A displacement detection method and a flow detection method

Abstract

The present disclosure relates to a displacement detection method and a flow detection method. Among them, the displacement detection method is used to detect the displacement of the solenoid valve used for thermal management, including: sampling the current flowing through the solenoid valve; calculating the rate of change of the current flowing through the solenoid valve in a unit time period; calculating the average value of the voltage applied to the solenoid valve in the unit time period; determining the inductance of the solenoid valve in the unit time period; and obtaining the displacement of the solenoid valve in the unit time period. The displacement detection method proposed in the present disclosure can detect the displacement of the solenoid valve without setting up additional sensors, thereby further simplifying the hardware structure of the thermal management system that uses solenoid valves to achieve thermal management and saving costs. In addition, the flow detection method proposed in the present disclosure can improve the thermal management efficiency and accuracy of the thermal management system that uses solenoid valves to achieve thermal management, and save costs.

Description

Technical Field

[0001] The present disclosure relates to the field of thermal management technology, and in particular to a displacement detection method and a flow detection method. Background Art

[0002] According to market research, more efficient hybrid engine systems or pure electric engine systems are required in the near future. Therefore, thermal management systems will become increasingly important in conventional hybrid engine systems or pure electric engine systems. Currently, there is a thermal management system that uses a solenoid valve to distribute the flow of fluid flowing in a pipeline to achieve thermal management. Since the thermal management system has a low cost and a simple structure, it can be applied to various engine transmission systems.

[0003] In order to perform thermal management more effectively, it is necessary to grasp the actual state of the solenoid valve in real time, such as the displacement of the solenoid valve. In addition, a position sensor or a displacement sensor having a primary coil and a secondary coil is generally used to detect the displacement of the solenoid valve. However, this method of detecting the displacement of the solenoid valve has the following disadvantages:

[0004] 1-1. Setting up sensors will incur additional costs;

[0005] 1-2. Additional space is required to configure and install the sensor, which increases the size of the vehicle;

[0006] 1-3. Additional wiring harnesses are required to connect sensors, increasing the functional risk of the vehicle and causing increased wiring weight;

[0007] 1-4. It is necessary to consider the sensor structure strength, reliability and failure mode of the sensor itself, which increases the difficulty and complexity of the design;

[0008] 1-5. Limit the application scope of low-cost thermal management systems driven by solenoid valves.

[0009] In addition, in order to perform thermal management more effectively, it is sometimes necessary to grasp the actual flow rate of the fluid flowing in the pipeline controlled by the solenoid valve in real time. Although the current thermal management system can accurately distribute the flow rate, it cannot estimate the actual flow rate. In other words, the existing low-cost thermal management system driven by solenoid valves has the following disadvantages:

[0010] 2-1. It is impossible to estimate the actual flow rate of the fluid flowing in the pipeline at a certain opening of the solenoid valve, or the actual flow distribution in the pipeline;

[0011] 2-2. The flow controllability of existing products using the solenoid valve concept is not linear, and there is a sharp flow deviation;

[0012] 2-3. The outsourced actuator accounts for 50% to 60% of the BOM cost, and it only provides angle signals to the ECU and is passively controlled;

[0013] 2-4. The existing switch type solenoid valve adjusts the solenoid valve to switch the flow only when the acquired temperature is overheated. This switch function can only be calibrated by a large amount of manual calibration to calibrate the flow direction of the solenoid valve. Summary of the invention

[0014] In view of this, the present disclosure proposes a displacement detection method that can minimize or even completely eliminate at least one of the above-mentioned shortcomings 1-1 to 1-5, and a flow detection method that can minimize or even completely eliminate at least one of the above-mentioned shortcomings 2-1 to 2-4.

[0015] In order to minimize or even completely eliminate at least one of the above-mentioned shortcomings 1-1 to 1-5, according to one aspect of the present disclosure, a displacement detection method is provided for detecting the displacement of a solenoid valve used for thermal management, wherein the solenoid valve comprises a coil and a magnetic core, and by applying a voltage having a specific duty cycle to the coil, the magnetic core can be displaced to control the fluid flowing in the pipeline in which the solenoid valve is provided, thereby achieving the thermal management, and characterized in that the displacement detection method comprises: sampling the current flowing through the coil; calculating the rate of change di / dt of the current flowing through the coil in a unit time period between a first moment T0 and a second moment T1 after a unit time Δt has passed since the first moment T0; and calculating the average value U of the voltage applied to the coil in the unit time period. ave ; According to the rate of change of the current di / dt and the average value of the voltage U ave , determine the inductance L of the coil in the unit time period; and obtain the displacement D of the magnetic core relative to the reference position in the unit time period based on the inductance L of the coil, and use it as the displacement D of the solenoid valve in the unit time period.

[0016] For the above-mentioned displacement detection method, in a possible implementation, the current flowing through the coil is sampled in real time, and the sampled current is smoothed, and the smoothed current is used to calculate the rate of change di / dt of the current in each unit time period, thereby obtaining the displacement D of the solenoid valve in each unit time period.

[0017] For the above displacement detection method, in a possible implementation manner, it also includes: sending the obtained displacement D of the solenoid valve in each unit time period to a control device for performing the thermal management in real time.

[0018] For the above displacement detection method, in a possible implementation, the inductance L of the coil in the unit time period is determined using formula (1):

[0019] L=(U ave -i0R)(di / dt) -1 (1)

[0020] Herein, i0 represents the current flowing through the coil at the first moment T0, and R represents the resistance of the coil.

[0021] For the above displacement detection method, in a possible implementation, formula (2) is used to obtain the displacement D of the magnetic core relative to the reference position within the unit time period:

[0022]

[0023] Wherein, μ represents the relative magnetic permeability of the magnetic core, N represents the number of turns of the coil, and S represents the effective cross-sectional area of ​​the solenoid valve.

[0024] In order to minimize or even completely eliminate at least one of the above-mentioned shortcomings 2-1 to 2-4, according to another aspect of the present disclosure, a flow detection method is provided for detecting the flow rate of a fluid flowing in a pipeline controlled by a solenoid valve, characterized in that it comprises: detecting the displacement D of the solenoid valve in a unit time period by using the displacement detection method described in any one of claims 1 to 5; determining the opening S of the pipeline in the unit time period according to the displacement D of the solenoid valve. slot ; and according to the opening S of the pipeline slot and the velocity v of the fluid flowing to the pipeline in the unit time period, determine the flow rate Q of the fluid flowing in the pipeline in the unit time period.

[0025] For the above flow detection method, in a possible implementation, it also includes: pre-establishing the displacement D of the solenoid valve and the opening S of the pipeline slot The relationship between them is shown in formula (3):

[0026] S slot =F(D) (3)

[0027] Wherein, the opening S of the pipeline in the unit time period is determined by formula (3): slot .

[0028] For the above flow detection method, in a possible implementation, it also includes: using formula (4) to calculate the velocity v of the fluid flowing to the pipeline:

[0029]

[0030] Wherein, P′ represents the pressure on the equivalent cross-sectional area of ​​the magnetic core of the solenoid valve, P represents the pressure near the equivalent cross-sectional area, and ρ represents the density of the fluid.

[0031] For the above-mentioned flow detection method, in a possible implementation, it also includes: determining the flow rate Q of the fluid flowing in the pipeline in each unit time period, and sending the determined flow rate Q of the fluid flowing in the pipeline in each unit time period in real time to the control device used to perform the thermal management.

[0032] By detecting the displacement of the magnetic core relative to the reference position within a certain time period based on the rate of change of the current flowing through the coil within the time period, the displacement detection method proposed in the present invention can detect the displacement of the solenoid valve without setting up an additional sensor, thereby further simplifying the hardware structure of the thermal management system that uses the solenoid valve to achieve thermal management and saving costs.

[0033] On the other hand, the flow detection method proposed in the present disclosure can detect the flow rate of the fluid flowing in the pipeline controlled by the solenoid valve based on the displacement of the magnetic core relative to the reference position within a certain time period. Therefore, it can improve the thermal management efficiency and accuracy of the thermal management system that uses the solenoid valve to achieve thermal management and save costs.

[0034] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0036] Figure 1 A schematic diagram showing the structure of the solenoid valve used in thermal management;

[0037] Figure 2 A flow chart showing a displacement detection method according to an embodiment of the present disclosure;

[0038] Figure 3 A waveform schematic diagram showing smoothing of the sampled current according to an embodiment of the present disclosure;

[0039] Figure 4 A schematic diagram showing a possible implementation of a displacement detection method according to an embodiment of the present disclosure;

[0040] Figure 5 A schematic diagram showing an experimental result of a displacement detection method according to an embodiment of the present disclosure;

[0041] Figure 6 Another schematic diagram showing an experimental result of a displacement detection method according to an embodiment of the present disclosure;

[0042] Figure 7 A schematic diagram showing another experimental result of a displacement detection method according to an embodiment of the present disclosure;

[0043] Figure 8 A schematic diagram showing the principle of a flow detection method according to an embodiment of the present disclosure;

[0044] Fig. 9 A flow chart showing a flow detection method according to an embodiment of the present disclosure is shown;

[0045] Fig.10 A schematic diagram showing a possible implementation of a flow detection method according to an embodiment of the present disclosure;

[0046] Fig.11 A schematic diagram showing a possible application of a flow detection method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0047] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0048] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0049] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0050] Example 1

[0051] The displacement detection method according to an embodiment of the present disclosure is used to detect the displacement of a solenoid valve used in thermal management. Figure 1 As shown, the solenoid valve mainly includes a coil 10 and a magnetic core 20, and by applying a voltage with a specific duty cycle to the coil 10 via the connecting pin 30 of the solenoid valve, the magnetic core 20 can be displaced to control the fluid flowing in the pipeline in which the solenoid valve is set, thereby realizing the thermal management.

[0052] like Figure 2 As shown, the displacement detection method mainly includes steps S100 to S500. In step S100, the current flowing through the coil 10 is sampled. In a possible implementation, the current flowing through the coil 10 can be sampled in real time, and the sampled current can be smoothed by an appropriate coefficient until the slope of the smoothed current is very close to the total gradient of the original current.

[0053] For example, Figure 3 As shown, the slope of the entire smooth current is completely different from the optimal slope zone of the smooth current. The optimal slope zone of the smooth current can be distinguished by the following principle and idea, so as to ensure that the slope of the smooth current used subsequently is in the optimal slope zone. Among them, the starting point of the optimal slope zone of the smooth current is turning point 2, and the turning point 2 is processed by a real-time algorithm such as a bandpass filter. The end point of the optimal slope zone of the smooth current is turning point 3, and the turning point 3 is continuously calculated by the derivative pole of the smooth current curve. Once the optimal slope zone is determined, the slope of the smooth current in the optimal slope zone can be calculated.

[0054] In step S200, the change rate di / dt of the current flowing through the coil 10 in a unit time period between a first moment T0 and a second moment T1 after a unit time Δt has passed since the first moment T0 is calculated. In the case where the sampled voltage is smoothed, the change rate di / dt of the current in each unit time period can be calculated using the smoothed current. For example, the smoothed current can be resampled. Figure 4 As shown, assuming that the resampling points of the smoothed current are the first moment T0 and the second moment T1, and the current flowing through the coil 10 at the first moment T0 is i0, and the current flowing through the coil 10 at the second moment T1 is i1, it can be considered that within the unit time period between the first moment T0 and the second moment T1, the rate of change of the current flowing through the coil 10 is di / dt=(i1-i0) / Δt.

[0055] In step S300, the average value U of the voltage applied to the coil 10 in the unit time period is calculated. ave In one possible implementation, the voltage applied to the coil 10 is sampled in real time and synchronized with the resampling of the smoothed current. Figure 4 As shown, assuming that the voltage applied to the coil 10 at the first moment T0 is u0, and the voltage applied to the coil 10 at the second moment T1 is u1, it can be considered that the average value U of the voltage applied to the coil 10 in the unit time period between the first moment T0 and the second moment T1 is ave =(u1+u0) / 2.

[0056] In step S400, according to the current change rate di / dt and the voltage average value U ave , determine the inductance L of the coil 10 in the unit time period. In a possible implementation, the inductance L of the coil 10 in the unit time period can be determined using formula (1):

[0057] L=(U ave -i0R)(di / dt) -1 (1)

[0058] As described above, i0 represents the current flowing through the coil 10 at the first moment T0 , and R represents the resistance of the coil 10 .

[0059] In step S500, the displacement D of the magnetic core 20 relative to the reference position in the unit time period is obtained according to the inductance L of the coil 10, and is used as the displacement D of the solenoid valve in the unit time period. In a possible implementation, the displacement D of the magnetic core 20 relative to the reference position in the unit time period can be obtained using formula (2):

[0060]

[0061] Wherein, μ represents the relative magnetic permeability of the magnetic core 20 , N represents the number of turns of the coil 10 , and S represents the effective cross-sectional area of ​​the solenoid valve.

[0062] In a possible implementation, the displacement detection method of an embodiment of the present disclosure may also include: sending the obtained displacement D of the solenoid valve in each unit time period to a control device for performing the thermal management, such as an ECU, in real time. In this way, the ECU can grasp the actual state of the solenoid valve in real time, so that thermal management can be performed more effectively. In addition, the ECU can also display the data in real time on the main screen of the vehicle to facilitate the driver to understand the current state of the vehicle during driving.

[0063] Of course, the focus of the displacement detection method disclosed in the present invention is to propose a technical concept that can detect the displacement of the solenoid valve without setting up a special sensor. Therefore, as to how to use the obtained displacement of the solenoid valve, those skilled in the art can decide according to the actual application scenario. The present disclosure does not make too much explanation on this, nor does it make any limitation.

[0064] It should also be noted that, although a possible method of implementing steps S200 to S500 is exemplified above with a specific calculation formula, the present disclosure is not limited thereto. A method provided by those skilled in the art in the present disclosure may be based on the rate of change di / dt of the current flowing through the coil in a unit time period and the average value U of the voltage applied to the coil in the unit time period.ave Inspired by the idea of ​​directly calculating the displacement of the solenoid valve without setting up a sensor, based on the basic knowledge, other methods should be able to be used to implement the above steps S200 to S500. In other words, there are many ways to implement steps S200 to S500, and this disclosure cannot list them all. However, as long as steps S200 to S500 are used to detect the displacement of the solenoid valve, they all fall within the scope of protection of this disclosure.

[0065] Several sets of experimental data are used below to verify the feasibility of the displacement detection method disclosed in the present invention.

[0066] Assuming that a pulse width modulation voltage with a frequency of 130 Hz and a duty cycle of 50% is applied to the coil 10 of the solenoid valve at room temperature, a constant current with an average value of 0.75 A will be generated. Under the action of the generated electromagnetic force and the fluid force in the pipeline, the magnetic core of the solenoid valve may remain in the initial position, or may be moved to the end position farthest from the initial position, or to a certain intermediate position between the initial position and the end position. Among them, when the magnetic core of the solenoid valve is at the end position, it can be considered that the solenoid valve makes the opening of the pipeline minimum, and the displacement of the solenoid valve is maximum. When the magnetic core of the solenoid valve is at the initial position, it can be considered that the solenoid valve makes the opening of the pipeline maximum, and the displacement of the solenoid valve is minimum. When the magnetic core of the solenoid valve is at the middle position, it can be considered that the solenoid valve makes the opening of the pipeline between the minimum and the maximum, and the displacement of the solenoid valve is also between the minimum and the maximum.

[0067] like Figure 5 As shown in FIG. 1 , when the magnetic core of the solenoid valve is located at these three positions, the peak-to-peak value of the current detected from the solenoid valve is different. Specifically, Figure 6 As shown in the figure, the current change rate is the smallest when the magnetic core of the solenoid valve is at the end position, the current change rate is the second largest when the magnetic core of the solenoid valve is at the middle position, and the current change rate is the largest when the magnetic core of the solenoid valve is at the initial position. In other words, the current change rate decreases as the displacement of the solenoid valve increases. In other words, the displacement of the solenoid valve is inversely proportional to the current change rate.

[0068] It can be seen that the position of the magnetic core of the solenoid valve can be reflected from the rate of change of the current of the solenoid valve. Therefore, the displacement D of the magnetic core relative to the reference position in a certain period of time can be obtained according to the rate of change of the current flowing through the coil in the period of time.

[0069] The above is an explanation of the corresponding relationship between the position of the magnetic core and the current change rate when the duty cycle of the pulse width modulation voltage applied to the solenoid valve is 50% at room temperature. The following will study the current change rate when the magnetic core is in the same position by changing the duty cycle of the pulse width modulation voltage. Figure 7 As shown in the figure, when a pulse width modulation voltage with a duty cycle of 50% and 57% is applied to the solenoid valve at room temperature, if the magnetic core is in the same position, the current change rate is constant. In other words, the displacement of the solenoid valve has nothing to do with the duty cycle of the applied voltage, but is related to the current change rate.

[0070] In this way, the displacement detection method according to the above embodiment of the present disclosure can detect the displacement of the magnetic core relative to the reference position in a certain time period by detecting the rate of change of the current flowing through the coil in the time period, without setting up an additional sensor. Therefore, the displacement detection method according to the above embodiment of the present disclosure can further simplify the hardware structure of the thermal management system that uses the electromagnetic valve to achieve thermal management, and save costs.

[0071] The present disclosure proposes a displacement detection method, which can minimize or even completely eliminate at least one of the above-mentioned disadvantages 1-1 to 1-5 of the prior art mentioned in the background technology section. Compared with the prior art, the displacement detection method proposed in the present disclosure is characterized in that:

[0072] Taking into account that the displacement change of the solenoid valve causes the self-inductance change of the solenoid valve, which in turn causes the peak-to-peak value change of the solenoid valve current, the displacement information of the solenoid valve can be obtained according to the current change rate;

[0073] Using the displacement detection concept proposed in the present disclosure, no additional sensors are required;

[0074] Displacement detection technology without using sensors, high reliability and long service life;

[0075] The displacement information of the solenoid valve can be obtained from the terminal that is also used to supply power to the solenoid valve;

[0076] A sensorless displacement information decoding method based on power line carrier is proposed.

[0077] By having the above features, the displacement detection method according to various aspects of the present disclosure can have the following beneficial technical effects:

[0078] Can directly measure the opening of the solenoid valve;

[0079] ·Displacement detection can be performed without additional cost;

[0080] No additional space is required to configure and install sensors;

[0081] No need for additional wiring harnesses that increase vehicle functional risk and wiring weight;

[0082] No need to consider the structural strength, reliability and failure mode of the additional sensor, thus reducing the design difficulty;

[0083] It can expand the application range of low-cost thermal management systems driven by solenoid valves;

[0084] The solenoid valve with power line carrier is not only suitable for the application field of thermal management system, but also for the automatic control application field of HVAC system and hydrogen fuel cell engine system;

[0085] · Since there is no outsourcing of EE components, the efficiency of cost reduction is significantly improved.

[0086] Example 2

[0087] According to an embodiment of the present disclosure, a flow detection method is used to detect the flow rate of a fluid flowing in a pipeline controlled by a solenoid valve. Figure 1 The structure of the solenoid valve has been described. Therefore, it will not be repeated in this embodiment. Figure 8 As shown, the flow distribution of the fluid flowing in the pipeline controlled by the solenoid valve is directly related to the displacement of the magnetic core of the solenoid valve. Therefore, the dynamic flow distribution can be estimated by detecting the displacement of the magnetic core of the solenoid valve. Therefore, in the flow detection method according to the embodiment of the present disclosure, the displacement of the movable magnetic core is detected in real time during the operation of the proportional solenoid valve, and the relationship between the displacement of the solenoid valve and the real-time flow is established through CFD analysis. Here, it is assumed that the pipeline controlled by the solenoid valve is the pipeline where port B is located. Therefore, according to the displacement D of the solenoid valve, the flow of the fluid flowing in the pipeline where port B is located can be detected.

[0088] like Fig. 9 As shown, the flow detection method according to an embodiment of the present disclosure mainly includes steps S600 to S800. In step S600, the displacement D of the solenoid valve in the unit time period can be detected by using the displacement detection method described in Example 1. Then, in step S700, the opening S of the pipeline in the unit time period is determined according to the displacement D of the solenoid valve. slot .like Figure 8 As shown, the opening of pipeline B is S slot It must be a function of the magnetic core displacement D of the solenoid valve. Therefore, in a possible implementation, the displacement D of the solenoid valve and the opening S of the pipeline can be pre-established through structural features. slot The relationship between them is shown in formula (3):

[0089] S slot =F(D) (3)

[0090] Therefore, in step S700, the opening degree S of the pipeline in the unit time period can be determined by using formula (3). slot .

[0091] In step S800, according to the opening degree S of the pipeline slot and the velocity v of the fluid flowing to the pipeline in the unit time period, to determine the flow rate Q of the fluid flowing in the pipeline in the unit time period. In a possible implementation, in combination with the Bernoulli principle, the velocity v of the fluid flowing to the pipeline can be calculated using formula (4):

[0092]

[0093] Among them, Figure 8 As shown, P′ represents the pressure on the equivalent cross-sectional area Sarea of ​​the magnetic core of the solenoid valve, P represents the pressure near the equivalent cross-sectional area (for example, at point X), and ρ represents the density of the fluid. Of course, the pressure near the equivalent cross-sectional area is not limited to the pressure at point X. Those skilled in the art can know which position to use as the position near the equivalent cross-sectional area, and can calculate the velocity v of the fluid flowing to the pipeline based on the pressure at the position.

[0094] Combining the above formulas (3) and (4), in a possible implementation, the flow rate Q of the fluid flowing in the pipeline can be calculated using formula (5):

[0095]

[0096] In a possible implementation, the water pump speed WP_Speed ​​can be first obtained through the bus signal of the vehicle, and then the pressure at a certain position X where the water pump speed WP-Speed ​​is different can be obtained through CFD simulation or measurement. That is, the pressure P can be calculated using formula (6):

[0097] P=F(WP_Speed) (6)

[0098] In addition, the fluid force F generated by the fluid flowing in the pipeline Liquid and the electromagnetic force F generated by the solenoid valve due to power on mag The electromagnetic force F mag To calculate the equivalent cross-sectional area S area That is, in a possible implementation, the pressure P' can be calculated using formulas (7) and (8):

[0099] F Liquid =F mag (7)

[0100]

[0101] Among them, one can use, for example, Fig.10 The electromagnetic force F is determined by the solenoid valve characteristics shown in mag . Fig.10 The electromagnetic force F of the solenoid valve obtained by gradually increasing the current applied to the solenoid valve from 0A to 12A and then gradually decreasing from 12A to 0A is shown in FIG. mag The changing curve of the current has a hysteresis characteristic, so that the electromagnetic force when the current gradually increases (the upper curve) is different from the electromagnetic force when the current gradually decreases (the lower curve).

[0102] In this way, the flow detection method according to an embodiment of the present disclosure can detect the flow rate of the fluid flowing in the pipeline controlled by the solenoid valve. Similar to Example 1, the flow detection method according to an embodiment of the present disclosure may also include: sending the detected flow rate Q of the fluid flowing in the pipeline within a unit time period in real time to a control device such as an ECU for performing the thermal management. In this way, the ECU can grasp the actual state of the fluid in the pipeline controlled by the solenoid valve in real time, so that thermal management can be performed more effectively. In addition, the ECU can also display the data in real time on the main screen of the vehicle to facilitate the driver to understand the current state of the vehicle during driving.

[0103] Of course, those skilled in the art can decide how to use the obtained traffic data according to the actual application scenario, and the present disclosure does not provide any further explanation or limitation on this.

[0104] It should also be noted that, although a possible way to implement steps S600 to S800 is exemplified above with a specific calculation formula, the present disclosure is not limited to this. Inspired by the concept of estimating the flow rate of the fluid flowing in the pipeline controlled by the solenoid valve based on the displacement of the solenoid valve, those skilled in the art should be able to use other methods to implement the above steps S600 to S800 according to the basic knowledge they have mastered, given in the present disclosure. In other words, there are many ways to implement steps S600 to S800, and the present disclosure cannot list them all. However, as long as steps S600 to S800 are used to detect the flow rate of the fluid flowing in the pipeline controlled by the solenoid valve, they all fall within the scope of protection of the present disclosure.

[0105] like Fig.11 As shown, a prototype has been produced according to the flow detection method disclosed in the present invention. For example, the current applied to the solenoid valve is Fig.11 If the current is linearly controlled (i.e., the current is linearly increased and linearly decreased in sequence), the fluid flow rate at the inlet end and the fluid flow rate at the outlet end will also change accordingly (see Fig.11 In addition, the pressure change at the inlet end will also change accordingly, while the pressure at the outlet end will not change significantly (see Fig.11 ).

[0106] The general result of this concept shows that the flow rate of each port can be distributed accordingly with the linear increase and decrease of the dynamic current. That is, the control of the flow rate at the inlet end and the distribution of the flow rate at the outlet end can be achieved by changing the current applied to the solenoid valve. After CFD simulation optimization, the inventors of the present disclosure determined that the flow characteristics must be related to the shape of the valve and the valve seat. Therefore, the results verify the repeatability of the flow distribution and the correlation of the flow rate with the displacement of the solenoid valve and the valve type.

[0107] Thus, the flow rate of the solenoid valve at a certain opening can be estimated. On this basis, flow distribution can be further realized. At the same time, due to the proportional characteristics of the solenoid valve, the flow controllability based on flow estimation is an approximate functional relationship with the displacement of the solenoid valve. Therefore, sharp flow deviations can be avoided.

[0108] In this way, due to the existence of real-time flow feedback, flow feedback can be introduced into the closed loop of coolant temperature control, thereby improving the thermal management efficiency and accuracy of the thermal management system. Among them, temperature control includes but is not limited to the application of flow in the thermal management of the whole vehicle or the advanced closed-loop control technology or adaptive control of the flow link involved in thermal management, such as feeding back real-time flow control information and temperature information to the general diagnostic service or OBD II.

[0109] The present disclosure proposes a flow detection method, which can minimize or even completely eliminate at least one of the above-mentioned shortcomings 2-1 to 2-4 of the prior art mentioned in the background technology section. The flow detection method proposed in the present disclosure is characterized by:

[0110] Establish the relationship between the displacement of the solenoid valve and the flow rate of the pipeline controlled by the solenoid valve, and then estimate the flow distribution characteristics in real time;

[0111] The ability to introduce flow feedback allows the original coolant system's hysteresis temperature control to be upgraded to a certain point of predictable temperature control, thereby improving the coolant system's thermal management accuracy;

[0112] Able to provide flow monitoring and flow self-diagnosis functions for OBDII, so as to detect the operating status and diagnose faults of hybrid vehicles and new energy vehicles.

[0113] By having the above features, the flow detection method according to various aspects of the present disclosure can have the following beneficial technical effects:

[0114] The flow rate at a certain opening of the solenoid valve can be estimated in real time, and the acquired flow information can be provided to common applications, such as dynamic flow control for appropriate temperature points or OEM OBD II mandatory requirements;

[0115] Due to the proportional characteristics of the solenoid valve, the flow controllability based on the flow estimation is an approximate functional relationship with the displacement of the solenoid valve, so that sharp flow deviations can be avoided;

[0116] ● Real-time flow information can be transmitted directly through the power line for universal use, thus reducing costs;

[0117] · Flow estimation is the basis of coolant temperature self-calibration. As long as there is a matching point, it can be automatically performed without manual flow and temperature matching, so it has wide applicability.

[0118] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A flow detection method for detecting the flow of a fluid flowing in a pipeline controlled by a solenoid valve used in thermal management, wherein: The solenoid valve includes a coil and a magnetic core, and by applying a voltage with a specific duty cycle to the coil, the magnetic core can be displaced to control the fluid flowing in the pipeline in which the solenoid valve is provided, thereby achieving the thermal management, and is characterized in that it includes: sampling the current flowing through the coil; Calculate the change rate di / dt of the current flowing through the coil in a unit time period between a first moment T0 and a second moment T1 after a unit time Δt has passed since the first moment T0; Calculate the average value U of the voltage applied to the coil in the unit time period ave ; According to the current change rate di / dt and the average value U of the voltage ave , determine the inductance L of the coil in the unit time period; Obtaining a displacement D of the magnetic core relative to a reference position within the unit time period according to the inductance L of the coil, and using the displacement D of the solenoid valve within the unit time period; According to the displacement D of the solenoid valve, the opening S of the pipeline in the unit time period is determined. slot ;as well as According to the opening S of the pipeline slot and the velocity v of the fluid flowing to the pipeline in the unit time period, determine the flow rate Q of the fluid flowing in the pipeline in the unit time period.

2. The flow detection method according to claim 1, characterized in that: Also includes: The displacement D of the solenoid valve and the opening S of the pipeline are established in advance. slot The relationship between them is shown in formula (3): S slot =F(D) (3) Wherein, the opening S of the pipeline in the unit time period is determined by formula (3): slot .

3. The flow detection method according to claim 1 or 2, characterized in that: The method further comprises: using formula (4) to calculate the velocity v of the fluid flowing to the pipeline: Among them, P ′ represents the pressure on the equivalent cross-sectional area of ​​the magnetic core of the solenoid valve, P represents the pressure near the equivalent cross-sectional area, and ρ represents the density of the fluid.

4. The flow detection method according to claim 1 or 2, characterized in that: Also includes: The flow rate Q of the fluid flowing in the pipeline in each unit time period is determined, and the determined flow rate Q of the fluid flowing in the pipeline in each unit time period is sent in real time to the control device for performing the thermal management.

5. The flow detection method according to claim 1, characterized in that: The current flowing through the coil is sampled in real time, and the sampled current is smoothed. The smoothed current is used to calculate the rate of change di / dt of the current in each unit time period, thereby obtaining the displacement D of the solenoid valve in each unit time period.

6. The flow detection method according to claim 5, characterized in that: Also includes: The obtained displacement D of the solenoid valve within each unit time period is sent in real time to a control device for performing the thermal management.

7. The flow detection method according to claim 1, characterized in that: The inductance L of the coil in the unit time period is determined using formula (1): L=(U ave -i0R)(di / dt) -1 (1) Herein, i0 represents the current flowing through the coil at the first moment T0, and R represents the resistance of the coil.

8. The flow detection method according to claim 1, characterized in that: Formula (2) is used to obtain the displacement D of the magnetic core relative to the reference position in the unit time period: Wherein, μ represents the relative magnetic permeability of the magnetic core, N represents the number of turns of the coil, and S represents the effective cross-sectional area of ​​the solenoid valve.

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