Dual fuel electronically controlled injector and control method

Abstract

The application discloses a dual-fuel electric control injector and a control method. The first layer valve block of the injector is fixedly connected with an upper cover cap and a lower shell, and the first layer to the sixth layer valve blocks and a spray valve block are sequentially embedded in the lower shell. High-pressure fuel and gas enter fuel pressure cavities and gas pressure cavities of the first layer valve block respectively, a double-needle valve assembly is embedded in the spray valve block, the lower end of the double-needle valve assembly penetrates through a lower cavity of the spray valve block and abuts against the inner side surface of the conical bottom of the lower cavity of the spray valve block, and a plurality of inner spray holes and a plurality of outer spray holes are respectively communicated with the lower cavity of the spray valve block. An upper electromagnetic valve assembly and a lower electromagnetic valve assembly are respectively arranged in the third, fourth and fifth layer valve blocks, and control oil paths and control gas paths are respectively arranged in the two sides of the plurality of layer valve blocks. The control method includes single fuel injection and dual-fuel two modes. The application has the advantages of compact structure, realization of the two injection modes of single fuel injection or fuel-gas dual-fuel injection, and improvement of the economic performance and emission performance of the engine.

Description

Technical Field

[0001] This invention relates to an electronically controlled injector for diesel engines, and more particularly to an electronically controlled injector and control method applicable to dual-fuel injection, belonging to the field of dual-fuel engine technology. Background Technology

[0002] With technological advancements, diesel engine development faces severe challenges. Higher diesel engine performance and lower pollutant emissions are the trends in diesel engine development. To improve diesel engine performance, reduce fuel consumption, and simultaneously reduce harmful substances such as particulate matter and carbon monoxide in exhaust, it is necessary to select suitable alternative fuels.

[0003] Natural gas, as a renewable energy source, boasts advantages such as safety, reliability, cleanliness, environmental friendliness, and low cost. Dual-fuel engines combining natural gas and diesel significantly reduce particulate matter emissions, effectively improving overall engine power and fuel economy. Currently, a common approach is to install a gas injection valve externally to the diesel injector to achieve simultaneous in-cylinder injection of fuel and natural gas. However, this structure increases the radial dimension of the injector and raises manufacturing difficulty and cost. Therefore, there is an urgent need for a dual-fuel injector that does not increase radial dimension, enabling flexible and accurate injection of single-fuel fuel or both fuel and gas, thereby improving the overall engine power and fuel economy while reducing pollutant emissions. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-fuel electronically controlled injector and control method that can flexibly switch between single-fuel and dual-fuel injection modes.

[0005] This invention is achieved through the following technical solution:

[0006] A dual-fuel electronically controlled injector includes an upper cap, a lower housing, and several valve blocks, as well as an upper solenoid valve assembly, a lower solenoid valve assembly, a dual needle valve assembly, a control oil circuit, and a control air circuit. The several valve blocks include a first valve block, a second valve block, a third valve block, a fourth valve block, a fifth valve block, a sixth valve block, and an injection valve block. The upper and lower ends of the first valve block are threadedly connected to the lower end of the upper cap and the upper end of the lower housing, respectively. The top of the first valve block abuts against the bottom surface of the threaded hole in the upper cap. The first and second valve blocks abut against each other. The third, fourth, fifth, and sixth valve blocks, along with the bottom injection valve block, are sequentially embedded into the lower housing from top to bottom, with a clearance fit. The conical head at the lower end of the injection valve block protrudes from the lower end of the lower housing. The first valve block has a fuel accumulator chamber and a gas accumulator chamber arranged side-by-side and open at the top. High-pressure fuel with a fuel pressure of 16–22 MPa enters the fuel accumulator chamber of the first valve block through the high-pressure fuel inlet connector and high-pressure fuel inlet hole on one side of the top of the upper fastening cap. High-pressure gas with a gas pressure of 12–15 MPa... Gas enters the gas accumulator chamber of the first-layer valve block through the high-pressure gas inlet connector and high-pressure gas inlet port on the other side of the top of the upper fastening cap; the double needle valve assembly is embedded in the center hole of the injection valve block, and the lower end of the double needle valve assembly passes through the lower cavity of the injection valve block, abutting against the inner side of the conical bottom of the lower cavity of the injection valve block, and blocking several inner and outer injection holes of the lower conical head of the injection valve block, which are respectively connected to the lower cavity of the injection valve block; the bottom of the fuel accumulator chamber passes through the first-layer valve block from top to bottom to the injection... The high-pressure fuel port on one side of the seven-layer valve block is connected to the transverse hole on the outside of the double needle valve assembly; the bottom of the gas accumulator chamber is connected to the lower cavity of the injection valve block through the high-pressure gas port on the other side of the seven-layer valve block, which passes through the first layer valve block to the injection valve block from top to bottom; the upper solenoid valve assembly is located in the third and fourth layer valve blocks, and the lower solenoid valve assembly is located in the fourth and fifth layer valve blocks; the control oil circuit is located in the sixth layer valve block and the injection valve block, and the control air circuit is located on one side of the seven-layer valve block, from the first layer valve block to the injection valve block.

[0007] The objectives of this invention can also be further achieved through the following technical measures.

[0008] Furthermore, the top surfaces of the second, third, fourth, fifth, and sixth valve blocks, as well as the top surface of the nozzle valve block, are each fitted with a sealing ring.

[0009] Furthermore, the upper and lower solenoid valve assemblies have identical structures and are symmetrically arranged vertically. The upper solenoid valve assembly includes an upper electromagnet, an upper armature, an upper valve core, and an upper valve core return spring. The lower solenoid valve assembly includes a lower electromagnet, a lower armature, a lower valve core, and a lower valve core return spring. Both the upper and lower electromagnets are annular. The upper electromagnet is embedded in the countersunk hole at the upper end of the fourth-layer valve block, and the upper valve core return spring is embedded in the central hole of the upper electromagnet. The two ends of the upper valve core return spring abut against the upper armature and the center of the countersunk hole at the upper end of the fourth-layer valve block, respectively. The upper armature located above the upper electromagnet is embedded... The lower electromagnet is inserted into the lower countersunk hole of the third-layer valve block and fixed to the lower end of the upper valve core. The upper end of the upper valve core is embedded in the upper control cavity, which is located at the center of the upper end of the third-layer valve block. The lower electromagnet is embedded in the lower countersunk hole of the fourth-layer valve block, and the lower valve core return spring is embedded in the center hole of the lower electromagnet. The two ends of the lower valve core return spring abut against the lower armature and the center of the lower countersunk hole of the fourth-layer valve block, respectively. The lower armature located below the lower electromagnet is embedded in the upper countersunk hole of the fifth-layer valve block and fixed to the upper end of the lower valve core. The lower end of the lower valve core is embedded in the lower control cavity, which is located at the center of the lower end of the fifth-layer valve block.

[0010] Furthermore, both the upper and lower valve cores are stepped shaft structures. The small end of the stepped shaft of the upper valve core is fixedly connected to the upper armature on the lower side, and the large end of the stepped shaft of the upper valve core is embedded in the upper control cavity. The small end of the stepped shaft of the lower valve core is fixedly connected to the lower armature on the upper side, and the large end of the stepped shaft of the lower valve core is embedded in the lower control cavity.

[0011] Furthermore, the dual-needle valve assembly includes an inner needle valve, an outer needle valve, an inner needle valve control chamber, an outer needle valve control chamber, an outer needle valve lower chamber, an inner needle valve return spring, and an outer needle valve return spring. The outer needle valve is embedded in the central hole of the injection valve block, and the inner needle valve is embedded in the outer needle valve. The lower conical head of the inner needle valve and the lower conical sleeve of the outer needle valve both pass through the lower chamber of the injection valve block and abut against the conical bottom of the lower chamber of the injection valve block. The lower conical head of the inner needle valve blocks several inner spray holes at the lower end of the injection valve block, and the lower conical sleeve of the outer needle valve blocks several outer spray holes at the lower end of the injection valve block. A transverse hole passes through one side of the middle of the outer needle valve and connects with the lower chamber of the outer needle valve. The upper part is connected; the central column at the bottom of the sixth valve block extends into the inner needle valve control chamber, and the two ends of the inner needle valve return spring located in the inner needle valve control chamber abut against the bottom surface of the central column of the sixth valve block and the top of the inner needle valve, respectively; the two ends of the outer needle valve return spring located in the outer needle valve control chamber abut against the bottom of the sixth valve block and the top of the outer needle valve, respectively; the control oil circuit is connected to the high-pressure fuel port on one side of the fifth valve block; the control air circuit passes down from the first valve block through the second, third, fourth, fifth and sixth valve blocks in sequence and leads to the outer needle valve control chamber at the center of the top of the seventh valve block.

[0012] Furthermore, the control oil circuit includes an inlet throttling orifice, a return throttling orifice, and a connecting oil hole for the inner needle valve control chamber, all disposed in the sixth-layer valve block. One end of the inclined connecting oil hole for the inner needle valve control chamber is connected to a high-pressure fuel port on one side of the fifth-layer valve block, and the other end is connected to the upper end of the inlet throttling orifice. The lower end of the inlet throttling orifice for the inner needle valve control chamber passes vertically downward through the central column to the inner needle valve control chamber. The vertically disposed return throttling orifice for the inner needle valve control chamber crosses the center of the sixth-layer valve block, and both ends of the return throttling orifice are connected to the lower control chamber and the inner needle valve control chamber, respectively.

[0013] Furthermore, the control air path includes a control air port, an inlet throttling port for the outer needle valve control chamber, a return throttling port for the outer needle valve control chamber, and a return throttling port for the upper control chamber. The control air port passes sequentially from the bottom of the first valve block downwards through the second, third, fourth, and fifth valve blocks and connects to the upper end of the return throttling port for the outer needle valve control chamber within the sixth valve block. The lower end of the return throttling port for the outer needle valve control chamber leads to the outer needle valve control chamber. The lower end of the return throttling port for the outer needle valve control chamber is also connected to the middle of the high-pressure gas port through the inlet throttling port for the outer needle valve control chamber. The upper end of the control air port is connected to the return throttling port for the upper control chamber, which leads to the top of the upper control chamber, through a horizontal connecting hole.

[0014] Furthermore, the lower center of the lower cavity of the injection valve block is provided with an outer guide sleeve extending vertically upward. The outer circle of the outer guide sleeve is in clearance fit with the inner hole of the outer needle valve. An annular gap A is left between the inner hole of the outer guide sleeve and the outer circle of the inner needle valve. The ratio of the annular gap A to the radius R of the inner hole of the outer guide sleeve is: A / R = 0.19~0.21.

[0015] A control method for a dual-fuel electronically controlled injector includes the following corresponding steps for different operating modes:

[0016] A Single Fuel Injection Mode

[0017] When the lower electromagnet is energized, the sum of the electromagnetic force exerted on the lower armature by the lower electromagnet and the fuel pressure exceeds the preload of the lower valve core return spring. The lower armature drives the lower valve core upward until the top surface of the large end shaft of the lower valve core abuts against the top surface of the lower control chamber, at which point the lower valve core stops moving upward. The pressure at the lower end of the lower control chamber decreases, and the lower control chamber connects with the return oil throttling orifice of the inner needle valve control chamber. Fuel in the inner needle valve control chamber enters the lower part of the lower control chamber through the return oil throttling orifice, further reducing the fuel pressure in the inner needle valve control chamber until the fuel pressure at the lower end of the inner needle valve exceeds the sum of the fuel pressure at the upper end of the inner needle valve and the preload of the inner needle valve return spring. The inner needle valve then moves upward until the return spring is compressed and stops moving upward. The gap between the lower end of the inner needle valve and the inner side of the conical bottom of the lower cavity of the injection valve block increases, and the high-pressure fuel in the lower cavity of the injection valve block is ejected from several internal injection holes through the gap.

[0018] B Dual-fuel injection mode

[0019] When both the upper and lower electromagnets are energized simultaneously, the sum of the electromagnetic force on the upper armature and the gas pressure on its upper end exceeds the preload of the upper valve core return spring. The upper armature causes the upper valve core to move downwards until the top surface of the large end shaft of the upper valve core abuts against the bottom surface of the upper control chamber, at which point the upper valve core stops moving upwards. The pressure at the upper end of the upper control chamber decreases, and the upper control chamber return throttling orifice connects to the control gas port through a horizontal connecting hole. Gas in the outer needle valve control chamber passes sequentially through the outer needle valve control chamber return throttling orifice, the control gas port, and water. The gas enters the upper part of the upper control chamber through the flat connection hole and the return gas throttle hole of the upper control chamber, which further reduces the gas pressure in the control chamber of the outer needle valve until the gas pressure at the lower end of the outer needle valve is greater than the sum of the gas pressure at the upper end of the outer needle valve and the preload force of the outer needle valve return spring. The outer needle valve moves upward until the outer needle valve return spring is compressed and no longer rises. The high-pressure gas in the lower chamber of the injection valve block increases the gap between the lower end of the outer needle valve and the inner side of the conical bottom of the lower chamber of the injection valve block, and the high-pressure gas in the lower chamber of the injection valve block is ejected from several external injection holes.

[0020] At the same time, after the lower electromagnet is energized, the process of single fuel injection mode A is repeated, and the high-pressure fuel in the lower chamber of the injection valve block is injected out from several internal injection holes to complete dual fuel injection.

[0021] This invention features a compact structure, employing symmetrically arranged upper and lower solenoid valve assemblies, and control oil and gas circuits to control the flow of fuel and gas respectively. It also includes a double-needle valve assembly with an interlocking outer and inner needle valve. This design ensures that the radial dimensions of the dual-fuel electronically controlled injector remain unchanged compared to a single-fuel injector, making it suitable for installation on existing diesel engine cylinder heads. This significantly reduces the conversion cost of existing diesel engines to dual-fuel engines and improves conversion efficiency. By using different control methods—activating a single solenoid valve assembly or simultaneously activating both solenoid valve assemblies—it achieves two injection modes: single fuel injection or fuel-gas dual-fuel injection. This allows for flexible switching according to different engine operating conditions, meeting engine power performance requirements and improving engine economy and emissions performance.

[0022] The advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 yes Figure 1 Enlarged view of Part I;

[0025] Figure 3 yes Figure 1 Enlarged view of Part II. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] In the description of this invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" that indicate orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and do not indicate or imply that the device referred to must have a specific orientation.

[0028] like Figure 1 As shown, this embodiment includes an upper cap 1, a lower housing 2, and seven valve blocks 3, as well as an upper solenoid valve assembly 4, a lower solenoid valve assembly 5, a double needle valve assembly 6, a control oil circuit 7, and a control air circuit 8. The seven valve blocks 3 include a first valve block 31, a second valve block 32, a third valve block 33, a fourth valve block 34, a fifth valve block 35, a sixth valve block 36, and an injection valve block 37. The upper and lower ends of the first valve block 31 are threadedly connected to the lower end of the upper cap 1 and the upper end of the lower housing 2, respectively. The top of the first valve block 31 abuts against the bottom surface of the threaded hole 11 of the upper cap. The first valve block 31, the second valve block 32, the third valve block 33, the fourth valve block 34, the fifth valve block 35, the sixth valve block 36, and the bottom injection valve block 37 are sequentially embedded in the lower housing 2 from top to bottom and are in clearance fit with the lower housing 2. The tapered head 371 at the lower end of the stepped, shaft-shaped injection valve block protrudes from the lower end of the lower housing 2. The first-layer valve block 31 has a fuel accumulator chamber 311 and a gas accumulator chamber 312 arranged side by side and open at the top. High-pressure fuel with a pressure of 16-22 MPa enters the fuel accumulator chamber 311 of the first-layer valve block 31 through the high-pressure fuel inlet connector 12 and the high-pressure fuel inlet hole 13 on the left side of the top of the upper fastening cap 1. High-pressure gas with a pressure of 12-15 MPa enters the gas accumulator chamber 312 of the first-layer valve block 31 through the high-pressure gas inlet connector 14 and the high-pressure gas inlet hole 15 on the right side of the top of the upper fastening cap 1. The top surfaces of the second-layer valve block 32, the third-layer valve block 33, the fourth-layer valve block 34, the fifth-layer valve block 35, and the sixth-layer valve block 36, as well as the top surface of the nozzle valve block 37, are each fitted with a sealing ring 38 to prevent fuel and gas from overflowing.

[0029] like Figure 1 and Figure 2 As shown, the upper solenoid valve assembly 4 is disposed in the third layer valve block 33 and the fourth layer valve block 34, and the lower solenoid valve assembly 5 is disposed in the fourth layer valve block 34 and the fifth layer valve block 35.

[0030] The upper solenoid valve assembly 4 and the lower solenoid valve assembly 5 have the same structure and are arranged symmetrically. The upper solenoid valve assembly 4 includes an upper electromagnet 41, an upper armature 42, an upper valve core 43, and an upper valve core return spring 44. The lower solenoid valve assembly 5 includes a lower electromagnet 51, a lower armature 52, a lower valve core 53, and a lower valve core return spring 54. Both the upper electromagnet 41 and the lower electromagnet 51 are annular. The upper electromagnet 41 is embedded in the upper countersunk hole 341 of the fourth-layer valve block. The upper valve core return spring 44 is embedded in the center hole 411 of the upper electromagnet. The two ends of the upper valve core return spring 44 abut against the upper armature 42 and the center of the upper countersunk hole 341 of the fourth-layer valve block, respectively. The upper armature 42, located above the upper electromagnet 41, is embedded in the lower countersunk hole 331 of the third-layer valve block and fixed to the lower end of the upper valve core 43. The upper end of the upper valve core 43 is embedded in the upper control cavity 332, which is located at the upper center of the third-layer valve block 33.

[0031] The lower electromagnet 51 is embedded in the lower countersunk hole 342 of the fourth-layer valve block, and the lower valve core return spring 54 is embedded in the center hole 511 of the lower electromagnet. The two ends of the lower valve core return spring 54 abut against the lower armature 52 and the center of the lower countersunk hole 342 of the fourth-layer valve block, respectively. The lower armature 52, located below the lower electromagnet 51, is embedded in the upper countersunk hole 351 of the fifth-layer valve block and fixed to the upper end of the lower valve core 53. The lower end of the lower valve core 53 is embedded in the lower control cavity 352, which is located at the lower center of the fifth-layer valve block 35.

[0032] Both the upper valve core 43 and the lower valve core 53 have a stepped shaft structure. The small end 431 of the stepped shaft of the upper valve core 43 is fixedly connected to the upper armature 42 on the lower side, and the large end 432 of the stepped shaft of the upper valve core 43 is embedded in the upper control cavity 332. The small end 53 of the stepped shaft of the lower valve core 53 is fixedly connected to the lower armature 52 on the upper side, and the large end 531 of the stepped shaft of the lower valve core 53 is embedded in the lower control cavity 352.

[0033] like Figure 1 and Figure 3 As shown, the dual needle valve assembly 6 is embedded in the central hole 372 of the injection valve block. The lower end of the dual needle valve assembly 6 passes through the lower cavity 373 of the injection valve block and abuts against the inner side of the conical bottom 374 of the lower cavity of the injection valve block, blocking several inner injection holes 376 and several outer injection holes 377 of the lower conical head 371 of the injection valve block. The several inner injection holes 376 and several outer injection holes 377 are respectively connected to the lower cavity 373 of the injection valve block. The bottom of the fuel accumulator chamber 311 is connected to the transverse hole 622 on the outside of the dual needle valve assembly 6 through a high-pressure fuel hole 9 that passes through the left side of the seven valve blocks from the first valve block 31 to the injection valve block 37. The bottom of the gas accumulator chamber 312 is connected to the lower cavity 373 of the injection valve block through a high-pressure gas hole 10 that passes through the right side of the seven valve blocks from the first valve block 31 to the injection valve block 37.

[0034] The dual needle valve assembly 6 includes an inner needle valve 61, an outer needle valve 62, an inner needle valve control chamber 63, an outer needle valve control chamber 64, an outer needle valve lower chamber 65, an inner needle valve return spring 66, and an outer needle valve return spring 67. The outer needle valve 62 is embedded in the central hole 372 of the injection valve block, and the inner needle valve 61 is embedded in the outer needle valve 62. The lower end conical head 611 of the inner needle valve and the lower end conical sleeve 623 of the outer needle valve both pass through the lower chamber 373 of the injection valve block and abut against the conical bottom of the lower chamber 373 of the injection valve block. The lower end conical head 611 of the inner needle valve blocks several inner spray holes 376 at the lower end of the injection valve block 37, and the lower end conical sleeve 623 of the outer needle valve blocks several outer spray holes 377 at the lower end of the injection valve block 37. A transverse hole 622 passes through the middle left side of the outer needle valve 62 and communicates with the upper part of the lower chamber 65 of the outer needle valve, facilitating the delivery of high-pressure fuel in the fuel accumulator chamber 311 to the lower chamber 65 of the outer needle valve through the high-pressure fuel hole 9. The central post 361 at the bottom of the sixth-layer valve block 36 extends into the inner needle valve control chamber 63. The two ends of the inner needle valve return spring 66 located in the inner needle valve control chamber 63 abut against the bottom surface of the central post 361 of the sixth-layer valve block 36 and the top surface of the inner needle valve 61, respectively. The two ends of the outer needle valve return spring 65 located in the outer needle valve control chamber 64 abut against the bottom of the sixth-layer valve block 36 and the top surface of the outer needle valve 62, respectively.

[0035] The control oil circuit 7 is located in the sixth-layer valve block 36 and the injection valve block 37, and is connected to the high-pressure fuel port 9 on the left side of the fifth-layer valve block 35. The control oil circuit 7 includes an inner needle valve control chamber inlet throttling orifice 71, an inner needle valve control chamber return throttling orifice 72, and an inner needle valve control chamber connecting oil port 73, all located in the sixth-layer valve block 36. The upper end of the inclined inner needle valve control chamber connecting oil port 73 is connected to the high-pressure fuel port 9 on one side of the fifth-layer valve block 35, and the lower end is connected to the upper end of the inner needle valve control chamber inlet throttling orifice 71. The lower end of the inner needle valve control chamber inlet throttling orifice 71 passes vertically downward through the central column 361 to the inner needle valve control chamber 63. The vertically arranged inner needle valve control chamber return throttling orifice 72 passes through the center of the sixth-layer valve block 36, and its two ends are connected to the lower control chamber 352 and the inner needle valve control chamber 63, respectively.

[0036] like Figure 3 As shown, a vertically upward-extending outer guide sleeve 375 is provided at the lower center of the lower cavity 373 of the injection valve block. The outer circle of the outer guide sleeve 375 is in clearance fit with the inner hole 621 of the outer needle valve. An annular gap A is left between the inner hole of the outer guide sleeve 375 and the outer circle of the inner needle valve 61. In this embodiment, the ratio of the annular gap A to the radius R of the inner hole of the outer guide sleeve is A / R = 0.20. The annular gap A can also play a throttling and damping role for the high-pressure fuel entering and exiting the bottom of the inner needle valve 61, making the opening and closing of the inner needle valve 61 more stable. The outer guide sleeve 375 improves the stability of the lifting and lowering of the outer needle valve 62, so that when the tapered sleeve 623 at the lower end of the outer needle valve falls, it can completely block several external injection holes 377, thereby improving the opening and closing reliability of the present invention.

[0037] The control air path 8 is located on the right side of the seven valve blocks, from the first valve block 31 to the injection valve block 37. The control air path 8 passes from the bottom of the first valve block 31 downwards through the second valve block 32, the third valve block 33, the fourth valve block 34, the fifth valve block 35 and the sixth valve block 36, and then leads to the outer needle valve control chamber 67 at the top center of the seventh valve block. The control air path 8 includes a control air port 81, an inlet throttle orifice 82 for the control chamber of the external needle valve, a return throttle orifice 83 for the control chamber of the external needle valve, and a return throttle orifice 84 for the upper control chamber. The bottom of the control air port 8 is connected to the upper end of the return throttle orifice 83 for the control chamber of the external needle valve within the sixth layer valve block 36. The lower end of the return throttle orifice 83 for the control chamber of the external needle valve leads to the control chamber 64 of the external needle valve. The lower end of the return throttle orifice 83 for the control chamber of the external needle valve also connects to the middle of the high-pressure gas port 9 through the inlet throttle orifice 82 for the control chamber of the external needle valve. The upper end of the control air port 81 is connected to the return throttle orifice 84 for the upper control chamber, which leads to the top of the upper control chamber 322, through a horizontal connecting hole 85.

[0038] A control method for a dual-fuel electronically controlled injector includes the following corresponding steps for different operating modes:

[0039] A Single Fuel Injection Mode

[0040] When the lower electromagnet 51 is energized, the sum of the electromagnetic force exerted on the lower armature 52 by the lower electromagnet 51 and the fuel pressure exceeds the preload of the lower valve core return spring 54. The lower armature 52 drives the lower valve core 53 to move upward until the top surface of the large end shaft 532 of the lower valve core abuts against the top surface of the lower control chamber 352, at which point the lower valve core 53 stops moving upward. The pressure at the lower end of the lower control chamber 352 decreases, and the lower control chamber 352 connects with the return oil throttle orifice 72 of the inner needle valve control chamber. Fuel in the inner needle valve control chamber 361 enters the lower part of the lower control chamber 352 through the return oil throttle orifice 72, further reducing the fuel pressure in the inner needle valve control chamber 63 until the fuel pressure at the lower end of the inner needle valve 61 exceeds the sum of the fuel pressure at the upper end of the inner needle valve 61 and the preload of the inner needle valve return spring 66. The inner needle valve 61 then moves upward until the inner needle valve return spring 66 is compressed and stops moving upward. The gap between the lower end of the inner needle valve 61 and the inner side of the conical bottom 374 of the lower cavity of the injection valve block increases, and the high-pressure fuel in the lower cavity 373 of the injection valve block is injected out through the annular gap A from several inner injection holes 376.

[0041] B Dual-fuel injection mode

[0042] When the upper electromagnet 41 and the lower electromagnet 51 are energized simultaneously, the sum of the electromagnetic force on the upper armature 42 and the gas pressure on the upper end of the upper armature 42 is greater than the preload of the upper valve core reset spring 44. The upper armature 42 drives the upper valve core 43 to move down until the top surface of the upper valve core large end shaft 432 abuts against the bottom surface 332 of the upper control cavity 332, and the upper valve core 43 stops moving up. The pressure at the upper end of the upper control chamber 332 decreases. The upper control chamber return throttle orifice 84 at the upper end of the upper control chamber 332 is connected to the control air port 81 through the horizontal connecting hole 85. The gas in the outer needle valve control chamber 64 enters the upper part of the upper control chamber 332 in sequence through the outer needle valve control chamber return throttle orifice 83, the control air port 81, the horizontal connecting hole 85, and the upper control chamber return throttle orifice 84, which further reduces the gas pressure in the outer needle valve control chamber 64 until the gas pressure at the lower end of the outer needle valve 62 is greater than the sum of the gas pressure at the upper end of the outer needle valve 62 and the preload force of the outer needle valve return spring 67. The outer needle valve 62 moves upward until the outer needle valve return spring 67 is compressed and no longer rises. The high-pressure gas in the lower chamber 373 of the injection valve block increases through the annular gap between the lower end of the outer needle valve 62 and the inner side of the conical bottom 374 of the lower chamber of the injection valve block. The high-pressure gas in the lower chamber 373 of the injection valve block is ejected from several external injection holes 377.

[0043] At the same time, after the lower electromagnet 51 is energized, the process of single fuel injection mode A is repeated, and the high-pressure fuel in the lower chamber 373 of the injection valve block is injected out from several internal injection holes 376 to complete dual fuel injection.

[0044] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A dual-fuel electronically controlled injector, characterized in that, The system includes an upper cap, a lower housing, and several valve blocks, as well as an upper solenoid valve assembly, a lower solenoid valve assembly, a double needle valve assembly, a control oil circuit, and a control air circuit. The several valve blocks include a first-layer valve block, a second-layer valve block, a third-layer valve block, a fourth-layer valve block, a fifth-layer valve block, a sixth-layer valve block, and an injection valve block. The upper and lower ends of the first-layer valve block are threadedly connected to the lower end of the upper cap and the upper end of the lower housing, respectively. The top of the first-layer valve block abuts against the bottom surface of the threaded hole in the upper cap. The first, second, third, and sixth-layer valve blocks abut against each other. The fourth, fifth, and sixth valve blocks, along with the bottom injection valve block, are sequentially embedded into the lower housing from top to bottom, with a clearance fit. The conical head at the lower end of the injection valve block protrudes from the lower end of the lower housing. The first valve block has a fuel accumulator chamber and a gas accumulator chamber arranged side-by-side and open at the top. High-pressure fuel with a fuel pressure of 16–22 MPa enters the fuel accumulator chamber of the first valve block through the high-pressure fuel inlet connector and high-pressure fuel inlet hole on one side of the top of the upper fastening cap. High-pressure gas with a gas pressure of 12–15 MPa enters the fuel accumulator chamber of the first valve block through the upper fastening cap. The high-pressure gas inlet connector and high-pressure gas inlet port on the other side of the cap's top respectively enter the gas accumulator chamber of the first-layer valve block; the double needle valve assembly is embedded in the central hole of the injection valve block, and the lower end of the double needle valve assembly passes through the lower cavity of the injection valve block, abutting against the inner surface of the conical bottom of the lower cavity of the injection valve block, and blocking several inner and outer injection holes of the lower conical head of the injection valve block, which are respectively connected to the lower cavity of the injection valve block; the bottom of the fuel accumulator chamber passes through the first-layer valve block from top to bottom to the injection valve block. The high-pressure fuel port on one side of the seven-layer valve block is connected to the transverse hole on the outside of the double needle valve assembly; the bottom of the gas accumulator chamber is connected to the lower cavity of the injection valve block through the high-pressure gas port on the other side of the seven-layer valve block, which passes through the first layer valve block to the injection valve block from top to bottom; the upper solenoid valve assembly is set in the third and fourth layer valve blocks, and the lower solenoid valve assembly is set in the fourth and fifth layer valve blocks; the control oil circuit is set in the sixth layer valve block and the injection valve block, and the control air circuit is set in one side of the seven-layer valve block, from the first layer valve block to the injection valve block; The upper and lower solenoid valve assemblies have identical structures and are symmetrically arranged vertically. The upper solenoid valve assembly includes an upper electromagnet, an upper armature, an upper valve core, and an upper valve core return spring. The lower solenoid valve assembly includes a lower electromagnet, a lower armature, a lower valve core, and a lower valve core return spring. Both the upper and lower electromagnets are annular. The upper electromagnet is embedded in the countersunk hole at the upper end of the fourth-layer valve block, and the upper valve core return spring is embedded in the center hole of the upper electromagnet. The two ends of the upper valve core return spring abut against the upper armature and the center of the countersunk hole at the upper end of the fourth-layer valve block, respectively. The upper armature, located above the upper electromagnet, is embedded in the third... The lower valve block is recessed in the lower end of the third layer valve block and fixed to the lower end of the upper valve core. The upper end of the upper valve core is embedded in the upper control cavity, which is located at the center of the upper end of the third layer valve block. The lower electromagnet is embedded in the lower end of the fourth layer valve block, and the lower valve core return spring is embedded in the center hole of the lower electromagnet. The two ends of the lower valve core return spring abut against the lower armature and the center of the lower end of the fourth layer valve block, respectively. The lower armature located below the lower electromagnet is embedded in the upper end of the fifth layer valve block and fixed to the upper end of the lower valve core. The lower end of the lower valve core is embedded in the lower control cavity, which is located at the center of the lower end of the fifth layer valve block. The dual-needle valve assembly includes an inner needle valve, an outer needle valve, an inner needle valve control chamber, an outer needle valve control chamber, an outer needle valve lower chamber, an inner needle valve return spring, and an outer needle valve return spring. The outer needle valve is embedded in the central hole of the injection valve block, and the inner needle valve is embedded in the outer needle valve. The lower conical head of the inner needle valve and the lower conical sleeve of the outer needle valve both pass through the lower chamber of the injection valve block and abut against the conical bottom of the lower chamber of the injection valve block. The lower conical head of the inner needle valve blocks several inner spray holes at the lower end of the injection valve block, and the lower conical sleeve of the outer needle valve blocks several outer spray holes at the lower end of the injection valve block. A transverse hole passes through one side of the middle of the outer needle valve and is connected to the upper part of the lower chamber of the outer needle valve. The sixth-layer valve block has a central column at its bottom that extends into the inner needle valve control chamber. The two ends of the inner needle valve return spring in the inner needle valve control chamber abut against the bottom surface of the central column of the sixth-layer valve block and the top surface of the inner needle valve, respectively. The two ends of the outer needle valve return spring in the outer needle valve control chamber abut against the bottom of the sixth-layer valve block and the top surface of the outer needle valve, respectively. The control oil circuit is connected to the high-pressure fuel port on one side of the fifth-layer valve block. The control air circuit passes from the first-layer valve block downwards through the second, third, fourth, fifth, and sixth-layer valve blocks and then leads to the outer needle valve control chamber at the center of the top of the seventh-layer valve block. The control oil circuit includes an inlet throttling orifice, a return throttling orifice, and a connecting oil hole for the inner needle valve control chamber, all located in the sixth-layer valve block. One end of the inclined connecting oil hole is connected to a high-pressure fuel port on one side of the fifth-layer valve block, and the other end is connected to the upper end of the inlet throttling orifice. The lower end of the inlet throttling orifice passes vertically downward through the central column to the inner needle valve control chamber. The vertically arranged return throttling orifice traverses the center of the sixth-layer valve block, and both ends of the return throttling orifice connect to the lower control chamber and the inner needle valve control chamber, respectively. The control air path includes a control air port, an inlet throttling port for the outer needle valve control chamber, a return throttling port for the outer needle valve control chamber, and a return throttling port for the upper control chamber. The control air port passes sequentially from the bottom of the first valve block downwards through the second, third, fourth, and fifth valve blocks and connects to the upper end of the return throttling port for the outer needle valve control chamber within the sixth valve block. The lower end of the return throttling port for the outer needle valve control chamber leads to the outer needle valve control chamber. The lower end of the return throttling port for the outer needle valve control chamber is also connected to the middle of the high-pressure gas port through the inlet throttling port for the outer needle valve control chamber. The upper end of the control air port is connected to the return throttling port for the upper control chamber, which leads to the top of the upper control chamber, through a horizontal connecting hole.

2. The dual-fuel electronically controlled injector as described in claim 1, characterized in that, Sealing rings are embedded on the top surfaces of the second, third, fourth, fifth, and sixth valve blocks, as well as the top surface of the nozzle valve block.

3. The dual-fuel electronically controlled injector as described in claim 1, characterized in that, Both the upper and lower valve cores are stepped shaft structures. The small end of the stepped shaft of the upper valve core is fixedly connected to the upper armature on the lower side, and the large end of the stepped shaft of the upper valve core is embedded in the upper control cavity. The small end of the stepped shaft of the lower valve core is fixedly connected to the lower armature on the upper side, and the large end of the stepped shaft of the lower valve core is embedded in the lower control cavity.

4. The dual-fuel electronically controlled injector as described in claim 1, characterized in that, The lower center of the lower cavity of the injection valve block is provided with an outer guide sleeve extending vertically upward. The outer circle of the outer guide sleeve is in clearance fit with the inner hole of the outer needle valve. An annular gap A is left between the inner hole of the outer guide sleeve and the outer circle of the inner needle valve. The ratio of the annular gap A to the radius R of the inner hole of the outer guide sleeve is: A / R = 0.19~0.

21.

5. A control method for a dual-fuel electronically controlled injector as described in any one of claims 1 to 4, characterized in that, The following are the corresponding steps for different operating conditions: A Single Fuel Injection Mode When the lower electromagnet is energized, the sum of the electromagnetic force of the lower electromagnet and the fuel pressure on the lower armature is greater than the preload of the lower valve core return spring. The lower armature drives the lower valve core to move upward until the top surface of the large end shaft of the lower valve core abuts against the top surface of the lower control cavity, and the lower valve core stops moving upward. The pressure at the lower end of the lower control chamber decreases, and the lower control chamber connects with the return oil throttle orifice of the inner needle valve control chamber. Fuel in the inner needle valve control chamber enters the lower part of the lower control chamber through the return oil throttle orifice, further reducing the fuel pressure in the inner needle valve control chamber until the fuel pressure at the lower end of the inner needle valve is greater than the sum of the fuel pressure at the upper end of the inner needle valve and the preload force of the inner needle valve return spring. The inner needle valve moves upward until the inner needle valve return spring is compressed and no longer moves upward. The gap between the lower end of the inner needle valve and the inner side of the conical bottom of the lower chamber of the injection valve block increases, and the high-pressure fuel in the lower chamber of the injection valve block is injected out through the gap from several inner injection holes. B Dual-fuel injection mode When both the upper and lower electromagnets are energized simultaneously, the sum of the electromagnetic force on the upper armature and the gas pressure on its upper end exceeds the preload of the upper valve core return spring. The upper armature causes the upper valve core to move downwards until the top surface of the large end shaft of the upper valve core abuts against the bottom surface of the upper control chamber, at which point the upper valve core stops moving upwards. The pressure at the upper end of the upper control chamber decreases, and the upper control chamber return throttling orifice connects to the control gas port through a horizontal connecting hole. Gas in the outer needle valve control chamber passes sequentially through the outer needle valve control chamber return throttling orifice, the control gas port, and water. The gas enters the upper part of the upper control chamber through the flat connection hole and the return gas throttle hole of the upper control chamber, which further reduces the gas pressure in the control chamber of the outer needle valve until the gas pressure at the lower end of the outer needle valve is greater than the sum of the gas pressure at the upper end of the outer needle valve and the preload force of the outer needle valve return spring. The outer needle valve moves upward until the outer needle valve return spring is compressed and no longer rises. The high-pressure gas in the lower chamber of the injection valve block increases the gap between the lower end of the outer needle valve and the inner side of the conical bottom of the lower chamber of the injection valve block, and the high-pressure gas in the lower chamber of the injection valve block is ejected from several external injection holes. At the same time, after the lower electromagnet is energized, the process of single fuel injection mode A is repeated, and the high-pressure fuel in the lower chamber of the injection valve block is injected out from several internal injection holes to complete dual fuel injection.

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