A control method for valve soft landing

Abstract

The present invention discloses a control method for soft landing of a valve, and relates to the field of valve control technology. The control method comprises: obtaining the stroke of the valve core of the valve, and determining the range of the soft landing intervals of the open side and the closed side of the stroke respectively; obtaining the target position of the valve core, and judging whether the target position is within the soft landing interval; if so, obtaining the state of the valve core, and judging whether the state of the valve core meets the conditions for opening the soft landing control; if so, performing soft landing control on the movement of the valve core. The control method for soft landing of the valve can perform soft landing control on the valve core, thereby avoiding the impact of the valve core on the valve body and extending the service life of the valve.

Description

Technical Field

[0001] The invention relates to the technical field of valve control, and in particular to a control method for soft landing of a valve. Background Art

[0002] The flow rate of the coolant in a car engine is usually controlled by a thermostatic valve. The advantages are fast response speed, improved temperature control accuracy, improved engine cooling effect, and help to increase engine output power.

[0003] However, the opening of the thermostatic valve corresponds to the stroke of the valve core. When the valve core moves to the limit position, the thermostatic valve is in a fully open or fully closed state. It is understandable that if the opening of the thermostatic valve needs to be close to fully open or fully closed, or even fully open or fully closed, the valve core distance is at both ends of the entire stroke. In terms of structure, the valve core is prone to a certain impact on the valve body, accelerating the aging of the valve body and damaging the valve body over time.

[0004] In view of the above problems, it is necessary to develop a control method for valve soft landing to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a control method for soft landing of a valve, which can perform soft landing control on a valve core, thereby avoiding the impact of the valve core on the valve body and extending the service life of the valve.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A control method for soft landing of a valve, comprising:

[0008] Obtaining the stroke of the valve core of the valve, and determining the range of the soft landing interval on the opening side and the closing side of the stroke respectively;

[0009] Acquiring a target position of the valve core, and determining whether the target position is within the soft landing interval;

[0010] If yes, obtaining the state of the valve core, and determining whether the state of the valve core satisfies the condition for starting the soft landing control;

[0011] If the conditions are met, the movement of the valve core is subjected to soft landing control.

[0012] Preferably, the soft landing intervals on the open side and the closed side are of equal size.

[0013] Preferably, the state of the valve core includes the movement direction of the valve core, and the conditions for starting the soft landing control include:

[0014] The movement direction of the valve core is toward the soft landing interval where the target position is located.

[0015] Preferably, the state of the valve core also includes the current position of the valve core, a start interval is provided at the front end of each soft landing interval, a threshold point is provided at one end of the start interval close to the corresponding soft landing interval, and the condition for starting the soft landing control also includes:

[0016] The current position is within the start interval.

[0017] Preferably, the soft landing control includes:

[0018] Trajectory planning;

[0019] Control the movement speed of the valve core.

[0020] Preferably, the trajectory planning includes:

[0021] The valve core is controlled to move one step at a time, and each time the valve core moves one step, the movement speed of the valve core is controlled once until the valve core moves to the target position.

[0022] Preferably, the step lengths of the valve core moving toward the opening side and the closing side are equal.

[0023] Preferably, controlling the movement speed of the valve core includes: as the distance between the valve core and the target position decreases, the movement speed of the valve core gradually decreases.

[0024] Preferably, the movement speed of the valve core is controlled by changing a PWM signal output by a controller.

[0025] Preferably, the PWM signal has a limit value. If the PWM signal output by the controller is greater than the limit value, the size of the output PWM signal is controlled to be the limit value.

[0026] Beneficial effects of the present invention:

[0027] The present invention provides a control method for valve soft landing. In the control method, the stroke of the valve core needs to be obtained first, and the range of the soft landing interval on the opening side and the closing side is determined according to the total stroke. If the target position to which the valve core needs to be moved is within the range of the soft landing interval, it means that the valve core is likely to impact the valve body. If the state of the valve core at this time meets the conditions for opening the soft landing control, the valve core is subjected to soft landing control.

[0028] The valve soft landing control method can perform soft landing control on the valve core, thereby preventing the valve core from impacting the valve body and extending the service life of the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1is a flow chart of a control method for valve soft landing provided by the present invention;

[0030] Figure 2 It is a structural schematic diagram of the valve stroke provided by the present invention;

[0031] Figure 3 It is the movement trajectory of the valve core when the closing side is planned according to the present invention.

[0032] In the figure:

[0033] 1. Open side; 2. Close side; 3. Soft landing interval; 4. Threshold point; 5. Start interval. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0036] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0039] The flow rate of the coolant in a car engine is usually controlled by a thermostatic valve. The advantages are fast response speed, improved temperature control accuracy, improved engine cooling effect, and help to increase engine output power.

[0040] However, the opening of the thermostatic valve corresponds to the stroke of the valve core. When the valve core moves to the limit position, the thermostatic valve is in a fully open or fully closed state. It is understandable that if the opening of the thermostatic valve needs to be close to fully open or fully closed, or even fully open or fully closed, the valve core distance is at both ends of the entire stroke. In terms of structure, the valve core is prone to a certain impact on the valve body, accelerating the aging of the valve body and damaging the valve body over time.

[0041] To solve the above problems, this embodiment provides a control method for valve soft landing. Figure 1 As shown, the control method includes:

[0042] Obtaining the stroke of the valve core of the valve, and determining the range of the soft landing interval 3 on the opening side 1 and the closing side 2 of the stroke respectively;

[0043] Obtaining the target position of the valve core, and determining whether the target position is within the soft landing interval 3;

[0044] If yes, obtain the state of the valve core and determine whether the state of the valve core satisfies the condition for starting the soft landing control;

[0045] If it is satisfied, the movement of the valve core is controlled to softly land.

[0046] The stroke of the valve core indicates the amount of movement of the valve core when the valve is fully closed to fully open. The two ends of the stroke correspond to the positions of the valve core when the valve is fully open and fully closed, respectively, corresponding to the open side 1 and the closed side 2. When the valve needs to be opened or closed, or is close to opening or closing, the valve core is prone to collide with the valve body, so it is necessary to determine the range of the soft landing interval 3 at both ends of the stroke.

[0047] If the target position of the valve core is within the soft landing interval 3, it means that the valve core may hit the valve body. However, since both the opening side 1 and the closing side 2 have soft landing intervals 3, in order to improve the control accuracy, it is also necessary to determine whether the state of the valve core at this time meets the conditions for opening the soft landing control. If so, the valve core is subjected to soft landing control to prevent the valve core from impacting the valve body.

[0048] The control method for soft landing of the valve can control the soft landing of the valve core, thereby preventing the valve core from impacting the valve body and extending the service life of the valve. The soft landing control refers to decelerating the valve core until it stops at the target position to ensure that the valve core does not impact the valve body.

[0049] Specifically, the thermostatic valve is usually a spherical valve with a position feedback sensor, and the stroke of its valve core is the angle of the valve core when the spherical valve is fully opened to fully closed. Of course, the thermostatic valve can also be a linear valve, and the stroke of its valve core is the distance the valve core moves when the linear valve is fully opened to fully closed.

[0050] In this embodiment, the thermostatic valve is described by taking a spherical valve as an example.

[0051] Preferably, the range of the soft landing interval 3 on the open side 1 and the closed side 2 is equal. The rotation of the valve core toward the open side 1 and the rotation toward the closed side 2 is a symmetrical process. Setting the range of the soft landing interval 3 on the open side 1 and the closed side 2 to be equal can simplify the control logic and improve efficiency.

[0052] Specifically, Figure 2 As shown in the figure, the stroke of the valve core of a general ball valve is 0°~105° (horizontal axis in the figure). If the valve core is defined as the opening side 1 when it is at 0° and the valve core is defined as the closing side 2 when it is at 105°, then the soft landing interval 3 of the opening side 1 ranges from 0°~x°, and the soft landing interval 3 of the closing side 2 ranges from (105-x)°~105°. In practical applications, x can be selected as 5° or other values. The value of x needs to consider the range of soft landing control actually required.

[0053] Preferably, the state of the valve core includes the movement direction of the valve core, and the conditions for starting the soft landing control include:

[0054] The movement direction of the valve core is toward the soft landing interval 3 where the target position is located.

[0055] When the target position of the valve core is in the soft landing interval 3, it is necessary to determine whether the valve core is moving towards the soft landing interval 3 at this time. If not, soft landing control is not required; if so, it means that the valve core may cause an impact on the valve body, and the soft landing control needs to be turned on.

[0056] Furthermore, the state of the valve core also includes the current position of the valve core. A start interval 5 is provided at the front end of each soft landing interval 3. A threshold point 4 is provided at one end of the start interval 5 close to the corresponding soft landing interval 3. The conditions for starting the soft landing control also include:

[0057] The current position is within the starting interval 5.

[0058] It is understandable that after determining that the valve core needs to be soft-landed, it is necessary to accurately determine the time to start the soft-landing control. If the time is too early, the valve core will slow down too early, resulting in a decrease in valve regulation efficiency. If the time is too late, it is easy to cause the valve core to slow down in time and still cause impact on the valve body. Therefore, it is necessary to set the starting interval 5 at the front end of the soft-landing interval 3. When the valve core enters the starting interval 5, that is, the current position of the valve core is close to the soft-landing interval 3, the valve core starts to be soft-landed.

[0059] Specifically, the angle difference between the threshold point 4 and the starting point of the soft landing interval 3 is in the range of 3° to 10°, and its specific value can be determined according to actual needs and the range of the soft landing interval 3. Figure 2 As shown, in this embodiment, the range of the soft landing interval 3 is 5°, and the threshold point 4 can be a point corresponding to 8° and 97° in the stroke of the valve core, and the range of the corresponding starting interval 5 can be obtained by calibration.

[0060] Preferably, the soft landing control includes trajectory planning and controlling the movement speed of the valve core. When the valve core is subjected to soft landing control, it is necessary to plan the next stroke of the valve core and control the speed according to the angle of rotation of the valve core.

[0061] like Figure 3 As shown in the figure, trajectory planning includes controlling the valve core to move one step at a time. Each time the valve core moves one step, the movement speed of the valve core is controlled once until the valve core moves to the target position. The angle corresponding to a step can be calibrated. The trajectory planning can divide the process of the valve core moving from the current position to the target position into multiple sections, and control the speed of the valve core once every time the valve core passes a certain angle, so that the movement speed of the valve core changes smoothly.

[0062] If the valve core moves past the target position after one step, the valve core needs to be controlled to move in the opposite direction until the valve core stops at the target position. Figure 3 Taking the example of planning three steps to move to the target position, in actual control, the size of a step is much smaller than Figure 3 The step size represented in .

[0063] It can be understood that the step lengths of the valve core moving toward the opening side 1 and the closing side 2 are equal, thereby further simplifying the control logic and improving the efficiency.

[0064] Specifically, when the soft landing control is started, the valve core is first controlled to move toward the threshold point 4 during the movement of the valve core toward the soft landing interval 3. When the valve core moves to the threshold point 4 or crosses the threshold point 4, trajectory planning is started and the speed of the valve core is controlled accordingly. It can be understood that during the movement of the valve core, even if it has not reached the threshold point 4, the controller will control the speed of the valve core, and the movement process of the valve core is divided into two sections with the threshold point 4 as the boundary and controlled separately, which can make the control of the valve core more refined.

[0065] Specifically, controlling the movement speed of the valve core includes: as the distance between the valve core and the target position decreases, the movement speed of the valve core gradually decreases. When the valve core approaches the target position, the valve core can be decelerated smoothly, further reducing the impact on the valve body.

[0066] Preferably, the movement speed of the valve core is controlled by changing the PWM signal output by the controller. The running speed of the valve body depends on the size of the PWM signal output by the engine controller. When the soft landing control is triggered, the size of the output PWM signal must be limited so that the running speed of the valve body cannot be too fast. The range of the PWM signal is 0-100%. The size of PWM each time is obtained by the engine controller using a certain calculation based on the difference between the actual position of the valve body and the target position.

[0067] Preferably, the PWM signal has a limit value. If the PWM signal output by the controller is greater than the limit value, the size of the output PWM signal is controlled to be the limit value. The PWM signal calculated by the engine controller may be too large, which will cause the movement speed to be too fast and fail to achieve the effect of smooth deceleration. Therefore, the output PWM signal must be limited. When the PWM value is less than the limit value, it is output normally. When the PWM value is greater than the limit value, the limit value is used as the output value of the PWM signal.

[0068] Among them, the limit value W max =V*f,W max is the limit value of the output PWM signal, V is the battery voltage connected to the engine controller, and f is the coefficient obtained through calibration. W is the actual PWM signal output by the engine controller, W = min (W max , W t )%, among which W t The theoretical PWM signal corresponding to each step is calculated by the engine controller over time.

[0069] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there will be changes in the specific implementation methods and application scopes. The content of this specification should not be understood as limiting the present invention.

Claims

1. A valve soft landing control method, characterized in that: include: Obtaining the stroke of the valve core of the valve, and determining the range of the soft landing interval (3) on the opening side (1) and the closing side (2) of the stroke respectively; Obtaining a target position of the valve core, and determining whether the target position is within the soft landing interval (3); If yes, obtaining the state of the valve core, and determining whether the state of the valve core satisfies the condition for starting the soft landing control; If the conditions are met, the movement of the valve core is subjected to soft landing control; The state of the valve core includes the movement direction of the valve core, and the conditions for starting the soft landing control include: The movement direction of the valve core is toward the soft landing interval (3) where the target position is located; The state of the valve core also includes the current position of the valve core. A starting interval (5) is provided at the front end of each soft landing interval (3). A threshold point (4) is provided at one end of the starting interval (5) close to the corresponding soft landing interval (3). The conditions for starting the soft landing control also include: The current position is within the starting interval (5); The soft landing control includes: Firstly, the valve core is controlled to move toward the threshold point (4), and when the valve core moves to the threshold point (4) or crosses the threshold point (4), trajectory planning is started; Controlling the movement speed of the valve core; The trajectory planning includes: Controlling the valve core to move one step at a time, and controlling the movement speed of the valve core once each time the valve core moves one step, until the valve core moves to the target position; During the movement of the valve core, even if the valve core has not yet reached the threshold point (4), the controller will control the speed of the valve core.

2. The valve soft landing control method according to claim 1, characterized in that: The soft landing intervals (3) on the open side (1) and the closed side (2) are equal in size.

3. The valve soft landing control method according to claim 1, characterized in that: The step lengths of the valve core moving toward the opening side (1) and the closing side (2) are equal.

4. The valve soft landing control method according to claim 1, characterized in that: Controlling the movement speed of the valve core includes: as the distance between the valve core and the target position decreases, the movement speed of the valve core gradually decreases.

5. The valve soft landing control method according to claim 1, characterized in that: The movement speed of the valve core is controlled by changing the PWM signal output by the controller.

6. The valve soft landing control method according to claim 5, characterized in that: The PWM signal has a limit value. If the PWM signal output by the controller is greater than the limit value, the magnitude of the PWM signal output is controlled to be the limit value.

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