Abstract: An exhaust emission control device is disclosed. The device includes an NOx-occlusion reduction catalyst incorporated in an exhaust passage for reduction and purification of NOx, a fuel reforming catalyst structure and plasma fuel reforming unit for decomposition of the fuel into H2 and CO is arranged in the exhaust passage upstream of the reduction catalyst, so that the fuel is decomposed into H2 and CO such that NOx on the surface of the NOx-occlusion reduction catalyst can be efficiently reduced into N2. Thus, high NOx reduction ratio can be always obtained irrespective of variety of operational conditions.

Abstract: Excessive generation NO2 by oxidation catalyst arrangement upstream of a selective reduction catalyst is suppressed to prevent falling of NOx reduction rate. A selective reduction catalyst 4 capable of selectively reacting NOx with ammonia even in the presence of oxygen is incorporated in an exhaust pipe 3 from an engine 1. A pair of oxidation catalysts 5A and 5B are arranged in parallel with each other and upstream of the selective reduction catalyst. In an operation condition with low exhaust temperature, amounts of the exhaust gas 2 distributed to the oxidation catalysts 5A and 5B are adjusted so as to make NO/NO2 ratio in the exhaust gas 2 to about 1-1.5.

Abstract: In an exhaust emission control device with NOx-occlusion reduction catalyst 5 incorporated in an exhaust passage 2,4 for reduction and purification of NOx, a fuel reforming catalyst structure 7 or plasma fuel reforming means 8 for decomposition of the fuel into H2 and CO is arranged in the exhaust passage 2,4 upstream of the reduction catalyst 5, so that the fuel is decomposed into and CO. By such H2 and CO, NOx on the surface of the NOx-occlusion reduction catalyst can be efficiently reduced into N2. Thus, high NOx reduction ratio can be always obtained irrespective of variety of operational conditions.

Abstract: An exhaust emission control device is provided which can effectively regenerate a NOx absorption reduction catalyst even in a relatively low temperature region to improve NOx reduction ratio while minimizing deterioration of fuel economy. Incorporated in an exhaust pipe 4 through which exhaust gas 3 discharged from a diesel engine 1 via an exhaust manifold 2 flows is a reformer 8 having a fuel adding device 5, a heater 6 and a reforming catalyst 7. Arranged downstream of the reformer is a NOx absorption reduction catalyst 9.

Abstract: Arranged within a cylindrical housing are capturing cells each including a cylindrical outer electrode capable of capturing particulates and an inner electrode inserted into the outer electrode and lined at its outer surface with a dielectric. A divergent exhaust unit is arranged on an end of the housing so as to guide exhaust to interiors in the respective capturing cells. A convergent exhaust unit is arranged on the other end of the housing so as to communicate with a gap between an inner surface of the housing and outer surfaces of the outer electrodes in the respective cells. The inner and outer electrodes are connected to an electric discharge controller.

Abstract: An exhaust emission control device with a plasma generator received in a filter casing incorporated in an exhaust pipe for capturing particulates and capable of conducting electric discharge so as to generate plasma in the exhaust gas at a capturing place and with a power supply for impressing voltage on the plasma generator. The plasma generator is unitized and arranged in plurality. A control switch is provided for sequential changeover of the connection of the power supply to the plural units of the plasma generator. A processing capability comparable to a single, large-sized plasma generator is obtained while increase in size of the power supply is prevented.

Abstract: Excessive generation NO2 by oxidation catalyst arrangement upstream of a selective reduction catalyst is suppressed to prevent falling of NOx reduction rate. A selective reduction catalyst 4 capable of selectively reacting NOx with ammonia even in the presence of oxygen is incorporated in an exhaust pipe 3 from an engine 1. A pair of oxidation catalysts 5A and 5B are arranged in parallel with each other and upstream of the selective reduction catalyst. In an operation condition with low exhaust temperature, amounts of the exhaust gas 2 distributed to the oxidation catalysts 5A and 5B are adjusted so as to make NO/NO2 ratio in the exhaust gas 2 to about 1-1.5.

Abstract: Arranged within a cylindrical housing 1 are capturing cells 2 each including a cylindrical outer electrode 7 capable of capturing particulates and an inner electrode 6 inserted into the outer electrode and lined at its outer surface with a dielectric 5. Exhaust divergent means 3 is arrange on an end of the housing 1 so as to guide exhaust G to interiors in the respective capturing cells 2; exhaust convergence means 4 is arranged on the other end of the housing 1 so as to communicate with a gap 14 between an inner surface of the housing and outer surfaces of the outer electrodes 7 in the respective cells 2. The inner and outer electrodes 6 and 7 are connected to an electric discharge controller 15. Thus, provided is an exhaust emission control device with high removal efficiency of particulates and with easiness in maintenance.

Abstract: An exhaust emission control device with less electricity consumption comprises a cylindrical outer electrode 7 extending in a direction of flow of exhaust G, a plurality of inner electrodes 5 and 6 constituted by electrically conductive filters capable of capturing particulates and aligned in the direction of flow of the exhaust G within an outer electrode 7, captured particulate amount estimating means 2 for estimating captured particulate amounts of the respective inner electrodes 5 and 6 and an electric discharge controller 3 for supplying electric power for generation of electric discharge to the outer electrode 7 and any of the inner electrodes 5 and 6 on the basis of calculated values of the estimating means 2.