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

Abstract

The invention provides a method and a device for determining a joint point of a hydraulic clutch, a vehicle, equipment and a medium, and relates to the technical field of clutch control. The preset change trend is used for representing a corresponding pressure value change trend when the pressure value is transited from a relatively stable rising rate state to a continuously increasing rising rate state in the oil filling process, so that an inflection point for converting the pressure value from stable rising to rapid pressurization in the whole oil filling and pressure building process is determined; the inflection point can be regarded as a point where pressure in a hydraulic loop tends to rise rapidly under the influence of resistance of the driving end of the hydraulic clutch when the hydraulic clutch is combined, and a pressure value corresponding to the point can be regarded as a pressure value of a clutch combination point. Through the mode, high-voltage equipment such as a motor / an engine does not need to be started, operation can be carried out in a low-voltage state, influence factors are reduced, and the stability and accuracy of self-learning are guaranteed.

Description

Technical Field

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

[0002] The hydraulic clutch currently used in hybrid power systems is different from the traditional clutch in design, and at the same time, it avoids the slipping and grinding conditions with poor driving performance in control. The design and material costs of the clutch have both decreased, and the system thermal protection design and cost have also decreased year-on-year. In contrast, the clutch will consider the control characteristics more, requiring the engagement and separation process to be fast and smooth, while avoiding the occurrence of slipping and grinding conditions. Therefore, the control must ensure that the KP point of the clutch is accurate and clear.

[0003] When using the clutch for transmission in a hybrid system, the front end of the clutch needs to be regulated first, and the clutch is engaged after the front and rear ends are relatively stationary. The KP point needs to be referenced for relevant control during the clutch engagement process. Therefore, the accuracy of the clutch KP point is very high.

[0004] At present, the self-learning process of the KP point often determines the power source torque change and speed change caused by the separation and engagement of the clutch active end (front end) and the driven end (rear end) through the collaboration of the power source (engine / motor) and the clutch, so as to determine the KP point of the clutch. When the power source is running, the vehicle needs to be in a high voltage state, and performing KP point self-learning on the actual vehicle is prone to cause unexpected vehicle movement, which poses certain risks. The determined KP point will also be affected by the performance of the power source, and the accuracy is not high. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, vehicle, equipment and medium for determining the engagement point of a hydraulic clutch to address the above-mentioned technical problems, 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: obtaining in real time the pressure value of a target pressure collection point on a hydraulic circuit during the oil filling process of the hydraulic clutch; determining whether the change trend of the pressure value during the oil filling process up to the current moment conforms to a preset change trend, and if so, 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 collection point.

[0007] In an embodiment of the present application, the determination of whether the changing trend of the pressure value in the oil filling process up to the current moment meets the preset changing trend 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 the preset second-order pressure change rate threshold, then judging whether the first filtering condition corresponding to the pressure value, the second filtering condition corresponding to the first-order pressure change rate, and the third filtering condition corresponding to the second-order pressure change rate are established; if the first filtering condition, the second filtering condition, and the third filtering condition are all established, it is determined that the changing trend of the pressure value in the oil filling process up to the current moment meets the preset changing trend.

[0008] In an embodiment of the present 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 a candidate first-order pressure change rate based on the pressure value at the current moment and the pressure value at the previous moment; performing a first-order filtering 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 to obtain the first-order pressure change rate corresponding to the pressure value at the current moment; 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 an embodiment of the present application, the first screening condition includes: 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 a preset pressure threshold.

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

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

[0012] In an embodiment of the present application, before filling the hydraulic clutch with oil, the method also includes: determining whether the vehicle is in a parked and powered-off state, and if so, starting a drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

[0013] In an embodiment of the present application, the target pressure value based on the target pressure collection point is used to determine the engagement point of the hydraulic clutch, including: determining the difference between any two target pressure values ​​in combination with the target pressure values ​​determined during multiple oil filling processes; if all the differences do not exceed the difference threshold, calculating the average value of all the target pressure values; when the pressure value at the target pressure collection point is the average value, the position of the hydraulic clutch is used 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, used to acquire in real time the pressure value of a target pressure collection point on a hydraulic circuit during the oil filling process of the hydraulic clutch; a first determination module, used to determine whether the change trend of the pressure value during the oil filling process up to the current moment meets the preset change trend, and if so, the pressure value at the current moment is determined as the target pressure value; a second determination module, used to determine the engagement point of the hydraulic clutch based on the target pressure value of the target pressure collection point.

[0015] In an embodiment of the present application, the first determination 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 a preset second-order pressure change rate threshold, then respectively determine whether the first filtering condition corresponding to the pressure value, the second filtering condition corresponding to the first-order pressure change rate, and the third filtering condition corresponding to the second-order pressure change rate are established, and determine that as of the current moment, the change trend of the pressure value during the oil filling process meets the preset change trend.

[0016] In an embodiment of the present application, the first determination module is used to: calculate a candidate first-order pressure change rate 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 rate 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; 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 an embodiment of the present application, the first screening condition includes: 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 a preset pressure threshold.

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

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

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

[0021] In an embodiment of the present application, the second determination module is used to: determine the difference between any two target pressure values ​​in combination with 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 collection point is the average value, the position of the hydraulic clutch is used as the engagement point of the hydraulic clutch.

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

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

[0024] A computer-readable storage medium stores a computer program, 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 embodiment.

[0025] In summary, the method for determining the engagement point of the hydraulic clutch proposed in the present application analyzes whether the changing trend of the pressure value during the oil filling and pressure building process meets the preset changing trend. If it does, it can be considered that the hydraulic clutch has entered the engaged state, and the target pressure value at the current moment can be used as the pressure value of the target pressure collection point when the hydraulic clutch enters the engaged state. The engagement point of the hydraulic clutch can be determined based on the target pressure value. In this way, the oil filling and pressure building process of the hydraulic clutch can be achieved only by operating the relevant components of the hydraulic clutch system, without starting high-voltage equipment such as the motor / engine, so that the method for determining the engagement point of the hydraulic clutch of the present application can be performed under low-pressure conditions, and the KP point is determined by analyzing the pressure change, reducing the control parameters and equipment involved in the self-learning of the KP point, reducing the influencing factors, reducing the deviation caused by external interference, and determining the KP point by means of mathematical analysis to ensure the stability and accuracy of self-learning. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0027] Figure 1 It is a schematic diagram of the structure of a hydraulic clutch system of a hybrid vehicle; Figure 2 is a flow chart of a method for determining a hydraulic clutch engagement point according to an exemplary embodiment of the present application; Figure 3 is a flow chart of a method for determining a hydraulic clutch engagement point according to another exemplary embodiment of the present application; Figure 4 is a flow chart of a method for determining a hydraulic clutch engagement point according to another exemplary embodiment of the present application; Figure 5 It is a schematic diagram of the correspondence between an original pressure change curve, a first-order pressure change rate curve, a second-order pressure change rate curve, and a target pressure value sampling curve in a method for determining a hydraulic clutch engagement point according to another exemplary embodiment of the present application; Figure 6 is a flow chart of a method for determining a hydraulic clutch engagement point according to another exemplary embodiment of the present application; Figure 7 is a schematic block diagram of a device for determining an engagement point of a hydraulic clutch according to another exemplary embodiment of the present application; Figure 8 is a schematic block diagram of a vehicle according to an exemplary embodiment of the present application; Fig. 9 It is a schematic block diagram of an electronic device according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described by reference to the drawings are exemplary and are intended to be used to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, but does not exclude the presence or addition of one or more other features, integers, steps, operations and / or groups thereof.

[0030] It should also be understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] As used in the present specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]", depending on the context.

[0032] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0033] References to "one embodiment" or "some embodiments" etc. described in the present specification mean that one or more embodiments of the present invention include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0034] In the power coupling system of a hybrid vehicle or the transmission system of a fuel vehicle, the driving force of the power source (engine or drive motor) is transmitted to the driving wheels of the vehicle through the engagement of the clutch, and the power transmission is interrupted by the disengagement of the clutch. The method for determining the engagement point of the hydraulic clutch proposed in this application can be used to determine or update the engagement point of the clutch, or to realize the self-learning process of the engagement point of the hydraulic clutch.

[0035] by Figure 1Taking the hydraulic clutch system of the hybrid vehicle shown as an example, the hydraulic clutch engagement point determination method proposed in the present application is used to fill the hydraulic circuit with oil by driving the pump 1 to realize the pressure building process of the hydraulic clutch 5. The pressure value change at a fixed point during the oil filling and pressure building process is analyzed by analyzing the first-order pressure change rate. Further, the speed of the pressure value change at the fixed point during the pressure building process is analyzed by analyzing the second-order pressure change rate. Based on the change in the pressure value and the speed of the pressure value change, the inflection point where the pressure value changes from stable rise to rapid pressure increase is determined from the entire pressure building process. It is not difficult to understand that as the oil filling continues, the pressure at the driven end of the clutch gradually increases, and the two ends of the clutch in a separated state under the action of pressure continue to approach until they are in contact. After the driven end and the active end of the clutch are in contact, the pressure at the driven end changes from a stable rise to a rapid pressure increase due to the resistance of the active 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 rise to a rapid pressure increase during the pressure building process can be determined, thereby determining the pressure value corresponding to the clutch engagement point. In this way, the oil filling and pressure building process of the hydraulic clutch can be achieved only by operating the relevant components of the hydraulic clutch system, without starting high-voltage equipment such as the motor / engine, so that the method for determining the hydraulic clutch engagement point of the present application can be carried out under low-pressure conditions. The KP point is determined by analyzing the pressure change, and the control parameters and equipment involved in the KP point self-learning are reduced, reducing influencing factors and reducing deviations caused by external interference. The KP point is determined by means of mathematical analysis to ensure the stability and accuracy of self-learning.

[0036] Figure 2 is a flow chart of a method for determining a hydraulic clutch engagement point according to an exemplary embodiment of the present application. Figure 2 As shown, the method comprises the following steps: S201, obtaining in real time the pressure value of a target pressure collection point on the hydraulic circuit during the oil filling process of the hydraulic clutch.

[0037] like Figure 1 In the hydraulic clutch system shown, the drive pump 1 is used to provide hydraulic power, and the liquid flowing out of the electric drive pump outlet flows through the hydraulic circuit, through the reversing valve 4, and flows into the hydraulic clutch 5 through the reversing valve 4. Multiple hydraulic clutches can be provided as needed, and this application does not limit it.

[0038] The target pressure collection point can be set at any position in the hydraulic circuit, such as at the inlet end of the throttle hole 3, or the inlet of the reversing valve, etc.

[0039] The pressure value during the oil filling process of the hydraulic clutch can be collected in real time by setting a pressure collection device such as a pressure sensor 2 at the target pressure collection point.

[0040] It should be noted that the oil filling process of the present application is started when the hydraulic clutch is in a disengaged state, and oil is filled through the hydraulic circuit to implement pressure building.

[0041] In some embodiments, a single pressure building process can be completed by controlling the driving pump to operate intermittently at preset time intervals. That is, the driving pump is controlled to work for a period of time, then stop running, and continue to work after stopping for a period of time, and repeat this process. When to end the oil filling process can be determined in the following ways: for example, the oil filling time is set, and the time to end the oil filling process is determined based on the oil filling time. The oil filling time can be determined through multiple oil filling experiments. For another example, the oil filling process can be ended when the pressure value at the target pressure collection point reaches a preset pressure threshold.

[0042] For example, the oil filling process may include the following stages: After starting the KP point self-learning task (i.e. starting the process of determining the engagement point of the hydraulic clutch), control the drive pump to run and build pressure. After the drive pump has worked for 10 seconds, it stops running, waits for 10 seconds for the hydraulic circuit to release pressure naturally, and then controls the drive pump to continue running and building pressure. After the pressure is built up three times in this cycle, the oil filling process ends.

[0043] In some embodiments, the pressure may be continuously built up, and the oil filling process may be terminated after a preset time period is reached.

[0044] After one oil filling process is completed, if the next oil filling process is to be started, the hydraulic oil in the hydraulic circuit can be returned to the drive pump by opening the throttle hole in the hydraulic circuit.

[0045] S202, determining whether the change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend, and if so, determining the pressure value at the current moment as the target pressure value.

[0046] As the oil filling and pressure building process continues, the pressure value at the target pressure collection point will continue to change. In some embodiments, the pressure value change trend can be analyzed by analyzing the size relationship between the pressure values ​​at different times and the change in the difference between the pressure values ​​at different times to determine whether the pressure value change trend during the oil filling process up to the current moment meets the preset change trend. The preset change trend can be expressed as a change trend corresponding to the pressure value going from a steady rise to a rapid pressure increase. The change trend can be defined as a fixed change trend by analyzing the pressure value, the direction of change of the pressure value (such as rising or falling), and the direction of change of the pressure value rising rate at different times. The preset change trend can be set based on the pressure change of the hydraulic circuit during the clutch entering the engaged state.

[0047] In other words, the preset change trend can be used to characterize the corresponding pressure value change trend when the pressure value transitions from a state of relatively stable rising rate to a state of continuously increasing rising rate during the oil filling process, wherein the "relatively stable state" can be limited by limiting the pressure value rising rate within a certain range.

[0048] S203: Determine the engagement point of the hydraulic clutch based on the target pressure value of the target pressure collection point.

[0049] The target pressure collection point and the hydraulic clutch are in the same hydraulic circuit. The pressure value of the target pressure collection 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 practice, there will be a corresponding relationship between the pressure borne by the driven end of the hydraulic clutch and 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.

[0050] In summary, the method for determining the engagement point of the hydraulic clutch proposed in the present application analyzes whether the change trend of the pressure value during the oil filling and pressure building process conforms to the preset change trend. The preset change trend is used to characterize the corresponding change trend of the pressure value when the pressure value transitions from a relatively stable rising rate state to a state of increasing rising rate during the oil filling process. In this way, the turning point of the pressure value from stable rising to rapid pressure increase is determined from the entire oil filling and pressure building process. The turning point can be regarded as the point where the pressure in the hydraulic circuit is affected by the resistance of the active end of the hydraulic clutch when the hydraulic clutch is engaged and shows a rapid rising trend. 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 pressure building process of the hydraulic clutch can be realized only by operating the relevant components of the hydraulic clutch system, and there is no need to start high-voltage equipment such as the motor / engine, so that the method for determining the engagement point of the hydraulic clutch of the present application can be carried out under low pressure. The KP point is determined by analyzing the pressure change, the control parameters and equipment involved in the self-learning of the KP point are reduced, the influencing factors are reduced, and the deviation caused by external interference is reduced. The KP point is determined by means of mathematical analysis to ensure the stability and accuracy of self-learning.

[0051] On the basis of the above embodiment, before the step S201 of "filling the hydraulic clutch with oil", the following judgment process is also included: It is determined whether the vehicle is in a parked and powered-off state. If the vehicle is in a parked and powered-off state, a driving pump in a hydraulic clutch system is started to fill the hydraulic clutch with oil through the hydraulic circuit.

[0052] The present application does not require the aid of external equipment and the vehicle's power source to perform self-learning of the KP point. It controls the driving pump of the hydraulic clutch system to fill oil and build pressure under low pressure. By analyzing the pressure changes and change trends during the filling and pressure building process, the target pressure value can be screened out. The present application can be implemented using a lower voltage, and learning can be performed after the vehicle is parked and powered off, thereby reducing the impact on users and driving safety.

[0053] Furthermore, the following judgment process may also be included to determine whether the vehicle needs to perform KP point self-learning: judging based on the mileage recorded by the whole vehicle and the performance attenuation of the clutch, when the mileage of the whole vehicle is greater than the Od1 threshold, or the mileage is greater than the Od2 threshold and the clutch KP point performance is detected to be abnormal, it is determined that KP point self-learning is required, then the request for self-learning flag position 1 is set, and after waiting for the upper layer to decide that the whole vehicle enters the parking and power-off state, the KP point self-learning is started, and the KP point has been updated through the method for determining the hydraulic clutch engagement point proposed in this application.

[0054] The Od1 threshold may be greater than the Od2 threshold. Whether the clutch KP point has performance abnormalities can be determined by monitoring the hydraulic clutch KP point abnormality flag.

[0055] When the corresponding conditions are met, KP point self-learning is enabled, which reduces the number of triggering of the self-learning process while ensuring the accuracy of the KP point, thereby reducing the computing pressure of the processing unit.

[0056] Based on the above embodiment, the above step S202 of "determining whether the change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend" may include the following process: First, calculate the first-order pressure change rate and second-order pressure change rate corresponding to the current pressure value: When the pressure value at a certain moment is obtained, the difference between the pressure value at this moment and the pressure value at the previous moment is calculated, as well as the time interval between this moment and the previous moment is calculated, and the first-order pressure change rate corresponding to the moment is determined by the ratio of the difference and the time interval; After determining the first-order pressure change rate at this moment, the difference between the first-order pressure change rate at this moment and the first-order pressure change rate at the previous moment is calculated, and the ratio of the difference to the above time interval is used as the second-order pressure change rate corresponding to the moment.

[0057] For example, the data processing process and the control process of the driving pump are carried out simultaneously, and the pressure value of the target pressure collection point is monitored simultaneously after the pressure buildup begins, and the fitting calculation of the first-order pressure change rate is performed, and then the fitting calculation of the second-order pressure change rate is further performed.

[0058] Then, according to 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 change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend: The present application pre-sets a first screening condition for the pressure value of the target pressure collection point during the oil filling process, sets a second screening condition for the first-order pressure change rate during the oil filling process, and sets a third screening condition for the second-order pressure change rate during the oil filling process.

[0059] In some embodiments, the first filtering condition can be used to filter and judge the pressure values ​​that have been collected, the second filtering condition can be used to filter the calculated first-order pressure change rate, and the third filtering condition can be used to filter the calculated second-order pressure change rate.

[0060] Among them, the preset change trend is a change trend jointly constrained by the first filtering condition, the second filtering condition and the third filtering condition, for example, the pressure value is in a certain pressure 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.

[0061] By constraining the second-order pressure change rate, the first-order pressure change rate and the pressure value, it is determined whether the speed of change of the pressure value in the oil filling process meets the preset change trend for a period of time up to the current moment. If so, it is determined that the driven end and the active 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 used as the target pressure value corresponding to the KP point.

[0062] Based on the above embodiments, Figure 3 As shown, in the above step of "calculating the first-order pressure change rate and the second-order pressure change rate corresponding to the pressure values ​​at different times", includes the following steps: S301, calculating a candidate first-order pressure change rate according to the pressure value at the current moment and the pressure value at the previous moment.

[0063] The pressure value P1 is obtained at time T1, the time of the previous pressure value collection of T1 is recorded as time T0, and the pressure value P0 is obtained at time T0. Then, the candidate first-order pressure change rate corresponding to the pressure value at time T1 is (P1-P0) / (T1-T0).

[0064] S302, performing first-order filtering 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 to obtain the first-order pressure change rate corresponding to the pressure value at the current moment; A first-order filtering process is performed on each calculated candidate first-order pressure change rate to smooth the fluctuation of the first-order change rate.

[0065] For example, the candidate first-order pressure change rate corresponding to the pressure value P1 at time T1 is calculated to be K1', and the first-order pressure change rate corresponding to the pressure value P0 at time T0 is K0. As the first-order pressure change rate K1 corresponding to the pressure value P1 at time T1.

[0066] The weighting coefficient a in the first-order filtering process can be set according to the required smoothing strength, and this application does not limit it.

[0067] S303, calculating a second-order pressure change rate corresponding to the pressure value at the current moment according to 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.

[0068] Calculate the difference K1-K0 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; and take (K1-K0) / (T1-T0) as the second-order pressure change rate corresponding to the pressure value at time T1.

[0069] Optionally, the above-mentioned filtering process may also be added when determining the second-order pressure change rate.

[0070] Among them, if the time required for the processing unit to collect the pressure value from the pressure sensor is 10ms, the time for a first-order filtering process is t, and after the first-order pressure change rate is calculated, the next pressure value is collected, then the above T1-T0=10ms+t.

[0071] This application smoothes the large fluctuations of the first-order pressure change rate by filtering the first-order pressure change rate when calculating the first-order pressure change rate, so as to avoid sudden changes in the calculated second-order pressure change rate. The influence of the fluctuation of the pressure curve during the oil filling process on the first-order pressure change rate curve and the second-order pressure change rate curve is avoided, and the change rate curve of the smooth process is obtained to accurately analyze the change trend of the pressure value.

[0072] Based on the above embodiments, Figure 4 As shown, in the above step, "determining whether the change trend of the pressure value during the oil filling process up to the current moment meets the preset change trend according to 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: S401, 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 determine whether the first filtering condition, the second filtering condition and the third filtering condition are met.

[0073] The second-order pressure change rate threshold can be set to 0, or set to any positive number close to 0 as needed. 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 of the target pressure collection point begins to increase rapidly. Figure 5 The corresponding relationship between the original pressure change curve, the first-order pressure change rate curve, and the second-order pressure change rate curve is shown.

[0074] The present application triggers the screening process when the pressure value starts to increase at an increasing rate of change, that is, when the second-order pressure change rate is greater than 0. The screening process is to determine whether the first screening condition corresponding to the pressure value is satisfied up to the current moment, whether the second screening condition corresponding to the first-order pressure change rate is satisfied, and whether the third screening condition corresponding to the second-order pressure change rate is satisfied.

[0075] S402: If the first screening condition, the second screening condition and the third screening condition are all satisfied, it is determined that up to the current moment, the pressure value change trend during the oil filling process meets the preset change trend.

[0076] If the first screening condition, the second screening condition and the third screening condition are satisfied at the same time up to the current moment, it is determined that the pressure value change trend during the oil filling process up to the current moment meets the preset change trend.

[0077] Optionally, the gradual increase or decrease in the rate of change of the pressure value can be limited by limiting the size of the second-order pressure change rate, such as limiting the size of the second-order pressure change rate at the current moment and the second-order pressure change rate at the previous moment; further, by constraining the first pressure change rate and the pressure value, the pressure range in which the target pressure value may appear can be defined, and the rate of change of the pressure value before the target pressure value appears can be limited, etc., so as to determine whether the change trend of the original pressure curve up to the current moment (that is, the pressure curve composed of pressure values ​​collected at the target pressure collection point at different moments) meets the preset change trend.

[0078] When the clutch is in the engaged state, the rate at which the pressure in the hydraulic circuit increases becomes faster. Before starting the screening, it is prioritized to determine whether the second-order pressure change rate exceeds the preset second-order pressure change rate threshold (the 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 streamline the processing process.

[0079] In some embodiments, the preset change trend of the present application can be set according to the pressure change trend in the hydraulic circuit during the process of the clutch entering the engaged state, so as to determine the starting point of the clutch engagement state, that is, the engagement point, by analyzing the pressure change of the target pressure collection point during the oil filling process.

[0080] Optionally, the first filtering condition corresponding to the pressure value may include: within a first preset time interval up to the current moment, the number of pressure values ​​satisfying the first filtering sub-condition exceeds a first threshold; wherein, the first filtering sub-condition includes: the pressure value is greater than a preset pressure threshold.

[0081] Among them, the preset pressure threshold can be set as needed, and this application does not impose any restrictions. For example, it is set to 1.5 bar.

[0082] In the present application, the preset pressure threshold can be used to filter out the stage before the clutch is ready to enter the engagement state. By setting the first preset time interval and the first threshold, it is determined whether the pressure value within a certain period of time can meet the constraint of the preset pressure threshold.

[0083] By setting the first threshold, a certain fault tolerance rate is guaranteed to adapt to the normal fluctuation of the pressure value of the target pressure collection point in practice. The first threshold can be set according to the sampling time of the pressure value and the first preset time interval. The specific value of the preset first preset time interval can be set as needed, and this application does not limit it.

[0084] In some embodiments, the second screening condition may include: the first-order pressure change rate is within a preset threshold range. The preset threshold range can be set as needed, such as [0.3, 0.8], so as to filter out the stage where the pressure value rises rapidly when the oil filling starts.

[0085] In some embodiments, the third filtering condition may include: within a second preset time interval up to the current moment, the number of second-order pressure change rates that meet the second filtering sub-condition exceeds a second threshold; wherein, the second filtering sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

[0086] The second threshold value can be set according to the second preset time interval and the pressure value sampling time, and the second threshold value is set to set a certain error tolerance for the second-order pressure change rate within a period of time. Correspondingly, the second threshold value can of course be set to the number of all second-order pressure change rates calculated within the second preset time interval.

[0087] It should be noted that the second preset time interval can be the same as the first preset time interval, or can be set to two different time intervals. The specific value can be set as needed, and this application does not limit it.

[0088] As mentioned in the above-mentioned embodiment, the present application sets a second preset time interval and a second threshold value in order to determine whether the second-order pressure change rate can generally meet the constraint of the second-order pressure change rate threshold value within a period of time, so as to cope with the inevitable pressure fluctuations in practice and improve the accuracy of the pressure change trend judgment, thereby ensuring the accuracy of the determined target pressure value and the accuracy of the determined clutch engagement point.

[0089] Combination Figure 5 For example, during the oil filling process, the present 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 starts to judge whether the calculated second-order pressure change rates are greater than 0 within the second preset time interval up to the current moment; and starts to judge whether the acquired pressure values ​​within the first preset time interval up to the current moment are greater than 1.5 bar, and starts 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 filtering conditions is not met, then continue to obtain the pressure value and calculate the first-order pressure change rate and the second-order pressure change rate until all three filtering conditions are met, and then take the pressure value at the current moment as the target pressure value, that is, Figure 5 The KP point pressure value recorded in.

[0090] Based on the above embodiments, Figure 6 As shown, in the above step S204, "determining the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point" includes: S601, determining the difference between any two target pressure values ​​in combination with the target pressure values ​​determined in multiple oil filling processes.

[0091] S602, if all the differences do not exceed the difference threshold, calculating the average value of all the target pressure values; S603: When the pressure value at the target pressure collection point is the average value, the position of the hydraulic clutch is used as the engagement point of the hydraulic clutch.

[0092] In the embodiment of the present application, a target pressure value can be determined in each oil filling process, and the target pressure value can be stored; the throttle hole 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. By implementing multiple oil filling processes, a target pressure value can be determined in each oil filling process. For example, three oil filling processes are performed continuously to obtain three target pressure values, and the differences between the three target pressure values ​​are calculated. If these differences do not exceed the difference threshold, such as not exceeding 0.3, the average value of the three target pressure values ​​is calculated, and the average value is used as the pressure value of the KP point, and the KP point of the clutch can be determined accordingly. If these differences exceed the difference threshold, the unqualified target pressure value is discarded, the oil filling process is rebuilt, and a new target pressure value is obtained again until the deviation between the three stored target pressure values ​​does not exceed 0.3.

[0093] The embodiment of the present application combines the target pressure values ​​determined in multiple oil filling processes to make a comprehensive judgment, averages multiple target pressure values ​​whose deviations do not exceed the difference threshold, and uses the average value as the pressure value of the KP point, thereby reducing the impact of errors in the KP point determination process and improving accuracy.

[0094] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean 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 the present application.

[0095] Figure 7 is a schematic block diagram of a device for determining a hydraulic clutch engagement point according to another exemplary embodiment of the present application. Figure 7 As shown, the apparatus 700 includes an acquisition module 701 , a first determination module 702 , and a second determination module 703 .

[0096] An acquisition module 701 is used to acquire in real time the pressure value of a target pressure collection point on the hydraulic circuit during the oil filling process of the hydraulic clutch; The first determination module 702 is used to determine whether the change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend, and if so, determine the pressure value at the current moment as the target pressure value; The second determination module 703 is used to determine the engagement point of the hydraulic clutch based on the target pressure value of the target pressure collection point.

[0097] In the embodiment of the present application, the first determination 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 current pressure value 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 satisfied; It is determined that up to the current moment, the change trend of the pressure value during the oil filling process meets the preset change trend.

[0098] In an embodiment of the present application, the first determination module is used to: calculate a candidate first-order pressure change rate 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 rate 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; 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.

[0099] In an embodiment of the present application, the first screening condition includes: 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 a preset pressure threshold.

[0100] In an embodiment of the present application, the second screening condition includes: the first-order pressure change rate is within a preset threshold range.

[0101] In an embodiment of the present application, the third filtering condition includes: within a second preset time interval up to the current moment, the number of second-order pressure change rates that meet the second filtering sub-condition exceeds a second threshold; wherein, the second filtering sub-condition includes: the second-order pressure change rate is greater than a preset second-order pressure change rate threshold.

[0102] In an embodiment of the present application, the acquisition module is used to: determine whether the vehicle is in a parked and powered-off state; if so, start the drive pump in the hydraulic clutch system to fill the hydraulic clutch with oil through the hydraulic circuit.

[0103] In an embodiment of the present application, the second determination module is used to: determine the difference between any two target pressure values ​​in combination with 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 collection point is the average value, the position of the hydraulic clutch is used as the engagement point of the hydraulic clutch.

[0104] In summary, the device for determining the engagement point of the hydraulic clutch proposed in the present application uses the first-order pressure change rate to analyze the change of the pressure value at a fixed point during the pressure building process. Further, the speed of the pressure value change at the fixed point during the pressure building process is analyzed by analyzing the second-order pressure change rate. Based on the change of the pressure value and the speed of the pressure value change, the turning point where the pressure value changes from a stable rise to a rapid pressure increase is determined from the entire pressure building process. The turning point can be regarded as the point where the pressure in the hydraulic circuit is affected by the resistance of the active end of the hydraulic clutch when the hydraulic clutch is engaged and shows a rapid rising trend. 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 pressure building process of the hydraulic clutch can be realized only by operating the relevant components of the hydraulic clutch system, and there is no need to start high-voltage equipment such as the motor / engine, so that the method for determining the engagement point of the hydraulic clutch of the present application can be carried out under low pressure. The KP point is determined by analyzing the pressure change trend, the control parameters and equipment involved in the self-learning of the KP point are reduced, the influencing factors are reduced, and the deviation caused by external interference is reduced. The KP point is determined by means of mathematical analysis to ensure the stability and accuracy of self-learning.

[0105] In order to implement the above embodiment, the present application embodiment also proposes a vehicle 800, such as Figure 8 As shown, the system includes a hydraulic clutch system 801 and the device 700 for determining the hydraulic clutch engagement point described in the above embodiment.

[0106] In order to implement the above embodiment, the present application embodiment also proposes an electronic device 900, such as Fig. 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, the steps of the method for determining the engagement point of the hydraulic clutch as shown in the above embodiment are implemented.

[0107] To implement the above embodiments, the present application also proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method for determining the engagement point of the hydraulic clutch described in any of the above embodiments are implemented.

[0108] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may 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 many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0109] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by 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.

[0110] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for determining the engagement point of a hydraulic clutch, characterized in that: The method comprises: Real-time acquisition of the pressure value of the target pressure collection point on the hydraulic circuit during the oil filling process of the hydraulic clutch; Determine whether the change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend, and if so, determine the pressure value at the current moment as the target pressure value; Based on the target pressure value of the target pressure collection point, the engagement point of the hydraulic clutch is determined.

2. The method according to claim 1, characterized in that The determining whether the change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend includes: 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 current pressure value 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 satisfied; If the first screening condition, the second screening condition and the third screening condition are all satisfied, it is determined that up to the current moment, the change trend of the pressure value in the oil filling process meets the preset change trend.

3. The method according to claim 2, characterized in that The calculating the first-order pressure change rate and the second-order pressure change rate corresponding to the pressure value at the current moment includes: Calculate the candidate first-order pressure change rate according to 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, first-order filtering is performed to obtain the first-order pressure change rate corresponding to the pressure value at the current moment; The second-order pressure change rate corresponding to the pressure value at the current moment is calculated according to 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.

4. The method according to claim 2, characterized in that The first screening condition includes: In a first preset time interval up to the current moment, the number of pressure values ​​satisfying the first screening sub-condition exceeds a first threshold; Wherein, the first screening sub-condition includes: the pressure value is greater than a preset pressure threshold.

5. The method according to claim 2, characterized in that The second screening condition includes: The first-order pressure change rate is within a preset threshold range.

6. The method according to claim 2, characterized in that The third screening condition includes: In a second preset time interval up to the current moment, the number of second-order pressure change rates satisfying 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.

7. The method according to claim 1, characterized in that Before filling the hydraulic clutch with oil, the method further includes: It is determined whether the vehicle is in a parked and powered-off state. If the vehicle is in a parked and powered-off state, a driving pump in a hydraulic clutch system is started to fill the hydraulic clutch with oil through the hydraulic circuit.

8. The method according to claim 1, characterized in that The step of determining the engagement point of the hydraulic clutch based on the target pressure value of the target pressure acquisition point comprises: Determine the difference between any two target pressure values ​​by combining the target pressure values ​​determined during the multiple oil filling processes; 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 collection point is the average value, the position of the hydraulic clutch serves as the engagement point of the hydraulic clutch.

9. A device for determining the engagement point of a hydraulic clutch, characterized in that: The device comprises: An acquisition module, used for acquiring in real time the pressure value of a target pressure collection point on the hydraulic circuit during the oil filling process of the hydraulic clutch; A first determination module is used to determine whether the change trend of the pressure value in the oil filling process up to the current moment meets the preset change trend, and if so, determine the pressure value at the current moment as the target pressure value; The second determination module is used to determine the engagement point of the hydraulic clutch based on the target pressure value of the target pressure collection point.

10. A vehicle, characterized in that: It comprises a hydraulic clutch system and a device for determining the engagement point of the hydraulic clutch as claimed in claim 9.

11. 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, the steps of the method for determining the engagement point of the hydraulic clutch as described in any one of claims 1-8 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for determining the engagement point of the hydraulic clutch as described in any one of claims 1 to 8 are implemented.

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