CN-121993595-A - Control method for torque conversion power output of excavator

CN121993595ACN 121993595 ACN121993595 ACN 121993595ACN-121993595-A

Abstract

The invention relates to a control method for torque conversion power output of an excavator, which comprises the steps of collecting oil temperature, input rotating speed, output rotating speed and locking state of a torque converter according to a control period, comparing a difference value between the input rotating speed and the output rotating speed with a rotating speed difference threshold value, judging a slip or locking state by combining the locking state, accumulating corresponding state duration, setting a thermal limit with upper and lower limits on the slip state, deducting a heat reduction limit on the slip state according to the duration and the oil temperature rising speed, returning the heat reduction limit on the slip state according to the duration and the oil temperature falling speed, determining the oil temperature rising speed by the oil temperature change quantity of adjacent control periods, setting a first threshold value to be larger than a second threshold value, improving the locking duty ratio when the thermal limit is not higher than the second threshold value, periodically locking/unlocking to limit continuous slip duration, reducing the locking duty ratio when the thermal limit is not lower than the first threshold value, maintaining the current locking duty ratio when the thermal limit is between the two threshold values, and finally outputting a locking control instruction.

Inventors

LIU MINGTAO
XU GANG
ZHENG ENHUA
Qiang Huaxia

Assignees

山东恒旺重工机械设备有限公司

Dates

Publication Date: 20260508
Application Date: 20260306

Claims (10)

1. The control method is suitable for a power transmission system with a torque converter and a locking unit, and is characterized in that the control unit collects the oil temperature, the input rotating speed, the output rotating speed and the locking state of the torque converter according to a control period; The control unit sets a thermal limit which has an upper limit and a lower limit, deducts the thermal limit according to duration time and oil temperature rising speed in a sliding state, and supplements the thermal limit back according to duration time and oil temperature falling speed in a locking state, wherein the oil temperature rising speed and the oil temperature falling speed are determined by oil temperature change amounts in adjacent control periods; The control unit sets a first threshold value larger than a second threshold value, improves the locking duty ratio and periodically locks/unlocks to limit the continuous sliding time when the thermal limit is not higher than the second threshold value, reduces the locking duty ratio when the thermal limit is not lower than the first threshold value, and keeps the current locking duty ratio when the thermal limit is between the two threshold values, and outputs a locking control instruction.
2. The method for controlling torque conversion power output of an excavator according to claim 1, wherein the control unit releases the lock and resumes the lock after a predetermined pulse period when the thermal limit is not lower than a first threshold and the torque converter is continuously locked for a predetermined steady period, and corrects the thermal limit buckling strength in a subsequent slip state or the thermal limit restoration strength in a locked state according to the oil temperature change amplitude before and after the pulse.
3. The method for controlling torque conversion power output of an excavator according to claim 1 is characterized in that the control unit counts switching times of a slip state and a locking state in a preset time window, enters vibration suppression control when the switching times reach a preset entering threshold value, keeps a locking duty ratio unchanged, keeps slip state keeping time not smaller than a preset slip keeping time threshold value and keeps the locking state keeping time not smaller than the preset locking keeping time threshold value, temporarily increases an interval between a first threshold value and a second threshold value, exits the vibration suppression control when the switching times are reduced to a preset exiting threshold value, and suspends locking duty ratio adjustment based on a thermal quota during vibration suppression control, and resumes after exiting.
4. The control method for torque conversion power output of an excavator according to claim 1, wherein the control unit sets a thermal shock memory amount, accumulates the thermal shock memory amount when the thermal limit is not higher than a second threshold value to trigger the improvement of a locking duty ratio and the periodic locking/unlocking, temporarily adjusts an upper limit of the thermal limit and synchronously adjusts the first threshold value and the second threshold value when the thermal shock memory amount reaches a preset value, and clears the thermal shock memory amount and restores the upper limit and the threshold value when the accumulated locking duration reaches a preset restoration duration and the oil temperature satisfies a cooling criterion.
5. The method for controlling torque conversion power output of an excavator according to claim 3, wherein when entering the vibration suppression control, the threshold interval increment is selected as one of preset gears according to a switching frequency peak value in a preset backtracking period before entering, when entering the vibration suppression control, if entering conditions are met again, the threshold interval increment is switched to a next preset gear and the interval between a first threshold and a second threshold is updated, and when the preset backtracking conditions are met, backtracking is allowed to be carried out to the previous preset gear.
6. The method for controlling torque conversion power output of an excavator according to claim 3, wherein the control unit sets a release condition for state switching during vibration suppression control, wherein the slip state is switched from a slip state to a lock state so that a slip holding time is not less than a preset slip holding time threshold and the switching times are not more than a preset fall-back threshold, and the lock state is switched from the lock state to the slip state so that the lock holding time is not less than the preset lock holding time threshold and the switching times are not more than the preset fall-back threshold.
7. The method for controlling torque conversion power output of an excavator according to claim 5, wherein the preset gears are mapped according to intervals of peak values of switching times, each preset gear corresponds to a threshold interval by a large amount, the intervals of the peak values are determined firstly when vibration suppression control is performed, then the intervals of the corresponding preset gears are selected, and the intervals of the first threshold value and the second threshold value are updated.
8. The method for controlling torque conversion power output of an excavator according to claim 5, wherein the re-meeting of the entering condition during vibration suppression control includes continuously meeting the entering threshold value for a preset number of times in a preset time window, switching the threshold interval increment to a next preset gear when the entering threshold value is met, and setting a preset holding time period, wherein the back to the previous preset gear is prohibited during the holding time period.
9. The control method for torque conversion power output of an excavator according to claim 6, wherein the control unit sets a one-way holding time period during vibration suppression control, the one-way holding time period being one of a plurality of preset holding time long gear positions, when switching from a slipping state to a locking state is completed, switching from the locking state to the slipping state is prohibited within the one-way holding time period, and when switching from the locking state to the slipping state is completed, switching from the slipping state to the locking state is prohibited within the one-way holding time period.
10. The method for controlling torque conversion power output of an excavator according to claim 9 is characterized by dynamically adjusting the one-way holding time according to the switching times of the slip state and the locking state in a first time window after expiration of the one-way holding time, switching the one-way holding time to the next preset holding time when the switching times are still larger than a preset adjustment threshold value, and switching the one-way holding time to the previous preset holding time or keeping unchanged when the switching times are not larger than the preset adjustment threshold value.

Description

Control method for torque conversion power output of excavator Technical Field The invention relates to the technical field of power transmission control of engineering machinery, in particular to a control method for torque conversion power output of an excavator. Background The key point of the scheme is to set locking conditions based on gear and rotation speed difference, slip ratio or rotation speed ratio parameters, control a turbine locking clutch to lock when preset conditions are met, and lock when the gear reaches preset gear and the rotation speed difference or slip ratio or rotation speed ratio meets preset conditions of the corresponding gear. Although the scheme realizes automatic locking, the scheme still stays in a static threshold control level based on a rotating speed relation, locking and unlocking decisions mainly depend on a comparison relation between an instantaneous detection value and a pre-stored parameter, and systematic management on a thermal state evolution process, a slip duration accumulation effect and a locking and unlocking oscillation behavior of the torque converter is lacking, so that obvious defects still exist under a complex working condition. According to the method, a dynamic constraint mechanism between slip heating and locking recovery is not established, heat accumulation caused by continuous slip is not quantitatively managed, locking or unlocking is only carried out when the rotating speed condition is met, the influence of slip duration on the oil temperature of the torque converter and the thermal load of the clutch cannot be identified, and the problem that the temperature rise is aggravated due to overlong slip time under the working conditions of high load and long-time low-speed operation is easily caused. The locking condition of the scheme is mainly developed around the gear and the rotation speed difference or the slip ratio, the change trend of the oil temperature is not utilized, and analysis of the rising speed or the falling speed of the oil temperature is not introduced, so that the control strategy cannot be dynamically corrected according to the real-time thermal change trend, and the original preset parameters may lose adaptability and influence the control effect when the environment temperature changes or the oil state changes. Although the document proposes multi-condition locking judgment, the control logic is still of a single judgment triggering type structure, the oscillation problem caused by repeated switching of locking and unlocking around a threshold value is not considered, a suppression mechanism for frequent locking and unlocking behaviors is lacked, repeated combination and separation of a locking clutch can occur under the condition of load fluctuation or slight fluctuation of rotating speed, impact, shaking and comfort are reduced, and mechanical abrasion is increased. The technology does not establish a history memory mechanism, does not carry out accumulated statistics on the multi-triggering locking limiting behaviors, and does not carry out grading adjustment on the control strategy according to the repeated triggering times, so that the long-term thermal shock or continuous oscillation trend cannot be identified, the control strategy lacks progressive strengthening or stepping adjustment capability, and stable output is difficult to maintain in complex operation circulation. The gear shifting and locking strategy in the document is mainly designed around a rotating speed point, and the influence of the accelerator opening on the gear shifting point is considered, but the sliding behavior is not restrained from the thermal management angle, and similar thermal limit or thermal shock memory variables are not set to comprehensively integrate the sliding energy consumption and locking recovery process. Disclosure of Invention The invention aims to provide a control method for torque conversion power output of an excavator, so as to solve part of defects and shortcomings pointed out in the background art. The control method for torque conversion power output of the excavator comprises the following steps that the control method is suitable for a power transmission system with a torque converter and a locking unit, and is executed by the control unit, wherein the control unit collects the oil temperature, the input rotating speed, the output rotating speed and the locking state of the torque converter according to a control period; The control unit sets a thermal limit which has an upper limit and a lower limit, deducts the thermal limit according to duration time and oil temperature rising speed in a sliding state, and supplements the thermal limit back according to duration time and oil temperature falling speed in a locking state, wherein the oil temperature rising speed and the oil temperature falling speed are determined by oil temperature change amounts in adjacent control periods; The control unit sets a first threshol