One-dimensional three-way catalyst model for control and diagnosis

Abstract

Engine exhaust procedure, which includes the following: Adjusting a fuel injection quantity based on a partial oxidation state of a catalyst, wherein the partial oxidation state is based on the reaction rates of two or fewer groupings of exhaust gas types in a catalyst and a one-dimensional model of space and time averaged mass balance and energy balance equations for a fluid phase and an intermediate layer of the catalyst.

Description

Area

[0001] The present disclosure relates to the regulation of the air-fuel ratio in an internal combustion engine. Background and Summary

[0002] Exhaust gas purification in a gasoline engine using a catalytic converter is most efficient when the air-fuel ratio of the catalyst feed gas is close to stoichiometry. During real-world operation of a gasoline engine, deviations from stoichiometry can occur. Generally, cerium dioxide is added to a catalyst to act as an oxygen storage buffer, helping to throttle emission breakthrough and widen the operating window around the stoichiometric air-fuel ratio. The stored oxygen can be maintained at a desired setpoint based on catalyst monitoring sensors and / or physics-based catalyst models.

[0003] DE 10 2013 204 422 A1 discloses a zero-dimensional three-way catalyst model for control and diagnostics. DE 103 07 457 A1 discloses a method for operating a nitrogen oxide storage catalyst of an internal combustion engine.

[0004] One approach to controlling and diagnosing exhaust emissions uses a physics-based model to determine the level of oxygen stored in a catalyst. This model contains multiple partial differential equations in one or more dimensions with several exhaust gas types. Another approach uses an axially averaged, physics-based, zero-dimensional model that includes several exhaust gas types, which may be grouped into an oxidizing agent group and a reducing agent group.

[0005] However, the inventors identified a problem with the approaches described above. Determining the level of stored oxygen using a model containing multiple partial differential equations in one or more dimensions can be difficult to implement and may require more processing power than is typically available in a power machine controller. Furthermore, using a zero-dimensional model can neglect parameters and may not accurately predict cold-start emissions due to the reduced order of the model.

[0006] Consequently, in one example, the above problem can be at least partially addressed by a method for an engine exhaust system. In one embodiment, the method comprises adjusting a fuel injection quantity based on the partial oxidation state of a catalyst, wherein the partial oxidation state is based on the reaction rates of the exhaust gas types in a one-dimensional model with space- and time-averaged mass balance and energy balance equations for a fluid phase and an intermediate layer of the catalyst. The transverse gradient is accounted for in the inner and outer mass transfer coefficients. This can improve the computation time of the one-dimensional model by grouping the chemical exhaust gas types into two or fewer groups, which may contain an oxidizing agent group and a reducing agent group, and using a single value for diffusivity.

[0007] The partial oxidation state can be determined, for example, based on a one-dimensional model derived from a detailed two-dimensional model. This model can track the evolution of two or fewer grouped chemical exhaust gases through the catalyst. Furthermore, the model also accounts for diffusion within the interlayer, where the reactions take place, by employing a concept of effective mass transfer. In this way, a simplified one-dimensional model can be used to predict both the total oxygen storage capacity and the partial oxidation state of the catalyst. These predictions can then be used to control the air-fuel ratio of the engine to maintain the partial oxidation state of the catalyst at a target quantity.Furthermore, the deterioration of the catalyst can be indicated if the catalyst activity or the total oxygen storage quantity falls below a threshold.

[0008] The present disclosure can offer several advantages. For example, the processing resources used for the catalyst model can be reduced. Furthermore, exhaust gas purification can be improved by maintaining the catalyst at a target partial oxidation state. In addition, emissions during a cold start can be accurately predicted for real-time fuel injection control. Another advantage of the present approach is that it provides non-intrusive catalyst monitoring for control and diagnostics, which is less dependent on sensor location and consequently equally applicable to both partial and full-volume catalyst systems.

[0009] The above advantages and further advantages and features of the present description will be readily apparent from the following detailed description, whether considered alone or in conjunction with the accompanying drawings.

[0010] It should be self-evident that the above summary is provided to introduce, in simplified form, a selection of the concepts that are further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that eliminate all the disadvantages stated above or in any part of this disclosure. Brief description of the drawings Fig. Figure 1 schematically shows an example vehicle system. Fig. Figure 2 illustrates a control operation for estimating catalyst gain. Fig. Figures 3A-3C show schematically exemplary graphical representations of the control strategies of the inner and outer loops. Fig. Figure 4 is a flowchart illustrating an exemplary method for monitoring a catalyst according to an embodiment of the present disclosure. Fig. Figure 5 is a flowchart illustrating an exemplary method for determining an oxidation state of a catalyst according to an embodiment of the present disclosure. Detailed description

[0011] To reduce emission breakthrough, catalysts can use an oxygen storage material, e.g., cerium dioxide in the form of cerium oxide, to provide a buffer for oxygen during rich or lean mixture deviations. The air-fuel ratio entering the catalyst can be controlled, for example, to maintain the catalyst's oxidation state at a target level. In an exemplary model presented in this disclosure, the concentration of various exhaust gas types, such as H2, CO, NOx, HC, and O2, from the inlet to the outlet of the catalyst can be modeled using a simplified one-dimensional model that groups the different exhaust gas types into two or fewer mutually exclusive groups. The model accounts for the complex catalyst dynamics, such as...The model simplifies the dynamics into a set of equations averaged over space and time, with a reduced number of chemical species achieved by grouping them into only two or fewer. The model equations track the equilibrium of only these two or fewer groups of exhaust gas species in the fluid phase and the catalyst interlayer. The model can accurately predict emissions during cold starts, while reducing the computational demands for real-time fuel injection control during engine operation. Furthermore, the model compensates for the overall energy balance in the fluid phase and the catalyst interlayer.

[0012] In particular, the model can track changes in the concentration of two groups of exhaust gas compounds, such as an oxidizing agent group and a reducing agent group, to determine a partial oxidation state of the catalyst, which can be used to control the engine's air-fuel ratio. Grouping the chemical exhaust gas compounds into oxidizing and reducing agent groups further reduces the real-time control of fuel injection because both groups can be chosen to have nearly identical molecular masses, and allows a single value for diffusivity to be used. Additionally, catalyst gain can be determined and applied to the model to track changes in the total oxygen storage capacity, which can indicate whether the catalyst is degraded or not. Fig. Figure 1 shows an exemplary power engine that includes a catalyst and a control system. Fig. Figures 2-5 illustrate different control routines that are executed by the power engine. Fig. 1 can be executed.

[0013] Fig. Figure 1 shows a schematic representation of a vehicle system 6. The vehicle system 6 includes a multi-cylinder engine 10. The engine 10 includes an inlet 23 and an outlet 25. The inlet 23 includes a throttle valve 62, which is fluidically coupled to the engine's inlet manifold 44 via an inlet channel 42. The outlet 25 includes an outlet manifold 48, which leads to an outlet channel 35 that directs the exhaust gas to the atmosphere. The outlet 25 can include one or more exhaust aftertreatment devices 70, which may be mounted in a closely coupled position within the outlet. One or more exhaust aftertreatment devices may include a three-way catalytic converter, a lean NOx trap, a diesel or gasoline particulate filter, an oxidation catalyst, etc. It is recognized that other components may be included in the engine, such as various valves and sensors.

[0014] The engine 10 can receive fuel from a fuel system (not shown) that includes a fuel tank and one or more pumps to pressurize the fuel supplied to the injectors 66 of the engine 10. While only a single injector 66 is shown, additional injectors are provided for each cylinder. It can be seen that the fuel system can be a non-recirculating fuel system, a recirculating fuel system, or various other types of fuel system. The fuel tank can contain multiple fuel mixtures, including fuels with a range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, etc., and combinations thereof.

[0015] The vehicle system 6 may further include a control system 14. It is shown that the control system 14 receives information from several sensors 16 (various examples of which are described here) and sends control signals to several actuators 81 (various examples of which are described here). As an example, the sensors 16 may include an exhaust gas sensor 126 (such as a linear UEGO sensor) located upstream of the exhaust gas purification device, a temperature sensor 128, and a downstream exhaust gas sensor 129 (such as a binary HEGO sensor). Other sensors, such as pressure, temperature, and composition sensors, may be coupled to various locations within the vehicle system 6, as discussed in more detail here.In one example, an actuator can contain a "message center" that includes an operating indicator 82. In response to a signal indicating catalyst deterioration, a message can be sent to a vehicle operator indicating the need to service the emissions system. In another example, the actuators can include a fuel injector 66 and a throttle valve 62. The control system 14 can include a controller 12. The controller can receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or code programmed according to one or more routines within it. Exemplary control routines are given here with respect to the... Fig. 2-5 described.

[0016] For catalyst diagnostics, various input parameters can be used in a catalyst model. In one embodiment, the input parameters can include the catalyst gain, an air quantity (AM), such as an air mass flow rate from the MAF sensor, a catalyst temperature estimated based on the engine's operating conditions, such as speed, load, etc., a HEGO output, and a UEGO output. In some embodiments, all of the exemplary inputs listed above can be used in the catalyst model. In another embodiment, a HEGO model can be used in series with the catalyst model. In such a model, the estimated model voltage is compared with the measured sensor voltage (e.g., the HEGO voltage), and the calculated error is then used to determine the catalyst activity (a cto update the catalyst activity. This catalyst activity is used as an indicator of the catalyst's age for diagnostic purposes. This model-based approach is non-intrusive and less dependent on the location of the HEGO sensor, making it equally valid for both partial and full-volume catalysts. In other embodiments, only a subset of the input parameters can be used, such as the catalyst temperature and catalyst gain.

[0017] Catalyst gain is an online estimate of the catalyst's oxygen storage capacity, which decreases as the catalyst ages, and is in Fig. 2 illustrates the exemplary function according to Fig. Figure 2 shows that the catalyst gain is a function of the air mass, the catalyst temperature, and the relative air-fuel ratio of the exhaust gases (e.g., lambda). The catalyst gain can indicate the catalyst conditions, such as the amount of oxygen stored in the catalyst, the catalyst conversion efficiency, etc.

[0018] Fig. Figure 2 illustrates an example function 200 for calculating the catalyst gain from the UEGO and HEGO sensor inputs. The catalyst gain can be defined as a linear, time-independent system that responds as a pulse to the inputs described above. Determining the catalyst gain relies on transfer functions (TFs) that represent the relationship between the inputs and outputs in the system. The two transfer functions (TFs) are shown below in the Laplace domain, where s is the Laplace operator: as+a Transfer function 1 (TF1) b(s)conv([xy],[xz])(s) Transfer function 2 (TF2)

[0019] Here, w = conv(u, v) convolves the vectors u and v. Algebraically, the convolution is the same operation as multiplying the polynomials whose coefficients are the elements of u and v.

[0020] Determining the catalyst gain at 210 involves determining the output of TF1 using the input from the HEGO sensor. This output can be fed into the output of TF2, as described in more detail below. At 212, the difference between the output of the UEGO sensor and lambda (e.g., 1) is determined, and this difference is multiplied by the air mass at 214. This product is used as the input for TF2 at 216. Since the catalyst gain can be continuously calculated and updated, the output of the previous catalyst gain determinations at 218 can be fed into the function. The product of TF2 and the previous catalyst gain can be added to the output of TF1 at 220. At 222, the difference between the input from the HEGO sensor and the product from 220 is determined, and this is multiplied by the output of TF2 at 224.To determine the catalyst gain, K, the integral of the product determined in 224 is calculated at 226.

[0021] Fig. Figures 3A-3B are exemplary graphical representations illustrating the control strategies of the inner and outer loops for maintaining the air-fuel ratio in a power engine. The power engine 10 and the exhaust gas purification device 70 are shown below. Fig. 1 are non-limiting examples of power machine components that can be monitored and / or controlled using the following control strategies. Fig. Figure 3A presents an exemplary graphical representation 300, which includes an inner loop 302 and an outer loop 304. The control strategy of the inner loop 302 includes a first air-fuel controller C1 306, which supplies a fuel command to the engine 308.

[0022] The engine produces exhaust gas, the oxygen concentration of which is determined by an upstream sensor, such as a UEGO 310, before it reaches a catalyst, such as the TWC 312. The outer loop 304 contains the feedback from a downstream oxygen sensor, such as a HEGO 314, which is fed into a second air-fuel controller C2 316. The output from a catalyst gain model 318 (see Fig. 2), which receives an input from the UEGO 310, the power unit 308 and the HEGO 314, is fed into the catalyst model 320 (see Fig. 5) As explained in more detail below, the catalyst model determines the total oxygen storage capacity and the partial oxidation state of the catalyst. A difference can be determined between the output of C2 and the UEGO signal at 322, which is output as an error signal to the first controller C1.

[0023] Fig. 3B presents an exemplary graphical representation 330, which relates to the control strategy of the graphical representation 300 according to Fig. 3A is similar, except that the catalyst model 320 receives input from a HEGO model 324 instead of the catalyst enhancement model. The HEGO model 324 can be used in series with the catalyst model 320. The HEGO model 324 compares the HEGO voltage as predicted by the catalyst model 320 with the measured HEGO voltage. The calculated error is then used to determine the catalyst activity (a c to update.

[0024] Fig. 3C presents an exemplary graphical representation 340 with a control strategy, where the catalyst model 320 receives inputs from both the catalyst enhancement model 318 and the HEGO model 324.

[0025] Fig. Figure 4 is a flowchart illustrating a method 400 for monitoring a catalyst according to an embodiment of the present disclosure. The method 400 can be implemented by a power machine control system, such as the control system 14 according to Fig. 1, using feedback from various force machine sensors. In 402, method 400 includes determining the catalyst gain. The catalyst gain can be determined according to the above regarding Fig. The process described in section 2 is used to determine the concentration of the grouped exhaust gases at the catalyst inlet. In this case, the concentration of the grouped exhaust gases at the catalyst inlet is determined. Determining the inlet gas concentrations can involve determining the concentration of two or fewer groups, including O2, H2O, CO, HC, NOx, H2, and CO2. Furthermore, the gases can be grouped into an oxidizing agent group and a reducing agent group. The inlet gas concentrations can be determined based on the air mass and / or the temperature and / or the air-fuel ratio and / or the engine speed and / or the spark timing and / or the load. The grouped gas concentrations can be mapped offline to the air mass, temperature, air-fuel ratio, and engine speed, with the concentrations being stored in a lookup table in the control system's memory.

[0026] In Figure 406, the catalyst gain and the species concentrations are inputted into a catalyst model. In another embodiment, a HEGO model is used to update the catalyst activity in real time instead of the catalyst gain. The catalyst model includes a set of equations averaged over space and time, an equilibrium in the catalyst's fluid phase for the grouped species, an equilibrium in the catalyst's interlayer for the grouped species, an energy balance of the fluid phase and interlayer, and the oxidation / reduction equilibrium of the cerium dioxide in the catalyst. In Figure 408, the total oxygen storage capacity and the partial oxidation state of the catalyst are determined from the catalyst model, which is subsequently discussed with regard to Fig. This is explained in more detail in section 5. At position 410, the fuel injection is adjusted to maintain a target partial oxidation state. For example, it may be desirable to maintain the partial oxidation state of the catalyst (e.g., the partial oxidation of the cerium dioxide in the catalyst) at a target level calibrated based on engine load and engine temperature, such as 50%, for optimal performance.

[0027] Procedure 412 determines whether the total oxygen storage capacity of the catalyst exceeds a threshold value. The total oxygen storage capacity of the catalyst indicates its condition; for example, a new catalyst has a relatively high oxygen storage capacity, while a deteriorated catalyst has a relatively low oxygen storage capacity due to the reduced capacity of the cerium dioxide to store oxygen. The total oxygen storage capacity of a new catalyst can be determined based on the amount of cerium dioxide present in the catalyst during its manufacture or during the catalyst's initial operation. The threshold value can be a suitable level below which the catalyst ceases to efficiently control emissions.If the total oxygen storage capacity is greater than the threshold, no deterioration is indicated at 414, and procedure 400 is then returned. If the total oxygen storage capacity is not greater than the threshold, i.e., if the oxygen storage capacity is less than the threshold, catalyst deterioration is indicated at 416, and a predetermined action is taken. The predetermined action may include notifying a vehicle operator via a malfunction indicator lamp, setting a diagnostic code, and / or adjusting the engine's operating parameters to reduce emission generation. Procedure 400 is then returned.

[0028] Fig. Figure 5 is a flowchart illustrating a procedure 500 for determining the oxidation state of a catalyst using a catalyst model. Procedure 500 can be performed during the execution of procedure 400 according to Fig. 4 is carried out by the power machine control system 14. At 502, the mass balance for the fluid phase of the catalyst is calculated for each group of species. The mass balance accounts for the transfer of mass from each group of species from the fluid phase to the intermediate layer. The mass balance for the fluid phase can be calculated using the following equation (1): ∂xfm∂t=−〈u〉∂xfm∂x−kmoRΩ(Xfm−〈XWC〉)

[0029] X is X fm The mole fraction of the gaseous type in the bulk fluid phase is 〈X WC 〉 the mole fraction of the type in the interlayer, is R Ωthe hydraulic radius of the channel, (u) is the average feed gas velocity and K is mo the mass transfer coefficient between the fluid and the intermediate layer, which is known as: kmo−1=kme−1+kmi−1 is defined. Here are k me and k mi The outer and inner mass transfer coefficients. The gradient in the transverse direction is taken into account by using the inner and outer mass transfer coefficients, which are calculated using Sherwood number correlations (Sh). The outer mass transfer coefficient k me is known as: kme=DfSh4RΩ defined. Here is D f a matrix of the diffusivity of the gas phase and Sh is a diagonal matrix defined by Sh = Sh ∞ l is given, where I is the identity matrix.

[0030] A position-dependent Sherwood number Sh, defined for fully developed flow with a constant flow boundary condition, is Sh=Sh∞+0.272(Pz)1+0.083(Pz)23, where Sh1 = 3:2 applies to a rounded square channel.

[0031] Similarly, the concentration gradient within the interlayer and the diffusion effect are captured by the internal mass transfer coefficient, which is expressed as: kmi=DsShiδc is defined, where D s the matrix of the diffusion coefficients of the intermediate layer is and Sh i the matrix of inner Sherwood numbers, which is evaluated as a function of the Thiele matrix φ: Shi=Shi,∞+(I+ΛΦ)−1ΛΦ2.

[0032] The effective velocity constant is given by: kieff=(−1cTotalRi(X)Xi)X=Xfm defined, where in this case φ 2 a diagonal matrix is ​​formed, where the diagonal terms are: Φii2=δc2Ds,iki,eff are defined. Grouping the chemical exhaust gas types into an oxidizing agent group and a reducing agent group allows the use of a single diffusivity value, since both groups have nearly similar molecular masses. In one example, the oxidizing agent and reducing agent groups are specifically selected to provide a single diffusivity value. This same value is used in the one-dimensional model for both the oxidizing agent and reducing agent groups in real time during engine operation when determining the different types and values ​​in the model. These values ​​are then used to adjust the fuel injection to achieve the target states of the oxidizing agents and reducing agents above the catalyst.Such advantageous operation is particularly suitable for the one-dimensional model compared to other models due to the unambiguous interaction between the two grouped species under the various simplifications and mathematical manipulations described here. Consequently, the methods described here, which estimate the various parameters, can incorporate a single value for diffusivity, with the same single value being used for both the grouped oxidizing agents and the grouped reducing agents in the diagonal matrix during engine operation, thereby improving the determination and actual injection of fuel quantities into the engine.

[0033] At 504, the mass balance for the interlayer for each group of species, taking into account the contribution of mass transfer from the interface to the volume interlayer and consumption due to the reaction, is calculated using the following equation (2): εw∂〈XWC〉∂t=1CTotalvTr+kmoδc(Xfm−〈XWC〉) calculated. Here, r is the reaction rate, and ε is the reaction rate. w the porosity of the intermediate layer, v represents the stoichiometric matrix and δ is c the thickness of the intermediate layer.

[0034] At 506, the energy balance for the fluid phase is calculated using the following equation (3): ρfCpf∂Tf∂t=−〈u〉ρfCpf∂TfRΩ(Tf−Ts), where ρ f the average density of the gas is T f the temperature of the fluid phase is T s the temperature of the solid phase is Cp f where is the specific heat capacity and h is the heat transfer coefficient.

[0035] At 508, the energy balance for the intermediate layer is calculated using equation (4): δwρwCpw∂Ts∂t=δwkw∂2Ts∂x2+h(Tf−Ts)+δcrT(−ΔH), where δ c the thickness of the intermediate layer is and δ w the effective wall thickness (which is defined as the sum δs + δc, where δs is the half-value thickness of the wall), where ρ w and Cρ w The effective density and the specific heat capacity are known as: δwρwCpw=δcρcCpc+δsρsCps and δwkw=δckc+δsks are defined, where the lower indices s and c represent the support and the catalyst intermediate layer, respectively.

[0036] At 510, the rate of oxidation of cerium dioxide is calculated using the following equation (5): ∂θ∂t=12TOSC(rstore−rrelease)

[0037] Where r store and r releasethe reaction rates for the oxidation and reduction of cerium dioxide are and θ is the partial oxidation state of cerium dioxide (FOS), θ=[Ce2O4][Ce2O4]+[Ce2O3].

[0038] The storage speed (r2), r store , and the rate of release (r3), r release The conversion of oxygen from cerium dioxide can be based on the following equations: r2=acA2exp(−E2RT)XO2(1−θ)TOSCgreen, r3=acA3exp(−E3RT)XA(θ)TOSCgreen.

[0039] This is a cThe catalyst activity or the catalyst aging parameter. The catalyst aging parameter indicates the oxygen storage state of the catalyst. For example, as the catalyst ages, its capacity to store oxygen may decrease. In one example, an aging parameter of one indicates a fresh catalyst, with decreasing aging parameters indicating a reduced capacity to store oxygen. The aging parameter can be based on volume estimates of the upstream air / fuel ratio, the downstream air / fuel ratio, the air mass, and the temperature. In some embodiments, the aging parameter can be calculated from the predetermined catalyst gain, which is determined with respect to Fig. 2 has been described. In a further embodiment, a HEGO model is used in series with the catalyst model to estimate the downstream HEGO voltage, and then, using the measured HEGO voltage, an error is calculated which is used to update the catalyst activity.

[0040] The terms A and E represent the prefactor of the exponential function and the activation energy, respectively. A and E are tunable parameters that can be optimized offline using a genetic algorithm or other nonlinear constrained optimization.

[0041] At 512, the partial oxidation state (FOS) and the total oxygen storage capacity (TOSC) are determined. The FOS can be determined using the equation above for θ. The TOSC represents the total oxygen storage capacity, and because each cerium dioxide molecule (Ce₂O₃) stores half a mole of oxygen, the TOSC can be equivalent to half the total cerium dioxide capacity.

[0042] The initial and boundary conditions for the above equations are: Xfm,j(x,0)=Xfm,j0(x),〈XWC,j(x,0)〉=〈XWC,j0(x)〉, Tf(x,0)=Tf0(x),Ts(x,0)=Ts0(x), θ(x,0)=θ0(x), Xfm,j(0,t)=Xfm,jin(t),Tf(0,t)=Tfin(t), ∂Ts∂xx=0=0,∂Ts∂xx=L=0. given.

[0043] Consequently, the above regarding the Fig. 4 and Fig. The 5 illustrated methods 400 and 500 provide a method for a power engine that contains a catalyst.The procedure comprises determining the catalyst activity based on an error between a predicted exhaust gas sensor output and a measured exhaust gas sensor output; applying the catalyst activity and the concentrations of two or fewer grouped intake exhaust gas types to a catalyst model containing a set of time- and space-averaged mass balance and energy balance equations of a fluid phase and an intermediate layer of the catalyst to determine a total oxygen storage capacity and a partial oxidation state of the catalyst; maintaining a target air-fuel ratio based on the total oxygen storage capacity and the partial oxidation state of the catalyst; and indicating catalyst degradation if the catalyst activity or the total oxygen storage capacity is less than a threshold value.In this way, each group of exhaust gas types can be entered into a catalyst model that simultaneously averages the catalyst dynamics over time and space, such as temperature, composition, etc. Based on the catalyst model, the air-fuel ratio can be controlled and catalyst degradation can be predicted.

[0044] While the with regard to the Fig. 4 and Fig. In the embodiment described in section 5, where the mass balance is calculated for two or fewer grouped exhaust gas types comprising CO, HC, NOx, H2, H2O, O2, and CO2, the computation speed is consequently increased, and cold-start emissions are accurately predicted. The grouped types can be, for example, divided into oxidizing agents (e.g., O2 and NOx) and reducing agents (e.g., HC, CO, and H2).

[0045] It is clear that the configurations and methods disclosed herein are exemplary and that these specific embodiments are not to be considered limiting, as numerous variations are possible. The above technology can be applied, for example, to V-6, R-4 (I-4), R-6 (I-6), V-12, Boxer-4, and other types of power engines. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0046] The following claims specifically describe certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element, "a first" element, or its equivalent. Such claims should be understood as including one or more such elements and neither requiring nor excluding two or more such elements. Further combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by presenting new claims in this or a related application.Such claims, whether their scope is broader than, narrower than, equal to, or different from the scope of the original claims, are also considered to be included in the subject matter of the present disclosure.

Claims

[1] Engine exhaust method comprising the following: Adjusting a fuel injection quantity based on a partial oxidation state of a catalyst, wherein the partial oxidation state is based on the reaction rates of two or fewer groupings of exhaust gas types in a catalyst and a one-dimensional model of space and time averaged mass balance and energy balance equations for a fluid phase and an intermediate layer of the catalyst. [2] Method according to claim 1, wherein the groupings of exhaust gas types further comprise the grouping of the chemical exhaust gas types into an oxidizing agent group and a reducing agent group. [3] Method according to claim 2, wherein a single value of the diffusivity is used in the mass balance equations for both the oxidizing agent group and the reducing agent group. [4] Method according to claim 3, wherein the adjustment of the fuel injection quantity is based on the partial oxidation state of a catalyst during the cold start of a power engine (10). [5] The method of claim 1, further comprising determining an estimated total oxygen storage capacity and adjusting the fuel injection quantity based on the estimated total oxygen storage capacity, wherein the estimated total oxygen storage capacity is maintained at 50%. [6] The method of claim 5, further comprising indicating the deterioration of the catalyst if the total oxygen storage capacity is below a threshold capacity or if the specified catalyst activity is below a calibrated threshold. [7] Method according to claim 5, wherein determining the total oxygen storage capacity and the partial oxidation state further comprises determining the outlet concentrations of the grouped species based on inlet concentrations of the grouped species, wherein the inlet concentrations of the grouped species are determined based on the air mass, the temperature, the air / fuel ratio of the exhaust gas and the engine speed. [8] Method according to claim 1, wherein the reaction rates of the grouped exhaust gas types and the partial oxidation state are further based on a specific catalyst enhancement. [9] Method according to claim 1, wherein the fuel injection quantity is further adjusted based on an input from an oxygen sensor upstream of the catalyst and an oxygen sensor downstream of the catalyst, and wherein the fuel injection quantity is adjusted to maintain the partial oxidation state at a threshold level calibrated based on the engine load and engine temperature. [10] System comprising the following: a catalyst positioned in an exhaust system of the engine (10); a controller (12) containing instructions to: to determine a catalyst activity, a total oxygen storage capacity, and a partial oxidation state of the catalyst based on a catalyst model that tracks a change in the concentration of two or fewer groupings of the species through the catalyst using a one-dimensional model of space- and time-averaged mass balance and energy balance equations for a fluid phase and an intermediate layer of the catalyst; and to indicate the deterioration of the catalyst if the catalyst activity or the total oxygen storage capacity is below a threshold value. [11] System according to claim 10, wherein the total oxygen storage capacity is a function of an estimated error between the exhaust gas sensor voltage predicted by the model and the measured exhaust gas sensor voltage. [12] System according to claim 11, wherein catalyst enhancement is based on an upstream air / fuel ratio, a downstream air / fuel ratio, an air mass and a temperature. [13] System according to claim 10, wherein the controller (12) further contains instructions to adjust a fuel injection quantity into the engine (10) if the partial oxidation state is outside a threshold range. [14] System according to claim 10, wherein the controller (12) further contains non-volatile instructions stored in memory to determine the inlet concentration of the grouped species based on an air mass, a temperature, an air / fuel ratio of the exhaust gas and an engine speed, wherein the grouped inlet species further comprise an oxidizing agent group and a reducing agent group, wherein the oxidizing agent group further comprises NOx and / or O2 and / or H2O and / or CO2 and the reducing agent group further comprises CO and / or HC and / or H2 and / or H2O and wherein the catalyst is a three-way catalyst. [15] Method for a power engine (10) containing a catalyst, the method comprising the following. Determining catalyst activity based on an error between a predicted exhaust gas sensor output and a measured exhaust gas sensor output; applying the catalyst activity and the concentrations of two or fewer groupings of intake exhaust gas types to a catalyst model that includes a one-dimensional model of space- and time-averaged mass balances and energy balances of a fluid phase and an intermediate layer of the catalyst to determine an overall oxygen storage capacity and a partial oxidation state of the catalyst; Maintaining a target air-fuel ratio based on the total oxygen storage capacity and the partial oxidation state of the catalyst; and Indicates a deterioration of the catalyst if the catalyst activity or the total oxygen storage capacity is less than a threshold value. [16] Method according to claim 15, wherein the partial oxidation state of the catalyst further comprises the partial oxidation state of the cerium dioxide in the catalyst, which is determined based on a change in the oxygen concentration by the catalyst. [17] Method according to claim 15, wherein the inlet exhaust gas types comprise CO, HC, NOx, H2, H2O, O2 and CO2 and the method further comprises combining the inlet exhaust gas types into an oxidizing agent group and a reducing agent group. [18] Method according to claim 15, wherein an air-fuel target ratio is further maintained based on the inputs from an oxygen sensor upstream of the catalyst and an oxygen sensor downstream of the catalyst. [19] Method according to claim 15, wherein the catalyst activity indicates the total oxygen storage capacity of the catalyst.

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