AMT gearbox control method, system and equipment in braking state and medium

Abstract

The invention relates to the technical field of AMT gearbox control, in particular to an AMT gearbox control method, system and equipment in a braking state and a medium, and the method comprises the steps that when a vehicle is in a braking deceleration state, the stepping duration of a brake pedal, the actual vehicle speed, the actual acceleration of the vehicle and the rotating speed of an engine are obtained; whether the braking intention of the driver is emergency braking or stable braking is judged based on the stepping duration of the brake pedal and the actual acceleration of the vehicle; and based on the braking intention, the gear of the AMT gearbox and the separation state of a clutch are controlled till braking is finished. Wherein the current gear is maintained during emergency braking, and a clutch is controlled to be separated according to an engine rotating speed threshold value; during stable braking, after the rotating speed of the engine meets the condition, whether downshift is conducted or not is judged according to the actual vehicle speed, and a clutch is controlled to be separated. The brake intention of a driver can be accurately recognized, differential control is executed, and therefore the brake efficiency is effectively improved, engine flameout is prevented, and the driving smoothness is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of AMT gearbox control, in particular to an AMT gearbox control method, system, device and medium in braking state. BACKGROUND

[0002] With the continuous improvement of the automation and intelligence level of commercial vehicles, AMT gearbox (i.e. automatic mechanical transmission) has significantly improved its popularity in the field of commercial vehicles due to its advantages such as solid structure and high transmission efficiency. AMT gearbox automatically performs clutch and gear shifting operations through TCU (electronic control unit) to improve driving convenience and power transmission efficiency. In actual driving, vehicles need to frequently deal with various working conditions such as acceleration, cruising and braking, among which the braking deceleration process has a significant impact on driving safety, energy management and driving quality. Therefore, the coordinated control strategy of AMT system in braking state has become one of the key technical considerations.

[0003] The existing technology usually adopts a sequential downshift strategy based on fixed rules to control the AMT gearbox during the vehicle braking deceleration process. Specifically, when the brake pedal signal is detected, the control system will instruct the gearbox to sequentially reduce the gear position according to the preset logical conditions (such as the vehicle speed or engine speed falling below a certain threshold); at the same time, the clutch will perform a disengagement action according to another set of preset speed or vehicle speed thresholds, the core purpose of which is to use engine braking to assist vehicle deceleration and cut off power transmission before the engine speed is too low to prevent engine stall.

[0004] However, the existing ATM gearbox control method in the deceleration process has obvious deficiencies: since a single and fixed downshift and clutch control logic is used for all braking scenarios, the existing method cannot identify and respond to the actual braking intention differences of the driver in different situations, which may delay the optimal braking opportunity and affect the braking response efficiency when emergency braking is needed, and the fixed clutch disengagement threshold may not effectively prevent engine stall in rapidly changing dynamics; when performing smooth braking, unnecessary sequential downshift may cause frequent power interruptions, affecting the smooth utilization of engine braking effect and driving comfort, and it is difficult to balance braking efficiency and ride quality. SUMMARY

[0005] In view of the technical problem that the existing ATM gearbox control method in the deceleration process does not distinguish the braking intention of the driver and uses a single control logic, which makes it difficult to balance braking efficiency, engine anti-stall protection and driving smoothness in different scenarios of emergency braking and smooth braking, the present application provides an AMT gearbox control method, system, device and medium in braking state, which improves braking efficiency, engine anti-stall ability and driving smoothness by judging the braking intention in real time and performing differentiated gear and clutch control according to the braking intention.

[0006] In a first aspect, this application provides an AMT transmission control method under braking conditions, comprising the following steps: S1. When the vehicle is in a braking and deceleration state, obtain the duration of the brake pedal being pressed, the actual vehicle speed, the actual vehicle acceleration, and the engine speed; S2. Determine the driver's braking intention based on the duration of brake pedal depressing and the actual vehicle acceleration; Specifically, if the actual acceleration of the vehicle is lower than the acceleration threshold corresponding to the current duration of the brake pedal being depressed, the braking intention is determined to be emergency braking; otherwise, the braking intention is determined to be smooth braking. The acceleration threshold is a pre-calibrated value, and the acceleration threshold is <0. S3. Based on the braking intention, control the gear position and clutch disengagement state of the AMT transmission until the braking ends; If the braking intention is emergency braking, the current gear of the AMT transmission is maintained, and the clutch is controlled to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2, where Thd1>Thd2. If the braking intention is smooth braking, then when the engine speed meets the preset conditions, the current actual vehicle speed is compared with the preset vehicle speed threshold. Based on the comparison result, it is determined whether to perform a downshift operation and control the clutch to disengage.

[0007] It should be further explained that in step S1, when the control unit of the AMT transmission receives a braking signal, it determines that the vehicle is in a braking and deceleration state.

[0008] It should be further noted that the acceleration threshold calibration step in step S2 includes: Multiple sets of real vehicle braking tests were performed under different conditions. Each set of real vehicle braking tests included a complete braking process using a real vehicle, and the duration of brake pedal depressing and the actual vehicle acceleration during the braking process were collected as sample data for that set of real vehicle braking tests. Based on sample data showing that the driver's actual braking intention is emergency braking, the critical value of the vehicle's actual acceleration is determined for different brake pedal depress durations, and this critical value is calibrated as the acceleration threshold corresponding to that level of brake pedal depress duration.

[0009] It should be further noted that in step S2, when the brake pedal is depressed for ≤0.5s, the corresponding acceleration threshold is -2.5m / s². 2 ; When the brake pedal is depressed for more than 0.5 seconds, the corresponding acceleration threshold is -6 m / s². 2 .

[0010] It should be further noted that in step S3, the value range of the first engine speed threshold Thd1 is 850-1050 rpm; The second engine speed threshold Thd2 ranges from 550 to 750 rpm.

[0011] It should be further explained that, in step S3, controlling the clutch to perform the disengagement action based on the comparison relationship between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2 specifically includes: When the engine speed is higher than Thd1, the clutch is kept engaged. When the engine speed is between Thd2 and Thd1, the clutch is controlled to disengage at a preset disengagement slope; When the engine speed is below Thd2, the travel of the clutch release bearing is controlled to reach the preset critical travel, and then the real-time clutch requested torque is calculated and controlled. until the clutch is fully disengaged; Real-time clutch torque request The calculation formula is:

[0012] in, This indicates the pre-calibrated engine torque proportionality coefficient; This indicates the engine's real-time output torque; Indicates the real-time engine speed; Indicates based on real-time engine speed Determined engine speed weighting coefficient; This represents the weighting coefficient for the pre-calibrated input shaft speed descent slope. This represents the absolute value of the slope of the input shaft speed decrease. Represents the absolute value of the rate of change of engine speed; Represents the absolute value of the rate of change of engine torque; This represents the dynamic attenuation gain determined based on the absolute values ​​of the engine speed change rate and the engine torque change rate.

[0013] It should be further explained that the critical stroke is specifically: the position reached by the clutch release bearing after it has reached the clutch KP point, and then shifted in the direction of increasing the clutch release stroke by a preset offset amount.

[0014] It should be further noted that the preset offset value ranges from 3% to 8% of the total separation stroke of the release bearing.

[0015] It should be further explained that, The calculation formula is:

[0016] in, This represents the initial gain, with a value ranging from 0.8 to 1.0. This represents the attenuation factor, with a value range of 0.0001-0.0002; This represents the minimum offset, with a value ranging from 0.2 to 0.4. Bench simulation tests at different speeds are required to measure and obtain the optimal results. , , Matching relationship; The calculation formula is:

[0017] in, This represents the weight of the rate of change of rotational speed, with a value range of 0.0002-0.0005; This represents the weight of the torque change rate, with a value ranging from 0.001 to 0.003. Bench simulation tests simulating engine speed and torque are required for adjustment. and This allows for a smooth transition of the torque requested by the clutch.

[0018] It should be further noted that the real-time clutch requests torque The rate of change must be satisfied, specifically: within a unit time step Internally, the real-time clutch requests torque. Change satisfy:

[0019] This indicates the preset limit for the rate of change of clutch requested torque.

[0020] It should be further explained that, The value ranges from 0.3 to 0.8; The value needs to be determined through actual vehicle testing and must meet the following conditions: The driver experienced no noticeable impact, no abnormal noises during gear shifting, and no body swaying caused by sudden torque changes during braking.

[0021] It should be further explained that in step S3, when the braking intention is smooth braking, the engine speed meets the preset condition, which means that the engine speed is lower than the sum of the engine idle speed and the preset speed compensation value.

[0022] It should be further noted that the speed compensation value is 50-150 rpm.

[0023] It should be further explained that in step S3, the current actual vehicle speed is compared with the preset vehicle speed threshold. Based on the comparison result, it is determined whether to perform a downshift operation and the clutch is disengaged. Specifically, this includes: S301. Compare the current actual vehicle speed with the preset vehicle speed threshold; S302. If the current actual vehicle speed is higher than the preset vehicle speed threshold, then perform a downshift operation; after the downshift operation is completed, return to step S301; If the current actual vehicle speed is not higher than the preset vehicle speed threshold, the current gear will be maintained and the clutch will be fully disengaged.

[0024] It should be further explained that the method for determining the preset vehicle speed threshold is as follows: The maximum permissible vehicle speed without drag is calculated by using engine idle speed, the highest speed ratio of the low gear of the transmission, and the rear axle ratio, and is used as the preset vehicle speed threshold.

[0025] It should be further noted that the preset vehicle speed threshold ranges from 8 to 15 km / h. It should be further noted that in step S302, the target gear for downshifting is determined based on the engine's economic speed and the current actual vehicle speed, specifically including: Find the engine speed range covered by the lowest fuel consumption rate under the real-time output torque condition in the engine universal characteristic curve, and define the engine speed range as the economic speed range of the engine under the current operating conditions. Within the engine's economic speed range, the engine speed value closest to the real-time engine speed is selected as the target engine speed. ; Based on the current actual vehicle speed and target engine speed Calculate the target speed ratio The calculation formula is:

[0026] in, Indicates the rolling radius of the wheel; This represents a fixed calibration constant used for converting units of rotational speed and vehicle speed; Indicates the final drive ratio; Based on the gear ratio values ​​of each gear in the AMT transmission, select the gear that is closest to the target gear ratio as the target gear.

[0027] Among them, the universal characteristic curve of the engine has engine speed as the horizontal axis and engine torque as the vertical axis, superimposed with the fuel consumption rate contour line.

[0028] Secondly, this application provides an AMT transmission control system under braking conditions, used to implement the above-mentioned AMT transmission control method, including: The data acquisition module is used to acquire the duration of the brake pedal being depressed, the actual vehicle speed, the actual vehicle acceleration, and the engine speed when the vehicle is in a braking and deceleration state. The braking intention determination module is used to determine the driver's braking intention based on the duration of the brake pedal being depressed and the actual acceleration of the vehicle. If the actual acceleration of the vehicle is lower than the acceleration threshold corresponding to the current duration of the brake pedal being depressed, the braking intention is determined to be emergency braking; otherwise, the braking intention is determined to be smooth braking. The emergency braking control module is used to maintain the current gear of the AMT transmission when the braking intention is emergency braking, and to control the clutch to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2, where Thd1>Thd2. The smooth braking control module is used to compare the current actual vehicle speed with a preset vehicle speed threshold when the engine speed meets the preset conditions, and to determine whether to perform a downshift operation based on the comparison result, and to control the clutch to disengage.

[0029] Thirdly, this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described AMT transmission control method.

[0030] Fourthly, this application provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described AMT transmission control method.

[0031] As can be seen from the above technical solutions, this application has the following advantages: 1. This application obtains the duration of brake pedal depressing and the actual acceleration of the vehicle to determine the driver's braking intention, and controls the gearbox gear and clutch disengagement state based on the differences in braking intention. This achieves refined and adaptive management of braking and deceleration conditions, overcomes the shortcomings of existing technologies that use a single control logic and cannot adapt to different braking scenarios, and significantly improves the coordination, safety and driving smoothness of the braking process as a whole.

[0032] 2. This application introduces a joint judgment mechanism based on the duration of brake pedal depressing and the actual vehicle acceleration, which can accurately distinguish between the driver's emergency braking intention and smooth braking intention. This directly addresses the shortcomings of existing technologies in effectively identifying differences in braking intentions, enabling the control system to obtain a more accurate qualitative judgment of the current braking condition. This lays a reliable foundation for subsequently implementing differentiated control strategies and ensures that the control objectives match the driver's actual needs.

[0033] 3. For scenarios deemed as emergency braking, this application employs a strategy of maintaining the current gear and controlling the clutch disengagement timing in conjunction with engine speed thresholds. This avoids unnecessary downshifting during emergency deceleration, which helps maintain the response speed and efficiency of the braking system. Simultaneously, by setting a first engine speed threshold Thd1 and a second engine speed threshold Thd2 to control the clutch disengagement process in a stepwise manner, timely intervention can be provided when the engine speed drops rapidly. This effectively prevents the risk of engine speed dropping too low or stalling due to excessive power transmission load, thus balancing braking performance and power system protection.

[0034] 4. For scenarios deemed as smooth braking, this application employs a control logic that determines whether to downshift based on a comparison between the actual vehicle speed and a preset vehicle speed threshold after the engine speed meets the required conditions. This allows the vehicle to enhance engine braking and improve deceleration efficiency by downshifting appropriately at higher speeds. When the vehicle speed drops below the threshold, the gear is maintained and the clutch is disengaged, avoiding unnecessary and frequent downshifting at low speeds. The above strategy optimizes the power interruption rhythm and vehicle deceleration curve during smooth braking, improving the smoothness and comfort of driving and riding. Attached Figure Description

[0035] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart of an AMT transmission control method under braking conditions in one embodiment of this application.

[0037] Figure 2 This is a schematic block diagram of an AMT transmission control system under braking conditions in one embodiment of this application.

[0038] Figure 3 This is a schematic diagram of the hardware structure of an electronic device in one embodiment of this application. Detailed Implementation

[0039] To make the purpose, features, and advantages of this application more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solution protected by this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] The AMT transmission control method of this application will be described in detail below. Specific details such as particular system structures and technologies are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0041] In the AMT transmission control method disclosed in this application, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0042] To facilitate a clear description of the technical solutions of this application, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" do not necessarily imply that they are different.

[0043] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0044] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0045] The AMT transmission control method provided in this application embodiment is executed by a computer device, and correspondingly, the AMT transmission control system in the braking state runs in the computer device.

[0046] Figure 1 This is a flowchart of an AMT transmission control method under braking conditions according to an embodiment of this application. Figure 1 The executing entity can be an AMT (Automated Manual Transmission) control system. Depending on the specific requirements, the order of steps in this flowchart can be changed, and some steps can be omitted.

[0047] like Figure 1 As shown, the AMT transmission control method under this braking state includes: Step S1: When the vehicle is in a braking and deceleration state, obtain the duration of the brake pedal being pressed, the actual vehicle speed, the actual vehicle acceleration, and the engine speed.

[0048] By simultaneously acquiring the brake pedal depress duration, actual vehicle speed, actual vehicle acceleration, and engine speed when the vehicle is braking and decelerating, the system covers driver input, vehicle motion status, and real-time power system operating conditions. This enables the control system to fully perceive the transient characteristics of braking, ensuring that the input information for the entire control process is accurate and complete.

[0049] In some specific embodiments, when the control unit of the AMT transmission receives a braking signal, it determines that the vehicle is in a braking and deceleration state.

[0050] When the AMT transmission control unit receives a braking signal, it determines that the vehicle is in a braking and deceleration state. Using the braking signal as a trigger condition, the control system can promptly respond to the driver's braking operation and activate the braking and deceleration control module. This avoids delays or misjudgments that may occur when judging based on other indirect parameters, thereby improving the accuracy and immediacy of the control module's startup and ensuring the smooth startup of subsequent control processes.

[0051] Step S2: Determine the driver's braking intention based on the duration of the brake pedal being depressed and the actual acceleration of the vehicle; Specifically, if the actual acceleration of the vehicle is lower than the acceleration threshold corresponding to the current duration of the brake pedal being depressed, the braking intention is determined to be emergency braking; otherwise, the braking intention is determined to be smooth braking. The acceleration threshold is a pre-calibrated value, and the acceleration threshold is <0. By comparing the actual vehicle acceleration with the pre-calibrated acceleration threshold corresponding to the current brake pedal depress duration based on the duration of brake pedal depressing, the system determines whether the braking intention is emergency braking or smooth braking. By utilizing the dynamic correlation between time and deceleration (acceleration in the opposite direction of travel), the system achieves objective quantitative recognition of the driver's braking intention. This enables the control system to accurately distinguish braking needs of different intensities, providing a precise and reliable logical basis for subsequent execution of differentiated gear and clutch control.

[0052] In some specific embodiments, the calibration step of the acceleration threshold includes: Multiple sets of real vehicle braking tests were performed under different conditions. Each set of real vehicle braking tests included a complete braking process using a real vehicle, and the duration of brake pedal depressing and the actual vehicle acceleration during the braking process were collected as sample data for that set of real vehicle braking tests. Based on sample data showing that the driver's actual braking intention is emergency braking, the critical value of the vehicle's actual acceleration is determined for different brake pedal depress durations, and this critical value is calibrated as the acceleration threshold corresponding to that level of brake pedal depress duration.

[0053] By conducting multiple sets of real-vehicle braking tests under different conditions, sample data of brake pedal depress duration and vehicle actual acceleration were collected. Based on the sample data of actual braking intention as emergency braking, the critical value of vehicle actual acceleration under different brake pedal depress durations was determined as the acceleration threshold. Relying on real driving scenario data, the acceleration threshold can reflect the actual vehicle dynamic characteristics and driver behavior habits, improving the objectivity of the braking intention judgment standard and its fit with actual working conditions, thereby improving the accuracy of the judgment.

[0054] In some specific embodiments, when the brake pedal is depressed for ≤0.5s, the corresponding acceleration threshold is -2.5m / s². 2 ; When the brake pedal is depressed for more than 0.5 seconds, the corresponding acceleration threshold is -6 m / s². 2 .

[0055] By setting specific values ​​for acceleration thresholds, a clear and segmented quantitative standard is provided for judging braking intent. This takes into account the difference in deceleration expectations under short-term deep braking and long-term braking, making emergency braking recognition more consistent with the different modes of rapid braking and gradual braking in actual operation. This enhances the practicality of the judgment logic and its sensitivity to rapid braking scenarios.

[0056] In one specific embodiment, the duration of brake pedal depressing Actual acceleration The correspondence between the braking intention and the braking intention is shown in Table 1.

[0057] Table 1. Correspondence between Braking Intents

[0058] Step S3: Based on the braking intention, control the gear position and clutch disengagement state of the AMT transmission until the braking ends; If the braking intention is emergency braking, the current gear of the AMT transmission is maintained, and the clutch is controlled to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2, where Thd1>Thd2. If the braking intention is smooth braking, then when the engine speed meets the preset conditions, the current actual vehicle speed is compared with the preset vehicle speed threshold. Based on the comparison result, it is determined whether to perform a downshift operation and control the clutch to disengage.

[0059] By controlling the gear position and clutch disengagement of the AMT transmission based on the determined braking intention until the braking ends, the current gear is maintained for emergency braking and the clutch disengagement timing is controlled according to the engine speed threshold. For smooth braking, the downshift and clutch disengagement are determined according to the vehicle speed threshold after the engine speed meets the condition. This makes the control action match the driver's actual intention, optimizes the power transmission and interruption rhythm during the braking process, and thus improves the adaptability to working conditions, braking efficiency and driving smoothness.

[0060] In this scheme, the range of values ​​for Thd1 is typically considered from two perspectives: 1. Keep the engine speed as high as possible, as the engine's inertia can drag the vehicle backward for braking and deceleration; 2. The engine speed should be lower than the calibrated upshift speed to prevent insufficient vehicle power when the brake is released. Therefore, this value is usually taken as the upshift speed as the reference value. The upshift speed is determined based on the engine throttle MAP. The value of Thd2 is usually higher than the engine idle speed to prevent the clutch from disengaging accidentally at idle. The difference between Thd1 and Thd2 must ensure that there is a sufficient control buffer during the clutch disengagement process.

[0061] In some specific embodiments, the first engine speed threshold Thd1 ranges from 850 to 1050 rpm; The second engine speed threshold Thd2 ranges from 550 to 750 rpm.

[0062] By setting the first engine speed threshold Thd1 to a range of 850-1050 rpm and the second engine speed threshold Thd2 to a range of 550-750 rpm, two key speed reference points are provided for clutch disengagement control during emergency braking. These points cover the typical range of engine speed from normal operating speed to near idle speed, enabling the clutch to respond in stages as engine speed decreases. This avoids premature disengagement that could affect engine braking performance and prevents late disengagement that could lead to engine stalling, thus optimizing the control timing.

[0063] Beneficial effects of claim 6 In one specific embodiment, Thd1-Thd2 = 300 rpm.

[0064] In some specific embodiments, controlling the clutch to perform a disengagement action based on the comparison between the engine speed and a preset first engine speed threshold Thd1 and a second engine speed threshold Thd2 specifically includes: When the engine speed is higher than Thd1, the clutch is kept engaged. When the engine speed is between Thd2 and Thd1, the clutch is controlled to disengage at a preset disengagement slope; When the engine speed is below Thd2, the travel of the clutch release bearing is controlled to reach the preset critical travel, and then the real-time clutch requested torque is calculated and controlled. until the clutch is fully disengaged; Real-time clutch torque request The calculation formula is:

[0065] in, This indicates the pre-calibrated engine torque proportionality coefficient; This indicates the engine's real-time output torque; Indicates the real-time engine speed; Indicates based on real-time engine speed Determined engine speed weighting coefficient; This represents the weighting coefficient for the pre-calibrated input shaft speed descent slope. This represents the absolute value of the slope of the input shaft speed decrease. Represents the absolute value of the rate of change of engine speed; Represents the absolute value of the rate of change of engine torque; This represents the dynamic attenuation gain determined based on the absolute values ​​of the engine speed change rate and the engine torque change rate.

[0066] By controlling the clutch to perform disengagement action during emergency braking based on the comparison relationship between engine speed and Thd2 and Thd1, and calculating the real-time clutch request torque using the corresponding formula when the engine speed is lower than Thd2, dynamic parameters such as real-time engine output torque, real-time engine speed, absolute value of the input shaft speed drop slope, absolute value of the engine speed change rate, and absolute value of the engine torque change rate are integrated and adjusted through pre-calibrated weighting coefficients and dynamic attenuation gain. This allows the clutch disengagement process to match the transient changes of the power system in real time, achieving torque balance and coordination of disengagement action, reducing impact and ensuring timely disengagement.

[0067] In some specific embodiments, the critical stroke is specifically defined as the position reached by the clutch release bearing after it has shifted by a preset offset amount in the direction of increasing clutch release stroke, based on the clutch KP point.

[0068] By defining the critical stroke specifically as the position reached after the clutch release bearing travels to the clutch KP point and then shifts in the direction of increasing the clutch release stroke by a preset offset, the initial position of the clutch when torque control begins during the low-speed phase of emergency braking is clarified. This allows the clutch to enter the torque adjustment phase from near the mechanical disengagement point, avoiding the influence of inertial load in the fully engaged state and providing a suitable starting point for subsequent precise torque control, which is conducive to achieving a smooth transition from mechanical disengagement to torque control.

[0069] In some specific embodiments, the preset offset value ranges from 3% to 8% of the total separation stroke of the release bearing.

[0070] By setting the preset offset value range to 3%-8% of the total disengagement stroke of the clutch release bearing, an empirically reasonable range is provided for determining the critical stroke. This ensures that the offset is neither too small, which would leave the clutch in a near-fully engaged state and affect the torque control response, nor too large, which would cause it to enter the disengagement state too early and lose the engine braking effect. This achieves a balance between protecting the clutch and maintaining braking performance, and optimizes the setting of the control start point.

[0071] In some specific embodiments, The calculation formula is:

[0072] in, This represents the initial gain, with a value ranging from 0.8 to 1.0. This represents the attenuation factor, with a value range of 0.0001-0.0002; This represents the minimum offset, with a value ranging from 0.2 to 0.4. Bench simulation tests at different speeds are required to measure and obtain the optimal results. , , Matching relationship; The calculation formula is:

[0073] in, This represents the weight of the rate of change of rotational speed, with a value range of 0.0002-0.0005; This represents the weight of the torque change rate, with a value ranging from 0.001 to 0.003. Bench simulation tests simulating engine speed and torque are required for adjustment. and This allows for a smooth transition of the torque requested by the clutch.

[0074] In some specific embodiments, the real-time clutch requests torque. The rate of change must be satisfied, specifically: within a unit time step Internally, the real-time clutch requests torque. Change satisfy:

[0075] This indicates the preset limit for the rate of change of clutch requested torque.

[0076] By requiring that the change in real-time clutch requested torque within a unit time step does not exceed a preset limit for the rate of change of clutch requested torque, the rate of change of clutch torque control command is constrained. This avoids sudden changes in clutch actuator action or torque disturbances in the transmission system caused by jumps in torque requested value, thereby ensuring smooth torque transmission during clutch disengagement, reducing adverse effects on vehicle ride comfort, and improving control stability and ride comfort.

[0077] In some specific embodiments, The value ranges from 0.3 to 0.8; The value needs to be determined through actual vehicle testing and must meet the following conditions: The driver experienced no noticeable impact, no abnormal noises during gear shifting, and no body swaying caused by sudden torque changes during braking.

[0078] In some specific embodiments, when the braking intention is smooth braking, the engine speed meets the preset condition, which means that the engine speed is lower than the sum of the engine idle speed and the preset speed compensation value.

[0079] In some specific embodiments, the speed compensation value is 50-150 rpm.

[0080] Among them, the speed compensation value needs to ensure that the engine does not stall under load and that the engine overcomes internal friction and the basic load of accessories; the speed compensation value is a fixed value, which is determined by the engine type and displacement.

[0081] By setting the speed compensation value to a range of 50-150 rpm, an adjustable buffer zone is provided for the engine speed conditions during smooth braking. This allows the control system to prepare in advance when the engine speed is slightly higher than the rated idle speed, without being overly sensitive. This balances the need to prevent engine stalling and maintain engine braking effect, making the timing of downshifting and clutch disengagement more reasonable and flexible, adapting to different vehicle configurations and driving environments.

[0082] In some specific embodiments, the current actual vehicle speed is compared with a preset vehicle speed threshold. Based on the comparison result, it is determined whether to perform a downshift operation and control the clutch to disengage. Specifically, this includes: S301. Compare the current actual vehicle speed with the preset vehicle speed threshold; S302. If the current actual vehicle speed is higher than the preset vehicle speed threshold, then perform a downshift operation; after the downshift operation is completed, return to step S301; If the current actual vehicle speed is not higher than the preset vehicle speed threshold, the current gear will be maintained and the clutch will be fully disengaged.

[0083] By comparing the current actual vehicle speed with a preset vehicle speed threshold during smooth braking, and determining whether to perform a downshift and control clutch disengagement based on the comparison result, this method introduces vehicle speed as a key parameter for downshifting decisions. This makes it possible to enhance engine braking by downshifting at higher vehicle speeds and to maintain the gear and disengage the clutch at lower vehicle speeds. This avoids frequent downshifting at low speeds, optimizes gear selection and power management during braking, and improves driving smoothness and braking efficiency.

[0084] In some specific embodiments, the method for determining the preset vehicle speed threshold is as follows: The maximum permissible vehicle speed without drag is calculated by using engine idle speed, the highest speed ratio of the low gear of the transmission, and the rear axle ratio, and is used as the preset vehicle speed threshold.

[0085] In some specific embodiments, the preset vehicle speed threshold ranges from 8 to 15 km / h.

[0086] In some specific embodiments, in step S302, the target gear for downshifting is determined based on the engine's economic speed and the current actual vehicle speed, specifically including: Find the engine speed range covered by the lowest fuel consumption rate under the real-time output torque condition in the engine universal characteristic curve, and define the engine speed range as the economic speed range of the engine under the current operating conditions. Within the engine's economic speed range, the engine speed value closest to the real-time engine speed is selected as the target engine speed. ; Based on the current actual vehicle speed and target engine speed Calculate the target speed ratio The calculation formula is:

[0087] in, Indicates the rolling radius of the wheel; This represents a fixed calibration constant used for converting units of rotational speed and vehicle speed; Indicates the final drive ratio; Based on the gear ratio values ​​of each gear in the AMT transmission, select the gear that is closest to the target gear ratio as the target gear.

[0088] Among them, the universal characteristic curve of the engine has engine speed as the horizontal axis and engine torque as the vertical axis, superimposed with the fuel consumption rate contour line.

[0089] By determining the economical engine speed range under the current real-time output torque conditions based on the engine's universal characteristic curve, and selecting the speed value closest to the real-time engine speed as the target engine speed, the target gear ratio is calculated based on the current actual vehicle speed and the target engine speed. Finally, the gear closest to the target gear ratio is selected as the target gear. This method introduces fuel economy considerations during braking downshifting, ensuring that the engine speed after downshifting falls into the high-efficiency range. It takes into account energy utilization efficiency while assisting braking, thereby improving the overall economy of the vehicle.

[0090] The following are embodiments of the AMT transmission control system under braking conditions provided in this application. This AMT transmission control system under braking conditions belongs to the same inventive concept as the AMT transmission control methods in the above embodiments. For details not described in detail in the embodiments of the AMT transmission control system, please refer to the embodiments of the AMT transmission control methods under braking conditions described above.

[0091] like Figure 2 As shown, the AMT transmission control system under braking conditions includes: The data acquisition module is used to acquire the duration of the brake pedal being depressed, the actual vehicle speed, the actual vehicle acceleration, and the engine speed when the vehicle is in a braking and deceleration state. The braking intention determination module is used to determine the driver's braking intention based on the duration of the brake pedal being depressed and the actual acceleration of the vehicle. If the actual acceleration of the vehicle is lower than the acceleration threshold corresponding to the current duration of the brake pedal being depressed, the braking intention is determined to be emergency braking; otherwise, the braking intention is determined to be smooth braking. The emergency braking control module is used to maintain the current gear of the AMT transmission when the braking intention is emergency braking, and to control the clutch to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2, where Thd1>Thd2. The smooth braking control module is used to compare the current actual vehicle speed with a preset vehicle speed threshold when the engine speed meets the preset conditions, and to determine whether to perform a downshift operation based on the comparison result, and to control the clutch to disengage.

[0092] The AMT transmission control system in this embodiment is used to implement the AMT transmission control method under braking conditions.

[0093] This application also provides an electronic device for implementing the various embodiments of this application. Figure 3 To illustrate the hardware structure of an electronic device according to various embodiments of this application, as shown in the following diagram... Figure 3 As shown, the electronic device includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor.

[0094] Those skilled in the art will understand that the electronic device structure involved in the embodiments of this application does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0095] In embodiments of this application, electronic devices include, but are not limited to, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices may also represent various forms of mobile devices and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments of this application described and / or claimed herein.

[0096] In this application embodiment, the processor can be implemented using at least one of an Application-Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Digital Signal Processing Device (DSPD), a processor, a controller, a microcontroller, a microprocessor, or an electronic unit designed to perform the functions described herein. In some cases, such implementations can be implemented within a controller. For software implementations, implementations such as processes or functions can be implemented with separate software modules that allow the performance of at least one function or operation. The software code can be implemented by a software application (or program) written in any suitable programming language, and the software code can be stored in memory and executed by the controller.

[0097] In addition, the electronic device includes some functional modules not shown, which will not be described in detail here.

[0098] Those skilled in the art will understand that the various aspects of the electronic device provided in this application can be implemented as a system, method, or program product. Therefore, the various aspects of this application can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software aspects, collectively referred to herein as a "circuit," "module," or "system."

[0099] This application also provides a storage medium storing a program product capable of implementing an AMT transmission control method under braking conditions. In some possible implementations, various aspects of this application can also be implemented as a program product comprising program code that, when run on a terminal device, causes the terminal device to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this application.

[0100] The storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example,, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0101] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. 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 this application. Therefore, this application 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 an AMT transmission under braking conditions, characterized in that, include: S1. When the vehicle is in a braking and deceleration state, obtain the duration of the brake pedal being pressed, the actual vehicle speed, the actual vehicle acceleration, and the engine speed; S2. Determine the driver's braking intention based on the duration of brake pedal depressing and the actual vehicle acceleration; Specifically, if the actual acceleration of the vehicle is lower than the acceleration threshold corresponding to the current brake pedal depress duration, the braking intention is determined to be emergency braking; otherwise, the braking intention is determined to be smooth braking. The acceleration threshold is a pre-calibrated value, and the acceleration threshold < 0. S3. Based on the braking intention, control the gear position and clutch disengagement state of the AMT transmission until the braking ends; If the braking intention is emergency braking, the current gear of the AMT transmission is maintained, and the clutch is controlled to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2, where Thd1>Thd2. If the braking intention is smooth braking, then when the engine speed meets the preset conditions, the current actual vehicle speed is compared with the preset vehicle speed threshold. Based on the comparison result, it is determined whether to perform a downshift operation and control the clutch to disengage.

2. The AMT transmission control method as described in claim 1, characterized in that, In step S2, the acceleration threshold calibration step includes: Multiple sets of real vehicle braking tests were performed under different conditions. Each set of real vehicle braking tests included a complete braking process using a real vehicle, and the duration of brake pedal depressing and the actual vehicle acceleration during the braking process were collected as sample data for that set of real vehicle braking tests. Based on sample data showing that the driver's actual braking intention is emergency braking, the critical value of the vehicle's actual acceleration is determined for different brake pedal depress durations, and this critical value is calibrated as the acceleration threshold corresponding to that level of brake pedal depress duration.

3. The AMT transmission control method as described in claim 1, characterized in that, In step S3, controlling the clutch to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2 specifically includes: When the engine speed is higher than Thd1, the clutch is kept engaged. When the engine speed is between Thd2 and Thd1, the clutch is controlled to disengage at a preset disengagement slope; When the engine speed is below Thd2, the travel of the clutch release bearing is controlled to reach the preset critical travel, and then the real-time clutch requested torque is calculated and controlled. until the clutch is fully disengaged; Real-time clutch torque request The calculation formula is: in, This indicates the pre-calibrated engine torque proportionality coefficient; This indicates the engine's real-time output torque; Indicates the real-time engine speed; Indicates based on real-time engine speed Determined engine speed weighting coefficient; This represents the weighting coefficient for the pre-calibrated input shaft speed descent slope. This represents the absolute value of the slope of the input shaft speed decrease. Represents the absolute value of the rate of change of engine speed; Represents the absolute value of the rate of change of engine torque; This represents the dynamic attenuation gain determined based on the absolute values ​​of the engine speed change rate and the engine torque change rate.

4. The AMT transmission control method as described in claim 3, characterized in that, The critical stroke is specifically defined as the position reached after the clutch release bearing has shifted by a preset offset amount in the direction of increasing the clutch release stroke, based on the clutch KP point.

5. The AMT transmission control method as described in claim 1, characterized in that, In step S3, when the braking intention is smooth braking, the engine speed meets the preset condition, which means that the engine speed is lower than the sum of the engine idle speed and the preset speed compensation value.

6. The AMT transmission control method as described in claim 1, characterized in that, In step S3, the current actual vehicle speed is compared with a preset vehicle speed threshold. Based on the comparison result, it is determined whether to perform a downshift operation and the clutch is disengaged. Specifically, this includes: S301. Compare the current actual vehicle speed with the preset vehicle speed threshold; S302. If the current actual vehicle speed is higher than the preset vehicle speed threshold, then perform a downshift operation; after the downshift operation is completed, return to step S301; If the current actual vehicle speed is not higher than the preset vehicle speed threshold, the current gear will be maintained and the clutch will be fully disengaged.

7. The AMT transmission control method as described in claim 1, characterized in that, In step S302, the target gear for downshifting is determined based on the engine's economic speed and the current actual vehicle speed, specifically including: Find the engine speed range covered by the lowest fuel consumption rate under the real-time output torque condition in the engine universal characteristic curve, and define the engine speed range as the economic speed range of the engine under the current operating conditions. Within the engine's economic speed range, the engine speed value closest to the real-time engine speed is selected as the target engine speed. ; Based on the current actual vehicle speed and target engine speed Calculate the target speed ratio The calculation formula is: in, Indicates the rolling radius of the wheel; This represents a fixed calibration constant used for converting units of rotational speed and vehicle speed; Indicates the final drive ratio; Based on the gear ratio values ​​of each gear in the AMT transmission, select the gear that is closest to the target gear ratio as the target gear.

8. An AMT transmission control system under braking conditions, characterized in that, To implement the AMT transmission control method as described in any one of claims 1-7, comprising: The data acquisition module is used to acquire the duration of the brake pedal being depressed, the actual vehicle speed, the actual vehicle acceleration, and the engine speed when the vehicle is in a braking and deceleration state. The braking intention determination module is used to determine the driver's braking intention based on the duration of the brake pedal being depressed and the actual acceleration of the vehicle. If the actual acceleration of the vehicle is lower than the acceleration threshold corresponding to the current duration of the brake pedal being depressed, the braking intention is determined to be emergency braking; otherwise, the braking intention is determined to be smooth braking. The emergency braking control module is used to maintain the current gear of the AMT transmission when the braking intention is emergency braking, and to control the clutch to perform a disengagement action based on the comparison between the engine speed and the preset first engine speed threshold Thd1 and second engine speed threshold Thd2, where Thd1>Thd2. The smooth braking control module is used to compare the current actual vehicle speed with a preset vehicle speed threshold when the engine speed meets the preset conditions, and to determine whether to perform a downshift operation based on the comparison result, and to control the clutch to disengage.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes a computer program, it implements the steps of the AMT transmission control method as described in any one of claims 1-7.

10. A storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the AMT transmission control method as described in any one of claims 1-7.

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