Variable displacement water pump for engine and water pump displacement control method

Abstract

The invention discloses a variable-displacement water pump for an engine and a water pump displacement control method, and relates to the technical field of water pumps, the variable-displacement water pump comprises a pump body, an impeller disc, an elastic part and a driving part, a pump shaft is rotationally connected to the center of the pump body, an impeller cover is fixedly connected to one end of the pump shaft, and a plurality of blades are arranged on the face, facing the pump body, of the impeller cover in the circumferential direction; the impeller disc sleeves the pump shaft, the impeller disc and the impeller cover are coaxially and oppositely arranged, the impeller disc can slide in the axial direction of the pump shaft, the impeller disc is provided with holes allowing the blades to penetrate through, the hole walls of the holes and the peripheral surfaces of the blades define liquid drainage intervals, the pump shaft is sleeved with the elastic piece, one end of the elastic piece abuts against the impeller disc, and the other end of the elastic piece abuts against the impeller disc. The driving part is arranged on the face, away from the impeller cover, of the impeller disc, the driving end of the driving part abuts against the impeller disc, and the acting force of the elastic part is opposite to that of the driving part. The size of the liquid drainage interval is adjusted through cooperation of the driving piece and the elastic piece, and variable displacement and oil consumption reduction are achieved.

Description

Technical Field

[0001] This invention relates to the field of engine water pump technology, specifically to a variable displacement water pump for engines and a method for controlling the pump displacement. Background Technology

[0002] For traditional automotive engines, continuously improving thermal efficiency is a crucial direction for reducing carbon emissions. The mechanical water pump is a vital component of the engine, providing sufficient coolant to maintain its operation within an appropriate temperature range. Current engine water pumps generally use traditional belt drives, connecting the pump pulley to the crankshaft via a belt. Due to the fixed transmission ratio, the pump speed is directly proportional to the engine speed. The pump speed determines the flow rate, head, and energy consumption. At low engine speeds, the pump flow rate is low and energy consumption is low; at high engine speeds, the pump flow rate is high and energy consumption is high. To ensure the vehicle's cooling needs under low-speed, high-load conditions, mechanical pumps are typically designed with performance exceeding a certain capacity at low speeds. However, at high speeds, this leads to excessive pump capacity, causing unnecessary heat loss from the engine and excessive energy consumption, resulting in increased fuel consumption. Summary of the Invention

[0003] This application provides a variable displacement water pump for an engine and a water pump displacement control method, which can solve the technical problem of uncontrollable water pump displacement in the prior art.

[0004] In a first aspect, embodiments of this application provide a variable displacement water pump for an engine, the variable displacement water pump for an engine comprising: The pump body has a pump shaft rotatably connected to its center, and an impeller cover is fixedly connected to one end of the pump shaft. The impeller cover has multiple blades arranged circumferentially on the side facing the pump body. An impeller disk is sleeved on the pump shaft and is coaxially and directly opposite the impeller cover. The impeller disk is slidably arranged along the axial direction of the pump shaft. The impeller disk has holes for the blades to pass through. The hole wall and the outer peripheral surface of the blades form a drainage gap. An elastic element is sleeved on the pump shaft, one end of the elastic element abuts against the impeller disk, and the other end of the elastic element abuts against the inner cavity of the pump body; A driving member is disposed on the side of the impeller disk away from the impeller cover, and the driving end of the driving member abuts against the impeller disk. The elastic member acts in the opposite direction to the driving member.

[0005] In conjunction with the first aspect, in one embodiment, the cross-sectional dimension of the hole is larger than the cross-sectional dimension of the blade, and the number and location of the hole correspond to the number and location of the blade.

[0006] In conjunction with the first aspect, in one embodiment, the driving component is a solenoid valve, the valve body of the solenoid valve is fixedly connected to the inner wall of the pump body, the driving end of the solenoid valve is a valve core, and the valve core extends along the axial direction of the pump shaft to abut against the center of the impeller disk.

[0007] In conjunction with the first aspect, in one embodiment, the end of the valve core is provided with a hemispherical protrusion, which abuts against the center of the impeller disk.

[0008] In conjunction with the first aspect, in one embodiment, a wear-resistant washer is sandwiched between the valve core and the impeller disk.

[0009] In conjunction with the first aspect, in one embodiment, the outer diameter of the wear-resistant washer is larger than the diameter of the valve core end.

[0010] In conjunction with the first aspect, in one embodiment, the variable displacement water pump for the engine further includes: A controller electrically connected to the drive unit, the controller being configured to control the on / off state of the drive unit according to the engine speed.

[0011] In conjunction with the first aspect, in one embodiment, the impeller cover is disc-shaped, the blades extend radially along the impeller cover, and a plurality of the blades are evenly spaced apart in the circumferential direction of the impeller cover.

[0012] Secondly, embodiments of this application provide a water pump displacement control method for controlling the displacement of a variable displacement water pump for an engine as described in any of the above embodiments. The water pump displacement control method includes: Obtain the current engine speed and compare it with a preset speed threshold. Based on the comparison results, the on / off state of the drive component is controlled to adjust the axial spacing of the drainage interval between the impeller disk and the impeller cover.

[0013] In conjunction with the second aspect, in one implementation, it further includes: If the current speed of the engine is less than or equal to the preset speed threshold, the control drive is in a power-off state, the axial distance between the impeller disk and the impeller cover is the first distance, and the water pump operates at the first displacement. If the current speed of the engine is greater than the preset speed threshold, the control drive is in the energized state, the axial distance between the impeller disk and the impeller cover is the second distance, and the water pump operates at the second displacement. Wherein, the first spacing is greater than the second spacing, and the first displacement is greater than the second displacement.

[0014] The beneficial effects of the technical solutions provided in this application include: This embodiment controls the axial position of the impeller disk through the cooperation of the driving component and the elastic component. The size of the discharge interval can be adjusted in real time according to the actual operating conditions of the engine. Under low-demand conditions, the water pump can reduce the discharge interval to decrease flow rate and driving power, thereby directly reducing engine power consumption and helping to reduce engine fuel consumption. Under high-demand conditions, the discharge interval can be increased to ensure sufficient cooling capacity. This embodiment avoids the limitation of clutch-driven water pumps, which can only achieve on / off control and cannot continuously adjust flow rate. Furthermore, variable displacement is achieved solely through the cooperation of the impeller disk, elastic component, and driving component. The structural complexity is lower than that of electronic water pumps, resulting in lower costs, and no changes to the engine's front-end wheel system arrangement are required. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a variable displacement water pump for an engine provided in an embodiment of this application; Figure 2 A cross-sectional view of a variable displacement water pump for an engine provided in an embodiment of this application; Figure 3 An exploded schematic diagram of a variable displacement water pump for an engine provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the impeller cover and impeller disk in an embodiment of this application.

[0017] In the diagram: 1. Pump body; 2. Impeller cover; 21. Blade; 3. Impeller disk; 31. Hole; 4. Pump shaft; 5. Elastic component; 6. Drive component; 7. Drainage interval. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral 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 a connection within two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0019] This application provides a variable displacement water pump for an engine and a water pump displacement control method, which can solve the technical problem of uncontrollable water pump displacement in the prior art.

[0020] In a first aspect, embodiments of this application provide a variable displacement water pump for an engine.

[0021] Figure 1 This is a schematic diagram of the structure of a variable displacement water pump for an engine provided in an embodiment of this application. See also... Figure 1 The variable displacement water pump for the engine includes: a pump body 1, a pump shaft 4 rotatably connected to the center of the pump body 1, an impeller cover 2 fixedly connected to one end of the pump shaft 4, and multiple blades 21 arranged circumferentially on the side of the impeller cover 2 facing the pump body 1; an impeller disk 3, which is sleeved on the pump shaft 4 and coaxially opposite to the impeller cover 2, and is slidable along the axial direction of the pump shaft 4, with holes 31 for the blades 21 to pass through, the hole wall of the hole 31 and the outer circumferential surface of the blades 21 forming a drainage interval 7; an elastic element 5, which is sleeved on the pump shaft 4, with one end of the elastic element 5 abutting against the impeller disk 3 and the other end of the elastic element 5 abutting against the inner cavity of the pump body 1; and a drive element 6, which is located on the side of the impeller disk 3 away from the impeller cover 2, and the drive end of the drive element 6 abutting against the impeller disk 3, with the elastic element 5 and the drive element 6 acting in opposite directions.

[0022] Figure 2A cross-sectional view of a variable displacement water pump for an engine provided in an embodiment of this application. See also... Figure 2 Specifically, the pump body 1 is the fixed housing of the water pump, and the inner cavity of the pump body 1 forms a coolant flow channel. The pump shaft 4 is a rotatable power input shaft, supported on the pump body 1 by bearings. The impeller cover 2 is fixedly connected to the end of the pump shaft 4. As the pump shaft 4 rotates synchronously, the impeller cover 2 has multiple blades 21 arranged circumferentially on the side facing the pump body 1. The blades 21 can generate centrifugal motion of the coolant. The blades 21 can be radial straight blades or backward-curved blades. The blades 21 are integrally formed or welded to the impeller cover 2. A through hole is opened at the center of the impeller disk 3 for fitting onto the pump shaft 4. The impeller disk 3 and the pump shaft 4 form an axially sliding fit. The impeller disk 3 has holes 31 in the same number and corresponding positions as the blades 21. The outline dimension of the holes 31 is larger than the cross-section of the blades 21.

[0023] The impeller consists of an impeller cover 2 and an impeller disk 3. Each blade 21 on the impeller cover 2 passes through a corresponding hole 31 on the impeller disk 3, thus ensuring that when the impeller cover 2 rotates, the impeller disk 3 can be driven to rotate synchronously through the side of the blades 21. At the same time, the impeller disk 3 can slide freely along the pump shaft 4 axis within the axial length range of the blades 21. The drain interval 7 is a coolant discharge channel formed by the end face of the blades 21 of the impeller cover 2, the disk surface of the impeller disk 3, and the side of the blades 21. It is located on the outer periphery of the impeller, and the axial spacing of the drain interval 7 changes as the impeller disk 3 slides axially. Driven by the blades 21, the coolant is thrown towards the pump body 1 outlet through the drain interval 7.

[0024] The elastic element 5 can specifically be a helical compression spring. There is a gap between the impeller cover 2 and the impeller disk 3 near the pump shaft 4. The elastic element 5 is sleeved on the pump shaft 4 and axially confined within this gap. The elastic element 5 constantly applies an axial force pointing inwards towards the pump body 1 to the impeller disk 3. The drive element 6 can specifically be a solenoid valve. The drive element 6 can output an axial thrust opposite to the direction of the force exerted by the elastic element 5, used to push the impeller disk 3 towards the impeller cover 2.

[0025] When the engine drives the pump shaft 4 to rotate via a belt, the impeller cover 2 rotates synchronously, and the blades 21 pass through the holes 31 of the impeller disk 3, causing the impeller disk 3 to rotate synchronously. The coolant gains kinetic energy under the action of the rotating blades 21, and after radial acceleration through the flow channels between the blades 21, it is discharged from the outer peripheral drain interval 7 to the pump body 1, and then supplied to the engine cooling circuit through the outlet. In this embodiment, under low-speed conditions, the solenoid valve is de-energized, and the restoring force of the elastic element 5 moves the impeller disk 3 away from the impeller cover 2, increasing the drain interval 7 and increasing the coolant flow rate to meet cooling requirements. Under high-speed conditions, the solenoid valve is energized, and the driving element 6 overcomes the elastic force of the elastic element 5, causing the impeller disk 3 to move closer to the impeller cover 2, decreasing the drain interval 7 and correspondingly reducing the flow rate to avoid overcooling.

[0026] In this embodiment, the effective power consumed by the water pump during operation is used to enhance the potential energy of the coolant, and the specific calculation formula is as follows:

[0027] in, Indicates the effective power of the water pump. Indicates the density of the coolant. Represents gravitational acceleration. Indicates the water pump flow rate. This indicates the water pump head. Therefore, given a fixed coolant density and water pump head, the effective power of the water pump is directly proportional to the water pump flow rate. Thus, reducing unnecessary flow output is a direct way to save engine energy.

[0028] Given a fixed number and shape of blades 21, the flow rate of the water pump is determined by the pump speed and the discharge interval 7. The relationship between the coolant velocity in the discharge interval 7 and the impeller speed and the width of the impeller outlet flow channel is as follows:

[0029] in, This indicates the tangential velocity of the coolant at the impeller outlet. Indicates the impeller speed. This indicates the impeller diameter.

[0030] The specific calculation method for the flow area of ​​the drainage interval 7 in this embodiment is as follows:

[0031] in, This indicates the flow area of ​​drainage interval 7. This indicates the axial spacing of the drainage interval 7. This indicates the width of the impeller outlet flow channel.

[0032] Combining the above formulas, the pump flow rate can be expressed as:

[0033] Therefore, the effective power of the water pump can be further expressed as a direct relationship with the axial distance of the discharge interval 7, specifically:

[0034] Therefore, given a fixed impeller speed, pump head, and impeller outlet flow channel width, the effective power of the pump is directly proportional to the axial spacing of the discharge interval 7. Thus, in this embodiment, the power of the pump can be adjusted by changing the axial spacing of the discharge interval 7, thereby reducing engine fuel consumption.

[0035] In this embodiment, the cross-sectional dimension of the hole 31 is larger than the cross-sectional dimension of the blade 21, and the number and position of the holes 31 correspond to the number and position of the blades 21.

[0036] Figure 3 An exploded view of a variable displacement water pump for an engine provided in an embodiment of this application. See also... Figure 3 Specifically, the number of holes 31 distributed circumferentially on the impeller disk 3 and the angular positions between each hole 31 are the same as the number of blades 21 on the impeller cover 2 and the angular positions between each blade 21. The holes 31 on the impeller disk 3 are through holes, and the outline of the holes 31 is larger than the outline of the blades 21 in both the radial and tangential directions, forming a radial gap. This provides a certain space for the impeller disk 3 to slide relative to the blades 21 along the axis of the pump shaft 4 without mechanical interference.

[0037] In this embodiment, the driving component 6 is a solenoid valve. The valve body of the solenoid valve is fixedly connected to the inner wall of the pump body 1. The driving end of the solenoid valve is the valve core, which extends along the axial direction of the pump shaft 4 to abut against the center of the impeller disk 3.

[0038] Specifically, the valve body of the solenoid valve, as the stationary part of the solenoid valve, is directly installed and fixed on the inner wall of the pump body 1. The valve core of the solenoid valve, as the motion output part of the solenoid valve, can move linearly along its axis within the valve body. The installation direction of the valve core is parallel to the axial direction of the pump shaft 4. The drive end of the valve core extends out from the valve body and abuts against the outer surface of the central region of the impeller disk 3.

[0039] In this embodiment, the end of the valve core is provided with a hemispherical protrusion, which abuts against the center of the impeller disk 3.

[0040] Specifically, the hemispherical protrusion is the direct point of application for the axial thrust exerted by the valve core on the impeller disk 3. When the solenoid valve is energized and the valve core extends, the thrust is transmitted to the impeller disk 3 through the apex or spherical area of ​​the hemispherical protrusion, driving the impeller disk 3 to slide axially. By setting the hemispherical protrusion, local stress concentration can be reduced, decreasing the possibility of plastic deformation or wear on the contact surface between the valve core and the impeller disk 3, thereby improving the life and stability of the variable displacement water pump for the engine.

[0041] In this embodiment, a wear-resistant washer is sandwiched between the valve core and the impeller disk 3.

[0042] Specifically, during long-term dynamic force transmission, wear between the contact surfaces of the valve core and the impeller disk 3 is inevitable. In this embodiment, by sandwiching a gasket made of a specialized wear-resistant material between the valve core and the impeller disk 3, the wear can be primarily concentrated on the wear-resistant gasket, further improving the lifespan of the variable displacement water pump for the engine. Furthermore, the wear-resistant gasket can be made of materials such as silicon carbide ceramic. In some other embodiments of this application, other materials can also be used to make the wear-resistant gasket, as long as they meet the requirements of high hardness and wear resistance; this is not limited here.

[0043] In this embodiment, the outer diameter of the wear-resistant washer is larger than the diameter of the valve core end.

[0044] Specifically, the wear-resistant washer can cover the projected area of ​​the valve core's drive end in the radial direction, thereby ensuring that the force application point of the valve core's drive end always falls on the working surface of the wear-resistant washer, thus ensuring the continuity and reliability of the thrust transmission path.

[0045] In this embodiment of the application, the variable displacement water pump for the engine further includes a controller, which is electrically connected to the drive unit 6 and is configured to control the on / off state of the drive unit 6 according to the engine speed.

[0046] Specifically, the driving component 6 is a solenoid valve. When the controller applies a control current to the coil of the solenoid valve, the electromagnetic force generated by the coil drives the valve core to produce axial displacement and outputs thrust. The magnitude and direction of the current determine the magnitude of the electromagnetic force and the direction of movement of the valve core.

[0047] When the controller determines that the pump displacement needs to be reduced based on the operating conditions, it controls the solenoid valve to supply the corresponding current, causing the valve core to extend towards the impeller disk 3. The thrust output by the valve core directly acts on the impeller disk 3, pushing it to slide along the pump shaft 4 towards the impeller cover 2, thereby reducing the axial distance between the impeller disk 3 and the impeller cover 2, i.e., reducing the axial height of the discharge interval 7. When the controller determines that the pump displacement needs to be increased based on the operating conditions, it controls the solenoid valve to reduce or cut off the corresponding current, weakening or eliminating the electromagnetic force. At this time, the compressed elastic element 5 releases its stored elastic force, pushing the impeller disk 3 to reset in the opposite direction, while simultaneously forcing the valve core to retract, thereby increasing the axial distance between the impeller disk 3 and the impeller cover 2, i.e., increasing the axial height of the discharge interval 7. Therefore, the adjustment of the pump displacement is achieved through the opposing forces of the solenoid valve's thrust and the elastic element 5's reset force, thus adjusting the position of the impeller disk 3.

[0048] In this embodiment, the impeller cover 2 is disc-shaped, and the blades 21 extend along the radial direction of the impeller cover 2. The multiple blades 21 are evenly spaced in the circumferential direction of the impeller cover 2.

[0049] Figure 4This is a schematic diagram illustrating the structure of the impeller cover 2 and impeller disk 3 in conjunction with each other, as provided in an embodiment of this application. See also... Figure 4 Specifically, the radially extending blades 21 and the disc-shaped impeller cover 2 together form a radial flow channel from the shaft center to the outer edge. When the impeller rotates, the coolant entering the flow channel moves in a circular motion with the impeller under the action of the blades 21, and at the same time flows radially outward guided by the curved surface of the blades 21. This provides a uniform flow channel for the coolant and ensures the basic performance of the water pump.

[0050] Secondly, embodiments of this application provide a water pump displacement control method for controlling the displacement of a variable displacement water pump for an engine in any of the above embodiments. The water pump displacement control method includes: Obtain the current engine speed and compare it with a preset speed threshold. Based on the comparison results, the on / off state of the drive component 6 is controlled to adjust the axial spacing of the drainage interval 7 between the impeller disk 3 and the impeller cover 2.

[0051] Specifically: If the current speed of the engine is less than or equal to the preset speed threshold, the control drive 6 is in a de-energized state, the axial distance of the drain interval 7 between the impeller disk 3 and the impeller cover 2 is the first distance, and the water pump operates at the first displacement. If the current speed of the engine is greater than the preset speed threshold, the control drive 6 is energized, the axial distance of the drain interval 7 between the impeller disk 3 and the impeller cover 2 is the second distance, and the water pump operates at the second displacement. Among them, the first spacing is greater than the second spacing, and the first displacement is greater than the second displacement.

[0052] In this embodiment, the preset speed threshold can be the critical speed point at which the engine cooling demand changes significantly. When the current engine speed is less than or equal to the preset speed threshold, it is determined that the engine may be under high load and low speed conditions, requiring strong cooling capacity to prevent overheating or rapid circulation establishment. Therefore, the water pump is set to operate at a large displacement to provide sufficient coolant flow to ensure engine thermal safety or promote warm-up. When the current engine speed is greater than the preset speed threshold, it is determined that the engine has entered the medium-to-high speed range. If the heat load is not high at this time, there may be a risk of excessive cooling capacity. Therefore, the water pump is set to operate at a small displacement to suppress excessive flow output, thereby avoiding unnecessary water pump power consumption.

[0053] When the drive unit 6 is de-energized, the valve core has no electromagnetic thrust output. The restoring force of the elastic element 5 inside the water pump pushes the impeller disk 3 to a preset position. At this time, a large first gap is formed between the impeller disk 3 and the impeller cover 2, and the corresponding flow channel cross-section is large. The water pump is in the first displacement working state. When the drive unit 6 is energized, the valve core generates electromagnetic thrust, which overcomes the restoring force of the elastic element 5 and pushes the impeller disk 3 axially to another preset position, forming a smaller second gap. This reduces the flow cross-section of the discharge interval 7, and the water pump is in the second displacement working state.

[0054] This embodiment controls the axial position of the impeller disk 3 through the cooperation of the drive component 6 and the elastic component 5. The size of the discharge interval 7 can be adjusted in real time according to the actual operating conditions of the engine. Under low-demand conditions, the water pump can reduce the discharge interval 7 to decrease flow rate and drive power, thereby directly reducing engine power consumption and helping to reduce engine fuel consumption. Under high-demand conditions, the discharge interval 7 can be increased to ensure sufficient cooling capacity. This embodiment avoids the limitations of clutch-type water pumps, which can only achieve on / off control and cannot continuously adjust flow rate. Furthermore, variable displacement is achieved solely through the cooperation of the impeller disk 3, elastic component 5, and drive component 6. This reduces structural complexity compared to electronic water pumps, lowers costs, and eliminates the need to change the engine's front-end wheel system arrangement.

[0055] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0056] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A variable displacement water pump for an engine, characterized in that, The engine variable displacement water pump comprises: a pump body (1) having a pump shaft (4) rotatably connected at the center of the pump body (1), one end of the pump shaft (4) being fixedly connected with an impeller cover (2), a plurality of blades (21) being circumferentially arranged on one side of the impeller cover (2) facing the pump body (1); an impeller disc (3) being coaxially and oppositely arranged with the impeller cover (2) and sleeved on the pump shaft (4), the impeller disc (3) being slidably arranged along the axial direction of the pump shaft (4), the impeller disc (3) being provided with a plurality of holes (31) for the blades (21) to pass through, the hole walls of the holes (31) and the outer circumferential surfaces of the blades (21) surrounding the holes (31) forming a discharge interval (7); a resilient member (5) being sleeved on the pump shaft (4), one end of the resilient member (5) abutting against the impeller disc (3), the other end of the resilient member (5) abutting against the inner cavity of the pump body (1); a driving member (6) being arranged on the side of the impeller disc (3) away from the impeller cover (2), the driving end of the driving member (6) abutting against the impeller disc (3), the resilient member (5) and the driving member (6) being opposite in force.

2. A variable-displacement hydraulic pump for an engine according to claim 1, characterized by The cross-sectional dimension of the hole (31) is greater than the cross-sectional dimension of the blade (21), and the number and position of the holes (31) correspond to the number and position of the blades (21).

3. A variable-displacement hydraulic pump for an engine according to claim 1, characterized by The driving member (6) is an electromagnetic valve, the valve body of the electromagnetic valve being fixedly connected to the inner cavity wall surface of the pump body (1), the driving end of the electromagnetic valve being a valve core, the valve core extending to abut against the center of the impeller disc (3) along the axial direction of the pump shaft (4).

4. A variable-displacement hydraulic pump for an engine according to claim 3, characterized by The end of the valve core is provided with a semispherical protrusion abutting against the center of the impeller disc (3).

5. A variable-displacement hydraulic pump for an engine according to claim 3, wherein A wear-resistant gasket is clamped between the valve core and the impeller disc (3).

6. A variable- displacement hydraulic pump for an engine according to claim 5, wherein The outer diameter of the wear-resistant gasket is greater than the diameter of the end of the valve core.

7. A variable-displacement hydraulic pump for an engine according to claim 1, wherein The engine variable displacement water pump further comprises: a controller being electrically connected with the driving member (6), the controller being configured to control the on-off of the driving member (6) according to the engine speed.

8. A variable- displacement hydraulic pump for an engine according to claim 1, wherein The impeller cover (2) is disc-shaped, the blades (21) extending along the radial direction of the impeller cover (2), and a plurality of the blades (21) being uniformly and spacedly distributed in the circumferential direction of the impeller cover (2).

9. A water pump displacement control method for controlling the displacement of the variable displacement water pump for an engine according to any one of claims 1 to 8, characterized by The water pump displacement control method comprises: obtaining the current engine speed and comparing the current engine speed with a preset speed threshold; controlling the on-off of the driving member (6) according to the comparison result to adjust the axial spacing of the discharge interval (7) between the impeller disc (3) and the impeller cover (2).

10. A water pump displacement control method according to claim 9, characterized by, Further comprising: if the current engine speed is less than or equal to the preset speed threshold, the driving member (6) is controlled to be in the power-off state, the axial spacing of the discharge interval (7) between the impeller disc (3) and the impeller cover (2) being a first spacing, and the water pump working at a first displacement. If the current rotating speed of the engine is greater than a preset rotating speed threshold, the control drives the driving member (6) to be in an energized state, an axial distance of a liquid discharge gap (7) between the impeller disc (3) and the impeller cover (2) is a second distance, and the water pump works at a second displacement; Wherein, the first distance is greater than the second distance, and the first displacement is greater than the second displacement.

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