Common rail injector

Abstract

The present invention discloses a common rail fuel injector, wherein the electromagnetic valve assembly is connected to the top of the fuel injector body, the filter assembly is connected to the side of the fuel injector body, the common rail pair is arranged at the bottom of the fuel injector body, the piston assembly is arranged inside the fuel injector body, and the lower end of the piston assembly is connected to the common rail pair; the filter assembly is provided with a filter, and the filter is pressed into the fuel injector body by interference fit; the needle valve is arranged inside the needle valve body, an oil storage tank is formed between the needle valve body and the needle valve, and a spray hole is formed at the bottom of the needle valve; the control piston is arranged inside the piston sleeve, and the control chamber is formed between the piston sleeve and the top of the control piston; the oil inlet metering hole is arranged on the side of the piston sleeve, and the oil inlet metering hole is connected to the control chamber; the oil outlet metering hole is arranged on the top of the piston sleeve, and the oil outlet metering hole is connected to the control chamber. The present invention can accurately control the injection time and the amount of fuel injection, and can achieve better emission indicators, filter impurities in high-pressure oil, and extend the service life.

Description

Technical Field

[0001] The invention relates to a common rail fuel injector and belongs to the technical field of automobile engines. Background Art

[0002] With the rapid increase of urban transportation vehicles and ships in various countries around the world, exhaust gas emitted by diesel engines has become the main source of pollution to the earth's environment. Countries around the world have also begun to find and take effective technical measures to actively reduce and control pollutant emissions. Diesel engine common rail electronic fuel injection technology is a relatively successful new technology for controlling pollution emissions. After 2015, my country has implemented the National IV emission regulations for road vehicles and the National III regulations for non-road vehicles. Simple mechanical injectors can no longer meet national emission requirements. Choosing electronically controlled high-pressure common rail technology has become an inevitable trend in the diesel engine industry.

[0003] The injector is an extremely important component that affects the performance indicators and working reliability of the engine. The development of injectors in my country is mainly centered on the design and manufacture of mechanical injectors. The original mechanical injector relies on the pressure regulating effect of the spring to achieve injection. The pressure regulating spring is located at the upper part of the injector. Due to the long distance between the spring and the needle valve, this structure must be bridged by a long push rod. The opening pressure is fixed and one injection is performed in each working cycle. The push rod is long and has a large mass, resulting in large inertia, which cannot achieve the rapid opening and closing of the needle valve. If the needle valve is not closed in time, the high-temperature gas in the combustion chamber is easy to flow back into the nozzle pair, causing carbon deposits to burn the sealing seat surface, and at the same time, it is not possible to achieve a good emission index.

[0004] Domestic electronically controlled diesel engine systems still face many challenges, such as immature manufacturing processes and small batch sizes; difficulty in ensuring fuel quality; and low levels of diesel engine after-processing technology.

[0005] In summary, a new common rail injector technical solution is urgently needed. Summary of the invention

[0006] The present invention aims at the deficiencies in the prior art and provides a common rail injector, which can accurately control the injection time and the injection amount, achieve better emission indicators, filter impurities in the high-pressure oil, and extend the service life.

[0007] The technical solution of the present invention to solve the above technical problems is as follows: a common rail injector, comprising an injector body, a solenoid valve assembly, a filter assembly, a common rail pair and a piston assembly; the solenoid valve assembly is connected to the top of the injector body, the filter assembly is connected to the side of the injector body, the common rail pair is arranged at the bottom of the injector body, the piston assembly is arranged inside the injector body, and the lower end of the piston assembly is connected to the common rail pair;

[0008] The filter assembly is provided with a filter screen, and the filter screen is pressed into the co-injector body by interference fit;

[0009] The common rail pair comprises a needle valve body, a needle valve, an oil storage tank and a spray hole, wherein the needle valve is arranged inside the needle valve body, the oil storage tank is formed between the needle valve body and the needle valve, and the spray hole is formed at the bottom of the needle valve;

[0010] The piston assembly includes a piston sleeve, a control piston, a control chamber, an oil inlet metering hole and an oil outlet metering hole; the control piston is arranged inside the piston sleeve, and the control chamber is formed between the piston sleeve and the top of the control piston; the oil inlet metering hole is arranged on the side of the piston sleeve, and the oil inlet metering hole is connected to the control chamber; the oil outlet metering hole is arranged on the top of the piston sleeve, and the oil outlet metering hole is connected to the control chamber.

[0011] As a preferred solution for the common rail injector, the solenoid valve assembly includes a sphere, a control ball seat, an armature, a locking nut, a spring body and a driving component; the sphere is arranged above the oil outlet metering hole; the control ball seat is arranged above the sphere, the upper end of the control ball seat is connected to the armature, and the control ball seat is located inside the upper end of the injector body; the armature is arranged inside the locking nut; the spring body is arranged above the armature; the driving component is arranged at the upper end of the locking nut, the spring body is connected to the driving component, and a locking nut is connected between the driving component and the injector body; the outer side of the locking nut is connected to the solenoid valve protective cap.

[0012] As a preferred solution for the common rail injector, an O-ring is provided between the injector body and the locking nut, a first lift pressure regulating gasket is connected between the injector body and the driving component; a solenoid valve pressure regulating gasket is connected between the spring body and the driving component; and a solenoid valve sealing ring is connected between the driving component and the locking nut.

[0013] As a preferred solution of the common rail injector, a sealing ring is connected between the piston sleeve and the injector body, and a baffle is provided below the sealing ring.

[0014] As a preferred solution for the common rail injector, a second lift pressure regulating gasket is provided between the control piston and the needle valve, a push rod is provided on the periphery of the connection between the control piston and the needle valve, a pressure regulating spring is provided above the push rod, and a third pressure regulating gasket is provided between the pressure regulating spring and the injector body.

[0015] As a preferred solution of the common rail fuel injector, a tight cap is sleeved on the lower outer side of the fuel injector body, a cylinder gasket is arranged below the tight cap, and a fuel injection nozzle protective cap is connected below the cylinder gasket;

[0016] The injector body is provided with an oil inlet protective cap at the connection of the filter assembly; and an O-ring is provided at the periphery of the injector body.

[0017] As a preferred solution of the common rail injector, the lifting speed of the needle valve is controlled according to the flow difference between the oil outlet metering hole and the oil inlet metering hole, and the closing speed of the needle valve is controlled according to the flow of the oil inlet metering hole.

[0018] As a preferred solution for the common rail injector, the fuel from the high-pressure oil circuit enters the common rail injector body through the filter assembly, then enters the control chamber through the oil inlet metering hole of the piston assembly and forms pressure on the control chamber, and the pressure in the control chamber drops when the fuel flows out of the control chamber through the oil outlet metering hole.

[0019] As a preferred solution for the common rail injector, when the solenoid valve assembly is energized, the armature overcomes the elastic force of the spring body and lifts upward to open the control ball seat, the upward force acting on the needle valve is greater than the downward force acting on the control piston, the needle valve is lifted upward under the action of the fuel, and the fuel flows through the spray hole to start spraying; when the solenoid valve assembly is de-energized, the armature falls to gradually increase the pressure in the control chamber, and the needle valve is closed and the spraying stops under the drive of the control piston.

[0020] As a preferred solution for the common rail injector, the needle valve is not directly controlled by hydraulic pressure amplification, and the manner in which the hydraulic pressure amplification does not directly control the needle valve is: the fuel is allowed to flow out through the oil metering hole through the solenoid valve assembly, and then the pressure in the control chamber is reduced to open the needle valve to form a spray.

[0021] The invention is provided with a fuel injector body, a solenoid valve assembly, a filter assembly, a common rail pair and a piston assembly; the solenoid valve assembly is connected to the top of the fuel injector body, the filter assembly is connected to the side of the fuel injector body, the common rail pair is arranged at the bottom of the fuel injector body, the piston assembly is arranged inside the fuel injector body, and the lower end of the piston assembly is connected to the common rail pair; the filter assembly is provided with a filter, and the filter is pressed into the fuel injector body by interference fit; the common rail pair comprises a needle valve body, a needle valve, an oil storage tank and a spray hole, the needle valve is arranged inside the needle valve body, an oil storage tank is formed between the needle valve body and the needle valve, and a spray hole is formed at the bottom of the needle valve; the piston assembly comprises a piston sleeve, a control piston, a control chamber, an oil inlet metering hole and an oil outlet metering hole; the control piston is arranged inside the piston sleeve, and the control chamber is formed between the piston sleeve and the top of the control piston; the oil inlet metering hole is arranged at the side of the piston sleeve, and the oil inlet metering hole is connected to the control chamber; the oil outlet metering hole is arranged at the top of the piston sleeve, and the oil outlet metering hole is connected to the control chamber. The present invention can accurately control the injection time and injection amount of the common rail injector, achieve good emission indicators, reduce environmental pollution, and can filter impurities in the high-pressure oil through the filter screen to extend the service life of the common rail injector. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0023] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0024] Figure 1 A front full sectional view of a common rail injector provided in an embodiment of the present invention;

[0025] Figure 2 A partial enlarged view of the filter screen of the common rail injector provided in an embodiment of the present invention;

[0026] Figure 3 It is a partial enlarged schematic diagram of the intersection of the top of the injector body, the solenoid valve assembly and the piston assembly of the common rail injector provided in an embodiment of the present invention;

[0027] Figure 4 A full cross-sectional view of a common rail couple of a common rail injector provided in an embodiment of the present invention;

[0028] Figure 5 A full cross-sectional view of a piston assembly of a common rail injector provided in an embodiment of the present invention;

[0029] Figure 6 The figure is a schematic diagram of the appearance of the common rail injector provided in an embodiment of the present invention.

[0030] In the figure, 1, the main body of the injector; 2, the solenoid valve assembly; 3, the filter assembly; 4, the common rail pair; 5, the piston assembly; 6, the filter; 7, the main body of the needle valve; 8, the needle valve; 9, the oil tank; 10, the spray hole; 11, the piston sleeve; 12, the control piston; 13, the control chamber; 14, the oil inlet metering hole; 15, the oil outlet metering hole; 16, the ball; 17, the control ball seat; 18, the armature; 19, the locking screw sleeve; 20, the spring body; 21, Driving component; 22. Locking nut; 23. Solenoid valve protective cap; 24. O-ring; 25. First lift pressure regulating gasket; 26. Solenoid valve pressure regulating gasket; 27. Solenoid valve sealing ring; 28. Sealing ring; 29. ​​Baffle; 30. Second lift pressure regulating gasket; 31. Push rod; 32. Pressure regulating spring; 33. Third pressure regulating gasket; 34. Tightening cap; 35. Cylinder gasket; 36. Injection nozzle protective cap; 37. Oil inlet protective cap; 38. Body O-ring. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6, a common rail fuel injector is provided, comprising a fuel injector body 1, a solenoid valve assembly 2, a filter assembly 3, a common rail pair 4 and a piston assembly 5; the solenoid valve assembly 2 is connected to the top of the fuel injector body 1, the filter assembly 3 is connected to the side of the fuel injector body 1, the common rail pair 4 is arranged at the bottom of the fuel injector body 1, the piston assembly 5 is arranged inside the fuel injector body 1, and the lower end of the piston assembly 5 is connected to the common rail pair 4. The filter assembly 3 is provided with a filter 6, and the filter 6 is pressed into the fuel injector body 1 by interference fit. The common rail pair 4 comprises a needle valve body 7, a needle valve 8, an oil storage tank 9 and a spray hole 10, the needle valve 8 is arranged inside the needle valve body 7, the oil storage tank 9 is formed between the needle valve body 7 and the needle valve 8, and the spray hole 10 is formed at the bottom of the needle valve 8. The piston assembly 5 includes a piston sleeve 11, a control piston 12, a control chamber 13, an oil inlet metering hole 14 and an oil outlet metering hole 15; the control piston 12 is arranged inside the piston sleeve 11, and the control chamber 13 is formed between the piston sleeve 11 and the top of the control piston 12; the oil inlet metering hole 14 is arranged on the side of the piston sleeve 11, and the oil inlet metering hole 14 is connected to the control chamber 13; the oil outlet metering hole 15 is arranged on the top of the piston sleeve 11, and the oil outlet metering hole 15 is connected to the control chamber 13.

[0034] In one embodiment of the common rail injector, the solenoid valve assembly 2 includes a sphere 16, a control ball seat 17, an armature 18, a locking screw sleeve 19, a spring body 20 and a driving component 21; the sphere 16 is arranged above the oil metering hole 15; the control ball seat 17 is arranged above the sphere 16, the upper end of the control ball seat 17 is connected to the armature 18, and the control ball seat 17 is located inside the upper end of the injector body 1; the armature 18 is arranged inside the locking screw sleeve 19; the spring body 20 is arranged above the armature 18; the driving component 21 is arranged at the upper end of the locking screw sleeve 19, the spring body 20 is connected to the driving component 21, and a locking nut 22 is connected between the driving component 21 and the injector body 1; the outer side of the locking nut 22 is connected to a solenoid valve protective cap 23, and the solenoid valve protective cap 23 protects the solenoid valve assembly 2.

[0035] Specifically, the fuel from the high-pressure oil circuit enters the injector body 1 through the filter assembly 3, and then enters the control chamber 13 through the oil inlet metering hole 14 of the piston assembly 5 to form pressure on the control chamber 13. When the fuel flows out of the control chamber 13 through the oil outlet metering hole 15, the pressure of the control chamber 13 drops.

[0036] Specifically, when the solenoid valve assembly 2 is energized, the armature 18 overcomes the elastic force of the spring body 20 and lifts upward to open the control ball seat 17. The upward force acting on the needle valve 8 is greater than the downward force acting on the control piston 12. The needle valve 8 is lifted upward under the action of the fuel, and the fuel flows through the spray hole 10 to start spraying.

[0037] When the electromagnetic valve assembly 2 is powered off, the armature 18 falls to gradually increase the pressure in the control chamber 13, and the needle valve 8 is closed and the fuel injection is stopped under the drive of the control piston 12. The needle valve 8 is not directly controlled by hydraulic pressure amplification. The hydraulic pressure amplification does not directly control the needle valve 8 in the following manner: the fuel is made to flow out through the fuel metering hole 15 through the electromagnetic valve assembly 2, and then the pressure in the control chamber 13 is reduced to open the needle valve 8 to form injection.

[0038] Specifically, when the solenoid valve assembly 2 is not energized, the pressure in the control chamber 13 is the same as the pressure in the oil tank 9 , that is, the pressure acting on the control piston 12 is the same as the pressure acting on the needle valve 8 .

[0039] In one embodiment of the common rail injector, an O-ring 24 is provided between the injector body 1 and the locking nut 22, and the O-ring 24 serves as a connection seal between the injector body 1 and the locking nut 22. A first lift pressure regulating gasket 25 is connected between the injector body 1 and the drive component 21, and the first lift pressure regulating gasket 25 serves as a pressure regulator between the injector body 1 and the drive component 21. A solenoid valve pressure regulating gasket 26 is connected between the spring body 20 and the drive component 21, and the solenoid valve pressure regulating gasket 26 serves as a pressure regulator between the spring body 20 and the drive component 21. A solenoid valve sealing ring 27 is connected between the drive component 21 and the locking nut 22. The solenoid valve sealing ring 27 serves as a seal between the drive component 21 and the locking nut 22.

[0040] In one embodiment of the common rail fuel injector, a sealing ring 28 is connected between the piston sleeve 11 and the fuel injector body 1, and a baffle 29 is provided below the sealing ring 28. The sealing ring 28 plays a sealing role between the piston sleeve 11 and the fuel injector body 1. When the sealing ring 28 is subjected to external force, it will be squeezed into the inner hole of the dynamic ring and the shaft gap, and the baffle 29 prevents the sealing ring 28 from deforming and affecting the sealing effect.

[0041] In one embodiment of the common rail injector, a second lift pressure regulating gasket 30 is provided between the control piston 12 and the needle valve 8, and the second lift pressure regulating gasket 30 plays a role in regulating the pressure between the control piston 12 and the needle valve 8. A push rod 31 is provided at the periphery of the connection between the control piston 12 and the needle valve 8, and a pressure regulating spring 32 is provided above the push rod 31. A third pressure regulating gasket 33 is provided between the pressure regulating spring 32 and the injector body 1, and the pressure regulating spring 32 and the third pressure regulating gasket 33 play a role in buffering the needle valve 8.

[0042] In one embodiment of the common rail fuel injector, a tight cap 34 is sleeved on the lower outer side of the fuel injector body 1, a cylinder gasket 35 is provided below the tight cap 34, a fuel injection nozzle cap 36 is connected below the cylinder gasket 35, and the fuel injection nozzle cap 36 plays a role in protecting the fuel injection nozzle. The fuel injector body 1 is provided with an oil inlet cap 37 at the connection of the filter assembly 3, and the oil inlet cap 37 plays a role in protecting the oil inlet; the outer periphery of the fuel injector body 1 is provided with an O-ring 38, and the O-ring 38 reduces the friction of the fuel injector body 1 during use.

[0043] In one embodiment of the common rail injector, the lifting speed of the needle valve 8 is controlled according to the flow difference between the oil outlet metering hole 15 and the oil inlet metering hole 14, and the closing speed of the needle valve 8 is controlled according to the flow of the oil inlet metering hole 14. The flow difference between the oil outlet metering hole 15 and the oil inlet metering hole 14 of the control chamber 13 determines the lifting speed of the needle valve 8, and the flow of the oil inlet metering hole 14 determines the closing speed of the needle valve 8.

[0044] The working process of the common rail injector of the embodiment of the present invention is as follows:

[0045] The high-pressure fuel from the high-pressure common rail pipe flows into the injector body through the filter assembly 3, flows into the oil tank 9 of the common rail couple 4 through the oil channel hole, and flows to the control chamber 13 through the oil inlet metering hole 14 on the piston assembly 5. The control chamber 13 is connected to the fuel circuit and passes through an oil outlet metering hole 15 whose switch is controlled by the solenoid valve assembly 2. When the oil outlet metering hole 15 is closed, the fuel liquid pressure acting on the control piston 12 of the piston assembly 5 exceeds its force on the pressure-bearing surface of the needle valve 8, so the needle valve 8 is forced to move downward and isolate and seal the high-pressure channel from the combustion chamber. When the solenoid valve assembly 2 of the common rail injector is not energized, the spring force of the solenoid valve coil and the solenoid valve spring body 20 act together on the armature 18, and the armature 18 moves downward along the locking screw sleeve 19 to press the control ball seat 17 so that the ball 16 is pressed on the oil outlet metering hole 15, and the oil outlet metering hole 15 is closed. When the solenoid valve assembly 2 of the injector is energized, the magnetic force generated by the solenoid valve assembly 2 causes the armature 18 to overcome the elastic force of the spring body 20 and move upward, the control ball seat 17 opens, the ball 16 is lifted, and the oil metering hole 15 is opened, thereby causing the pressure in the control chamber 13 to drop, so the fuel liquid pressure on the control piston 12 also decreases. Once the fuel liquid pressure drops below the force acting on the pressure-bearing surface of the needle valve 8, the needle valve 8 is opened, and the fuel is sprayed into the combustion chamber through the spray hole 10.

[0046] When the oil metering hole 15 is opened, the fuel will flow from the control chamber 13 of the piston assembly 5 into the cavity above it, and the fuel will return to the fuel tank through the oil return pipe. The oil metering hole 15 destroys the absolute pressure balance, and finally the pressure in the control chamber 13 of the piston assembly 5 also drops. This causes the pressure in the control chamber 13 of the piston assembly 5 to be lower than the pressure of the oil tank 9 which still has the same pressure level as the high-pressure common rail pipe. The reduction of the pressure in the control chamber 13 of the piston assembly 5 leads to a reduction in the force acting on the control piston 12, and finally the needle valve 8 of the common rail injector opens and the injection begins. The opening speed of the needle valve 8 depends on the different flow rates when flowing through the oil metering hole 14 and the oil metering hole 15 of the control chamber 13. The control piston 12 reaches the upper stop position, and is still maintained by the buffer generated by the fuel flow between the oil metering hole 14 and the oil metering hole 15. At this time, the injector common rail couple 4 is fully opened, and the fuel is sprayed into the combustion chamber at almost the same pressure as in the high-pressure common rail pipe. Due to the precise control of the ECU, the common rail injector can complete multiple injections within one working cycle, and can realize pre-injection, main injection and post-injection, which plays a vital role in reducing engine emissions.

[0047] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A common rail injector, characterized in that: The invention comprises an injector body (1), a solenoid valve assembly (2), a filter assembly (3), a common rail assembly (4) and a piston assembly (5); the solenoid valve assembly (2) is connected to the top of the injector body (1), the filter assembly (3) is connected to the side of the injector body (1), the common rail assembly (4) is arranged at the bottom of the injector body (1), the piston assembly (5) is arranged inside the injector body (1), and the lower end of the piston assembly (5) is connected to the common rail assembly (4); The filter assembly (3) is provided with a filter (6), and the filter (6) is pressed into the injector body (1) through an interference fit; The common rail pair (4) comprises a needle valve body (7), a needle valve (8), an oil storage groove (9) and a spray hole (10); the needle valve (8) is arranged inside the needle valve body (7); the oil storage groove (9) is formed between the needle valve body (7) and the needle valve (8); and the spray hole (10) is formed at the bottom of the needle valve (8); The piston assembly (5) comprises a piston sleeve (11), a control piston (12), a control chamber (13), an oil inlet metering hole (14) and an oil outlet metering hole (15); the control piston (12) is arranged inside the piston sleeve (11), and the control chamber (13) is formed between the piston sleeve (11) and the top of the control piston (12); the oil inlet metering hole (14) is arranged on the side of the piston sleeve (11), and the oil inlet metering hole (14) is connected to the control chamber (13); the oil outlet metering hole (15) is arranged on the top of the piston sleeve (11), and the oil outlet metering hole (15) is connected to the control chamber (13); The solenoid valve assembly (2) comprises a ball (16), a control ball seat (17), an armature (18), a locking screw sleeve (19), a spring body (20) and a driving component (21); An O-ring (24) is provided between the fuel injector body (1) and the locking nut (22); a first lift pressure regulating gasket (25) is connected between the fuel injector body (1) and the driving component (21); a solenoid valve pressure regulating gasket (26) is connected between the spring body (20) and the driving component (21); and a solenoid valve sealing ring (27) is connected between the driving component (21) and the locking nut (22); A second lift pressure regulating gasket (30) is provided between the control piston (12) and the needle valve (8); a push rod (31) is provided on the periphery of the connection between the control piston (12) and the needle valve (8); a pressure regulating spring (32) is provided above the push rod (31); and a third pressure regulating gasket (33) is provided between the pressure regulating spring (32) and the injector body (1); The lifting speed of the needle valve (8) is controlled according to the flow difference between the oil outlet metering hole (15) and the oil inlet metering hole (14), and the closing speed of the needle valve (8) is controlled according to the flow of the oil inlet metering hole (14).

2. A common rail injector according to claim 1, characterized in that: The sphere (16) is arranged above the oil metering hole (15); the control ball seat (17) is arranged above the sphere (16); the upper end of the control ball seat (17) is connected to the armature (18); the control ball seat (17) is located inside the upper end of the injector body (1); the armature (18) is arranged inside the locking screw sleeve (19); the spring body (20) is arranged above the armature (18); the driving component (21) is arranged at the upper end of the locking screw sleeve (19); the spring body (20) is connected to the driving component (21); a locking nut (22) is connected between the driving component (21) and the injector body (1); and the outer side of the locking nut (22) is connected to a solenoid valve protective cap (23).

3. A common rail injector according to claim 1, characterized in that: A sealing ring (28) is connected between the piston sleeve (11) and the fuel injector body (1), and a baffle (29) is provided below the sealing ring (28).

4. A common rail injector according to claim 1, characterized in that: A tightening cap (34) is sleeved on the lower outer side of the fuel injector body (1), a cylinder gasket (35) is provided below the tightening cap (34), and a fuel injection nozzle protective cap (36) is connected below the cylinder gasket (35); The injector body (1) is provided with an oil inlet protective cap (37) at the connection port of the filter assembly (3); and an O-ring (38) is provided on the periphery of the injector body (1).

5. A common rail injector according to claim 1, characterized in that: Fuel from the high-pressure oil circuit enters the injector body through the filter assembly (3), then enters the control chamber (13) through the oil inlet metering hole (14) of the piston assembly (5) and forms pressure on the control chamber (13). When the fuel flows out of the control chamber (13) through the oil outlet metering hole (15), the pressure in the control chamber (13) decreases.

6. A common rail injector according to claim 2, characterized in that: When the solenoid valve assembly (2) is powered on, the armature (18) overcomes the elastic force of the spring body (20) and lifts upward to open the control ball seat (17). The upward force acting on the needle valve (8) is greater than the downward force acting on the control piston (12). The needle valve (8) is lifted upward under the action of the fuel, and the fuel flows through the spray hole (10) to start spraying. When the solenoid valve assembly (2) is powered off, the armature (18) falls to gradually increase the pressure in the control chamber (13). The needle valve (8) is closed and the spraying of fuel is stopped under the drive of the control piston (12).

7. A common rail injector according to claim 1, characterized in that: The needle valve (8) is not directly controlled by hydraulic pressure amplification, and the manner in which the hydraulic pressure amplification does not directly control the needle valve (8) is as follows: the fuel is caused to flow out through the oil metering hole (15) through the solenoid valve assembly (2), and then the pressure in the control chamber (13) is reduced to open the needle valve (8) to form an injection.

Images