An exhaust treatment system comprising a first oxidation catalyst to oxidize nitrogen and/or carbon compounds in an exhaust stream and a first dosage device downstream of said first oxidation catalyst to supply a first additive. A first reduction catalyst device is arranged downstream of said first dosage device for reduction of nitrogen oxides using said first additive, and for the generation of heat, through at least one exothermal reaction with said exhaust stream. A particulate filter arranged downstream of said first reduction catalyst device to catch soot particles and a second dosage device, arranged downstream of said particulate filter to supply a second additive. A second reduction catalyst device is arranged downstream of said second dosage device for reduction of nitrogen oxides in said exhaust stream, through the use of at least one of said first and said second additive.

A method and an exhaust treatment system are provided for treatment of an exhaust stream that comprises nitrogen oxides NO.sub.x. The method comprises using a first slip-catalyst SC.sub.1, arranged at a first device to create a first impact on a first amount of nitrogen oxides NO.sub.x.sub._.sub.1 An NO.sub.x-storing catalyst may store nitrogen oxides NO.sub.x. The first slip-catalyst SC.sub.1 may reduce nitrogen oxides NO.sub.x, and/or oxidize potential additive in the exhaust stream. This first impact is actively controlled, based on the first amount of nitrogen oxides NO.sub.x.sub._.sub.1 reaching the first device. The method also comprises a second impact on a second amount of nitrogen oxides NO.sub.x.sub._.sub.2 reaching a second device. The active control of the first impact may be by active control of the dosage of additive at the first device, and/or through an active control of an exhaust environment, for example, a temperature for the exhaust stream.

An exhaust treatment system is provided for treatment of an exhaust stream, where the system comprises a first dosage device, arranged to supply a first additive into said exhaust stream and a first reduction catalyst device, arranged downstream for reduction of nitrogen oxides in said exhaust stream through the use of said first additive, and for the generation of heat through at least one exothermal reaction with said exhaust stream. A particulate filter arranged downstream of said first reduction catalyst device to catch soot particles. A second dosage device arranged downstream of said particulate filter to supply a second additive into said exhaust stream and a second reduction catalyst device, arranged downstream of said second dosage device for reduction of nitrogen oxides in said exhaust stream through the use of at least one of said first and said second additive.

A treatment system for providing treatment of an exhaust stream comprising nitrogen oxides NO.sub.x, in which nitrogen monoxide NO and nitrogen dioxide NO.sub.2 are comprised. When the exhaust stream passes through the treatment system, oxidation occurs of compounds comprising nitrogen, carbon and/or hydrogen. An amount of nitrogen oxides NO.sub.x reaching a reduction catalyst device downstream of the oxidizing component in the exhaust treatment system is reduced. A ratio (NO.sub.2/NO.sub.x).sub.det between an amount of nitrogen dioxide NO.sub.2 reaching a reduction catalyst device and the amount of nitrogen oxides NO.sub.x reaching the reduction catalyst device is determined. An active control of at least one parameter related to the combustion engine is carried out, based on the determined ratio, so that the amount of nitrogen oxides NO.sub.x reaching the reduction catalyst device is increased, if the determined ratio (NO.sub.2/NO.sub.x).sub.det exceeds an upper threshold value (NO.sub.2/NO.sub.x).sub.threshold.sub._.sub.high.

An exhaust treatment system comprising: a first dosage device, arranged to supply a first additive into said exhaust stream; a first reduction catalyst device, downstream of said first dosage device arranged for reduction of nitrogen oxides in said exhaust stream through the use of said first additive; a particulate filter, at least partly comprising a catalytically oxidizing coating, which is downstream of said first reduction catalyst device to catch soot particles, and to oxidize one or several of nitrogen oxide and incompletely oxidized carbon compounds in said exhaust stream; a second dosage device, downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device, downstream of said second dosage device for a reduction of nitrogen oxides in said exhaust stream, with the use of at least one of said first and said second additive.

A particulate matter detection apparatus is provided with an element portion onto which PM contained in exhaust gas of an engine adheres thereto. A heater which heats the element portion, a quantity detecting portion which detects a quantity of the PM based on electrical properties of the element portion and a temperature detecting portion which detects a temperature of the element portion. The apparatus is further provided with a first and second temperature controller. The first temperature controller heats the element portion using a heater in a first period, which excludes a period in which PM adheres to the element portion based on a detected temperature of the element portion. The element portion is heated in a first temperature range to combust soluble organic fractions contained in the PM and resist melting of ash components contained in the PM. The first period excludes a period in which PM adheres to the element portion. The second temperature controller heats the element portion in the second temperature range, which is higher than the first temperature range using the heater, such that ash is combusted, based on a detected temperature of the element portion.

An exhaust treatment system comprising: a first dosage device, arranged to supply a first additive into said exhaust stream; a first reduction catalyst device, downstream of said first dosage device arranged for reduction of nitrogen oxides in said exhaust stream through the use of said first additive; a particulate filter, at least partly comprising a catalytically oxidizing coating, which is downstream of said first reduction catalyst device to catch soot particles, and to oxidize one or several of nitrogen oxide and incompletely oxidized carbon compounds in said exhaust stream; a second dosage device, downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device, downstream of said second dosage device for a reduction of nitrogen oxides in said exhaust stream, with the use of at least one of said first and said second additive.

An after-treatment system including an exhaust treatment component provided in an exhaust passage, a tank carrying an aqueous reagent, and an electrochemical cell in communication with the tank and configured to receive the aqueous reagent therefrom. The electrochemical cell is configured to convert the aqueous reagent into a first exhaust treatment fluid and a second exhaust treatment fluid. A controller is in communication with the electrochemical cell. The controller is configured to vary amounts and/or composition of each of the first exhaust treatment fluid and the second exhaust treatment fluid produced by the electrochemical cell. An injector is in communication with the electrochemical cell and the exhaust passage, and is configured to receive one of the first exhaust treatment fluid or the second exhaust treatment fluid from the electrochemical cell, and dose the one exhaust treatment fluid into the exhaust passage at a location upstream from the exhaust treatment component.

A method for operating a device configured to provide a dosed supply of a liquid. The device has: a pump delivering the liquid and having a pump housing having an inlet and an outlet, an eccentric on the pump housing, and a deformable diaphragm arranged between the pump housing and the eccentric. The deformable diaphragm and the pump housing delimit a delivery path from the inlet to the outlet and form at least one seal of the delivery path, the seal being displaceable along the delivery path by a movement of the eccentric to deliver the liquid. The method comprises: detecting a demanded dose amount of the liquid; activating the pump to deliver the liquid by the pump; stopping operation of the pump when the delivered amount of the liquid corresponds to the demanded dose amount; deactivating the pump when the eccentric is situated in a predefined park position.

An aftertreatment system for treating constituents of an exhaust gas includes: a housing defining a first internal volume and a second internal volume; an oxidation catalyst in the first internal volume and extending along a first axis, the oxidation catalyst configured to receive at least a portion of the exhaust gas via an inlet conduit fluidly coupled to the oxidation catalyst; a filter in the first internal volume and extending along a second axis parallel to and offset from the first axis, wherein an outlet of the filter is disposed within the second internal volume and configured to emit the exhaust gas into the second internal volume; at least one selective catalytic reduction (SCR) catalyst in the second internal volume and extending along a third axis that is perpendicular to the first axis; and a decomposition tube in the second internal volume in a direction parallel to the third axis.