An exhaust after-treatment system for treating an exhaust produced by an engine. The exhaust after-treatment system includes an exhaust passage, at least one catalytic exhaust after-treatment component in communication with the exhaust passage for treating the exhaust, and a water-removal device in communication with the exhaust passage that receives a portion of the exhaust therein at a location positioned upstream from the catalytic exhaust after-treatment component. The water-removal device is defined by a housing that includes a water-removal membrane that separates water from the portion of the exhaust to provide a permeate that is enriched with water, and to produce a retentate that is water depleted that facilitates the treating of the exhaust by the catalytic exhaust after-treatment component.

A high-end processing device for purification of exhaust of a diesel engine includes a connection channel, a plurality of catalytic converters, a plurality of direct-passage ceramic filters, and at least one wall-flow filter. The catalytic converters are arranged, in a manner of being spaced from each other, at a front portion of an exhaust gas flow path defined by the connection channel. The direct-passage ceramic filters and the wall-flow filter are arranged, in a manner of being spaced from each other, at a rear portion of the exhaust gas flow path of the connection channel. The direct-passage ceramic filters and the wall-flow filter are impregnated with urea or ammonia and dried so as to reduce nitrogen oxides (NOx) into nitrogen and water to reduce impact to the environment.

An exhaust-gas purification system and method are provided for an internal combustion engine having an NOx storage catalytic converter and a downstream SCR catalytic converter. The NOx storage catalytic converter can be supplied in a first operating mode with an oxidizing exhaust gas and in a second operating mode with a reducing exhaust gas. A third operating mode is provided between the first operating mode and the second operating mode, in which an exhaust gas which has a lower content of oxidizing constituents than the first operating mode and a lower content of reducing constituents than the second operating mode can be supplied to the NOx storage catalytic converter to improve NH.sub.3 production at the start of converter regeneration.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, a first treatment element positioned within the exhaust gas pathway, a first injector configured to introduce a first reductant into the exhaust gas pathway upstream of the first treatment element, a second injector configured to introduce a second reductant into the exhaust gas pathway downstream of the first treatment element, a second treatment element positioned within the exhaust gas pathway downstream of the second injector, the second treatment element including a SCR element, and a controller configured to periodically initiate a desulfuring regeneration cycle by increasing a concentration of hydrocarbons in the exhaust gas and increasing the flow of the first reductant through the first injector to oxidize sulfur contamination in the first treatment element at temperatures between 400 and 500 degrees Celsius.

Methods and systems are provided for a resonator of an exhaust system. In one example, the resonator is a quarter wave resonator with a diaphragm configured to provide pulsations during low-end engine torque conditions.

Methods and systems for operating an engine that includes a catalyst and a particulate filter are described. In one example, release of reductant from an injector may be determined according to a plurality of metrics so that reliability of a release indication may be improved. In addition, operation of an engine may be adjusted responsive to the release indication so that exhaust system temperatures may be maintained.

An under-floor catalyst (33) includes a GPF (41) capable of trapping fine exhaust particles in exhaust gas, and a downstream-side catalyst (42) positioned on the downstream side of GPF (41). GPF (41) can be supplied with secondary air. When an internal combustion engine (10) is stopped during travel, the secondary air is supplied to GPF (41) in which the fine exhaust particles are accumulated. At this time, the temperature of GPF (41) is equal to or higher than a predetermined temperature. Thus, a deterioration in the exhaust gas purification performance of under-floor catalyst (33) at the time of the start of internal combustion engine (10) can be suppressed.

An exhaust gas aftertreatment system includes: a first sensor configured to measure a parameter in the exhaust gas aftertreatment system; a second sensor configured to measure the parameter in the exhaust gas aftertreatment system, the second sensor disposed proximate the first sensor; and at least one controller configured to simultaneously receive sensor values from the first sensor and receive sensor values from the second sensor.

The invention relates to an exhaust aftertreatment arrangement (100) for an exhaust system of an internal combustion engine, said exhaust aftertreatment arrangement (100) comprising a fluid passage (30) for exhaust gases from said exhaust system, said fluid passage (30) defining an inner perimeter (32) and an exhaust aftertreatment unit (40) comprising an exhaust aftertreatment element (42) confined by an outer wall (44) defining an outer periphery (46) of the exhaust aftertreatment unit (40), the exhaust aftertreatment unit (40) being sealingly arranged in said fluid passage (30) for enabling flow of said exhaust gases through said exhaust aftertreatment element (42). A leakage treatment member (50) comprising an exhaust aftertreatment component is arranged between said inner perimeter (32) of the fluid passage (30) and said outer periphery (46) of said outer wall (44) of the exhaust aftertreatment unit (40), for aftertreatment of any leakage of said flow of exhaust gases past said aftertreatment unit (40) in said fluid passage (30).

A diagnostic system for an internal combustion engine is disclosed. The diagnostic system may include an electronic control unit. The electronic control unit may determine whether a predetermined condition is satisfied. The predetermined condition may be a condition under which an amount of particulate matter that separates from a filter is larger than or equal to a predetermined separation amount as a urea water-originated deposit once accumulated in the filter separates in gaseous form. When the electronic control unit determines that the predetermined condition is satisfied, the electronic control unit may not execute a diagnosis of a malfunction in the filter based on a filter differential pressure until a predetermined period elapses from the point in time at which it is determined that the predetermined condition is satisfied.