A method and system for regulating the speed difference of a shift clutch of a transmission system

Abstract

The application discloses a kind of transmission system shift clutch speed difference adjusting method and system, comprising the following steps: according to the structural characteristics of vehicle transmission system, the kinematic characteristics and power flow of each gear are obtained;According to the kinematic characteristics and the output speed of power source, the initial speed difference of the clutch to be engaged in the process of gear shifting is calculated;According to the speed difference, the average temperature rise and unit sliding friction work in the process of clutch engagement are predicted;When the average temperature rise or unit sliding friction work exceeds the corresponding threshold value, the oil pressure delay instruction is triggered, and the power source speed regulation instruction is generated synchronously;According to the oil pressure delay instruction, the clutch oil pressure boost starting time is delayed;According to the power source speed regulation instruction, the power source speed is adjusted within the delay period to reduce the speed difference;After the delay ends, the clutch oil pressure boost is executed to complete the engagement.The application can effectively solve the overheating problem under low-speed crawling condition, and expand the applicable working condition range of the clutch.

Description

Technical Field

[0001] This invention belongs to the field of clutch speed difference adjustment technology, and particularly relates to a method and system for adjusting the speed difference of a transmission system shift clutch. Background Technology

[0002] As a key component of modern vehicle transmission systems, the performance of the shift clutch directly affects the vehicle's power, economy, and comfort. With the development of vehicle powertrain systems towards higher efficiency and intelligence, higher demands are being placed on clutch control technology. Clutch thermal load is a critical factor affecting system reliability and durability. During gear shifting, the speed difference between the clutch's driving and driven plates causes severe slippage, leading to a rapid increase in the temperature of the friction materials. Under high-temperature conditions, the friction elements undergo thermal warping and deformation, resulting in failure. Therefore, the root cause of clutch failure lies in the excessive thermal load caused by an excessive speed difference. Current solutions to clutch thermal load problems in the technical field mainly fall into the following categories:

[0003] The first category is passive cooling technology, which enhances heat dissipation by improving the clutch structure design. This mainly includes: optimized heat dissipation structure, such as patent CN223105086U which proposes a high-heat-dissipation diaphragm spring. By setting heat dissipation grooves in the disc, it utilizes the airflow generated during rotation to achieve efficient heat dissipation inside the clutch. While this solution improves local heat dissipation conditions, it cannot fundamentally reduce the heat load. The second category is active ventilation design: patent CN222229232U describes a tunnel boring machine clutch with anti-heat accumulation function. It uses air inlets and outlets on the outer shell, utilizing the rotation of the shell to achieve internal air circulation, while also incorporating cooling fan blades to enhance heat dissipation. This solution requires additional mechanical structures, increasing system complexity and cost.

[0004] The second category: Temperature monitoring and protection technologies, which address heat load issues by monitoring temperature in real time and taking protective measures. Emergency transmission switching: Patent CN115306833B proposes an anti-slip electronic clutch that automatically switches from friction transmission to mechanical transmission when high temperature or overload is detected, preventing slippage or damage. This is a passive protection mechanism and cannot prevent the accumulation of heat load. Heat load detection: Patent CN116296359B proposes a quantitative heat load durability testing device for flywheel and clutch systems, focusing on the quantitative detection of heat load and providing data support for thermal management, but lacking active control methods.

[0005] The third category is simulation prediction technology, which predicts heat load generation by establishing models. Patent CN118780165A proposes a simulation calculation method for the slippage work of a tractor clutch. It establishes a simulation model by obtaining initial slippage parameters and calculates the total heat generated by the clutch under specific conditions. This approach helps optimize design, but it cannot control the heat load in real time.

[0006] A comprehensive analysis of existing technologies reveals the following limitations in reducing clutch thermal load: Control strategies are simplistic, with most solutions focusing only on heat dissipation or protection, lacking proactive intervention in the heat load generation process. For example, heat dissipation technology cannot reduce slippage work, and protection technology can only take action after the temperature exceeds the limit. Furthermore, there is a lack of system coordination; existing technologies often address the problem from a single perspective, failing to establish a quantitative relationship between speed difference, slippage time, and thermal load, and lacking multi-parameter coordinated control mechanisms. Summary of the Invention

[0007] This invention proposes a method and system for adjusting the speed difference of a transmission system's shift clutch, in order to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides a method for adjusting the speed difference of a transmission system shift clutch, comprising the following steps:

[0009] Based on the structural characteristics of the vehicle's transmission system, obtain the kinematic characteristics and power flow of each gear;

[0010] Based on the kinematic characteristics and the output speed of the power source, calculate the initial speed difference of the clutch to be engaged during the gear shift process;

[0011] Based on the aforementioned speed difference, predict the average temperature rise and unit slip friction work during clutch engagement;

[0012] When the average temperature rise or unit sliding friction work exceeds the corresponding threshold, an oil pressure delay command is triggered, and a power source speed adjustment command is generated simultaneously.

[0013] According to the oil pressure delay command, the start time of clutch oil pressure boosting is delayed;

[0014] According to the power source speed adjustment command, the power source speed is adjusted during the delay period to reduce the speed difference;

[0015] After the delay ends, the clutch oil pressure is increased to complete engagement.

[0016] Optionally, acquiring the kinematic characteristics and power flow of each gear position includes:

[0017] Based on the gear ratio of the transmission system, the characteristic parameters of the planetary gear set, and the clutch arrangement scheme, a kinematic matrix characterizing the speed relationship of each component is established.

[0018] Based on the kinematic matrix and clutch arrangement scheme, determine the engagement clutch and its input / output components for transmitting power in each gear.

[0019] Starting from the output shaft of the power source and ending at the output shaft of the transmission system, determine the power flow for each gear.

[0020] Optionally, the calculation of the initial speed difference of the clutch to be engaged during the gear shift includes:

[0021] The clutch to be engaged is determined based on the current gear and the target gear;

[0022] Based on the kinematic characteristics, determine the speed relationship between the driving and driven components of the clutch to be engaged in the current gear.

[0023] Based on the relationship between the output speed of the power source and the speed, the initial speed difference of the clutch to be engaged at the initial moment of gear shift is calculated.

[0024] Optional, the predicted average temperature rise and unit slip work include:

[0025] Calculate the friction work based on the speed difference, load torque, and estimated friction time.

[0026] The average temperature rise is calculated based on the sliding friction work, friction plate mass, specific heat capacity, number of friction pairs, and contact area.

[0027] The unit friction work is calculated based on the friction work and the contact area of ​​the friction pair.

[0028] Optionally, triggering hydraulic pressure delay commands include:

[0029] Calculate the ratio α between the predicted average temperature rise and the set limit temperature rise;

[0030] Calculate the ratio β of the predicted unit friction work to the set limit unit friction work;

[0031] When α≥1 or β≥1, the oil pressure delay command is triggered.

[0032] Optionally, the delayed clutch oil pressure boosting start time includes:

[0033] When the hydraulic pressure delay control command is triggered, the timer is started and the dynamic delay time is calculated;

[0034] During the dynamic delay time, the duty cycle of the control proportional valve is zero to delay the rise of clutch oil pressure;

[0035] After the dynamic delay time ends, the control proportional valve adjusts the oil pressure according to a preset nonlinear pressure rise curve to complete the engagement of the clutch to be engaged.

[0036] Optionally, adjusting the power source speed during the delay period includes:

[0037] The target speed of the power source is determined based on the initial speed difference and the shift type.

[0038] The power source controller sends a speed adjustment command via the CAN bus to adjust the actual speed of the power source to the target speed.

[0039] The present invention also provides a transmission system shift clutch speed difference adjustment system, comprising:

[0040] The speed difference detection module is used to calculate the initial speed difference of the clutch to be engaged during gear shifting based on the structural characteristics of the transmission system, the output speed of the power source, the gear signal, and the load torque, and to predict its thermal load parameters.

[0041] The hydraulic pressure delay control module is used to generate and execute hydraulic pressure delay control commands based on the comparison results between the heat load parameters and preset thresholds.

[0042] The power source adjustment module is used to generate and execute a power source speed adjustment command based on the comparison result between the heat load parameters and the preset threshold.

[0043] Compared with the prior art, the present invention has the following advantages and technical effects:

[0044] This invention employs an innovative three-dimensional coordinated control strategy of "time-speed-oil pressure" to significantly reduce the clutch speed difference during gear shifting, thereby greatly reducing frictional heat load and significantly extending the service life of friction materials. Furthermore, this invention creatively combines the time dimension of oil pressure control with the spatial dimension of engine speed regulation, achieving a perfect balance between shift quality and thermal management. By precisely controlling the oil pressure delay time window, sufficient time margin is provided for engine speed regulation; while precise tracking of engine speed creates conditions for a smooth rise in oil pressure. This two-way coordinated mechanism reduces shift shock. Particularly for dual-clutch transmissions, this invention effectively solves the overheating problem under low-speed creep conditions, expanding the applicable operating conditions of the clutch. Attached Figure Description

[0045] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0046] Figure 1 This is a schematic diagram of a method according to an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the speed difference detection module according to an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the oil pressure delay control module according to an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the power source adjustment module according to an embodiment of the present invention;

[0050] Figure 5 This is a simplified rotational diagram of the transmission device according to an embodiment of the present invention;

[0051] Figure 6 This is a diagram showing the average temperature of the shift clutch in an embodiment of the present invention.

[0052] Figure 7 This is a diagram illustrating the engine speed regulation effect in an embodiment of the present invention. Detailed Implementation

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0055] Example 1

[0056] like Figure 1 As shown, this embodiment provides a method for adjusting the speed difference of a transmission system's shift clutch, including the following steps:

[0057] Based on the structural characteristics of the vehicle's transmission system, obtain the kinematic characteristics and power flow of each gear;

[0058] Based on the kinematic characteristics and the output speed of the power source, calculate the initial speed difference of the clutch to be engaged during the gear shift process;

[0059] Based on the aforementioned speed difference, predict the average temperature rise and unit slip friction work during clutch engagement;

[0060] When the average temperature rise or unit sliding friction work exceeds the corresponding threshold, an oil pressure delay command is triggered, and a power source speed adjustment command is generated simultaneously.

[0061] According to the oil pressure delay command, the start time of clutch oil pressure boosting is delayed;

[0062] According to the power source speed adjustment command, the power source speed is adjusted during the delay period to reduce the speed difference;

[0063] After the delay ends, the clutch oil pressure is increased to complete engagement.

[0064] Specifically, the following steps are included:

[0065] 1. Determine the vehicle's power source type (engine, motor, engine and motor). Based on the structural characteristics of the transmission system, obtain the kinematic characteristics of each gear and the power flow of each gear, thereby obtaining the working state of the shift clutch under different shifting conditions. The structural characteristics include the gear ratios of each stage of gears or planetary gears, characteristic parameters of each planetary gear set, the number of gear pairs, the number of shift clutches, and their arrangement. The kinematic characteristics of each gear are characterized by a kinematic matrix composed of the speed relationships between the components of different gears in the transmission system. Based on the kinematic characteristics and the clutch arrangement, determine the shift clutches and their input / output components that actually transmit power in each gear. Based on this, with the power source output shaft as the starting point and the transmission system's main shaft (output shaft) as the ending point, the power flow of each gear can be determined.

[0066] 2. The power source output speed n is collected by the speed sensor. e Based on the structural characteristics from the previous step, the kinematic characteristics of each gear in the transmission system are determined, and the speed difference Δn of the shift clutch at the initial moment of shifting under different shifting conditions is calculated. The specific method is as follows:

[0067] (1) Determine the kinematic characteristics of each gear. Based on the kinematic relationship of the gear pair and the planetary gear mechanism, establish the basic component matrix, clutch component matrix and planetary gear component matrix that can characterize the essential characteristics of the structure; determine the number of degrees of freedom N when the transmission device is not engaged based on the total number of components and the number of gear pairs or planetary gear sets; set independent components with the same number of degrees of freedom and establish the speed vector of independent components. The speed relationship of an independent component can be determined for each clutch engaged, and the number of degrees of freedom of the transmission system is reduced by one. Therefore, the speed of the independent component can be linearly expressed by the speed of the remaining independent components; when the number of engaged clutches is N-1, the system has 1 degree of freedom. At this time, it is only necessary to determine the speed of one component to obtain the speed of the remaining components; combine the speed relationships of each component corresponding to each gear into a kinematic matrix to characterize the kinematic characteristics of each component.

[0068] (2) Determine the speed relationship between the clutch to be engaged in the rear gear and the corresponding active and passive components under the shifting condition. After determining the power flow of each gear, the engagement clutch corresponding to each gear can be determined; the shifting clutch corresponding to the rear gear in the shifting condition is different from the forward gear, which is the clutch to be engaged in the shifting condition; determine the active and passive components of the shifting clutch according to the structural characteristics of the transmission device, and determine the speed relationship between the active and passive components of the shifting clutch in the forward gear according to the kinematic characteristics of each gear.

[0069] (3) Calculate the initial speed difference Δn of the clutch during gear shifting. The speed difference Δn is calculated based on the power source output speed n collected by the speed sensor. e Based on the kinematic characteristics of each gear, n e The absolute value of the speed difference between the driving and driven components of the clutch to be engaged in the previous gear shift is calculated, which is the speed difference Δn of the clutch at the initial moment of the shift.

[0070] 3. Calculate the clutch speed difference The sliding friction work;

[0071] Between the driving and driven ends of the clutch, the power P lost through friction is... fc for:

[0072] (1)

[0073] In the formula, T fc It is the passive resistance torque of the shift clutch, which can be calculated from the load torque measured by the torque sensor installed on the output shaft.

[0074] The slip friction work of the clutch can be obtained by the following formula:

[0075] (2)

[0076] In the formula, t is the clutch slippage time. Here, the clutch shifting time is estimated based on the specific vehicle model and operating conditions, and is an empirical value.

[0077] 4. The predicted average temperature rise and unit slip friction work after clutch engagement can be expressed as:

[0078] (3)

[0079] (4)

[0080] In the formula, T0 is the average temperature at the initial moment of clutch shifting, which can be taken as 80 to 100℃ for hydraulic mechanical integrated transmission devices; m is the average mass of a single friction plate; c is the specific heat capacity of the friction element; Z is the number of friction pairs; and A is the contact area of ​​the friction pairs.

[0081] 5. The hydraulic pressure delay command includes two signals: the average temperature rise signal and the unit slip friction work signal. These two signals are determined by the speed difference of the shift clutch. The calculations are as follows: Data such as the power source output speed, gear characteristics, and load torque are collected using speed sensors, gear position sensors, and torque sensors. These data are then combined with the preset average temperature rise formula and unit slip friction work formula from step 4 to calculate the predicted value in real time. Two signal limit values ​​are set as shown in Table 1.

[0082] Table 1

[0083]

[0084] α and β are the threshold values ​​of the oil pressure delay command signal. α is the ratio of the predicted average temperature rise signal Ta to the limit value Tm of the average temperature rise signal, and β is the ratio of the predicted unit sliding friction work signal Ja to the limit value Jm of the unit sliding friction work. The calculation formulas are as follows:

[0085] (5)

[0086] The threshold comparison is performed by the TCU. As long as any signal exceeds the threshold (α≥1 or β≥1), the oil pressure delay command is triggered.

[0087] 5. Initialize the hydraulic pressure delay control program. When the system is powered on, the TCU loads preset basic data such as clutch type parameters and hydraulic system characteristics to complete a self-test. The PWM frequency and initial duty cycle of the proportional valve are determined through calibration experiments and stored in the TCU's non-volatile memory.

[0088] The preset nonlinear pressure rise curve parameters include the initial pressure, slope change point, and target pressure value: ① Initial pressure (P0): set according to the holding pressure when the clutch is fully disengaged, usually 0.2-0.5MPa; ② Slope change point: based on the clutch piston stroke-pressure characteristic curve, the key inflection point is calibrated through bench testing; ③ Target pressure value: determined by back-calculation of the clutch's rated transmission torque, combined with the safety factor.

[0089] 6. When the TCU issues a shift command but the delay condition is not triggered:

[0090] a. The proportional valve directly applies a preset nonlinear pressure rise curve;

[0091] b. The high-response solenoid valve precisely adjusts the oil flow rate according to the curve requirements;

[0092] c. Hydraulic oil pushes the clutch piston to complete the engagement process.

[0093] 7. When the TCU issues a shift command and triggers the delay condition:

[0094] a. After the hydraulic pressure delay command is triggered (α≥1 or β≥1), the TCU's timer module starts;

[0095] b. Calculate the dynamic delay time: t d =k×max(α,β), where K is the delay coefficient, which is determined based on the engine speed regulation capability, and it is recommended to take k=0.2s.

[0096] c. The PWM signal is generated by the TCU's hardware timer, with a fixed frequency of 2kHz (matching the proportional valve's response characteristics). During the delay period, the duty cycle is forced to zero (the valve core remains at zero position).

[0097] d. After the delay ends, the TCU switches to the preset PWM duty cycle corresponding to the boost curve. The duty cycle is dynamically adjusted according to the slope of the pressure curve (updated every 10ms). Frequency stability is guaranteed by the TCU's clock synchronization mechanism, with an error of less than ±0.1%.

[0098] 8. Execution of power source speed adjustment commands: Torque commands are transmitted in real time to the engine ECU or motor controller via the CAN bus. Upon receiving a downshift command, the theoretical speed increment is calculated based on the target gear ratio and the current vehicle speed. A feedforward control strategy is adopted to increase the throttle opening (for gasoline vehicles) or motor torque (for electric vehicles) 10ms in advance. Upon receiving an upshift command, engine braking (fuel injector shutdown in gasoline vehicles) or motor reverse drag (current cut off in electric vehicles) is triggered to achieve rapid deceleration. For hybrid vehicles, the motor is given priority for rapid response, while the engine acts as an auxiliary unit for fine-tuning.

[0099] 9. Gear position characteristic judgment and speed adjustment;

[0100] The gear position sensor determines whether to upshift or downshift.

[0101] ① Downshifting operation:

[0102] Based on the speed difference of the shift clutch at the initial moment of shifting. The power source speed increment is determined as follows:

[0103] (6)

[0104] Through feedforward compensation at t d The power source output is adjusted within a certain time frame, and the speed increase is matched by pre-boosting to avoid jerking caused by the speed increase, so that the power source speed increases linearly to the desired level. If the speed exceeds the maximum speed of the power source, it will increase to the maximum speed.

[0105] ② Upshifting operation:

[0106] Based on the speed difference of the shift clutch at the initial moment of shifting. The amount of speed reduction of the power source was determined to be .

[0107] In gasoline-powered vehicles, engine braking is achieved through delayed ignition, while electric vehicles utilize engine braking. In hybrid vehicles, the electric motor handles 80% to 100% of the braking torque, with the engine only providing inertial compensation. Real-time performance is ensured through a CAN bus arbitration mechanism.

[0108] By using closed-loop PID control to adjust the fuel injection quantity / current, the power source is kept at the target speed. .

[0109] 10. Recovery strategy after power source adjustment;

[0110] Speed ​​synchronization: When the difference between the actual speed of the power source and the theoretical speed of the target gear is less than the threshold (±30 rpm), the forced adjustment mode is exited.

[0111] Smooth power transition: Gradually restore fuel / electric current supply (gasoline vehicles) or motor torque (electric vehicles) to avoid sudden output changes.

[0112] Hybrid power coordination: The torque of the electric motor and the engine is redistributed according to a preset ratio to ensure smoothness.

[0113] 11. Power source safety mechanism;

[0114] Speed ​​change rate limit: All commands are subject to dynamic constraints to ensure that the speed change rate is ≤2000rpm / s to prevent mechanical shock.

[0115] Hardware protection: The ECU / controller monitors parameters such as the power source's speed and temperature in real time, triggering a degradation mode (such as limiting torque and speed output) when limits are exceeded. It also monitors the battery's SOC (for hybrid systems) in real time, disabling motor reverse drag when the SOC falls below 15%.

[0116] It should be noted that the oil delay adjustment command and the power source speed adjustment command can be used individually or in combination.

[0117] This embodiment also provides a shift clutch shift speed difference adjustment system, including a speed difference detection module, an oil pressure delay control module, and a power source adjustment module.

[0118] Speed ​​difference detection module (e.g.) Figure 2 As shown in the diagram, it consists of a speed sensor, a gear position sensor, a torque sensor, and a clutch speed difference solver. The gear position sensor outputs a transmission system shift signal, clearly indicating whether the transmission system is upshifting or downshifting, and transmits the data to the clutch speed difference solver. The speed sensor is installed on the power source output side, collecting the power source output speed and transmitting the data to the clutch speed difference solver. The torque sensor is installed at the transmission system output end, measuring the load torque characteristics of the output shaft. After receiving the above signals, the clutch speed difference solver calculates the speed difference between the active and passive ends of the shift clutch based on the power transmission link under that shift condition. Based on this, the average temperature rise and unit slip friction work of the shift clutch are predicted to determine whether they exceed the preset threshold. If so, the oil pressure delay control module and power source adjustment module are triggered.

[0119] Hydraulic pressure delay control module (such as) Figure 3 (As shown): If the hydraulic delay control module is not triggered, the proportional valve, upon receiving the TCU shift command, directly executes the preset nonlinear pressure increase curve. It precisely controls the hydraulic oil flow through the high-response solenoid valve, pushing the clutch piston to engage. When the speed difference detection module triggers the delay condition, the delay mode is activated. The proportional valve's energizing time is delayed via a PWM signal, the delay time determined by the actual shift speed difference. After the delay ends, the clutch oil filling process continues. After the oil filling command is completed, the PWM delay command is eliminated.

[0120] Power source adjustment module (such as) Figure 4 (As shown): If the power source adjustment is not triggered, the original shifting strategy continues; if the power source adjustment is not triggered, based on the speed difference detection result, a speed adjustment command is sent to the engine ECU or motor controller via the CAN bus: when downshifting, feedforward control is used, calculating the theoretical speed increment based on the target gear ratio and the current vehicle speed, and increasing the throttle opening or motor torque 10ms in advance; when upshifting, engine braking or motor reverse drag is used to achieve rapid deceleration by shutting off the fuel injectors / cutting off the current. For hybrid vehicles, the fast response of the electric motor is given priority, with the engine serving as an auxiliary adjustment unit. All commands are subject to safety limits to ensure that the power source speed change rate does not exceed 2000 rpm / s.

[0121] The following experiments were also conducted in this embodiment:

[0122] Figure 5 The diagram shows a vehicle powertrain with an engine as its power source. This system does not include a planetary gear set unit except for the converging planetary gear set. Therefore, its structural features mainly include the number of gear pairs, the gear ratios of each stage, the number of shift clutches, and their arrangement. There are 12 gear pairs and 5 clutches. In the diagram, component 1 is the hydraulic torque converter; components 2, 3, 4, 5, and 6 are shift clutches CL, CR, CH, C2, and C1, respectively; Z1 is the input shaft, transmitting engine power to the transmission mechanism; Z2 is the intermediate shaft, diverting the power from input shaft Z1 to different gear sets; and Z3 is the output shaft, transmitting the output power of the transmission to the converging planetary gear set to drive the two drive wheels. Based on the structural features, the total number of components in this transmission is 17, and the number of degrees of freedom without clutch engagement is 3. Therefore, each gear is engaged by two shift clutches. The engagement clutches for each gear are determined by the structural features of this system, as shown in Table 2.

[0123] Table 2

[0124]

[0125] The power source output speed n is collected by the speed sensor. eBased on this, the speed difference of the shift clutch at the initial moment of shifting is calculated under different shifting conditions. :

[0126] (1) Determine the kinematic characteristics of each gear. As can be seen from the above analysis, the total number of degrees of freedom is 3 when the clutch is not engaged. Based on the kinematic relationship of the gear pair, establish the basic component matrix and clutch matrix that can characterize the structural characteristics. Each gear is based on the output speed n of the power source. e Using 1 as the baseline, the rotational speed of each component and n at each gear can be obtained. e The rotational speed relationship between components, i.e., the kinematic characteristics of each component.

[0127] (2) Determine the speed relationship between the clutch to be engaged in the rear gear and the corresponding components at the driving and driven ends during the gear shifting process. Taking shifting from 1st to 2nd gear as an example, the clutches engaged in 1st gear are C1 and CL, and the clutches engaged in 2nd gear are C1 and CH. Therefore, the clutch to be engaged in the rear gear (2nd gear) is CH, which is different from the clutch engaged in the front gear (1st gear). At the same time, when the gear is 1, according to the kinematic characteristics, the speeds of the driving and driven ends of the clutch CH are 1.065 rpm. e and 0.607n e .

[0128] (3) Calculate the initial speed difference Δn of the clutch during gear shifting. The initial gear shift time is determined using the kinematic relationship of the first gear. Therefore, the initial time of shifting from first to second gear can be calculated, and the speed difference Δn between the driving and driven components of the gear shifting clutch CH is 0.4580n. e Similarly, the initial speed difference of the shift clutch under each shifting condition can be obtained as shown in Table 3.

[0129] Table 3

[0130]

[0131] Calculate the clutch speed difference The sliding friction work Predict the average temperature rise and unit slip work after the clutch engagement is completed. Figure 6 This represents the average temperature rise of the shift clutch.

[0132] It can be observed that as the clutch speed difference increases, the average temperature exceeds 175℃, triggering the oil pressure delay command. The dynamic delay time, t, is calculated. d =0.14s. The energizing time of the proportional valve is delayed by t using a PWM signal. d During this period, the valve core remains in the zero position; after the delay time ends, the proportional valve is reactivated and continues to fill oil according to the pressure rise curve.

[0133] Execute the power source speed adjustment command: Upon receiving an upshift command, engine braking is triggered to achieve rapid deceleration. This is based on the speed difference between the shift clutches at the initial moment of shifting. The amount of speed reduction of the power source was determined to be .like Figure 7 As shown, when shifting from 2nd to 3rd gear, the engine speed drops from 2027 rpm to approximately 1600 rpm within 1.4 seconds.

[0134] The present invention proposes a method and system for adjusting the speed difference of a transmission system shift clutch, which has the following significant advantages compared with the prior art:

[0135] In terms of technical effectiveness, this invention, through an innovative three-dimensional coordinated control strategy of "time-speed-oil pressure", can significantly reduce the clutch speed difference during gear shifting, thereby greatly reducing the generation of frictional heat load and significantly extending the service life of friction materials.

[0136] In terms of system performance, this invention creatively combines the time dimension of hydraulic pressure control with the spatial dimension of engine speed regulation, achieving a perfect balance between shift quality and thermal management. By precisely controlling the hydraulic pressure delay time window, sufficient time margin is provided for engine speed regulation; while the precise tracking of engine speed creates conditions for a smooth rise in hydraulic pressure. This two-way collaborative mechanism reduces shift shock. Especially for dual-clutch transmissions, this invention can effectively solve the overheating problem under low-speed creep conditions, expanding the applicable operating conditions of the clutch.

[0137] In terms of implementation cost, this invention is mainly based on software algorithm innovation, requiring no additional expensive hardware devices, only optimization of the signal utilization and control strategy of existing sensors. Compared with solutions that require additional cooling systems, this invention is more economical and has greater potential for widespread adoption.

[0138] In terms of compatibility, this invention can be flexibly applied to various types of automatic transmissions, including traditional hydraulic torque converters (AT), dual-clutch transmissions (DCT), and automatic-manual transmissions (AMT), requiring only adjustments to the control parameters based on specific transmission characteristics. The system possesses excellent fault adaptability; when speed regulation is limited, it can automatically switch to pure hydraulic control mode to ensure basic shifting functionality. Furthermore, the framework of this invention can be extended to torque coordination control in hybrid power systems, demonstrating broad application prospects.

[0139] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for adjusting the speed difference of a shift clutch in a transmission system, characterized in that, Includes the following steps: Based on the structural characteristics of the vehicle's transmission system, obtain the kinematic characteristics and power flow of each gear; The acquisition of the kinematic characteristics and power flow of each gear includes: Based on the gear ratio of the transmission system, the characteristic parameters of the planetary gear set, and the clutch arrangement scheme, a kinematic matrix characterizing the speed relationship of each component is established. Based on the kinematic matrix and clutch arrangement scheme, determine the engagement clutch and its input / output components for transmitting power in each gear. Starting from the output shaft of the power source and ending at the output shaft of the transmission system, determine the power flow of each gear. Based on the kinematic characteristics and the output speed of the power source, calculate the initial speed difference of the clutch to be engaged during the gear shift process; Based on the aforementioned speed difference, predict the average temperature rise and unit slip friction work during clutch engagement; When the average temperature rise or unit sliding friction work exceeds the corresponding threshold, an oil pressure delay command is triggered, and a power source speed adjustment command is generated simultaneously. According to the oil pressure delay command, the start time of clutch oil pressure boosting is delayed; According to the power source speed adjustment command, the power source speed is adjusted during the delay period to reduce the speed difference; After the delay ends, the clutch oil pressure is increased to complete engagement.

2. The method according to claim 1, characterized in that, The calculation of the initial speed difference of the clutch to be engaged during the gear shift process includes: The clutch to be engaged is determined based on the current gear and the target gear; Based on the kinematic characteristics, determine the speed relationship between the driving and driven components of the clutch to be engaged in the current gear. Based on the relationship between the output speed of the power source and the speed, the initial speed difference of the clutch to be engaged at the initial moment of gear shift is calculated.

3. The method according to claim 1, characterized in that, The predicted average temperature rise and unit slip work include: Calculate the friction work based on the speed difference, load torque, and estimated friction time. The average temperature rise is calculated based on the sliding friction work, friction plate mass, specific heat capacity, number of friction pairs, and contact area. The unit friction work is calculated based on the friction work and the contact area of ​​the friction pair.

4. The method according to claim 1, characterized in that, The hydraulic pressure delay command includes: Calculate the ratio α between the predicted average temperature rise and the set limit temperature rise; Calculate the ratio β of the predicted unit friction work to the set limit unit friction work; When α≥1 or β≥1, the oil pressure delay command is triggered.

5. The method according to claim 1, characterized in that, The delayed clutch oil pressure boosting start time includes: When the hydraulic pressure delay control command is triggered, the timer is started and the dynamic delay time is calculated; During the dynamic delay time, the duty cycle of the control proportional valve is zero to delay the rise of clutch oil pressure; After the dynamic delay time ends, the control proportional valve adjusts the oil pressure according to a preset nonlinear pressure rise curve to complete the engagement of the clutch to be engaged.

6. The method according to claim 1, characterized in that, The adjustment of the power source speed during the delay period includes: The target speed of the power source is determined based on the initial speed difference and the shift type. The power source controller sends a speed adjustment command via the CAN bus to adjust the actual speed of the power source to the target speed.

7. A transmission system shift clutch speed difference adjustment system, used to implement the method as described in any one of claims 1-6, characterized in that, include: The speed difference detection module is used to calculate the initial speed difference of the clutch to be engaged during gear shifting based on the structural characteristics of the transmission system, the output speed of the power source, the gear signal, and the load torque, and to predict its thermal load parameters. The hydraulic pressure delay control module is used to generate and execute hydraulic pressure delay control commands based on the comparison results between the heat load parameters and preset thresholds. The power source adjustment module is used to generate and execute a power source speed adjustment command based on the comparison result between the heat load parameters and the preset threshold.

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