Pressure Sensor Zero Drift Adaptive Method, Pressure Calculation Method, System, Vehicle and Medium

Abstract

The present invention relates to a zero-drift adaptive method for a pressure sensor, a pressure calculation method, a system, a vehicle and a medium, including: when it is determined that the state of the clutch is oil discharge, triggering a clutch oil discharge timer to time the oil discharge time of the clutch; obtaining the current oil temperature of the transmission and calculating the maximum oil discharge time threshold of the clutch at the current oil temperature; when it is detected that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature, using the current pressure sensor voltage value as the zero-point voltage value of the pressure sensor. The present invention can accurately adapt to the zero drift of the pressure sensor in a timely manner, improving the calculation accuracy of the effective acting pressure of the clutch.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle pressure sensors, and particularly to a zero-drift adaptive method for a pressure sensor, a pressure calculation method, a system, a vehicle and a medium. Background Art

[0002] In a wet dual-clutch transmission, the clutch pressure sensor is an important signal monitoring component that real-time detects the actual pressure in the clutch oil passage. The TCU control system performs precise pressure closed-loop control on the clutch according to this pressure signal, thereby ensuring the clutch torque control accuracy. The absolute pressure sensor is widely used in the wet dual-clutch hydraulic system due to its mature technology and low cost. When using an absolute pressure sensor, the effective pressure acting on the wet clutch is the difference between the absolute oil pressure detected in the clutch oil passage and the internal air pressure of the gearbox. At this time, the internal air pressure of the gearbox is the zero drift of the absolute pressure sensor. During vehicle driving, as the oil temperature rises, the wet dual-clutch gearbox body is filled with oil vapor. When the internal air pressure is higher than the external ambient air pressure of the gearbox, the oil vapor is discharged through the one-way exhaust valve on the box body, thereby achieving the dynamic balance of the air pressure inside and outside the box. Affected by external factors such as altitude and atmospheric pressure, at the same oil temperature, the air pressure inside the box is also different. In addition, for mass-produced wet dual-clutch transmissions, affected by hardware such as sensors, wiring harnesses, sensor connectors, and TCU controllers, under the same internal air pressure conditions of the gearbox, there are also varying degrees of differences in the sensor voltage signals monitored by the TCU controller. Therefore, how to accurately and adaptively calculate the zero-drift value of the pressure sensor in a timely manner is very important for the pressure and torque control of the wet clutch, and will greatly affect the vehicle performance, especially the low-speed performance such as crawling and starting.

[0003] An adaptive method for zero - point drift of an engine pressure sensor disclosed in patent document CN104879228B includes the following steps: S11: Detect and determine whether the engine is in an operating state, that is, whether the engine speed is zero. If so, execute step S12; S12: The ECU of the engine controls the throttle valve to close to ensure that there is no gas flow inside the engine. At this time, the pressure sensor is not affected by external pressure. In theory, the pressure sensor should be at zero point; S13: Collect the zero - point voltage of the pressure sensor at this time, that is, obtain the detected value U0 of the zero - point voltage of the pressure sensor. Specifically, the method of collecting multiple times and performing stable filtering and then taking the average value can be used to obtain the detected value U0 of the zero - point voltage, that is, U0 is the average value obtained from multiple detections, so as to more truly and effectively reflect the offset situation; S14: Determine whether U0 is within a predetermined range. The maximum value Umax and the minimum value Umin of the zero - point voltage of the pressure sensor can be set. At this time, it can be determined whether U0 is between Umax and Umin, that is, whether U0 is greater than or equal to Umin and less than or equal to Umax. If so, execute step S15. If not, execute step S16; S15: Read the theoretical value UE of the zero - point voltage of the pressure sensor from the EEPROM of the engine, and obtain the difference between the theoretical value and the detected value, denoted as △U; S16: Send an alarm signal for pressure sensor failure. The alarm signal can be an audible and visual alarm signal to remind the operator to repair or replace the pressure sensor; S17: Determine whether the absolute value of the difference △U is less than a predetermined value. If not, execute step S18; S18: Store △U in the EEPROM for use when the engine starts next time; S19: After the engine runs normally, read the difference △U in step S15 from the EEPROM; S20: Collect the voltage value U through the pressure sensor, then use △U to correct the voltage value U, denote the corrected voltage value as UF, and then use the corrected voltage value UF as the effective voltage value to convert to the corresponding pressure value, so that the engine can use this pressure value for corresponding processing and control. This method is applicable to the pressure sensor of the engine to eliminate the drawback of inaccurate measurement of various engine parameters caused by zero - point drift of the pressure sensor, and then achieve precise control of the engine, optimize the performance of the engine, especially the emission performance of the engine. However, when the external environmental air pressure changes little during the continuous operation of the engine, this method can effectively achieve the self - adaptation of the sensor zero - point drift, improve the control accuracy of the engine speed and torque, optimize the performance of the engine, and save the cost of purchasing hardware and the time required to change the circuit compared with the form of changing circuit hardware, which is more economical and efficient.However, the following problems exist in this method: Judging whether the engine speed is 0 as the trigger condition for the zero-drift self-adaptation of the pressure sensor. In fact, during the vehicle driving process, the external ambient air pressure is very likely to change continuously. For example, when continuously driving a vehicle up and down the plateau, at this time, the pressure sensor cannot achieve zero-drift self-adaptation.

[0004] Therefore, it is necessary to develop a new zero-drift self-adaptation method for pressure sensors, a pressure calculation method, a system, a vehicle and a storage medium. Summary of the Invention

[0005] The purpose of the present invention is to provide a zero-drift self-adaptation method, system, vehicle and storage medium for pressure sensors, which can accurately adapt to the zero-drift of the pressure sensor in a timely manner.

[0006] Another purpose of the present invention is to provide a calculation method, system, vehicle and storage medium for the effective acting pressure of a clutch, which can improve the calculation accuracy of the effective acting pressure of the clutch.

[0007] In the first aspect, a zero-drift self-adaptation method for a pressure sensor according to the present invention includes the following steps:

[0008] In response to determining that the state of the clutch is oil drainage, trigger a clutch oil drainage timer to time the oil drainage time of the clutch;

[0009] Obtain the current oil temperature of the transmission and calculate the maximum oil drainage time threshold of the clutch at the current oil temperature;

[0010] In response to detecting that the oil drainage time of the clutch is greater than the maximum oil drainage time threshold at the corresponding temperature, use the current pressure sensor voltage value as the zero-point voltage value of the pressure sensor.

[0011] Optionally, to determine whether the clutch enters the oil drainage state, specifically:

[0012] Judge whether the following conditions are all satisfied. If so, it means that the clutch enters the oil drainage state, otherwise it means that the clutch does not enter the oil drainage state;

[0013] 1) The clutch torque request is 0, determining that the clutch has no torque control requirement;

[0014] 2) The clutch pressure request is 0, determining that the clutch has no pressure control requirement;

[0015] 3) The clutch output command pressure is 0, determining that the clutch pressure control valve does not output a command pressure;

[0016] 4) The clutch current request is 0, determining that the clutch pressure control valve has no current request;

[0017] 5) When the actual current of the clutch is 0, it is determined that the clutch pressure control valve is in the closed state, and the clutch oil passage is drained through the control valve;

[0018] 6) When the change rate of the voltage value of the clutch pressure sensor is less than the set voltage threshold, it is determined that the clutch has entered a stable oil drainage process. The voltage threshold in this embodiment is preferably set to 10 mv. This method uses the judgment of whether the clutch is in a non-operating state and whether the clutch oil drainage is completed as the trigger condition for the zero drift self-adaptation of the pressure sensor, so it is not affected by external environments such as altitude and atmospheric pressure. The calculation method is simple and reliable, and it can adapt to the air pressure change in the gearbox efficiently and in a timely manner. In view of the deficiencies of the existing solutions and combined with the characteristics of the wet dual-clutch transmission, the present invention proposes a simpler and more effective method for the zero drift self-adaptation of the pressure sensor, which can accurately self-adapt to the zero drift of the sensor in a timely manner.

[0019] Optionally, calculate the maximum oil drainage time threshold of the clutch at the current oil temperature, specifically:

[0020] Look up the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures through the current oil temperature of the transmission to obtain the maximum oil drainage time threshold of the clutch at the current oil temperature. Calculating the maximum oil drainage time threshold of the clutch by looking up the table has a simple calculation method and high efficiency.

[0021] Optionally, the method for obtaining the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures is as follows:

[0022] Test the oil drainage time of multiple clutches at different oil temperatures;

[0023] Take the maximum value of the oil drainage time of each clutch at the same oil temperature as the maximum oil drainage time of the clutch at that oil temperature;

[0024] Form the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures by corresponding the maximum oil drainage time with the oil temperature one by one.

[0025] The present invention stores the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures in the TCU memory. When the oil drainage of the clutch is completed, the clutch oil passage communicates with the atmosphere inside the gearbox. At this time, the pressure value detected by the pressure sensor is the internal air pressure of the gearbox, that is, the zero drift value of the pressure sensor. In order to avoid the influence of the residual oil pressure in the clutch oil passage on the zero point voltage value of the pressure sensor, it is necessary to ensure that the clutch has completed oil drainage before the zero drift self-adaptation of the pressure sensor. The main factor affecting the clutch oil drainage process is the oil temperature. Therefore, it is necessary to test the oil drainage time of the clutch at different oil temperatures. In addition, due to manufacturing and assembly errors, different clutches have different oil drainage times. The oil drainage time curves of multiple clutch samples can be tested, and the maximum value of the oil drainage time in all test samples can be taken as the maximum oil drainage time of the clutch.

[0026] Optionally, before using the current pressure sensor voltage value as the zero voltage value of the pressure sensor, perform time-domain average filtering on the voltage signal of the pressure sensor, and record the filtered sensor voltage value as the zero voltage value of the pressure sensor. The time-domain average filtering refers to performing average filtering on the pressure sensor voltage values within 5 consecutive TCU task cycles to improve the accuracy of the zero voltage value.

[0027] In a second aspect, a method for calculating the effective acting pressure of a clutch according to the present invention includes the following steps:

[0028] Obtain the zero voltage value of the pressure sensor by using the zero-drift adaptive method of the pressure sensor as described in the present invention;

[0029] Obtain the voltage value V output by the pressure sensor out ;

[0030] According to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out Calculate the effective acting pressure P of the clutch.

[0031] Optionally, the calculation method of the effective acting pressure P of the clutch is:

[0032] P = (V out - V0) / K;

[0033] Wherein, K is the voltage-pressure conversion factor, and V0 is the zero voltage value of the pressure sensor.

[0034] In a third aspect, a zero-drift adaptive system of a pressure sensor according to the present invention includes:

[0035] A clutch state determination unit, configured to determine whether the clutch enters an oil discharge state, and when it is determined that the state of the clutch is oil discharge, trigger a clutch oil discharge timer to time the oil discharge time of the clutch;

[0036] A clutch maximum oil discharge time threshold calculation unit, configured to receive the current oil temperature of the transmission and calculate the clutch maximum oil discharge time threshold at the current oil temperature based on the current oil temperature. The clutch maximum oil discharge time threshold calculation unit is connected to the clutch state determination unit;

[0037] And a zero-drift adaptive unit, configured to use the current pressure sensor voltage value as the zero voltage value of the pressure sensor when it is detected that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature. The zero-drift adaptive unit is connected to the clutch maximum oil discharge time threshold calculation unit.

[0038] In a fourth aspect, a system for calculating the effective acting pressure of a clutch according to the present invention includes:

[0039] A clutch state determination unit, configured to determine whether the clutch enters an oil discharge state, and when it is determined that the state of the clutch is oil discharge, trigger a clutch oil discharge timer to measure the oil discharge time of the clutch;

[0040] A clutch maximum oil discharge time threshold calculation unit, configured to receive the current oil temperature of the transmission and calculate the clutch maximum oil discharge time threshold at the current oil temperature based on the current oil temperature. The clutch maximum oil discharge time threshold calculation unit is connected to the clutch state determination unit;

[0041] A zero drift adaptive unit, configured to use the current pressure sensor voltage value as the zero voltage value of the pressure sensor when it is detected that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature. The zero drift adaptive unit is connected to the clutch maximum oil discharge time threshold calculation unit;

[0042] And a clutch effective acting pressure calculation unit, configured to calculate the clutch effective acting pressure P according to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out The clutch effective acting pressure calculation unit is connected to the zero drift adaptive unit.

[0043] Optionally, the calculation method of the clutch effective acting pressure P is:

[0044] P = (V out - V0) / K;

[0045] Wherein, K is a voltage-pressure conversion factor, and V0 is the zero voltage value of the pressure sensor.

[0046] In a fifth aspect, a vehicle according to the present invention adopts the pressure sensor zero drift adaptive system as described in the present invention.

[0047] In a sixth aspect, a vehicle according to the present invention adopts the clutch effective acting pressure calculation system as described in the present invention.

[0048] In a seventh aspect, a storage medium according to the present invention stores a computer-readable program, and when the computer-readable program is called, it can execute the steps of the pressure sensor zero drift adaptive method as described in the present invention.

[0049] In an eighth aspect, a storage medium according to the present invention stores a computer-readable program, and when the computer-readable program is called, it can execute the steps of the clutch effective acting pressure calculation method as described in the present invention.

[0050] The present invention has the following advantages:

[0051] (1) Combining the characteristics of a wet dual-clutch transmission, the present invention proposes a simpler and more effective zero-drift adaptive method for pressure sensors, which can accurately adapt to the zero-drift of pressure sensors in a timely manner, greatly improving the calculation accuracy of the effective acting pressure of the clutch, and significantly enhancing the low-speed performance of the whole vehicle, especially the crawling and starting performance, thus greatly improving the ride comfort of the vehicle.

[0052] (2) The present invention effectively avoids the influence of the external environment, wiring harness, connectors, TCU, and the hardware characteristics of the sensor itself on the zero-drift calculation, greatly improving the calculation accuracy of the effective acting force of the clutch. At the same time, it reduces the requirements for the hardware consistency of the sensor, significantly improving the qualified rate of the pressure sensor, thereby reducing the cost of the pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0054] Figure 1 It is a schematic diagram of the oil circuit of the wet dual-clutch transmission in the present invention;

[0055] Figure 2 It is an example of the pressure-voltage characteristic curve of the pressure sensor in the present invention;

[0056] Figure 3 It is a principle block diagram of Embodiment 1 in the present invention;

[0057] Figure 4 It is a flowchart of Embodiment 1 in the present invention;

[0058] Figure 5 It is a principle block diagram of Embodiment 2 in the present invention;

[0059] Figure 6 It is a flowchart of Embodiment 2 in the present invention;

[0060] In the figure: 1, power source; 2, pressure control solenoid valve; 3, pressure sensor; 4, wet clutch driving piston; 5, clutch oil passage; 6, clutch state judgment unit; 7, clutch maximum oil discharge time threshold calculation unit; 8, zero-drift adaptive unit; 9, clutch effective acting pressure calculation unit. DETAILED DESCRIPTION OF THE INVENTION

[0061] Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not used to limit the protection scope of the present application.

[0062] It should be noted that the modifiers "a" and "multiple" mentioned in the present application are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly specified in the context, it should be understood as "one or more".

[0063] Embodiment 1

[0064] Figure 1 As shown, it is a schematic diagram of the hydraulic oil circuit of the wet clutch in this embodiment. The hydraulic oil circuit of the wet clutch includes a power source 1, a pressure control solenoid valve 2, a pressure sensor 3, a wet clutch driving piston 4, and a clutch oil passage 5. Among them, the power source 1 provides the inlet pressure and flow rate for the pressure control solenoid valve 2. When the clutch is working, the pressure control solenoid valve 2 controls the pressure in the clutch oil passage 5. When the clutch is not working, the pressure oil in the clutch oil passage 5 will be drained back to the gearbox through the oil return port of the pressure control solenoid valve 2. At this time, the pressure in the clutch oil passage 5 is the same as the internal ambient air pressure of the gearbox. The pressure sensor 3 is located at the outlet of the pressure control solenoid valve 2 in the clutch oil passage 5 and monitors the pressure in the clutch driving piston chamber in real time. The wet clutch driving piston 4 is used to drive the engagement and separation of the clutch discs. From Figure 1 It can be seen that after the clutch is drained of oil, the electrical value of the pressure sensor 3 is the internal air pressure value of the gearbox, that is, the zero drift value of the pressure sensor.

[0065] As Figure 2 shown, it is a characteristic curve graph of the absolute pressure sensor in this embodiment. The supply voltage of the pressure sensor is 5V. As Figure 2 shown in, when the absolute pressure is 1 standard atmospheric pressure, the theoretical voltage output value of the pressure sensor is 0.5V. In fact, the voltage output value of the mass-produced pressure sensor at this time may be between 0.44V and 0.52V, and the error range is quite large. Therefore, it is very necessary to adapt each pressure sensor.

[0066] In this embodiment, a method for zero drift adaptation of a pressure sensor includes the following steps:

[0067] In response to determining that the state of the clutch is oil drainage, trigger the clutch oil drainage timer to time the oil drainage time of the clutch;

[0068] Obtain the current oil temperature of the transmission and calculate the maximum oil discharge time threshold of the clutch at the current oil temperature;

[0069] In response to detecting that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature, it is determined that the oil discharge of the clutch is completed, and the current pressure sensor voltage value is used as the zero voltage value of the pressure sensor.

[0070] As Figure 4 shown, in this embodiment, a method for self - adapting to zero drift of the pressure sensor is as follows:

[0071] Step 1: Determine whether the state of the clutch is oil discharge. If so, go to Step 2; if not, continue to execute Step 1;

[0072] Step 2: Trigger the clutch oil discharge calculator to start oil discharge timing; obtain the current oil temperature of the transmission and calculate the maximum oil discharge time threshold of the clutch at the current oil temperature;

[0073] Step 3: Determine whether the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature. If so, go to Step 4; if not, wait and continue to execute Step 3;

[0074] Step 4: Use the current pressure sensor voltage value as the zero voltage value of the pressure sensor.

[0075] In this embodiment, to determine whether the clutch enters the oil discharge state, specifically:

[0076] Determine whether all the following conditions are satisfied. If so, it means the clutch enters the oil discharge state; otherwise, it means the clutch does not enter the oil discharge state;

[0077] 1) The clutch torque request is 0, determining that there is no torque control requirement for the clutch;

[0078] 2) The clutch pressure request is 0, determining that there is no pressure control requirement for the clutch;

[0079] 3) The clutch output command pressure is 0, determining that the clutch pressure control valve does not output command pressure;

[0080] 4) The clutch current request is 0, determining that there is no current request for the clutch pressure control valve;

[0081] 5) The actual current of the clutch is 0, determining that the clutch pressure control valve is in the closed state and the clutch oil passage discharges oil through the control valve;

[0082] 6) The change rate of the clutch pressure sensor voltage value is less than the set voltage threshold, determining that the clutch has entered a stable oil discharge process. The voltage threshold in this embodiment is preferably set to 10mv.

[0083] This method uses the judgment of whether the clutch is in a non-operating state and whether the clutch oil drainage is completed as the trigger condition for the zero-drift adaptation of the pressure sensor. Therefore, it is not affected by external environments such as altitude and atmospheric pressure. The calculation method is simple and reliable, and it can adapt to the air pressure changes in the gearbox efficiently and promptly.

[0084] In this embodiment, calculate the maximum oil drainage time threshold of the clutch at the current oil temperature, specifically:

[0085] Look up the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures through the current oil temperature of the transmission to obtain the maximum oil drainage time threshold of the clutch at the current oil temperature.

[0086] In this embodiment, the method for obtaining the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures is as follows:

[0087] Test the oil drainage time of multiple clutches at different oil temperatures;

[0088] Take the maximum value of the oil drainage time of each clutch at the same oil temperature as the maximum oil drainage time of the clutch at that oil temperature;

[0089] Correspond the maximum oil drainage time and the oil temperature one by one to form the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures.

[0090] In this embodiment, the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures is stored in the TCU memory. When the clutch oil drainage is completed, the clutch oil passage is connected to the atmosphere inside the gearbox. At this time, the pressure value detected by the pressure sensor is the internal air pressure of the gearbox, that is, the zero-drift value of the pressure sensor. In order to avoid the influence of the residual oil pressure in the clutch oil passage on the zero-point voltage value of the pressure sensor, it is necessary to ensure that the clutch has completed oil drainage before performing the zero-drift adaptation of the pressure sensor. The main factor affecting the clutch oil drainage process is the oil temperature. Therefore, it is necessary to test the oil drainage time of the clutch at different oil temperatures. In addition, due to manufacturing and assembly errors, different clutches have different oil drainage times. The oil drainage time curves of multiple clutch samples can be tested, and the maximum value of the oil drainage time among all test samples is taken as the maximum oil drainage time of the clutch.

[0091] For example, in a certain production vehicle, the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures is shown in Table 1 (unit: ms):

[0092]

[0093] In this embodiment, before using the current pressure sensor voltage value as the zero voltage value of the pressure sensor, the voltage signal of the pressure sensor is subjected to time-domain average filtering, and the filtered sensor voltage value is recorded as the zero voltage value of the pressure sensor and stored in the TCU memory. The time-domain average filtering refers to performing average filtering on the pressure sensor voltage values within 5 consecutive TCU task cycles to improve the accuracy of the zero voltage value.

[0094] As Figure 3 shown, in this embodiment, a pressure sensor zero-drift adaptive system includes a clutch state determination unit 6, a clutch maximum oil discharge time threshold calculation unit 7, and a zero-drift adaptive unit 8. Among them, the clutch state determination unit 6 is used to determine whether the clutch enters the oil discharge state, and when it is determined that the state of the clutch is oil discharge, it triggers a clutch oil discharge timer to time the oil discharge time of the clutch. The clutch maximum oil discharge time threshold calculation unit 7 is used to receive the current oil temperature of the transmission and calculate the clutch maximum oil discharge time threshold at the current oil temperature. The clutch maximum oil discharge time threshold calculation unit 7 is connected to the clutch state determination unit 6. The zero-drift adaptive unit 8 is used to use the current pressure sensor voltage value as the zero voltage value of the pressure sensor when it detects that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature. The zero-drift adaptive unit 8 is connected to the clutch maximum oil discharge time threshold calculation unit 7.

[0095] In view of the deficiencies of the existing solutions and combined with the characteristics of the wet dual-clutch transmission, the present invention proposes a simpler and more effective pressure sensor zero-drift adaptive method, which can accurately adapt to the zero drift of the sensor in a timely manner.

[0096] In this embodiment, a vehicle adopts the pressure sensor zero-drift adaptive system as described in this embodiment.

[0097] In this embodiment, a storage medium stores a computer-readable program, and when the computer-readable program is called, it can execute the steps of the pressure sensor zero-drift adaptive method as described in this embodiment.

[0098] Embodiment 2

[0099] In this embodiment, a method for calculating the effective acting pressure of a clutch includes the following steps:

[0100] When it is determined that the state of the clutch is oil discharge, trigger a clutch oil discharge timer to time the oil discharge time of the clutch;

[0101] Obtain the current oil temperature of the transmission and calculate the clutch maximum oil discharge time threshold at the current oil temperature;

[0102] In response to detecting that the oil drain time of the clutch is greater than the maximum oil drain time threshold at the corresponding temperature, it is determined that the clutch oil drain is completed, and the current pressure sensor voltage value is used as the zero voltage value of the pressure sensor;

[0103] Obtain the voltage value V output by the pressure sensor out ;

[0104] According to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out Calculate the effective acting pressure P of the clutch.

[0105] In this embodiment, according to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out Calculate the effective acting pressure P of the clutch, specifically:

[0106] P = (V out - V0) / K;

[0107] Wherein, K is the voltage-pressure conversion factor, and V0 is the zero voltage value of the pressure sensor.

[0108] As Figure 6 shown, in this embodiment, a method for calculating the effective acting pressure of a clutch is as follows:

[0109] Step 1. Determine whether the state of the clutch is oil drain. If so, go to Step 2; if not, continue to execute Step 1;

[0110] Step 2. Trigger the clutch oil drain calculator to start oil drain timing; obtain the current oil temperature of the transmission and calculate the maximum oil drain time threshold of the clutch at the current oil temperature;

[0111] Step 3. Determine whether the oil drain time of the clutch is greater than the maximum oil drain time threshold at the corresponding temperature. If so, go to Step 4; if not, wait and continue to execute Step 3;

[0112] Step 4. Use the current pressure sensor voltage value as the zero voltage value of the pressure sensor;

[0113] Step 5. Obtain the voltage value output by the pressure sensor;

[0114] Step 6. According to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out Calculate the effective acting pressure P of the clutch, that is, the effective acting pressure acting on the clutch plate.

[0115] As Figure 5As shown in the figure, in this embodiment, a calculation system for the effective acting pressure of a clutch includes a clutch state determination unit 6, a clutch maximum oil discharge time threshold calculation unit 7, a zero-drift adaptive unit 8, and a clutch effective acting pressure calculation unit 9. Among them, the clutch state determination unit 6 is used to determine whether the clutch enters the oil discharge state, and when it is determined that the state of the clutch is oil discharge, trigger a clutch oil discharge timer to time the oil discharge time of the clutch. The clutch maximum oil discharge time threshold calculation unit 7 is used to receive the current oil temperature of the transmission and calculate the clutch maximum oil discharge time threshold at the current oil temperature based on the current oil temperature. The clutch maximum oil discharge time threshold calculation unit 7 is connected to the clutch state determination unit 6. The zero-drift adaptive unit 8 is used to use the current pressure sensor voltage value as the zero voltage value of the pressure sensor when it is detected that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature. The zero-drift adaptive unit 8 is connected to the clutch maximum oil discharge time threshold calculation unit 7. The clutch effective acting pressure calculation unit 9 is used to calculate the clutch effective acting pressure P according to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out The clutch effective acting pressure calculation unit 9 is connected to the zero-drift adaptive unit 8.

[0116] In view of the deficiencies of the existing solutions and combined with the characteristics of the wet dual-clutch transmission, the present invention proposes a simpler and more effective pressure sensor zero-drift adaptive method, which can accurately adapt to the zero drift of the sensor in a timely manner, greatly improving the calculation accuracy of the clutch effective acting pressure. The low-speed performance of the whole vehicle, especially the crawling and starting performance, has been greatly improved. At the same time, this method effectively avoids the influence of hardware differences such as sensors, wiring harnesses, connectors, and TCU controllers on the zero electrical value of the sensor, reduces the requirements for hardware consistency, and can effectively reduce the hardware cost.

[0117] In this embodiment, a vehicle adopts the clutch effective acting pressure calculation system described in this embodiment.

[0118] In this embodiment, a storage medium stores a computer-readable program, and when the computer-readable program is called, it can execute the steps of the clutch effective acting pressure calculation method described in this embodiment.

[0119] In this embodiment, the rest is the same as that in Embodiment 1.

[0120] In the context of the present application, a machine-readable medium can be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0121] As used in this embodiment, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, apparatus, and / or device (e.g., a disk, an optical disk, a memory, a programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0122] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A zero-drift self-adaptive method for a pressure sensor, characterized in that, It includes the following steps: When it is determined that the state of the clutch is oil drainage, trigger the clutch oil drainage timer to time the oil drainage time of the clutch; Obtain the current oil temperature of the transmission and calculate the maximum oil drainage time threshold of the clutch at the current oil temperature; When it is detected that the oil drainage time of the clutch is greater than the maximum oil drainage time threshold at the corresponding temperature, use the current pressure sensor voltage value as the zero-point voltage value of the pressure sensor; Calculate the maximum oil drainage time threshold of the clutch at the current oil temperature, specifically: Look up the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures through the current oil temperature of the transmission to obtain the maximum oil drainage time threshold of the clutch at the current oil temperature; The method for obtaining the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures is as follows: Test the oil drainage time of multiple clutch samples at different oil temperatures; Take the maximum value of the oil drainage time of each clutch sample at the same oil temperature as the maximum oil drainage time of the clutch at that oil temperature; Form the corresponding relationship table of the maximum oil drainage time of the clutch at different oil temperatures by corresponding the maximum oil drainage time and the oil temperature one by one.

2. The zero-drift self-adaptive method of the pressure sensor according to claim 1, characterized in that: Judge whether the clutch enters the oil drainage state, specifically: Judge whether the following conditions are all met. If so, it means that the clutch enters the oil drainage state; otherwise, it means that the clutch does not enter the oil drainage state; 1) The clutch has no torque control requirement; 2) The clutch has no pressure control requirement; 3) The clutch pressure control valve does not output the command pressure; 4) The clutch pressure control valve has no current request; 5) The clutch pressure control valve is in the closed state, and the clutch oil passage drains oil through the control valve; 6) The change rate of the clutch pressure sensor voltage value is less than the set voltage threshold.

3. The zero-drift self-adaptive method of the pressure sensor according to claim 1, wherein: Before using the current pressure sensor voltage value as the zero-point voltage value of the pressure sensor, perform time-domain average filtering on the voltage signal of the pressure sensor, and record the filtered sensor voltage value as the zero-point voltage value of the pressure sensor.

4. A method for calculating the effective acting pressure of a clutch, characterized in that, It includes the following steps: Obtain the zero-point voltage value of the pressure sensor by using the pressure sensor zero-drift adaptive method described in any one of claims 1 to 3; Obtain the voltage value V output by the pressure sensor out ; According to the zero voltage value of the pressure sensor and the voltage value V output by the pressure sensor out calculate the effective acting pressure P of the clutch.

5. The method for calculating the effective acting pressure of the clutch according to claim 4, wherein: The calculation method of the effective acting pressure P of the clutch is: P = (V out - V0) / K where K is the voltage-pressure conversion factor and V0 is the zero-point voltage value of the pressure sensor.

6. A zero-drift adaptive system for a pressure sensor, characterized in that It includes: A clutch state judgment unit (6) for determining whether the clutch enters the oil drainage state, and when it is determined that the state of the clutch is oil drainage, triggering the clutch oil drainage timer to time the oil drainage time of the clutch; A clutch maximum oil drainage time threshold calculation unit (7) for receiving the current oil temperature of the transmission and calculating the maximum oil drainage time threshold of the clutch at the current oil temperature based on the current oil temperature. The clutch maximum oil drainage time threshold calculation unit (7) is connected to the clutch state judgment unit (6); And a zero-drift adaptive unit (8) for using the current pressure sensor voltage value as the zero-point voltage value of the pressure sensor when it is detected that the oil drainage time of the clutch is greater than the maximum oil drainage time threshold at the corresponding temperature. The zero-drift adaptive unit (8) is connected to the clutch maximum oil drainage time threshold calculation unit (7); Among them, calculating the maximum oil drainage time threshold of the clutch at the current oil temperature, specifically: Look up the corresponding relationship table of the maximum oil discharge time of the clutch at different oil temperatures based on the current oil temperature of the transmission to obtain the maximum oil discharge time threshold of the clutch at the current oil temperature; The method for obtaining the corresponding relationship table of the maximum oil discharge time of the clutch at different oil temperatures is as follows: Test the oil discharge time of multiple clutch samples at different oil temperatures; Take the maximum value of the oil discharge time of each clutch sample at the same oil temperature as the maximum oil discharge time of the clutch at that oil temperature; Correspond the maximum oil discharge time and the oil temperature one by one to form the corresponding relationship table of the maximum oil discharge time of the clutch at different oil temperatures.

7. A clutch effective acting pressure calculation system, characterized in that It includes: A clutch state judgment unit (6) for determining whether the clutch enters the oil discharge state, and when it is determined that the state of the clutch is oil discharge, triggering the clutch oil discharge timer to time the oil discharge time of the clutch; A clutch maximum oil discharge time threshold calculation unit (7) for receiving the current oil temperature of the transmission and calculating the maximum oil discharge time threshold of the clutch at the current oil temperature based on the current oil temperature. The clutch maximum oil discharge time threshold calculation unit (7) is connected to the clutch state judgment unit (6); A zero drift adaptive unit (8) for, when detecting that the oil discharge time of the clutch is greater than the maximum oil discharge time threshold at the corresponding temperature, taking the current pressure sensor voltage value as the zero voltage value of the pressure sensor. The zero drift adaptive unit (8) is connected to the clutch maximum oil discharge time threshold calculation unit (7); and a clutch effective acting pressure calculation unit (9) for calculating a clutch effective acting pressure P according to a zero voltage value of a pressure sensor and a voltage value V output by the pressure sensor, and the clutch effective acting pressure calculation unit (9) is connected to a zero drift adaptive unit (8); out ​ Among them, calculating the maximum oil discharge time threshold of the clutch at the current oil temperature specifically means: Look up the corresponding relationship table of the maximum oil discharge time of the clutch at different oil temperatures based on the current oil temperature of the transmission to obtain the maximum oil discharge time threshold of the clutch at the current oil temperature; The method for obtaining the corresponding relationship table of the maximum oil discharge time of the clutch at different oil temperatures is as follows: Test the oil discharge time of multiple clutch samples at different oil temperatures; Take the maximum value of the oil discharge time of each clutch sample at the same oil temperature as the maximum oil discharge time of the clutch at that oil temperature; Correspond the maximum oil discharge time and the oil temperature one by one to form the corresponding relationship table of the maximum oil discharge time of the clutch at different oil temperatures.

8. The clutch effective acting pressure calculation system according to claim 7, characterized in that: The calculation method of the effective acting pressure P of the clutch is: P = (V out - V0) / K; Among them, K is the voltage-pressure conversion factor, and V0 is the zero voltage value of the pressure sensor.

9. A vehicle, characterized in that: Adopt the pressure sensor zero drift adaptive system as described in claim 6.

10. A vehicle, characterized in that: Adopt the clutch effective acting pressure calculation system as described in claim 7 or 8.

11. A storage medium, characterized in that: It stores a computer-readable program, and when the computer-readable program is called, it can execute the steps of the pressure sensor zero drift adaptive method as described in any one of claims 1 to 3.

12. A storage medium, characterized in that: It stores a computer-readable program, and when the computer-readable program is called, it can execute the steps of the clutch effective acting pressure calculation method as described in claim 4 or 5.

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