Split control valve and oil sprayer

Abstract

The invention provides a split control valve and an oil sprayer. The split control valve is of an up-down split structure formed by a valve sleeve and a valve seat, the valve sleeve is provided with two-stage outer diameters, namely a small diameter at the lower end and a large diameter at the upper end, and the large-diameter end face is provided with two-stage sealing ring belts and ring grooves and is further provided with various hole channels such as guide holes. The valve seat is provided with a sealing conical surface, an oil outlet hole and the like which jointly form a transition cavity Q; the split control valve is applied to the fuel injector, and the fuel injector comprises a shell, a valve screw and the like. By optimizing the oil return flow channel structure, the split control valve has the advantages that the transition cavity Q reduces the flow speed of a main flow area, cavitation is restrained, and the service life of an oil sprayer is prolonged; the two-stage sealing ring belt and the ring groove improve the high-pressure sealing reliability, and the oil product application range is wide; the split structure reduces the processing difficulty and is convenient to maintain; and the oil return transition hole is matched with the gradually-shrinking diffusion hole, so that the oil injection precision is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel injection of internal combustion engines, and in particular relates to a split control valve and a fuel injector. Background Art

[0002] The fuel injector sprays high-pressure fuel into the combustion chamber, and the injector is controlled to open and close by the control valve.

[0003] 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 oil inlet throttle hole and the oil outlet throttle hole, are key parameters for achieving the control of the injection characteristics of the injector.

[0004] The oil outlet throttle hole at the upper end of the control chamber affects the oil leakage speed of the control chamber, thereby controlling the opening speed and lift of the needle valve.

[0005] In reality, ball valve sealing structures often experience cavitation at the oil outlet, a problem that is particularly severe when there's a high pressure differential between the orifice's inlet and outlet. In ultra-high-pressure injectors operating at 2500 bar and above, the flow area suddenly shrinks as the fuel passes through the orifice under these extremely high pressure differentials. At high flow rates, once the pressure drops to 0 bar, bubbles are more likely to form. These bubbles then attach to the oil outlet and seat, causing cavitation damage and shortening the injector's service life.

[0006] In the throttle hole inlet area, the fuel flow rate increases sharply, and the fuel pressure drops at the same time. When the pressure drops to the saturated vapor pressure of the fuel, bubbles are generated. Since bubbles occupy a larger volume than liquids, the fuel pressure in the throttle hole rises, resulting in an increase in the area of ​​bubbles adhering to the hole wall. In order to reduce the risk of damage to the sealing seat due to cavitation, the flow channel structure can be improved and optimized to improve flow uniformity, and the area where cavitation occurs can be directed to the center of the flow channel, away from the sealing seat. Summary of the Invention

[0007] In response to the problems existing in the prior art, the present invention provides a split control valve that reduces the risk of cavitation by optimizing the return oil flow channel. It mainly adds a narrow channel and a tapered hole after the oil outlet throttle hole to reduce the flow velocity in the mainstream area and weaken the local backflow of the oil outlet hole, thereby suppressing the cavitation triggering conditions. The tapered hole design makes the area where cavitation occurs away from the sealing seat surface.

[0008] The present invention is achieved in this way:

[0009] A split control valve, characterized by: comprising an upper and lower split structure consisting of a valve sleeve and a valve seat; the valve sleeve comprises: a two-stage outer diameter structure with a small diameter at the lower end and a large diameter at the upper end, with an empty knife structure at the intersection of the large and small diameters; a high-pressure sealing structure on the large diameter end face: a first sealing ring belt, a ring groove, and a second sealing ring belt are arranged in sequence from the inside to the outside, and the area of ​​the first sealing ring belt is ≤12mm2 , a groove is provided on its inner side with a diameter of ≤φ3.5mm; a guide hole, an empty knife hole, an oil return transition hole, an oil outlet throttling hole and a first-stage diffusion hole are arranged through the axial direction, one end of the first-stage diffusion hole is connected to the oil outlet throttling hole through the chamfered transition area, and the other end is connected to the groove; an oil inlet hole is provided on the side of the small diameter; the valve seat includes: a sealing cone surface, a transition chamfer, an oil outlet hole and a secondary diffusion hole in the top volume cavity; an inlet chamfer is provided at the intersection of the bottom boss surface and the secondary diffusion hole; the outer diameter is matched with the guide of the hole in the shell; wherein, the first-stage diffusion hole, the chamfered transition area, the groove of the valve sleeve and the inlet chamfer and the secondary diffusion hole of the valve seat together form a transition cavity Q.

[0010] Further preferably, the diameter of the secondary diffusion hole of the valve seat is smaller than the diameter of the first diffusion hole of the valve sleeve.

[0011] Further preferably, the diameter of the boss surface of the valve seat is larger than the outer diameter of the second sealing ring band of the valve sleeve.

[0012] Further 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.

[0013] Further preferably, the outer diameter of the valve seat is the same as the major diameter of the valve sleeve.

[0014] More preferably,

[0015] The inner diameter and outer diameter of the annular groove are adjustable to distribute the sealing pressure ratio acting on the first sealing ring band and the second sealing ring band.

[0016] The present invention also discloses an injector, characterized in that it comprises: a housing, a valve screw, a control plunger, a sealing ball and the above-mentioned split control valve; wherein: the small diameter of the valve sleeve is placed in the pressure storage chamber of the housing, and the large diameter is matched with the guide hole in 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 tightly against the inner end surface of the housing; the control plunger and the guide hole and the empty knife hole form a control chamber; the sealing ball and the sealing cone surface constitute a ball valve sealing pair.

[0017] Further preferably, the length of the first-stage diffusion hole is greater than its diameter, so as to reduce the fuel flow rate and suppress local backflow at the oil outlet.

[0018] Further 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.

[0019] Further preferably, the diameter of the oil return 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.

[0020] Advantages and technical effects of the present invention: The split control valve achieves the following technical effects by optimizing the oil return flow channel structure:

[0021] The transition cavity Q design reduces the flow velocity in the mainstream area, weakens the local backflow at the oil outlet, suppresses the triggering conditions of cavitation, and keeps the cavitation generation area away from the sealing seat surface, thereby extending the service life of the injector.

[0022] The two-stage sealing ring and ring groove structure improves the reliability of high-pressure sealing and has a wider adaptability to oil products;

[0023] The split structure reduces the difficulty of machining complex oil channels, allows for partial parts replacement, and reduces maintenance costs.

[0024] The oil return transition hole cooperates with the tapered diffusion hole to reduce the impact of pressure fluctuations on the injection pattern and improve injection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A fuel injector for implementing the split control valve of this application

[0026] Figure 2 The transition cavity structure implemented for this application;

[0027] Figure 3 Valve seat implemented for this application;

[0028] Figure 4 A valve sleeve implemented for this application;

[0029] Figure 5 This is a schematic diagram of the valve sleeve sealing surface structure implemented in this application.

[0030] In the figure: 1. Control plunger; 2. Valve sleeve; 2a. Guide hole; 2b. Hole hole; 2c. Oil return transition hole; 2d. Oil outlet throttling hole; 2e. First-stage diffusion hole; 2f. Chamfered transition zone; 2g. Oil inlet hole; 20. Valve sleeve minor diameter; 21. Valve sleeve major diameter; 23. Hole structure; 24. Boss; 25. First sealing ring band; 26. Second sealing ring band; 27. Ring groove; 271. Inner diameter of ring groove; 272. Outer diameter of ring groove; 28. Groove; 3. Valve seat; 3a. Oil outlet hole; 3b. Transition chamfer; 3c. Second-stage diffusion hole; 3d. Inlet chamfer; 30. Sealing cone surface; 31. Boss surface; 32. Outer diameter; 4. Sealing ball; 5. Housing; 50. Pressure storage chamber; 6. Valve screw DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] The present invention discloses a split control valve and its fuel injector, and the embodiments thereof are described as follows in combination with the structural features and technical effects:

[0033] Split control valve embodiment:

[0034] The split control valve consists of a valve sleeve 2 and a valve seat 3, forming an upper and lower split structure. The core innovation lies in solving the cavitation problem through flow channel optimization and split sealing design.

[0035] Valve sleeve 2 structure and flow channel design: Valve sleeve 2 adopts a two-stage outer diameter structure: the lower end small diameter 20 is placed in the high-pressure accumulator chamber 50 of the housing 5, and the upper end large diameter 21 cooperates with the guide hole in the housing 5 to ensure the coaxiality of the control plunger 1 movement; a hollow knife structure 23 is set at the intersection of the large and small diameters to eliminate the stress concentration of the shoulder. The end face of the large diameter 21 is equipped with a high-pressure sealing structure, which is composed of the first sealing ring 25, the ring groove 27, and the second sealing ring 26 from the inside to the outside. The area of ​​the first sealing ring 25 is ≤12mm 2 The inner side of the ring groove 27 is provided with a groove 28 with a diameter of ≤φ3.5mm. The ring groove 27 is sized by adjusting the inner diameter 271 and the outer diameter 272 to achieve a reasonable distribution of the sealing pressure between the first sealing ring band 25 and the second sealing ring band 26, thereby improving the sealing reliability under high pressure environment.

[0036] A flow channel is provided axially throughout: a guide hole 2a cooperates with the control plunger 1 to ensure smooth movement; a hollow bore 2b forms a control chamber with the control plunger 1, dynamically adjusting the injection pattern. The return oil transition hole 2c has a larger diameter than the outlet orifice 2d, reducing its sensitivity to pressure fluctuations. A first-stage diffuser 2e, longer than its diameter, is located behind the outlet orifice 2d. This reduces flow velocity in the mainstream, improves flow uniformity, and mitigates localized backflow at the outlet orifice. One end of the first-stage diffuser 2e connects to the outlet orifice 2d via a chamfered transition zone 2f, reducing fuel turbulence; the other end connects to a groove 28, directing airflow away from the sealing surface. An oil inlet 2g is provided on the side of the minor diameter 20. This, in combination with the diameter of the control plunger 1 and the diameter of the outlet orifice 2d, determines the dynamic pressure in the control chamber and controls the opening and closing of the needle valve.

[0037] Valve seat 3 structure and flow path design: A sealing cone 30 is located within the top volume chamber of the valve seat 3, forming a ball valve sealing pair with the sealing ball 4. When the sealing ball 4 contacts the sealing cone 30, a seal is achieved; when it disengages, oil injection is initiated. An oil outlet 3a is located at the lower end of the sealing cone 30, with a transition chamfer 3b between the oil outlet 3a and the sealing cone 30. A secondary diffuser 3c is located below the oil outlet 3a. The diameter of the secondary diffuser is smaller than the diameter of the first diffuser in the valve sleeve 2, forming a tapered structure that distances cavitation from the sealing cone 30. A boss 31 is located at the bottom end of the valve seat 3, with an inlet chamfer 3d at its intersection with the secondary diffuser 3c. The boss's diameter 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 aligns with the central hole in the housing 5 and is the same diameter as the major diameter 21 of the valve sleeve 2, further enhancing coaxiality.

[0038] Transition chamber Q structure and function: Transition chamber Q is composed of the first-stage diffuser 2e, chamfered transition zone 2f, groove 28, inlet chamfer 3d of valve seat 3, and secondary diffuser 3c of valve sleeve 2. This structure reduces cavitation by extending the diffuser hole length and optimizing the chamfer transition, suppressing cavitation triggering conditions. It also allows for partial component replacement, reducing maintenance costs.

[0039] Injector Example: An injector comprises a housing 5, a valve screw 6, a control plunger 1, a sealing ball 4, and the aforementioned split control valve. The valve sleeve 2, with its small diameter 20 positioned within the housing's pressure accumulator chamber 50, has its large diameter 21 guided by the central bore of the housing 5. The tightening force of the valve screw 6 acts on the boss surface 31 of the valve seat 3, which is then transmitted to the shoulder surface 29 of the valve sleeve 2, causing it to press against the inner end face of the housing 5, achieving a high-pressure seal. The control plunger 1, the guide hole 2a, and the hollow knife hole 2b of the valve sleeve 2 form a control chamber. The sealing ball 4 and the sealing cone 30 of the valve seat 3 form a ball valve sealing pair, which together control the opening and closing of the injector.

[0040] How it works

[0041] During fuel injector operation, 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 the sealing cone 30 of the valve seat 3, the high-pressure fuel enters the control chamber through the oil inlet 2g and returns through the oil outlet throttle 2d, the first-stage diffuser 2e, the transition chamber Q, and the second-stage diffuser 3c, creating a dynamic pressure balance. At this point, the needle valve opens, and fuel is injected into the combustion chamber. By optimizing the flow path structure (such as tapered orifices and long diffusers), local flow velocity and pressure fluctuations are reduced, cavitation is suppressed, and injector life is extended.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A split control valve, characterized in that: The valve sleeve (2) comprises an upper and lower split structure consisting of a valve sleeve (2) and a valve seat (3); the valve sleeve (2) comprises a two-stage outer diameter structure with a small diameter (20) at the lower end and a large diameter (21) at the upper end, and a hollow knife structure (23) is provided at the intersection of the large and small diameters; The high-pressure sealing structure of the large-diameter (21) end face is provided with a first sealing ring band (25), a ring groove (27), and a second sealing ring band (26) in sequence from the inside to the outside. The area of ​​the first sealing ring band (25) is ≤12mm. 2 , a groove (28) is provided on the inner side thereof and the diameter is ≤φ3.5mm; 9 A guide hole (2a), an idle knife hole (2b), an oil return transition hole (2c), an oil outlet throttling hole (2d), and a first-stage diffusion hole (2e) are arranged through the axial direction, wherein one end of the first-stage diffusion hole (2e) is connected to the oil outlet throttling hole (2d) via a chamfered transition area (2f), and the other end is connected to the groove (28); An oil inlet hole (2g) is provided on the side of the small diameter (20); The valve seat (3) comprises: a sealing cone surface (30) in the top volume cavity, a transition chamfer (3b), an oil outlet hole (3a) and a secondary diffusion hole (3c); An inlet chamfer (3d) is provided at the junction of the bottom end boss surface (31) and the secondary diffusion hole (3c); The outer diameter (32) is in guiding cooperation with the hole in the housing (5); The first-stage diffusion hole (2e), chamfered transition area (2f), groove (28) of the valve sleeve (2) and the inlet chamfer (3d) and second-stage diffusion hole (3c) of the valve seat (3) together form a transition chamber (Q).

2. The split control valve according to claim 1, characterized in that: The diameter of the secondary diffusion hole of the valve seat (3) is smaller than the diameter of the first diffusion 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 larger 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 the outer diameter (272) of the annular groove (27) are adjustable in size to distribute the sealing pressure ratio acting on the first sealing ring band (25) and the second sealing ring band (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 the split control valve according to any one of claims 1 to 6; Wherein: the small diameter (20) of the valve sleeve (2) is placed in the pressure storage chamber (50) of the housing, and the large diameter (21) is guided and matched with the hole in 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 surface of the shell (5); the control plunger (1) and the guide hole (2a) and the empty knife hole (2b) form a control chamber; the sealing ball (4) and the sealing cone surface (30) constitute a ball valve sealing pair.

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

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

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

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