Methods and systems are provided for an exhaust gas aftertreatment device. In one example, a method may include adjusting one or more engine operating parameters to produce ammonia in an ammonia generating device in response to an ammonia demand.

A segmented, heated urea mixer and an exhaust system to control NOx emission from combustion engines comprising a plurality of elements, at least one element independently heatable by an external power source to a temperature above a temperature of another element. A method of using the exhaust gas mixer and an exhaust gas mixer system further comprising a controller is also disclosed.

The invention provides an emission control system for treatment of an exhaust gas stream of an engine, including an engine producing an exhaust gas stream; an SCR catalyst unit downstream from the engine and in fluid communication with the exhaust gas stream; and an ammonia generation system comprising a reservoir containing ammonium hydroxide and an ammonia injector, wherein the reservoir is in fluid communication with the ammonia injector and the ammonia injector is in fluid communication with the exhaust gas stream upstream of the SCR catalyst unit. A method of treating an exhaust gas stream of an engine is also provided, including the steps of heating ammonium hydroxide to produce gaseous ammonia and transferring the gaseous ammonia through an ammonia injector into the exhaust gas stream such that the gaseous ammonia disperses within the exhaust gas stream upstream of a SCR catalyst unit.

An aftertreatment system includes an inlet exhaust section, an outlet exhaust section, a first aftertreatment component, a first dosing module, and a second dosing module. The inlet exhaust section receives exhaust. The outlet exhaust section is in fluid communication with the inlet exhaust section. The first aftertreatment component receives the exhaust from the inlet exhaust section, treats the exhaust, and provides the exhaust to the outlet exhaust section. The first dosing module is positioned along the inlet exhaust section. The first dosing module is structured to selectively dose the exhaust with reductant. The second dosing module is positioned along the outlet exhaust section. The second dosing module is structured to selectively dose the exhaust with the reductant.

An automotive exhaust aftertreatment system for reducing effluents, such as nitrous oxides (NOx), in exhaust gasses passing through the system. The automotive exhaust aftertreatment system includes a doser, an active heating element, and a controller coupled to the doser and the active heating element. The doser is configured to feed a reducing agent into an exhaust stream moving through the exhaust aftertreatment system. The active heating element configured to produce heat from electrical energy and heat passageways that carry the reducing agent through the doser.

An after treatment system is disclosed. The after treatment system may include an exhaust pipe through which an exhaust gas flows; a three-way catalyst (TWC) mounted on the exhaust pipe and purifying HC, CO, and NOx contained in the exhaust gas, an ammonia production catalyst (APC) mounted on the exhaust pipe at a downstream of the TWC, storing NOx at a lean air/fuel ratio, and generating H.sub.2, releasing the stored NOx, and generating NH.sub.3 using the released NOx and the generated H.sub.2 at a rich air/fuel ratio, and a selective catalytic reduction (SCR) catalyst mounted on the exhaust pipe at a downstream of the APC, storing the NH.sub.3 generated in the TWC and the APC, and reducing the NOx contained in the exhaust gas using the stored NH.sub.3.

A reductant generator includes a housing defining a chamber, an inlet to direct engine exhaust gas into the chamber, a moveable member that receives driving input from an engine and which is configured to compress engine exhaust gases within the chamber, and a supply to provide a fluid into the chamber to be transformed into reductant. The generator also includes an outlet from which the reductant is directed into an exhaust system.

An automotive exhaust aftertreatment system for reducing effluents, such as nitrous oxides (NOx), in exhaust gasses passing through the system. The automotive exhaust aftertreatment system includes a dosing unit configured to inject primary and secondary reductant fluids into exhaust gasses based on various strategies to optimize operation of the system.

A method for monitoring a gas sensor (14) which comprises two electrochemical measuring cells (20, 30) and which is arranged in an exhaust tract (10) of an internal combustion engine (11), wherein the sensor elements (20, 30) exhibit a substantially identical sensitivity towards a first gas component and a different sensitivity towards a second gas component and are insensitive towards further gas components. In an operating state in which an exhaust gas stream at the gas sensor (14) contains less of the second gas component than of the first gas component a concentration of the first gas component is calculated from each of the sensor signals from the sensor elements (20, 30) and a defect in a sensor element (20, 30) is deduced from the concentrations of the first gas component.

A method for operating a feed module of an SCR catalytic converter system which has a feed pump, a feedback pump and a hydraulic interface channel. The feed module is operated in a test state in which a feed operation of the feed pump takes place and a feed operation of the feedback pump does not take place. Owing to a time profile of an MSP current (I.sub.MSP) of the feed pump it is decided in the test state whether the feed module is to change into a thawing state.