Abstract: A catalyst temperature control system of the present disclosure includes a vehicle start anticipation module and an electrically heated catalyst (EHC) control module. The vehicle start anticipation module determines whether a vehicle start is anticipated based on at least one of a plurality of vehicle conditions before an ignition switch is turned on. The EHC control module activates an EHC based on the determination.

Abstract: A control device and method for exhaust gas purification that can prevent the adsorption amount from becoming excessively lower than the saturated adsorption amount and can prevent the reduction efficiency of the reduction catalyst from degrading, including a device which can predict a transition of the temperature of the reduction catalyst and determine whether that temperature is decreasing; an apparatus which can control injection of the reducing agent according to a first amount that is smaller than a saturated amount corresponding to the temperature of the catalyst if it is determined that the temperature does not decrease continuously for a time; and a second apparatus which can control the injection of the reducing agent according to a second amount that is larger than the first amount and smaller than the saturated amount if it is determined that the temperature of the reduction catalyst continuously decreases for a time.

Abstract: An engine exhaust aftertreatment system including an catalyst-based device configured to reduce an amount of NOx in exhaust gases produced by an engine using reductant stored in the catalyst-based device. The system includes a controller configured to determine a starting quantity of stored reductant in the catalyst-based device at the start of the engine. The starting quantity is based on a shutdown quantity of stored reductant in the catalyst-based device determined at the shutdown of the engine.

Abstract: A method for determining the amount of particulate that has accumulated in a particulate filter, comprising calculating an amount of particulate that has accumulated in the particulate filter on the basis of a physical model that uses measured and/or determined physical quantities, and subjecting the calculated particulate amount to validation on the basis of given validation criteria, the latter step envisaging validation of the calculated particulate amount in the case where said criteria are satisfied, and validation of a substitutive particulate amount which is a function of a previously validated amount and of an admissible rate of variation in the case where said criteria are not satisfied.

Abstract: An exhaust cleaning method and exhaust cleaning apparatus for an internal combustion engine (1) in which a fuel is fed and burned under periodical rich/lean combustion conditions. In a fuel reformer (18) disposed independently of an exhaust channel (11) in the engine (1), the fuel for the internal combustion engine (1) is reformed to produce a reformed gas containing carbon monoxide. The reformed gas is supplied to the exhaust to be introduced into an exhaust converter (17) having, disposed therein, a catalyst which adsorbs and reduces nitrogen oxides. The nitrogen oxides contained in the exhaust gas are adsorbed and reduced. Thus, the nitrogen oxides contained in the exhaust are removed at a high efficiency.

Abstract: A dosing control system for a vehicle includes a pump control module and an enabling/disabling module. The pump control module controls a pump that provides dosing agent to a dosing agent injector located upstream of a selective catalytic reduction (SCR) catalyst in an exhaust system. The enabling/disabling module disables the pump for a predetermined melting period after engine startup when the dosing agent is frozen and selectively activates the pump during the predetermined melting period to cool the dosing agent injector when a tip temperature of the dosing agent injector is greater than a predetermined temperature.

Abstract: A tank assembly (70) for storing a liquid reductant (74) includes a tank (78) defining a chamber (82), a filler tube (94) having an opening (102) and at least partially defining a fill passageway (98) from the opening (102) to the chamber (82), and a vent system (130). The vent system (130) includes a recirculation line (150) that provides fluid communication between the chamber (82) and the fill passageway (98). A float valve (174) in the recirculation line (150) prevents the conveyance of liquid (74) through the recirculation line (150).

Abstract: A regeneration control system for a vehicle includes a regeneration control module and a regeneration interrupt module. The regeneration control module selectively provides fuel to an oxidation catalyst for a regeneration event of a particulate filter that occurs during a predetermined melting period for frozen dosing agent. The regeneration interrupt module selectively interrupts the regeneration event and disables the provision of fuel to the oxidation catalyst before the regeneration event is complete when a temperature of a dosing agent injector that is located between the oxidation catalyst and the particulate filter is greater than a predetermined temperature.

Abstract: An engine starting method is disclosed. In one example, engine operation is adjusted to reduce catalyst light off time. Exhaust temperatures may be increased until a threshold engine temperature is reached.

Abstract: The invention relates to an ammonia tank of an exhaust gas treatment system of a vehicle, having a tank wall. The invention provides that the tank wall is surrounded by a reagent reacting with regard to ammonia.

Abstract: A fuel control system for a vehicle comprises a fuel control module, a heat release determination module, and a detection module. The fuel control module supplies fuel to a cylinder of a diesel engine for combustion within the cylinder. The heat release determination module determines a heat release value based on a pressure within the cylinder during the combustion. The detection module selectively indicates that the fuel is a diesel fuel alternative when the heat release value is less than a predetermined heat release value. The predetermined heat release value is less than a second predetermined heat release value associated with diesel fuel.

Abstract: A reductant dosing manifold is disclosed. The reductant dosing manifold may have a housing with a pump interface configured to directly connect the reductant dosing manifold to a reductant pump, and a reductant supply passage in fluid communication with the pump interface. The housing may also have a reductant outlet port, and a pressurized reductant passage connecting the pump interface to the reductant outlet port.

Abstract: A device for controlling the operating state of a catalytic converter in the exhaust line of an internal combustion engine, including a mechanism for determining the temperature upstream and downstream of the converter, a mechanism for injecting fuel in the exhaust line of the engine, a mechanism for calibrating a temperature model on a measured operating temperature of the catalytic converter, and a mechanism for calculating the integral of the difference between the measured temperature and the modeled temperature downstream of the converter.

Abstract: The present invention relates to a method of reducing coking over a Ag/Al2O3 hydrocarbon selective catalytic reduction catalyst in an exhaust stream of a lean burn internal combustion engine, the exhaust stream including hydrocarbon and NOx. The method includes controlling the hydrocarbon to molar NOx ratio of the exhaust stream so as to be within certain limits at certain temperatures. An exhaust system for a lean burn engine suited to the above method, and a lean burn internal combustion engine, or a vehicle or stationary power source including such an exhaust system are also included.

Abstract: A device for filtering particulates from an exhaust gas feedstream of an internal combustion engine includes a filter substrate having a multiplicity of alternately closed parallel flow passages having porous walls oriented parallel to a flow axis of the exhaust gas between an inlet and an outlet thereof, wherein subsets of the flow passages are associated with respective ones of a plurality of zones, a flow control valve to control flow of exhaust gas to each of the plurality of zones, a multi-zone heating element including a plurality of individually activated heating elements each corresponding to one of the plurality of zones.

Abstract: Provided is an exhaust gas combustion device which is capable of early prevention of clogging, and also a power generator including the device. An exhaust gas combustion device of the present invention includes: a DPF; a sensor which measures the pressure of exhaust gas to be introduced into the DPF; a sensor which measures the pressure of exhaust gas purified by the DPF; and a controller which receives outputs from both sensors and calculates a pressure difference. When the pressure difference is equal to or larger than a preset threshold, the heater is supplied with power from a power generating unit to thereby heat exhaust gas. Accordingly, PM accumulated inside the DPF is combusted and removed, preventing excessive clogging of the DPF even during light-load operation.

Abstract: A system and method according to which exhaust is directed from a stationary exhaust source and through a burner, and a combustible fluid is vented from at least one combustible fluid source other than the stationary exhaust source. The combustible fluid is captured and directed to flow from the combustible fluid source and towards the burner, and at least air is mixed the captured combustible fluid to form a mixture. The mixture is introduced into the burner and burned therein to thereby pre-heat the exhaust flowing therethrough. The pre-heated exhaust contacts a catalyst.

Abstract: An ECU performs atmospheric learning to correct an individual difference in an A/F sensor. In this case, when reducing fuel has been added before a fuel cut, the ECU calculates, at fixed intervals, the total amount of reducing fuel added and the total amount of oxygen flowing through an exhaust passage. The ECU then estimates the remaining amount of reducing fuel remaining in the exhaust passage using these total amounts, and performs atmospheric learning when the remaining amount is equal to or less than an allowable value. As a result, atmospheric learning can be accurately performed at the earliest possible timing even if the timing at which the reducing fuel is added or the operating state of an internal combustion engine or the like changes.

Abstract: A compression-ignition internal combustion engine system having an exhaust passage and an exhaust gas treatment arrangement, wherein the exhaust gas treatment arrangement comprises a three-way catalytic converter.

Abstract: A reductant delivery unit (10) includes a fluid injector (12) and a flange (20) coupled with the fluid injector. An exhaust boss (28) has a surface (39) defining a through-hole (40) that communicates with a vehicle's exhaust flow path. The flange is coupled to a mounting surface such that the outlet of the fluid injector communicates with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. A gasket (32) is sandwiched between the flange and the mounting surface. The gasket has a surface (37) defining a through-hole (38) therein that communicates with the through-hole in the exhaust boss to permit the urea solution to pass from the fluid outlet to the exhaust flow path. Gasket shielding structure (44) covers the surface defining the through-hole in the gasket to prevent the urea solution from contacting the gasket.

Abstract: An exhaust gas purification device is capable of diffusing and introducing a reducing agent into a NOx catalyst arranged in a downstream side exhaust gas passage. A housing of the device includes a main body in which an upstream side exhaust gas passage and the downstream side exhaust gas passage are housed, and a cap attached to a first surface of the main body provided with an outlet side opening of the upstream side exhaust gas passage and an inlet side opening of the downstream side exhaust gas passage. At least one of the first surface of the main body and a second surface in the cap which faces the first surface includes a guide portion, for guiding an exhaust gas flow, and a reducing agent diffusion portion, for facilitating mixing of the reducing agent with the exhaust gas.

Abstract: An injection device for injecting fuel, including a fuel supply path, through which fuel is able to be supplied, an injector having a spray orifice, from which the supplied fuel is ejected, a valve element, which is movable using an actuator, for opening the spray orifice and for closing it, and a throttle, which is situated in the fuel supply path, a distance of the throttle from the spray orifice along the fuel path having a length which is equivalent to the wavelength of a characteristic frequency of the injection device.

Abstract: An internal combustion engine according to the present invention includes an exhaust treatment apparatus provided in an exhaust passage, and a burner apparatus provided upstream of the exhaust treatment apparatus to raise exhaust temperature. A valve driving state of at least one of an intake valve and an exhaust valve is controlled so as to reduce a flow rate of exhaust gas passing through the burner apparatus when the flow rate of the exhaust gas is equal to or larger than a predetermined value. Possible flame blow-out in the burner apparatus can be prevented or suppressed to ensure sufficient ignition performance.

Abstract: A method for regenerating a particulate filter of an internal-combustion engine, provides for air to be supplied into the exhaust gas pipe upstream of the particulate filter in order to perform post-combustion in the exhaust gas pipe. The method provides for fuel to be supplied to the cylinders of the internal-combustion engine by means of a high-pressure pumping unit, and for fuel to be supplied into the exhaust pipe upstream of the particulate filter by means of the high-pressure pumping unit.

Abstract: The present invention provides a mixing device (1) for mixing urea with a gas, said urea being preferably dissolved in a fluid preferably water and said gas being preferably air. The mixing device comprises preferably a urea inlet (10) and a gas inlet (12) for feeding respectively urea and the gas into a mixing chamber (20) of the mixing device (4), and an outlet (14) for outlet of the mix of urea and gas from the mixing chamber (20), these inlets (10,12) and outlet (14) may preferably have a stream wise extension and runs preferably into the mixing chamber (20) and the outlet (14) originates preferably from the mixing chamber (20). Preferably, at least the gas inlet (12) for feeding air into the mixing chamber is designed so that depositing of urea crystals on selected surfaces of the said inlet is substantially (typically in the sense that deposited crystals does not clog the inlet) or totally avoided.

Abstract: An object of the present invention is to prevent an excessive temperature rise of a precatalyst in the case where the precatalyst is provided in the exhaust passage upstream of an exhaust gas purification apparatus and has a heat capacity smaller than that of the exhaust gas purification apparatus, and reducing agent is added from a reducing agent addition valve toward an upstream end surface of the precatalyst. According to the present invention, the reducing agent addition valve is located in such a way that the reducing agent added through it reaches the precatalyst in a liquid state.

Abstract: A method and an exhaust-gas treatment device for regenerating an exhaust-gas purification component include charging at least one capacitor and heating at least one sub-volume of the exhaust-gas purification component to at least 900° C. by supplying at least a part of the energy stored in the capacitor. A particle burn-off reaction can be started from the at least one sub-volume for a large volume of exhaust-gas purification components. Exhaust-gas purification components in an exhaust system of an internal combustion engine can thus be completely regenerated in an energy-efficient manner. A vehicle having the exhaust-gas treatment device and carrying out the method is also provided.

Abstract: An exhaust gas particulate filter system for an internal combustion engine comprises an exhaust gas conduit in fluid communication with, and configured to receive exhaust gas from, the internal combustion engine. A hydrocarbon supply is connected to the exhaust gas conduit and is in fluid communication with the exhaust gas for delivery of hydrocarbon thereto. A particulate filter assembly is located downstream of the hydrocarbon injector for receipt of the exhaust gas and hydrocarbon mixture. The particulate filter assembly comprises an exhaust gas filter disposed therein for removal of particulates from the exhaust gas and an electrically heated catalyst device disposed therein, upstream of the exhaust gas filter, and heatable to induce oxidation of the exhaust gas and hydrocarbon mixture and to heat the exhaust gas filter and burn particulates collected therein.

Abstract: In an exhaust gas purification apparatus for an internal combustion engine, the regeneration of a filter and the purification of NOx are made compatible with each other while suppressing an excessive supply of HC.

Abstract: An exhaust treatment system comprises M three-way catalysts and N electrically heated catalysts (EHCs). The M three-way catalysts are arranged to receive exhaust gas output by an engine of a hybrid vehicle. M is an integer greater than one. The N EHCs are arranged to receive the exhaust gas and provide radiant heat to the M three-way catalysts when the N EHCs are powered. N is an integer greater than one.

Abstract: An apparatus is provided for injection of a fluid for an exhaust gases treatment device of an internal combustion engine arrangement. The apparatus includes a fluid injector fed from a source of fluid under pressure through a fluid conduit, a feed valve in the fluid conduit between the source of fluid the said injector, a purge system including a gas conduit connecting a source of pressurized gas to the fluid conduit, a pressure limiter within the gas conduit, and a check valve downstream of the pressure limiter. The pressure limited by the pressure limiter is lower than the pressure of fluid delivered by the source of fluid.

Abstract: The invention relates to systems and methods for heating a solid or liquid reducing material such as an urea-containing material for NOx selective catalytic reduction (‘SCR’) using a heat stored in a thermal energy storage material, such as a phase change material. The stored heat may be heat from an exhaust waste, such as from an exhaust gas of an internal combustion engine. The reducing material may be a solid reducing material. Other reducing materials include aqueous solutions such as an aqueous solution containing, consisting essentially of, or consisting of urea and water. In one aspect, the process may include a step of evaporating an aqueous solution of urea for immediate urea hydrolysis.

Abstract: An airless nozzle and fuel deliver system for a fuel-fired burner sprays fuel droplets for ignition to increase heat for regenerating an exhaust component. A source of pressurized fuel delivers pressurized fuel to a first fuel injector. In response to a first control signal, the first fuel injector is opened and fuel pressure is increased to a desired level to open a valve such that the fuel can be delivered to the airless nozzle. The airless nozzle sprays fuel droplets for a period of time that the first fuel injector is open. In response to a second control signal, the first fuel injector is closed and a second fuel injector is opened such that fuel is vented to decrease fuel pressure between the valve and the first fuel injector to stop the spray of fuel droplets by closing the valve.

Abstract: A method of introducing reductant to an exhaust stream is disclosed. The method may include ordering a first dosing event, supplying a reductant to a dispensing device in response to ordering the first dosing event, dispensing reductant from the dispensing device into the exhaust stream, and forcing reductant from the dispensing device toward a reductant source, wherein sufficient reductant remains in a pumping device and a fluid passage to keep the pumping device primed.

Abstract: An engine exhaust aftertreatment system including a mixer disposed in the exhaust stream. The mixer includes a mesh section having a mesh of wires and may include a baffle section having a deflector that redirects a direction of flow of the exhaust stream. The mesh section may not extend across an entire width of an exhaust conduit containing the exhaust stream. The mesh section may also be sized and located to intersect the reductant introduced by the injector.

Abstract: An ammonia selective reduction-type NOx catalyst (48) is interposed in an exhaust passage of an engine (2) provided in a series-type hybrid electric vehicle (1), and a urea water injector (52) is disposed in the exhaust passage to supply a urea water into exhaust gas existing upstream of the ammonia selective reduction-type NOx catalyst (48). The engine (2) is started and stopped in accordance with the storage state of a battery (8), and the urea water injector (52) is controlled in accordance with the operating state of the engine (2). When the engine (2) is to be stopped, an adsorption increasing operation for increasing the amount of ammonia adsorbed by the ammonia selective reduction-type NOx catalyst (48) is executed over a predetermined period before the engine (2) is stopped.

Abstract: According to one representative embodiment, an apparatus for controlling reductant dosing in an SCR catalyst system having a reductant injection system configured to inject reductant into an exhaust gas stream includes a controller, an actual reductant dosing rate module, and a reductant doser compensation module. The controller is configured to determine a reductant dosing rate command representing a desired reductant dosing rate. The actual reductant dosing rate module is configured to determine a predicted actual reductant dosing rate based at least partially on the reductant dosing rate command. The reductant doser compensation module is configured to determine a modified reductant dosing rate command based at least partially on the predicted actual reductant dosing rate. The reductant injection system injects reductant into the exhaust gas stream at a rate corresponding to the modified reductant dosing rate command.

Abstract: Desulfation methods for an exhaust treatment system having a fuel reformer configured upstream of a LNT. Reductant is injected upstream of the fuel reformer. The reductant reacts within the reformer to generate heat, but the system is configured for some reductant to breakthrough and react in the LNT to generate further heat. This configuration allows the LNT to operate at temperatures higher the than first device and facilitates independent control of the LNT and first device temperatures.

Abstract: An NOx purification system having a selective reduction catalyst, adapted so that even when no ammonia or urea is supplied, NOx is converted to ammonia by a first catalyst including a lean NOx catalyst or a ternary catalyst at ammonia formation control and the ammonia is adsorbed by the selective reduction catalyst disposed downstream and so that by the adsorbed ammonia, there is carried out reduction purification of the NOx contained in the exhaust gas when no ammonia formation control is performed by the selective reduction catalyst. At the ammonia formation control, an ammonia adsorption target amount being a target value of ammonia adsorbed by the selective reduction catalyst is computed, and the ammonia formation control is carried out only when a cumulative value of an ammonia formation amount formed by the first catalyst at the ammonia formation control is under the ammonia adsorption target amount. Consequently, ammonia is stably supplied in just proportion to the selective reduction catalyst.

Abstract: An exhaust gas control apparatus includes an oxidation catalyst, a compact oxidation catalyst having a smaller cross section than that of an engine exhaust passage, a fuel supply valve, a glow plug, and an electronic control unit. The control modes for the exhaust gas control apparatus include a first control mode where the fuel is supplied from the fuel supply valve, heated by the glow plug, and ignited, a second control mode where the fuel is supplied from the fuel supply valve, and heated by the glow plug but is not ignited, and a third control mode where the fuel is supplied from the fuel supply valve and the glow plug does not provide heating. The electronic control unit selects the first or third control mode in the operation region where ignition is possible, and selects the second or third control mode in the operation region where ignition is not possible.

Abstract: A catalyst system comprising a first catalytic composition comprising a first catalytic material disposed on a metal inorganic support; wherein the metal inorganic support has pores; and at least one promoting metal. The catalyst system further comprises a second catalytic composition comprising, (i) a zeolite, or (ii) a first catalytic material disposed on a first substrate, the first catalytic material comprising an element selected from the group consisting of tungsten, titanium, and vanadium. The catalyst system may further comprise a third catalytic composition. The catalyst system may further comprise a delivery system configured to deliver a reductant and optionally a co-reductant. A catalyst system comprising a first catalytic composition, the second catalytic composition, and the third catalytic composition is also provided. An exhaust system comprising the catalyst systems described herein is also provided.

Abstract: A system for controlling the temperature of an exhaust stream includes a main exhaust passageway adapted to receive the exhaust stream from an engine. A bypass passage includes an inlet and an outlet in communication with the main exhaust passageway. The outlet is located downstream from the inlet. A burner is positioned within the bypass passage for treating the exhaust passing through the bypass passage. A valve is positioned within the main exhaust passageway downstream from the inlet and upstream from the outlet. The valve is operable to vary the exhaust flow through the burner. A controller selectively operates the burner to maintain a desired exhaust temperature downstream of the outlet.

Abstract: A dosing valve assembly is disclosed for administering a reducing agent into an exhaust stream from an internal combustion engine upstream of a catalytic converter and diesel particulate filter. The dosing valve assembly includes a control valve coupled to a source of reducing agent, a delivery valve constructed and arranged for coupling to the exhaust stream to enable a quantity of reducing agent to be administered into the exhaust stream, and an elongated conduit connecting the control valve and delivery valve for fluidly communicating reducing agent from the control valve to the fuel delivery valve. The disclosed arrangement enables the control valve to be displaced from the delivery valve and thus away from the high temperature environment proximal to the exhaust stream.

Abstract: Methods and systems are provided for operating an engine including an SCR catalyst downstream of an exhaust turbine and a particulate filter upstream of the turbine. In one example, the method comprises, adjusting a turbine wastegate to adjust a catalyst temperature to a desired catalyst temperature.

Abstract: A degree of dispersion of a reducing agent added to an exhaust gas flowing into an exhaust gas purification apparatus is controlled. Before addition fuel is added, a valve opening Vd of a flow area changing valve is changed to generate pulsation of the exhaust gas, so that addition valve vicinity exhaust gas pressure Pg varies periodically. Addition timing TMad is controlled to synchronize with extremum arrival timing TMe. High or low dispersion type addition control adds fuel at timing (CP) when the addition valve vicinity exhaust gas pressure Pg becomes a maximum value Pgmax, at timing (TP) when at a minimum value Pgmin, or at both timings (CP, TP).

Abstract: An exhaust-gas sampler is adapted to couple into an exhaust conduit and to sample a constituent of an engine exhaust flowing therein. The sampler comprises an envelope having upstream and downstream surfaces joined by a curved side surface. The upstream and downstream surfaces are each tangent to a plane substantially normal to a central axis of the exhaust conduit. A series of inlets are formed in the upstream surface, and an outlet is formed in the curved side surface. A sensor responsive to a level of the constituent in the exhaust is coupled in the envelope, at the peripheral region of the conduit.

Abstract: In an internal combustion engine, an NOx selective reduction catalyst (14) is arranged in an engine exhaust passage, and an NOx storage catalyst (12) is arranged in the engine exhaust passage upstream of the NOx selective reduction catalyst (14). When the amount of NOx stored in the NOx storage catalyst (12) exceeds a predetermined allowable value, the NOx storage catalyst (12) is raised in temperature to make the NOx storage catalyst (12) release the NOx. The amount of urea feed is decreased by exactly the amount of reduction of the calculated stored NOx amount with respect to the amount of urea feed determined from the engine operating state, and the amount of urea feed is increased by exactly the amount of reduction of the calculated released NOx amount with respect to the amount of urea feed determined from the engine operating state.

Abstract: A control system comprises a particulate matter (PM) filter, an electric heater, a first heating module, and a second heating module. The PM filter includes M zones that filter PM from exhaust gas. The electric heater includes M segments corresponding to the M zones that heat exhaust gas input to selected ones of the M zones when activated. The first heating module activates N of the M segments to heat exhaust gas input to N of the M zones to regenerate the N zones. The second heating module operates in one of a first mode and a second mode to regenerate other ones of the M zones after the N zones are regenerated. The first mode includes adjusting an air-fuel ratio of the exhaust gas. The second mode includes activating other ones of the M segments to heat exhaust gas input to other ones of the M zones.

Abstract: A flammable-gas led-out pipe (5) has a terminal end portion (5a) disposed in an exhaust-gas route (7) and a metal cylinder (10) is arranged at the terminal end portion (5a) of the flammable-gas led-out pipe (5). An oxidation catalyst (8) is disposed within the metal cylinder (10). On an upstream side of the oxidation catalyst (8), an air-supply passage (12) is opened to provide an outlet (12a) and the flammable gas (4) merges with supplied air (13). The flammable gas (4) is burnt with the oxidation catalyst (8) to produce catalyst-combustion heat, which is radiated from an outer peripheral surface of the metal cylinder (10) into the exhaust gas (9) in the exhaust-gas route (7) and the exhaust gas (9) heated by this heat-radiation is mixed with the flammable gas (4) that has passed through the oxidation catalyst (8).

Abstract: A method for monitoring the ammonia-selective catalyst reduction device includes monitoring states of parameters of the exhaust gas feedstream upstream of the ammonia-selective catalyst reduction device, analytically segmenting the ammonia-selective catalyst reduction device into a plurality of discrete substrate elements, sequentially calculating a change in ammonia storage for each of the discrete substrate elements, and determining a total ammonia storage concentration on the ammonia-selective catalyst reduction device based upon the sequentially calculated change in ammonia storage for each of the discrete substrate elements.