Split control valve and oil sprayer

Abstract

The utility model provides a kind of split control valve and oil atomizer.The split control valve is composed of upper and lower split structure by valve sleeve and valve seat, valve sleeve has two-stage outer diameter of small diameter of lower end, large diameter of upper end, large diameter end face is equipped with two-stage sealing ring belt and ring groove, and also be equipped with guide hole and other various pore channels;Valve seat has sealing cone surface, oil outlet hole and other structures, both form transition chamber Q together.The split control valve is applied to oil atomizer, and oil atomizer includes shell, valve screw and other components.The split control valve of the utility model realizes many technical effects by optimizing oil return flow channel structure: transition chamber Q reduces main stream area flow velocity, inhibits cavitation, prolongs oil atomizer life;Two-stage sealing ring belt and ring groove improve high-pressure sealing reliability, and oil product is suitable for a wide range;Split structure reduces processing difficulty, is convenient for maintenance;Oil return transition hole cooperates with gradually reducing diffusion hole, and improves oil atomization precision.

Description

Technical Field

[0001] This utility model belongs to the technical field of fuel injection in internal combustion engines, and particularly relates to a split control valve and fuel injector. Background Technology

[0002] The fuel injector injects high-pressure fuel into the combustion chamber, and its opening and closing are controlled by a control valve. The control chamber formed by the inner hole of the control valve sleeve 2 and the top of the control plunger 1, as well as the fuel inlet throttle orifice and the fuel outlet throttle orifice, are key parameters for controlling the fuel injection characteristics of the fuel injector.

[0003] The oil outlet throttling orifice at the upper end of the control chamber affects the oil discharge rate of the control chamber, thereby controlling the opening speed and lift of the needle valve.

[0004] In reality, ball valve sealing structures all suffer from cavitation problems at the oil outlet, especially when there is a high pressure difference between the inlet and outlet of the throttling orifice, where the cavitation problem is more severe. In ultra-high pressure injectors of 2500 bar and above, under ultra-high pressure differences, the flow area of ​​fuel suddenly shrinks when passing through the throttling orifice. At high flow rates, when the pressure drops to 0 bar, it is easier for bubbles to form. These bubbles adhere to the oil outlet and seat surface, causing cavitation damage and reducing the lifespan of the injector.

[0005] In the orifice inlet region, the fuel flow rate increases sharply while the fuel pressure decreases. When the pressure drops to the fuel saturated vapor pressure, bubbles will be generated. Since bubbles occupy a larger volume than liquid, the fuel pressure in the orifice will rise, resulting in an increased area of ​​bubble adhesion to the orifice wall. To reduce the risk of damage to the sealing surface due to cavitation, the flow channel structure can be improved and optimized to enhance flow uniformity and direct the cavitation-generating area to the center of the flow channel, away from the sealing surface. Summary of the Invention

[0006] To address the problems existing in the prior art, this utility model provides a split control valve that reduces the risk of cavitation by optimizing the return oil flow channel. This is mainly achieved by adding a narrow channel and a tapered orifice after the oil outlet throttling orifice to reduce the flow velocity in the mainstream area and weaken the local backflow at the oil outlet orifice, thereby suppressing the cavitation triggering conditions. Furthermore, the tapered orifice design ensures that the area where cavitation occurs is far away from the sealing seat surface.

[0007] This utility model is implemented as follows: a split control valve, characterized by: an upper and lower split structure consisting of a valve sleeve and a valve seat; the valve sleeve includes: a two-stage outer diameter structure with a lower small diameter and an upper large diameter, and a hollow structure at the junction of the large and small diameters; a high-pressure sealing structure on the large diameter end face: from the inside to the outside, a first sealing ring, an annular groove, and a second sealing ring are arranged sequentially, the area of ​​the first sealing ring is ≤12mm², and its inner side is provided with a groove with a diameter ≤φ3.5mm; a guide hole, a hollow hole, a return oil transition hole, and an oil outlet section are arranged axially. The valve sleeve includes a flow orifice and a first-stage diffuser orifice. One end of the first-stage diffuser orifice is connected to the oil outlet throttling orifice via a chamfered transition area, and the other end is connected to the groove. An oil inlet is provided on the small-diameter side. The valve seat includes a sealing cone surface, a transition chamfer, an oil outlet orifice, and a second-stage diffuser orifice in the top volume cavity. An inlet chamfer is provided at the junction of the bottom boss surface and the second-stage diffuser orifice. The outer diameter is guided to fit the middle hole of the housing. The first-stage diffuser orifice, the chamfered transition area, the groove, the inlet chamfer of the valve seat, and the second-stage diffuser orifice together form a transition cavity Q.

[0008] More preferably, the diameter of the secondary diffuser hole of the valve seat is smaller than the diameter of the first-stage diffuser hole of the valve sleeve.

[0009] More preferably, the diameter of the boss surface of the valve seat is larger than the outer diameter of the second sealing ring of the valve sleeve.

[0010] More preferably, the diameter of the oil outlet hole of the valve seat is larger than the diameter of the oil outlet throttling hole of the valve sleeve, and a transition chamfer is provided between the oil outlet hole and the sealing cone surface.

[0011] More preferably, the outer diameter of the valve seat is the same as the major diameter of the valve sleeve.

[0012] More preferably, the inner and outer diameters of the annular groove are adjustable to distribute the sealing pressure ratio acting on the first sealing ring and the second sealing ring.

[0013] This utility model also discloses an injector, characterized in that it comprises: a housing, a valve screw, a control plunger, a sealing ball, and the aforementioned split control valve; wherein: the small diameter of the valve sleeve is placed in the accumulator cavity of the housing, and the large diameter is guided and fitted with the central hole of the housing; the tightening force of the valve screw acts on the boss surface of the valve seat and is transmitted to the shoulder surface of the valve sleeve, so that the shoulder surface is pressed against the inner end face of the housing; the control plunger, the guide hole, and the empty hole form a control cavity; the sealing ball and the sealing cone surface constitute a ball valve sealing pair.

[0014] More preferably, the length of the first-stage diffuser hole is greater than its diameter, so as to reduce the fuel flow rate and suppress local backflow at the oil outlet.

[0015] More preferably, the tapered structure of the secondary diffusion hole and the oil outlet hole keeps the cavitation generation area away from the sealing cone surface.

[0016] More preferably, the diameter of the return oil transition hole is larger than the diameter of the oil outlet throttling hole, so as to reduce the sensitivity of the oil outlet throttling hole to pressure fluctuations.

[0017] The advantages and technical effects of this utility model are as follows: This split control valve achieves the following technical effects by optimizing the return oil flow channel structure: The Q-design of the transition cavity reduces the flow velocity in the mainstream area, weakens the local backflow at the oil outlet orifice, suppresses the cavitation triggering conditions, and keeps the cavitation generation area away from the sealing surface, thus extending the service life of the injector. The two-stage sealing ring and groove structure improves the reliability of high-pressure sealing and makes it more adaptable to a wider range of oils; The split structure reduces the difficulty of machining complex oil passages, allows for the replacement of partial parts, and reduces maintenance costs. The oil return transition hole works in conjunction with the tapered diffuser hole to reduce the impact of pressure fluctuations on the injection pattern and improve injection accuracy. Attached Figure Description

[0018] Figure 1 This application describes an implementation of a split control valve for an injector. Figure 2 The transition cavity structure implemented in this application; Figure 3 The valve seat implemented in this application; Figure 4 The valve sleeve implemented in this application; Figure 5 This is a schematic diagram of the valve sleeve sealing surface structure implemented in this application.

[0019] In the diagram: 1. Control plunger; 2. Valve sleeve; 2a. Guide hole; 2b. Empty knife hole; 2c. Return oil transition hole; 2d. Oil outlet throttling hole; 2e. First-stage diffuser hole; 2f. Chamfered transition zone; 2g. Oil inlet hole; 20. Valve sleeve minor diameter; 21. Valve sleeve major diameter; 23. Empty knife structure; 24. Boss; 25. First sealing ring; 26. Second sealing ring; 27. Annular groove; 271. Annular groove inner diameter; 272. Annular groove outer diameter; 28. Groove; 3. Valve seat; 3a. Oil outlet hole; 3b. Transition chamfer; 3c. Second-stage diffuser hole; 3d. Inlet chamfer; 30. Sealing cone surface; 31. Boss surface; 32. Valve seat outer diameter; 4. Sealing ball; 5. Housing; 50. Accumulator chamber; 6. Valve screw. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0021] This utility model discloses a split control valve and its injector, and its embodiments, combined with structural features and technical effects, are described below: Example of a split control valve: The split control valve consists of an upper and lower split structure, with valve sleeve 2 and valve seat 3. Its core innovation lies in solving the cavitation problem through flow channel optimization and split sealing design.

[0022] Valve sleeve 2 structure and flow channel design: Valve sleeve 2 adopts a two-stage outer diameter structure: the lower small diameter 20 is placed inside the high-pressure accumulator chamber 50 of the housing 5, and the upper large diameter 21 is guided and matched with the central hole of the housing 5 to ensure the coaxiality of the control plunger 1 movement; a hollow structure 23 is provided at the junction of the large and small diameters to eliminate stress concentration at the shoulder. The end face of the large diameter 21 is provided with a high-pressure sealing structure, which consists of a first sealing ring 25, an annular groove 27, and a second sealing ring 26 from the inside to the outside. The area of ​​the first sealing ring 25 is ≤12mm², and a groove 28 with a diameter ≤φ3.5mm is provided on its inner side. The annular groove 27 achieves a reasonable distribution of sealing pressure between the first sealing ring 25 and the second sealing ring 26 by adjusting the size of the inner diameter 271 and the outer diameter 272 of the annular groove, thereby improving the sealing reliability under high pressure environment.

[0023] A flow channel is provided axially: the guide hole 2a cooperates with the control plunger 1 to ensure the smooth movement of the plunger 1; the air hole 2b forms a control cavity with the control plunger 1 to dynamically adjust the fuel injection pattern. The return transition hole 2c has a larger diameter than the outlet throttle hole 2d, reducing the sensitivity of the outlet throttle hole 2d to pressure fluctuations; a first-stage diffuser hole 2e is provided after the outlet throttle hole 2d, whose length is greater than its diameter, which can reduce the flow velocity in the mainstream area, improve flow uniformity, and reduce the local backflow phenomenon at the outlet orifice; one end of the first-stage diffuser hole 2e is connected to the outlet throttle hole 2d through the chamfered transition zone 2f to reduce fuel disturbance, and the other end is connected to the groove 28 to guide the airflow away from the sealing surface. An oil inlet hole 2g is opened on the side of the small diameter 20, which determines the dynamic pressure of the control cavity and controls the opening and closing of the needle valve by matching the diameter of the control plunger 1 and the diameter of the outlet throttle hole 2d.

[0024] Valve seat 3 structure and flow channel design: A sealing cone surface 30 and a sealing ball 4 form a ball valve sealing pair within the top volume cavity of the valve seat 3. Sealing is achieved when the sealing ball 4 contacts the sealing cone surface 30; oil injection begins when they separate. An oil outlet hole 3a is located at the lower end of the sealing cone surface 30, with a transition chamfer 3b between the oil outlet hole 3a and the sealing cone surface 30. A secondary diffuser hole 3c is located at the lower end of the oil outlet hole 3a. The diameter of the secondary diffuser hole is smaller than the diameter of the first-stage diffuser hole in the valve sleeve 2, forming a tapered structure that keeps the cavitation generation area away from the sealing cone surface 30. A boss surface 31 is located at the bottom of the valve seat 3, with an inlet chamfer 3d at the junction with the secondary diffuser hole 3c. The diameter of the boss surface is larger than the outer diameter of the second sealing ring of the valve sleeve 2, ensuring high-pressure sealing reliability. The outer diameter 32 of the valve seat is guided to the central hole of the housing 5 and is the same as the large diameter 21 of the valve sleeve 2, further improving coaxiality.

[0025] Structure and function of transition cavity Q: Transition cavity Q is jointly formed by the first-stage diffuser hole 2e, the chamfered transition zone 2f, the groove 28 of valve sleeve 2, the inlet chamfer 3d of valve seat 3, and the second-stage diffuser hole 3c. This structure reduces cavitation effect and suppresses cavitation triggering conditions by extending the length of the diffuser hole and optimizing the chamfered transition, while also allowing for the replacement of partial parts and reducing maintenance costs.

[0026] Injector Embodiment: An injector includes a housing 5, a valve screw 6, a control plunger 1, a sealing ball 4, and the aforementioned split control valve. The small diameter 20 of the valve sleeve 2 is placed within the pressure accumulator chamber 50 of the housing, while the large diameter 21 is guided and fitted with the central hole of the housing 5. The tightening force of the valve screw 6 acts on the boss surface 31 of the valve seat 3, and is transmitted to the shoulder surface 29 of the valve sleeve 2, causing the shoulder surface 29 to press tightly against the inner end face of the housing 5, achieving a high-pressure seal. The control plunger 1, the guide hole 2a of the valve sleeve 2, and the empty hole 2b form a control chamber. The sealing ball 4 and the sealing cone surface 30 of the valve seat 3 constitute a ball valve sealing pair, jointly completing the opening and closing control of the injector.

[0027] Working principle When the injector is operating, the control plunger 1 moves under the action of high-pressure fuel, changing the volume of the control chamber. When the sealing ball 4 disengages from the sealing cone surface 30 of the valve seat 3, the high-pressure fuel enters the control chamber through the inlet hole 2g, and returns through the outlet throttle hole 2d, the first-stage diffuser hole 2e, the transition chamber Q, and the second-stage diffuser hole 3c, forming a dynamic pressure balance. At this time, the needle valve opens, and fuel is injected into the combustion chamber. By optimizing the flow channel structure (such as the tapered orifice and the long diffuser hole), local flow velocity and pressure fluctuations are reduced, cavitation is suppressed, and the injector life is extended.

[0028] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A split-type control valve, characterized in that: The valve sleeve (2) and valve seat (3) are a split structure consisting of an upper and lower body; the valve sleeve (2) includes a two-stage outer diameter structure with a lower small diameter (20) and an upper large diameter (21), and a hollow knife structure (23) is provided at the junction of the large and small diameters. High-pressure sealing structure of the large diameter (21) end face: from the inside to the outside, the first sealing ring (25), the ring groove (27), and the second sealing ring (26) are arranged in sequence. The area of ​​the first sealing ring (25) is ≤12mm², and the inner side is provided with a groove (28) with a diameter ≤φ3.5mm. A guide hole (2a), a hollow hole (2b), a return oil transition hole (2c), an oil outlet throttling hole (2d), and a first-stage diffuser hole (2e) are provided through the axis. One end of the first-stage diffuser hole (2e) is connected to the oil outlet throttling hole (2d) via a chamfered transition area (2f), and the other end is connected to a groove (28). An oil inlet hole (2g) is opened on the side of the small diameter (20). The valve seat (3) includes: a sealing cone surface (30) in the top volume cavity, a transition chamfer (3b), an oil outlet (3a) and a secondary diffuser (3c); An inlet chamfer (3d) is provided at the junction of the bottom boss surface (31) and the secondary diffusion hole (3c); The outer diameter (32) of the valve seat is guided to fit the central hole of the housing (5); The first-stage diffusion hole (2e), chamfered transition area (2f), and groove (28) of the valve sleeve (2) together with the inlet chamfer (3d) and second-stage diffusion hole (3c) of the valve seat (3) form a transition cavity (Q).

2. The split control valve according to claim 1, characterized in that: The diameter of the secondary diffuser hole of the valve seat (3) is smaller than the diameter of the first-stage diffuser hole of the valve sleeve (2).

3. The split control valve according to claim 1, characterized in that: The diameter of the boss surface of the valve seat (3) is greater than the outer diameter of the second sealing ring of the valve sleeve (2).

4. The split control valve according to claim 1, characterized in that: The diameter of the oil outlet hole of the valve seat (3) is larger than the diameter of the oil outlet throttling hole of the valve sleeve (2), and a transition chamfer (3b) is provided between the oil outlet hole (3a) and the sealing cone surface (30).

5. The split control valve according to claim 1, characterized in that: The outer diameter (32) of the valve seat (3) is the same as the major diameter (21) of the valve sleeve (2).

6. The split control valve according to claim 1, characterized in that: The inner diameter (271) and outer diameter (272) of the annular groove (27) are adjustable to distribute the sealing pressure ratio acting on the first sealing ring (25) and the second sealing ring (26).

7. A fuel injector, characterized in that... It comprises: a housing (5), a valve screw (6), a control plunger (1), a sealing ball (4), and a split control valve as described in any one of claims 1-6; Wherein: the minor diameter (20) of the valve sleeve (2) is placed inside the accumulator cavity (50) of the housing, and the major diameter (21) is guided and matched with the central hole of the housing (5); The tightening force of the valve screw (6) acts on the boss surface (31) of the valve seat (3) and is transmitted to the shoulder surface (29) of the valve sleeve (2), so that the shoulder surface (29) is pressed against the inner end face of the housing (5); the control plunger (1) forms a control cavity with the guide hole (2a) and the empty knife hole (2b); the sealing ball (4) and the sealing cone surface (30) constitute the ball valve sealing pair.

8. The injector according to claim 7, characterized in that: The length of the first-stage diffuser hole (2e) is greater than its diameter to reduce the fuel flow rate and suppress local backflow at the outlet orifice.

9. The injector according to claim 7, characterized in that: The tapering structure of the secondary diffuser hole (3c) and the oil outlet hole (3a) keeps the cavitation generation area away from the sealing cone surface (30).

10. The injector according to claim 7, characterized in that: The diameter of the return oil transition hole (2c) is larger than that of the oil outlet throttling hole (2d) to reduce the sensitivity of the oil outlet throttling hole (2d) to pressure fluctuations.

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