Ammonia Leak Detection Method, Device, Readable Storage Medium and Ammonia Leak Detection System

Abstract

The present application provides an ammonia leakage detection method, device, readable storage medium and ammonia leakage detection system. The method includes: obtaining the NH3 mass flow rate upstream of the first SCR, and determining the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR; determining the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor; determining the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR; determining the maximum ammonia storage of the second SCR according to the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR, and determining that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage of the second SCR. This solution realizes the real-time detection of NH3 leakage.

Description

Technical Field

[0001] The present application relates to the field of ammonia leakage detection, and in particular, to an ammonia leakage detection method, device, readable storage medium and ammonia leakage detection system. Background Art

[0002] In the post-treatment of diesel engines, the SCR (Selective Catalytic Reducer) is responsible for reducing environmentally harmful NOx in the exhaust gas to N2. Currently, the control scheme based on NOx sensors mainly relies on capturing the reverse drag condition window to determine whether ammonia leakage occurs. This scheme partially solves the ammonia leakage problem, but there are still problems such as being unable to judge in real time whether ammonia leakage occurs and unable to calculate the ammonia leakage amount in real time; it is not conducive to calculating the urea demand injection amount more reasonably and not conducive to further improving the SCR efficiency. Summary of the Invention

[0003] The main object of the present application is to provide an ammonia leakage detection method, device, readable storage medium and ammonia leakage detection system to solve the problem that the existing ammonia leakage detection scheme cannot judge in real time whether ammonia leakage occurs.

[0004] To achieve the above object, according to one aspect of the present application, an ammonia leakage detection method is provided, including: obtaining the NH3 mass flow rate upstream of the first SCR, and determining the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR; determining the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor, where the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR; determining the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR; determining the maximum ammonia storage amount of the second SCR according to the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR, and determining that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage amount of the second SCR. By installing an NH3 sensor on the pipeline between the first SCR and the second SCR, then determining the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR, and then calculating the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR, and finally determining that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage amount of the second SCR.

[0005] Optionally, the method further includes: obtaining the NOx mass flow rate downstream of the first SCR; determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR, so as to accurately determine the mass of NH3 oxidized in the second SCR.

[0006] Optionally, after determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR, the method further includes: determining the ammonia leakage amount according to the mass of NH3 oxidized in the second SCR, the ammonia storage model value of the second SCR, and the NH3 mass flow rate detected by the NH3 sensor, so as to accurately determine the ammonia leakage amount.

[0007] Optionally, determining the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR includes: constructing a first SCR kinetic model; determining the NH3 mass flow rate downstream of the first SCR according to the first SCR kinetic model, where the input signal of the first SCR kinetic model includes the NH3 mass flow rate upstream of the first SCR, and the output signal of the first SCR kinetic model includes the NH3 mass flow rate downstream of the first SCR. Accurately determining the NH3 mass flow rate downstream of the first SCR is achieved by constructing the first SCR kinetic model.

[0008] Optionally, determining the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor includes: constructing an adaptive control model; determining the NH3 mass flow rate upstream of the second SCR according to the adaptive control model, where the input signal of the adaptive control model includes the output signal of the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor, and the output signal of the adaptive control model includes the NH3 mass flow rate upstream of the second SCR. By using the self-adjustment mechanism of the adaptive model, accurately determining the NH3 mass flow rate upstream of the second SCR is achieved.

[0009] Optionally, the method further includes: calculating a correction coefficient by performing an operation on the NH3 mass flow rate downstream of the first SCR output by the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor using the adaptive control model; correcting the first SCR kinetic model using the correction coefficient to obtain a corrected first SCR kinetic model, and the difference between the NH3 mass flow rate downstream of the first SCR output by the corrected first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor is within a preset difference range. A correction coefficient is obtained based on the calculated NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the sensor downstream of the first SCR to correct the first SCR kinetic model, so that the difference between the NH3 mass flow rate downstream of the first SCR output by the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor is small and almost equal.

[0010] Optionally, determining the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR includes: constructing a second SCR kinetic model; determining the ammonia storage model value of the second SCR according to the second SCR kinetic model, the input signal of the second SCR kinetic model includes the output signal of the adaptive control model, and the output signal of the second SCR kinetic model includes the ammonia storage model value of the second SCR. The accurate determination of the ammonia storage model value of the second SCR is achieved by integrating the adaptive control model and the second SCR kinetic model.

[0011] According to another aspect of the present application, there is provided an ammonia leakage detection device, comprising: a processing unit configured to obtain the NH3 mass flow rate upstream of the first SCR and determine the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR; a first determination unit configured to determine the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor, wherein the first SCR is upstream of the second SCR and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR; a second determination unit configured to determine the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR; a third determination unit configured to determine the maximum ammonia storage of the second SCR according to the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR, and determine that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage of the second SCR. By installing an NH3 sensor on the pipeline between the first SCR and the second SCR, the first determination unit determines the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR, the second determination unit calculates the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR, and the third determination unit determines that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage of the second SCR.

[0012] According to another aspect of the present application, there is provided a computer-readable storage medium, which includes a stored program, wherein when the program runs, it controls the device where the computer-readable storage medium is located to execute any one of the ammonia leakage detection methods.

[0013] According to still another aspect of the present application, there is provided an ammonia leakage detection system, comprising: a first SCR, a second SCR, an NH3 sensor and a controller, the controller is respectively in communication with the first SCR, the second SCR and the NH3 sensor, and the controller is configured to execute any one of the ammonia leakage detection methods. Description of the Drawings

[0014] The specification drawings forming a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0015] Figure 1 It shows a flowchart of the ammonia leakage detection method according to an embodiment of the present application;

[0016] Figure 2 Shows a schematic diagram of an ammonia leakage detection device according to an embodiment of the present application;

[0017] Figure 3 Shows a schematic diagram of an ammonia leakage detection system according to an embodiment of the present application;

[0018] Figure 4 Shows a schematic diagram of a specific ammonia leakage detection method according to an embodiment of the present application.

[0019] Among them, the above-mentioned drawings include the following reference numerals:

[0020] 10. Controller; 20. Engine; 30. ccDOC; 40. ccSCR; 50. DOC; 60. DPF; 70. First SCR; 80. Second SCR; 90. ASC; 100. First temperature sensor; 110. First gas concentration sensor; 120. Urea nozzle; 130. Second temperature sensor; 140. Gas mass flow sensor; 150. Third temperature sensor; 160. Second gas concentration sensor. Detailed implementation manners

[0021] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The following will describe the present application in detail with reference to the drawings and in combination with the embodiments.

[0022] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to describe the embodiments of the present application here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element can be directly on the other element, or there may also be intermediate elements. Moreover, in the specification and claims, when an element is described as "connected" to another element, the element can be "directly connected" to the other element, or "connected" to the other element through a third element.

[0025] For the convenience of description, some nouns or terms related to the embodiments of the present application are described below:

[0026] SCR: Selective Catalytic Reduction (SCR) is a treatment device for NOx in diesel vehicle exhaust emissions. Under the action of a catalyst, a reducing agent such as ammonia or urea is injected to reduce NOx in the exhaust gas to N2 and H2O.

[0027] NOx: NO and NO2 in vehicle exhaust.

[0028] Arrhenius equation: An empirical equation established by Arrhenius in Sweden for the relationship between the reaction rate constant of a chemical reaction and temperature.

[0029] Close Coupled Diesel Oxidation Catalyst (abbreviated as ccDOC): It is a type of oxidation catalyst. The function of the oxidation catalyst is to convert carbon monoxide and hydrocarbons in the engine exhaust into harmless water and carbon dioxide.

[0030] Diesel Oxidation Catalyst (abbreviated as DOC): The function of the oxidation catalyst is to convert carbon monoxide and hydrocarbons in the engine exhaust into harmless water and carbon dioxide.

[0031] Close Coupled Selectively Catalytic Reduction (abbreviated as ccSCR): It is a type of selective catalytic reduction device. The function of the selective catalytic reduction device is to selectively reduce NO and NO2 to N2 under the action of a catalyst, with almost no oxidation reaction of NH3 and O2, thereby improving the selectivity of N2 and reducing the consumption of NH3.

[0032] Diesel Particulate Filter (abbreviated as DPF): It is mainly used to capture particles in the exhaust gas to meet the requirements for the number of particle emissions.

[0033] According to an embodiment of the present application, an ammonia leakage detection method is provided.

[0034] Figure 1 is a flowchart of an ammonia leakage detection method according to an embodiment of the present application. As Figure 1 shown, the method includes the following steps:

[0035] Step S101, obtain the NH3 mass flow rate upstream of the first SCR, and determine the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR;

[0036] Step S102, determine the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor, where the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR;

[0037] Step S103, determine the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR;

[0038] Step S104, determine the maximum ammonia storage capacity of the second SCR according to the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR, and determine that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage capacity of the second SCR.

[0039] Specifically, the exhaust gas is generated by the combustion of fuel in the cylinder, and the main components are Soot carbon particles, NOx, moisture, N2, PN particles, CH particles, etc.

[0040] In the above solution, by installing an NH3 sensor on the pipeline between the first SCR and the second SCR, then determining the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR, and then calculating the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR, and finally determining that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage capacity of the second SCR.

[0041] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0042] In one embodiment of the present application, the above method further includes: obtaining the NOx mass flow rate downstream of the first SCR; determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR. The accurate determination of the mass of NH3 oxidized in the second SCR is realized.

[0043] Optionally, the NOx mass flow rate downstream of the first SCR is calculated by using a first SCR kinetic model for the NOx mass flow rate upstream of the first SCR obtained by a gas concentration sensor installed upstream of the first SCR.

[0044] Optionally, the NOx mass flow rate downstream of the first SCR is directly obtained by using a gas concentration sensor installed downstream of the first SCR.

[0045] Specifically, the specific implementation manner of determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR is: calculating the mass of NH3 oxidized in the second SCR according to a second SCR kinetic model constituted by the Arrhenius formula.

[0046] In one embodiment of the present application, after determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR, the above method further includes: determining the ammonia leakage amount according to the mass of NH3 oxidized in the second SCR, the ammonia storage model value of the second SCR, and the NH3 mass flow rate detected by the NH3 sensor.

[0047] Specifically, the specific determination manner of determining the ammonia leakage amount according to the mass of NH3 oxidized in the second SCR, the ammonia storage model value of the second SCR, and the NH3 mass flow rate detected by the NH3 sensor is: NH3 mass flow rate detected by the NH3 sensor - mass of NH3 oxidized in the second SCR - ammonia storage model value of the second SCR = ammonia leakage amount.

[0048] In one embodiment of the application, determining the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR includes: constructing a first SCR kinetic model; determining the NH3 mass flow rate downstream of the first SCR according to the first SCR kinetic model, wherein the input signal of the first SCR kinetic model includes the NH3 mass flow rate upstream of the first SCR, and the output signal of the first SCR kinetic model includes the NH3 mass flow rate downstream of the first SCR.

[0049] Specifically, the first SCR kinetic model is constructed based on the Arrhenius formula: k = Ae -Ea / RT It describes the relationship between the rate constant (k), temperature (T), and reaction activation energy Ea. A is a pre-exponential factor, R is the molar gas constant, and e is the base of the natural logarithm. More specifically, the temperature, reaction activation energy, and pre-exponential factor are made into a MAP, and then the reaction rate can be obtained by the ECU looking up the table.

[0050] Exemplarily, when constructing the first SCR kinetic model and the second SCR kinetic model, some or all of the following chemical reaction principles are considered:

[0051] NH3 adsorption, NH3 + Surf → NH 3surf ;

[0052] NH3 desorption, NH 3surf → NH3 + Surf;

[0053] Standard SCR, 4NH 3surf + 4NO + O2 → 4N2 + 6H2O;

[0054] Faster SCR, 4NH 3surf + 2NO + 2NO2 → 4N2 + 6H2O;

[0055] Slower SCR, 8NH 3surf + 6NO2 → 7N2 + 12H2O;

[0056] NH3 oxidation to form N2 (SCR), 4NH 3surf + 3O2 → 2N2 + 6H2O;

[0057] NO oxidation, NO + 1 / 2O2 → NO2;

[0058] NH3 oxidation to form N2, 4NH 3surf + 3O2 → 2N2 + 6H2O;

[0059] NH3 oxidation to form NO, 4NH 3surf + 5O2 → 4NO + 6H2O;

[0060] NH3 oxidation to form N2O, 2NH 3surf + 2O2 → N2O + 3H2O;

[0061] NO2 formation of N2O, 2NH 3surf + 2NO2 → 2N2O + N2 + 3H2O;

[0062] NO formation of N2O, 2NH 3surf + 2NO + O2 → 2N2O + N2 + 3H2O;

[0063] The oxidation of NH3 forms N2O, 2NH3 + 2O2 → N2O + 3H2O;

[0064] The oxidation of NH3 forms N2, 4NH3 + 3O2 → 2N2 + 6H2O;

[0065] The oxidation of NH3 forms NO, 4NH3 + 5O2 → 4NO + 6H2O.

[0066] More specifically, the chemical reaction principles considered by the first SCR kinetic model and the second SCR kinetic model are the same. Taking "NH3 adsorption" in the first SCR kinetic model as an example; the mass flow rate of NH3 injected into the first SCR can be known through the urea injection system. Then, according to the definition of chemical reaction rate, the generation rate of NH 3surf is r = k·dC(NH 3surf ;) / dt, where C(NH 3surf ;) represents the mass flow rate of NH3 adsorption, k represents the rate constant, and according to the Arrhenius formula k = Ae -Ea / RT , if factors such as temperature, catalyst, and activation energy that affect the rate constant k are calibrated on the test bench in the form of a MAP first, then the mass flow rate of NH3 adsorbed in the first SCR can be obtained. By analogy, the reaction rates of other reactants and products can be obtained, and thus the engineered first SCR kinetic model can be obtained.

[0067] In an embodiment of the present application, according to the mass flow rate of NH3 downstream of the first SCR and the mass flow rate of NH3 detected by the NH3 sensor, the mass flow rate of NH3 upstream of the second SCR is determined, including: constructing an adaptive control model; determining the mass flow rate of NH3 upstream of the second SCR according to the adaptive control model, where the input signal of the adaptive control model includes the output signal of the first SCR kinetic model and the mass flow rate of NH3 detected by the NH3 sensor, and the output signal of the adaptive control model includes the mass flow rate of NH3 upstream of the second SCR. That is, the mass flow rate of NH3 downstream of the first SCR and the mass flow rate of NH3 detected by the NH3 sensor are calculated by using a pre-constructed adaptive control model to obtain the mass flow rate of NH3 upstream of the second SCR. The self-adjusting mechanism of the adaptive model is used to accurately determine the mass flow rate of NH3 upstream of the second SCR.

[0068] More specifically, an information fusion scheme based on the "Kalman filter" can be adopted to construct an adaptive control model. The basic idea is to find a weight factor to construct a confidence function between the first SCR downstream NH3 mass flow output by the first SCR dynamic model and the NH3 mass flow detected by the NH3 sensor, so as to obtain a more reliable NH3 mass flow value, that is, to obtain the accurate "NH3 mass flow upstream of the second SCR" input into the second SCR dynamic model. This solution does not limit the specific structure of the adaptive control model. Those skilled in the art can make selections according to the actual situation without departing from the purpose of this application.

[0069] In an embodiment of this application, the above method further includes: using the above adaptive control model to calculate the NH3 mass flow downstream of the first SCR output by the first SCR dynamic model and the NH3 mass flow detected by the NH3 sensor to obtain a correction coefficient; using the above correction coefficient to correct the first SCR dynamic model to obtain a corrected first SCR dynamic model, and the difference between the NH3 mass flow downstream of the first SCR output by the corrected first SCR dynamic model and the NH3 mass flow detected by the NH3 sensor is within a preset difference range. That is, a correction coefficient is obtained based on the calculated NH3 mass flow downstream of the first SCR and the NH3 mass flow downstream of the first SCR detected by the sensor to correct the first SCR dynamic model, so that the difference between the NH3 mass flow downstream of the first SCR output by the first SCR dynamic model and the NH3 mass flow detected by the NH3 sensor is small and almost equal.

[0070] Specifically, a correction coefficient is obtained through feedback control based on the difference between the NH3 mass flow downstream of the first SCR output by the first SCR dynamic model and the NH3 mass flow detected by the NH3 sensor, and the relevant parameters in the first SCR dynamic model are corrected using the correction coefficient. Here, the feedback control selects adaptive control mainly to obtain a more accurate NH3 mass flow through information fusion of the NH3 mass flow downstream of the first SCR output by the first SCR dynamic model and the NH3 mass flow detected by the NH3 sensor under the current engine working condition, and accordingly correct the first SCR dynamic model to make the difference between the output value of the first SCR dynamic model and the value obtained through adaptive control smaller.

[0071] Among them, the relevant parameters include the pre-exponential factor and reaction activation energy of each chemical reaction. The relevant parameters are calibrated in advance and corrected according to the engine working condition during subsequent vehicle operation to approximate the real chemical reaction.

[0072] In an embodiment of the present application, determining the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR as described above includes: constructing a second SCR kinetic model; determining the ammonia storage model value of the second SCR according to the second SCR kinetic model, the input signal of the second SCR kinetic model includes the output signal of the adaptive control model, and the output signal of the second SCR kinetic model includes the ammonia storage model value of the second SCR.

[0073] Specifically, the second SCR kinetic model is constructed according to the Arrhenius equation: k = Ae -Ea / RT It describes the relationship between the rate constant (k), temperature (T), and reaction activation energy Ea. A is a pre-exponential factor, R is the molar gas constant, and e is the base of the natural logarithm.

[0074] In a specific embodiment of the present application, the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR are input into the second SCR kinetic model, and the output is the mass of NH3 oxidized.

[0075] The embodiment of the present application also provides an ammonia leakage detection device. It should be noted that the ammonia leakage detection device of the embodiment of the present application can be used to execute the ammonia leakage detection method provided by the embodiment of the present application. The ammonia leakage detection device provided by the embodiment of the present application is introduced below.

[0076] Figure 2 is a schematic diagram of the ammonia leakage detection device according to the embodiment of the present application. As Figure 2 shown, the device includes:

[0077] A processing unit 21, configured to obtain the NH3 mass flow rate upstream of the first SCR, and determine the NH3 mass flow rate downstream of the first SCR according to the NH3 mass flow rate upstream of the first SCR;

[0078] A first determination unit 22, configured to determine the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor, where the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR;

[0079] A second determination unit 23, configured to determine the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR;

[0080] A third determination unit 24, configured to determine a maximum ammonia storage amount of the second SCR according to a temperature value upstream of the second SCR and an exhaust gas mass flow rate flowing through the first SCR, and determine that there is NH3 leakage downstream of the second SCR when a modeled ammonia storage amount of the second SCR is greater than the maximum ammonia storage amount of the second SCR.

[0081] Specifically, the exhaust gas is generated by fuel combustion in a cylinder, and the main components include Soot carbon particles, NOx, moisture, N2, PN particles, CH particles, etc.

[0082] In the above solution, by installing an NH3 sensor on the pipeline between the first SCR and the second SCR, the first determination unit determines the NH3 mass flow rate upstream of the second SCR according to the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR. The second determination unit calculates a modeled ammonia storage amount of the second SCR according to the NH3 mass flow rate upstream of the second SCR. The third determination unit determines that there is NH3 leakage downstream of the second SCR when the modeled ammonia storage amount of the second SCR is greater than the maximum ammonia storage amount of the second SCR.

[0083] In an embodiment of the present application, the above device further includes an acquisition unit and a fourth determination unit. The acquisition unit is configured to acquire the NOx mass flow rate downstream of the first SCR. The fourth determination unit is configured to determine the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR.

[0084] Specifically, the specific implementation manner of determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR is: calculating the mass of NH3 oxidized in the second SCR according to a second SCR kinetic model constituted by the Arrhenius formula.

[0085] In an embodiment, the above device further includes a fifth determination unit. The fifth determination unit is configured to determine an ammonia leakage amount according to the mass of NH3 oxidized in the second SCR, the modeled ammonia storage amount of the second SCR, and the NH3 mass flow rate detected by the NH3 sensor after determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR.

[0086] Specifically, the specific determination method for determining the ammonia leakage amount based on the mass of NH3 oxidized in the second SCR, the ammonia storage model value of the second SCR, and the NH3 mass flow rate detected by the NH3 sensor is: NH3 mass flow rate detected by the NH3 sensor - mass of NH3 oxidized in the second SCR - ammonia storage model value of the second SCR = ammonia leakage amount.

[0087] In an embodiment of the present application, the processing unit includes a first construction module and a first determination module. The first construction module is used to construct a first SCR kinetic model; the first determination module is used to determine the NH3 mass flow rate downstream of the first SCR according to the above first SCR kinetic model. Among them, the input signal of the first SCR kinetic model includes the NH3 mass flow rate upstream of the first SCR, and the output signal of the first SCR kinetic model includes the NH3 mass flow rate downstream of the first SCR.

[0088] In an embodiment of the present application, the first determination unit includes a second construction module and a second determination module. The second construction module is used to construct an adaptive control model; the second determination module is used to determine the NH3 mass flow rate upstream of the second SCR according to the above adaptive control model. Among them, the input signal of the adaptive control model includes the output signal of the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor, and the output signal of the adaptive control model includes the NH3 mass flow rate upstream of the second SCR. That is, the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor are operated by using the pre-constructed adaptive control model to obtain the NH3 mass flow rate upstream of the second SCR.

[0089] In an embodiment of the present application, the above device further includes an operation unit and a correction unit. The operation unit is used to operate the NH3 mass flow rate downstream of the first SCR output by the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor by using the above adaptive control model to obtain a correction coefficient; the correction unit is used to correct the first SCR kinetic model by using the above correction coefficient to obtain a corrected first SCR kinetic model, and the difference between the NH3 mass flow rate downstream of the first SCR output by the corrected first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor is within a preset difference range. That is, the first SCR kinetic model is corrected according to the calculated NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate downstream of the first SCR detected by the sensor, so that the difference between the NH3 mass flow rate downstream of the first SCR output by the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor is small and almost equal.

[0090] In one embodiment of the present application, the second determination unit includes a third construction module and a third determination module. The third construction module is used to construct a second SCR kinetic model; the third determination module is used to determine the ammonia storage model value of the second SCR according to the second SCR kinetic model. The input signal of the second SCR kinetic model includes the output signal of the adaptive control model, and the output signal of the second SCR kinetic model includes the ammonia storage model value of the second SCR.

[0091] The ammonia leakage detection device includes a processor and a memory. The processing unit, the first determination unit, the second determination unit, the third determination unit, etc. are all stored in the memory as program units, and the processor executes the program units stored in the memory to implement corresponding functions.

[0092] The processor contains a kernel, and the kernel retrieves the corresponding program units from the memory. One or more kernels can be set, and real-time detection of ammonia leakage is achieved by adjusting the kernel parameters.

[0093] The memory may include non-permanent memory in a computer-readable medium, forms such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one storage chip.

[0094] An embodiment of the present invention provides a computer-readable storage medium. The computer-readable storage medium includes a stored program. When the program runs, it controls the device where the computer-readable storage medium is located to execute the ammonia leakage detection method.

[0095] An embodiment of the present invention provides a processor. The processor is used to run a program. When the program runs, it executes the ammonia leakage detection method.

[0096] An embodiment of the present invention provides a computer-readable storage medium. The computer-readable storage medium includes a stored program. When the program runs, it controls the device where the computer-readable storage medium is located to execute any one of the above ammonia leakage detection methods.

[0097] An embodiment of the present invention provides an ammonia leakage detection system, including: as Figure 3As shown, a first SCR 70, a second SCR 80, an NH3 sensor, and a controller 10. The controller 10 communicates with the first SCR 70, the second SCR 80, and the NH3 sensor respectively. The controller 10 is configured to execute any one of the above ammonia leakage detection methods. Applying this system, by installing an NH3 sensor on the pipeline between the first SCR 70 and the second SCR 80, and then determining the NH3 mass flow rate upstream of the second SCR 80 based on the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR 70. Furthermore, the ammonia storage model value of the second SCR 80 is calculated based on the NH3 mass flow rate upstream of the second SCR 80. Finally, when the ammonia storage model value of the second SCR 80 is greater than the maximum ammonia storage value of the second SCR 80, it is determined that there is NH3 leakage downstream of the second SCR 80.

[0098] An embodiment of the present invention provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements at least the following steps:

[0099] Step S101: Obtain the NH3 mass flow rate upstream of the first SCR, and determine the NH3 mass flow rate downstream of the first SCR based on the NH3 mass flow rate upstream of the first SCR;

[0100] Step S102: Determine the NH3 mass flow rate upstream of the second SCR based on the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor. Here, the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR;

[0101] Step S103: Determine the ammonia storage model value of the second SCR based on the NH3 mass flow rate upstream of the second SCR;

[0102] Step S104: Determine the maximum ammonia storage value of the second SCR based on the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR. And when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage value of the second SCR, it is determined that there is NH3 leakage downstream of the second SCR.

[0103] The device in this article can be a server, a PC, a PAD, a mobile phone, etc.

[0104] The present application also provides a computer program product, which is suitable for executing a program initialized with at least the following method steps when executed on a data processing device:

[0105] Step S101: Obtain the NH3 mass flow rate upstream of the first SCR, and determine the NH3 mass flow rate downstream of the first SCR based on the NH3 mass flow rate upstream of the first SCR as described above.

[0106] Step S102: Determine the NH3 mass flow rate upstream of the second SCR based on the NH3 mass flow rate downstream of the first SCR and the NH3 mass flow rate detected by the NH3 sensor. Here, the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR.

[0107] Step S103: Determine the ammonia storage model value of the second SCR based on the NH3 mass flow rate upstream of the second SCR as described above.

[0108] Step S104: Determine the maximum ammonia storage capacity of the second SCR based on the temperature value upstream of the second SCR and the mass flow rate of the exhaust gas flowing through the first SCR. And when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage capacity of the second SCR, it is determined that there is NH3 leakage downstream of the second SCR.

[0109] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0110] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0111] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction means that implements the function specified in one or more of the blocks and / or processes. Figure 1 in one or more of the processes and / or blocks Figure 1 specified in one or more of the blocks and / or processes.

[0112] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the function specified in one or more of the processes and / or blocks. Figure 1 in one or more of the processes and / or blocks Figure 1 specified in one or more of the blocks and / or processes.

[0113] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0114] The memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM) and / or non-volatile memory such as read only memory (ROM) or flash memory. Memory is an example of computer-readable media.

[0115] Computer-readable media includes both permanent and non-permanent, removable and non-removable media implemented by any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory media such as modulated data signals and carrier waves.

[0116] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, commodity or device comprising a series of elements not only includes those elements but also other elements not expressly listed, or elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, commodity or device comprising the element.

[0117] To enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution and technical effects of the present application will be described below in conjunction with specific embodiments.

[0118] Embodiment

[0119] This embodiment relates to a specific ammonia leakage detection method, as Figure 3 and Figure 4 shown,

[0120] As Figure 3 shown, the ammonia leakage detection system includes a controller 10, an engine 20, a ccDOC 30, a ccSCR 40, a DOC 50, a DPF 60, a first SCR 70, a second SCR 80, an ASC 90, a first temperature sensor 100, a first gas concentration sensor 110, a urea nozzle 120, a second temperature sensor 130, a gas mass flow sensor 140, a third temperature sensor 150 and a second gas concentration sensor 160. The first temperature sensor 100 is used to detect the temperature downstream of the DPF 60, the first gas concentration sensor 110 is used to detect the concentration of NOx upstream of the first SCR 70, the second temperature sensor 130 is used to detect the temperature downstream of the first SCR 70, the gas mass flow sensor 140 is used to detect the mass flow of NH3 downstream of the first SCR, and a third temperature sensor 150 and a second gas concentration sensor 160 are also installed downstream of the ASC. The second gas concentration sensor 160 is used to detect the concentration of NOx downstream of the ASC 90.

[0121] As Figure 4As shown in the figure, it includes a first SCR kinetic model, an adaptive control model, and a second SCR kinetic model. The input signals of the first SCR kinetic model include NOx upstream of the first SCR, NH3 upstream of the first SCR, the temperature upstream of the first SCR, and the exhaust gas mass flow rate. The output signals of the first SCR kinetic model include NOx downstream of the first SCR, the NH3 mass flow rate downstream of the first SCR, the temperature upstream of the first SCR, and the exhaust gas mass flow rate. The input signals of the NH3 mass flow rate adaptive control model downstream of the first SCR include the NH3 mass flow rate downstream of the first SCR, the temperature upstream of the first SCR, the exhaust gas mass flow rate, and the NH3 mass flow rate detected by the sensor. The output signals of the NH3 mass flow rate adaptive control model downstream of the first SCR include the NH3 mass flow rate upstream of the second SCR, the temperature upstream of the second SCR, and the exhaust gas mass flow rate. The input signals of the second SCR kinetic model include the NH3 mass flow rate upstream of the second SCR, the temperature upstream of the second SCR, the exhaust gas mass flow rate, and NOx downstream of the first SCR. The output signals of the second SCR kinetic model include the ammonia storage model value of the second SCR and the amount of oxidized NH3 in the second SCR. Further, the ammonia leakage amount is calculated based on the ammonia storage model value of the second SCR, the amount of oxidized NH3 in the second SCR, and the NOx mass flow rate downstream of the second SCR.

[0122] Specifically, a first gas concentration sensor 110 is installed upstream of the first SCR. The first gas concentration sensor 110 is used to detect the NOx mass flow rate upstream of the first SCR. Then, the NOx mass flow rate downstream of the first SCR is determined according to the first SCR kinetic model. The NOx mass flow rate downstream of the first SCR is a parameter input into the second SCR kinetic model.

[0123] Among them, the ammonia storage model value of the second SCR is obtained by integrating the ammonia storage over a period of time.

[0124] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0125] 1), The ammonia leakage detection method of the present application installs an NH3 sensor on the pipeline between the first SCR and the second SCR. Then, the NH3 mass flow rate upstream of the second SCR is determined according to the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR. Furthermore, the ammonia storage model value of the second SCR is calculated based on the NH3 mass flow rate upstream of the second SCR. Finally, when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage value of the second SCR, it is determined that there is NH3 leakage downstream of the second SCR.

[0126] 2) The ammonia leakage detection device of the present application installs an NH3 sensor on the pipeline between the first SCR and the second SCR. The first determination unit determines the NH3 mass flow rate upstream of the second SCR based on the NH3 mass flow rate detected by the NH3 sensor and the NH3 mass flow rate downstream of the first SCR. The second determination unit calculates the ammonia storage model value of the second SCR based on the NH3 mass flow rate upstream of the second SCR. The third determination unit determines that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage of the second SCR.

[0127] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. An ammonia leakage detection method, characterized in that, Including: Obtain the NH3 mass flow rate upstream of the first SCR, construct a first SCR kinetic model, and determine the NH3 mass flow rate downstream of the first SCR according to the first SCR kinetic model, wherein the input signal of the first SCR kinetic model includes the NH3 mass flow rate upstream of the first SCR, and the output signal of the first SCR kinetic model includes the NH3 mass flow rate downstream of the first SCR; Construct an adaptive control model, and determine the NH3 mass flow rate upstream of the second SCR according to the adaptive control model, wherein the input signal of the adaptive control model includes the output signal of the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor, and the output signal of the adaptive control model includes the NH3 mass flow rate upstream of the second SCR, wherein the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR; Determine the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR; Determine the maximum ammonia storage capacity of the second SCR according to the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR, and determine that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage capacity of the second SCR.

2. The method according to claim 1, wherein The method further includes: Obtain the NOx mass flow rate downstream of the first SCR; Determine the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR.

3. The method according to claim 2, wherein After determining the mass of NH3 oxidized in the second SCR according to the NOx mass flow rate downstream of the first SCR and the NH3 mass flow rate upstream of the second SCR, the method further includes: Determine the ammonia leakage amount according to the mass of NH3 oxidized in the second SCR, the ammonia storage model value of the second SCR, and the NH3 mass flow rate detected by the NH3 sensor.

4. The method according to claim 1, characterized in that, The method further includes: Use the adaptive control model to calculate the NH3 mass flow rate downstream of the first SCR output by the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor to obtain a correction coefficient; Use the correction coefficient to correct the first SCR kinetic model to obtain a corrected first SCR kinetic model, and the difference between the NH3 mass flow rate downstream of the first SCR output by the corrected first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor is within a preset difference range.

5. The method according to claim 1, characterized in that, Determining the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR includes: Construct a second SCR kinetic model; Determine the ammonia storage model value of the second SCR according to the second SCR kinetic model, where the input signal of the second SCR kinetic model includes the output signal of the adaptive control model, and the output signal of the second SCR kinetic model includes the ammonia storage model value of the second SCR.

6. An ammonia leakage detection device, characterized in that, Comprising: A processing unit, configured to obtain the NH3 mass flow rate upstream of the first SCR, construct a first SCR kinetic model, and determine the NH3 mass flow rate downstream of the first SCR according to the first SCR kinetic model, where the input signal of the first SCR kinetic model includes the NH3 mass flow rate upstream of the first SCR, and the output signal of the first SCR kinetic model includes the NH3 mass flow rate downstream of the first SCR; A first determination unit, configured to construct an adaptive control model and determine the NH3 mass flow rate upstream of the second SCR according to the adaptive control model, where the input signal of the adaptive control model includes the output signal of the first SCR kinetic model and the NH3 mass flow rate detected by the NH3 sensor, and the output signal of the adaptive control model includes the NH3 mass flow rate upstream of the second SCR, where the first SCR is upstream of the second SCR, and the NH3 sensor is installed on the pipeline between the first SCR and the second SCR; A second determination unit, configured to determine the ammonia storage model value of the second SCR according to the NH3 mass flow rate upstream of the second SCR; A third determination unit, configured to determine the maximum ammonia storage capacity of the second SCR according to the temperature value upstream of the second SCR and the exhaust gas mass flow rate flowing through the first SCR, and determine that there is NH3 leakage downstream of the second SCR when the ammonia storage model value of the second SCR is greater than the maximum ammonia storage capacity of the second SCR.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, where, when the program runs, it controls the device where the computer-readable storage medium is located to execute the ammonia leakage detection method according to any one of claims 1 to 5.

8. An ammonia leakage detection system, characterized in that, Comprising: A first SCR, a second SCR, an NH3 sensor, and a controller, where the controller communicates with the first SCR, the second SCR, and the NH3 sensor respectively, and the controller is configured to execute the ammonia leakage detection method according to any one of claims 1 to 5.

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