CN-121857825-B - Dynamic back pressure adjusting method for exhaust gas aftertreatment runner

CN121857825BCN 121857825 BCN121857825 BCN 121857825BCN-121857825-B

Abstract

The invention relates to the technical field of non-electric variable control or regulation systems, and discloses a method for dynamically regulating the backpressure of an exhaust gas aftertreatment runner, which comprises the steps of obtaining a supply source phase reference signal and establishing a cyclic mapping; the method comprises the steps of extracting the pulse range change rate of a pressure signal of a fluid channel to determine a feedforward factor, determining a trough section of the pressure signal as an action window, determining a reference amplitude based on feedback deviation and compensating by utilizing the feedforward factor, determining a target regulating instruction, driving a regulating mechanism to displace in the action window to lock a response peak value in the trough section.

Inventors

ZHANG YUXU
PENG JIA
XIE SHOUYI

Assignees

马瑞利汽车零部件(长沙)有限公司

Dates

Publication Date: 20260508
Application Date: 20260317

Claims (10)

1. The method for dynamically adjusting the back pressure of the exhaust gas aftertreatment runner is characterized by comprising the following steps of: Step S101, a phase reference signal of a fluid supply source is obtained, and a phase mapping relation between a fluid circulation stroke and the phase reference signal is established so as to determine a phase reference standard of back pressure adjustment; Step S102, collecting pressure signals in a fluid discharge channel in real time, and capturing instantaneous peaks and instantaneous valleys of the pressure signals in each phase cycle period; step S103, subtracting an instantaneous valley value from an instantaneous peak value to determine the pulse range of the current period, calculating the change rate of the pulse range of two adjacent periods, and determining a range change rate feedforward factor according to the change rate of the pulse range; step S104, identifying a fluid circulation overlapping valley interval in the pressure signal according to the operation frequency signal of the fluid supply source and the system load parameter, and defining the fluid circulation overlapping valley interval as an action permission window of the back pressure regulating executing mechanism; Step S105, extracting an envelope mean value of the pressure signal and taking the envelope mean value as a pressure feedback signal, and performing proportional-integral-derivative calculation based on the deviation between the pressure feedback signal and a target pressure value to determine a reference amplitude of the adjustment instruction; step S106, under the working condition that the change rate of the pulse range exceeds a preset change threshold, performing gain compensation on the reference amplitude by utilizing a range rate feedforward factor to determine a target adjustment instruction; And step S107, driving the back pressure adjusting executing mechanism to execute displacement action in the action allowing window according to the target adjusting instruction, so that the peak time of the displacement response of the back pressure adjusting executing mechanism is locked in the fluid circulation overlapping valley interval.
2. The method according to claim 1, wherein the step S107 further comprises the step of correcting the adjustment phase by monitoring the local disturbance in the action permission window, wherein the rate of change of the pressure signal in the action permission window is extracted, the pressure characteristic wave caused by the action of the back pressure adjustment actuator is identified, and when the frequency of the pressure characteristic wave exceeds a preset value And according to the offset of the pressure characteristic wave relative to the starting point, on-line correcting the issuing advance of the target regulating command to align the response time of the displacement action with the phase center of the fluid circulation overlapping valley interval.
3. The method for dynamically adjusting back pressure of an exhaust gas aftertreatment flow channel according to claim 2, wherein in step S104, the method for identifying a fluid circulation overlapping valley interval comprises the steps of obtaining an operation frequency signal and an energy input parameter of a fluid supply source, searching a preset pressure pulse mapping map according to the operation frequency signal and the energy input parameter, determining a phase distribution characteristic of pressure fluctuation under a current working condition, wherein the pressure pulse mapping map is pre-established by recording pressure signal valley distribution rules corresponding to different frequency and load combinations under a calibration working condition, and defining a continuous phase region with a pressure value lower than a preset energy threshold value in the phase distribution characteristic as the fluid circulation overlapping valley interval.
4. A method of dynamic adjustment of exhaust aftertreatment flow channel backpressure according to claim 3, wherein in step S106 the logic for determining the target adjustment command follows the formula: , wherein, In order to adjust the instructions for the purposes, As the reference amplitude value, Is the pulse of the current period is extremely bad, The pulse for the previous cycle is very poor, Is a preset feedforward compensation coefficient.
5. The method for dynamically adjusting back pressure of exhaust gas aftertreatment flow channel according to claim 1 further comprising the step of performing mechanical health diagnosis on the back pressure adjusting actuator after step S107, wherein the step of collecting driving current signals of the back pressure adjusting actuator when the back pressure adjusting actuator performs an action within an action permission window, the step of extracting transient peak current of the driving current signals in an initial stage of moving in place, and the step of detecting that the transient peak current is within a preset range And h, calculating the offset rate of the transient peak current relative to the initial current reference value when the monotonically rising trend is shown in the monitoring period, and evaluating the abrasion state of the transmission component in the back pressure adjusting executing mechanism according to the offset rate.
6. The method according to claim 1, wherein in step S103, the pulse margin is further used to correct the width of the motion permission window, wherein the phase range of the motion permission window is narrowed when the pulse margin increases and exceeds a first margin threshold, and the phase range of the motion permission window is widened when the pulse margin decreases and falls below a second margin threshold.
7. The method according to claim 1, wherein in step S102, a high-frequency pressure sampling link is used to collect the pressure signal, and the sampling frequency is set to be the highest main frequency of the fluid circulation path More than one time to capture instantaneous peaks and instantaneous valleys.
8. The method for dynamically adjusting back pressure of an exhaust gas aftertreatment flow passage according to claim 1, wherein in step S107, the displacement action of the back pressure adjusting actuator adopts a stepwise step adjustment logic, wherein the total displacement is determined according to a target adjustment command, the total displacement is decomposed into a plurality of step increments, and the step increments are sequentially executed in a continuous plurality of action permission windows until the total displacement is reached.
9. The method according to claim 5, wherein the mechanical health diagnosis further comprises a channel flow resistance monitoring step of extracting a pressure reference value of the pressure signal at the instant valley, monitoring an accumulated drift amount of the pressure reference value with the running time, and generating a maintenance early warning signal of the fluid discharge channel when an increase amount of the pressure reference value exceeds a preset resistance alarm threshold.
10. The method for dynamically adjusting the back pressure of an exhaust gas aftertreatment flow passage according to claim 1 is characterized by comprising the emergency control step of continuously monitoring the validity state of a phase reference signal, and when the phase reference signal is determined to be lost, exiting a phase locking adjustment logic based on a phase mapping relation, and switching to a backup control mode of performing full-phase adjustment based on the envelope mean value of a pressure signal.

Description

Dynamic back pressure adjusting method for exhaust gas aftertreatment runner Technical Field The invention belongs to the technical field of non-electric variable control or regulation systems, and particularly relates to a dynamic back pressure regulating method for an exhaust gas aftertreatment runner. Background In the prior art, an average value of fluid signals is generally collected as a feedback signal for a fluid system with periodic pressure pulses, closed-loop adjustment is implemented by combining a control algorithm, the pressure in an exhaust runner is severely fluctuated along with a crank angle due to the fact that the exhaust process of an internal combustion engine presents periodic pulse characteristics, so that the exhaust period is divided into a pressure peak value area corresponding to an exhaust stroke and a pressure valley value area corresponding to ventilation overlapping, the control strategy evolution faces a bottleneck, for example, patent of the utility model with an issued publication number of CN223648643U discloses an automatic back pressure valve pressure adjusting device, a stepping motor drives a first connecting rod to rotate, a screw thread is matched to drive a second connecting rod to displace to change the compression amount of a pressure spring, and the closed-loop automatic adjustment is based on pressure sensor feedback data. In the periodic alternating flow field, the prior art often ignores the time domain distribution characteristic of exhaust pulse, if an executing mechanism executes opening adjustment action during the pressure peak of the exhaust stroke, a valve plate bears transient fluid impact force, so that a driving mechanism is induced to generate high-frequency mechanical vibration to accelerate the fatigue loss of a speed reduction gear set, in order to maintain control stability, a filtering algorithm is generally adopted in the industry to extract the envelope mean value of controlled fluid pressure, but the increasing of filtering depth can generate signal time domain lag, so that a controller of a control system cannot sense the step change of the energy level of the flow field in real time, finally, the system generates technical contradiction which is difficult to compromise between dynamic response speed and adjustment stability, and even if the static prediction model is tried to be used for compensating the action advance of the executing mechanism, the pressure wave conduction speed is not linearly changed due to the action advance of the exhaust temperature fluctuation, and the preset adjustment phase is difficult to be accurately locked at a low energy window of the flow field due to resistance drift generated by a mechanical part in long-term operation. Therefore, on the premise of ensuring the response speed of the system, the accurate physical coincidence of the adjustment action and the low-energy interval in the controlled variable signal is realized, and the phase offset caused by the change of the environmental parameters and the mechanical characteristics is dynamically eliminated, so that the invention is the technical problem to be solved. Disclosure of Invention The invention provides a dynamic back pressure regulating method for an exhaust gas aftertreatment runner, which comprises the following steps: Step S101, a phase reference signal of a fluid supply source is obtained, and a phase mapping relation between a fluid circulation stroke and the phase reference signal is established so as to determine a phase reference standard of back pressure adjustment; Step S102, collecting pressure signals in a fluid discharge channel in real time, and capturing instantaneous peaks and instantaneous valleys of the pressure signals in each phase cycle period; step S103, subtracting an instantaneous valley value from an instantaneous peak value to determine the pulse range of the current period, calculating the change rate of the pulse range of two adjacent periods, and determining a range change rate feedforward factor according to the change rate of the pulse range; step S104, identifying a fluid circulation overlapping valley interval in the pressure signal according to the operation frequency signal of the fluid supply source and the system load parameter, and defining the fluid circulation overlapping valley interval as an action permission window of the back pressure regulating executing mechanism; Step S105, extracting an envelope mean value of the pressure signal and taking the envelope mean value as a pressure feedback signal, and performing proportional-integral-derivative calculation based on the deviation between the pressure feedback signal and a target pressure value to determine a reference amplitude of the adjustment instruction; step S106, under the working condition that the change rate of the pulse range exceeds a preset change threshold, performing gain compensation on the reference amplitude by utilizing a range rate fe