A method for controlling AMT clutch separation timing

Abstract

This invention provides an AMT clutch disengagement timing control method, relating to the field of clutch disengagement control. The solution includes the following steps: S01: During vehicle operation, when the shifting conditions are met (defined as time t1), the engine output torque T at this time is recorded. e S02: Determine the target torque reduction value T for the engine. t The torque reduction slope K of the engine e Engine reduced to T t Required time, clutch slow disengagement slope K c The moment of rapid clutch disengagement t c , the time t when the disengagement action is performed g S03: The engine is based on the torque reduction slope K. e Reduce to target torque to T t Meanwhile, the clutch disengages slowly at a slope K. c Separation; S04: When the clutch is rapidly disengaged, t c The clutch disengages rapidly, and the moment t is reached when the gear disengagement action is performed. g The shift actuator performs disengagement. This invention reduces the computational complexity of the vehicle controller, ensures the clutch disengages at the precise moment, and improves shifting comfort.

Description

Technical Field

[0001] This invention relates to the field of clutch disengagement control, and more particularly to an AMT clutch disengagement timing control method. Background Technology

[0002] An automated manual transmission (AMT) is a modified manual transmission with an automatic shifting mechanism and a clutch assist mechanism to achieve automatic control of vehicle starting and shifting. AMT not only inherits the advantages of high efficiency, low cost, and high reliability of manual transmission, but also greatly improves the ease of vehicle operation. When starting, accelerating, or decelerating, the clutch needs to be disengaged.

[0003] To reduce the jerking sensation during gear shifts and improve driving shifting comfort, existing technologies control engine torque reduction, clutch disengagement, and gear shifting sequentially. The control unit adjusts and calibrates multiple related control parameters individually, such as clutch disengagement slope, engine torque reduction slope, and clutch-engine matching timing, so that the clutch disengages at the appropriate time.

[0004] The above technical solutions can reduce the jerking sensation to some extent. However, under different shifting conditions, multiple parameters such as clutch disengagement slope, engine torque reduction slope, and clutch-engine matching timing need to be calibrated according to different engine torque transmission conditions. Furthermore, repeated adjustments are required to ensure that multiple parameters are matched to guarantee that the clutch disengages at the appropriate time. The calibration logic is unclear and the calibration is cumbersome. At the same time, the sequential execution of engine torque reduction, clutch disengagement, and gear disengagement prolongs the shifting time. Summary of the Invention

[0005] To address the technical problems of long shift times and complex calibration logic in existing vehicle gear shifting technologies, this invention provides an AMT clutch disengagement timing control method. This method reduces the computational load and workload of the transmission controller, ensures clutch disengagement at the appropriate time, avoids shift jerking, and significantly shortens shift time.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: an AMT clutch disengagement timing control method, comprising the following steps:

[0007] S01: During vehicle operation, when the shifting conditions are met, this moment is defined as time t1. Record the engine's output torque T at this moment. e ;

[0008] S02: Determine the target torque reduction value T for the engine. t The torque reduction slope K of the engine e Engine reduced to Tt Required time, clutch slow disengagement slope K c The moment of rapid clutch disengagement t c , the time t when the disengagement action is performed g ,in,

[0009]

[0010] t c = t1 + Δt - Δt c , t g = t1 + Δt - Δt g ,

[0011]

[0012] T c For t c The input torque of the clutch driven plate at time t1 is given by the slope K. e The gear ratio is selected based on the throttle opening, clutch input torque, and gear ratio at the time of the shift request. Δt c The constant value is determined by the clutch's mechanical response characteristics, referring to the time Δt taken from requesting rapid clutch disengagement to the clutch reaching the semi-engaged point. g The set value is determined by the mechanical response characteristics of the gear shifting actuator, referring to the time from issuing the disengagement signal to the gear returning to neutral, T. f J represents the engine friction torque. e θ represents the equivalent rotational inertia of engine components, and θ represents the angular displacement of the engine flywheel.

[0013] S03: Engine according to torque reduction slope K e Reduce to target torque to T t Meanwhile, the clutch disengages slowly at a slope K. c Separation;

[0014] S04: When the clutch reaches its rapid disengagement moment t c The clutch disengages rapidly, and the moment t is reached when the gear disengagement action is performed. g The gear shifting actuator performs the disengagement.

[0015] By setting a target torque and performing clutch disengagement and shifting during engine torque reduction, the clutch can be disengaged at zero torque input, ensuring torque balance during shifting, avoiding shift jerks, and reducing the number of calibrated control parameters. During engine torque reduction, the clutch is simultaneously controlled to slowly disengage to torque T. c The corresponding position not only enables the clutch assist mechanism to act in advance, avoiding serious response delays when requesting rapid disengagement, but also greatly shortens the shifting time.

[0016] Furthermore,

[0017] K e =k*T e *k a *k g ,

[0018] k is a constant and is determined by the engine output torque T. e The engine output torque T is determined. e The correspondence between k and k is predefined, k a With k g These are the throttle opening coefficient and gear ratio coefficient used to calculate and select the torque reduction slope.

[0019] The torsional slope K is determined using this formula. e It can more accurately match the driver's driving intentions and road conditions.

[0020] Furthermore, T1 is the maximum input torque of the clutch.

[0021] Furthermore,

[0022] T c =T t +ΔT

[0023] In the formula, ΔT is calibrated according to the torque transmission characteristics of the clutch.

[0024] Setting the input torque for quick clutch disengagement to be greater than the engine's torque reduction target ensures that the clutch has sufficient capacity to fully transmit the engine's output torque during the simultaneous process of engine torque reduction and slow clutch disengagement, thus avoiding jerking sensations caused by large changes in vehicle power.

[0025] As can be seen from the above technical solutions, the present invention has the following advantages:

[0026] This invention provides an AMT clutch disengagement timing control method. By setting a target torque and performing clutch disengagement and shifting actions during engine torque reduction, the clutch can be disengaged at zero torque input, ensuring torque balance during shifting, avoiding shift jerks, and reducing the number of calibrated control parameters. During engine torque reduction, the clutch is synchronously controlled to slowly disengage to torque T. c The corresponding position not only allows the clutch booster mechanism to act earlier, avoiding severe response delays when requesting rapid disengagement, but also greatly shortens shift time; the torque reduction slope K is determined by formula. eIt can more accurately match the driver's driving intentions and road conditions; multiple components operate in parallel, and clutch requests and disengagement requests are issued during engine torque reduction, fully considering the mechanical response characteristics of the actuator, which is beneficial to shorten the shift time; setting the input torque when the clutch requests rapid disengagement to be greater than the engine's torque reduction target value can ensure that the clutch has sufficient capacity to transmit the engine's output torque during the simultaneous process of engine torque reduction and clutch disengagement, avoiding large changes in the vehicle's power that cause a jerking sensation. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram illustrating the application of a specific embodiment of the present invention.

[0029] Figure 2 This is a flowchart illustrating a specific embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0031] The vehicle drivetrain is an elastic system. The inventors discovered that when the clutch disengages at high engine torque, the torque transmitted by the clutch is large, which can easily cause the vehicle to decelerate suddenly, resulting in jerking. Conversely, when the clutch disengages with lag, the engine is at zero torque, creating a drag braking effect on the vehicle. After disengagement, the elastic potential energy stored in the driven plate is released, causing the input shaft speed to increase, resulting in a jolt to the vehicle. Disengagement at either high or zero engine torque leads to poor driver comfort. Therefore, regardless of whether the clutch disengages at high or zero engine torque, there is a significant torque before or after disengagement, causing a jerking sensation. Thus, the inventors creatively disengaged the clutch at zero torque input to the driven plate. Since the input torque to the driven plate is zero at this time, it does not affect vehicle speed and avoids jerking.

[0032] because

[0033]

[0034] In the formula, T represents the input torque of the clutch driven plate. e T represents the engine's output torque. f J represents the engine friction torque. e Let θ represent the equivalent moment of inertia of the engine, and θ represent the angular displacement of the engine flywheel. Therefore, in order to ensure that the input torque of the driven plate can be reduced to zero when the clutch is fully disengaged, the inventors have adopted a further technical concept: reducing the output torque of the engine, thereby gradually reducing the input torque of the clutch driven plate to zero. Let the target torque reduction value T be the reduction in engine input torque when the clutch has zero input torque. t That is, satisfying the following formula:

[0035]

[0036] At this point, the target value for torque reduction is T. t As a custom design, it is determined by the inherent mechanical characteristics of the engine. Considering the time required for clutch disengagement, the engine torque needs to be reduced to T. t Previously, a command to disengage the clutch was issued; at the same time, in order to shorten the clutch disengagement time and the duration of power interruption of the entire vehicle, the inventors creatively divided the clutch disengagement process into slow disengagement and fast disengagement.

[0037] Based on the above analysis, such as Figure 1 and Figure 2 As shown in the figure, this specific embodiment provides an AMT clutch disengagement timing control method, including the following steps:

[0038] S01: During vehicle operation, when the shifting conditions are met, this moment is defined as time t1. Record the engine's output torque T at this moment. e ;

[0039] S02: Determine the target torque reduction value T for the engine. t The torque reduction slope K of the engine e Engine reduced to T t Required time, clutch slow disengagement slope K c The moment of rapid clutch disengagement t c , the time t when the disengagement action is performed g ,in,

[0040]

[0041] t c = t1 + Δt - Δt c , t g = t1 + Δt - Δt g ,

[0042]

[0043] T c For t c The input torque of the clutch driven plate at time t1 is given by the slope K. e The gear ratio is selected based on the throttle opening, clutch input torque, and gear ratio at the time of the shift request. Δt c The constant value is determined by the clutch's mechanical response characteristics, referring to the time Δt taken from requesting rapid clutch disengagement to the clutch reaching the semi-engaged point. g The set value is determined by the mechanical response characteristics of the gear shifting actuator, referring to the time from issuing the disengagement signal to the gear returning to neutral, T. f J represents the engine friction torque. e θ represents the equivalent rotational inertia of engine components, and θ represents the angular displacement of the engine flywheel.

[0044] S03: Engine according to torque reduction slope K e Reduce to target torque to T t Meanwhile, the clutch disengages slowly at a slope K. c Separation;

[0045] S04: When the clutch reaches its rapid disengagement moment t c The clutch disengages rapidly, and the moment t is reached when the gear disengagement action is performed. g The gear shifting actuator performs the disengagement.

[0046] By setting a target torque and implementing clutch disengagement and shifting actions during engine torque reduction, and completing clutch disengagement and shifting when the engine torque drops to the target torque, clutch disengagement at zero torque input can be achieved. This ensures torque balance during gear shifting, prevents sudden speed drops, and avoids long power interruption times caused by delayed start-up of the gear shifting actuator under sequential control. Furthermore, by logically correlating the engine torque reduction slope with the slow clutch disengagement slope, compared to calibrating multiple control parameters independently, the number of calibrated control parameters can be reduced, avoiding multiple adjustments and significantly reducing the computational load on the control unit. In this specific embodiment, the main purpose of the slow clutch disengagement action is to activate the clutch assist mechanism during the engine torque reduction phase, facilitating subsequent rapid disengagement and avoiding long power interruption times caused by delayed start-up of the mechanical structure under sequential control. This specific embodiment is described according to a linear clutch request; similarly, the slow clutch disengagement action can also be adapted to a non-linear request based on the adaptive results of the clutch torque transmission characteristics.

[0047] In S02,

[0048] K e =k*Te *k a *k g ,

[0049] k is a constant and is determined by the engine output torque T. e The engine output torque T is determined. e The correspondence between k and k is predefined, k a With k g These steps involve calculating the throttle opening coefficient and gear ratio coefficient to select the torque reduction slope; and then determining the torque reduction slope K using a formula. e It can more accurately match the driver's driving intentions and road conditions, that is, it selects a larger torque reduction slope when the throttle opening is larger, the clutch input torque is larger, and the driving gear is higher.

[0050] In S02, T1 is the maximum input torque of the clutch.

[0051] To ensure that the clutch has sufficient capacity to transmit the engine's output torque during the simultaneous reduction of engine torque and clutch disengagement, and to avoid a jerking sensation caused by the vehicle's power not changing linearly with the engine power, in this specific implementation,

[0052] T c =T t +ΔT

[0053] In the formula, ΔT is calibrated according to the torque transmission characteristics of the clutch.

[0054] As can be seen from the above specific embodiments, the present invention has the following beneficial effects:

[0055] 1. By setting a target torque and performing clutch disengagement and shifting during engine torque reduction, the clutch can be disengaged at zero torque input, ensuring torque balance during shifting, avoiding shift jerks, and reducing the number of calibrated control parameters. During engine torque reduction, the clutch is simultaneously controlled to slowly disengage to torque T. c The corresponding position not only enables the clutch booster mechanism to act in advance, avoiding serious response delays when requesting rapid disengagement, but also greatly shortens the shifting time;

[0056] 2. Determine the torsional slope K using the formula. e It can more accurately match the driver's driving intentions and road conditions;

[0057] 3. Multiple components operate in parallel, and clutch and disengagement requests are issued during engine torque reduction, which fully considers the mechanical response characteristics of the actuator and helps to shorten shift time;

[0058] 4. Setting the input torque when the clutch requests rapid disengagement to be greater than the engine's torque reduction target value ensures that the clutch has sufficient capacity to transmit the engine's output torque during the simultaneous process of engine torque reduction and clutch disengagement, avoiding large changes in vehicle power that could cause jerking.

[0059] 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 method for controlling the disengagement timing of an AMT clutch, characterized in that, Includes the following steps: S01: During vehicle operation, when the shifting conditions are met, this moment is defined as time t1. Record the engine's output torque T at this moment. e ; S02: Determine the target torque reduction value T for the engine. t The torque reduction slope K of the engine e Engine reduced to T t Required time, clutch slow disengagement slope K c The moment of rapid clutch disengagement t c , the time t when the disengagement action is performed g ,in, t c =t1+Δt-Δt c ,t g =t1+Δt-Δt g , T c For t c The input torque of the clutch driven plate at time t1 is given by the slope K. e Δt is selected based on the throttle opening, clutch input torque, and gear ratio at the time of the shift request. c The constant value is determined by the clutch's mechanical response characteristics, referring to the time Δt taken from requesting rapid clutch disengagement to the clutch reaching the semi-engaged point. g The set value, T, is determined by the mechanical response characteristics of the gear shifting actuator and refers to the time from issuing the disengagement signal to the gear returning to neutral. f J represents the engine friction torque. e θ represents the equivalent rotational inertia of engine components, and θ represents the angular displacement of the engine flywheel. S03: Engine according to torque reduction slope K e Reduce to target torque to T t Meanwhile, the clutch disengages slowly at a slope K. c Separation; S04: When the clutch reaches its rapid disengagement moment t c The clutch disengages rapidly, and the moment t is reached when the gear disengagement action is performed. g The gear shifting actuator performs the disengagement.

2. The AMT clutch disengagement timing control method as described in claim 1, characterized in that, K e =k*T e *k a *k g , k is a constant and is determined by the engine output torque T. e The engine output torque T is determined. e The correspondence between k and k is predefined, k a With k g These are the throttle opening coefficient and gear ratio coefficient used to calculate and select the torque reduction slope.

3. The AMT clutch disengagement timing control method as described in claim 1, characterized in that, T1 is the maximum input torque of the clutch.

4. The AMT clutch disengagement timing control method as described in claim 3, characterized in that, T c =T t +ΔT In the formula, ΔT is calibrated according to the torque transmission characteristics of the clutch.

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