Engine control method

Abstract

The invention provides an engine control method, and belongs to the technical field of engine control, and the engine control method comprises the following steps: adjusting a target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate in response to the fact that an air-fuel ratio is judged to be abnormal by using a sensor; the air-fuel ratio abnormity at least comprises that the change amplitude of the air-fuel ratio from small to large exceeds a first preset threshold value; in response to the time for which the actual exhaust gas recirculation rate remains at the second exhaust gas recirculation rate exceeding the stabilization time, the target exhaust gas recirculation rate is adjusted to the first exhaust gas recirculation rate for the actual exhaust gas recirculation rate to reach the first exhaust gas recirculation rate. According to the method, the target exhaust gas recirculation rate is increased through abnormal triggering, the exhaust gas recirculation rate is recovered after stabilization, and the emission influence caused by the fact that the air-fuel ratio is changed from over-rich to over-lean is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and in particular to an engine control method. Background Art

[0002] Exhaust gas recirculation (EGR) technology for internal combustion engines, a key means of reducing nitrogen oxide (NOx) emissions, has been widely adopted in engine control. Its core principle is to reintroduce some exhaust gas into the cylinder, lowering combustion temperatures and suppressing NOx formation. The higher the exhaust gas recirculation rate (EGR rate), the greater the volume occupied by exhaust gas and the smaller the volume occupied by fresh air. Calculating the target EGR rate is a crucial component of EGR control, directly determining the accuracy and effectiveness of high-pressure EGR control. However, traditional target EGR rates are primarily calculated using static parameters, making them difficult to adapt to drastic changes under transient operating conditions. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art and proposes an engine control method.

[0004] In a first aspect, an embodiment of the present invention provides an engine control method, comprising: in response to determining an air-fuel ratio abnormality using a sensor, adjusting a target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate; the air-fuel ratio abnormality at least includes a change in the air-fuel ratio from small to large exceeding a first preset threshold; in response to the actual exhaust gas recirculation rate remaining at the second exhaust gas recirculation rate for a time exceeding a stabilization time, adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate so that the actual exhaust gas recirculation rate reaches the first exhaust gas recirculation rate.

[0005] According to an embodiment of the present disclosure, determining an air-fuel ratio abnormality using a sensor includes: detecting a fuel equivalence ratio using a sensor; the sensor includes at least a linear oxygen sensor; determining that the air-fuel ratio is abnormal in response to the fuel equivalence ratio satisfying an air-fuel ratio abnormality condition; wherein the air-fuel ratio abnormality condition includes at least the first target fuel equivalence ratio of the previous sampling cycle being greater than the second preset threshold, the second target fuel equivalence ratio of the current sampling cycle being less than the third preset threshold, and the difference between the first target fuel equivalence ratio and the second target fuel equivalence ratio being less than a fourth preset threshold.

[0006] According to an embodiment of the present disclosure, the target exhaust gas recirculation rate is adjusted from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate, including: calculating an exhaust gas recirculation rate offset rate based on engine parameters; the engine parameters include at least engine speed, the target exhaust gas recirculation rate of the previous sampling period, the change in the target fuel equivalence ratio between the previous sampling period and the current sampling period, the fuel equivalence ratio deviation and one of the first self-learning coefficients; and calculating the second exhaust gas recirculation rate using the exhaust gas recirculation rate offset rate and the first exhaust gas recirculation rate.

[0007] According to an embodiment of the present disclosure, a method for updating the first self-learning coefficient of the exhaust gas recirculation rate offset rate includes: in response to the exhaust gas recirculation rate deviation exceeding a fifth preset threshold value, the first self-learning coefficient is subtracted by the first preset value to serve as the first self-learning coefficient of the next sampling period; the exhaust gas recirculation rate deviation is calculated by the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; in response to the exhaust gas recirculation rate deviation not exceeding the sixth preset threshold value, the first self-learning coefficient is added to the second preset value to serve as the first self-learning coefficient of the next sampling period; in response to the stabilization time being less than the first preset time, the first self-learning coefficient remains unchanged to serve as the first self-learning coefficient of the next sampling period; the first preset time is determined based on the time when the exhaust gas flows from the exhaust gas recirculation valve to the cylinder.

[0008] According to an embodiment of the present disclosure, the time during which the actual exhaust gas recirculation rate is maintained at the second exhaust gas recirculation rate exceeds the stabilization time, which also includes: calculating the stabilization time, specifically including: calculating the initial stabilization time using the transient operating coefficient and the target offset; the transient operating coefficient is determined by the engine speed and the intake pressure fluctuation rate; the target offset is the difference between the first exhaust gas recirculation rate and the second exhaust gas recirculation rate; and adjusting the initial stabilization time using the fresh air intake volume change rate, the actual ignition angle efficiency change, and the second self-learning coefficient to obtain the final stabilization time.

[0009] According to an embodiment of the present disclosure, the exhaust gas recirculation rate deviation is calculated by the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; the updating method of the second self-learning coefficient of the stabilization time includes: in response to the exhaust gas recirculation rate deviation within a preset number of sampling periods being less than the thirteenth preset threshold value and the difference between the final stabilization time and the initial stabilization time is less than the seventh preset threshold value, the second self-learning coefficient is added with the third preset value to be used as the second self-learning coefficient for the next sampling period; in response to the time that the exhaust gas recirculation rate deviation is greater than the ninth preset threshold value for more than the second preset time and the difference between the final stabilization time and the initial stabilization time is greater than the seventh preset threshold value, the second self-learning coefficient is subtracted with the fourth preset value to be used as the second self-learning coefficient for the next sampling period.

[0010] According to an embodiment of the present disclosure, the target exhaust gas recirculation rate is adjusted to the first exhaust gas recirculation rate, including: judging whether the current sampling period meets the exit condition based on the exhaust gas recirculation rate deviation and the target fuel equivalence ratio of the current sampling period; the exhaust gas recirculation rate deviation is calculated by the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; the exit condition is used to characterize the exhaust gas recirculation rate fluctuation and the air-fuel ratio change; if not, the target exhaust gas recirculation rate is adjusted according to the first preset rate; the first preset rate is determined according to the ratio of the outlet pressure to the inlet pressure of the exhaust gas recirculation valve; if so, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate.

[0011] According to an embodiment of the present disclosure, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate, including: in response to satisfying the first exit condition, adjusting the target exhaust gas recirculation rate at a second preset rate; in response to the difference between the target exhaust gas recirculation rate and the actual exhaust gas recirculation rate being less than the twelfth preset threshold, directly adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate; the first exit condition includes the exhaust gas recirculation rate deviation being between the eighth preset threshold and the tenth preset threshold and the target fuel equivalence ratio exceeding the eleventh preset threshold; in response to satisfying the second exit condition, directly adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate; the second exit condition includes the exhaust gas recirculation rate deviation exceeding the tenth preset threshold and the target fuel equivalence ratio exceeding the eleventh preset threshold.

[0012] According to an embodiment of the present disclosure, a method for calculating an exhaust gas recirculation rate deviation includes: using the original exhaust gas recirculation rate deviation and a coefficient to calculate a filtered exhaust gas recirculation rate deviation; wherein the coefficient is calculated as follows: testing to obtain a test coefficient for a preset number of cylinders and a preset speed; and calculating the actual coefficient based on the actual number of cylinders and the actual speed of the engine.

[0013] In a second aspect, the present invention also provides an engine control system, which can be used to implement the above method, and the system includes: an adjustment module, which is used to adjust the target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate in response to the air-fuel ratio being determined to be abnormal by a sensor; the air-fuel ratio abnormality at least includes the change amplitude of the air-fuel ratio from small to large exceeding a first preset threshold; a transition module, which is used to adjust the target exhaust gas recirculation rate to the first exhaust gas recirculation rate in response to the time when the actual exhaust gas recirculation rate remains at the second exhaust gas recirculation rate exceeding the stabilization time, so that the actual exhaust gas recirculation rate reaches the first exhaust gas recirculation rate.

[0014] The engine control method provided by this invention increases the target EGR rate when the air-fuel ratio changes dramatically (from too rich to too lean). Once the engine transition is smooth, the target EGR rate is then reduced to ensure stable combustion and restart emissions optimization. This dynamic adjustment of the target EGR rate overcomes the difficulty of traditional target EGR rate calculation in transient operating conditions, achieving the technical effect of reducing the impact of excessive emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of an engine control method provided by an embodiment of the present invention;

[0016] Figure 2 A schematic diagram of a system structure with EGR provided in an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of a flow chart for determining an abnormal air-fuel ratio using a sensor according to an embodiment of the present invention;

[0018] Figure 4 A schematic diagram of a flow chart for adjusting a target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate provided in an embodiment of the present invention;

[0019] Figure 5 A schematic flow chart of a method for updating a first self-learning coefficient of an exhaust gas recirculation rate offset rate provided by an embodiment of the present invention;

[0020] Figure 6 A schematic diagram of a flow chart for calculating stabilization time according to an embodiment of the present invention;

[0021] Figure 7 A schematic flow chart of a method for updating a second self-learning coefficient of a stabilization time according to an embodiment of the present invention;

[0022] Figure 8 A schematic diagram of a flow chart for adjusting a target exhaust gas recirculation rate to a first exhaust gas recirculation rate provided in an embodiment of the present invention;

[0023] Figure 9 A schematic diagram of a flow chart for directly adjusting a target exhaust gas recirculation rate to a first exhaust gas recirculation rate provided in an embodiment of the present invention;

[0024] Figure 10 This is a structural block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding. These details should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0026] In the absence of conflict, the various embodiments of the present invention and the various features therein may be combined with each other.

[0027] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0028] The terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and / or "made of" are used in this specification, the presence of the features, wholes, steps, operations, elements and / or components is specified, but the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof is not excluded. Similar words such as "connected" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0029] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly defined as such herein.

[0030] In the technical solution of the present invention, the collection, storage, use, processing, transmission, provision and disclosure of user personal information involved are in compliance with the provisions of relevant laws and regulations and do not violate public order and good morals. The use of user data in this technical solution complies with relevant national laws and regulations (for example, the "Information Security Technology Personal Information Security Specification", etc.). For example: corresponding prescribed measures are taken to control access to personal information; the display of personal information is subject to prescribed restrictions; the purpose of using personal information does not exceed the scope of direct or reasonable connection; when using personal information, clear identity reference is eliminated to avoid precise positioning of specific individuals.

[0031] Figure 2 A schematic diagram of a system structure with EGR is provided in an embodiment of the present invention, as shown in FIG. Figure 2 As shown, it includes: air filter 1; mixing valve 2; compressor 3; throttle 4; engine 5; turbine 6; catalyst 7; particulate matter trap 8; EGR cooler 9; EGR valve 10; temperature sensor 11; and differential pressure sensor 12. The specific system structure includes: air filter 1; mixing valve 2 connected to the air filter, used to adjust the pressure at the outlet of EGR valve 10 and increase the pressure difference between the two ends of EGR valve 10, with two air flow paths extending from the mixing valve 2; compressor 3 connected to one of the air flow paths of mixing valve 2; throttle 4 connected to compressor 3; engine 5 connected to throttle 4, used to compress fresh air for supercharging; turbine 6 connected to engine 5, used to control the opening of the exhaust bypass valve; catalyst 7 connected to turbine 6; particulate matter trap 8 connected to catalyst 7. ; The EGR cooler 9 installed on the other air flow path of the mixing valve 2 is used to receive the exhaust gas output by the particulate matter collector 8 and cool it to increase the exhaust gas flow rate; one end is connected to the EGR cooler 9, and the other end is connected to the EGR valve 10 of the mixing valve 2, which is used to control the exhaust gas flow entering the cylinder; the temperature sensor 11 installed between the EGR valve 10 and the EGR cooler 9 is used to detect the exhaust gas temperature entering the EGR valve 10; the pressure difference sensor 12 connected to the EGR valve 10 is used to detect the pressure at the inlet and outlet of the EGR valve 10.

[0032] Furthermore, if the oxygen concentration in the exhaust pipe is too low, it is called "too rich"; if the oxygen concentration in the exhaust pipe is too high, it is called "too lean"; the concentration of air in the exhaust pipe is determined by the excess air coefficient. The reciprocal of the fuel equivalence ratio The actual fuel equivalence ratio (actual FEQR) can be reflected by the linear oxygen sensor:

[0033]

[0034] Then the target air-fuel ratio can be set by setting the target To achieve this, the target fuel equivalence ratio is as follows:

[0035]

[0036] The present invention mainly solves the problem of changing the target FEQR from greater than 1 (too rich) in the previous sampling period to less than 1 (too lean) in the current sampling period. The sampling period in this example is a fixed time. In this example, the target EGR rate optimization control method is taken as 10ms, that is, the process of the air-fuel ratio changing from small to large.

[0037] "Actual fuel" refers to the actual amount of fuel entering the cylinder per unit time, "actual air" refers to the actual amount of fresh air entering the cylinder per unit time, "target fuel" refers to the target amount of fuel entering the cylinder per unit time, "target air" refers to the target amount of fresh air entering the cylinder per unit time, "ideal air" refers to the ideal amount of fresh air entering the cylinder per unit time, and "ideal fuel" refers to the ideal amount of fuel entering the cylinder per unit time. "Target" is not the same as "ideal." The target value can be actively adjusted based on engine operating conditions, but the ideal value is determined by the fuel quality.

[0038] When the engine is cut off from fuel, is 0; when “too rich”, Greater than 1; when "too thin", Less than 1; When it is equal to 1, the current air-fuel ratio is ideal ( Equal to 1 means that the ratio of the actual air volume to the actual fuel volume is equal to the ratio of the ideal air volume to the ideal fuel volume. In this example, the ideal air-fuel ratio is 14.3).

[0039] Exhaust Gas Recirculation (EGR) draws exhaust gas from the exhaust system and recirculates it into the intake system. Research has shown that EGR systems offer advantages in improving emissions, reducing fuel consumption, and improving anti-knock performance. EGR control is optimized to minimize emissions impacts when the engine's air-fuel ratio changes from rich to lean.

[0040] In the related art, the target EGR rate is mainly calculated based on static parameters (speed, load), but the EGR rate response lags when the operating conditions change rapidly and cannot adapt to transient conditions. At the same time, there is a lack of quantitative control of the air-fuel ratio change. To solve at least one of the technical problems existing in the above related art, Figure 1 A flow chart of an engine control method provided by an embodiment of the present invention is shown as follows: Figure 1 As shown, an embodiment of the present invention provides an engine control method, comprising: in response to determining an air-fuel ratio abnormality using a sensor, adjusting a target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate; the air-fuel ratio abnormality at least includes a change in the air-fuel ratio from a small to a large value exceeding a first preset threshold value (i.e., the fuel equivalence ratio changes from greater than 1 (too rich) in the previous sampling period to less than 1 (too lean) in the current sampling period, and the sampling period in this example is a fixed time). In response to the time for which the actual exhaust gas recirculation rate remains at the second exhaust gas recirculation rate exceeding the stabilization time, the target exhaust gas recirculation rate is adjusted to the first exhaust gas recirculation rate so that the actual exhaust gas recirculation rate reaches the first exhaust gas recirculation rate.

[0041] In this embodiment, the first exhaust gas recirculation rate The calculation method is as follows: determine the basic target EGR rate based on the fuel consumption and engine combustion stability evaluation indicators; obtain the corresponding correction rate based on special operating conditions; determine the initial target EGR rate based on the basic target EGR rate and each correction rate; the initial target EGR rate is the product of the basic target EGR rate and each correction rate; determine whether EGR is activated based on the EGR activation state conditions; divide the EGR state according to the judgment result and determine the final target EGR rate. The special operating conditions are as follows: (1) When the throttle is close to full open, the pressure difference before and after the throttle is small, and there is a great uncertainty in the estimation accuracy of the gas volume controlled by the compressed gas equation method. It is necessary to reduce the basic target EGR rate; (2) When the exhaust manifold pressure is close to the intake manifold pressure, the EGR exhaust gas flow is extremely small, the gas volume is unstable, and exhaust gas backflow is avoided. It is necessary to reduce the basic target EGR rate; (3) When the engine is close to the minimum ignition angle, the engine combustion stability is poor, and it is necessary to reduce the basic target EGR rate.

[0042] In this embodiment, it is first determined whether to adjust the target EGR rate. If yes, proceed to the next step, otherwise stop updating the target EGR rate; adjust the target EGR rate and stabilization time; and determine the final target EGR rate.

[0043] In this embodiment, the first preset threshold value of the air-fuel ratio can be directly set as a preset parameter, or the change of the air-fuel ratio can be standardized by the change of the fuel equivalence ratio.

[0044] According to the embodiment of the present disclosure, when the air-fuel ratio changes from too rich to too lean, the operating condition may be to rapidly increase the exhaust temperature, etc. At this time, NOx is easily generated. Under certain conditions, the target EGR rate is set to three actions: (1) first increase the target EGR rate to the second exhaust gas recirculation rate; (2) stabilize the target EGR rate for a period of time; (3) weight the target EGR rate and the original first exhaust gas recirculation rate to form the final target EGR rate. This solves the problem of delayed response of traditional EGR control. When the air-fuel ratio changes from too rich to too lean quickly, the EGR rate is increased to avoid the risks caused by the change of mixture concentration. After the engine stabilizes, the EGR rate is reduced again to optimize emissions. When the air-fuel ratio changes from too rich to too lean, the target EGR rate is controlled and optimized to improve emissions.

[0045] Based on the above embodiments, Figure 3 A flow chart of determining an abnormal air-fuel ratio using a sensor according to an embodiment of the present invention is provided. Figure 3As shown, using a sensor to determine air-fuel ratio abnormality includes: using a sensor to detect the fuel equivalence ratio; the sensor includes at least a linear oxygen sensor; in response to the fuel equivalence ratio satisfying the air-fuel ratio abnormality condition, determining that the air-fuel ratio is abnormal; wherein the air-fuel ratio abnormality condition includes at least the first target fuel equivalence ratio of the previous sampling cycle is greater than the second preset threshold, the second target fuel equivalence ratio of the current sampling cycle is less than the third preset threshold, and the difference between the first target fuel equivalence ratio and the second target fuel equivalence ratio is less than the fourth preset threshold.

[0046] In this embodiment, it is first determined whether the conditions are met. Subsequent actions are allowed only after all the following conditions are met. Otherwise, the EGR rate adjustment is not performed. The entry conditions are as follows: (1) The target FEQR of the previous sampling period (the sampling period in this example is 10ms) Exceeds the preset value, which is 1.1 in this example; (2) Target FEQR for this sampling period Not exceeding the preset value, which is 0.9 in this example; (3) Target FEQR change Not exceeding the preset value. In this example, -0.3 is used. Since the target FEQR of this sampling period is less than the target FEQR of the previous sampling period, the preset threshold is a negative value. is the FEQR change, which is the target FEQR for this sampling period Subtract the target FEQR of the previous sampling period ,Right now .

[0047] In this embodiment, once the conditions for entering the target EGR rate adjustment process are met, the target EGR rate adjustment process that has already started needs to be completed even if the parameter (fuel equivalence ratio) changes and causes the entry conditions to not be met in the next sampling period.

[0048] Through the embodiments of the present disclosure, false triggering is avoided by combining and judging the target FEQR of the previous sampling period, the target FEQR of the next sampling period, and the target FEQR variation between the two periods using thresholds.

[0049] Based on the above embodiments, Figure 4 A flow chart of adjusting the target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate is provided in an embodiment of the present invention, as shown in FIG. Figure 4The target exhaust gas recirculation rate is adjusted from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate, including: calculating an exhaust gas recirculation rate offset rate based on engine parameters; the engine parameters include at least engine speed, the target exhaust gas recirculation rate of the previous sampling cycle, the change in the target fuel equivalence ratio between the previous sampling cycle and the current sampling cycle, the fuel equivalence ratio deviation and one of the first self-learning coefficient; using the exhaust gas recirculation rate offset rate and the first exhaust gas recirculation rate to calculate the second exhaust gas recirculation rate.

[0050] In this embodiment, the calculation process of the second waste recycling rate is as follows, and this step is performed for only one sampling cycle:

[0051] Increase the target EGR rate to a certain value, that is, determine the EGR rate change and EGR rate deviation rate (Within the range of 0 to C2, C2 is set to 0.3 in this example to avoid excessive changes in the EGR rate):

[0052] .

[0053] in, is the engine speed; is the final target EGR rate in the previous sampling period, that is, the final target EGR rate, that is, the final target EGR rate The value of the previous sampling period; is the FEQR deviation; is the FEQR change; The EGR rate offset rate self-learning coefficient (i.e., the first self-learning coefficient) has a default value of 0. It can be saved after the vehicle is powered off and can be continuously updated through self-learning. This section will be described later. is the base value of the EGR rate deviation rate, is the EGR rate deviation correction factor, and its two calibrations are obtained from the bench emission calibration to ensure the best emission data.

[0054] in, in, is the target of this sampling period, is the target of the previous sampling period.

[0055] in, ,in, is the actual FEQR of the current sampling period, is the actual FEQR of the previous sampling period.

[0056] In this embodiment, the calculation is After that, the second exhaust gas recirculation rate can be solved, and the calculation formula is as follows:

[0057]

[0058] in, is the first exhaust gas recirculation rate.

[0059] According to the embodiment of the present disclosure, the purpose of increasing the target EGR rate is to improve the generation of NOx by increasing the target EGR rate.

[0060] Based on the above embodiments, Figure 5 A flow chart of a method for updating the first self-learning coefficient of the exhaust gas recirculation rate offset rate provided by an embodiment of the present invention is shown as follows: Figure 5 As shown, the method for updating the first self-learning coefficient of the exhaust gas recirculation rate offset rate includes: in response to the exhaust gas recirculation rate deviation exceeding the fifth preset threshold, the first self-learning coefficient is subtracted from the first preset value to serve as the first self-learning coefficient of the next sampling period; the exhaust gas recirculation rate deviation is calculated by the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; in response to the exhaust gas recirculation rate deviation not exceeding the sixth preset threshold, the first self-learning coefficient is added to the second preset value to serve as the first self-learning coefficient of the next sampling period; in response to the stabilization time being less than the first preset time, the first self-learning coefficient remains unchanged to serve as the first self-learning coefficient of the next sampling period; the first preset time is determined according to the time when the exhaust gas flows from the exhaust gas recirculation valve to the cylinder.

[0061] In this embodiment, the EGR rate deviation rate self-learning coefficient The determination method is as follows: Read the During this time, the self-learning coefficient is updated according to the following method:

[0062] (1) If the stabilization time is less than the time , then , Get the EGR rate offset rate self-learning coefficient learned last time.

[0063] (2) EGR rate deviation If the fluctuation exceeds the preset value, in this example, ±0.015, then .

[0064] (3) EGR rate deviation The fluctuation does not exceed the preset value, in this example, ±0.01, then .

[0065] (4) In other cases, .

[0066] In this embodiment, the self-learning coefficient update is completed and then executed again in the next driving cycle of the vehicle.

[0067] Through the embodiments of the present disclosure, corresponding update methods are provided for large deviations and small deviations respectively, and learning is stopped when the stabilization time is insufficient. The self-learning coefficient is dynamically updated according to the EGR rate deviation, thereby improving the calculation accuracy of the second exhaust gas recirculation rate.

[0068] Based on the above embodiments, Figure 6 A flow chart of calculating the stabilization time according to an embodiment of the present invention is shown in FIG. Figure 6 As shown, the time during which the actual exhaust gas recirculation rate remains at the second exhaust gas recirculation rate exceeds the stabilization time, and the process also includes: calculating the stabilization time, specifically including: calculating the initial stabilization time using the transient operating coefficient and the target offset; the transient operating coefficient is determined by the engine speed and the intake pressure fluctuation rate; the target offset is the difference between the first exhaust gas recirculation rate and the second exhaust gas recirculation rate; and adjusting the initial stabilization time using the fresh air intake volume change rate, the actual ignition angle efficiency change, and the second self-learning coefficient to obtain the final stabilization time.

[0069] In this embodiment, the default stabilization time is first obtained. , where EGR rate offset ; is the transient operating coefficient, The engine speed n and the intake pressure fluctuation rate It is jointly determined and represents the changes in the transient operating conditions of the engine. The larger the value, the more volatile the engine operating conditions. Its value is limited to 0-1. The calibration basis is that within the time t1 after entering the stabilization phase and exiting the stabilization phase (t1 is equal to ), target EGR rate and actual EGR rate difference The fluctuation of (EGR rate deviation) is within the preset range. The time it takes for exhaust gas to flow from the EGR valve to the cylinder is obtained through bench calibration. This part can be used for different engine speeds. and different actual intake air densities entering the cylinder Under different EGR rates, the average value of multiple sampling data is obtained. The engine speed and the actual intake density entering the cylinder Definitely got it.

[0070] Further, Take the data before the last N sampling periods (single sampling period is 10ms) The difference between the maximum and minimum values ​​of N is related to engine speed. Lower speeds result in smaller N values, while higher speeds result in larger N values. This is mainly because lower speeds lead to more pronounced intake pressure fluctuations, and larger sampling cycles make it less likely to accurately reflect transient operating conditions. The relationship between N and engine speed is shown in Table 1.

[0071] Table 1

[0072]

[0073] in, is the throttle outlet intake pressure, is the throttle outlet intake pressure of the Nth sampling period, is the throttle outlet intake pressure after first-order low-pass filtering, is the filtered throttle outlet intake pressure of the Nth sampling period.

[0074]

[0075] in, is the filtered throttle outlet intake pressure of the N-1th sampling period, N=1,2,3…; Equal to the throttle outlet intake pressure at the 0th sampling cycle ; Sampling period interval In this example, it is 10ms. is the coefficient: (The number of engine cylinders in this example is 4, The calibration speed is 1000rpm. The purpose of this setting is to normalize the process. Under different cylinder numbers and speeds, no special calibration is required. Only the 4-cylinder engine and the speed of 1000rpm need to be calibrated. , thereby reducing the calibration test work), where m is the number of engine cylinders, n is the engine speed, is the throttle outlet intake pressure filter coefficient, which is 0.02 in this example. The query table is shown in Table 2.

[0076] Table 2

[0077]

[0078] In the above table data, the transient operating coefficient change rate is limited to no more than ±0.1 / 10ms, and the final transient operating coefficient is obtained. .

[0079] If the stabilization phase is not exited, the rate of change of fresh air intake volume based on the stabilization phase and actual ignition angle efficiency change The stabilization time is updated and optimized. The purpose of this consideration is to reduce the deterioration of NOx suppression during the stabilization phase.

[0080] Fresh air intake rate of change The difference between the current mass flow of fresh air entering the cylinder during the stabilization phase and the mass flow of fresh air entering the cylinder just after entering the stabilization phase is obtained by dividing the difference by the mass flow of fresh air entering the cylinder just after entering the stabilization phase.

[0081] Actual ignition angle efficiency change The difference between the current actual ignition angle efficiency in the stabilization phase and the actual ignition angle efficiency just after entering the stabilization phase is obtained.

[0082] In this embodiment, the final stabilization time is calculated as follows:

[0083]

[0084] Wherein, t3 is the original remaining time of the stabilization phase, and t3' is the time after correction based on the change rate of the fresh air intake amount and the change of the actual ignition angle efficiency in the stabilization phase. Under the condition of the same change rate of the fresh air intake amount, if the change of the actual ignition angle efficiency is larger, The larger the change rate of the fresh air intake is, the greater the change rate of the fresh air intake is. The smaller. To stabilize the time correction coefficient self-learning coefficient, its default value is 0. It can be saved after the vehicle is powered off and can be continuously updated through self-learning.

[0085] Through the embodiment of the present disclosure, the target setting stage of the first step calculation obtains the optimized target EGR rate Stabilize for a period of time t. The purpose of the stabilization stage is to adjust the EGR rate. If the EGR rate is further adjusted, the working conditions will deteriorate.

[0086] Based on the above embodiments, Figure 7 A flow chart of a method for updating the second self-learning coefficient of the stabilization time provided by an embodiment of the present invention is shown as follows: Figure 7As shown, the method for updating the second self-learning coefficient of the stabilization time includes: in response to the exhaust gas recirculation rate deviation within a preset number of sampling periods being less than a thirteenth preset threshold value and the difference between the final stabilization time and the initial stabilization time being less than a seventh preset threshold value, the second self-learning coefficient is added with a third preset value to be used as the second self-learning coefficient for the next sampling period; the exhaust gas recirculation rate deviation is calculated by the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; in response to the time that the exhaust gas recirculation rate deviation is greater than the ninth preset threshold value for more than a second preset time and the difference between the final stabilization time and the initial stabilization time being greater than the seventh preset threshold value, the second self-learning coefficient is subtracted with a fourth preset value to be used as the second self-learning coefficient for the next sampling period.

[0087] In this embodiment, if the following phenomena occur during the stabilization phase:

[0088] (1) During the stabilization phase, the EGR rate deviation does not exceed the preset value (±0.01 in this example) during 2 consecutive CNT driving cycles (5 in this example), and If it is not greater than the preset value (0.1s in this example), ,in, It is the self-learning coefficient of the stabilization time correction coefficient learned last time. After the self-learning coefficient of the stabilization time correction coefficient is updated, CNT2 is cleared and the stabilization phase is entered in the next driving cycle. If no knock occurs, CNT2 is increased by 1, and it can be increased by 1 at most in each driving cycle. The default value of CNT2 is 0, which can be saved after the vehicle is powered off and can be continuously updated in self-learning.

[0089] (2) The EGR rate deviation exceeds the preset value (±0.015 in this example) during the stabilization phase of the current driving cycle for a continuous period exceeding the preset value (0.03s in this example), and is greater than the preset value (0.1s in this example), then .

[0090] (3) In other cases .

[0091] According to the embodiments of the present disclosure, the self-learning coefficient is updated based on the EGR rate deviation and the change in the stabilization time, thereby preventing the occurrence of excessive EGR rate deviation and the redundant or excessive correction of the stabilization time.

[0092] Based on the above embodiments, Figure 8 A flow chart of adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate provided in an embodiment of the present invention is shown in FIG. Figure 8As shown, the target exhaust gas recirculation rate is adjusted to the first exhaust gas recirculation rate, including: judging whether the current sampling period meets the exit condition according to the exhaust gas recirculation rate deviation and the target fuel equivalence ratio of the current sampling period; the exhaust gas recirculation rate deviation is calculated by the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; the exit condition is used to characterize the fluctuation of the exhaust gas recirculation rate and the change of the air-fuel ratio; if not, the target exhaust gas recirculation rate is adjusted according to the first preset rate; the first preset rate is determined according to the ratio of the outlet pressure to the inlet pressure of the exhaust gas recirculation valve; if so, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate.

[0093] In this embodiment, the target EGR rate Slowly transition to The rate k1 is set to take into account the fluctuation of EGR rate deviation within a preset range, based on the ratio of EGR valve outlet pressure to inlet pressure. The calibration table is shown in Table 3.

[0094] Table 3

[0095]

[0096] According to the embodiments of the present disclosure, when the engine operating condition is stable, the target exhaust gas recirculation rate is gradually adjusted to the initial exhaust gas recirculation rate to optimize emissions.

[0097] Based on the above embodiments, Figure 9 A flow chart of directly adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate provided in an embodiment of the present invention is as follows: Figure 9 As shown, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate, including: in response to the first exit condition being met, the target exhaust gas recirculation rate is adjusted at a second preset rate; in response to the difference between the target exhaust gas recirculation rate and the actual exhaust gas recirculation rate being less than the twelfth preset threshold, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate; the first exit condition includes the exhaust gas recirculation rate deviation being between the eighth preset threshold and the tenth preset threshold and the target fuel equivalence ratio exceeding the eleventh preset threshold; in response to the second exit condition being met, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate; the second exit condition includes the exhaust gas recirculation rate deviation exceeding the tenth preset threshold and the target fuel equivalence ratio exceeding the eleventh preset threshold.

[0098] In this embodiment, if the first exit condition and the second exit condition occur during the execution process, the execution of the transition step is exited.

[0099] In this embodiment, the first exit condition: the final target EGR rate and actual EGR rate The difference exceeds the preset value, which is ±0.03 in this example; the target FEQR of the sampling period Exceeds the preset value, which is 1.15 in this example; if the current state is in step 1 after the above entry conditions are met, then exit through transition and adjust the target exhaust gas recirculation rate to the first exhaust gas recirculation rate , and its transition method is: , k4 in this example is set to 0.1, until and When the difference does not exceed ±0.01 for the first time, = The target EGR rate will be readjusted when the target EGR rate reduction conditions are met again.

[0100] In this embodiment, the second exit condition: the final target EGR rate and actual EGR rate The difference exceeds the preset value, which is ±0.2 in this example; the target FEQR of this sampling period If the target EGR rate exceeds the preset value, in this example, it is 1.15; if the above entry conditions are met and step 2 or 3 is executed, the target EGR rate is directly set to the target EGR rate before optimization. , without any transition. When the target EGR rate reduction conditions are met again later, the target EGR rate will be readjusted.

[0101] Through the embodiments of the present disclosure, soft protrusion is used to prevent EGR rate steps when the difference is small, and hard exit is used to cope with extreme scenarios when the difference is large.

[0102] Based on the above embodiment, the method for calculating the exhaust gas recirculation rate deviation includes: using the original exhaust gas recirculation rate deviation and the coefficient to calculate the filtered exhaust gas recirculation rate deviation; wherein the coefficient is calculated as follows: testing to obtain a test coefficient for a preset number of cylinders and a preset speed; and calculating the actual coefficient based on the actual number of cylinders and the actual speed of the engine.

[0103] In this embodiment, the fluctuation of the EGR rate deviation is determined to be within a preset range based on:

[0104]

[0105] in, is the original EGR rate deviation; is the original EGR rate deviation of the Nth sampling period; is the EGR rate deviation after first-order low-pass filtering; is the EGR rate deviation after filtering in the Nth sampling period; is the filtered EGR rate deviation of the N-1th sampling period, N=1,2,3…; EGR rate deviation at the 0th sampling cycle In particular, the 0th sampling cycle occurs at the first sampling time just after entering the transition phase, and its value is equal to the EGR rate deviation in the previous sampling cycle; the sampling cycle interval is In this example, it is 10ms.

[0106] is the coefficient: (The number of engine cylinders N in this example is 4, The calibration speed is 1000rpm). is the filter coefficient of EGR rate deviation, which is 0.1 in this example.

[0107] exist When all the conditions are met during the transition phase, it means that the fluctuation of EGR rate deviation is within the preset range. In this example, 0.005 is used.

[0108] Through the embodiment of the present disclosure, normalization processing is performed, and no special calibration is required under different cylinder numbers and speeds. It is only necessary to calibrate the 4-cylinder engine and the speed of 1000 rpm. , thereby reducing calibration testing work.

[0109] Based on the same inventive concept, the present invention also provides an engine control system, which can be used to implement the above method. The system includes: an adjustment module, which is used to adjust the target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate in response to the air-fuel ratio being determined to be abnormal by a sensor; the air-fuel ratio abnormality at least includes the change amplitude of the air-fuel ratio from small to large exceeding a first preset threshold; a transition module, which is used to adjust the target exhaust gas recirculation rate to the first exhaust gas recirculation rate in response to the time when the actual exhaust gas recirculation rate remains at the second exhaust gas recirculation rate exceeding the stabilization time, so that the actual exhaust gas recirculation rate reaches the first exhaust gas recirculation rate.

[0110] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device. Figure 10 This is a structural block diagram of an electronic device provided by an embodiment of the present invention. Figure 10 As shown, an embodiment of the present invention provides an electronic device comprising: one or more processors 101, a memory 102, and one or more I / O interfaces 103. The memory 102 stores one or more programs, which, when executed by the one or more processors, enable the one or more processors to implement any of the engine control methods described in the above embodiments. The one or more I / O interfaces 103 are connected between the processors and the memory and are configured to enable information exchange between the processors and the memory.

[0111] Among them, the processor 101 is a device with data processing capabilities, including but not limited to a central processing unit (CPU); the memory 102 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically such as SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory (FLASH); the I / O interface (read-write interface) 103 is connected between the processor 101 and the memory 102, and can realize information interaction between the processor 101 and the memory 102, including but not limited to a data bus (Bus), etc.

[0112] In some embodiments, the processor 101 , the memory 102 , and the I / O interface 103 are connected to each other via a bus 104 , and further connected to other components of the computing device.

[0113] In some embodiments, the one or more processors 101 include a field programmable gate array.

[0114] An embodiment of the present invention further provides a computer-readable medium. The computer-readable medium stores a computer program, wherein when executed by a processor, the program implements the steps of any of the engine control methods described in the above embodiments. The computer-readable storage medium may be volatile or non-volatile.

[0115] An embodiment of the present invention also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code. When the computer-readable code runs in a processor of an electronic device, the processor in the electronic device executes the above-mentioned engine control method.

[0116] Those skilled in the art will appreciate that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, or appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable storage medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transient medium).

[0117] As is known to those skilled in the art, the term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technology, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by a computer. Furthermore, as is known to those skilled in the art, communication media typically embodies computer-readable program instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0118] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions to be stored in the computer-readable storage medium in each computing / processing device.

[0119] The computer program instructions for performing the operations of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, the state information of the computer-readable program instructions is used to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), so that the electronic circuit can execute the computer-readable program instructions, thereby implementing various aspects of the present invention.

[0120] The computer program product described herein may be implemented in hardware, software, or a combination thereof. In one embodiment, the computer program product is implemented as a computer storage medium. In another embodiment, the computer program product is implemented as a software product, such as a software development kit (SDK).

[0121] Various aspects of the present invention are described herein with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer-readable program instructions.

[0122] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device is generated that implements the functions / actions specified in one or more blocks in the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium, where these instructions cause the computer, programmable data processing device, and / or other device to operate in a specific manner. Thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing various aspects of the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

[0123] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operational steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

[0124] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and the part of the module, program segment or instruction includes one or more executable instructions for realizing the logical function of the specification. In some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the function or action of the specification, or can be implemented with a combination of dedicated hardware and computer instructions.

[0125] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for purposes of limitation. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly indicated, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Therefore, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. An engine control method, characterized in that: include: In response to the sensor determining that the air-fuel ratio is abnormal, adjusting the target exhaust gas recirculation rate from the first exhaust gas recirculation rate to the second exhaust gas recirculation rate; the air-fuel ratio abnormality at least includes a change in the air-fuel ratio from small to large exceeding a first preset threshold; In response to the actual EGR rate being maintained at the second EGR rate for a period exceeding a stabilization time, the target EGR rate is adjusted to the first EGR rate so that the actual EGR rate reaches the first EGR rate.

2. The method according to claim 1, wherein The method of determining an abnormal air-fuel ratio by using a sensor includes: The fuel equivalence ratio is detected by using a sensor; the sensor includes at least a linear oxygen sensor; In response to the fuel equivalence ratio satisfying an air-fuel ratio abnormality condition, determining that the air-fuel ratio is abnormal; Among them, the abnormal air-fuel ratio condition includes at least the first target fuel equivalence ratio of the previous sampling cycle is greater than the second preset threshold, the second target fuel equivalence ratio of the current sampling cycle is less than the third preset threshold, and the difference between the first target fuel equivalence ratio and the second target fuel equivalence ratio is less than the fourth preset threshold.

3. The method according to claim 1, wherein The adjusting the target exhaust gas recirculation rate from the first exhaust gas recirculation rate to the second exhaust gas recirculation rate includes: Calculating an exhaust gas recirculation rate deviation rate based on engine parameters; the engine parameters including at least one of an engine speed, a target exhaust gas recirculation rate for a previous sampling period, a change in a target fuel equivalence ratio between a previous sampling period and a current sampling period, a fuel equivalence ratio deviation, and a first self-learning coefficient; A second exhaust gas recirculation rate is calculated using the exhaust gas recirculation rate offset rate and the first exhaust gas recirculation rate.

4. The method according to claim 3, wherein: The method for updating the first self-learning coefficient of the exhaust gas recirculation rate offset rate includes: In response to the exhaust gas recirculation rate deviation exceeding a fifth preset threshold, subtracting a first preset value from the first self-learning coefficient to provide the first self-learning coefficient for the next sampling period; the exhaust gas recirculation rate deviation is calculated as the difference between the actual exhaust gas recirculation rate and the target exhaust gas recirculation rate; In response to the exhaust gas recirculation rate deviation not exceeding a sixth preset threshold, adding a second preset value to the first self-learning coefficient to be used as the first self-learning coefficient for the next sampling period; In response to the stabilization time being less than a first preset time, the first self-learning coefficient remains unchanged to be used as the first self-learning coefficient of the next sampling period; the first preset time is determined according to the time it takes for exhaust gas to flow from the exhaust gas recirculation valve to the cylinder.

5. The method according to claim 1, wherein The time during which the actual exhaust gas recirculation rate is maintained at the second exhaust gas recirculation rate exceeds the stabilization time, and the process further includes: Calculate the stabilization time, including: Calculating an initial stabilization time using a transient operating coefficient determined by the engine speed and the intake pressure fluctuation rate and a target offset that is the difference between the first exhaust gas recirculation rate and the second exhaust gas recirculation rate; The initial stabilization time is adjusted using the fresh air intake amount change rate, the actual ignition angle efficiency change, and the second self-learning coefficient to obtain the final stabilization time.

6. The method according to claim 5, wherein: The method for updating the second self-learning coefficient of the stabilization time includes: In response to an exhaust gas recirculation rate deviation being less than a thirteenth preset threshold value within a preset number of sampling periods and a difference between the final stabilization time and the initial stabilization time being less than a seventh preset threshold value, adding a third preset value to the second self-learning coefficient to be used as the second self-learning coefficient for a next sampling period; the exhaust gas recirculation rate deviation being calculated as a difference between an actual exhaust gas recirculation rate and a target exhaust gas recirculation rate; In response to the time during which the exhaust gas recirculation rate deviation is greater than a ninth preset threshold value exceeding a second preset time and the difference between the final stabilization time and the initial stabilization time is greater than a seventh preset threshold value, a fourth preset value is subtracted from the second self-learning coefficient to be used as the second self-learning coefficient for the next sampling period.

7. The method according to claim 1, wherein The adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate includes: Determining whether the current sampling period meets an exit condition based on the EGR rate deviation and the target fuel equivalence ratio during the current sampling period; the EGR rate deviation is calculated as the difference between the actual EGR rate and the target EGR rate; and the exit condition is used to characterize EGR rate fluctuations and air-fuel ratio changes. If not, adjusting the target exhaust gas recirculation rate according to a first preset rate; the first preset rate is determined according to a ratio of an outlet pressure to an inlet pressure of an exhaust gas recirculation valve; If so, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate.

8. The method according to claim 7, wherein: Directly adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate includes: In response to a first exit condition being satisfied, adjusting the target exhaust gas recirculation rate at a second preset rate; in response to a difference between the target exhaust gas recirculation rate and the actual exhaust gas recirculation rate being less than a twelfth preset threshold, directly adjusting the target exhaust gas recirculation rate to the first exhaust gas recirculation rate; the first exit condition including an exhaust gas recirculation rate deviation being between an eighth preset threshold and a tenth preset threshold and a target fuel equivalence ratio exceeding an eleventh preset threshold; In response to satisfying a second exit condition, the target exhaust gas recirculation rate is directly adjusted to the first exhaust gas recirculation rate; the second exit condition includes that the exhaust gas recirculation rate deviation exceeds a tenth preset threshold and the target fuel equivalence ratio exceeds an eleventh preset threshold.

9. The method according to claim 7, wherein: The method for calculating the exhaust gas recirculation rate deviation includes: Calculate the filtered exhaust gas recirculation rate deviation using the original exhaust gas recirculation rate deviation and the coefficient; The coefficient is calculated as follows: The test coefficients of the preset number of cylinders and the preset speed are obtained by testing; The actual coefficient is calculated based on the actual number of cylinders and actual speed of the engine.

10. An engine control system, characterized in that: The system can be used to implement the method according to any one of claims 1 to 9, and the system includes: an adjustment module configured to adjust the target exhaust gas recirculation rate from a first exhaust gas recirculation rate to a second exhaust gas recirculation rate in response to a determination by the sensor that the air-fuel ratio is abnormal; the abnormal air-fuel ratio at least comprising a change in the air-fuel ratio from a small value to a large value exceeding a first preset threshold; The transition module is configured to adjust the target exhaust gas recirculation rate to the first exhaust gas recirculation rate in response to the actual exhaust gas recirculation rate being maintained at the second exhaust gas recirculation rate for a period exceeding a stabilization time, so that the actual exhaust gas recirculation rate reaches the first exhaust gas recirculation rate.

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