Split type ultrahigh pressure common rail oil injector control valve

Abstract

The split type ultrahigh pressure common rail oil injector control valve comprises a valve body, a valve body function hole is formed in the upper end of the valve body, a control valve rod matching hole is formed in the lower end of the valve body, an oil outlet pressing block is installed in the control valve rod matching hole, and an oil outlet pressing block function hole matched with the valve body function hole is formed in the oil outlet pressing block; the valve body function hole comprises a conical hole section at the upper end and a valve body upper cylindrical hole section at the lower end, and a drainage hole section is arranged between the conical hole section at the upper end and the valve body upper cylindrical hole section at the lower end; the oil outlet pressing block functional hole comprises an oil outlet pressing block upper cylindrical hole section, an oil outlet pressing block upper taper hole section and a lower cylindrical hole section which are sequentially arranged from top to bottom. The control valve is of a split structure, and the precise control function of the circulating fuel injection quantity of the fuel injector can be achieved. The oil outlet pressing block is provided with a section of conical gradually-expanded fuel oil channel, the cavitation position can be effectively transferred, and cavitation is prevented from being generated at the contact position of a sealing steel ball and a sealing seat face in the control valve assembly.

Description

Technical Field

[0001] The invention belongs to the technical field of common rail injectors, and in particular relates to a split type ultra-high pressure common rail injector control valve. Background Art

[0002] The common rail injector control valve is a key structure in the injector and is the component that truly controls fuel injection. It controls the opening and closing of the needle valve by adjusting the fuel pressure in the control chamber to change the cross-sectional force on the needle valve. The control chamber is adjusted by opening and closing the return oil circuit to adjust the fuel pressure in the control chamber. During this process, the oil inlet circuit on the control chamber is always in a connected state. However, under high pressure difference, cavitation is prone to occur in the variable cross-sectional area of ​​the control valve, and there is a local blocked flow state. On the one hand, it leads to the formation of an unstable flow field in the control chamber, making it difficult to ensure the accuracy of injection control. On the other hand, cavitation and the collision of the ball valve lead to cavitation on the sealing surface, which makes the injector seal fail and has a significant impact on the injection characteristics and stability. With the development of combustion theory, ultra-high pressure injection has been proven to be an effective means to improve the economy and emissions of diesel engines under various operating conditions. However, with the continuous increase in injection pressure (≥200MPa), such as Figure 3 As shown, the control valve structure in the prior art can no longer withstand the impact of high pressure. During the operation of the injector, the sealing seat surface is prone to cavitation and pitting, which accelerates the failure of the sealing seat surface and further reduces the reliability of the system operation. Summary of the invention

[0003] In view of this, the present invention aims to overcome the defects in the prior art and proposes a split type ultra-high pressure common rail injector control valve.

[0004] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0005] A split type ultra-high pressure common rail injector control valve comprises a valve body, wherein the upper end of the valve body is provided with a valve body function hole, the lower end is provided with a control valve stem matching hole, an oil outlet pressure block is installed in the control valve stem matching hole, the oil outlet pressure block is provided with an oil outlet pressure block function hole matching the valve body function hole, and the valve body function hole and the oil outlet pressure block function hole are coaxially arranged;

[0006] The valve body functional hole comprises a conical hole section at the upper end and a valve body upper cylindrical hole section at the lower end, a drainage hole section is provided between the conical hole section at the upper end and the valve body upper cylindrical hole section at the lower end, the diameter of the valve body upper cylindrical hole section is smaller than the valve body upper cylindrical hole section, and a sealing seat surface is formed at the junction of the conical hole section and the drainage hole section;

[0007] The functional hole of the oil outlet pressure block comprises an upper cylindrical hole section of the oil outlet pressure block, an upper conical hole section of the oil outlet pressure block, a lower cylindrical hole section of the oil outlet pressure block and an expanded diameter section which are arranged in sequence from top to bottom. The inner diameter of the lower cylindrical hole section of the oil outlet pressure block is smaller than the inner diameter of the upper cylindrical hole section of the oil outlet pressure block, the inner diameter of the expanded diameter section is larger than the inner diameter of the lower cylindrical hole section of the oil outlet pressure block, and a step is formed between the expanded diameter section and the lower cylindrical hole section of the oil outlet pressure block;

[0008] A first raised platform is provided at the bottom of the control valve stem matching hole, and the surface of the first raised platform is in contact with the upper end surface of the oil outlet pressure block, so that the cylindrical hole section on the valve body is connected with the cylindrical hole section on the oil outlet pressure block; a second raised platform is provided at the lower end of the oil outlet pressure block, and an annular groove is provided on the inner wall of the control valve stem matching hole corresponding to the position below the oil outlet pressure block, and an oil inlet throttling hole is provided at the position corresponding to the annular groove. In the height direction, the lower edge of the second raised platform is within the coverage range of the annular groove.

[0009] Furthermore, a third raised platform is provided on the outer wall of the valve body.

[0010] Furthermore, a sink is provided at one end of the oil inlet throttling hole facing the outer wall of the valve body.

[0011] Furthermore, the oil outlet pressure block and the matching hole of the control valve stem are interference fit.

[0012] Furthermore, a cone section is provided at the upper end of the oil outlet pressure block, so that the annular groove and the annular cavity extend to the periphery of the cone section.

[0013] Furthermore, a chamfered structure is provided at the outer end of the matching hole of the control valve stem.

[0014] Furthermore, the inner diameters of the cylindrical hole section on the valve body and the cylindrical hole section on the oil outlet pressure block are the same.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The split ultra-high pressure common rail injector control valve provided by the present invention has a conical and gradually expanding nozzle-type oil leakage channel designed on the return oil channel compared with the traditional "three-stage" control valve. The design of this structure, on the one hand, plays a flow amplification role, effectively improving the oil return efficiency of the injector, and on the other hand, inhibits the formation of cavitation in the return oil channel during the oil leakage operation of the injector, and blocks the cavitation collection formed at the return oil throttle hole and the sealing seat surface, thereby reducing the cavitation formation at the sealing seat surface of the injector control valve under ultra-high pressure, and greatly improving the sealing reliability of the injector control valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0018] Figure 1A schematic diagram of the structure created by the present invention;

[0019] Figure 2 A schematic diagram of the valve body portion of the present invention;

[0020] Figure 3 It is a schematic diagram of the oil outlet briquetting part of the invention;

[0021] Figure 4 It is a schematic diagram of the sealing seat surface part in the invention. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0024] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0025] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0026] A split type ultra-high pressure common rail injector control valve, such as Figures 1 to 4 As shown, it comprises a valve body 1, a valve body function hole 2 is provided at the upper end of the valve body, and a control valve stem matching hole 3 is provided at the lower end. 在 The control valve stem matching hole is installed with an oil pressure block 4 ，The oil outlet pressure block is provided with an oil outlet pressure block functional hole 5 matching the valve body functional hole, and the valve body functional hole is coaxially arranged with the oil outlet pressure block functional hole. The valve body functional hole includes a conical hole section 6 at the upper end and a valve body upper cylindrical hole section 7 at the lower end, and a drainage hole section 8 is provided between the conical hole section at the upper end and the valve body upper cylindrical hole section at the lower end. The diameter of the valve body upper cylindrical hole section is smaller than that of the valve body upper cylindrical hole section, and a sealing seat surface is formed at the junction of the conical hole section and the drainage hole section. As an example, the cone angle of the conical hole section is 125°±0.5°.

[0027] The functional hole of the oil outlet pressure block includes an upper cylindrical hole section 9 of the oil outlet pressure block, an upper conical hole section 10 of the oil outlet pressure block, a lower cylindrical hole section 11 of the oil outlet pressure block and an expanded diameter section 22 arranged from top to bottom. The inner diameter of the lower cylindrical hole section of the oil outlet pressure block is smaller than the inner diameter of the upper cylindrical hole section of the oil outlet pressure block, and the inner diameter of the expanded diameter section is larger than the inner diameter of the lower cylindrical hole section of the oil outlet pressure block. A step 23 is formed between the expanded diameter section and the lower cylindrical hole section of the oil outlet pressure block. The upper end (large opening end) of the upper conical hole section of the oil outlet pressure block is connected with the upper cylindrical hole section of the oil outlet pressure block, and the lower end (small opening end) of the upper conical hole of the oil outlet pressure block is connected with the lower cylindrical hole section of the oil outlet pressure block.

[0028] The inner diameter of the upper cylindrical hole section of the oil outlet pressure block is the same as the inner diameter of the upper conical hole section at the maximum diameter, and the inner diameter of the lower cylindrical hole section of the oil outlet pressure block is the same as the inner diameter of the upper conical hole section at the minimum diameter, that is, the oil passage on the oil outlet pressure block (the functional hole of the oil outlet pressure block) is first reduced and then increased. On the one hand, it plays a role in flow amplification, similar to the "Venturi effect", and effectively improves the oil return capacity of the control cavity without increasing the aperture of the fuel return hole. On the other hand, this structure can effectively inhibit the formation of cavitation in the oil return oil channel, and at the same time block the cavitation collection formed at the oil return throttling hole, valve body and sealing ball.

[0029] Specifically, the design of the tapered section on the oil outlet pressure block effectively accelerates the flow of fuel and causes cavitation, that is, the cavitation position is cleverly moved downward. Since there is a longer cylindrical hole behind the tapered hole (the cylindrical hole section on the valve body and the cylindrical hole section on the oil outlet pressure block), the cavitation will not be transmitted to the sealing steel ball (sealing seat surface) position, which can avoid the formation of cavitation on the sealing seat surface and greatly improve the sealing reliability of the control valve.

[0030] A first raised platform 12 is provided at the bottom of the control valve stem matching hole, and the surface of the first raised platform is fitted with the upper end surface of the oil outlet pressure block, so that the cylindrical hole section on the valve body is connected with the cylindrical hole section on the oil outlet pressure block. Preferably, the inner diameters of the cylindrical hole section on the valve body and the cylindrical hole section on the oil outlet pressure block are the same. A second raised platform 14 is provided at the lower end of the oil outlet pressure block, and an annular groove 15 is provided on the inner wall of the control valve stem matching hole corresponding to the position below the oil outlet pressure block, and an oil inlet throttling hole 16 is provided at the corresponding position of the annular groove. In the height direction, the lower edge of the second raised platform is within the coverage range of the annular groove. When the injector is working, the annular groove position serves as a control chamber. A third raised platform 17 is provided on the outer wall of the valve body, which is very convenient for positioning during installation. A sink 18 is provided at one end of the oil inlet throttling hole facing the outer wall of the valve body. The oil outlet pressure block and the control valve stem matching hole are interference fit. A chamfered structure 20 is provided at the outer end of the control valve stem matching hole to facilitate the installation of the oil outlet pressure block.

[0031] As an example, the diameter of the oil inlet throttling hole is 0.22±0.005mm, and the diameter of the drainage hole section is 0.46±0.01mm. The diameter of the control valve stem matching hole is 4.3±0.01mm. In an optional embodiment, a buffer ring cavity 13 is formed between the oil outlet pressure block and the valve body. In a further improved scheme, a cone section 19 is provided at the upper end of the outer wall of the oil outlet pressure block, so that the buffer ring cavity extends to the periphery of the cone section (the position corresponding to the cone section), which not only facilitates the smooth installation of the oil outlet pressure block into the control valve stem matching hole, but also enables a larger buffer ring cavity volume to be obtained.

[0032] In the above-mentioned structural design scheme with a buffer ring cavity, a non-sealed state is allowed between the oil outlet pressure block and the inner wall of the control valve stem matching hole or / and between the first raised platform surface and the oil outlet pressure block. Moreover, the oil outlet pressure block and the inner wall of the control valve stem matching hole or / and between the first raised platform surface and the oil outlet pressure block can even be deliberately designed to be in a non-sealed state, thereby reducing the processing difficulty of the valve body and the oil outlet pressure block, and the assembly (valve body with the oil outlet pressure block installed) has a higher yield rate.

[0033] Since the groove ring cavity serves as a transition cavity for oil inlet and outlet, it plays a role of "energy storage" in the process of increasing the oil pressure in the control cavity, and can also play a role of "energy release" at the moment when the oil pressure in the control cavity decreases. Therefore, it can better reduce the impact (or vibration) during the operation of the injector, and is also beneficial to prevent cavitation and pitting at the sealing seat surface.

[0034] The control valve created by the present invention adopts a split structure, and the oil outlet pressure block is installed into the control valve body by interference fitting. During the operation of the control valve, the high-pressure fuel in the control chamber will exert a force on the oil outlet pressure block, so that the valve body and the oil outlet pressure block always maintain a close fit state. The stability of the combined control valve structure is guaranteed, and the precise control function of the cyclic injection amount of the injector can be realized. The oil outlet pressure block is designed with a conical and gradually expanding fuel channel. The design of this structure effectively transfers the position of cavitation, which can avoid cavitation at the contact position between the sealing steel ball and the sealing seat surface in the control valve assembly, improve the reliability of the seal between the sealing ball and the valve body, and make it possible for the injector to achieve ultra-high pressure injection. However, the control valve in the prior art cannot work stably in ultra-high pressure conditions for a long time.

[0035] 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, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A split type ultra-high pressure common rail injector control valve, characterized in that: It comprises a valve body, wherein the upper end of the valve body is provided with a valve body function hole, the lower end is provided with a control valve stem matching hole, an oil outlet pressure block is installed in the control valve stem matching hole, the oil outlet pressure block is provided with an oil outlet pressure block function hole matching the valve body function hole, and the valve body function hole and the oil outlet pressure block function hole are coaxially arranged; The valve body functional hole comprises a conical hole section at the upper end and a valve body upper cylindrical hole section at the lower end, a drainage hole section is provided between the conical hole section at the upper end and the valve body upper cylindrical hole section at the lower end, the diameter of the valve body upper cylindrical hole section is smaller than the valve body upper cylindrical hole section, and a sealing seat surface is formed at the junction of the conical hole section and the drainage hole section; The functional hole of the oil outlet pressure block comprises an upper cylindrical hole section of the oil outlet pressure block, an upper conical hole section of the oil outlet pressure block, a lower cylindrical hole section of the oil outlet pressure block and an expanded diameter section which are arranged in sequence from top to bottom. The inner diameter of the lower cylindrical hole section of the oil outlet pressure block is smaller than the inner diameter of the upper cylindrical hole section of the oil outlet pressure block, the inner diameter of the expanded diameter section is larger than the inner diameter of the lower cylindrical hole section of the oil outlet pressure block, and a step is formed between the expanded diameter section and the lower cylindrical hole section of the oil outlet pressure block; A first raised platform is provided at the bottom of the control valve stem matching hole, and the surface of the first raised platform is in contact with the upper end surface of the oil outlet pressure block, so that the cylindrical hole section on the valve body is connected with the cylindrical hole section on the oil outlet pressure block; a second raised platform is provided at the lower end of the oil outlet pressure block, and an annular groove is provided on the inner wall of the control valve stem matching hole corresponding to the position below the oil outlet pressure block, and an oil inlet throttling hole is provided at the position corresponding to the annular groove. In the height direction, the lower edge of the second raised platform is within the coverage range of the annular groove.

2. A split type ultra-high pressure common rail injector control valve according to claim 1, characterized in that: The outer wall of the valve body is provided with a third protruding platform.

3. The split type ultra-high pressure common rail injector control valve according to claim 1, characterized in that: A sink is arranged at one end of the oil inlet throttling hole facing the outer wall of the valve body.

4. The split type ultra-high pressure common rail injector control valve according to claim 1, characterized in that: The oil outlet pressure block is interference fit with the matching hole of the control valve stem.

5. The split type ultra-high pressure common rail injector control valve according to claim 1, characterized in that: A cone section is provided at the upper end of the oil outlet pressure block, so that the annular groove and annular cavity extend to the periphery of the cone section.

6. The split type ultra-high pressure common rail injector control valve according to claim 1, characterized in that: The outer end of the matching hole of the control valve stem is provided with a chamfered structure.

7. The split type ultra-high pressure common rail injector control valve according to claim 1, characterized in that: The inner diameters of the cylindrical hole section on the valve body and the cylindrical hole section on the oil outlet pressure block are the same.

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