Commercial vehicle AMT dynamic downshifting and gear shifting control method and system and medium
By employing clutch torque characteristic curves and a linear progressive engagement method in commercial vehicle AMT transmissions, fast and smooth gear shifting has been achieved, solving the problems of long shifting time and poor comfort in traditional methods, and improving power and driving experience.
Patent Information
- Application Number
- CN202511766295.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-01-09
AI Technical Summary
Existing AMT transmissions for commercial vehicles suffer from problems such as long shift times, power interruption, and poor driving comfort during dynamic downshifting. In particular, the traditional two-clutch engagement method leads to large fluctuations in engine speed, input shaft speed mismatch, and long clutch engagement time.
The system employs a clutch torque characteristic curve and a linear progressive engagement method. By pre-storing the clutch torque characteristic curve and the engagement gear speed of each gear through the transmission TCU, the system controls the clutch to reach the initial target position and deepens the engagement according to a preset slope. After the engagement gear speed is synchronized with the target gear, the actuator is activated to complete the gear shift.
It shortens shift time, reduces power interruption, improves driving comfort and vehicle power, reduces engine speed fluctuations and mechanical wear, and optimizes the shifting process.
Smart Images
Figure CN121296694A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of AMT control technology, specifically relating to a control method, system and medium for dynamic downshifting and gear shifting in commercial vehicle AMT. Background Technology
[0002] AMT is short for Automated Mechanical Transmission.
[0003] In AMT control for commercial vehicles, speed synchronization during dynamic downshifting is a crucial aspect. Current technologies for downshifting in commercial vehicle AMT transmissions typically employ a two-stage clutch engagement method to maintain smoothness. Specifically, a deep clutch engagement rapidly increases the speeds of the input shaft, intermediate shaft, and engagement gear ring; then, the clutch disengages, waiting for the input shaft speed to drop to a downshift window slightly above the engagement sleeve speed; finally, at the synchronized speed window, the actuator solenoid valve is activated, pushing the engagement sleeve to mesh with the target gear gear ring, and the clutch is fully engaged again after the shift is complete.
[0004] However, this method of synchronizing downshifting speed in commercial vehicle AMT transmissions with two-stage clutch engagement has the following drawbacks: First, during the first clutch engagement, in order to quickly increase the speed, the clutch is in a deep engagement state, resulting in large fluctuations in engine speed; second, if the clutch disengages slowly, the input shaft speed may exceed the shift window, requiring waiting for the speed to drop, thus prolonging the shift time; finally, after the shift is completed, the time required for the clutch to go from complete disengagement to complete engagement is relatively long, resulting in power interruption and shift jerking, affecting driving comfort and power.
[0005] Therefore, there is an urgent need for a control method that can shorten shift time and improve shift comfort. Summary of the Invention
[0006] In a first aspect, embodiments of this application provide a control method for dynamic downshifting in an AMT (Automated Manual Transmission) system for commercial vehicles, comprising the following steps: S1. The transmission TCU pre-stores clutch torque characteristic curves that represent the engine torque values that the clutch can transmit at different engagement positions; S2. The transmission TCU pre-records and stores the rotational speed of each gear engagement sleeve; S3. During vehicle operation, the transmission TCU waits and confirms that the AMT transmission has disengaged and returned to neutral. S4. In response to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position. S5. The transmission TCU controls the clutch to deepen engagement from the initial target position according to a preset slope, so as to increase the speed of the input shaft and the engagement gear ring; S6. The rotational speed of the gear ring is detected by the speed sensor, and the detected speed is compared with the rotational speed of the gear sleeve of the target gear in the pre-stored gear position. When the rotational speed of the gear ring reaches the shift window of the rotational speed of the gear sleeve of the target gear position, a speed synchronization signal is generated. S7. In response to the generated speed synchronization signal, the transmission TCU activates the actuator solenoid valve, pushing the engagement sleeve to engage with the engagement gear ring of the target gear, thus completing the gear shifting operation.
[0007] Furthermore, the specific steps of step S1 are as follows: S11. Determine the original data of multiple clutch engagement positions and corresponding clutch transmission torque values through test bench calibration; S12. Quantify the clutch engagement position in the original data into a percentage relative to the total clutch travel; S13. Fit the quantified percentage form of the clutch engagement position to generate a continuous clutch torque transmission characteristic curve that represents the relationship between the percentage of the clutch position and the clutch transmitted torque value. S14. The clutch torque transmission characteristic curve is stored in the non-volatile memory of the transmission TCU. The clutch torque transmission characteristic curve is generated through test bench calibration and data fitting, ensuring the accuracy and reliability of clutch control; the clutch engagement position is quantified as a percentage and stored for easy real-time retrieval and calculation, improving the system's response speed.
[0008] Furthermore, the specific steps of step S2 are as follows: S21. Calculate the speed ratio of each gear based on the gear ratio of each gear in the transmission; S22. Taking each gear as the target gear, and based on the engine speed and the speed ratio of the target gear, calculate the target gear combined with the gear sleeve speed according to the following formula. :
[0009] in, Engine speed, The gear ratio for the target gear; S23. The speed of each gear and its corresponding engagement sleeve is stored in the transmission TCU as a data table. The target gear engagement sleeve speed is calculated based on the engine speed and gear ratio, ensuring the accuracy of speed matching during gear shifting; storing the speed information of each gear in the form of a data table facilitates quick querying and comparison, improving the system's operating efficiency.
[0010] Furthermore, the specific steps of step S3 are as follows: S31. The transmission TCU responds to the downshift command and controls the shift actuator to switch the current gear to the neutral position; S32. The transmission TCU confirms that the shift mechanism is in neutral via a position sensor, determining that the AMT transmission is in neutral disengagement mode. Confirming the shift mechanism is in neutral via a position sensor ensures the accuracy and reliability of shifting operations; timely response to downshift commands and confirmation of disengagement reduces delays during the shifting process.
[0011] Furthermore, the specific steps of step S4 are as follows: S41. Based on the engine's moment of inertia Clutch rotational inertia and the rotational inertia of the target gear of the transmission The percentage of the initial target position is calculated using the following formula. : Among them, the function Obtained by fitting experimental data; S42. Query the clutch torque transmission characteristic curve to find the percentage relative to the initial target position. The corresponding clutch torque value; S43. Based on the found clutch transmission torque value, the clutch is driven to the initial target position by controlling the duty cycle of the clutch booster cylinder solenoid valve. The accuracy of the clutch engagement starting point is ensured by calculating the initial target position based on the rotational inertia of the engine and transmission; precise clutch control is achieved by querying the torque transmission characteristic curve and controlling the solenoid valve duty cycle.
[0012] Furthermore, the specific steps of step S5 are as follows: S51. Based on engine reference torque The gear ratio of the target gear and current throttle percentage The slope of the clutch engagement process can be calculated using the following formula. :
[0013] in, These are constants calibrated based on the system's moment of inertia; S52. Starting from the initial target position, control the clutch to move according to the slope. The linear deepening of the interaction over time causes the input shaft speed to increase according to the following formula:
[0014] in, This represents the input shaft speed at time t. This represents the initial input shaft speed. By calculating the clutch engagement slope based on engine torque, gear ratio, and throttle percentage, dynamic optimization of the clutch engagement process is achieved; by increasing the input shaft speed through a linear deepening engagement method, the accuracy and stability of speed synchronization are ensured.
[0015] Furthermore, the specific steps of step S6 are as follows: S61. The rotational speed of the engaged gear ring is collected in real time via a speed sensor. ; S62. Retrieve the engagement gear speed of the target gear from the stored data table. ; S63. Calculate the speed difference using the following formula. : ; The speed difference Synchronization tolerance with preset The synchronization tolerance was compared. Set according to the gear ratio; S64. When the speed difference Less than or equal to the synchronization tolerance When the shift window is reached, a speed synchronization signal is generated. By collecting speed data in real time and calculating the speed difference, accurate speed synchronization is ensured; and by setting a synchronization tolerance based on the gear ratio, the system's adaptability and robustness are improved.
[0016] Furthermore, the specific steps of step S7 are as follows: S71. The transmission TCU sends an activation command to the actuator solenoid valve; S72. The actuator solenoid valve responds to the activation command and drives the engagement gear sleeve to move axially and engage with the engagement gear ring of the target gear position; S73. After confirming successful gear engagement, the clutch is fully engaged to restore power transmission. Activating the solenoid valve and confirming successful gear engagement ensures efficient and reliable gear shifting; immediately fully engaging the clutch after successful gear engagement reduces power interruption time.
[0017] Secondly, embodiments of this application also provide a control system for dynamic downshifting in an AMT (Automated Manual Transmission) system for commercial vehicles, comprising: The data storage module is used to pre-store the clutch torque transmission characteristic curves that characterize the engine torque values that the clutch can transmit at different engagement positions, as well as the engagement sleeve speeds of each gear. The status confirmation module is used to wait for and confirm that the AMT transmission has disengaged and returned to neutral while the vehicle is in motion; The clutch control module is used to respond to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position; further, it controls the clutch to deepen engagement from the initial target position according to a preset slope, so as to increase the speed of the input shaft and the engagement gear ring. The speed synchronization judgment module is used to detect the speed of the engagement gear ring through a speed sensor, and compare the detected speed with the speed of the engagement sleeve of the target gear in the pre-stored gear position. When the speed of the engagement gear ring reaches the shift window of the engagement sleeve speed of the target gear, a speed synchronization signal is generated. The gear shifting module is used to activate the solenoid valve of the actuator in response to the generated speed synchronization signal, which pushes the engagement sleeve to engage with the engagement gear ring of the target gear to complete the gear shifting operation.
[0018] Thirdly, embodiments of this application also provide a storage medium storing a computer program thereon, wherein when the computer program is executed by a processor, it implements the steps of the control method for dynamic downshifting and gear shifting of a commercial vehicle AMT as described in the first aspect.
[0019] As can be seen from the above technical solutions, this application has the following advantages: The control method, system, and medium for dynamic downshifting in commercial vehicle AMT provided in this application complete the downshifting operation with a single clutch engagement, avoiding the prolonged shifting time caused by two clutch engagements in traditional methods, thus improving shifting efficiency. The linear progressive clutch engagement method reduces the jerking sensation during shifting, improving driving comfort. Reduced clutch engagement time avoids power interruption, enhancing vehicle power. Precise control of clutch engagement position and speed synchronization reduces mechanical wear and malfunctions caused by improper clutch operation. The optimized shifting process reduces engine speed fluctuations, thereby lowering fuel consumption. Attached Figure Description
[0020] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a flowchart illustrating the control method for dynamic downshifting and gear shifting in a commercial vehicle AMT according to the present invention.
[0022] Figure 2 This is a schematic diagram of the control system for dynamic downshifting in an AMT (Automated Manual Transmission) for commercial vehicles according to the present invention. Detailed Implementation
[0023] The various embodiments of this disclosure will be described more fully in the following detailed description of the specific steps of the control method for dynamic downshifting in an AMT (Automated Manual Transmission) for commercial vehicles. This disclosure may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.
[0024] For example, AMT stands for Automatic Manual Transmission. In AMT control for commercial vehicles, speed synchronization during dynamic downshifting is a crucial aspect. Traditionally, commercial vehicle AMT transmissions typically employ a two-stage clutch engagement to achieve downshift speed synchronization, ensuring smooth operation. The specific process is as follows: first, a deep clutch engagement rapidly increases the speed of the input shaft, intermediate shaft, and engagement gear ring; then, the clutch disengages, waiting for the input shaft speed to drop to a shift window slightly higher than the engagement sleeve speed; finally, at the speed synchronization window, the solenoid valve is activated, pushing the engagement sleeve to mesh with the target gear gear ring, completing the shift, and then the clutch is fully engaged again.
[0025] However, this two-stage clutch engagement method has significant drawbacks: First, the deep engagement during the first engagement causes substantial fluctuations in engine speed; second, if the clutch disengages too slowly, the input shaft speed may exceed the shift window, requiring waiting for the speed to drop, thus prolonging the shift time; finally, the long time it takes for the clutch to fully engage after disengagement can easily lead to power interruption and shift jerking, severely impacting driving comfort and performance. Therefore, a new control method that can shorten shift time and improve shift comfort is urgently needed.
[0026] To address the aforementioned issues, this embodiment provides a control method for dynamic downshifting in commercial vehicle AMT (Automated Manual Transmission). It employs a combination of clutch torque characteristic curves and a linear progressive approach to optimize the shifting process, shorten shifting time, reduce power interruption, and improve shifting comfort and power.
[0027] 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.
[0028] Please see Figure 1 The diagram shows a flowchart of a control method for dynamic downshifting in a commercial vehicle AMT (Automated Manual Transmission) system, according to a specific embodiment. The method includes the following steps: S1. The transmission TCU pre-stores clutch torque characteristic curves that represent the engine torque values that the clutch can transmit at different engagement positions; It should be noted that by storing the clutch torque transmission characteristic curve, a data foundation is provided for the precise control of the clutch, ensuring the reliability and stability of the clutch engagement process. S2. The transmission TCU pre-records and stores the rotational speed of each gear engagement sleeve; It should be noted that by pre-storing the speed of each gear combined with the gear sleeve speed, an accurate reference value is provided for speed synchronization during gear shifting, thus improving the accuracy of gear shifting; S3. During vehicle operation, the transmission TCU waits and confirms that the AMT transmission has disengaged and returned to neutral. It should be noted that by confirming the gearbox's neutral state in real time while the vehicle is in motion, the timing of gear shifting is ensured to be accurate, thus avoiding incorrect operation during gear shifting. S4. In response to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position. It should be noted that controlling the clutch to reach the initial target position based on the torque transmission characteristic curve provides an accurate starting point for subsequent clutch engagement, reducing errors in the clutch engagement process. S5. The transmission TCU controls the clutch to deepen engagement from the initial target position according to a preset slope, so as to increase the speed of the input shaft and the engagement gear ring; It should be noted that by deepening the clutch engagement through a preset slope, linear and progressive control of the clutch engagement process is achieved, reducing shift jerking and improving shifting comfort. S6. The rotational speed of the gear ring is detected by the speed sensor, and the detected speed is compared with the rotational speed of the gear sleeve of the target gear in the pre-stored gear position. When the rotational speed of the gear ring reaches the shift window of the rotational speed of the gear sleeve of the target gear position, a speed synchronization signal is generated. It should be noted that by using a speed sensor to detect and combine the gear ring speed with the target speed, accurate judgment of speed synchronization is ensured, avoiding shifting failures caused by speed mismatch. S7. In response to the generated speed synchronization signal, the transmission TCU activates the actuator solenoid valve, which pushes the engagement sleeve to engage with the engagement ring of the target gear, thus completing the gear shifting operation; It should be noted that the system responds quickly to the speed synchronization signal to complete the gear shifting operation, and fully engages the clutch after confirming successful gear shifting to restore power transmission, thereby reducing power interruption time and improving vehicle performance.
[0029] This embodiment achieves precise clutch control and speed synchronization by storing the clutch torque characteristic curve and the rotational speed of the gear sleeves for each gear, thus solving the problems of long shifting time and poor comfort in traditional AMT.
[0030] Furthermore, as a refinement and extension of the specific implementation methods of the above embodiments, in order to fully illustrate the specific implementation process in this embodiment, another control method for dynamic downshifting and gear shifting in a commercial vehicle AMT is provided. Taking a heavy-duty commercial vehicle AMT transmission as the application object, the transmission contains 5 forward gears and the engine's maximum torque is 1500 N. m, the total clutch travel is 20mm, and dynamic downshifting is achieved through the control method provided in this application. The method includes the following steps: S1. The transmission TCU pre-stores clutch torque characteristic curves representing the engine torque values that the clutch can transmit at different engagement positions; the specific steps of step S1 are as follows: S11. Determine the original data of multiple clutch engagement positions and corresponding clutch transmission torque values through test bench calibration; For example, an experimental bench was built to simulate the actual driving conditions of a commercial vehicle. By adjusting the clutch engagement position, multiple sets of raw data on the clutch engagement position and the corresponding transmitted torque were collected. Some of the data are shown in Table 1 below: Table 1
[0031] S12. Quantify the clutch engagement position in the original data into a percentage relative to the total clutch travel; For example, the clutch engagement position is quantified as a percentage of the total stroke (total stroke 20mm), calculated as "engagement position / total stroke × 100%", and the quantified data is shown in Table 2 below: Table 2
[0032] S13. Fit the quantified percentage form of the clutch engagement position to generate a continuous clutch torque transmission characteristic curve that represents the relationship between the percentage of the clutch position and the clutch transmitted torque value. For example, the least squares method is used to fit the quantized data to generate a continuous clutch torque characteristic curve, with the curve equation being T=0.025P. 2 +3.2P-120 (where T is the transmitted torque and P is the position percentage). S14. Store the clutch torque transmission characteristic curve in the non-volatile memory of the transmission TCU; For example, the curve is stored in the non-volatile memory of the transmission TCU for real-time recall during the shifting process; It should be noted that the clutch torque characteristic curve was generated through test bench calibration and data fitting, which ensured the accuracy and reliability of clutch control; the clutch engagement position was quantified as a percentage and stored, which facilitates real-time retrieval and calculation, and improved the system response speed. S2. The transmission TCU pre-records and stores the rotational speeds of the gear sleeves engaged in each gear position; the specific steps of step S2 are as follows: S21. Calculate the speed ratio of each gear based on the gear ratio of each gear in the transmission; For example, the speed ratio is calculated based on the gear ratio of each gear in the transmission. The speed ratios of each gear in the transmission are shown in Table 3 below: Table 3
[0033] S22. Taking each gear as the target gear, and based on the engine speed and the speed ratio of the target gear, calculate the target gear combined with the gear sleeve speed according to the following formula. :
[0034] in, Engine speed, The gear ratio for the target gear; For example, suppose the current engine speed is... =1500r / min. The speed of each gear combined with the gear sleeve is calculated according to the formula. Part of the calculation process is as follows: Speed of gear sleeve in first gear: N1 = 1500 × 6.8 = 10200 r / min 3rd gear engagement speed: N3 = 1500 × 3.2 = 4800 r / min Speed of gear sleeve in 5th gear: N5 = 1500 × 1.5 = 2250 r / min S23. Store each gear and its corresponding engagement gear speed in the transmission TCU in the form of a data table; For example, the gear positions and their corresponding gear sleeve speeds are compiled into a data table and stored in the TCU. The complete data table is shown in Table 4 below: Table 4
[0035] It should be noted that the target gear combined with the gear sleeve speed is calculated based on the engine speed and gear ratio, which ensures the accuracy of speed matching during gear shifting; the speed information of each gear is stored in the form of a data table, which facilitates quick query and comparison and improves the operating efficiency of the system. S3. During vehicle operation, the transmission TCU waits and confirms that the AMT transmission has disengaged and returned to neutral; the specific steps of step S3 are as follows: S31. The transmission TCU responds to the downshift command and controls the shift actuator to switch the current gear to the neutral position; For example, during vehicle operation, the driver triggers a downshift command (from 4th gear to 3rd gear). After the TCU responds to the command, it controls the shift fork action of the shift actuator to switch the current 4th gear to the neutral position. S32. The transmission TCU confirms that the shift mechanism is in neutral by using the position sensor, and determines that the AMT transmission is in neutral disengagement state. For example, the TCU detects the position of the shift mechanism in real time through a position sensor. When the position signal fed back by the sensor is consistent with the preset neutral position threshold (±0.5mm), it determines that the AMT transmission has been disengaged and returned to neutral. It should be noted that the position sensor confirms that the shifting mechanism is in neutral, ensuring the accuracy and reliability of the shifting operation; and by responding to downshift commands and confirming the disengaged state in a timely manner, the delay in the shifting process is reduced. S4. In response to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position; the specific steps of step S4 are as follows: S41. Based on the engine's moment of inertia Clutch rotational inertia and the rotational inertia of the target gear of the transmission The percentage of the initial target position is calculated using the following formula. : Among them, the function Obtained by fitting experimental data; For example, the engine's moment of inertia is known. =0.8kg m 2 Clutch rotational inertia =0.1kg m 2 3rd gear of the transmission rotational inertia =0.3kg m 2 The initial target position percentage is calculated according to the formula; where the function is... The value was obtained based on fitting experimental data and took the following values. =0.6, and the initial target position percentage P0 is calculated to be 35%; S42. Query the clutch torque transmission characteristic curve to find the percentage relative to the initial target position. The corresponding clutch torque value; For example, querying the stored clutch torque characteristic curve, when P=35%, the corresponding clutch transmitted torque T=0.025×35 2 +3.2×35-120=285N m; S43. Based on the found clutch transmission torque value, drive the clutch to the initial target position by controlling the duty cycle of the clutch booster cylinder solenoid valve; For example, the TCU drives the clutch piston to move by controlling the duty cycle (40%) of the clutch booster cylinder solenoid valve, so that the clutch reaches the initial target position (corresponding to 35% of the total stroke, i.e., 7mm). It should be noted that the accuracy of the clutch engagement starting position is ensured by calculating the initial target position based on the rotational inertia of the engine and transmission; and the clutch is precisely controlled by querying the torque transmission characteristic curve and controlling the duty cycle of the solenoid valve. S5. The transmission TCU controls the clutch to engage more deeply from the initial target position according to a preset slope, thereby increasing the rotational speed of the input shaft and the engagement gear ring; the specific steps of step S5 are as follows: S51. Based on engine reference torque The gear ratio of the target gear and current throttle percentage The slope of the clutch engagement process can be calculated using the following formula. :
[0036] in, These are constants calibrated based on the system's moment of inertia; For example, the engine reference torque is known. =800N m, target gear (3rd gear) gear ratio i=3.2, current throttle percentage A=60%, system rotational inertia calibration constant. =0.005, according to the formula, the clutch engagement slope k = 0.005 × (800 × 3.2) / 60 = 0.213% / ms; S52. Starting from the initial target position, control the clutch to move according to the slope. The linear deepening of the interaction over time causes the input shaft speed to increase according to the following formula:
[0037] in, This represents the input shaft speed at time t. Indicates the initial input shaft speed; For example, starting from the initial target position (35%), the clutch is controlled to engage linearly with time according to the slope k, and the initial input shaft speed is... =3000 r / min, calculate the input shaft speed at t=100 ms using the formula. =3000 + 0.213 × 100 = 321.3 r / min, t = 300 ms =3000+0.213×300=363.9r / min; It should be noted that by calculating the clutch engagement slope based on engine torque, gear ratio, and throttle percentage, dynamic optimization of the clutch engagement process is achieved; by increasing the input shaft speed through a linear deepening engagement method, the accuracy and stability of speed synchronization are ensured. S6. The rotational speed of the engagement gear ring is detected by a speed sensor, and the detected speed is compared with the pre-stored rotational speed of the engagement sleeve of the target gear. When the rotational speed of the engagement gear ring reaches the shift window of the engagement sleeve of the target gear, a speed synchronization signal is generated. The specific steps of step S6 are as follows: S61. The rotational speed of the engaged gear ring is collected in real time via a speed sensor. ; For example, the rotational speed of the gear ring is collected in real time by a speed sensor at a frequency of 100Hz, and multiple sets of speed data are continuously acquired: 3050r / min, 3120r / min, 3380r / min, 4750r / min, and 4820r / min. S62. Retrieve the engagement gear speed of the target gear from the stored data table. ; For example, the engagement gear speed corresponding to gear 3 is retrieved from the data table stored in the TCU. =4800r / min; S63. Calculate the speed difference using the following formula. : ; The speed difference Synchronization tolerance with preset The synchronization tolerance was compared. Set according to the gear ratio; For example, the speed difference is calculated according to the formula. The preset synchronization tolerance for gear 3 is ±50 r / min; calculate the speed difference at each moment: At 3050 r / min, =1750r / min (greater than tolerance) At 4750 r / min, =50r / min (equal to tolerance) S64. When the speed difference Less than or equal to the synchronization tolerance When the shift window is reached, a speed synchronization signal is generated. For example, when a speed difference is detected When the speed reaches 50 r / min (less than or equal to the synchronization tolerance), the shift window is determined to be reached, and the TCU generates a speed synchronization signal. It should be noted that by collecting the rotational speed in real time and calculating the speed difference, the accurate judgment of speed synchronization is ensured; and by setting the synchronization tolerance according to the gear ratio, the adaptability and robustness of the system are improved. S7. In response to the generated speed synchronization signal, the transmission TCU activates the actuator solenoid valve, pushing the engagement sleeve to mesh with the engagement gear ring of the target gear, completing the gear shifting operation; the specific steps of step S7 are as follows: S71. The transmission TCU sends an activation command to the actuator solenoid valve; For example, the TCU sends an activation command (voltage 12V) to the actuator solenoid valve. S72. The actuator solenoid valve responds to the activation command and drives the engagement gear sleeve to move axially and engage with the engagement gear ring of the target gear position; For example, the actuator solenoid valve responds to the command and drives the engagement gear sleeve to move axially at a speed of 0.8 mm / ms, and completes engagement with the 3rd gear engagement ring; S73. After confirming successful gear engagement, control the clutch to fully engage and restore power transmission; For example, after the position sensor sends a signal that the gear has been successfully engaged, the TCU controls the clutch to continue to engage deeper until it is fully engaged (position percentage 100%), restoring the transmission of engine power to the transmission. The entire downshifting process is completed in 420ms. It should be noted that by activating the solenoid valve and confirming successful gear engagement, the efficiency and reliability of gear engagement are ensured; and by fully engaging the clutch immediately after confirming successful gear engagement, the power interruption time is reduced. This embodiment achieves dynamic downshifting from 4th to 3rd gear in commercial vehicle AMT through the above steps, reducing shift time by more than 30% compared to traditional methods. During the shifting process, the engine speed fluctuation is less than 8%, with no obvious jerking, effectively improving driving comfort and vehicle power.
[0038] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.
[0039] like Figure 2As shown, the following is an embodiment of the control system for dynamic downshifting of AMT in commercial vehicles provided in this disclosure. This system and the control methods for dynamic downshifting of AMT in commercial vehicles in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the control system for dynamic downshifting of AMT in commercial vehicles, please refer to the embodiments of the control methods for dynamic downshifting of AMT in commercial vehicles described above.
[0040] The system includes: The data storage module is used to pre-store the clutch torque transmission characteristic curves that characterize the engine torque values that the clutch can transmit at different engagement positions, as well as the engagement sleeve speeds of each gear. The status confirmation module is used to wait for and confirm that the AMT transmission has disengaged and returned to neutral while the vehicle is in motion; The clutch control module is used to respond to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position; further, it controls the clutch to deepen engagement from the initial target position according to a preset slope, so as to increase the speed of the input shaft and the engagement gear ring. The speed synchronization judgment module is used to detect the speed of the engagement gear ring through a speed sensor, and compare the detected speed with the speed of the engagement sleeve of the target gear in the pre-stored gear position. When the speed of the engagement gear ring reaches the shift window of the engagement sleeve speed of the target gear, a speed synchronization signal is generated. The gear shifting module is used to activate the solenoid valve of the actuator in response to the generated speed synchronization signal, which pushes the engagement sleeve to engage with the engagement gear ring of the target gear to complete the gear shifting operation.
[0041] This embodiment achieves efficient gear shifting control and improves the overall performance of the system through the interactive collaboration of the data storage module, status confirmation module, clutch control module, speed synchronization judgment module, and gear shifting execution module.
[0042] The storage medium provided in this application stores a program product that enables a control method for dynamic downshifting and gear shifting in an AMT (Automated Manual Transmission) for commercial vehicles.
[0043] The control method for dynamic downshifting in an AMT (Automated Manual Transmission) for commercial vehicles includes: the transmission TCU (Transmission Control Unit) pre-stores clutch torque characteristic curves representing the engine torque values that the clutch can transmit at different engagement positions; the transmission TCU pre-records and stores the engagement sleeve speeds for each gear; during vehicle operation, the transmission TCU waits for and confirms that the AMT transmission has disengaged and returned to neutral; in response to the confirmed disengaged and neutral state of the AMT transmission, and based on the pre-stored clutch torque characteristic curves, the transmission TCU controls the clutch to reach an initial target position; the transmission TCU controls the clutch to deepen engagement from the initial target position according to a preset slope to increase the speed of the input shaft and engagement gear ring; the speed of the engagement gear ring is detected by a speed sensor, and the detected speed is compared with the pre-stored engagement sleeve speed of the target gear; when the engagement sleeve speed reaches the shift window of the engagement sleeve speed of the target gear, a speed synchronization signal is generated; in response to the generated speed synchronization signal, the transmission TCU activates the actuator solenoid valve, pushing the engagement sleeve to mesh with the engagement sleeve of the target gear, completing the gear engagement operation.
[0044] In some possible implementations, the control method for dynamic downshifting and gear shifting in a commercial vehicle AMT of this disclosure can be implemented as a program product, which includes program code. When the program product is run on a terminal device, the program code is used to cause the terminal device to perform the steps described in the "Exemplary Methods" section above according to various exemplary embodiments of this disclosure.
[0045] The storage medium disclosed herein may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.
[0046] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A control method for dynamic downshifting in an AMT (Automated Manual Transmission) system for commercial vehicles, characterized in that, Includes the following steps: S1. The transmission TCU pre-stores clutch torque characteristic curves that represent the engine torque values that the clutch can transmit at different engagement positions; S2. The transmission TCU pre-records and stores the rotational speed of each gear engagement sleeve; S3. During vehicle operation, the transmission TCU waits and confirms that the AMT transmission has disengaged and returned to neutral. S4. In response to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position. S5. The transmission TCU controls the clutch to deepen engagement from the initial target position according to a preset slope, so as to increase the speed of the input shaft and the engagement gear ring; S6. The rotational speed of the gear ring is detected by the speed sensor, and the detected speed is compared with the rotational speed of the gear sleeve of the target gear in the pre-stored gear position. When the rotational speed of the gear ring reaches the shift window of the rotational speed of the gear sleeve of the target gear position, a speed synchronization signal is generated. S7. In response to the generated speed synchronization signal, the transmission TCU activates the actuator solenoid valve, pushing the engagement sleeve to engage with the engagement gear ring of the target gear, thus completing the gear shifting operation.
2. The control method for dynamic downshifting and gear shifting in a commercial vehicle AMT according to claim 1, characterized in that, The specific steps of step S1 are as follows: S11. Determine the original data of multiple clutch engagement positions and corresponding clutch transmission torque values through test bench calibration; S12. Quantify the clutch engagement position in the original data into a percentage relative to the total clutch travel; S13. Fit the quantified percentage form of the clutch engagement position to generate a continuous clutch torque transmission characteristic curve that represents the relationship between the percentage of the clutch position and the clutch transmitted torque value. S14. Store the clutch torque transmission characteristic curve in the non-volatile memory of the transmission TCU.
3. The control method for dynamic downshifting in a commercial vehicle AMT according to claim 1, characterized in that, The specific steps of step S2 are as follows: S21. Calculate the speed ratio of each gear based on the gear ratio of each gear in the transmission; S22. Taking each gear as the target gear, and based on the engine speed and the speed ratio of the target gear, calculate the target gear combined with the gear sleeve speed according to the following formula. : in, Engine speed, The gear ratio for the target gear; S23. Store each gear and its corresponding engagement gear speed in the transmission TCU in the form of a data table.
4. The control method for dynamic downshifting in a commercial vehicle AMT according to claim 3, characterized in that, The specific steps of step S3 are as follows: S31. The transmission TCU responds to the downshift command and controls the shift actuator to switch the current gear to the neutral position; S32. The transmission TCU confirms through the position sensor that the shifting mechanism is in neutral and determines that the AMT transmission is in neutral.
5. The control method for dynamic downshifting in a commercial vehicle AMT according to claim 4, characterized in that, The specific steps of step S4 are as follows: S41. Based on the engine's moment of inertia Clutch rotational inertia and the rotational inertia of the target gear of the transmission The percentage of the initial target position is calculated using the following formula. : Among them, the function Obtained by fitting experimental data; S42. Query the clutch torque transmission characteristic curve to find the percentage relative to the initial target position. The corresponding clutch torque value; S43. Based on the found clutch transmission torque value, drive the clutch to the initial target position by controlling the duty cycle of the clutch booster cylinder solenoid valve.
6. The control method for dynamic downshifting in a commercial vehicle AMT according to claim 1, characterized in that, The specific steps of step S5 are as follows: S51. Based on engine reference torque The gear ratio of the target gear and current throttle percentage The slope of the clutch engagement process can be calculated using the following formula. : in, These are constants calibrated based on the system's moment of inertia; S52. Starting from the initial target position, control the clutch to move according to the slope. The linear deepening of the interaction over time causes the input shaft speed to increase according to the following formula: in, This represents the input shaft speed at time t. This indicates the initial input shaft speed.
7. The control method for dynamic downshifting in a commercial vehicle AMT according to claim 6, characterized in that, The specific steps of step S6 are as follows: S61. The rotational speed of the engaged gear ring is collected in real time via a speed sensor. ; S62. Retrieve the engagement gear speed of the target gear from the stored data table. ; S63. Calculate the speed difference using the following formula. : ； The speed difference With preset synchronization tolerance The synchronization tolerance was compared. Set according to the gear ratio; S64. When the speed difference Less than or equal to the synchronization tolerance When the shift window is reached, a speed synchronization signal is generated.
8. The control method for dynamic downshifting in a commercial vehicle AMT according to claim 7, characterized in that, The specific steps of step S7 are as follows: S71. The transmission TCU sends an activation command to the actuator solenoid valve; S72. The actuator solenoid valve responds to the activation command and drives the engagement gear sleeve to move axially and engage with the engagement gear ring of the target gear position; S73. After confirming successful gear engagement, control the clutch to fully engage and restore power transmission.
9. A control system for dynamic downshifting in an AMT (Automated Manual Transmission) system for commercial vehicles, characterized in that, include: The data storage module is used to pre-store the clutch torque transmission characteristic curves that characterize the engine torque values that the clutch can transmit at different engagement positions, as well as the engagement sleeve speeds of each gear. The status confirmation module is used to wait for and confirm that the AMT transmission has disengaged and returned to neutral while the vehicle is in motion; The clutch control module is used to respond to the confirmed AMT transmission disengagement and return to neutral state, and based on the pre-stored clutch torque characteristic curve, the transmission TCU controls the clutch to reach the initial target position; further, it controls the clutch to deepen engagement from the initial target position according to a preset slope, so as to increase the speed of the input shaft and the engagement gear ring. The speed synchronization judgment module is used to detect the speed of the engagement gear ring through a speed sensor, and compare the detected speed with the speed of the engagement sleeve of the target gear in the pre-stored gear position. When the speed of the engagement gear ring reaches the shift window of the engagement sleeve speed of the target gear, a speed synchronization signal is generated. The gear shifting module is used to activate the solenoid valve of the actuator in response to the generated speed synchronization signal, which pushes the engagement sleeve to engage with the engagement gear ring of the target gear to complete the gear shifting operation.
10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method for dynamic downshifting and gear shifting of a commercial vehicle AMT as described in any one of claims 1 to 8.