Control method and apparatus for Anti-stall exhaust gas recirculation system, electronic device, and storage medium

Abstract

The present application provides a control method for an anti-stall exhaust gas recirculation (EGR) system, comprising: on the basis of a pre-calibrated and pre-stored first correspondence, determining a theoretical temperature after intercooling that corresponds to an acquired actual ambient temperature, and correspondingly adjusting a cooling flow rate of an intercooler, so that the actual temperature of engine intake gas intercooled by the intercooler approaches said theoretical temperature, but a temperature difference still exists between said theoretical temperature and said actual temperature; further determining, on the basis of a pre-calibrated and pre-stored second correspondence, an EGR correction coefficient corresponding to the temperature difference and an engine load; and correcting an EGR rate on the basis of the EGR correction coefficient to obtain a target EGR rate, and controlling an EGR valve on the basis of the target EGR rate.

Description

Control methods, devices, electronic equipment, and storage media for flameout prevention exhaust gas recirculation systems

[0001] This disclosure claims priority to Chinese Patent Application No. 202510105523.0, filed on January 23, 2025, entitled “Control Method and Apparatus for Flameout Prevention Exhaust Gas Recirculation System”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of engine control, and in particular to a control method and apparatus for an exhaust gas recirculation system to prevent engine shutdown. Background Technology

[0003] In order to reduce vehicle fuel consumption and meet higher emission standards, EGR (Exhaust Gas Recirculation) systems, which recirculate exhaust gases back to the engine, are widely used in vehicles equipped with gasoline engines.

[0004] EGR systems can utilize molecules with high specific heat capacities, such as carbon dioxide and water, to increase the specific heat ratio of the air-fuel mixture in the cylinder, thereby improving the engine's Otto thermal efficiency. At the same time, carbon dioxide and water can also lower the cylinder temperature and reduce the tendency for knocking, which not only improves combustion efficiency but also reduces nitrogen oxide emissions.

[0005] However, in turbocharged gasoline engines, when the EGR operates under high load, the intake manifold pressure increases, and the dew point of water vapor also rises accordingly, making it easy for liquid water to condense. When the condensed liquid water exceeds the tolerable critical value for stable combustion in the cylinder, the engine combustion becomes unstable, resulting in engine stalling, which in turn leads to excessive emissions. Summary of the Invention

[0006] In view of this, this application provides a control method for an exhaust gas recirculation (EGR) system to prevent engine stalling and ensure stable engine operation.

[0007] On the one hand, this application provides a control method for an EGR system to prevent flameout, the method comprising:

[0008] Obtain the actual ambient temperature.

[0009] Based on the first correspondence between the actual ambient temperature and the pre-stored ambient temperature and the theoretical temperature after intercooling, the theoretical temperature after intercooling corresponding to the actual ambient temperature is determined.

[0010] Adjust the cooling flow rate of the intercooler according to the theoretical temperature after intercooling.

[0011] Obtain the engine load and the actual temperature of the engine intake air after intercooling.

[0012] Determine the temperature difference between the theoretical temperature and the actual temperature after intercooling.

[0013] By inputting engine load and temperature difference into a pre-stored second correspondence between engine load, temperature difference, and EGR correction coefficient, the EGR correction coefficient corresponding to engine load and temperature difference is determined.

[0014] The theoretical EGR rate is corrected based on the EGR correction factor to obtain the target EGR rate.

[0015] Control the EGR valve to achieve the target EGR rate.

[0016] Alternatively, the method may further include, prior to obtaining the ambient temperature:

[0017] The initial values ​​of the ambient temperature and the temperature after cooling during the test are both set to the first preset temperature threshold.

[0018] The ambient temperature is increased by a first preset temperature step, and the temperature after cooling in the test is determined for each ambient temperature until the ambient temperature reaches the second preset temperature threshold.

[0019] Based on each test ambient temperature and the corresponding intermediate cooling temperature, a first correspondence between the ambient temperature and the theoretical temperature after intermediate cooling is obtained and stored.

[0020] Among them, the cooling temperatures corresponding to each test environment temperature are determined as follows:

[0021] Set the initial engine speed to the minimum preset speed and control the EGR valve to keep the EGR rate at its maximum.

[0022] The engine speed is increased according to the preset speed step size, and the intermediate temperature after cooling corresponding to each engine speed is determined until the engine speed reaches the maximum preset speed.

[0023] The maximum intermediate temperature after cooling in the test was determined from the intermediate temperatures after cooling corresponding to each engine speed.

[0024] Among them, determining the intermediate temperature after cooling corresponding to each engine speed in the test includes:

[0025] The temperature after cooling during the test is increased by the second preset temperature step until the engine does not misfire. The temperature after cooling during the test at this point is taken as the intermediate temperature after cooling during the test.

[0026] Alternatively, the method may further include, before obtaining the actual ambient temperature:

[0027] The initial value of the test temperature difference is set to the first preset temperature difference threshold, the engine speed is set to the ideal preset speed threshold corresponding to the maximum EGR rate, the engine load is set to the first preset load threshold, and the EGR rate is set to the ideal EGR rate corresponding to the engine load.

[0028] The test temperature difference is increased by a third preset temperature step, and an EGR correction coefficient is determined for each test temperature difference until the test temperature difference reaches the second preset temperature difference threshold.

[0029] Based on each test temperature difference, the EGR correction factor corresponding to each test temperature difference, and the engine load corresponding to the EGR correction factor, a second correspondence between engine load, temperature difference, and EGR correction factor is obtained and stored.

[0030] The EGR correction factors for each test temperature difference include:

[0031] The engine load is reduced by a preset load step size, and the EGR correction coefficient corresponding to each engine load is determined until the engine load reaches the preset load threshold.

[0032] The EGR correction factor for each engine load includes:

[0033] The EGR rate is reduced by a preset EGR rate step size until the engine does not misfire. The ratio between the experimental EGR rate and the ideal EGR rate at this point is determined as the EGR correction factor.

[0034] Optionally, after determining the EGR correction factor corresponding to the temperature difference, the method further includes:

[0035] The EGR correction factor corresponding to the temperature difference is used as the first EGR correction factor.

[0036] Obtain the intake manifold temperature.

[0037] Based on the pre-stored third correspondence between intake manifold temperature and EGR correction factor, determine the second EGR correction factor corresponding to the intake manifold temperature.

[0038] The minimum value between the first EGR correction factor and the second EGR correction factor is taken as the final EGR correction factor.

[0039] The theoretical EGR rate is corrected based on the final EGR correction factor to obtain the target EGR rate.

[0040] Control the EGR valve to achieve the target EGR rate.

[0041] Optionally, after determining the EGR correction factor corresponding to the temperature difference, the method further includes:

[0042] The EGR correction factor corresponding to the temperature difference is used as the first EGR correction factor.

[0043] Obtain atmospheric pressure.

[0044] Based on the pre-stored fourth correspondence between atmospheric pressure and EGR correction factor, the third EGR correction factor corresponding to atmospheric pressure is determined.

[0045] The product of the first EGR correction factor and the third EGR correction factor is used as the final EGR correction factor.

[0046] The theoretical EGR rate is corrected based on the final EGR correction factor to obtain the target EGR rate.

[0047] Control the EGR valve to achieve the target EGR rate.

[0048] On the other hand, this application also provides a control device for an anti-flameout exhaust gas recirculation (EGR) system, the device comprising:

[0049] The acquisition module is configured to acquire the actual ambient temperature.

[0050] The determination module is configured to determine the theoretical temperature after intercooling corresponding to the actual ambient temperature based on a first correspondence between the actual ambient temperature and a pre-stored relationship between the ambient temperature and the theoretical temperature after intercooling.

[0051] The control module is configured to adjust the cooling flow rate of the intercooler based on the theoretical temperature after intercooling.

[0052] The acquisition module is also configured to acquire the engine load and the actual temperature of the engine intake air after intercooling.

[0053] The determination module is also configured to determine the temperature difference between the theoretical temperature after intercooling and the actual temperature after intercooling.

[0054] The determination module is also configured to take engine load and temperature difference as inputs and input a pre-stored second correspondence between engine load, temperature difference and EGR correction coefficient to determine the EGR correction coefficient corresponding to engine load and temperature difference.

[0055] The determination module is also configured to correct the theoretical EGR rate based on the EGR correction factor to obtain the target EGR rate.

[0056] The control module is also configured to control the EGR valve to achieve the target EGR rate.

[0057] Alternatively, the device may also include:

[0058] The setting module is configured to set the initial values ​​of both the test environment temperature and the temperature after cooling during the test to a first preset temperature threshold.

[0059] The determination module is also configured to increase the test environment temperature by a first preset temperature step and determine the test cooling temperature corresponding to each test environment temperature, until the test environment temperature reaches a second preset temperature threshold.

[0060] The determination module is also configured to obtain a first correspondence between the ambient temperature and the theoretical temperature after cooling based on each test ambient temperature and the corresponding temperature after cooling in the test, and to store the first correspondence.

[0061] The setting module is also configured to set the initial value of the engine speed to the minimum preset speed and control the EGR valve to keep the EGR rate at its maximum.

[0062] The determination module is also configured to increase the engine speed by a preset speed step and determine the intermediate temperature after cooling for each engine speed until the engine speed reaches the maximum preset speed.

[0063] The determination module is also configured to determine the maximum intermediate temperature after cooling in the test from the intermediate temperatures after cooling in the test corresponding to each engine speed.

[0064] The determination module is also configured to increase the temperature after cooling in the test by a second preset temperature step until the engine does not misfire, and the temperature after cooling in the test at this point is taken as the intermediate temperature after cooling in the test.

[0065] Alternatively, the device may also include:

[0066] The setting module is configured to set the initial value of the test temperature difference to a first preset temperature difference threshold, set the engine speed to an ideal preset speed threshold corresponding to the maximum EGR rate, set the engine load to a first preset load threshold, and set the EGR rate to an ideal EGR rate corresponding to the engine load.

[0067] The determination module is also configured to increase the test temperature difference by a third preset temperature step and determine the EGR correction coefficient corresponding to each test temperature difference until the test temperature difference reaches the second preset temperature difference threshold.

[0068] The determination module is also configured to obtain a second correspondence between engine load, temperature difference and EGR correction coefficient based on each test temperature difference, the EGR correction coefficient corresponding to each test temperature difference, and the engine load corresponding to the EGR correction coefficient, and store the second correspondence.

[0069] The determination module is also configured to reduce the engine load by a preset load step size and determine the EGR correction factor for each engine load until the engine load reaches a preset load threshold.

[0070] The determination module is also configured to decrease the EGR rate by a preset EGR rate step size until the engine does not misfire, and the ratio between the test EGR rate and the ideal EGR rate at this point is determined as the EGR correction factor.

[0071] Optionally, the determining module is further configured to use the EGR correction factor corresponding to the temperature difference as the first EGR correction factor after determining the EGR correction factor corresponding to the temperature difference.

[0072] The acquisition module is also configured to acquire the intake manifold temperature.

[0073] The determination module is also configured to determine a second EGR correction factor corresponding to the intake manifold temperature based on a third correspondence between the pre-stored intake manifold temperature and the EGR correction factor.

[0074] The determining module is also configured to use the minimum value between the first EGR correction factor and the second EGR correction factor as the final EGR correction factor.

[0075] The determination module is also configured to correct the theoretical EGR rate based on the final EGR correction factor to obtain the target EGR rate.

[0076] The control module is also configured to control the EGR valve to achieve the target EGR rate.

[0077] Optionally, after determining the EGR correction factor corresponding to the temperature difference, the determining module is further configured to use the EGR correction factor corresponding to the temperature difference as the first EGR correction factor.

[0078] The acquisition module is also configured to acquire atmospheric pressure.

[0079] The determination module is also configured to determine a third EGR correction factor corresponding to atmospheric pressure based on a pre-stored fourth correspondence between atmospheric pressure and EGR correction factor.

[0080] The determination module is also configured to use the product of the first EGR correction factor and the third EGR correction factor as the final EGR correction factor.

[0081] The determination module is also configured to correct the theoretical EGR rate based on the final EGR correction factor to obtain the target EGR rate.

[0082] The control module is also configured to control the EGR valve to achieve the target EGR rate.

[0083] The exhaust gas recirculation (EGR) system control method provided in this application, based on a pre-calibrated and stored first correspondence, determines and obtains the theoretical temperature after intercooling corresponding to the actual ambient temperature, and adjusts the cooling flow of the intercooler accordingly. This brings the actual temperature of the engine intake air after intercooling closer to the theoretical temperature. However, a temperature difference still exists between the theoretical and actual temperatures after intercooling. Furthermore, based on a pre-calibrated and stored second correspondence, an EGR correction coefficient corresponding to the temperature difference and engine load is determined. The EGR rate is then corrected using the EGR correction coefficient to obtain the target EGR rate. The EGR valve is controlled based on the target EGR rate to prevent engine stalling caused by condensed liquid water in the engine, thus ensuring stable engine operation. Attached Figure Description

[0084] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0085] Figure 1 is an architecture diagram of the anti-flameout exhaust gas recirculation (EGR) system provided in an embodiment of this application;

[0086] Figure 2 is a flowchart of the control method for the anti-flameout exhaust gas recirculation (EGR) system provided in an embodiment of this application;

[0087] Figure 3 is another flowchart of the control method of the anti-flameout exhaust gas recirculation (EGR) system provided in the embodiment of this application;

[0088] Figure 4 is another flowchart of the control method for the anti-flameout exhaust gas recirculation (EGR) system provided in the embodiment of this application;

[0089] Figure 5 is a schematic diagram of the control device for the anti-flameout exhaust gas recirculation (EGR) system provided in the embodiment of this application. Detailed Implementation

[0090] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0091] First, let's introduce the application scenarios involved in the embodiments of this application:

[0092] Low-pressure EGR is a key technology for reducing fuel consumption and improving thermal efficiency in turbocharged gasoline engines. EGR contains a large amount of water vapor, which condenses into liquid water when the temperature drops. When a large amount of liquid water enters the engine cylinder, it can lead to abnormal combustion, misfire, and consequently, worsened emissions. This invention prevents misfire by controlling the amount of condensate in the EGR. The core principle is to determine the intercooler temperature through experimental calibration. This intercooler temperature is achieved by the intercooler cryogenic cooling system. However, the cryogenic cooling system also needs to cool other vehicle components, such as the motor and motor controller. Furthermore, its physical characteristics result in a relatively long response period, leading to low-frequency fluctuations in the difference between the actual and required intercooler temperature. To address this fluctuation, the EGR is corrected through experimental calibration based on the actual intercooler temperature, thus suppressing misfire caused by excessive condensate.

[0093] This application provides a method for controlling an anti-flame-out exhaust gas recirculation (EGR) system. To better understand the control method for the anti-flame-out EGR system, the entire system is first described as follows: As shown in Figure 1, the entire anti-flame-out EGR system is divided into three main parts: engine air passage and body, intake intercooler low-temperature cooling system, and ECU control system.

[0094] The engine air passage and body include: air filter 101, EGR mixing valve 102, turbocharger compressor 103, intake water-cooled intercooler 104, throttle valve 106, intake manifold 108, engine body 109, turbocharger turbine 110, three-way catalytic converter 111, EGR cooler 112, and EGR valve 114.

[0095] The low-temperature cooling system of the intake intercooler includes: an electronic water pump 114, a low-temperature radiator 115, an electronically controlled three-way valve 116, and a motor MCU 117.

[0096] The ECU control system includes: ECU controller 119, ambient temperature sensor 100, EGR valve differential pressure sensor 113, motor MCU temperature sensor 118, intake intercooler temperature sensor 105, and intake manifold temperature sensor 107.

[0097] The exhaust gas recirculation (EGR) system control method for preventing engine stall provided in this application embodiment can be implemented by the vehicle controller, as shown in Figure 2, including steps S201, S202, S203, S204, S205, S206, S207, and S208, wherein:

[0098] In step S201, the actual ambient temperature is obtained.

[0099] In step S202, the theoretical temperature after intercooling corresponding to the actual ambient temperature is determined based on the first correspondence between the actual ambient temperature and the pre-stored ambient temperature and the theoretical temperature after intercooling.

[0100] In step S203, the cooling flow rate of the intercooler is adjusted according to the theoretical temperature after intercooling.

[0101] In step S204, the engine load and the actual temperature of the engine intake air after intercooling are obtained.

[0102] In step S205, the temperature difference between the theoretical temperature after intercooling and the actual temperature after intercooling is determined.

[0103] In step S206, the engine load and temperature difference are used as inputs to input the second correspondence between the pre-stored engine load, temperature difference and EGR correction coefficient, and the EGR correction coefficient corresponding to the engine load and temperature difference is determined.

[0104] In step S207, the theoretical EGR rate is corrected according to the EGR correction coefficient to obtain the target EGR rate.

[0105] In step S208, the EGR valve is controlled to achieve the target EGR rate.

[0106] Before obtaining the ambient temperature in step S201, a first correspondence between the ambient temperature and the theoretical temperature after intercooling can be pre-calibrated and stored. The step of calibrating and storing the first correspondence includes:

[0107] The initial values ​​of the ambient temperature and the temperature after cooling during the test are both set to the first preset temperature threshold.

[0108] The ambient temperature is increased by a first preset temperature step, and the temperature after cooling in the test is determined for each ambient temperature until the ambient temperature reaches the second preset temperature threshold.

[0109] Based on each test ambient temperature and the corresponding intermediate cooling temperature, a first correspondence between the ambient temperature and the theoretical temperature after intermediate cooling is obtained and stored.

[0110] Among them, the cooling temperatures corresponding to each test environment temperature are determined as follows:

[0111] Set the initial engine speed to the minimum preset speed and control the EGR valve to keep the EGR rate at its maximum.

[0112] The engine speed is increased according to the preset speed step size, and the intermediate temperature after cooling corresponding to each engine speed is determined until the engine speed reaches the maximum preset speed.

[0113] The maximum intermediate temperature after cooling in the test was determined from the intermediate temperatures after cooling corresponding to each engine speed.

[0114] Among them, determining the intermediate temperature after cooling corresponding to each engine speed in the test includes:

[0115] The temperature after cooling during the test is increased by the second preset temperature step until the engine does not misfire. The temperature after cooling during the test at this point is taken as the intermediate temperature after cooling during the test.

[0116] In some optional embodiments, as shown in Figure 3, the step of pre-calibrating the first correspondence between the ambient temperature and the theoretical temperature after intercooling can specifically include:

[0117] In step S301, the test environment temperature is set to a first preset temperature threshold, and the test environment humidity is set to 100%.

[0118] The first preset temperature threshold corresponds to the minimum acceptable ambient temperature.

[0119] In step S302, it is determined whether the ambient temperature of the test environment has reached the second preset temperature threshold.

[0120] The second preset temperature threshold corresponds to the maximum acceptable ambient temperature.

[0121] If the judgment result of step S302 is negative, proceed to step S303, in which the initial value of the engine speed is set to the minimum preset speed.

[0122] In step S304, it is determined whether the engine speed exceeds the maximum speed at which the EGR operates.

[0123] If the judgment result of step S304 is negative, proceed to step S305. In step S305, set the initial value of the temperature after cooling in the test to the first preset temperature threshold, and control the EGR valve to keep the EGR rate at its maximum.

[0124] In some alternative embodiments, in step S305, the temperature after intercooling is made equal to the ambient temperature, and the EGR valve is controlled to keep the EGR rate at its maximum.

[0125] In step S306, the temperature after cooling during the test is increased by a second preset temperature step, and the engine is controlled to run in steady state for 20 minutes. Then, the throttle opening is kept at maximum for 5 seconds.

[0126] In step S307, it is determined whether the engine has stalled. That is, whether the engine stalled in step S306.

[0127] If the judgment result of step S307 is yes, that is, the engine stalled in step S306, then return to step S306 again, increase the temperature after cooling in the test by the second preset temperature step again, control the engine to run in steady state for 20 minutes, and then keep the throttle opening at maximum for 5 seconds.

[0128] If the judgment result of step S307 is negative, that is, the engine did not stall in step S306, then proceed to step S308. In step S308, the temperature after cooling in the test at this time is taken as the intermediate temperature after cooling in the test corresponding to the current speed.

[0129] In step S309, the intermediate temperature after cooling in the test corresponding to the current rotation speed is compared with the intermediate temperature after cooling in the test corresponding to the previous rotation speed, and the maximum value is taken.

[0130] In step S310, the engine speed is increased by a preset speed step.

[0131] After step S310, return to step S304 to determine whether the engine speed exceeds the maximum operating speed of EGR. If it is determined that the engine speed exceeds the maximum operating speed of EGR, exit the loop of step S304-step S310 and proceed to step S311.

[0132] It is understandable that by using the cycle of steps S304-S310, the engine speed can be increased according to the preset speed step size, and the intermediate temperature after cooling in the test corresponding to each engine speed can be determined until the engine speed reaches the maximum preset speed.

[0133] By using the loop of steps S306-S307 nested within steps S304-S310, the temperature after cooling in the test can be increased by a second preset temperature step until the engine does not misfire. The temperature after cooling in the test at this point is taken as the intermediate temperature after cooling in the test.

[0134] After exiting the loop of steps S304-S310 and entering step S311, in step S311, the intermediate temperature after cooling in the experiment is taken as the theoretical temperature after cooling corresponding to the current experimental ambient temperature.

[0135] It is understandable that in step S311, after obtaining the theoretical temperature after intercooling, the theoretical temperature after intercooling and the ambient temperature can be stored accordingly to obtain a set of theoretical temperature after intercooling and ambient temperature.

[0136] In step S312, the ambient temperature is increased by a first preset temperature step. After step S312, the process returns to step S302 to determine whether the ambient temperature has reached a second preset temperature threshold.

[0137] It is understandable that the cycle S302-S312 can increase the test environment temperature by a first preset temperature step and determine the test cooling temperature corresponding to each test environment temperature until the test environment temperature reaches the second preset temperature threshold.

[0138] If the judgment result in step S302 is yes, that is, after the test environment temperature reaches the second preset temperature threshold, the loop S302-S312 is exited, and finally the first correspondence between the environment temperature and the theoretical temperature after cooling is obtained based on each test environment temperature and the corresponding test cooling temperature, and the first correspondence is stored.

[0139] The first correspondence can be shown in Table 1:

[0140] Table 1

[0141] In some optional embodiments, before obtaining the ambient temperature in step S201, a second correspondence between the temperature difference and the EGR correction coefficient can be pre-calibrated and stored. The step of calibrating and storing the second correspondence includes:

[0142] The initial value of the test temperature difference is set to the first preset temperature difference threshold, the engine speed is set to the ideal preset speed threshold corresponding to the maximum EGR rate, the engine load is set to the first preset load threshold, and the EGR rate is set to the ideal EGR rate corresponding to the engine load.

[0143] The test temperature difference is increased by a third preset temperature step, and an EGR correction coefficient is determined for each test temperature difference until the test temperature difference reaches the second preset temperature difference threshold.

[0144] Based on each test temperature difference, the EGR correction factor corresponding to each test temperature difference, and the engine load corresponding to the EGR correction factor, a second correspondence between engine load, temperature difference, and EGR correction factor is obtained and stored.

[0145] The EGR correction factors for each test temperature difference include:

[0146] The engine load is reduced by a preset load step size, and the EGR correction coefficient corresponding to each engine load is determined until the engine load reaches the preset load threshold.

[0147] The EGR correction factor for each engine load includes:

[0148] The EGR rate is reduced by a preset EGR rate step size until the engine does not misfire. The ratio between the experimental EGR rate and the ideal EGR rate at this point is determined as the EGR correction factor.

[0149] In some optional embodiments, as shown in Figure 4, the step of pre-calibrating and storing the second correspondence between the temperature difference and the EGR correction factor may specifically include:

[0150] In step S401, the ambient humidity of the test environment is set to 100%, and the engine speed is set to the ideal preset speed threshold corresponding to the maximum EGR rate.

[0151] In step S402, the initial value of the test temperature difference is set to the first preset temperature difference threshold.

[0152] In some alternative embodiments, the first preset temperature difference threshold may be an acceptable minimum temperature difference.

[0153] In step S403, the engine load is set to a first preset load threshold.

[0154] In some alternative embodiments, the first preset load threshold may be the maximum acceptable load.

[0155] In step S404, the EGR rate is set to the ideal EGR rate corresponding to the engine load.

[0156] In step S405, the EGR rate is reduced by a preset EGR rate step size, the engine runs stably for 20 minutes, and the engine is controlled to run in steady state for 20 minutes. Then, the throttle opening is kept at its maximum for 5 seconds.

[0157] In step S406, it is determined whether the engine has stalled. In other words, it is determined whether the engine stalled in step S405.

[0158] If the judgment result of step S406 is yes, that is, the engine has stalled, then return to step S405, reduce the EGR rate by the preset EGR rate step, the engine runs stably for 20 minutes, and the engine is controlled to run in steady state for 20 minutes. Then, keep the throttle opening at maximum for 5 seconds, and use step S406 again to determine whether the engine has stalled.

[0159] If the result of step S406 is negative, meaning the engine has not stalled, then proceed to step S407.

[0160] In step S407, the ratio between the experimental EGR rate and the ideal EGR rate at this time is determined as the EGR correction factor.

[0161] It is understandable that by using the cycle of steps S405-S406 plus step S407, the EGR rate can be reduced by a preset EGR rate step size until the engine does not misfire. The ratio between the test EGR rate and the ideal EGR rate at this time is determined as the EGR correction coefficient and stored.

[0162] In step S408, the engine load is reduced by a preset load step size.

[0163] In step S409, it is determined whether the engine load has reached the preset load threshold.

[0164] If the judgment result of step S406 is negative, that is, the engine load has not been reduced to the preset load threshold, then return to step S404.

[0165] By using the loop of steps S404-S409, the engine load can be reduced in preset load steps, and the EGR correction coefficient corresponding to each engine load can be determined until the engine load reaches a preset load threshold. The preset load threshold can be an acceptable minimum load.

[0166] In step S410, the test temperature difference is increased by a third preset temperature step.

[0167] In step S411, it is determined whether the test temperature difference is greater than the second preset temperature difference threshold.

[0168] If the judgment result of step S411 is negative, that is, the test temperature difference is not greater than the second preset temperature difference threshold, then return to step S403.

[0169] By using the loop of steps S403-S411, the test temperature difference can be increased by a third preset temperature step, and an EGR correction coefficient corresponding to each test temperature difference can be determined until the test temperature difference reaches a second preset temperature difference threshold. The second preset temperature difference threshold can be the maximum acceptable temperature difference.

[0170] If the judgment result of step S411 is yes, that is, the test temperature difference is greater than the second preset temperature difference threshold, then the calibration process of the second correspondence ends. Using the loop of steps S403-S411, a second correspondence between engine load, temperature difference, and EGR correction coefficient can be obtained based on each test temperature difference, the EGR correction coefficient corresponding to each test temperature difference, and the engine load corresponding to the EGR correction coefficient, and this second correspondence is stored. It can be understood that the second correspondence is a two-dimensional relationship, with the temperature difference and engine load as inputs and the EGR correction coefficient as the output.

[0171] Understandably, engine load can be represented by engine charging efficiency. Charging efficiency refers to the ratio of the actual mass of fresh air drawn into the cylinder to the theoretical mass of air filling the cylinder's working volume under intake manifold conditions during each working cycle of an internal combustion engine. It is an important parameter for evaluating the completeness of the actual scavenging process in an internal combustion engine. The higher the charging efficiency, the more air enters a given cylinder volume per cycle, resulting in greater power and torque, and better performance.

[0172] The second correspondence between engine load, temperature difference, and EGR correction factor can be shown in Table 2:

[0173] Table 2

[0174] In some optional embodiments, the effect of intake manifold temperature on engine shutdown can also be considered. After step S206, i.e., determining the EGR correction coefficient corresponding to the temperature difference, the method further includes:

[0175] The EGR correction factor corresponding to the temperature difference is used as the first EGR correction factor.

[0176] Obtain the intake manifold temperature.

[0177] Based on the pre-stored third correspondence between intake manifold temperature and EGR correction factor, determine the second EGR correction factor corresponding to the intake manifold temperature.

[0178] The minimum value between the first EGR correction factor and the second EGR correction factor is taken as the final EGR correction factor.

[0179] The theoretical EGR rate is corrected based on the final EGR correction factor to obtain the target EGR rate.

[0180] Control the EGR valve to achieve the target EGR rate.

[0181] In some optional embodiments, the effect of atmospheric pressure on engine shutdown can also be considered to adapt to high-altitude environments. After step S206, i.e., determining the EGR correction factor corresponding to the temperature difference, the method further includes:

[0182] The EGR correction factor corresponding to the temperature difference is used as the first EGR correction factor.

[0183] Obtain atmospheric pressure.

[0184] Based on the pre-stored fourth correspondence between atmospheric pressure and EGR correction factor, the third EGR correction factor corresponding to atmospheric pressure is determined.

[0185] The product of the first EGR correction factor and the third EGR correction factor is used as the final EGR correction factor.

[0186] The theoretical EGR rate is corrected based on the final EGR correction factor to obtain the target EGR rate.

[0187] Control the EGR valve to achieve the target EGR rate.

[0188] In some optional embodiments, the effects of intake manifold temperature and atmospheric pressure on engine shutdown can also be considered simultaneously, and the product of the minimum between the first EGR correction factor and the second EGR correction factor and the third EGR correction factor can be used as the final EGR correction factor.

[0189] The exhaust gas recirculation (EGR) system control method provided in this application, based on a pre-calibrated and stored first correspondence, determines and obtains the theoretical temperature after intercooling corresponding to the actual ambient temperature, and adjusts the cooling flow of the intercooler accordingly. This brings the actual temperature of the engine intake air after intercooling closer to the theoretical temperature. However, a temperature difference still exists between the theoretical and actual temperatures after intercooling. Furthermore, based on a pre-calibrated and stored second correspondence, an EGR correction coefficient corresponding to the temperature difference and engine load is determined. The EGR rate is then corrected using the EGR correction coefficient to obtain the target EGR rate. The EGR valve is controlled based on the target EGR rate to prevent engine stalling caused by condensed liquid water in the engine, thus ensuring stable engine operation.

[0190] This application embodiment also provides a control device for an exhaust gas recirculation (EGR) system to prevent engine shutdown. The device can be installed in the vehicle controller, as shown in Figure 5. The device includes:

[0191] The acquisition module 501 is configured to acquire the actual ambient temperature.

[0192] The determination module 502 is configured to determine the theoretical temperature after intercooling corresponding to the actual ambient temperature based on the first correspondence between the actual ambient temperature and the pre-stored ambient temperature and the theoretical temperature after intercooling.

[0193] The control module 503 is configured to adjust the cooling flow rate of the intercooler according to the theoretical temperature after intercooling.

[0194] The acquisition module 501 is also configured to acquire the engine load and the actual temperature of the engine intake air after intercooling.

[0195] The determination module 502 is also configured to determine the temperature difference between the theoretical temperature after intercooling and the actual temperature after intercooling.

[0196] The determination module 502 is also configured to take the engine load and temperature difference as inputs and input a pre-stored second correspondence between the engine load, temperature difference and EGR correction coefficient to determine the EGR correction coefficient corresponding to the engine load and temperature difference.

[0197] The determination module 502 is also configured to correct the theoretical EGR rate based on the EGR correction factor to obtain the target EGR rate.

[0198] Control module 503 is also configured to control the EGR valve to achieve the target EGR rate.

[0199] Alternatively, the device may also include:

[0200] The setting module 504 is configured to set the initial values ​​of both the test ambient temperature and the temperature after cooling during the test to a first preset temperature threshold.

[0201] The determination module 502 is also configured to increase the test environment temperature by a first preset temperature step and determine the test cooling temperature corresponding to each test environment temperature, until the test environment temperature reaches a second preset temperature threshold.

[0202] The determining module 502 is also configured to obtain a first correspondence between the ambient temperature and the theoretical temperature after cooling based on each test ambient temperature and the test cooling temperature corresponding to each test ambient temperature, and to store the first correspondence.

[0203] The setting module 504 is also configured to set the initial value of the engine speed to the minimum preset speed and control the EGR valve to keep the EGR rate at its maximum.

[0204] The determination module 502 is also configured to increase the engine speed by a preset speed step and determine the intermediate temperature after cooling for each engine speed until the engine speed reaches the maximum preset speed.

[0205] The determination module 502 is also configured to determine the maximum test intermediate temperature after cooling from the test intermediate temperatures corresponding to each engine speed.

[0206] The determination module 502 is also configured to increase the temperature after cooling in the test by a second preset temperature step until the engine does not misfire, and take the temperature after cooling in the test at this time as the intermediate temperature after cooling in the test.

[0207] The setting module 504 is also configured to set the initial value of the test temperature difference to a first preset temperature difference threshold, set the engine speed to an ideal preset speed threshold corresponding to the maximum EGR rate, set the engine load to a first preset load threshold, and set the EGR rate to an ideal EGR rate corresponding to the engine load.

[0208] The determination module 502 is also configured to increase the test temperature difference by a third preset temperature step and determine the EGR correction coefficient corresponding to each test temperature difference until the test temperature difference reaches the second preset temperature difference threshold.

[0209] The determining module 502 is further configured to obtain a second correspondence between engine load, temperature difference and EGR correction coefficient based on each test temperature difference, the EGR correction coefficient corresponding to each test temperature difference, and the engine load corresponding to the EGR correction coefficient, and store the second correspondence.

[0210] The determination module 502 is also configured to reduce the engine load by a preset load step size and determine the EGR correction coefficient corresponding to each engine load until the engine load reaches a preset load threshold.

[0211] The determination module 502 is also configured to decrease the EGR rate by a preset EGR rate step size until the engine does not misfire, and the ratio between the test EGR rate and the ideal EGR rate at this time is determined as the EGR correction factor.

[0212] Alternatively, the determining module 502 is further configured to use the EGR correction factor corresponding to the temperature difference as the first EGR correction factor after determining the EGR correction factor corresponding to the temperature difference.

[0213] The acquisition module 501 is also configured to acquire the intake manifold temperature.

[0214] The determining module 502 is also configured to determine a second EGR correction factor corresponding to the intake manifold temperature based on a third correspondence between the pre-stored intake manifold temperature and the EGR correction factor.

[0215] The determining module 502 is also configured to use the minimum value between the first EGR correction factor and the second EGR correction factor as the final EGR correction factor.

[0216] The determination module 502 is also configured to correct the theoretical EGR rate based on the final EGR correction factor to obtain the target EGR rate.

[0217] Control module 503 is also configured to control the EGR valve to achieve the target EGR rate.

[0218] Alternatively, after determining the EGR correction factor corresponding to the temperature difference, the determining module 502 is further configured to use the EGR correction factor corresponding to the temperature difference as the first EGR correction factor.

[0219] The acquisition module 501 is also configured to acquire atmospheric pressure.

[0220] The determination module 502 is also configured to determine a third EGR correction factor corresponding to atmospheric pressure based on a pre-stored fourth correspondence between atmospheric pressure and EGR correction factor.

[0221] The determining module 502 is also configured to use the product between the first EGR correction factor and the third EGR correction factor as the final EGR correction factor.

[0222] The determination module 502 is also configured to correct the theoretical EGR rate based on the final EGR correction factor to obtain the target EGR rate.

[0223] Control module 503 is also configured to control the EGR valve to achieve the target EGR rate.

[0224] The exhaust gas recirculation (EGR) system control device provided in this application, based on a pre-calibrated and stored first correspondence, determines and obtains the theoretical temperature after intercooling corresponding to the actual ambient temperature, and adjusts the cooling flow of the intercooler accordingly. This brings the actual temperature of the engine intake air after intercooling closer to the theoretical temperature. However, a temperature difference still exists between the theoretical and actual temperatures after intercooling. Furthermore, based on a pre-calibrated and stored second correspondence, an EGR correction coefficient corresponding to the temperature difference and engine load is determined. The EGR rate is then corrected using the EGR correction coefficient to obtain the target EGR rate. The EGR valve is controlled based on the target EGR rate to prevent engine stalling caused by condensed liquid water in the engine, thus ensuring stable engine operation.

[0225] This application also provides an electronic device, which can vary considerably depending on its configuration or performance. It may include one or more Central Processing Units (CPUs) and one or more memories, wherein the memory stores at least one instruction, which is loaded and executed by the processor to implement the methods provided in the above-described method embodiments. Of course, the server may also have wired or wireless network interfaces, a keyboard, and input / output interfaces for input and output. The server may also include other components for implementing device functions, which will not be elaborated upon here.

[0226] In an exemplary embodiment, a computer-readable storage medium is also provided, applied to an electronic device, such as a memory including instructions that can be executed by a processor to perform the methods in the above embodiments. For example, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage device, etc.

[0227] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0228] In this application, it should be understood that the terms “first”, “second”, etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0229] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0230] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

[0231] The above is merely for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims

1. A control method for an EGR system to prevent flameout, characterized in that, The method includes: Obtain the actual ambient temperature; Based on the first correspondence between the actual ambient temperature and the pre-stored ambient temperature and theoretical temperature after intercooling, the theoretical temperature after intercooling corresponding to the actual ambient temperature is determined. Adjust the cooling flow rate of the intercooler according to the theoretical temperature after intercooling; Obtain the engine load and the actual temperature of the engine intake air after intercooling through the intercooler; Determine the temperature difference between the theoretical temperature after intercooling and the actual temperature after intercooling; The engine load and the temperature difference are used as inputs to input the second correspondence between the pre-stored engine load, the temperature difference and the EGR correction coefficient, and the EGR correction coefficient corresponding to the engine load and the temperature difference is determined. The theoretical EGR rate is corrected based on the EGR correction coefficient to obtain the target EGR rate; Control the EGR valve to achieve the target EGR rate.

2. The control method for the anti-flameout exhaust gas recirculation (EGR) system according to claim 1, characterized in that, Prior to obtaining the ambient temperature, the method further includes: The initial values ​​of the test environment temperature and the temperature after cooling during the test are both set to the first preset temperature threshold. The test environment temperature is increased by a first preset temperature step, and the temperature after cooling during the test is determined for each test environment temperature, until the test environment temperature reaches a second preset temperature threshold. Based on each of the test ambient temperatures and the corresponding intermediate cooling temperatures, a first correspondence between the ambient temperatures and the theoretical intermediate cooling temperatures is obtained and stored. Wherein, determining the cooling temperature corresponding to each of the test environment temperatures includes: Set the initial engine speed to the minimum preset speed and control the EGR valve to keep the EGR rate at its maximum. The engine speed is increased according to a preset speed step size, and the intermediate temperature after cooling in the test corresponding to each engine speed is determined until the engine speed reaches the maximum preset speed. The maximum intermediate temperature after cooling during the test is determined from the intermediate temperatures after cooling corresponding to each of the engine speeds. The determination of the intermediate temperature after cooling corresponding to each engine speed includes: The temperature after cooling in the test is increased by a second preset temperature step until the engine does not misfire. The temperature after cooling in the test at this point is taken as the intermediate temperature after cooling in the test.

3. The control method for the anti-flameout exhaust gas recirculation (EGR) system according to claim 1, characterized in that, Before obtaining the actual ambient temperature, the method further includes: The initial value of the test temperature difference is set to the first preset temperature difference threshold, the engine speed is set to the ideal preset speed threshold corresponding to the maximum EGR rate, the engine load is set to the first preset load threshold, and the EGR rate is set to the ideal EGR rate corresponding to the engine load. The test temperature difference is increased by a third preset temperature step, and the EGR correction coefficient corresponding to each test temperature difference is determined until the test temperature difference reaches a second preset temperature difference threshold. Based on each of the test temperature differences, the EGR correction coefficient corresponding to each of the test temperature differences, and the engine load corresponding to the EGR correction coefficient, a second correspondence between the engine load, the temperature difference, and the EGR correction coefficient is obtained and stored. Wherein, the determination of the EGR correction factor corresponding to each of the test temperature differences includes: The engine load is reduced in preset load increments, and an EGR correction coefficient corresponding to each engine load is determined, until the engine load reaches a preset load threshold. The determination of the EGR correction coefficient corresponding to each engine load includes: The EGR rate is reduced by a preset EGR rate step size until the engine does not misfire. The ratio between the experimental EGR rate and the ideal EGR rate at this point is determined as the EGR correction coefficient.

4. The control method for the anti-flameout exhaust gas recirculation (EGR) system according to claim 1, characterized in that, After determining the EGR correction coefficient corresponding to the temperature difference, the method further includes: The EGR correction factor corresponding to the temperature difference is used as the first EGR correction factor; Obtain the intake manifold temperature; Based on the pre-stored third correspondence between intake manifold temperature and EGR correction coefficient, determine the second EGR correction coefficient corresponding to the intake manifold temperature; The minimum value between the first EGR correction factor and the second EGR correction factor is taken as the final EGR correction factor; The theoretical EGR rate is corrected based on the final EGR correction coefficient to obtain the target EGR rate; Control the EGR valve to achieve the target EGR rate.

5. The control method for the anti-flameout exhaust gas recirculation (EGR) system according to claim 1, characterized in that, After determining the EGR correction coefficient corresponding to the temperature difference, the method further includes: The EGR correction factor corresponding to the temperature difference is used as the first EGR correction factor; Obtain atmospheric pressure; Based on the pre-stored fourth correspondence between atmospheric pressure and EGR correction coefficient, determine the third EGR correction coefficient corresponding to the atmospheric pressure; The product of the first EGR correction factor and the third EGR correction factor is taken as the final EGR correction factor; The theoretical EGR rate is corrected based on the final EGR correction coefficient to obtain the target EGR rate; Control the EGR valve to achieve the target EGR rate.

6. A control device for an EGR system to prevent flameout, characterized in that, The device includes: The acquisition module is configured to acquire the actual ambient temperature. The determination module is configured to determine the theoretical temperature after intercooling corresponding to the actual ambient temperature based on the first correspondence between the actual ambient temperature and a pre-stored relationship between the ambient temperature and the theoretical temperature after intercooling. The control module is configured to adjust the cooling flow rate of the intercooler according to the theoretical temperature after intercooling; The acquisition module is also configured to acquire the engine load and the actual temperature of the engine intake air after intercooling by the intercooler. The determining module is also configured to determine the temperature difference between the theoretical temperature after intercooling and the actual temperature after intercooling. The determining module is further configured to take the engine load and the temperature difference as inputs and input a pre-stored second correspondence between the engine load, the temperature difference and the EGR correction coefficient to determine the EGR correction coefficient corresponding to the engine load and the temperature difference; The determining module is further configured to correct the theoretical EGR rate according to the EGR correction coefficient to obtain the target EGR rate; The control module is also configured to control the EGR valve to achieve the target EGR rate.

7. The control device for the anti-flameout exhaust gas recirculation (EGR) system according to claim 6, characterized in that, The device further includes: The setting module is configured to set the initial values ​​of both the test environment temperature and the temperature after cooling during the test to the first preset temperature threshold. The determining module is further configured to increase the test environment temperature by a first preset temperature step, and determine the test cooling temperature corresponding to each of the test environment temperatures, until the test environment temperature reaches a second preset temperature threshold. The determining module is further configured to obtain the first correspondence between the ambient temperature and the theoretical temperature after cooling based on each of the test ambient temperatures and the corresponding intermediate cooling temperature for each of the test ambient temperatures, and to store the first correspondence. The setting module is also configured to set the initial value of the engine speed to the minimum preset speed and control the EGR valve to keep the EGR rate at its maximum. The determining module is also configured to increase the engine speed by a preset speed step size, and determine the intermediate temperature after cooling in the test corresponding to each engine speed, until the engine speed reaches the maximum preset speed. The determining module is further configured to determine the maximum intermediate temperature after cooling in the test from the intermediate temperatures after cooling in the test corresponding to each of the engine speeds. The determining module is further configured to increase the temperature after cooling in the test by a second preset temperature step until the engine does not misfire, and take the temperature after cooling in the test at this time as the intermediate temperature after cooling in the test.

8. The control device for the anti-flameout exhaust gas recirculation (EGR) system according to claim 6, characterized in that, The device further includes: The setting module is configured to set the initial value of the test temperature difference to a first preset temperature difference threshold, set the engine speed to an ideal preset speed threshold corresponding to the maximum EGR rate, set the engine load to a first preset load threshold, and set the EGR rate to an ideal EGR rate corresponding to the engine load. The determining module is further configured to increase the test temperature difference by a third preset temperature step, and determine the EGR correction coefficient corresponding to each of the test temperature differences, until the test temperature difference reaches a second preset temperature difference threshold. The determining module is further configured to obtain a second correspondence between the engine load, the temperature difference, and the EGR correction coefficient based on each of the test temperature differences, the EGR correction coefficient corresponding to each of the test temperature differences, and the engine load corresponding to the EGR correction coefficient, and to store the second correspondence. The determining module is further configured to reduce the engine load by a preset load step size and determine the EGR correction coefficient corresponding to each engine load until the engine load reaches a preset load threshold. The determining module is further configured to decrease the EGR rate by a preset EGR rate step size until the engine does not misfire, and to determine the ratio between the test EGR rate and the ideal EGR rate at this time as the EGR correction coefficient.

9. The control device for the anti-flameout exhaust gas recirculation (EGR) system according to claim 6, characterized in that, The determining module is further configured to, after determining the EGR correction coefficient corresponding to the temperature difference, use the EGR correction coefficient corresponding to the temperature difference as the first EGR correction coefficient; The acquisition module is further configured to acquire the intake manifold temperature; The determining module is further configured to determine a second EGR correction coefficient corresponding to the intake manifold temperature based on a third correspondence between the pre-stored intake manifold temperature and the EGR correction coefficient. The determining module is further configured to use the minimum value between the first EGR correction coefficient and the second EGR correction coefficient as the final EGR correction coefficient; The determining module is further configured to correct the theoretical EGR rate based on the final EGR correction coefficient to obtain the target EGR rate; The control module is also configured to control the EGR valve to achieve the target EGR rate.

10. The control device for the anti-flameout exhaust gas recirculation (EGR) system according to claim 6, characterized in that, After determining the EGR correction coefficient corresponding to the temperature difference, the determining module is further configured to use the EGR correction coefficient corresponding to the temperature difference as the first EGR correction coefficient. The acquisition module is also configured to acquire atmospheric pressure; The determining module is further configured to determine a third EGR correction factor corresponding to the atmospheric pressure based on a pre-stored fourth correspondence between atmospheric pressure and EGR correction factor; The determining module is further configured to use the product between the first EGR correction coefficient and the third EGR correction coefficient as the final EGR correction coefficient; The determining module is further configured to correct the theoretical EGR rate based on the final EGR correction coefficient to obtain the target EGR rate; The control module is also configured to control the EGR valve to achieve the target EGR rate.

11. An electronic device, characterized in that, The electronic device includes one or more processors and one or more memories, wherein at least one instruction is stored in the one or more memories, the instruction being loaded and executed by the one or more processors to perform the operation performed by the anti-flameout exhaust gas recirculation (EGR) system control method as described in any one of claims 1 to 5.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which is loaded and executed by a processor to perform the operation of the anti-flameout exhaust gas recirculation (EGR) system control method as described in any one of claims 1 to 5.

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