A method for regulating an oil injector

Abstract

The present disclosure relates to a fuel injector control method, comprising: arranging a valve sleeve between a regulating valve and a needle valve assembly, a first cavity being defined between the regulating valve and the valve sleeve, and a second cavity being defined between the needle valve assembly and the valve sleeve; wherein the valve sleeve is provided with a first hole, a second hole and a third hole, the first hole being communicated with the first cavity and the second cavity, the second hole being communicated with an outer peripheral wall of the valve sleeve and the first cavity, and the third hole being communicated with the outer peripheral wall of the valve sleeve and the second cavity; when the fuel injector switches from an open state to a closed state, oil flowing into the second hole flows into the second cavity after flowing through the first cavity and the first hole. The control method of the present disclosure can solve the problem of slow closing speed of the needle valve, ensure the accuracy, repeatability and durability of the fuel injection quantity of the fuel injector, and improve the injection rate curve.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the field of engine technology, and more particularly to a fuel injector control method. Background Technology

[0002] A fuel injector is a precision device that receives fuel injection pulse signals from the ECU to accurately control the amount of fuel injected. However, in existing technologies, for low-pressure injection conditions below 100 bar, the needle valve of the fuel injector closes slowly, making it difficult to guarantee the accuracy, repeatability, and durability of the fuel injection quantity. Summary of the Invention

[0003] This disclosure aims to at least partially address one of the technical problems in the aforementioned background or related technologies.

[0004] To address this issue, this disclosure proposes an injector control method that solves the problem of slow needle valve closing speed, ensuring the accuracy, repeatability, and durability of the injector's fuel injection quantity, and improving the injection rate curve.

[0005] The injector control method disclosed herein includes: A valve sleeve is provided between a regulating valve and a needle valve assembly, wherein a first cavity is defined between the regulating valve and the valve sleeve, and a second cavity is defined between the needle valve assembly and the valve sleeve; The valve sleeve is provided with a first hole, a second hole and a third hole. The first hole connects the first cavity and the second cavity, the second hole connects the outer peripheral wall of the valve sleeve and the first cavity, and the third hole connects the outer peripheral wall of the valve sleeve and the second cavity. When the injector switches from the open state to the closed state, the oil flowing in from the second hole flows through the first chamber and the first hole before flowing into the second chamber.

[0006] In some technical solutions, when the injector switches from a closed state to an open state, the oil flowing in from the second hole flows into the return oil passage in the regulating valve after passing through the first chamber.

[0007] In some technical solutions, the oil flowing from the third hole into the second chamber flows through the first hole and the first chamber before flowing into the return oil channel when the injector switches from the closed state to the open state.

[0008] In some technical solutions, the oil flows from the third hole into the second chamber when the injector switches from the open state to the closed state.

[0009] In some technical solutions, the diameter of the first hole is different from the diameter of the second hole; And / or, the diameter of the first hole is different from the diameter of the third hole; And / or, the diameter of the return oil passage of the regulating valve is larger than the diameter of the first orifice.

[0010] In some technical solutions, the flow direction of the oil in the first orifice is opposite when the injector switches from the closed state to the open state and when the injector switches from the open state to the closed state.

[0011] In some technical solutions, the needle valve assembly includes a needle valve and a sleeve, wherein the sleeve is fitted onto the outer periphery of the needle valve; The injector switches between the open and closed states by the reciprocating movement of the needle valve within the sleeve.

[0012] In some technical solutions, during the process of the injector switching from the closed state to the open state, the needle valve has a first moving speed; During the process of the injector switching from the open state to the closed state, the needle valve has a second moving speed; The first moving speed is different from the second moving speed.

[0013] In some technical solutions, the second moving speed is increased by increasing the ratio of the radial dimension of the first hole to the radial dimension of the third hole.

[0014] In some technical solutions, while keeping the flow rate ratio of the first hole and the third hole constant, the second moving speed is increased by reducing the absolute value of the flow rate of the first hole and the third hole.

[0015] Beneficial effects: The injector control method disclosed herein improves the problem of slow needle valve closing speed, ensures the accuracy, repeatability and durability of injector injection quantity, and thus also improves the injection rate curve.

[0016] By optimizing the opening and closing characteristics of the injector needle valve, an ideal fuel injection pattern (a boot shape injection rate curve with a "slow start and fast finish") is created, thereby actively managing the combustion heat release rate and breaking the contradiction between emissions and efficiency in traditional combustion. Attached Figure Description

[0017] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings consistently denote the same parts, wherein: Figure 1 This is an assembly diagram of the regulating valve, needle valve assembly, and valve sleeve of the injector according to this disclosure.

[0018] Figure 2 This is an assembly diagram of the solenoid valve assembly of the injector according to this disclosure.

[0019] Figure 3 This is a schematic diagram illustrating the switching of an injector from an open state to a closed state according to this disclosure.

[0020] Figure 4 This is a schematic diagram illustrating the switching of an injector from a closed state to an open state according to this disclosure.

[0021] Figure 5 This is a schematic diagram of the internal structure of the valve sleeve of the injector according to this disclosure.

[0022] Figure 6 This is a schematic diagram of the variable diameter groove section according to this disclosure.

[0023] Figure 7 This is a schematic diagram showing the position of the needle valve relative to the sub-slot when it is closed, according to this disclosure.

[0024] Figure 8 This is a schematic diagram showing the position of the needle valve relative to the sub-slot when it is open, according to this disclosure.

[0025] Figure 9 This is a schematic diagram of the sub-groove in a cross section perpendicular to the axial direction according to the present disclosure.

[0026] Figure label: 1-Regulating valve; 11-Return oil passage; 2-Needle valve assembly; 21-Needle valve; 22-Sleeve; 221-Curved surface; 3-Valve sleeve; 31-First groove; 32-Second groove; 321-Straight groove section; 322-Variable diameter groove section; 3221-First variable diameter groove section; 3222-Second variable diameter groove section; 323-Annular groove; 324-Sub-groove; 33-First hole; 331-First variable diameter section; 332-Second variable diameter section; 333-Intermediate hole section; 34-Second hole; 341-First conical section; 35-Third hole; 351-Second conical section; 4-Solenoid valve assembly. Detailed Implementation

[0027] The technical solutions of this disclosure will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of this disclosure with reference to the accompanying drawings is intended to explain the overall inventive concept of this disclosure and should not be construed as a limitation thereof.

[0028] The injector control method disclosed herein includes: A valve sleeve 3 is provided between the regulating valve 1 and the needle valve assembly 2, defining a first cavity between the regulating valve 1 and the valve sleeve 3, and defining a second cavity between the needle valve assembly 2 and the valve sleeve 3.

[0029] For example, such as Figure 1 As shown, the regulating valve 1 can be a flat cylindrical structure, and it is assembled inside the injector housing. The needle valve assembly 2 can be located below the regulating valve 1 and spaced apart from it. A portion of the needle valve assembly 2 can move relative to the injector housing, thereby enabling the sealing or opening of the injection port at the bottom of the injector.

[0030] The top side of the valve sleeve 3 can be provided with a first groove 31, and the bottom side of the valve sleeve 3 can be provided with a second groove 32. During installation, the valve sleeve 3 can be directly assembled between the regulating valve 1 and the needle valve assembly 2. The opening of the first groove 31 facing upward can be blocked by the regulating valve 1, thereby restricting the first cavity. The opening of the second groove 32 facing downward can be blocked by the needle valve assembly 2, thereby restricting the second cavity.

[0031] It should be noted that the various orientations in this disclosure can be the orientations of the injector in actual use, but do not represent a limitation on specific directions. For example, the axis of the injector can be vertical. In this case, the left side from bottom to top is left, the right side from bottom to top is right, the front side from bottom to top is front, and the rear side from bottom to top is rear.

[0032] The valve sleeve 3 is provided with a first hole 33, a second hole 34 and a third hole 35. The first hole 33 connects the first cavity and the second cavity, the second hole 34 connects the outer peripheral wall of the valve sleeve 3 and the first cavity, and the third hole 35 connects the outer peripheral wall of the valve sleeve 3 and the second cavity.

[0033] For example, such as Figure 1 As shown, the first hole 33 can extend in the vertical direction, the top end of the first hole 33 can be connected to the first cavity, and the bottom end of the first hole 33 can be connected to the second cavity.

[0034] The second hole 34 can be located at the top of the valve sleeve 3, specifically on the outer periphery of the first cavity. The inner opening of the second hole 34 can communicate with the first cavity, and the outer opening of the second hole 34 can communicate with the outer periphery of the valve sleeve 3.

[0035] The third hole 35 can be located at the bottom of the valve sleeve 3, specifically on the outer periphery of the second cavity. The inner opening of the third hole 35 can communicate with the second cavity, and the outer opening of the third hole 35 can communicate with the outer periphery of the valve sleeve 3.

[0036] It should be noted that, as Figure 2As shown, the injector may also include a solenoid valve assembly 4, which may be located on the top side of the regulating valve 1. The solenoid valve assembly 4 may include structural components such as a ceramic ball and an electromagnet. The solenoid valve assembly 4 can block or unblock the return oil passage 11 in the regulating valve 1. For example, when the solenoid valve assembly 4 is not energized, the electromagnet can press the ceramic ball downwards, and the pressed ceramic ball can block the return oil passage 11 in the regulating valve 1. When it is necessary to unblock the return oil passage 11, the solenoid valve assembly 4 can be energized. After energization, the electromagnet can be lifted, and at this time, the ceramic ball will move upwards and open.

[0037] When the injector switches from the open state to the closed state, the oil flowing in from the second hole 34 flows through the first chamber and the first hole 33 before flowing into the second chamber.

[0038] The injector is in the open state when it sprays fuel outwards, and the injector is in the closed state when it closes the bottom nozzle to prevent fuel from being sprayed.

[0039] like Figure 3 As shown, when it is necessary to close the fuel injector's bottom nozzle, the return oil passage 11 can be blocked by the solenoid valve assembly 4. At this time, the high-pressure oil in the injector housing will flow into the first chamber through the second hole 34 and into the second chamber through the third hole 35. Under the action of the high-pressure oil in the first and second chambers, the needle valve assembly 2 will move downward and maintain the position of blocking the fuel injector.

[0040] The oil flowing in through the second hole 34 passes sequentially through the first chamber and the first hole 33 before entering the second chamber. This replenishment of oil through the second hole 34 avoids the situation where insufficient oil pressure in the second chamber, which can lead to slow movement of the needle valve 21, is common with only the third hole 35. This ensures the injector's working efficiency and stability, thereby guaranteeing the accuracy, repeatability, and durability of the injector's injection volume and improving the injection rate curve.

[0041] like Figure 4 As shown, when the injector needs to inject oil, the blockage of the return oil channel 11 can be released by the solenoid valve assembly 4. At this time, the high-pressure oil in the first and second chambers will flow out to the low-pressure area through the return oil channel 11. Since the hydraulic action of the high-pressure oil in the first and second chambers is released, the needle valve assembly 2 will move upward, thereby opening the bottom injection port and realizing oil injection.

[0042] In some embodiments, the control method includes: when the injector switches from a closed state to an open state, the oil flowing in from the second hole 34 flows into the return oil passage 11 in the regulating valve 1 after passing through the first chamber.

[0043] For example, such as Figure 4As shown, when the injector switches to the open state, the oil outside the valve sleeve 3 flows into the first chamber through the second hole 34 and then flows out directly through the return oil channel 11 in the regulating valve 1. This causes the hydraulic pressure in the first chamber to drop sharply. Then the oil in the second chamber flows into the first chamber through the first hole 33 and then into the return oil channel 11.

[0044] Due to the sudden drop in hydraulic pressure in the second chamber, the needle valve 21 of the needle valve assembly 2 will move upward, thereby releasing the seal of the needle valve 21 on the injection port at the bottom of the injector.

[0045] In some embodiments, the control method includes: when the injector switches from a closed state to an open state, the oil flowing into the second chamber from the third hole 35 flows into the return oil channel 11 after passing through the first hole 33 and the first chamber.

[0046] For example, such as Figure 4 As shown, when the return oil passage 11 in the regulating valve 1 is opened, the oil in the first chamber will flow into the return oil passage 11, and then the oil in the second chamber at the bottom through the third hole 35 will continue to flow into the first chamber through the first hole 33. After merging with the oil flowing in through the second hole 34, both can flow out through the return oil passage 11.

[0047] This satisfies the requirement to quickly drain the oil from the first and second chambers to drive the needle valve 21 upwards.

[0048] In some embodiments, the control method includes: when the injector switches from an open state to a closed state, oil flows into the second chamber from the third hole 35.

[0049] For example, such as Figure 3 As shown, when the injector switches to the closed state, a portion of the oil on the outer periphery of the valve sleeve 3 can flow directly into the second chamber through the third hole 35, thereby increasing the hydraulic pressure in the second chamber. At the same time, another portion of the oil on the outer periphery of the valve sleeve 3 can flow into the first chamber through the second hole 34, and then flow into the second chamber through the first hole 33.

[0050] In the first chamber, the oil flowing in through the second hole 34 and the third hole 35 mixes and builds pressure, which drives the needle valve 21 to move down, thereby satisfying the need to close the injection port at the bottom of the injector.

[0051] In some embodiments, the diameter of the first hole 33 is different from the diameter of the second hole 34. For example, both the first hole 33 and the second hole 34 can be circular holes, wherein the diameter of the first hole 33 can be larger than the diameter of the second hole 34, thereby facilitating the reciprocating flow of oil between the first chamber and the second chamber.

[0052] In some embodiments, the diameter of the first hole 33 is different from the diameter of the third hole 35. For example, both the first hole 33 and the third hole 35 can be circular holes, wherein the diameter of the first hole 33 can be larger than the diameter of the third hole 35. The larger diameter of the first hole 33 facilitates the reciprocating flow of oil between the first chamber and the second chamber.

[0053] In some embodiments, the diameter of the return oil passage 11 of the regulating valve 1 is larger than the diameter of the first orifice 33. For example, as Figure 1 As shown, both the return oil channel 11 and the first hole 33 can be circular holes. The diameter of the return oil channel 11 is larger than that of the first hole 33, which allows the oil in the first chamber to be discharged quickly, which is beneficial to improving the response rate of the needle valve 21 moving upward, and thus improving the opening speed of the injector.

[0054] In some embodiments, the flow direction of the oil in the first orifice 33 is opposite when the injector switches from the closed state to the open state and when the injector switches from the open state to the closed state.

[0055] For example, such as Figure 3 As shown, when the injector switches to the open state, the flow direction of the oil in the first hole 33 can be from bottom to top, and when the injector switches to the closed state, the flow direction of the oil in the first hole 33 can be from top to bottom.

[0056] This difference in flow direction fully satisfies the need for rapid oil discharge when the device is open, and also satisfies the need for auxiliary pressure building in the second chamber by the oil flowing in through the second hole 34 when the device is closed.

[0057] In some embodiments, the needle valve assembly 2 includes a needle valve 21 and a sleeve 22, with the sleeve 22 fitted to the outer periphery of the needle valve 21. The reciprocating movement of the needle valve 21 within the sleeve 22 drives the injector to switch between an open and closed state.

[0058] For example, such as Figure 1 As shown, the needle valve 21 can be a straight rod, and the sleeve 22 can be a cylindrical shape. The needle valve 21 can be slidably assembled inside the sleeve 22. A spring or other elastic element can also be assembled at the bottom of the sleeve 22.

[0059] In use, the needle valve 21 can reciprocate in the vertical direction relative to the sleeve 22. When the needle valve 21 moves upward under hydraulic pressure, the bottom end of the needle valve 21 can release the seal on the injection port, thereby allowing the injector to switch to the open state. When the needle valve 21 moves downward under hydraulic pressure, the bottom end of the needle valve 21 can be inserted into the injection port, thereby allowing the injector to switch to the closed state.

[0060] In some embodiments, during the process of the injector switching from a closed state to an open state, the needle valve 21 has a first moving speed. This first moving speed can be the average speed of the needle valve 21 when it moves upwards.

[0061] During the process of the injector switching from the open state to the closed state, the needle valve 21 has a second moving speed. The second moving speed can be the average speed of the needle valve 21 when it moves downward.

[0062] The first moving speed differs from the second moving speed. For example, the first moving speed can be less than the second moving speed. Specifically, when the injector switches to the closed state, the oil flowing in through the second hole 34 flows downward along the first hole 33 into the second chamber, and the oil flowing in through the third hole 35 also flows directly into the second chamber. Under the combined action of the two liquids, the needle valve 21 can obtain a large acceleration, thereby meeting the requirement for the needle valve 21 to move quickly to close the injector port quickly.

[0063] In some other embodiments, the first moving speed and the second moving speed may be the same, or the first moving speed may be greater than the second moving speed.

[0064] In some embodiments, the second moving speed is increased by increasing the ratio of the radial dimension of the first hole 33 to the radial dimension of the third hole 35.

[0065] For example, the diameter of the first hole 33 can be A, and the diameter of the third hole 35 can be Z. In actual operation, by increasing the ratio of holes A / Z, the downward movement speed of the needle valve 21 can be increased, thereby meeting the usage requirement of driving the injector to quickly switch to the closed state.

[0066] In some embodiments, while keeping the flow ratio of the first orifice 33 and the third orifice 35 constant, the second moving speed is increased by reducing the absolute value of the flow rates of the first orifice 33 and the third orifice 35.

[0067] For example, the absolute value of the flow rate can be the flow rate through the corresponding orifice per unit time. Given the A / Z orifice ratio, by simultaneously reducing the absolute values ​​of the flow rates of the first orifice 33 and the third orifice 35, the pressure within the first chamber can be reduced. This allows the oil flowing in through the second orifice 34 to quickly flow into the second chamber through the first orifice 33. Under the action of this hydraulic pressure, the second moving speed can be increased, thereby meeting the requirement for the injector to quickly switch to the off state.

[0068] In some embodiments, the first hole 33 extends along the axis of the valve sleeve 3. For example, as Figure 5As shown, the valve sleeve 3 can be a cylindrical structure, and the axis of the valve sleeve 3 can be the central axis of the valve sleeve 3. The first hole 33 can extend along the axis of the valve sleeve 3, that is, the first hole 33 is located at the center of the valve sleeve 3.

[0069] This helps to achieve dynamic balance of oil flow and avoids the situation where the valve sleeve 3 is easily displaced due to uneven force distribution when the first hole 33 is eccentrically set.

[0070] In some embodiments, the second hole 34 is provided on the sidewall of the first groove 31 and extends radially along the valve sleeve 3, and the third hole 35 is provided on the sidewall of the second groove 32 and extends radially along the valve sleeve 3.

[0071] For example, such as Figure 5 As shown, the second hole 34 can be provided on the left side wall of the first groove 31 and extend in the left-right direction, and the third hole 35 can be provided on the right side wall of the second groove 32 and extend in the left-right direction.

[0072] This design allows the oil in the second hole 34 and the third hole 35 to flow in opposite directions. This opposite flow direction design can counteract the force generated by the flow, ensuring the stability of the structure and avoiding the mutual influence of the flow rate and pressure drop of the fluid in the second and third holes.

[0073] In some embodiments, the second groove 32 includes a straight groove section 321 and a variable diameter groove section 322. The straight groove section 321 extends along the axial direction of the valve sleeve 3. The first hole 33 is connected to the bottom wall of the straight groove section 321. The variable diameter groove section 322 is connected to the side of the straight groove section 321 away from the first hole 33. The radial dimension of the variable diameter groove section 322 increases in a direction away from the straight groove section 321. The groove wall of the variable diameter groove section 322 is used to abut against the needle valve assembly 2.

[0074] For example, such as Figure 5 As shown, the straight groove section 321 can be a flat cylindrical shape and extend along the vertical direction, the variable diameter groove section 322 can be generally frustoconical, the variable diameter groove section 322 can be connected to the bottom side of the straight groove section 321, and the radial dimension of the deformed groove section can gradually decrease along the direction from bottom to top.

[0075] Therefore, in use, the needle valve assembly 2 can be inserted into the variable diameter groove section 322, and the inserted needle valve assembly 2 can fit and abut against the inner wall of the variable diameter groove section 322, thereby achieving the sealing of the second cavity. The gradual change in the radial dimension of the variable diameter groove section 322 facilitates the insertion of the needle valve assembly 2.

[0076] In some embodiments, such as Figure 6As shown, the variable diameter groove section 322 can be divided into two groove sections, namely the first variable diameter groove section 3221 and the second variable diameter groove section 3222. The first variable diameter groove section 3221 can be... Figure 6 The portion shown in the red conical surface, the second variable diameter groove section 3222 can be Figure 6 The portion shown in the green cone.

[0077] The red conical surface (first variable diameter groove section 3221) and the spherical surface of the cylinder valve in the needle valve assembly form a cone-ball fitting seal structure, which can improve the surface contact fit of the sealing surface, effectively enhance the sealing reliability of this area under the alternating working pressure of the injector, and suppress the potential for fuel leakage; thereby ensuring the stable establishment of injection pressure and the precise control of injection accuracy, which helps to improve the fuel injection consistency and working stability of the injector.

[0078] The green conical surface (second variable diameter groove section 3222) serves as a grinding avoidance structure, which can prevent the grinding tool from interfering with the non-machined area of ​​the groove during the machining of the variable diameter groove section. This not only ensures the machining accuracy of functional areas such as the red conical surface, but also improves the smoothness of the machining operation and reduces the machining difficulty of this groove section.

[0079] In some embodiments, the second groove 32 includes an annular groove 323, which is disposed at the edge of the bottom wall of the straight groove section 321 and extends circumferentially along the straight groove section 321, and the annular groove 323 surrounds the outer periphery of the first hole 33.

[0080] For example, such as Figure 5 As shown, the annular groove 323 can be circular, and its cross-section can be approximately triangular. The annular groove 323 can be located at the edge of the bottom wall of the groove on the top side of the straight groove section 321, and the annular groove 323 can extend circumferentially along the bottom wall of the groove. The aforementioned first hole 33 can be located within the area enclosed by the annular groove 323 and is generally concentrically arranged with the annular groove 323.

[0081] During use, the oil can flow into the annular groove 323, and the force of the oil can generate horizontal and equal force components in the annular groove 323, thereby improving the stability of the valve sleeve 3.

[0082] In some embodiments, the second groove 32 includes a sub-groove 324, which is located at the connection between the straight groove section 321 and the variable diameter groove section 322, and the sub-groove 324 is connected to the third hole 35.

[0083] For example, such as Figure 5As shown, the cross-section of the sub-groove 324 can be roughly triangular. Specifically, the sub-groove 324 can be located on the right side of the connection between the straight groove section 321 and the variable diameter groove section 322. A part of the sub-groove 324 can be embedded in the straight groove section 321, and another part of the sub-groove 324 can be embedded in the variable diameter groove section 322.

[0084] The sub-groove 324 can be located to the left of the third hole 35. The oil flowing in through the third hole 35 can first flow into the sub-groove 324, and then flow into the straight groove section 321 and the variable diameter groove section 322.

[0085] The sub-groove 324 can achieve the effect of initial diffusion of oil, thereby slowing down the flow rate and allowing the oil to be evenly distributed to the straight groove section 321 and the variable diameter groove section 322.

[0086] Secondly, the sub-slot can also act as a buffer volume, preventing fuel from impacting the control lever (needle valve) when the valve is open.

[0087] In addition, the sub-groove 324 can also limit the length of the straight section of the third hole 35 (the narrow straight section in the middle of the third hole 35), so that the length of the straight section of the third hole 35 can meet the needs of optimizing the injection rate curve.

[0088] In some embodiments, such as Figure 7 As shown, when the needle valve 21 closes the bottom injection port, the top of the needle valve 21 is a certain distance away from the bottom wall of the second groove 32. The sub-groove 324 can be located roughly between the top of the needle valve 21 and the bottom wall of the second groove 32.

[0089] like Figure 8 As shown, when the needle valve 21 releases the seal on the bottom injection port, the top of the needle valve 21 moves toward the bottom wall of the second groove 32, and a part of the needle valve 21 can penetrate into the sub-groove 324.

[0090] like Figure 9 As shown, the sub-slot 324 can be arranged to extend circumferentially along the valve sleeve 3, thereby enabling the sub-slot 324 to cover a wider angle and area.

[0091] In some embodiments, such as Figure 5 As shown, the first hole 33 includes a first variable diameter section 331, a second variable diameter section 332, and an intermediate hole section 333.

[0092] The first variable diameter section 331 is connected to the first groove 31, and the radial dimension of the first variable diameter section 331 gradually decreases along the direction away from the first groove 31. For example, as Figure 5 As shown, the first variable diameter section 331 can be frustoconical in shape, and the radial dimension of the first variable diameter section 331 can gradually decrease from top to bottom.

[0093] The second variable diameter section 332 is connected to the second groove 32, and at least a portion of the radial dimension of the second variable diameter section 332 gradually decreases along the direction away from the second groove 32. For example, as Figure 5 As shown, the second variable diameter section 332 can be frustoconical in shape, and the radial dimension of the second variable diameter section 332 can gradually increase from top to bottom.

[0094] The intermediate hole section 333 connects the first variable diameter section 331 and the second variable diameter section 332. For example, as shown... Figure 5 As shown, the intermediate hole segment 333 can be a straight hole, and it can extend in the vertical direction. The top end of the intermediate hole segment 333 can be connected to the first diameter-changing segment 331, and the bottom end can be connected to the second diameter-changing segment 332. The aforementioned aperture A can be regarded as the aperture of the intermediate hole segment 333.

[0095] When the oil flows out from the first diameter-changing section 331 and the second diameter-changing section 332, the flow rate of the oil will slow down due to the gradual expansion effect of the diameter change, so that the oil can diffuse relatively uniformly into the first tank 31 or the second tank 32.

[0096] Secondly, the first variable diameter section 331 and the second variable diameter section 332 can also limit the length of the intermediate hole section 333, thereby meeting the needs of optimizing the injection rate curve.

[0097] In addition, the aforementioned first diameter-reducing section 331 can buffer and dissipate energy during use, allowing bubbles to collapse smoothly, avoiding concentrated impact on the borehole wall, and significantly reducing cavitation erosion damage. The aforementioned second variable diameter section 332 can be used as an initial guiding section for the fluid, regulating the flow pattern, ensuring a smooth transition, reducing initial turbulent disturbances, and laying the foundation for a stable flow field. The aforementioned intermediate orifice section 333 can be used as a transitional adjustment section for pressure and flow rate. Through the adaptation design of the orifice diameter, the rate of change of fuel flow rate can be controlled to maintain pressure stability.

[0098] In some embodiments, both the inlet of the second hole 34 and the third hole 35 are provided with a tapered section, and the radial dimension of the tapered section gradually decreases along the direction close to the axis of the valve sleeve 3.

[0099] For example, such as Figure 5 As shown, the inlet of the second hole 34 is provided with a first conical section 341, the radial dimension of the first conical section 341 gradually decreases from left to right, and the inlet of the third hole 35 is provided with a second conical section 351, the radial dimension of the second conical section 351 gradually decreases from right to left.

[0100] The tapered section facilitates the flow of oil from outside the valve sleeve 3 into the second hole 34 and the third hole 35. Secondly, it also helps to limit the length of the straight sections of the second hole 34 and the third hole 35.

[0101] In some embodiments, the regulating valve 1 is provided with an oil return channel 11, which is connected to the first cavity and is coaxially arranged with the first hole 33.

[0102] For example, such as Figure 1 As shown, the oil return channel 11 can be located at the center of the regulating valve 1. The oil return channel 11 can extend along the axis of the regulating valve 1 and penetrate the regulating valve 1 in the vertical direction. The bottom end of the oil return channel 11 can be directly connected to the first cavity. In the vertical direction, the oil return channel 11 can be arranged directly opposite the first hole 33.

[0103] Therefore, while satisfying the need to drain the oil from the first chamber, the symmetry of the flowing oil is also ensured, thus guaranteeing the stability of the overall structure.

[0104] In some embodiments, the radial dimension of the return oil passage 11 remains consistent along the axial direction of the regulating valve 1. For example, as Figure 1 As shown, the oil return channel 11 is a straight channel, meaning that the radial dimension of the oil return channel 11 remains constant along the vertical direction. This ensures good overall flowability.

[0105] In some embodiments, the needle valve assembly 2 includes a needle valve 21 and a sleeve 22, wherein the needle valve 21 can be a straight rod structure extending in the vertical direction. The sleeve 22 is sleeved on the outer periphery of the needle valve 21, and the needle valve 21 can reciprocate in the vertical direction relative to the sleeve 22, thereby meeting the need to seal or unseal the fuel injection port by means of the bottom end of the needle valve 21.

[0106] The end of the sleeve 22 facing the valve sleeve 3 is provided with a curved surface 221. The curved surface 221 is provided around the circumference of the sleeve 22 and is used to abut against the valve sleeve 3 to block the second cavity.

[0107] For example, such as Figure 1 As shown, the curved surface 221 can be located at the top of the sleeve 22. The curved surface 221 can be a convex surface and extends around the circumference of the sleeve 22. In use, the sleeve 22 and the needle valve 21 can be inserted into the second groove 32. The curved surface 221 on the sleeve 22 can fit and abut against the circumferential groove wall of the second groove 32, thereby achieving circumferential sealing and ensuring the sealing of the second cavity.

[0108] The following describes a specific example of the control method disclosed herein.

[0109] (1) Injector closed (stationary / accumulation state) Solenoid valve: De-energized. The armature of the solenoid valve assembly is pressed down by the spring, closing the oil return passage.

[0110] Fuel circuit: High-pressure fuel continuously enters the control chamber (second chamber) from the Z-hole (third hole), establishing pressure; high-pressure fuel also enters the transition chamber (first chamber) from the Z1-hole (second hole), establishing pressure. Result: Under the action of the oil pressure in the control chamber, the needle valve is pressed tightly downwards, overcoming the fuel pressure in the nozzle chamber, ensuring the injector is tightly closed, preventing dripping or abnormal injection.

[0111] (2) Injector turned on (injection state) Solenoid valve: Energized. The armature is attracted by electromagnetic force, opening the oil return passage.

[0112] Oil circuit: The high-pressure fuel in the control chamber is immediately discharged at high speed through hole A (first hole) to the transition chamber; the discharged fuel merges with the fuel from hole Z1 in the transition chamber, and together they flow back to the fuel tank through the return oil hole on the regulating valve opened by the solenoid valve.

[0113] Result: The pressure inside the control chamber dropped sharply. The needle valve quickly lifted, and oil injection began.

[0114] (3) Fuel injection ends (needle valve closes) Solenoid valve: De-energized. The oil return passage is closed again.

[0115] Fuel circuit: Fuel from Z-hole and Z1-hole rapidly refills the control chamber and transition chamber.

[0116] Result: The pressure inside the control chamber rises rapidly, pushing the needle valve downwards, causing it to quickly and decisively settle and end the injection. By precisely controlling the flow rate through the Z1 orifice, the speed of this "refilling" can be adjusted, thereby controlling the closing speed of the needle valve and ensuring low-pressure injection performance.

[0117] The control method disclosed herein determines the pressure value within the injector control chamber by the interaction between orifice A (first orifice) and orifice Z (third orifice) when the injector is open. This pressure value is a key factor in determining the start time and injection quantity of the injector. In the normal state, the oil in orifice Z1 (second orifice) will be directly returned through the return oil hole and will not participate in the injector's injection process.

[0118] When the injector closes, the return oil passage also closes. At this time, the oil from orifice Z1 flows back into the control chamber through orifice A, replenishing the control chamber. This process accelerates the descent speed of the control lever, effectively compensating for the problems of insufficient oil supply to the control chamber due to the small flow rate of orifice Z and the slow injector closing speed. By replenishing oil in reverse during the closing condition, the injector closing performance is ensured to meet the standards, guaranteeing a smooth injector closure.

[0119] Secondly, the control method disclosed herein innovatively introduces the concept of a variable A / Z ratio, where Z can be considered as the entirety formed by the second and third orifices. By adjusting the second orifice, a variable A / Z ratio is achieved. This overcomes the limitations of existing technologies, namely, that the fixed needle valve opening speed of existing technologies cannot perfectly adapt to all engine operating conditions. Especially in low-pressure injection conditions below 100 bar, it achieves precise control of the needle valve closing speed, thereby ensuring the accuracy, repeatability, and injector durability of ultra-low injection quantities.

[0120] The regulating valve sleeve disclosed herein is responsible for pressure control, the sleeve is responsible for guiding and sealing, and the regulating valve is responsible for connecting and blocking the return oil channel. The division of labor is clear, which effectively reduces the structural complexity and manufacturing difficulty of individual parts, improves the production qualification rate and consistency, and reduces manufacturing costs. Each functional module is independent of each other, realizing fault isolation, which facilitates later maintenance and replacement, and improves the reliability and maintainability of the product.

[0121] It achieves precise and flexible control of the combustion process, making it closer to the theoretically efficient combustion (maximally mimicking and approximating the optimal combustion state described by the ideal Otto cycle). Furthermore, by optimizing the opening and closing characteristics of the injector needle valve, it can shape an ideal fuel injection pattern (a "slow-to-fast" boot shape injection rate curve), thereby actively managing the combustion heat release rate and breaking the contradiction between emissions and efficiency in traditional combustion.

[0122] In addition, it helps to solve the dilemma of balancing NOx (nitrogen oxides) and soot (carbon soot), the contradiction between combustion noise and efficiency, the bottleneck of fuel economy, and the poor effect of injection or late injection.

[0123] It should be noted that, in this disclosure, each numerical range, except where it is explicitly stated that it does not include endpoint values, can be either endpoint values ​​or the median of each numerical range. Furthermore, the specific numerical values ​​in this disclosure are not intended to limit the corresponding size parameters in this disclosure, and all allowed values ​​are within the protection scope of this disclosure.

[0124] Although embodiments of the present disclosure have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlling a fuel injector, comprising: A valve sleeve is provided between a regulating valve and a needle valve assembly, wherein a first cavity is defined between the regulating valve and the valve sleeve, and a second cavity is defined between the needle valve assembly and the valve sleeve; The valve sleeve is provided with a first hole, a second hole and a third hole. The first hole connects the first cavity and the second cavity, the second hole connects the outer peripheral wall of the valve sleeve and the first cavity, and the third hole connects the outer peripheral wall of the valve sleeve and the second cavity. When the injector switches from the open state to the closed state, the oil flowing in from the second hole flows through the first chamber and the first hole before flowing into the second chamber.

2. The injector control method according to claim 1, comprising: When the injector switches from the closed state to the open state, the oil flowing in from the second hole flows into the return oil passage in the regulating valve after passing through the first chamber.

3. The injector control method according to claim 2, comprising: When the injector switches from the closed state to the open state, the oil flowing into the second chamber from the third hole flows through the first hole and the first chamber before flowing into the return oil channel.

4. The injector control method according to claim 1, comprising: When the injector switches from the open state to the closed state, the oil flows into the second chamber from the third hole.

5. The injector control method according to claim 1, wherein the diameter of the first hole is different from the diameter of the second hole; And / or, the diameter of the first hole is different from the diameter of the third hole; And / or, the diameter of the return oil passage of the regulating valve is larger than the diameter of the first orifice.

6. The injector control method according to claim 1, wherein when the injector switches from a closed state to an open state and when the injector switches from an open state to a closed state, the flow direction of the oil in the first orifice is opposite.

7. The injector control method according to any one of claims 1-6, wherein the needle valve assembly comprises a needle valve and a sleeve, the sleeve being assembled on the outer periphery of the needle valve; The injector switches between the open and closed states by the reciprocating movement of the needle valve within the sleeve.

8. The injector control method according to claim 7, During the process of the injector switching from the closed state to the open state, the needle valve has a first moving speed; During the process of the injector switching from the open state to the closed state, the needle valve has a second moving speed; The first moving speed is different from the second moving speed.

9. The injector control method according to claim 8, wherein the second moving speed is increased by increasing the ratio of the radial dimension of the first hole to the radial dimension of the third hole.

10. The injector control method according to claim 8, While keeping the flow rate ratio of the first orifice and the third orifice constant, the second moving speed is increased by reducing the absolute value of the flow rate of the first orifice and the third orifice.

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