Built-in common rail oil injector of pressure accumulation cavity type electromagnetic valve

Abstract

The invention provides a common-rail oil injector with a built-in pressure storage cavity type electromagnetic valve. The common-rail oil injector is characterized by comprising an oil injector body, and a pore plate and a middle body are arranged between a valve body of a needle valve and the oil injector body; a valve cavity of the needle valve is communicated with a pressure storage cavity in the oil injector body through a needle valve channel, a pore plate channel and an intermediate channel in sequence; a control cavity is formed in the lower end of the pore plate, an electromagnetic valve is arranged at the end, close to the middle body, of the oil sprayer body, a mandrel is welded to the lower end of an armature of the electromagnetic valve, a matching pore channel matched with the mandrel is formed in the middle body, and a sealing face matched with the upper side wall of the oil passing groove is arranged at the end, facing the electromagnetic valve, of the matching pore channel. A transition cavity is arranged at the joint of the pore plate channel and the intermediate channel, the control cavity is communicated with the transition cavity through an oil inlet cavity, and the matching pore channel is communicated with the transition cavity through an oil return cavity. According to the invention, a built-in electromagnetic valve scheme is adopted, so that electromagnetic interference can be effectively reduced, and the injection precision and the injection control capability are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of common rail fuel injection systems, and in particular relates to a common rail fuel injector with a built-in pressure accumulator solenoid valve. Background Art

[0002] The traditional common rail fuel injector adopts the structure of a long tappet with a solenoid valve on top. The main problems are: (1) The solenoid valve is installed on the top of the injector, and the terminal is exposed to the outside, which is easy to generate electromagnetic signal interference; (2) The number of moving parts is large and the mass is large, which reduces the needle valve response and restricts the flexibility of multiple injection control; (3) The injection pressure fluctuates greatly and the stability of multiple injections is poor. Fig.10 The figure shows the control principle diagram of the common rail injector with a long push rod on the upper part of the solenoid valve. After the solenoid valve is energized, a certain electromagnetic force is generated to suck up the armature plate, and the armature drives the valve core to move upward, so that the ball valve is opened, the pressure in the control chamber is reduced, so that the control piston drives the push rod to lift the needle valve, and the injector starts to spray oil. In the prior art, since the solenoid valve is far away from the control needle valve, the electromagnetic force needs to be transmitted through the control push rod, which reduces the injection response speed and injection control accuracy of the injector. Therefore, it is necessary to improve the existing common rail injector. Summary of the invention

[0003] In view of this, the invention aims to overcome the defects in the prior art and proposes a common rail injector with a pressure accumulator type solenoid valve built in.

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

[0005] A pressure accumulator type solenoid valve built-in common rail fuel injector comprises a fuel injector body, an oil inlet joint is installed at the upper end of the fuel injector body, a needle valve is installed at the lower end, and the needle valve is fixed to the fuel injector body through a nozzle cap; the needle valve comprises a valve body and a valve core, an orifice plate and an intermediate body are arranged between the valve body and the fuel injector body, and the orifice plate is close to one side of the needle valve; the valve cavity of the needle valve is connected with the pressure accumulator cavity in the fuel injector body through the needle valve channel, the orifice plate channel and the intermediate body channel in sequence;

[0006] A control chamber is provided at the lower end of the orifice plate corresponding to the valve chamber position, a needle valve spring is provided in the control chamber, and the top end of the valve core is against the needle valve spring; a solenoid valve is provided at one end of the injector body close to the intermediate body, the lead wire of the solenoid valve is led outward through the injector body, a core shaft is welded at the lower end of the armature of the solenoid valve, an oil groove is provided in the middle of the outer wall of the core shaft, a matching channel matching with the core shaft is provided on the intermediate body, and a sealing surface matching with the upper side wall of the oil groove is provided at one end of the matching channel facing the solenoid valve;

[0007] A transition chamber is provided at the junction of the orifice channel and the intermediate body channel, the control chamber is connected with the transition chamber through the oil inlet chamber, the matching channel is connected with the transition chamber through the oil return chamber, and the diameter of the oil inlet chamber is larger than the diameter of the oil return chamber. The oil inlet chamber is close to one end of the intermediate body and is provided with an oil inlet hole connected with the transition chamber and a communicating hole connected with the oil return chamber; when the solenoid valve is powered off, the oil return chamber is connected with the oil groove of the core shaft, and when the solenoid valve is powered on, the oil groove of the core shaft is connected with the connecting channel of the intermediate body.

[0008] Furthermore, the upper side wall of the oil groove is a conical surface, and the sealing surface is a sealing conical surface matching the conical surface.

[0009] Furthermore, a positioning column is provided at the upper end of the valve core, the diameter of the positioning column is smaller than the diameter of the valve core, and the needle valve spring is sleeved on the positioning column, with its lower end abutting against the valve core and its upper end abutting against the orifice plate.

[0010] Furthermore, the oil nozzle cap is threadedly connected to the fuel injector body.

[0011] Furthermore, a sealing ring is provided between the fuel injector body and the fuel nozzle cap.

[0012] Furthermore, the oil inlet chamber and the oil return chamber are both arranged obliquely relative to the axis of the injector body.

[0013] Furthermore, the outer wall of the core shaft is provided with at least one annular groove at positions corresponding to the upper and lower sides of the oil groove.

[0014] Furthermore, the valve core lift of the needle valve is 0.5±0.01 mm.

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

[0016] The fuel injector provided by the invention adopts a built-in solenoid valve solution to reduce the size and weight of moving parts and optimize the hydraulic structure, which can effectively reduce electromagnetic interference. At the same time, the fuel injector eliminates the transmission mechanism such as the control piston and shortens the needle valve length as much as possible. It can effectively reduce the motion mass of the hydraulic servo mechanism such as the control piston, and shorten the oil channel length between the control chamber and the oil nozzle, which is beneficial to improve the injection control and hydraulic response speed. By adding a built-in pressure accumulator chamber to reduce the pressure fluctuation caused by large oil injection, the injection accuracy and the control ability of the injection are improved. 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 1 A schematic diagram of the structure created by the present invention;

[0019] Figure 2A schematic diagram of the lower structure of the fuel injector is created for the present invention;

[0020] Figure 3 A schematic diagram of the injector orifice plate and intermediate body portion is created for the present invention;

[0021] Figure 4 A schematic diagram of the matching relationship between the mesoporous plate and the intermediate body is created for the present invention;

[0022] Figure 5 A schematic diagram of the matching relationship between the intermediate and the mandrel is created in the present invention;

[0023] Figure 6 The invention creates a solenoid valve that is energized to Figure 5 Schematic diagram after the core axis moves upward;

[0024] Figure 7 A schematic diagram of the structure of the central shaft of the present invention;

[0025] Figure 8 It is a schematic diagram of the structure of the intermediate in the invention;

[0026] Fig. 9 A schematic diagram of the structure of the mesoporous plate created by the present invention;

[0027] Fig.10 It is a schematic diagram of a common rail injector with a long push rod and an upper solenoid valve in the prior art. DETAILED DESCRIPTION

[0028] 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.

[0029] 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. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0030] 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.

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0032] A pressure accumulator type solenoid valve with built-in common rail injector, such as Figures 1 to 9 As shown, it includes an injector body 1, an oil inlet connector 2 is installed at the upper end of the injector body, and a needle valve 3 is installed at the lower end. The needle valve is fixed to the injector body through an oil nozzle cap 4. In an optional embodiment, the oil inlet connector is threadedly connected to the injector body, and a rigid seal is achieved through a threaded pair to alleviate the pressure drop caused by rapid injection and ensure the injection pressure and injection rate during the injection process. The needle valve includes a valve body 5 and a valve core 6. An orifice plate 7 and an intermediate body 8 are provided between the valve body and the injector body, and the orifice plate is close to one side of the needle valve; the valve cavity 23 of the needle valve is connected to the pressure storage chamber 16 in the injector body through the needle valve channel 9, the orifice channel 10 and the intermediate body channel 11 in sequence. As an example, the intermediate body channel is connected to the pressure storage chamber in the injector body through the oil supply channel 34 provided on the injector body.

[0033] A control chamber 12 is provided at the lower end of the orifice plate corresponding to the valve chamber position, and a needle valve spring 13 is provided in the control chamber, and the top of the valve core is against the needle valve spring; a solenoid valve 14 is provided at one end of the injector body close to the intermediate body, and the lead wire 15 of the solenoid valve is led outward through the injector body, and the threading hole of the lead wire is arranged to avoid the pressure storage chamber in the injector body. A core shaft 17 is welded at the lower end of the armature of the solenoid valve, and an oil groove 18 is provided in the middle of the outer wall of the core shaft. A matching channel 19 matching with the core shaft is provided on the intermediate body, and a sealing surface 20 matching with the upper side wall of the oil groove is provided at one end of the matching channel facing the solenoid valve; a fuel injection nozzle 21 is provided at the lower end of the valve body. When the solenoid valve is closed, the lower end of the valve core seals the fuel injection nozzle. When the solenoid valve is opened, the valve core moves up, and fuel injection is realized at the fuel injection nozzle.

[0034] A transition chamber 22 is provided at the junction of the orifice plate channel and the intermediate body channel, the control chamber is connected to the transition chamber through the oil inlet chamber 24, the matching channel is connected to the transition chamber through the oil return chamber 25, the oil inlet chamber is close to one end of the intermediate body, and is provided with an oil inlet hole 26 connected to the transition chamber, and a connecting hole 27 connected to the oil return chamber; when the solenoid valve is powered off, the oil return chamber is connected to the oil groove of the core shaft, and when the solenoid valve is powered on, the oil groove of the core shaft is connected to the connecting channel 28 of the intermediate body, and the diameter of the oil inlet chamber is larger than the diameter of the oil return chamber. In an optional embodiment, a concave platform 29 is provided at the lower end of the matching channel, and oil is retained at the concave platform. When the solenoid valve is closed, it can play a buffering role on the solenoid valve and reduce the vibration of the injector to a certain extent.

[0035] As an example, the upper side wall of the oil groove is a conical surface 30, and the sealing surface is a sealing conical surface matching it. A positioning column 31 is provided at the upper end of the valve core, and the diameter of the positioning column is smaller than the diameter of the valve core. The needle valve spring is sleeved on the positioning column, and its lower end abuts against the valve core and the upper end abuts against the orifice plate. The oil nozzle cap is threadedly connected to the injector body. A sealing ring 32 is provided between the injector body and the oil nozzle cap. The oil inlet chamber and the oil return chamber are both arranged obliquely relative to the axis of the injector body. The outer wall of the core shaft is provided with at least one annular groove 33 at the position corresponding to both sides of the oil groove. As an example, the valve core lift of the needle valve is 0.5±0.01mm.

[0036] Working principle:

[0037] When the solenoid valve is powered on, it generates electromagnetic force to suck up the armature. Since the armature and the mandrel are connected together by laser welding, the mandrel moves upward, and the high-pressure oil flows out from the conical surface gap between the intermediate body and the mandrel. Since the oil leakage is greater than the oil inlet, the pressure in the control chamber is rapidly reduced, and the pressure on the upper end face of the valve core is reduced, so the valve core is quickly lifted, so that the high-pressure fuel is sprayed out from the nozzle of the injection nozzle. After the solenoid valve is powered off, the electromagnetic force disappears, and the mandrel moves downward under the action of the liquid pressure, forming a seal with the intermediate body again, and the fuel pressure in the control chamber rises rapidly through the flow supplement of the orifice plate oil inlet chamber, and moves downward under the joint action of the upper end liquid pressure and the needle valve spring, and the valve core is seated, and the pressure at both ends is balanced again, thereby closing the injector and completing a fuel injection process.

[0038] The common rail fuel injector provided by the invention adopts a built-in solenoid valve, which is arranged inside the fuel injector and is sunk above the needle valve to reduce the inertial mass of the moving parts and shorten the oil path length from the control chamber to the nozzle, thereby improving the injection control response speed, meeting the technical requirements of multi-cycle fuel injection stability of the fuel injector, and effectively reducing electromagnetic interference. At the same time, the fuel injector cancels the push rod, so that the control chamber is no longer connected to the low-pressure return oil path, and the fuel pressure at the core shaft changes from the low-pressure return oil pressure to the high-pressure supply pressure. There is no high-low pressure difference between the pairs, thereby eliminating the static leakage between the needle valve pairs, improving the injection efficiency of the fuel injector, and reducing the workload of the high-pressure supply pump.

[0039] 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 pressure accumulator type solenoid valve with a built-in common rail injector, characterized in that: It comprises a fuel injector body, an oil inlet joint is installed at the upper end of the fuel injector body, a needle valve is installed at the lower end, and the needle valve is fixed to the fuel injector body through a nozzle cap; the needle valve comprises a valve body and a valve core, an orifice plate and an intermediate body are arranged between the valve body and the fuel injector body, and the orifice plate is close to one side of the needle valve; the valve cavity of the needle valve is connected with the pressure storage cavity in the fuel injector body through the needle valve channel, the orifice plate channel and the intermediate body channel in sequence; A control chamber is provided at the lower end of the orifice plate corresponding to the valve chamber position, a needle valve spring is provided in the control chamber, and the top end of the valve core is against the needle valve spring; an electromagnetic valve is provided at one end of the injector body close to the intermediate body, and the lead of the electromagnetic valve is led outward through the injector body, a core shaft is welded at the lower end of the armature of the electromagnetic valve, an oil groove is provided in the middle of the outer wall of the core shaft, a matching channel matching with the core shaft is provided on the intermediate body, and a sealing surface matching with the upper side wall of the oil groove is provided at one end of the matching channel facing the electromagnetic valve; A transition chamber is provided at the junction of the orifice channel and the intermediate body channel, the control chamber is connected with the transition chamber through the oil inlet chamber, the matching channel is connected with the transition chamber through the oil return chamber, and the diameter of the oil inlet chamber is larger than the diameter of the oil return chamber. The oil inlet chamber is close to one end of the intermediate body and is provided with an oil inlet hole connected with the transition chamber and a communicating hole connected with the oil return chamber; when the solenoid valve is powered off, the oil return chamber is connected with the oil groove of the core shaft, and when the solenoid valve is powered on, the oil groove of the core shaft is connected with the connecting channel of the intermediate body.

2. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: The upper side wall of the oil groove is a conical surface, and the sealing surface is a sealing conical surface matching the conical surface.

3. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: A positioning column is arranged at the upper end of the valve core, the diameter of which is smaller than the diameter of the valve core, and the needle valve spring is sleeved on the positioning column, with the lower end of the spring abutting against the valve core and the upper end abutting against the orifice plate.

4. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: The nozzle cap is threadedly connected to the injector body.

5. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: A sealing ring is provided between the injector body and the nozzle cap.

6. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: The oil inlet chamber and the oil return chamber are both arranged obliquely relative to the axis of the injector body.

7. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: The outer wall of the core shaft is respectively provided with at least one annular groove on the upper and lower sides corresponding to the oil groove.

8. The pressure accumulator type solenoid valve built-in common rail injector according to claim 1, characterized in that: The valve core lift of the needle valve is 0.5±0.01mm.

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