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: Carbon-containing particulates like soot included in an exhaust gas of an internal combustion engine are collected by means of a heat-resistant filter medium. The filter medium dispersedly collects hydrocarbon compounds and the carbon-containing particulates included in the exhaust gas. Even when the exhaust gas has a lower temperature than the combustible temperature of the carbon-containing particulates, such dispersed collection ensures start of a preliminary oxidation reaction of the collected hydrocarbon compounds with oxygen included in the exhaust gas. The collected hydrocarbon compounds and the collected carbon-containing particulates are then subjected to combustion with the exhaust gas having a filter inflow temperature lower than the combustible temperature of the carbon-containing particulates by utilizing the reaction heat and active species produced by the reaction. This technique thus simply but securely regulates and reduces the carbon-containing particulates included in the exhaust gas.

Abstract: Exhaust emission control apparatus and method for an internal combustion engine maintain a small amount of sulfur components contained in exhaust gas flowing out of a sulfur component retainer agent even if the amount of sulfur components retained by the agent becomes great. The exhaust emission control apparatus includes a NOx retainer agent and the sulfur component retainer agent. The apparatus performs a NOx releasing process of adjusting the air-fuel ratio of exhaust gas flowing into the sulfur component retainer agent so that the air-fuel ratio of exhaust gas flowing into the NOx retainer agent becomes substantially stoichiometric or rich of stoichiometry if NOx retained by the NOx retainer agent is to be released. The apparatus prohibits the air-fuel ratio of exhaust gas flowing into the sulfur component retainer agent from becoming substantially stoichiometric or rich of stoichiometry if the amount of the sulfur components retained by the agent is at least a first predetermined amount.

Abstract: A device for purifying the exhaust gas of an internal combustion engine includes a particulate filter carrying an active-oxygen releasing agent that can cause the sulfur poisoning, a SOx trap unit arranged upstream of the particulate filter, and a bypass section for making the exhaust gas mainly bypass said particulate filter when SOx is released from the SOx trap unit. Further, an exhaust choke valve for an exhaust brake is arranged between the SOx trap unit and the exhaust gas branch portion of the bypass section.

Abstract: A first heat-resistant filter medium is disposed in an exhaust pathway of an internal combustion engine. The first heat-resistant filter medium traps hydrocarbon compounds and carbon-containing particulates included in a flow of exhaust gas in a dispersive manner to bring the respective particulates and hydrocarbon compounds in contact with oxygen included in the exhaust gas. The trapped hydrocarbon compounds and the trapped carbon-containing particulates are subjected to combustion with the exhaust gas having a filter inflow temperature lower than a combustible temperature of the carbon-containing particulates. A second heat-resistant filter medium is further disposed downstream of the first heat-resistant filter medium to trap the remaining carbon-containing particulates, which have not been trapped by the first heat-resistant filter medium but have passed through the first heat-resistant filter medium. This arrangement desirably enhances the reduction rate of the particulates.

Abstract: Exhaust emission control apparatus and method for an internal combustion engine maintain a small amount of sulfur components contained in exhaust gas flowing out of a sulfur component retainer agent even if the amount of sulfur components retained by the agent becomes great. The exhaust emission control apparatus includes a NOx retainer agent and the sulfur component retainer agent. The apparatus performs a NOx releasing process of adjusting the air-fuel ratio of exhaust gas flowing into the sulfur component retainer agent so that the air-fuel ratio of exhaust gas flowing into the NOx retainer agent becomes substantially stoichiometric or rich of stoichiometry if NOx retained by the NOx retainer agent is to be released. The apparatus prohibits the air-fuel ratio of exhaust gas flowing into the sulfur component retainer agent from becoming substantially stoichiometric or rich of stoichiometry if the amount of the sulfur components retained by the agent is at least a first predetermined amount.

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: A device for purifying the exhaust gas of an internal combustion engine is disclosed. The device comprises a particulate filter carrying an active-oxygen releasing agent that can cause the sulfur poisoning, a SOx trap unit arranged upstream of the particulate filter, and a bypass means for making the exhaust gas mainly bypass said particulate filter when SOx is released from the SOx trap unit. Further, an exhaust choke valve for an exhaust brake is arranged between the SOx trap unit and the exhaust gas branch portion of the bypass means.

Abstract: A first heat-resistant filter medium is disposed in an exhaust pathway of an internal combustion engine. The first heat-resistant filter medium traps hydrocarbon compounds and carbon-containing particulates included in a flow of exhaust gas in a dispersive manner to bring the respective particulates and hydrocarbon compounds in contact with oxygen included in the exhaust gas. The trapped hydrocarbon compounds and the trapped carbon-containing particulates are subjected to combustion with the exhaust gas having a filter inflow temperature lower than a combustible temperature of the carbon-containing particulates. A second heat-resistant filter medium is further disposed downstream of the first heat-resistant filter medium to trap the remaining carbon-containing particulates, which have not been trapped by the first heat-resistant filter medium but have passed through the first heat-resistant filter medium. This arrangement desirably enhances the reduction rate of the particulates.

Abstract: Carbon-containing particulates like soot included in an exhaust gas of an internal combustion engine are collected by means of a heat-resistant filter medium. The filter medium dispersedly collects hydrocarbon compounds and the carbon-containing particulates included in the exhaust gas. Even when the exhaust gas has a lower temperature than the combustible temperature of the carbon-containing particulates, such dispersed collection ensures start of a preliminary oxidation reaction of the collected hydrocarbon compounds with oxygen included in the exhaust gas. The collected hydrocarbon compounds and the collected carbon-containing particulates are then subjected to combustion with the exhaust gas having a filter inflow temperature lower than the combustible temperature of the carbon-containing particulates by utilizing the reaction heat and active species produced by the reaction. This technique thus simply but securely regulates and reduces the carbon-containing particulates included in the exhaust gas.

Abstract: A device for purifying the exhaust gas of an internal combustion engine is disclosed. The device comprises a collision collecting type filter for collecting particulates which is arranged in an exhaust passage, can vary a pressure in the exhaust passage on at least one of the upstream side and downstream side of said filter, determines that the collected particulates have been burned and the filter has been regenerated, and suddenly changes the pressure in the exhaust passage when it is determined that the filter has been regenerated.