CN106762287B

CN106762287B - Resonant orifice plate type electric control oil injector with hydraulic feedback

Info

Publication number: CN106762287B
Application number: CN201710034974.5A
Authority: CN
Inventors: 范立云; 张孝勇; 袁志国; 刘友
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2017-01-18
Filing date: 2017-01-18
Publication date: 2023-03-21
Anticipated expiration: 2037-01-18
Also published as: CN106762287A

Abstract

The invention aims to provide a resonant orifice plate type electric control oil injector with hydraulic feedback, which comprises an oil injector head, an oil injector body, a flow limiting valve component, an electromagnetic valve component, a needle valve component and the like. The pressure storage cavity is arranged in the oil sprayer body and communicated with the main oil inlet hole and the flow limiting valve assembly, and stability of oil spraying processes of all cylinders is guaranteed when oil is sprayed with large pulse width. The flow-limiting valve component is arranged below the pressure accumulation cavity, so that abnormal continuous oil injection is avoided. The electromagnetic valve component is processed at the bottom of the oil sprayer body, and the valve rod is driven by electromagnetic force to move, so that the flexible oil spraying strategy and the oil spraying process with quick response and high control precision can be realized. The addition of the feedback oil circuit in the electromagnetic valve component slows down the opening of the needle valve and accelerates the seating of the needle valve. And two paths of oil inlets of a pore plate throttling hole and an annular side oil circuit in the needle valve assembly further accelerate the pressure building process of the control cavity and greatly improve the response speed of the needle valve in a seating mode.

Description

Resonant orifice plate type electric control oil injector with hydraulic feedback

Technical Field

The invention relates to an oil injection device of an engine, in particular to a high-pressure common rail oil injection device.

Background

High-speed solenoid valve injectors are beginning to be adopted by the market to adapt to the latest emission regulations. The electric control oil injector is characterized in that the electric signal output by the electric control unit is used for controlling the high-speed electromagnetic valve to realize a flexible oil injection rule. The oil sprayer adopting the high-speed electromagnetic valve has the advantages of quick system response, high control precision and capability of spraying for multiple times. However, there are also areas where improvements are needed for such electronically controlled fuel injectors: during the injection process, high-pressure fuel always flows through the fuel inlet and outlet orifices. The part of high-pressure fuel oil is pressurized by the oil pump, but does not work and directly returns to the oil tank, and the dynamic oil return amount is large, so that the energy loss is caused. Meanwhile, in order to reduce the emission of nitrogen oxides, the instantaneous injection rate of the injection process is required to be controlled, and the injection rate at the initial stage of injection is reduced. At the end of the injection event, the injector must be shut off quickly, i.e., the needle seating response is fast, to reduce the amount of particulate matter formed. Therefore, the requirement of the diesel engine emission on the oil injector is that the oil injection process can form an oil injection rate form with slow opening at the initial stage and fast closing at the end.

In addition, the accurate control of the multiple injection oil injection rule is the most advantage and key technology of the high-pressure common rail electronic control oil injection system of the diesel engine. In the multiple injection of the high-pressure common rail system, the water hammer pressure fluctuation caused by the injection directly influences the realization of the ideal oil injection rule of the multiple injection, thereby influencing the performance of the diesel engine.

Disclosure of Invention

The invention aims to provide a resonant orifice plate type electric control oil injector with hydraulic feedback, which can ensure small fuel pressure fluctuation during multiple injection, can realize micro-dynamic oil return, quick response of a needle valve and no static leakage function.

The purpose of the invention is realized by the following steps:

the invention relates to a resonant orifice plate type electric control oil injector with hydraulic feedback, which is characterized in that: the oil sprayer comprises an oil sprayer head, an oil sprayer body, a flow limiting valve assembly, a solenoid valve assembly, a needle valve assembly and a downlink high-pressure oil way, wherein the oil sprayer head is arranged above the oil sprayer body, a main oil inlet hole is formed in the oil sprayer head, a pressure storage cavity is formed in the oil sprayer body, the main oil inlet hole is communicated with the pressure storage cavity, the flow limiting valve assembly is arranged in the pressure storage cavity, the solenoid valve assembly and the needle valve assembly are sequentially arranged at the lower end of the oil sprayer body, a tightening cap is positioned outside the solenoid valve assembly and the needle valve assembly, and the upper end of the tightening cap is connected with the lower end of the oil sprayer body in a threaded connection mode;

the flow limiting valve assembly comprises a limiting spring seat, a flow limiting piston, a ball valve reset spring seat and a supporting control slider, wherein the limiting spring seat, the flow limiting piston and the ball valve reset spring seat are arranged from top to bottom;

the electromagnetic valve component comprises an electromagnet, a coil, an armature, a balance valve rod, a valve seat and an intermediate block, wherein the coil is wound on the electromagnet, an electromagnetic valve reset spring seat is arranged above the electromagnet, the armature is arranged below the electromagnet, an electromagnetic valve reset spring is arranged between the armature and the electromagnetic valve reset spring seat, the balance valve rod is positioned in the valve seat, the upper end part of the balance valve rod is fixedly connected with the armature, the intermediate block is arranged below the valve seat, a balance valve rod cavity is formed among the lower end part of the balance valve rod, the valve seat and the intermediate block, an oil return hole, an intermediate oil way, a lower oil inlet hole and a feedback oil way are arranged in the intermediate block, the intermediate oil way and the feedback oil way are respectively communicated with the balance valve rod cavity, and the oil return hole is communicated with or disconnected with the intermediate oil way and an oil tank under the control of the balance valve rod;

the needle valve assembly comprises a needle valve limiting sleeve, an orifice plate, a needle valve body and a nozzle, wherein the needle valve limiting sleeve is positioned in the nozzle, the orifice plate is positioned in the needle valve limiting sleeve, the upper part of the needle valve body is positioned in the needle valve limiting sleeve, the lower part of the needle valve body is positioned in the nozzle, a control cavity is formed between the orifice plate and the needle valve body, an orifice plate return spring is arranged in the control cavity, a bulge part is arranged in the middle of the needle valve body, the needle valve return spring is arranged between the bulge part and the needle valve limiting sleeve above the bulge part, a low pressure port and a high pressure port are respectively formed between the upper end surface of the orifice plate and a middle block, an orifice hole is arranged in the orifice plate and is respectively communicated with the low pressure port and the control cavity, a side oil circuit is formed between the orifice plate and the needle valve limiting sleeve outside the orifice plate, an oil containing groove is formed between the needle valve body and the nozzle, and the end part is provided with an orifice hole;

the middle oil way is communicated with the low-pressure port, the descending oil inlet hole is communicated with the high-pressure port, the upper end of the descending high-pressure oil way is communicated with the transition oil cavity and is communicated with the oil containing groove through the oil injector body, the valve seat, the middle block and the nozzle, and the descending oil inlet hole and the feedback oil way are respectively communicated with the descending high-pressure oil way.

The present invention may further comprise:

1. when the spray hole sprays oil, the fuel pressure of the transition oil cavity is reduced, the whole of the flow-limiting piston, the ball valve and the supporting control slide block moves downwards, the ball valve is not seated on the ball valve reset spring seat, and the flow-limiting hole is communicated with the axial central through hole; when the mass of the fuel flowing out of the spray hole exceeds a threshold value, the flow limiting piston compresses the ball valve and enables the ball valve to be seated on a ball valve reset spring seat, and the flow limiting hole is disconnected with the axial central through hole; when the spray hole stops spraying oil, the flow-limiting piston, the ball valve and the supporting control slide block are integrally restored to the initial positions under the action of the ball valve return spring.

2. When the coil is electrified, the balance valve rod moves upwards, the oil return hole is communicated with the oil tank, fuel oil in the control cavity returns to the oil tank through the middle oil way and the oil return hole, the needle valve body is lifted upwards, and the spray hole opens for oil injection; after the coil is powered off, the balance valve rod moves downwards under the action of the electromagnetic valve reset spring and is pressed on the upper end face of the middle block, an oil return hole is disconnected with an oil tank, meanwhile, one path of fuel in a descending high-pressure oil path enters a low-pressure port through a feedback oil path via a balance valve rod cavity and a middle oil path, the other path of fuel enters a high-pressure port through a descending oil inlet hole, the orifice plate overcomes the elasticity of the orifice plate reset spring to move downwards, the fuel in the low-pressure port and the high-pressure port enters a control cavity through an orifice hole and a side oil path, and the needle valve body is seated.

3. The diameter of the middle part of the resonance throttling hole is smaller than the diameters of the two ends of the resonance throttling hole and smaller than the diameter of the resonance through hole, and the total axial length of the resonance throttling hole and the resonance through hole is consistent.

The invention has the advantages that: the invention adopts the structure of a built-in orifice plate of the control cavity. The structure of the orifice plate can obviously reduce the dynamic oil return amount of fuel oil in the oil injection process, effectively reduce energy consumption and improve the economical efficiency of a system. The invention adopts the pressure accumulation cavity structure, can greatly improve the pressure fluctuation of the whole oil injection system, and particularly can reduce the mutual interference of each oil injector during oil injection. The invention adopts the flow limiting valve component on the structure, effectively avoids abnormal conditions such as abnormal oil injection and the like, and adds the resonance structure in the flow limiting valve component, thereby reducing the pressure fluctuation of fuel oil, ensuring the normal and stable oil injection process and simultaneously improving the fuel oil economy and the working reliability of the oil injector. The invention adjusts the switch of the oil return circuit by controlling the balance valve rod through the electromagnetic valve, is beneficial to improving the response speed and the control precision of the needle valve, provides a flexible oil injection rule and effectively improves the discharge stability and the economy of the diesel engine. A hydraulic feedback oil circuit is added in the middle block of the electromagnetic valve component and is communicated with a high-pressure oil circuit and a middle oil circuit, so that the needle valve can be opened slowly, the pressure of the system can be built quickly, the seating speed of the needle valve is improved, and the oil injector can be controlled to finish oil injection quickly. The internal part of the nozzle part is hydraulically balanced and has no static pressure difference, so that the function of no static leakage of the oil sprayer is realized.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a constrictor valve assembly;

FIG. 3 is a schematic view of a solenoid valve assembly;

FIG. 4 is a schematic view of a needle valve assembly;

fig. 5 isbase:Sub>A view frombase:Sub>A-base:Sub>A.

Detailed Description

The invention will now be described in more detail by way of example with reference to the accompanying drawings in which:

referring to fig. 1-5, the present invention includes an injector head 1, a flow restriction valve assembly 3, a solenoid valve assembly 5, a needle valve assembly 6, a locking cap 9, and an injector body 10. The injector head 1 is installed on the injector body 10 by matching connection through screw threads and sealed by a seal ring 2 placed on the injector body 10. A main oil inlet hole 12 is arranged in the oil injector head 1 and is communicated with a pressure accumulation cavity 11 in the oil injector body 10. A flow limiting valve assembly 3 is arranged below the pressure accumulation cavity 11. The flow limiting valve component 3 is arranged in the oil injector body 10, and mainly structurally comprises a retainer ring 13, a damping spring 14, a ball valve 16, a supporting control slider 17, a ball valve return spring 22, a ball valve return spring seat 23, a flow limiting piston 24 and a limiting spring seat 26. The flow-limiting hole 15 and the piston blind hole 25 are processed on the flow-limiting piston 24, and the axial center through hole 18 is processed on the supporting control slider 17, so that the fuel can smoothly flow to a lower oil way. The electromagnetic valve component 5 and the needle valve component 6 are sequentially arranged below the oil injector body 10 and are assembled and connected through a tightening cap 9. The main structure of the solenoid valve assembly 5 comprises a solenoid valve return spring seat 27, a coil 28, an armature 29, a valve seat 30, an intermediate block 34, a balance valve rod 36, an electromagnet 37 and a solenoid valve return spring 38. The armature 29 and the balance valve stem 36 are mounted in combination within the valve seat 30. The feedback oil passage 31, the oil return hole 31, the downward oil inlet hole 32, the intermediate oil passage 34, and the like are machined inside the intermediate block 35. The needle valve assembly 6 at the bottom of the fuel injector mainly comprises an orifice plate 40, an orifice plate return spring 41, a needle valve limiting sleeve 42, a needle valve body 43, a nozzle 44 and a needle valve return spring 45. The intermediate block 35 forms a control chamber 46 with the needle stop collar 42 and the needle valve body 43. The orifice plate 40 is placed within the control chamber 46. The needle valve body 43 is arranged in the nozzle 44, the upper end part of the needle valve body 43 sleeved with the needle valve return spring 45 is arranged in the needle valve cavity, and the oil containing groove 8 is arranged between the needle valve body 43 and the nozzle 44.

Fig. 1 is a schematic diagram of the overall structure of a resonance orifice plate type electric control oil injector with hydraulic feedback, wherein an oil injector body 10 is provided with a pressure accumulation cavity 11, and the pressure accumulation cavity 11 is communicated with a main oil inlet hole 12 on an oil injector head 1. The oil cavity in the flow-limiting piston 24 is communicated with the pressure accumulation cavity 11 through the piston blind hole 25 and the flow-limiting hole 15 formed on the piston blind hole. The injector head 1 and the injector body 10 are assembled through threads, and are sealed by the sealing ring 2. When the high-pressure fuel delivered in enters the interior of the injector through the main fuel inlet hole 12, the fuel passing through the pressure accumulation chamber 11 passes downward through the restrictor valve assembly 3. After flowing out of the flow limiting valve assembly 3, the fuel flows through the descending high-pressure oil way 4 to enter the control cavity 46 and the oil containing groove 8. The electromagnetic valve component 5 and the needle valve component 6 are sequentially arranged below the oil injector body 10. Within the solenoid valve assembly 5, the lifting and seating of the armature 29 and the balance valve stem 36 are controlled by electromagnetic force. When the coil 28 is energized, the balance valve stem 36 is lifted upward and the return port 32 is opened, and fuel in the control chamber 46 flows through the orifice 47 and the intermediate gallery 34 in sequence and is drained through the return port 32. Therefore, the fuel pressure in the control chamber 46 is reduced to form a fuel pressure difference with the pressure in the oil tank 8, so that the needle valve body 43 is lifted and the oil injection is started. In this process, the needle valve stopper 42 functions to limit the displacement of the needle valve body 43. When the coil 28 is powered off and the balance valve rod 36 is seated downwards, the oil return hole 32 is closed, and a part of fuel flows through the balance valve rod 36 and the intermediate oil passage 34 through the feedback oil passage 31 and enters an orifice 47 in the needle valve assembly 6; another portion of the fuel enters the high pressure port 39 on the downstream side thereof through the lower inlet port 33, and the high pressure port 39 forms an annular oil groove in the lower end surface of the intermediate block 35 surrounding the circular low pressure port 49. Due to the fact that the oil inlet of the feedback oil path 31 enables the oil pressure of the circular low-pressure port 49 to rise, the oil pressure of the annular oil groove and the high-pressure fuel oil in the circular low-pressure port 49 and the oil pressure in the control cavity 46 form a pressure difference, the orifice plate 40 moves downwards against the spring force of the orifice plate return spring 41, and the side oil path 48 of the orifice plate 40 is opened. The high-pressure fuel flowing through the middle oil passage 33 and the lower inlet port 32 rapidly enters the control chamber 46 through the annular side oil passage 48 and the orifice 47 in two paths, and the oil pressure is rapidly built up, so that the needle valve body 43 is seated, thereby ending the fuel injection process. The needle valve body 43 is mounted inside the nozzle 44 and is pressed by a needle valve return spring 45. The nozzle 44 and the solenoid valve assembly 5 are mounted inside the tightening cap 9 and are secured by the injector body 10 and the thread. The needle valve body 43 is hydraulically balanced and has no static pressure difference, so that the function of no static leakage of the oil injector is realized.

Fig. 2 is a schematic view of a portion of a constrictor valve assembly of the present invention. The device comprises a retainer ring 13, a damping spring 14, a ball valve 16, a supporting control slider 17, a ball valve reset spring seat 23, a flow limiting piston 24, a limiting spring seat 26 and the like. The restrictor valve assembly 3 is arranged inside the injector body 10 via a pressure accumulation chamber 11. The retainer ring 13 not only limits the overall restrictor valve assembly 3, but also cooperates with a limiting spring seat 26, which serves as a spring seat for the damping spring 14 on the one hand and limits the maximum displacement of the restrictor piston 24 on the other hand. Under the action of the spring preload of the damping spring 14 and the ball valve return spring 22, the ball valve 16 is matched with the lower end surface of the flow limiting piston 24 and the upper end surface of the supporting control slider 17. The ball return spring seat 23 is pressed against the bottom by the spring force of the ball return spring 22, and the seat surface of the ball 16 is formed at the upper variable cross section thereof. High-pressure fuel enters the blind piston bore 25 in the metering piston 24 via the pressure accumulation chamber 11, flows through the metering orifice 15 and enters the axially central through-bore 18 of the supporting control slide 17. The fuel flowing out of the axial central through hole 18 passes through the resonance through hole 19 and the resonance orifice 21 into the transition oil chamber 20. By providing the machined resonance through hole 19 and the resonance orifice 21, the amplitude of the fuel pressure wave passing through the two holes is reduced. In addition, there is one section aperture in the resonance orifice 21 of processing to be littleer than resonance through-hole 19, so the throttle effect is stronger, has resulted in the fuel velocity of flow that flows through from two holes different for the fuel pressure wave of original same phase has produced the phase difference, and two strands of fuel pressure waves offset each other after the stack, and then make the pressure oscillation reduce greatly. The fuel flowing out of the transition oil chamber 20 is led to the lower oil passage through the lower high-pressure oil passage 4. When the injector is operating normally, the nozzle hole 9 injects fuel, so that the fuel pressure in the transition oil chamber 25 is reduced. Due to the throttling effect of the flow limiting hole 15 on fuel, the pressure of the fuel in the piston blind hole 25 in the flow limiting piston 24 and the pressure accumulation cavity 11 is increased, and a pressure difference is formed between the pressure of the fuel in the transition oil cavity 20, so that the flow limiting piston 24, the ball valve 16 and the supporting control slider 17 are integrally displaced downwards, fuel sprayed by an oil injector is compensated to a certain extent, and the ball valve 16 cannot be seated on the ball valve reset spring seat 23. When the fuel injection stops working, the pressure difference of the upper surface and the lower surface of the flow-limiting piston 24 is gradually reduced along with the flow of the fuel through the flow-limiting hole 15, and the flow-limiting piston 24, the ball valve 16 and the supporting control slide block 17 are restored to the initial positions under the action of the ball valve return spring 22. When the spray hole 7 continuously sprays fuel, the mass of the flowing fuel exceeds a threshold value, so that the fuel injector is in an abnormal working state, the oil pressure of the transition oil cavity 20 below the flow limiting piston 24 is rapidly reduced, an up-down pressure difference is formed, the flow limiting piston 24 presses the ball valve 16 to be seated on the ball valve reset spring seat 23, and the fuel is prevented from continuously flowing. Because the fuel supply is cut off, the fuel injector stops working, thereby reducing the occurrence of abnormal fuel injection to a certain extent and improving the fuel economy and the working stability of the fuel injector.

Fig. 3 is a schematic view of a part of the structure of the solenoid valve assembly of the present invention. The electromagnetic valve comprises an electromagnetic valve return spring seat 27, a coil 28, an armature 29, a valve seat 30, an intermediate block 35, a balance valve rod 36, an electromagnet 37, an electromagnetic valve return spring 38 and the like. The solenoid valve return spring seat 27, the coil 28, the electromagnet 37 and the solenoid valve return spring 38 are built in the injector body 10, wherein the solenoid valve return spring seat 27 is fastened to the topmost end of the solenoid valve by a screw thread. A solenoid return spring 38 is disposed between the solenoid return spring seat 27 and the armature 29, and the armature 29 and the balance valve rod 36 are disposed inside the valve seat 30 below the injector body 10. The intermediate block 35 is located below the valve seat 30. When the fuel injector starts to inject fuel, the coil 28 is electrified to form a magnetic circuit with the armature 29 and the electromagnet 37, electromagnetic force is generated, the balance valve rod 36 is attracted to move upwards, and the oil return hole 32 in the middle block 35 is opened. At this time, the fuel in the control chamber 46 sequentially passes through the intermediate oil passage 34 and the oil return hole 32 and is returned to the oil tank, and due to the throttling effect of the intermediate oil passage 34, the fuel pressure in the control chamber 46 is slowly reduced, the upper surface of the needle valve body 43 is reduced in pressure, and a pressure difference is formed between the upper surface of the needle valve body and the fuel pressure in the oil containing groove 8. Under the action of the pressure difference, the needle valve body 43 is lifted up slowly, and the spray hole 7 is opened to spray oil. When the injector stops injecting fuel, the coil 28 is powered off, and the armature 29 and the balance valve rod 36 are tightly combined into a whole, so that the armature 29 and the balance valve rod jointly move downwards under the action of the spring pre-tightening force of the electromagnetic valve return spring 38, are tightly pressed on the upper end face of the intermediate block 35 and block the oil return hole 32. Meanwhile, two paths of oil are fed into the middle block 35, and one path of oil flows through the middle oil path 34 through the feedback oil path 31 and enters the lower needle valve assembly; and the other path is to enter a lower oil path through a lower oil inlet hole 33. In the whole oil injection process, high-pressure fuel oil always enters the upper oil cavity through the feedback oil path 31, so that the oil pressure reduction rate of the control cavity 46 is reduced, the pressure drop of the control cavity 46 at the initial stage of oil injection is reduced and slowed, and the generation of nitrogen oxides is reduced; when oil injection is finished, the pressure building speed of a normal single oil inlet hole to the control cavity 46 is increased, the seating speed of the needle valve is increased, and the response speed of the needle valve is optimized.

FIG. 4 is a schematic view of a portion of a needle valve assembly according to the present invention. The needle valve assembly 5 mainly comprises an orifice plate 40, an orifice plate return spring 41, a needle valve limit sleeve 42, a needle valve body 43, a nozzle 44 and a needle valve return spring 45. Before the injection begins, the entire control chamber 46 is hydraulically balanced and filled with high pressure fuel. The orifice plate 40 is pushed up by the biasing force of the orifice plate return spring 41 and blocks the high pressure port 39. When the coil 28 is energized, the oil return hole 32 is opened after the balanced valve stem 36 of the solenoid valve is lifted. The fuel in the control chamber 46 flows through the orifice 47 of the orifice plate 40 and the intermediate oil passage 34 in this order to be returned. As the fuel pressure in the control chamber 46 decreases, the needle valve body 43 lifts upward against the spring biasing force of the needle valve return spring 45, and fuel injection begins. During the injection, the presence of the orifice 47 makes the fuel pressure in the control chamber 46 higher than the fuel pressure in the intermediate channel 34, and the combined force of the pressure difference and the spring force is sufficient to overcome the fuel pressure in the annular groove formed by the high-pressure port 39, so that the orifice plate 40 is pressed against the lower end face of the intermediate block 35 at all times, blocking the downward inlet port 33 from entering the annular groove on the downstream side thereof, preventing the entry of high-pressure fuel, and effectively reducing the amount of high-pressure fuel flowing back to the low-pressure tank during the injection. When the coil 28 is de-energized and the balanced valve stem 36 of the solenoid is seated, the oil return hole 32 is blocked. Due to the presence of the feedback oil passage 31, the high-pressure fuel entering through the feedback oil passage 31 causes the oil pressure of the intermediate oil passage 34 to rise until the orifice 40 opens. The high pressure fuel in the high pressure port 39 and the fuel pressure in the control chamber 46 form a pressure difference, so that the orifice plate 40 overcomes the spring pre-tightening force of the orifice plate return spring 41, the orifice plate 40 moves downwards to be opened, and meanwhile, the annular side oil passage 48 around the orifice plate 40 is opened. One path of high-pressure fuel flows through the descending oil inlet hole 33, the other path of high-pressure fuel sequentially flows through the feedback oil path 31 and the middle oil path 34, and finally the high-pressure fuel enters the control cavity 46 through the throttle hole 47 and the annular side oil path 48, so that the oil pressure in the control cavity 46 is quickly established, the needle valve is quickly seated, and the fuel injection is stopped.

Fig. 5 is an enlarged view of the sectionbase:Sub>A-base:Sub>A of the needle valve body 43. The arc-shaped surface can play a good role in guiding.

According to the working process, the orifice plate 40 structure arranged in the needle valve assembly 6 in the oil injection process of the pressure accumulating orifice plate type electric control oil injector with hydraulic feedback greatly reduces the dynamic oil return amount in the oil injection process and ensures the characteristic of micro-dynamic oil return. Through the two-way oil inlet of the feedback oil path 31 and the downlink oil inlet 33 in the electromagnetic valve assembly 5, the two-way oil inlet of the throttling hole 47 of the pore plate 40 of the needle valve assembly 6 and the two-way oil inlet of the annular side oil path 48, the pressure build-up process of the control cavity 46 is greatly improved, and the response speed of the needle valve seating is improved. In addition, the flow limiting valve assembly 3 arranged in the oil sprayer body 10 effectively prevents the abnormal oil spraying state from continuing, wherein the addition of the resonance structure effectively reduces the fuel pressure fluctuation, and ensures the stability and the fuel economy in the working process. The whole oil injection process is controlled by an electromagnetic valve, and the electromagnetic force is utilized to drive the balance valve rod 36 to move, so that the requirements of high response speed, high control precision and variable oil injection rule in the oil injection process are met. When the invention is applied to a common rail system, the pressure fluctuation of the common rail can be effectively reduced by adopting the structure of the pressure storage cavity 11 under the condition of large oil injection quantity, thereby reducing the phenomena of uniformity and stability reduction of the oil injection process of each cylinder.

Claims

1. The utility model provides a take automatically controlled sprayer of resonant orifice plate formula of hydraulic feedback which characterized in that: the oil sprayer comprises an oil sprayer head, an oil sprayer body, a flow limiting valve assembly, a solenoid valve assembly, a needle valve assembly and a downlink high-pressure oil way, wherein the oil sprayer head is arranged above the oil sprayer body, a main oil inlet hole is formed in the oil sprayer head, a pressure storage cavity is formed in the oil sprayer body, the main oil inlet hole is communicated with the pressure storage cavity, the flow limiting valve assembly is arranged in the pressure storage cavity, the solenoid valve assembly and the needle valve assembly are sequentially arranged at the lower end of the oil sprayer body, a tightening cap is positioned outside the solenoid valve assembly and the needle valve assembly, and the upper end of the tightening cap is connected with the lower end of the oil sprayer body in a threaded connection mode;

the electromagnetic valve component comprises an electromagnet, a coil, an armature, a balance valve rod, a valve seat and an intermediate block, wherein the coil is wound on the electromagnet, an electromagnetic valve reset spring seat is arranged above the electromagnet, the armature is arranged below the electromagnet, an electromagnetic valve reset spring is arranged between the armature and the electromagnetic valve reset spring seat, the balance valve rod is positioned in the valve seat, the upper end part of the balance valve rod is fixedly connected with the armature, the intermediate block is arranged below the valve seat, a balance valve rod cavity is formed among the lower end part of the balance valve rod, the valve seat and the intermediate block, an oil return hole, an intermediate oil way, a lower oil inlet hole and a feedback oil way are arranged in the intermediate block, the intermediate oil way and the feedback oil way are respectively and directly communicated with the balance valve rod cavity, and the oil return hole is communicated or disconnected with the intermediate oil way and an oil tank under the control of the balance valve rod;

the middle oil way is communicated with the low-pressure port, the descending oil inlet hole is communicated with the high-pressure port, the upper end of the descending high-pressure oil way is communicated with the transition oil cavity and is communicated with the oil containing groove through the oil sprayer body, the valve seat, the middle block and the nozzle, and the descending oil inlet hole and the feedback oil way are respectively communicated with the descending high-pressure oil way;

when the spray hole sprays oil, the fuel pressure of the transition oil cavity is reduced, the whole of the flow-limiting piston, the ball valve and the supporting control slide block moves downwards, the ball valve is not seated on the ball valve reset spring seat, and the flow-limiting hole is communicated with the axial central through hole; when the mass of the fuel flowing out of the spray hole exceeds a threshold value, the flow limiting piston compresses the ball valve and enables the ball valve to be seated on a ball valve reset spring seat, and the flow limiting hole is disconnected with the axial central through hole; when the spray hole stops spraying oil, the flow-limiting piston, the ball valve and the supporting control slide block are integrally restored to the initial positions under the action of the ball valve return spring.

2. The resonant orifice plate type electric control fuel injector with hydraulic feedback as set forth in claim 1, is characterized in that: when the coil is electrified, the balance valve rod moves upwards, the oil return hole is communicated with the oil tank, fuel oil in the control cavity returns to the oil tank through the middle oil way and the oil return hole, the needle valve body is lifted upwards, and the spray hole opens for oil injection; after the coil is powered off, the balance valve rod moves downwards under the action of the electromagnetic valve reset spring and is pressed on the upper end face of the middle block, the oil return hole is disconnected with the oil tank, meanwhile, one path of fuel in the descending high-pressure oil path enters the low-pressure port through the balance valve rod cavity and the middle oil path, the other path of fuel enters the high-pressure port through the descending oil inlet hole, the orifice plate overcomes the elasticity of the orifice plate reset spring to move downwards, the fuel in the low-pressure port and the high-pressure port enters the control cavity through the orifice hole and the side oil path, and the needle valve body is seated.

3. The electrically controlled fuel injector with the hydraulic feedback hole plate as claimed in claim 1 or 2, wherein: the diameter of the middle part of the resonance throttling hole is smaller than the diameters of the two ends of the resonance throttling hole and smaller than the diameter of the resonance through hole, and the total axial length of the resonance throttling hole and the resonance through hole is consistent.