Post-processing method and apparatus, vehicle, and storage medium

Abstract

This application relates to the field of vehicle technology and discloses an after-treatment method, apparatus, computer equipment, and storage medium. The method includes: when switching from controlling the engine of a vehicle to operating in a lean-burn mode to controlling the engine to operate in a rich-burn mode, obtaining a target rich-burn air-fuel ratio, wherein the target rich-burn air-fuel ratio is pre-calibrated; controlling the engine to operate in the rich-burn mode at the target rich-burn air-fuel ratio for a first rich-burn running time, including: controlling the air-fuel ratio of the engine to the target rich-burn air-fuel ratio.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to post-processing methods, apparatus, vehicles, and storage media. Background Technology

[0002] Currently, vehicles equipped with lean NOx trap (LNT) engines must intermittently employ a rich-fuel cycle to regenerate the LNT (desorb adsorbed NOx) and convert the released NOx into nitrogen (N2). Vehicles operating in rich-fuel mode have higher fuel consumption. Furthermore, as normal operation, LNT desulfurization and gasoline particulate filter (GPF) regeneration are performed at temperatures significantly higher than the catalyst (LNT, GPF, etc.) temperatures during normal vehicle operation. This increased aftertreatment system temperature further increases fuel consumption. Therefore, reducing the number of rich-fuel regeneration cycles while ensuring NOx conversion efficiency, and simultaneously reducing fuel consumption while ensuring the normal and efficient operation of the LNT system, has become a problem that needs to be solved. Summary of the Invention

[0003] In view of this, embodiments of this application provide a post-processing method, apparatus, vehicle, and storage medium.

[0004] In a first aspect, embodiments of this application provide an aftertreatment method applied to a vehicle, the vehicle being equipped with a lean nitrogen oxide capture catalyst (LNT), the method comprising:

[0005] When switching from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode, a target rich-burn air-fuel ratio is obtained, wherein the target rich-burn air-fuel ratio is pre-calibrated;

[0006] Controlling the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration includes: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

[0007] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by satisfying a first condition, the first condition including: the weight of nitrogen oxides adsorbed on LNTs during a target sub-period while controlling the engine to operate in lean-burn mode is greater than a nitrogen oxide adsorption weight threshold.

[0008] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by determining that a second condition is met during the period when the engine is operating in lean-burn mode. The second condition includes: the first average nitrogen oxide adsorption rate of LNTs determined during the period when the engine is controlled to operate in lean-burn mode is less than a first nitrogen oxide adsorption rate threshold.

[0009] In one possible implementation, the method also includes:

[0010] After controlling the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation period, the second average nitrogen oxide adsorption rate of LNT is determined.

[0011] When the average adsorption rate of the second nitrogen oxide is less than the adsorption rate threshold of the second nitrogen oxide, a first desulfurization operation is performed. The first desulfurization operation includes: controlling the temperature of the LNT to a temperature within a first desulfurization temperature range, and when the temperature of the LNT is within the first desulfurization temperature range, controlling the engine to run in lean-burn mode with a target lean-burn air-fuel ratio for a first lean-burn running time.

[0012] In one possible implementation, the method also includes:

[0013] After the first desulfurization operation is completed, the average adsorption rate of nitrogen oxides of LNT is determined.

[0014] When the average adsorption rate of the third nitrogen oxide is less than the adsorption rate threshold of the third nitrogen oxide, a second desulfurization operation is performed. The second desulfurization operation includes: controlling the temperature of the LNT to a temperature within the second desulfurization temperature range, and when the temperature of the LNT is within the second desulfurization temperature range, controlling the engine to operate in lean-burn mode for a second lean-burn duration, and controlling the engine to operate in rich-burn mode for a second rich-burn duration, wherein the second rich-burn duration is greater than the second lean-burn duration, and the ratio of the second lean-burn duration to the second rich-burn duration is a preset ratio.

[0015] In one possible implementation, the method also includes:

[0016] After the second desulfurization operation is completed, the average adsorption rate of the fourth nitrogen oxides of LNT is determined. If the average adsorption rate of the fourth nitrogen oxides is less than the threshold value of the fourth nitrogen oxides adsorption rate, the second desulfurization operation is performed again. After the second desulfurization operation is completed, the average adsorption rate of the fifth nitrogen oxides of LNT is determined. If the average adsorption rate of the fifth nitrogen oxides is less than the threshold value of the fifth nitrogen oxides adsorption rate, it indicates that the desulfurization has failed and the LNT catalyst is at risk of failure, and an alarm is triggered.

[0017] In one possible implementation, the vehicle is equipped with a particulate filter (GPF) and also includes:

[0018] After the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT, the first exhaust back pressure of the GPF is obtained, and in response to the first exhaust back pressure being greater than the exhaust back pressure lower limit threshold, a first GPF active regeneration operation is performed. The first GPF active regeneration operation includes: controlling the temperature of the GPF within the GPF active regeneration temperature range, and controlling the engine to operate at a target lean-burn air-fuel ratio for a first active regeneration duration, wherein the magnitude of the first active regeneration duration is positively correlated with the magnitude of the GPF back pressure; and determining the fourth average nitrogen oxide adsorption rate of the LNT includes:

[0019] In response to the completion of the first GPF active regeneration operation, the average adsorption rate of the fourth nitrogen oxides of the LNT is determined. When the average adsorption rate of the fourth nitrogen oxides is less than the fourth nitrogen oxide adsorption rate threshold, the second desulfurization operation is performed again. After the second desulfurization operation is completed, the average adsorption rate of the fifth nitrogen oxides of the LNT is determined. When the average adsorption rate of the fifth nitrogen oxides is less than the fifth nitrogen oxide adsorption rate threshold, it indicates that the desulfurization has failed, the LNT catalyst is at risk of failure, and an alarm is issued.

[0020] In one possible implementation, the vehicle is equipped with a particulate filter (GPF) and also includes:

[0021] After the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT, the first exhaust back pressure of the GPF is obtained; and determining the fourth average nitrogen oxide adsorption rate of the LNT includes:

[0022] In response to the first exhaust back pressure not exceeding the lower limit threshold of exhaust back pressure, the fourth average adsorption rate of nitrogen oxides (NOx) of the LNT is determined. When the fourth average adsorption rate of NOx is less than the fourth NOx adsorption rate threshold, the second desulfurization operation is performed again. After the second desulfurization operation is completed, the fifth average adsorption rate of NOx is determined. When the fifth average adsorption rate of NOx is less than the fifth NOx adsorption rate threshold, it indicates that desulfurization has failed, the LNT catalyst is at risk of failure, and an alarm is triggered.

[0023] In one possible implementation, the method further includes: obtaining the fuel consumption of the vehicle, and determining the sulfur content corresponding to the fuel consumption; determining whether the cumulative sulfur content on LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount;

[0024] When it is determined that the cumulative amount of LNT sulfur corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount, the second desulfurization operation is performed;

[0025] After the second desulfurization operation is completed, when a particulate filter (GPF) is installed on the vehicle, the second exhaust back pressure of the GPF is obtained; when the second exhaust back pressure is greater than the lower limit threshold of the exhaust back pressure, the first GPF active regeneration operation is performed. The first GPF active regeneration operation includes: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to run at a target lean air-fuel ratio for a first active regeneration duration.

[0026] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the method further includes: acquiring the third exhaust back pressure of the GPF; when the third exhaust back pressure is greater than an upper limit threshold for exhaust back pressure, performing a second GPF active regeneration operation, the second GPF active regeneration operation including: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to operate at a target lean air-fuel ratio for a second active regeneration duration; after the second GPF active regeneration operation is completed, acquiring the fuel consumption of the vehicle after the most recent second desulfurization, and determining the sulfur content corresponding to the fuel consumption; determining whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than a lower limit threshold for cumulative sulfur content; when it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold for cumulative sulfur content, performing a second desulfurization operation.

[0027] In one possible implementation, the method also includes:

[0028] When a shutdown command is received for the engine and the conditions for supplemental rich fuel are met, the engine is controlled to run in rich fuel mode with the target rich fuel air-fuel ratio for a first rich fuel running time. After the execution of controlling the engine to run in rich fuel mode with the target rich fuel air-fuel ratio for the first rich fuel running time is completed, the engine is controlled to shut down.

[0029] Secondly, embodiments of this application provide an aftertreatment device installed on a vehicle, the vehicle being equipped with a lean nitrogen oxide capture catalyst (LNT). The aftertreatment device includes:

[0030] A target rich air-fuel ratio acquisition unit is used to acquire a target rich air-fuel ratio when switching from controlling the engine of the vehicle to controlling the engine to run in a rich air-fuel mode, wherein the target rich air-fuel ratio is pre-calibrated.

[0031] A control unit is used to control the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration, including: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

[0032] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by satisfying a first condition, the first condition including: the weight of nitrogen oxides adsorbed on LNTs during a target sub-period while controlling the engine to operate in lean-burn mode is greater than a nitrogen oxide adsorption weight threshold.

[0033] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by determining that a second condition is met during the period when the engine is operating in lean-burn mode. The second condition includes: the first average nitrogen oxide adsorption rate of LNTs determined during the period when the engine is controlled to operate in lean-burn mode is less than a first nitrogen oxide adsorption rate threshold.

[0034] In one possible implementation, the post-processing device further includes:

[0035] A first processing unit is configured to determine a second average nitrogen oxide adsorption rate of the LNT after controlling the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration; and to perform a first desulfurization operation when the second average nitrogen oxide adsorption rate is less than a second nitrogen oxide adsorption rate threshold. The first desulfurization operation includes controlling the temperature of the LNT to a temperature within a first desulfurization temperature range, and controlling the engine to operate in a lean-fuel mode at the target lean-fuel ratio for a first lean-fuel operation duration when the temperature of the LNT is within the first desulfurization temperature range.

[0036] In one possible implementation, the post-processing device further includes:

[0037] The second processing unit is used to determine the average adsorption rate of the third nitrogen oxides of the LNT after the first desulfurization operation is completed; when the average adsorption rate of the third nitrogen oxides is less than the third nitrogen oxide adsorption rate threshold, a second desulfurization operation is performed. The second desulfurization operation includes: controlling the temperature of the LNT to a temperature within the second desulfurization temperature range, and when the temperature of the LNT is within the second desulfurization temperature range, controlling the engine to operate in lean-burn mode for a second lean-burn duration, and controlling the engine to operate in rich-burn mode for a second rich-burn duration, wherein the second rich-burn duration is greater than the second lean-burn duration, and the ratio of the second lean-burn duration to the second rich-burn duration is a preset ratio.

[0038] In one possible implementation, the post-processing device further includes:

[0039] The third processing unit is used to determine the fourth average adsorption rate of nitrogen oxides of LNT after the second desulfurization operation is completed; when the fourth average adsorption rate of nitrogen oxides is less than the fourth nitrogen oxide adsorption rate threshold, the second desulfurization operation is performed again; after the second desulfurization operation is performed again, the fifth average adsorption rate of nitrogen oxides of LNT is determined; when the fifth average adsorption rate of nitrogen oxides is less than the fifth nitrogen oxide adsorption rate threshold, LNT may fail and an alarm is triggered.

[0040] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes: a fourth processing unit configured to, after the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT, acquire a first exhaust back pressure of the GPF, and, in response to the first exhaust back pressure being greater than a lower exhaust back pressure threshold, perform a first GPF active regeneration operation, the first GPF active regeneration operation including: controlling the temperature of the GPF within a GPF active regeneration temperature range, and controlling the engine to operate at a target lean air-fuel ratio for a first active regeneration duration, wherein the magnitude of the first active regeneration duration is positively correlated with the magnitude of the GPF back pressure; and a third processing unit further configured to, in response to the completion of the first GPF active regeneration operation, determine the fourth average nitrogen oxide adsorption rate of the LNT.

[0041] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes: a fifth processing unit for acquiring a first exhaust back pressure of the GPF after the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT; and a third processing unit for determining the fourth average nitrogen oxide adsorption rate of the LNT in response to the first exhaust back pressure not being greater than an exhaust back pressure lower limit threshold.

[0042] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes:

[0043] The sixth processing unit is used to acquire the fuel consumption of the vehicle and determine the sulfur content corresponding to the fuel consumption; determine whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount; when it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount, perform a second desulfurization operation; after the second desulfurization operation is completed, acquire the second exhaust back pressure of the GPF; when the second exhaust back pressure is greater than the lower limit threshold of the exhaust back pressure, perform a first GPF active regeneration operation, the first GPF active regeneration operation including: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to run at a target lean air-fuel ratio for a first active regeneration duration.

[0044] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes:

[0045] The seventh processing unit is used to acquire the third exhaust back pressure of the GPF; when the third exhaust back pressure is greater than the upper limit threshold of the exhaust back pressure, a second GPF active regeneration operation is executed, the second GPF active regeneration operation includes: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to run the second active regeneration for a target lean air-fuel ratio for a specified duration; after the second GPF active regeneration operation is completed, the fuel consumption of the vehicle after the most recent second desulfurization operation is acquired, and the sulfur content corresponding to the fuel consumption is determined; whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold of the cumulative amount is determined; when it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold of the cumulative amount, the second desulfurization operation is executed.

[0046] In one possible implementation, the post-processing device further includes:

[0047] The eighth processing unit is configured to, when receiving a shutdown command for the engine and meeting the supplementary rich-fuel conditions, control the engine to run in rich-fuel mode at the target rich-fuel air-fuel ratio for a first rich-fuel running time, and after completing the execution of controlling the engine to run in rich-fuel mode at the target rich-fuel air-fuel ratio for the first rich-fuel running time, control the engine to shut down.

[0048] Thirdly, embodiments of this application provide a vehicle, including: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the method described in the first aspect or any corresponding embodiment.

[0049] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer instructions for causing a computer to perform the method described in the first aspect or any corresponding embodiment.

[0050] Fifthly, the present invention provides a computer program product, including computer instructions for causing a computer to perform the method described in the first aspect or any corresponding embodiment thereof.

[0051] The post-treatment method provided in this application embodiment achieves a target rich-fuel air-fuel ratio by calibration aimed at lower fuel consumption and higher rich-fuel regeneration power in rich-fuel mode. This target rich-fuel air-fuel ratio ensures lower fuel consumption when controlling the vehicle's engine to operate in rich-fuel mode. It also prevents the engine's air-fuel ratio from becoming excessively rich or lean. Excessive richness increases fuel consumption and emissions of pollutants such as HC, CO, and NH3. Excessive leanness increases the number of rich-fuel regeneration cycles. The target rich-fuel air-fuel ratio results in better rich-fuel regeneration performance, higher rich-fuel regeneration efficiency, and fewer rich-fuel regeneration cycles. Avoiding frequent rich-fuel regeneration reduces the number of de-NOx removal cycles and the number of separate de-SOx removal and GPF regeneration temperature increases, thereby reducing fuel consumption. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the structure of a post-processing system that can be used to execute the post-processing method provided in the embodiments of this application;

[0054] Figure 2 This is a structural schematic diagram of a vehicle provided in an embodiment of this application;

[0055] Figure 3 This is a schematic flowchart of the post-processing method provided in the embodiments of this application;

[0056] Figure 4 This is a flowchart illustrating an example of how a vehicle's engine operates;

[0057] Figure 5 This is an example of the process for switching from controlling the engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode;

[0058] Figure 6 This is a schematic diagram illustrating an example of closed-loop control of the air-fuel ratio in an engine;

[0059] Figure 7 This is a flowchart illustrating an example of post-processing using LNT and GPF;

[0060] Figure 8This is a flowchart illustrating another example of post-processing using LNT and GPF;

[0061] Figure 9 This is a schematic diagram of the structure of a computer device on a vehicle for executing the post-processing method provided in this application, as provided in an embodiment of this application. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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.

[0063] refer to Figure 1 It shows a schematic diagram of the structure of a post-processing system that can be used to perform the post-processing methods provided in the embodiments of this application.

[0064] The GPF differential pressure sensor measures the exhaust back pressure of the particulate filter (GPF). Exhaust temperature sensor 1 measures the temperature of the LNT (Low Temperature Tolerant). Exhaust temperature sensor 2 measures the temperature of the GPF. Nitrogen oxide sensor 1 measures the concentration of nitrogen oxides in the exhaust gas before it enters the LNT, and nitrogen oxide sensor 2 measures the concentration of nitrogen oxides in the exhaust gas after LNT treatment.

[0065] The working principle of the catalyst in lean-burn NOx capture (LNT) can be summarized as follows: A nitrogen oxide adsorbent is incorporated into the catalyst coating. During engine operation in lean-burn mode, in a lean-burn atmosphere, nitrogen oxides (NOx) in the engine exhaust are adsorbed by the adsorbent through chemical or physical means; the NOx is not converted. As an example, the adsorbent on the catalyst coating in an LNT primarily uses metal oxide adsorbents. Alkali metals (such as BaO) in the LNT catalyst coating adsorb NOx (including NO2 generated from the oxidation of NO) in the exhaust, forming nitrates (such as barium nitrate or barium nitrite). As another example, NOx (NO and NO2) is adsorbed onto ion-exchanged noble metal oxides on the catalyst coating in the LNT. The adsorbent on the catalyst coating in the LNT primarily uses noble metals combined with molecular sieves. During the operation of the engine in the fuel-rich mode, in the fuel-rich atmosphere, the adsorbed nitrogen oxides (through physical or chemical decomposition) are desorbed from the adsorbent, i.e., the adsorbent is regenerated, and the released nitrogen oxides are reduced to nitrogen gas on the catalyst in the LNT.

[0066] It should be noted that, Figure 1The structure of the aftertreatment system shown is only an example, and other structures can be used to implement the aftertreatment methods provided in the embodiments of this application. As an example, the nitrogen oxide sensor 1 with the air-fuel ratio λ signal can be replaced with the linear margin pre-oxygen sensor, i.e., the two can be combined into one, and the oxidizing catalyst GOC can also be integrated with the particulate filter GPF, i.e., GPF / GOC.

[0067] refer to Figure 2 This illustrates a structural schematic diagram of a vehicle provided in an embodiment of this application.

[0068] The vehicle includes: a hybrid power control unit (HCU), an engine control module (ECM), a motor control unit (MCU) for controlling the vehicle's drive motor, a generator control unit (GCU) for controlling the vehicle, the vehicle's drive motor (EM), and the vehicle's generator.

[0069] refer to Figure 3 The diagram illustrates a flowchart of the post-processing method provided in the embodiments of this application.

[0070] In step S301, when switching from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode, the target rich-burn air-fuel ratio is obtained.

[0071] The target rich air-fuel ratio is pre-calibrated and is used to reduce the fuel consumption of the engine when it is running in rich air-fuel mode.

[0072] It should be noted that during periods without desulfurization or GPF active regeneration, the engine can be controlled to alternately operate for a first lean-burn duration under conventional lean-burn conditions in lean-burn mode with a target lean-burn air-fuel ratio λL, and for a first rich-burn duration under conventional rich-burn conditions in rich-burn mode with a target rich-burn air-fuel ratio λR. Conventional lean-burn conditions are those satisfied during normal lean-burn operation. Conventional rich-burn conditions are those satisfied during normal rich-burn operation.

[0073] refer to Figure 4 It shows a flowchart illustrating an example of how a vehicle's engine operates.

[0074] In this example, after the vehicle's engine starts, it is alternately controlled to operate in lean-burn mode and rich-burn mode. When an engine shutdown signal is received, the vehicle's engine is controlled to stop operating.

[0075] In a possible implementation, the switch from controlling the vehicle's engine to operate in a lean burn mode to controlling the engine to operate in a rich burn mode is triggered due to the satisfaction of a first condition, where the first condition includes: the weight of nitrogen oxides adsorbed on the LNT during a target sub-period while controlling the engine to operate in the lean burn mode is greater than a nitrogen oxide adsorption weight threshold.

[0076] In an embodiment of the present application, for one instance of controlling the engine to operate in the lean burn mode, the duration elapsed since the start time of this instance of controlling the engine to operate in the lean burn mode is denoted as T, where 0 < T < TL. The engine control module ECM determines the duration elapsed since the start time of this instance of controlling the engine to operate in the lean burn mode, and the engine control module ECM determines the weight of adsorbed nitrogen oxides during the target sub-period through integral calculation. The start time of the target sub-period is the start time of operating in the lean burn mode, and the duration of the target sub-period is the duration elapsed since the start time of operating in the lean burn mode. The weight of nitrogen oxides adsorbed on the LNT during the target sub-period is denoted as M. M is compared with the target nitrogen oxide adsorption weight threshold Mmax. As an example, Mmax = 0.5 g. If M > Mmax, considering that the weight of nitrogen oxides adsorbed by the adsorbent in the LNT exceeds a certain weight, the amount of NOx released when controlling the engine to operate in the rich burn mode will be excessive, reducing the efficiency of NOx conversion. Therefore, when the weight of nitrogen oxides adsorbed on the LNT during the target sub-period while controlling the engine to operate in the lean burn mode is greater than the target nitrogen oxide adsorption weight threshold, the control switches from controlling the vehicle's engine to operate in the lean burn mode to controlling the engine to operate in the rich burn mode.

[0077] The weight of nitrogen oxides adsorbed on the LNT during the target sub-period can be calculated using the following formula:

[0078]

[0079] where M represents the weight of nitrogen oxides adsorbed on the LNT during the target sub-period; CNOx1 represents the NOx concentration measured by the nitrogen oxygen sensor before the LNT; CNOx represents the NOx concentration measured by the nitrogen oxygen sensor after the -LNT, and Vmflow represents the exhaust gas flow rate in the LNT. The exhaust gas flow rate in the LNT can be determined by the air-fuel ratio, fuel consumption, and air intake mass.

[0080] In an embodiment of the present application, for each of multiple different operating conditions of the engine, the nitrogen oxide adsorption weight threshold under this operating condition can be pre-calibrated. The calibrated nitrogen oxide adsorption weight threshold corresponds to a preset factor combination, and the preset factor combination corresponding to the calibrated nitrogen oxide adsorption weight threshold includes: this operating condition and other factors related to the nitrogen oxide adsorption weight threshold, such as the LNT temperature.

[0081] In this embodiment, the calibrated nitrogen oxide adsorption weight threshold for each operating condition and the preset factor combination corresponding to the calibrated nitrogen oxide adsorption weight threshold for each operating condition can be written into the engine controller module ECM.

[0082] In this embodiment, when obtaining a target nitrogen oxide adsorption weight threshold, a combination of factors for obtaining the target nitrogen oxide adsorption weight threshold is obtained. This combination of factors includes factors related to the nitrogen oxide adsorption weight threshold. The combination of factors for obtaining the target nitrogen oxide adsorption weight threshold is matched with a preset combination of factors corresponding to the calibrated nitrogen oxide adsorption weight threshold in the engine controller (ECM) to determine a target preset combination of factors that matches the combination of factors for obtaining the target nitrogen oxide adsorption weight threshold. The calibrated nitrogen oxide adsorption weight threshold corresponding to this target preset combination of factors is determined as the target nitrogen oxide adsorption weight threshold.

[0083] refer to Figure 5 It illustrates an example of the process for switching from controlling the engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode.

[0084] In this example, the weight M of nitrogen oxides adsorbed on the LNT during a target sub-period while operating in lean-burn mode is obtained. In this example, the target nitrogen oxide adsorption weight threshold Max is obtained based on the current LNT temperature and current operating conditions. If M > Max, the engine is switched to rich-burn mode.

[0085] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by determining that a second condition is met during the period when the engine is operating in lean-burn mode. The second condition includes: the first average nitrogen oxide adsorption rate of LNTs determined during the period when the engine is controlled to operate in lean-burn mode is less than a first nitrogen oxide adsorption rate threshold.

[0086] In this embodiment of the application, the module for calculating the average adsorption rate of nitrogen oxides (NOx) receives the average concentration of NOx in the exhaust gas before it enters the LNT from the LNT nitrogen oxide sensor 1, and the module for calculating the average adsorption rate of NOx receives the average concentration of NOx in the exhaust gas after LNT treatment from the nitrogen oxide sensor 2, and calculates the average adsorption rate of NOx.

[0087] In this embodiment, the average concentration of nitrogen oxides (NOx) in the exhaust gas before entering the LNT (Low-Temperature Toll Collection) within a certain time period can be subtracted from the average concentration of NOx in the exhaust gas after LNT treatment within that time period to obtain a difference. The duration of this time period is between a few seconds and tens of seconds, which are preset. Dividing this difference by the average concentration of NOx in the exhaust gas before entering the LNT within that time period yields the average NOx adsorption rate within that time period. The average NOx adsorption rate within a time period can be denoted as N. The average NOx adsorption rate of the LNT within a time period can be calculated using the following formula:

[0088] N=(C NOx1 -C NOx2 ) / C NOx1 x 100%.

[0089] C NOx1 This represents the average concentration of nitrogen oxides in the exhaust gas before it enters the LNT during that time period, C. NOx2 This indicates the average concentration of nitrogen oxides in the exhaust gas after LNT treatment during this time period. The duration of this time period ranges from a few seconds to tens of seconds.

[0090] In the embodiments of this application, the nitrogen oxide adsorption rate threshold can be denoted as Nmin.

[0091] In this embodiment of the application, in order to determine the first average nitrogen oxide adsorption rate of LNT, the average nitrogen oxide adsorption rate during a corresponding time period during which the engine is controlled to operate in lean-burn mode can be determined, and the average nitrogen oxide adsorption rate during the corresponding time period can be determined as the first average nitrogen oxide adsorption rate of LNT.

[0092] It should be noted that the first NOx adsorption rate threshold is related to factors such as the LNT catalyst formulation, LNT temperature, engine exhaust gas flow rate (exhaust flow rate), and the aging degree of the LNT. The first NOx adsorption rate threshold can be found in the NOx adsorption rate threshold table based on the LNT catalyst formulation, LNT temperature, exhaust flow rate, and LNT aging degree during engine operation in lean-burn mode. The NOx adsorption rate threshold table indicates the NOx adsorption rate threshold under the corresponding LNT catalyst formulation, corresponding LNT temperature, exhaust flow rate, and corresponding LNT aging degree.

[0093] In this embodiment of the application, for each of the multiple different operating conditions of the engine, a calibrated nitrogen oxide adsorption rate threshold can be pre-calibrated for that operating condition. The calibrated nitrogen oxide adsorption rate threshold corresponds to a preset combination of factors, which includes: the operating condition, and other factors related to the nitrogen oxide adsorption rate threshold, such as LNT temperature.

[0094] In the embodiments of this application, the calibrated nitrogen oxide adsorption rate threshold for each operating condition and the combination of factors corresponding to the calibrated nitrogen oxide adsorption rate threshold for each operating condition can be written into the engine controller ECM.

[0095] In this embodiment, when a corresponding nitrogen oxide adsorption rate threshold is obtained, a combination of factors for obtaining the corresponding nitrogen oxide adsorption rate threshold is obtained. This combination of factors includes factors related to the nitrogen oxide adsorption rate threshold. The corresponding nitrogen oxide adsorption rate threshold can be one of the first, second, or third nitrogen oxide adsorption rate thresholds in this embodiment. The combination of factors for obtaining the corresponding nitrogen oxide adsorption rate threshold is matched with a preset combination of factors corresponding to the calibrated nitrogen oxide adsorption rate threshold in the engine controller (ECM) to determine a target preset combination of factors that matches the combination of factors for obtaining the corresponding nitrogen oxide adsorption rate threshold. The calibrated nitrogen oxide adsorption rate threshold corresponding to this target preset combination of factors is determined as the corresponding nitrogen oxide adsorption rate threshold.

[0096] As an example, the combination of factors used to obtain the corresponding nitrogen oxide adsorption rate threshold includes: the operating conditions used to obtain the corresponding nitrogen oxide adsorption rate threshold, the LNT catalyst formulation, and the temperature of the LNT used to obtain the corresponding nitrogen oxide adsorption rate threshold.

[0097] As an example, under one operating condition, when the LNT temperature is 300°C, the highest average adsorption rate of nitrogen oxides is 99%. As the amount of adsorbed nitrogen oxides increases, the average adsorption rate decreases. Under this condition, the nitrogen oxide adsorption rate threshold is 85% when the LNT temperature is 300°C.

[0098] In this embodiment, when the first average nitrogen oxide adsorption rate of the LNT, determined during the period when the engine is controlled to operate in lean-burn mode, is less than the first nitrogen oxide adsorption rate threshold, the control of the vehicle's engine to operate in lean-burn mode is switched to rich-burn mode. Thus, even though the first lean-burn operation period has not been completed, the control of the engine to operate in rich-burn mode is switched ahead of schedule when the average nitrogen oxide adsorption rate decreases, thereby promptly eliminating the adverse effects caused by the decrease in the average nitrogen oxide adsorption rate and improving the overall exhaust gas treatment efficiency of the LNT.

[0099] In step S302, controlling the engine to run in a rich-fuel mode with a target rich-fuel ratio for a first rich-fuel running time includes: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

[0100] In this embodiment of the application, in order to ensure efficient regeneration of the LNT adsorbent when the engine is running in the rich-fuel mode, controlling the engine to run in the rich-fuel mode at the target rich-fuel ratio for a first rich-fuel running time includes: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

[0101] It's important to note that the air-fuel ratio is the mass (weight) ratio of air to fuel in the combustion gases of an engine. The excess air coefficient is the actual air-fuel ratio divided by the stoichiometric air-fuel ratio. The stoichiometric air-fuel ratio is closely related to the type and composition of the fuel; for example, the stoichiometric air-fuel ratio of gasoline is typically 14.6 or 14.7 (related to the gasoline's composition). The excess air coefficient is usually denoted by the symbol λ. Vehicle-mounted devices, such as wide-range oxygen sensors, can directly measure the excess air coefficient (λ) in the engine exhaust gases. Because of the one-to-one correspondence between λ (excess air coefficient) and the air-fuel ratio, it is customary for some to simply refer to λ (excess air coefficient) as the air-fuel ratio.

[0102] It should be noted that acting according to the air-fuel ratio is equivalent to acting according to the excess air coefficient corresponding to the air-fuel ratio.

[0103] If the corresponding unit on the vehicle receives the corresponding excess air coefficient for the corresponding air-fuel ratio, it can directly use that excess air coefficient to perform the corresponding action. As an example, if the unit controlling the engine operation of a hybrid vehicle receives the excess air coefficient corresponding to the target rich air-fuel ratio, then it controls the hybrid vehicle's engine to operate in rich mode with the excess air coefficient corresponding to the target rich air-fuel ratio. Controlling the hybrid vehicle's engine to operate in rich mode with the target rich air-fuel ratio is equivalent to controlling the hybrid vehicle's engine to operate in rich mode with the excess air coefficient corresponding to the target rich air-fuel ratio.

[0104] If the corresponding unit on the vehicle receives the air-fuel ratio, it may determine the excess air coefficient corresponding to the received air-fuel ratio based on the one-to-one correspondence between the excess air coefficient and the air-fuel ratio, and then take appropriate action based on the excess air coefficient corresponding to the received air-fuel ratio. Alternatively, the corresponding unit on the vehicle may also take appropriate action based on the received air-fuel ratio.

[0105] In the embodiments of this application, any description of the operation of controlling the air-fuel ratio or the description of the operation using the air-fuel ratio can be replaced with the excess air coefficient corresponding to the air-fuel ratio.

[0106] The excess air coefficient corresponding to the target rich air-fuel ratio can be denoted as λR1.

[0107] In this embodiment of the application, the target air-fuel ratio is obtained by calibrating with the goal of lower fuel consumption and higher fuel-rich regeneration power when operating in fuel-rich mode.

[0108] In one possible implementation, controlling the air-fuel ratio of the engine to a target rich air-fuel ratio includes: performing closed-loop control of the air-fuel ratio of the engine by adjusting the amount of fuel injected into the engine.

[0109] refer to Figure 6 It shows a schematic diagram of an example of closed-loop control of the air-fuel ratio of an engine.

[0110] In this example, while the engine is operating in a rich-fuel mode, the air-fuel ratio calculated by the front oxygen sensor is acquired. If the acquired air-fuel ratio is less than the target rich-fuel ratio, the fuel injection quantity is reduced. If the acquired air-fuel ratio is greater than the target rich-fuel ratio, the fuel injection quantity is increased.

[0111] In this embodiment of the application, the excess air coefficient corresponding to the target lean-burn air-fuel ratio can be denoted as λL.

[0112] In the embodiments of this application, the lean air-fuel ratio for each of the multiple operating conditions is pre-calibrated.

[0113] As an example, for each of the multiple operating conditions, when calibrating the lean-burn air-fuel ratio under that condition, the lean-burn air-fuel ratio is calibrated based on the optimal balance between fuel economy and power performance.

[0114] As an example, the target air-fuel ratio corresponds to an excess air coefficient between 0.85 and 0.95. As an example, the target air-fuel ratio corresponds to an excess air coefficient of 0.92.

[0115] In the embodiments of this application, the target rich air-fuel ratio can ensure that: fuel consumption is low during engine operation in rich air-fuel mode, and rich air-fuel is successfully achieved during engine operation in rich air-fuel mode. Alternatively, the excess air coefficient λR1 corresponding to the target rich air-fuel ratio can ensure that: fuel consumption is low during engine operation in rich air-fuel mode, and rich air-fuel is successfully achieved during engine operation in rich air-fuel mode.

[0116] In this embodiment, conditions for successful fuel enrichment can be preset. When the conditions for successful fuel enrichment are met, the fuel enrichment is determined to be successful. When the conditions for successful fuel enrichment are not met, the fuel enrichment is determined to be unsuccessful.

[0117] As an example, the conditions for successful fuel enrichment include: the average adsorption rate of any nitrogen oxide monitored during the operation of the engine in fuel enrichment mode is greater than the nitrogen oxide adsorption rate threshold used to determine whether fuel enrichment is successful.

[0118] It should be noted that the air-fuel ratio is related to factors such as operating conditions, duration of air-fuel enrichment, LNT catalyst formulation, and LNT temperature.

[0119] In the embodiments of this application, for each of the multiple operating conditions, the air-fuel ratio under that operating condition can be calibrated.

[0120] For a given operating condition and a calibrated air-fuel ratio, the calibrated air-fuel ratio corresponds to a preset combination of factors, which includes: the operating condition and other factors related to the air-fuel ratio.

[0121] For a calibrated rich air-fuel ratio under a certain operating condition, under the preset factor combination corresponding to the calibrated rich air-fuel ratio, controlling the engine to operate in rich mode with the calibrated rich air-fuel ratio can result in: low fuel consumption during engine operation in rich mode, and successful rich combustion during engine operation in rich mode.

[0122] In the embodiments of this application, the calibrated air-fuel ratio for each operating condition and the corresponding factor combination for the calibrated air-fuel ratio for each operating condition can be written into the engine controller ECM.

[0123] In this embodiment, when obtaining the target rich air-fuel ratio, the current combination of factors related to the rich air-fuel ratio is acquired. As an example, the current combination of factors related to the rich air-fuel ratio includes: current operating conditions, LNT catalyst formulation, and the current temperature of the LNT. The current combination of factors related to the rich air-fuel ratio is matched with the combination of factors in the engine controller (ECM) to determine a preset combination of factors that matches the current combination of factors related to the rich air-fuel ratio. The calibrated rich air-fuel ratio corresponding to the preset combination of factors is determined as the target rich air-fuel ratio.

[0124] In the embodiments of this application, when calibrating the rich-fuel ratio, the following considerations were taken into account: an excessively small rich-fuel ratio (i.e., overly rich) will lead to increased fuel consumption loss and higher emissions of HC, CO, and NH3. An excessively large rich-fuel ratio will result in unsuccessful rich-fuel operation.

[0125] It should be noted that, in the embodiments of this application, for a certain operating condition, a rich air-fuel ratio under that operating condition corresponds to a combination of factors, and the combination of factors corresponding to the rich air-fuel ratio includes: the operating condition and other factors related to the rich air-fuel ratio.

[0126] In the embodiments of this application, for a certain operating condition and a calibrated rich air-fuel ratio under that operating condition, under the combination of factors corresponding to the rich air-fuel ratio, the engine operates in rich mode with the calibrated rich air-fuel ratio, which can make: control the fuel consumption of the engine to be low during the operation of the engine in rich mode, and control the rich air-fuel ratio of the engine to be successful during the operation of the engine in rich mode.

[0127] As an example, for a given operating condition, when calibrating the rich air-fuel ratio under that condition, for each candidate rich air-fuel ratio: under a preset combination of factors including that operating condition, control the engine to run in rich mode with the candidate rich air-fuel ratio for the test duration to obtain the test result of the candidate rich air-fuel ratio.

[0128] In this example, the candidate rich air-fuel ratio test result indicates whether the engine can successfully achieve a rich air-fuel ratio within the test duration under a preset combination of factors including this operating condition.

[0129] In this example, the test results for the candidate rich air-fuel ratio also indicate the fuel consumption of the engine during the test duration in rich mode with the candidate rich air-fuel ratio under the combination of factors with this operating condition.

[0130] In this example, based on the test results of each candidate rich air-fuel ratio, it is determined whether there exists a candidate rich air-fuel ratio that can be used as the calibrated rich air-fuel ratio for this operating condition. The candidate rich air-fuel ratio that successfully achieves rich combustion and has the lowest fuel consumption during the test duration of controlling the engine in rich combustion mode with the candidate rich air-fuel ratio can be determined as the calibrated rich air-fuel ratio for this operating condition.

[0131] In the embodiments of this application, for each of the multiple operating conditions, the lean-burn running time and the rich-burn running time under that operating condition can be specified.

[0132] For a given operating condition, there is a calibrated lean-burn running time and a calibrated rich-burn running time. The calibrated lean-burn running time and the calibrated rich-burn running time correspond to a preset factor combination. The preset factor combination corresponding to the calibrated lean-burn running time and the calibrated rich-burn running time includes: the operating condition and other factors related to the lean-burn running time and the rich-burn running time.

[0133] As an example, other factors related to lean-burn and rich-burn operating times include: the catalyst formulation of the LNT, the LNT temperature, the NOx emission limit (average concentration), the energy loss caused by switching between controlling the engine to operate in lean-burn mode and controlling the engine to operate in rich-burn mode, and the rich-burn air-fuel ratio used when controlling the engine to operate in rich-burn mode.

[0134] It should be noted that, in the embodiments of this application, when calibrating the lean-burn running time and the rich-burn running time, the correlation between the ratio of lean-burn running time to rich-burn running time and the fuel consumption when controlling the engine to operate in rich-burn mode can be considered.

[0135] The ratio of lean-burn operating time to rich-burn operating time is denoted as TL / TR. The larger the TL and the smaller the TR, the larger the TL / TR, resulting in lower overall fuel consumption for the engine operating in rich-burn mode. Simultaneously, the engine produces less ammonia in rich-burn mode. However, a larger TL also leads to greater LNT adsorption and lower conversion efficiency.

[0136] It should be noted that, in the embodiments of this application, when calibrating the lean-burn and rich-burn operating times, the correlation between the lean-burn and rich-burn operating times and the regeneration frequency of the adsorbent in the LNT can also be considered. If the ratio of the calibrated lean-burn operating time to the calibrated rich-burn operating time is fixed, in some cases, the lower the L, the higher the regeneration frequency of the adsorbent in the LNT. Increasing the regeneration frequency of the adsorbent can improve the efficiency of NOx adsorption and increase the efficiency of NOx reduction during engine operation in rich-burn mode. As an example, compared with 30s L / 5s R, 60s L / 10s R has a higher adsorbent regeneration efficiency. However, too low L will result in excessively high frequency of engine operation in rich-burn mode, leading to high overall fuel consumption when the engine is operating in rich-burn mode.

[0137] In this embodiment of the application, the calibrated lean-burn running time and rich-burn running time under each operating condition can be written into the engine controller ECM.

[0138] In this embodiment, when the first lean-burn operating time and the first rich-burn operating time are obtained, the current combination of factors related to the lean-burn operating time and the rich-burn operating time is obtained. As an example, the current combination of factors related to the lean-burn operating time and the rich-burn operating time includes: the catalyst formulation of the LNT, the current temperature of the LNT, the nitrogen oxide emission limit (emission concentration), the energy loss caused by switching between controlling the engine to operate in lean-burn mode and controlling the engine to operate in rich-burn mode, and the target rich-burn air-fuel ratio. The current combination of factors related to the lean-burn operating time and the rich-burn operating time is matched with a preset combination of factors related to the lean-burn operating time and the rich-burn operating time in the engine controller ECM to determine a preset combination of factors that matches the current combination of factors related to the lean-burn operating time and the rich-burn operating time. The lean-burn operating time and the rich-burn operating time corresponding to the preset combination of factors are determined as the first lean-burn operating time and the first rich-burn operating time.

[0139] In one possible implementation, the method further includes: if step S301 is triggered because the second condition is determined to be met during the operation of the engine in lean-burn mode, that is, step S301 is triggered because the first average nitrogen oxide adsorption rate of LNT is less than the first nitrogen oxide adsorption rate threshold during the operation of the engine in lean-burn mode, then step S303 is included after step S302.

[0140] In step S303, the average adsorption rate of the second nitrogen oxides of the LNT is determined; when the average adsorption rate of the second nitrogen oxides of the LNT is less than the threshold value of the second nitrogen oxide adsorption rate, a first desulfurization operation is performed. The first desulfurization operation includes: controlling the temperature of the LNT to a temperature within a first desulfurization temperature range, and when the temperature of the LNT is within the first desulfurization temperature range, controlling the engine to run in lean-burn mode with a target lean-burn air-fuel ratio for a first lean-burn running time.

[0141] It should be noted that when the engine is operated in lean-burn mode at high temperature (550℃), thermal decomposition will occur (the specific thermal decomposition temperature and degree depend on the specific LNT formulation), causing the nitrogen oxides in the LNT to desorb.

[0142] It should be noted that the completion of the first desulfurization operation can be determined by the duration of the first lean-burn operation when the engine is running in lean-burn mode with the target lean-burn air-fuel ratio.

[0143] To determine the second average nitrogen oxide adsorption rate of the LNT, the average nitrogen oxide adsorption rate within a time period following the execution of step S302 can be obtained, and this average adsorption rate is defined as the second average nitrogen oxide adsorption rate of the LNT. The start time of the time period following the execution of step S302 is the time when step S302 is completed, and the duration of this time period can be a preset duration, such as 5 seconds. As an example, within the time period following the execution of step S302, the engine is controlled to operate at least once according to a calibrated lean-fuel-rich duration. Controlling the engine to operate at the calibrated lean-fuel-rich duration once includes: first controlling the engine to operate in lean-fuel mode under normal lean-fuel conditions for a first lean-fuel duration, and then controlling the engine to operate in rich-fuel mode under normal rich-fuel conditions for a first rich-fuel duration.

[0144] It should be noted that the second nitrogen oxide adsorption rate threshold is related to factors such as the LNT catalyst formulation, LNT temperature, and LNT aging degree. The second nitrogen oxide adsorption rate threshold can be found in the nitrogen oxide adsorption rate threshold table based on the LNT catalyst formulation, the LNT temperature during engine operation in lean-burn mode, and the LNT aging degree.

[0145] In this embodiment, it is considered that if the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by the first average nitrogen oxide adsorption rate of LNT being less than the first nitrogen oxide adsorption rate threshold during the period when the engine is controlled to operate in lean-burn mode, and after the engine is controlled to operate in rich-burn mode with the target rich-burn air-fuel ratio for a first rich-burn running time, if the average nitrogen oxide adsorption rate is still low, that is, the second average nitrogen oxide adsorption rate of LNT is less than the second nitrogen oxide adsorption rate threshold, then "sulfur poisoning" may occur.

[0146] The sulfur in exhaust gases mainly originates from the sulfur contained in fuel oil. The sulfur emitted by engines is primarily sulfur dioxide (SO2). SO2 is easily adsorbed onto lamp touchscreens (LNTs) under low-temperature, especially lean-burn conditions, leading to a decrease in LNT activity and its ability to adsorb NOx. SO2 adsorbed on LNTs is easily oxidized to SO3 by noble metal catalysts under lean-burn conditions. SO3 readily reacts with the LNT adsorbent to produce sulfates such as BaSO4, further reducing the amount of NOx adsorbent on the LNT. BaSO4 is very stable under lean-burn conditions and requires high-temperature, rich-burn decomposition.

[0147] At this point, the first desulfurization operation is performed to eliminate the adverse effects caused by SO2 poisoning. Through this first desulfurization operation, SO2 is effectively released, achieving desulfurization and restoring the NOx adsorption activity of the adsorbent in the LNT. The first desulfurization operation is used to remove SO2. During the execution of the first desulfurization operation, SO2 is removed.

[0148] As an example, the first desulfurization temperature range is 450–550°C.

[0149] During desulfurization operations, controlling the temperature within the desulfurization temperature range includes: when the LNT temperature Temp1 is less than 450°C, raising the LNT temperature to a temperature within the Tbest2 temperature range of 450°C to 550°C; and when the LNT temperature Temp1 is greater than 550°C, lowering the LNT temperature to a temperature within the 450°C to 550°C temperature range.

[0150] In one possible implementation, after the first desulfurization operation in step S303 is completed, the process further includes step S304. In step S304, the average adsorption rate of the third nitrogen oxides of the LNT is determined; when the average adsorption rate of the third nitrogen oxides is less than the third nitrogen oxide adsorption rate threshold, a second desulfurization operation is performed.

[0151] It should be noted that, in this embodiment of the application, multiple steps involving the second desulfurization operation may be executed in parallel during vehicle operation. At least two of steps S304, S305, S306, and S307 may be executed in parallel.

[0152] It should be noted that if a second desulfurization operation is performed because the average adsorption rate of the third nitrogen oxide is less than the adsorption rate threshold of the third nitrogen oxide, the need for the second desulfurization operation is determined by comparing the amount of sulfur accumulated on the LNT with the cumulative threshold. In this case, the second desulfurization operation can continue. After the second desulfurization operation is completed, the amount of sulfur accumulated on the LNT is reset to zero, and the sulfur accumulation on the LNT is recounted.

[0153] To determine the third average nitrogen oxide adsorption rate of the LNT, the average nitrogen oxide adsorption rate during the time period following the execution of the first desulfurization operation in step S303 can be obtained. This average nitrogen oxide adsorption rate during the time period following the execution of the first desulfurization operation in step S303 is defined as the third average nitrogen oxide adsorption rate of the LNT. The start time of the execution of the first desulfurization operation in step S303 is the time when the first desulfurization operation in step S303 is completed. The duration of the time period following the execution of the first desulfurization operation in step S303 can be a preset duration, such as 15 seconds. As an example, during the time period following the execution of the first desulfurization operation in step S303, the engine is controlled to operate at least once according to a calibrated lean-fuel-rich operation duration. Controlling the engine to operate at the calibrated lean-fuel-rich operation duration includes: first controlling the engine to operate in a lean-fuel mode under normal lean-fuel conditions for a first lean-fuel operation duration, and then controlling the engine to operate in a rich-fuel mode under normal rich-fuel conditions for a first rich-fuel operation duration.

[0154] It should be noted that the third NOx adsorption rate threshold is related to factors such as the LNT catalyst formulation, exhaust flow rate, LNT temperature, and LNT aging degree. The third NOx adsorption rate threshold can be found in the NOx adsorption rate threshold table based on the LNT catalyst formulation, the LNT temperature during engine operation in lean-burn mode, and the LNT aging degree.

[0155] The second desulfurization operation includes: controlling the temperature of the LNT to a temperature within the second desulfurization temperature range, and when the temperature of the LNT is within the second desulfurization temperature range, controlling the engine to operate in lean-burn mode for a second lean-burn duration, and controlling the engine to operate in rich-burn mode for a second rich-burn duration, wherein the second rich-burn duration is greater than the second lean-burn duration, and the ratio of the second lean-burn duration to the second rich-burn duration is a preset ratio.

[0156] Controlling the engine to operate in lean-burn mode for a second lean-burn duration, and controlling the engine to operate in rich-burn mode for a second rich-burn duration, can include: controlling the engine to operate lean-burn and rich-burn for a calibrated duration multiple times. Controlling the engine to operate lean-burn and rich-burn for a calibrated duration once includes: first controlling the engine to operate in lean-burn mode under normal lean-burn conditions for a first lean-burn duration, and then controlling the engine to operate in rich-burn mode under normal rich-burn conditions for a first rich-burn duration. As an example, the duration of the second desulfurization operation is 5-20 minutes.

[0157] It should be noted that the completion of the second desulfurization operation can be determined in response to the engine operating in lean-burn mode for a second lean-burn duration and the engine operating in rich-burn mode for a second rich-burn duration.

[0158] Specifically, when the engine is operated in rich-fuel mode for a second rich-fuel operating time, the rich-fuel air-fuel ratio of the engine may be the same as or different from the target rich-fuel air-fuel ratio. The excess air coefficient corresponding to the rich-fuel air-fuel ratio of the engine when operating in rich-fuel mode for a second rich-fuel operating time can be denoted as λR2.

[0159] The second desulfurization operation is used to eliminate the adverse effects caused by SO3 poisoning. SO3 poisoning causes the formation of BaSO4 and Ce(SO4)2 in metal oxide adsorbents, mainly composed of Ba and Ce. The second desulfurization operation removes SO3, which is actually the decomposition of sulfates. SO3 can be removed through a high-temperature, fuel-rich second desulfurization operation.

[0160] During the second fuel-rich operation period when the engine is running in fuel-rich mode, sulfates such as BaSO4 and Ce(SO)2 in the LNT are decomposed. Under high-temperature fuel-rich conditions, sulfur is released as H2S, SO2, and COS, achieving desulfurization and restoring the adsorption activity of the adsorbent for NOx.

[0161] As an example, the second desulfurization temperature range is 600℃~750℃.

[0162] As an example, the ratio of the second lean-burn running time to the second rich-burn running time is 1:9.

[0163] S304 takes into account that if, after a desulfurization operation is completed, the average adsorption rate of nitrogen oxides is less than the corresponding nitrogen oxide adsorption rate threshold, considering that the average adsorption rate of nitrogen oxides may be low due to sulfates such as BaSO4 produced by SO3 poisoning, desulfurization operation needs to be carried out in a fuel-rich atmosphere.

[0164] S304 also considers that when the engine is performing desulfurization, for adsorbents mainly composed of metal oxides such as BaO, during the second desulfurization operation, the engine switches between lean-burn mode and rich-burn mode. That is, controlling the second lean-burn operation time in lean-burn mode and controlling the second rich-burn operation time in rich-burn mode can avoid excessively high concentrations of sulfides such as hydrogen sulfide in the exhaust gas, which would cause a strong pungent odor.

[0165] In one possible implementation, after the second desulfurization operation in step S304 is completed, the process further includes step S305. In step S305, the average adsorption rate of the fourth nitrogen oxides by the LNT on the vehicle is determined; if the average adsorption rate of the fourth nitrogen oxides by the LNT is less than the fourth nitrogen oxide adsorption rate threshold, the second desulfurization operation is performed again; after the second desulfurization operation in step S305, i.e., the re-performed second desulfurization operation, is completed, the average adsorption rate of the fifth nitrogen oxides by the LNT is determined; if the average adsorption rate of the fifth nitrogen oxides is less than the fifth nitrogen oxide adsorption rate threshold, the LNT may be unable to eliminate sulfur poisoning, causing significant catalyst degradation, and an alarm is triggered.

[0166] In one possible implementation, the fourth average nitrogen oxide adsorption rate of LNTs on the vehicle can be determined in response to the completion of the second desulfurization operation in step S304.

[0167] The warning is used to alert the vehicle driver to the risk of excessive NOx emissions from the engine. The warning is based on the following considerations: if multiple secondary desulfurization operations fail to improve the average NOx adsorption rate, it could be due to at least one of the following reasons: catalyst degradation in the LNT, NOx sensor malfunction, or other issues, leading to a risk of excessive NOx emissions from the engine. Therefore, a warning is necessary to alert the driver of this risk.

[0168] In one possible implementation, the vehicle is equipped with a particulate filter (GPF). After the second desulfurization operation in step S304 is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT on the vehicle, the method further includes step S306. In step S306, a first exhaust back pressure of the GPF on the vehicle is obtained, and if the first exhaust back pressure is greater than a lower exhaust back pressure threshold, a first GPF active regeneration operation is performed in response to the first exhaust back pressure being greater than the lower exhaust back pressure threshold. The first GPF active regeneration operation includes controlling the temperature of the GPF on the vehicle within the active regeneration temperature range of the GPF, and controlling the engine to operate at a target lean air-fuel ratio for a first active regeneration duration, wherein the magnitude of the first active regeneration duration is positively correlated with the magnitude of the back pressure of the GPF. Determining the fourth average nitrogen oxide adsorption rate of the LNT in step S306 includes determining the fourth average nitrogen oxide adsorption rate of the LNT in response to the completion of the first GPF active regeneration operation. When the average adsorption rate of the fourth nitrogen oxide is less than the adsorption rate threshold of the fourth nitrogen oxide, the second desulfurization operation is performed again. After the second desulfurization operation is completed, the average adsorption rate of the fifth nitrogen oxide of LNT is determined. When the average adsorption rate of the fifth nitrogen oxide is less than the adsorption rate threshold of the fifth nitrogen oxide, it indicates that the desulfurization has failed and the LNT catalyst is at risk of failure, and an alarm is issued.

[0169] In one possible implementation, the vehicle is equipped with a particulate filter (GPF). After the second desulfurization operation in step S304 is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT on the vehicle, the method further includes step S307. In step S307, the first exhaust back pressure of the GPF on the vehicle is obtained. If the first exhaust back pressure is not greater than the exhaust back pressure lower limit threshold, then determining the fourth average nitrogen oxide adsorption rate of the LNT in step S305 includes: determining the fourth average nitrogen oxide adsorption rate of the LNT in response to the first exhaust back pressure not being greater than the exhaust back pressure lower limit threshold. When the fourth average nitrogen oxide adsorption rate is less than the fourth nitrogen oxide adsorption rate threshold, the second desulfurization operation is performed again; after the second desulfurization operation is completed, the fifth average nitrogen oxide adsorption rate of the LNT is determined; when the fifth average nitrogen oxide adsorption rate is less than the fifth nitrogen oxide adsorption rate threshold, it indicates that desulfurization has failed, the LNT catalyst is at risk of failure, and an alarm is issued.

[0170] It should be noted that the completion of the first GPF active regeneration operation can be determined in response to the first active regeneration duration in which the engine operates at the target lean air-fuel ratio.

[0171] It should be noted that if, in response to the completion of the second desulfurization operation in step S304, the average adsorption rate of fourth nitrogen oxides (NOx) of the LNT on the vehicle is determined, then, in order to determine the average NOx adsorption rate of the LNT, the average NOx adsorption rate during the time period following the execution of the second desulfurization operation in step S304 can be obtained, and the average NOx adsorption rate during the time period following the execution of the second desulfurization operation in step S304 is determined as the average NOx adsorption rate of the LNT. The start time of the time period following the execution of the second desulfurization operation in step S304 is the time when the second desulfurization operation in step S304 is completed, and the duration of the time period following the execution of the second desulfurization operation in step S304 can be a preset duration, such as 15 seconds.

[0172] It should be noted that if, in response to the completion of the first GPF active regeneration operation, the average adsorption rate of the fourth nitrogen oxides of the LNT is determined, then, in order to determine the average adsorption rate of the fourth nitrogen oxides of the LNT, the average adsorption rate of nitrogen oxides during the time period following the execution of the first GPF active regeneration operation in step S306 can be obtained, and the average adsorption rate of nitrogen oxides during the time period following the execution of the first GPF active regeneration operation in step S306 is determined as the average adsorption rate of the fourth nitrogen oxides of the LNT. The start time of the time period following the execution of the first GPF active regeneration operation in step S306 is the time when the first GPF active regeneration operation in step S306 is completed, and the duration of the time period following the execution of the first GPF active regeneration operation in step S306 can be a preset duration, such as 15 seconds. As an example, during the time period following the execution of the first GPF active regeneration operation in step S306, controlling the engine to operate at least once for a calibrated duration of lean-fuel-rich combustion includes: first controlling the engine to operate in lean-fuel mode under normal lean-fuel conditions for a first lean-fuel duration, and then controlling the engine to operate in rich-fuel mode under normal rich-fuel conditions for a first rich-fuel duration.

[0173] It should be noted that if the average adsorption rate of the fourth nitrogen oxides of the LNT is determined in response to the first exhaust back pressure not exceeding the lower limit threshold, then to determine the average adsorption rate of the fourth nitrogen oxides of the LNT, the average adsorption rate of nitrogen oxides during the time period after the determination that the first exhaust back pressure is not exceeding the lower limit threshold can be obtained. This average adsorption rate of nitrogen oxides during the time period after the determination that the first exhaust back pressure is not exceeding the lower limit threshold is defined as the average adsorption rate of the fourth nitrogen oxides of the LNT. The start time of the time period after the determination that the first exhaust back pressure is not exceeding the lower limit threshold is the moment when the first exhaust back pressure is determined to be not exceeding the lower limit threshold. The duration of the time period after the determination that the first exhaust back pressure is not exceeding the lower limit threshold can be a preset duration, such as 15 seconds.

[0174] It should be noted that the fourth nitrogen oxide adsorption rate threshold is related to factors such as the LNT catalyst formulation, LNT temperature, and LNT aging degree. The fourth nitrogen oxide adsorption rate threshold can be found in the nitrogen oxide adsorption rate threshold table based on the LNT catalyst formulation, the LNT temperature during engine operation in lean-burn mode, and the LNT aging degree.

[0175] To determine the fifth average nitrogen oxide adsorption rate of the LNT, the average nitrogen oxide adsorption rate during the time period following the execution of the second desulfurization operation in step S305 can be obtained. This average nitrogen oxide adsorption rate during the time period following the execution of the second desulfurization operation in step S305 is defined as the fifth average nitrogen oxide adsorption rate of the LNT. The start time of the time period following the execution of the second desulfurization operation in step S305 is the time when the second desulfurization operation in step S305 is completed. The duration of the time period following the execution of the second desulfurization operation in step S305 can be a preset duration, such as 5 seconds. As an example, during the time period following the execution of the second desulfurization operation in step S305, the engine is controlled to operate at least once according to a calibrated lean-fuel-rich operation duration. Controlling the engine to operate at the calibrated lean-fuel-rich operation duration includes: first controlling the engine to operate in a lean-fuel mode under normal lean-fuel conditions for a first lean-fuel operation duration, and then controlling the engine to operate in a rich-fuel mode under normal rich-fuel conditions for a first rich-fuel operation duration.

[0176] It should be noted that the fifth nitrogen oxide adsorption rate threshold is related to factors such as the LNT catalyst formulation, LNT temperature, and LNT aging degree. The fifth nitrogen oxide adsorption rate threshold can be found in the nitrogen oxide adsorption rate threshold table based on the LNT catalyst formulation, the LNT temperature during engine operation in lean-burn mode, and the LNT aging degree.

[0177] The first GPF active regeneration operation is used to regenerate the GPF. This operation oxidizes and burns away the particulate matter in the GPF, restoring its particulate filtration performance.

[0178] The first exhaust back pressure is denoted as Pback1. The larger the first exhaust back pressure Pback1, the more GPF regeneration is needed, and the longer the first active regeneration time in the first GPF active regeneration operation in step S306.

[0179] The duration of the first active regeneration is denoted as T_gpf. T_gpf = K * Pback1.

[0180] Step S306 considers that after the second desulfurization operation is completed, the exhaust temperature is high, ranging from 600℃ to 750℃. Compared to raising the temperature from a lower temperature to the GPF active regeneration temperature, this method consumes less fuel and takes less time to bring the GPF temperature within the GPF active regeneration temperature range. This improves the overall processing efficiency of the LNT and reduces the amount of fuel consumed to control the GPF temperature within the GPF active regeneration temperature range, thus reducing fuel consumption. It also reduces the number of times the GPF needs to be regenerated and heated separately, further reducing fuel consumption.

[0181] refer to Figure 7 , which shows a schematic flow diagram of an example of post-treatment using LNT and GPF.

[0182] In this example, during the period of controlling the engine to operate in the lean burn mode, the first average NOx adsorption rate N1 of the LNT is obtained. If N1 < Nmin1, the engine is controlled to operate in the rich burn mode for the first rich burn operation duration. After controlling the engine to operate in the rich burn mode for the first rich burn operation duration, the second average NOx adsorption rate N2 of the LNT is obtained.

[0183] In this example, if N2 is not less than the second NOx adsorption rate threshold Nmin2, the engine is operated in the lean burn - rich burn mode according to the calibrated duration. Operating the engine in the lean burn - rich burn mode according to the calibrated duration includes: first controlling the engine to operate in the lean burn mode under conventional lean burn conditions for the first lean burn operation duration, and then controlling the engine to operate in the rich burn mode under conventional rich burn conditions for the first rich burn operation duration.

[0184] In this example, if N2 < Nmin2, the first desulfurization operation is performed. The first desulfurization operation includes: controlling the temperature of the LNT to be within the range of 450 - 550 °C; controlling the engine to operate in the lean burn mode for the first lean burn operation duration.

[0185] In this example, after the first desulfurization operation is completed, the third average NOx adsorption rate N3 of the LNT is determined. If N3 < Nmin3, the second desulfurization operation is performed. The second desulfurization operation includes: controlling the temperature of the LNT to be within the range of 600 °C - 700 °C, controlling the engine to operate in the lean burn mode for the second lean burn operation duration, and controlling the engine to operate in the rich burn mode for the second rich burn operation duration.

[0186] In this example, the first exhaust back pressure of the GPF is obtained. If the first exhaust back pressure is greater than the exhaust back pressure lower limit threshold, the first GPF active regeneration operation is performed. The first GPF active regeneration operation includes: controlling the temperature of the GPF within the GPF active regeneration temperature range, and controlling the engine to operate at the target lean burn air-fuel ratio for the first active regeneration duration.

[0187] In this example, after the first GPF active regeneration operation is completed, the fourth average NOx adsorption rate N4 of the LNT is determined; when N4 < Nmin4, the second desulfurization operation is performed.

[0188] In this example, after the second desulfurization operation performed due to N4 < Nmin4 is completed, the fifth average NOx adsorption rate N5 of the LNT is determined.

[0189] An alarm is triggered when N5 is less than the fifth nitrogen oxide adsorption rate threshold Nmin5.

[0190] In one possible implementation, step S308 is also included.

[0191] In step S308, the vehicle's fuel consumption is obtained, and the sulfur content corresponding to the vehicle's fuel consumption is determined; it is determined whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount; when it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount, a second desulfurization operation is performed; after the second desulfurization operation in step S308 is completed, when the vehicle is equipped with a particulate filter (GPF), the second exhaust back pressure of the GPF on the vehicle is obtained; when the second exhaust back pressure is greater than the lower limit threshold of the exhaust back pressure, a first GPF active regeneration operation is performed, the first GPF active regeneration operation including: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the vehicle's engine to run at a target lean air-fuel ratio for a first active regeneration duration.

[0192] As an example, the cumulative upper limit threshold is 2-3 grams (g) of sulfur per liter of catalyst.

[0193] It should be noted that the vehicle's fuel consumption obtained in step S308 should be understood as a variable. The steps of obtaining the vehicle's fuel consumption, determining the sulfur content corresponding to that fuel consumption, and determining whether the cumulative sulfur content on the LNT corresponding to that sulfur content exceeds the upper limit threshold can be performed periodically.

[0194] In one possible implementation, each time the cumulative sulfur content on the LNT corresponding to the sulfur content is determined to be greater than the upper limit threshold, the vehicle's fuel consumption can be reset to zero and the vehicle's fuel consumption can be recounted.

[0195] In another possible implementation, the fuel consumption of the vehicle obtained in step S308 is the fuel consumption of the vehicle after the most recent completion of the second desulfurization operation. It should be noted that if the fuel consumption of the vehicle obtained in step S308 is the fuel consumption of the vehicle after the most recent completion of the second desulfurization operation, then in response to the completion of the second desulfurization operation, the accumulated sulfur content on the LNT is reset to zero, and the accumulated sulfur content on the LNT is recounted.

[0196] It should be noted that the upper limit threshold for cumulative amount is greater than the lower limit threshold for cumulative amount.

[0197] It should be noted that the sulfur content corresponding to fuel consumption can be understood as the sulfur content in the fuel consumed.

[0198] The sulfur content corresponding to fuel consumption can be determined according to the relevant standards for sulfur concentration in fuel.

[0199] A correlation between fuel consumption and sulfur content can be established in advance. In step S308, based on the correlation between fuel consumption and sulfur content and the fuel consumption of the vehicle, the amount of sulfur accumulated on the LNT corresponding to the fuel consumption of the vehicle is determined.

[0200] It should be noted that the cumulative sulfur content on LNTs can be understood as the amount of sulfur accumulated on the LNTs.

[0201] A correlation between sulfur content and sulfur accumulation can be established in advance. In step S308, based on the correlation between sulfur content and sulfur accumulation, and the sulfur content determined in step S308, which corresponds to the sulfur content of the vehicle's fuel consumption, the sulfur accumulation on the LNT corresponding to the sulfur content determined in step S308 is determined.

[0202] It should be noted that the greater the second exhaust back pressure, the more GPF regeneration is needed, and the longer the first active regeneration time in the first GPF active regeneration operation in step S308.

[0203] Step S308 considers that if the cumulative sulfur content on the LNT corresponding to this sulfur content exceeds the upper limit threshold, it indicates that the current moment is approaching the point where a second desulfurization operation needs to be initiated. At this time, the second desulfurization operation can be performed earlier to remove sulfates (e.g., BaSO4). After the second desulfurization operation is completed, the exhaust temperature is high, between 600℃ and 750℃. Compared to raising the temperature from a lower temperature to the GPF active regeneration temperature, less fuel is consumed and the time is shorter to bring the GPF temperature within the GPF active regeneration temperature range. When the second exhaust back pressure exceeds the lower limit threshold, less fuel is consumed and the time is shorter to perform the first GPF active regeneration operation, improving the overall processing efficiency of the LNT and reducing the amount of fuel consumed to control the GPF temperature within the GPF active regeneration temperature range, thus reducing fuel consumption. This also reduces the number of separate GPF regeneration heating cycles, further reducing fuel consumption.

[0204] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the method further includes step S309. In step S309, the third exhaust back pressure of the GPF is acquired; when the third exhaust back pressure of the GPF is greater than the upper limit threshold of the exhaust back pressure, a second GPF active regeneration operation is performed. The second GPF active regeneration operation includes: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to operate at a target lean air-fuel ratio for a second active regeneration duration; after the second GPF active regeneration operation is completed, the fuel consumption of the vehicle after the most recent second desulfurization operation is acquired, and the sulfur content corresponding to the fuel consumption is determined; it is determined whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold of the cumulative amount; when the cumulative sulfur content on the LNT corresponding to the sulfur content determined in step S309 is greater than the lower limit threshold of the cumulative amount, the second desulfurization operation is performed.

[0205] It should be noted that the upper limit threshold of exhaust back pressure is greater than the lower limit threshold of exhaust back pressure.

[0206] A correlation between fuel consumption and sulfur content can be established in advance. In step S309, based on the correlation between fuel consumption and sulfur content and the fuel consumption of the vehicle after the most recent second desulfurization operation, the sulfur content corresponding to the fuel consumption of the vehicle after the most recent second desulfurization operation is determined.

[0207] In step S309, based on the correlation between sulfur content and sulfur accumulation, and the sulfur content determined in step S309, which is the sulfur content corresponding to the fuel consumption of the vehicle after the most recent second desulfurization operation, the sulfur accumulation on LNT corresponding to the sulfur content determined in step S309 is obtained.

[0208] It should be noted that the completion of the second GPF active regeneration operation can be determined in response to the duration of the second active regeneration operation when the engine operates at the target lean air-fuel ratio.

[0209] The second active GPF regeneration operation is used to regenerate the GPF. This operation oxidizes and burns away the particulate matter in the GPF, restoring its particulate filtration performance.

[0210] As an example, the active regeneration temperature range of GPF is 550℃~650℃.

[0211] As an example, the upper limit threshold for exhaust back pressure is 50 kPa.

[0212] Step S309 considers that after the GPF active regeneration, i.e., after the second GPF active regeneration operation is completed, the exhaust temperature is high. Compared to raising the LNT temperature from a lower temperature to the second desulfurization temperature range, less fuel and a shorter time are required to bring the LNT temperature into the second desulfurization temperature range, allowing the second desulfurization operation to be performed earlier to remove sulfates. This improves the overall treatment efficiency of the LNT and reduces the amount of fuel consumed to control the LNT temperature within the second desulfurization temperature range, thus reducing fuel consumption.

[0213] refer to Figure 8 It shows a flowchart of another example of post-processing using LNT and GPF.

[0214] In this example, the second exhaust back pressure measured by the GPF differential pressure sensor is acquired. If the second exhaust back pressure is greater than the upper limit threshold of the exhaust back pressure, a second GPF active regeneration operation is executed. The second GPF active regeneration operation includes: controlling the GPF temperature within the GPF active regeneration temperature range, and controlling the engine to operate at the target lean-burn air-fuel ratio for the second active regeneration duration. After the second GPF active regeneration operation is completed, the fuel consumption of the vehicle after the most recent second desulfurization operation is acquired, the sulfur content corresponding to the fuel consumption is determined, and the cumulative sulfur content on the LNT corresponding to the sulfur content is determined to be greater than the lower limit threshold of the cumulative amount. A second desulfurization operation is then executed, which includes: controlling the LNT temperature to be within the range of 600℃ to 750℃, controlling the engine to operate in lean-burn mode for the second lean-burn duration, and controlling the engine to operate in rich-burn mode for the second rich-burn duration.

[0215] After the second desulfurization operation is completed, the engine will operate under the specified lean-fuel-rich fuel cycle for the specified duration. This includes: first, controlling the engine to run under the normal lean-fuel condition in lean-fuel mode for the first lean-fuel cycle duration, and then controlling the engine to run under the normal rich fuel condition in rich fuel mode for the first rich fuel cycle duration.

[0216] In one possible implementation, step S310 is also included.

[0217] In step S310, when a shutdown command for the engine is received and the conditions for supplemental rich fuel are met, a supplemental rich fuel operation is performed. The supplemental rich fuel operation includes: controlling the engine to run in rich fuel mode with a target rich fuel air-fuel ratio for a first rich fuel running time, and controlling the engine to shut down after controlling the engine to run in rich fuel mode with a target rich fuel air-fuel ratio for the first rich fuel running time.

[0218] Step S310 ensures the regeneration of the adsorbent in the LNT, enabling it to effectively adsorb nitrogen oxides (NOx) from the exhaust gas during the next lean-burn start-up of the engine, thus ensuring a high average NOx adsorption rate. It also considers that if the supplemental rich-fuel conditions are not met, it indicates that the LNT adsorbent still has the capacity to adsorb a large amount of NOx. This allows for the adsorption of more NOx from the exhaust gas after the next vehicle start-up, enabling the engine to be directly shut down without control. The engine can then operate in rich-fuel mode at the target rich-fuel ratio for the first rich-fuel period, saving fuel consumption.

[0219] In the embodiments of this application, multiple supplementary fuel-rich conditions are preset.

[0220] In one possible implementation, a first supplementary fuel-rich condition and a second supplementary fuel-rich condition are set.

[0221] The first supplementary rich-fuel condition is: the average nitrogen oxide adsorption rate determined in response to the engine receiving a shutdown signal is less than the sixth nitrogen oxide adsorption rate threshold. The average nitrogen oxide adsorption rate determined in response to the engine receiving a shutdown signal can be the average nitrogen oxide adsorption rate during the period when the engine was most recently controlled to operate in lean-burn mode.

[0222] The second supplementary rich-fuel condition is: the weight of nitrogen oxides adsorbed on the LNT, determined in response to the engine receiving a shutdown signal, is greater than a weight threshold. The weight of nitrogen oxides adsorbed on the LNT, determined in response to the engine receiving a shutdown signal, can be the weight of nitrogen oxides adsorbed on the LNT during the most recent period when the engine was controlled to operate in lean-burn mode.

[0223] When a sixth nitrogen oxide (NOx) adsorption rate threshold is obtained, a combination of factors used to obtain this threshold is acquired. This combination includes: the operating conditions during the most recent operation in rich-fuel mode, engine exhaust flow rate, LNT catalyst formulation, and the temperature of the LNT during the most recent operation in rich-fuel mode. This combination is then matched with a preset combination of factors corresponding to the calibrated NOx adsorption rate threshold in the engine controller (ECM) to determine a target preset combination of factors that matches the combination used to obtain the corresponding NOx adsorption rate threshold. The calibrated NOx adsorption rate threshold corresponding to this target preset combination of factors is then determined as the sixth NOx adsorption rate threshold.

[0224] As an example, the sixth nitrogen oxide adsorption threshold is 85%.

[0225] In one possible implementation, the method further includes: determining the future desulfurization time of the second desulfurization operation based on the fuel consumption used to determine the future desulfurization time of the second desulfurization operation, wherein the fuel consumption used to determine the future desulfurization time of the second desulfurization operation is determined based on multiple target fuel consumption values ​​corresponding to the second desulfurization operation, and the target fuel consumption values ​​corresponding to the second desulfurization operation are the fuel consumption of the vehicle during the time period between the start times of two adjacent second desulfurization operations; determining the future desulfurization time at which the second desulfurization operation needs to be performed, and then starting to execute the second desulfurization operation.

[0226] As an example, the second desulfurization operation corresponds to N target fuel consumption values. The first target fuel consumption value corresponding to the second desulfurization operation is the vehicle's fuel consumption during the time period between the start time of the first second desulfurization operation and the start time of the second second desulfurization operation. The second target fuel consumption value corresponding to the second desulfurization operation is the vehicle's fuel consumption during the time period between the start time of the second second desulfurization operation and the start time of the third second desulfurization operation. And so on.

[0227] As an example, the average of multiple target fuel consumption values ​​corresponding to the second desulfurization operation is determined as the fuel consumption value used to determine the future desulfurization time of the second desulfurization operation.

[0228] In this embodiment of the application, the change in the vehicle's fuel consumption is monitored. In response to monitoring that the vehicle's fuel consumption reaches the fuel consumption required to determine the future desulfurization time of the target desulfurization operation after the start time of the most recently executed target desulfurization operation, the time when the vehicle's fuel consumption reaches the fuel consumption required to determine the future desulfurization time of the target desulfurization operation after the start time of the most recently executed target desulfurization operation is determined as the future time.

[0229] Determining the future desulfurization time required for the second desulfurization operation takes into account that the vast majority of sulfur in engine exhaust originates from sulfur in the fuel. The amount of sulfur accumulated on the fuel tank (LNT) is strongly correlated with the amount of fuel consumed. By determining the future desulfurization time based on the fuel consumption used to determine the target desulfurization operation, the target desulfurization operation can be performed more promptly.

[0230] This application provides a post-processing apparatus. This post-processing apparatus is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "unit" can refer to a combination of software and / or hardware that performs a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0231] The aftertreatment device is installed on the vehicle and includes:

[0232] The target rich air-fuel ratio acquisition unit is used to acquire a target rich air-fuel ratio when switching from controlling the engine of the vehicle to controlling the engine to run in rich mode. The target rich air-fuel ratio is pre-calibrated and is used to reduce the fuel consumption of the engine when it runs in rich mode.

[0233] A control unit is used to control the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration, including: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

[0234] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by satisfying a first condition, the first condition including: the weight of nitrogen oxides adsorbed on LNTs during a target sub-period while controlling the engine to operate in lean-burn mode is greater than a nitrogen oxide adsorption weight threshold.

[0235] In one possible implementation, the switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by determining that a second condition is met during the period when the engine is operating in lean-burn mode. The second condition includes: the first average nitrogen oxide adsorption rate of LNTs determined during the period when the engine is controlled to operate in lean-burn mode is less than a first nitrogen oxide adsorption rate threshold.

[0236] In one possible implementation, the post-processing device further includes:

[0237] A first processing unit is configured to determine a second average nitrogen oxide adsorption rate of the LNT after controlling the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration; and to perform a first desulfurization operation when the second average nitrogen oxide adsorption rate is less than a second nitrogen oxide adsorption rate threshold. The first desulfurization operation includes controlling the temperature of the LNT to a temperature within a first desulfurization temperature range, and controlling the engine to operate in a lean-fuel mode at the target lean-fuel ratio for a first lean-fuel operation duration when the temperature of the LNT is within the first desulfurization temperature range.

[0238] In one possible implementation, the post-processing device further includes:

[0239] The second processing unit is used to determine the average adsorption rate of the third nitrogen oxides of the LNT after the first desulfurization operation is completed; when the average adsorption rate of the third nitrogen oxides is less than the third nitrogen oxide adsorption rate threshold, a second desulfurization operation is performed. The second desulfurization operation includes: controlling the temperature of the LNT to a temperature within the second desulfurization temperature range, and when the temperature of the LNT is within the second desulfurization temperature range, controlling the engine to operate in lean-burn mode for a second lean-burn duration, and controlling the engine to operate in rich-burn mode for a second rich-burn duration, wherein the second rich-burn duration is greater than the second lean-burn duration, and the ratio of the second lean-burn duration to the second rich-burn duration is a preset ratio.

[0240] In one possible implementation, the post-processing device further includes:

[0241] The third processing unit is used to determine the fourth average adsorption rate of nitrogen oxides of LNT after the second desulfurization operation is completed; when the fourth average adsorption rate of nitrogen oxides is less than the fourth nitrogen oxide adsorption rate threshold, the second desulfurization operation is performed again; after the second desulfurization operation is performed again, the fifth average adsorption rate of nitrogen oxides of LNT is determined; when the fifth average adsorption rate of nitrogen oxides is less than the fifth nitrogen oxide adsorption rate threshold, an alarm is triggered.

[0242] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes: a fourth processing unit configured to, after the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT, acquire a first exhaust back pressure of the GPF, and, in response to the first exhaust back pressure being greater than a lower exhaust back pressure threshold, perform a first GPF active regeneration operation, the first GPF active regeneration operation including: controlling the temperature of the GPF within a GPF active regeneration temperature range, and controlling the engine to operate at a target lean air-fuel ratio for a first active regeneration duration, wherein the magnitude of the first active regeneration duration is positively correlated with the magnitude of the GPF back pressure; and a third processing unit further configured to, in response to the completion of the first GPF active regeneration operation, determine the fourth average nitrogen oxide adsorption rate of the LNT.

[0243] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes: a fifth processing unit for acquiring a first exhaust back pressure of the GPF after the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT; and a third processing unit for determining the fourth average nitrogen oxide adsorption rate of the LNT in response to the first exhaust back pressure not being greater than an exhaust back pressure lower limit threshold.

[0244] In one possible implementation, the post-processing device further includes:

[0245] The sixth processing unit is used to acquire the vehicle's fuel consumption and determine the sulfur content corresponding to the fuel consumption; determine whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount; when it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount, perform a second desulfurization operation; after the second desulfurization operation is completed, when the vehicle is equipped with a particulate filter (GPF), acquire the second exhaust back pressure of the GPF; when the second exhaust back pressure is greater than the lower limit threshold of the exhaust back pressure, perform a first GPF active regeneration operation, the first GPF active regeneration operation including: controlling the temperature of the GPF within the GPF active regeneration temperature range, and controlling the engine to operate at a target lean air-fuel ratio for a first active regeneration duration.

[0246] In one possible implementation, the vehicle is equipped with a particulate filter (GPF), and the aftertreatment device further includes:

[0247] The seventh processing unit is used to acquire the third exhaust back pressure of the GPF; when the third exhaust back pressure is greater than the upper limit threshold of the exhaust back pressure, a second GPF active regeneration operation is executed, the second GPF active regeneration operation includes: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to run the second active regeneration for a target lean air-fuel ratio for a specified duration; after the second GPF active regeneration operation is completed, the fuel consumption of the vehicle after the most recent second desulfurization operation is acquired, and the sulfur content corresponding to the fuel consumption is determined; whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold of the cumulative amount is determined; when it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold of the cumulative amount, the second desulfurization operation is executed.

[0248] In one possible implementation, the post-processing device further includes:

[0249] The eighth processing unit is configured to, when receiving a shutdown command for the engine and meeting the supplementary rich-fuel conditions, control the engine to run in rich-fuel mode at the target rich-fuel air-fuel ratio for a first rich-fuel running time, and after completing the execution of controlling the engine to run in rich-fuel mode at the target rich-fuel air-fuel ratio for the first rich-fuel running time, control the engine to shut down.

[0250] In this embodiment, the device is presented in the form of a functional unit. Here, a unit refers to an ASIC circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above-mentioned functions.

[0251] Further functional descriptions of the above-mentioned units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0252] refer to Figure 9 This illustration shows a schematic diagram of a computer device on a vehicle for executing the post-processing method provided in this application, according to an embodiment of the present application. The computer device includes one or more processors 10, a memory 20, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components are interconnected via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system).

[0253] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0254] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0255] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0256] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0257] The computer device also includes an input device 30 and an output device 40. The processor 10, memory 20, input device 30, and output device 40 can be connected via a bus or other means.

[0258] Input device 30 can receive input numerical or character information, and generate key signal inputs related to user settings and function control of the computer device, such as a touchscreen, keypad, mouse, trackpad, touchpad, joystick, one or more mouse buttons, trackball, joystick, etc. Output device 40 may include display devices, auxiliary lighting devices (e.g., LEDs), and haptic feedback devices (e.g., vibration motors). The aforementioned display devices include, but are not limited to, liquid crystal displays, light-emitting diodes, displays, and plasma displays. In some alternative embodiments, the display device may be a touchscreen.

[0259] This application also provides a computer-readable storage medium. The methods described in this application can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods shown in the above embodiments are implemented.

[0260] A portion of the embodiments of this application can be applied as a computer program product, such as computer program instructions. When executed by a computer, these instructions, through the operation of the computer, can invoke or provide the methods and / or technical solutions according to the present invention. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Accordingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0261] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A post-processing method, characterized in that, Applied to vehicles equipped with lean nitrogen oxide capture catalyst (LNT), the method includes: When switching from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode, a target rich-burn air-fuel ratio is obtained, wherein the target rich-burn air-fuel ratio is pre-calibrated; Controlling the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration includes: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

2. The method according to claim 1, characterized in that, The switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by satisfying a first condition, which includes: the weight of nitrogen oxides adsorbed on LNTs during a target sub-period while controlling the engine to operate in lean-burn mode is greater than a nitrogen oxide adsorption weight threshold.

3. The method according to claim 1, characterized in that, The switch from controlling the vehicle's engine to operate in lean-burn mode to controlling the engine to operate in rich-burn mode is triggered by determining that a second condition is met during the period when the engine is operating in lean-burn mode. The second condition includes: the average adsorption rate of the first nitrogen oxides of LNTs is less than the first nitrogen oxide adsorption rate threshold determined during the period when the engine is controlled to operate in lean-burn mode.

4. The method according to claim 3, characterized in that, The method further includes: After controlling the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation period, the second average nitrogen oxide adsorption rate of LNT is determined. When the average adsorption rate of the second nitrogen oxide is less than the adsorption rate threshold of the second nitrogen oxide, a first desulfurization operation is performed. The first desulfurization operation includes: controlling the temperature of the LNT to a temperature within a first desulfurization temperature range, and when the temperature of the LNT is within the first desulfurization temperature range, controlling the engine to run in lean-burn mode with a target lean-burn air-fuel ratio for a first lean-burn running time.

5. The method according to claim 4, characterized in that, The method further includes: After the first desulfurization operation is completed, the average adsorption rate of the third nitrogen oxides of the LNT is determined; When the average adsorption rate of the third nitrogen oxide is less than the adsorption rate threshold of the third nitrogen oxide, a second desulfurization operation is performed. The second desulfurization operation includes: controlling the temperature of the LNT to a temperature within the second desulfurization temperature range, and when the temperature of the LNT is within the second desulfurization temperature range, controlling the engine to operate in lean-burn mode for a second lean-burn duration, and controlling the engine to operate in rich-burn mode for a second rich-burn duration, wherein the second rich-burn duration is greater than the second lean-burn duration, and the ratio of the second lean-burn duration to the second rich-burn duration is a preset ratio.

6. The method according to claim 5, characterized in that, The method further includes: After the second desulfurization operation is completed, the average adsorption rate of the fourth nitrogen oxides of the LNT is determined; When the average adsorption rate of the fourth nitrogen oxide is less than the adsorption rate threshold of the fourth nitrogen oxide, the second desulfurization operation is performed again. After the second desulfurization operation was completed, the average adsorption rate of nitrogen oxides of LNT was determined. An alarm is triggered when the average adsorption rate of the fifth nitrogen oxide is less than the adsorption rate threshold of the fifth nitrogen oxide.

7. The method according to claim 6, characterized in that, The vehicle is equipped with a particulate filter (GPF), and the method further includes: After the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT, the first exhaust back pressure of the GPF is obtained, and in response to the first exhaust back pressure being greater than the exhaust back pressure lower limit threshold, a first GPF active regeneration operation is performed. The first GPF active regeneration operation includes: controlling the temperature of the GPF within the GPF active regeneration temperature range, and controlling the engine to operate at a target lean-burn air-fuel ratio for a first active regeneration duration, wherein the magnitude of the first active regeneration duration is positively correlated with the magnitude of the GPF back pressure; and determining the fourth average nitrogen oxide adsorption rate of the LNT includes: In response to the completion of the first GPF active regeneration operation, the average adsorption rate of the fourth nitrogen oxides of the LNT is determined.

8. The method according to claim 6, characterized in that, The vehicle is equipped with a particulate filter (GPF), and the method further includes: After the second desulfurization operation is completed and before determining the fourth average nitrogen oxide adsorption rate of the LNT, the first exhaust back pressure of the GPF is obtained; and determining the fourth average nitrogen oxide adsorption rate of the LNT includes: In response to the first exhaust back pressure not being greater than the lower limit threshold of exhaust back pressure, the fourth average adsorption rate of nitrogen oxides of the LNT is determined.

9. The method according to claim 1, characterized in that, The method further includes: Obtain the fuel consumption of the vehicle and determine the sulfur content corresponding to the fuel consumption; Determine whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative amount; When it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the upper limit threshold of the cumulative content, the second desulfurization operation is performed; After the second desulfurization operation is completed, when the vehicle is equipped with a particulate filter (GPF), the second exhaust back pressure of the GPF is obtained. When the second exhaust back pressure is greater than the lower limit threshold of the exhaust back pressure, the first GPF active regeneration operation is performed. The first GPF active regeneration operation includes: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to run the first active regeneration for a target lean air-fuel ratio.

10. The method according to claim 1, characterized in that, The vehicle is equipped with a particulate filter (GPF), and the method further includes: Obtain the third exhaust back pressure of the GPF; When the third exhaust back pressure is greater than the upper limit threshold of the exhaust back pressure, the second GPF active regeneration operation is performed. The second GPF active regeneration operation includes: controlling the temperature of the GPF within the active regeneration temperature range of the GPF, and controlling the engine to run the second active regeneration for a target lean air-fuel ratio for a certain duration. After the second GPF active regeneration operation is completed, the fuel consumption of the vehicle after the most recent second desulfurization operation is obtained, and the sulfur content corresponding to the fuel consumption is determined. Determine whether the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower threshold of the cumulative amount; When it is determined that the cumulative sulfur content on the LNT corresponding to the sulfur content is greater than the lower limit threshold of the cumulative content, the second desulfurization operation is performed.

11. The method according to claim 1, characterized in that, The method further includes: When a shutdown command is received for the engine and the conditions for supplemental rich fuel are met, the engine is controlled to run in rich fuel mode with the target rich fuel air-fuel ratio for a first rich fuel running time. After the execution of controlling the engine to run in rich fuel mode with the target rich fuel air-fuel ratio for the first rich fuel running time is completed, the engine is controlled to shut down.

12. A post-processing apparatus, characterized in that, Installed on a vehicle, the device includes: A target rich air-fuel ratio acquisition unit is used to acquire a target rich air-fuel ratio when switching from controlling the engine of the vehicle to controlling the engine to run in a rich air-fuel mode, wherein the target rich air-fuel ratio is pre-calibrated. A control unit is used to control the engine to operate in a rich-fuel mode at the target rich-fuel ratio for a first rich-fuel operation duration, including: controlling the air-fuel ratio of the engine to the target rich-fuel ratio.

13. A vehicle, characterized in that, include: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method of any one of claims 1 to 11.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to perform the method of any one of claims 1 to 11.

15. A computer program product, characterized in that, Includes computer instructions for causing a computer to perform the method of any one of claims 1 to 11.

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