A method for dynamically adjusting back pressure of exhaust gas aftertreatment flow channel

Abstract

The application relates to the technical field of non-electric variable control or regulation systems, and discloses a kind of exhaust gas aftertreatment flow channel back pressure dynamic regulation method, comprising: obtaining supply source phase reference signal and establishing cycle mapping;Extracting fluid channel pressure signal pulse range change rate to determine feedforward factor;The pressure signal trough interval is determined as the action window;Determine the target regulation instruction based on the reference value determined by the feedback deviation and compensate using the feedforward factor;Drive the regulating mechanism to displace within the action window, so that the response peak is locked in the trough interval, the application locks the regulating action in the low-energy phase, avoids the kinetic energy intervention of fluid pulse on the regulating mechanism, and reduces mechanical wear;Using pulse characteristic feedforward compensation makes the regulation instruction perceive the flow field trend, while smoothing the signal, improves the response speed, and maintains the pressure balance under transient operating conditions.

Description

Technical Field

[0001] This invention belongs to the technical field of control or regulation systems for non-electrical variables, and particularly relates to a method for dynamic adjustment of back pressure in exhaust gas aftertreatment channels. Background Technology

[0002] Currently, for fluid systems with periodic pressure pulses, existing technologies typically collect the average value of the fluid signal as a feedback signal and combine it with control algorithms to implement closed-loop regulation. Because the exhaust process of an internal combustion engine exhibits periodic pulse characteristics, the pressure inside the exhaust channel fluctuates drastically with the crankshaft angle, dividing the exhaust cycle into a pressure peak region corresponding to the exhaust stroke and a pressure valley region corresponding to the gas exchange overlap. The evolution of control strategies faces bottlenecks. For example, the utility model patent with authorization announcement number CN223648643U discloses an automatic back pressure valve pressure adjustment device, in which a stepper motor drives the first connecting rod to rotate, and the threaded engagement drives the second connecting rod to move and change the compression of the pressure spring, and the closed-loop automatic adjustment is based on the feedback data of the pressure sensor.

[0003] In such a periodic alternating flow field, existing technologies often neglect the time-domain distribution characteristics of exhaust pulses. If the actuator adjusts the opening during the pressure peak of the exhaust stroke, the valve plate will be subjected to transient fluid impact force, thereby inducing high-frequency mechanical vibration in the drive mechanism and accelerating the fatigue wear of the reduction gear set. To maintain control stability, the industry generally uses filtering algorithms to extract the envelope mean value of the controlled fluid pressure. However, increasing the filtering depth will cause signal time-domain lag, making it impossible for the controller of the control system to perceive the step change of the flow field energy level in real time. Ultimately, this leads to a technical contradiction between dynamic response speed and adjustment stability. Even if a static prediction model is used to compensate for the advance of the actuator, the pressure wave propagation velocity will change nonlinearly due to exhaust temperature fluctuations. In addition, the resistance drift generated by mechanical components during long-term operation makes it difficult to accurately lock the preset adjustment phase in the low-energy window of the flow field.

[0004] Therefore, the technical problem to be solved by this invention is how to achieve precise physical overlap between the adjustment action and the low-energy range of the controlled variable signal while ensuring the system response speed, and to dynamically eliminate the phase shift caused by changes in environmental parameters and mechanical characteristics. Summary of the Invention

[0005] This invention provides a method for dynamically adjusting the back pressure of an exhaust gas aftertreatment channel, comprising the following steps:

[0006] Step S101: Obtain the phase reference signal of the fluid supply source and establish the phase mapping relationship between the fluid circulation stroke and the phase reference signal to determine the phase reference reference for back pressure regulation;

[0007] Step S102: Real-time acquisition of pressure signals in the fluid discharge channel, and capture of instantaneous peak and valley values ​​of pressure signals in each phase cycle;

[0008] Step S103: Use the instantaneous peak value minus the instantaneous valley value to determine the pulse range of the current cycle, calculate the rate of change of the pulse range between two adjacent cycles, and determine the range variability feedforward factor based on the rate of change of the pulse range.

[0009] Step S104: Based on the operating frequency signal of the fluid supply source and the system load parameters, identify the fluid circulation overlap valley range in the pressure signal, and define the fluid circulation overlap valley range as the action allowable window of the back pressure regulating actuator.

[0010] Step S105: Extract the envelope mean of the pressure signal and use it as the pressure feedback signal. Perform proportional-integral-derivative calculation based on the deviation between the pressure feedback signal and the target pressure value to determine the reference amplitude of the adjustment command.

[0011] Step S106: When the rate of change of the pulse range exceeds the preset change threshold, the range rate feedforward factor is used to perform gain compensation on the reference amplitude in order to determine the target adjustment command.

[0012] Step S107: Drive the back pressure regulating actuator to perform displacement action according to the target regulation command within the action allowable window, so that the peak moment of the displacement response of the back pressure regulating actuator is locked within the fluid circulation overlap valley range.

[0013] Preferably, step S107 further includes a step of correcting the adjustment phase by monitoring local disturbances within the action allowable window: extracting the rate of change of the pressure signal within the action allowable window, identifying the pressure characteristic wave caused by the action of the back pressure regulating actuator; when the frequency of the pressure characteristic wave exceeds a preset value... When the Hz interference threshold is reached, the opening time of the action allowable window is determined to lag behind the starting point of the fluid circulation overlap valley interval; based on the offset of the pressure characteristic wave relative to the starting point, the advance of the target adjustment command is corrected online so that the response time of the displacement action is aligned with the phase center of the fluid circulation overlap valley interval.

[0014] Preferably, in step S104, the method for identifying the overlapping valley interval of the fluid circulation includes: acquiring the operating frequency signal and energy input parameters of the fluid supply source; retrieving a preset pressure pulse mapping spectrum based on the operating frequency signal and energy input parameters to determine the phase distribution characteristics of pressure fluctuations under the current operating condition; wherein, the pressure pulse mapping spectrum is pre-established by recording the valley distribution patterns of pressure signals corresponding to different frequency and load combinations under calibrated operating conditions; and defining the continuous phase region in the phase distribution characteristics where the pressure value is lower than a preset energy threshold as the overlapping valley interval of the fluid circulation.

[0015] Preferably, in step S106, the logic for determining the target adjustment command follows the following formula: ,in, Adjustment instructions for the target. As the reference amplitude, The pulse range of the current period. The pulse range of the previous cycle. This is the preset feedforward compensation coefficient.

[0016] Preferably, after step S107, the method further includes a step of performing a mechanical health diagnosis on the back pressure regulating actuator: acquiring the drive current signal of the back pressure regulating actuator when it performs an action within the action allowable window; extracting the transient peak current of the drive current signal at the beginning stage of the displacement action; when the transient peak current is within a preset range... When the transient peak current shows a monotonically increasing trend within the h monitoring period, the deviation rate of the transient peak current relative to the initial current reference value is calculated, and the wear condition of the internal transmission components of the back pressure regulating actuator is evaluated based on the deviation rate.

[0017] Preferably, in step S103, the pulse range is also used to correct the width of the action allowable window: when the pulse range increases and exceeds the first range threshold, the phase range of the action allowable window is contracted; when the pulse range decreases and is lower than the second range threshold, the phase range of the action allowable window is expanded.

[0018] Preferably, in step S102, a high-frequency pressure sampling link is used when acquiring the pressure signal, and the sampling frequency is set to the highest main frequency of the fluid circulation stroke. More than twice as high, to capture instantaneous peaks and troughs.

[0019] Preferably, in step S107, the displacement action of the back pressure regulating actuator adopts a segmented step adjustment logic: the total displacement is determined according to the target adjustment command; the total displacement is decomposed into multiple step increments; the step increments are executed sequentially within multiple consecutive action allowable windows until the total displacement is reached.

[0020] Preferably, the mechanical health diagnosis also includes a channel flow resistance monitoring step: extracting the pressure reference value at the instantaneous trough of the pressure signal; monitoring the cumulative drift of the pressure reference value over operating time; and generating a maintenance warning signal for the fluid discharge channel when the increase in the pressure reference value exceeds a preset resistance alarm threshold.

[0021] Preferably, the emergency control steps include: continuously monitoring the validity status of the phase reference signal; when it is determined that the phase reference signal is lost, exiting the phase locking adjustment logic based on the phase mapping relationship and switching to the backup control mode for full phase adjustment based on the envelope mean of the pressure signal.

[0022] Compared with existing technologies, the present invention's method for dynamic adjustment of back pressure in the exhaust gas aftertreatment channel has the following advantages:

[0023] 1. In the dynamic adjustment of back pressure in the exhaust gas aftertreatment channel, the displacement stroke of the actuator is adjusted so that it coincides with the valley range of the channel pressure pulse in the time dimension. This avoids the actuator from being subjected to transient fluid impact loads during the peak of exhaust pressure, reduces the reverse impact wear of the precision gear set inside the drive mechanism, and extends the mechanical life of the actuator in high temperature and high vibration environments.

[0024] 2. Extract the change rate characteristics of the back pressure in the flow channel and identify the high-frequency disturbance signal generated by the edge of the erroneous pulse of the adjustment action. Based on this, correct the response time parameter of the actuator online, so that the advance of the adjustment command can automatically evolve with the ambient temperature and mechanical aging state, and ensure that the action window of the actuator is always locked in the low energy phase of the flow field, eliminating the adjustment phase lock-up caused by the drift of physical characteristics.

[0025] 3. Extract the changing trend of the single-cycle pulse pressure range and use it as a compensation factor for the adjustment step size. Combined with the pressure mean feedback logic, optimize the control logic of the non-electric variable adjustment system and construct a composite control strategy with predictive capability. This enables the amplitude of the adjustment command to a priori sense the sudden change trend of the flow field energy, thereby improving the system's response speed to dynamic conditions while retaining signal smoothing and filtering, and suppressing back pressure fluctuations during load transients. Attached Figure Description

[0026] Figure 1 This is a flowchart of a back pressure dynamic adjustment method based on pulse feature feedforward according to the present invention;

[0027] Figure 2 This is a timing diagram of the signal interaction and fault emergency mode switching of the regulating system components in this invention. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0029] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0030] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication between two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0031] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," 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 present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] This invention provides a method for dynamic adjustment of back pressure in an exhaust gas aftertreatment channel. It establishes a phase mapping relationship between the fluid circulation stroke and a phase reference signal, thereby determining the phase reference benchmark for back pressure adjustment. The system collects pressure signals in the fluid discharge channel in real time, capturing the instantaneous peak and valley values ​​of the pressure signal within each phase cycle. The pulse range of the current cycle is determined by subtracting the instantaneous valley value from the peak value, and the rate of change of the pulse range between two adjacent cycles is calculated to determine the range rate feedforward factor. The 50Hz interference threshold is set based on the coupling boundary between the electromagnetic resonant frequency of the actuator's DC motor and the order frequency of the airflow pulse, used to distinguish between normal back pressure fluctuations and abnormal mechanical intervention disturbances. When correcting the advance of the action, the system calculates the pressure gradient before and after the start point of the allowable action window in real time. If an oscillation frequency exceeding 50Hz is detected and its duration exceeds three sampling cycles, it is determined to be actuator hysteresis. At this time, the system initiates a step correction program: according to five crankshafts corresponding to each 10ms phase drift. The mapping ratio of the turning angle increases the advance of the target adjustment command online, triggering the motor drive signal in advance to offset the exhaust pressure wave propagation delay caused by the length of the exhaust manifold, ensuring that the mechanical action precisely cuts into the exhaust wave trough. The system acquires the operating frequency signal of the fluid supply source and the system load parameters, identifies the fluid circulation overlap valley range in the pressure signal, and defines the fluid circulation overlap valley range as the action allowable window of the back pressure adjustment actuator. The processing unit extracts the envelope mean of the pressure signal and uses it as the pressure feedback signal. Based on the deviation between the pressure feedback signal and the target pressure value, it performs proportional-integral-differential calculations to determine the reference amplitude of the adjustment command. When the rate of change of the pulse range exceeds the preset change threshold, the system uses the range rate feedforward factor to perform gain compensation on the reference amplitude, determines the target adjustment command, and drives the back pressure adjustment actuator to perform displacement action according to the target adjustment command within the action allowable window, so that the peak moment of the displacement response of the back pressure adjustment actuator is locked within the fluid circulation overlap valley range.

[0033] To correct the response hysteresis of the actuator, the method monitors local disturbances within the allowable action window to correct the adjustment phase. Specifically, it extracts the rate of change of the pressure signal within the allowable action window, identifies the pressure characteristic wave caused by the back pressure regulating actuator's action, and when the frequency of the pressure characteristic wave exceeds a preset value... When the Hz interference threshold is reached, the opening time of the action allowable window is determined to lag behind the starting point of the fluid circulation overlap valley interval. Based on the offset of the pressure characteristic wave relative to the starting point, the system online corrects the advance of the target adjustment command issuance, aligning the response time of the displacement action with the phase center of the fluid circulation overlap valley interval. When identifying the fluid circulation overlap valley interval, the operating frequency signal and energy input parameters of the fluid supply source are acquired. Based on the operating frequency signal and energy input parameters, a preset pressure pulse mapping spectrum is retrieved to determine the phase distribution characteristics of the pressure fluctuation under the current operating condition. Continuous phase regions where the pressure value is lower than the preset energy threshold are defined as the fluid circulation overlap valley interval. A pressure pulse mapping spectrum is established, with the crankshaft rotation angle as the reference point. As the phase zero point, with the full speed range The step size is rpm to collect fluid supply source pressure samples under different loads. The pressure pulse mapping spectrum is stored in the memory in a two-dimensional index table structure. The horizontal axis is the rotation speed at a step size of 100 revolutions per minute, and the vertical axis is the load percentage at a step size of 5%. Each index grid stores three key sections: the trough start phase angle, the trough end phase angle, and the reference pulse range under this operating condition.

[0034] In actual retrieval, if the current speed is between two index step points, the system uses proportional interpolation logic. For example, if the current speed is 1150 rpm, the phase angle values ​​at 1100 rpm and 1200 rpm are read separately, and a weighted average is calculated with each value accounting for 50%, serving as a reference value for the phase distribution characteristics of the current operating condition. This ensures smooth switching of the phase reference under continuous speed variation conditions. The system analyzes the pressure signal spectrum distribution and extracts the main frequency energy component, identifying continuous phase regions where the pressure value is below a preset energy threshold as fluid circulation overlap valley intervals. When the action allows local disturbances within the window, the system performs a process based on the collected high-frequency pressure data. A sliding window mid-range filter removes random spikes within a sampling period, and the pressure gradient change before and after the allowable window opening time is calculated in real time. The detected frequency is located at... When the oscillation waveform exceeds the preset noise threshold within the Hz interference threshold range, it is determined that the displacement action has entered the high-voltage pulse region, and the phase advance of the target adjustment command is increased. to The crankshaft angle is adjusted to reduce the energy proportion of the oscillation waveform below the background noise level; the logic for determining the target adjustment command follows the formula below: ,in, Adjust instructions for the target; The reference amplitude; This represents the pulse range of the current cycle. This represents the pulse range of the previous cycle; This is the preset feedforward compensation coefficient.

[0035] Select a preset operating point and adjust the reference amplitude of the adjustment command in steps under steady-state back pressure conditions. Simultaneously monitor the pressure signal within the emission channel and calculate the pulse range change. Compared with the reference amplitude unit change The ratio determines the system gain sensitivity coefficient. Here, This represents the change in pulse range. The feedforward compensation coefficient is the unit change in the reference amplitude. The system gain sensitivity coefficient The product of the reciprocal and the actuator response time constant is used to simulate a jump from low load to full load on an engine dynamometer. The peak exhaust back pressure overshoot is observed to remain within a preset safety threshold. If the overshoot exceeds a preset amplitude threshold, then... Increasing step size feedforward compensation coefficient This ensures that the peak value of the displacement response is phase-aligned with the center of the overlapping valley interval of the fluid circulation. To assess the mechanical health status, the system acquires the drive current signal of the back pressure regulating actuator when it performs actions within the permissible action window, extracts the transient peak current of the drive current signal at the beginning of the displacement action, and when the transient peak current is within a preset range... When the h-monitoring cycle shows a monotonically increasing trend, the deviation rate of the transient peak current relative to the initial current reference value is calculated to assess the wear condition of the internal transmission components of the back pressure regulating actuator. The pulse range is also used to correct the width of the action allowable window. When the pulse range increases and exceeds the first range threshold, the phase range of the action allowable window is narrowed; when the pulse range decreases and falls below the second range threshold, the phase range of the action allowable window is expanded. A high-frequency pressure sampling link is used when acquiring pressure signals, and the sampling frequency is set to the highest main frequency of the fluid circulation stroke. More than twice as high, to capture instantaneous peaks and troughs.

[0036] The displacement action of the back pressure regulating actuator adopts a segmented step-by-step adjustment logic. The total displacement is determined according to the target adjustment command, and then decomposed into multiple step increments. These step increments are executed sequentially within multiple consecutive action allowable windows until the total displacement is reached. Mechanical health diagnosis also includes a channel flow resistance monitoring step. This involves extracting the pressure reference value at the instantaneous trough of the pressure signal, monitoring the cumulative drift of the pressure reference value over operating time, and generating a maintenance warning signal for the fluid discharge channel when the increase in the pressure reference value exceeds a preset resistance alarm threshold. The system executes an emergency control step, continuously monitoring the effectiveness of the phase reference signal. When a judgment is made… When the fixed-phase reference signal is lost, the phase-locked adjustment logic based on phase mapping relationship is exited, and the system switches to the backup control mode of full-phase adjustment based on the envelope mean of the pressure signal. In addition, the system acquires the exhaust temperature signal and determines the propagation speed of the exhaust pressure wave in the flow channel, calculates the time delay parameter of the exhaust pressure wave from the cylinder exhaust valve to the actuator position, and uses the time delay parameter to dynamically correct the preset advance. In the pulse valley area of ​​the actuator action, a high-frequency micro-oscillation signal is superimposed on the adjustment command to drive the actuator to generate mechanical micro-vibration. The amplitude of the high-frequency micro-oscillation signal is less than the preset threshold that causes global fluctuations in the flow channel back pressure.

[0037] In a specific operating condition where amplitude adjustment is performed to correct exhaust resistance, the system executes a segmented step adjustment program to suppress flow field disturbances caused by the displacement of the adjustment blades. The processing unit determines the total displacement based on the target adjustment command. Using the formula Decompose the total displacement into Incremental step ,in, For incremental steps, This represents the total displacement. To determine the number of segments, the actuator displaces by one step increment within the first action's allowable window. The system maintains its current displacement and continuously monitors pressure signal fluctuations within the emission channel, waiting for the next phase cycle. In subsequent continuous... The above displacement action is repeated successively within the overlapping valley interval of the fluid circulation until the cumulative displacement reaches the total displacement. When the monitoring program detects that the phase reference signal is lost due to the interruption of the electrical link, the system triggers the emergency control procedure to maintain the regulation function. The processing unit exits the phase-locked regulation logic based on the phase mapping relationship and switches to the continuous regulation mode based on the average value of the pressure signal envelope. The system collects the pressure signal in the fluid discharge channel through the high-frequency pressure sampling link and performs low-pass filtering. The controller extracts the average value of the filtered signal envelope and uses it as the pressure feedback signal. Based on its deviation from the target pressure value, it performs proportional-integral-derivative calculations to generate a full-phase regulation command. In this mode, the actuator is no longer limited by the action allowable window and continues to displace throughout the entire phase cycle.

[0038] Example 1: At the operation site of heavy construction machinery equipped with a large-displacement turbocharged engine, when the system faces the condition of switching from idle load to full load output, the exhaust gas pulse energy in the emission channel is... The pressure increases non-linearly within milliseconds. Because the existing regulation logic uses the average pressure envelope extracted by low-pass filtering as feedback, the signal response lags behind the pressure evolution rate in the flow field, causing the exhaust back pressure to exceed the preset safety limit. Furthermore, the back pressure regulation actuator undergoes displacement adjustment during the pressure pulse peak, subjecting the transmission components to transient fluid loads. To address these conditions, the system acquires a phase reference signal to lock the back pressure regulation action execution time within the allowable action window determined by the overlapping valley range of the fluid circulation. Simultaneously, the high-frequency pressure sampling link captures the instantaneous peak value in each phase cycle. with instantaneous valley value To determine the pulse range The feedforward factor is determined using the range variability of adjacent periods, and the system is based on the formula... For the reference amplitude Gain compensation is performed, where, Adjustment instructions for the target. As the reference amplitude, The pulse range of the current period. The pulse range of the previous cycle. This is the preset feedforward compensation coefficient.

[0039] During the issuance of the aforementioned target adjustment command, the evolution trend of the pulse characteristics enables the system to respond to the flow field changes in advance before the envelope mean signal converges, ensuring that the back pressure adjustment actuator engages at the trough phase where the pressure is lower. The dynamic peak value of the measured back pressure is within the safety threshold range. Since the advance amount of the adjustment command issuance is corrected according to the rate of change of the local pressure signal within the action allowable window, the peak center of the displacement response is aligned with the pulse trough phase, avoiding the impact load of the high-pressure pulse on the adjustment blade. Through the combination of pulse characteristic information and phase locking mechanism, the adjustment stability of the after-processing system under dynamic operating conditions is maintained.

[0040] Example 2: When configuring a response frequency of not less than On an engine emissions aftertreatment test platform with a piezoelectric pressure sensor and crankshaft position signal extraction unit operating at kHz, the system's step response time is less than [a certain value]. The actuator of ms and the signal-to-noise ratio superimposed on the pressure sensor signal are 1. For random noise in dB, the experimental design uses the sampling period setting as a parameter trade-off point. This consideration is to balance the signal waveform capture accuracy with the processing unit's computational load. When the exhaust valve opening frequency increases, causing the pressure pulse main frequency bandwidth to widen, to avoid signal aliasing and ensure the instantaneous peak value... with instantaneous valley value The extraction accuracy and sampling frequency are set to [value]. kHz, while feedforward compensation coefficient The setting is based on the sensitivity analysis of the flow field inertia to the adjustment command, and the example value is selected under acceleration conditions. By establishing a multi-dimensional control system comprising the sample group of this invention, a control group A lacking feedforward factors, and a control group B lacking phase-locking mechanisms, in %, %and Monitor the peak overshoot of exhaust back pressure and the fluctuation of actuator drive current under % load intensity.

[0041] After the experiment is started, the system generates periodic exhaust pressure waves within the flow channel. The high-frequency pressure sampling link analyzes the geometric characteristics of the pressure signal in each phase cycle and uses the formula... The pulse range is calculated. Table 1 is a comparison of the performance indicators of different control strategies during the load change process. The table records the observed values ​​of the system during the switching process from idle speed to full load. The original input parameter is the load intensity of the fluid supply source, the key intermediate characteristic value is the range rate feedforward factor, and the final output result is the peak overshoot of the exhaust back pressure.

[0042]

[0043] Analysis of the measurement data in Table 1 shows that, under the same load intensity, the peak overshoot of the exhaust back pressure in the sample group of this invention is lower than that in the control group A. The reason for this is that the target adjustment command... A range rate feedforward compensation was introduced, enabling the system to correct the regulation amplitude in advance when the pressure envelope mean value, limited by low-pass filtering, had not yet fully reflected the dramatic changes in the flow field. In contrast, the transient current of the actuator in control group B during the initial stage... % load condition reached A, higher than the sample group of this invention A shows that in the absence of phase-locked guidance, the control group B's adjustment action was triggered in the pressure pulse peak region, causing the regulating blades to be subjected to airflow impact, which in turn induced an increase in the load current of the drive motor. The data confirms the synergistic effect of phase-locked logic and pulse characteristic feedforward in reducing mechanical load and improving adjustment accuracy; to verify the feedforward compensation coefficient To ensure the reasonableness of the numerical range, the experiment included an out-of-range control group that exceeded the preset boundary, and the current feedforward compensation coefficient. Set as At that time, the compensation gain of the target adjustment command is insufficient to offset the step rate of the flow field pressure, causing the exhaust back pressure to generate a pressure peak at the instant of the sudden change; while when Set as Furthermore, after exceeding the upper limit of the optimal range, noise-driven oscillations in the regulation command were observed in the system under stable operating conditions, and the variance of the back pressure signal increased from... Increase to The excessively high feedforward gain amplifies background interference in the sensor link, verifying that the required parameter range is a working window that balances operational response speed and control loop stability. Furthermore, frequency analysis of the pressure characteristic wave within the permissible action window reveals that when the advance of the adjustment command is corrected according to the rate of change of the pressure signal, the alignment error between the peak center and the trough phase of the displacement response stabilizes within a certain range. Within ° crankshaft rotation angle.

[0044] Example 3: This example combines Figures 1 to 2 This document describes a method for dynamically adjusting the back pressure of an exhaust gas aftertreatment channel. Figure 1As shown, step S101 acquires the phase reference signal of the fluid supply source, establishes the phase mapping relationship between the fluid circulation stroke and the phase reference signal to determine the phase reference benchmark for back pressure regulation, and then executes step S102 to acquire the pressure signal in the fluid discharge channel in real time, capturing the instantaneous peak value and instantaneous valley value of the pressure signal in each phase cycle. Next, step S103 uses the instantaneous peak value minus the instantaneous valley value to determine the pulse range of the current cycle, calculates the rate of change of the pulse range between two adjacent cycles, and determines the range rate feedforward factor based on the rate of change of the pulse range. Finally, step S104 identifies the fluid circulation overlapping valley value region in the pressure signal based on the operating frequency signal of the fluid supply source and the system load parameters. In the mean value range of the fluid circulation overlap valley is defined as the action allowable window of the back pressure regulating actuator. Further, step S105 is executed to extract the envelope mean value of the pressure signal and use it as the pressure feedback signal. Based on the deviation between the pressure feedback signal and the target pressure value, proportional integral and derivative calculations are performed to determine the reference amplitude of the regulation command. Step S106 is executed when the rate of change of the pulse range exceeds the preset change threshold. The range rate feedforward factor is used to compensate the gain of the reference amplitude to determine the target regulation command. Finally, step S107 is executed to drive the back pressure regulating actuator to perform displacement action according to the target regulation command within the action allowable window, so that the peak moment of the displacement response of the back pressure regulating actuator is locked within the fluid circulation overlap valley range.

[0045] like Figure 2 As shown, the control interaction process involves a fluid supply source, sensors, a monitoring module, a processing unit, and an actuator. The fluid supply source provides a phase reference signal, and the sensors transmit the phase signal to the monitoring module for continuous monitoring to detect the signal validity. When the phase signal is normal, the monitoring module confirms the signal is valid, and the processing unit responds and performs phase-locked adjustment. When the phase signal is determined to be lost, the monitoring module triggers emergency control, instructing the processing unit to exit the phase-locked mode and switch to backup control mode. In this backup path, the processing unit collects pressure signals and performs low-pass filtering, then extracts the envelope mean and generates a full-phase command through PID control to drive the actuator to perform continuous adjustment throughout the entire cycle.

[0046] Example 4: During the initialization phase before the system is put into operation, the method establishes a pressure pulse mapping spectrum with a two-parameter index. Technicians collect raw pressure samples under full engine speed and full load conditions, using speed step size... rpm and load step A gridded coordinate system is constructed, and each grid cell of the graph stores the exhaust valve opening time, the phase range of the scavenging overlap zone, and the amplitude of the reference pressure fluctuation under the corresponding operating condition. To address random high-frequency glitches in the high-frequency pressure sampling link, the system executes a method based on... The sliding window mid-value filtering process is applied to each sampling period, and the instantaneous peak value is located using the first-order difference sign change determination logic. and instantaneous valley value The specific determination criterion is as follows: when the pressure change rate of adjacent sampling points changes from positive to negative, and the current pressure value is greater than the preset effective amplitude threshold, the current sampling point is determined to be the instantaneous peak value in a physical sense. When extracting the envelope mean of the pressure signal, the system adopts a time window-based sliding average sampling strategy: the control unit continuously collects 64 pressure sample points at a frequency of 10000Hz and stores them in a cyclic first-in-first-out buffer. At the end of each sampling period, the processor removes the two noisiest samples in the buffer, sums the remaining 60 samples, shifts them six bits to the right, and performs an approximate division operation. The result of this operation is used as the current envelope mean feedback signal. Its update frequency is synchronized with the task cycle of the control unit, such as 10ms, so as to filter out high-frequency pressure pulse jitter while retaining the perception of the overall back pressure trend.

[0047] Feedforward compensation coefficient The settings follow the sensitivity balancing procedure. Under the calibration condition of constant load, the processing unit actively changes the unit amplitude of the target adjustment command. Monitoring the resulting pulse range Change Calculate the system gain sensitivity coefficient Sensitivity coefficient The calculation formula is as follows: ,in, This represents the system gain sensitivity coefficient. This represents the change in the pulse range; The feedforward compensation coefficient is the unit amplitude of the target adjustment command. Set as sensitivity coefficient The product of the reciprocal of the value and the system response time constant is stored in the controller's non-volatile memory. When calculating the target adjustment command, the processor reads the pulse range of the current cycle and the pulse range of the previous cycle, and performs difference calculation. To prevent logical collapse caused by the denominator being zero in the division operation, the system sets a numerical protection boundary: if the pulse range of the previous cycle is less than 0.5 kPa, the denominator is 0.5 kPa. The calibration steps for the feedforward compensation coefficient are as follows: at the engine constant speed calibration point, the coefficient is adjusted in steps of 100 millivolts per second. Increase the amplitude of the adjustment command and record the rate of change of the back pressure range. Multiply the reciprocal of this rate of change by the inherent response time of the actuator from receiving the command to the blade action (usually 20 to 50 ms). The product is the basic calibration value of the feedforward compensation coefficient. If the measured overshoot exceeds 5 kPa, the coefficient is gradually increased in increments of 0.05 until the overshoot converges to within the safe threshold. During phase correction within the allowable window of the action, the system extracts the phase offset angle of the pressure characteristic wave relative to the starting point of the overlapping valley interval of the fluid circulation. The system uses formula Calculate the phase correction amount of the advance timing. ,in, This is the phase correction amount. This is the angle mapping scaling factor. This is the phase offset angle.

[0048] At engine speed rpm step jump Feedforward compensation coefficient under transient acceleration conditions at rpm Drive target adjustment command This generates a gain jump that leads the envelope signal, enabling the back pressure regulating actuator to obtain driving force at the moment when the slope of the flow field kinetic energy fluctuation is at its maximum. At this point, the pulse range determined by the extreme value capture algorithm is... The expansion trend of the feedback pressure waveform, combined with the phase reference provided by the pressure pulse mapping spectrum, keeps the displacement response center of the back pressure regulating actuator at [position]. ° to Within the overlapping valley phase of the crankshaft rotation angle, the system achieves dynamic coupling between control commands and the physical flow field energy distribution in an environment of drastic changes in fluid pulse characteristics. The alignment error between the measured displacement response peak center and the valley phase stabilizes within a certain range. Within ° crankshaft rotation angle, the deterministic management capability of the adjustment method for key parameters and logic paths was verified.

[0049] Example 5: In engine adaptation deployment sites with different exhaust pipe lengths, the system identifies the pressure wave propagation phase shift caused by exhaust pipe geometry parameters and performs a pre-calibration step. Under cold operating conditions that maintain stable speed, it acquires the exhaust valve opening trigger signal and the pressure peak signal at the back pressure adjustment actuator, and extracts the original time interval between the two signals. At the same time, the exhaust temperature is obtained. And according to the formula Determine the speed of propagation ,in, The propagation speed is expressed in m / s. Exhaust temperature, in units of The system combines the preset physical length of the flow channel Calculate physical delay components ,in, For physical time delay components, The physical length of the flow channel, measured over the original time interval. Subtract physical delay component Determine the amount of hysteresis compensation ,in, The original time interval, This is the hysteresis compensation amount. The data is stored in the memory and used to compensate for time delay deviations, so that the start time of the back pressure regulating actuator is locked at the starting phase point of the fluid circulation overlap valley range.

[0050] When the fluid discharge channel experiences increased flow resistance due to particulate matter buildup inside the carrier, the system initiates a baseline reconstruction step to correct the adjustment command. The processing unit then... At the end of the h monitoring cycle, the average static pressure in the fluid discharge channel is collected under low engine flow conditions and defined as the current resistance reference value. Using the formula Calculate the cumulative drag drift rate ,in, The cumulative drag drift rate, This is the current resistance benchmark value. The initial value of the clean carrier resistance, when the cumulative resistance drift rate... Exceeding the preset When the warning threshold is reached, the system determines the drift rate based on the cumulative resistance. The correction ratio of the advance of the target adjustment command is increased to compensate for the pressure wave distortion caused by the reduction of the local volume of the flow channel. The change of the physical state of the flow channel is followed by periodic resistance detection and window parameter correction, and the peak center of the actuator displacement response and the phase of the pulse wave trough are locked in the entire life cycle of the flow channel.

[0051] Example 6: During the parameter calibration process of the new batch of post-treatment system assembly line, in order to correct the influence of the difference in valve seat surface roughness caused by different casting processes on the urea crystal removal efficiency, the method executes the amplitude of the high-frequency micro-oscillation signal. With frequency The optimization calibration procedure is initiated in a static flow field environment after engine shutdown. The processing unit drives the back pressure regulation actuator to generate mechanical micro-vibrations within the permissible action window, and the frequency... by Hz is the step size from Hz increases to Hz, while simultaneously using a high-frequency pressure sampling link to monitor the standard deviation of back pressure fluctuations within the flow channel. When the back pressure fluctuation standard deviation achieve The system stops increasing the frequency and records the current frequency critical value when the global fluctuation threshold of kPa is reached. The system also records the transient peak current at the beginning of the displacement under each frequency gradient. The attenuation slope is used to determine The decay rate is the highest and The frequency point below the threshold value is the clearing resonance point of this batch of back pressure regulating actuators. .

[0052] By filling in the acquired resonance characteristic data, the system generates a control parameter matrix adapted to the physical hardware. During continuous operation after urea injection, the transient peak current of the acquired drive current signal at the initial stage of displacement is measured. Exceeding the initial current reference value When the value is %, the processing unit provides the target adjustment command within the overlapping valley range of the fluid circulation, and the superimposed amplitude is the command width. % and frequency is The high-frequency micro-oscillation signal, and the data monitoring results show transient peak current. exist Within the oscillation period of s, the current returns to the normal reference range corresponding to the initial current reference value, and the offset of the back pressure regulating actuator relative to the starting point stabilizes at the corresponding time. Within milliseconds, this calibration procedure eliminates fluctuations in crystal removal efficiency caused by manufacturing tolerances by parametrically extracting the dynamic characteristics of the actuator, maintaining back pressure regulation and a low-friction response state of the actuator movement throughout the entire life cycle of the flow channel.

[0053] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A method for dynamically adjusting the back pressure of a waste gas aftertreatment channel, characterized in that, Includes the following steps: Step S101: Obtain the phase reference signal of the fluid supply source and establish the phase mapping relationship between the fluid circulation stroke and the phase reference signal to determine the phase reference reference for back pressure regulation; Step S102: Real-time acquisition of pressure signals in the fluid discharge channel, and capture of instantaneous peak and valley values ​​of pressure signals in each phase cycle; Step S103: Use the instantaneous peak value minus the instantaneous valley value to determine the pulse range of the current cycle, calculate the rate of change of the pulse range between two adjacent cycles, and determine the range variability feedforward factor based on the rate of change of the pulse range. Step S104: Based on the operating frequency signal of the fluid supply source and the system load parameters, identify the fluid circulation overlap valley range in the pressure signal, and define the fluid circulation overlap valley range as the action allowable window of the back pressure regulating actuator. Step S105: Extract the envelope mean of the pressure signal and use it as the pressure feedback signal. Perform proportional-integral-derivative calculation based on the deviation between the pressure feedback signal and the target pressure value to determine the reference amplitude of the adjustment command. Step S106: When the rate of change of the pulse range exceeds the preset change threshold, the range rate feedforward factor is used to perform gain compensation on the reference amplitude in order to determine the target adjustment command. Step S107: Drive the back pressure regulating actuator to perform displacement action according to the target regulation command within the action allowable window, so that the peak moment of the displacement response of the back pressure regulating actuator is locked within the fluid circulation overlap valley range.

2. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 1, characterized in that, Step S107 further includes a step of correcting the adjustment phase by monitoring local disturbances within the action allowable window: extracting the pressure signal change rate within the action allowable window, identifying the pressure characteristic wave caused by the action of the back pressure regulating actuator; when the frequency of the pressure characteristic wave exceeds a preset value... When the Hz interference threshold is reached, the opening time of the action allowable window is determined to lag behind the starting point of the fluid circulation overlap valley interval; based on the offset of the pressure characteristic wave relative to the starting point, the advance of the target adjustment command is corrected online so that the response time of the displacement action is aligned with the phase center of the fluid circulation overlap valley interval.

3. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 2, characterized in that, In step S104, the method for identifying the overlapping valley interval of fluid circulation includes: acquiring the operating frequency signal and energy input parameters of the fluid supply source; retrieving a preset pressure pulse mapping spectrum based on the operating frequency signal and energy input parameters to determine the phase distribution characteristics of pressure fluctuation under the current operating condition; wherein, the pressure pulse mapping spectrum is pre-established by recording the valley distribution patterns of pressure signals corresponding to different frequency and load combinations under calibrated operating conditions; and defining the continuous phase region in the phase distribution characteristics where the pressure value is lower than the preset energy threshold as the overlapping valley interval of fluid circulation.

4. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 3, characterized in that, In step S106, the logic for determining the target adjustment command follows the following formula: ,in, Adjustment instructions for the target. As the reference amplitude, The pulse range of the current period. The pulse range of the previous cycle. This is the preset feedforward compensation coefficient.

5. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 1, characterized in that, After step S107, the method further includes a step of performing a mechanical health diagnosis on the back pressure regulating actuator: acquiring the drive current signal of the back pressure regulating actuator when it performs an action within the action allowable window; Extract the transient peak current of the drive current signal at the beginning of the displacement action; when the transient peak current is within a preset range... When the transient peak current shows a monotonically increasing trend within the h monitoring period, the deviation rate of the transient peak current relative to the initial current reference value is calculated, and the wear condition of the internal transmission components of the back pressure regulating actuator is evaluated based on the deviation rate.

6. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 1, characterized in that, In step S103, the pulse range is also used to correct the width of the action allowable window: when the pulse range increases and exceeds the first range threshold, the phase range of the action allowable window is shrunk; when the pulse range decreases and is below the second range threshold, the phase range of the action allowable window is expanded.

7. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 1, characterized in that, In step S102, a high-frequency pressure sampling link is used when acquiring the pressure signal, and the sampling frequency is set to the highest main frequency of the fluid circulation stroke. More than twice as high, to capture instantaneous peaks and troughs.

8. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 1, characterized in that, In step S107, the displacement action of the back pressure regulating actuator adopts a segmented step adjustment logic: the total displacement is determined according to the target adjustment command; the total displacement is decomposed into multiple step increments; the step increments are executed sequentially within multiple consecutive action allowable windows until the total displacement is reached.

9. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 5, characterized in that, Mechanical health diagnosis also includes a channel flow resistance monitoring step: extracting the pressure reference value at the instantaneous trough of the pressure signal; monitoring the cumulative drift of the pressure reference value over operating time; and generating a maintenance warning signal for the fluid discharge channel when the increase in the pressure reference value exceeds the preset resistance alarm threshold.

10. The method for dynamic adjustment of back pressure in a waste gas aftertreatment channel according to claim 1, characterized in that, This includes emergency control procedures: continuously monitoring the effectiveness of the phase reference signal; When the phase reference signal is determined to be lost, the phase-locked adjustment logic based on the phase mapping relationship is exited, and the backup control mode of full-phase adjustment based on the envelope mean of the pressure signal is switched.

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