Automatic transmission clutch oil recharging control method and device, automatic transmission and vehicle

Abstract

The invention provides an automatic transmission clutch oil recharging control method and device, an automatic transmission and a vehicle. Belongs to the technical field of automobiles. The method comprises the steps that the actual oil drainage time of a clutch of the automatic transmission in the last gear shifting period is counted; detecting the oil path pressure of the oil inlet end of the clutch and the pressure in a piston cavity of the clutch in the previous gear shifting period, and determining the theoretical oil drainage time of the clutch in the previous gear shifting period based on the oil path pressure and the pressure in the piston cavity; if the actual oil drainage time in the previous gear shifting period is larger than or equal to the theoretical oil drainage time, the first pressure is adopted as the oil charging pressure of the clutch in the current gear shifting period; and if the actual oil drainage time in the previous gear shifting period is smaller than the theoretical oil drainage time, the basic oil charging pressure is adopted as the oil charging pressure. According to the method, the oil charging pressure under different working conditions can be accurately matched, engine rotating speed galloping caused by undercharging is prevented, and meanwhile gear shifting impact caused by overcharging is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automatic transmission control, in particular to an automatic transmission clutch refilling control method and device, an automatic transmission and a vehicle. BACKGROUND

[0002] In an automatic transmission equipped with a wet clutch, the engagement and disengagement of the clutch are precisely controlled through the oil filling and oil bleeding processes of the hydraulic system. The clutch is internally provided with a piston cavity and an associated oil passage. The TCU (Transmission Control Unit) drives the oil to flow into the piston cavity by controlling the oil filling pressure, pushes the piston to move axially against the action force of the return spring, and then drives the friction plate to contact and press against the steel plate to complete power transmission. When disengagement is required, the hydraulic system bleeds oil, and the piston is reset under the action of the return spring, and the friction plate and the steel plate are separated to cut off the power transmission. Among them, the precise regulation of the oil filling pressure directly affects the oil filling speed and filling amount, and is the core to ensure the smooth engagement of the clutch and the smooth power transmission. The existing clutch oil filling control method cannot match the actual oil filling demand under some working conditions, resulting in insufficient oil filling, so that the clutch friction plate cannot reach the KP point (half engagement point) in time to realize effective power transmission. This underfilling state can cause the engine speed to fly, which not only destroys the continuity of power transmission, but also causes shift shock, poor driving smoothness and other problems, seriously affecting the user's driving experience. SUMMARY

[0003] The present application provides an automatic transmission clutch refilling control method and device, an automatic transmission and a vehicle to solve the problem of engine speed flying caused by inaccurate automatic transmission clutch oil filling control.

[0004] In a first aspect, the present application provides an automatic transmission clutch refilling control method, comprising: statistically determining the actual oil bleeding time of the clutch of the automatic transmission in the last shift cycle; detecting the oil passage pressure of the oil inlet end of the clutch and the pressure in the piston cavity of the clutch in the last shift cycle, and determining the theoretical oil bleeding time of the clutch in the last shift cycle based on the oil passage pressure and the pressure in the piston cavity; if the actual oil bleeding time in the last shift cycle is greater than or equal to the theoretical oil bleeding time, the first pressure is used as the oil filling pressure of the clutch in the current shift cycle; If the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time, then the basic filling pressure is used as the filling pressure of the clutch in the current shift cycle; wherein, the basic filling pressure is the filling pressure corresponding to the friction plate reaching the half engagement point by filling only the piston chamber volume of the clutch. The first pressure is greater than the basic filling pressure.

[0005] This embodiment first determines the theoretical oil drain time by statistically analyzing the actual oil drain time of the previous shift cycle and combining it with the oil pressure at the inlet end and the piston chamber pressure. This allows for accurate judgment of the residual oil state in the oil circuit. If the actual oil drain time is greater than or equal to the theoretical oil drain time, it indicates that the oil circuit has been completely drained, requiring a higher filling pressure to fill the piston chamber and the total volume of the oil circuit. If the actual oil drain time is less than the theoretical oil drain time, it indicates that although the clutch piston chamber has been completely drained, there is residual oil in the oil circuit, and only filling the piston chamber is needed to meet the filling requirements. Therefore, this application matches a first pressure and a basic filling pressure for different residual states. The first pressure under the completely drained condition ensures that the oil quickly fills the total volume, preventing engine overspeed due to underfilling. The basic filling pressure under the oil-supplemented condition avoids shift shock caused by overfilling, balancing power transmission efficiency and driving smoothness. Moreover, this method does not require additional hardware costs; precise filling under all operating conditions can be achieved through logic optimization alone, significantly improving the control accuracy and reliability of the automatic transmission while ensuring the continuity of power transmission and effectively improving the user's driving experience.

[0006] In one possible implementation, determining the theoretical oil release time of the clutch in the previous shift cycle based on the oil circuit pressure and the piston chamber pressure includes: The oil discharge flow rate of the clutch per unit time is calculated based on the difference between the oil circuit pressure and the piston chamber pressure during the previous shift cycle. The theoretical oil drain time of the clutch in the previous shift cycle is calculated based on the sum of the piston chamber and oil passage volumes of the clutch and the oil drain flow rate.

[0007] As can be seen from the above embodiments, since the pressure difference, as the core driving force of oil flow, directly determines the oil discharge rate, the flow rate calculation based on this parameter can accurately reflect the oil discharge capacity of the oil circuit. Therefore, this embodiment calculates the oil discharge flow rate per unit time by the difference between the oil circuit pressure at the inlet and the piston chamber pressure, making full use of the pressure characteristics and fluid flow laws of the hydraulic system to ensure the accuracy of the oil discharge flow rate calculation. Then, the theoretical oil discharge time is calculated by combining the total volume of the clutch piston chamber and the oil circuit, making the theoretical oil discharge time an objective quantitative standard for judging whether the oil circuit has completely discharged oil, avoiding errors caused by subjective experience judgment, and ensuring that the comparison results between the actual oil discharge time and the theoretical oil discharge time are more reliable, thereby providing a precise premise for the subsequent selection of differentiated filling pressure.

[0008] In one possible implementation, calculating the clutch's oil discharge flow rate per unit time based on the difference between the oil circuit pressure and the piston chamber pressure during the previous shift cycle includes: Based on formula Calculate the oil discharge flow rate of the clutch per unit time; in, This indicates the oil discharge flow rate of the clutch per unit time. C Indicates the orifice coefficient. Indicates the effective opening area of ​​the oil passage. Indicates the density of the transmission fluid; This indicates the oil pressure during the previous shift cycle. This indicates the pressure inside the piston chamber during the previous shift cycle.

[0009] As can be seen from the above embodiments, this embodiment designs a formula for calculating the oil drain flow rate based on the basic principles of fluid mechanics and the system structural parameters of the clutch. It comprehensively considers four key parameters: orifice coefficient, effective opening area of ​​the oil passage, pressure difference, and transmission oil density. This formula can accurately output the oil drain flow rate under different operating conditions (such as different oil temperatures and pressure differences), avoiding flow calculation deviations caused by missing parameters. Simultaneously, the standardized calculation formula makes the calculation process of the oil drain flow rate repeatable and verifiable, effectively reducing the implementation difficulty and error rate of the control method, ensuring the accuracy of the theoretical oil drain time calculation, and thus making the judgment of the residual state of the oil passage more accurate. This provides a solid guarantee for the precise matching of differentiated filling pressures, ultimately achieving refined and reliable clutch filling control.

[0010] In one possible implementation, before using the baseline filling pressure as the clutch filling pressure for the current shift cycle if the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time, the method further includes: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures.

[0011] The above method can quickly determine the basic filling pressure corresponding to the current oil temperature by looking up a table, thereby improving the calculation efficiency of the automatic transmission clutch refill control method.

[0012] In one possible implementation, the process of obtaining the basic oil filling pressure set includes: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Divide the volume of the clutch piston chamber by the filling time to obtain the basic filling flow rate; Based on the basic oil filling flow rate, the oil circuit pressure at the clutch inlet end corresponding to different oil temperatures, and the pressure inside the clutch piston chamber, the oil filling pressure at the corresponding oil temperature is determined and used as the basic oil filling pressure; according to the basic oil filling pressure corresponding to different oil temperatures, the basic oil filling pressure set is generated.

[0013] As can be seen from the above embodiments, this embodiment first conducts calibration experiments at different oil temperatures, fully considering the influence of oil temperature on the filling process, so that the basic filling pressure corresponding to each oil temperature can adapt to the oil characteristics and filling requirements at that temperature, avoiding the problem of insufficient adaptability to all working conditions caused by single-temperature calibration. Secondly, the basic filling flow rate is calculated by dividing the piston chamber volume by the filling time, so that the flow rate parameter is directly linked to the actual filling requirements, ensuring that the filling flow rate can complete the piston chamber filling within the specified time. Based on the basic filling flow rate, the basic filling pressure for the corresponding oil temperature is determined, so that the basic filling pressure meets the filling speed requirements without overfilling due to excessive pressure. The final generated basic filling pressure set covers the optimal pressure parameters at different oil temperatures, providing data support for quickly and accurately retrieving the corresponding pressure during actual control, while improving the calibration accuracy and reliability of the entire refill control method.

[0014] In one possible implementation, before using the first pressure as the clutch filling pressure for the current shift cycle if the actual oil discharge time in the previous shift cycle is greater than or equal to the theoretical oil discharge time, the method further includes: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures. The pressure compensation value corresponding to the current oil temperature is determined based on the pressure compensation set; the pressure compensation set includes the correspondence between different oil temperatures and pressure compensation values. The first pressure is obtained by adding the base filling pressure corresponding to the current oil temperature to the pressure compensation value.

[0015] As can be seen from the above embodiments, this embodiment ensures that the basic part of the first pressure can adapt to the current oil characteristics by collecting the current oil temperature and matching the corresponding basic filling pressure, thus avoiding the influence of oil temperature on filling accuracy. Secondly, by superimposing the basic filling pressure and the pressure compensation value, the first pressure can accurately match the total volume filling requirements of the piston chamber and oil circuit. This ensures the rationality of the first pressure, avoids excessive pressure, and meets the filling requirements of the additional volume. It ensures that under the condition of complete oil discharge, the oil can fill the total volume within a specified time, allowing the friction plates to reach the semi-engagement point in time, effectively preventing engine overspeed caused by underfilling.

[0016] In one possible implementation, the process of obtaining the pressure compensation set includes: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Add the volume of the clutch piston chamber to the volume of the oil passage to obtain the maximum oil filling volume of the clutch, and divide the maximum oil filling volume of the clutch by the oil filling time to obtain the target oil filling flow rate; Based on the target oil filling flow rate, the oil circuit pressure at the clutch inlet at different oil temperatures, and the pressure inside the clutch piston chamber, the corresponding oil filling pressure is determined and used as the maximum oil filling pressure. Determine the base oil filling pressure corresponding to the current oil temperature based on the base oil filling pressure set; The pressure compensation value is obtained by subtracting the base filling pressure from the maximum filling pressure at the same oil temperature. The pressure compensation set is generated based on the pressure compensation values ​​corresponding to different oil temperatures.

[0017] As can be seen from the above embodiments, this embodiment derives the pressure compensation value by the difference between the maximum filling pressure and the basic filling pressure, so that the pressure compensation value can accurately reflect the pressure difference between total volume filling and piston chamber filling only, ensuring that the first pressure after compensation can accurately match the total volume filling requirements. The final generated pressure compensation set covers the optimal compensation parameters under different oil temperatures, providing reliable data support for the calculation of the first pressure, making the filling pressure calibration under the complete oil drain condition more accurate, and further improving the accuracy and feasibility of the entire refill control method.

[0018] Secondly, this application provides an automatic transmission clutch refill control device, comprising: The actual oil draining time acquisition module is used to calculate the actual oil draining time of the clutch in the previous shift cycle of the automatic transmission. The theoretical oil drain time calculation module is used to detect the oil circuit pressure at the oil inlet of the clutch and the pressure inside the piston chamber of the clutch in the previous shift cycle, and to determine the theoretical oil drain time of the clutch in the previous shift cycle based on the oil circuit pressure and the pressure inside the piston chamber. The first oil filling module is used to use the first pressure as the oil filling pressure of the clutch in the current shift cycle if the actual oil discharge time in the previous shift cycle is greater than or equal to the theoretical oil discharge time. The basic filling module is used to use the basic filling pressure as the filling pressure of the clutch in the current shift cycle if the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time; wherein, the basic filling pressure is the filling pressure corresponding to the friction plate reaching the half engagement point by filling the piston chamber volume of the clutch only. The first pressure is greater than the basic filling pressure.

[0019] In one possible implementation, the theoretical drain time calculation module includes: The oil drain flow calculation unit is used to calculate the oil drain flow of the clutch per unit time based on the difference between the oil circuit pressure and the piston chamber pressure in the previous shift cycle. The theoretical oil drain time calculation unit is used to calculate the theoretical oil drain time of the clutch in the previous shift cycle based on the sum of the volumes of the piston chamber and the oil passage of the clutch, and the oil drain flow rate.

[0020] In one possible implementation, the oil drain flow calculation unit includes: Based on formula Calculate the oil discharge flow rate of the clutch per unit time; in, This indicates the oil discharge flow rate of the clutch per unit time. C Indicates the orifice coefficient. Indicates the effective opening area of ​​the oil passage. Indicates the density of the transmission fluid; This indicates the oil pressure during the previous shift cycle. This indicates the pressure inside the piston chamber during the previous shift cycle.

[0021] In one possible implementation, the automatic transmission clutch refill control device further includes a base fill pressure acquisition module for: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures.

[0022] In one possible implementation, the automatic transmission clutch refill control device further includes a basic refill pressure set acquisition module, used for: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Divide the volume of the clutch piston chamber by the filling time to obtain the basic filling flow rate; Based on the basic oil filling flow rate, the oil circuit pressure at the clutch inlet end corresponding to different oil temperatures, and the pressure inside the clutch piston chamber, the oil filling pressure at the corresponding oil temperature is determined and used as the basic oil filling pressure; according to the basic oil filling pressure corresponding to different oil temperatures, the basic oil filling pressure set is generated.

[0023] In one possible implementation, the automatic transmission clutch refill control device further includes a first pressure acquisition module for: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures. The pressure compensation value corresponding to the current oil temperature is determined based on the pressure compensation set; the pressure compensation set includes the correspondence between different oil temperatures and pressure compensation values. The first pressure is obtained by adding the base filling pressure corresponding to the current oil temperature to the pressure compensation value.

[0024] In one possible implementation, the automatic transmission clutch refill control device further includes a pressure compensation set acquisition module, used for: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Add the volume of the clutch piston chamber to the volume of the oil passage to obtain the maximum oil filling volume of the clutch, and divide the maximum oil filling volume of the clutch by the oil filling time to obtain the target oil filling flow rate; Based on the target oil filling flow rate, the oil circuit pressure at the clutch inlet at different oil temperatures, and the pressure inside the clutch piston chamber, the corresponding oil filling pressure is determined and used as the maximum oil filling pressure. Determine the base oil filling pressure corresponding to the current oil temperature based on the base oil filling pressure set; The pressure compensation value is obtained by subtracting the base filling pressure from the maximum filling pressure at the same oil temperature. The pressure compensation set is generated based on the pressure compensation values ​​corresponding to different oil temperatures.

[0025] Thirdly, this application provides an automatic transmission, including a controller, the controller including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the automatic transmission clutch refill control method as described in the possible implementation of the first aspect above.

[0026] Fourthly, embodiments of this application provide a vehicle including the automatic transmission described in the third aspect above. Attached Figure Description

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

[0028] Figure 1 This is an application scenario diagram of the automatic transmission clutch refill control method provided in the embodiments of this application; Figure 2 This is a schematic diagram of the automatic transmission clutch refill control device provided in the embodiments of this application; Figure 3 This is a schematic diagram of an automatic transmission provided in an embodiment of this application. Detailed Implementation

[0029] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0031] In automatic transmissions equipped with wet clutches, the clutch integrates a sealed piston chamber formed by the inner wall of the clutch drum, the piston end face, and a sealing ring. This piston chamber is connected to the hydraulic control module via a pre-set oil circuit, forming a complete hydraulic transmission path. The TCU, as the control core, dynamically outputs oil filling pressure control commands based on operating parameters such as engine load, vehicle speed, and current gear. When power engagement is required, the TCU controls the hydraulic valve to open, connecting the clutch inlet to the high-pressure oil source. High-pressure oil is injected into the piston chamber along the oil circuit. The hydraulic force generated by the oil pushes the piston to overcome the preload of the return spring, causing it to move axially. This drives the friction plates closer to the steel plates and gradually presses them together. As the pressure increases, the positive pressure between the friction plates and the steel plates increases, gradually improving the torque transmission capability and ultimately achieving stable power transmission. When power disengagement is required, the TCU controls the hydraulic valve to close and opens the drain channel. At this time, the clutch inlet is no longer connected to the high-pressure oil source but instead forms a passage with the oil pan through the drain valve and return channel. The oil inside the piston chamber is discharged along the drain circuit, the hydraulic force disappears, and the piston returns to its original position under the elastic restoring force of the return spring. The friction plates separate from the steel plates, and the power transmission path is cut off. In this process, the precision of the filling pressure control is crucial. The magnitude of the filling pressure directly determines the filling speed of the oil into the piston chamber. The matching degree between the filling speed and the filling amount directly affects the contact timing, clamping force, and pressure rise gradient between the friction plates and the steel plates. Its control precision is directly related to the control quality of the entire automatic transmission. However, existing clutch filling control methods generally adopt a design approach of fixed pressure calibration or single-condition adaptation, failing to fully consider the differences in the residual state of the clutch oil circuit during actual operation. This results in a serious lack of adaptability between the filling pressure and actual operating conditions. Specifically, from a practical perspective, if the vehicle has not been driven for a long time and there is no oil in the oil passages, insufficient filling can easily occur when starting the vehicle and shifting gears, leading to underfilling of the clutch and causing the engine to run at high speed, affecting the driving experience. On the other hand, during vehicle operation, due to gear shifting, the clutch A currently engaged in gear becomes the disengaged clutch A, requiring the oil passages to be unloaded and clutch A to disengage. However, if the oil in the clutch passages is not completely unloaded, clutch A may become the gearing clutch again. In this case, clutch A needs to be filled with oil. Because there is still some unloaded oil in clutch A, if the clutch is still requested to close as if it were completely empty, overfilling of clutch A will occur, causing the engine speed to be dragged down, affecting the driving experience.

[0032] Existing control methods do not accurately identify and adapt to the different oil retention conditions mentioned above. Instead, they calibrate a fixed filling pressure based on the ideal condition of a completely empty piston chamber. When there is a lot of residual oil in the oil circuit, the actual effective volume required for filling decreases, and the fixed filling pressure will lead to overfilling, causing overfilling. Conversely, when there is little residual oil or the oil circuit is completely empty, the actual effective volume required for filling increases, and the existing calibrated filling pressure cannot meet the volume requirement, resulting in underfilling. Among these, underfilling is the core issue affecting driving experience. Insufficient filling pressure prevents the piston chamber from reaching the hydraulic pressure required to push the friction plate to the KP point within a preset time. The friction plate and steel plate fail to make timely contact and transmit torque. At this time, the power output of the engine cannot be effectively transmitted to the transmission through the clutch, causing the engine to operate in a no-load or low-load state, which in turn leads to engine overspeed. This phenomenon not only disrupts the continuity of power transmission, causing power interruption and sudden speed changes during gear shifts, but also triggers significant shift shocks, reducing driving smoothness. At the same time, speed overruns and shocks exacerbate abnormal wear on the clutch friction plates, shortening the clutch's service life.

[0033] Based on the above problems, this embodiment provides an automatic transmission clutch refill control method. This method monitors the actual oil drain time and theoretical oil drain time of the previous shift cycle to determine whether there is any un-drained oil in the oil circuit in the previous shift cycle. If there is, the basic refill pressure corresponding to the scenario where only the piston chamber drains oil is used. If there is no oil in the oil circuit in the previous shift cycle, the maximum first pressure is used for refilling, thereby avoiding the phenomenon of speed runaway caused by underfilling of the clutch.

[0034] For details, see Figure 1 The document illustrates a flowchart of the automatic transmission clutch refill control method provided in this embodiment. This method is applied to the TCU of a vehicle and is described in detail below: S101: Statistics on the actual oil leakage time of the clutch in the previous shift cycle of the automatic transmission.

[0035] This embodiment is applied to the Nth shift cycle after the vehicle is powered on, and N>1. In the first shift cycle after the vehicle is powered on, the TCU assumes that there is no oil in the piston chamber and oil passage of the clutch. The maximum pressure (first pressure) that can fill the piston chamber and oil passage is used as the filling pressure to control the clutch filling, so as to avoid the phenomenon of speed runaway caused by insufficient filling pressure due to the absence of any oil in the oil passage when the vehicle has not been started for a long time.

[0036] In this embodiment, when the clutch needs to disengage (such as during gear shifting or power cut-off), the TCU sends an oil release command to the hydraulic control module, controlling the oil release valve to open and the oil filling valve to close. At this time, the oil circuit begins to depressurize, and the timing module starts simultaneously. When the clutch piston chamber pressure drops below the preset oil release completion threshold for M consecutive cycles, the oil release is complete, and the timing module stops timing. The timing duration is the actual oil release time. The value of M can range from 2 to 5.

[0037] The preset oil discharge completion threshold is the maximum pressure value at which the piston chamber pressure is insufficient to push the piston and completely separate the friction plate from the steel plate.

[0038] S102: Detect the oil pressure at the inlet of the clutch and the pressure inside the piston chamber of the clutch during the previous shift cycle, and determine the theoretical oil discharge time of the clutch during the previous shift cycle based on the oil pressure and the pressure inside the piston chamber.

[0039] In this embodiment, a pressure sensor is installed at the inlet end of the clutch oil circuit to detect the oil pressure at the clutch inlet end in real time. A pressure sensor is also installed inside the clutch piston chamber to collect the pressure within the piston chamber in real time. During the oil draining phase of the previous shift cycle, the oil pressure at the inlet end and the pressure inside the clutch piston chamber are detected. The pressure difference driving the oil flow during the clutch draining phase is then determined by calculating the difference between the oil pressure at the clutch inlet end and the pressure inside the clutch piston chamber. Based on fluid mechanics principles, the oil draining flow rate is calculated based on this pressure difference, and the theoretical oil draining time for the previous shift cycle is calculated based on the oil draining flow rate. This theoretical oil draining time is the theoretical time required for the oil circuit and piston chamber to be completely emptied of oil, and it serves as the benchmark for determining whether the oil circuit has completely drained.

[0040] S103: If the actual oil drain time in the previous shift cycle is greater than or equal to the theoretical oil drain time, then the first pressure is used as the oil filling pressure of the clutch in the current shift cycle.

[0041] S104: If the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time, then the basic filling pressure is used as the filling pressure of the clutch in the current shift cycle; wherein, the basic filling pressure is the filling pressure corresponding to the friction plate reaching the half engagement point by only filling the piston chamber volume of the clutch; the first pressure is greater than the basic filling pressure.

[0042] Specifically, the base filling pressure is the pressure that fills only the clutch piston chamber volume, allowing the friction plates to reach point KP, suitable for oil-storage conditions. Point KP is the point where the friction plates first contact the steel plate and transmit a small torque. The first pressure is a filling pressure greater than the base filling pressure, requiring simultaneous filling of both the piston chamber and the total oil circuit volume, suitable for conditions where the oil circuit is completely drained.

[0043] Since the theoretical oil drain time is the theoretical time required for the oil passage and piston chamber to be completely emptied of oil, if the actual oil drain time in the previous shift cycle is less than the theoretical oil drain time, it means that the oil passage was not completely emptied in the previous shift cycle and there is still oil remaining. Therefore, the basic filling pressure can be used to fill the clutch with oil in the current shift cycle to avoid excessive filling of oil, which would drag the engine speed and affect the driving experience.

[0044] When the actual oil drain time in the previous shift cycle is greater than or equal to the theoretical oil drain time, it means that the oil passage was completely emptied in the previous shift cycle and there was no oil left. Therefore, the first pressure can be used to fill the clutch with oil in the current shift cycle to avoid insufficient oil filling, which would lead to underfilling of the clutch and cause the engine speed to run away, affecting the driving experience.

[0045] As can be seen from the above embodiments, this embodiment first determines the theoretical oil drain time by statistically analyzing the actual oil drain time of the previous shift cycle and combining it with the oil pressure at the inlet end of the oil circuit and the piston chamber pressure. This allows for an accurate assessment of the residual oil state in the oil circuit. If the actual oil drain time is greater than or equal to the theoretical oil drain time, it indicates that the oil circuit has completely drained, and a greater filling pressure is needed to fill the piston chamber and the total volume of the oil circuit. If the actual oil drain time is less than the theoretical oil drain time, it indicates that although the clutch piston chamber has completely drained, there is residual oil in the oil circuit, and only filling the piston chamber is needed to meet the filling requirements. Therefore, this application matches a first pressure and a basic filling pressure for different residual states. The first pressure under the condition of complete oil drain ensures that the oil quickly fills the total volume, preventing engine overspeed caused by underfilling. The basic filling pressure under the condition of oil storage avoids shift shock caused by overfilling, balancing power transmission efficiency and driving smoothness. Moreover, this method does not require additional hardware costs and can achieve accurate oil filling under all working conditions through logic optimization alone, significantly improving the control accuracy and reliability of the automatic transmission, while ensuring the continuity of power transmission and effectively improving the user's driving experience.

[0046] In one possible implementation, the specific implementation process of S102 includes: S201: Calculate the oil discharge flow rate of the clutch per unit time based on the difference between the oil circuit pressure and the piston chamber pressure in the previous shift cycle; S202: Calculate the theoretical oil discharge time of the clutch in the previous shift cycle based on the sum of the piston chamber and oil passage volumes of the clutch and the oil discharge flow rate.

[0047] In this implementation, the oil drain flow rate refers to the volume of oil discharged from the clutch oil passage per unit time during the oil draining phase. The maximum volume of the oil passage is the sum of the clutch piston chamber volume and the connected oil passage volume, which is the total volume of oil that needs to be emptied for complete oil draining.

[0048] When calculating the oil drain flow rate, the controller can determine the corresponding oil drain flow rate under the pressure difference of the previous shift cycle based on the quantitative relationship table between the pressure difference and the oil drain flow rate per unit time determined by previous experiments. After calculating the clutch oil drain flow rate per unit time, the controller can divide the sum of the piston chamber and oil passage volumes by the oil drain flow rate per unit time to obtain the theoretical oil drain time of the clutch in the previous shift cycle.

[0049] As can be seen from the above embodiments, since the pressure difference, as the core driving force of oil flow, directly determines the oil discharge rate, the flow rate calculation based on this parameter can accurately reflect the oil discharge capacity of the oil circuit. Therefore, this embodiment calculates the oil discharge flow rate per unit time by the difference between the oil circuit pressure at the inlet and the piston chamber pressure, making full use of the pressure characteristics and fluid flow laws of the hydraulic system to ensure the accuracy of the oil discharge flow rate calculation. Then, the theoretical oil discharge time is calculated by combining the total volume of the clutch piston chamber and the oil circuit, making the theoretical oil discharge time an objective quantitative standard for judging whether the oil circuit has completely discharged oil, avoiding errors caused by subjective experience judgment, and ensuring that the comparison results between the actual oil discharge time and the theoretical oil discharge time are more reliable, thereby providing a precise premise for the subsequent selection of differentiated filling pressure.

[0050] In one possible implementation, the specific implementation process of S201 includes: Based on formula Calculate the oil discharge flow rate of the clutch per unit time; in, This indicates the oil discharge flow rate of the clutch per unit time. C Indicates the orifice coefficient. Indicates the effective opening area of ​​the oil passage. Indicates the density of the transmission fluid; This indicates the oil pressure during the previous shift cycle. This indicates the pressure inside the piston chamber during the previous shift cycle.

[0051] In this embodiment, the orifice coefficient is a dimensionless parameter reflecting the flow characteristics of the oil drain orifice, and its value can range from 0.6 to 0.9. The effective opening area of ​​the oil circuit is the cross-sectional area through which the oil actually flows in the drain channel. The orifice coefficient and the effective opening area reflect the structural characteristics of the oil circuit. The transmission fluid density is the mass-to-volume ratio of the transmission fluid under current operating conditions. This value varies with oil temperature and oil parameters, reflecting the physical properties of the oil.

[0052] P1-P2 is the oil filling control pressure, which is the actual pressure difference between the oil inlet pressure and the piston chamber, and is the power source for oil flow.

[0053] Specifically, the orifice coefficient and the effective opening area of ​​the oil passage are factory parameters of the system. While collecting the oil passage pressure and piston chamber pressure from the previous shift cycle, the controller also needs to determine the transmission fluid density corresponding to the oil temperature in the previous shift cycle based on the oil temperature-density relationship table. Then, the oil passage pressure, piston chamber pressure, and transmission fluid density corresponding to the oil temperature in the previous shift cycle are input into the above formula to obtain the clutch oil discharge flow rate per unit time.

[0054] In one possible implementation, to improve the accuracy of the oil drain flow calculation, this embodiment can obtain a correction value based on the service life of the clutch after obtaining the factory orifice coefficient. Then, the orifice coefficient is multiplied by the correction value to obtain the current orifice coefficient. The service life is negatively correlated with the correction value, and the correction value can range from 0.3 to 1.

[0055] As can be seen from the above embodiments, this embodiment designs a formula for calculating the oil drain flow rate based on the basic principles of fluid mechanics and the system structural parameters of the clutch. It comprehensively considers four key parameters: orifice coefficient, effective opening area of ​​the oil passage, pressure difference, and transmission oil density. This formula can accurately output the oil drain flow rate under different operating conditions (such as different oil temperatures and pressure differences), avoiding flow calculation deviations caused by missing parameters. Simultaneously, the standardized calculation formula makes the calculation process of the oil drain flow rate repeatable and verifiable, effectively reducing the implementation difficulty and error rate of the control method, ensuring the accuracy of the theoretical oil drain time calculation, and thus making the judgment of the residual state of the oil passage more accurate. This provides a solid guarantee for the precise matching of differentiated filling pressures, ultimately achieving refined and reliable clutch filling control.

[0056] In one possible implementation, prior to S104, the method provided in this embodiment further includes: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures.

[0057] In this embodiment, the basic filling pressure set is a dataset of the correspondence between oil temperature and basic filling pressure established in advance through calibration experiments, stored in the TCU, and covers all the matching pressure values ​​in the clutch operating temperature range.

[0058] In this embodiment, a temperature sensor can be installed inside the piston chamber of the clutch to determine the current oil temperature within the clutch piston chamber. Since the viscosity of the oil varies at different temperatures, its flow characteristics also differ. At low temperatures, the oil viscosity is high, requiring higher pressure to drive the oil flow; at high temperatures, the oil viscosity is low, requiring only lower pressure to drive the oil flow. Therefore, this embodiment determines the corresponding base filling pressure by detecting the real-time oil temperature.

[0059] In one possible implementation, the process of obtaining the basic oil filling pressure set includes: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Divide the volume of the clutch piston chamber by the filling time to obtain the basic filling flow rate; Based on the basic oil filling flow rate, the oil circuit pressure at the clutch inlet end at different oil temperatures, and the pressure inside the clutch piston chamber, the oil filling pressure at the corresponding oil temperature is determined and used as the basic oil filling pressure. The basic filling pressure set is generated based on the basic filling pressure corresponding to different oil temperatures.

[0060] In this embodiment, the basic filling flow rate is the volume of oil required per unit time to fill the piston chamber at a specific oil temperature, that is, the ratio of the piston chamber volume to the basic filling time.

[0061] Specifically, when the actual oil discharge time of the clutch does not reach the theoretical oil discharge time, it is assumed that there is oil in the clutch oil supply circuit; under this condition, clutch filling only needs to consider the clutch piston chamber volume. Since the clutch filling time Time is fixed (a fixed value set according to the vehicle performance requirements) and the clutch piston chamber volume V0 is fixed, the change in clutch filling flow rate ΔQ0 = V0 / Time. Then, the transmission oil density at this oil temperature, the oil circuit pressure at the clutch inlet during the oil discharge process, and the pressure inside the clutch piston chamber are determined. Based on the above clutch oil discharge flow rate calculation formula, the clutch filling pressure value P11 at this oil temperature (i.e., P1-P2 in the formula) can be determined. This pressure value is the basic filling pressure. By calibrating the basic filling pressure at different oil temperatures, the basic filling pressure set at different oil temperatures is finally obtained.

[0062] In this embodiment, after obtaining the basic filling pressure corresponding to multiple oil temperatures, the basic filling pressure corresponding to the intermediate oil temperature that was not detected can be interpolated based on the basic filling pressure measured at adjacent oil temperatures. This allows the basic filling pressure set to accurately match the oil flow characteristics and operating condition differences, improving the adaptation accuracy of the basic filling pressure from the data source and providing core data support for the reliability and smoothness of subsequent clutch refill control.

[0063] In this embodiment, to more accurately calculate the basic filling pressure value, the basic filling time under each oil temperature condition can be statistically analyzed in real time as the filling time Time in the above calculation process. Specifically, under different oil temperature conditions, the filling time required to fill only the clutch piston chamber volume to bring the friction plate to the semi-engagement point is statistically analyzed and used as the basic filling time Time.

[0064] As can be seen from the above embodiments, this embodiment first conducts calibration experiments at different oil temperatures, fully considering the influence of oil temperature on the filling process, so that the basic filling pressure corresponding to each oil temperature can adapt to the oil characteristics and filling requirements at that temperature, avoiding the problem of insufficient adaptability to all working conditions caused by single-temperature calibration. Secondly, the basic filling flow rate is calculated by dividing the piston chamber volume by the filling time, so that the flow rate parameter is directly linked to the actual filling requirements, ensuring that the filling flow rate can complete the piston chamber filling within the specified time. Based on the basic filling flow rate, the basic filling pressure for the corresponding oil temperature is determined, so that the basic filling pressure meets the filling speed requirements without overfilling due to excessive pressure. The final generated basic filling pressure set covers the optimal pressure parameters at different oil temperatures, providing data support for quickly and accurately retrieving the corresponding pressure during actual control, while improving the calibration accuracy and reliability of the entire refill control method.

[0065] In one possible implementation, prior to S103, the method provided in this embodiment further includes: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures. The pressure compensation value corresponding to the current oil temperature is determined based on the pressure compensation set; the pressure compensation set includes the correspondence between different oil temperatures and pressure compensation values. The first pressure is obtained by adding the base filling pressure corresponding to the current oil temperature to the pressure compensation value.

[0066] In this embodiment, the pressure compensation set is a pre-calibrated dataset showing the correspondence between oil temperature and pressure compensation values, stored in the TCU. The pressure compensation value is the additional pressure required to fill the oil passage volume under complete oil draining conditions; it is the difference between the first pressure and the base filling pressure, used to overcome the flow resistance and volume requirements for filling the oil passage volume, ensuring sufficient total volume filling. The first pressure represents the superposition of the base filling pressure and the pressure compensation value, adapted to the total volume filling requirements when the oil passage is completely drained.

[0067] This embodiment collects the current oil temperature and matches it with the corresponding basic filling pressure to ensure that the basic part of the first pressure can adapt to the current oil characteristics, thus avoiding the influence of oil temperature on filling accuracy. Secondly, a pressure compensation set and pressure compensation value are introduced to specifically address the need for additional oil circuit volume filling under complete oil drain conditions. When the actual oil drain time is greater than or equal to the theoretical oil drain time, the oil circuit has been completely drained. The filling process needs to fill both the piston chamber and the oil circuit volume simultaneously. Compared to the scenario of only filling the piston chamber, a greater filling pressure is required to overcome the additional oil circuit flow resistance and volume requirements. Therefore, a pressure compensation value is introduced. By superimposing the base filling pressure and the pressure compensation value, the first pressure can accurately match the total volume filling requirements of the piston chamber and the oil circuit. This ensures the rationality of the first pressure, avoids excessive pressure, and meets the filling requirements of the additional volume. It ensures that under complete oil drain conditions, the oil can fill the total volume within a specified time, allowing the friction plates to reach the semi-engagement point in time. This effectively prevents engine speed runaway caused by under-filling and avoids power shock caused by over-filling, thus balancing the timeliness and smoothness of power transmission.

[0068] In one possible implementation, the process of obtaining the pressure compensation set includes: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Add the volume of the clutch piston chamber to the volume of the oil passage to obtain the maximum oil filling volume of the clutch, and divide the maximum oil filling volume of the clutch by the oil filling time to obtain the target oil filling flow rate; Based on the target oil filling flow rate, the oil circuit pressure at the clutch inlet at different oil temperatures, and the pressure inside the clutch piston chamber, the corresponding oil filling pressure is determined and used as the maximum oil filling pressure. Determine the base oil filling pressure corresponding to the current oil temperature based on the base oil filling pressure set; The pressure compensation value is obtained by subtracting the base filling pressure from the maximum filling pressure at the same oil temperature. The pressure compensation set is generated based on the pressure compensation values ​​corresponding to different oil temperatures.

[0069] In this embodiment, when the clutch oil discharge time exceeds or equals the theoretical oil discharge time, the clutch oil circuit is considered to be completely discharged. Under this condition, the clutch oil filling volume is obtained by summing the clutch oil circuit volume V1 and the clutch piston chamber volume V0. Since the clutch oil filling time Time is fixed and the maximum oil filling volume V is fixed, the clutch oil filling flow rate change ΔQ1 = V / Time. The clutch oil filling pressure P12 is obtained using the clutch oil discharge flow rate calculation formula. By calibrating the operating conditions at different oil temperatures, the maximum oil filling pressure dataset under these conditions is obtained.

[0070] By using the maximum filling pressure dataset and the basic filling pressure dataset corresponding to the two operating conditions, the pressure compensation value ΔP = P12 – P11 corresponding to the same oil temperature is obtained, and then the correspondence between the pressure compensation value and the pressure compensation value at different temperatures is obtained, thus obtaining the pressure compensation dataset.

[0071] In this embodiment, after obtaining the pressure compensation values ​​corresponding to multiple oil temperatures, the pressure compensation values ​​corresponding to the intermediate undetected oil temperatures can be interpolated based on the pressure compensation values ​​obtained from adjacent oil temperature measurements. This allows the pressure compensation set to accurately match the oil flow characteristics and operating condition differences, improving the adaptation accuracy of the first pressure from the data source and providing core data support for the reliability and smoothness of subsequent clutch refill control.

[0072] In this embodiment, to more accurately calculate the maximum filling pressure, the maximum filling time under each oil temperature condition can be statistically analyzed in real time as the filling time (Time) in the above calculation process. Specifically, under different oil temperature conditions, the filling time required to fully fill the clutch piston chamber volume and oil passage volume so that the friction plate reaches the semi-engagement point is statistically analyzed and used as the maximum filling time (Time). Then, the target filling flow rate is calculated based on this maximum filling time.

[0073] As can be seen from the above embodiments, this embodiment derives the pressure compensation value by the difference between the maximum filling pressure and the basic filling pressure, so that the pressure compensation value can accurately reflect the pressure difference between total volume filling and piston chamber filling only, ensuring that the first pressure after compensation can accurately match the total volume filling requirements. The final generated pressure compensation set covers the optimal compensation parameters under different oil temperatures, providing reliable data support for the calculation of the first pressure, making the filling pressure calibration under the complete oil drain condition more accurate, and further improving the accuracy and feasibility of the entire refill control method.

[0074] In one possible implementation, if the actual oil drain time in the previous shift cycle is greater than or equal to the theoretical oil drain time, the difference between the actual oil drain time and the theoretical oil drain time can be calculated, and the time difference can be divided by the oil circuit drain time to obtain the time ratio. Finally, the pressure compensation value determined based on the current oil temperature based on the pressure compensation value is multiplied by the time ratio to obtain the updated pressure compensation value.

[0075] The above method can ensure that, when there is oil in the oil circuit, the pressure compensation value can be determined more accurately based on the amount of oil in the oil circuit, thereby further improving the accuracy of the filling pressure and avoiding overfilling and underfilling.

[0076] This embodiment utilizes a precise physical model of the clutch and a software timer combination to estimate the oil quantity status of the clutch's working oil circuit. Based on the oil quantity status of the clutch's working oil circuit, it achieves precise control of clutch refilling. Furthermore, this embodiment abandons the traditional clutch pressure-holding design approach, reducing the electrical energy loss caused by clutch pressure holding while providing the desired oil filling effect; thus saving clutch energy consumption.

[0077] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0078] The following are device embodiments of this application. For details not described in detail, please refer to the corresponding method embodiments described above.

[0079] Figure 2 A schematic diagram of the automatic transmission clutch refill control device provided in an embodiment of this application is shown. For ease of explanation, only the parts related to the embodiment of this application are shown, and are described in detail below: like Figure 2 As shown, the automatic transmission clutch refill control device 100 includes: The actual oil draining time acquisition module 110 is used to calculate the actual oil draining time of the clutch in the previous shift cycle of the automatic transmission. The theoretical oil drain time calculation module 120 is used to detect the oil circuit pressure at the oil inlet of the clutch and the piston chamber pressure of the clutch in the previous shift cycle, and to determine the theoretical oil drain time of the clutch in the previous shift cycle based on the oil circuit pressure and the piston chamber pressure. The first oil filling module 130 is used to use the first pressure as the oil filling pressure of the clutch in the current shift cycle if the actual oil discharge time in the previous shift cycle is greater than or equal to the theoretical oil discharge time. The basic filling module 140 is used to use the basic filling pressure as the filling pressure of the clutch in the current shift cycle if the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time; wherein, the basic filling pressure is the filling pressure corresponding to the friction plate reaching the half engagement point by filling the piston chamber volume of the clutch only. The first pressure is greater than the basic filling pressure.

[0080] In one possible implementation, the theoretical draining time calculation module 120 includes: The oil drain flow calculation unit is used to calculate the oil drain flow of the clutch per unit time based on the difference between the oil circuit pressure and the piston chamber pressure in the previous shift cycle. The theoretical oil drain time calculation unit is used to calculate the theoretical oil drain time of the clutch in the previous shift cycle based on the sum of the volumes of the piston chamber and the oil passage of the clutch, and the oil drain flow rate.

[0081] In one possible implementation, the oil drain flow calculation unit includes: Based on formula Calculate the oil discharge flow rate of the clutch per unit time; in, This indicates the oil discharge flow rate of the clutch per unit time. C Indicates the orifice coefficient. Indicates the effective opening area of ​​the oil passage. Indicates the density of the transmission fluid; This indicates the oil pressure during the previous shift cycle. This indicates the pressure inside the piston chamber during the previous shift cycle.

[0082] In one possible implementation, the automatic transmission clutch refill control device 100 further includes a basic refill pressure acquisition module for: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures.

[0083] In one possible implementation, the automatic transmission clutch refill control device further includes a basic refill pressure set acquisition module, used for: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Divide the volume of the clutch piston chamber by the filling time to obtain the basic filling flow rate; Based on the basic oil filling flow rate, the oil circuit pressure at the clutch inlet end corresponding to different oil temperatures, and the pressure inside the clutch piston chamber, the oil filling pressure at the corresponding oil temperature is determined and used as the basic oil filling pressure; according to the basic oil filling pressure corresponding to different oil temperatures, the basic oil filling pressure set is generated.

[0084] In one possible implementation, the automatic transmission clutch refill control device 100 further includes a first pressure acquisition module for: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures. The pressure compensation value corresponding to the current oil temperature is determined based on the pressure compensation set; the pressure compensation set includes the correspondence between different oil temperatures and pressure compensation values. The first pressure is obtained by adding the base filling pressure corresponding to the current oil temperature to the pressure compensation value.

[0085] In one possible implementation, the automatic transmission clutch refill control device further includes a pressure compensation set acquisition module, used for: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Add the volume of the clutch piston chamber to the volume of the oil passage to obtain the maximum oil filling volume of the clutch, and divide the maximum oil filling volume of the clutch by the oil filling time to obtain the target oil filling flow rate; Based on the target oil filling flow rate, the oil circuit pressure at the clutch inlet at different oil temperatures, and the pressure inside the clutch piston chamber, the corresponding oil filling pressure is determined and used as the maximum oil filling pressure. Determine the base oil filling pressure corresponding to the current oil temperature based on the base oil filling pressure set; The pressure compensation value is obtained by subtracting the base filling pressure from the maximum filling pressure at the same oil temperature. The pressure compensation set is generated based on the pressure compensation values ​​corresponding to different oil temperatures.

[0086] This application also provides a computer program product having program code that, when run in a corresponding processor, controller, computing device, or automatic transmission, executes the steps in any of the above-described embodiments of the automatic transmission clutch refill control method, for example... Figure 1 Steps S101 to S104 are shown. Those skilled in the art will understand that the methods and apparatus proposed in the embodiments of this application can be implemented in various forms, including hardware, software, firmware, dedicated processors, or combinations thereof. Dedicated processors may include application-specific integrated circuits (ASICs), reduced instruction set computers (RISCs), and / or field-programmable gate arrays (FPGAs). The proposed methods and apparatus are preferably implemented as a combination of hardware and software. The software is preferably installed as an application program on a program storage device. This is typically based on a machine with a computer platform, such as one or more central processing units (CPUs), random access memory (RAM), and one or more input / output (I / O) interfaces. An operating system is also typically installed on the computer platform. The various processes and functions described herein may be part of an application program, or a portion thereof may be executed by an operating system.

[0087] Figure 3 This is a schematic diagram of an automatic transmission provided in an embodiment of this application. Figure 3As shown, the automatic transmission 3 in this embodiment includes a processor 30, a memory 31, and a computer program 32 stored in the memory 31 and executable on the processor 30. When the processor 30 executes the computer program 32, it implements the steps in the various automatic transmission clutch refill control method embodiments described above, for example... Figure 1 Steps S101 to S104 are shown. Alternatively, when the processor 30 executes the computer program 32, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 2 The functions of modules 110 to 140 are shown.

[0088] For example, the computer program 32 may be divided into one or more modules / units, which are stored in the memory 31 and executed by the processor 30 to complete / implement the solution provided in this application. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program 32 in the automatic transmission 3.

[0089] The automatic transmission 3 can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The automatic transmission 3 may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art will understand that... Figure 3 This is merely an example of the automatic transmission 3 and does not constitute a limitation on the automatic transmission 3. It may include more or fewer components than shown, or combine certain components, or different components. For example, the automatic transmission may also include input / output devices, network access devices, buses, etc.

[0090] The processor 30 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0091] The memory 31 can be an internal storage unit of the automatic transmission 3, such as a hard drive or memory of the automatic transmission 3. The memory 31 can also be an external storage device of the automatic transmission 3, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the automatic transmission 3. Furthermore, the memory 31 can include both internal storage units and external storage devices of the automatic transmission 3. The memory 31 is used to store the computer program and other programs and data required by the automatic transmission. The memory 31 can also be used to temporarily store data that has been output or will be output.

[0092] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0093] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0094] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0095] In the embodiments provided in this application, it should be understood that the disclosed device / automatic transmission and method can be implemented in other ways. For example, the device / automatic transmission embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0096] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0097] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0098] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above-described embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various automatic transmission clutch refill control method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0099] Furthermore, the features of the embodiments shown in the accompanying drawings or the various embodiments mentioned in this specification should not be construed as independent embodiments. Rather, each feature described in one example of an embodiment can be combined with one or more other desired features from other embodiments to produce other embodiments not described in words or with reference to the accompanying drawings.

[0100] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for controlling the refilling of an automatic transmission clutch, characterized in that, include: The actual oil leakage time of the clutch in the automatic transmission during the previous shift cycle is statistically analyzed. The oil pressure at the clutch inlet and the piston chamber pressure of the clutch are detected during the previous shift cycle, and the theoretical oil discharge time of the clutch during the previous shift cycle is determined based on the oil pressure and the piston chamber pressure. If the actual oil drain time in the previous shift cycle is greater than or equal to the theoretical oil drain time, then the first pressure is used as the oil filling pressure of the clutch in the current shift cycle. If the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time, then the basic filling pressure is used as the filling pressure of the clutch in the current shift cycle; wherein, the basic filling pressure is the filling pressure corresponding to the friction plate reaching the half engagement point by filling only the piston chamber volume of the clutch. The first pressure is greater than the basic filling pressure.

2. The automatic transmission clutch refill control method according to claim 1, characterized in that, The determination of the theoretical oil release time of the clutch in the previous shift cycle based on the oil circuit pressure and the piston chamber pressure includes: The oil discharge flow rate of the clutch per unit time is calculated based on the difference between the oil circuit pressure and the piston chamber pressure during the previous shift cycle. The theoretical oil drain time of the clutch in the previous shift cycle is calculated based on the sum of the piston chamber and oil passage volumes of the clutch and the oil drain flow rate.

3. The automatic transmission clutch refill control method according to claim 2, characterized in that, The step of calculating the oil discharge flow rate of the clutch per unit time based on the difference between the oil circuit pressure and the piston chamber pressure during the previous shift cycle includes: Based on formula Calculate the oil discharge flow rate of the clutch per unit time; in, This indicates the oil discharge flow rate of the clutch per unit time. C Indicates the orifice coefficient. Indicates the effective opening area of ​​the oil passage. Indicates the density of the transmission fluid; This indicates the oil pressure during the previous shift cycle. This indicates the pressure inside the piston chamber during the previous shift cycle.

4. The automatic transmission clutch refill control method according to claim 1, characterized in that, Before using the baseline filling pressure as the clutch filling pressure for the current shift cycle, if the actual oil drain time in the previous shift cycle is less than the theoretical oil drain time, the method further includes: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures.

5. The automatic transmission clutch refill control method according to claim 4, characterized in that, The process of obtaining the basic oil filling pressure set includes: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Divide the volume of the clutch piston chamber by the filling time to obtain the basic filling flow rate; Based on the basic oil filling flow rate, the oil circuit pressure at the clutch inlet end corresponding to different oil temperatures, and the pressure inside the clutch piston chamber, the oil filling pressure at the corresponding oil temperature is determined and used as the basic oil filling pressure; according to the basic oil filling pressure corresponding to different oil temperatures, the basic oil filling pressure set is generated.

6. The automatic transmission clutch refill control method according to claim 1, characterized in that, Before using the first pressure as the clutch filling pressure for the current shift cycle if the actual oil drain time in the previous shift cycle is greater than or equal to the theoretical oil drain time, the method further includes: Collect the current oil temperature inside the clutch; The base filling pressure corresponding to the current oil temperature is determined based on the base filling pressure set; the base filling pressure set includes the correspondence between different oil temperatures and base filling pressures. The pressure compensation value corresponding to the current oil temperature is determined based on the pressure compensation set; the pressure compensation set includes the correspondence between different oil temperatures and pressure compensation values. The first pressure is obtained by adding the base filling pressure corresponding to the current oil temperature to the pressure compensation value.

7. The automatic transmission clutch refill control method according to claim 6, characterized in that, The process of obtaining the pressure compensation set includes: At different oil temperatures, the oil circuit pressure at the clutch inlet and the pressure inside the clutch piston chamber were collected respectively. Add the volume of the clutch piston chamber to the volume of the oil passage to obtain the maximum oil filling volume of the clutch, and divide the maximum oil filling volume of the clutch by the oil filling time to obtain the target oil filling flow rate; Based on the target oil filling flow rate, the oil circuit pressure at the clutch inlet at different oil temperatures, and the pressure inside the clutch piston chamber, the corresponding oil filling pressure is determined and used as the maximum oil filling pressure. Determine the base oil filling pressure corresponding to the current oil temperature based on the base oil filling pressure set; The pressure compensation value is obtained by subtracting the base filling pressure from the maximum filling pressure at the same oil temperature. The pressure compensation set is generated based on the pressure compensation values ​​corresponding to different oil temperatures.

8. An automatic transmission clutch refill control device, characterized in that, include: The actual oil draining time acquisition module is used to calculate the actual oil draining time of the clutch in the previous shift cycle of the automatic transmission. The theoretical oil drain time calculation module is used to detect the oil circuit pressure at the oil inlet of the clutch and the pressure inside the piston chamber of the clutch in the previous shift cycle, and to determine the theoretical oil drain time of the clutch in the previous shift cycle based on the oil circuit pressure and the pressure inside the piston chamber. The first oil filling module is used to use the first pressure as the oil filling pressure of the clutch in the current shift cycle if the actual oil discharge time in the previous shift cycle is greater than or equal to the theoretical oil discharge time. The basic filling module is used to use the basic filling pressure as the filling pressure of the clutch in the current shift cycle if the actual oil discharge time in the previous shift cycle is less than the theoretical oil discharge time; wherein, the basic filling pressure is the filling pressure corresponding to the friction plate reaching the half engagement point by filling the piston chamber volume of the clutch only. The first pressure is greater than the basic filling pressure.

9. An automatic transmission, characterized in that, The system includes a controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the automatic transmission clutch refill control method as described in any one of claims 1 to 7.

10. A vehicle, characterized in that, include: The automatic transmission as described in claim 9.

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