Control method of wet clutch, vehicle, and storage medium

Abstract

The application provides a control method of a wet clutch, a vehicle and a storage medium, and belongs to the technical field of clutch control. The method comprises the following steps: collecting characteristic data of the wet clutch, extracting target pressure and actual pressure at the current moment from the characteristic data; calculating required pressure at the current moment based on the target pressure and the actual pressure, and calculating a required pressure change rate according to the required pressure; determining predicted virtual pressure of the wet clutch at the current moment according to the required pressure and the required pressure change rate, and determining target electric control required current of an electric control actuator in the wet clutch at the current moment based on the predicted virtual pressure and the required pressure, so as to control the working of the wet clutch by using the target electric control required current. The method can fully consider the hydraulic timing dynamic characteristics, accelerate the oil pressure response speed, enhance the control stability and robustness, eliminate the problems of oil pressure overshoot and response lag, and greatly improve the vehicle driving comfort.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more specifically, to a control method, vehicle, and storage medium for a wet clutch in the field of clutch control. Background Technology

[0002] In related technologies, the desired clutch torque and actual oil pressure can be collected in real time, and the desired oil pressure, estimated oil pressure, and limiting oil pressure can be calculated step by step. After superimposing the requested oil pressure, the solenoid valve control current is output to shorten the hydraulic response time. Alternatively, the clutch oil pressure and transmission oil temperature can be collected and the oil pressure change rate can be calculated. After the correction conditions are met, the solenoid valve correction current can be calculated by combining the pre-calibrated clutch pressure data. The output can be adjusted based on the correction current, and the oil pressure control accuracy can be improved by combining the inherent calibration data of the clutch.

[0003] However, in related technologies, only instantaneous operating condition parameters are used to compensate for oil pressure and current. The inertial hysteresis of the system can easily cause oil pressure overshoot and response lag. Furthermore, the compensation amount is not combined with the overall vehicle operating conditions and there is no oil pressure prediction capability. It cannot adapt to multiple operating conditions and differences in solenoid valve characteristics. The stability, robustness and consistency of oil pressure control are poor and urgently need improvement. Summary of the Invention

[0004] This application provides a control method for a wet clutch, a vehicle, and a storage medium. This method can fully take into account the dynamic characteristics of hydraulic timing, while accelerating the oil pressure response speed and enhancing control stability and robustness, eliminating oil pressure overshoot and response lag problems, and significantly improving the overall vehicle driving comfort.

[0005] In a first aspect, a control method for a vehicle wet clutch is provided. The method includes: collecting feature data of the wet clutch at multiple moments; extracting a first target pressure and a first actual pressure of the wet clutch at the current moment from the feature data; calculating a first demand pressure of the wet clutch at the current moment based on the first target pressure and the first actual pressure; calculating a demand pressure change rate of the wet clutch at the current moment based on the first demand pressure; determining a first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate; and determining a target electronic control demand current of the electronically controlled actuator in the wet clutch at the current moment based on the first predicted virtual pressure and the first demand pressure, so as to control the operation of the wet clutch using the target electronic control demand current.

[0006] The vehicle wet clutch control method of this application embodiment can extract the target pressure and actual pressure at the current moment from the characteristic data of the wet clutch at multiple moments, thereby determining the demand pressure at the current moment, and calculating the corresponding demand pressure change rate based on the demand pressure, thereby obtaining the first predicted virtual pressure of the wet clutch at the current moment, and then determining the target electronic control demand current of the electronic control actuator at the current moment to realize the control operation of the wet clutch. It can fully take into account the dynamic characteristics of hydraulic timing, enhance control stability and robustness while accelerating the oil pressure response speed, eliminate oil pressure overshoot and response lag problems, and significantly improve the overall vehicle driving comfort.

[0007] In conjunction with the first aspect, in some possible implementations, calculating the first demand pressure of the wet clutch at the current moment based on the first target pressure and the first actual pressure includes: obtaining the first electronically controlled demand pressure of the electronically controlled actuator at the previous moment, and extracting the second target pressure and the second actual pressure of the wet clutch at the previous moment from the feature data; calculating the pressure feedforward value of the first demand pressure based on the first target pressure and the second target pressure; calculating the first pressure error value of the wet clutch at the current moment based on the first target pressure and the first actual pressure; and calculating the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value.

[0008] Based on the above technical solution, the electrical control demand pressure of the electronically controlled actuator at the previous moment can be retrieved, and the target oil pressure and actual oil pressure of the wet clutch at the previous moment can be extracted from the feature data. Then, the pressure feedforward value can be calculated based on the difference between the target pressure at the current moment and the target pressure at the previous moment, and the pressure error value at the current moment can be calculated based on the target pressure and actual pressure at the current moment. Thus, the demand pressure at the current moment can be obtained by solving the electrical control demand pressure, pressure feedforward value and pressure error value at the previous moment. By introducing time-series historical control parameters and operating state parameters to construct a feedforward superimposed feedback demand oil pressure calculation mechanism, the inherent hysteresis and inertia characteristics of the wet clutch electromechanical-hydraulic strong coupling system can be specifically compensated, effectively reducing the deviation in the dynamic pressure adjustment process and simultaneously improving the pressure response speed and control accuracy of the wet clutch.

[0009] In conjunction with the first aspect and the above implementation methods, in some possible implementation methods, calculating the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value includes: determining, based on the first pressure error value, a first proportional gain value, an integral gain value, and a first differential gain value required for calculating the first demand pressure at the current moment; determining, based on the second pressure error value of the wet clutch at the previous moment, a second proportional gain value and a second differential gain value required for calculating the first demand pressure at the previous moment; and calculating the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, the first pressure error value, the first proportional gain value, the integral gain value, the first differential gain value, the second proportional gain value, and the second differential gain value.

[0010] Based on the above technical solution, the corresponding proportional, integral, and derivative gains can be matched according to the pressure error value at the current moment. At the same time, the historical proportional and derivative gains can be obtained by combining the historical pressure error value at the previous moment. The current demand pressure can be solved by integrating the electronic control demand pressure, pressure feedforward value, proportional gain, integral gain, derivative gain, historical proportional gain, and historical derivative gain. By distinguishing between the current and historical error segments and configuring differentiated PID (Proportional Integral Derivative) gains, variable parameter composite PID control can be achieved. This can adapt to the hysteresis inertia characteristics of the dynamic changes in the wet clutch electro-hydraulic coupling system, effectively reduce the dynamic adjustment deviation of oil pressure, suppress pressure overshoot and response lag, and significantly improve the real-time performance, stability, and robustness of oil pressure control.

[0011] In conjunction with the first aspect and the above implementation methods, in some possible implementation methods, determining the first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate includes: determining the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure; determining the pressure delay coefficient of the wet clutch at the current moment based on the demand pressure change rate, and obtaining the pressure delay correction coefficient of the wet clutch at the current moment; and determining the first predicted virtual pressure based on the first demand pressure, the second predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient.

[0012] Based on the above technical solution, the corresponding historical predicted virtual pressure can be obtained from the actual pressure at the previous moment. The pressure delay coefficient can be solved by combining the current demand pressure change rate and matching the pressure delay correction coefficient. Then, the predicted virtual oil pressure at the current moment can be calculated based on the current demand pressure, the historical predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient. By introducing the time-series virtual pressure and the layered delay correction mechanism, the inherent lag characteristics of the hydraulic transmission of the wet clutch can be accurately compensated, the oil pressure prediction deviation can be reduced, and a reliable pressure reference can be provided for the subsequent precise control of the solenoid valve current, thereby improving the overall pressure control stability and following performance.

[0013] In combination with the first aspect and the above implementation methods, in some possible implementation methods, before determining the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure, the method further includes: obtaining the oil filling status identification information of the wet clutch; and when the oil filling status identification information meets the preset oil filling conditions, determining the second predicted virtual pressure based on the oil filling status identification information and the second actual pressure.

[0014] Based on the above technical solution, before determining the historical predicted virtual pressure at the previous moment, the oil filling status identification information of the wet clutch can be collected first. If the oil filling status identification information meets the preset oil filling conditions, the second predicted virtual pressure can be calculated based on the oil filling status identification information and the actual pressure at the previous moment. This distinguishes the virtual pressure benchmark constructed differently between the oil filling and non-oil filling stages of the clutch, avoids the interference of oil pressure fluctuations during the oil filling stage on the prediction accuracy, and makes the virtual pressure result fit the actual hydraulic oil filling dynamic process of the clutch, ensuring the accuracy of subsequent pressure delay correction and current control.

[0015] In combination with the first aspect and the above implementation methods, in some possible implementation methods, determining the target electronic control demand current of the electronically controlled actuator in the wet clutch at the current moment based on the first predicted virtual pressure and the first demand pressure includes: extracting the current transmission oil temperature of the wet clutch from the feature data; calculating the pressure difference between the first predicted virtual pressure and the first target pressure; calculating a pressure compensation factor based on the pressure difference and the current transmission oil temperature; and calculating the target electronic control demand current based on the pressure difference, the pressure compensation factor, and the first demand pressure.

[0016] Based on the above technical solution, the current transmission oil temperature can be extracted from the feature data. After calculating the pressure difference between the predicted virtual pressure and the target pressure, the pressure compensation factor is calculated based on the pressure difference and the current transmission oil temperature. The target electronic control demand current is then solved based on the pressure difference, the pressure compensation factor, and the demand pressure. The compensation amount can be dynamically corrected according to the oil viscosity change caused by the oil temperature, eliminating the oil pressure control deviation caused by oil temperature disturbance, and improving the adaptability and control accuracy of clutch pressure adjustment under different temperature conditions.

[0017] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the step of calculating the target electronic control demand current based on the pressure difference, the pressure compensation factor, and the first demand pressure includes: calculating the demand pressure compensation value of the wet clutch at the current moment based on the pressure difference and the pressure compensation factor; determining the second electronic control demand pressure of the electronic control actuator at the current moment based on the demand pressure compensation value and the first demand pressure; and determining the target electronic control demand current based on the second electronic control demand pressure.

[0018] Based on the above technical solution, the current demand pressure compensation value can be calculated using the pressure difference and pressure compensation factor. The corrected electronic control demand pressure is obtained by superimposing the demand pressure compensation value and the demand pressure. Then, the target electronic control demand current is matched according to the electronic control demand pressure. The pressure control deviation caused by oil temperature and hydraulic lag is offset by the layered oil pressure compensation mechanism, so that the output solenoid valve current is accurately matched with the actual oil pressure demand of the clutch, which significantly improves the oil pressure following effect and control stability of the wet clutch under all working conditions.

[0019] In combination with the first aspect and the above implementation methods, in some possible implementation methods, determining the target electrical control demand current based on the second electrical control demand pressure includes: obtaining a first mapping relationship between the second electrical control demand pressure and the target electrical control demand current; and determining the target electrical control demand current based on the first mapping relationship and the second electrical control demand pressure.

[0020] Based on the above technical solution, a first mapping relationship with a one-to-one correspondence between the second electronic control demand pressure and the target electronic control demand current can be established in advance. Then, the target electronic control demand current can be obtained by matching the second electronic control demand pressure according to the first mapping relationship, eliminating complex real-time conversion calculations and shortening the control calculation time. At the same time, the conversion error caused by the nonlinear characteristics of the solenoid valve itself can be eliminated by relying on the calibration mapping relationship, ensuring that the pressure to current conversion process is accurate and efficient.

[0021] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the step of calculating the pressure compensation factor based on the pressure difference and the current transmission oil temperature includes: obtaining a second mapping relationship between the pressure difference, the current transmission oil temperature and the pressure compensation factor; and calculating the pressure compensation factor based on the second mapping relationship, the pressure difference and the current transmission oil temperature.

[0022] Based on the above technical solution, a second mapping relationship can be pre-constructed between the pressure difference, the current transmission oil temperature, and the pressure compensation factor. By combining the second mapping relationship, the pressure difference, and the current transmission oil temperature, a suitable pressure compensation factor can be obtained. Based on the characteristics of oil viscosity changing with temperature, segmented and accurate compensation can be achieved, eliminating complex real-time iterative calculations, reducing the computing power consumption of the controller, and effectively eliminating oil pressure control errors caused by hydraulic system disturbances under different oil temperature conditions, thereby improving the robustness of wet clutch pressure regulation across the entire temperature range.

[0023] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the step of calculating the demand pressure change rate of the wet clutch at the current moment based on the first demand pressure includes: obtaining the second demand pressure of the wet clutch at the target moment; calculating the demand pressure change value of the wet clutch at the current moment based on the first demand pressure and the second demand pressure; and calculating the demand pressure change rate based on the demand pressure change value.

[0024] Based on the above technical solution, the second demand pressure of the wet clutch at the target time can be obtained first, and the demand pressure change value can be calculated in combination with the first demand pressure. Then, the demand pressure change rate can be solved. Relying on the oil pressure data before and after the time sequence, the dynamic speed of hydraulic adjustment can be accurately characterized, providing an accurate basis for subsequent delay correction, variable parameter PID gain matching and oil temperature and pressure compensation. It can accurately identify the hydraulic hysteresis difference under different adjustment rates and reduce the deviation of oil pressure prediction and current control from the source.

[0025] Secondly, a control device for a vehicle wet clutch is provided, comprising: an extraction module for collecting feature data of the wet clutch at multiple moments, and extracting a first target pressure and a first actual pressure of the wet clutch at the current moment from the feature data; a calculation module for calculating a first demand pressure of the wet clutch at the current moment based on the first target pressure and the first actual pressure, and calculating a demand pressure change rate of the wet clutch at the current moment based on the first demand pressure; and a control module for determining a first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate, and determining a target electronic control demand current of the electronic control actuator in the wet clutch at the current moment based on the first predicted virtual pressure and the first demand pressure, so as to control the operation of the wet clutch using the target electronic control demand current.

[0026] The vehicle wet clutch control device of this application embodiment can extract the target pressure and actual pressure at the current moment from the characteristic data of the wet clutch at multiple moments, thereby determining the demand pressure at the current moment, and calculating the corresponding demand pressure change rate based on the demand pressure, thereby obtaining the first predicted virtual pressure of the wet clutch at the current moment, and then determining the target electronic control demand current of the electronic control actuator at the current moment to realize the control operation of the wet clutch. It can fully take into account the dynamic characteristics of hydraulic timing, while accelerating the oil pressure response speed and enhancing control stability and robustness, eliminating oil pressure overshoot and response lag problems, and significantly improving the overall vehicle driving comfort.

[0027] In conjunction with the second aspect, in some possible implementations, the calculation module includes: a first extraction unit, configured to acquire the first electronically controlled demand pressure of the electronically controlled actuator at the previous moment, and extract the second target pressure and the second actual pressure of the wet clutch at the previous moment from the feature data; a first calculation unit, configured to calculate the pressure feedforward value of the first demand pressure based on the first target pressure and the second target pressure; a second calculation unit, configured to calculate the first pressure error value of the wet clutch at the current moment based on the first target pressure and the first actual pressure; and a third calculation unit, configured to calculate the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value.

[0028] Based on the above technical solution, the electrical control demand pressure of the electronically controlled actuator at the previous moment can be retrieved, and the target oil pressure and actual oil pressure of the wet clutch at the previous moment can be extracted from the feature data. Then, the pressure feedforward value can be calculated based on the difference between the target pressure at the current moment and the target pressure at the previous moment, and the pressure error value at the current moment can be calculated based on the target pressure and actual pressure at the current moment. Thus, the demand pressure at the current moment can be obtained by solving the electrical control demand pressure, pressure feedforward value and pressure error value at the previous moment. By introducing time-series historical control parameters and operating state parameters to construct a feedforward superimposed feedback demand oil pressure calculation mechanism, the inherent hysteresis and inertia characteristics of the wet clutch electromechanical-hydraulic strong coupling system can be specifically compensated, effectively reducing the deviation in the dynamic pressure adjustment process and simultaneously improving the pressure response speed and control accuracy of the wet clutch.

[0029] In conjunction with the second aspect and the above implementation methods, in some possible implementation methods, the third calculation unit includes: a first determining subunit, configured to determine, based on the first pressure error value, a first proportional gain value, an integral gain value, and a first differential gain value required for calculating the first demand pressure at the current moment; a second determining subunit, configured to determine, based on the second pressure error value of the wet clutch at the previous moment, a second proportional gain value and a second differential gain value required for calculating the first demand pressure at the previous moment; and a first calculation subunit, configured to calculate the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, the first pressure error value, the first proportional gain value, the integral gain value, the first differential gain value, the second proportional gain value, and the second differential gain value.

[0030] Based on the above technical solution, the corresponding proportional, integral, and derivative gains can be matched according to the pressure error value at the current moment. At the same time, the historical proportional and derivative gains can be obtained by combining the historical pressure error value at the previous moment. The current demand pressure can be solved by integrating the electronic control demand pressure, pressure feedforward value, proportional gain, integral gain, derivative gain, historical proportional gain, and historical derivative gain. By distinguishing between the current and historical errors and configuring differentiated PID gains, variable parameter composite PID control can be achieved. This can adapt to the hysteresis inertia characteristics of the dynamic changes in the wet clutch electro-hydraulic coupling system, effectively reduce the dynamic adjustment deviation of oil pressure, suppress pressure overshoot and response lag, and significantly improve the real-time performance, stability, and robustness of oil pressure control.

[0031] In conjunction with the second aspect and the above implementation methods, in some possible implementation methods, the control module includes: a first determining unit, configured to determine the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure; a second determining unit, configured to determine the pressure delay coefficient of the wet clutch at the current moment based on the demand pressure change rate, and obtain the pressure delay correction coefficient of the wet clutch at the current moment; and a third determining unit, configured to determine the first predicted virtual pressure based on the first demand pressure, the second predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient.

[0032] Based on the above technical solution, the corresponding historical predicted virtual pressure can be obtained from the actual pressure at the previous moment. The pressure delay coefficient can be solved by combining the current demand pressure change rate and matching the pressure delay correction coefficient. Then, the predicted virtual oil pressure at the current moment can be calculated based on the current demand pressure, the historical predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient. By introducing the time-series virtual pressure and the layered delay correction mechanism, the inherent lag characteristics of the hydraulic transmission of the wet clutch can be accurately compensated, the oil pressure prediction deviation can be reduced, and a reliable pressure reference can be provided for the subsequent precise control of the solenoid valve current, thereby improving the overall pressure control stability and following performance.

[0033] In conjunction with the second aspect and the above implementation methods, some possible implementation methods may further include: an acquisition module, configured to acquire the oil filling status identification information of the wet clutch before determining the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure; and a determination module, configured to determine the second predicted virtual pressure based on the oil filling status identification information and the second actual pressure when the oil filling status identification information meets the preset oil filling conditions.

[0034] Based on the above technical solution, before determining the historical predicted virtual pressure at the previous moment, the oil filling status identification information of the wet clutch can be collected first. If the oil filling status identification information meets the preset oil filling conditions, the second predicted virtual pressure can be calculated based on the oil filling status identification information and the actual pressure at the previous moment. This distinguishes the virtual pressure benchmark constructed differently between the oil filling and non-oil filling stages of the clutch, avoids the interference of oil pressure fluctuations during the oil filling stage on the prediction accuracy, and makes the virtual pressure result fit the actual hydraulic oil filling dynamic process of the clutch, ensuring the accuracy of subsequent pressure delay correction and current control.

[0035] In conjunction with the second aspect and the above implementation methods, in some possible implementations, the control module includes: a second extraction unit for extracting the current transmission oil temperature of the wet clutch from the feature data; a fourth calculation unit for calculating the pressure difference between the first predicted virtual pressure and the first target pressure; a fifth calculation unit for calculating a pressure compensation factor based on the pressure difference and the current transmission oil temperature; and a sixth calculation unit for calculating the target electronic control demand current based on the pressure difference, the pressure compensation factor, and the first demand pressure.

[0036] Based on the above technical solution, the current transmission oil temperature can be extracted from the feature data. After calculating the pressure difference between the predicted virtual pressure and the target pressure, the pressure compensation factor is calculated based on the pressure difference and the current transmission oil temperature. The target electronic control demand current is then solved based on the pressure difference, the pressure compensation factor, and the demand pressure. The compensation amount can be dynamically corrected according to the oil viscosity change caused by the oil temperature, eliminating the oil pressure control deviation caused by oil temperature disturbance, and improving the adaptability and control accuracy of clutch pressure adjustment under different temperature conditions.

[0037] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the sixth calculation unit includes: a second calculation subunit, used to calculate the current demand pressure compensation value of the wet clutch based on the pressure difference and the pressure compensation factor; a third determination subunit, used to determine the current second electronic control demand pressure of the electronic control actuator based on the demand pressure compensation value and the first demand pressure; and a fourth determination subunit, used to determine the target electronic control demand current based on the second electronic control demand pressure.

[0038] Based on the above technical solution, the current demand pressure compensation value can be calculated using the pressure difference and pressure compensation factor. The corrected electronic control demand pressure is obtained by superimposing the demand pressure compensation value and the demand pressure. Then, the target electronic control demand current is matched according to the electronic control demand pressure. The pressure control deviation caused by oil temperature and hydraulic lag is offset by the layered oil pressure compensation mechanism, so that the output solenoid valve current is accurately matched with the actual oil pressure demand of the clutch, which significantly improves the oil pressure following effect and control stability of the wet clutch under all working conditions.

[0039] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the fourth determining subunit includes: an acquisition subunit, used to acquire a first mapping relationship between the second electronic control demand pressure and the target electronic control demand current; and a determining subunit, used to determine the target electronic control demand current based on the first mapping relationship and the second electronic control demand pressure.

[0040] Based on the above technical solution, a first mapping relationship with a one-to-one correspondence between the second electronic control demand pressure and the target electronic control demand current can be established in advance. Then, the target electronic control demand current can be obtained by matching the second electronic control demand pressure according to the first mapping relationship, eliminating complex real-time conversion calculations and shortening the control calculation time. At the same time, the conversion error caused by the nonlinear characteristics of the solenoid valve itself can be eliminated by relying on the calibration mapping relationship, ensuring that the pressure to current conversion process is accurate and efficient.

[0041] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the fifth calculation unit includes: an acquisition subunit, used to acquire a second mapping relationship between the pressure difference, the current transmission oil temperature and the pressure compensation factor; and a third calculation subunit, used to calculate the pressure compensation factor based on the second mapping relationship, the pressure difference and the current transmission oil temperature.

[0042] Based on the above technical solution, a second mapping relationship can be pre-constructed between the pressure difference, the current transmission oil temperature, and the pressure compensation factor. By combining the second mapping relationship, the pressure difference, and the current transmission oil temperature, a suitable pressure compensation factor can be obtained. Based on the characteristics of oil viscosity changing with temperature, segmented and accurate compensation can be achieved, eliminating complex real-time iterative calculations, reducing the computing power consumption of the controller, and effectively eliminating oil pressure control errors caused by hydraulic system disturbances under different oil temperature conditions, thereby improving the robustness of wet clutch pressure regulation across the entire temperature range.

[0043] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the calculation module includes: an acquisition unit for acquiring the second demand pressure of the wet clutch at a target time; a seventh calculation unit for calculating the demand pressure change value of the wet clutch at the current time based on the first demand pressure and the second demand pressure; and an eighth calculation unit for calculating the demand pressure change rate based on the demand pressure change value.

[0044] Based on the above technical solution, the second demand pressure of the wet clutch at the target time can be obtained first, and the demand pressure change value can be calculated in combination with the first demand pressure. Then, the demand pressure change rate can be solved. Relying on the oil pressure data before and after the time sequence, the dynamic speed of hydraulic adjustment can be accurately characterized, providing an accurate basis for subsequent delay correction, variable parameter PID gain matching and oil temperature and pressure compensation. It can accurately identify the hydraulic hysteresis difference under different adjustment rates and reduce the deviation of oil pressure prediction and current control from the source.

[0045] Thirdly, a vehicle is provided, the vehicle comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the vehicle wet clutch control method of the first aspect or any possible implementation thereof.

[0046] Fourthly, a computer-readable storage medium is provided that stores a computer program, which, when executed by a processor, implements the above-described control method for a vehicle wet clutch.

[0047] Fifthly, a computer program product is provided, including a computer program that, when executed, implements the above-described control method for a vehicle wet clutch. Attached Figure Description

[0048] Figure 1 This is a flowchart of a vehicle wet clutch control method according to an embodiment of this application; Figure 2 This is a flowchart illustrating the calculation of demand pressure according to one embodiment of this application; Figure 3 This is a flowchart illustrating the construction of a wet clutch pressure prediction model according to one embodiment of this application; Figure 4 This is a flowchart illustrating the working principle of a vehicle wet clutch control method according to an embodiment of this application; Figure 5 This is a schematic diagram of the structure of a wet clutch pressure control device according to an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application. Detailed Implementation

[0049] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0050] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0051] Wet clutch pressure control is one of the core technologies of automatic transmission systems, and its control quality directly affects the vehicle's response speed, driving smoothness, and durability. During vehicle operation, the vehicle controller first determines the target clutch torque based on the driver's intentions, such as the lever position, brake status, accelerator pedal position and its rate of change, as well as the current engine operating status and vehicle driving status. Then, it further calculates the target clutch pressure based on the clutch friction characteristics. Therefore, quickly and accurately achieving this target pressure is a fundamental prerequisite for achieving the vehicle control objectives.

[0052] In order to address the highly nonlinear problem of wet clutch systems, wet clutch pressure control technology generally uses a "desired pressure + closed-loop feedback (such as PID)" control method to calculate the requested pressure of the clutch solenoid valve, and then calculates the target current from the pressure-current characteristic curve of the solenoid valve, thereby achieving clutch pressure control.

[0053] However, the following problems exist in the related technologies: 1) As a highly electromechanical-hydraulic coupled nonlinear system, the wet clutch system suffers from significant system hysteresis. The achievement of the clutch target pressure is not only related to the control parameters at the current moment, but also closely related to the control process at the previous moment or even several moments prior. The optimization strategies in the related technologies only compensate for the demand pressure or target current based on parameters such as the current demand pressure, actual pressure, and transmission oil temperature, without considering the system's inertia and hysteresis characteristics. This fails to avoid clutch pressure overshoot or delay, resulting in poor stability and robustness of pressure control; 2) In the optimization compensation strategies of the related technologies, neither the pressure compensation value nor the current compensation value is related to the actual operating conditions of the vehicle. They lack the ability to predict pressure, making it difficult to cover the differences in physical characteristics under different operating conditions and between different solenoid valves, and consistency is difficult to guarantee.

[0054] Therefore, to solve the above problems, a control method for a vehicle wet clutch is provided. This method can extract the target pressure and actual pressure at the current moment from the characteristic data of the wet clutch at multiple moments, thereby determining the demand pressure at the current moment. Based on the demand pressure, the corresponding demand pressure change rate is calculated to obtain the first predicted virtual pressure of the wet clutch at the current moment. Then, the target electronic control demand current of the electronic control actuator at the current moment is determined to realize the control operation of the wet clutch. This solves the problems in related technologies, such as using only instantaneous operating condition parameters to compensate for oil pressure and current, not considering the system inertial hysteresis which easily leads to oil pressure overshoot and response lag, and the compensation amount not being combined with the overall vehicle operating conditions, lacking oil pressure prediction capability, being unable to adapt to multiple operating conditions and differences in solenoid valve characteristics, and having poor oil pressure control stability, robustness, and consistency. This method achieves the technical effect of fully taking into account the dynamic characteristics of hydraulic timing, accelerating the oil pressure response speed while enhancing control stability and robustness, eliminating oil pressure overshoot and response lag problems, and significantly improving the overall vehicle driving comfort.

[0055] The control method of the vehicle wet clutch according to an embodiment of this application will be illustrated below with reference to the accompanying drawings.

[0056] Figure 1 This is a flowchart of a vehicle wet clutch control method according to an embodiment of this application.

[0057] like Figure 1 As shown, the vehicle wet clutch control method of this application embodiment includes the following steps: S101: Collect feature data of the wet clutch at multiple moments, and extract the first target pressure and the first actual pressure of the wet clutch at the current moment from the feature data.

[0058] Specifically, the characteristic data may include, but is not limited to, the target pressure of the wet clutch at different times, under different external environments and different driving conditions, the electronic control demand pressure of the electronic actuator, such as the solenoid valve demand pressure, the clutch oil filling process, the clutch half-engagement point, the actual pressure, the transmission oil temperature, etc.; it can be obtained through vehicle road tests, high temperature tests, cold weather tests and high altitude tests.

[0059] The first target pressure can be understood as the ideal hydraulic pressure of the wet clutch, which is the set value that the controller wants to achieve. It can be calculated based on the clutch target torque and clutch friction characteristics. The first actual pressure can be understood as the real real-time hydraulic pressure of the wet clutch obtained by direct measurement, which is the feedback measurement value of the system.

[0060] This application embodiment can collect feature data of the wet clutch at multiple moments, and extract the first target pressure and the first actual pressure of the wet clutch at the current moment from the feature data.

[0061] For example, embodiments of this application can obtain characteristic data of the wet clutch under different times, different external environments, and different driving conditions through vehicle road tests, high-temperature tests, low-temperature tests, and high-altitude tests. This data includes target pressure, solenoid valve required pressure, clutch oil filling process, clutch half-engagement point, actual pressure, and transmission oil temperature. It should be noted that driving conditions may include, but are not limited to, vehicle crawling and starting / shifting conditions at various throttle positions. Particular attention is paid to starting and shifting under conditions of rapid throttle application and release, as well as different degrees of braking. This is because frequent changes in driver intent during vehicle operation, such as repeated throttle and brake applications, can easily lead to an accumulation of clutch pressure control errors, or even loss of control.

[0062] S102, based on the first target pressure and the first actual pressure, calculate the first demand pressure of the wet clutch at the current moment, and based on the first demand pressure, calculate the rate of change of demand pressure of the wet clutch at the current moment.

[0063] Specifically, the first demand pressure refers to the current output command oil pressure output to the solenoid valve based on the first target pressure and the first actual pressure. It is the pressure command value that the solenoid valve needs to output in real time.

[0064] The embodiments of this application can calculate the first demand pressure of the wet clutch at the current moment based on the first target pressure and the first actual pressure corresponding to the current moment, and solve the demand pressure change rate at the corresponding moment based on the first demand pressure.

[0065] For example, embodiments of this application can calculate the first demand pressure of the wet clutch at the current moment by combining feedforward and PID control, and then calculate the demand pressure change rate based on the first demand pressure.

[0066] In some embodiments of this application, calculating the demand pressure change rate of the wet clutch at the current moment based on the first demand pressure includes: obtaining the second demand pressure of the wet clutch at the target moment; calculating the demand pressure change value of the wet clutch at the current moment based on the first demand pressure and the second demand pressure; and calculating the demand pressure change rate based on the demand pressure change value.

[0067] Specifically, the target time can be understood as a historical time, which is different from the current time; while the second demand pressure can be understood as the clutch hydraulic pressure calculated for the target time.

[0068] The change in demand pressure refers to the difference between the first demand pressure at the current moment and the pressure at the second moment at the target moment, which is used to characterize the total magnitude of the oil pressure command adjustment from the target moment to the current moment.

[0069] This application embodiment can obtain the second required oil pressure of the wet clutch at a target time, combine it with the first required pressure at the current time, calculate the change value of the required pressure of the wet clutch at the current time, and solve for the rate of change of required pressure based on the change value. Wherein, the required pressure of the wet clutch... The formula for calculating the change in demand pressure over a period of time can be, but is not limited to, expressed as: , For example, if Taking four control software task cycles as the calculation duration, the formula for calculating the change in demand pressure can be, but is not limited to, expressed as: , in, This represents the change in the required pressure of the clutch at the current moment. This indicates the initial demand pressure of the clutch at the current moment. This indicates the second demand pressure of the clutch during the previous four task periods.

[0070] To improve the stability of clutch pressure control, a time-domain average filter is applied to the demand pressure change value, with a filter window length of four control software task cycles. The clutch demand pressure change rate... The calculation formula can be, but is not limited to, the following: , In some embodiments of this application, calculating the first demand pressure of the wet clutch at the current moment based on the first target pressure and the first actual pressure includes: obtaining the first electronically controlled demand pressure of the electronically controlled actuator at the previous moment, and extracting the second target pressure and the second actual pressure of the wet clutch at the previous moment from feature data; calculating the pressure feedforward value of the first demand pressure based on the first target pressure and the second target pressure; calculating the first pressure error value of the wet clutch at the current moment based on the first target pressure and the first actual pressure; and calculating the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value.

[0071] The embodiments of this application can extract the second target pressure of the wet clutch at the previous moment from the feature data, and then combine it with the first target pressure to calculate the pressure feedforward value.

[0072] The formula for calculating the pressure feedforward value can be, but is not limited to, expressed as: = - , in, This indicates the first target pressure of the wet clutch at the current moment. This represents the second target pressure of the wet clutch at the previous moment. This represents the pressure feedforward value.

[0073] The embodiments of this application can calculate the first pressure error value of the wet clutch at the current moment based on the first target pressure and the first actual pressure.

[0074] The formula for calculating the first pressure error value can be, but is not limited to, expressed as: = - , in, This indicates the first pressure error value of the wet clutch at the current moment. This indicates the first target pressure of the wet clutch at the current moment. This indicates the first actual pressure of the wet clutch at the current moment.

[0075] Furthermore, in this embodiment of the application, the first electrical control demand pressure of the electrical control actuator at the previous moment is obtained, and then the first demand pressure is calculated by combining the pressure feedforward value and the first pressure error value.

[0076] In some embodiments of this application, calculating the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value includes: determining, based on the first pressure error value, the first proportional gain value, the integral gain value, and the first derivative gain value required for calculating the first demand pressure at the current moment; determining, based on the second pressure error value of the wet clutch at the previous moment, the second proportional gain value and the second derivative gain value required for calculating the first demand pressure at the previous moment; and calculating the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, the first pressure error value, the first proportional gain value, the integral gain value, the first derivative gain value, the second proportional gain value, and the second derivative gain value.

[0077] Specifically, embodiments of this application can be based on a first pressure error value. The first proportional gain value, integral gain value, and first derivative gain value are calculated from a table based on the transmission oil temperature. It should be noted that, in this embodiment, different PID gains can be set for different oil temperatures and pressure errors based on the hysteresis effect of the oil at different temperatures and the comprehensive requirements for pressure response speed and stability under different pressure errors, thereby improving the response speed while ensuring stability.

[0078] In this embodiment, the first proportional gain value, integral gain value, and first differential gain value used to solve the first demand pressure can be determined based on the first pressure error value at the current moment. The second proportional gain value and second differential gain value used to solve the first demand oil pressure can be determined based on the second pressure error value of the wet clutch at the previous moment. Then, the first demand pressure is calculated based on the first electronically controlled demand pressure, pressure feedforward value, first pressure error value, first proportional gain value, integral gain value, first differential gain value, second proportional gain value, and second differential gain value.

[0079] The formula for calculating the first demand pressure can be, but is not limited to, expressed as: , in, This indicates the first demand pressure of the wet clutch at the current moment. This indicates the pressure of demand for the first type of electronic control system. Indicates the pressure feedforward value. This represents the first proportional gain value of the wet clutch at the current moment. This indicates the first pressure error value of the wet clutch at the current moment. This represents the second proportional gain value of the wet clutch at the previous moment. This represents the second pressure error value of the wet clutch at the previous moment. This represents the integral gain value of the wet clutch at the current moment. This represents the first differential gain value of the wet clutch at the current moment. This represents the second differential gain value of the wet clutch at the previous moment. This indicates the pressure error value of the wet clutch at the previous two moments.

[0080] For example, embodiments of this application can calculate the content of the first demand pressure based on a feedforward and incremental PI control algorithm, such as... Figure 2 As shown, it mainly includes: Step S201: Calculate the difference between the first target pressure at the current moment and the second target pressure at the previous moment for the wet clutch as the pressure feedforward value of the first demand pressure.

[0081] The formula for calculating the pressure feedforward value is as shown above, and will not be elaborated further here.

[0082] Step S202: Calculate the difference between the first target pressure and the first actual pressure of the wet clutch at the current moment as the first pressure error value of the wet clutch closed-loop control.

[0083] The formula for calculating the first pressure error value is as shown above, and will not be elaborated further here.

[0084] Step S203: Calculate the proportional gain, integral gain, and derivative gain based on the first pressure error value and the transmission oil temperature by referring to the table.

[0085] Step S204: Calculate the first demand pressure based on the feedforward and incremental PID control algorithm.

[0086] The formula for calculating the first demand pressure is as shown above, and will not be elaborated further here.

[0087] S103, determine the first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate, and determine the target electronic control demand current of the electronic control actuator in the wet clutch at the current moment based on the first predicted virtual pressure and the first demand pressure, so as to control the operation of the wet clutch by using the target electronic control demand current.

[0088] Specifically, the first predicted virtual pressure can be understood as the theoretically estimated oil pressure calculated based on the first demand pressure and the rate of change of demand pressure. It is a virtual calculation and not the actual oil pressure measured by the sensor.

[0089] The electronically controlled actuator is used to change the flow rate of oil entering the clutch piston chamber, thereby regulating the oil pressure. It can be understood as a solenoid valve that is matched with a wet clutch.

[0090] The target electrical control current requirement can be understood as the standard drive current value that the controller ultimately outputs and sends to the solenoid valve; it is an electrical signal control quantity.

[0091] The embodiments of this application can obtain the first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate at the current moment, and output the target electronic control demand current of the electronic control actuator in the wet clutch at the current moment by combining the first predicted virtual pressure and the first demand pressure, and then realize the drive control of the wet clutch through the target electronic control demand current.

[0092] For example, embodiments of this application can create a wet clutch pressure prediction model based on digital twins based on feature data. Then, based on the first demand pressure, the demand pressure change rate, and the transmission oil temperature, the wet clutch pressure prediction model calculates the first predicted virtual pressure of the wet clutch at the current moment. Combining the first predicted virtual pressure and the first demand pressure, the first demand pressure is optimized and compensated. The target electronic control demand pressure and target electronic control demand current of the solenoid valve at the current moment are calculated, thereby realizing the drive control of the wet clutch.

[0093] In addition, the wet clutch pressure prediction model in this application embodiment is a pressure control strategy after the wet clutch is filled with oil. Therefore, before entering the wet clutch closed-loop pressure control logic, it must be ensured that the wet clutch is filled with oil.

[0094] In some embodiments of this application, before determining the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure, the method further includes: obtaining the oil filling status identification information of the wet clutch; and when the oil filling status identification information meets the preset oil filling conditions, determining the second predicted virtual pressure based on the oil filling status identification information and the second actual pressure.

[0095] Specifically, the second predicted virtual pressure can be understood as the hydraulic estimated virtual oil pressure calculated at the previous moment, not the actual measured value of the sensor, but the theoretical oil pressure calculated by the controller based on the simulation of hydraulic dynamic characteristics.

[0096] The oil filling status identifier information is used to characterize the current oil filling process of the wet clutch oil chamber. It is a Boolean / enumerated state variable, which may include, but is not limited to, no oil filling, pre-filling, rapid oil filling, oil filling completed, pressure holding, and oil release. In this embodiment of the application, before determining the second predicted virtual pressure corresponding to the previous moment of the wet clutch based on the second actual pressure, the oil filling status identification information of the wet clutch is first collected. When the oil filling status identification information meets the preset oil filling conditions, the second predicted virtual pressure is obtained by combining the oil filling status identification information and the second actual pressure. The preset oil filling conditions can be set by those skilled in the art according to actual conditions, and this application does not impose specific limitations.

[0097] For example, in this embodiment of the application, before determining the second predicted virtual pressure corresponding to the previous moment of the wet clutch based on the second actual pressure, it can first determine whether the clutch oil filling process is greater than 99%. If so, it is determined that the oil filling status indicator information meets the preset oil filling conditions, the wet clutch oil filling is completed, and then the second predicted virtual pressure is determined based on the oil filling status indicator information and the second actual pressure, that is, the second predicted virtual pressure is initialized to the second actual pressure. .

[0098] In some embodiments of this application, determining the first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate includes: determining the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure; determining the pressure delay coefficient of the wet clutch at the current moment based on the demand pressure change rate, and obtaining the pressure delay correction coefficient of the wet clutch at the current moment; and determining the first predicted virtual pressure based on the first demand pressure, the second predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient.

[0099] Specifically, in this embodiment of the application, a wet clutch pressure prediction model can be used to determine the first predicted virtual pressure. The content of the wet clutch pressure prediction model constructed in this embodiment of the application is as follows: Figure 3 As shown, it mainly includes: Step S301: Create an input signal preprocessing module to initialize the predicted virtual pressure to the actual pressure.

[0100] In this embodiment, the predicted virtual pressure can be initialized based on the clutch target pressure and the clutch filling process, that is, the second predicted virtual pressure is initialized as the second actual pressure.

[0101] Step S302: Calculate the pressure delay coefficient by referring to the table based on the demand pressure change rate and transmission oil temperature.

[0102] The factors influencing the pressure delay coefficient may include, but are not limited to, the response delay of the clutch solenoid valve's electromagnetic force, and the response delay caused by hydraulic forces, viscous forces, and friction during the solenoid valve's operation. Further, the relationship between the pressure delay coefficient, the rate of change of demand pressure, and the transmission oil temperature in this embodiment is shown in Table 1. Table 1 is a table showing the relationship between the pressure delay coefficient, the rate of change of demand pressure, and the transmission oil temperature according to an embodiment of this application.

[0103] Table 1

[0104] Step S303: Determine whether the clutch filling process is greater than 99%. If so, start the clutch pressure prediction timer and calculate the pressure delay correction coefficient by referring to the table based on the clutch pressure prediction timer and the difference between the required pressure and the clutch half engagement point.

[0105] It should be noted that the pressure delay correction coefficient takes into account the possibility of secondary clutch filling after the clutch is filled with oil, which may occur due to insufficient clutch filling and compression deformation of the clutch friction plates after being compressed. This is crucial for pressure prediction in the low-pressure zone. The clutch half-engagement point refers to the clutch piston chamber pressure at the moment when the oil overcomes the clutch spring force to push the clutch piston, and the clutch steel plates and friction plates begin to contact and transmit torque. The relationship between the pressure delay correction coefficient, the clutch pressure prediction timer, the difference between the required pressure and the clutch half-engagement point is shown in Table 2. Table 2 is a table showing the relationship between the pressure delay correction coefficient, the clutch pressure prediction timer, the difference between the required pressure and the clutch half-engagement point according to an embodiment of this application.

[0106] Table 2

[0107] Step S304: Construct a wet clutch pressure prediction model.

[0108] The expression for the wet clutch pressure prediction model can be, but is not limited to, expressed as: , in, The first predicted virtual pressure of the wet clutch at the current moment, calculated by the wet clutch pressure prediction model. The second predicted virtual pressure from the previous moment. The first required pressure for the wet clutch at the current moment is given by MBP, which represents the clutch partial engagement point. This is the pressure delay coefficient. This is the pressure delay correction factor.

[0109] It can be understood that the embodiments of this application can predict the virtual pressure of the wet clutch based on the demand pressure, the rate of change of demand pressure, the transmission oil temperature, the clutch half-engagement point, and the clutch filling process.

[0110] Step S305: Import the feature data into the wet clutch pressure prediction model, and perform simulation tests and parameter calibration on the wet clutch pressure prediction model so that the absolute value of the difference between the predicted virtual pressure and the actual pressure output by the wet clutch pressure prediction model is less than the preset difference threshold.

[0111] In this embodiment of the application, a preset difference threshold is used. The specific settings can be made by those skilled in the art according to the actual situation, and this application does not impose specific restrictions.

[0112] In this embodiment, the second predicted virtual pressure of the wet clutch at the previous moment can be obtained based on the second actual pressure. The pressure delay coefficient of the wet clutch at the current moment can be solved based on the demand pressure change rate, and the pressure delay correction coefficient corresponding to the current moment can be obtained. Then, the first predicted virtual pressure can be calculated by combining the first demand pressure, the second predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient.

[0113] For example, in the embodiments of this application, the predicted virtual pressure can be initialized according to the clutch target pressure and the clutch filling process, that is, the second predicted virtual pressure is initialized as the second actual pressure, and the pressure delay coefficient is determined by Table 1 and the demand pressure change rate and transmission oil temperature, and the pressure delay coefficient is determined by Table 2 and the demand pressure change rate and transmission oil temperature. Then, the predicted virtual pressure of the wet clutch is predicted by the wet clutch pressure prediction model, and the first predicted virtual pressure is determined.

[0114] It can be understood that the embodiments of this application can predict the virtual pressure of the wet clutch based on the current demand pressure of the wet clutch and the rate of change of demand pressure over a previous period of time. This is a prerequisite for stable and effective compensation of the current demand pressure of the wet clutch.

[0115] In some embodiments of this application, determining the target electronic control demand current of the electronically controlled actuator in the wet clutch at the current moment based on the first predicted virtual pressure and the first demand pressure includes: extracting the current transmission oil temperature of the wet clutch from feature data; calculating the pressure difference between the first predicted virtual pressure and the first target pressure; calculating a pressure compensation factor based on the pressure difference and the current transmission oil temperature; and calculating the target electronic control demand current based on the pressure difference, the pressure compensation factor, and the first demand pressure.

[0116] Specifically, the current transmission oil temperature refers to the hydraulic oil temperature collected in real time by the transmission oil pan temperature sensor: low temperature: high oil viscosity, slow hydraulic response, and severe pressure lag; high temperature: low oil viscosity, sensitive oil pressure response, but prone to overshoot.

[0117] The formula for calculating the pressure difference can be, but is not limited to, expressed as: Pressure difference = First predicted virtual pressure The first target pressure is used to estimate the deviation between the predicted virtual pressure and the target pressure.

[0118] The pressure compensation factor is obtained by looking up a table or performing a fitting calculation based on the pressure difference and the current transmission oil temperature.

[0119] This application embodiment can extract the current transmission oil temperature from the collected wet clutch feature data, calculate the pressure difference between the first predicted virtual pressure and the first target pressure, and then combine the pressure difference and the current transmission oil temperature to solve the pressure compensation factor, and calculate the target electronic control demand current based on the pressure difference, the pressure compensation factor and the first demand pressure.

[0120] For example, in this embodiment of the application, the pressure difference between the first predicted virtual pressure and the first target pressure can be calculated first, and the current transmission oil temperature of the wet clutch can be obtained. Then, the pressure compensation factor can be calculated by looking up a table, and the target electronic control demand current can be calculated based on the pressure difference, the pressure compensation factor and the first demand pressure.

[0121] In some embodiments of this application, the target electronic control demand current is calculated based on the pressure difference, pressure compensation factor, and first demand pressure, including: calculating the demand pressure compensation value of the wet clutch at the current moment based on the pressure difference and pressure compensation factor; determining the second electronic control demand pressure of the electronic control actuator at the current moment based on the demand pressure compensation value and the first demand pressure; and determining the target electronic control demand current based on the second electronic control demand pressure.

[0122] The embodiments of this application can calculate the required pressure compensation value of the wet clutch at the current moment based on the pressure difference and the pressure compensation factor.

[0123] The formula for calculating the demand pressure compensation value can be, but is not limited to, expressed as: , in, This represents the demand pressure compensation value. Indicates the stress compensation factor. This represents the pressure difference between the first predicted virtual pressure and the first target pressure.

[0124] The embodiments of this application can determine the second electronic control demand pressure of the electronic control actuator at the current moment based on the demand pressure compensation value and the first demand pressure.

[0125] The formula for calculating the second electronically controlled pressure demand can be, but is not limited to, expressed as: , in, This indicates the pressure of demand for the second type of electronic control system.

[0126] The implementation of this application can determine the target electrical control demand current based on the second electrical control demand pressure.

[0127] For example, embodiments of this application can calculate the target electrical control current requirement based on the pressure-current characteristic curve of the solenoid valve.

[0128] In some embodiments of this application, determining the target electrical control demand current based on the second electrical control demand pressure includes: obtaining a first mapping relationship between the second electrical control demand pressure and the target electrical control demand current; and determining the target electrical control demand current based on the first mapping relationship and the second electrical control demand pressure.

[0129] Specifically, the first mapping relationship can be understood as a one-to-one correspondence between the second electronic control demand pressure and the target electronic control demand current. It can be characterized by a discrete two-dimensional table, a first / secondary polynomial fitting formula, or an independent mapping curve for different pressure ranges. This application does not impose any specific limitations.

[0130] The embodiments of this application can obtain a first mapping relationship between the second electronic control demand pressure and the target electronic control demand current, and then obtain the target electronic control demand current by matching the first mapping relationship and the second electronic control demand pressure.

[0131] In some embodiments of this application, a pressure compensation factor is calculated based on the pressure difference and the current transmission oil temperature, including: obtaining a second mapping relationship between the pressure difference, the current transmission oil temperature, and the pressure compensation factor; and calculating the pressure compensation factor based on the second mapping relationship, the pressure difference, and the current transmission oil temperature.

[0132] Specifically, the second mapping relationship is used to characterize the corresponding rule where the input is the pressure difference and the current transmission oil temperature, and the output is the pressure compensation factor.

[0133] The embodiments of this application can obtain a second mapping relationship between the pressure difference, the current transmission oil temperature, and the pressure compensation factor, and solve for the pressure compensation factor based on the second mapping relationship, the pressure difference, and the current transmission oil temperature.

[0134] The control method for a vehicle wet clutch proposed in this application is described below with reference to several embodiments.

[0135] Example 1: Specifically, Figure 4This is a flowchart illustrating the working principle of a vehicle wet clutch control method according to an embodiment of this application.

[0136] Step S401: Data acquisition.

[0137] In this application embodiment, the characteristic data of the wet clutch under different times, different external environments and different driving conditions can be obtained through vehicle road tests, high temperature tests, cold tests and high altitude tests, such as target pressure, solenoid valve required pressure, clutch oil filling process, clutch half engagement point, actual pressure, transmission oil temperature, etc.

[0138] Step S402: Construct a wet clutch pressure prediction model.

[0139] The content of the wet clutch pressure prediction model constructed in this application embodiment is as follows: Figure 3 As shown, I will not go into further detail here.

[0140] Step S403: Determine if the oil filling flag is true.

[0141] In this embodiment of the application, if the oil filling flag is true, it is determined that the oil filling status identification information meets the preset oil filling conditions, and step S405 is executed; otherwise, step S404 is executed.

[0142] Step S404: Fill with oil and wait.

[0143] Step S405: Calculate the first demand pressure.

[0144] The formula for calculating the first demand pressure is as shown above, and will not be elaborated further here.

[0145] Step S406: Calculate the first predicted virtual pressure.

[0146] In this embodiment, a wet clutch pressure prediction model can be used to output a first predicted virtual pressure.

[0147] Step S407: Determine the target current requirement of the electronic control system.

[0148] In this embodiment, the target electrical control current requirement can be calculated based on the pressure-current characteristic curve of the solenoid valve.

[0149] Example 2: Specifically, Figure 5 This is a schematic diagram of the structure of a wet clutch pressure control device according to an embodiment of this application.

[0150] like Figure 5As shown, the wet clutch pressure control device includes an input signal processing module 100, a control signal acquisition module 200, a wet clutch pressure closed-loop control module 300, a digital twin wet clutch pressure prediction model module 400, and a wet clutch demand pressure compensation module 500.

[0151] The input signal processing module 100 is used to acquire the first actual pressure of the wet clutch and the current transmission oil temperature in real time through sensors, and to perform filtering processing.

[0152] The control signal acquisition module 200 is used to acquire the target pressure, clutch half-engagement point, and clutch oil filling flag of the wet clutch.

[0153] The wet clutch pressure closed-loop control module 300 is used to calculate the required pressure based on the target pressure, actual pressure, and transmission oil temperature.

[0154] Among them, the closed-loop control of wet clutch pressure can be understood as an optimized feedforward and incremental PID control that improves the pressure response of wet clutch while ensuring that the pressure does not overshoot.

[0155] The digital twin wet clutch pressure prediction model module 400 is used to predict the virtual pressure of the wet clutch based on the demand pressure, the rate of change of demand pressure, the actual pressure, and the transmission oil temperature.

[0156] This can be understood as predicting the hysteresis relationship between the actual pressure and the demand pressure of the wet clutch based on the first demand pressure of the wet clutch at the current moment and the control trend over a period of time, thereby further improving the pressure response speed of the wet clutch and avoiding the impact on the whole vehicle caused by the overshoot of the wet clutch pressure.

[0157] The wet clutch demand pressure compensation module 500 is used to calculate the demand pressure compensation value based on the predicted virtual pressure, actual pressure and transmission oil temperature, and to calculate the solenoid valve's electronic control demand pressure and target electronic control demand current based on the demand pressure compensation value and the demand pressure, so as to achieve precise control of the wet clutch pressure.

[0158] In summary, the vehicle wet clutch control method of this application embodiment can extract the target pressure and actual pressure at the current moment from the characteristic data of the wet clutch at multiple moments, thereby determining the demand pressure at the current moment, and calculating the corresponding demand pressure change rate based on the demand pressure, thus obtaining the first predicted virtual pressure of the wet clutch at the current moment, and then determining the target electronic control demand current of the electronic control actuator at the current moment to realize the control operation of the wet clutch. Thus, it solves the problems in related technologies that only use instantaneous operating condition parameters to compensate for oil pressure and current, without considering the system inertial hysteresis which can easily lead to oil pressure overshoot and response lag, and the compensation amount does not combine the overall vehicle operating conditions, lacks oil pressure prediction capability, cannot adapt to multiple operating conditions and differences in solenoid valve characteristics, and has poor oil pressure control stability, robustness and consistency. It achieves the technical effect of fully taking into account the dynamic characteristics of hydraulic timing, accelerating the oil pressure response speed while enhancing control stability and robustness, eliminating oil pressure overshoot and response lag problems, and significantly improving the overall vehicle driving comfort.

[0159] Figure 6 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application. The vehicle may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0160] When the processor 602 executes the program, it implements the vehicle wet clutch control method provided in the above embodiments.

[0161] Furthermore, the vehicle also includes: Communication interface 603 is used for communication between memory 601 and processor 602.

[0162] The memory 601 is used to store computer programs that can run on the processor 602.

[0163] The memory 601 may include high-speed RAM (Random Access Memory) memory, and may also include non-volatile memory, such as at least one disk storage.

[0164] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0165] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0166] The processor 602 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of this application.

[0167] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described vehicle wet clutch control method.

[0168] This application also provides a computer program product, including a computer program that, when executed, implements the above-described vehicle wet clutch control method.

[0169] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0170] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0171] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A control method for a vehicle wet clutch, characterized in that, Includes the following steps: Collect feature data of the wet clutch at multiple moments, and extract the first target pressure and the first actual pressure of the wet clutch at the current moment from the feature data; Based on the first target pressure and the first actual pressure, calculate the first demand pressure of the wet clutch at the current moment, and based on the first demand pressure, calculate the rate of change of the demand pressure of the wet clutch at the current moment. The first predicted virtual pressure of the wet clutch at the current moment is determined based on the first demand pressure and the rate of change of the demand pressure. Based on the first predicted virtual pressure and the first demand pressure, the target electronic control demand current of the electronic control actuator in the wet clutch at the current moment is determined, so as to control the operation of the wet clutch using the target electronic control demand current.

2. The method according to claim 1, characterized in that, The calculation of the first required pressure of the wet clutch at the current moment based on the first target pressure and the first actual pressure includes: Obtain the first electronic control demand pressure of the electronically controlled actuator at the previous moment, and extract the second target pressure and the second actual pressure of the wet clutch at the previous moment from the feature data; Based on the first target pressure and the second target pressure, calculate the pressure feedforward value of the first demand pressure; Based on the first target pressure and the first actual pressure, calculate the first pressure error value of the wet clutch at the current moment; The first demand pressure is calculated based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value.

3. The method according to claim 2, characterized in that, The calculation of the first demand pressure based on the first electronically controlled demand pressure, the pressure feedforward value, and the first pressure error value includes: Based on the first pressure error value, determine the first proportional gain value, integral gain value and first differential gain value required for calculating the first demand pressure at the current moment; Based on the second pressure error value of the wet clutch at the previous moment, determine the second proportional gain value and the second differential gain value of the previous moment required to calculate the first demand pressure; The first demand pressure is calculated based on the first electronically controlled demand pressure, the pressure feedforward value, the first pressure error value, the first proportional gain value, the integral gain value, the first differential gain value, the second proportional gain value, and the second differential gain value.

4. The method according to claim 2, characterized in that, The step of determining the first predicted virtual pressure of the wet clutch at the current moment based on the first demand pressure and the demand pressure change rate includes: Based on the second actual pressure, determine the second predicted virtual pressure of the wet clutch at the previous moment; Based on the demand pressure change rate, determine the pressure delay coefficient of the wet clutch at the current moment, and obtain the pressure delay correction coefficient of the wet clutch at the current moment. The first predicted virtual pressure is determined based on the first demand pressure, the second predicted virtual pressure, the pressure delay coefficient, and the pressure delay correction coefficient.

5. The method according to claim 4, characterized in that, Before determining the second predicted virtual pressure of the wet clutch at the previous moment based on the second actual pressure, the method further includes: Obtain the oil filling status indicator information of the wet clutch; When the oil filling status identification information meets the preset oil filling conditions, the second predicted virtual pressure is determined based on the oil filling status identification information and the second actual pressure.

6. The method according to claim 1, characterized in that, The step of determining the target electronic control demand current of the electronically controlled actuator in the wet clutch at the current moment based on the first predicted virtual pressure and the first demand pressure includes: Extract the current transmission oil temperature of the wet clutch from the feature data; Calculate the pressure difference between the first predicted virtual pressure and the first target pressure; Calculate the pressure compensation factor based on the pressure difference and the current transmission oil temperature; The target electronic control demand current is calculated based on the pressure difference, the pressure compensation factor, and the first demand pressure.

7. The method according to claim 6, characterized in that, The step of calculating the target electronic control demand current based on the pressure difference, the pressure compensation factor, and the first demand pressure includes: Based on the pressure difference and the pressure compensation factor, calculate the required pressure compensation value of the wet clutch at the current moment; Based on the demand pressure compensation value and the first demand pressure, the second electronic control demand pressure of the electronic control actuator at the current moment is determined; Based on the second electrical control demand pressure, the target electrical control demand current is determined.

8. The method according to claim 7, characterized in that, Determining the target electrical control demand current based on the second electrical control demand pressure includes: Obtain the first mapping relationship between the second electronic control demand pressure and the target electronic control demand current; Based on the first mapping relationship and the second electrical control demand pressure, the target electrical control demand current is determined.

9. The method according to claim 6, characterized in that, The calculation of the pressure compensation factor based on the pressure difference and the current transmission oil temperature includes: Obtain the second mapping relationship between the pressure difference, the current transmission oil temperature, and the pressure compensation factor; The pressure compensation factor is calculated based on the second mapping relationship, the pressure difference, and the current transmission oil temperature.

10. The method according to claim 1, characterized in that, The step of calculating the rate of change of the demand pressure of the wet clutch at the current moment based on the first demand pressure includes: Obtain the second required pressure of the wet clutch at the target time; Based on the first demand pressure and the second demand pressure, calculate the current demand pressure change value of the wet clutch; Based on the change in demand pressure, the rate of change in demand pressure is calculated.

11. A vehicle, characterized in that, The vehicle includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the vehicle wet clutch control method as described in any one of claims 1-10.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the control method for a vehicle wet clutch as described in any one of claims 1-10.

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