Downshift control method, system and equipment for AMT (automated mechanical transmission)

Abstract

The invention discloses a downshift control method, system and equipment for an AMT transmission, and belongs to the technical field of automatic transmission control. According to the method, AMT braking and sliding working conditions are divided into four control stages by detecting the vehicle speed, the rotating speed of an engine and the state of a brake pedal, and when the vehicle speed is higher than a first preset vehicle speed, downshift is executed according to a vehicle speed threshold sequence; when the vehicle speed is lower than the first preset vehicle speed and higher than the second preset vehicle speed, whether downshift is conducted or not is determined according to the engine rotating speed and the brake pedal state; when the vehicle speed is lower than the second preset vehicle speed and higher than the third preset vehicle speed, the clutch is kept disengaged, and downshift is not executed; and when the vehicle speed is lower than the third preset vehicle speed, shifting to the starting gear and keeping the clutch disengaged. Through a staged control strategy, gear shifting rising and part abrasion under the low-speed braking working condition are effectively avoided, and gear shifting smoothness and system reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of automatic transmission control technology, and specifically to a downshift control method, system and device for an AMT transmission. Background Technology

[0002] During the operation of vehicles equipped with AMT (Automated Manual Transmission), the driver's operational characteristics during deceleration, coasting, and stopping are as follows: The driver depresses the brake pedal to reduce vehicle speed, and then frequently releases the brake pedal to allow the vehicle to coast and adjust speed based on the difference between the actual and expected speeds. This may involve repeated depressing and releasing of the brake pedal. Current AMT downshift control strategies generally employ a speed threshold trigger mode, meaning that a downshift is immediately executed when the vehicle speed drops to a preset fixed threshold.

[0003] The existing technology has the following core problems:

[0004] Poor overall vehicle smoothness: In the low gear range at lower vehicle speeds, the transmission speed of each gear in the AMT is relatively large. During gear shifting and after the clutch is engaged, the synchronization process between the engine and the AMT input shaft will generate a large interference torque. This torque is directly transmitted to the entire vehicle transmission system, causing the vehicle body to jerk noticeably. The driver and passengers can clearly perceive the jerking, resulting in a poor subjective driving experience.

[0005] AMT components suffer from severe wear: Due to the current strategy, downshifting is still frequently triggered at low speeds, causing the AMT shift actuators (such as shift forks and synchronizers) and clutch driven plates to bear repeated loads. The synchronizers need to frequently overcome the speed difference between the engine and the input shaft to achieve synchronization, and the friction wear between the synchronizer ring and the engagement sleeve accumulates during each synchronization process. The clutch driven plate needs to engage repeatedly after each shift, and the slippage process accelerates the wear of the driven plate friction plates.

[0006] Furthermore, the existing strategy does not consider the correlation between vehicle speed range and driving conditions, employing a one-size-fits-all speed threshold triggering method without differentiating control based on transmission characteristics and driver intentions at low speeds. At low speeds, the vehicle is significantly more sensitive to torque fluctuations than at high speeds, and the driver's primary need at this time is to smoothly decelerate to a stop. The existing strategy fails to meet this need, resulting in significant issues with smoothness and wear.

[0007] In summary, existing AMT downshift control methods suffer from poor smoothness and severe component wear under low-speed braking, coasting, and parking conditions. There is an urgent need for a differentiated downshift control method that combines operating condition classification and dynamic parameter adjustment to address the aforementioned technical deficiencies. Summary of the Invention

[0008] To address the aforementioned technical problems, the present invention aims to provide a downshift control method, system, and device for an AMT (Automated Manual Transmission) gearbox. Through a phased control strategy, it comprehensively considers factors such as vehicle speed, engine speed, brake pedal status, vehicle weight, and gradient to achieve intelligent downshift control. This solves problems such as poor shift smoothness and severe component wear in existing technologies.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a downshift control method for an AMT transmission, the method comprising:

[0011] Detect vehicle speed, engine speed, and brake pedal status;

[0012] Determine whether the engine speed is less than the first preset engine speed. When the vehicle speed is higher than the first preset vehicle speed, control the AMT to execute the first downshift control mode and perform downshift operation according to the vehicle speed threshold sequence.

[0013] When the vehicle speed is lower than the first preset speed but higher than the second preset speed, the AMT is controlled to execute the second downshift control mode; when the engine speed is lower than the first preset engine speed, the clutch is disengaged, and the decision to perform a downshift operation is made based on the brake pedal status.

[0014] When the vehicle speed is lower than the second preset speed but higher than the third preset speed, the AMT is controlled to execute the third downshift control mode; when the engine speed is lower than the first preset engine speed, the clutch is disengaged and kept disengaged, then downshifting is not performed.

[0015] When the vehicle speed is lower than the third preset speed, the AMT is controlled to execute the fourth downshift control mode, shifting to the starting gear and keeping the clutch disengaged.

[0016] Optionally, the detection of vehicle speed, engine speed, and brake pedal status includes: acquiring engine speed via the vehicle CAN bus, calculating vehicle mass via the vehicle controller, acquiring road slope via a slope sensor, and calculating the current vehicle speed via wheel speed signals acquired by wheel speed sensors.

[0017] Optionally, the control of the AMT to execute the first downshift control mode, and the downshift operation according to the vehicle speed threshold sequence includes: obtaining engine speed, vehicle mass, gradient and vehicle speed; when the brake pedal is detected to be depressed, obtaining the preset vehicle speed threshold sequence for downshifting each gear according to the vehicle mass and gradient; when the vehicle speed is less than any threshold in the vehicle speed threshold sequence, obtaining the target gear according to the vehicle mass, gradient and vehicle speed.

[0018] Control the AMT to perform a downshift operation to the target gear;

[0019] Once the gear shift is complete, the first preset speed is obtained by looking up the table based on the vehicle's mass and the gradient; when the vehicle speed is less than the first preset speed, the first downshift control mode is exited.

[0020] Optionally, after controlling the AMT to perform the downshift operation to the target gear, the method further includes: determining whether the AMT has shifted to the correct gear; if not, continuing to control the AMT to perform the downshift operation until the gear is shifted to the correct gear.

[0021] Optionally, the control of the AMT to execute the second downshift control mode includes: obtaining a first preset engine speed according to calibration; and disengaging the clutch when the engine speed is less than the first preset engine speed.

[0022] Once the clutch is fully disengaged, maintain the disengaged state.

[0023] The second preset speed is obtained by looking up the table based on the vehicle's mass and gradient. When the brake pedal is released, the target gear is obtained by looking up the table based on the vehicle's mass, gradient, and speed, and the gear shift is performed according to the target gear. When the brake pedal is not released, it is determined whether the vehicle speed is less than the second preset speed. If so, the second downshift control mode is exited.

[0024] Optionally, determining whether to downshift based on the brake pedal state includes: judging whether the driver has released the brake pedal based on the brake pedal state; if the brake pedal is released, downshifting is performed, otherwise downshifting is not performed.

[0025] Optionally, the control of the AMT to execute the third downshift control mode includes: obtaining a first preset engine speed according to calibration; disengaging the clutch when the engine speed is less than the first preset engine speed; maintaining clutch disengagement after the clutch is fully disengaged; obtaining a third preset vehicle speed by looking up a table based on vehicle mass and gradient; determining whether the vehicle speed is less than the third preset vehicle speed, and if so, exiting the third downshift control mode.

[0026] Optionally, the control of the AMT to execute the fourth downshift control mode includes: obtaining the starting gear from a table based on the vehicle weight and slope; performing a gear shift based on the starting gear; and maintaining clutch disengagement after the gear shift is complete.

[0027] Secondly, the present invention provides a downshift control system for an AMT transmission, the system comprising:

[0028] The detection module is used to detect vehicle speed, engine speed, and brake pedal status;

[0029] The first downshift control module is used to determine whether the engine speed is less than the first preset engine speed. When the vehicle speed is higher than the first preset vehicle speed, the AMT is controlled to execute the first downshift control mode and perform downshift operation according to the vehicle speed threshold sequence.

[0030] The second downshift control module is used to control the AMT to execute the second downshift control mode when the vehicle speed is lower than the first preset vehicle speed and higher than the second preset vehicle speed; when the engine speed is lower than the first preset engine speed, the clutch is disengaged, and the downshift operation is determined based on the brake pedal status.

[0031] The third downshift control module is used to control the AMT to execute the third downshift control mode when the vehicle speed is lower than the second preset vehicle speed and higher than the third preset vehicle speed; when the engine speed is lower than the first preset engine speed, the clutch is disengaged and the clutch is kept disengaged, then downshifting is not performed.

[0032] The fourth downshift control module is used to control the AMT to execute the fourth downshift control mode when the vehicle speed is lower than the third preset vehicle speed, to shift to the starting gear and keep the clutch disengaged.

[0033] Thirdly, the present invention provides an electronic device, the electronic device comprising:

[0034] At least one processor; and

[0035] A memory communicatively connected to the at least one processor; wherein,

[0036] The memory stores a computer program that can be executed by the at least one processor to enable the at least one processor to perform the method described in any one of the first aspects.

[0037] Compared with the closest prior art, the present invention has the following beneficial effects:

[0038] The present invention proposes a downshift control method, system and device for an AMT transmission. Through a phased control strategy, it avoids the jerking caused by shifting gears under low-speed braking conditions, significantly improves shift smoothness and enhances the driver's subjective experience.

[0039] The present invention reduces the wear of the shift actuator and clutch driven plate caused by frequent shifting during braking of the AMT, thereby improving the reliability and service life of the AMT.

[0040] This invention employs a dynamic lookup table method, adjusting the control threshold based on real-time parameters such as vehicle mass and slope, thereby improving control accuracy and adaptability. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0042] Figure 1 This is a flowchart of a downshift control method for an AMT transmission provided by the present invention;

[0043] Figure 2 This is a flowchart of the AMT downshift control method provided in Embodiment 1 of the present invention, which executes the first downshift control mode;

[0044] Figure 3 This is a flowchart of the second downshift control mode executed in the AMT downshift control method provided in Embodiment 1 of the present invention;

[0045] Figure 4 This is a flowchart of the third downshift control mode executed in the AMT downshift control method provided in Embodiment 1 of the present invention;

[0046] Figure 5 This is a flowchart of the AMT downshift control method provided in Embodiment 1 of the present invention, which executes the fourth downshift control mode;

[0047] Figure 6 This is a schematic diagram of the structural modules of the downshift control system for the AMT transmission provided by the present invention;

[0048] Figure 7 This is an internal structural diagram of the electronic device provided by the present invention. Detailed Implementation

[0049] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore merely examples, and should not be construed as limiting the scope of protection of the present invention.

[0050] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0051] This invention provides a downshift control method, system, and device for an AMT (Automated Manual Transmission). Embodiments of this invention are described below with reference to the accompanying drawings.

[0052] Please refer to Figure 1 This invention provides a downshift control method for an AMT transmission, which can be widely applied to various vehicle models and has strong versatility and practicality. Specifically, it includes the following steps:

[0053] S1 detects vehicle speed, engine speed, and brake pedal status;

[0054] S2 determines whether the engine speed is less than the first preset engine speed. When the vehicle speed is higher than the first preset vehicle speed, the AMT is controlled to execute the first downshift control mode and the downshift operation is performed according to the vehicle speed threshold sequence.

[0055] When the vehicle speed is lower than the first preset speed but higher than the second preset speed, the S3 controls the AMT to execute the second downshift control mode; when the engine speed is lower than the first preset engine speed, the clutch is disengaged, and the downshift operation is determined based on the brake pedal status.

[0056] When the vehicle speed is lower than the second preset speed but higher than the third preset speed, the S4 controls the AMT to execute the third downshift control mode; when the engine speed is lower than the first preset engine speed, the clutch is disengaged and kept disengaged, then downshifting is not performed.

[0057] When the vehicle speed is lower than the third preset speed, the S5 controls the AMT to execute the fourth downshift control mode, shifting to the starting gear and keeping the clutch disengaged.

[0058] In step S1 above, detecting vehicle speed, engine speed, and brake pedal status includes: acquiring engine speed via the vehicle CAN bus, calculating vehicle mass via the vehicle controller, acquiring road slope via a slope sensor, and calculating the current vehicle speed via wheel speed signals acquired by wheel speed sensors.

[0059] In step S2 above, controlling the AMT to execute the first downshift control mode and performing downshifting operation according to the vehicle speed threshold sequence includes: obtaining engine speed, vehicle mass, gradient, and vehicle speed; when the brake pedal is detected to be depressed, obtaining the preset vehicle speed threshold sequence for downshifting each gear according to the vehicle mass and gradient; when the vehicle speed is less than any threshold in the vehicle speed threshold sequence, obtaining the target gear according to the vehicle mass, gradient, and vehicle speed.

[0060] Control the AMT to perform a downshift operation to the target gear;

[0061] Once the gear shift is complete, the first preset speed is obtained by looking up the table based on the vehicle's mass and the gradient; when the vehicle speed is less than the first preset speed, the first downshift control mode is exited.

[0062] In the above embodiments, obtaining the preset speed threshold sequence for downshifting at each gear by looking up a table based on vehicle mass and slope includes: dynamically adjusting the speed threshold based on pre-stored table lookup data and the real-time acquired vehicle mass and slope.

[0063] In the above embodiments, after controlling the AMT to perform the downshift operation to the target gear, the method further includes: determining whether the AMT has shifted to the correct gear; if not, continuing to control the AMT to perform the downshift operation until the gear is shifted to the correct gear.

[0064] In step S3 above, controlling the AMT to execute the second downshift control mode includes: obtaining a first preset engine speed according to calibration; when the engine speed is less than the first preset engine speed, disengaging the clutch;

[0065] Once the clutch is fully disengaged, maintain the disengaged state.

[0066] The second preset speed is obtained by looking up the table based on the vehicle's mass and gradient. When the brake pedal is released, the target gear is obtained by looking up the table based on the vehicle's mass, gradient, and speed, and the gear shift is performed according to the target gear. When the brake pedal is not released, it is determined whether the vehicle speed is less than the second preset speed. If so, the second downshift control mode is exited.

[0067] In the above embodiments, obtaining the target gear by looking up a table based on vehicle mass, slope, and speed includes: determining the matching target gear based on pre-stored lookup table data and real-time acquired vehicle mass, slope, and speed.

[0068] In step S3 above, determining whether to downshift based on the brake pedal state includes: judging whether the driver has released the brake pedal based on the brake pedal state; if the brake pedal is released, downshifting is performed, otherwise downshifting is not performed.

[0069] In step S4 above, controlling the AMT to execute the third downshift control mode includes: obtaining the first preset engine speed according to calibration; when the engine speed is less than the first preset engine speed, disengaging the clutch; after the clutch is fully disengaged, maintaining the clutch disengagement; obtaining the third preset vehicle speed by looking up a table based on the vehicle mass and slope; determining whether the vehicle speed is less than the third preset vehicle speed, and if so, exiting the third downshift control mode.

[0070] In step S5 above, controlling the AMT to execute the fourth downshift control mode includes: looking up the starting gear in a table based on the vehicle weight and slope; performing a gear shift based on the starting gear; and maintaining clutch disengagement after the gear shift is complete.

[0071] In the above embodiments, obtaining the starting gear by looking up a table based on vehicle mass and slope includes: determining the starting gear based on pre-stored lookup table data and the real-time acquired vehicle mass and slope.

[0072] Example 1: In one embodiment, to make the technical solution of the present invention clearer and easier to understand, the following describes a specific implementation method for AMT downshift control. This method divides the AMT braking and coasting conditions into four stages and executes corresponding control strategies according to different vehicle speeds, engine speeds, and brake pedal states. The downshift control method for the AMT transmission (mechanical automatic transmission) of the present invention is described in detail to achieve smooth downshifting and reduce component wear. The specific implementation process is as follows:

[0073] Phase 1: First downshift control mode (at higher vehicle speeds)

[0074] like Figure 2 As shown, when the vehicle speed exceeds the first preset speed, the first downshift control mode is executed. The specific steps are as follows:

[0075] Step 101: Acquire engine speed, vehicle mass, gradient, and vehicle speed. These parameters are collected in real time by vehicle sensors, such as engine speed sensors, mass sensors (e.g., load sensors), gradient sensors (e.g., tilt sensors), and vehicle speed sensors.

[0076] Step 102: Determine if the driver has pressed the brake pedal. If yes, proceed to step 103; otherwise, return to step 101 and continue monitoring.

[0077] Step 103: Based on the vehicle mass and gradient, look up the table to obtain the preset downshift speed threshold sequence for each gear. This lookup process is based on a pre-stored data mapping table and dynamically adjusts the downshift speed threshold for each gear according to the real-time vehicle mass and gradient to ensure that the thresholds adapt to actual driving conditions.

[0078] Step 104: Determine if the vehicle speed is less than the speed threshold in the sequence. If yes, proceed to step 105; otherwise, return to step 103 and re-obtain the threshold sequence.

[0079] Step 105: Determine the target gear by looking up the table based on the vehicle's mass, gradient, and speed. Also based on pre-stored table data, determine the appropriate target gear according to real-time parameters.

[0080] Step 106: The AMT performs a gear shift according to the target gear. Gear switching is achieved by controlling the gear shift actuator.

[0081] Step 107: Determine if the AMT gear shift is complete. If yes, proceed to step 108; otherwise, return to step 106 and continue shifting.

[0082] Step 108: Based on the vehicle mass and gradient, look up the table to obtain the first preset speed. This first preset speed is used to determine whether to exit the first downshift control mode.

[0083] Step 109: Determine if the vehicle speed is less than the first preset speed. If yes, the first stage is completed and the second stage (second downshift control mode) is entered; if no, return to step 103 and continue executing the first downshift control mode.

[0084] Second stage: Second downshift control mode (when vehicle speed decreases)

[0085] like Figure 3 As shown, when the vehicle speed is lower than the first preset speed but higher than the second preset speed, the second downshift control mode is executed. The specific steps are as follows:

[0086] Step 201: Obtain the first preset engine speed based on calibration. This value is determined by the engine control unit calibration and typically corresponds to the engine idle speed.

[0087] Step 202: Determine if the engine speed is less than the first preset engine speed. If yes, proceed to step 203; otherwise, return to step 201 and continue monitoring.

[0088] Step 203: Clutch disengagement. Disengagement is achieved by controlling the clutch actuator.

[0089] Step 204: Determine if the clutch is fully disengaged. If yes, proceed to step 205; otherwise, return to step 203 and continue disengaging.

[0090] Step 205: AMT keeps the clutch disengaged.

[0091] Step 206: Based on the vehicle mass and gradient, look up the table to obtain the second preset speed. This second preset speed is used to determine whether to exit the second downshift control mode.

[0092] Step 207: Determine whether the driver has released the brake pedal. If yes, proceed to step 209; otherwise, proceed to step 208.

[0093] Step 208: Determine if the vehicle speed is less than the second preset speed. If yes, the second stage is completed and the third stage (third downshift control mode) is entered; if no, return to step 205 and continue to keep the clutch disengaged.

[0094] Step 209: Based on the vehicle's mass, gradient, and speed, consult the table to obtain the target gear.

[0095] Step 210: The AMT performs a gear shift according to the target gear.

[0096] Step 211: Determine if the AMT gear shift is complete. If yes, proceed to step 212; otherwise, return to step 210 and continue shifting.

[0097] Step 212: Determine if the vehicle speed is less than the second preset speed. If yes, the second stage is completed and the third stage begins; otherwise, return to step 201 and re-execute the second downshift control mode.

[0098] Third stage: Third downshift control mode (when vehicle speed decreases further)

[0099] like Figure 4 As shown, when the vehicle speed is lower than the second preset speed but higher than the third preset speed, the third downshift control mode is executed. The specific steps are as follows:

[0100] Step 301: Obtain the first preset engine speed according to the calibration.

[0101] Step 302: Determine if the engine speed is less than the first preset engine speed. If yes, return to step 301; otherwise, proceed to step 303. This step ensures that subsequent operations are only performed when the engine speed is below the threshold.

[0102] Step 303: The clutch is disengaged.

[0103] Step 304: Determine if the clutch is fully disengaged. If yes, return to step 303; otherwise, proceed to step 305.

[0104] Step 305: AMT keeps the clutch disengaged.

[0105] Step 306: Based on the vehicle mass and gradient, look up the table to obtain the third preset speed. This third preset speed is used to determine whether to exit the third downshift control mode.

[0106] Step 307: Determine if the vehicle speed is less than the third preset speed. If yes, the third stage is completed and the process enters the fourth stage (fourth downshift control mode); if no, return to step 305 and continue to keep the clutch disengaged.

[0107] Phase 4: Fourth downshift control mode (at extremely low vehicle speeds)

[0108] like Figure 5 As shown, when the vehicle speed is lower than the third preset speed, the fourth downshift control mode is activated. The specific steps are as follows:

[0109] Step 401: Determine the starting gear by referring to a table based on the vehicle's mass and the gradient. The starting gear is usually 1st or 2nd gear, depending on the vehicle's design.

[0110] Step 402: The AMT performs a gear shift based on the starting gear.

[0111] Step 403: Determine if the AMT gear shift is complete. If yes, proceed to step 404; otherwise, return to step 402 and continue shifting.

[0112] Step 404: Keep the clutch disengaged until the vehicle accelerates again or the driver operates the clutch.

[0113] Through the control of the above four stages, the AMT achieves intelligent downshifting under braking and coasting conditions, effectively avoiding low-speed shift jerking and component wear.

[0114] Based on the same inventive concept, this application also provides a downshift control system for an AMT transmission to implement the above-described downshift control method. The solution provided by this system is similar to the implementation described in the above-described embodiments. Therefore, the specific limitations of one or more AMT transmission downshift control system embodiments provided below can be found in the limitations of the AMT transmission downshift control method described above, and will not be repeated here.

[0115] In one embodiment, the downshift control system of an AMT transmission provided by this invention, such as... Figure 6 As shown, it includes: a detection module 110, a first downshift control module 120, a second downshift control module 130, a third downshift control module 140, and a fourth downshift control module 150, wherein:

[0116] Detection module 110 is used to detect vehicle speed, engine speed and brake pedal status;

[0117] The first downshift control module 120 is used to determine whether the engine speed is less than the first preset engine speed. When the vehicle speed is higher than the first preset vehicle speed, it controls the AMT to execute the first downshift control mode and performs downshift operation according to the vehicle speed threshold sequence.

[0118] The second downshift control module 130 is used to control the AMT to execute the second downshift control mode when the vehicle speed is lower than the first preset vehicle speed and higher than the second preset vehicle speed; and to disengage the clutch when the engine speed is lower than the first preset engine speed, and to determine whether to perform a downshift operation based on the brake pedal status.

[0119] The third downshift control module 140 is used to control the AMT to execute the third downshift control mode when the vehicle speed is lower than the second preset vehicle speed and higher than the third preset vehicle speed; when the engine speed is lower than the first preset engine speed, the clutch is disengaged and the clutch is kept disengaged, then downshifting is not performed.

[0120] The fourth downshift control module 150 is used to control the AMT to execute the fourth downshift control mode when the vehicle speed is lower than the third preset vehicle speed, to shift to the starting gear and keep the clutch disengaged.

[0121] In one embodiment, an electronic device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown. The electronic device includes a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements the downshift control method for an AMT transmission as described in any one of steps S101 to S105. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the device's casing, or an external keyboard, touchpad, or mouse.

[0122] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0123] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0124] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0125] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0127] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A downshift control method for an AMT transmission, characterized in that, The method includes: Detect vehicle speed, engine speed, and brake pedal status; Determine whether the engine speed is less than the first preset engine speed. When the vehicle speed is higher than the first preset vehicle speed, control the AMT to execute the first downshift control mode and perform downshift operation according to the vehicle speed threshold sequence. When the vehicle speed is lower than the first preset speed but higher than the second preset speed, the AMT is controlled to execute the second downshift control mode; when the engine speed is lower than the first preset engine speed, the clutch is disengaged, and the decision to perform a downshift operation is made based on the brake pedal status. When the vehicle speed is lower than the second preset speed but higher than the third preset speed, the AMT is controlled to execute the third downshift control mode; when the engine speed is lower than the first preset engine speed, the clutch is disengaged and kept disengaged, then downshifting is not performed. When the vehicle speed is lower than the third preset speed, the AMT is controlled to execute the fourth downshift control mode, shifting to the starting gear and keeping the clutch disengaged.

2. The method according to claim 1, characterized in that, The detection of vehicle speed, engine speed, and brake pedal status includes: acquiring engine speed via the vehicle CAN bus, calculating vehicle mass via the vehicle controller, acquiring road slope via a slope sensor, and calculating the current vehicle speed via wheel speed signals acquired by wheel speed sensors.

3. The method according to claim 1, characterized in that, The AMT is controlled to execute the first downshift control mode. The downshift operation based on the vehicle speed threshold sequence includes: acquiring engine speed, vehicle mass, gradient, and vehicle speed; when the brake pedal is detected to be depressed, obtaining the preset vehicle speed threshold sequence for downshifting each gear based on the vehicle mass and gradient; when the vehicle speed is less than any threshold in the vehicle speed threshold sequence, obtaining the target gear based on the vehicle mass, gradient, and vehicle speed. Control the AMT to perform a downshift operation to the target gear; Once the gear shift is complete, the first preset speed is obtained by looking up the table based on the vehicle's mass and the gradient; when the vehicle speed is less than the first preset speed, the first downshift control mode is exited.

4. The method according to claim 3, characterized in that, After controlling the AMT to perform the downshift operation to the target gear, the method further includes: determining whether the AMT has shifted to the correct gear; if not, continuing to control the AMT to perform the downshift operation until the gear is shifted to the correct gear.

5. The method according to claim 1, characterized in that, The control of the AMT to execute the second downshift control mode includes: obtaining a first preset engine speed according to calibration; and disengaging the clutch when the engine speed is less than the first preset engine speed. Once the clutch is fully disengaged, maintain the disengaged state. The second preset speed is obtained by looking up the table based on the vehicle's mass and gradient. When the brake pedal is released, the target gear is obtained by looking up the table based on the vehicle's mass, gradient, and speed, and the gear shift is performed according to the target gear. When the brake pedal is not released, it is determined whether the vehicle speed is less than the second preset speed. If so, the second downshift control mode is exited.

6. The method according to claim 1, characterized in that, The step of determining whether to downshift based on the brake pedal state includes: judging whether the driver has released the brake pedal based on the brake pedal state; if the brake pedal is released, downshifting is performed, otherwise downshifting is not performed.

7. The method according to claim 1, characterized in that, The control of the AMT to execute the third downshift control mode includes: obtaining a first preset engine speed according to calibration; When the engine speed is lower than the first preset engine speed, the clutch is disengaged; once the clutch is fully disengaged, the clutch remains disengaged. The third preset speed is obtained by looking up the table based on the vehicle mass and slope; it is then determined whether the vehicle speed is less than the third preset speed. If so, the third downshift control mode is exited.

8. The method according to claim 1, characterized in that, The control mode for AMT to execute the fourth downshift control mode includes: obtaining the starting gear by looking up a table based on the vehicle weight and slope; performing a gear shift based on the starting gear; and maintaining clutch disengagement after the gear shift is complete.

9. A downshift control system for an AMT transmission, characterized in that, The system includes: The detection module is used to detect vehicle speed, engine speed, and brake pedal status; The first downshift control module is used to determine whether the engine speed is less than the first preset engine speed. When the vehicle speed is higher than the first preset vehicle speed, the AMT is controlled to execute the first downshift control mode and perform downshift operation according to the vehicle speed threshold sequence. The second downshift control module is used to control the AMT to execute the second downshift control mode when the vehicle speed is lower than the first preset vehicle speed and higher than the second preset vehicle speed; when the engine speed is lower than the first preset engine speed, the clutch is disengaged, and the downshift operation is determined based on the brake pedal status. The third downshift control module is used to control the AMT to execute the third downshift control mode when the vehicle speed is lower than the second preset vehicle speed and higher than the third preset vehicle speed; when the engine speed is lower than the first preset engine speed, the clutch is disengaged and the clutch is kept disengaged, then downshifting is not performed. The fourth downshift control module is used to control the AMT to execute the fourth downshift control mode when the vehicle speed is lower than the third preset vehicle speed, to shift to the starting gear and keep the clutch disengaged.

10. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-8.

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