An exhaust gas purification system for diesel engines of utility motor vehicles, includes an oxidation catalytic converter disposed in an exhaust tract, a reducing agent dosing device having a reducing agent injection device, a reducing agent decomposition device, a soot particle separator, a reduction catalytic converter and a muffler for the exhaust gases. The oxidation catalytic converter is disposed within a minimum distance directly downstream of outlet valves of the engine and a maximum distance of 0.75 m from an exhaust collecting pipe or an outlet of a turbocharger. The reducing agent decomposition device, the soot particle separator and the reduction catalytic converter are disposed separately from the oxidation catalytic converter.

An exhaust system comprising: a NOx storage catalyst; an electric heating element; and a NOx reduction catalyst wherein the heating element is located downstream of the NOx storage catalyst.

An after-treatment system includes, in series along an exhaust gas flow direction through the after-treatment system: a diesel oxidation catalyst (DOC), a diesel exhaust fluid (DEF) delivery device, a soot-reducing device and a selective catalytic reduction (SCR) catalyst.

Selective catalytic reduction systems are known and are generally included in exhaust systems of diesel engines in order to treat the exhaust gases of such engines. Such systems involve the introduction of diesel exhaust fluid (DEF) into exhaust gas flowing in an exhaust passage of an engine. When dosing DEF onto a hydrolysis catalyst in a SCR system, the DEF will under certain conditions cool the hydrolysis catalyst sufficiently to either slow down or effectively prevent ammonia release, which creates a lag or delay in the function of the hydrolysis catalyst. This limits the amount of control which can be exerted over ammonia storage in the SCR catalyst, and NOx conversion. In a first step, a set of measurement data is received from one or more sensors provided in the system. Subsequently, a first set of characteristics associated with a state of a component of the catalytic system, a second set of characteristics associated with an output of the catalytic system and a third set of characteristics associated with a bias and a scaling factor in the system are derived. In a third step, the derived sets of characteristics are used to control the catalytic system.

A reducing agent injection device includes a honeycomb structure having a honeycomb structure body and a pair of electrode members arranged in a side surface of the honeycomb structure body and a urea spraying device spraying a urea water solution in mist form. The urea water solution sprayed from the urea spraying device is supplied inside cells from a first end face of the honeycomb structure body, and urea in the urea water solution supplied in the cells is heated and hydrolyzed inside the electrically heated honeycomb structure body to generate ammonia. The ammonia is discharged outside the honeycomb structure body from a second end face and injected outside. There is provided a reducing agent injection device that can generate and inject ammonia from a urea solution with less energy.

The invention relates to a device for generating ammonia from an ammonia precursor solution, having a reaction space with an inflow connector through which an exhaust-gas flow can flow into the reaction space, having an outflow connector through which an ammonia-containing gas flow can exit the reaction space, and having a supply device by way of which selectively an ammonia precursor solution or a fuel can be supplied into the reaction space.

An after-treatment system includes, in series along an exhaust gas flow direction through the after-treatment system: a diesel oxidation catalyst (DOC) or a passive NOx adsorber (PNA), a diesel exhaust fluid (DEF) delivery device, a soot-reducing device and a selective catalytic reduction (SCR) catalyst, which may also include an additional PNA.

A process for detecting reductant deposits includes accessing data indicative of signal output from a radiofrequency sensor positioned proximate a decomposition reactor tube; comparing the data indicative of signal output from the radiofrequency sensor to a deposit formation threshold; and activating a deposit mitigation process responsive to the data indicative of signal output from the radiofrequency sensor exceeding the deposit formation threshold.

A multi-stage mixer includes a multi-stage mixer inlet, a multi-stage mixer outlet, a first flow device, and a second flow device. The multi-stage mixer inlet is configured to receive exhaust gas. The multi-stage mixer outlet is configured to provide the exhaust gas to a catalyst. The first flow device is configured to receive the exhaust gas from the multi-stage mixer inlet and to receive reductant such that the reductant is partially mixed with the exhaust gas within the first flow device. The first flow device includes a plurality of main vanes and a plurality of main vane apertures. The plurality of main vane apertures is interspaced between the plurality of main vanes. The plurality or main vane apertures is configured to receive the exhaust gas and to cooperate with the plurality of main vanes to provide the exhaust gas from the first flow device with a swirl flow.

An aftertreatment system for treatment of exhaust gases exiting an engine includes a first Selective Catalytic Reduction (SCR) device in fluid communication with the engine. The first SCR device receives the exhaust gases exiting the engine for reducing a first quantity of oxides of nitrogen (NOx) present in the exhaust gases. The aftertreatment system also includes an oxidation catalyst in fluid communication with the first SCR device. The oxidation catalyst receives the exhaust gases exiting the first SCR device for oxidizing ammonia present in the exhaust gases into a second quantity of NOx. The aftertreatment system further includes a second SCR device in fluid communication with the oxidation catalyst. The second SCR device receives the exhaust gases exiting the oxidation catalyst for reducing the second quantity of NOx.