EGR cooler with changeable heat exchange structure and NOx control method of EGR cooler

Abstract

The invention discloses an EGR cooler with a variable heat exchange structure and a NOx control method of the EGR cooler, and belongs to the technical field of diesel engine emission control. The system comprises an EGR multi-source data acquisition module for determining a target vehicle as a data acquisition source, acquiring an exhaust gas temperature comprehensive data packet according to an inlet and outlet area of an EGR cooler, and acquiring an emission comprehensive data packet by sensors deployed in pipelines of the inlet and outlet areas of the EGR cooler; the actual cooling efficiency value of the waste air temperature comprehensive data packet is analyzed, and a fin heat exchange area adjusting pre-instruction is generated in combination with the real-time efficiency value of the engine; the NOx state analysis module monitors the actual flow resistance of an EGR channel in real time, when the flow resistance value exceeds a threshold value, a high priority signal for immediately stopping fin adjustment is generated, the situation that fin action aggravates channel blockage is prevented, and the risk that a cooler is scrapped due to coking is avoided in advance; after the intelligent optimization regulation and control module executes the fin action, the final voltage value and the fin state are fed back to the NOx control platform in real time.

Description

Technical Field

[0001] This invention relates to the field of diesel engine emission control technology, specifically to an EGR cooler with a variable thermal structure and its NOx control method. Background Technology

[0002] EGR coolers are a core component of the internal combustion engine emission control system. Their function is to cool part of the high-temperature exhaust gas and reintroduce it into the combustion chamber, thereby suppressing the formation of nitrogen oxides (NOx) by reducing the combustion temperature and optimizing combustion efficiency. Existing EGR coolers generally adopt a fixed cross-section channel design, combined with a traditional transverse fin structure to achieve heat exchange. They rely on a preset fixed heat exchange capacity to adapt to engine operating conditions. The core logic is to cool the exhaust gas through static structural parameters (such as fixed channel cross-sectional area and fixed fin shape), without dynamically adjusting for the heat exchange requirements under different operating conditions. Moreover, they mostly rely on a single temperature parameter to indirectly link NOx control, lacking a control mechanism that directly links with emission indicators.

[0003] Existing EGR coolers, under high temperature or high NOx emission conditions, cannot meet the enhanced cooling requirements due to their fixed heat exchange capacity. This results in insufficient exhaust gas cooling, and the increased intake air temperature exacerbates NOx formation in the cylinder, leading to excessive emissions. Traditional transverse fin structures have low heat exchange efficiency and high flow resistance, and lack a closed-loop control mechanism based on dynamic adjustment under operating conditions. This makes it difficult to strike a balance between anti-coking requirements and efficient cooling goals, and thus cannot adapt to the engine's full operating condition requirements.

[0004] To address the aforementioned technical shortcomings, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an EGR cooler with a changeable thermal structure and its NOx control method to solve the problems mentioned above.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a NOx control method for an EGR cooler with a changeable thermal structure, comprising a NOx control platform, wherein the NOx control platform is communicatively connected to an EGR multi-source data acquisition module, a temperature change data analysis module, a NOx status analysis module, and an intelligent optimization and control module.

[0007] The EGR multi-source data acquisition module identifies the target vehicle as the data acquisition source, acquires comprehensive exhaust gas temperature data based on the EGR cooler inlet and outlet areas, and acquires comprehensive emission data based on sensors deployed in the EGR cooler inlet and outlet pipes.

[0008] The temperature change data analysis module analyzes the actual cooling efficiency value of the exhaust gas temperature comprehensive data package and generates a pre-command for adjusting the fin heat exchange area by combining it with the engine's real-time efficiency value.

[0009] The NOx status analysis module generates NOx correction factors and flow resistance intervention judgment signals based on the pipe status of the EGR cooler pipes, as well as the joint analysis of exhaust gas flow resistance and exhaust gas concentration.

[0010] The intelligent optimization and control module integrates and analyzes the signal results obtained from multi-step joint judgment to finally obtain the execution command to control the fin movement and optimize the adjustment method.

[0011] Furthermore, the EGR multi-source data acquisition module determines the target vehicle as the data acquisition source, and first acquires the temperature of the exhaust gas passing through the EGR cooler inlet area according to the cycle node, and marks it as the initial temperature value of the EGR inlet exhaust gas, and marks the temperature at the corresponding position of the EGR cooler outlet pipe as the cooling temperature value of the EGR outlet exhaust gas, and summarizes and marks them as the exhaust gas temperature comprehensive data package.

[0012] Based on the NOx content in the exhaust gas after cooling treatment collected at the periodic nodes, it is marked as the real-time NOx concentration data value of the exhaust gas. The initial pressure data value at different locations in the channel is collected in real time. The obtained NOx concentration data value and initial pressure data value are summarized and marked as the comprehensive emission data package.

[0013] Furthermore, the temperature change data analysis module randomly selects the initial temperature value of the EGR inlet exhaust gas and the cooling temperature value of the EGR outlet exhaust gas at one of the cycle nodes. By analyzing the difference between the initial temperature value of the EGR inlet exhaust gas and the cooling temperature value of the EGR outlet exhaust gas, it marks this as the cooling difference. It also obtains the difference by comparing it with the initial temperature value of the EGR inlet exhaust gas based on the factory-preset cooling medium temperature threshold on the EGR cooler label. This difference is marked as the cooler difference. Finally, the actual cooling efficiency value of the EGR cooler corresponding to the current cycle node is obtained by dividing the cooling difference by the cooler difference.

[0014] Furthermore, based on the NOx control platform and the ECU module of the target vehicle system, the engine real-time efficiency value and speed comparison threshold are obtained. The actual cooling efficiency value and the engine real-time efficiency value are compared and analyzed with the cooling efficiency threshold and the speed comparison threshold. If the engine real-time efficiency value is not within the range of the speed comparison threshold and the actual cooling efficiency value is less than the cooling efficiency threshold, an invalid data signal is generated. If the engine real-time efficiency value is within the range of the speed comparison threshold and the actual cooling efficiency value is greater than or equal to the cooling efficiency threshold, a log is generated.

[0015] Furthermore, by comparing the actual cooling efficiency value recorded in the log with the real-time engine efficiency value, and comparing them with the basic cooling fin voltage mapping table, the cooling efficiency value and the initial voltage value corresponding to the engine speed that are closest to the actual cooling efficiency value and the real-time engine efficiency value in the basic cooling fin voltage mapping table are selected and marked as the basic fin adjustment voltage reference value. At the same time, the state ratio between the initial temperature value of the EGR inlet exhaust gas and the exhaust gas temperature threshold is judged: if the result is determined to be a low temperature condition, a pre-command for partial fin contraction and wall adhesion is generated; if the result is determined to be a high temperature condition, a pre-command for the fins to fully expand and branch out is generated.

[0016] Furthermore, the NOx status analysis module marks the recorded data generated by the inlet and outlet areas of the EGR cooler as static inlet data P1 and static outlet data P2, respectively, within all data covered by the selected periodic nodes, and obtains the pressure difference using a formula. Based on the real-time exhaust gas flow data of the EGR cooler inlet area, the standard flow rate is obtained by processing according to the formula. The flow area of ​​the EGR cooler pipe, which is a circular channel, is obtained through formula analysis. The actual flow resistance R of the EGR channel is obtained by jointly comparing the standard flow rate, flow area, and pressure difference.

[0017] Furthermore, based on the NOx control platform, the EGR channel flow resistance threshold value data is obtained from the ECU and compared with the actual flow resistance value R of the EGR channel: if the actual flow resistance value R of the EGR channel is less than the EGR channel flow resistance threshold value data, a judgment signal is generated to not intervene in the flow resistance; if the actual flow resistance value R of the EGR channel is greater than the EGR channel flow resistance threshold value data, a judgment signal is generated to immediately terminate the fin voltage regulation.

[0018] Furthermore, after the judgment signal of not intervening in flow resistance is generated, the real-time NOx concentration data of the exhaust gas is compared with the NOx limit data of the current operating condition, and the obtained value is marked as the NOx difference. It is then compared with a preset judgment threshold: a NOx correction factor is generated based on the comparison result.

[0019] Furthermore, the system receives the baseline value of the fin adjustment voltage and the pre-instruction for fin heat exchange area adjustment from the temperature change data analysis module, as well as the NOx correction factor and flow resistance intervention judgment signal from the NOx status analysis module. After comprehensive integration and calculation, the system obtains the instruction to execute the fin action and feeds back the final fin adjustment voltage value and the actual fin action status to the NOx control platform in real time.

[0020] An EGR cooler with a variable thermal structure is provided. The EGR cooler adopts a dynamic regulating valve design of a variable cross-section EGR cooler, and sharkskin micro-textures are arranged along the main exhaust gas direction. The internal microstructure of the cooler is linked with the variable cross-section valve for optimized EGR cooling control.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention uses an EGR multi-source data acquisition module to periodically acquire core data such as inlet and outlet exhaust gas temperature, NOx concentration, and channel pressure, providing a comprehensive basis for judging operating conditions; the temperature change data analysis module generates fin adjustment pre-commands based on cooling efficiency and engine real-time efficiency, combined with exhaust gas temperature thresholds; under high-temperature conditions, the fins are controlled to fully expand and branch out, significantly increasing the heat exchange area and enhancing exhaust gas cooling to suppress in-cylinder NOx generation; under low-temperature conditions, the fins are controlled to partially shrink and adhere to the wall, reducing the effective heat exchange area and avoiding HC condensation and soot mixing to form coking, thus balancing anti-coking and cooling requirements;

[0023] 2. This invention uses a NOx state analysis module to calculate flow resistance and compare it with NOx concentration to generate a NOx correction factor and flow resistance intervention signal. This ensures that the fin adjustment not only matches the temperature requirements but also directly responds to NOx emission limits. At the same time, it avoids the risk of channel blockage caused by excessive flow resistance, achieving coordinated control of temperature, NOx, and flow resistance. This allows the EGR cooler to adapt to all engine operating conditions from idle to rated speed, meeting the NOx control accuracy requirements under different operating conditions while avoiding the shortcomings of traditional fixed structures. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the method of the present invention;

[0026] Figure 2 This is a schematic diagram of the EGR cooler structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the control flow of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1: Please refer to Figure 1 - Figure 3As shown, this embodiment is an EGR cooler with a changeable thermal structure and its NOx control method, including a NOx control platform. The NOx control platform is communicatively connected to an EGR multi-source data acquisition module, a temperature change data analysis module, a NOx status analysis module, and an intelligent optimization and control module.

[0030] The EGR multi-source data acquisition module identifies the target vehicle as the data acquisition source. Based on the single start time of the target vehicle's EGR cooler to the current data upload deadline, it marks it as a single-cycle monitoring period. The single-cycle monitoring period is divided into i cycle nodes, where i is a natural number greater than zero.

[0031] According to the cycle nodes, the temperature of the exhaust gas passing through the inlet area of ​​the EGR cooler is first acquired and marked as the initial temperature value of the EGR inlet exhaust gas. At the same time, a temperature sensor of the same model is embedded at the corresponding position of the EGR cooler outlet pipe to collect data on the temperature of the exhaust gas after cooling treatment and mark it as the EGR outlet exhaust gas cooling temperature value. The two sets of temperature data are collected periodically according to the cycle nodes and transmitted to the NOx control platform for real-time updates and storage, as a basis for subsequent analysis. The obtained initial temperature value of the EGR inlet exhaust gas and the EGR outlet exhaust gas cooling temperature value are summarized and marked as an exhaust gas temperature comprehensive data package.

[0032] A high-precision NOx sensor is deployed on the exhaust gas emission pipe downstream of the EGR cooler outlet. The NOx content in the cooled exhaust gas is collected at periodic nodes and marked as the real-time NOx concentration data value of the exhaust gas. At the same time, pressure sensors are deployed at key nodes in the internal channel of the EGR cooler to collect the initial pressure data value at different locations in the channel in real time. The obtained NOx concentration data value and initial pressure data value are summarized and marked as a comprehensive emission data package.

[0033] The temperature change data analysis module, after acquiring the comprehensive exhaust gas temperature data package, randomly selects the initial exhaust gas temperature value at the EGR inlet and the cooling temperature value at the EGR outlet of one cycle node. Based on the real-time engine efficiency value generated by the current target vehicle operation, it analyzes the difference between the initial exhaust gas temperature value at the EGR inlet and the cooling temperature value at the EGR outlet, and marks it as the cooling difference value. It also compares the difference between the factory-preset cooling medium temperature threshold in the EGR cooler label and the initial exhaust gas temperature value at the EGR inlet, and marks it as the cooler difference value. The actual cooling efficiency value of the EGR cooler corresponding to the current cycle node is obtained by dividing the cooling difference value by the cooler difference value. The actual cooling efficiency value is used to reflect the cooling and heat dissipation performance of the target vehicle for exhaust components.

[0034] The engine real-time efficiency value is based on the NOx control platform and the ECU module on the target vehicle system. The processed real-time engine speed data is summarized according to the periodic nodes and sent to the NOx control platform via the vehicle CAN bus.

[0035] After obtaining the actual cooling efficiency value and the engine real-time efficiency value, based on the preset engine design and bench calibration results within the NOx control platform, the corresponding engine design operating condition range and rated speed design value are extracted and marked as the speed comparison threshold. The lowest calibration value of the cooling efficiency of the target vehicle of the same type during bench calibration is set as the cooling efficiency threshold. The actual cooling efficiency value and the engine real-time efficiency value are compared and analyzed with the cooling efficiency threshold and the speed comparison threshold.

[0036] If the engine's real-time efficiency value is not within the range of the speed comparison threshold, and the actual cooling efficiency value is less than the cooling efficiency threshold, then it is determined that there is an abnormal engine idling speed and an abnormal cooling efficiency, and an invalid data signal is generated. The invalid data signal is sent to the NOx control platform, which simultaneously triggers two operations: first, it suspends the calculation of the subsequent basic fin adjustment voltage reference value to avoid control errors caused by invalid data; second, it activates the fault alarm mechanism. The NOx control platform transmits the fault signal to the vehicle's instrument panel, illuminates the EGR system fault light, and stores the fault code in the background, prompting maintenance personnel to check the corresponding components according to the fault code.

[0037] If the engine's real-time efficiency value is within the range of the speed comparison threshold, and the actual cooling efficiency value is greater than or equal to the cooling efficiency threshold, then the speed data and cooling efficiency data are deemed valid, and a log is generated. After confirming that the current input data meets the calibration range and there are no potential system faults, the system then enters the operating condition matching phase.

[0038] It should be noted that the design operating range of a diesel engine is 600 r / min. Below this value, idling speed fluctuations and unstable exhaust gas flow are likely to occur. The rated speed design value is 2500 r / min. Above this value, the moving parts of the engine will be overloaded and the exhaust gas temperature will exceed the heat resistance limit of the cooler. Therefore, the speed comparison threshold is constructed to cover the speed range of 600-2500 r / min. Outside this range, there is no corresponding speed-efficiency-voltage matching data in the mapping table, and forced matching will lead to inaccurate control.

[0039] After the log is generated, the basic cooling fin voltage mapping table pre-stored in the NOx control platform is retrieved. It is calibrated through previous bench tests and covers the initial values ​​of fin adjustment voltage corresponding to different speeds and different cooling efficiencies. The actual cooling efficiency value and the real-time engine efficiency value in the log are compared with the basic cooling fin voltage mapping table. The initial voltage value corresponding to the actual cooling efficiency value, the real-time engine efficiency value and the speed that is closest to the actual cooling efficiency value and the engine efficiency value is selected in the basic cooling fin voltage mapping table and marked as the basic fin adjustment voltage reference value, which is used as the basic voltage reference for subsequent fin adjustment.

[0040] It should be noted that the obtained basic fin adjustment voltage reference value is output to the intelligent optimization and control module in real time to reflect the initial adjustment requirements under the current speed and cooling efficiency. Subsequently, it is necessary to combine the NOx correction factor and flow resistance intervention judgment signal of the NOx status analysis module to finally generate the actual voltage driving the fin movement, so as to achieve precise control that takes into account both cooling efficiency and NOx control.

[0041] When the baseline fin regulating voltage is generated, the exhaust gas temperature threshold is extracted from the information stored on the NOx control platform regarding engine thermal management characteristics, emission system collaborative operation requirements, and bench test calibration records. This threshold is then compared and analyzed with the initial exhaust gas temperature value at the EGR inlet.

[0042] If the initial temperature of the EGR inlet exhaust gas is lower than the exhaust gas temperature threshold, it is determined to be a low-temperature operating condition, generating a pre-instruction for the fins to shrink and adhere to the wall; reducing the effective heat exchange area and avoiding excessively cold exhaust gas, HC will condense on the cooler channel wall and mix with Soot to form viscous carbon deposits, which will cause long-term accumulation to block the channel and reduce cooling efficiency.

[0043] If the initial temperature of the EGR inlet exhaust gas is higher than the exhaust gas temperature threshold, it is determined to be a high-temperature operating condition, and a pre-command is generated to fully deploy the fins in a branched shape; this increases the effective heat exchange area, enhances heat dissipation, and reduces NOx generation in the cylinder; this pre-command will serve as the basis for the temperature dimension adjustment of the intelligent optimization and control module.

[0044] The NOx status analysis module, based on the initial pressure data covered in the comprehensive emission data package, marks the recorded data generated in the inlet and outlet areas of the EGR cooler as static inlet data P1 and static outlet data P2, respectively, among all the data covered in the selected period node. Since the pressure decreases due to the resistance of the exhaust gas passing through the EGR cooler to the outlet area, the pressure difference PR is calculated using the formula PR = static inlet data P1 - static outlet data P2. The result is always positive. If a negative value appears, it is determined that the sensor is faulty and needs to be collected again.

[0045] Based on the deployment of flow sensors in the inlet area of ​​the EGR cooler, real-time exhaust gas flow data is collected. This data is processed to eliminate fluctuations caused by temperature and pressure. Increased temperature or decreased pressure can lead to volume expansion, resulting in large fluctuations in the real-time exhaust gas flow data. The collected real-time exhaust gas flow data is converted into volumetric flow rate under standard conditions. The standard conditions are a temperature of 0℃ and a pressure of 101325Pa. The standard condition flow rate is calculated as: real-time exhaust gas flow rate data × z × (real-time pressure / standard pressure), where z represents the temperature correction factor. This corrects the volumetric flow rate of the exhaust gas at the real-time temperature to the volumetric flow rate at the standard temperature, eliminating the influence of temperature changes on gas volume.

[0046] The EGR cooler pipe is a circular channel, and its flow area = pi × the square of the channel radius. Based on the pressure difference, standard flow rate and flow area, the flow rate of the exhaust gas is further verified. The actual flow resistance value R of the EGR channel is calculated as: effective pressure difference PR / (standard flow rate × flow area). This is based on the resistance that exhaust gas needs to overcome when passing through a unit area channel per unit volume and unit time. The larger the actual flow resistance value of the EGR channel, the more severe the obstruction of exhaust gas flow and the higher the risk of coking and blockage of the channel.

[0047] After obtaining the actual flow resistance value R of the EGR channel, the flow resistance threshold value data of the EGR channel is obtained from the ECU based on the NOx control platform and compared and analyzed with the actual flow resistance value R of the EGR channel. It is represented as the safety threshold value calibrated in the early stage, which is used to determine whether there is coking blockage in the channel.

[0048] If the actual flow resistance value R of the EGR channel is less than the flow resistance threshold value of the EGR channel, it is determined that there is no risk of blockage in the channel, and a judgment signal is generated that no flow resistance intervention is performed.

[0049] If the actual flow resistance value R of the EGR channel is greater than the EGR channel flow resistance threshold value, it is determined that there is a risk of blockage in the channel, and a judgment signal to immediately terminate the fin voltage regulation is generated. This signal has the highest priority and will directly affect the command output of the subsequent intelligent control module.

[0050] Upon receiving a signal indicating that no flow resistance intervention is required, the NOx limit data for the current operating condition is retrieved from the ECU based on the NOx control platform. This data is pre-stored in the ECU's NOx limit mapping table and dynamically matched according to engine speed, load, and other operating conditions. The real-time NOx concentration data of the exhaust gas is compared with the NOx limit data for the current operating condition, specifically:

[0051] The NOx difference is calculated as follows: Real-time NOx concentration data in exhaust gas × w - NOx limit data under current operating conditions × e, where w and e represent correction factors for the real-time NOx concentration data in exhaust gas and the NOx limit data under current operating conditions, respectively, with values ​​ranging from 0.8 to 1.2. The NOx difference is then compared with a preset judgment threshold.

[0052] When the NOx difference is higher than the judgment threshold and the correction factor is greater than 1, a signal to increase the fin size is generated to adjust the voltage and enhance the cooling effect.

[0053] When the NOx difference is lower than the judgment threshold and the correction factor is less than 1, a fin reduction signal is generated to adjust the voltage and avoid overcooling.

[0054] Example 2:

[0055] The intelligent optimization and control module receives the basic fin adjustment voltage reference value and fin heat exchange area adjustment pre-command from the temperature change data analysis module, as well as the NOx correction factor and flow resistance intervention judgment signal from the NOx status analysis module, and performs comprehensive integration calculations.

[0056] Based on the flow resistance intervention judgment signal at the current cycle node: if it is a judgment signal to immediately terminate fin voltage regulation, directly set the final fin regulation voltage value to 0;

[0057] If the judgment signal does not involve flow resistance intervention, the basic fin adjustment voltage reference value is multiplied by the NOx correction factor to obtain the final fin adjustment voltage value, which is the voltage basis for driving the fin action.

[0058] By combining the pre-command for adjusting the fin heat exchange area with the final fin adjustment voltage value, the fin action can be further refined:

[0059] If the fins partially shrink and adhere to the wall as instructed, and the final voltage value is low, the piezoelectric ceramic drive mechanism is controlled to generate microscale mechanical deformation, causing the biomimetic shark skin microstructure fins to shrink towards the channel wall, reducing the effective heat exchange area. The degree of shrinkage is positively correlated with the voltage value; the lower the voltage, the more obvious the shrinkage.

[0060] If the fins are fully extended in a branched shape as a pre-command, or if the real-time NOx concentration data of the exhaust gas is higher than the limit and the NOx correction factor is greater than 1, the piezoelectric ceramic drive mechanism is controlled to drive the fins to fully extend, increasing the effective heat exchange area. The degree of extension is positively correlated with the voltage value; the higher the voltage, the more fully the fins are extended.

[0061] After the fins are activated, the intelligent optimization and control module feeds back the final fin adjustment voltage value and the actual fin action status to the NOx control platform in real time. The platform then transmits this feedback data back to the EGR multi-source data acquisition module, temperature change data analysis module, and NOx status analysis module. Each module updates its data acquisition and analysis logic based on the feedback data, realizing a closed-loop control of acquisition-analysis-control-feedback. This ensures that the EGR cooler can balance the anti-coking requirements and NOx control targets under different operating conditions, avoiding coking and blockage of HC, Sof, and Soot under low-temperature conditions, while improving cooling efficiency and reducing NOx emissions under high-temperature or high-NOx conditions.

[0062] Combining Embodiment 1 and Embodiment 2, in the data processing stage, the temperature change data analysis module will compare the actual cooling efficiency with the engine efficiency with a preset threshold. If abnormal engine idling or low cooling efficiency occurs, an invalid data signal will be generated immediately, and the vehicle fault light alarm and background fault code storage will be triggered simultaneously. Maintenance personnel can quickly locate sensor faults or engine idling problems through the fault codes to avoid secondary damage caused by invalid control.

[0063] The NOx status analysis module monitors the actual flow resistance of the EGR channel in real time. When the flow resistance exceeds the threshold, it generates a high-priority signal to immediately terminate fin adjustment, preventing fin movement from exacerbating channel blockage and avoiding the risk of cooler failure due to coking. After executing fin movement, the intelligent optimization and control module feeds back the final voltage value and fin status to the NOx control platform in real time. Each module updates the next acquisition and analysis logic based on the feedback data, forming a closed loop of acquisition-analysis-control-feedback-iteration, ensuring that the control parameters continuously adapt to changes in operating conditions and reducing system losses caused by parameter inaccuracies.

[0064] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0065] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A NOx control method for an EGR cooler with a variable thermal structure, characterized in that, This includes a NOx control platform, which is connected to an EGR multi-source data acquisition module, a temperature change data analysis module, a NOx status analysis module, and an intelligent optimization and control module. The EGR multi-source data acquisition module identifies the target vehicle as the data acquisition source, acquires comprehensive exhaust gas temperature data based on the EGR cooler inlet and outlet areas, and acquires comprehensive emission data based on sensors deployed in the EGR cooler inlet and outlet pipes. The temperature change data analysis module analyzes the actual cooling efficiency value of the exhaust gas temperature comprehensive data package and generates a pre-command for adjusting the fin heat exchange area by combining it with the engine's real-time efficiency value. The NOx status analysis module generates NOx correction factors and flow resistance intervention judgment signals based on the pipe status of the EGR cooler pipes, as well as the joint analysis of exhaust gas flow resistance and exhaust gas concentration. The intelligent optimization and control module integrates and analyzes the signal results obtained from multi-step joint judgment to finally obtain the execution command to control the fin movement and optimize the adjustment method.

2. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 1, characterized in that, The EGR multi-source data acquisition module determines the target vehicle as the data acquisition source, and first acquires the temperature of the exhaust gas passing through the EGR cooler inlet area according to the cycle node, and marks it as the initial temperature value of the EGR inlet exhaust gas, and marks the temperature at the corresponding position of the EGR cooler outlet pipe as the cooling temperature value of the EGR outlet exhaust gas, and summarizes and marks them as the exhaust gas temperature comprehensive data package. Based on the NOx content in the exhaust gas after cooling treatment collected at the periodic nodes, it is marked as the real-time NOx concentration data value of the exhaust gas. The initial pressure data value at different locations in the channel is collected in real time. The obtained NOx concentration data value and initial pressure data value are summarized and marked as the comprehensive emission data package.

3. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 1, characterized in that, The temperature change data analysis module randomly selects the initial temperature value of the EGR inlet exhaust gas and the cooling temperature value of the EGR outlet exhaust gas at one of the cycle nodes. By analyzing the difference between the initial temperature value of the EGR inlet exhaust gas and the cooling temperature value of the EGR outlet exhaust gas, it marks this as the cooling difference. It also obtains the difference by comparing the factory-preset cooling medium temperature threshold in the cooler on the EGR cooler label with the initial temperature value of the EGR inlet exhaust gas, and marks this as the cooler difference. Finally, it divides the cooling difference by the cooler difference to obtain the actual cooling efficiency value of the EGR cooler corresponding to the current cycle node.

4. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 3, characterized in that, The NOx control platform and the ECU module of the target vehicle system acquire the engine's real-time efficiency value and speed comparison threshold. The actual cooling efficiency value and the engine's real-time efficiency value are compared and analyzed with the cooling efficiency threshold and the speed comparison threshold. If the engine's real-time efficiency value is not within the range of the speed comparison threshold and the actual cooling efficiency value is less than the cooling efficiency threshold, an invalid data signal is generated. If the engine's real-time efficiency value is within the range of the speed comparison threshold and the actual cooling efficiency value is greater than or equal to the cooling efficiency threshold, a log is generated.

5. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 4, characterized in that, By comparing the actual cooling efficiency value recorded in the log with the real-time engine efficiency value, and comparing them with the basic cooling fin voltage mapping table, the cooling efficiency value and the initial voltage value corresponding to the engine speed that are closest to the actual cooling efficiency value and the real-time engine efficiency value in the basic cooling fin voltage mapping table are selected and marked as the basic fin adjustment voltage reference value. At the same time, the state ratio between the initial temperature value of the EGR inlet exhaust gas and the exhaust gas temperature threshold is judged: if the result is determined to be a low temperature condition, a pre-command for partial fin contraction and wall adhesion is generated; if the result is determined to be a high temperature condition, a pre-command for the fins to fully expand and branch out is generated.

6. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 1, characterized in that, The NOx status analysis module marks the recorded data generated by comparing the inlet and outlet areas of the EGR cooler with all the data within the selected periodic nodes as static inlet data P1 and static outlet data P2, respectively, and obtains the pressure difference value through a formula. Based on the real-time exhaust gas flow data of the EGR cooler inlet area, the standard flow rate is obtained by processing according to the formula. The EGR cooler pipe is a circular channel, and the flow area is obtained by formula analysis. The actual flow resistance value R of the EGR channel is obtained by comparing the standard flow rate, flow area and pressure difference.

7. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 6, characterized in that, Based on the NOx control platform, the EGR channel flow resistance threshold value data is obtained from the ECU and compared with the actual flow resistance value R of the EGR channel. If the actual flow resistance value R of the EGR channel is less than the EGR channel flow resistance threshold value data, a judgment signal is generated to not intervene in the flow resistance; if the actual flow resistance value R of the EGR channel is greater than the EGR channel flow resistance threshold value data, a judgment signal is generated to immediately terminate the fin voltage regulation.

8. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 7, characterized in that, After the judgment signal of not intervening in flow resistance is generated, the real-time NOx concentration data of the exhaust gas is compared with the NOx limit data of the current operating condition, and the obtained value is marked as the NOx difference. It is then compared with a preset judgment threshold: a NOx correction factor is generated based on the comparison result.

9. The NOx control method for an EGR cooler with a changeable thermal structure according to claim 8, characterized in that, The system receives the baseline value of the fin adjustment voltage and the pre-instruction for fin heat exchange area adjustment from the temperature change data analysis module, as well as the NOx correction factor and flow resistance intervention judgment signal from the NOx status analysis module. It performs comprehensive integration calculations to obtain the instruction to execute the fin action and feeds back the final fin adjustment voltage value and the actual fin action status to the NOx control platform in real time.

10. An EGR cooler with a variable thermal structure, used in the NOx control method of the EGR cooler with a variable thermal structure according to any one of claims 1-9, characterized in that, The EGR cooler adopts a dynamic regulating valve design for a variable cross-section EGR cooler, and sharkskin micro-textures arranged along the main exhaust gas direction. The internal microstructure of the cooler is linked with the variable cross-section valve for optimized EGR cooling control.

Images