A nested double needle valve variable injection rate electronically controlled fuel injector

Abstract

The present application aims at providing a nested double needle valve variable injection law electric control injector, belonging to the field of internal combustion engine. The injector comprises a fastening cap, an upper fastening cap and a lower fastening cap, the fastening cap is fixed outside the upper fastening cap, the upper end of the lower fastening cap is fixed to the lower end of the lower fastening cap, the upper fastening cap is sequentially provided with a pressure accumulation cavity wall, a control valve fastening block, an upper quantity orifice plate and a middle quantity orifice plate from top to bottom, the lower fastening cap is sequentially provided with a lower quantity orifice plate, a double needle valve and a lift change valve control cavity module and a nozzle from top to bottom, and the control valve fastening block is provided with a double electromagnetic valve control assembly. The present application realizes accurate control of three control cavities through two electromagnetic valves, the maximum lift change function of the inner needle valve can change the fuel flow area between the inner needle valve and the valve seat, the inner and outer double needle valve switching opening function can change the type of the injection hole, indirectly affects the injection law through the difference of the injection hole type, and is beneficial to improving the combustion in the cylinder of the diesel engine and reducing the emission pollutants.

Description

Technical Field

[0001] The present invention relates to an internal combustion engine, specifically to a fuel injector for an internal combustion engine. Background Technology

[0002] Electronic fuel injectors offer numerous technological advantages. They can precisely control the amount of fuel injected, making fuel injection more accurate and thus improving fuel efficiency; the injection timing can be precisely adjusted to optimize the combustion process; they can also achieve multiple injections, reducing pollutant emissions; and they have a fast response speed, quickly adjusting injection parameters according to engine operating conditions to enhance engine power performance and stability.

[0003] Currently, variable adjustment of fuel injection patterns is mainly achieved by changing fuel pressure. Specifically, this is done by adding a fuel booster valve to the fuel supply line, which is activated when needed to change the fuel supply pressure and thus alter the injection pattern curve. However, this approach often requires a large return oil volume to drive the oil pressure regulating components and adjust the fuel pressure within the injection unit in order to ensure the effective operation of the hydraulic system. This significantly impacts the efficiency and economy of the entire fuel injection system. Summary of the Invention

[0004] The purpose of this invention is to provide a nested dual needle valve variable injection pattern electronically controlled fuel injector that can adapt to more complex in-cylinder fuel supply and spraying requirements of diesel engines and meet more actual working conditions of internal combustion engines.

[0005] The objective of this invention is achieved as follows:

[0006] This invention discloses a nested dual-needle valve variable injection pattern electronically controlled fuel injector, characterized by: a fastening cap, an upper fastening cap, and a lower fastening cap. The fastening cap is fixed to the outside of the upper fastening cap, and the upper end of the lower fastening cap is fixed to the lower end of the lower fastening cap. The upper fastening cap contains, from top to bottom, a pressure accumulator wall, a control valve fastening block, an upper orifice plate, and a middle orifice plate. The lower fastening cap contains, from top to bottom, a lower orifice plate, a dual-needle valve and a lift-changing valve control chamber module, and a nozzle. The control valve fastening block contains a dual solenoid valve control assembly. The pressure accumulator wall contains a pressure accumulator chamber. The control valve fastening block contains a left fuel inlet and a right fuel inlet. The middle orifice plate contains an orifice plate pressure accumulator chamber. The left fuel inlet connects to both the pressure accumulator chamber and the orifice plate pressure accumulator chamber, and the right fuel inlet connects to the pressure accumulator chamber. The fastening cap contains an interface connecting to the pressure accumulator chamber.

[0007] The present invention may also include:

[0008] 1. The dual solenoid valve control assembly includes a control valve housing and an upper solenoid valve, a lower solenoid valve, and a nested spool valve assembly within the control valve housing. The upper solenoid valve includes an upper solenoid valve armature, a control valve core, and an upper solenoid valve return spring. The lower solenoid valve includes a lower solenoid valve stem, a lower solenoid valve armature, and a lower solenoid valve return spring. The control valve core and the lower solenoid valve stem are arranged opposite to each other. The nested spool valve assembly is located between the control valve core and the lower solenoid valve stem. The upper solenoid valve armature is installed on the top of the control valve core, and the lower solenoid valve armature is installed on the bottom of the lower solenoid valve stem. The control valve core is fitted with an upper solenoid valve return spring, and the lower solenoid valve stem is fitted with a lower solenoid valve return spring. The control valve housing contains a first flange, a second flange, and a third flange. The upper and lower ends of the upper solenoid valve return spring are the first flange and the control valve core, respectively, while the upper and lower ends of the lower solenoid valve return spring are the second and third flanges, respectively. The nested spool valve assembly includes a nested spool valve housing and a nested spool valve inner... The nested spool valve housing is located between the control valve spool and the lower solenoid valve stem. The nested spool valve inner core is located inside the nested spool valve housing. The nested spool valve inner core and the control valve spool form a return oil flow channel for the nested spool valve inner core. The nested spool valve inner core, control valve spool, and nested spool valve housing form the intermediate cavity of the nested spool valve. The nested spool valve inner core and the lower nested spool valve housing form the bottom oil discharge through hole of the nested spool valve. The control valve spool and the control valve housing respectively form the upper chamber, middle chamber, and lower chamber of the control valve spool. The valve core is equipped with an internal oil passage for control. The internal oil passage of the control valve core is connected to the middle chamber of the control valve core and the return oil flow channel of the inner core of the nested spool valve. The return oil flow channel of the inner core of the nested spool valve is connected to the middle chamber of the nested spool valve. The upper solenoid valve and the housing of the control valve form an upper return oil chamber, and the lower solenoid valve and the housing of the control valve form a lower return oil chamber. The housing of the control valve is equipped with an upper return oil hole that communicates with the upper return oil chamber and a lower return oil hole that communicates with the lower return oil chamber. The oil discharge through hole at the bottom of the nested spool valve is connected to the lower return oil chamber. The housing of the nested spool valve is machined with an oil groove for the valve stem of the lower solenoid valve.

[0009] 2. The dual-needle valve and lift-change valve control chamber module includes a lift-change valve fastening block, an upper fastening block for the inner needle valve, a lower fastening block for the inner needle valve, a lift-change valve, an inner needle valve, and an outer needle valve. The outer needle valve is located inside the nozzle, and the main body of the inner needle valve is located inside the outer needle valve. The upper end of the inner needle valve passes through the lower fastening block and is located inside the upper fastening block. The upper part of the lift-change valve is located inside the lift-change valve fastening block, and the lower part of the lift-change valve is located inside the upper fastening block. A lift-change valve return spring is fitted on the upper part of the lift-change valve, and a return spring is fitted on the upper part of the inner needle valve. The inner needle valve is located above the outer needle valve. Some valves are fitted with external needle valve return springs. The location of the return spring of the lift-change valve forms the control chamber of the lift-change valve, the location of the return spring of the internal needle valve forms the control chamber of the internal needle valve, and the location of the return spring of the external needle valve forms the control chamber of the external needle valve. The control chamber of the lift-change valve is connected to the middle chamber of the control valve core through the return oil throttle hole of the lift-change valve on the lower orifice plate, and the control chamber of the lift-change valve is connected to the accumulator chamber of the orifice plate through the inlet oil throttle hole of the control chamber of the lift-change valve. The upper fastening block of the internal needle valve is respectively provided with the inlet oil passage and the outlet oil passage of the control chamber of the external needle valve. The inlet oil passage of the control chamber of the external needle valve is connected to the accumulator chamber of the orifice plate. The control chamber has two oil passages: one for the outer needle valve and the other for the inner needle valve. The outer needle valve control chamber's inlet oil passage connects to the outer needle valve control chamber via an inlet throttle orifice. A third drain hole for the outer needle valve control chamber is located in the lower fastening block, connecting to the outer needle valve control chamber's outlet throttle orifice. The lift-change valve fastening block contains both an inlet oil passage and a return oil passage for the inner needle valve control chamber. An oil reservoir for the lift-change valve is formed between the lift-change valve and its fastening block. The lift-up valve has an inner needle valve control chamber with an inlet throttling orifice. The inlet oil circuit of the inner needle valve control chamber is connected to the orifice plate accumulator chamber and the lift-up valve oil reservoir. The inlet throttling orifice of the inner needle valve control chamber is connected to the lift-up valve oil reservoir and the inner needle valve control chamber. The return oil circuit of the inner needle valve control chamber is connected to the lift-up valve oil reservoir and the lower chamber of the control valve core. An outer needle valve oil reservoir is formed between the outer needle valve and the nozzle. The outer needle valve oil reservoir is connected to the orifice plate accumulator chamber and the right fuel supply circuit. An oil reservoir is formed between the inner needle valve and the outer needle valve. A fuel connection channel is opened in the outer needle valve, which connects the outer needle valve oil reservoir and the oil reservoir.

[0010] 3. During the injection preparation stage, the coils of the upper and lower solenoid valves are not energized, resulting in no electromagnetic force. Under the action of the lower solenoid valve's return spring, the upper chamber of the control valve core rests on the lower end face of the second flange of the control valve housing. The entire control valve core rests on the upper end face of the inner needle valve control chamber under the action of the upper solenoid valve's return spring, and the control slide valve module is in a fully locked state. High-pressure fuel enters the orifice plate accumulator chamber through the left fuel inlet circuit, and then splits into two paths: one path enters the fuel storage chamber through the left fuel inlet circuit to complete fuel supply; the other path enters the outer needle valve control chamber through the outer needle valve control chamber inlet circuit to complete fuel supply to the outer needle valve control chamber. At this time, the upper chamber of the control valve core is closed, and the high-pressure fuel in the outer needle valve control chamber, in conjunction with the outer needle valve's return spring, controls the injection. The external needle valve applies downward pressure, causing it to seat and seal the nozzle. One oil path flows into the internal needle valve control chamber via the inlet oil path. At this time, the lower chamber of the control valve core is closed. High-pressure fuel, in conjunction with the internal needle valve return spring, applies downward pressure to the internal needle valve, causing it to seat and seal the nozzle. Another oil path enters the lift-change valve control chamber via the inlet oil path and the lift-change valve control chamber inlet throttle orifice. At this time, the control spool valve module is closed. High-pressure fuel, in conjunction with the lift-change valve return spring, applies downward pressure to the lift-change valve, causing it to seat on the upper end face of the fastening block flange of the internal needle valve.

[0011] 4. When the external needle valve injects independently, the lower solenoid valve coil is energized, while the upper solenoid valve coil remains de-energized. At this time, the armature of the lower solenoid valve is affected by electromagnetic force, causing the valve stem of the lower solenoid valve to move downward. The entire control valve core moves downward simultaneously under the action of the return spring of the upper solenoid valve. The upper chamber of the control valve core is connected to the upper return oil chamber. The high-pressure fuel in the control chamber of the external needle valve reaches the upper chamber of the control valve core through the oil outlet of the control chamber of the external needle valve, and then completes the oil discharge through the upper return oil hole. At this time, the downward pressure of the high-pressure fuel in the control chamber of the external needle valve on the external needle valve is reduced. When the pressure is low, the high-pressure fuel at the bottom of the oil chamber causes the outer needle valve to lift, and the outer needle valve nozzle begins to inject fuel. When the lower solenoid valve is de-energized, the lower solenoid valve stem, due to the action of the lower solenoid valve return spring, returns to the lower end face of the second flange of the control valve housing, and drives the control valve core to move up to its original position. At this time, the upper chamber of the control valve core is sealed again by the upper end of the control valve core, the oil leakage process ends, the high-pressure fuel refills the control chamber of the outer needle valve, and the outer needle valve returns to its seat with the outer needle valve return spring, the outer needle valve nozzle closes, and the fuel injection process ends.

[0012] 5. When the inner needle valve injects independently, the upper solenoid valve coil is energized, while the lower solenoid valve remains de-energized. At this time, the armature of the upper solenoid valve is affected by electromagnetic force, causing the entire control valve core to move upward. The seal of the lower chamber of the control valve core is released, and the return oil passage of the inner needle valve control chamber in the control valve housing is connected to the lower return oil chamber. The high-pressure fuel in the inner needle valve control chamber reaches the lower return oil chamber through the return oil passage of the inner needle valve control chamber, and then completes the oil discharge through the lower return oil hole. At this time, the downward pressure of the high-pressure fuel in the inner needle valve control chamber on the inner needle valve is weakened, and the pressure of the high-pressure fuel in the oil collection chamber overcomes the pressure of the inner needle valve. The downward pressure generated by the needle valve return spring causes the inner needle valve to lift, and fuel flows through the pressure chamber to the inner needle valve injection hole, starting injection. At this time, the lift of the inner needle valve is limited by the bottom surface of the lift conversion valve. When the upper solenoid valve is de-energized, the control valve core as a whole, due to the action of the upper solenoid valve return spring, causes the lower section of the control valve core to reseat on the upper end face of the nested slide valve assembly. The lower return oil chamber is sealed again by the lower section of the control valve core, the oil leakage process ends, and high-pressure fuel refills the inner needle valve control chamber. With the help of the inner needle valve return spring, the inner needle valve sits down, the inner needle valve injection hole is closed, and the fuel injection process ends.

[0013] 6. When the inner needle valve is in boot-shaped injection mode, the upper solenoid valve coil is energized before the lower solenoid valve coil. The armature of the upper solenoid valve is affected by electromagnetic force, which drives the control valve core to move upward. At this time, the control slide valve module is closed, and the lower chamber of the control valve core is unsealed. The inner needle valve starts to inject fuel in its independent injection mode. At this time, the upper limit of the inner needle valve lift is limited by the lower end face of the lift conversion valve. After the inner needle valve reaches the lift limit, the lower solenoid valve coil is energized. The armature of the lower solenoid valve drives the lower solenoid valve stem and the nested slide valve shell to move downward. At this time, the inner core of the nested slide valve is connected to the lower return oil chamber. The high-pressure fuel located in the control chamber of the lift conversion valve flows to the lower return oil chamber through the oil inlet of the control chamber of the lift conversion valve, and then completes the oil discharge through the lower return oil hole. The lift conversion valve moves upward under the action of the inner needle valve and reaches the lower end face of the lower metering plate, completing the lift conversion of the inner needle valve.

[0014] The advantages of this invention are as follows: The nested dual-needle valve variable injection pattern electronically controlled injector of this invention achieves precise control of three control chambers (i.e., the inner needle valve control chamber, the outer needle valve control chamber, and the lift-changing valve control chamber) through two solenoid valves (i.e., the upper solenoid valve and the lower solenoid valve). The maximum lift switching function of the inner needle valve can change the fuel flow area between it and the valve seat; the switching opening function of the inner and outer dual needle valves can change the type of injection orifice (i.e., the inner needle valve injection orifice and the outer needle valve injection orifice). The different injection orifice types indirectly affect the injection pattern. Both can achieve flexible and variable injection pattern curve shapes to meet a wider range of operating conditions, which is beneficial for improving combustion in the diesel engine cylinder and reducing pollutant emissions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the dual electromagnetic control component structure;

[0017] Figure 3 This is a schematic diagram of the control valve slide valve assembly.

[0018] Figure 4 This is a schematic diagram of the control chamber module for a dual needle valve and a lift-change valve. Detailed Implementation

[0019] The invention will now be described in more detail with reference to the accompanying drawings:

[0020] Combination Figure 1-4 The present invention relates to a nested double needle valve variable injection pattern electronically controlled fuel injector, comprising an interface 1, a tightening cap 2, a pressure accumulator chamber wall 3, a control valve fastening block 4, a left fuel inlet passage 5, a lift-change valve control chamber inlet passage 6, a lift-change valve return passage 7, a metering plate pressure accumulator chamber 8, an upper metering plate 9, a lift-change valve control chamber inlet throttling orifice 10, a metering plate 11, a lower metering plate 12, a lower tightening cap 13, and a nozzle left fuel supply passage. Composed of: 14. Nozzle; 15. Inner needle valve; 16. Pressure chamber; 17. Fastening cap; 18. Accumulation chamber; 19. Dual solenoid valve control assembly; 20. Control slide valve module; 21. Right fuel supply circuit; 22. Inner needle valve control chamber return circuit; 23. Lower metering orifice plate lift change valve return throttle orifice; 24. Dual needle valve and lift change valve control chamber module; 25. Outer needle valve; 26. Oil collection chamber; 27. Outer needle valve nozzle; 28. Inner needle valve nozzle; and 29.

[0021] The accumulator chamber wall 3, dual solenoid valve control assembly 20, control valve fastening block 4, upper orifice plate 9, orifice plate 11, lower orifice plate 12, dual needle valve and lift-changing valve control chamber module 25, and nozzle 15 are installed from top to bottom and connected by locating pins. The control valve fastening block 4 and dual solenoid valve control assembly 20 are connected as a single unit by threads. Fastening caps 18, upper and lower are all threaded together. The inner needle valve 16 is nested within the outer needle valve 26 and placed in the nozzle 15. The diameter of the inner needle valve 16's tail end is reduced, while the inner diameter of the outer needle valve's tail section 24 is increased, forming an oil-collecting chamber 27 with the nozzle 15. The lower conical surface of the inner needle valve 16 seals with the concave surface machined at the bottom of the nozzle 15 to form a pressure chamber 17. The nozzle 15 has an outer needle valve nozzle hole 28 machined at its tail end and an inner needle valve nozzle hole 29 machined at its bottom end.

[0022] During the high-pressure fuel supply process, fuel first flows into the accumulator chamber 19 through interface 1, and then splits into two paths. One path flows into the oil holding chamber 27 through interface 22 to complete the fuel supply; the other path enters the upper metering plate accumulator chamber 8 through the left fuel inlet passage 5, and then reaches the oil holding chamber 27 through the left fuel supply passage 14 of the nozzle to complete the fuel supply. The other three fuel paths leading out from interface 8 supply fuel to the control chambers of various valves in the pilot control module 25.

[0023] The dual solenoid valve control assembly 28 includes an upper solenoid valve 30, a first flange 31 of the control valve housing, an upper solenoid valve return spring 32, a control valve housing 33, a central chamber 34 of the control valve core, a nested spool valve assembly 35, an internal oil passage 36 of the control valve core, a control valve core 37, a second flange 38 of the control valve housing, a third flange 39 of the control valve housing, a lower solenoid valve stem 40, an upper solenoid valve armature 41, an upper return oil chamber 42, an upper return oil hole 43, an upper chamber 44 of the control valve core, a lower chamber 45 of the control valve core, a lower return oil chamber 46, a lower return oil hole 47, a lower solenoid valve stem oil groove 48, a lower solenoid valve return spring 49, a lower solenoid valve armature 50, a lower solenoid valve 51, and a lower return oil chamber 52.

[0024] The upper solenoid valve 30 consists of an upper solenoid valve armature 41, a control valve core 37, an upper solenoid valve return spring 32, and a nested slide valve assembly 35. The lower solenoid valve 51 consists of a lower solenoid valve stem 40, a lower solenoid valve armature 50, and a lower solenoid valve return spring 49. The upper solenoid valve 30 and the lower solenoid valve 51 are symmetrically installed in the control valve housing 33.

[0025] The upper part of the control valve housing 33 has a first flange 31, and the lower end face of which is fitted with an upper solenoid valve return spring 32. The lower part of the control valve housing 33 has a second flange 38 and a third flange 39. The lower solenoid valve return spring 49 is placed between the middle flange of the nested spool valve housing 57 and the third flange 39. The nested spool valve housing 57 has a lower solenoid valve stem oil groove 48. The upper solenoid valve 30 and the lower solenoid valve 51 are sealed with the control valve housing 33 to form two sealed chambers, an upper return oil chamber 42 and a lower return oil chamber 52, respectively, in which upper return oil holes 43 and lower return oil holes 47 are machined. The middle recess of the control valve core 37 cooperates with the control valve housing 33 to form a middle chamber 34 of the control valve core.

[0026] The nested spool valve assembly 35 includes a nested spool valve inner core oil return channel 53, a nested spool valve inner core bottom oil drain hole 54, a nested spool valve intermediate cavity 55, a nested spool valve inner core 56, and a nested spool valve outer shell 57. The nested spool valve 56 and the nested spool valve outer shell 57 form a seal with the top groove. The nested spool valve outer shell 57 has a nested spool valve inner core bottom oil drain hole 54 machined in it to prevent oil trapping during the operation of the nested spool valve 56.

[0027] The dual needle valve and lift-change valve control chamber module 25 includes a lift-change valve control chamber 58, an inner needle valve control chamber oil inlet passage 59, a lift-change valve fastening block 60, an outer needle valve control chamber oil inlet passage 61, an inner needle valve control chamber oil inlet throttle orifice 62, an inner needle valve control chamber 63, an inner needle valve return spring 64, an outer needle valve control chamber oil inlet throttle orifice 65, an outer needle valve control chamber 66, a lift-change valve return spring 67, an inner needle valve upper fastening block 68, a lift-change valve 69, an inner needle valve upper fastening block flange 70, an inner needle valve lower fastening block 71, an outer needle valve control chamber oil outlet passage 72, an outer needle valve control chamber oil outlet throttle orifice 73, an outer needle valve control chamber third drain hole 74, and an outer needle valve return spring 75.

[0028] An oil inlet passage 59 for the inner needle valve control chamber is machined in the lift-change valve fastening block 60, and the lift-change valve return spring 67 is placed in the lift-change valve control chamber 58. An oil outlet passage 72 for the outer needle valve control chamber is machined in the inner needle valve upper fastening block 68. The inner needle valve upper fastening block 68, together with the lift-change valve 69 and the inner needle valve 16, constitutes the inner needle valve control chamber 63. An inner needle valve upper fastening block flange 70 is machined in the inner needle valve upper fastening block 68 to house the inner needle valve return spring 64 and the lift-change valve 69. An oil outlet passage 23 for the inner needle valve control chamber and an oil inlet throttling orifice 62 for the inner needle valve control chamber are machined in the lift-change valve 69. The inner needle valve lower fastening block 71 is machined with an oil outlet throttling hole 73, an oil inlet throttling hole 65, and an outer needle valve return spring 75. It, together with the outer needle valve 15 and the nozzle 15, constitutes the outer needle valve control chamber 66. The outer needle valve return spring 75 is placed in the outer needle valve control chamber 66.

[0029] The nested dual-needle valve and dual-lift variable injection pattern electronically controlled fuel injector of this invention can realize four basic injection modes: independent injection by the outer needle valve, small lift of the inner needle valve, large lift of the inner needle valve, and shoe-shaped injection by the inner needle valve. Different multi-injection modes can also be achieved through combinations of these four basic injection modes. The working process of the four basic injection modes of this fuel injector is as follows:

[0030] During the injector injection preparation stage, the coils of the upper solenoid valve 30 and the lower solenoid valve 51 are not energized and there is no electromagnetic force. Therefore, the upper chamber 44 of the control valve core is seated on the lower end face of the second flange 38 of the control valve housing under the action of the lower solenoid valve return spring 49, and the entire control valve core 37 is seated on the upper end face of the inner needle valve control chamber 63 under the action of the upper solenoid valve return spring 32. The control slide valve module 21 is in a fully locked state. High-pressure fuel enters the orifice plate accumulator chamber 8 through the left fuel inlet passage 5, and then splits into four paths. One path enters the oil holding chamber 27 through the left fuel inlet passage 5, completing the fuel supply; another path enters the outer needle valve control chamber 66 through the outer needle valve control chamber inlet passage 61, at which time the upper chamber 44 of the control valve core is closed, and the high-pressure fuel in the outer needle valve control chamber 66, together with the outer needle valve return spring 75, applies downward pressure to the outer needle valve 26, causing the outer needle valve 26 to sit and complete the sealing of the outer needle valve nozzle 28; the third path flows into the inner needle valve control chamber 63 through the inner needle valve control chamber inlet passage 59, at which time the lower chamber of the control valve core... When 45 is in a closed state, high-pressure fuel in the inner needle valve control chamber 63, in conjunction with the inner needle valve return spring 64, applies downward pressure to the inner needle valve 16, causing the inner needle valve 16 to sit and complete the sealing of the inner needle valve injection hole 29; one path enters the lift-change valve control chamber 58 through the lift-change valve control chamber inlet oil passage 6 and the lift-change valve control chamber inlet throttle hole 10. At this time, the control slide valve module 21 is closed, and high-pressure fuel in the lift-change valve control chamber 58, in conjunction with the lift-change valve return spring 67, applies downward pressure to the lift-change valve 69, causing the lift-change valve 69 to sit on the upper end face of the fastening block flange 70 of the inner needle valve.

[0031] When the injector is in the injection mode of independent injection of the external needle valve, the coil of the lower solenoid valve 51 is energized, while the coil of the upper solenoid valve 30 remains de-energized. At this time, the armature 50 of the lower solenoid valve is affected by electromagnetic force, which drives the valve stem 40 of the lower solenoid valve to move downward. The entire control valve core 37 moves downward at the same time under the action of the return spring 32 of the upper solenoid valve. The upper chamber 44 of the control valve core is thus connected to the upper return oil chamber 42. The high-pressure fuel in the control chamber 66 of the external needle valve reaches the upper chamber 44 of the control valve core through the oil outlet 72 of the control chamber of the external needle valve, and then completes the oil discharge through the upper return oil hole 43. At this time, the downward pressure of the high-pressure fuel in the outer needle valve control chamber 66 on the outer needle valve 26 decreases, and the high-pressure fuel pressure at the bottom of the oil filling chamber 27 causes the outer needle valve 26 to lift, and the outer needle valve nozzle 28 begins to inject fuel. When the lower solenoid valve 51 is de-energized, the lower solenoid valve stem 40, due to the action of the lower solenoid valve return spring 49, re-sits on the lower end face of the second flange 38 of the control valve housing, and drives the control valve core 37 to move upward to its original position. At this time, the upper chamber 44 of the control valve core is re-sealed by the upper end of the control valve core 47, the oil draining process ends, and the high-pressure fuel refills the outer needle valve control chamber 66. With the help of the outer needle valve return spring 75, the outer needle valve 26 sits down, the outer needle valve nozzle 28 closes, and the fuel injection process ends. Throughout the process, the control slide valve module 21 is in a closed state. To prevent oil trapping in the inclined groove of the outer needle valve control chamber 66, a third oil drain hole 74 for the outer needle valve control chamber is opened in its top inclined groove.

[0032] When the injector is in the injection mode of independent injection of the inner needle valve, the coil of the upper solenoid valve 30 is energized and the lower solenoid valve 51 remains de-energized. At this time, the armature 41 of the upper solenoid valve is affected by electromagnetic force, which drives the entire control valve core 37 to move upward. The seal of the lower chamber 45 of the control valve core is released, and the return oil passage 23 of the inner needle valve control chamber in the control valve housing 33 is connected to the lower return oil chamber 46. The high-pressure fuel in the inner needle valve control chamber 63 reaches the lower return oil chamber 46 through the return oil passage 23 of the inner needle valve control chamber, and then completes the oil discharge through the lower return oil hole 47. At this time, the downward pressure of the high-pressure fuel in the inner needle valve control chamber 63 on the inner needle valve 16 is reduced, and the pressure of the high-pressure fuel in the oil filling chamber 27 overcomes the downward pressure generated by the inner needle valve return spring 64, causing the inner needle valve 16 to lift. The fuel flows through the pressure chamber 17 to the inner needle valve injection hole 29 and begins to be injected. At this time, the lift of the inner needle valve is limited by the bottom surface of the lift conversion valve 69. When the upper solenoid valve 30 is de-energized, the control valve core 37 is repositioned on the upper end face of the nested slide valve assembly 35 due to the action of the upper solenoid valve return spring 32. The lower return oil chamber 46 is sealed again by the lower section of the control valve core 37, the oil draining process ends, the high-pressure fuel refills the inner needle valve control chamber 63, and the inner needle valve 16 is repositioned in conjunction with the inner needle valve return spring 64, the inner needle valve injection hole 29 is closed, and the fuel injection process ends. Under this condition, the inner core 56 of the nested slide valve will undergo relative displacement with the nested slide valve assembly 35, but the displacement is limited, and the intermediate cavity 55 of the nested slide valve is always sealed by the nested slide valve assembly 35 during this process.

[0033] When the inner needle valve is in the boot-shaped injection mode, the coil of the upper solenoid valve 30 is energized before the coil of the lower solenoid valve 51. The armature 41 of the upper solenoid valve is affected by electromagnetic force, which drives the entire control valve core 37 to move upward. At this time, the control slide valve module 21 is closed, and the lower chamber 45 of the control valve core is released. The inner needle valve 16 starts to inject oil in the same injection mode as its independent injection. At this time, the upper limit of the lift of the inner needle valve 16 is limited by the lower end face of the lift conversion valve 69. After the inner needle valve 16 reaches its lift limit, the coil of the lower solenoid valve 51 is energized. The armature 50 of the lower solenoid valve drives the valve stem 40 of the lower solenoid valve and the nested slide valve housing 57 to move downward. At this time, the inner core 56 of the nested slide valve is connected to the lower return oil chamber 46. The high-pressure fuel located in the lift change valve control chamber 58 flows to the lower return oil chamber 46 through the oil inlet passage 6 of the lift change valve control chamber, and then completes the oil discharge through the lower return oil hole 47. The lift change valve 69 moves upward under the action of the inner needle valve 16 and reaches the lower end face of the lower metering orifice plate 12, completing the lift change of the inner needle valve 16.

[0034] With independent injection from the outer needle valve, small-lift injection from the inner needle valve, large-lift injection from the inner needle valve, and shoe-shaped injection from the inner needle valve, this injector can also achieve multiple injection modes such as "independent injection from the outer needle valve - shoe-shaped injection from the inner needle valve" to meet the fuel spray requirements of more diesel engines under actual operating conditions.

Claims

1. A nested dual-needle valve variable injection pattern electronically controlled fuel injector, characterized in that: The fastening cap is fixed outside the upper tightening cap, the upper end of the lower tightening cap is fixed at the lower end of the lower tightening cap, and the upper tightening cap is sequentially provided with a pressure accumulation cavity wall, a control valve fastening block, an upper flow hole plate and a middle flow hole plate from top to bottom; the lower tightening cap is sequentially provided with a lower flow hole plate, a double needle valve and a lift change valve control cavity module, and a nozzle from top to bottom; the control valve fastening block is provided with a double electromagnetic valve control assembly; the pressure accumulation cavity is arranged in the pressure accumulation cavity wall; the control valve fastening block is respectively provided with a fuel left oil inlet oil way and a fuel right oil inlet oil way; the flow hole plate is provided with a flow hole plate pressure accumulation cavity; the fuel left oil inlet oil way is respectively communicated with the pressure accumulation cavity and the flow hole plate pressure accumulation cavity; the fuel right oil inlet oil way is communicated with the pressure accumulation cavity; and the fastening cap is provided with an interface communicated with the pressure accumulation cavity. The double electromagnetic valve control assembly comprises a control valve housing and an upper electromagnetic valve, a lower electromagnetic valve and a nested spool valve assembly in the control valve housing; the upper electromagnetic valve comprises an upper electromagnetic valve armature, a control valve core, an upper electromagnetic valve return spring; the lower electromagnetic valve comprises a lower electromagnetic valve valve rod, a lower electromagnetic valve armature and a lower electromagnetic valve return spring; the control valve core and the lower electromagnetic valve valve rod are oppositely arranged; the nested spool valve assembly is located between the control valve core and the lower electromagnetic valve valve rod; the top of the control valve core is provided with the upper electromagnetic valve armature; the bottom of the lower electromagnetic valve valve rod is provided with the lower electromagnetic valve armature; the control valve core is sleeved with the upper electromagnetic valve return spring; the lower electromagnetic valve valve rod is sleeved with the lower electromagnetic valve return spring; the control valve housing is provided with a control valve housing first flange, a control valve housing second flange and a control valve housing third flange; the upper and lower ends of the upper electromagnetic valve return spring are respectively the control valve housing first flange and the control valve core; the upper and lower ends of the lower electromagnetic valve return spring are respectively the control valve housing second flange and the control valve housing third flange; the nested spool valve assembly comprises a nested spool valve housing and a nested spool valve inner core; the nested spool valve housing is located between the control valve core and the lower electromagnetic valve valve rod; the nested spool valve inner core is located in the nested spool valve housing; an oil return flow channel of the nested spool valve inner core is formed between the nested spool valve inner core and the control valve core; a nested spool valve intermediate cavity is formed between the nested spool valve inner core, the control valve core and the nested spool valve housing; a nested spool valve bottom oil discharge through hole is formed between the nested spool valve inner core and the lower nested spool valve housing; a control valve core upper cavity, a control valve core middle cavity and a control valve core lower cavity are respectively formed between the control valve core and the control valve housing; a control valve core internal oil way is arranged in the control valve core; the control valve core internal oil way is respectively communicated with the control valve core middle cavity and the nested spool valve inner core oil return flow channel; the nested spool valve inner core oil return flow channel is communicated with the nested spool valve intermediate cavity; an upper oil return cavity is formed between the upper electromagnetic valve and the control valve housing; a lower oil return cavity is formed between the lower electromagnetic valve and the control valve housing; an upper oil return hole communicated with the upper oil return cavity and a lower oil return hole communicated with the lower oil return cavity are arranged in the control valve housing; the nested spool valve bottom oil discharge through hole is communicated with the lower oil return cavity; a lower electromagnetic valve valve rod oil groove is formed in the nested spool valve housing.

2. The nested dual needle valve variable injection rate electronically controlled injector according to claim 1, characterized in that: The double needle valve and lift conversion valve control cavity module comprises a lift conversion valve fastening block, an inner needle valve upper fastening block, an inner needle valve lower fastening block, a lift conversion valve, an inner needle valve and an outer needle valve, wherein the outer needle valve is located in a nozzle, the main body of the inner needle valve is located in the outer needle valve, the upper end of the inner needle valve passes through the inner needle valve lower fastening block and is located in the inner needle valve upper fastening block, the upper part of the lift conversion valve is located in the lift conversion valve fastening block, the lower part of the lift conversion valve is located in the inner needle valve upper fastening block, the upper part of the lift conversion valve is sleeved with a lift conversion valve return spring, the upper part of the inner needle valve is sleeved with an inner needle valve return spring, the part of the inner needle valve located in the upper part of the outer needle valve is sleeved with an outer needle valve return spring, the position of the lift conversion valve return spring forms a lift conversion valve control cavity, the position of the inner needle valve return spring forms an inner needle valve control cavity, and the position of the outer needle valve return spring forms an outer needle valve control cavity; the lift conversion valve control cavity is connected with the middle cavity of the control valve core through a lift conversion valve oil return throttle hole and a lower amount hole plate; the lift conversion valve control cavity is connected with a flow hole plate pressure accumulation cavity through a lift conversion valve control cavity oil inlet throttle hole; an outer needle valve control cavity oil inlet oil way and an outer needle valve control cavity oil outlet oil way are arranged in the inner needle valve upper fastening block, the outer needle valve control cavity oil inlet oil way is connected with the flow hole plate pressure accumulation cavity, the outer needle valve control cavity oil inlet oil way is connected with the outer needle valve control cavity through an outer needle valve control cavity oil inlet throttle hole, the outer needle valve control cavity oil outlet oil way is connected with the upper cavity of the control valve core, the outer needle valve control cavity oil outlet oil way is connected with the outer needle valve control cavity through an outer needle valve control cavity oil outlet throttle hole, a third outer needle valve control cavity oil outlet hole is arranged in the inner needle valve lower fastening block, and the third outer needle valve control cavity oil outlet hole is connected with the outer needle valve control cavity oil outlet throttle hole; an inner needle valve control cavity oil inlet oil way and an inner needle valve control cavity oil return oil way are arranged in the lift conversion valve fastening block, a lift conversion valve oil tank is formed between the lift conversion valve and the lift conversion valve fastening block, an inner needle valve control cavity oil inlet throttle hole is arranged in the lift conversion valve, the inner needle valve control cavity oil inlet oil way is connected with the flow hole plate pressure accumulation cavity and the lift conversion valve oil tank, the inner needle valve control cavity oil inlet throttle hole is connected with the lift conversion valve oil tank and the inner needle valve control cavity, the inner needle valve control cavity oil return oil way is connected with the lift conversion valve oil tank and the lower cavity of the control valve core; an outer needle valve oil tank is formed between the outer needle valve and the nozzle, the outer needle valve oil tank is connected with the flow hole plate pressure accumulation cavity and a fuel right oil supply oil way, an oil storage cavity is formed between the inner needle valve and the outer needle valve, a fuel communication channel is arranged in the outer needle valve, and the fuel communication channel is connected with the outer needle valve oil tank and the oil storage cavity.

3. The nested dual needle valve variable injection rate electronically controlled injector according to claim 2, characterized in that: In the injection preparation stage, the coils of the upper and lower electromagnetic valves are not electrified, and there is no electromagnetic force, the upper chamber of the control valve core is seated on the lower end surface of the second flange of the control valve housing under the action of the return spring of the lower electromagnetic valve, the whole control valve core is seated on the upper end surface of the inner needle valve control chamber under the action of the return spring of the upper electromagnetic valve, and the control spool module is in a completely closed state; the high-pressure fuel enters the orifice plate pressure accumulation chamber through the fuel left inlet oil way, and then is divided into three paths, one path enters the fuel containing chamber through the fuel left inlet oil way to complete fuel supply, one path enters the outer needle valve control chamber through the outer needle valve control chamber inlet oil way to complete fuel supply to the outer needle valve control chamber, at this time, the upper chamber of the control valve core is closed, the high-pressure fuel in the outer needle valve control chamber applies a downward pressure to the outer needle valve together with the return spring of the outer needle valve to make the outer needle valve seat, and the sealing of the outer needle valve injection hole is completed; one path flows into the inner needle valve control chamber through the inner needle valve control chamber inlet oil way, at this time, the lower chamber of the control valve core is in a closed state, the high-pressure fuel in the inner needle valve control chamber applies a downward pressure to the inner needle valve together with the return spring of the inner needle valve to make the inner needle valve seat, and the sealing of the inner needle valve injection hole is completed; one path enters the lift change valve control chamber through the lift change valve control chamber inlet oil way and the lift change valve control chamber inlet oil throttle hole, at this time, the control spool module is closed, the high-pressure fuel in the lift change valve control chamber applies a downward pressure to the lift change valve together with the return spring of the lift change valve to make the lift change valve seat on the upper end surface of the flange of the inner needle valve upper fastening block.

4. The nested dual needle valve variable injection rate electronically controlled injector according to claim 2, characterized in that: When the outer needle valve is independently injected, the coil of the lower electromagnetic valve is electrified, and the coil of the upper electromagnetic valve remains in a de-energized state, at this time, the armature of the lower electromagnetic valve is driven to move downward under the influence of the electromagnetic force, the whole control valve core is driven to move downward under the action of the return spring of the upper electromagnetic valve, the upper chamber of the control valve core is communicated with the upper oil return chamber, the high-pressure fuel in the outer needle valve control chamber reaches the upper chamber of the control valve core through the outer needle valve control chamber outlet oil way, and then is discharged through the upper oil return hole; at this time, the downward pressure of the high-pressure fuel in the outer needle valve control chamber on the outer needle valve is weakened, the high-pressure fuel at the bottom of the fuel containing chamber lifts the outer needle valve, and the outer needle valve injection hole starts to inject fuel; when the lower electromagnetic valve is de-energized, the valve rod of the lower electromagnetic valve is re-seated on the lower end surface of the second flange of the control valve housing under the action of the return spring of the lower electromagnetic valve, and drives the control valve core to move upward to the original position, at this time, the upper chamber of the control valve core is re-sealed by the upper end of the control valve core, the discharge process is terminated, the high-pressure fuel re-fills the outer needle valve control chamber, the outer needle valve is seated together with the return spring of the outer needle valve, the outer needle valve injection hole is closed, and the fuel injection process is completed.

5. The nested dual needle valve variable injection rate electronically controlled injector according to claim 2, characterized in that: When the inner needle valve is in the independent injection mode, the upper solenoid coil is powered, and the lower solenoid remains in a de-energized state. At this time, the upper solenoid armature is driven to move upward by the electromagnetic force, and the control valve core is driven to move upward as a whole. The lower chamber of the control valve core is unsealed, the inner needle valve control chamber in the control valve housing is communicated with the lower oil return chamber, the high-pressure fuel in the inner needle valve control chamber flows to the lower oil return chamber through the inner needle valve control chamber oil return oil path, and then is discharged through the lower oil return hole. At this time, the downward pressure of the high-pressure fuel in the inner needle valve control chamber on the inner needle valve is weakened, and the high-pressure fuel in the oil storage chamber overcomes the downward pressure generated by the inner needle valve return spring, so that the inner needle valve is lifted, the fuel flows to the inner needle valve injection hole through the pressure chamber, and the injection starts. At this time, the lift of the inner needle valve is limited by the lower bottom surface of the lift conversion valve. When the upper solenoid is de-energized, the control valve core as a whole is seated on the upper end surface of the nested slide valve assembly due to the action of the upper solenoid return spring. The lower oil return chamber is sealed by the lower section of the control valve core again, the discharge process is terminated, the high-pressure fuel fills the inner needle valve control chamber again, and the inner needle valve is seated in cooperation with the inner needle valve return spring. The inner needle valve injection hole is closed, and the injection process is ended.

6. The nested dual needle valve variable injection rate electronically controlled injector of claim 2, wherein: When the inner needle valve is in the boot-shaped injection mode, the upper solenoid coil is powered before the lower solenoid coil. The upper solenoid armature is driven to move upward by the electromagnetic force, and the control valve core is driven to move upward as a whole. At this time, the control slide valve module is closed, the lower chamber of the control valve core is unsealed, and the inner needle valve starts to inject in the same way as in the independent injection mode. At this time, the upper limit of the lift of the inner needle valve is limited by the lower end surface of the lift conversion valve. After the inner needle valve reaches the lift limit, the lower solenoid coil is powered, the lower solenoid armature drives the lower solenoid valve rod and the nested slide valve housing to move downward, and the nested slide valve inner core is communicated with the lower oil return chamber. The high-pressure fuel in the lift conversion valve control chamber flows to the lower oil return chamber through the lift conversion valve control chamber oil inlet oil path, and then is discharged through the lower oil return hole. The lift conversion valve moves upward under the action of the inner needle valve, reaches the lower end surface of the lower amount hole plate, and completes the lift conversion of the inner needle valve.

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