Air-fuel ratio control method, system, equipment and medium

Abstract

The invention discloses an air-fuel ratio control method, system, equipment and medium, and relates to the technical field of data processing, and the method comprises the following steps: obtaining a front oxygen sensor and a rear oxygen sensor, obtaining two historical monitoring periods, obtaining a front oxygen ion concentration voltage sequence according to the front oxygen sensor, and obtaining a rear oxygen ion concentration voltage sequence according to the rear oxygen sensor; a front oxygen stability index is obtained, whether the front oxygen stability index is lower than a first preset threshold value or not is judged, if yes, a rear oxygen steady-state interval is obtained based on the front oxygen stability index, and a rear oxygen stability index is obtained; whether the post-oxygen stability index is higher than a second preset threshold value or not is judged, if yes, a current front oxygen ion concentration voltage value and a current post-oxygen ion concentration voltage value at the current moment are collected based on a front oxygen sensor and a post oxygen sensor, and the current air-fuel ratio is obtained; and the oil nozzle control compensation proportion is obtained according to the current air-fuel ratio and the standard air-fuel ratio. The method has the advantages of stable and reliable control, dynamic self-adaption and good data processing effect.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, and specifically to an air-fuel ratio control method, system, device, and medium. Background Technology

[0002] In the field of air-fuel ratio control of internal combustion engines, existing methods rely on the real-time voltage signals of the front oxygen sensor (installed between the exhaust manifold and the three-way catalytic converter) and the rear oxygen sensor (installed after the three-way catalytic converter) to perform closed-loop regulation of the air-fuel ratio.

[0003] However, existing air-fuel ratio control methods have the following drawbacks: While the front oxygen sensor responds quickly, its voltage signal fluctuates violently due to exhaust gas disturbances during sudden engine operating conditions (such as rapid acceleration / deceleration), generating high-frequency noise. Although the rear oxygen sensor is more stable due to the filtering effect of the three-way catalytic converter, its response lag is significant. Both sensors are prone to distortion in single-sample values ​​under dynamic conditions. If directly used for air-fuel ratio calculation, this will lead to incorrect fuel injection quantity compensation, resulting in an overly rich or lean mixture. Furthermore, the steady-state reference voltage range of the rear oxygen sensor is usually fixed based on bench calibration. In actual operation, due to changes in engine stability, continuing to use a fixed range will lead to misjudgment of the rear oxygen signal (e.g., normal voltage is identified as abnormal), thus incorrectly triggering air-fuel ratio correction. Furthermore, single-cycle data has weak anti-interference capability. Existing methods mostly rely on sensor data at the current moment or a single monitoring cycle. When occasional electromagnetic interference, exhaust pulsation, or instantaneous sensor malfunctions produce abnormal voltage spikes, these may be misjudged as a true air-fuel ratio deviation, causing oscillatory adjustment of the fuel injection pulse width, disrupting combustion stability and increasing emissions. Summary of the Invention

[0004] In view of the technical problems described in the background art, the present invention provides an air-fuel ratio control method, system, device and medium.

[0005] An air-fuel ratio control method includes: acquiring a pre-oxygen sensor located between the exhaust manifold and a three-way catalytic converter, and a post-oxygen sensor located between the three-way catalytic converter and an exhaust gas pipeline; acquiring the current monitoring cycle at the current moment; acquiring the two monitoring cycles preceding the current monitoring cycle as two historical monitoring cycles; acquiring the pre-oxygen ion concentration voltage sequence within the two historical monitoring cycles based on the pre-oxygen sensor; acquiring the post-oxygen ion concentration voltage sequence within the two historical monitoring cycles based on the post-oxygen sensor; acquiring a pre-oxygen stability index based on the two pre-oxygen ion concentration voltage sequences; and determining whether the pre-oxygen stability index is... If the oxygen concentration is below the first preset threshold, then the oxygen steady-state range is obtained based on the pre-oxygen stability index, and the oxygen stability index is obtained based on the proportion of the two oxygen ion concentration voltage sequences that are within the oxygen steady-state range. If the oxygen stability index is above the second preset threshold, then the current pre-oxygen ion concentration voltage value and the current oxygen ion concentration voltage value are collected based on the pre-oxygen sensor and the current oxygen ion concentration voltage value, and the current air-fuel ratio is obtained based on the current pre-oxygen ion concentration voltage value and the current oxygen ion concentration voltage value. The standard air-fuel ratio is obtained, and the injector control compensation ratio is obtained based on the current air-fuel ratio and the standard air-fuel ratio.

[0006] Optionally, obtaining the post-oxygen steady-state interval based on the pre-oxygen stability index includes: obtaining an adjustment ratio based on the pre-oxygen stability index and a first preset threshold; obtaining a standard steady-state interval; narrowing the standard steady-state interval based on the adjustment ratio to form the post-oxygen steady-state interval.

[0007] Optionally, obtaining the current air-fuel ratio based on the current upstream oxygen ion concentration voltage value and the current downstream oxygen ion concentration voltage value includes: obtaining the mapping relationship between the upstream oxygen ion concentration voltage and the air-fuel ratio; obtaining the initial air-fuel ratio based on the current upstream oxygen ion concentration voltage value and the mapping relationship; obtaining a correction value based on the current downstream oxygen ion concentration voltage value and the standard steady-state range, and obtaining the current air-fuel ratio based on the correction value and the initial air-fuel ratio.

[0008] Optionally, obtaining the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio includes: determining an adjustment coefficient based on the deviation between the current air-fuel ratio and the standard air-fuel ratio, wherein the adjustment coefficient is used to proportionally scale the base injection pulse width; when the current air-fuel ratio is greater than the standard air-fuel ratio, a positive adjustment coefficient is generated to increase the injection quantity; when the current air-fuel ratio is less than the standard air-fuel ratio, a negative adjustment coefficient is generated to reduce the injection quantity.

[0009] Optionally, the pre-oxygen stability index can be obtained from two pre-oxygen ion concentration-voltage sequences and expressed as follows: , ;in, It serves as an indicator of pre-oxygen stability. As the first weighting coefficient, This is the second weighting coefficient. The number of data collection nodes for the monitoring period. This represents the preceding oxygen ion concentration voltage value corresponding to the (i+1)th data acquisition node in the previous historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the previous historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the (i+1)th data acquisition node in the next historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the next historical monitoring cycle.

[0010] Optionally, the post-oxygen stability index can be obtained based on the proportion of the two post-oxygen ion concentration-voltage sequences that fall within the post-oxygen steady-state range, and is expressed as follows: ; ; ;in, As an indicator of post-oxygen stability, The number of data collection nodes for the monitoring period. For the i-th first intermediate coefficient, This represents the post-oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the previous historical monitoring cycle. This is the minimum value in the post-oxygen steady-state range. This represents the maximum value in the post-oxygen steady-state range. For the i-th second intermediate coefficient, This represents the post-oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the next historical monitoring cycle.

[0011] An air-fuel ratio control system is also provided, comprising: an acquisition module for acquiring a pre-oxygen sensor located between the exhaust manifold and the three-way catalytic converter, and a post-oxygen sensor located between the three-way catalytic converter and the exhaust gas pipeline; acquiring the current monitoring cycle at the current moment; acquiring the two monitoring cycles preceding the current monitoring cycle as two historical monitoring cycles; acquiring the pre-oxygen ion concentration voltage sequence within the two historical monitoring cycles based on the pre-oxygen sensor; and acquiring the post-oxygen ion concentration voltage sequence within the two historical monitoring cycles based on the post-oxygen sensor; and a first data processing module for acquiring a pre-oxygen stability index based on the two pre-oxygen ion concentration voltage sequences and determining the pre-oxygen stability. The system determines whether the indicator is lower than a first preset threshold. If it is, it obtains the steady-state range of the subsequent oxygen based on the preceding oxygen stability indicator and obtains the subsequent oxygen stability indicator based on the proportion of the two subsequent oxygen ion concentration voltage sequences within the steady-state range of the subsequent oxygen. The second data processing module determines whether the subsequent oxygen stability indicator is lower than a second preset threshold. If it is, it collects the current preceding oxygen ion concentration voltage value and the current subsequent oxygen ion concentration voltage value based on the preceding oxygen sensor and the subsequent oxygen sensor, and obtains the current air-fuel ratio based on the current preceding oxygen ion concentration voltage value and the current subsequent oxygen ion concentration voltage value. The control module obtains the standard air-fuel ratio and obtains the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio.

[0012] Optionally, the first data processing module is further configured to: obtain an adjustment ratio based on the pre-oxygen stability index and a first preset threshold; obtain a standard steady-state range; and reduce the standard steady-state range based on the adjustment ratio to form a post-oxygen steady-state range.

[0013] An electronic device is also provided, comprising: a memory storing a computer program thereon; and a processor for executing the computer program in the memory to implement the above-described air-fuel ratio control method.

[0014] A non-transitory computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the above-described air-fuel ratio control method.

[0015] The beneficial effects of this invention are reflected in: In the entire air-fuel ratio control method, firstly, a dual-cycle historical data verification mechanism is adopted. By analyzing the dynamic change characteristics of the voltage sequence of the front oxygen sensor over two consecutive monitoring cycles, the stability under dynamic operating conditions is quantified, replacing the direct dependence on a single sampling value. This fundamentally avoids the risk of misjudgment caused by exhaust disturbance noise and instantaneous electromagnetic interference resulting from rapid acceleration and deceleration. Furthermore, an adaptive strategy for the rear oxygen steady-state range triggered by front oxygen stability is introduced. This strategy utilizes the high response characteristics of the front oxygen sensor to capture the stable state and dynamically compresses the preset standard voltage range boundary based on historical stability. This solves the problem of misjudgment within a fixed range caused by engine conditions and other issues, ensuring that the rear oxygen benchmark judgment matches the actual operating state in real time. Finally, based on dynamic fusion control with dual stability verification, only… When the historical pre-oxygen signal has low volatility and the post-oxygen signal has high convergence within the new range, the instantaneous sensor value at the current moment is allowed to be fused. This involves using the initial air-fuel ratio estimate mapped from the pre-oxygen voltage and superimposing a closed-loop compensation algorithm for the post-oxygen voltage's out-of-boundary amplitude. This retains the rapid response advantage of the pre-oxygen signal while suppressing short-term fluctuations through the post-oxygen filtering characteristics, resulting in an air-fuel ratio that more closely resembles the actual combustion state. Finally, a nonlinear injection compensation mechanism is used to achieve precise execution. Based on the direction and magnitude of the deviation between the corrected post-oxygen air-fuel ratio and the theoretical value, a scaling ratio is dynamically generated to perform bidirectional adjustment (increasing fuel when too lean, decreasing fuel when too rich). This avoids the injection pulse width oscillation caused by signal distortion in traditional methods, and simultaneously optimizes combustion efficiency and emission levels under complex operating conditions such as sudden load changes, cold starts, and high-altitude low-pressure conditions. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a partial flowchart of the air-fuel ratio control method of the present invention; Figure 2 This is a schematic diagram of another part of the air-fuel ratio control method of the present invention; Figure 3 This is a schematic diagram of the steps of the air-fuel ratio control method of the present invention; Figure 4 This is a schematic diagram of a portion of steps S2 in the air-fuel ratio control method of the present invention; Figure 5 This is a schematic diagram of a portion of step S3 in the air-fuel ratio control method of the present invention; Figure 6 This is a schematic diagram of a portion of step S4 in the air-fuel ratio control method of the present invention; Figure 7This is a block diagram illustrating an electronic device according to an embodiment of the present invention.

[0018] Figure label: 700 - Electronic device; 701 - Processor; 702 - Memory; 703 - Multimedia component; 704 - I / O interface; 705 - Communication component. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] like Figure 1 , Figure 2 and Figure 3 As shown, an air-fuel ratio control method is provided, including: S1. Obtain the front oxygen sensor located between the exhaust manifold and the three-way catalytic converter and the rear oxygen sensor located between the three-way catalytic converter and the exhaust gas pipeline. Obtain the current monitoring cycle at the current moment. Obtain the two monitoring cycles before the current monitoring cycle and use them as two historical monitoring cycles. Obtain the front oxygen ion concentration voltage sequence in the two historical monitoring cycles according to the front oxygen sensor. Obtain the rear oxygen ion concentration voltage sequence in the two historical monitoring cycles according to the rear oxygen sensor. S2. Obtain the pre-oxygen stability index based on the two pre-oxygen ion concentration voltage sequences, and determine whether the pre-oxygen stability index is lower than the first preset threshold. If it is lower, obtain the post-oxygen steady-state interval based on the pre-oxygen stability index, and obtain the post-oxygen stability index based on the proportion of the two post-oxygen ion concentration voltage sequences that are in the post-oxygen steady-state interval. S3. Determine whether the post-oxygen stability index is higher than the first preset threshold. If it is higher, collect the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value at the current moment based on the pre-oxygen sensor and the post-oxygen sensor, and obtain the current air-fuel ratio based on the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value. S4. Obtain the standard air-fuel ratio and obtain the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio.

[0023] In this embodiment, it should be noted that in S1, as the initial data acquisition stage, the core objective is to establish a historical benchmark for sensor data. Specifically, firstly, the ion concentration voltage signal in the exhaust gas is acquired in real time through a front oxygen sensor physically installed between the exhaust manifold and the three-way catalytic converter, and a rear oxygen sensor located between the three-way catalytic converter and the exhaust gas pipeline. Simultaneously, the operating time is divided into fixed monitoring cycles (e.g., data acquisition windows defined based on engine speed or time intervals), and based on the current monitoring cycle, the previous two consecutive cycles are traced and extracted as historical references. Within each monitoring cycle, the data acquired from the front oxygen sensor is organized into a front oxygen ion concentration voltage sequence, representing the dynamic change trajectory of the sensor voltage value within the corresponding time period; similarly, the data acquired from the rear oxygen sensor forms a rear oxygen ion concentration voltage sequence, and the two together constitute the key input source. This step solves the problem of distortion caused by single sampling in existing methods because it emphasizes multi-cycle sequences rather than instantaneous points, and can eliminate transient interferences such as exhaust pulsation in advance, providing a continuous data background for subsequent stability assessment.

[0024] Furthermore, when the engine enters a new monitoring window (e.g., a 100ms cycle), the control immediately retrieves the stored records from the previous two historical cycles: assuming the preceding cycle's pre-oxygen voltage sequence contains an ordered change in voltage values ​​from initial to final, while the following cycle's post-oxygen sequence records a smooth response trend under deceleration conditions. Similarly, the pre-oxygen sequence exhibits a continuous chain of rising or falling values ​​in historical data, while the post-oxygen sequence reflects a lagging but stable trend line; both are stored sequentially by time point. These sequences allow analysis of common patterns in sensor activity during dynamic events (e.g., noise characteristics during historical acceleration or deceleration), laying the foundation for calculating the stability index in step S2 and avoiding misjudgments caused by directly relying on current distorted sampling.

[0025] In S2, the stability of the pre-oxygen sensor is quantified using historical data, and the baseline judgment range of the post-oxygen sensor is dynamically corrected accordingly. First, volatility analysis is performed on the pre-oxygen voltage sequence for two historical monitoring cycles. Stability is assessed by calculating the cumulative value of the change in continuous voltage values ​​within the sequence (e.g., the smoothness of the voltage curve within the monitoring cycle). If this stability index is higher than a specific threshold (i.e., low volatility), it indicates that the exhaust gas flow was stable and there were no drastic changes in operating conditions during the historical period, at which point it is determined that the current moment meets the conditions for executing subsequent operations. Subsequently, an adjustment ratio is generated based on the deviation of the pre-oxygen stability index from the threshold—the more stable the historical data (the higher the index), the larger the adjustment ratio, thereby further contracting and compressing the preset post-oxygen standard steady-state range (e.g., proportionally tightening the boundary of the contraction range), forming an adaptively narrowed new post-oxygen steady-state range. This step essentially utilizes the high responsiveness of the pre-oxygen signal to capture stability, avoiding misjudgments caused by a fixed range.

[0026] Furthermore, it is necessary to verify whether the post-oxygen signal conforms to the expected new steady-state range within the historical period. Specifically, all data points from two historical post-oxygen voltage sequences are iterated, and the proportion falling within the adaptive range is calculated. If most data points are within the range (e.g., a smooth voltage cluster under the action of the three-way catalytic converter after rapid deceleration), it indicates that the post-oxygen signal has reached a stable level due to catalytic converter filtering. If a large number of data points deviate from the range (e.g., abnormal fluctuations when the catalytic converter fails to ignite during cold start), it suggests a risk of distortion in the post-oxygen signal itself. This proportion is converted into a post-oxygen stability index, serving as the basis for subsequent air-fuel ratio correction using the current real-time signal. For example, when the vehicle smoothly transitions from high-speed cruising, the range contraction triggered by minimal fluctuations in the previous historical oxygen sequence, combined with the high proportion of the post-oxygen sequence falling almost entirely within the new range, ensures the reliability of control in the next stage.

[0027] In S3, after dual stability verification, the instantaneous sensor values ​​at the current moment are fused and calculated to dynamically correct the initial air-fuel ratio estimate. When the historical data of the preceding oxygen is determined to be stable (the preceding oxygen stability index in S2 is lower than the first preset threshold) and the proportion of the historical data of the following oxygen within the adaptive range meets the standard (the following oxygen stability index is higher than the second preset threshold), it indicates that the current operating condition is in a reliable stable state. At this time, the real-time voltage value of the preceding oxygen sensor is simultaneously acquired—utilizing its fast response characteristics to capture the instantaneous exhaust state, and converting it into the initial air-fuel ratio estimate through a preset voltage-air-fuel ratio mapping table. At the same time, the voltage value of the following oxygen sensor is read. Although it lags, it is filtered by the three-way catalytic converter and better reflects the overall trend of the mixture. The key to this step is that instantaneous signals susceptible to noise are only allowed to be used when historical data proves that there is no sudden interference, avoiding distorted sampling from directly triggering control.

[0028] Furthermore, a post-oxygen signal is introduced to dynamically correct the initial estimate to improve accuracy. Specifically, the current post-oxygen voltage value is compared to the adaptive steady-state range. If the voltage exceeds the upper limit of the range, the actual air-fuel ratio is determined to be richer than the instantaneous pre-oxygen value (e.g., the oxygen voltage remains high after rapid acceleration due to catalytic converter lag), and the initial air-fuel ratio needs to be leaned according to preset rules; conversely, if it is below the lower limit, it is enriched. The correction strength is determined by the extent of the deviation: slight deviations trigger small-range corrections, while severe deviations result in strong compensation. For example, when the vehicle smoothly transitions from idle to constant speed, the instantaneous pre-oxygen value indicates a normal air-fuel ratio, but the post-oxygen voltage, due to lag, is still slightly higher than the upper limit of the new range. Based on this, the initial estimate is finely adjusted to compensate for minor deviations that the pre-oxygen signal might ignore, ultimately outputting an air-fuel ratio closer to the actual combustion state.

[0029] In S4, the corrected air-fuel ratio estimate is converted into a precise fuel injection quantity compensation command, realizing the execution layer adjustment in closed-loop control. Specifically, it first compares the direction and magnitude of the deviation between the current air-fuel ratio and the theoretical standard air-fuel ratio (e.g., current value 14.76 vs. standard value 14.70), and dynamically generates an adjustment coefficient based on the degree of deviation. This coefficient is not a fixed ratio, but rather maps different reduction ratios according to different data ranges: a small ratio compensation is used for slight deviations to avoid over-adjustment; strong compensation is activated for significant deviations to accelerate convergence. This step scales the base injection pulse width by quantifying the deviation, rather than directly replacing the original control, ensuring a smooth transition to near the theoretical air-fuel ratio during the adjustment process.

[0030] Furthermore, the fuel injection quantity needs to be adjusted bidirectionally according to the required air-fuel mixture concentration. When the current air-fuel ratio is greater than the standard value (the mixture is too lean), a positive adjustment coefficient is generated to proportionally increase the fuel injection pulse width to supplement fuel supply; conversely, when the current air-fuel ratio is less than the standard value (the mixture is too rich), a negative adjustment coefficient is generated to reduce the fuel injection pulse width. For example, when the vehicle encounters an uphill load while cruising, the air-fuel ratio output by S3 will be higher than the standard value due to the increased intake air volume. The fuel injection quantity will be automatically increased to a reasonable range, which avoids both sluggish acceleration and emissions deterioration, ultimately achieving synergistic optimization of combustion stability and emissions control.

[0031] In summary, the entire air-fuel ratio control method firstly employs a dual-cycle historical data verification mechanism. By analyzing the dynamic change characteristics of the voltage sequence of the pre-oxygen sensor over two consecutive monitoring cycles, it quantifies the stability under dynamic operating conditions, replacing the direct reliance on single sampling values. This fundamentally avoids the risk of misjudgment caused by exhaust disturbance noise and instantaneous electromagnetic interference resulting from rapid acceleration and deceleration. Furthermore, it introduces an adaptive strategy for the post-oxygen steady-state range triggered by pre-oxygen stability. This strategy utilizes the high-response characteristics of the pre-oxygen sensor to capture the stable state and dynamically compresses the preset standard voltage range boundary based on historical stability. This solves the problem of misjudgment within a fixed range caused by engine conditions and other issues, ensuring real-time matching between the post-oxygen benchmark judgment and the actual operating state. Finally, it employs dynamic fusion control based on dual stability verification. The system allows the fusion of the current sensor instantaneous value only when the historical pre-oxygen signal has low volatility and the post-oxygen signal has high convergence within the new range. This involves using the initial air-fuel ratio estimate mapped from the pre-oxygen voltage and superimposing a closed-loop compensation algorithm for the post-oxygen voltage's out-of-boundary amplitude. This retains the rapid response advantage of the pre-oxygen signal while suppressing short-term fluctuations through the post-oxygen filtering characteristics, resulting in an air-fuel ratio that more closely resembles the actual combustion state. Finally, a nonlinear injection compensation mechanism enables precise execution. Based on the direction and magnitude of the deviation between the corrected post-oxygen air-fuel ratio and the theoretical value, a scaling ratio is dynamically generated to perform bidirectional adjustment (increasing fuel when too lean, decreasing fuel when too rich). This avoids the injection pulse width oscillations caused by signal distortion in traditional methods, and simultaneously optimizes combustion efficiency and emission levels under complex operating conditions such as sudden load changes, cold starts, and high-altitude low-pressure conditions.

[0032] like Figure 1 and Figure 4 As shown, in one embodiment, obtaining the post-oxygen steady-state range based on the pre-oxygen stability index in S2 includes: S21. Obtain the adjustment ratio based on the pre-oxygen stability index and the first preset threshold; S22. Obtain the standard steady-state range, reduce the standard steady-state range according to the adjustment ratio, and form the post-oxygen steady-state range.

[0033] In this embodiment, it should be noted that the core of S21 lies in converting the quantification result of the pre-oxygen stability index into an intensity parameter for range adjustment. Specifically, the adjustment ratio is dynamically determined based on the difference between the pre-oxygen stability index and a first preset threshold: the lower the volatility of the current oxygen historical sequence (i.e., the closer the index is to the highest stable level), the larger the absolute value of this difference, and the larger the corresponding adjustment ratio. This design reflects a key logic—when historical data proves that the exhaust state is highly stable, the post-oxygen benchmark range can be more aggressively narrowed to improve judgment sensitivity. For example, if the engine returns to stable cruising after rapid acceleration, and the pre-oxygen sequence continues to show small fluctuations (significant difference), an adjustment ratio close to the upper limit is generated, providing strong impetus for subsequent range compression.

[0034] Furthermore, the adjustment ratio is calculated based on the difference between the pre-oxygen stability index and the first preset threshold. The specific formula is: Adjustment ratio K = min((first preset threshold - pre-oxygen stability index) / first preset threshold, maximum adjustment ratio upper limit). The maximum adjustment ratio upper limit is typically set to 0.8 to prevent excessive narrowing of the adjustment range.

[0035] For example, setting the first preset threshold to 0.7 (representing a stable baseline): Case 1, if the pre-oxygen stability index is 0.6 (below the threshold of 0.7), the absolute value of the difference is 0.1, and the adjustment ratio K=min(0.1 / 0.7, 0.8)≈min(0.1429, 0.8)=0.1429, which indicates good stability and a small adjustment ratio; Case 2: if the pre-oxygen stability index is 0.2 (far below the threshold of 0.7), the absolute value of the difference is 0.5, and the adjustment ratio K=min(0.5 / 0.7, 0.8)≈min(0.7143, 0.8)=0.7143, which indicates excellent stability, a larger adjustment ratio, and drives more significant interval compression.

[0036] In S22, the generation of the post-oxygen steady-state range involves directional contraction of the standard steady-state range using an adjustment ratio to form a dynamic reference range adapted to actual operating conditions. First, a preset standard steady-state range (such as a broad voltage band calibrated on a test bench) is invoked. Then, the boundaries of this range are narrowed according to the adjustment ratio: the larger the ratio, the greater the inward contraction of the upper and lower limits of the range, but an upper limit for contraction is set to prevent excessive narrowing that could lead to a loss of fault tolerance. For example, in a high-altitude, low-pressure environment where the engine operates stably for a long time, after the pre-oxygen stability index is extremely high, triggering a significant contraction, the new post-oxygen steady-state range retains only the core portion of the standard range (e.g., excluding edge fluctuations). If the post-oxygen voltage is relatively high compared to the overall calibration value, this contraction mechanism can automatically match the voltage offset, avoiding misinterpreting a normal rich mixture signal as abnormal.

[0037] Furthermore, the standard steady-state interval is symmetrically reduced based on the adjustment ratio, and the formula is: Post-oxygen steady-state interval = [original minimum value + (adjustment ratio × interval half width), original maximum value - (adjustment ratio × interval half width)], where the interval half width = (original maximum value - original minimum value) / 2.

[0038] For example, setting the standard steady-state range as [650mV, 750mV] (half-width 50mV): Case 1, adjustment ratio K = 0.1429, new minimum value = 650 + (0.1429 × 50) ≈ 650 + 7.145 = 657.145mV, new maximum value = 750 - (0.1429 × 50) ≈ 750 - 7.145 = 742.855mV, new range [657mV, 743mV]. Case 2: Adjustment ratio K=0.7143, new minimum value=650+(0.7143×50)≈650+35.715=685.715mV, new maximum value=750-(0.7143×50)≈750-35.715=714.285mV, new interval [686mV, 714mV], which reflects the significant contraction of the interval under high stability and improves the judgment sensitivity.

[0039] like Figure 5 As shown, in one embodiment, obtaining the current air-fuel ratio in S3 based on the current preceding oxygen ion concentration voltage value and the current following oxygen ion concentration voltage value includes: S31. Obtain the mapping relationship between pre-oxygen ion concentration voltage and air-fuel ratio; S32. Obtain the initial air-fuel ratio based on the current oxygen ion concentration voltage value and mapping relationship; S33. Obtain the correction value based on the current post-oxygen ion concentration voltage value and the standard steady-state range, and obtain the current air-fuel ratio based on the correction value and the initial air-fuel ratio.

[0040] In this embodiment, it should be noted that in S31, a physical correlation is established between the pre-oxygen voltage signal and the air-fuel ratio. The mapping relationship between the pre-oxygen ion concentration voltage and the air-fuel ratio is established through a physical quantity conversion database based on engine bench calibration experiments. This database is not based on mathematical models or algorithms, but rather on standardized experimental procedures and physical measurement data. The specific steps are as follows: Maintain the engine at a fixed operating point (e.g., 2000 rpm, 50% load), and adjust the fuel injection quantity in a stepwise manner through the fuel supply system to continuously transition the exhaust air-fuel ratio from a lean mixture (air-fuel ratio > 1) to a rich mixture (air-fuel ratio < 1), covering the entire operating range of the sensor. Then, after each adjustment of the fuel injection quantity and waiting for the system to stabilize, measure the actual air-fuel ratio using an air-fuel ratio analyzer, and simultaneously read the output voltage of the pre-oxygen sensor. Repeat the above operation to obtain multiple sets of corresponding data points. Finally, arrange the valid data pairs in ascending order of voltage value, generate a discrete mapping table, and store it. For example, typical data is as follows:

[0041] Furthermore, firstly, the stored voltage-air-fuel ratio discrete mapping table is invoked. This table, generated based on engine bench calibration experiments, accurately records the correspondence between the voltage value output by the front oxygen sensor and the theoretical air-fuel ratio under different exhaust oxygen concentrations. This mapping is essentially a non-linear curve: the low voltage region corresponds to a lean mixture (high air-fuel ratio), and the high voltage region corresponds to a rich mixture (low air-fuel ratio). For example, when the oxygen content in the exhaust suddenly increases (such as when the throttle opening increases), the front oxygen voltage will quickly drop to a low value range. At this time, the mapping table can immediately convert the voltage change into the air-fuel ratio offset.

[0042] In S32, the instantaneous state is captured by utilizing the rapid response characteristics of the pre-oxygen voltage in real time. The pre-oxygen voltage value collected at the current moment is input into a mapping table, and an initial air-fuel ratio estimate is output through interpolation. For example, when the exhaust gas flow returns to a stable state after rapid deceleration, the pre-oxygen voltage drops from its peak to a moderate level, and the mapping table outputs a moderate air-fuel ratio value. This step fully leverages the advantage of the pre-oxygen response speed, providing a baseline reference for subsequent corrections, but its susceptibility to transient noise interference should be noted.

[0043] For example, based on the real-time pre-oxygen voltage lookup table, the initial estimate is output: the exhaust is stable, and the current pre-oxygen ion concentration voltage value drops to 600mV; the lookup result is 600mV → air-fuel ratio 14.3 (directly matching the calibration point).

[0044] In the case of interpolation: if the voltage is 650mV (between 600-750mV), calculated by linear interpolation: air-fuel ratio difference = 14.3-13.8 = 0.5; voltage difference = 750-600 = 150mV; change in air-fuel ratio per unit voltage = 0.5 / 150 ≈ 0.0033 / mV; 650mV offset = (650-600) × 0.0033 ≈ 0.165; initial air-fuel ratio = 14.3-0.165 = 14.135.

[0045] In S33, a delayed but stable post-oxygen voltage signal is introduced to compensate for the initial estimate. This involves three steps. First, boundary comparison: the current post-oxygen voltage value is compared with the adaptive steady-state range generated by S2. Second, correction direction determination: if the post-oxygen voltage exceeds the upper limit of the range (indicating excessively rich exhaust gas after the catalytic converter), the initial air-fuel ratio needs to be leaned downwards; if it is below the lower limit (indicating excessively lean), it needs to be enriched upwards. Finally, correction intensity calculation: based on the absolute magnitude of exceeding the boundary, the compensation amount is increased in stages according to preset rules—the greater the exceedance, the larger the correction coefficient, and the correction intensity has a non-linear increasing relationship with the boundary offset. For example, in a high-altitude, low-pressure environment, the pre-oxygen voltage indicates a normal air-fuel ratio (the initial estimate is reasonable), but the post-oxygen voltage continuously outputs a higher voltage due to low atmospheric oxygen content. When its value exceeds the upper limit of the adaptive range, the initial estimate is significantly leaned according to the exceedance ratio to compensate for the continuous rich mixture trend not perceived by the pre-oxygen voltage, ultimately outputting an air-fuel ratio that matches the actual operating conditions.

[0046] Further, for example, firstly, the boundary comparison and correction direction are performed. The post-oxygen adaptive steady-state range (generated by S22) is [650mV, 750mV]. The current post-oxygen voltage is 780mV, which exceeds the upper limit by 30mV (780-750=30). The judgment is: exceeding the upper limit indicates the mixture is too rich and needs to be leaned (the initial air-fuel ratio is corrected downwards). Then, the correction intensity is calculated. It is set that for every 10mV exceeding the limit, the correction amount (air-fuel ratio) changes by 0.03. Therefore, the total exceeding limit = 30mV, and the correction amount = (30 / 10)×(0.03) = 0.09. Finally, the initial air-fuel ratio (S32 output) is 14.85, the correction amount is 0.09, and the current air-fuel ratio = 14.85-0.09 = 14.76 (based on the above judgment result, the initial air-fuel ratio is corrected downwards).

[0047] In summary, the entire correction mechanism utilizes a dual-sensor complementary approach: the initial oxygen sensor provides a transient reference by avoiding the rapid but distorted response of the latter, while the latter oxygen sensor, though lagging, is filtered by the catalytic converter, thus correcting system deviations. The final output value simultaneously overcomes noise from sudden changes in operating conditions and high environmental interference, reducing the air-fuel ratio control error from ±0.5 in traditional methods to within ±0.1.

[0048] like Figure 6 As shown, in one embodiment, obtaining the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio in step S4 includes: S41. Determine the adjustment coefficient based on the degree of deviation between the current air-fuel ratio and the standard air-fuel ratio, wherein the adjustment coefficient is used to scale the base injection pulse width proportionally. S42. When the current air-fuel ratio is greater than the standard air-fuel ratio, a positive adjustment coefficient is generated to increase the fuel injection quantity. S43. When the current air-fuel ratio is less than the standard air-fuel ratio, a negative adjustment coefficient is generated to reduce the amount of fuel injected.

[0049] In this embodiment, it should be noted that in S41, the compensation intensity is dynamically scaled according to the air-fuel ratio deviation. First, the absolute deviation of the current air-fuel ratio from the standard value is calculated (e.g., |14.76-14.70|=0.06). Based on a preset nonlinear response curve, the adjustment coefficient is determined: when the deviation is less than the critical value (e.g., 0.05), a low gain coefficient is used to avoid over-adjustment; when the deviation exceeds the critical value, a high gain coefficient is activated to accelerate convergence. This design is essentially a fuzzy control rule—conservative adjustment to maintain stability when the deviation is small, and aggressive compensation for rapid correction when the deviation is large. For example, during cold start, if the mixture is momentarily too rich (deviation 0.1), a high gain coefficient (e.g., 0.8) is activated, while steady-state micro-fluctuations (deviation 0.02) only trigger a micro-gain (e.g., 0.1).

[0050] In S42, a fuel add-on strategy is implemented for lean air-fuel mixtures. When the current air-fuel ratio is greater than the standard value (e.g., 15.2 > 14.70), a positive adjustment coefficient (positive value) is generated, proportionally expanding the base injection pulse width: New pulse width = Base pulse width × (1 + Adjustment coefficient). For example, during cruising, a sudden acceleration causes a surge in intake air, and the current air-fuel ratio jumps to 15.1. The injection pulse width is expanded to 160% of the base value with an adjustment coefficient of 0.6 to quickly fill the fuel gap and prevent combustion interruption. This process simultaneously monitors exhaust temperature to avoid excessive add-on fuel that could lead to excessive exhaust temperature.

[0051] S43 is a fuel reduction mechanism for rich air-fuel mixtures. When the current air-fuel ratio is less than the standard value (e.g., 13.8 < 14.70), a negative adjustment coefficient (negative value) is generated, compressing the injection pulse width: New pulse width = Base pulse width × (1 - |adjustment coefficient|). For example, if the mixture is too rich (air-fuel ratio 13.9) when fuel supply is restored after deceleration cutoff, the pulse width is reduced to 50% of the base value with an adjustment coefficient of 0.5. Key protection design: When the adjusted pulse width approaches the minimum injection critical point, the reduction amount is frozen to maintain the minimum fuel supply, preventing injector stall.

[0052] In one implementation, the pre-oxygen stability index obtained in S2 based on two pre-oxygen ion concentration-voltage sequences is expressed as follows: , ;in, It serves as an indicator of pre-oxygen stability. As the first weighting coefficient, This is the second weighting coefficient. The number of data collection nodes for the monitoring period. This represents the preceding oxygen ion concentration voltage value corresponding to the (i+1)th data acquisition node in the previous historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the previous historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the (i+1)th data acquisition node in the next historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the next historical monitoring cycle.

[0053] In this embodiment, it should be noted that, and Both methods directly calculate the voltage difference between adjacent nodes, rather than the absolute value, allowing results to be positive (rising trend) or negative (falling trend). This results in higher stability during rapid acceleration and deceleration. During rapid acceleration, the exhaust oxygen concentration drops sharply, and the voltage increases continuously in one direction (the difference sequence is all positive), resulting in a large positive sum. The absolute value is then used to eliminate the sign, leading to higher stability. During rapid deceleration, the oxygen concentration increases sharply, and the voltage decreases continuously in one direction (the difference sequence is all negative), resulting in a large negative sum. The absolute value is then used to eliminate the sign, also leading to higher stability. Under normal stable operating conditions, the voltage fluctuates slightly in both directions around the mean (e.g., +10mV followed by 8mV), with the positive and negative differences partially canceling each other out. The sum approaches zero (low fluctuation), and the absolute value is used to eliminate the sign, resulting in lower stability. If absolute values ​​are used, both unidirectional sudden changes and bidirectional noise will output high positive values, making it impossible to distinguish between real-world sudden changes and transient interference. This design uses direction sensitivity to separate unidirectional drift (sudden changes in operating conditions) from oscillation noise.

[0054] Furthermore, a dual-cycle weighted fusion mechanism is implemented; weights are assigned to the difference between the two historical monitoring cycles. and ,and Then sum them up. If the previous period is in a state of rapid acceleration and the subsequent period enters a stable state, let... , This can increase the weight of later cycles, thereby weakening the contribution of unstable earlier cycles and increasing the contribution of stable later cycles. In other words, recent later cycles usually reflect the current state better, and are generally set... > (like This allows the system to focus more on the latest trends and avoid early fluctuations.

[0055] In one implementation, the post-oxygen stability index obtained in S2 based on the proportion of the two post-oxygen ion concentration-voltage sequences that are within the post-oxygen steady-state range is expressed as follows: ; ; ;in, As an indicator of post-oxygen stability, The number of data collection nodes for the monitoring period. For the i-th first intermediate coefficient, This represents the post-oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the previous historical monitoring cycle. This is the minimum value in the post-oxygen steady-state range. This represents the maximum value in the post-oxygen steady-state range. For the i-th second intermediate coefficient, This represents the post-oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the next historical monitoring cycle.

[0056] In one implementation method, it should be noted that, and All of these reflect a 0 / 1 binary quantization mechanism (core anti-interference design); each data point is assigned a value of 1 if it falls within the specified interval, and 0 if it falls outside the interval. Therefore, occasional spikes caused by electromagnetic interference and exhaust pulsations (such as a single-point voltage surge to 800mV during cold start) and actual over-limit voltage values ​​are directly assigned as 0 and do not participate in the percentage calculation. Furthermore, when the catalytic converter is at low temperature, the post-oxygen voltage continuously oscillates at a low frequency (e.g., [650, 690, 620, 710]mV). Assuming the new interval is [680, 720], then 690mV is assigned 1, 620mV is assigned 0, and 710mV is assigned 1; the effective data percentage is 50%, accurately reflecting the "unstable state" rather than misjudging it as a fault.

[0057] Furthermore, it also embodies the global integration of the dual-cycle. Count the number of valid points in the previous period. Count the valid points for the next period, sum them, and divide by the total number of points, 2n. If 40% of the data in the previous period was out of range due to deceleration disturbance (…), then… After the cycle, the recovery rate stabilizes within 90% of the range. ),but: It neither excessively punishes early-cycle disturbances nor ignores late-cycle improvements.

[0058] Furthermore, it also reflects output normalization and threshold decision-making. This means that all data points in both periods are within the adaptive range (highly stable). This indicates that all data deviates from the range (severe instability). Let the second preset threshold be 0.9. If the oxygen signal ratio is deemed to meet the standard, the current real-time signal will be used to correct the air-fuel ratio. This skips the control to prevent catalytic converter filter failure from causing correction distortion.

[0059] An air-fuel ratio control system is also provided, the system including: The acquisition module is used to acquire the front oxygen sensor located between the exhaust manifold and the three-way catalytic converter and the rear oxygen sensor located between the three-way catalytic converter and the exhaust gas pipeline, acquire the current monitoring cycle at the current moment, acquire the two monitoring cycles before the current monitoring cycle as two historical monitoring cycles, and acquire the front oxygen ion concentration voltage sequence in the two historical monitoring cycles according to the front oxygen sensor, and acquire the rear oxygen ion concentration voltage sequence in the two historical monitoring cycles according to the rear oxygen sensor. The first data processing module is used to obtain the pre-oxygen stability index based on two pre-oxygen ion concentration voltage sequences, and determine whether the pre-oxygen stability index is lower than a first preset threshold. If it is lower, the module obtains the post-oxygen steady-state interval based on the pre-oxygen stability index, and obtains the post-oxygen stability index based on the proportion of the two post-oxygen ion concentration voltage sequences that are within the post-oxygen steady-state interval. The second data processing module is used to determine whether the post-oxygen stability index is lower than the second preset threshold. If it is lower, it collects the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value at the current moment based on the pre-oxygen sensor and the post-oxygen sensor, and obtains the current air-fuel ratio based on the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value. The control module is used to obtain the standard air-fuel ratio and to obtain the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio.

[0060] In one embodiment, the first data processing module is further configured to: obtain an adjustment ratio based on the pre-oxygen stability index and a first preset threshold; obtain a standard steady-state range; and reduce the standard steady-state range based on the adjustment ratio to form a post-oxygen steady-state range.

[0061] In this embodiment, it should be noted that the specific method of performing the above-mentioned air-fuel ratio control system has been described in detail in the embodiments of the air-fuel ratio control method, and will not be elaborated here.

[0062] Figure 7 This is a block diagram of an electronic device illustrating an air-fuel ratio control method according to an exemplary embodiment. Figure 7 As shown, the electronic device 700 may include: a processor 701 and a memory 702. The electronic device 700 may also include one or more of a multimedia component 703, an I / O interface 704 (input / output interface), and a communication component 705.

[0063] The processor 701 controls the overall operation of the electronic device 700 to complete all or part of the steps in the air-fuel ratio control method described above. The memory 702 stores various types of data to support the operation of the electronic device 700. This data may include, for example, instructions for any application or method operating on the electronic device 700, and application-related data such as contact data, sent and received messages, pictures, audio, video, etc. The memory 702 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The multimedia component 703 may include a screen and audio components. The screen may be, for example, a touchscreen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in memory 702 or transmitted via communication component 705. The audio component also includes at least one speaker for outputting audio signals. I / O interface 704 provides an interface between processor 701 and other interface modules, such as a keyboard, mouse, buttons, etc. These buttons may be virtual or physical buttons. Communication component 705 is used for wired or wireless communication between the electronic device 700 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IoT, eMTC, or other 5G technologies, or a combination thereof, is not limited here. Therefore, the corresponding communication component 705 may include: a Wi-Fi module, a Bluetooth module, an NFC module, etc.

[0064] In an exemplary embodiment, the electronic device 700 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the air-fuel ratio control method described above.

[0065] In another exemplary embodiment, a computer-readable storage medium including program instructions is also provided, which, when executed by a processor, implement the steps of the air-fuel ratio control method described above. For example, the computer-readable storage medium may be the memory 702 including program instructions described above, which may be executed by the processor 701 of the electronic device 700 to complete the air-fuel ratio control method described above.

[0066] In another exemplary embodiment, a computer program product is also provided, the computer program product comprising a computer program executable by a programmable device, the computer program having a code portion for performing the above-described air-fuel ratio control method when executed by the programmable device.

[0067] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0068] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0069] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An air-fuel ratio control method, characterized in that, include: The system acquires the front oxygen sensor located between the exhaust manifold and the three-way catalytic converter and the rear oxygen sensor located between the three-way catalytic converter and the exhaust gas pipeline. It acquires the current monitoring cycle at the current moment, acquires the two monitoring cycles before the current monitoring cycle and uses them as two historical monitoring cycles. It also acquires the front oxygen ion concentration voltage sequence in the two historical monitoring cycles based on the front oxygen sensor and the rear oxygen ion concentration voltage sequence in the two historical monitoring cycles based on the rear oxygen sensor. The pre-oxygen stability index is obtained based on two pre-oxygen ion concentration voltage sequences, and it is determined whether the pre-oxygen stability index is lower than a first preset threshold. If it is lower, the post-oxygen steady-state interval is obtained based on the pre-oxygen stability index, and the post-oxygen stability index is obtained based on the proportion of the two post-oxygen ion concentration voltage sequences that are in the post-oxygen steady-state interval. Determine whether the post-oxygen stability index is higher than the second preset threshold. If it is higher, collect the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value at the current moment based on the pre-oxygen sensor and the post-oxygen sensor, and obtain the current air-fuel ratio based on the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value. Obtain the standard air-fuel ratio, and then determine the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio.

2. The air-fuel ratio control method according to claim 1, characterized in that, The method for obtaining the post-oxygen steady-state range based on the pre-oxygen stability index includes: The adjustment ratio is obtained based on the pre-oxygen stability index and the first preset threshold. Obtain the standard steady-state range, and reduce the standard steady-state range according to the adjustment ratio to form the post-oxygen steady-state range.

3. The air-fuel ratio control method according to claim 2, characterized in that, The process of obtaining the current air-fuel ratio based on the current front oxygen ion concentration voltage value and the current rear oxygen ion concentration voltage value includes: Obtain the mapping relationship between pre-oxygen ion concentration voltage and air-fuel ratio; The initial air-fuel ratio is obtained based on the current pre-oxygen ion concentration voltage value and mapping relationship; The correction value is obtained based on the current post-oxygen ion concentration voltage value and the standard steady-state range, and the current air-fuel ratio is obtained based on the correction value and the initial air-fuel ratio.

4. The air-fuel ratio control method according to claim 1, characterized in that, The process of obtaining the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio includes: An adjustment coefficient is determined based on the degree of deviation between the current air-fuel ratio and the standard air-fuel ratio, wherein the adjustment coefficient is used to scale the base injection pulse width proportionally. When the current air-fuel ratio is greater than the standard air-fuel ratio, a positive adjustment coefficient is generated to increase the fuel injection quantity; When the current air-fuel ratio is less than the standard air-fuel ratio, a negative adjustment coefficient is generated to reduce the amount of fuel injected.

5. The air-fuel ratio control method according to claim 1, characterized in that, The pre-oxygen stability index obtained based on two pre-oxygen ion concentration-voltage sequences is expressed as follows: , ;in, It serves as an indicator of pre-oxygen stability. As the first weighting coefficient, This is the second weighting coefficient. The number of data collection nodes for the monitoring period. This represents the preceding oxygen ion concentration voltage value corresponding to the (i+1)th data acquisition node in the previous historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the previous historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the (i+1)th data acquisition node in the next historical monitoring cycle. This represents the preceding oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the next historical monitoring cycle.

6. The air-fuel ratio control method according to claim 1, characterized in that, The post-oxygen stability index, obtained based on the proportion of post-oxygen ion concentration-voltage sequences within the post-oxygen steady-state range, is expressed as follows: ； ； ;in, As an indicator of post-oxygen stability, The number of data collection nodes for the monitoring period. For the i-th first intermediate coefficient, This represents the post-oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the previous historical monitoring cycle. This is the minimum value in the post-oxygen steady-state range. This represents the maximum value in the post-oxygen steady-state range. For the i-th second intermediate coefficient, This represents the post-oxygen ion concentration voltage value corresponding to the i-th data acquisition node in the next historical monitoring cycle.

7. An air-fuel ratio control system, characterized in that, The system includes: The acquisition module is used to acquire the front oxygen sensor located between the exhaust manifold and the three-way catalytic converter and the rear oxygen sensor located between the three-way catalytic converter and the exhaust gas pipeline, acquire the current monitoring cycle at the current moment, acquire the two monitoring cycles before the current monitoring cycle as two historical monitoring cycles, and acquire the front oxygen ion concentration voltage sequence in the two historical monitoring cycles according to the front oxygen sensor, and acquire the rear oxygen ion concentration voltage sequence in the two historical monitoring cycles according to the rear oxygen sensor. The first data processing module is used to obtain the pre-oxygen stability index based on two pre-oxygen ion concentration voltage sequences, and determine whether the pre-oxygen stability index is lower than a first preset threshold. If it is lower, the module obtains the post-oxygen steady-state interval based on the pre-oxygen stability index, and obtains the post-oxygen stability index based on the proportion of the two post-oxygen ion concentration voltage sequences that are within the post-oxygen steady-state interval. The second data processing module is used to determine whether the post-oxygen stability index is lower than the second preset threshold. If it is lower, it collects the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value at the current moment based on the pre-oxygen sensor and the post-oxygen sensor, and obtains the current air-fuel ratio based on the current pre-oxygen ion concentration voltage value and the current post-oxygen ion concentration voltage value. The control module is used to obtain the standard air-fuel ratio and to obtain the injector control compensation ratio based on the current air-fuel ratio and the standard air-fuel ratio.

8. The air-fuel ratio control system according to claim 7, characterized in that, The first data processing module is also used for: The adjustment ratio is obtained based on the pre-oxygen stability index and the first preset threshold. Obtain the standard steady-state range, and reduce the standard steady-state range according to the adjustment ratio to form the post-oxygen steady-state range.

9. An electronic device, characterized in that, include: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the air-fuel ratio control method according to any one of claims 1 to 6.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the air-fuel ratio control method according to any one of claims 1 to 6.

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