Method and device for determining hydraulic clutch engagement point, vehicle, equipment and medium

Abstract

This application proposes a method, device, vehicle, equipment, and medium for determining the engagement point of a hydraulic clutch, relating to the field of clutch control technology. The method analyzes whether the pressure value change trend during the oil filling process conforms to a preset trend. This preset trend characterizes the pressure value change trend during the oil filling process as the pressure value transitions from a relatively stable rate of increase to a state of continuously increasing rate of increase. Based on this, the inflection point where the pressure value changes from a stable increase to rapid pressure increase is determined throughout the entire oil filling and pressure building process. This inflection point can be considered as the point where the pressure in the hydraulic circuit exhibits a rapid upward trend due to the resistance of the hydraulic clutch's driving end during engagement. The pressure value corresponding to this point can be used as the pressure value of the clutch engagement point. This method eliminates the need to start high-pressure equipment such as motors / engines, allowing operation under low-pressure conditions, reducing influencing factors, and ensuring the stability and accuracy of self-learning.

Description

Technical Field

[0001] This application relates to the field of hydraulic clutch control technology, and in particular to a method, device, vehicle, equipment and medium for determining the engagement point of a hydraulic clutch. Background Technology

[0002] The hydraulic clutch currently used in hybrid power systems differs from traditional clutches in design and avoids slippage conditions that lead to poor driving performance. The design and material costs of this clutch are reduced, and the system's thermal protection design and cost are also reduced accordingly. In contrast, this clutch requires more consideration of control characteristics, demanding rapid and smooth engagement and disengagement while avoiding slippage conditions. Therefore, the control must ensure that the clutch's KP point is accurate and clear.

[0003] When using a clutch for transmission in a hybrid power system, the speed of the clutch tip must first be adjusted. The clutch is then engaged only after the front and rear ends are relatively stationary. Controlling clutch engagement requires referencing the KP point. Therefore, the accuracy of the clutch KP point is extremely important.

[0004] Currently, the self-learning process of KP point often involves the collaboration of the power source (engine / motor) and the clutch to determine the torque and speed changes of the power source caused by the separation and engagement of the clutch's driving end (front end) and driven end (rear end). This determines the clutch's KP point. However, the vehicle needs to be in a high-voltage state when the power source is running, and performing KP point self-learning on a real vehicle can easily lead to unexpected lurching of the vehicle, posing a certain risk. Furthermore, the determined KP point is also affected by the performance of the power source, resulting in low accuracy. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, device, vehicle, equipment, and medium for determining the engagement point of a hydraulic clutch, which does not require the participation of a power source, reduces the impact of the engagement point determination process on vehicle safety and occupant safety, and improves the accuracy of the engagement point.

[0006] A method for determining the engagement point of a hydraulic clutch, the method comprising: acquiring, in real time, the pressure value of a target pressure acquisition point on the hydraulic circuit during the oil filling process of the hydraulic clutch; determining whether the trend of the pressure value change during the oil filling process up to the current moment conforms to a preset trend; if it does, determining the pressure value at the current moment as the target pressure value; and determining the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point.

[0007] In this embodiment of the application, determining whether the pressure value change trend during the oil filling process conforms to a preset change trend up to the current moment includes: calculating the first-order pressure change rate and the second-order pressure change rate corresponding to the pressure value at the current moment; if the second-order pressure change rate corresponding to the pressure value at the current moment is greater than a preset second-order pressure change rate threshold, then determining whether the first screening condition corresponding to the pressure value, the second screening condition corresponding to the first-order pressure change rate, and the third screening condition corresponding to the second-order pressure change rate are valid; if the first screening condition, the second screening condition, and the third screening condition are all valid, it is determined that the pressure value change trend during the oil filling process conforms to the preset change trend up to the current moment.

[0008] In this embodiment of the application, the calculation of the first-order pressure change rate and the second-order pressure change rate corresponding to the pressure value at the current moment includes: calculating candidate first-order pressure change rates based on the pressure value at the current moment and the pressure value at the previous moment; performing first-order filtering based on the candidate first-order pressure change rates and the first-order pressure change rate corresponding to the pressure value at the previous moment to obtain the first-order pressure change rate corresponding to the pressure value at the current moment; and calculating the second-order pressure change rate corresponding to the pressure value at the current moment based on the first-order pressure change rate corresponding to the pressure value at the current moment and the first-order pressure change rate corresponding to the pressure value at the previous moment.

[0009] In this embodiment of the application, the first screening condition includes: within a first preset time interval up to the current moment, the number of pressure values ​​that satisfy the first screening sub-condition exceeds a first threshold; wherein, the first screening sub-condition includes: the pressure value is greater than the preset pressure threshold.

[0010] In this embodiment of the application, the second screening condition includes: the first-order pressure change rate is within a preset threshold range.

[0011] In this embodiment of the application, the third screening condition includes: within a second preset time interval up to the current moment, the number of second-order pressure change rates that satisfy the second screening sub-condition exceeds a second threshold; wherein, the second screening sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

[0012] In this embodiment of the application, before filling the hydraulic clutch with oil, the method further includes: determining whether the vehicle is in a parked and power-off state; if it is in a parked and power-off state, starting the drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

[0013] In this embodiment of the application, determining the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point includes: combining the target pressure values ​​determined during multiple oil filling processes to determine the difference between any two target pressure values; if all the differences do not exceed the difference threshold, then calculating the average value of all the target pressure values; when the pressure value at the target pressure acquisition point is the average value, the position of the hydraulic clutch is taken as the engagement point of the hydraulic clutch.

[0014] A device for determining the engagement point of a hydraulic clutch, the device comprising: an acquisition module for acquiring, in real time, the pressure value of a target pressure acquisition point on the hydraulic circuit during the oil filling process of the hydraulic clutch; a first determination module for determining whether the trend of the pressure value change during the oil filling process up to the current moment conforms to a preset trend, and if so, determining the pressure value at the current moment as the target pressure value; and a second determination module for determining the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point.

[0015] In this embodiment of the application, the first determining module is used to: calculate the first-order pressure change rate and the second-order pressure change rate corresponding to the pressure value at the current moment; if the second-order pressure change rate corresponding to the pressure value at the current moment is greater than the preset second-order pressure change rate threshold, then determine whether the first screening condition corresponding to the pressure value, the second screening condition corresponding to the first-order pressure change rate, and the third screening condition corresponding to the second-order pressure change rate are valid, and determine that up to the current moment, the change trend of the pressure value during the oil filling process conforms to the preset change trend.

[0016] In this embodiment of the application, the first determining module is configured to: calculate candidate first-order pressure change rates based on the pressure value at the current moment and the pressure value at the previous moment; perform first-order filtering based on the candidate first-order pressure change rates and the first-order pressure change rates corresponding to the pressure value at the previous moment to obtain the first-order pressure change rate corresponding to the pressure value at the current moment; and calculate the second-order pressure change rate corresponding to the pressure value at the current moment based on the first-order pressure change rate corresponding to the pressure value at the current moment and the first-order pressure change rate corresponding to the pressure value at the previous moment.

[0017] In this embodiment of the application, the first screening condition includes: within a first preset time interval up to the current moment, the number of pressure values ​​that satisfy the first screening sub-condition exceeds a first threshold; wherein, the first screening sub-condition includes: the pressure value is greater than the preset pressure threshold.

[0018] In this embodiment of the application, the second screening condition includes: the first-order pressure change rate is within a preset threshold range.

[0019] In this embodiment of the application, the third screening condition includes: within a second preset time interval up to the current moment, the number of second-order pressure change rates that satisfy the second screening sub-condition exceeds a second threshold; wherein, the second screening sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

[0020] In this embodiment of the application, the acquisition module is used to: determine whether the vehicle is in a parked and power-off state; if it is in a parked and power-off state, start the drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

[0021] In this embodiment of the application, the second determining module is used to: determine the difference between any two target pressure values ​​by combining the target pressure values ​​determined during multiple oil filling processes; if all the differences do not exceed the difference threshold, calculate the average value of all the target pressure values; when the pressure value at the target pressure acquisition point is the average value, the position of the hydraulic clutch is taken as the engagement point of the hydraulic clutch.

[0022] A vehicle includes a hydraulic clutch system and a device for determining the engagement point of the hydraulic clutch as described in the above embodiments.

[0023] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the method for determining the engagement point of a hydraulic clutch as described in any of the above embodiments.

[0024] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for determining the engagement point of a hydraulic clutch as described in the above embodiments.

[0025] In summary, the method for determining the engagement point of the hydraulic clutch proposed in this application analyzes whether the pressure value change trend during the oil filling and pressurization process conforms to a preset change trend. If it does, the hydraulic clutch can be considered to have entered the engagement state. The target pressure value at the current moment can be used as the pressure value at the target pressure acquisition point when the hydraulic clutch enters the engagement state. The engagement point of the hydraulic clutch can be determined based on this target pressure value. In this way, the oil filling and pressurization process of the hydraulic clutch can be achieved by operating only the relevant components of the hydraulic clutch system, without the need to start high-pressure equipment such as motors / engines. This allows the method for determining the engagement point of the hydraulic clutch in this application to be performed under low pressure. By analyzing pressure changes to determine the KP point, the number of control parameters and equipment involved in the self-learning of the KP point is reduced, influencing factors are reduced, and deviations caused by external interference are reduced. The KP point is determined through mathematical analysis, ensuring the stability and accuracy of the self-learning process. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a hydraulic clutch system for a hybrid electric vehicle.

[0028] Figure 2 This is a flowchart illustrating a method for determining the engagement point of a hydraulic clutch according to an exemplary embodiment of this application;

[0029] Figure 3 This is a flowchart illustrating a method for determining the engagement point of a hydraulic clutch according to another exemplary embodiment of this application;

[0030] Figure 4 This is a flowchart illustrating a method for determining the engagement point of a hydraulic clutch according to another exemplary embodiment of this application;

[0031] Figure 5 This is a schematic diagram illustrating the correspondence between the original pressure change curve, the first-order pressure change rate curve, the second-order pressure change rate curve, and the target pressure value sampling curve in a method for determining the engagement point of a hydraulic clutch according to another exemplary embodiment of this application.

[0032] Figure 6 This is a flowchart illustrating a method for determining the engagement point of a hydraulic clutch according to another exemplary embodiment of this application;

[0033] Figure 7 This is a schematic block diagram of a device for determining the engagement point of a hydraulic clutch according to another exemplary embodiment of this application;

[0034] Figure 8 This is a schematic block diagram of a vehicle according to an exemplary embodiment of this application;

[0035] Figure 9 This is a schematic block diagram of an electronic device according to an exemplary embodiment of this application. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The embodiments described with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0037] It should be understood that, when used in the specification and appended claims of this invention, the term "comprising" indicates the presence of the described feature, integral, step, or operation, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, and / or a collection thereof.

[0038] It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0039] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0040] Furthermore, in the description of this invention and the appended claims, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0041] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of the invention include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0042] In hybrid electric vehicles, the power coupling system, or in the transmission system of a gasoline-powered vehicle, transmits the driving force of the power source (engine or drive motor) to the vehicle's drive wheels through the engagement of a clutch, and interrupts the power transmission by disengaging the clutch. The method for determining the engagement point of a hydraulic clutch proposed in this application can be used to determine or update the clutch engagement point, or in other words, to achieve a self-learning process for the hydraulic clutch engagement point.

[0043] by Figure 1 Taking the hydraulic clutch system of the hybrid electric vehicle shown as an example, the hydraulic clutch engagement point determination method proposed in this application is used. The hydraulic circuit is filled with oil by the operation of the drive pump 1 to realize the pressure build-up process of the hydraulic clutch 5. The pressure value change at a fixed point during the oil filling and pressure build-up process is analyzed by analyzing the first-order pressure change rate. Furthermore, the rate of pressure change at that fixed point during the pressure build-up process is analyzed by analyzing the second-order pressure change rate. Based on the pressure value change and its rate of change, the inflection point where the pressure value changes from a stable increase to rapid pressure increase is determined throughout the entire pressure build-up process. It is easy to understand that as oil filling continues, the pressure at the driven end of the clutch gradually increases. Under the action of pressure, the two ends of the clutch, which are in a disengaged state, continuously approach each other until they contact. After the driven end and the driving end of the clutch contact, the pressure at the driven end changes from a stable increase to rapid pressure increase due to the resistance of the driving end. This pressure change process can be reflected at any point in the hydraulic circuit. Therefore, by analyzing the pressure change and pressure change trend at a fixed point in the hydraulic circuit, the inflection point where the pressure value changes from a stable increase to rapid pressure increase during the pressure build-up process can be determined, thereby determining the pressure value corresponding to the clutch engagement point. In this way, the hydraulic clutch can be pressurized by simply operating the relevant components of the hydraulic clutch system, without the need to start high-pressure equipment such as motors / engines. This allows the method for determining the hydraulic clutch engagement point of this application to be performed under low pressure. By analyzing pressure changes, the KP point is determined, reducing the control parameters and equipment involved in the self-learning of the KP point, reducing influencing factors, and reducing deviations caused by external interference. The KP point is determined through mathematical analysis, ensuring the stability and accuracy of the self-learning process.

[0044] Figure 2 This is a flowchart illustrating a method for determining the engagement point of a hydraulic clutch according to an exemplary embodiment of this application, such as... Figure 2 As shown, the method includes the following steps:

[0045] S201, Real-time acquisition of the pressure value at the target pressure acquisition point on the hydraulic circuit during the hydraulic clutch filling process.

[0046] like Figure 1In the hydraulic clutch system shown, drive pump 1 provides hydraulic power. Liquid flowing from the outlet of the electric drive pump passes through the hydraulic circuit, then through directional valve 4, and finally into hydraulic clutch 5. Multiple hydraulic clutches can be provided as needed; this application does not impose any limitation.

[0047] The target pressure acquisition point can be set at any location in the hydraulic circuit, such as at the inlet end of the throttle orifice 3, or at the inlet of the directional valve, etc.

[0048] Pressure values ​​during the hydraulic clutch filling process can be collected in real time by setting pressure sensor 2 and other pressure acquisition devices at the target pressure acquisition point.

[0049] It should be noted that the oil filling process in this application is initiated when the hydraulic clutch is in a disengaged state, and oil is filled through the hydraulic circuit to build up pressure.

[0050] In some embodiments, a single pressure build-up process can be completed by controlling the drive pump to operate intermittently at preset time intervals. That is, the drive pump operates for a period of time, then stops, then resumes operation after a certain period, and so on. The end of the oil filling process can be determined in the following ways: for example, by setting an oil filling duration, and determining the end time based on this duration; this duration can be determined through multiple oil filling experiments. Another example is that the oil filling process can end when the pressure value at the target pressure acquisition point reaches a preset pressure threshold.

[0051] For example, the oil filling process may include the following stages:

[0052] After starting the KP point self-learning task (i.e. the process of determining the engagement point of the hydraulic clutch), control the drive pump to run and build up pressure. After the drive pump runs for 10 seconds, stop running and wait for 10 seconds to allow the hydraulic circuit to release pressure naturally. Then control the drive pump to continue running and build up pressure. After this cycle of building up pressure 3 times, the oil filling process ends.

[0053] In some embodiments, pressure can be continuously built up until a preset time is reached, at which point the oil filling process ends.

[0054] After one oil filling process is completed, if you want to start the next oil filling process, you can open the throttle orifice in the hydraulic circuit to return the hydraulic oil in the hydraulic circuit to the drive pump.

[0055] S202, determine whether the pressure value change trend during the oil filling process up to the current moment conforms to the preset change trend. If it does, then determine the pressure value at the current moment as the target pressure value.

[0056] As oil filling and pressurization continue, the pressure value at the target pressure acquisition point will constantly change. In some embodiments, the trend of pressure change can be analyzed by examining the magnitude relationship between pressure values ​​at different times and the changes in the difference between pressure values ​​at different times. This allows for determination of whether the pressure change trend during the oil filling process conforms to a preset trend up to the current moment. This preset trend can be represented as the trend corresponding to the transition from a steady rise in pressure to rapid pressurization. This trend can be defined by analyzing the pressure value, the direction of pressure change (e.g., rising or falling), and the direction of the rate of increase of the pressure value at different times. This preset trend can be set based on the pressure changes in the hydraulic circuit during the clutch engagement process.

[0057] Alternatively, this preset trend can be used to characterize the pressure value change trend during the oil filling process when the pressure value transitions from a state with a relatively stable rate of increase to a state with a continuously increasing rate of increase. The "relatively stable state" can be defined by limiting the rate of increase of the pressure value within a certain range.

[0058] S203, Based on the target pressure value of the target pressure acquisition point, determine the engagement point of the hydraulic clutch.

[0059] The target pressure acquisition point and the hydraulic clutch are in the same hydraulic circuit. The pressure value of the target pressure acquisition point can be considered as the pressure value borne by the driven end of the hydraulic clutch. When the pressure borne by the driven end is the target pressure value, the position of the driven end of the hydraulic clutch is determined as the engagement point of the hydraulic clutch. In reality, there will be a corresponding relationship between the pressure borne by the driven end of the hydraulic clutch, the position of the driven end of the hydraulic clutch, the position of the clutch pedal, and the parameters of each component in the entire hydraulic clutch control mechanism. After determining the pressure value when the hydraulic clutch starts to contact and enters the engagement state, the engagement point of the hydraulic clutch and the corresponding parameters of each component in the hydraulic clutch control mechanism in this state can be determined.

[0060] In summary, the hydraulic clutch engagement point determination method proposed in this application analyzes whether the pressure value change trend during the oil filling and pressurization process conforms to a preset trend. This preset trend characterizes the pressure value change trend when the pressure value transitions from a relatively stable rising rate to a continuously increasing rising rate during the oil filling process. This allows for the determination of the inflection point where the pressure value changes from a stable rise to rapid pressurization throughout the entire oil filling and pressurization process. This inflection point can be considered as the point where the pressure in the hydraulic circuit exhibits a rapid upward trend due to the resistance of the hydraulic clutch's active end during clutch engagement. The pressure value corresponding to this point can be used as the pressure value of the clutch engagement point. In this way, the oil filling and pressurization process of the hydraulic clutch can be achieved simply by operating the relevant components of the hydraulic clutch system, without needing to start high-pressure equipment such as motors / engines. This allows the hydraulic clutch engagement point determination method of this application to be performed under low-pressure conditions. By analyzing pressure changes to determine the KP point, the number of control parameters and equipment involved in the KP point self-learning is reduced, influencing factors are minimized, and deviations caused by external interference are reduced. The determination of the KP point through mathematical analysis ensures the stability and accuracy of the self-learning process.

[0061] Based on the above embodiments, before "filling the hydraulic clutch with oil" in step S201, the following judgment process is also included:

[0062] Determine whether the vehicle is in a parked and power-off state. If it is, start the drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

[0063] This application does not require external equipment or vehicle power source for KP point self-learning. Under low pressure, it controls the hydraulic clutch system's drive pump to build up oil pressure. By analyzing the pressure changes and trends during the oil pressure building process, the target pressure value can be selected. This application can be achieved using a relatively low voltage. It can be put into operation after the vehicle is parked and powered off to learn, reducing the impact on users and driving safety.

[0064] Furthermore, the following judgment process may be included to determine whether the vehicle needs to perform KP point self-learning: Based on the vehicle's recorded mileage and the performance degradation of the clutch, if the vehicle's mileage is greater than the Od1 threshold, or the mileage is greater than the Od2 threshold and abnormal clutch KP point performance is detected, and it is determined that KP point self-learning is required, then the self-learning flag position will be requested to be 1. After the upper layer decides that the vehicle enters a parking and power-off state, KP point self-learning will be started, and the KP point will be updated using the hydraulic clutch engagement point determination method proposed in this application.

[0065] The Od1 threshold can be greater than the Od2 threshold. The presence of performance abnormalities at the KP point of the hydraulic clutch can be determined by monitoring the abnormal flag bit of the KP point.

[0066] KP point self-learning is enabled when the corresponding conditions are met, which reduces the number of times the self-learning process is triggered while ensuring the accuracy of KP points and reducing the computational pressure on the processing unit.

[0067] Based on the above embodiments, step S202, "determining whether the trend of pressure value change during the oil filling process conforms to a preset trend up to the current moment," may include the following process:

[0068] First, calculate the first-order and second-order rates of change of pressure corresponding to the current pressure value:

[0069] When the pressure value at a certain moment is obtained, the difference between the pressure value at that moment and the pressure value at the previous moment is calculated, as well as the time interval between the two moments. The ratio of the difference to the time interval is used to determine the first-order pressure change rate at that moment.

[0070] After determining the first-order pressure change rate at that moment, calculate the difference between the first-order pressure change rate at that moment and the first-order pressure change rate at the previous moment, and use the ratio of this difference to the aforementioned time interval as the second-order pressure change rate corresponding to that moment.

[0071] For example, the data processing process and the pump control process are carried out simultaneously. After the pressure build-up begins, the pressure value of the target pressure acquisition point is monitored at the same time, and the first-order pressure change rate is fitted and calculated. Then, the second-order pressure change rate is fitted and calculated.

[0072] Then, based on the first screening condition corresponding to the pressure value, the second screening condition corresponding to the first-order pressure change rate, and the third screening condition corresponding to the second-order pressure change rate, it is determined whether the trend of pressure value change during the oil filling process up to the current moment conforms to the preset trend:

[0073] This application pre-sets a first screening condition for the pressure value of the target pressure acquisition point during the oil filling process, a second screening condition for the first-order pressure change rate during the oil filling process, and a third screening condition for the second-order pressure change rate during the oil filling process.

[0074] In some embodiments, the collected pressure values ​​can be filtered using a first filtering condition, the calculated first-order pressure change rate can be filtered using a second filtering condition, and the calculated second-order pressure change rate can be filtered using a third filtering condition.

[0075] The preset trend is the trend constrained by the first, second and third screening conditions. For example, the pressure value is within a certain range within a certain period of time, and the pressure value gradually increases, and the rate of increase of the pressure value continues to increase, etc.

[0076] By constraining the second-order pressure change rate, the first-order pressure change rate, and the pressure value, it is determined whether, up to the current moment, the pressure value changes at a rate that meets the preset trend for a certain period of time during the oil filling process. If so, it is determined that the driven end and the driving end of the hydraulic clutch are in the initial stage of entering the engagement state during the current oil filling process, and the pressure value at the current moment is taken as the target pressure value corresponding to point KP.

[0077] Based on the above embodiments, such as Figure 3 As shown, the step above, "calculating the first-order and second-order pressure change rates corresponding to pressure values ​​at different times," includes the following steps:

[0078] S301, calculate the candidate first-order pressure change rate based on the pressure value at the current moment and the pressure value at the previous moment.

[0079] The pressure value P1 is acquired at time T1. The previous pressure value acquisition time is recorded as time T0. The pressure value P0 is acquired at time T0. Then the candidate first-order pressure change rate corresponding to the pressure value at time T1 is (P1-P0) / (T1-T0).

[0080] S302, based on the candidate first-order pressure change rate and the first-order pressure change rate corresponding to the pressure value at the previous moment, perform first-order filtering to obtain the first-order pressure change rate corresponding to the pressure value at the current moment.

[0081] Each candidate first-order pressure change rate is processed by first-order filtering to smooth the fluctuations in the first-order change rate.

[0082] For example, if the calculated first-order pressure change rate corresponding to the pressure value P1 at time T1 is K1', and the first-order pressure change rate corresponding to the pressure value P0 at time T0 is K0, then... K1 is the first-order pressure change rate corresponding to the pressure value P1 at time T1.

[0083] The weighting coefficient 'a' in the first-order filtering process can be set according to the required smoothing intensity, and this application does not impose any limitations on it.

[0084] S303, calculate the second-order pressure change rate corresponding to the pressure value at the current moment based on the first-order pressure change rate corresponding to the pressure value at the current moment and the first-order pressure change rate corresponding to the pressure value at the previous moment.

[0085] Calculate the difference between the first-order pressure change rate K1 corresponding to the pressure value at time T1 and the first-order pressure change rate K0 corresponding to the pressure value at time T0, K1-K0; take (K1-K0) / (T1-T0) as the second-order pressure change rate corresponding to the pressure value at time T1.

[0086] Optionally, the above filtering process can be added when determining the second-order pressure change rate.

[0087] If the processing unit takes 10ms to acquire the pressure value from the pressure sensor, and the time for one first-order filtering is t, then after calculating the first-order pressure change rate, the next pressure value is acquired, and the above T1-T0=10ms+t.

[0088] This application filters the first-order pressure change rate during calculation to smooth out large fluctuations and prevent abrupt changes in the calculated second-order pressure change rate. This avoids the influence of pressure curve fluctuations during oil filling on both the first-order and second-order pressure change rate curves, resulting in a smoothed process change rate curve for accurate analysis of pressure value trends.

[0089] Based on the above embodiments, such as Figure 4 As shown, the step described above, "determining whether the trend of pressure change during the oil filling process conforms to a preset trend up to the current moment, based on the first screening condition corresponding to the pressure value, the second screening condition corresponding to the first-order pressure change rate, and the third screening condition corresponding to the second-order pressure change rate," includes:

[0090] S401, if the second-order pressure change rate corresponding to the pressure value at the current moment is greater than the preset second-order pressure change rate threshold, then determine whether the first screening condition, the second screening condition and the third screening condition are valid respectively.

[0091] The second-order pressure change rate threshold can be set to 0, or, as needed, to any positive number approaching 0. When the second-order pressure change rate is greater than 0, it can be considered that the first-order pressure change rate at the current moment is greater than the first-order pressure change rate at the previous moment, and the pressure value at the target pressure acquisition point begins to increase rapidly. For example... Figure 5 The correspondence between the original pressure change curve, the first-order pressure change rate curve, and the second-order pressure change rate curve is shown.

[0092] This application triggers a screening process when the pressure value begins to increase at an increasingly larger rate of change, i.e., when the second-order pressure change rate is greater than 0. This screening process involves determining whether the first screening condition corresponding to the pressure value up to the current moment is met, whether the second screening condition corresponding to the first-order pressure change rate is met, and whether the third screening condition corresponding to the second-order pressure change rate is met.

[0093] S402, if the first screening condition, the second screening condition and the third screening condition are all met, it is determined that the pressure value change trend during the oil filling process conforms to the preset change trend up to the current time.

[0094] If, up to the current moment, the first, second, and third screening conditions are all met simultaneously, then it is determined that, up to the current moment, the pressure value change trend during the oil filling process conforms to the preset change trend.

[0095] Optionally, the rate of change of pressure value can be limited by restricting the magnitude of the second-order pressure change rate, such as limiting the magnitude of the second-order pressure change rate at the current moment and the second-order pressure change rate at the previous moment. Furthermore, by constraining the first pressure change rate and the pressure value, the pressure range in which the target pressure value may occur can be defined, and the rate of change of pressure value before the target pressure value occurs can be limited, etc., so as to determine whether the trend of change of the original pressure curve (i.e., the pressure curve composed of pressure values ​​collected at the target pressure collection point at different times) up to the current moment conforms to the preset trend.

[0096] During the process of the clutch entering the engagement state, the rate at which the pressure in the hydraulic circuit increases becomes faster. Before starting the screening, it is first determined whether the second-order pressure change rate exceeds the preset second-order pressure change rate threshold (this change rate threshold is greater than or equal to 0). This can filter out the stage where the pressure value changes more and more slowly, avoid interference from other data, and simplify the processing.

[0097] In some embodiments, the preset change trend of this application can be set according to the pressure change trend in the hydraulic circuit during the clutch entering the engagement state, so as to determine the starting point of the clutch engagement state, i.e. the engagement point, by analyzing the pressure change at the target pressure acquisition point during the oil filling process.

[0098] Optionally, the first screening condition corresponding to the pressure value may include: within a first preset time interval up to the current moment, the number of pressure values ​​that meet the first screening sub-condition exceeds a first threshold; wherein, the first screening sub-condition includes: the pressure value is greater than the preset pressure threshold.

[0099] The preset pressure threshold can be set as needed, and this application does not impose any restrictions; for example, it can be set to 1.5 bar.

[0100] In this application, a preset pressure threshold can be used to filter out the stage before the clutch is ready to engage. By setting a first preset time interval and a first threshold, it is determined whether the pressure value within a certain time period can meet the constraint of the preset pressure threshold.

[0101] A first threshold is set to ensure a certain fault tolerance rate, in order to accommodate normal fluctuations in the pressure values ​​at the target pressure sampling points in actual operation. The first threshold can be set based on the pressure value sampling time and a first preset time interval. The specific value of this first preset time interval can be set as needed, and this application does not impose any restrictions.

[0102] In some embodiments, the second screening condition may include: the first-order pressure change rate is within a preset threshold range. This preset threshold range can be set as needed, such as [0.3, 0.8]. This filters out the phase where the pressure value rises rapidly at the start of oil filling.

[0103] In some embodiments, the third screening condition may include: within a second preset time interval up to the current moment, the number of second-order pressure change rates that satisfy the second screening sub-condition exceeds a second threshold; wherein the second screening sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

[0104] The second threshold can be set according to the second preset time interval and the pressure value sampling time. Setting the second threshold is used to set a certain tolerance for the second-order pressure change rate over a period of time. Correspondingly, the second threshold can be set as the number of all second-order pressure change rates calculated within the second preset time interval.

[0105] It should be noted that the second preset time interval can be the same as the first preset time interval, or it can be set to two different time intervals. The specific value can be set as needed, and this application does not limit it.

[0106] As described in the above embodiments, this application sets a second preset time interval and a second threshold in order to determine whether the second-order pressure change rate can meet the constraint of the second-order pressure change rate threshold as a whole within a certain period of time, so as to cope with the unavoidable pressure fluctuations in reality, improve the accuracy of the judgment of the pressure change trend, thereby ensuring the accuracy of the determined target pressure value and the accuracy of the determined clutch engagement point.

[0107] Combination Figure 5For example, during the oil filling process, this application judges the real-time acquired pressure value, the real-time calculated first-order pressure change rate, and the second-order pressure change rate. When the second-order pressure change rate is greater than 0, it begins to judge whether the calculated second-order pressure change rate within the second preset time interval up to the current moment is all greater than 0; and it begins to judge whether the acquired pressure value within the first preset time interval up to the current moment is all greater than 1.5 bar; and it begins to judge whether the first-order pressure change rate at the current moment is between [0.3, 0.8]. If it is determined at the current moment that any of the above three screening conditions is not met, the acquisition of pressure value and the calculation of first-order pressure change rate and second-order pressure change rate continue until all three screening conditions are met. Then, the pressure value at the current moment is taken as the target pressure value, i.e. Figure 5 The pressure value at point KP recorded in the data.

[0108] Based on the above embodiments, such as Figure 6 As shown, step S204 above, "determining the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point," includes:

[0109] S601, combined with the target pressure values ​​determined during multiple oil filling processes, determines the difference between any two target pressure values.

[0110] S602, if none of the differences exceed the difference threshold, then calculate the average value of all the target pressure values;

[0111] S603, when the pressure value at the target pressure acquisition point is the average value, the position of the hydraulic clutch is taken as the engagement point of the hydraulic clutch.

[0112] In this embodiment, a target pressure value can be determined and stored during each oil filling process. The throttle orifice in the hydraulic circuit is opened to return the hydraulic oil in the hydraulic circuit to the drive pump, and then the next oil filling process is restarted. Multiple oil filling processes can be implemented, with a target pressure value determined in each process. For example, three consecutive oil filling processes can be performed to obtain three target pressure values. The differences between these three target pressure values ​​are calculated. If these differences do not exceed a difference threshold (e.g., not exceeding 0.3), the average of the three target pressure values ​​is calculated and used as the pressure value of the KP point, corresponding to the determination of the clutch's KP point. If these differences exceed the difference threshold, the unqualified target pressure value is discarded, the oil filling process is re-started, and a new target pressure value is obtained, until the deviation between the three stored target pressure values ​​does not exceed 0.3.

[0113] This application embodiment combines the target pressure values ​​determined during multiple oil filling processes for comprehensive judgment. Based on multiple target pressure values ​​whose deviations do not exceed the difference threshold, the average value is taken as the pressure value of the KP point, thereby reducing the impact of errors in the KP point determination process and improving accuracy.

[0114] 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.

[0115] Figure 7 This is a schematic block diagram of a hydraulic clutch engagement point determination device according to another exemplary embodiment of this application, such as... Figure 7 As shown, the device 700 includes an acquisition module 701, a first determination module 702, and a second determination module 703.

[0116] The acquisition module 701 is used to acquire the pressure value of the target pressure acquisition point on the hydraulic circuit during the hydraulic clutch filling process in real time.

[0117] The first determining module 702 is used to determine whether the trend of the pressure value during the oil filling process up to the current moment conforms to the preset trend. If it does, the pressure value at the current moment is determined as the target pressure value.

[0118] The second determining module 703 is used to determine the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point.

[0119] In this embodiment of the application, the first determining module is used to: calculate the first-order pressure change rate and the second-order pressure change rate corresponding to the pressure value at the current moment;

[0120] If the second-order pressure change rate corresponding to the pressure value at the current moment is greater than the preset second-order pressure change rate threshold, then determine whether the first screening condition corresponding to the pressure value, the second screening condition corresponding to the first-order pressure change rate, and the third screening condition corresponding to the second-order pressure change rate are valid.

[0121] It has been determined that, up to the current moment, the trend of pressure value change during the oil filling process conforms to the preset trend.

[0122] In this embodiment of the application, the first determining module is configured to: calculate candidate first-order pressure change rates based on the pressure value at the current moment and the pressure value at the previous moment; perform first-order filtering based on the candidate first-order pressure change rates and the first-order pressure change rates corresponding to the pressure value at the previous moment to obtain the first-order pressure change rate corresponding to the pressure value at the current moment; and calculate the second-order pressure change rate corresponding to the pressure value at the current moment based on the first-order pressure change rate corresponding to the pressure value at the current moment and the first-order pressure change rate corresponding to the pressure value at the previous moment.

[0123] In this embodiment of the application, the first screening condition includes: within a first preset time interval up to the current moment, the number of pressure values ​​that satisfy the first screening sub-condition exceeds a first threshold; wherein, the first screening sub-condition includes: the pressure value is greater than the preset pressure threshold.

[0124] In this embodiment of the application, the second screening condition includes: the first-order pressure change rate is within a preset threshold range.

[0125] In this embodiment of the application, the third screening condition includes: within a second preset time interval up to the current moment, the number of second-order pressure change rates that satisfy the second screening sub-condition exceeds a second threshold; wherein, the second screening sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

[0126] In this embodiment of the application, the acquisition module is used to: determine whether the vehicle is in a parked and power-off state; if it is in a parked and power-off state, start the drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

[0127] In this embodiment of the application, the second determining module is used to: determine the difference between any two target pressure values ​​by combining the target pressure values ​​determined during multiple oil filling processes; if all the differences do not exceed the difference threshold, calculate the average value of all the target pressure values; when the pressure value at the target pressure acquisition point is the average value, the position of the hydraulic clutch is taken as the engagement point of the hydraulic clutch.

[0128] In summary, the hydraulic clutch engagement point determination device proposed in this application utilizes the first-order pressure change rate to analyze the pressure value change at a fixed point during the pressure build-up process. Furthermore, it analyzes the second-order pressure change rate to determine the rate of pressure change at that fixed point during the pressure build-up process. Based on the pressure value change and its rate of change, the inflection point where the pressure value transitions from a stable increase to rapid pressure increase is determined throughout the entire pressure build-up process. This inflection point can be considered as the point where the pressure in the hydraulic circuit exhibits a rapid upward trend due to the resistance at the driving end of the hydraulic clutch during engagement. The pressure value corresponding to this point can be used as the pressure value of the clutch engagement point. In this way, the hydraulic clutch's oil filling and pressure build-up process can be achieved simply by operating the relevant components of the hydraulic clutch system, without needing to start high-pressure equipment such as motors / engines. This allows the hydraulic clutch engagement point determination method of this application to be performed under low-pressure conditions. By analyzing the pressure change trend to determine the KP point, the number of control parameters and equipment involved in the KP point self-learning is reduced, influencing factors are minimized, and deviations caused by external interference are reduced. The determination of the KP point through mathematical analysis ensures the stability and accuracy of the self-learning process.

[0129] To achieve the above embodiments, this application also proposes a vehicle 800, such as... Figure 8 As shown, the device includes a hydraulic clutch system 801 and a hydraulic clutch engagement point determination device 700 as described in the above embodiment.

[0130] To implement the above embodiments, this application also proposes an electronic device 900, such as... Figure 9 As shown, the electronic device 900 may specifically include: a memory 901, a processor 902, and a computer program stored in the memory 901 and executable on the processor 902. When the processor 902 executes the program, it implements the steps of the method for determining the engagement point of the hydraulic clutch as described in the above embodiment.

[0131] To implement the above embodiments, this application also proposes a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the method for determining the engagement point of the hydraulic clutch as described in any of the above embodiments.

[0132] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0133] 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 used as 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.

[0134] 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 determining the engagement point of a hydraulic clutch, characterized in that, The method includes: Real-time acquisition of pressure values ​​at target pressure acquisition points on the hydraulic circuit during the hydraulic clutch filling process; Determine whether the pressure value change trend during the oil filling process up to the current moment conforms to the preset change trend. If it does, then the pressure value at the current moment is determined as the target pressure value. Based on the target pressure value at the target pressure acquisition point, the engagement point of the hydraulic clutch is determined; Determining whether the trend of pressure value change during the oil filling process up to the current time conforms to a preset trend includes: Calculate the first-order and second-order rates of change of pressure corresponding to the pressure value at the current moment; If the second-order pressure change rate corresponding to the pressure value at the current moment is greater than the preset second-order pressure change rate threshold, then determine whether the first screening condition corresponding to the pressure value, the second screening condition corresponding to the first-order pressure change rate, and the third screening condition corresponding to the second-order pressure change rate are valid. If the first screening condition, the second screening condition, and the third screening condition are all met, it is determined that, up to the current moment, the trend of the pressure value during the oil filling process conforms to the preset trend.

2. The method as described in claim 1, characterized in that, The calculation of the first-order and second-order pressure change rates corresponding to the pressure value at the current moment includes: Calculate the candidate first-order pressure change rate based on the pressure value at the current moment and the pressure value at the previous moment; Based on the candidate first-order pressure change rate and the first-order pressure change rate corresponding to the pressure value at the previous moment, a first-order filter is performed to obtain the first-order pressure change rate corresponding to the pressure value at the current moment. Based on the first-order rate of change of the pressure value at the current moment and the first-order rate of change of the pressure value at the previous moment, calculate the second-order rate of change of the pressure value at the current moment.

3. The method as described in claim 1, characterized in that, The first filtering criteria include: Within the first preset time interval up to the current moment, the number of pressure values ​​that meet the first screening sub-condition exceeds the first threshold. The first screening sub-condition includes: the pressure value is greater than a preset pressure threshold.

4. The method as described in claim 1, characterized in that, The second screening criteria include: The first-order pressure change rate is within a preset threshold range.

5. The method as described in claim 1, characterized in that, The third screening criteria include: Within the second preset time interval up to the current moment, the number of second-order pressure change rates that satisfy the second screening sub-condition exceeds the second threshold. The second screening sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

6. The method as described in claim 1, characterized in that, Before filling the hydraulic clutch with oil, the method further includes: Determine whether the vehicle is in a parked and power-off state. If it is, start the drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

7. The method as described in claim 1, characterized in that, Determining the engagement point of the hydraulic clutch based on the target pressure value from the target pressure acquisition point includes: By combining the target pressure values ​​determined during multiple oil filling processes, the difference between any two target pressure values ​​is determined; If none of the above differences exceed the difference threshold, then calculate the average of all the target pressure values; When the pressure value at the target pressure acquisition point is the average value, the position of the hydraulic clutch is taken as the engagement point of the hydraulic clutch.

8. A device for determining the engagement point of a hydraulic clutch, used to implement the method as described in claim 1, characterized in that, The device includes: The acquisition module is used to acquire the pressure value of the target pressure acquisition point on the hydraulic circuit during the hydraulic clutch filling process in real time. The first determining module is used to determine whether the trend of pressure value change during the oil filling process up to the current moment conforms to the preset trend. If it does, the pressure value at the current moment is determined as the target pressure value. The second determining module is used to determine the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point.

9. A vehicle, characterized in that, It includes a hydraulic clutch system and a device for determining the engagement point of the hydraulic clutch as described in claim 8.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for determining the engagement point of the hydraulic clutch as described in any one of claims 1-7.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the steps of the method for determining the engagement point of the hydraulic clutch as described in any one of claims 1-7.

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