A control method for hill frequent shifting of an AMT automatic transmission of a commercial vehicle

Abstract

This invention provides a method for controlling frequent gear shifting on inclines in commercial vehicles using an AMT (Automated Manual Transmission). The method includes: acquiring the vehicle's driving state and determining whether to trigger the frequent gear shifting control function based on the driving state, wherein the driving state includes: road surface condition, driving mode, vehicle gear, shift request, and driving acceleration; if so, determining whether the triggering condition is met; if so, performing an upshift arbitration logic judgment; when the upshift arbitration condition is met, setting the upshift prohibition flag to ON, prohibiting upshifting; when the upshift arbitration condition is not met, setting the upshift prohibition flag to OFF, allowing upshifting; when the upshift prohibition flag is ON, maintaining the current vehicle's driving position to fully utilize the power of the current gear. This invention avoids frequent upshifts and downshifts, ensuring the vehicle's power and safety during incline.

Description

Technical Field

[0001] This invention relates to the technical field of AMT automatic transmission shift control, and more particularly to a control method for frequent shifting of AMT automatic transmissions in commercial vehicles on slopes. Background Technology

[0002] Currently, automatic transmission commercial vehicles are gradually gaining market attention and popularity because they are mainly used for long-distance transportation and urban hauling, and automatic transmissions can alleviate driver fatigue and improve the driving experience. However, existing commercial vehicles are prone to cyclical shifting of gears (2-3-2, 3-4-3) when climbing hills. There are two main reasons for this. Firstly, commercial vehicles often have heavy loads, and the AMT (Automated Manual Transmission) experiences brief power interruptions during gear shifts. If shifting occurs during a climb, such as requesting a shift from 2nd to 3rd gear after the vehicle has gained speed, the speed may drop significantly during the power interruption. When shifting to 3rd gear, the speed triggers a downshift to 2nd gear, resulting in another downshift from 3rd to 2nd, leading to a 2-3-2 cyclic shifting pattern and prolonged power interruptions. Secondly, if the driver experiences sudden changes in the accelerator pedal during a climb (rapid release and rapid acceleration), it can also cause changes in the shift lines, resulting in cyclical shifting. This cyclical shifting not only affects the driving experience, resulting in poor power delivery and difficulty climbing hills, but also has a certain impact on the lifespan of the hardware. Therefore, controlling the shifting of the AMT automatic transmission to avoid frequent upshifts and downshifts is of great significance. Summary of the Invention

[0003] This invention provides a control method for frequent gear shifting of AMT automatic transmissions in commercial vehicles on slopes, which solves the problem that frequent gear shifting during short periods of time in existing commercial vehicles can cause power interruption and, in severe cases, prevent smooth climbing. It can avoid frequent upshifting and downshifting, and ensure the power and safety of the vehicle during the climbing process.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for controlling frequent gear shifting on inclines in a commercial vehicle AMT automatic transmission includes:

[0006] The vehicle's driving status is obtained, and the frequent gear shift control function is triggered based on the driving status. The driving status includes: road surface condition, driving mode, vehicle gear, gear shift request, and driving acceleration.

[0007] If so, determine whether the triggering condition is met; if it is, proceed with the upshift arbitration logic.

[0008] When the conditions for upshift arbitration are met, the upshift prohibition flag will be turned ON, prohibiting upshifting; when the conditions for upshift arbitration are not met, the upshift prohibition flag will be turned OFF, allowing upshifting.

[0009] When the "No Upshift" sign is ON, keep the vehicle moving to allow the current gear to provide full power.

[0010] Preferred options also include:

[0011] The conditions for forcibly exiting the frequent gear shifting control function are set. When the vehicle status meets the conditions for forced exit, the upshift arbitration logic restriction is exited.

[0012] Preferably, determining whether the triggering condition is met includes:

[0013] 1) The TCU sends an upgrade request;

[0014] 2) The TCU upshift request is within the allowed gear range;

[0015] 3) The vehicle's slope detection status is not downhill;

[0016] 4) The driving mode is not in cruise control mode;

[0017] 5) The driving mode is not in ECO mode;

[0018] 6) The vehicle's current actual acceleration is less than the calibrated acceleration threshold;

[0019] When all conditions 1) to 6) are met, the frequent gear shifting control function is activated.

[0020] Preferably, the step of performing the upshift arbitration logic judgment includes:

[0021] Obtain the actual acceleration a1, actual torque T1, maximum vehicle speed Vimax in the current gear, total gear ratio i1 in the current gear, and total gear ratio i2 in the target gear at the moment the vehicle shift request is issued;

[0022] According to the formula: The target acceleration is calculated, where η is the set efficiency and m is the vehicle load.

[0023] Preferably, the step of performing the upshift arbitration logic judgment further includes:

[0024] The target acceleration corresponding to the target gear is calculated, and combined with the vehicle speed in the current gear, it is comprehensively judged whether the power performance of the current gear is fully utilized. If the power performance is not fully utilized, an upshift prohibition sign is output; otherwise, the upshift prohibition sign is set to OFF.

[0025] Preferably, the upshift arbitration conditions include:

[0026] Condition 1: The target acceleration is less than or equal to the acceleration threshold achievable under the current slope and gear; or

[0027] Condition 2: When the current actual vehicle speed is less than or equal to the maximum vehicle speed Vimax of the current gear, the following conditions are met:

[0028] The torque value obtained from the engine universal characteristic table corresponding to the current throttle opening is less than the torque value obtained from the engine universal characteristic table corresponding to the target throttle opening, or the output torque of the transmission in the current gear is greater than or equal to the output torque of the transmission in the target gear.

[0029] Preferably, the forced exit condition includes:

[0030] 1) During function execution, the TCU requests to shift up and return to the current driving gear;

[0031] 2) Switch the driving mode to ECO or cruise control.

[0032] 3) The engine speed exceeds the maximum speed specified for the current gear;

[0033] 4) The current actual acceleration of the vehicle is greater than the acceleration threshold for exiting;

[0034] When any of the conditions 1) to 4) are met, the frequent shift function trigger flag is set to OFF, and the transmission controller returns to normal control logic.

[0035] This invention provides a control method for frequent gear shifting of AMT automatic transmissions in commercial vehicles on slopes. The method determines whether to trigger the frequent gear shifting control function based on the vehicle status. If the triggering condition is met, the method enters the upshift arbitration strategy logic to determine whether upshifting is allowed. This solves the problem of short-term frequent gear shifting in existing commercial vehicles during uphill climbing, which can lead to power interruption and, in severe cases, prevent smooth climbing. It avoids frequent upshifting and downshifting, ensuring the power and safety of the vehicle during uphill climbing. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0037] Figure 1 This is a schematic diagram of a control method for frequent gear shifting on slopes in a commercial vehicle AMT automatic transmission provided by the present invention.

[0038] Figure 2 This is a flowchart illustrating the frequent gear shifting control function provided in an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and implementation methods.

[0040] To address the problem of power interruption caused by frequent gear shifting when commercial vehicles are climbing hills, this invention provides a control method for frequent gear shifting of AMT automatic transmissions in commercial vehicles on slopes. This method solves the problem of power interruption caused by short-term frequent gear shifting during the climbing process of existing commercial vehicles, which can even prevent them from climbing smoothly in severe cases. It can avoid frequent upshifting and downshifting, ensuring the power and safety of the vehicle during the climbing process.

[0041] like Figure 1 A method for controlling frequent gear shifting on inclines in a commercial vehicle AMT automatic transmission, comprising:

[0042] S1: Obtain the vehicle's driving status and determine whether to trigger the activation of the frequent gear shift control function based on the driving status. The driving status includes: road surface condition, driving mode, vehicle driving gear, gear shift request, and driving acceleration.

[0043] S2: If so, determine whether the triggering condition is met. If it is met, perform the upshift arbitration logic judgment.

[0044] S3: When the upshift arbitration conditions are met, the upshift prohibition flag will be set to ON, prohibiting upshifting; when the upshift arbitration conditions are not met, the upshift prohibition flag will be set to OFF, allowing upshifting.

[0045] S4: When the "No Upshift" sign is ON, keep the vehicle moving to allow the current gear to provide full power.

[0046] Specifically, such as Figure 2As shown, the transmission control unit (TCU) first determines whether to trigger the frequent shift control function based on factors such as vehicle driving status, road conditions (uphill / downhill / flat road), driving mode, vehicle gear, shift request, and acceleration. If the function triggering conditions are met, the upshift arbitration strategy logic is entered, setting the upshift prohibition flag to ON; otherwise, the upshift prohibition flag is set to OFF. If the function triggering conditions are not met, the upshift prohibition flag is set to OFF. The upshift arbitration strategy logic calculates the target gear's predicted acceleration, the target gear's torque transmission status, and combines this with factors such as the current gear's driving speed to comprehensively determine whether the current gear's power performance is fully utilized. If the power performance is not fully utilized, the upshift prohibition flag is output (ON); otherwise, the upshift prohibition flag is set to OFF, allowing upshifting. This method effectively reduces or even solves the problem of frequent shifting (cyclic shifting) during commercial vehicle hill climbing, improving driving dynamics, comfort, and safety. The above is the arbitration process of the frequent gear shifting control function. When the upshift prohibition sign is ON, it means that the vehicle needs to continue driving until the current gear's power is fully utilized. This can avoid the problem of frequent gear shifting caused by unreasonable upshift requests, which result in upshifting and then immediately downshifting.

[0047] Furthermore, determining whether the triggering condition is met includes:

[0048] 1) The TCU sends an upgrade request;

[0049] 2) The TCU upshift request is within the allowed gear range;

[0050] 3) The vehicle's slope detection status is not downhill;

[0051] 4) The driving mode is not in cruise control mode;

[0052] 5) The driving mode is not in ECO mode;

[0053] 6) The vehicle's current actual acceleration is less than the calibrated acceleration threshold;

[0054] When conditions 1) through 6) are all met, the frequent gear shift control function is activated. The limit values ​​for each of the above conditions were obtained based on statistical analysis of experimental data.

[0055] Furthermore, the step of performing the upshift arbitration logic judgment includes:

[0056] Obtain the actual acceleration a1, actual torque T1, maximum vehicle speed Vimax in the current gear, total gear ratio i1 in the current gear, and total gear ratio i2 in the target gear at the moment the vehicle shift request is issued;

[0057] According to the formula: The target acceleration is calculated, where η is the set efficiency and m is the vehicle load.

[0058] In practical applications, the maximum speed in the current gear Vimax = the maximum speed under overload on flat roads + the compensation value for slope conditions. The maximum speed under overload on flat roads and the compensation value for slope conditions can be obtained through experiments.

[0059] Furthermore, the step of performing the upshift arbitration logic judgment also includes:

[0060] The target acceleration corresponding to the target gear is calculated, and combined with the vehicle speed in the current gear, it is comprehensively judged whether the power performance of the current gear is fully utilized. If the power performance is not fully utilized, an upshift prohibition sign is output; otherwise, the upshift prohibition sign is set to OFF.

[0061] Furthermore, the aforementioned arbitration conditions include:

[0062] Condition 1: The target acceleration is less than or equal to the acceleration threshold achievable under the current slope and gear; or

[0063] Condition 2: When the current actual vehicle speed is less than or equal to the maximum vehicle speed Vimax of the current gear, the following conditions are met:

[0064] The torque value obtained from the engine universal characteristic table corresponding to the current throttle opening is less than the torque value obtained from the engine universal characteristic table corresponding to the target throttle opening, or the output torque of the transmission in the current gear is greater than or equal to the output torque of the transmission in the target gear.

[0065] The method also includes setting conditions for forcibly exiting the frequent gear shifting control function. When the vehicle status meets the conditions for forced exit, the upshift arbitration logic restriction is exited.

[0066] Furthermore, the forced exit conditions include:

[0067] 1) During function execution, the TCU requests to shift up and return to the current driving gear;

[0068] 2) Switch the driving mode to ECO or cruise control.

[0069] 3) The engine speed exceeds the maximum speed specified for the current gear;

[0070] 4) The current actual acceleration of the vehicle is greater than the acceleration threshold for exiting;

[0071] When any of the conditions 1) to 4) are met, the frequent shift function trigger flag is set to OFF, and the transmission controller returns to normal control logic.

[0072] As can be seen, the present invention provides a control method for frequent gear shifting of AMT automatic transmission in commercial vehicles on slopes. The method determines whether to trigger the frequent gear shifting control function based on the vehicle status. If the triggering condition is met, the method enters the upshift arbitration strategy logic to determine whether upshifting is allowed. This solves the problem that existing commercial vehicles experience short-term frequent gear shifting during uphill climbing, which can lead to power interruption and, in severe cases, prevent smooth uphill climbing. It avoids frequent upshifting and downshifting, ensuring the power and safety of the vehicle during uphill climbing.

[0073] The structure, features, and effects of the present invention have been described in detail above with reference to the embodiments shown in the figures. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification and figures.

Claims

1. A control method for frequent gear shifting on inclines in a commercial vehicle AMT automatic transmission, characterized in that, include: The vehicle's driving status is obtained, and the frequent gear shift control function is triggered based on the driving status. The driving status includes: road surface condition, driving mode, vehicle gear, gear shift request, and driving acceleration. If so, determine whether the triggering condition is met; if it is, proceed with the upshift arbitration logic. When the conditions for upshift arbitration are met, the upshift prohibition flag will be turned ON, prohibiting upshifting; when the conditions for upshift arbitration are not met, the upshift prohibition flag will be turned OFF, allowing upshifting. When the "No Upshift" sign is ON, keep the vehicle moving to allow the current gear to provide full power. The upshift arbitration strategy logic calculates the target acceleration and torque transmission status of the target gear, and combines this with the vehicle speed in the current gear to comprehensively judge whether the power performance of the current gear is fully utilized. If the power performance is not fully utilized, the upshift prohibition sign is turned ON; otherwise, the upshift prohibition sign is turned OFF.

2. The control method for frequent gear shifting on slopes in a commercial vehicle AMT automatic transmission according to claim 1, characterized in that, Also includes: The conditions for forcibly exiting the frequent gear shifting control function are set. When the vehicle status meets the conditions for forced exit, the upshift arbitration logic restriction is exited.

3. The control method for frequent gear shifting on slopes in a commercial vehicle AMT automatic transmission according to claim 2, characterized in that, The determination of whether the triggering condition is met includes: 1) The TCU issues an upgrade request; 2) The TCU upshift request is within the allowed gear range; 3) The vehicle's slope detection status is not downhill; 4) The driving mode is not in cruise control mode; 5) The driving mode is not set to ECO mode; 6) The vehicle's current actual acceleration is less than the calibrated acceleration threshold; When all conditions 1) to 6) are met, the frequent gear shifting control function is activated.

4. The control method for frequent gear shifting on slopes in a commercial vehicle AMT automatic transmission according to claim 3, characterized in that, The upshift arbitration logic judgment includes: Obtain the actual acceleration a1, actual torque T1, maximum vehicle speed Vimax in the current gear, total gear ratio i1 in the current gear, and total gear ratio i2 in the target gear at the moment the vehicle shift request is issued; According to the formula: The target acceleration is calculated, where η is the set efficiency and m is the vehicle load.

5. The control method for frequent gear shifting on slopes in a commercial vehicle AMT automatic transmission according to claim 4, characterized in that, The conditions for upgrading arbitration include: Condition 1: The target acceleration is less than or equal to the acceleration threshold achievable under the current slope and gear; or Condition 2: When the current actual vehicle speed is less than or equal to the maximum speed Vimax of the current gear, the following conditions are met: The torque value obtained from the engine universal characteristic table corresponding to the current throttle opening is less than the torque value obtained from the engine universal characteristic table corresponding to the target throttle opening, or the output torque of the transmission in the current gear is greater than or equal to the output torque of the transmission in the target gear.

6. The control method for frequent gear shifting on slopes in a commercial vehicle AMT automatic transmission according to claim 5, characterized in that, The forced exit conditions include: 1) During function execution, the TCU requests to shift up and return to the current driving gear; 2) Switch the driving mode to ECO or cruise control. 3) The engine speed exceeds the maximum speed specified for the current gear; 4) The current actual acceleration of the vehicle is greater than the acceleration threshold for exiting; When any of conditions 1) to 4) are met, the frequent shift function trigger flag is set to OFF, and the transmission controller returns to normal control logic.

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