An exhaust treatment system for a work vehicle includes a selective catalytic reduction (SCR) system having an SCR outlet for expelling treated exhaust flow therefrom, a flow conduit in fluid communication with the outlet, an exhaust sensor positioned within the flow conduit downstream of the outlet, and a flow mixer positioned upstream of the exhaust sensor. The flow mixer has an end wall defining sector openings circumferentially extending between first and second sector sides and radially between radially inner and outer sector ends. Moreover, the flow mixer has swirler vanes, where each of the swirler vanes extends circumferentially from the first sector side of a respective one of the sector openings and radially between radially inner and outer vane ends. Particularly, the radially outer vane end of each of the swirler vanes is spaced apart from the radially outer sector end of the respective one of the sector openings.

An exhaust gas purification device that allows suppressing an increase in pressure loss is provided. The exhaust gas purification device of the present disclosure includes a honeycomb substrate and an inflow cell side catalyst layer. The substrate includes a porous partition wall which defines inflow cells and outflow cells extending from an inflow side end to an outflow side end. The inflow cell side catalyst layer is disposed on a surface on the inflow cell side in an inflow cell side catalyst region from an inflow side end to a position close to an outflow side end of the partition wall. The permeability of a portion including an outflow side region from the position to the outflow side end of the partition wall is higher than a gas permeability of a portion including the inflow cell side catalyst region of the partition wall and the inflow cell side catalyst layer.

A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one temperature sensor at an underbody SCR system within the exhaust after-treatment system and a DEF injector upstream of a close-coupled SCR system within the exhaust after-treatment system. The DEF injector is operated to inject DEF into the exhaust gas flow at a rate that varies as a function of a temperature measured by the temperature sensor.

Methods and systems are provided for adjusting an ammonia (NH.sub.3) sensor output using readings of a nitrogen oxide (NOx) sensor, the NOx sensor having a sensitivity factor to NH.sub.3. In one example, a method may include determining and updating a gain value of the NH.sub.3 sensor during zero NOx conditions to be used to calculate a corrected NH.sub.3 sensor output value, and determining and updating an offset value of the NH.sub.3 sensor during zero NH.sub.3 conditions to be used to zero the NH.sub.3 sensor during zero NOx conditions.

An aftertreatment system includes a first dosing module, a second dosing module, and a reductant tank assembly. The reductant tank assembly includes a reductant tank, a header coupled to the reductant tank, and a first splitting device that splits a first flow from the header into a first inlet flow and a second inlet flow. A first inlet line and a second inlet line direct the first inlet flow and the second inlet flow to the first dosing module and the second dosing module. A first outlet line and a second outlet line direct a first outlet flow and a second outlet flow from the first dosing module and the second dosing module to a second splitting device. The second splitting device merges the first outlet flow and the second outlet flow into a second flow and provides the second flow to the header.

A catalyst-coated, plugged honeycomb body having a honeycomb structure with a matrix of porous walls forming a plurality of channels, at least some of the plurality of channels being plugged to form inlet channels and outlet channels. At least some of the porous walls are filtration walls and at least some of the porous walls are non-filtration walls. A catalyst is preferentially disposed on the non-filtration walls, wherein the catalyst being preferentially disposed comprises CR<0.2 wherein CR is a coating ratio defined as an average percent loading of a washcoat containing the catalyst on and within the filtration walls divided by an average percent loading of the washcoat containing the catalyst on and within the non-filtration walls. Methods and apparatus configured to preferentially apply a catalyst-containing slurry to the non-filtration walls are provided, as are other aspects.

An exhaust aftertreatment unit for cleaning exhaust gases. The exhaust aftertreatment unit includes an emission reducing module being a diesel particulate filter, DPF, and/or a diesel oxidation catalyst, DOC, a selective catalyst reduction, SCR, catalyst, an electrical heating element arranged upstream of the SCR catalyst, a casing housing at least the emission reducing module, and a service lid removably arranged to cover a service opening of the casing through which the emission reducing module may be accessed. The electrical heating element is removably arranged relative the casing and is arranged accessible upon removal of the service lid.

An exhaust system that includes a catalytic converter, selective catalytic reduction system, a muffler and, for certain applications, a diesel particulate filter that each include at least one filter that has an electric heating element, a metallic coating and a plurality of metal rods extending therethrough. The combination of elements are configured to heat the internal housings of the exhaust system and disrupt the direction of flow of exhaust gases which contain harmful toxic gases and pollutants and aid in removing and/or reducing said toxic gases and pollutants.

Systems and methods for controlling a gasoline urea selective catalytic reductant catalyst are described. In one example, an observer is provided that corrects an estimate of an amount of NH.sub.3 that is stored in a SCR. The amount of NH.sub.3 that is stored in the SCR is a basis for generating additional NH.sub.3 or ceasing generation of NH.sub.3.

An aftertreatment system for treating constituents of an exhaust gas produced by an engine, comprising: a housing; a selective catalytic reduction (SCR) system disposed within the housing; a reductant injector disposed on a sidewall of the housing upstream of the SCR system and configured to insert a reductant into the exhaust gas; and a vortex generator disposed in the housing, the vortex generator comprising at least one deflector disposed on a surface within the housing, the at least one deflector configured to generate vortices in a portion of the exhaust gas flow flowing over the at least one deflector such that the portion of the exhaust gas remains attached to the surface at a downstream location of the surface.