Control method and device for reducing HC leakage during diesel engine on-road regeneration

Abstract

The application provides a control method and device for reducing HC leakage in the driving regeneration process of a diesel engine. The method comprises the following steps: determining a smoke limit fuel quantity based on the intake flow at the current time and the excess air coefficient of the smoke limit; determining a transient correction factor based on the engine cycle fuel supply quantity and the smoke limit fuel quantity; the transient correction factor is used to reflect the transient degree and is negatively correlated with the transient degree; the smoke limit fuel quantity is positively correlated with the transient correction factor; determining a post-injection limit fuel quantity based on the transient correction factor and the engine speed at the current time; the post-injection limit fuel quantity is positively correlated with the transient correction factor and is negatively correlated with the engine speed; determining the post-injection fuel quantity after fuel limiting based on the carbon load at the current time, the exhaust flow at the current time, the DOC upstream temperature at the current time, the post-injection limit fuel quantity and the post-injection fuel quantity before fuel limiting. The post-injection fuel quantity is adjusted in time, so that the HC leakage after the DOC can be reduced in time.

Description

Technical Field

[0001] This invention relates to the field of diesel engine technology, and in particular to a control method and apparatus for reducing HC leakage during the regeneration process of a diesel engine. Background Technology

[0002] During diesel engine regeneration, the oxygen concentration drops momentarily due to a sudden increase in load, reducing the diesel oxidation catalyst's (DOC) ability to oxidize hydrocarbons (HC). This momentary drop in DOC leads to higher HC leakage. Higher levels of unburned HC during regeneration result in higher localized temperatures in the diesel particulate filter (DPF), affecting aftertreatment reliability and overall vehicle fuel consumption.

[0003] Existing technology involves real-time acquisition of the oxygen concentration in the vehicle's exhaust pipe. When the oxygen concentration falls below a preset threshold, the exhaust gas mass flow rate is obtained, and the oxygen mass flow rate is calculated based on the oxygen concentration and exhaust gas mass flow rate. Then, the theoretical regenerative fuel injection quantity corresponding to the current vehicle is calculated based on the calculated oxygen mass flow rate, and the smaller of this and the calculated regenerative fuel injection quantity is used to limit the regenerative fuel injection quantity. However, limiting the subsequent fuel injection quantity based on oxygen concentration has limitations. Due to the delay in the oxygen concentration signal, the calculated subsequent fuel injection quantity limitation occurs slightly later, resulting in limited effectiveness in reducing DOC and HC peak values.

[0004] Therefore, existing technologies make it difficult to adjust the post-injection fuel quantity in a timely manner, thus making it difficult to reduce the peak HC after DOC in a timely manner. Summary of the Invention

[0005] This invention provides a control method and apparatus for reducing HC leakage during the regeneration process of a diesel engine, thereby enabling timely adjustment of the fuel injection quantity and timely reduction of the HC peak value after DOC.

[0006] This invention provides a control method for reducing HC leakage during the regeneration process of a diesel engine, comprising: determining a smoke-limiting fuel quantity based on the current intake air flow and the smoke-limiting excess air coefficient; the smoke-limiting fuel quantity is used to correct the post-injection limiting fuel quantity under transient conditions; the smoke-limiting fuel quantity is positively correlated with the intake air flow and negatively correlated with the smoke-limiting excess air coefficient; determining a transient correction factor based on the engine cycle fuel supply and the smoke-limiting fuel quantity; the transient correction factor is used to reflect the transient degree and is negatively correlated with the transient degree; the smoke-limiting fuel quantity is positively correlated with the transient correction factor; determining a post-injection limiting fuel quantity based on the transient correction factor and the current engine speed; the post-injection limiting fuel quantity is positively correlated with the transient correction factor and negatively correlated with the engine speed; and determining the post-injection fuel quantity after fuel limiting based on the current carbon load, the current exhaust gas flow, the current DOC upstream temperature, the post-injection limiting fuel quantity, and the fuel injection quantities before and after fuel limiting.

[0007] In one embodiment, determining the smoke-limited fuel quantity based on the current airflow rate and the smoke-limited excess air coefficient includes: calculating the product of the current airflow rate and a preset weight, and determining the smoke-limited fuel quantity based on the ratio of the product to the smoke-limited excess air coefficient.

[0008] In one embodiment, determining the transient correction factor based on the engine cyclic fuel supply and the smoke-limited fuel supply includes: calculating the difference between the smoke-limited fuel supply and the engine cyclic fuel supply, and calculating the ratio of the difference to the engine cyclic fuel supply, and determining the ratio as the transient correction factor.

[0009] In one embodiment, determining the post-injection limited fuel quantity based on the transient correction factor and the current engine speed includes: determining the post-injection limited fuel quantity based on the transient correction factor, the current engine speed, and a first mapping table; wherein the first mapping table is a mapping table between the transient correction factor, the engine speed, and the post-injection limited fuel quantity.

[0010] In one embodiment, determining the post-limited fuel injection amount based on the current carbon load, current exhaust gas flow rate, current DOC upstream temperature, post-injection limited fuel amount, and fuel injection amounts before and after fuel limitation includes: obtaining the corresponding carbon load correction coefficient by looking up a table based on the current carbon load; determining the exhaust gas temperature correction coefficient based on the current exhaust gas flow rate, current DOC upstream temperature, and a second mapping table; wherein, in the second mapping table, the exhaust gas flow rate is negatively correlated with the exhaust gas temperature correction coefficient, and the DOC upstream temperature is positively correlated with the exhaust gas temperature correction coefficient; determining candidate post-limited fuel injection amounts based on the carbon load correction coefficient, the exhaust gas temperature correction coefficient, and the post-injection limited fuel amount; and determining the post-limited fuel injection amount based on the minimum of the candidate post-limited fuel injection amounts and the fuel injection amounts before and after fuel limitation.

[0011] In one embodiment, before determining the smoke-limiting oil quantity based on the current intake airflow and smoke-limiting excess air coefficient, the method further includes:

[0012] Based on the current intake airflow, the current engine speed, and the third mapping table, the smoke opacity limiting excess air coefficient is determined; the smoke opacity limiting excess air coefficient in the third mapping table is positively correlated with the intake airflow and negatively correlated with the engine speed.

[0013] In one embodiment, after determining the transient correction factor, the method further includes: opening the TV valve at a target opening speed when it is determined that the transient correction factor is less than a preset threshold and the vehicle is in a driving regeneration mode; the target opening speed is greater than the normal opening speed of the TV valve; or, opening the TV valve at the normal opening speed of the TV valve when it is determined that the transient correction factor is greater than or equal to the preset threshold.

[0014] The present invention also provides a control device for reducing HC leakage during the regeneration process of a diesel engine, comprising: a first determining module, used to determine the smoke opacity limiting fuel quantity based on the intake air flow and the smoke opacity limiting excess air coefficient at the current moment; the smoke opacity limiting fuel quantity is used to correct the post-injection limiting fuel quantity under transient conditions; the smoke opacity limiting fuel quantity is positively correlated with the intake air flow and negatively correlated with the smoke opacity limiting excess air coefficient; a second determining module, used to determine a transient correction factor based on the engine cycle fuel supply and the smoke opacity limiting fuel quantity; the transient correction factor is used to reflect the transient degree and is negatively correlated with the transient degree; the smoke opacity limiting fuel quantity is positively correlated with the transient correction factor; a third determining module, used to determine the post-injection limiting fuel quantity based on the transient correction factor and the engine speed at the current moment; the post-injection limiting fuel quantity is positively correlated with the transient correction factor and negatively correlated with the engine speed; a fourth determining module, used to determine the post-injection fuel quantity after fuel limiting based on the carbon load at the current moment, the exhaust gas flow at the current moment, the upstream temperature of DOC at the current moment, the post-injection limiting fuel quantity, and the fuel injection quantities before and after fuel limiting.

[0015] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the control method for reducing HC leakage during diesel engine regeneration as described above.

[0016] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for reducing HC leakage during diesel engine regeneration as described above.

[0017] The present invention provides a control method and apparatus for reducing HC leakage during diesel engine regeneration. It determines the smoke-limited fuel quantity by limiting the excess air coefficient based on intake air flow and smoke opacity. This allows for the subsequent determination of a transient correction factor based on the smoke-limited fuel quantity. This factor is used to correct the post-injection fuel quantity in cases of strong transients, thus preventing HC leakage caused by incomplete oxidation of DOC due to engine mis-air conditions. By adjusting the post-injection fuel quantity in a timely manner based on the transient correction factor, post-DOC HC leakage can be reduced promptly. Furthermore, considering the principle that engine speed and exhaust gas flow change significantly with stronger transients, the post-injection fuel quantity is further limited based on the current engine speed and exhaust gas flow, thereby reducing post-DOC HC leakage. In addition, by analyzing the factors contributing to HC leakage, the final post-injection fuel quantity after fuel limitation is determined by combining the current carbon load, the current upstream temperature of DOC, and the fuel quantities before and after fuel limitation, ensuring a more accurate post-injection fuel quantity without causing HC leakage. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is one of the flowcharts illustrating the control method for reducing HC leakage during diesel engine regeneration in operation, provided by the present invention.

[0020] Figure 2 This is the second flowchart of the control method for reducing HC leakage during diesel engine regeneration provided by the present invention;

[0021] Figure 3 This is a schematic diagram of the control framework of the TV valve provided by the present invention;

[0022] Figure 4 This is a schematic diagram of the framework for a control method to reduce HC leakage during the diesel engine regeneration process.

[0023] Figure 5 This is a schematic diagram of the control device for reducing HC leakage during the diesel engine regeneration process provided by the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] To facilitate understanding, the technical terms involved in this invention will first be explained.

[0026] Regeneration during driving: An active regeneration method triggered during vehicle operation. Regeneration during driving occurs when particulate matter accumulates to a certain level. When the vehicle meets the regeneration conditions (high load, high exhaust temperature) during driving, the DPF automatically enters the working state, injecting HC into the exhaust gas to increase the DPF temperature and burn off the carbon deposits inside the DPF.

[0027] DPF: The DPF is used to reduce particulate matter emissions from diesel engine exhaust. During the operation of the diesel particulate filter, particulate matter accumulates inside the filter, leading to increased exhaust back pressure. A DPF differential pressure sensor is typically used to monitor the pressure across the DPF to determine the amount of particulate matter captured. When the pressure difference across the DPF reaches a certain limit, it is considered that too many particles have been captured, triggering a regeneration request to oxidize the already captured particles and restore the DPF's ability to capture particles again.

[0028] Steady state: This can be understood as the engine operating under steady-state conditions, where the engine speed or thrust remains constant, such as when the engine is at idle or operating at a constant speed.

[0029] Transient: When an engine is in a transient operating state, it means that the engine speed or thrust is increasing or decreasing. Transient refers to acceleration, deceleration, starting and stopping.

[0030] Excess air coefficient: This refers to the ratio of the actual amount of air supplied for fuel combustion to the theoretical amount of air. It is an important parameter reflecting the fuel-air ratio and is commonly represented by the symbol "λ". In various furnaces or combustion chambers, to ensure the most complete combustion of fuel, the actual amount of air supplied must always be greater than the theoretical amount of air (the excess portion is called "excess air"), meaning the excess air coefficient must be greater than 1. However, combustion theory and operational experience show that λ that is too large or too small (indicating too much or too little air supply) is detrimental to combustion; that is, different combustion equipment has its own optimal excess air coefficient value.

[0031] TV valve: an intake throttle valve used to restrict air intake into the diesel engine, thereby increasing exhaust temperature and promoting the oxidation of particulate matter in the filter.

[0032] It is understandable that, due to limitations in existing technologies, it is difficult to adjust the post-injection quantity in a timely manner, thus hindering the timely reduction of the HC peak value after DOC. Therefore, this invention provides a control method for reducing HC leakage during the diesel engine regeneration process, which can adjust the post-injection quantity in a timely manner, thereby reducing the HC peak value after DOC.

[0033] The following description, in conjunction with the accompanying drawings, describes the control method and apparatus for reducing HC leakage during the regeneration process of a diesel engine.

[0034] Figure 1 This is a flowchart illustrating the control method for reducing HC leakage during the regeneration process of a diesel engine, as provided by the present invention. It is understood that the control method for reducing HC leakage during the regeneration process of a diesel engine can be applied to the field of diesel engines and can be executed by a control device for reducing HC leakage during the regeneration process of a diesel engine, such as... Figure 1 As shown, the method includes the following steps:

[0035] Step 110: Determine the smoke-limited oil quantity based on the current air intake flow rate and smoke-limited excess air coefficient.

[0036] The smoke opacity limiting fuel quantity is used to correct the fuel quantity after injection in transient conditions. The smoke opacity limiting fuel quantity is positively correlated with the intake air flow rate and negatively correlated with the smoke opacity limiting excess air coefficient. The smoke opacity limiting excess air coefficient can be understood as the excess air coefficient under transient conditions.

[0037] In one embodiment, step 110 includes: calculating the product of the current airflow rate and a preset weight, and determining the smoke-limiting oil quantity based on the ratio of the product to the smoke-limiting excess air coefficient. For example, the preset weight can be 14.5.

[0038] It is understood that the present invention only provides one possible example of the smoke limit oil quantity described above. In actual applications, the smoke limit oil quantity may also take other forms, and the present invention does not limit it.

[0039] It is understandable that under transient conditions, engine speed or thrust increases or decreases, the intake airflow is smaller compared to the steady-state intake airflow, and the smoke opacity limiting excess air coefficient is also smaller compared to the steady-state excess air coefficient. Furthermore, since the smoke opacity limiting fuel quantity is positively correlated with the intake airflow and negatively correlated with the smoke opacity limiting excess air coefficient, the smoke opacity limiting fuel quantity is smaller under transient conditions compared to the engine's cyclic fuel supply under steady-state conditions. Therefore, the degree of transientity can be judged by the magnitude of the cyclic fuel supply and the smoke opacity limiting fuel quantity.

[0040] Step 120: Determine the transient correction factor based on the engine's cyclic fuel supply and smoke-limited fuel quantity.

[0041] The engine cycle fuel supply quantity refers to the real-time fuel supply quantity of the engine, measured in mg / cycle. The transient correction factor reflects the degree of transient response and is negatively correlated with it. The smoke-limiting fuel quantity is positively correlated with the transient correction factor.

[0042] In one embodiment, step 120 includes: calculating the difference between the smoke-limiting fuel quantity and the engine's cyclic fuel supply quantity, and calculating the ratio of the difference to the engine's cyclic fuel supply quantity, and determining the ratio as a transient correction factor. It is understood that this invention only provides one possible example of the smoke-limiting fuel quantity; in practical applications, the transient correction factor can also take other forms, and this invention does not limit its application.

[0043] It is understandable that, since the transient correction factor is negatively correlated with the transient severity, the smoke opacity-limited fuel quantity is positively correlated with the transient correction factor; therefore, the smoke opacity-limited fuel quantity is negatively correlated with the transient severity. In other words, the smaller the smoke opacity-limited fuel quantity, the smaller the transient correction factor and the greater the transient severity; conversely, the larger the smoke opacity-limited fuel quantity, the larger the transient correction factor and the smaller the transient severity. Limiting fuel quantity in post-injection based on the transient severity, starting when the oxygen concentration begins to decrease, results in more timely fuel limiting and a significant reduction in HC after DOC reduction.

[0044] Step 130: Determine the post-injection limited fuel quantity based on the transient correction factor and the current engine speed.

[0045] The amount of fuel injected after the engine is restricted is positively correlated with the transient correction factor and negatively correlated with the engine speed.

[0046] Specifically, a mapping table between the post-injection limited fuel quantity, the transient correction factor, and the engine speed can be pre-calibrated so that the post-injection limited fuel quantity corresponding to the transient correction factor and the engine speed at the current moment can be determined through the mapping table.

[0047] Therefore, in one embodiment, step 130 includes: determining the post-injection limited fuel quantity based on the transient correction factor, the current engine speed, and a first mapping table. The first mapping table is a mapping table between the transient correction factor, engine speed, and post-injection limited fuel quantity.

[0048] As can be understood from step 120 above, a smaller transient correction factor indicates a stronger transient state, and consequently, a smaller post-injection fuel quantity limit. The post-injection fuel quantity limit is positively correlated with the transient correction factor. A stronger transient state results in lower oxygen concentration in the exhaust pipe, higher engine speed, and a larger exhaust gas flow rate, leading to poorer DOC oxidation capacity. Therefore, the post-injection fuel quantity can be further limited based on the current engine speed to reduce DOC-related HC leakage. Thus, the corresponding post-injection fuel quantity limit can be determined based on the current engine speed and the transient correction factor. This allows for adjustment of the post-injection fuel quantity limit in transient situations, based on the transient correction factor, thereby limiting fuel injection according to the transient state. Fuel limitation begins when the oxygen concentration starts to decrease, resulting in more timely fuel limitation and a significant reduction in DOC-related HC leakage. It can be understood that a stronger transient state indicates an engine under-gas condition, where the post-injection fuel cannot be completely oxidized by DOC. In this case, timely limitation of the post-injection fuel quantity reduces DOC-related HC leakage.

[0049] Step 140: Based on the current carbon load, current exhaust gas flow rate, current DOC upstream temperature, post-injection limited fuel quantity, and fuel injection quantities before and after fuel limitation, determine the post-injection fuel quantity after fuel limitation.

[0050] It is understandable that the stronger the transient response, the lower the oxygen concentration in the exhaust pipe, and the higher the engine speed, indicating a larger exhaust gas flow and poorer DOC oxidation capacity. Therefore, the subsequent fuel injection quantity can be further limited based on the current exhaust gas flow to reduce HC leakage after DOC. Furthermore, the fuel injection quantity is corrected based on carbon load because a higher carbon load results in a lower fuel injection quantity and a lower risk of HC leakage; therefore, no correction is needed to increase the regeneration temperature. Similarly, the fuel injection quantity is corrected based on exhaust gas flow and upstream DOC temperature because HC leakage is also lower at higher DOC temperatures or lower exhaust gas flow rates; therefore, no correction is needed to increase the regeneration temperature. Correcting the subsequent fuel injection quantity based on carbon load, upstream DOC temperature, and exhaust gas flow reduces unnecessary fuel limitation and increases the regeneration temperature.

[0051] The present invention provides a control method for reducing HC leakage during diesel engine regeneration. It determines the smoke-limited fuel quantity by limiting the excess air coefficient based on intake air flow and smoke opacity. This allows for the subsequent determination of a transient correction factor based on the smoke-limited fuel quantity. This factor is used to adjust the post-injection fuel quantity in cases of strong transients, thus preventing HC leakage caused by incomplete oxidation of the DOC (dioxide, carbon dioxide, and oxygen) in the post-injection fuel when the engine is in a short-gas state. By adjusting the post-injection fuel quantity in a timely manner based on the transient correction factor, post-DOC HC leakage can be reduced promptly. Furthermore, considering the principle that engine speed and exhaust gas flow change significantly with stronger transients, the post-injection fuel quantity is further limited based on the current engine speed and exhaust gas flow, thereby reducing post-DOC HC leakage. In addition, by analyzing the factors contributing to HC leakage, the final post-injection fuel quantity after fuel limitation is determined by combining the current carbon load, the current upstream temperature of the DOC, and the fuel quantities before and after fuel limitation, ensuring a more accurate post-injection fuel quantity without causing HC leakage.

[0052] In one embodiment, such as Figure 2 As shown, step 140 above includes:

[0053] Step 210: Based on the carbon loading at the current moment, look up the corresponding carbon loading correction coefficient in the table.

[0054] As mentioned earlier, the fuel injection quantity is corrected based on carbon load because the fuel injection quantity is lower after a high carbon load, and the risk of HC leakage is lower. In order to increase the regeneration temperature, no correction is required.

[0055] Step 220: Determine the exhaust gas temperature correction coefficient based on the current exhaust gas flow rate, the current DOC upstream temperature, and the second mapping table.

[0056] In the second mapping table, the exhaust gas flow rate is negatively correlated with the exhaust gas temperature correction coefficient, while the upstream temperature of DOC is positively correlated with the exhaust gas temperature correction coefficient.

[0057] It is understandable that the stronger the transient response, the lower the oxygen concentration in the exhaust pipe, and the higher the engine speed, indicating a larger exhaust gas flow and a poorer DOC oxidation capacity. Therefore, the fuel injection quantity can be further limited based on the current exhaust gas flow to reduce HC leakage after DOC. The fuel injection quantity is corrected based on exhaust gas flow and upstream DOC temperature because HC leakage is also lower at higher DOC temperatures or lower exhaust gas flow rates; therefore, no correction is necessary to increase the regeneration temperature.

[0058] Therefore, specifically, a mapping table of exhaust gas flow rate, upstream DOC temperature and exhaust gas temperature correction coefficient can be determined in advance based on bench tests, which will facilitate the subsequent correction of fuel injection quantity based on exhaust gas flow rate and upstream DOC temperature.

[0059] Step 230: Based on the carbon load correction coefficient, the exhaust gas temperature correction coefficient, and the post-injection limited fuel quantity, determine the candidate post-injection fuel quantity after fuel limitation.

[0060] Specifically, the amount of fuel injected after limiting fuel injection can be determined based on the product of the carbon load correction coefficient, the exhaust gas temperature correction coefficient, and the amount of fuel injected after limiting fuel injection.

[0061] Step 240: Determine the fuel injection amount after fuel limitation based on the minimum of the candidate fuel injection amount after fuel limitation and the fuel injection amount before and after fuel limitation.

[0062] It is understandable that taking the minimum value from the fuel injection amount before and after fuel restriction and the determined candidate fuel injection amount after fuel restriction as the fuel injection amount after fuel restriction can reduce HC leakage after DOC.

[0063] In one embodiment, prior to step 110 above, the method further includes: determining the smoke limit excess air coefficient based on the current intake air flow rate, the current engine speed, and a third mapping table.

[0064] In the third mapping table, the smoke limit excess air coefficient is positively correlated with the intake airflow and negatively correlated with the engine speed.

[0065] As mentioned earlier, the smoke opacity excess air coefficient can be understood as the excess air coefficient under transient conditions. It can be understood that the smoke opacity excess air coefficient can be a calibration value, obtained based on smoke opacity and acceleration time. Since smoke opacity and acceleration time cannot be practically calibrated, the corresponding smoke opacity excess air coefficient is usually calibrated by running a load step on a test bench to the corresponding intake airflow and engine speed, resulting in a mapping table of the corresponding smoke opacity excess air coefficient. In other words, the third mapping table corresponding to the smoke opacity excess air coefficient is obtained based on the intake airflow and engine speed during the load step operation. Then, according to the corresponding first mapping table, the corresponding smoke opacity excess air coefficient at the current intake airflow and current engine speed can be determined.

[0066] It can also be understood that the calibrated excess air coefficient for smoke opacity limitation can be interpreted as the excess air coefficient under transient conditions. It is inversely proportional to the intake airflow and directly proportional to the engine speed, and is smaller compared to the excess air coefficient under steady-state conditions. When the engine is in a transient state, the greater the smoke opacity (the smaller the intake airflow), the larger the excess air coefficient for smoke opacity limitation; conversely, the smaller the acceleration (the smaller the engine speed), the smaller the excess air coefficient for smoke opacity limitation. The stronger the transient state (greater smoke opacity and greater acceleration), the larger the excess air coefficient for smoke opacity limitation. Furthermore, under transient conditions, the excess air coefficient for smoke opacity limitation is lower than the engine's excess air coefficient under steady-state conditions.

[0067] In one embodiment, after determining the transient correction factor, the method further includes: opening the TV valve at a target opening speed when it is determined that the transient correction factor is less than a preset threshold and the vehicle is in a driving regeneration mode; the target opening speed is greater than the normal opening speed of the TV valve; or, opening the TV valve at the normal opening speed of the TV valve when it is determined that the transient correction factor is greater than or equal to the preset threshold.

[0068] Among them, the minimum value corresponding to the hysteresis interval of the preset threshold transient correction factor.

[0069] It's understandable that, since the transient correction factor reflects the degree of transient change and is negatively correlated with it, a smaller transient correction factor indicates a stronger transient state. In the case of regeneration mode, this can accelerate the opening speed of the TV valve. The stronger the transient state, the greater the smoke and acceleration, and the engine is in a state of oxygen shortage. Therefore, to increase the aftertreatment oxygen concentration at the moment of load increase, the TV valve opening speed is accelerated during regeneration (when the load increases, the TV valve opening degree increases with the increase in circulating fuel supply; however, due to the limitation of circulating fuel supply by smoke and fuel quantity during load increase, the TV valve opening speed is relatively slow). Increasing the TV valve opening speed effectively improves the aftertreatment oxygen concentration when it is low.

[0070] Specifically, the control of the TV valve can be referred to Figure 3 The diagram shows a frame. Figure 3 As shown, facCurrmax and facCurrmin are the maximum and minimum values ​​of the hysteresis interval of the transient correction factor, respectively. When the transient correction factor is lower than facCurrmin and the system is in regeneration mode, the TV valve opening speed is the TV valve fast opening speed (target opening speed); otherwise, the TV valve normal opening speed is executed. The TV valve fast opening speed can be calibrated based on the transient correction factor.

[0071] Figure 4 This is a schematic diagram illustrating the framework of the control method for reducing HC leakage during the diesel engine regeneration process provided by the present invention. Figure 4 As shown, firstly, the difference between the smoke-limited fuel quantity and the engine's cyclic fuel supply quantity is calculated, and the ratio of this difference to the engine's cyclic fuel supply quantity is determined as a transient correction factor. Then, based on the transient correction factor and engine speed, a first mapping table is consulted to obtain the corresponding post-injection limited fuel quantity. In addition, the corresponding carbon load correction coefficient can be obtained by looking up a table based on the current carbon load. Based on the current exhaust gas flow rate, the current DOC upstream temperature, and a second mapping table, an exhaust gas temperature correction coefficient is determined. Based on the product of the carbon load correction coefficient, the exhaust gas temperature correction coefficient, and the post-injection limited fuel quantity, a candidate post-limited fuel injection quantity is determined. Based on the minimum of the candidate post-limited fuel injection quantity and the fuel injection quantities before and after fuel limitation, the post-limited fuel injection quantity is determined.

[0072] The control device for reducing HC leakage during diesel engine regeneration process provided by the present invention is described below.

[0073] Figure 5 This is a schematic diagram of the control device for reducing HC leakage during the diesel engine regeneration process provided by the present invention, as shown below. Figure 5 As shown, the control device for reducing HC leakage during the regeneration process of a diesel engine provided by the present invention includes: a first determining module 510, used to determine the smoke limiting fuel quantity based on the intake air flow and the smoke limiting excess air coefficient at the current moment; the smoke limiting fuel quantity is used to correct the injection limiting fuel quantity under transient conditions; the smoke limiting fuel quantity is positively correlated with the intake air flow and negatively correlated with the smoke limiting excess air coefficient;

[0074] The second determining module 520 is used to determine a transient correction factor based on the engine's cyclic fuel supply and the smoke-limiting fuel quantity; the transient correction factor is used to reflect the transient degree and is negatively correlated with the transient degree; the smoke-limiting fuel quantity is positively correlated with the transient correction factor;

[0075] The third determining module 530 is used to determine the post-injection limited fuel quantity based on the transient correction factor and the engine speed at the current moment; the post-injection limited fuel quantity is positively correlated with the transient correction factor and negatively correlated with the engine speed;

[0076] The fourth determining module 540 is used to determine the amount of fuel injected after fuel limitation based on the carbon load at the current time, the exhaust gas flow rate at the current time, the upstream temperature of DOC at the current time, the fuel injection limitation amount, and the fuel injection amount before and after fuel limitation.

[0077] The control device for reducing HC leakage during diesel engine regeneration provided by this invention determines the smoke-limited fuel quantity by limiting the excess air coefficient based on intake air flow and smoke opacity. This allows for the subsequent determination of a transient correction factor based on the smoke-limited fuel quantity. This factor is used to adjust the post-injection fuel quantity in cases of strong transients, thus preventing HC leakage caused by incomplete oxidation of DOC due to engine mis-air conditions. By adjusting the post-injection fuel quantity in a timely manner based on the transient correction factor, post-DOC HC leakage can be reduced promptly. Furthermore, considering the principle that engine speed and exhaust gas flow change significantly with stronger transients, the device further limits the post-injection fuel quantity based on the current engine speed and exhaust gas flow, thereby reducing post-DOC HC leakage. In addition, by analyzing the factors contributing to HC leakage, the device also combines the current carbon load, the current upstream temperature of DOC, and the fuel quantities before and after fuel limiting to determine the final post-injection fuel quantity after fuel limiting, ensuring a more accurate post-injection fuel quantity without causing HC leakage.

[0078] In one embodiment, a computer device is provided, the computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the following steps corresponding to a control method for reducing HC leakage during diesel engine regeneration: determining a smoke-limiting fuel quantity based on the current intake air flow rate and the smoke-limiting excess air coefficient; the smoke-limiting fuel quantity is used to correct the post-injection limiting fuel quantity under transient conditions; the smoke-limiting fuel quantity is positively correlated with the intake air flow rate and negatively correlated with the smoke-limiting excess air coefficient. Based on the engine's cyclic fuel supply and smoke-limited fuel quantity, a transient correction factor is determined; the transient correction factor reflects the degree of transientity and is negatively correlated with the degree of transientity; the smoke-limited fuel quantity is positively correlated with the transient correction factor; based on the transient correction factor and the engine speed at the current moment, the post-injection limited fuel quantity is determined; the post-injection limited fuel quantity is positively correlated with the transient correction factor and negatively correlated with the engine speed; based on the carbon load at the current moment, the exhaust gas flow rate at the current moment, the upstream temperature of DOC at the current moment, the post-injection limited fuel quantity, and the fuel injection quantities before and after fuel limitation, the post-injection quantity after fuel limitation is determined.

[0079] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the control method for reducing HC leakage during the regeneration process of a diesel engine provided by the present invention, the method comprising: determining a smoke-limiting fuel quantity based on the current intake air flow and the smoke-limiting excess air coefficient; the smoke-limiting fuel quantity being used to correct the post-injection limiting fuel quantity under transient conditions; the smoke-limiting fuel quantity being positively correlated with the intake air flow and positively correlated with the smoke-limiting excess air coefficient. The air volume coefficient is negatively correlated; a transient correction factor is determined based on the engine's cyclic fuel supply and smoke-limited fuel quantity; the transient correction factor reflects the transient degree and is negatively correlated with the transient degree; the smoke-limited fuel quantity is positively correlated with the transient correction factor; the post-injection limited fuel quantity is determined based on the transient correction factor and the engine speed at the current moment; the post-injection limited fuel quantity is positively correlated with the transient correction factor and negatively correlated with the engine speed; the post-injection fuel quantity after fuel limitation is determined based on the carbon load at the current moment, the exhaust gas flow rate at the current moment, the upstream temperature of DOC at the current moment, the post-injection limited fuel quantity, and the fuel injection quantities before and after fuel limitation.

[0080] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the control method for reducing HC leakage during the regeneration process of a diesel engine provided by the present invention. The method includes: determining a smoke-limiting fuel quantity based on the current intake air flow rate and the smoke-limiting excess air coefficient; the smoke-limiting fuel quantity is used to correct the post-injection limiting fuel quantity under transient conditions; the smoke-limiting fuel quantity is positively correlated with the intake air flow rate and negatively correlated with the smoke-limiting excess air coefficient; and based on the engine's cyclic fuel supply... The amount of fuel injected is limited based on the amount of smoke and the amount of fuel injected, and a transient correction factor is determined. The transient correction factor reflects the degree of transientity and is negatively correlated with the degree of transientity. The amount of fuel injected to limit the amount of smoke is positively correlated with the transient correction factor. Based on the transient correction factor and the engine speed at the current moment, the amount of fuel injected to limit the amount of fuel injected after fuel limitation is determined. The amount of fuel injected to limit the amount of fuel injected after fuel limitation is determined based on the carbon load at the current moment, the exhaust gas flow rate at the current moment, the upstream temperature of DOC at the current moment, the amount of fuel injected to limit the amount of fuel injected after fuel limitation, and the amount of fuel injected before and after fuel limitation.

[0081] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0082] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0083] It is understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for reducing HC leakage during diesel engine regeneration, characterized in that, include: Based on the current intake airflow and smoke opacity limiting excess air coefficient, the smoke opacity limiting fuel quantity is determined; the smoke opacity limiting fuel quantity is used to correct the limited fuel quantity in transient situations; the smoke opacity limiting fuel quantity is positively correlated with the intake airflow and negatively correlated with the smoke opacity limiting excess air coefficient. Based on the engine's cyclic fuel supply and smoke-limited fuel quantity, the transient correction factor is determined; The transient correction factor is used to reflect the degree of transientity and is negatively correlated with the degree of transientity; The smoke limit oil quantity is positively correlated with the transient correction factor; Based on the transient correction factor and the current engine speed, determine the post-injection limited fuel quantity; The amount of fuel injected after the engine is limited is positively correlated with the transient correction factor and negatively correlated with the engine speed. Based on the current carbon load, current exhaust gas flow rate, current DOC upstream temperature, post-injection limited fuel quantity, and fuel injection quantities before and after fuel limitation, determine the post-injection fuel quantity after fuel limitation. Before determining the smoke-limiting oil quantity based on the current intake airflow and smoke-limiting excess air coefficient, the method further includes: Based on the current intake airflow, the current engine speed, and the third mapping table, determine the smoke limit excess air coefficient; In the third mapping table, the smoke limit excess air coefficient is positively correlated with the intake airflow and negatively correlated with the engine speed.

2. The control method for reducing HC leakage during diesel engine regeneration as described in claim 1, characterized in that, The determination of the smoke-limiting oil quantity based on the current airflow rate and the smoke-limiting excess air coefficient includes: Calculate the product of the current intake airflow and the preset weight, and determine the smoke-limited oil quantity based on the ratio of the product to the smoke-limited excess air coefficient.

3. The control method for reducing HC leakage during diesel engine regeneration as described in claim 1, characterized in that, The determination of the transient correction factor based on the engine's cyclic fuel supply and smoke-limited fuel quantity includes: The difference between the smoke-limited fuel quantity and the engine's circulating fuel supply quantity is calculated, and the ratio of the difference to the engine's circulating fuel supply quantity is determined as the transient correction factor.

4. The control method for reducing HC leakage during diesel engine regeneration as described in claim 1, characterized in that, The determination of the post-injection limited fuel quantity based on the transient correction factor and the current engine speed includes: Based on the transient correction factor, the current engine speed, and the first mapping table, the post-injection limited fuel quantity is determined; The first mapping table is a mapping table between transient correction factor, engine speed and post-injection limited fuel quantity.

5. The control method for reducing HC leakage during diesel engine regeneration as described in claim 1, characterized in that, The determination of the post-injection quantity after fuel limitation, based on the current carbon load, current exhaust gas flow rate, current DOC upstream temperature, post-injection limited fuel quantity, and fuel injection quantities before and after fuel limitation, includes: The corresponding carbon loading correction factor is obtained by looking up the table based on the current carbon loading. Based on the current exhaust gas flow rate, the current DOC upstream temperature, and the second mapping table, the exhaust gas temperature correction coefficient is determined; wherein, in the second mapping table, the exhaust gas flow rate is negatively correlated with the exhaust gas temperature correction coefficient, and the DOC upstream temperature is positively correlated with the exhaust gas temperature correction coefficient. Based on the carbon load correction coefficient, the exhaust gas temperature correction coefficient, and the post-injection limited fuel quantity, the candidate post-injection fuel quantity after fuel limitation is determined; The fuel injection amount after fuel limitation is determined based on the minimum of the fuel injection amount after fuel limitation and the fuel injection amount before and after fuel limitation.

6. The control method for reducing HC leakage during diesel engine regeneration as described in claim 1, characterized in that, After determining the transient correction factor, the method further includes: If the transient correction factor is determined to be less than a preset threshold and the vehicle is in regenerative driving mode, the intake throttle valve is opened at a target opening speed; the target opening speed is greater than the normal opening speed of the intake throttle valve; or, If the transient correction factor is determined to be greater than or equal to a preset threshold, the intake throttle valve is opened at the normal opening speed of the intake throttle valve.

7. A control device for reducing HC leakage during diesel engine regeneration, characterized in that, include: The first determining module is used to determine the smoke opacity limiting fuel quantity based on the current air intake flow rate and the smoke opacity limiting excess air coefficient; the smoke opacity limiting fuel quantity is used to correct the limited fuel quantity after injection in transient situations; the smoke opacity limiting fuel quantity is positively correlated with the air intake flow rate and negatively correlated with the smoke opacity limiting excess air coefficient. The second determination module is used to determine the transient correction factor based on the engine's cyclic fuel supply and smoke-limited fuel quantity; The transient correction factor is used to reflect the degree of transientity and is negatively correlated with the degree of transientity; The smoke limit oil quantity is positively correlated with the transient correction factor; The third determining module is used to determine the post-injection limited fuel quantity based on the transient correction factor and the engine speed at the current moment; The amount of fuel injected after the engine is limited is positively correlated with the transient correction factor and negatively correlated with the engine speed. The fourth determination module is used to determine the amount of fuel injected after fuel limitation based on the current carbon load, the current exhaust gas flow rate, the current DOC upstream temperature, the fuel injection limitation amount, and the fuel injection amounts before and after fuel limitation. The device is also used for: Before determining the smoke limit fuel quantity based on the current intake air flow and smoke limit excess air coefficient, the smoke limit excess air coefficient is determined based on the current intake air flow, the current engine speed, and the third mapping table. In the third mapping table, the smoke limit excess air coefficient is positively correlated with the intake airflow and negatively correlated with the engine speed.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the control method for reducing HC leakage during diesel engine regeneration as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method for reducing HC leakage during diesel engine regeneration as described in any one of claims 1 to 6.

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