Abstract: The invention relates to an ammonia gas generator for producing ammonia from an ammonia precursor substance as well as the use thereof in exhaust aftertreatment systems. The invention further relates to a method for producing ammonia gas to reduce nitrogen oxides in exhaust gases, in particular combustion gases from internal combustion engines such as diesel engines.

Abstract: The present disclosure relates to a substrate comprising nanomaterials for treatment of gases, washcoats for use in preparing such a substrate, and methods of preparation of the nanomaterials and the substrate comprising the nanomaterials. More specifically, the present disclosure relates to a substrate comprising nanomaterial for three-way catalytic converters for treatment of exhaust gases.

Abstract: System to reduce the amount of NOx in exhaust gases of a vehicle. The system includes a storage space 1 containing an agent, a SCR catalytic converter 5, an injection module 6c to inject the agent upstream of the converter, a heat exchanger 2 containing a porous matrix, a shutter or injector 11 to control the flow rate of the agent to the exchanger, a valve 12 between the storage space and exchanger, to transfer thermal energy to gases during the starting period. The shutter or injector controls the flow of agent into the exchanger during the starting period to raise its temperature, and is closed when gases have reached a certain temperature. The valve regulates exchanger pressure during a period at operating temperature and conveys the agent to storage space when the exchanger pressure is higher than storage space pressure.

Abstract: The present invention relates to a method for generating ammonia from an ammonia precursor substance and to the use thereof for reducing nitrogen oxides in exhaust from industrial facilities, from combustion engines, from gas engines, from diesel engines or from petrol engines.

Abstract: A method for purifying exhaust gas of an internal combustion engine including flowing an exhaust gas containing NOx and a concentration of hydrocarbons in an exhaust gas passage that contains an exhaust purification catalyst, wherein the concentration of hydrocarbons is vibrated within a predetermined range of amplitude and period, and a least a portion of the hydrocarbons are reformed by the exhaust purification catalyst; reacting the NOx contained in the exhaust gas and the reformed hydrocarbons to produce a reducing intermediate; and chemically reducing, wherein at the time of engine operation, a demanded produced amount of the reducing intermediate required for chemically reducing the NOx is calculated, and the amplitude and vibration period of the concentration of hydrocarbons flowing into the exhaust purification catalyst are controlled so that an amount of the reducing intermediate produced becomes the demanded produced amount.

Abstract: Device for purifying exhaust gases from a thermal combustion engine, comprising a catalytic ceramic carrier comprising an arrangement of crystallites of the same size, same isodiametric morphology and same chemical composition or substantially the same size, same isodiametric morphology and same chemical composition, wherein each crystallite is in contact at a singular or almost singular point with surrounding crystallites, and whereon at least one active phase is deposited for the chemical destruction of impurities in the exhaust gas.

Abstract: A method for controlling injection of a reductant into an exhaust system of an internal combustion engine, which includes measuring temperature at a plurality of locations in the exhaust system relative to an SCR catalyst, determining an average temperature as a function of the measured temperatures, and controlling injecting of a reductant into the exhaust upstream of the catalyst as a function of the average temperature. The average temperature may be a weighted average where temperature measurements from at least some locations upstream of the SCR catalyst may be assigned greater weight than temperature measurements proximate the SCR catalyst.

Abstract: A method for controlling injection of a reductant into an exhaust system of an internal combustion engine includes determining the temperature and pressure of reductant supplied to a reductant injector. The method also determines a maximum reductant flow rate as a function of the reductant temperature and pressure and controls operation of the injector as a function of the maximum reductant flow rate.

Abstract: Device for the purification of exhaust gases from a thermal combustion engine comprising: one or several ceramic catalyst carriers comprising an arrangement of crystallites of the same size, same isodiametric morphology and same chemical composition, or approximately the same size, same isodiametric morphology and same chemical composition in which each crystallite is in point or quasi-point contact with the surrounding crystallites, and one or several active phases for chemical destruction of impurities in the exhaust gas comprising metallic particles having chemical interactions with said ceramic catalyst carrier and mechanical anchoring in said catalyst carrier such that coalescence and mobility of each particle are limited to a maximum volume corresponding to the volume of a crystallite of said ceramic catalyst carrier.

Abstract: A device for exhaust gas treatment in an exhaust system of an internal combustion engine, in particular in a motor vehicle, includes an electrically heatable honeycomb body through which an exhaust gas can flow. The honeycomb body is disposed in a casing tube and has at least one current-conducting structure with electric insulation for voltages greater than 24 V. A current-generating pulsed voltage is applied to the structure to heat the honeycomb body. It is thus possible for heating elements in the exhaust-gas flow to be powered by an on-board electrical system voltage of for example 48 V. A method for operating the honeycomb body is provided with which, even at operating voltages greater than 24 V, the generation of heat in the electrically heatable honeycomb body can be kept in a desired range by adjustment of a pulse width and/or repetition frequency of the pulsed voltage.

Abstract: An exhaust after-treatment system is described. Generally speaking, the system includes separate primary and secondary NOx reducing systems for delivering reductant (e.g. urea and ammonia) to an exhaust stream, a sensor system for determining relevant operating conditions and an electronic control module for activating the reducing systems. The two NOx reducing systems include flow control modules coupled to the electronic control module. Methods for reducing NOx in an exhaust stream are also described. Generally speaking, the methods include the steps of determining a need for NOx reduction in an exhaust stream, determining temperature of exhaust stream, and injecting at least one of a primary reductant and a secondary reductant into the exhaust stream based on the determined temperature of the exhaust stream. Typically, the primary reductant comprises urea and the secondary reductant comprises ammonia.

Abstract: An exhaust gas aftertreatment system for an internal combustion engine, particularly for a ship's diesel engine operated with heavy oil, has a SCR catalyst that uses ammonia as reductant. A nozzle is positioned upstream of the SCR catalyst viewed in flow direction of the exhaust gas. Using the nozzle, an aqueous urea solution is decomposed at a defined pressure and at a defined temperature to form water vapor, carbon dioxide and ammonia vapor such that ammonia evaporated by the nozzle is injected into the exhaust gas via the nozzle.

Abstract: A method for purifying exhaust gas of an internal combustion engine, including chemically reducing NOx that is contained in the exhaust gas when a concentration of hydrocarbons flowing into an exhaust purification catalyst is made to vibrate within a predetermined range of amplitude and within a predetermined range of period, wherein, during the chemical reduction, the NOx contained in the exhaust gas is reacted with reformed hydrocarbons to produce a reducing intermediate containing nitrogen and hydrocarbons, a reducing action of the reducing intermediate chemically reduces the NOx, and the NOx is chemically reduced without storing nitrates or with storing a fine amount of the nitrates in a basic layer of the exhaust purification catalyst.

Abstract: A catalytic converter apparatus for use in an exhaust system of an internal combustion engine includes a housing having a gas inlet and a gas outlet, and at least one catalytic substrate element disposed in the housing. The at least one substrate element is divided into a plurality of zones or sections, the zones at least partially separated from one another to inhibit heat flow. The zones can be at least partially separated with walls. The walls can include insulating material for reducing the mobility of heat radially outwardly. Each of the zones defines a generally separate flow passage connecting the inlet and outlet in fluid communication. The apparatus can heat more rapidly from a cold start compared with conventional catalytic converters.

Abstract: A method and system are described for the on-board treatment of a hydrocarbon-fueled internal combustion engine (ICE) exhaust gas stream to reduce CO2 emissions from the vehicle which include: a. contacting the exhaust gas stream with a CO2 sorbent capture agent on board the vehicle to produce a mixture containing modified CO2-containing sorbent and a treated exhaust gas stream with reduced CO2 content; b. separating the modified CO2-containing sorbent from the treated exhaust gas stream; c. passing the modified sorbent in heat exchange with heat from the ICE to release CO2 and regenerate the CO2 sorbent capture agent; d. recycling the regenerated CO2 sorbent for use in step (a); e. discharging the treated exhaust gas stream having a reduced CO2 content into the atmosphere; f. recovering and compressing the CO2 for temporary storage on board the vehicle.

Abstract: An engine exhaust gas treatment system includes an oxidation catalyst, a NOX adsorber, and a turbine. The oxidation catalyst and the NOX adsorber are fluidly connected to an exhaust manifold of the engine. The turbine is fluidly connected to, and downstream of the oxidation catalyst and the NOx adsorber.

Abstract: A flow device for an exhaust system includes a body that defines an interior cavity. An exhaust inlet passage is disposed in the interior cavity. An exhaust outlet passage is disposed in the interior cavity so that at least a portion of the exhaust inlet passage circumferentially surrounds at least a portion of the exhaust outlet passage. A doser is adapted to inject reductants into the interior cavity of the body such that the reductants are injected in the same general direction as the direction of flow of the exhaust gases.

Abstract: A honeycomb carrier for an exhaust gas-cleaning catalyst to clean e.g. an exhaust gas of an automobile particularly containing NOx, wherein the material for the honeycomb carrier is an aluminum magnesium titanate sintered product obtained by firing at from 1,000 to 1,700° C. a molded product formed from a raw material mixture comprising 100 parts by mass, as calculated as oxides, of a mixture comprising a Mg-containing compound, an Al-containing compound and a Ti-containing compound in the same metal component ratio as the metal component ratio of Mg, Al and Ti in an aluminum magnesium titanate represented by the empirical formula MgxAl2(1+x)Ti(1+x)O5 (wherein 0?x?1), and from 1 to 10 parts by mass of an alkali feldspar represented by the empirical formula (NayK1?y)AlSi3O8 (wherein 0?y?1).

Abstract: A supply system for a liquid includes a liquid tank, a supply line, a pump, a filter, and a device that makes it possible to purge the line, pump, and filter. The supply system further includes a non-return device preventing liquid from entering into these elements once they have been purged. In this system, the pump, filter and non-return device are combined in a compact module. The filter at least partly surrounds the pump. The non-return device is an integral part of a common housing that surrounds the filter and at least one part of the pump.

Abstract: A wall-flow filter comprises a catalyst for converting oxides of nitrogen in the presence of a reducing agent, which wall-flow filter comprising an extruded solid body comprising: 10-95% by weight of at least one binder/matrix component; 5-90% by weight of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof; and 0-80% by weight optionally stabilised ceria, which catalyst comprising at least one metal, wherein: the at least one metal is present throughout the extruded solid body alone or in combination with: is also present in a higher concentration at a surface of the extruded solid body; is also carried in one or more coating layer(s) on a surface of the extruded solid body; or both.

Abstract: A catalytic converter apparatus for use in an exhaust system of an internal combustion engine includes a housing having a gas inlet and a gas outlet, and at least one catalytic substrate element disposed in the housing. The at least one substrate element is divided into a plurality of zones or sections, the zones at least partially separated from one another to inhibit heat flow. The zones can be at least partially separated with walls. The walls can include insulating material for reducing the mobility of heat radially outwardly. Each of the zones defines a generally separate flow passage connecting the inlet and outlet in fluid communication. The apparatus can heat more rapidly from a cold start compared with conventional catalytic converters.

Abstract: The present invention relates to a process for reducing cold start emissions in an exhaust gas stream by contacting the exhaust stream with a combination of molecular sieves comprising (1) a small pore crystalline molecular sieve or mixture of molecular sieves having pores no larger than 8 membered rings selected from the group consisting of SSZ-13, SSZ-16, SSZ-36, SSZ-39, SSZ-50, SSZ-52 and SSZ-73 and (2) a medium-large pore crystalline molecular sieve having pores at least as large as 10 membered rings selected from the group consisting of SSZ-26, SSZ-33, SSZ-64, zeolite Beta, CIT-1, CIT-6 and ITQ-4.

Abstract: A three way catalyst includes an extruded solid body having by weight: 10-100% of at least one binder/matrix component; 5-90% of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof; and 0-80% optionally stabilised ceria. The catalyst also includes at least one precious metal and optionally at least one non-precious metal, wherein: (i) the at least one precious metal is carried in one or more coating layer(s) on the body surface; (ii) at least one metal is present throughout the body and at least one precious metal is carried in one or more coating layer(s) on a body surface; or (iii) at least one metal is present throughout the body, is present in a higher concentration at a body surface, and at least one precious metal is carried in one or more coating layer(s) on the body surface.

Abstract: Methods and systems include an operation to interpret a face-plugging index and/or a reduction in an expected oxidation efficiency of an oxidation catalyst disposed in an internal combustion engine aftertreatment system, and in response to the face-plugging index or the reduction oxidation efficiency reaching a threshold value, an operation to provide a catalyst element reversal command.

Abstract: A method includes providing: a selective catalytic reduction (SCR) catalyst disposed in an exhaust gas stream of an internal combustion engine, a reagent injector operationally coupled to the exhaust gas stream at a position upstream of the SCR catalyst, and a NOx sensor coupled to the exhaust gas stream at a position downstream of at least a first portion of the SCR catalyst. The method includes operating an extremum seeking controller to determine a first reagent injection amount corresponding to a predetermined slope of ?NOx/?ANR, the ?NOx/?ANR determined according to the NOx sensor, providing a reagent injection command in response to the first reagent injection amount, and injecting an amount of the reagent in response to the reagent injection command.

Abstract: A method for a model-based feedback control of an SCR system having at least one SCR catalytic converter. An SCR catalytic converter model of the SCR catalytic converter is used to control an injection of a reductant upstream of the SCR catalytic converter. In the SCR catalytic converter model, at least one reduction rate based on an Arrhenius approach and/or an SCR efficiency of at least one relevant reaction in the SCR catalytic converter is calculated. Deviations between a real system behavior and a simulated system behavior are adjusted using adaptation logic. In order to minimize the deviations between the model and the real system behavior and to achieve enhanced control accuracy, at least one adjustment parameter is used in the calculation of at least one reaction rate and/or the SCR efficiency, the adjustment parameter taking into consideration deviations between the real system behavior and the simulated system behavior.

Abstract: A process which solves the problem of supplying NO2 in accordance with requirements by means of temperature control of the precatalyst which is decoupled from the operating state of the engine. In an associated apparatus, a precatalyst which contains at least one oxidation component and whose temperature can be controlled independently of the operating state of the engine and an active SCR stage comprising an SCR catalyst with upstream metering facility for a reducing agent from an external source are arranged in series. A particle filter can be arranged between precatalyst and metering facility. The precatalyst preferably additionally contains a nitrogen oxide storage material.

Abstract: A method for monitoring a reducing agent solution composition in an exhaust gas system of an internal combustion engine with metered injection of the reducing agent solution upstream of an SCR catalytic converter comprises metering injection of the reducing agent solution into the exhaust gas stream, determining a measured variable of a change in water content in the exhaust gas stream in response to the injected reducing agent solution, and determining at least one indicator value of a composition of the reducing agent solution at least based on the determined measured variable. In this way, deviations from the standard composition may be taken into account during metering or be displayed as an error.

Abstract: A method for controlling a selective catalytic reduction system (SCR) exploiting a set of predetermined trigger events and a set point for the NOx concentration, and an arrangement for SCR. At the occurrence of a trigger event, NOx concentration measurement downstream from the catalyst elements is started and the difference between the measured concentration and the set point is determined. If the difference is negative, the dosing of the reducing agent is decreased. If the difference is positive, the dosing of the reducing agent is increased and after system stabilization a new measurement is started. If the measured value is below the previous measured value, the same dosing is maintained. If the measured value is above the previous measured value, the dosing is decreased with an amount greater than the increase after the previous measurement.

Abstract: The present invention relates to a process for preparing a catalyst, at least comprising the steps of adding a protecting agent to an aqueous solution of a metal precursor to give a mixture (M1), adding a reducing agent to mixture (M1) to give a mixture (M2), adding a support material to mixture (M2) to give a mixture (M3), adjusting the pH of mixture (M3), and separating the solid and liquid phase of mixture (M3). Furthermore, the present invention relates to the catalyst as such and its use as diesel oxidation catalyst.

Abstract: A hydrocarbon trap is provided for reducing cold-start hydrocarbon emissions. The trap is formed by extruding from about 60 to 80% by weight zeolite and from about 20 to 40% by weight of a binder to form an extruded zeolite monolith. A three-way catalyst and an oxygen storage capacity material may also be included in the trap. The hydrocarbon trap contains from about 5.0 to 8.0 g/in.3 zeolite, which provides increased hydrocarbon retention. The hydrocarbon trap may be positioned in the exhaust gas passage of a vehicle such that hydrocarbons are adsorbed on the trap and stored until the monolith reaches a sufficient temperature for catalyst activation.

Abstract: A catalysed filter for a positive ignition internal combustion engine comprises a porous filtering substrate having a total substrate length coated with a three-way catalyst washcoat composition comprising at least one precious metal selected from the group consisting of rhodium and one or both of platinum and palladium supported on a high surface area oxide, and an oxygen storage component, which composition being axially shared by a first zone comprising inlet surfaces of a first substrate length<total substrate length and a second zone comprising outlet surfaces of a second substrate length<total substrate length, wherein a sum of the substrate length in the first zone and the substrate length in the second zone?100% and wherein one or both of the following applies: a washcoat loading in the first zone>second zone; and a total precious metal loading in the first zone>second zone.

Abstract: Disclosed embodiments include methods of removing carbon dioxide from combustion gas from an engine of a vehicle, systems for removing carbon dioxide from combustion gas from an engine of a vehicle, vehicles, methods of managing carbon dioxide emissions from an engine of a vehicle, and computer software program products for managing carbon dioxide emissions from an engine of a vehicle.

Abstract: We disclose a novel filter and process that converts the wastes in automotive exhausts into carbon nanotubes. The filter surface is composed of iron of similar catalyst. The filter is placed along the pathway of exhaust streamlines preferably at an angle of more than 5°. and less than 15°. The filter is heated to temperatures in the range of 200-1000° C. The filter described in this invention can work in its own or supplement existing filtration systems. The end product of this filtration system is a material that is commercially valuable. The synthesized carbon nanotubes are purified using ionic liquid solution that is capable of removing undesirable carbonated material and leaving 95% purified carbon nanotubes. The purified carbon nanotubes have a diameter of 20-50 nm and a length of 1-10 micro meters.

Abstract: A catalyst composition is provided having a zeolite material of a CHA crystal structure and a silica to alumina mole ratio (SAR) of about 10 to about 25 and preferably having a mean crystal size of at least 1.0 microns; and a non-aluminum base metal (M), wherein said zeolite material contains said base metal in a base metal to aluminum ratio (M:Al) of about 0.10 to about 0.24.

Abstract: A selective catalytic reduction (SCR) assembly, and method of operating the assembly, is described. In one example, the SCR assembly includes an SCR line, a flow restrictor, and a pressure sensor. The SCR line carries a reducing agent such as urea, and the flow restrictor is located in the SCR line. The pressure sensor senses the pressure of the reducing agent flowing through the SCR line, and the sensed pressure can be used to do one or more of the following: i) monitor the functionality of the SCR injector, ii) as one or more bases for controlling operation of an SCR fluid pump, and/or iii) determine a volume or volumetric flow rate of reducing agent that is ejected into an exhaust stream.

Abstract: A method of making composite nanoscale particles comprising subjecting a starting material to laser energy so as to form a vapor and condensing the vapor so as to form the composite nanoscale particles, wherein said composite nanoscale particles comprise a first metal and/or a first metal oxide incorporated in nanoscale particles of an oxide of a second metal, the first metal being different than the second metal. The starting material can comprise first and second metals or compounds of the first and second metals. The composite nanoscale particles can be formed in a reaction chamber wherein a temperature gradient is provided. The atmosphere in the chamber can be an inert atmosphere comprising argon or a reactive atmosphere comprising oxygen. The composite nanoscale particles are useful for low-temperature and near-ambient temperature catalysis.

Abstract: System and methods for reducing secondary emissions in an exhaust stream from an internal combustion engine are disclosed. The systems and methods include a filtration device positioned downstream from an SCR catalyst of an aftertreatment system disposed in the exhaust system. The filtration device can also be used for particulate filter diagnostics and for treatment of ammonia slip.

Abstract: Methods and systems for improving operation of an SCR are disclosed. In one example, engine hydrocarbon emissions are reduced and/or directed to bypass an SCR so that SCR efficiency can be increased. The methods and systems may reduce NOx emissions of a vehicle via improving SCR efficiency.

Abstract: A method for cleaning the exhaust gas of an internal combustion engine, wherein nitrogen oxide in the exhaust gas is converted by means of hydrocarbons metered in a pulsed form into the exhaust gas duct, upstream of a nitrogen oxide catalytic converter.

Abstract: A method for operating an exhaust gas system for an internal combustion engine, in which the exhaust gas system includes at least one first catalytic coating and at least one second catalytic coating, the second catalytic coating being situated in the exhaust gas flow downstream from the first catalytic coating. An additional quantity of hydrocarbons is occasionally introduced into the exhaust gas upstream from the first catalytic coating so that a heat-generating reaction may take place in the second catalytic coating. With the aid of at least one temperature sensor and/or at least one hydrocarbon sensor and/or at least one lambda sensor upstream and/or downstream from the second catalytic coating, at least one property of the exhaust gas is ascertained which characterizes a reaction of the second catalytic coating due to the additional quantity of hydrocarbons.

Abstract: An exhaust gas treatment system for an internal combustion engine to control desulfurization of at least one aftertreatment device is provided. The exhaust gas treatment system includes a desulfurization mode trigger module, a desulfurization control module, and an interrupt module. The desulfurization mode trigger module is configured to set a desulfurization request based on one or more trigger conditions. The desulfurization control module is configured to control desulfurization of at least one aftertreatment device based on the desulfurization request. The interrupt module is configured to interrupt the desulfurization of at least one aftertreatment device based on an interrupt condition.

Abstract: Systems and method for adjusting a cone angle of injected reductant directed into an engine exhaust upstream of a catalytic device based on the temperature distribution within the catalytic device are disclosed. In one particular example, a dosing unit comprising an adjustable piston is described whose adjustment further controls the distribution and amount of reaction fluid delivered therefrom. In this way, the fluid flow shape may be controlled to achieve a more optimal exhaust gas conversion based on the prevailing conditions within the exhaust gas system.

Abstract: A catalyst of one or more complex oxides having a nominal composition as set out in formula (1): AxB1-y-zMyPzOn (1) wherein A is selected from one or more group III elements including the lanthanide elements or one or more divalent or monovalent cations; B is selected from one or more elements with atomic number 22 to 24, 40 to 42 and 72 to 75; M is selected from one or more elements with atomic number 25 to 30; P is selected from one or more elements with atomic number 44 to 50 and 76 to 83; x is defined as a number where 0<x?1; y is defined as a number where 0?y<0.5; and z is defined as a number where 0<z<0.2.

Abstract: A gas separation and recovery apparatus that separates and recovers nitrogen oxides from a gas mixture includes: a liquid storing portion that stores a liquid, the liquid absorbing the nitrogen oxides; a gas-liquid contacting portion in which the liquid and the gas mixture contact with each other; and a liquid recovering portion that recovers the liquid after the liquid contacts the gas mixture. The liquid is an ionic liquid that chemically absorbs the nitrogen oxides.

Abstract: Systems and methods are provided for a layered emission control device coupled to an exhaust manifold. Various formulations may be incorporated in a plurality of layers of the device to enable various emission control functions to be grouped within spatial constraints. For example, a first layer may include a first, oxidizing catalyst, a second layer may include a HC trap, and a third layer may include a second, different oxidizing catalyst, the second layer positioned between the first and third layers. The layers may be organized to reduce functional interference and improve functional synergy between the various emission control functions.

Abstract: The present invention relates to a process for reducing cold start emissions in an exhaust gas stream (such as from an internal combustion engine) by contacting the exhaust stream with a combination of molecular sieves comprising (1) a small pore crystalline molecular sieve or mixture of molecular sieves having pores no larger than 8 membered rings selected from the group consisting of SSZ-13, SSZ-16, SSZ-36, SSZ-39, SSZ-50, SSZ-52 and SSZ-73 molecular sieve and having a mole ratio at least 10 of (a) an oxide of a first tetravalent element to (b) an oxide of a trivalent element, pentavalent element, second tetravalent element which is different from said first tetravalent element or mixture thereof and (2) a medium-large pore crystalline molecular sieve having pores at least as large as 10 membered rings selected from the group consisting of SSZ-26, SSZ-33, SSZ-64, zeolite Beta, CIT-1, CIT-6 and ITQ-4 and having a mole ratio of at least 10 of (a) an oxide of a first tetravalent element to (b) an oxide of a tr

Abstract: A NOx selective reduction catalyst for reducing NOx by the ammonia adsorbed is disposed in an engine exhaust gas passage. As states of adsorption of ammonia by the catalyst, there are a first adsorption state of ammonia that occurs when the ammonia is adsorbed during low temperature and a second adsorption state of ammonia that occurs when the ammonia is adsorbed or has already been adsorbed during high temperature. The amount of adsorbed ammonia in the first state is restricted to control concentration of the ammonia that is in the first state and desorbed when the temperature of the catalyst increases so as to be not higher than an allowable concentration, and that in the second state is restricted to control concentration of the ammonia that is in the second state and desorbed when the temperature of the catalyst increases so as to be not higher than an allowable concentration.

Abstract: The invention relates to a system intended to reduce the amount of NOx in the exhaust gases of a motor vehicle. The system comprises a storage space (1) containing a reducing agent; an SCR (selective catalytic reduction) catalytic converter (5) for treating the exhaust gases laden with reducing agent, and an injection module (6c) designed to inject the reducing agent from the storage space (1) into the exhaust gases of the motor vehicle upstream of the SCR catalytic converter (5). The system further comprises: at least one heat exchanger (2) connected to the storage space (1) and containing a porous matrix intended to absorb the reducing agent originating from the storage space (1); a valve or an injector (11) downstream of the storage space (1) and upstream of the exchanger (2) and designed to control the addition of reducing agent to the exchanger (2), and a valve (12) positioned between the storage space (1) and the exchanger (2).

Abstract: A method is disclosed for operating an exhaust gas catalytic converter designed to reduce nitrogen oxides in an exhaust gas flow using a solution that contains urea and that reacts to form at least ammonia in the exhaust gas flow. The method may include: introducing an amount of the solution containing urea upstream of the exhaust gas catalytic converter until an ammonia slip through the exhaust gas catalytic converter; determining a first actual value of the loading state of the catalytic converter with ammonia at the time of the slip; determining a first estimated value of the loading state at the time of the slip by means of a dynamic model for the loading; subsequently draining the ammonia from the catalytic converter; determining a second actual value of the loading state of the exhaust gas catalytic converter with the solution containing urea when the catalytic converter is drained as specified.