowing into the catalyst exceeds the allowable amount, and, at this time, the feed of urea to the catalyst is prohibited.

Abstract: A device for purifying the exhaust gas of an internal combustion engine is disclosed. The device includes a particulate filter arranged in the exhaust system, which carries a catalyst for absorbing and reducing NOx. The catalyst absorbs NOx when the air-fuel ratio in the surrounding atmosphere thereof is lean and releases the absorbed NOx to purify NOx by reduction when the air-fuel ratio is stoichiometric or rich. The device further includes a catalytic apparatus for purifying NOx arranged in the exhaust system upstream of the particulate filter, which has an oxidation function.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: This invention relates to an exhaust gas purifying apparatus having a particulate filter for collecting particulates in exhaust gas. This particulate filter (22) contains partition walls defining paths (50, 51) in which exhaust gas flows. This partition wall is formed of porous material. This particulate filter (22) is created by gathering tips of the partition walls and then baking with the adjacent partition walls being in contact with each other. The adjacent partition walls are bonded together at a predetermined bonding strength if the partition walls are baked such that they are in contact. According to this invention, the end portion of the particulate filter (22) has a higher strength than the predetermined bonding strength.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: An exhaust gas purification apparatus for an engine having a combustion chamber includes a device that prevents overheating of a particulate filter. The apparatus includes an exhaust passage, a particulate filter arranged in the exhaust passage for removing particulate in exhaust gas exhausted from the combustion chamber by oxidation, and a device for controlling the characteristics of the exhaust gas flowing into the particulate filter. A judgment is made whether the particulate filter will be deteriorated by heat. If yes, the controlling device changes the characteristics of the exhaust gas flowing into the particulate filter to prevent the particulate filter from being deteriorated by heat.

Abstract: An exhaust emission purification device comprises a sulfur component holding agent arranged on the exhaust path of an internal combustion engine for holding a sulfur component, a NOx holding agent arranged downstream of the sulfur component holding agent in the exhaust gas for holding NOx and the sulfur components when the air-fuel ratio of the exhaust gas flowing thereinto is lean, and a reducing agent adding unit for adding a reducing agent to the exhaust gas flowing into the NOx holding agent. The concentration of the sulfur component contained in the reducing agent added by the reducing agent adding unit is lower than the concentration of at least the sulfur component contained in the fuel supplied to the combustion chamber of the internal combustion engine. Thus, the sulfur poisoning of the exhaust emission purifier can be avoided while at the same time reducing the fuel consumption rate.

Abstract: Disclosed is an input/output coupling structure for a dielectric waveguide resonator to be mounted on a printed circuit board, which comprises; a region defined in the printed circuit board and surrounded by a first conductive film formed on the front surface of the printed circuit board and connected to a microstrip line on the printed circuit board, a second conductive film formed on the back surface of the printed circuit board, and a conductive wall connecting the respective peripheries of the first and second conductive films; a first slot formed in the front surface of the region; and a second slot formed in a surface of the dielectric waveguide resonator which is disposed to be opposed to the region of the printed circuit board. The first and second slots are adapted to be disposed in opposed relation to one another.

Abstract: A method of fabricating a substrate used for purifying an exhaust gas is provided. This method comprises the step of transforming a pre-mold having a first end, a second end, a plurality of partition walls extending between the first end and the second end, the first transforming step for transforming the end portions of the partition walls at the first end in such a manner that the ends of the partition walls defining one of two adjacent passages at the first end of the pre-mold are collected toward the center of a corresponding passage and connected to each other, and the second transforming step for transforming the ends of the partition walls at the first end in such a manner that the end surfaces of the partition walls at the first end are depressed toward the center of each of the end surfaces.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, wherein the efficiency of exhaust gas purification is enhanced by optimally controlling the operating condition of a plasma generator mounted in an exhaust passage in accordance with the exhaust gas atmosphere. The exhaust gas purifying apparatus includes a detection unit for detecting exhaust water content and exhaust temperature; and a control unit for controlling at least one of two factors, frequency or voltage of an AC voltage used to operate the plasma generator mounted in the exhaust passage, in accordance with the detected exhaust water content and exhaust temperature.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: A catalyst (22) suitable for reduction of the NOxin an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.

Abstract: A catalyst (22) suitable for reduction of the NOx in an exhaust gas by ammonia in the presence of excess oxygen is arranged in the exhaust passage (18, 21) of an internal combustion engine. An aqueous urea solution is fed through a flow control valve (33) to the inside of the exhaust passage (21) upstream of the catalyst (22). When the temperature of the catalyst (22) is low, a large amount of the aqueous urea solution is fed to make the urea contained in the aqueous urea solution be stored in the catalyst (22). When the engine is accelerated and the temperature of the catalyst (22) rises, ammonia is released at a little at a time from the inside of the catalyst (22) and the NOx in the exhaust gas is reduced by the released ammonia.