Method, device and equipment for avoiding flameout of engine and storage medium

Abstract

The invention discloses a method, device and equipment for avoiding engine flameout and a storage medium, and the method comprises the steps that the clamping stagnation state of a mixing valve is judged according to the current target opening degree and the actual opening degree; according to the clamping stagnation state of the mixing valve, PID control calculation is conducted on the opening degree error between the current target opening degree and the actual opening degree; and when it is judged that the mixing valve is opened in the stable clamping stagnation state, an integral item of PID control over the opening degree error is reset so as to avoid engine flameout. The method aims at solving the problems that in the prior art, due to the fact that a mixing valve of a low-pressure EGR system forms duty ratio overshoot when the mixing valve is opened due to clamping stagnation, the mixing valve is fully closed, external air does not enter an air cylinder, and an engine flames out or shakes, the method can effectively recognize that the mixing valve enters the clamping stagnation opening state from the clamping stagnation state, and the working efficiency of the low-pressure EGR system is improved. PID control adjustment is carried out on the mixing valve, and the problems of engine flameout and jittering caused by overshoot of the mixing valve are solved.

Description

Technical Field

[0001] The present application relates to the field of vehicle engine technology, and in particular to a method, device, equipment and storage medium for preventing engine stalling. Background Art

[0002] The EGR system, or Exhaust Gas Recirculation (EGR), is an effective technology for reducing the nitrogen oxide (NOx) content in internal combustion engine emissions. Although the existing low-pressure EGR system technology has significant advantages over the high-pressure EGR system in reducing nitrogen oxide emissions and improving fuel economy, it still has some shortcomings, which will have a certain impact on engine performance, reliability and vehicle driving safety.

[0003] Since the exhaust gas recirculation gas path of the low-pressure EGR system is relatively long, the exhaust gas may increase resistance during the transmission process, resulting in a decrease in intake pressure. When the exhaust gas pressure is not enough to overcome the pressure in the cylinder, the exhaust gas will not be able to enter the cylinder smoothly, thus affecting the normal operation of the EGR system. This problem needs to be solved by precise mixing valve control, but it increases the complexity and cost of the system. The mixing valve plays a vital role in the low-pressure EGR system, and the precise control of its opening is essential to ensure that the exhaust gas can enter the cylinder smoothly. Proportional-Integral-Derivative Controller (PID): In the control system, the PID controller is a common method that can be used to control the mixing valve of the low-pressure EGR system. The PID controller adjusts the control input by calculating the proportional (P), integral (I) and derivative (D) terms of the deviation (i.e., the difference between the actual output and the desired output), thereby reducing the deviation and maintaining the desired output. However, the control of the mixing valve involves multiple factors, such as engine operating conditions, exhaust gas temperature and pressure, which makes the control system complex and difficult to adjust accurately. Once improperly controlled, the mixing valve may be fully open or fully closed, thereby affecting the normal operation of the engine. Since the low-pressure EGR system involves a long gas path and a complex control system, its response speed may be relatively slow. When the engine operating conditions change, the EGR system needs a certain amount of time to adjust the exhaust gas recirculation volume to adapt to the new operating conditions. This delay may cause a temporary decrease in engine performance or excessive emissions. Since the low-pressure EGR system involves multiple components and a complex control system, its maintenance cost may be relatively high. In particular, key components such as the mixing valve may need to be replaced or repaired once they fail or wear, increasing the cost of using the vehicle. Complex control systems and long gas paths may increase the risk of system failure. For example, a failure of the mixing valve may prevent exhaust gas from entering the cylinder or outside air from entering the engine, thereby affecting the normal operation of the engine. In addition, impurities and particulate matter in the exhaust gas may also cause blockage or wear on the EGR system, reducing the reliability of the system. Summary of the invention

[0004] The main purpose of the present application is to provide a method, device, equipment and storage medium for preventing engine stalling, aiming to solve the problem that the mixing valve of the low-pressure EGR system in the prior art is fully closed due to duty cycle overshoot formed when the mixing valve is stuck and flushed, so that the outside air does not enter the cylinder, causing the engine to stall or jitter. The method of the present application can effectively identify the mixing valve from entering the stuck and flushed state, and adjust the PID control strategy in time when the stuck state is flushed, thereby avoiding the engine stalling and jittering caused by mixing valve overshoot.

[0005] To achieve the above object, the present application provides a method for preventing engine stalling, the method for preventing engine stalling comprising:

[0006] According to the current target opening and the actual opening, the stuck state of the mixing valve is judged;

[0007] According to the stuck state of the mixing valve, a PID control calculation is performed on the opening error between the current target opening and the actual opening;

[0008] When it is determined that the stable stuck state of the mixing valve is opened, the integral term of the PID control of the opening error is reset to avoid engine stalling.

[0009] In one embodiment, the step of determining the stuck state of the mixing valve according to the current target opening and the actual opening further includes:

[0010] Determining whether the actual opening of the mixing valve is stable at a preset opening position;

[0011] Calculating the opening error according to the current target opening and the actual opening;

[0012] According to the calculated current opening error, it is determined whether the actual opening of the mixing valve is in a stable stuck state.

[0013] In one embodiment, the step of judging whether the actual opening of the mixing valve is in a stable stuck state according to the calculated current opening error further includes:

[0014] Recording the time during which the actual opening of the mixing valve remains in a stable state;

[0015] When the opening error of the mixing valve meets the requirement of closed-loop control and the actual opening is maintained in a stable state for a period of time, it is determined that the mixing valve is in a non-target opening stuck state and the position is stable.

[0016] In one embodiment, the step of calculating the opening error between the current target opening and the actual opening by PID control according to the stuck state of the mixing valve further includes:

[0017] Calculating a differential term of the PID control of the opening error according to the stuck state of the mixing valve;

[0018] Calculating an integral term of the PID control of the opening error according to the stuck state of the mixing valve;

[0019] Calculating a proportional term of the PID control of the opening error according to the stuck state of the mixing valve;

[0020] The differential term of the PID control, the integral term of the PID control and the proportional term of the PID control are accumulated to obtain the PID control result of the mixing valve.

[0021] In one embodiment, when it is determined that the stable stuck state of the mixing valve is opened, the step of resetting the integral term of the PID control of the opening error to avoid engine stalling further includes:

[0022] When it is detected that the actual opening of the mixing valve changes and the change amplitude exceeds a preset threshold, it is determined that the stuck state of the mixing valve is opened;

[0023] After confirming that the stuck state of the mixing valve is cleared, the integral term in the PID control is reset and the PID control result of the mixing valve is updated to avoid engine stalling.

[0024] In one embodiment, when it is detected that the actual opening of the mixing valve changes suddenly and the change amplitude exceeds a preset threshold, the step of determining that the stuck state of the mixing valve is opened includes:

[0025] According to the stuck state of the mixing valve, recording the stuck flag position of the mixing valve at each moment;

[0026] When the stuck flag position at the previous moment is the first preset value and the flag position at the current moment is the second preset value and the change amplitude exceeds the preset threshold value, it is determined that the mixing valve is opened from the stuck state.

[0027] In one embodiment, after confirming that the stuck state of the mixing valve is cleared, the step of resetting the integral term in the PID control and updating the PID control result of the mixing valve to avoid engine stalling further includes:

[0028] Detecting the working state of the mixing valve;

[0029] After the integral of the mixing valve is reset, the mixing valve moves in the opposite direction to the target opening, and the feedforward provides the duty cycle at that moment;

[0030] Responsiveness is provided by feed-forward friction compensation so that the mixing valve remains stable after being stuck open.

[0031] In addition, to achieve the above-mentioned purpose, the present application also proposes a device for preventing engine flameout, the device for preventing engine flameout comprising:

[0032] A judgment module judges the stuck state of the mixing valve according to the current target opening and the actual opening;

[0033] An adjustment module, which performs PID control calculation on an opening error between the current target opening and the actual opening according to the stuck state of the mixing valve;

[0034] The reset module resets the integral term of the PID control of the opening error to avoid engine stalling when it is determined that the stable stuck state of the mixing valve is opened.

[0035] In addition, to achieve the above-mentioned purpose, the present application also proposes a device for preventing engine stalling, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the method for preventing engine stalling as described above.

[0036] In addition, to achieve the above-mentioned purpose, the present application also proposes a computer storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for avoiding engine stalling as described above are implemented.

[0037] The above one or more technical solutions provided by the present application may have the following advantages or at least achieve the following technical effects: The present application relates to the field of automobile engine technology, and in particular to the control problem of the mixing valve in the low-pressure EGR (exhaust gas recirculation) system, and proposes an innovative method, device, equipment and storage medium, which is intended to solve the problem of engine stalling or jittering that may be caused by the mixing valve being flushed open in a stuck state. The core of the method is to accurately judge the stuck state of the mixing valve and adjust the PID control strategy when the stuck state is flushed open to avoid engine stalling or jittering caused by overshoot of the mixing valve. The system first determines whether the mixing valve is in a stuck state based on the difference between the current target opening and the actual opening, as well as the response characteristics of the mixing valve. If the actual opening of the mixing valve stays at a fixed value for a long time and there is a significant deviation from the target opening, the system determines that the mixing valve is in a stuck state. After determining that the mixing valve is in a stuck state, the system will perform PID control calculations based on the opening error between the current target opening and the actual opening. The PID controller will output a corresponding control signal to adjust the opening of the mixing valve according to the size, rate of change and cumulative error of the error. The system continuously monitors the opening change of the mixing valve. When it is detected that the opening of the mixing valve suddenly increases and the change amplitude exceeds the preset threshold, it is determined that the stuck state of the mixing valve is flushed. After confirming that the stuck state of the mixing valve is flushed, the system immediately resets the integral term of the PID control. The reset of the integral term is to eliminate the excessive control signal caused by the integral accumulation, and to prevent the mixing valve from continuing to move in the wrong direction due to the action of the integral term after being flushed, resulting in overshoot. After the integral term is reset, the system will recalculate the output signal of the PID controller according to the new opening error. At the same time, the system will also combine strategies such as feedforward control to ensure that the opening of the mixing valve is stable near the flushing position. Avoid the spring pulling the valve body to rotate due to the total duty cycle being too small after the I term is reset. Through the method proposed in this application, the system can accurately judge the stuck state of the mixing valve, and adjust the PID control strategy in time when the stuck state is flushed, effectively avoiding the engine stalling and jitter problems caused by the overshoot of the mixing valve. This not only improves the reliability and stability of the automobile engine, but also reduces the maintenance cost and safety hazards caused by failures. This method is applicable to all automobile engines with low-pressure EGR systems, especially those with high requirements for air flow control. By integrating this method into the engine control system, the performance and safety of the engine can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0039] Figure 1 A flowchart of a first embodiment of a method for preventing engine stalling according to the present application;

[0040] Figure 2 A flow chart of a second embodiment of a method for preventing engine stalling according to the present application;

[0041] Figure 3 A flowchart of a third embodiment of the method for preventing engine stalling of the present application;

[0042] Figure 4 This is a flow chart of a fourth embodiment of the method for preventing engine stalling of the present application.

[0043] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

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

[0045] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0046] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0047] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] In the control system of the mixing valve, especially in the cylinder air mixing control of the automobile engine, the precise control of the opening of the mixing valve is very important. When the mixing valve is stuck at a smaller opening due to some reasons (such as dirt, mechanical failure, etc.), it may cause insufficient air flow and affect the engine performance. In order to cope with this situation, especially when the mixing valve is stuck and eventually opened by a larger duty cycle signal, the traditional PID (proportional-integral-differential) control algorithm may cause overshoot problems, causing the mixing valve to move excessively or even completely closed, which is extremely detrimental to the engine operation. In view of the above problems, the present invention proposes an innovative mixing valve control strategy optimization method, and the specific process is as follows:

[0049] First, the system needs to continuously monitor the difference between the actual opening of the mixing valve and the target opening, as well as the response of the mixing valve. When it is found that the opening of the mixing valve stays at a fixed value (such as less than 20%) for a long time, and there is a large deviation from the target opening, the system determines that the mixing valve is in a stuck state. By monitoring the sudden change of the mixing valve opening (such as a rapid increase from a stuck state), the system recognizes that the mixing valve has been flushed from the stuck state by a large duty cycle signal. Once a stuck-open event is identified, the system immediately sets a flag to indicate that it is currently in a special control state.

[0050] PID control is a linear control method that controls based on the deviation between the set value and the actual value. The output of the PID controller is the sum of the proportional (P), integral (I) and differential (D) of the deviation. These three terms represent different aspects of the control action:

[0051] Proportional control: The control amount is output according to the size of the deviation. The larger the deviation, the larger the control amount. Proportional control can quickly reduce the deviation, but it may avoid overshoot and oscillation.

[0052] Integral control: Integrate the deviation to eliminate the steady-state error of the system. Integral control can ensure that the system eventually stabilizes at the set value, but it may increase the response time of the system.

[0053] Differential control: Output the control amount according to the rate of change of the deviation to predict future deviations and make adjustments in advance. Differential control helps reduce overshoot and oscillation and improve system stability.

[0054] PID control algorithm adjustment. After identifying the jamming and opening, the system immediately clears the integral term in the PID control algorithm. This step is to eliminate the excessive duty cycle caused by the accumulation of the integral term to avoid overshoot. After clearing, the integral term starts to accumulate again, but the accumulation process is carried out under more cautious conditions at this time to avoid overshoot again. In the special control state after the jamming and opening, the feedforward control compensates for the spring force and friction force. Through the above compensation, the system can reduce the violent mutation of the valve body position at the moment of opening the mixing valve, and try to stabilize the mixing valve at the position opening after opening, avoiding overshoot and subsequent full closing risks. The spring force compensation and friction force compensation of the feedforward are obtained by looking up the valve opening position table based on the bench test data. The compensation of friction and spring force not only provides responsiveness, but also provides stability after the jamming and opening. To prevent the valve body from moving too much in the opposite direction of the target opening after it is identified as stuck and the I item is reset due to the total duty cycle being too small. The duty cycle control strategy after identifying the valve body entering the stuck and open state from the stuck state is used to avoid engine stalling and jitter problems caused by overshoot of the mixing valve.

[0055] Through the above method, the present application effectively solves the problem of overshoot that may occur after the mixing valve is stuck and opened, and avoids the risk of engine stalling or shaking caused by it. This method not only improves the accuracy and stability of the mixing valve control, but also ensures the reliable operation of the engine under complex working conditions, which is of great significance to improving the driving safety and overall performance of the vehicle.

[0056] This application proposes a method for preventing engine stalling in a first embodiment, please refer to Figure 1 The method for preventing engine stalling includes steps S10 to S30:

[0057] Step S10, judging the stuck state of the mixing valve according to the current target opening and the actual opening;

[0058] Step S20, performing PID control calculation on the opening error between the current target opening and the actual opening according to the stuck state of the mixing valve;

[0059] Step S30: when it is determined that the stable stuck state of the mixing valve is opened, the integral term of the PID control of the opening error is reset to avoid engine stalling.

[0060] It should be noted that in the exhaust gas recirculation (EGR) system of automobile engines, the mixing valve is a key component used to adjust the proportion of exhaust gas entering the cylinder, thereby optimizing combustion efficiency and emission performance. However, the mixing valve may be stuck in a certain position due to a variety of reasons (such as dirt, wear or mechanical failure), resulting in the inability to accurately control its opening. When the mixing valve is stuck, there will be a significant deviation between its actual opening and the target opening, which will affect the normal operation of the engine. The following is a detailed description of the above steps:

[0061] Step S10: According to the current target opening and actual opening, the stuck state of the mixing valve is judged. The first step of step S10 is to continuously monitor the target opening and actual opening of the mixing valve. The target opening is usually calculated by the engine management system (EMS) according to the current working conditions (such as speed, load, temperature, etc.) and sent to the mixing valve controller. The actual opening is the current position of the mixing valve measured by a sensor (such as a position sensor or a pressure sensor). After obtaining the target opening and the actual opening, the system needs to calculate the deviation between them. This deviation reflects the difference between the current state of the mixing valve and the target state. The calculation of the opening deviation is usually very simple, that is, subtracting the actual opening from the target opening. Next, the system will judge whether it is in a stuck state based on the opening deviation and the response characteristics of the mixing valve. The judgment basis includes that if the opening deviation continues to exceed a preset threshold (such as 5% or 10%), it may indicate that the mixing valve has a stuck problem. The duration of the deviation is also an important indicator. If the deviation remains unchanged or changes very little for a long time (such as a few seconds or minutes), it may mean that the mixing valve has stuck. The system also considers the response speed of the mixing valve to the control signal. If the mixing valve fails to respond in time after receiving the control signal (such as the response time exceeds the preset threshold), it may indicate that it is stuck or faulty. In addition to the above-mentioned judgment methods based on opening deviation and response characteristics, the system can also use other auxiliary means to improve the accuracy of identifying the stuck state. Temperature monitoring can indirectly determine whether it has a stuck problem by monitoring the temperature changes around the mixing valve. If the mixing valve is in a certain position for a long time and the temperature rises or falls abnormally, it may indicate that it has stuck. The mixing valve may produce abnormal vibration or noise when it is stuck. By monitoring these signals, the system can further confirm the stuck state of the mixing valve.

[0062] Determine whether the valve body is currently stable at a certain opening. When , the cumulative timing begins. Let the initial value t accum(0) = 0, t accum (z) = t accum (z-1)+T; The timer is reset, i.e. t accum (z) = 0. is the current moment. The actual opening of the mixing valve is e stable Represents the position fluctuation tolerance (calibratable) of the valve body at the current stable position. That is, when the actual position fluctuation of the mixing valve is less than the tolerance, the mixing valve is considered to be temporarily stable at the current opening position.

[0063] Calculate the opening error based on the current actual opening and target opening:

[0064]

[0065] in, is the current target opening, e open (z) is the difference between the current target opening and the actual opening.

[0066] when And t accum (z)>=t stucksteady When the valve body is determined to be stuck at a non-target opening and maintain a stable position, the Stucksteady flag is set to 1. Otherwise, Stucksteady is set to 0.

[0067] e allowed is the allowable error, that is, when When t stucksteady The time for the position to stabilize, that is, when the valve body opening is kept in a stable state for more than t stucksteady It is considered that the state of the valve body during this period is positionally stable.

[0068] Step S20: According to the stuck state of the mixing valve, the opening error between the current target opening and the actual opening is calculated by PID control. Once the stuck state of the mixing valve is determined, the system needs to adopt a corresponding control strategy to reduce the opening error so that the actual opening of the mixing valve is as close to the target opening as possible. PID control is a commonly used feedback control method, which calculates the control signal according to the current error (i.e., the deviation between the target opening and the actual opening) to adjust the output of the controlled object. Proportional control outputs a control signal according to the size of the current error. The larger the error, the stronger the control signal. Proportional control can quickly reduce the error, but may cause overshoot and oscillation. Integral control integrates the error to eliminate the steady-state error of the system. Integral control can ensure that the system eventually stabilizes at the target value, but may increase the response time of the system. Differential control outputs a control signal according to the rate of change of the error to predict future errors and make adjustments in advance. Differential control helps to reduce overshoot and oscillation and improve the stability of the system. Before PID control is performed, the parameters of the PID controller (i.e., the proportional coefficient Kp, the integral coefficient Ki, and the differential coefficient Kd) need to be set. The selection of these parameters has an important impact on the performance of the system. Generally speaking, these parameters need to be determined through experiments and experience. After determining the parameters of the PID controller, the system can calculate the control signal based on the current opening error.

[0069] In the case of a stuck mixing valve, the parameters of the PID controller may need to be adjusted to accommodate this special situation. In a stuck state, a too large proportional coefficient may cause the mixing valve to overshoot after being flushed. Therefore, Kp can be appropriately reduced to reduce the response speed of the system and avoid overshoot. Although integral control may increase the response time of the system, in a stuck state, increasing Ki can help eliminate steady-state errors caused by stuck. Differential control can predict future errors and make adjustments in advance. In a stuck state, introducing differential control can help reduce overshoot and oscillation caused by flushing stuck.

[0070] Step S30: When it is determined that the stable stuck state of the mixing valve is opened, the integral term of the PID control of the opening error is reset to avoid engine stalling. When the stable stuck state of the mixing valve is opened by a larger control signal (such as a larger duty cycle), due to the effect of the integral term, the PID controller may continue to output an excessive control signal, resulting in excessive movement of the mixing valve and overshoot. This overshoot may cause the mixing valve to close completely, thereby preventing outside air from entering the cylinder, causing the engine to stall or shake. In order to avoid this situation, the system needs to reset the integral term of the PID control when the mixing valve is opened. The system needs to continuously monitor the opening change of the mixing valve and determine whether it has been opened from the stuck state. This can usually be achieved by monitoring the change in the opening error. If the opening error decreases rapidly in a short period of time (such as from a larger positive value to a smaller positive or negative value), it may indicate that the mixing valve has been opened. The reset of the integral term is to eliminate the excessive control signal caused by the accumulation of integrals. After the mixing valve is cleared from the stuck state, the system immediately clears the integral term of the PID controller and restarts the accumulation. This ensures that after the mixing valve is cleared, the PID controller will not continue to output an excessive control signal due to the action of the integral term, thereby avoiding the risk of overshoot and engine stalling. The reset of the integral term can be achieved through software programming. When the system determines that the mixing valve has been cleared from the stuck state, it immediately restarts the accumulation of the integral term, but the accumulation process is carried out under more cautious conditions at this time to avoid overshoot again. After the integral term is reset, the system also needs to adjust the output signal of the PID controller according to the new opening error. At this time, the system can combine strategies such as feedforward control to ensure that the opening of the mixing valve can be stabilized near the target opening. Feedforward control can provide a pre-adjustment amount based on system experience or model prediction, so as to control the opening of the mixing valve more smoothly.

[0071] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 2 In this embodiment, the step of judging the stuck state of the mixing valve according to the current target opening and the actual opening also includes:

[0072] Step S11, determining whether the actual opening of the mixing valve is stable at a preset opening position;

[0073] Step S12, calculating the opening error according to the current target opening and the actual opening;

[0074] Step S13 determines whether the actual opening of the mixing valve is in a stable stuck state according to the calculated current opening error.

[0075] Specifically, in this embodiment, the mixing valve is a key component for regulating the exhaust gas flow, and its state has an important impact on the performance and emissions of the engine. When the mixing valve is stuck, there will be a significant difference between its actual opening and the target opening, which will affect the normal operation of the engine. Therefore, accurately judging the stuck state of the mixing valve is crucial to ensuring the stability and reliability of the engine. The following is a detailed description of the above steps:

[0076] Step S11: Determine whether the actual opening of the mixing valve is stable at the preset opening position. First, the system needs to continuously monitor the actual opening of the mixing valve. This is usually achieved by a position sensor installed on the mixing valve, which can measure and feedback the opening information of the mixing valve in real time. The preset opening position refers to the opening that the mixing valve should reach under normal working conditions. This value is usually calculated by the engine management system (EMS) based on the current working conditions (such as speed, load, temperature, etc.) and stored in the control unit. After obtaining the actual opening of the mixing valve, the system needs to determine whether it is stable at the preset opening position. This can be achieved by comparing the difference between the actual opening and the preset opening. If the difference between the two is within the preset tolerance range (such as ±1% or ±2%), and this difference remains unchanged for a long time (such as a few seconds or minutes), it can be considered that the actual opening of the mixing valve is stable. In addition to the above-mentioned judgment method based on the difference in opening, the system can also use other auxiliary means to improve the accuracy of the judgment. For example, the temperature change or vibration around the mixing valve can be monitored to determine whether it is stuck or faulty.

[0077] Step S12: Calculate the opening error based on the current target opening and the actual opening. The target opening refers to the ideal opening that the mixing valve should reach, calculated by the engine management system based on the current operating conditions. This value is usually stored in the control unit and used to compare with the actual opening. After obtaining the target opening and the actual opening, the system needs to calculate the error between them. This error reflects the difference between the current state and the target state of the mixing valve, and is an important basis for determining whether the mixing valve is stuck. The calculation of the opening error is usually very simple, which is to subtract the difference between the target opening and the actual opening. In order to determine whether the opening error is significant, the system needs to set an error threshold. This threshold is usually determined based on the characteristics of the mixing valve and the requirements of the engine. If the opening error exceeds this threshold, it may indicate that the mixing valve has a stuck problem.

[0078] Step S13: According to the calculated current opening error, determine whether the actual opening of the mixing valve is in a stable stuck state. After obtaining the opening error, the system needs to determine whether the error is stable. If the opening error remains unchanged or changes very little (such as the range of change is within the preset tolerance range) for a long time (such as a few seconds or minutes), the opening error can be considered to be stable. In addition to judging the stability of the opening error, the system also needs to comprehensively judge whether it is in a stable stuck state in combination with the stability of the actual opening of the mixing valve. If the actual opening of the mixing valve is stable at a certain position, and the opening error also remains stable and significant (exceeding the preset error threshold), it can be considered that the mixing valve is in a stable stuck state. Once it is determined that the mixing valve is in a stable stuck state, the system needs to take appropriate measures to deal with it. This may include adjusting the control strategy, issuing an alarm signal, or taking other necessary measures to ensure the normal operation of the engine.

[0079] It is particularly important to note that in actual applications, it is not a simple matter to determine whether the mixing valve is stuck. This is because the state of the mixing valve may be affected by many factors, such as temperature, pressure, vibration, etc. Therefore, the system needs to comprehensively consider information from multiple aspects to make an accurate judgment. In addition, the dynamic characteristics of the mixing valve also need to be considered to determine whether it is stuck. For example, at the moment when the mixing valve is opened from a stuck state, its actual opening may change rapidly, resulting in a sudden decrease in the opening error. At this point, the system needs to be able to respond quickly and adjust the control strategy to avoid problems such as engine stalling or jitter.

[0080] Furthermore, in this embodiment, the step of judging whether the actual opening of the mixing valve is in a stable stuck state according to the calculated current opening error further includes:

[0081] Recording the time during which the actual opening of the mixing valve remains in a stable state;

[0082] When the opening error of the mixing valve meets the requirement of closed-loop control and the actual opening is maintained in a stable state for a period of time, it is determined that the mixing valve is in a non-target opening stuck state and the position is stable.

[0083] Specifically, in this embodiment, accurately judging whether the mixing valve is in a stable non-target opening stuck state is crucial to ensuring the stability and reliability of the engine. The following is a detailed description of the judgment process, including recording the time when the actual opening of the mixing valve remains in a stable state, and judging that the mixing valve is in a non-target opening stuck state and the position is stable when the closed-loop control requirements are met.

[0084] First, the system needs to continuously monitor the actual opening changes of the mixing valve. This is usually achieved by a position sensor installed on the mixing valve, which can measure and feedback the opening information of the mixing valve in real time. The system needs to record the actual opening data at each time point for subsequent analysis. In order to determine whether the actual opening of the mixing valve is in a stable state, the system needs to set a stable state standard. This standard is usually determined based on the range of change of the actual opening and the length of time. For example, if the range of change of the actual opening within a period of time (such as a few seconds or minutes) is less than the preset tolerance (such as ±1% or ±2%), it can be considered that the actual opening of the mixing valve is in a stable state. Once it is determined that the actual opening of the mixing valve is in a stable state, the system needs to start recording this time. This time is calculated from the first time the actual opening meets the stable state standard until the actual opening no longer meets the stable state standard. This length of time is one of the important bases for judging whether the mixing valve is in a stable stuck state.

[0085] Before determining whether the mixing valve is in a non-target opening stuck state, the system needs to calculate the opening error of the mixing valve. The opening error refers to the difference between the actual opening of the mixing valve and the target opening. This difference reflects the difference between the current state of the mixing valve and the target state, and is an important basis for determining whether the mixing valve is stuck. Closed-loop control means that the system adjusts the control input (such as control current or voltage) according to the feedback signal (such as the actual opening) to achieve the desired output (such as the target opening). When determining whether the mixing valve is in a non-target opening stuck state, the system needs to consider the requirements of closed-loop control. If the opening error of the mixing valve is within the tolerance range of the closed-loop control (that is, the opening error is less than the preset threshold), it can be considered that the opening of the mixing valve meets the requirements of closed-loop control. On the premise that the opening error of the mixing valve meets the requirements of closed-loop control, the system needs to further determine whether the mixing valve is in a non-target opening stuck state. This can be achieved by comparing the actual opening with the target opening. If there is a significant difference between the actual opening and the target opening (i.e. the opening error exceeds the preset threshold), and this difference remains unchanged or changes very little over a long period of time (i.e. the recorded steady state time), the mixing valve can be considered to be in a non-target opening stuck state. In addition to determining whether the mixing valve is in a non-target opening stuck state, the system also needs to determine whether the position of the mixing valve is stable. This can be achieved by analyzing the changes in the actual opening during the steady state time. If the actual opening remains essentially unchanged during the steady state time (i.e. the range of change is less than the preset tolerance), the position of the mixing valve can be considered to be stable.

[0086] Based on the first embodiment and / or the second embodiment of the present application, in the third embodiment of the present application, the same or similar contents as those in the first and second embodiments above can be referred to the above description, and will not be described in detail later. Figure 3In this embodiment, step S20, the step of performing PID control calculation on the opening error between the current target opening and the actual opening according to the stuck state of the mixing valve, further includes:

[0087] Step S21, calculating the differential term of the PID control of the opening error according to the stuck state of the mixing valve;

[0088] Step S22, calculating the integral term of the PID control of the opening error according to the stuck state of the mixing valve;

[0089] Step S23, calculating a proportional term of the PID control of the opening error according to the stuck state of the mixing valve;

[0090] Step S24, accumulating the differential term of the PID control, the integral term of the PID control and the proportional term of the PID control to obtain the PID control result of the mixing valve.

[0091] Specifically, in the present embodiment, according to the stuck state of the mixing valve, a step of performing PID control calculation on the opening error between the current target opening and the actual opening is performed. PID control is a commonly used control algorithm that reduces the error between the target value and the actual value by adjusting the control input. In the control of the mixing valve, PID control can help us dynamically adjust the control strategy according to the stuck state of the mixing valve to achieve precise control of the mixing valve. When the mixing valve is stuck, there will be a significant difference between its actual opening and the target opening, which will affect the normal operation of the engine. In order to deal with this situation, we need to perform PID (proportional-integral-differential) control calculation on the opening error between the target opening and the actual opening according to the stuck state of the mixing valve to achieve precise control of the mixing valve. The following are detailed steps and instructions:

[0092] Step S21: Calculate the differential term of the PID control of the opening error. The differential term is mainly used in PID control to predict the changing trend of the error and adjust the control input according to this trend to eliminate potential errors in advance. In the control of the mixing valve, the differential term can help us adjust the control strategy according to the changing rate of the opening error, so as to achieve a rapid response to the mixing valve. The calculation of the differential term is usually based on the changing rate of the opening error. When calculating the differential term, we need to consider the stuck state of the mixing valve. If the mixing valve is in a stuck state, the changing rate of the opening error may be limited, resulting in inaccurate calculation results of the differential term. Therefore, we need to adjust the differential gain according to the stuck state of the mixing valve to ensure that the differential term can accurately reflect the changing trend of the opening error.

[0093] Step S22: Calculate the integral term of the PID control of the opening error. The integral term is mainly used in PID control to eliminate the accumulated error to ensure that the system can reach a stable state. In the control of the mixing valve, the integral term can help us adjust the control input according to the accumulation of the opening error, so as to achieve precise control of the mixing valve. The calculation of the integral term is usually based on the cumulative value of the opening error. When calculating the integral term, we also need to consider the stuck state of the mixing valve. If the mixing valve is in a stuck state, the accumulation speed of the opening error may be limited, resulting in inaccurate calculation results of the integral term. Therefore, we need to adjust the integral gain according to the stuck state of the mixing valve to ensure that the integral term can accurately reflect the accumulation of the opening error.

[0094] Step S23: Calculate the proportional term of the PID control of the opening error. The proportional term is mainly used in PID control to directly reduce the error. In the control of the mixing valve, the proportional term can help us adjust the control input according to the current opening error, so as to achieve a fast response to the mixing valve. The calculation of the proportional term is usually based on the current opening error. When calculating the proportional term, we also need to consider the stuck state of the mixing valve. If the mixing valve is in a stuck state, the opening error may persist, resulting in an excessively large calculation result of the proportional term. Therefore, we need to adjust the proportional gain according to the stuck state of the mixing valve to ensure that the proportional term can appropriately reflect the current opening error.

[0095] Step S24: Accumulate the differential term, integral term and proportional term of the PID control to obtain the PID control result of the mixing valve. After calculating the differential term, integral term and proportional term of the PID control, we need to add them up to obtain the PID control result of the mixing valve. This control result will be used to adjust the control input of the mixing valve to achieve precise control of the mixing valve. When accumulating each PID term, we need to consider the dynamic characteristics of the mixing valve. For example, the response time and hysteresis effect of the mixing valve will affect the result of the PID control. Therefore, we need to adjust the parameters of the PID control according to the dynamic characteristics of the mixing valve to ensure that the PID control can achieve precise control of the mixing valve. Finally, the accumulated PID control result is output to the control unit of the mixing valve to adjust the control input of the mixing valve. This control result will directly affect the actual opening of the mixing valve, thereby achieving precise regulation of the engine exhaust flow.

[0096] Based on the first embodiment and / or the second embodiment and / or the third embodiment of the present application, in the fourth embodiment of the present application, the same or similar contents as those of the above-mentioned first embodiment, second embodiment and third embodiment can refer to the above introduction and will not be repeated later. Figure 4In this embodiment, step S30, when it is determined that the mixing valve is in a stable stuck state and is opened, resetting the integral term of the PID control of the opening error to avoid engine stalling, further includes:

[0097] Step S31, when it is detected that the actual opening of the mixing valve changes and the change amplitude exceeds a preset threshold, it is determined that the stuck state of the mixing valve is opened;

[0098] Step S32, after confirming that the mixing valve is in a stuck state and is cleared, resetting the integral term in the PID control and updating the PID control result of the mixing valve to avoid engine stalling.

[0099] Specifically, in this embodiment, when it is determined that the mixing valve is in a stable stuck state and is cleared, the PID control integral term is reset to avoid engine stalling. The purpose of this step is to eliminate the accumulated error by resetting the integral term of the PID control after the mixing valve is in a stuck state and to avoid engine stalling due to improper mixing valve control. The following are the detailed steps and instructions:

[0100] Step S31: monitor the actual opening change of the mixing valve and determine whether the stuck state is cleared. To determine whether the stable stuck state of the mixing valve is cleared, it is first necessary to monitor the actual opening change of the mixing valve. This is usually achieved by a position sensor installed on the mixing valve, which can measure and feedback the opening information of the mixing valve in real time. In order to accurately determine whether the stuck state of the mixing valve is cleared, we need to set a preset threshold value of the change amplitude. This threshold value can be determined based on factors such as the normal working range of the mixing valve, the operating state of the engine, and the accuracy of the control system. After monitoring the change in the actual opening of the mixing valve, we need to determine whether the change amplitude exceeds the preset threshold value. If the change amplitude exceeds the threshold value, we can assume that the stuck state of the mixing valve has been cleared. This is because the actual opening of the mixing valve usually remains unchanged or changes very little when it is stuck. When the stuck state is cleared, the actual opening of the mixing valve will change significantly, and this change amplitude will usually exceed the preset threshold value.

[0101] Step S32: Reset the PID control integral term and update the PID control result. After confirming that the mixing valve stuck state is cleared, we need to reset the integral term in the PID control. The integral term is used to eliminate the accumulated errors in the PID control, but when the mixing valve is in a stuck state, the integral term may accumulate large errors because it cannot accurately reflect the changes in the actual opening. Therefore, after the stuck state is cleared, we need to reset the integral term to eliminate these accumulated errors. After resetting the integral term, we need to recalculate the result of the PID control based on the current opening error. This new control result will be used to adjust the control input of the mixing valve to achieve accurate control of the mixing valve. When updating the PID control result, we need to consider factors such as the dynamic characteristics of the mixing valve and the operating status of the engine to ensure the accuracy and stability of the control result. By resetting the integral term and updating the PID control result, we can avoid the engine from stalling due to improper control of the mixing valve. This is because when the mixing valve stuck state is cleared, if the PID control is not properly adjusted, the actual opening of the mixing valve may continue to deviate from the target opening, resulting in engine performance degradation or even stalling. By resetting the integral term and updating the PID control result, we can make the actual opening of the mixing valve follow the target opening as quickly as possible, thereby maintaining stable operation of the engine.

[0102] When implementing step S30, we need to monitor the actual opening change of the mixing valve in real time and respond immediately after detecting that the stuck state is cleared. This requires the control system to have high real-time performance and response speed to ensure that it can be adjusted in time when the stuck state of the mixing valve is cleared. The setting of the preset threshold is crucial for accurately judging whether the stuck state of the mixing valve is cleared. If the threshold is set too low, it may lead to misjudgment; if the threshold is set too high, the judgment may be delayed. Therefore, we need to reasonably set the preset threshold based on factors such as the normal working range of the mixing valve, the operating state of the engine, and the accuracy of the control system. When updating the PID control results, we need to consider the dynamic characteristics of the mixing valve. For example, the response time and hysteresis effect of the mixing valve will affect the results of PID control. Therefore, we need to adjust the parameters of PID control (such as proportional gain, integral gain, differential gain, etc.) according to the dynamic characteristics of the mixing valve to ensure that PID control can achieve accurate control of the mixing valve. When resetting the integral term, we need to pay attention to avoid the problem of integral saturation. Integral saturation refers to the phenomenon that the integral term cannot be increased or decreased after accumulating to a certain limit value. If the integral term is saturated before resetting, the control system may not be able to respond quickly to changes in the actual opening after resetting. Therefore, when resetting the integral term, we need to determine whether it is necessary to attenuate or limit the integral term first based on the actual situation. In the process of implementing step S30, we also need to continuously monitor the state of the engine. If the engine has an abnormal situation (such as power loss, excessive emissions, etc.), we need to make timely adjustments and processing to ensure the stability and reliability of the engine. At this time, the duty cycle control calculation is:

[0103] PWM(z)=PWM PID +PWM FF

[0104] PWM(z) is the calculated duty cycle, PWM PID is the duty cycle controlled by PID feedback, PWM FF is the duty cycle of the feedforward control.

[0105] PWM(z)=K P *e open (z)+k d (e open (z)-e open (z-1) / T)

[0106] Under ideal conditions, the driving force provided by the feedforward control can just overcome the spring tension and friction, avoiding the valve body from moving too much in the opposite direction of the target opening due to insufficient duty cycle at the moment of the punch opening. PID The calculated duty cycle provides, while at a smaller opening, eopen (z) is not large, then PWM PID The value of is not large. Therefore, at the moment of breaking the jam, the valve body will only move toward the target opening with a small acceleration. It will not cause overshoot due to excessive duty cycle.

[0107] Further, in this embodiment, when it is monitored that the actual opening of the mixing valve changes and the change amplitude exceeds a preset threshold, the step of determining that the stuck state of the mixing valve is opened includes:

[0108] According to the stuck state of the mixing valve, recording the stuck flag position of the mixing valve at each moment;

[0109] When the stuck flag position at the previous moment is the first preset value and the flag position at the current moment is the second preset value and the change amplitude exceeds the preset threshold value, it is determined that the mixing valve is opened from the stuck state.

[0110] Specifically, in this embodiment, in order to timely determine whether the mixing valve is unstuck, we need to take a series of monitoring and judgment steps. This includes recording the mixing valve's stuck flag and determining whether the mixing valve is unstuck according to the flag and the change amplitude. The purpose of this step is to ensure the stable operation of the engine through real-time monitoring and judgment when the mixing valve may be stuck. The following is a detailed description of the above steps:

[0111] In order to track the stuck state of the mixing valve, we need to define a stuck flag. This flag can be a binary variable, which is used to indicate whether the mixing valve is currently in a stuck state. For example, we can set the flag to 0 to indicate that the mixing valve is not stuck, and set it to 1 to indicate that the mixing valve is stuck. In the actual operation process, we need to update the state of the stuck flag in real time according to the actual opening change of the mixing valve and the judgment of the control system. This is usually achieved through the logical judgment inside the control system. When it is detected that the actual opening of the mixing valve remains unchanged for a long time or changes very little, and there is a large deviation from the target opening, it can be considered that the mixing valve is in a stuck state, and the stuck flag is set to 1. On the contrary, when the mixing valve can normally follow the target opening change, the stuck flag can be set to 0. When judging whether the mixing valve is opened from the stuck state, we need to consider two conditions: one is the state of the stuck flag at the previous moment, and the other is the state of the flag at the current moment and the change range of the actual opening. The stuck flag at the previous moment is the first preset value (for example, 1): This means that the mixing valve was in a stuck state at the previous moment.

[0112] The current flag is a second preset value (e.g., 0) and the change amplitude exceeds the preset threshold: This indicates that the mixing valve is no longer in a stuck state at the current moment, and its actual opening has changed significantly. The preset threshold of the change amplitude can be determined based on factors such as the normal working range of the mixing valve, the operating state of the engine, and the accuracy of the control system. In the actual judgment process, we need to first obtain the stuck flag state at the previous moment and the current moment, and then compare whether the change amplitude of the actual opening exceeds the preset threshold. If the above two conditions are met, we can assume that the mixing valve has been opened from the stuck state.

[0113] During the judgment process, we need to ensure the real-time and accuracy of the control system so that the state change of the mixing valve can be detected in time. The setting of the preset threshold is crucial to accurately determine whether the mixing valve is opened from the stuck state. If the threshold is set too low, it may lead to misjudgment; if the threshold is set too high, the judgment may be delayed. Therefore, we need to reasonably set the preset threshold according to the actual situation. In order to implement step S31, we need a real-time monitoring system to continuously track the state of the mixing valve. This system may include sensors, data acquisition modules, logic judgment modules and other parts. The sensor is used to measure the actual opening of the mixing valve in real time; the data acquisition module is used to input the sensor data into the control system; the logic judgment module determines whether the mixing valve is in a stuck state and whether it is opened from the stuck state according to the preset algorithms and rules. Assume that at a certain moment T1, the stuck flag of the mixing valve is 1, indicating that the mixing valve is in a stuck state. At the next moment T2, we detect that the actual opening of the mixing valve has changed significantly (for example, from 20% to 60%), and the stuck flag has become 0. At the same time, this change exceeds the preset threshold (for example, 30%). In this case, we can assume that the mixing valve has been flushed from the stuck state.

[0114] Other embodiments or specific implementations of the device for preventing engine stalling of the present application can refer to the above-mentioned method embodiments, which will not be described in detail here.

[0115] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0116] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0117] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory / random access memory, a disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0118] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preventing engine stalling, characterized in that: The method for preventing engine stalling comprises: According to the current target opening and the actual opening, the stuck state of the mixing valve is judged; According to the stuck state of the mixing valve, a PID control calculation is performed on the opening error between the current target opening and the actual opening; When it is determined that the stable stuck state of the mixing valve is opened, the integral term of the PID control of the opening error is reset to avoid engine stalling.

2. The method according to claim 1, characterized in that The step of judging the stuck state of the mixing valve according to the current target opening and the actual opening also includes: Determining whether the actual opening of the mixing valve is stable at a preset opening position; Calculating the opening error according to the current target opening and the actual opening; According to the calculated current opening error, it is determined whether the actual opening of the mixing valve is in a stable stuck state.

3. The method according to claim 2, characterized in that The step of judging whether the actual opening of the mixing valve is in a stable stuck state according to the calculated current opening error further includes: Recording the time during which the actual opening of the mixing valve remains in a stable state; When the opening error of the mixing valve meets the requirement of closed-loop control and the actual opening is maintained in a stable state for a period of time, it is determined that the mixing valve is in a non-target opening stuck state and the position is stable.

4. The method according to claim 3, characterized in that The step of performing PID control calculation on the opening error between the current target opening and the actual opening according to the stuck state of the mixing valve further includes: Calculating a differential term of the PID control of the opening error according to the stuck state of the mixing valve; Calculating an integral term of the PID control of the opening error according to the stuck state of the mixing valve; Calculating a proportional term of the PID control of the opening error according to the stuck state of the mixing valve; The differential term of the PID control, the integral term of the PID control and the proportional term of the PID control are accumulated to obtain the PID control result of the mixing valve.

5. The method according to claim 4, characterized in that The step of resetting the integral term of the PID control of the opening error to avoid engine stalling when it is determined that the stable stuck state of the mixing valve is opened includes: When it is detected that the actual opening of the mixing valve changes and the change amplitude exceeds a preset threshold, it is determined that the stuck state of the mixing valve is opened; After confirming that the stuck state of the mixing valve is cleared, the integral term in the PID control is reset and the PID control result of the mixing valve is updated to avoid engine stalling.

6. The method according to claim 5, characterized in that The step of determining that the stuck state of the mixing valve is opened when it is monitored that the actual opening of the mixing valve changes and the change amplitude exceeds a preset threshold value comprises: According to the stuck state of the mixing valve, recording the stuck flag position of the mixing valve at each moment; When the stuck flag position at the previous moment is the first preset value and the flag position at the current moment is the second preset value and the change amplitude exceeds the preset threshold value, it is determined that the mixing valve is opened from the stuck state.

7. The method according to claim 6, characterized in that The step of resetting the integral term in the PID control and updating the PID control result of the mixing valve to avoid engine stalling after confirming that the mixing valve is in a stuck state and being cleared also includes: Detecting the working state of the mixing valve; After the integral of the mixing valve is reset, the mixing valve moves in the opposite direction to the target opening, and the feedforward provides the duty cycle at that moment; Responsiveness is provided by feed-forward friction compensation so that the mixing valve remains stable after being stuck open.

8. A device for preventing engine stalling, characterized in that: The device for preventing engine flameout comprises: A judgment module judges the stuck state of the mixing valve according to the current target opening and the actual opening; An adjustment module, which performs PID control calculation on an opening error between the current target opening and the actual opening according to the stuck state of the mixing valve; The reset module resets the integral term of the PID control of the opening error to avoid engine stalling when it is determined that the stable stuck state of the mixing valve is opened.

9. A device for preventing engine stalling, characterized in that: The device for preventing engine stalling comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the method for preventing engine stalling as claimed in any one of claims 1 to 7 when executed by the processor.

10. A computer storage medium, characterized in that: The computer storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for avoiding engine stalling according to any one of claims 1 to 7.

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