A low-temperature gear selection control method for a light truck ATM automatic transmission

Abstract

The present application relates to a kind of light truck ATM automatic gearbox low temperature selection control method, in low temperature state, trigger the identification condition of this control, and after control trigger, by actively removing electric cylinder force, only by spring force let selection position return to initial position, select target position from initial position, if again appear the phenomenon beyond target position, then let selection return to initial position again, then by the way of percentage reduction electric cylinder force, reselect from initial position start selection.The control method provided in the application mainly solves the problem that the selection of commercial vehicle AMT gearbox fails or selection timeout in low temperature state, resulting in vehicle power interruption and unable to travel.

Description

Technical Field

[0001] This invention belongs to the field of transmission control technology, specifically relating to a low-temperature gear selection control method for a light truck ATM automatic transmission. Background Technology

[0002] Currently, the mainstream AMT transmission structure for light trucks is mainly based on a hydraulically controlled wet multi-plate single clutch and an electric cylinder-controlled shifting actuator. Its main structure generally includes a wet multi-plate single clutch, transmission gears, input shaft, output shaft, housing, lubricating oil, hydraulic module, electric cylinder, shifting actuator, sensors, and TCU electronic control unit.

[0003] The main principle of the gear selection and shifting process in the above structure is that after the TCU recognizes the gear change command, it sends a command to the electric cylinder. The electric cylinder then moves the gear selection shift lever, which in turn moves the gear selection shift fork to the target position. First, the gear selection electric cylinder pushes the gear selection lever to reach the target gear position. Then, the shifting electric cylinder pushes the shifting lever, which in turn pushes the shift fork to the gear position. This part of the control is similar to shifting gears in a manual transmission. First, the shift lever is moved horizontally to the target gear position, and then the shift lever is pushed forward or backward to reach the target gear position.

[0004] The main principle of the gear shifting process is that after the TCU recognizes the gear shifting command, it sends a corresponding command to the shift cylinder, which pushes the shift cylinder to make the gear shift reach the intermediate position. At this time, the gear selector has not yet reached the initial position. After reaching the intermediate position, the gear selector is automatically pushed back to the initial position by the return spring. Therefore, in the gear shifting control process, the shift is pushed to the neutral position by the electric cylinder, while the gear selector is automatically pushed back to the initial position by the return spring.

[0005] The above describes the working principle of the gear shifting actuator. In practical applications, because the gear shifting paddle is surrounded by lubricating oil, the viscosity of the lubricating oil decreases in low-temperature environments, resulting in increased resistance to the movement of the paddle. This has a significant impact on both forward and reverse directions. In the forward direction, a larger electric cylinder force is required to push the gear shifting paddle to the target position, and in the reverse direction, the time to return to the initial position becomes longer. Therefore, the system exhibits differences in gear selection control under normal and low-temperature conditions. Control is more difficult in low-temperature conditions, which can easily lead to incomplete gear selection or gear selection timeout, causing the transmission to fail to engage or disengage gears, thus rendering the vehicle unable to move. Summary of the Invention

[0006] The purpose of this invention is to provide a low-temperature gear selection control method for AMT automatic transmissions in light trucks, in order to solve the problem of gear selection failure or gear selection timeout in commercial vehicles under low-temperature conditions, which leads to power interruption and inability to drive.

[0007] To achieve the above objectives, this application employs the following technical solution:

[0008] A method for low-temperature gear selection control of a light truck ATM automatic transmission includes the following steps:

[0009] S1. Identify the conditions that trigger this control method;

[0010] S2. After this control method is triggered, the force of the gear selection electric cylinder is reduced to 0, so that the gear selection position returns to the initial position.

[0011] S3. Set the standard gear selection electric cylinder force required to reach the target position from the initial position. When the target position is reached and the position is maintained for the set time, the gear selection is successful.

[0012] If the actual position reached under the standard selection cylinder force does not reach the target position, the selection cylinder force is increased until the target position is reached, and the position is maintained at this position for a set time to complete the selection.

[0013] If the actual position exceeds the target position, proceed to step S4;

[0014] S4. Return to step S2, reduce the gear selection electric cylinder force to 0, return the gear selection position to the initial position, reduce the standard gear selection electric cylinder force in step S3 by a determined percentage, and if the target position is reached and maintained in this position for a set time, the gear selection is successful.

[0015] If the actual position is not at the target position, increase the selection force of the selection cylinder until the target position is reached, and maintain it at this position for a set time to complete the selection.

[0016] If the actual position exceeds the target position, repeat this step until the target position is reached;

[0017] If the number of repetitions exceeds the set number, the selection is considered to have failed.

[0018] Furthermore, the conditions for triggering this control method are:

[0019] S11. The ambient temperature or transmission oil temperature is detected to be lower than the set value;

[0020] S12, select gears from high gear to low gear or from low gear to high gear.

[0021] Furthermore, the gear selection position in the control process exceeds the target gear position and is greater than the set value.

[0022] Furthermore, in step S2, it is determined that the gear selection position returns to the initial position by the time the gear selection position is less than the set value, or the time when the gear selection electric cylinder force drops to 0 exceeds the set value.

[0023] Furthermore, in step S4, the percentage value = displacement value exceeding the target / total gear selection stroke.

[0024] Furthermore, in step S4, the number of repetitions does not exceed 4.

[0025] Furthermore, it also includes ensuring that the entire control process is completed within a specified time; if the specified time is exceeded, the gear selection is considered a failure.

[0026] The beneficial effects of this invention are:

[0027] The control method provided in this application mainly solves the problem of commercial vehicle AMT transmission failing to select gears or exceeding the selection time under low temperature conditions, resulting in vehicle power interruption and inability to drive. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the gear position layout of a 6-speed AMT transmission with an electric cylinder-driven gear shifting mechanism. Detailed Implementation

[0029] The technical solution of the present invention will be described in detail below. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solution of the present invention, and should not be construed as limiting the technical solution of the present invention.

[0030] This application provides a low-temperature gear selection control method for a light truck ATM automatic transmission, combined with a 6-speed AMT transmission with an electric cylinder-driven gear shifting actuator, such as... Figure 1 As shown, the main technical solutions are described below:

[0031] S1. Identify the conditions that trigger this control method:

[0032] 1) Low temperature condition detected, the ambient temperature or transmission oil temperature is lower than the set value;

[0033] 2) Gear selection: from high gear to low gear, for example... Figure 1 When shifting from 6th gear to 5th gear;

[0034] 3) When shifting gears from a low gear to a high gear, if the gear selection position exceeds the target gear position and is greater than the set value during the control process, such as shifting from 1st gear to 2nd gear, the gear selection position should reach gear selection position 1 from the initial position. However, if the gear selection position reaches or exceeds gear selection position 1 + the set value during the control process, only one of steps 2) or 3) needs to be satisfied.

[0035] S2. Control measures triggered by this control method:

[0036] 1) When the force of the electric cylinder for gear selection is reduced to 0, the gear selection position will quickly return to the initial position due to the action of only the spring force.

[0037] 2) To determine whether to return to the initial position, the gear selection position is less than the set value (when the initial gear selection position is reached) or the time for the gear selection electric cylinder force to drop to 0 exceeds the set value (e.g., 300ms);

[0038] At this point, the gear selection position returns to the initial position. The next step is to select gears from the low position to the high position. This process can be achieved by actively adjusting the electric cylinder force to adjust the electric cylinder position.

[0039] S3. Select gear from the initial position:

[0040] Initially, the selection electric cylinder is set with the standard selection force (software calibrated quantity) required to reach the target position from the initial position. When the target position is reached and the position is maintained for the set time, the selection is successful.

[0041] If the actual position reached under the standard selection cylinder force does not reach the target position, the selection cylinder force is increased until the target position is reached, and the position is maintained at this position for a set time to complete the selection.

[0042] If the actual position exceeds the target position, proceed to step S4;

[0043] S4. After returning to the initial position for the second time, continue selecting gears from the initial position:

[0044] Return to step S2, reduce the force of the gear selection electric cylinder to 0, return the gear selection position to the initial position, and reduce the standard gear selection electric cylinder force in step S3 by a determined percentage. This percentage depends on the ratio of the displacement of the gear selection electric cylinder beyond the target position in step S3 to the total gear selection stroke, that is, percentage value = displacement beyond the target / total gear selection stroke.

[0045] If the target position is reached and the position is maintained for the set time, the gear selection is successful;

[0046] If the actual position is not at the target position, increase the selection force of the selection cylinder until the target position is reached, and maintain it at this position for a set time to complete the selection.

[0047] If the actual position exceeds the target position, repeat step S4 until the target position is reached. This process should not be repeated more than four times; if it exceeds four times, the selection of the desired location is considered a failure.

[0048] The entire control process in this application must be completed within a specified time. If the specified time is exceeded (e.g., the time is greater than 2000ms), the selection will still fail.

[0049] The above embodiments illustrate the structure, features, and effects of the present invention in detail. The above descriptions are merely preferred embodiments of the present invention, but the present invention does not limit the scope of implementation. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification, should be within the protection scope of the present invention.

Claims

1. A low-temperature gear selection control method for a light truck ATM automatic transmission, characterized in that, Includes the following steps: S1. Identify the conditions that trigger this control method; S2. After this control method is triggered, the force of the gear selection electric cylinder is reduced to 0, so that the gear selection position returns to the initial position. S3. Set the standard gear selection electric cylinder force required to reach the target position from the initial position. When the target position is reached and the position is maintained for the set time, the gear selection is successful. If the actual position reached under the standard selection cylinder force does not reach the target position, the selection cylinder force is increased until the target position is reached, and the position is maintained at this position for a set time to complete the selection. If the actual position exceeds the target position, proceed to step S4; S4. Return to step S2, reduce the gear selection electric cylinder force to 0, return the gear selection position to the initial position, reduce the standard gear selection electric cylinder force in step S3 by a determined percentage, and if the target position is reached and maintained in this position for a set time, the gear selection is successful. If the actual position is not at the target position, increase the selection force of the selection cylinder until the target position is reached, and maintain it at this position for a set time to complete the selection. If the actual position exceeds the target position, repeat this step until the target position is reached; If the number of repetitions exceeds the set number, the selection is considered to have failed; The conditions for triggering this control method are: S11. The ambient temperature or transmission oil temperature is detected to be lower than the set value; S12, select gears from high gear to low gear or from low gear to high gear.

2. The low-temperature gear selection control method for a light truck ATM automatic transmission according to claim 1, characterized in that, The gear selection position during the control process exceeds the target gear position and is greater than the set value.

3. The low-temperature gear selection control method for a light truck ATM automatic transmission according to claim 1, characterized in that, In step S2, it is determined that the gear selection position returns to the initial position when the gear selection position is less than the set value, or when the time for the gear selection electric cylinder force to drop to 0 exceeds the set value.

4. The low-temperature gear selection control method for a light truck ATM automatic transmission according to claim 1, characterized in that, In step S4, the percentage value = displacement value exceeding the target / total gear selection stroke.

5. The low-temperature gear selection control method for a light truck ATM automatic transmission according to claim 1, characterized in that, In step S4, the number of repetitions shall not exceed 4.

6. The low-temperature gear selection control method for a light truck ATM automatic transmission according to claim 1, characterized in that, It also includes ensuring that the entire control process is completed within a specified time; if the specified time is exceeded, the gear selection is considered a failure.

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