Abstract: This invention is to reduce NOx occluded in a NOx catalyst in a more appropriate manner. In this invention, in case where an amount of NOx occluded when an execution condition for NOx reduction control holds is more than a predetermined amount of occlusion, NOx reduction control is performed by lowering the O2 concentration of the exhaust gas by means of said O2 concentration lowering means and at the same time supplying a reducing agent to the NOx catalyst by a reducing agent supplying means. In addition, in case where the amount of NOx occluded when the execution condition for NOx reduction control holds is equal to or less than the predetermined amount of occlusion, NOx reduction control is executed by supplying the reducing agent to the NOx catalyst by the reducing agent supplying means without lowering the O2 concentration of the exhaust gas by the O2 concentration lowering means.

Abstract: A technique is provided which is capable of completing SOx poisoning recovery control on a NOx storage reduction catalyst in a shorter period of time. In the course of the SOx poisoning recovery control, the degree of decrease of a SOx release speed resulting from a decrease in an amount of SOx occlusion of the NOx catalyst (the degree of decrease of the SOx release speed (Ddw)) with respect to that at the time of start of the SOx poisoning recovery control is estimated. In accordance with the increasing degree of decrease of the SOx release speed (Ddw), a catalyst bed temperature (Tc) is caused to rise up to a higher side target temperature (Tct), and at the same time an exhaust gas air fuel ratio (A/F) is caused to lower up to a richer side target air fuel ratio (A/Ft), whereby the SOx release speed Vsox during the SOx poisoning recovery control is suppressed from lowering.

Abstract: An object of the invention is to recover the capability of an exhaust gas purification apparatus provided in an exhaust passage of an internal combustion engine with improved reliability. According to the invention there are provided recovery control execution unit for executing a recovery control in which the temperature of the exhaust gas purification apparatus is raised by supply of reducing agent to a precatalyst to thereby recover the capability of the exhaust gas purification apparatus and prohibition range setting unit for setting a recovery control prohibition range that is an operation range of the internal combustion engine in which execution of the recovery control by the recovery control execution unit is prohibited. The higher the degree of deterioration of the precatalyst is, the higher the maximum values of the engine torque and the engine revolution number in the recovery control prohibition range are set to be.

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, an NOX selective reducing catalyst (15) is arranged in an engine exhaust passage. Aqueous urea is fed from an aqueous urea feed valve (17) into the NOX selective reducing catalyst (15) to selectively reduce the NOX contained in the exhaust gas with the ammonia generated from the aqueous urea. The moisture contained in the exhaust gas is recovered and stored in a water tank (21). It is provided with a high concentration aqueous urea tank (22) storing high concentration aqueous urea having a higher urea concentration than the urea concentration of the aqueous urea fed to the NOX selective reducing catalyst (15), and the high concentration aqueous urea is diluted with the recovered moisture thereby generating aqueous urea fed to the NOX selective reducing catalyst (15).

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: 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 internal combustion engine in an engine exhaust passage of which an NOx adsorption catalyst (12) adsorbing NOx contained in exhaust gas at the time of a low temperature and desorbing the adsorbed NOx when the temperature rises and an NOx storage catalyst (14) are arranged. When the NOx storage catalyst (14) can store NOx, the temperature of the NOx adsorption catalyst (12) is made to forcibly rise to a target temperature at which the amount of NOx which the NOx storage catalyst (14) can store is desorbed, and the NOx desorbed from the NOx adsorption catalyst (12) is stored in the NOx storage catalyst (14).

Abstract: This invention is to reduce NOx occluded in a NOx catalyst in a more appropriate manner. In this invention, in case where an amount of NOx occluded when an execution condition for NOx reduction control holds is more than a predetermined amount of occlusion, NOx reduction control is performed by lowering the O2 concentration of the exhaust gas by means of said O2 concentration lowering means and at the same time supplying a reducing agent to the NOx catalyst by a reducing agent supplying means. In addition, in case where the amount of NOx occluded when the execution condition for NOx reduction control holds is equal to or less than the predetermined amount of occlusion, NOx reduction control is executed by supplying the reducing agent to the NOx catalyst by the reducing agent supplying means without lowering the O2 concentration of the exhaust gas by the O2 concentration lowering means.

Abstract: A technique is provided which is capable of completing SOx poisoning recovery control on a NOx storage reduction catalyst in a shorter period of time. In the course of the SOx poisoning recovery control, the degree of decrease of a SOx release speed resulting from a decrease in an amount of SOx occlusion of the NOx catalyst (the degree of decrease of the SOx release speed (Ddw)) with respect to that at the time of start of the SOx poisoning recovery control is estimated. In accordance with the increasing degree of decrease of the SOx release speed (Ddw), a catalyst bed temperature (Tc) is caused to rise up to a higher side target temperature (Tct), and at the same time an exhaust gas air fuel ratio (A/F) is caused to lower up to a richer side target air fuel ratio (A/Ft), whereby the SOx release speed Vsox during the SOx poisoning recovery control is suppressed from lowering.

Abstract: An object of the invention is to recover the capability of an exhaust gas purification apparatus provided in an exhaust passage of an internal combustion engine with improved reliability. According to the invention there are provided recovery control execution unit for executing a recovery control in which the temperature of the exhaust gas purification apparatus is raised by supply of reducing agent to a precatalyst to thereby recover the capability of the exhaust gas purification apparatus and prohibition range setting unit for setting a recovery control prohibition range that is an operation range of the internal combustion engine in which execution of the recovery control by the recovery control execution unit is prohibited. The higher the degree of deterioration of the precatalyst is, the higher the maximum values of the engine torque and the engine revolution number in the recovery control prohibition range are set to be.

Abstract: In an internal combustion engine, an NOX selective reducing catalyst (15) is arranged in an engine exhaust passage. Aqueous urea is fed from an aqueous urea feed valve (17) into the NOX selective reducing catalyst (15) to selectively reduce the NOX contained in the exhaust gas with the ammonia generated from the aqueous urea. The moisture contained in the exhaust gas is recovered and stored in a water tank (21). It is provided with a high concentration aqueous urea tank (22) storing high concentration aqueous urea having a higher urea concentration than the urea concentration of the aqueous urea fed to the NOX selective reducing catalyst (15), and the high concentration aqueous urea is diluted with the recovered moisture thereby generating aqueous urea fed to the NOX selective reducing catalyst (15).

Abstract: The present invention is to provide a technique which can detect the level of degradation of a precatalyst in an exhaust gas purification system for an internal combustion engine that includes a NOx catalyst arranged on an exhaust passage of the internal combustion engine, and the precatalyst arranged on the exhaust passage at a location upstream of the NOx catalyst and having an oxidation function. In the present invention, the level of degradation of the precatalyst is detected based on the width of change in temperature of the NOx catalyst at the time when a reducing agent is intermittently supplied from an upstream side of the precatalyst to the precatalyst and the NOx catalyst. At this time, it is determined that the larger the width of change in temperature of the NOx catalyst, the higher the level of degradation of the oxidation catalyst is.

Abstract: A NOx absorbent is arranged in an exhaust passage of an internal combustion engine, and a fuel supply valve (28) is arranged in the exhaust passage upstream of the NOx absorbent. If the temperature of the NOx absorbent is lower than a predetermined temperature when the NOx must be released from the NOx absorbent, the air-fuel ratio of exhaust gas flowing through the NOx absorbent is first switched from a basic lean air-fuel ratio to and maintained at a lean air-fuel ratio with a lower leanness for a predetermined lean time, and is then switched to a rich air-fuel ratio. If the temperature of the NOx absorbent is higher than the predetermined temperature when the NOx must be released from the NOx absorbent, the air-fuel ratio of the exhaust gas flowing through the NOx absorbent is switched to the rich air-fuel ratio without being switched to the lean air-fuel ratio with a lower leanness.

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 purification catalyst for a compression ignition engine comprises a carrier substrate and a metal-carrying layer which carries catalytic metal formed on the surface of the carrier substrate, and is characterized in that a diffusion restriction layer having a thickness smaller than 170 &mgr;m is provided on the surface of the metal-carrying layer opposite to the

Abstract: An exhaust temperature raising apparatus has an exhaust throttle valve that adjusts the engine exhaust amount based on the amount of throttling, and an injector that performs main injection and a sub-injection directly into a cylinder, a combination of an ECU, the injection and the exhaust throttle valve as exhaust gas temperature increase apparatus for, during an engine warm-up, performing and controlling the exhaust throttling by the exhaust valve and performing and controlling an exhaust gas temperature increase through combustion attributed to the main injection performed in an excess-air condition and combustion attributed to the sub-injection, an exhaust gas temperature sensor that monitors a state of temperature increase of the exhaust gas caused by performance of the exhaust gas temperature increase apparatus, and the ECU as monitor abnormality detection apparatus for determining whether the exhaust gas temperature sensor has an abnormality, and the ECU as exhaust gas temperature increase stop apparat

Abstract: An exhaust purification catalyst for a compression ignition engine comprises a carrier substrate and a metal-carrying layer which carries catalytic metal formed on the surface of the carrier substrate, and is characterized in that a diffusion restriction layer having a thickness smaller than 170 &mgr;m is provided on the surface of the metal-carrying layer opposite to the carrier substrate.

Abstract: According to the present invention, there is provided an exhaust gas purification device, comprising a NOx absorbent arranged in an exhaust passage of an engine for absorbing NOx therein when an air-fuel ratio of an exhaust gas flowing into the NOx absorbent is lean, the NOx absorbent discharging NOx absorbed therein when a concentration of the oxygen in the exhaust gas flowing into the NOx absorbent decreases, a trapping element arranged in the exhaust passage upstream of the NOx absorbent for trapping particulates, a processing element for processing the particulates trapped in the trapping element to regenerate the trapping element, and a preventing element for preventing the exhaust gas from flowing into the NOx absorbent from the trapping element when the trapping element is regenerated.

Abstract: In an exhaust gas purification device, a catalytic converter containing selective reduction catalysts is disposed in an exhaust gas passage of an internal combustion engine capable of being operated at a lean air-fuel ratio. The catalytic converter includes a plurality of the selective reduction catalysts disposed in series in the casing of the catalytic converter. Bypass passages which supply the exhaust gas to downstream selective reduction catalysts in the casing by bypassing the upstream catalysts are provided. When a reducing agent is supplied to the exhaust gas upstream of the converter, a part of the supplied reducing agent directly reaches the downstream selective reduction catalyst through the bypass passages without being oxidized by the upstream selective reduction catalysts. Therefore, the NOx purifying abilities of the downstream catalysts are improved and the formation of sulfates on the downstream catalysts is suppressed.