Ammonia leakage detection method and device, electronic equipment and storage medium
By combining the operating parameters of the urea injection system, nitrogen oxide sensor, and catalyst with the deviation between ammonia storage and nitrogen oxide conversion efficiency ratio, high-precision ammonia leak detection without relying on ammonia sensors was achieved. This solved the problems of high cost and insufficient reliability of existing ammonia leak detection technologies, and improved the accuracy and reliability of detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FAW JIEFANG AUTOMOTIVE CO
- Filing Date
- 2026-01-28
- Publication Date
- 2026-04-21
AI Technical Summary
In existing technologies, ammonia leak detection relies on ammonia sensors, which are costly and lack accuracy and reliability at low concentrations. They are also susceptible to cross-interference from other components in the exhaust gas. There is an urgent need for a high-precision and high-reliability ammonia leak detection method that does not rely on ammonia sensors.
By analyzing the operating parameters of the urea injection system, nitrogen oxide sensor, and catalyst, it is determined whether the ammonia leak detection conditions are met. Combining the current urea injection volume and nitrogen oxide content, the ammonia storage capacity and nitrogen oxide conversion efficiency ratio deviation of the catalyst are determined. A dual judgment criterion is used to determine whether an ammonia leak has occurred.
High-precision and high-reliability ammonia leak detection was achieved without relying on ammonia sensors, reducing false alarm rates and improving detection accuracy and reliability.
Smart Images
Figure CN121897448A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automobile manufacturing technology, and in particular to an ammonia leak detection method, device, electronic equipment, and storage medium. Background Technology
[0002] In the treatment of diesel engine exhaust pollutants, a closed-loop control system based on exhaust nitrogen oxide sensors precisely injects urea into the exhaust pipe at levels matched to the engine's operating conditions. Urea decomposes into ammonia at high temperatures, which then reacts with nitrogen oxides in the catalytic converter through a catalytic reduction reaction, ultimately producing harmless nitrogen and water. However, if the catalytic converter's ammonia adsorption and storage capacity decreases or the urea injection strategy is inaccurate, excessive ammonia can penetrate the catalytic converter, causing ammonia leakage. Ammonia leakage not only causes environmental pollution and ammonia waste but can also form secondary particulate matter. Therefore, ammonia leakage detection is a crucial issue in the field of automotive exhaust treatment.
[0003] Ammonia sensors that directly detect ammonia leaks are expensive, have response delays, and lack accuracy and reliability at low concentrations. They are also susceptible to cross-interference from other components in the exhaust gas. There is an urgent need for a high-precision, high-reliability ammonia leak detection method that does not rely on ammonia sensors. Summary of the Invention
[0004] This invention provides an ammonia leak detection method, apparatus, electronic device, and storage medium to achieve high-precision and high-reliability ammonia leak detection without relying on an ammonia sensor.
[0005] In a first aspect, embodiments of the present invention provide an ammonia leak detection method, the method comprising:
[0006] Determine whether the ammonia leak detection conditions are met based on at least one of the operating parameters of the urea injection system, nitrogen and oxygen sensor, and catalyst.
[0007] When the ammonia leak detection conditions are met, the current ammonia storage of the catalyst is determined based on the current urea injection volume and the upstream nitrogen oxide content, and the nitrogen oxide conversion efficiency ratio deviation within a preset time period is determined based on the upstream nitrogen oxide content and the downstream nitrogen oxide content.
[0008] Based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio, determine whether an ammonia leak has occurred.
[0009] Secondly, embodiments of the present invention also provide an ammonia leak detection device, the device comprising:
[0010] The ammonia leak detection condition judgment module is used to determine whether the ammonia leak detection conditions are met based on at least one of the operating parameters of the urea injection system, the nitrogen and oxygen sensor, and the catalyst.
[0011] The module for calculating the current ammonia storage and nitrogen oxide conversion efficiency ratio deviation is used to determine the current ammonia storage of the catalyst based on the current urea injection volume and the upstream nitrogen oxide content when the ammonia leakage detection conditions are met, and to determine the nitrogen oxide conversion efficiency ratio deviation within a preset time period based on the upstream nitrogen oxide content and the downstream nitrogen oxide content.
[0012] The ammonia leak detection module is used to determine whether an ammonia leak has occurred based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio.
[0013] Thirdly, embodiments of the present invention also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the ammonia leak detection method as described in any of the embodiments of the present invention.
[0014] Fourthly, embodiments of the present invention also provide a storage medium for storing computer-executable instructions, which, when executed by a computer processor, are used to perform the ammonia leak detection method as described in any of the embodiments of the present invention.
[0015] The technical solution of this invention determines whether ammonia leak detection conditions are met by using at least one operating parameter of the urea injection system, a nitrogen oxide sensor, and the catalyst. When the ammonia leak detection conditions are met, the current ammonia storage level of the catalyst is determined based on the current urea injection rate and the upstream nitrogen oxide content. Furthermore, the nitrogen oxide conversion efficiency ratio deviation within a preset time period is determined based on the upstream and downstream nitrogen oxide content. Finally, based on the current ammonia storage level and the nitrogen oxide conversion efficiency ratio deviation, it is determined whether an ammonia leak has occurred. This technical solution does not rely on an additional ammonia sensor. By setting ammonia leak detection conditions, it ensures that ammonia leak detection is performed only under steady-state operating conditions with high diagnostic reliability, reducing the false alarm rate. Simultaneously, the combined diagnostic mechanism based on the current ammonia storage level and the nitrogen oxide conversion efficiency ratio deviation improves the accuracy and reliability of ammonia leak detection.
[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a flowchart of an ammonia leak detection method provided in Embodiment 1 of the present invention;
[0019] Figure 2 This is a flowchart of an ammonia leak detection method provided in Embodiment 2 of the present invention;
[0020] Figure 3 This is a schematic diagram of the structure of an ammonia leak detection device provided in Embodiment 3 of the present invention;
[0021] Figure 4 This is a schematic diagram of the structure of an electronic device provided in Embodiment 4 of the present invention. Detailed Implementation
[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices. In the embodiments of this application, certain software, components, models, and other existing industry solutions may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solutions of this application, and do not imply that the applicant has already used or necessarily used such solutions.
[0024] The acquisition, transmission, storage, use, and processing of data in this application all comply with the relevant provisions of national laws and regulations.
[0025] Example 1
[0026] Figure 1The flowchart of an ammonia leak detection method provided in Embodiment 1 of the present invention is applicable to the detection of ammonia leaks during automobile exhaust treatment. The method can be executed by an ammonia leak detection device, which can be implemented in hardware and / or software and can be configured in the vehicle control system.
[0027] like Figure 1 As shown, the method includes:
[0028] S110. Determine whether the ammonia leak detection conditions are met based on at least one of the operating parameters of the urea injection system, the nitrogen and oxygen sensor, and the catalyst.
[0029] The urea injection system injects urea into the exhaust pipe. Urea decomposes at high temperatures to produce ammonia, which then undergoes a catalytic reduction reaction with nitrogen oxides in the catalyst. The operating parameters of the urea injection system are used to determine its operational status, thereby eliminating insufficient urea injection and improving the accuracy of ammonia leak detection.
[0030] The nitrogen oxide (NOx) sensor includes an upstream NOx sensor and a downstream NOx sensor, respectively located upstream and downstream of the catalyst, to detect the NOx content upstream and downstream of the catalyst. The operating parameters of the NOx sensor include its own operating parameters and the signal output by the sensor. The operating parameters are used to determine the NOx sensor's operational status, thereby eliminating potential malfunctions. The output signal, representing the upstream and downstream NOx content, is used to determine whether the conditions indicate an ammonia leak.
[0031] A catalytic converter is used to catalytically reduce ammonia from urea decomposition with nitrogen oxides, thus treating exhaust gases. The operating parameters of the catalytic converter include its operational parameters and its nitrogen oxide conversion efficiency. The operational parameters are used to determine the catalytic converter's working status, thereby identifying and eliminating catalytic converter malfunctions. The nitrogen oxide conversion efficiency is used to assess whether the catalytic converter is in a reaction state that worsens emissions, thereby determining whether it meets the requirements for ammonia leakage conditions.
[0032] In this embodiment, the ammonia leak detection conditions are determined by using at least one of the operating parameters of the urea injection system, the nitrogen-oxygen sensor, and the catalyst. This eliminates interference from transient engine operating conditions and low-concentration signals on ammonia leak detection, ensuring that ammonia leak detection is performed only under highly reliable and stable operating conditions, thereby reducing the false alarm rate of ammonia leaks.
[0033] S120. When the ammonia leak detection conditions are met, determine the current ammonia storage of the catalyst based on the current urea injection volume and the upstream nitrogen oxide content, and determine the nitrogen oxide conversion efficiency ratio deviation within a preset time period based on the upstream nitrogen oxide content and the downstream nitrogen oxide content.
[0034] In this embodiment, when the ammonia leak detection conditions are met, a dual joint judgment mechanism based on the current ammonia storage level and the deviation of the nitrogen oxide conversion efficiency ratio is used to determine whether an ammonia leak has occurred. By judging the ammonia leak detection conditions, stringent ammonia leak detection enabling conditions are provided, improving the accuracy of ammonia leak detection. The dual joint judgment mechanism based on the current ammonia storage level and the deviation of the nitrogen oxide conversion efficiency ratio together ensures the accuracy of the ammonia leak diagnosis results.
[0035] The current urea injection rate can be obtained from the operating parameters of the urea injection system, indicating the urea content injected by the system. The upstream nitrogen oxide content can be obtained from the upstream nitrogen oxide sensor, indicating the current nitrogen oxide content upstream of the catalyst. This nitrogen oxide content can be expressed as nitrogen oxide concentration, in ppm or mg / m³. 3 .
[0036] Specifically, determining the current ammonia storage level of the catalyst based on the current urea injection rate and upstream nitrogen oxide content can include:
[0037] S11. Determine the ammonia generation amount based on the current urea injection rate;
[0038] S12. Determine the amount of ammonia required for the catalyst to consume the upstream nitrogen oxide content based on the upstream nitrogen oxide content;
[0039] S13. Determine the current ammonia storage level of the catalyst based on the ammonia production and ammonia consumption.
[0040] Based on the current urea injection rate, the amount of ammonia generated from the conversion of the current urea injection rate can be calculated. Specifically, according to the conversion law between urea and ammonia, the amount of ammonia generated is obtained by dividing the current urea injection rate by 5.4.
[0041] Based on the upstream nitrogen oxide content, the amount of ammonia required for the catalytic reduction reaction of the catalyst to consume nitrogen oxides can be calculated. Similarly, based on the stoichiometric relationship of the catalytic reduction reaction, the amount of ammonia consumed corresponding to the nitrogen oxide content can be calculated.
[0042] Understandably, ammonia generation represents the ammonia content after the urea injected by the urea injection system is converted, while ammonia consumption represents the ammonia content required for the catalytic reduction reaction in the catalyst. The difference between ammonia generation and ammonia consumption is the remaining ammonia content after the catalytic reduction reaction, which is also the current ammonia storage in the catalyst.
[0043] The current ammonia storage level directly reflects the saturation state of the catalyst carrier's adsorption capacity, and excessive current ammonia storage is a necessary condition for ammonia leakage.
[0044] The downstream nitrogen oxide content can be obtained through a downstream nitrogen oxide sensor to indicate the current nitrogen oxide content downstream of the catalyst. Similarly, the nitrogen oxide content here can be expressed as nitrogen oxide concentration. The nitrogen oxide conversion efficiency ratio deviation is defined as the ratio of the maximum to the average nitrogen oxide conversion efficiency of the catalyst within the detection window.
[0045] Specifically, based on the upstream and downstream nitrogen oxide content, the deviation in the nitrogen oxide conversion efficiency ratio within a preset time period is determined, including:
[0046] The nitrogen oxide conversion efficiency within the preset time period is determined based on the upstream and downstream nitrogen oxide contents within the preset time period.
[0047] The deviation of the nitrogen oxide conversion efficiency ratio is determined based on the maximum and average values of the nitrogen oxide conversion efficiency within a preset time period.
[0048] Specifically, a detection window period can be preset, for example, 10 minutes. Within the 10 minutes preceding the current moment, the upstream and downstream nitrogen oxide contents output by the upstream and downstream nitrogen oxide sensors are used to calculate the nitrogen oxide conversion efficiency at that specific moment, based on the corresponding upstream and downstream nitrogen oxide contents. A set of nitrogen oxide conversion efficiencies can be calculated for the detection window period. Specifically, the nitrogen oxide conversion efficiency can be calculated using the following formula: ,in, Indicates nitrogen oxide conversion efficiency. Indicates the downstream nitrogen oxide content, This indicates the upstream nitrogen oxide content.
[0049] Within the detection window period, the maximum value of a set of nitrogen oxide conversion efficiencies is determined, and the average value of the set of nitrogen oxide conversion efficiencies is calculated. The ratio of the maximum value to the average value is then taken as the nitrogen oxide conversion efficiency ratio deviation. Statistical analysis of historical ammonia leakage events shows that ammonia leakage causes a drop in catalyst activity from its peak; the more pronounced the abnormal drop from its peak, the greater the nitrogen oxide conversion efficiency ratio deviation.
[0050] Therefore, in this embodiment, the deviation of the nitrogen oxide conversion efficiency ratio is used as a sufficient condition for judging ammonia leakage. Together with the current ammonia storage level being a necessary condition for ammonia leakage, the two work together to corroborate each other and are indispensable, thus ensuring the accuracy of the ammonia leakage detection results.
[0051] S130. Based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio, determine whether an ammonia leak has occurred.
[0052] This embodiment reduces the false alarm rate of ammonia leak detection and ensures the accuracy of the detection results by setting two different criteria for ammonia leak detection.
[0053] Specifically, S130 may include:
[0054] If the current ammonia storage level is determined to be greater than or equal to the current ammonia storage level threshold, and the nitrogen oxide conversion efficiency ratio deviation is greater than or equal to the preset deviation threshold, then an ammonia leak is determined to have occurred.
[0055] The current ammonia storage threshold is determined based on the current operating conditions and the pre-calibrated ammonia storage thresholds corresponding to each operating condition.
[0056] Specifically, through ammonia storage experiments, the ammonia storage threshold of the catalyst under different temperatures and space velocities is obtained. Under combined operating conditions of different temperatures and space velocities, a constant flow rate of nitrogen oxides is introduced into the catalyst, and the urea injection rate is increased stepwise from a set initial value until the nitrogen oxide conversion efficiency begins to decrease, and / or the downstream ammonia sensor detects that the increase in NH3 concentration within a preset time interval is greater than or equal to a preset increment threshold (i.e., a sharp increase in NH3 concentration in a short period of time). The ammonia storage amount at this point is then taken as the ammonia storage threshold for that combined operating condition. Similarly, the ammonia storage amount can be calculated by the difference between the ammonia generated by the urea injection rate and the ammonia consumption required for nitrogen oxide consumption. The same method is used to determine the ammonia storage threshold for different combined operating conditions.
[0057] When detecting ammonia leaks, the corresponding ammonia storage threshold is determined based on the current temperature and current air velocity. Further, if none of the pre-calibrated operating conditions corresponding to each ammonia storage threshold have the same conditions as the current temperature and current air velocity, then the ammonia storage threshold corresponding to the operating condition with the smallest difference between the current temperature and current air velocity can be used as the current ammonia storage threshold. Alternatively, at least two operating conditions adjacent to the current temperature and current air velocity can be identified from each operating condition, and the average of the ammonia storage thresholds corresponding to these adjacent operating conditions can be used as the current ammonia storage threshold. For example, if the current temperature is 303°C and the current air velocity is 3333 h⁻¹... -1A query of the pre-set operating conditions revealed a temperature of 300℃ and an air velocity of 3300 h⁻¹. -1 The temperature is 300℃ and the space velocity is 3400h. -1 The temperature is 310℃ and the space velocity is 3300 h⁻¹. -1 And, the temperature is 310℃, and the air velocity is 3400h. -1 The four combined operating conditions are adjacent to the current operating condition. Therefore, the average of the ammonia storage thresholds corresponding to each adjacent operating condition is used as the current ammonia storage threshold. Alternatively, interpolation can be performed on each combined operating condition and its corresponding ammonia storage threshold to obtain curves between different operating conditions and ammonia storage thresholds. Based on the current temperature and current air velocity, the corresponding ammonia storage threshold in the curve is determined as the current ammonia storage threshold.
[0058] Understandably, if the current ammonia storage level is greater than or equal to the current ammonia storage threshold, it indicates that the catalyst carrier adsorption capacity is already oversaturated, which is a necessary condition for ammonia leakage to occur.
[0059] Furthermore, an ammonia storage threshold coefficient can be set. This threshold coefficient can be a value less than 1, such as a decimal between 0.9 and 1. If the current ammonia storage level is greater than or equal to the product of the current ammonia storage threshold and the ammonia storage threshold coefficient, and the deviation of the nitrogen oxide conversion efficiency ratio is greater than or equal to a preset deviation threshold, then an ammonia leak is determined to have occurred. In this embodiment, setting the ammonia storage threshold coefficient when comparing the current ammonia storage level has the advantage of improving the sensitivity of ammonia leak detection.
[0060] The deviation threshold is obtained through statistical analysis of the deviations in nitrogen oxide conversion efficiency (NOx) ratios corresponding to historical ammonia leaks and those under normal operating conditions. For example, if the NOx conversion efficiency ratio deviation under normal operating conditions is concentrated at or below 1.1, while the deviations corresponding to historical ammonia leaks are distributed between 1.2 and 1.3, the deviation threshold can be set to 1.2. Similarly, to improve the sensitivity of ammonia leak detection, a deviation threshold coefficient can be set, for example, 0.9. If the current ammonia storage level is greater than or equal to the product of the current ammonia storage level threshold and the ammonia storage level threshold coefficient, and the NOx conversion efficiency ratio deviation is greater than or equal to the product of the preset deviation threshold and the deviation threshold coefficient, then an ammonia leak is determined to have occurred.
[0061] In this embodiment, by jointly judging the current ammonia storage level and the deviation of the nitrogen oxide conversion efficiency ratio, high-precision and high-reliability indirect detection of ammonia leakage can be achieved without deploying an ammonia sensor.
[0062] Furthermore, upon confirmation of an ammonia leak, an ammonia leak alarm can be triggered, and / or a urea injection rate suppression strategy can be implemented. Specifically, the ammonia leak alarm can be triggered through voice announcements, flashing indicator lights, and sending ammonia leak alarm information to the backend server, or a combination of these methods. The urea injection rate suppression strategy can be implemented by reducing the current urea injection rate or shutting down the urea injection system.
[0063] Furthermore, when an ammonia leak is confirmed, the severity level of the current ammonia leak can be determined based on the deviation between the current ammonia storage level and the nitrogen oxide conversion efficiency ratio. Based on different severity levels, corresponding ammonia leak alarm forms and / or urea injection volume suppression strategies can be determined.
[0064] The technical solution of this invention determines whether ammonia leak detection conditions are met by using at least one operating parameter of the urea injection system, a nitrogen oxide sensor, and the catalyst. When the ammonia leak detection conditions are met, the current ammonia storage level of the catalyst is determined based on the current urea injection rate and the upstream nitrogen oxide content. Furthermore, the nitrogen oxide conversion efficiency ratio deviation within a preset time period is determined based on the upstream and downstream nitrogen oxide content. Finally, based on the current ammonia storage level and the nitrogen oxide conversion efficiency ratio deviation, it is determined whether an ammonia leak has occurred. This technical solution does not rely on an additional ammonia sensor. By setting ammonia leak detection conditions, it ensures that ammonia leak detection is performed only under steady-state operating conditions with high diagnostic reliability, reducing the false alarm rate. Simultaneously, the combined diagnostic mechanism based on the current ammonia storage level and the nitrogen oxide conversion efficiency ratio deviation improves the accuracy and reliability of ammonia leak detection.
[0065] Example 2
[0066] Figure 2 This is a flowchart of an ammonia leak detection method provided in Embodiment 2 of the present invention. Based on the above embodiments, the present invention further specifies the process for determining the conditions for ammonia leak detection.
[0067] like Figure 2 As shown, the method includes:
[0068] S210. Based on the upstream nitrogen oxide content of the upstream nitrogen oxide sensor, determine the upstream nitrogen oxide mass flow rate and the rate of change of the upstream nitrogen oxide mass flow rate; based on the downstream nitrogen oxide content of the downstream nitrogen oxide sensor, determine the downstream nitrogen oxide mass flow rate and the rate of change of the downstream nitrogen oxide mass flow rate; and based on the upstream nitrogen oxide content and the downstream nitrogen oxide content, determine the nitrogen oxide conversion efficiency of the actuator.
[0069] The upstream nitrogen oxide mass flow rate refers to the total mass of nitrogen oxides flowing through the upstream of the catalyst per unit time. This flow rate can be calculated by multiplying the upstream nitrogen oxide content by the engine exhaust flow rate and a unit conversion factor. The engine exhaust flow rate can be obtained from the engine control unit (ECU).
[0070] The rate of change of upstream nitrogen oxide mass flow rate can be expressed by the following formula: ,in, This indicates the upstream nitrogen oxide mass flow rate.
[0071] Similarly, the downstream nitrogen oxide mass flow rate refers to the total mass of nitrogen oxides flowing through the downstream of the catalyst per unit time. The downstream nitrogen oxide mass flow rate can be calculated by multiplying the downstream nitrogen oxide content by the engine exhaust flow rate and the unit conversion factor.
[0072] The rate of change in downstream nitrogen oxide mass flow rate can be expressed by the following formula: ,in, This indicates the upstream nitrogen oxide mass flow rate.
[0073] The nitrogen oxide conversion efficiency is expressed by the following formula: ,in, Indicates nitrogen oxide conversion efficiency. Indicates the downstream nitrogen oxide content, This indicates the upstream nitrogen oxide content.
[0074] S220. If the following conditions are met: urea over-spraying condition, catalyst nitrogen oxide conversion efficiency gradient condition, upstream nitrogen oxide mass flow rate non-low condition, upstream nitrogen oxide mass flow rate change rate stable condition, downstream nitrogen oxide mass flow rate non-low condition, and downstream nitrogen oxide mass flow rate change rate stable condition, then the ammonia leakage detection condition is met.
[0075] In this embodiment, a series of ammonia leak detection enabling conditions are set. Only when all the enabling conditions are met simultaneously is subsequent ammonia leak detection performed based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio. The advantages of this approach are twofold: firstly, it eliminates interference from special operating conditions such as engine transients and low-concentration signals, improving the accuracy of ammonia leak detection; secondly, by performing a joint judgment based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio only when the ammonia leak detection conditions are met, continuous ammonia leak detection is unnecessary, saving computational resources.
[0076] Urea over-spraying refers to a situation where, during the operation of a urea injection system, the amount of urea sprayed exceeds the theoretical amount required for the actual removal of nitrogen oxides.
[0077] Specifically, the conditions for meeting the urea over-spraying state include: if it is determined that the urea injection system, the upstream nitrogen and oxygen sensor, and the downstream nitrogen and oxygen sensor are all in working condition, and the urea injection feed ratio is greater than or equal to the preset feed ratio limit, then the current state is determined to be urea over-spraying.
[0078] Understandably, determining the urea over-spray status requires first ensuring that the urea injection system, upstream nitrogen and oxygen sensors, and downstream nitrogen and oxygen sensors are all in a fault-free working state before judging the urea injection feed ratio.
[0079] The urea injection feed ratio refers to the number of urea units required to remove one unit of nitrogen oxides. According to stoichiometry, 1 mol of NH3 is needed to reduce 1 kg of nitrogen oxides. The ratio of the urea injection amount corresponding to 1 mol of NH3 to 1 kg of nitrogen oxides is the urea injection feed ratio. In practical applications, ECUs typically set the urea injection feed ratio within the range of 1.05-1.15 when calculating the urea injection amount. For example, the feed ratio limit can be set to 1.2. When the urea injection feed ratio is greater than or equal to the preset feed ratio limit, ammonia slip will increase.
[0080] In this embodiment, by judging the state of urea over-spraying, the interference of insufficient urea injection on ammonia leak detection can be directly eliminated, thus avoiding false detection of ammonia leaks.
[0081] Specifically, satisfying the nitrogen oxide conversion efficiency gradient condition of the catalyst includes: if it is determined that the rate of change of nitrogen oxide conversion efficiency is less than or equal to a preset rate of change threshold, then the nitrogen oxide conversion efficiency gradient condition of the catalyst is satisfied.
[0082] Among them, the rate of change in nitrogen oxide conversion efficiency can be obtained through Calculations are performed. Under urea over-injection conditions, if the rate of change in nitrogen oxide conversion efficiency is less than or equal to a preset rate of change threshold, it indicates that the nitrogen oxide conversion efficiency has reached its limit and the catalyst is in a reaction state that worsens emissions.
[0083] Specifically, satisfying the condition that the upstream nitrogen oxide mass flow rate is not low includes: the upstream nitrogen oxide mass flow rate is greater than or equal to a preset first flow rate threshold. In this embodiment, the upstream nitrogen oxide mass flow rate is not low, which can eliminate the interference of low nitrogen oxide operating conditions on ammonia leak detection.
[0084] Specifically, satisfying the condition of stable upstream nitrogen oxide mass flow rate change includes: the upstream nitrogen oxide mass flow rate change is less than or equal to a preset first change rate threshold. In this embodiment, the upstream nitrogen oxide mass flow rate change being less than or equal to the preset first change rate threshold indicates that the upstream of the system is in a relatively stable reaction state.
[0085] Specifically, satisfying the condition that the downstream nitrogen oxide mass flow rate is not low includes: the downstream nitrogen oxide mass flow rate is greater than or equal to a preset second flow rate threshold. The first and second flow rate thresholds can be set and adjusted according to actual operating conditions, and the first and second flow rate thresholds are different. In this embodiment, the downstream nitrogen oxide mass flow rate being not low ensures the accuracy of the system's detection of the downstream nitrogen oxide change rate within a reasonable range.
[0086] Specifically, satisfying the condition of stable downstream nitrogen oxide mass flow rate change includes: the downstream nitrogen oxide mass flow rate change is less than or equal to a preset second change rate threshold. Similarly, the first and second change rate thresholds can be set and adjusted according to actual operating conditions, and the first and second change rate thresholds are different. In this embodiment, the downstream nitrogen oxide mass flow rate change being less than or equal to the preset second change rate threshold ensures a reaction state where downstream nitrogen oxide emissions increase due to ammonia leakage.
[0087] This embodiment illustrates ammonia leak detection when all of the above conditions are met simultaneously. It can be understood that, depending on the specific needs of actual applications, the ammonia leak detection can be performed when at least one or more of the above conditions are met, thereby improving the sensitivity of ammonia leak detection.
[0088] S230. When the ammonia leak detection conditions are met, determine the current ammonia storage of the catalyst based on the current urea injection volume and the upstream nitrogen oxide content, and determine the nitrogen oxide conversion efficiency ratio deviation within a preset time period based on the upstream nitrogen oxide content and the downstream nitrogen oxide content.
[0089] S240. Based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio, determine whether an ammonia leak has occurred.
[0090] The specific implementation methods for determining the current ammonia storage level, determining the deviation of the nitrogen oxide conversion efficiency ratio, and determining whether an ammonia leak has occurred based on the current ammonia storage level and the deviation of the nitrogen oxide conversion efficiency ratio have been described in the above embodiments, and will not be repeated here.
[0091] The technical solution of this invention, by setting multiple stringent enabling conditions, including satisfying urea over-injection conditions, catalyst nitrogen oxide conversion efficiency gradient conditions, upstream nitrogen oxide mass flow rate not low conditions, upstream nitrogen oxide mass flow rate change rate stability conditions, downstream nitrogen oxide mass flow rate not low conditions, and downstream nitrogen oxide mass flow rate change rate stability conditions, effectively filters out interference from transient engine operating conditions and low nitrogen oxide levels. This ensures that ammonia leak detection is only performed under highly reliable and stable operating conditions, reducing the false alarm rate of ammonia leaks. Simultaneously, when the ammonia leak detection conditions are met, the current ammonia storage level of the catalyst is determined based on the current urea injection quantity and upstream nitrogen oxide content. Furthermore, the nitrogen oxide conversion efficiency ratio deviation within a preset time period is determined based on the upstream and downstream nitrogen oxide content. This innovatively proposes a joint diagnostic mechanism based on dual judgment criteria of current ammonia storage level and nitrogen oxide conversion efficiency ratio deviation. The excessive current urea injection quantity reflects the saturation state of the catalyst carrier's adsorption capacity, a necessary condition for ammonia leaks. The excessive deviation in the nitrogen oxide conversion efficiency ratio revealed, from a statistical perspective, an abnormal characteristic of catalyst activity decreasing from a high level due to ammonia leakage, which is a sufficient condition for ammonia leakage to occur. The combined verification of these two factors ensures the accuracy of the ammonia leakage detection results. The technical solution of this invention, without relying on an additional ammonia sensor, achieves high-precision and high-reliability indirect detection of ammonia leakage.
[0092] Example 3
[0093] Figure 3 This is a schematic diagram of an ammonia leak detection device provided in Embodiment 3 of the present invention. Figure 3 As shown, the device includes:
[0094] The ammonia leak detection condition judgment module 310 is used to determine whether the ammonia leak detection conditions are met based on at least one of the operating parameters of the urea injection system, the nitrogen and oxygen sensor, and the catalyst.
[0095] The current ammonia storage and nitrogen oxide conversion efficiency ratio deviation calculation module 320 is used to determine the current ammonia storage of the catalyst based on the current urea injection volume and the upstream nitrogen oxide content when the ammonia leakage detection conditions are met, and to determine the nitrogen oxide conversion efficiency ratio deviation within a preset time period based on the upstream nitrogen oxide content and the downstream nitrogen oxide content.
[0096] The ammonia leakage detection module 330 is used to determine whether an ammonia leak has occurred based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio.
[0097] The technical solution of this invention determines whether ammonia leak detection conditions are met by using at least one operating parameter of the urea injection system, a nitrogen oxide sensor, and the catalyst. When the ammonia leak detection conditions are met, the current ammonia storage level of the catalyst is determined based on the current urea injection rate and the upstream nitrogen oxide content. Furthermore, the nitrogen oxide conversion efficiency ratio deviation within a preset time period is determined based on the upstream and downstream nitrogen oxide content. Finally, based on the current ammonia storage level and the nitrogen oxide conversion efficiency ratio deviation, it is determined whether an ammonia leak has occurred. This technical solution does not rely on an additional ammonia sensor. By setting ammonia leak detection conditions, it ensures that ammonia leak detection is performed only under steady-state operating conditions with high diagnostic reliability, reducing the false alarm rate. Simultaneously, the combined diagnostic mechanism based on the current ammonia storage level and the nitrogen oxide conversion efficiency ratio deviation improves the accuracy and reliability of ammonia leak detection.
[0098] Based on the above embodiments, optionally, the ammonia leak detection condition judgment module 310 includes:
[0099] The parameter calculation unit is used to determine the upstream nitrogen oxide mass flow rate and the rate of change of the upstream nitrogen oxide mass flow rate based on the upstream nitrogen oxide content of the upstream nitrogen oxide sensor, to determine the downstream nitrogen oxide mass flow rate and the rate of change of the downstream nitrogen oxide mass flow rate based on the downstream nitrogen oxide content of the downstream nitrogen oxide sensor, and to determine the nitrogen oxide conversion efficiency of the actuator based on the upstream nitrogen oxide content and the downstream nitrogen oxide content.
[0100] The ammonia leak detection condition judgment unit is used to determine whether the ammonia leak detection conditions are met if the following conditions are met: urea over-spraying state condition, catalyst nitrogen oxide conversion efficiency gradient condition, upstream nitrogen oxide mass flow rate non-low condition, upstream nitrogen oxide mass flow rate change rate stable condition, downstream nitrogen oxide mass flow rate non-low condition, and downstream nitrogen oxide mass flow rate change rate stable condition.
[0101] Based on the above embodiments, optionally, the ammonia leak detection condition judgment unit is specifically used for:
[0102] If it is determined that the urea injection system, the upstream nitrogen and oxygen sensor, and the downstream nitrogen and oxygen sensor are all in working condition, and the urea injection feed ratio is greater than or equal to the preset feed ratio limit, then the current state is determined to be urea over-injection.
[0103] Based on the above embodiments, optionally, the ammonia leak detection condition judgment unit is specifically used for:
[0104] If the rate of change of nitrogen oxide conversion efficiency is determined to be less than or equal to a preset rate of change threshold, then the nitrogen oxide conversion efficiency gradient condition of the catalyst is satisfied.
[0105] Based on the above embodiments, optionally, the current ammonia storage capacity and nitrogen oxide conversion efficiency ratio deviation calculation module 320 includes:
[0106] The ammonia generation determination unit is used to determine the ammonia generation based on the current urea injection rate.
[0107] The ammonia consumption determination unit is used to determine the amount of ammonia required for the catalyst to consume the upstream nitrogen oxide content based on the upstream nitrogen oxide content.
[0108] The current ammonia storage level determination unit is used to determine the current ammonia storage level of the catalyst based on the ammonia generation and ammonia consumption.
[0109] Based on the above embodiments, optionally, the current ammonia storage capacity and nitrogen oxide conversion efficiency ratio deviation calculation module 320 includes:
[0110] The nitrogen oxide conversion efficiency determination unit is used to determine the nitrogen oxide conversion efficiency within a preset time period based on the upstream nitrogen oxide content and the downstream nitrogen oxide content within a preset time period.
[0111] The nitrogen oxide conversion efficiency ratio deviation determination unit is used to determine the nitrogen oxide conversion efficiency ratio deviation based on the maximum and average values of nitrogen oxide conversion efficiency within a preset time period.
[0112] Based on the above embodiments, optionally, the ammonia leakage detection module 330 includes:
[0113] The ammonia leakage detection unit is used to determine that an ammonia leakage has occurred if the current ammonia storage level is greater than or equal to the current ammonia storage level threshold and the nitrogen oxide conversion efficiency ratio deviation is greater than or equal to a preset deviation threshold.
[0114] The current ammonia storage threshold is determined based on the current operating conditions and the pre-calibrated ammonia storage thresholds corresponding to each operating condition.
[0115] The ammonia leak detection device provided in this embodiment of the invention can execute the ammonia leak detection method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.
[0116] Example 4
[0117] Figure 4A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.
[0118] like Figure 4 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.
[0119] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.
[0120] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as ammonia leak detection methods.
[0121] In some embodiments, the ammonia leak detection method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the ammonia leak detection method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the ammonia leak detection method by any other suitable means (e.g., by means of firmware).
[0122] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.
[0123] Computer programs used to implement the methods of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable ammonia leak detection device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.
[0124] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.
[0125] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).
[0126] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.
[0127] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through a communication network. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.
[0128] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and no limitation is imposed herein.
[0129] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A method for detecting ammonia leaks, characterized in that, include: Determine whether the ammonia leak detection conditions are met based on at least one of the operating parameters of the urea injection system, nitrogen and oxygen sensor, and catalyst. When the ammonia leak detection conditions are met, the current ammonia storage of the catalyst is determined based on the current urea injection volume and the upstream nitrogen oxide content, and the nitrogen oxide conversion efficiency ratio deviation within a preset time period is determined based on the upstream nitrogen oxide content and the downstream nitrogen oxide content. Based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio, determine whether an ammonia leak has occurred.
2. The method according to claim 1, characterized in that, Determine whether the ammonia leak detection conditions are met based on at least one operating parameter of the urea injection system, nitrogen and oxygen sensor, and catalyst, including: Based on the upstream nitrogen oxide content of the upstream nitrogen oxide sensor, determine the upstream nitrogen oxide mass flow rate and the rate of change of the upstream nitrogen oxide mass flow rate; based on the downstream nitrogen oxide content of the downstream nitrogen oxide sensor, determine the downstream nitrogen oxide mass flow rate and the rate of change of the downstream nitrogen oxide mass flow rate; and based on the upstream and downstream nitrogen oxide contents, determine the nitrogen oxide conversion efficiency of the actuator. If the following conditions are met: urea over-spraying state, catalyst nitrogen oxide conversion efficiency gradient, upstream nitrogen oxide mass flow rate is not low, upstream nitrogen oxide mass flow rate change rate is stable, downstream nitrogen oxide mass flow rate is not low, and downstream nitrogen oxide mass flow rate change rate is stable, then the ammonia leakage detection conditions are met.
3. The method according to claim 2, characterized in that, The conditions for satisfying the urea overspray state include: If it is determined that the urea injection system, the upstream nitrogen and oxygen sensor, and the downstream nitrogen and oxygen sensor are all in working condition, and the urea injection feed ratio is greater than or equal to the preset feed ratio limit, then the current state is determined to be urea over-injection.
4. The method according to claim 2, characterized in that, The conditions for satisfying the nitrogen oxide conversion efficiency gradient of the catalyst include: If the rate of change of nitrogen oxide conversion efficiency is determined to be less than or equal to a preset rate of change threshold, then the nitrogen oxide conversion efficiency gradient condition of the catalyst is satisfied.
5. The method according to claim 1, characterized in that, Based on the current urea injection rate and upstream nitrogen oxide content, determine the current ammonia storage level of the catalyst, including: Determine the ammonia generation amount based on the current urea injection rate; The amount of ammonia required for the catalyst to consume the upstream nitrogen oxide content is determined based on the upstream nitrogen oxide content. The current ammonia storage level of the catalyst is determined based on the ammonia production and consumption.
6. The method according to claim 1, characterized in that, Based on the upstream and downstream nitrogen oxide content, determine the deviation of the nitrogen oxide conversion efficiency ratio within a preset time period, including: The nitrogen oxide conversion efficiency within the preset time period is determined based on the upstream and downstream nitrogen oxide contents within the preset time period. The deviation of the nitrogen oxide conversion efficiency ratio is determined based on the maximum and average values of the nitrogen oxide conversion efficiency within a preset time period.
7. The method according to claim 1, characterized in that, Based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio, determine whether an ammonia leak has occurred, including: If the current ammonia storage level is determined to be greater than or equal to the current ammonia storage level threshold, and the nitrogen oxide conversion efficiency ratio deviation is greater than or equal to the preset deviation threshold, then an ammonia leak is determined to have occurred. The current ammonia storage threshold is determined based on the current operating conditions and the pre-calibrated ammonia storage thresholds corresponding to each operating condition.
8. An ammonia leak detection device, characterized in that, include: The ammonia leak detection condition judgment module is used to determine whether the ammonia leak detection conditions are met based on at least one of the operating parameters of the urea injection system, the nitrogen and oxygen sensor, and the catalyst. The module for calculating the current ammonia storage and nitrogen oxide conversion efficiency ratio deviation is used to determine the current ammonia storage of the catalyst based on the current urea injection volume and the upstream nitrogen oxide content when the ammonia leakage detection conditions are met, and to determine the nitrogen oxide conversion efficiency ratio deviation within a preset time period based on the upstream nitrogen oxide content and the downstream nitrogen oxide content. The ammonia leak detection module is used to determine whether an ammonia leak has occurred based on the current ammonia storage level and the deviation in the nitrogen oxide conversion efficiency ratio.
9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the ammonia leak detection method as described in any one of claims 1-7.
10. A storage medium for storing computer-executable instructions, characterized in that, The computer-executable instructions, when executed by a computer processor, are used to perform the ammonia leak detection method as described in any one of claims 1-7.