Natural gas engine aftertreatment catalyst aging rate control method and related device

Abstract

The invention provides a natural gas engine aftertreatment catalyst aging rate control method and a related device, and relates to the field of engines. According to the scheme, when an engine is in a strong transient working condition, the actual oxygen storage amount descending rate of an aftertreatment catalyst is obtained; and comparing the actual oxygen storage amount reduction rate with a theoretical oxygen storage amount reduction rate calculated based on an aging model, calculating a probability value of the engine in a high-methane working condition based on a difference value between the actual oxygen storage amount reduction rate and the theoretical oxygen storage amount reduction rate, and when the probability value is greater than a target threshold value, adjusting target parameters of the engine so as to reduce the actual oxygen storage amount reduction rate. Therefore, the aging rate of the after-treatment catalyst under the high-methane working condition is reduced, and the service life of the after-treatment catalyst is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a method for controlling the aging rate of a natural gas engine after-treatment catalyst and a related device. Background Art

[0002] Current natural gas engine control strategies rely solely on torque limiting and lean-burn control when a misfire is detected to prevent excessively high exhaust gas temperatures from accelerating the aging rate of the after-treatment three-way catalytic converter (TWC). However, under high-methane operating conditions, the engine's after-treatment catalyst can experience abnormally rapid aging. This condition cannot be identified through engine misfire detection, and therefore, no corresponding protection can be provided, resulting in rapid aging of the after-treatment catalyst. Summary of the Invention

[0003] In view of this, an embodiment of the present invention provides a method and related device for controlling the aging rate of a natural gas engine after-treatment catalyst to reduce the aging rate of the after-treatment catalyst under high methane conditions and increase the service life of the after-treatment catalyst.

[0004] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0005] A method for controlling an aging rate of a natural gas engine aftertreatment catalyst comprises:

[0006] Target data under the current engine operating condition is acquired using an aging model to obtain a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition. The aging model is a model constructed based on the Arrhenius equation for calculating the theoretical oxygen storage capacity decrease rate of the engine.

[0007] Determining whether the current operating condition of the engine is a strong transient operating condition, wherein the strong transient operating condition refers to a transient operating condition in which the fluctuation amplitude of the engine system parameter per unit time is greater than a calibrated value;

[0008] When the current operating condition of the engine is a strong transient condition:

[0009] Obtaining an actual oxygen storage capacity decrease rate of the post-treatment catalyst corresponding to the current operating condition;

[0010] When the actual oxygen storage amount decrease rate is greater than the theoretical oxygen storage amount decrease rate, a probability value of the engine experiencing a high methane operating condition is calculated based on the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, wherein the greater the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, the higher the probability value;

[0011] When the probability value exceeds a target threshold, the target parameter of the engine is adjusted to reduce the actual oxygen storage amount decrease rate.

[0012] Optionally, in the above-mentioned natural gas engine after-treatment catalyst aging rate control method, after adjusting the target parameters of the engine, the method further includes:

[0013] After waiting for the set time, the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate at the current moment are obtained again;

[0014] Determine whether the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate is within an allowable error range. When it is not within the allowable error range, continue to adjust the target parameter until the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate is within the allowable error range.

[0015] Optionally, in the above-mentioned natural gas engine after-treatment catalyst aging rate control method, the determining whether the current operating condition of the engine is a strong transient operating condition includes:

[0016] Obtaining at least one engine operating parameter of the engine under the current operating condition, including the speed, load rate, EGR rate, throttle opening, intake pressure, lambda, throttle and ignition angle;

[0017] Based on the acquired engine operating parameters, it is determined whether the current operating condition of the engine is a strong transient operating condition.

[0018] Optionally, in the above-mentioned natural gas engine after-treatment catalyst aging rate control method, the aging model is used to obtain target data under the current engine operating condition to obtain the theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition, including:

[0019] A reaction temperature of the after-treatment catalyst under the current operating condition and a duration of the current operating condition are obtained, and the reaction temperature and the duration are input into an aging model to calculate a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition through the aging model.

[0020] Optionally, in the above-mentioned natural gas engine after-treatment catalyst aging rate control method, the reaction temperature and the duration are input into the aging model, including:

[0021] Correcting the reaction temperature and duration based on the correction parameter;

[0022] The corrected reaction temperature and duration are input into the aging model.

[0023] Optionally, in the above-mentioned natural gas engine after-treatment catalyst aging rate control method, adjusting the target parameters of the engine includes:

[0024] Identifying an anomaly level corresponding to the probability value;

[0025] Target parameters of the engine are adjusted to match the abnormality level.

[0026] Optionally, in the above-mentioned natural gas engine after-treatment catalyst aging rate control method, after determining that the current operating condition of the engine is a strong transient operating condition and before obtaining the actual oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition, the method further includes:

[0027] Obtain the cumulative statistical time that the after-treatment catalyst is in a strong transient operating condition during its current life cycle. When the cumulative statistical time reaches a preset statistical time, execute the steps of: obtaining an actual oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition and subsequent steps.

[0028] Optionally, the above-mentioned natural gas engine after-treatment catalyst aging rate control method further includes:

[0029] A misfire rate of the engine is obtained, and when the misfire rate is greater than a preset value, a bypass line is controlled to bypass the post-treatment catalyst.

[0030] A natural gas engine after-treatment catalyst aging rate control device, comprising:

[0031] an operating condition identification unit, configured to determine whether the current operating condition of the engine is a strong transient operating condition, and trigger the actual oxygen storage capacity decrease rate acquisition unit, the probability value calculation unit, and the parameter adjustment unit when the engine is in the strong transient operating condition. The strong transient operating condition refers to a transient operating condition in which the fluctuation amplitude of the engine system parameter per unit time is greater than a calibrated value;

[0032] a theoretical oxygen storage capacity decrease rate calculation unit, configured to acquire target data under a current engine operating condition using an aging model to obtain a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition, wherein the aging model is a model constructed based on the Arrhenius equation for calculating the theoretical oxygen storage capacity decrease rate of the engine;

[0033] an actual oxygen storage amount decrease rate acquisition unit, configured to acquire an actual oxygen storage amount decrease rate of the post-treatment catalyst corresponding to the current operating condition;

[0034] a probability value calculation unit, configured to calculate, when the actual oxygen storage amount decrease rate is greater than the theoretical oxygen storage amount decrease rate, a probability value of the engine experiencing a high methane operating condition based on a difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, wherein the greater the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, the higher the probability value;

[0035] A parameter adjustment unit is used to adjust the target parameter of the engine when the probability value exceeds a target threshold value, so as to reduce the actual oxygen storage capacity decrease rate.

[0036] A natural gas engine comprises the above-mentioned natural gas engine after-treatment catalyst aging rate control device, wherein the natural gas engine after-treatment catalyst aging rate control device is integrated into an engine controller or a vehicle controller.

[0037] A car comprises the above-mentioned natural gas engine.

[0038] Based on the above technical solution, the above solution provided by the embodiment of the present invention obtains the actual oxygen storage decrease rate of the after-treatment catalyst when the engine is in a strong transient operating condition, compares the actual oxygen storage decrease rate with the theoretical oxygen storage decrease rate calculated based on the aging model, and calculates the probability value of the engine being in a high methane operating condition based on the difference between the two. When the probability value is greater than the target threshold, the target parameters of the engine are adjusted to reduce the actual oxygen storage decrease rate, thereby reducing the aging rate of the after-treatment catalyst under the high methane operating condition and increasing the life of the after-treatment catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0040] Figure 1 A flow chart of a method for controlling the aging rate of a natural gas engine after-treatment catalyst provided at the time of this application;

[0041] Figure 2 A schematic diagram of the output signal of the aging model provided in an embodiment of the present application;

[0042] Figure 3 A schematic structural diagram of an engine after-treatment system provided in an embodiment of the present application;

[0043] Figure 4This is a schematic structural diagram of a natural gas engine after-treatment catalyst aging rate control device provided in this application. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] First, let me explain the relevant professional terms used in this application:

[0046] Natural gas engine: A natural gas engine is an internal combustion engine that uses natural gas as fuel and is widely used in transportation, power generation and industrial fields. The current technical route adopted by China VI is: equivalent + EGR + TWC

[0047] Three-Way Catalytic Converter: It is the core component of the automobile exhaust purification system, mainly used to reduce the three main harmful gases emitted by the engine: carbon monoxide (CO) is oxidized into carbon dioxide (CO2), and hydrocarbons (HC) are oxidized into water (H2O) and carbon dioxide (CO2).

[0048] Nitrogen oxides (NO x The fuel is reduced to nitrogen (N2) and oxygen (O2). This oxidation-reduction reaction is triggered at high temperatures (above 250°C) using precious metal catalysts such as platinum (Pt), palladium (Pd), and rhodium (Rh). This reaction requires precise control of the air-fuel ratio (close to the theoretical value of 17:1) using an oxygen sensor.

[0049] Catalyst aging refers to the phenomenon in which a catalyst's catalytic performance (decreased oxygen storage capacity and fewer active sites) gradually declines over long-term use due to chemical, thermodynamic, and mechanical factors. This aging reduces the catalyst's conversion efficiency for harmful gases (such as CO, HC, and NOx), thereby affecting emissions performance.

[0050] Misfire: A misfire in a natural gas engine occurs when the spark plug fails to ignite the fuel-air mixture during the engine's operating cycle, resulting in no work being performed. This condition affects engine performance and emissions. Causes of misfires can include spark plug failure, ignition system problems, excessive or insufficient fuel-air mixture concentrations, and insufficient cylinder pressure. To ensure engine emissions meet standards, regulations set limits on misfire rates. Misfire rates are typically diagnosed using sensors that detect engine vibration, pressure changes, or changes in emissions composition. Modern engines are equipped with diagnostic systems that can monitor and record misfires in real time.

[0051] Arrhenius equation: The core formula in chemical kinetics, used to describe the relationship between the reaction rate constant k and temperature T, and can be used to describe the rates of various physical and chemical changes during the thermal aging of catalysts.

[0052] The thermal aging mechanism of catalysts follows the Arrhenius equation, and temperature is the key factor affecting the aging rate of catalysts.

[0053] Reaction rate of catalyst: ;

[0054] In the above formula, A is the pre-exponential factor, the value of which is related to the reaction temperature. In this embodiment, the reaction temperature refers to the exhaust gas temperature; Ea is the activation energy; T is the catalyst temperature, which can be equivalent to the exhaust gas temperature; and R is the ideal gas constant, which is 8.314 J / (mol·K).

[0055] To measure the cumulative degree of thermal effect of the catalyst during the aging cycle, it is necessary to calculate the integral of the aging reaction rate over time, that is: ;

[0056] The aging rate refers to the rate of decrease of the reaction rate. It refers to the pre-exponential factor corresponding to temperature T, H(T) is the integral of the aging reaction rate over time; t is the cumulative time of the thermal effect.

[0057] Equivalence relationship and model establishment: When the cumulative thermal effects of different thermal aging processes are the same (thermal aging has the same damaging effect on the TWC), the degradation rates of the TWC are essentially the same for both aging processes. Based on this, the average temperature of the TWC during the conventional aging cycle (the entire period from activation to failure) is divided into intervals. The average temperature and time in the i-th interval are taken as and For example, the temperature range of the TWC during its entire life cycle is 200~650℃, with each 50℃ interval as an interval. At the same time, the proportion (time) of each temperature interval is counted, and the time is , then the Arrhenius equation can be used to calculate the target temperature for rapid aging The equivalent time required to complete TWC in the ith interval to obtain the same thermal effect accumulation ,have . Equivalent time of all temperature ranges in conventional aging cycle The sum is the rapid aging target temperature The equivalent time under , .

[0058] Based on the aforementioned Arrhenius equation and theory, bench tests were conducted to construct aging models for engines of various specifications and types. The aging model can obtain target engine data and, based on the target data, calculate the theoretical oxygen storage rate of decrease and the theoretical oxygen storage capacity of the after-treatment catalyst corresponding to the real-time data. That is, the input of the aging model is the target engine data, and the output of the aging model is the theoretical oxygen storage rate of decrease and the theoretical oxygen storage capacity of the after-treatment catalyst.

[0059] Based on the above aging model, this application constructs a natural gas engine after-treatment catalyst aging rate control method, see Figure 1 , the method may include:

[0060] Step S101: using an aging model to obtain target data under the current operating condition of the engine, and obtaining a theoretical oxygen storage capacity decrease rate of the post-treatment catalyst corresponding to the current operating condition.

[0061] In this solution, the engine sends real-time target data under various operating conditions to the aging model. The aging model obtains the theoretical oxygen storage decrease rate of the after-treatment catalyst corresponding to the current operating condition based on internal calculations. Of course, the aging model can also calculate the theoretical oxygen storage capacity of the after-treatment catalyst corresponding to the current operating condition. However, in this embodiment, only the theoretical oxygen storage decrease rate is used.

[0062] During the entire life cycle of the after-treatment catalyst, the theoretical oxygen storage capacity decrease rate and the theoretical oxygen storage capacity output by the aging model are as follows: Figure 2 As shown, Figure 2 The L1 curve in the figure represents the theoretical oxygen storage capacity decrease rate of the after-treatment catalyst at each moment, and the L2 curve is used to characterize the oxygen storage capacity at each moment.

[0063] Step S102: Determine whether the current operating condition of the engine is a strong transient operating condition.

[0064] The strong transient operating condition refers to a transient operating condition in which the fluctuation amplitude of the engine system parameters per unit time is greater than the calibrated value.

[0065] In this embodiment, the engine system parameters may include any one or more of engine speed, load factor, EGR rate, throttle opening, intake pressure, lambda, throttle, and ignition angle. These parameters reflect the engine's operating state, and changes in different parameters during engine operation have different meanings. For example, engine speed reflects the rotational speed of the engine crankshaft, and torque reflects the magnitude of the engine's output torque. When the fluctuation amplitude of one or more system parameters reaches a certain value within a unit time, the engine is considered to have experienced a transient condition. When the fluctuation amplitude continues to increase and exceeds the corresponding calibration value, the current engine operating condition is determined to be a severe transient condition. For example, for engine speed, within each unit time interval, the difference between the current speed and the previous speed is calculated, and the absolute value is taken as the speed fluctuation amplitude within that unit time. When the speed fluctuation amplitude exceeds the calibration value, the engine is considered to be in a severe transient condition.

[0066] When the current operating condition of the engine is a strong transient operating condition, subsequent steps are executed; otherwise, the current operating condition of the engine continues to be detected.

[0067] Step S103: obtaining the actual oxygen storage capacity decrease rate of the post-treatment catalyst corresponding to the current operating condition.

[0068] When the engine is determined to be in a strong transient operating condition, it indicates that the engine may be in a high methane operating condition, requiring further analysis to determine whether the engine is in a high methane operating condition. Because prior art techniques cannot directly detect whether an engine is in a high methane operating condition, the applicant considers that the actual oxygen storage decrease rate of the aftertreatment catalyst under high methane operating conditions differs significantly from the theoretical oxygen storage decrease rate of the aftertreatment catalyst. Based on this principle, the present application analyzes whether the current engine operating condition is a high methane operating condition. Therefore, it is necessary to obtain the actual oxygen storage decrease rate of the aftertreatment catalyst corresponding to the current operating condition. Calculating the actual oxygen storage decrease rate can be performed by obtaining the actual oxygen storage of the aftertreatment catalyst at each moment, as calculated by the vehicle controller or the engine controller based on data such as aftertreatment temperature, exhaust gas flow rate, lambda, after-oxygen signal, and time. The actual oxygen storage decrease rate of the aftertreatment catalyst is calculated based on the difference between the actual oxygen storage at the previous moment and the actual oxygen storage at the current moment.

[0069] Step S104: When the actual oxygen storage capacity decrease rate is greater than the theoretical oxygen storage capacity decrease rate, a probability value of the engine experiencing a high methane operating condition is calculated based on the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate.

[0070] The greater the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate, the higher the probability value. The present application can pre-configure the probability values of high methane conditions corresponding to each difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate.

[0071] In this step, after the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate are calculated, the two are compared. When the actual oxygen storage amount decrease rate is not greater than the theoretical oxygen storage amount decrease rate, it indicates that the after-treatment catalyst is in good working condition and there is no need to intervene in the engine operation. When it is detected that the actual oxygen storage amount decrease rate is greater than the theoretical oxygen storage amount decrease rate, it indicates that the aging rate of the after-treatment catalyst is faster than the aging rate under the theoretical state. At this time, the engine may be in a high methane working condition. At this time, the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate is calculated, and based on the mapping relationship between the difference and the probability value, the probability value of the engine in a high methane working condition corresponding to the current difference is determined.

[0072] Step S105: When the probability value exceeds a target threshold, adjusting the target parameters of the engine.

[0073] In this step, after determining the probability value of the engine entering a high methane operating condition, if the probability value is low, in order to ensure the reliability of engine operation, there is no need to intervene in engine operation. When it is detected that the probability value exceeds the target threshold, it indicates that the engine is likely to be in a high methane operating condition. At this time, in order to reduce the aging rate of the after-treatment catalyst, it is necessary to intervene in engine operation and adjust the target parameters of the engine to reduce the actual oxygen storage capacity decrease rate.

[0074] In this embodiment, when the engine is in a strong transient operating condition, the actual oxygen storage capacity decrease rate of the after-treatment catalyst is obtained, and the actual oxygen storage capacity decrease rate is compared with the theoretical oxygen storage capacity decrease rate calculated based on an aging model. Based on the difference between the two, a probability value of the engine being in a high methane operating condition is calculated. When the probability value is greater than a target threshold, the target parameters of the engine are adjusted to reduce the actual oxygen storage capacity decrease rate, thereby reducing the aging rate of the after-treatment catalyst under high methane operating conditions and increasing the life of the after-treatment catalyst.

[0075] In this embodiment, after the target parameters of the engine are adjusted, in order to ensure the adjustment effect, the above scheme also includes: after waiting for a set period of time, obtaining the actual oxygen storage decrease rate of the after-treatment catalyst and the theoretical oxygen storage decrease rate of the after-treatment catalyst at the current moment based on the above-mentioned step process again, and judging whether the difference between the actual oxygen storage decrease rate and the theoretical oxygen storage decrease rate at the current moment is within a preset allowable error range. When it is not within the allowable error range, it indicates that the target parameters have not been adjusted in place, and the target parameters still need to be adjusted until it is detected that the difference between the actual oxygen storage decrease rate and the theoretical oxygen storage decrease rate is within the allowable error range.

[0076] In this embodiment, the target data includes the reaction temperature of the after-treatment catalyst and the duration of the current operating condition (high transient operating condition). After determining the reaction temperature and duration, the reaction temperature and duration are used as input data for the aging model. The aging model can then process the reaction temperature and duration based on the model's built-in algorithm to calculate the theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition.

[0077] In this embodiment, different engines have different heat transfer properties, which may result in a certain deviation between the collected reaction temperature and duration and the actual reaction temperature and duration. Therefore, this application pre-configures corresponding correction parameters based on the engine type. After obtaining the reaction temperature and duration, the correction parameters are used to correct the reaction temperature and duration, and the corrected reaction temperature and duration are input into the aging model, so that the aging model calculates the theoretical oxygen storage capacity decrease rate based on the corrected reaction temperature and duration.

[0078] In this embodiment, target parameters corresponding to different probability values can be preconfigured. For example, if the probability value is relatively low, only the air and combustion models of the engine under transient operating conditions need to be adjusted. If the probability value is relatively high, the adjustments to the air and combustion models can be supplemented by further adjusting the EGR system transiently while increasing the engine's intake flow rate, thereby improving combustion efficiency and reducing the rate of decrease in the actual oxygen storage capacity of the aftertreatment catalyst. Specifically, in the above-described embodiment, adjusting the target parameters of the engine specifically includes identifying the abnormality level corresponding to the probability value and adjusting the target parameters of the engine corresponding to the abnormality level. The target parameters corresponding to different abnormality levels have different content and / or adjustment amplitudes.

[0079] In this embodiment, considering that the performance change of the after-treatment catalyst is a gradual process, especially under strong transient conditions, its performance changes such as the decrease in oxygen storage capacity do not occur instantaneously, but gradually appear as the conditions continue to act. In the initial stage of the life cycle of the after-treatment catalyst, the catalyst has a certain degree of adaptability and self-regulation ability, and can better maintain its oxygen storage performance. Only after a certain period of strong transient conditions will its internal chemical composition, physical structure, etc. gradually change, resulting in significant changes in performance indicators such as the rate of decrease in oxygen storage capacity. For example, the precious metal active components in the catalyst may gradually undergo agglomeration, sintering, etc. under strong transient conditions. These changes require a certain amount of time to accumulate before they have a significant impact on the oxygen storage performance. Therefore, in an embodiment, in order to reduce the amount of data calculation of the computing system, after determining that the current operating condition is a strong transient operating condition, it is necessary to first obtain the cumulative statistical time that the after-treatment catalyst is in the strong transient operating condition during the current life cycle, and determine whether the cumulative statistical time has reached a preset statistical time. When the cumulative statistical time has reached the preset statistical time, continue to execute the step of obtaining the actual oxygen storage capacity reduction rate of the after-treatment catalyst corresponding to the current operating condition and the subsequent steps. In this embodiment, see Figure 3 The after-treatment catalyst has a bypass line. The method further includes obtaining a misfire rate of the engine. When the misfire rate is greater than a preset value, it indicates that the oxygen storage capacity of the after-treatment catalyst decreases too quickly. At this time, the bypass line is controlled to bypass the after-treatment catalyst so that the exhaust gas only passes through a local catalyst at most, thereby avoiding overall damage to the after-treatment catalyst under such operating conditions.

[0080] This embodiment discloses a device for controlling the aging rate of a natural gas engine after-treatment catalyst. For the specific working contents of each unit in the device, please refer to the contents of the above method embodiment.

[0081] The following describes an aging rate control device for a natural gas engine after-treatment catalyst provided by an embodiment of the present invention. The aging rate control device for a natural gas engine after-treatment catalyst described below and the aging rate control method for a natural gas engine after-treatment catalyst described above can be referenced to each other.

[0082] See also Figure 4 The aging rate control device for the natural gas engine after-treatment catalyst disclosed in this embodiment includes:

[0083] The operating condition identification unit 10 corresponds to step S102 in the above method and is used to determine whether the current operating condition of the engine is a strong transient operating condition. When the engine is in the strong transient operating condition, the actual oxygen storage capacity decrease rate acquisition unit, the probability value calculation unit, and the parameter adjustment unit are triggered. The strong transient operating condition refers to a transient operating condition in which the fluctuation amplitude of the engine system parameter per unit time is greater than the calibration value;

[0084] a theoretical oxygen storage capacity decrease rate calculation unit 20, corresponding to step S101 in the above method, for acquiring target data under the current operating condition of the engine using an aging model to obtain a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition. The aging model is a model constructed based on the Arrhenius equation for calculating the theoretical oxygen storage capacity decrease rate of the engine;

[0085] The actual oxygen storage amount decreasing rate obtaining unit 30 corresponds to step S103 in the above method and is used to obtain the actual oxygen storage amount decreasing rate of the post-treatment catalyst corresponding to the current operating condition;

[0086] a probability value calculation unit 40, corresponding to step S104 in the above method, for calculating, when the actual oxygen storage amount decrease rate is greater than the theoretical oxygen storage amount decrease rate, a probability value of the engine experiencing a high methane operating condition based on a difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, wherein the greater the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, the higher the probability value;

[0087] The parameter adjustment unit 50 corresponds to step S105 in the above method and is configured to adjust the target parameters of the engine to reduce the actual oxygen storage capacity decrease rate when the probability value exceeds the target threshold.

[0088] Corresponding to the above method, the parameter adjustment unit 50 in the above device is also used to: after waiting for a set time, obtain the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate at the current moment again; determine whether the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate is within the allowable error range, and when it is not within the allowable error range, continue to adjust the target parameter until the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate is within the allowable error range.

[0089] Corresponding to the above method, the above device further includes a bypass control unit for obtaining a misfire rate of the engine, and when the misfire rate is greater than a preset value, controlling the bypass line to bypass the post-treatment catalyst.

[0090] Corresponding to the above-mentioned device, the present application also discloses a natural gas engine, which can be equipped with any of the above-mentioned natural gas engine after-treatment catalyst aging rate control devices, and the natural gas engine after-treatment catalyst aging rate control device is integrated into an engine controller or a vehicle controller.

[0091] Corresponding to the above-mentioned natural gas engine, the present application also discloses a car, which is equipped with the above-mentioned natural gas engine. The car can be an engineering car or a family car.

[0092] For the convenience of description, the above system is described as being divided into various modules according to their functions. Of course, when implementing the present invention, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0093] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0094] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0095] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0096] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0097] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the aging rate of a natural gas engine after-treatment catalyst, characterized in that: include: Target data under the current engine operating condition is acquired using an aging model to obtain a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition. The aging model is a model constructed based on the Arrhenius equation for calculating the theoretical oxygen storage capacity decrease rate of the engine. Determining whether the current operating condition of the engine is a strong transient operating condition, wherein the strong transient operating condition refers to a transient operating condition in which the fluctuation amplitude of the engine system parameter per unit time is greater than a calibrated value; When the current operating condition of the engine is a strong transient condition: Obtaining an actual oxygen storage capacity decrease rate of the post-treatment catalyst corresponding to the current operating condition; When the actual oxygen storage amount decrease rate is greater than the theoretical oxygen storage amount decrease rate, a probability value of the engine experiencing a high methane operating condition is calculated based on the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, wherein the greater the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, the higher the probability value; When the probability value exceeds a target threshold, the target parameter of the engine is adjusted to reduce the actual oxygen storage amount decrease rate.

2. The method for controlling the aging rate of a natural gas engine post-treatment catalyst according to claim 1, characterized in that: After adjusting the target parameters of the engine, the method further includes: After waiting for the set time, the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate at the current moment are obtained again; Determine whether the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate is within an allowable error range. When it is not within the allowable error range, continue to adjust the target parameter until the difference between the actual oxygen storage capacity decrease rate and the theoretical oxygen storage capacity decrease rate is within the allowable error range.

3. The method for controlling the aging rate of a natural gas engine post-treatment catalyst according to claim 1, characterized in that: The determining whether the current operating condition of the engine is a strong transient operating condition includes: Obtaining at least one engine operating parameter of the engine under the current operating condition, including the speed, load rate, EGR rate, throttle opening, intake pressure, lambda, throttle and ignition angle; Based on the acquired engine operating parameters, it is determined whether the current operating condition of the engine is a strong transient operating condition.

4. The method for controlling the aging rate of a natural gas engine post-treatment catalyst according to claim 1, characterized in that: The aging model is used to obtain target data under the current operating condition of the engine, and the theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition is obtained, including: A reaction temperature of the after-treatment catalyst under the current operating condition and a duration of the current operating condition are obtained, and the reaction temperature and the duration are input into an aging model to calculate a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition through the aging model.

5. The method for controlling the aging rate of a natural gas engine post-treatment catalyst according to claim 4, characterized in that: The reaction temperature and the duration are input into an aging model, comprising: Correcting the reaction temperature and duration based on the correction parameter; The corrected reaction temperature and duration are input into the aging model.

6. The method for controlling the aging rate of a natural gas engine post-treatment catalyst according to claim 1, characterized in that: After determining that the current operating condition of the engine is a strong transient operating condition, and before obtaining the actual oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition, the method further includes: Obtain the cumulative statistical time that the after-treatment catalyst is in a strong transient operating condition during its current life cycle. When the cumulative statistical time reaches a preset statistical time, execute the steps of: obtaining an actual oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition and subsequent steps.

7. The method for controlling the aging rate of a natural gas engine post-treatment catalyst according to claim 1, characterized in that: Also includes: A misfire rate of the engine is obtained, and when the misfire rate is greater than a preset value, a bypass line is controlled to bypass the post-treatment catalyst.

8. A natural gas engine after-treatment catalyst aging rate control device, characterized in that: include: an operating condition identification unit, configured to determine whether the current operating condition of the engine is a strong transient operating condition, and trigger the actual oxygen storage capacity decrease rate acquisition unit, the probability value calculation unit, and the parameter adjustment unit when the engine is in the strong transient operating condition. The strong transient operating condition refers to a transient operating condition in which the fluctuation amplitude of the engine system parameter per unit time is greater than a calibrated value; a theoretical oxygen storage capacity decrease rate calculation unit, configured to acquire target data under a current engine operating condition using an aging model to obtain a theoretical oxygen storage capacity decrease rate of the after-treatment catalyst corresponding to the current operating condition, wherein the aging model is a model constructed based on the Arrhenius equation for calculating the theoretical oxygen storage capacity decrease rate of the engine; an actual oxygen storage amount decrease rate acquisition unit, configured to acquire an actual oxygen storage amount decrease rate of the post-treatment catalyst corresponding to the current operating condition; a probability value calculation unit, configured to calculate, when the actual oxygen storage amount decrease rate is greater than the theoretical oxygen storage amount decrease rate, a probability value of the engine experiencing a high methane operating condition based on a difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, wherein the greater the difference between the actual oxygen storage amount decrease rate and the theoretical oxygen storage amount decrease rate, the higher the probability value; A parameter adjustment unit is used to adjust the target parameter of the engine when the probability value exceeds a target threshold value, so as to reduce the actual oxygen storage capacity decrease rate.

9. A natural gas engine, characterized in that: The device comprises the natural gas engine after-treatment catalyst aging rate control device according to claim 8, wherein the natural gas engine after-treatment catalyst aging rate control device is integrated into an engine controller or a vehicle controller.

10. An automobile, characterized in that: Including the natural gas engine according to claim 9.

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