Wide-range methanol / diesel oil dual-fuel injector with high injection stability

Abstract

The invention aims to provide a wide-range methanol / diesel oil dual-fuel injector with high injection stability, and belongs to the field of engines. A methanol injection control multi-way electromagnetic valve assembly is installed in the diesel oil connector body, a diesel oil injection control electromagnetic valve assembly is installed in the injector intermediate body, an oil way stop valve assembly is installed in the cone valve body, multi-position nested needle valve assemblies are installed in the inner needle valve intermediate body and the nozzle body, and a high-pressure methanol connector is installed on the side of the methanol connector body. A high-pressure diesel connector is installed on the side of the diesel connector body. According to the methanol / diesel oil dual-fuel independent injection system, methanol / diesel oil dual-fuel independent injection can be achieved, the methanol injection working condition range can be remarkably widened, the injector needle valve response characteristic is improved, the oil return amount is reduced, and then the methanol injection stability is improved; and various injection modes such as methanol micro-injection, diesel injection and methanol large-flow shoe-shaped injection can be realized.

Description

Technical Field

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

[0002] Energy conservation and emission reduction will be the main development direction in the energy and power sector. Vigorously developing clean, low-carbon or zero-carbon fuels is the fundamental means to reduce environmental pollution and solve emission problems. Reducing carbon dioxide emissions through low-carbon or zero-carbon alternative fuels, such as methanol, hydrogen, and ammonia, provides considerable optimization potential for internal combustion engines. Methanol fuel, due to its wide availability, low carbon content, clean combustion, and low cost, is hailed as one of the most promising renewable low-carbon alternative fuels in the field of internal combustion engines.

[0003] The application of low-carbon fuels is an important means to achieve low-carbon transformation of marine engines. Methanol-diesel high-pressure direct injection technology is currently the most feasible technical solution for methanol dual-fuel marine engines. The design and development of high-pressure methanol / diesel dual-fuel injectors is key to the application of this technology. Existing methanol / diesel dual-fuel injectors use diesel fuel for servo control. To ensure the needle valve opens normally, the methanol injection pressure range and the diesel injection pressure range are limited. Excessive pressure difference between methanol and diesel will cause the needle valve to be normally open or normally closed. Furthermore, the different frequency pressure fluctuations in the diesel and methanol circuits will significantly affect methanol injection performance. Under conditions where the injector needle valve cannot open quickly and completely, its fuel injection stability will be significantly affected by pressure fluctuations, resulting in poor injector injection stability. Summary of the Invention

[0004] The purpose of this invention is to provide a wide-range methanol / diesel dual-fuel injector with high injection stability, which can broaden the methanol injection operating range and improve the methanol injection stability and response characteristics.

[0005] The objective of this invention is achieved as follows: This invention discloses a wide-range methanol / diesel dual-fuel injector with high injection stability, characterized by comprising, from top to bottom, a methanol connector body, a diesel connector body, an injector intermediate body, a cone valve body, an inner needle valve intermediate body, and a nozzle body. A methanol injection control multi-way solenoid valve assembly is installed in the diesel connector body; a diesel injection control solenoid valve assembly is installed in the injector intermediate body; a fuel line shut-off valve assembly is installed in the cone valve body; multi-position nested needle valve assemblies are installed in the inner needle valve intermediate body and the nozzle body; a high-pressure methanol connector is installed on the side of the methanol connector body; a high-pressure methanol pipeline is installed in the high-pressure methanol connector; the high-pressure methanol pipeline sequentially passes through the methanol connector body, the diesel connector body, the injector intermediate body, the cone valve body, and the inner needle valve intermediate body and extends into the nozzle body; a high-pressure diesel connector is installed on the side of the diesel connector body; a high-pressure diesel pipeline is installed in the high-pressure diesel connector; the high-pressure diesel pipeline sequentially passes through the fuel connector body, the injector intermediate body, and the cone valve body and extends into the inner needle valve intermediate body.

[0006] The present invention may also include: 1. The methanol injection control multi-way solenoid valve assembly includes a multi-way solenoid valve core, a multi-way solenoid valve armature, a multi-oil-path control sleeve, a control valve stem, and a control valve core. The multi-way solenoid valve armature is located between the multi-way solenoid valve core and the multi-oil-path control sleeve. A multi-way solenoid valve coil is installed inside the multi-way solenoid valve core. The top of the control valve stem passes through the multi-way solenoid valve armature and is located inside the multi-way solenoid valve core. An armature return spring is provided between the top of the control valve stem and the multi-way solenoid valve core. The control valve core is located inside the multi-oil-path control sleeve. The bottom of the control valve stem is connected to the control valve stem. The multi-oil-path control sleeve is provided with an oil inlet for the upper chamber of the oil circuit shut-off valve, an oil inlet for the outer needle control chamber, a control oil circuit for the oil circuit shut-off valve, a control oil circuit for the outer needle valve control chamber, and a low-pressure return oil circuit. A slot is opened on the control valve core. The slot of the control valve core and the multi-oil-path control sleeve form a primary control ring cavity and a secondary control ring cavity, respectively. The oil inlet for the upper chamber of the oil circuit shut-off valve and the oil inlet for the outer needle control chamber are both connected to the high-pressure diesel pipeline.

[0007] 2. The diesel injection control solenoid valve assembly includes a diesel control solenoid valve core, a diesel control solenoid valve armature, a valve seat body, and a valve stem. The diesel control solenoid valve armature is located between the diesel control solenoid valve core and the valve seat body. The top of the valve stem passes through the diesel control solenoid valve armature and is located inside the diesel control solenoid valve core. A control armature return spring is installed between the top of the valve stem and the diesel control solenoid valve core. The bottom of the valve stem is located inside the valve seat body. A second oil outlet throttling orifice is formed between the bottom of the valve stem and the valve seat body. The valve seat body is provided with a return oil passage, an inner needle control chamber inlet oil passage, and a second inlet throttling orifice. The inner needle control chamber inlet oil passage is connected to the second inlet throttling orifice and the high-pressure diesel pipeline.

[0008] 3. The multi-position nested needle valve assembly includes a hollow inner needle valve, an inner needle valve sleeve, a sleeve-type outer needle valve, and an outer needle valve sleeve. The inner needle valve sleeve is located inside the intermediate body of the inner needle valve. The top of the hollow inner needle valve is located inside the inner needle valve sleeve, and the lower part of the hollow inner needle valve is located inside the sleeve-type outer needle valve. The sleeve-type outer needle valve is installed inside the nozzle body. The top of the hollow inner needle valve, the inner needle valve sleeve, and the cone valve body form an inner needle valve control chamber. An inner needle valve protrusion is provided on the upper part of the hollow inner needle valve. An inner needle valve return spring is installed between the inner needle valve protrusion and the inner needle valve sleeve. The outer needle valve sleeve is sleeved on the top of the sleeve-type outer needle valve and is located below the intermediate body of the inner needle valve. The sleeve-type outer needle valve is provided with an outer needle valve protrusion. An outer needle valve return spring is installed between the outer needle valve protrusion and the outer needle valve sleeve. The inner needle valve intermediate body, the hollow inner needle valve, and the outer needle valve sleeve... An outer needle valve control chamber is formed between the cylinder and the sleeve-type outer needle valve. The hollow inner needle valve is equipped with a diesel inner channel, a high-pressure diesel inlet, and a diesel through hole. A diesel control ring cavity is formed between the hollow inner needle valve and the sleeve-type outer needle valve. The high-pressure diesel inlet, diesel inner channel, and diesel through hole are connected to the diesel control ring cavity. The inner needle valve control chamber is connected to the second inlet throttling orifice and the second outlet throttling orifice, respectively. The inner needle valve intermediate body is equipped with a first inlet throttling orifice and a first outlet throttling orifice, respectively. The outer needle valve control chamber is connected to the first inlet throttling orifice and the first outlet throttling orifice, respectively. The first outlet throttling orifice is connected to the control oil circuit of the outer needle valve control chamber. A methanol control ring cavity is formed between the sleeve-type outer needle valve and the nozzle body. A high-pressure methanol inlet path, a primary spray orifice, and a secondary spray orifice are opened in the nozzle body. The high-pressure methanol inlet path is connected to the methanol control ring cavity and the high-pressure methanol pipeline, respectively.

[0009] 4. The oil circuit shut-off valve assembly includes a conical shut-off valve core located inside the conical valve body. Its cross-section is wider at the top and narrower at the bottom. The upper part of the conical shut-off valve core, together with the conical valve body and the intermediate body of the injector, forms the upper control chamber of the oil circuit shut-off valve. The upper control chamber of the oil circuit shut-off valve is connected to the oil circuit shut-off valve control oil circuit. The lower part of the conical shut-off valve core, together with the conical valve body and the intermediate body of the inner needle valve, forms the lower control chamber of the oil circuit shut-off valve. An oil circuit shut-off valve return spring is installed in the upper control chamber of the oil circuit shut-off valve. The lower control chamber of the oil circuit shut-off valve is connected to the first oil inlet throttle hole. Under the control of the conical shut-off valve core, the lower control chamber of the oil circuit shut-off valve realizes the connection and disconnection with the high-pressure diesel pipeline.

[0010] 5. The control valve stem lift is greater than the diameter of the control oil circuit of the oil circuit shut-off valve, the low-pressure return oil circuit, and the oil inlet circuit of the external needle control chamber. The thickness of the control valve core between the first-stage control ring chamber and the second-stage control ring chamber is less than the diameter of the low-pressure return oil circuit.

[0011] 6. The hollow inner needle valve and the sleeve-type outer needle valve have the same lift. The distance between the diesel through hole and the bottom of the diesel control ring cavity is greater than the lift of the sleeve-type outer needle valve. When the hollow inner needle valve and the sleeve-type outer needle valve are not open, two sealing ring surfaces are formed between the bottom of the hollow inner needle valve and the sleeve-type outer needle valve, and between the hollow inner needle valve and the nozzle body. The diesel control ring cavity is disconnected from the secondary injection hole.

[0012] 7. In diesel injection mode, current is applied to the diesel injection control solenoid valve assembly. The iron core of the diesel control solenoid valve generates electromagnetic force to attract the control armature. The control armature drives the valve stem to move upward, opening the second oil outlet throttle orifice. High-pressure diesel in the inner needle valve control chamber flows to the return oil circuit through the second oil outlet throttle orifice, reducing the diesel pressure in the inner needle valve control chamber. Under the action of hydraulic pressure, the hollow inner needle valve overcomes the preload force of the inner needle valve reset spring and lifts upward. The sealing ring surface formed by the bottom of the hollow inner needle valve and the sleeve-type outer needle valve is misaligned, and the diesel control ring cavity is connected to the secondary injection orifice. Diesel enters the hollow inner needle valve through the high-pressure diesel inlet, passes through the diesel inner channel, diesel through hole, and diesel control ring cavity in sequence, and is ejected through the secondary injection orifice, completing the high-pressure diesel injection.

[0013] 8. In methanol micro-injection mode, current is applied to the methanol injection control multi-way solenoid valve assembly. The iron core of the multi-way solenoid valve generates electromagnetic force to attract the armature of the multi-way solenoid valve. The armature of the multi-way solenoid valve drives the control valve rod and control valve core to move upward. The first-stage control ring chamber and the second-stage control ring chamber rise, the low-pressure return oil circuit is disconnected from the second-stage control ring chamber, and the oil inlet circuit of the outer needle control chamber is disconnected from the first-stage control ring chamber. The control oil circuit of the outer needle control chamber, the first-stage control ring chamber and the low-pressure return oil circuit are connected. The high-pressure diesel fuel in the outer needle valve control chamber flows to the low-pressure return oil circuit through the first outlet throttle orifice, the control oil circuit of the outer needle control chamber and the first-stage control ring chamber. The oil circuit shut-off valve enters the upper chamber. The oil circuit, the secondary control ring chamber, and the oil circuit shut-off valve control oil circuit are connected. Diesel fuel in the high-pressure diesel pipeline enters the upper chamber of the oil circuit shut-off valve through the upper chamber of the oil circuit shut-off valve, the secondary control ring chamber, and the oil circuit shut-off valve control oil circuit. The hydraulic pressure inside the upper chamber of the oil circuit shut-off valve increases. Under the action of hydraulic pressure and the preload of the oil circuit shut-off valve return spring, the conical shut-off valve core moves downward. The first oil inlet throttle orifice is disconnected from the high-pressure diesel pipeline. Under the combined action of the two, the high-pressure diesel fuel in the control chamber of the outer needle valve is released. The sleeve-type outer needle valve is lifted upward under the action of hydraulic pressure, overcoming the preload of the outer needle valve return spring. The hollow inner needle valve and the sleeve-type... A sealing ring is formed at the bottom of the outer needle valve. The distance between the diesel through-hole and the bottom of the diesel control ring cavity is greater than the lift of the sleeve-type outer needle valve. During the rise of the sleeve-type outer needle valve, it still forms a sealing ring with the hollow inner needle valve. Methanol in the high-pressure methanol inlet circuit is sprayed out through the first-stage injection hole. After the injection is completed, the methanol injection control multi-way solenoid valve assembly is de-energized, the control valve core is seated, the low-pressure return oil circuit is disconnected from the first-stage control ring cavity, and the oil inlet circuit of the outer needle control chamber, the first-stage control ring cavity and the control oil circuit of the outer needle control chamber are reconnected. Diesel in the high-pressure diesel pipeline passes sequentially through the oil inlet circuit of the outer needle control chamber, the first-stage control ring cavity and the control oil circuit of the outer needle control chamber and the first outlet. The throttle orifice enters the control chamber of the external needle valve. At the same time, the oil inlet of the upper chamber of the oil circuit shut-off valve is disconnected from the secondary control ring chamber. The low-pressure return oil circuit, the secondary control ring chamber, and the control oil circuit of the oil circuit shut-off valve are reconnected. The high-pressure diesel fuel in the upper chamber of the oil circuit shut-off valve flows sequentially through the control oil circuit of the oil circuit shut-off valve and the secondary control ring chamber to the low-pressure return oil circuit. The conical shut-off valve core opens upward, and the first inlet throttle orifice connects with the high-pressure diesel fuel pipeline. The high-pressure diesel fuel enters the control chamber of the external needle valve simultaneously through the first inlet throttle orifice. With the cooperation of both, the control chamber of the external needle valve completes pressure building. The sleeve-type external needle valve closes under the action of hydraulic pressure and the return spring of the external needle valve, ending the injection.

[0014] 9. In the high-flow-rate shoe-type methanol injection mode, the methanol injection control multi-way solenoid valve assembly and the diesel injection control solenoid valve assembly are simultaneously energized. The control valve core moves upward, connecting the control oil circuit of the outer needle valve chamber, the first-stage control ring chamber, and the low-pressure return oil circuit. High-pressure diesel fuel flows out of the outer needle valve control chamber through the first outlet throttle orifice. The oil circuit shut-off valve control oil circuit connects to the inlet oil circuit of the upper chamber of the oil circuit shut-off valve. The increased hydraulic pressure inside the upper chamber of the oil circuit shut-off valve causes the conical shut-off valve core to seat, disconnecting the first inlet throttle orifice from the high-pressure diesel fuel line. The hydraulic pressure in the outer needle valve control chamber decreases, and the valve stem inside the diesel injection control solenoid valve assembly rises. Diesel fuel in the inner needle valve control chamber passes through the second... The oil outlet throttle orifice flows to the return oil circuit. The oil inlet throttle orifice of the outer needle valve control chamber is cut off, and its fuel release rate is greater than that of the inner needle valve control chamber. The sleeve-type outer needle valve first overcomes the preload force of the outer needle valve return spring and lifts upward. Methanol in the high-pressure methanol pipeline is first injected from the first-stage injection orifice. After the inner needle valve control chamber is depressurized, the hollow inner needle valve overcomes the preload force of the inner needle valve return spring and lifts upward. The hollow inner needle valve and the sleeve-type outer needle valve have the same lift. The sleeve-type outer needle valve and the hollow inner needle valve form a sealing ring surface, which disconnects the diesel control ring cavity from the first-stage injection orifice and the second-stage injection orifice. Methanol in the high-pressure methanol inlet circuit is injected simultaneously from the first-stage injection orifice and the second-stage injection orifice, completing the high-flow shoe-shaped injection of methanol.

[0015] The advantages of this invention are as follows: By cooperating with the methanol injection control multi-way solenoid valve assembly and the oil circuit shut-off valve assembly, this invention enables a more rapid depressurization and pressure build-up process in the external needle valve control chamber. This reduces the negative impact of the coupling between the diesel pressure at the upper end and the methanol pressure at the lower end of the sleeve-type external needle valve on its movement, avoids excessive pressure differences between diesel and methanol that could make the needle valve difficult to open or close, significantly improves the movement speed of the sleeve-type external needle valve, reduces the impact of methanol and diesel coupling pressure fluctuations on the unstable action of the needle valve, improves methanol injection stability, and significantly reduces the amount of oil returned during methanol injection. In addition, this invention also couples the diesel injection control solenoid valve assembly with the multi-position nested needle valve assembly, enabling diesel injection mode, methanol micro-injection mode, and methanol high-flow shoe-type injection mode, etc., to meet the needs of different engine operating conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 A schematic diagram of the structure of a multi-way solenoid valve assembly for methanol injection control; Figure 3 A schematic diagram of the diesel injection control solenoid valve assembly; Figure 4 This is a schematic diagram of a multi-position nested needle valve assembly; Figure 5 This is a schematic diagram of the oil circuit shut-off valve assembly.

[0017] Figure reference numerals: 1: Methanol connector body; 2: High-pressure methanol pipeline; 3: Diesel connector body; 4: Methanol injection control multi-way solenoid valve assembly; 5: Injector body locking nut; 6: Diesel injection control solenoid valve assembly; 7: Injector intermediate body; 8: Cone valve body; 9: Nozzle body locking nut; 10: Inner needle valve intermediate body; 11: Nozzle body; 12: Multi-position nested needle valve assembly; 13: Oil circuit shut-off valve assembly; 14: High-pressure diesel pipeline; 15: High-pressure diesel connector; 16: High-pressure methanol connector.

[0018] 401: Multi-way solenoid valve core; 402: Multi-way solenoid valve coil; 403: Multi-way solenoid valve armature; 404: Armature gasket; 405: Multi-channel control sleeve; 406: Control oil circuit of oil circuit shut-off valve; 407: Control oil circuit of external needle control chamber; 408: Control valve core; 409: Oil inlet of external needle control chamber; 410: Primary control ring cavity; 411: Low-pressure return oil circuit; 412: Oil inlet of upper chamber of oil circuit shut-off valve; 413: Secondary control ring cavity; 414: Lift adjustment sleeve; 415: Control valve stem; 416: Armature return spring.

[0019] 601: Diesel control solenoid valve core; 602: Diesel control solenoid valve coil; 603: Control armature; 604: Air gap adjusting sleeve; 605: Oil return passage; 606: Valve seat body; 607: Second oil inlet throttle hole; 608: Inner needle control chamber oil inlet passage; 609: Second oil outlet throttle hole; 610: Gasket; 611: Valve stem; 612: Control armature return spring.

[0020] 1201: Inner needle valve control chamber; 1202: Inner needle valve sleeve; 1203: Inner needle valve return spring; 1204: Hollow inner needle valve; 1205: First oil outlet throttle orifice; 1206: Outer needle valve control chamber; 1207: Outer needle valve return spring; 1208: Sleeve-type outer needle valve; 1209: High-pressure alcohol inlet path; 1210: Primary injection orifice; 1211: Secondary injection orifice; 1212: Diesel control ring cavity; 1213: Diesel through hole; 1214: Diesel inner channel; 1215: Outer needle valve sleeve; 1216: First oil inlet throttle orifice; 1217: High-pressure diesel oil inlet.

[0021] 1301: Reset spring of oil circuit shut-off valve; 1302: Upper control chamber of oil circuit shut-off valve; 1303: Conical shut-off valve core; 1304: Lower control chamber of oil circuit shut-off valve. Detailed Implementation

[0022] The invention will now be described in more detail with reference to the accompanying drawings: Implementation method 1: Combining Figure 1-5This embodiment describes a wide-range methanol / diesel dual-fuel injector with high injection stability, comprising a methanol connector body 1, a diesel connector body 3, a methanol injection control multi-way solenoid valve assembly 4, an injector body locking nut 5, a diesel injection control solenoid valve assembly 6, an injector intermediate body 7, a cone valve body 8, a nozzle body locking nut 9, an inner needle valve intermediate body 10, a nozzle body 11, a multi-position nested needle valve assembly 12, a fuel line shut-off valve assembly 13, a high-pressure diesel connector 15, and a high-pressure methanol connector 16. The diesel connector body 3, injector intermediate body 7, cone valve body 8, inner needle valve intermediate body 10, and nozzle body 11 are installed sequentially from top to bottom inside the injector body locking nut 5 and the nozzle body locking nut 9. The methanol connector body 1, diesel connector body 3, and injector body 16 are also described. The injector intermediate body 7, cone valve body 8, inner needle valve intermediate body 10, and nozzle body 11 are all equipped with high-pressure methanol pipelines 2. The diesel connector body 3, injector intermediate body 7, cone valve body 8, and inner needle valve intermediate body 10 are equipped with high-pressure diesel pipelines 14. The high-pressure methanol pipeline 2 is connected to the multi-position nested needle valve assembly 12. The high-pressure diesel pipeline 14 is connected to the methanol injection control multi-way solenoid valve assembly 4, the diesel injection control solenoid valve assembly 6, the multi-position nested needle valve assembly 12, and the oil circuit shut-off valve assembly 13. The methanol injection control multi-way solenoid valve assembly 4 is installed in the diesel connector body 3, the diesel injection control solenoid valve assembly 6 is installed in the injector intermediate body 7, and the multi-position nested needle valve assembly 12 is installed in the inner needle valve intermediate body 10 and nozzle body 11.

[0023] Implementation Method 2: Based on Implementation Method 1, the methanol injection control multi-way solenoid valve assembly 4 includes a multi-way solenoid valve core 401, a multi-way solenoid valve coil 402, a multi-way solenoid valve armature 403, an armature gasket 404, a multi-oil-path control sleeve 405, a control valve core 408, a lift adjustment sleeve 414, a control valve stem 415, and an armature return spring 416. The multi-oil-path control sleeve 405 is internally equipped with an oil circuit control oil circuit 406 for the oil circuit shut-off valve, an external needle control chamber control oil circuit 407, an external needle control chamber inlet oil circuit 409, a low-pressure return oil circuit 411, and an oil circuit inlet oil circuit 412 for the upper chamber of the oil circuit shut-off valve. The control valve core 408 and the control valve stem 415 are connected by threads. The multi-oil-path control sleeve 405 is fitted over the control valve core 408. An annular groove is formed on the control valve core 408. 5. The control valve core 408 cooperates with the control valve core 408 to form a primary control ring cavity 410 and a secondary control ring cavity 413. The thickness of the control valve core 408 between the primary control ring cavity 410 and the secondary control ring cavity 413 is less than the diameter of the low-pressure return oil circuit 411. The lift of the control valve stem 415 is greater than the diameter of the oil circuit shut-off valve control oil circuit 406, the low-pressure return oil circuit 411 and the outer needle control chamber inlet oil circuit 409. When the control valve core 408 is at the bottom dead center, the low-pressure return oil circuit 411 is located at the bottom of the secondary control ring cavity 413, the oil circuit shut-off valve control oil circuit 406 is located at the top of the secondary control ring cavity 413, the outer needle control chamber inlet oil circuit 409 is located at the bottom of the primary control ring cavity 410, the outer needle control chamber control oil circuit 407 is located at the top of the primary control ring cavity 410, and the upper chamber inlet oil circuit 412 of the oil circuit shut-off valve is closed by the control valve core 408.

[0024] Implementation Method 3: Based on Implementation Method 1, the diesel injection control solenoid valve assembly 6 includes a diesel control solenoid valve core 601, a diesel control solenoid valve coil 602, a control armature 603, an air gap adjusting sleeve 604, a valve seat body 606, a gasket 610, a valve stem 611, and a control armature return spring 611. The valve seat body 606 is provided with a return oil passage 605, a second oil inlet throttle hole 607, an inner needle control chamber oil inlet passage 608, and a second oil outlet throttle hole 609. The inner needle control chamber oil inlet passage 608 is connected to the high-pressure diesel pipeline 14 provided in the injector intermediate body 7. When the diesel control solenoid valve coil 602 is not energized, the control armature return spring 611 presses the valve stem 611 tightly against the valve seat body 606, and the second oil inlet throttle hole 607 is not connected to the return oil passage 605.

[0025] Implementation Method 4: Based on Implementation Method 1, the multi-position nested needle valve assembly 12 includes an inner needle valve sleeve 1202, an inner needle valve return spring 1203, a hollow inner needle valve 1204, a first oil outlet throttling orifice 1205, an outer needle valve return spring 1207, a sleeve-type outer needle valve 1208, a high-pressure alcohol inlet path 1209, a primary spray orifice 1210, a secondary spray orifice 1211, an outer needle valve sleeve 1215, and a first oil inlet throttling orifice 1216. The inner needle valve sleeve 1202 is fitted onto the upper end of the hollow inner needle valve 1204. 1202. The hollow inner needle valve 1204 and the cone valve body 8 work together to form the inner needle valve control chamber 1201. The hollow inner needle valve 1204 is provided with a diesel inner channel 1214 and a high-pressure diesel inlet 1217. The sleeve-type outer needle valve 1208 is installed outside the hollow inner needle valve 1204. The hollow inner needle valve 1204, the sleeve-type outer needle valve 1208, the outer needle valve sleeve 1215 and the inner needle valve intermediate body 10 work together to form the outer needle valve control chamber 1206. The first oil outlet throttle orifice 1205 and the first oil inlet throttle orifice 1216 are connected. Located above the external needle valve control chamber 1206, the first oil inlet throttle orifice 1216 is connected to the oil circuit shut-off valve assembly 13, and the first oil outlet throttle orifice 1205 is connected to the control oil circuit 407 of the external needle valve control chamber. A concave annular groove is opened at the lower end of the sleeve-type external needle valve 1208. The hollow inner needle valve 1204 cooperates with the sleeve-type external needle valve 1208 to form a diesel control annular cavity 1212. A diesel through hole 1213 is provided at the lower end of the hollow inner needle valve 1204. The high-pressure diesel inlet hole 1217, the diesel inner channel 1214, the diesel through hole 1213 and the diesel control... The annular cavity 1212 is connected, and two sealing annular surfaces will be formed between the bottom of the hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208, and between the hollow inner needle valve 1204 and the nozzle body 11. The hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208 have the same stroke. The distance between the diesel through hole 1213 and the bottom of the diesel control annular cavity 1212 is greater than the stroke of the sleeve-type outer needle valve 1208. When the hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208 are not open, the diesel control annular cavity 1212 is not connected to the secondary injection hole 1211.

[0026] Implementation Method 5: Based on Implementation Method 1, the shut-off oil circuit shut-off valve assembly 13 includes an oil circuit shut-off valve return spring 1301 and a conical shut-off valve core 1303. The conical shut-off valve core 1303 is installed in the conical valve body 8. The conical shut-off valve core 1303, the conical valve body 8, and the inner needle valve intermediate body 10 respectively cooperate to form the upper control chamber 1302 and the lower control chamber 1304 of the oil circuit shut-off valve. The upper control chamber 1302 of the oil circuit shut-off valve is connected to the oil circuit shut-off valve control oil circuit 406, and the lower control chamber 1304 of the oil circuit shut-off valve is connected to the first oil inlet throttling hole 1216.

[0027] Implementation Method 6: Based on Implementation Method 1, the lift of the control valve stem 415 is greater than the diameter of the control oil circuit 406 of the oil circuit shut-off valve, the low-pressure return oil circuit 411 and the oil inlet circuit 409 of the outer needle control chamber, and the thickness of the control valve core 408 between the primary control ring cavity 410 and the secondary control ring cavity 413 is less than the diameter of the low-pressure return oil circuit 411.

[0028] Implementation Method 7: Based on Implementation Method 1, the hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208 have the same lift. The distance between the diesel through hole 1213 and the bottom of the diesel control ring cavity 1212 is greater than the lift of the sleeve-type outer needle valve 1208. When the hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208 are not open, two sealing ring surfaces are formed between the bottom of the hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208, and between the hollow inner needle valve 1204 and the nozzle body 11. The diesel control ring cavity 1212 is disconnected from the secondary injection hole 1211.

[0029] Implementation Method 8: Based on Implementation Method 1, in diesel injection mode, current is supplied to the diesel control solenoid valve coil 602 in the diesel injection control solenoid valve assembly 6. The diesel control solenoid valve core 601 generates electromagnetic force to attract the control armature 603. The control armature 603 drives the valve stem 611 to move upward, opening the second oil outlet throttle orifice 609. The high-pressure diesel in the inner needle valve control chamber 1201 flows to the return oil circuit 605 through the second oil outlet throttle orifice 609, reducing the diesel pressure in the inner needle valve control chamber 1201. Under the action of hydraulic pressure, the hollow inner needle valve 1204 overcomes the preload force of the inner needle valve return spring 1203 and lifts upward. The hollow inner needle valve 1204 and the bottom of the sleeve-type outer needle valve 1208... The formed sealing ring surfaces are offset. Diesel fuel enters through the high-pressure diesel fuel inlet 1217, passes through the diesel fuel inner channel 1214, diesel fuel through hole 1213, and diesel fuel control ring cavity 1212 in sequence, and is finally ejected through the secondary injection hole 1211. After the injection is completed, the diesel fuel control solenoid valve coil 602 is de-energized, the valve stem 611 is seated, the second oil outlet throttle hole 609 is closed, and the high-pressure diesel fuel enters the inner needle valve control chamber 1201 through the second oil inlet throttle hole 607. The hollow inner needle valve 1204 is seated under the action of the needle valve return spring. The hollow inner needle valve 1204 and the bottom of the sleeve-type outer needle valve 1208, and the hollow inner needle valve 1204 and the nozzle body 11 re-form two sealing ring surfaces, thus ending the high-pressure diesel fuel injection.

[0030] Implementation Method 9: Based on Implementation Method 1, in methanol micro-injection mode, current is applied to the multi-way solenoid valve coil 402 in the methanol injection control multi-way solenoid valve assembly 4. The multi-way solenoid valve core 401 generates electromagnetic force to attract the multi-way solenoid valve armature 403. The multi-way solenoid valve armature 403 drives the control valve rod 415 and the control valve core 408 to move upward. The upward movement of the control valve core 408 causes the primary control ring cavity 410 and the secondary control ring cavity 413 to move synchronously. At this time, the low-pressure return oil circuit 411 is disconnected from the secondary control ring cavity 413, and the oil inlet circuit 409 of the external needle control chamber is opened. Disconnected from the primary control loop chamber 410, the control oil circuit 407 of the outer needle control chamber, the primary control loop chamber 410, and the low-pressure return oil circuit 411 are connected. High-pressure diesel fuel in the outer needle valve control chamber 1206 flows to the low-pressure return oil circuit 411 through the first outlet throttle orifice 1205, the control oil circuit 407 of the outer needle control chamber, and the primary control loop chamber 410. Simultaneously, the oil inlet circuit 412 of the upper chamber of the oil circuit shut-off valve and the secondary control loop chamber 413 are connected to the oil circuit shut-off valve control oil circuit 406. Diesel fuel in the high-pressure diesel fuel pipeline 14 flows through the oil inlet circuit 412 of the upper chamber of the oil circuit shut-off valve and the secondary control loop chamber 411. 13. The oil circuit 406, which controls the oil circuit shut-off valve, enters the upper control chamber 1302 of the oil circuit shut-off valve, increasing the hydraulic pressure inside the upper control chamber 1302. Under the action of the hydraulic pressure and the return spring 1301 of the oil circuit shut-off valve, the conical shut-off valve core 1303 moves downward, disconnecting the first inlet throttle orifice 1216 from the high-pressure diesel pipeline 14. The high-pressure diesel cannot enter the outer needle valve control chamber 1206 through the first inlet throttle orifice 1216. Under the combined action of the two, the high-pressure diesel is rapidly released in the outer needle valve control chamber 1206, and the return oil volume is significant. As the pressure decreases, the sleeve-type external needle valve 1208 quickly rises upwards, overcoming the preload of the external needle valve return spring 1207. Since the hollow inner needle valve 1204 and the bottom of the sleeve-type external needle valve 1208 form a sealing ring surface, and the distance between the diesel through hole 1213 and the bottom of the diesel control ring cavity 1212 is greater than the lift of the sleeve-type external needle valve 1208, the sleeve-type external needle valve 1208 can still form a sealing ring surface with the hollow inner needle valve 1204 during the upward process. Diesel will not flow out from the diesel injection hole, and methanol in the high-pressure methanol inlet 1209 is sprayed out from the first-stage injection hole 1210.After injection, the multi-way solenoid valve coil 402 is de-energized, and the control valve core 408 sits down, disconnecting the low-pressure return oil circuit 411 from the first-stage control ring chamber 410. The outer needle control chamber inlet oil circuit 409, the first-stage control ring chamber 410, and the outer needle control chamber control oil circuit 407 are reconnected. Diesel fuel in the high-pressure diesel pipeline 14 passes sequentially through the outer needle control chamber inlet oil circuit 409, the first-stage control ring chamber 410, and the outer needle control chamber control oil circuit 407, and enters the outer needle valve control chamber 1206 through the first oil outlet throttle orifice 1205. The oil circuit inlet oil circuit 412 of the upper chamber of the oil circuit shut-off valve is disconnected from the second-stage control ring chamber 413, and the low-pressure return oil circuit 411, the second-stage control ring chamber 413, and the oil circuit shut-off valve control oil circuit are reconnected. 406 is reconnected. The high-pressure diesel fuel in the upper chamber 1302 controlled by the oil circuit shut-off valve flows sequentially through the oil circuit shut-off valve control oil circuit 406 and the secondary control ring chamber 413 to the low-pressure return oil circuit 411. The hydraulic pressure in the upper chamber 1302 controlled by the oil circuit shut-off valve decreases, causing the conical shut-off valve core 1303 to open upwards. The first inlet throttle orifice 1216 connects with the high-pressure diesel fuel pipeline 14. The high-pressure diesel fuel enters the outer needle valve control chamber 1206 simultaneously through the first inlet throttle orifice 1216. With the cooperation of both, the outer needle valve control chamber 1206 quickly completes the pressure building process. Under the action of hydraulic pressure and the outer needle valve return spring 1207, the sleeve-type outer needle valve 1208 quickly closes, ending methanol injection.

[0031] Implementation Method 10: Based on Implementation Method 1, in the methanol high-flow shoe-type injection mode, current is simultaneously applied to the methanol injection control multi-way solenoid valve assembly 4 and the diesel injection control solenoid valve assembly 6. The control valve core 408 in the methanol injection control multi-way solenoid valve assembly 4 moves upward, causing the control oil circuit 407 of the outer needle control chamber to disconnect from the oil inlet circuit 409 of the outer needle control chamber. The first-stage control ring cavity 410 and the low-pressure return oil circuit 411 are connected to the control oil circuit 407 of the outer needle control chamber. The high-pressure diesel in the outer needle valve control chamber 1206 flows sequentially through the first oil outlet throttle orifice 1205, the control oil circuit 407 of the outer needle control chamber, the first-stage control ring cavity 410, and the low-pressure return oil circuit 409. Oil flows out of return line 411, and simultaneously, the oil circuit shut-off valve controls the oil circuit 406 and connects to the oil inlet line 412 of the upper chamber of the oil circuit shut-off valve. The increased hydraulic pressure inside the upper chamber 1302 of the oil circuit shut-off valve causes the conical shut-off valve core 1303 to sit down, disconnecting the first inlet throttle orifice 1216 from the high-pressure diesel pipeline 14. Fuel cannot be replenished in the outer needle valve control chamber 1206. At the same time, the valve stem 611 inside the diesel injection control solenoid valve assembly 6 is raised, and diesel in the inner needle valve control chamber 1201 flows to the return line 605 through the second outlet throttle orifice 609. Under the combined effect of the two, the fuel release rate in the outer needle valve control chamber 1206 is greater than that in the inner needle valve control chamber 1201. 01. Therefore, the sleeve-type external needle valve 1208 first overcomes the preload force of the external needle valve return spring 1207 and lifts upward. Methanol in the high-pressure methanol pipeline 2 is first sprayed out from the first-stage injection hole 1210. Then, after the internal needle valve control chamber 1201 is depressurized, the hollow internal needle valve 1204 overcomes the preload force of the internal needle valve return spring 1203 and lifts upward. Since the hollow internal needle valve 1204 and the sleeve-type external needle valve 1208 have the same lift, the sleeve-type external needle valve 1208 and the hollow internal needle valve 1204 will still form a sealing ring surface. The diesel control ring cavity 1212 is disconnected from the first-stage injection hole 1210 and the second-stage injection hole 1211, and methanol in the high-pressure methanol inlet 1209... Methanol is injected simultaneously through the primary nozzle 1210 and the secondary nozzle 1211, completing a high-flow-rate shoe-shaped injection of methanol. After the injection is completed, due to the slightly slower pressure build-up process in the inner needle valve control chamber 1201, the diesel control solenoid valve coil 602 is de-energized first, and the second oil outlet throttle orifice 609 is closed. High-pressure diesel enters the inner needle valve control chamber 1201 through the second oil inlet throttle orifice 607. Then, the multi-way solenoid valve coil 402 is de-energized, and the high-pressure diesel enters the outer needle valve control chamber 1206 simultaneously through the first oil inlet throttle orifice 1216 and the first oil outlet throttle orifice 1205. The hollow inner needle valve 1204 and the sleeve-type outer needle valve 1208 are seated simultaneously, ending the injection.

[0032] The present invention, through the cooperation of the methanol injection control multi-way solenoid valve assembly 4 and the oil circuit shut-off valve assembly 13, enables the external needle valve control chamber 1206 to achieve a more rapid depressurization and pressure build-up process, weakens the coupling effect between the diesel pressure at the upper end and the methanol pressure at the lower end of the sleeve-type external needle valve 1208, avoids the needle valve being difficult to open or close due to excessive difference between diesel and methanol pressure, increases the movement speed of the sleeve-type external needle valve 1208, reduces the return oil volume, reduces the impact of pressure fluctuations on the unstable action of the needle valve, and improves fuel injection stability. Through the flexible matching of the diesel injection control solenoid valve assembly 6 and the multi-position nested needle valve assembly 12, modes such as diesel injection mode, methanol micro-injection mode, and methanol high-flow shoe-type injection mode can be realized.

Claims

1. A wide-range methanol / diesel dual-fuel injector with high injection stability, characterized in that: The system comprises, from top to bottom, a methanol connector body, a diesel connector body, an injector intermediate body, a cone valve body, an inner needle valve intermediate body, and a nozzle body. A methanol injection control multi-way solenoid valve assembly is installed in the diesel connector body. A diesel injection control solenoid valve assembly is installed in the injector intermediate body. An oil circuit shut-off valve assembly is installed in the cone valve body. Multi-position nested needle valve assemblies are installed in the inner needle valve intermediate body and the nozzle body. A high-pressure methanol connector is installed on the side of the methanol connector body, containing a high-pressure methanol pipeline. The high-pressure methanol pipeline passes sequentially through the methanol connector body, diesel connector body, injector intermediate body, cone valve body, and inner needle valve intermediate body before extending into the nozzle body. A high-pressure diesel connector is installed on the side of the diesel connector body, containing a high-pressure diesel pipeline. The high-pressure diesel pipeline passes sequentially through the oil connector body, injector intermediate body, and cone valve body before extending into the inner needle valve intermediate body.

2. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: The methanol injection control multi-way solenoid valve assembly includes a multi-way solenoid valve core, a multi-way solenoid valve armature, a multi-oil-path control sleeve, a control valve stem, and a control valve core. The multi-way solenoid valve armature is located between the multi-way solenoid valve core and the multi-oil-path control sleeve. A multi-way solenoid valve coil is installed inside the multi-way solenoid valve core. The top of the control valve stem passes through the multi-way solenoid valve armature and is located inside the multi-way solenoid valve core. An armature return spring is installed between the top of the control valve stem and the multi-way solenoid valve core. The control valve core is located inside the multi-oil-path control sleeve. The bottom of the control valve stem is connected to the control valve stem. The multi-oil-path control sleeve is provided with an oil inlet for the upper chamber of the oil circuit shut-off valve, an oil inlet for the outer needle control chamber, a control oil circuit for the oil circuit shut-off valve, a control oil circuit for the outer needle valve control chamber, and a low-pressure return oil circuit. A slot is opened on the control valve core. The slot of the control valve core and the multi-oil-path control sleeve form a primary control ring cavity and a secondary control ring cavity, respectively. The oil inlet for the upper chamber of the oil circuit shut-off valve and the oil inlet for the outer needle control chamber are both connected to the high-pressure diesel pipeline.

3. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: The diesel injection control solenoid valve assembly includes a diesel control solenoid valve core, a diesel control solenoid valve armature, a valve seat body, and a valve stem. The diesel control solenoid valve armature is located between the diesel control solenoid valve core and the valve seat body. The top of the valve stem passes through the diesel control solenoid valve armature and is located inside the diesel control solenoid valve core. A control armature return spring is installed between the top of the valve stem and the diesel control solenoid valve core. The bottom of the valve stem is located inside the valve seat body. A second oil outlet throttling orifice is formed between the bottom of the valve stem and the valve seat body. The valve seat body is provided with a return oil passage, an inner needle control chamber inlet oil passage, and a second inlet throttling orifice. The inner needle control chamber inlet oil passage is connected to the second inlet throttling orifice and the high-pressure diesel pipeline.

4. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: The multi-position nested needle valve assembly includes a hollow inner needle valve, an inner needle valve sleeve, a sleeve-type outer needle valve, and an outer needle valve sleeve. The inner needle valve sleeve is located inside the inner needle valve intermediate body. The top of the hollow inner needle valve is located inside the inner needle valve sleeve, and the lower part of the hollow inner needle valve is located inside the sleeve-type outer needle valve. The sleeve-type outer needle valve is installed inside the nozzle body. The top of the hollow inner needle valve, the inner needle valve sleeve, and the cone valve body form an inner needle valve control chamber. An inner needle valve protrusion is provided on the upper part of the hollow inner needle valve. An inner needle valve return spring is installed between the inner needle valve protrusion and the inner needle valve sleeve. The outer needle valve sleeve is fitted onto the top of the sleeve-type outer needle valve and is located below the inner needle valve intermediate body. The sleeve-type outer needle valve is provided with an outer needle valve protrusion, and an outer needle valve return spring is installed between the outer needle valve protrusion and the outer needle valve sleeve. The inner needle valve intermediate body, the hollow inner needle valve, and the outer needle valve sleeve are all present. The sleeve-type outer needle valve forms an outer needle valve control chamber. The hollow inner needle valve is equipped with a diesel inner channel, a high-pressure diesel inlet, and a diesel through hole. The hollow inner needle valve and the sleeve-type outer needle valve form a diesel control ring cavity. The high-pressure diesel inlet, diesel inner channel, and diesel through hole are connected to the diesel control ring cavity. The inner needle valve control chamber is connected to the second inlet throttle orifice and the second outlet throttle orifice. The inner needle valve intermediate body is equipped with a first inlet throttle orifice and a first outlet throttle orifice. The outer needle valve control chamber is connected to the first inlet throttle orifice and the first outlet throttle orifice. The first outlet throttle orifice is connected to the control oil circuit of the outer needle valve control chamber. The sleeve-type outer needle valve and the nozzle body form a methanol control ring cavity. The nozzle body is equipped with a high-pressure methanol inlet path, a primary spray orifice, and a secondary spray orifice. The high-pressure methanol inlet path is connected to the methanol control ring cavity and the high-pressure methanol pipeline.

5. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: The oil circuit shut-off valve assembly includes a conical shut-off valve core located inside the conical valve body. The conical shut-off valve core has a cross-section that is wider at the top and narrower at the bottom. The upper part of the conical shut-off valve core, together with the conical valve body and the intermediate body of the injector, forms the upper control chamber of the oil circuit shut-off valve, which is connected to the oil circuit shut-off valve control oil circuit. The lower part of the conical shut-off valve core, together with the conical valve body and the intermediate body of the inner needle valve, forms the lower control chamber of the oil circuit shut-off valve. An oil circuit shut-off valve return spring is installed in the upper control chamber of the oil circuit shut-off valve, and the lower control chamber of the oil circuit shut-off valve is connected to the first oil inlet throttle orifice. Under the control of the conical shut-off valve core, the lower control chamber of the oil circuit shut-off valve realizes the opening and closing of the high-pressure diesel pipeline.

6. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: The control valve stem lift is greater than the diameter of the control oil circuit of the oil circuit shut-off valve, the low-pressure return oil circuit, and the oil inlet circuit of the external needle control chamber. The thickness of the control valve core between the first-stage control ring cavity and the second-stage control ring cavity is less than the diameter of the low-pressure return oil circuit.

7. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: The hollow inner needle valve and the sleeve-type outer needle valve have the same lift. The distance between the diesel through hole and the bottom of the diesel control ring cavity is greater than the lift of the sleeve-type outer needle valve. When the hollow inner needle valve and the sleeve-type outer needle valve are not open, two sealing ring surfaces are formed between the bottom of the hollow inner needle valve and the sleeve-type outer needle valve, and between the hollow inner needle valve and the nozzle body. The diesel control ring cavity is disconnected from the secondary injection hole.

8. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: In diesel injection mode, current is applied to the diesel injection control solenoid valve assembly. The solenoid valve core generates electromagnetic force to attract the control armature, which in turn moves the valve stem upward. The second outlet throttle orifice opens, and the high-pressure diesel in the inner needle valve control chamber flows to the return oil circuit through the second outlet throttle orifice. The diesel pressure in the inner needle valve control chamber decreases, and the hollow inner needle valve lifts upward under hydraulic pressure, overcoming the preload of the inner needle valve return spring. The sealing ring formed by the bottom of the hollow inner needle valve and the sleeve-type outer needle valve is misaligned, and the diesel control ring cavity is connected to the secondary injection orifice. Diesel enters the hollow inner needle valve through the high-pressure diesel inlet, passes through the diesel inner channel, diesel through hole, and diesel control ring cavity in sequence, and is ejected through the secondary injection orifice, completing the high-pressure diesel injection.

9. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: In methanol micro-injection mode, current is applied to the methanol injection control multi-way solenoid valve assembly. The iron core of the multi-way solenoid valve generates electromagnetic force to attract the armature of the multi-way solenoid valve. The armature of the multi-way solenoid valve drives the control valve rod and control valve core to move upward. The primary control ring chamber and the secondary control ring chamber rise, the low-pressure return oil circuit is disconnected from the secondary control ring chamber, and the oil inlet circuit of the outer needle control chamber is disconnected from the primary control ring chamber. The control oil circuit of the outer needle control chamber, the primary control ring chamber and the low-pressure return oil circuit are connected. The high-pressure diesel fuel in the outer needle valve control chamber flows to the low-pressure return oil circuit through the first oil outlet throttle orifice, the control oil circuit of the outer needle control chamber and the primary control ring chamber. Oil enters the upper chamber of the oil circuit shut-off valve. The secondary control loop chamber and the oil circuit shut-off valve control oil circuit are connected. Diesel fuel in the high-pressure diesel pipeline enters the oil circuit through the upper chamber of the oil circuit shut-off valve and the secondary control loop chamber and the oil circuit shut-off valve control oil circuit. The hydraulic pressure inside the upper chamber of the oil circuit shut-off valve control increases. Under the action of hydraulic pressure and the preload of the oil circuit shut-off valve return spring, the conical shut-off valve core moves downward. The first oil inlet throttle orifice is disconnected from the high-pressure diesel pipeline. Under the combined action of the two, the high-pressure diesel fuel in the control chamber of the outer needle valve is released. The sleeve-type outer needle valve is lifted upward under the action of hydraulic pressure, overcoming the preload of the outer needle valve return spring. The hollow inner needle valve and the sleeve-type outer needle valve... A sealing ring is formed at the bottom of the needle valve. The distance between the diesel through-hole and the bottom of the diesel control ring cavity is greater than the lift of the sleeve-type external needle valve. During the rise of the sleeve-type external needle valve, it still forms a sealing ring with the hollow inner needle valve. Methanol in the high-pressure methanol inlet circuit is sprayed out through the primary injection hole. After the injection is completed, the methanol injection control multi-way solenoid valve assembly is de-energized, the control valve core is seated, the low-pressure return oil circuit is disconnected from the primary control ring cavity, and the oil inlet circuit of the external needle control chamber, the primary control ring cavity and the control oil circuit of the external needle control chamber are reconnected. Diesel in the high-pressure diesel pipeline passes sequentially through the oil inlet circuit of the external needle control chamber, the primary control ring cavity and the control oil circuit of the external needle control chamber and the first oil outlet section. The flow orifice enters the control chamber of the external needle valve. At the same time, the oil inlet of the upper chamber of the oil circuit shut-off valve is disconnected from the secondary control ring chamber. The low-pressure return oil circuit, the secondary control ring chamber, and the control oil circuit of the oil circuit shut-off valve are reconnected. The high-pressure diesel fuel in the upper chamber of the oil circuit shut-off valve flows sequentially through the control oil circuit of the oil circuit shut-off valve and the secondary control ring chamber to the low-pressure return oil circuit. The conical shut-off valve core opens upward, and the first inlet throttle orifice is connected to the high-pressure diesel fuel pipeline. The high-pressure diesel fuel enters the control chamber of the external needle valve simultaneously through the first inlet throttle orifice. With the cooperation of both, the control chamber of the external needle valve completes the pressure build-up. The sleeve-type external needle valve closes under the action of hydraulic pressure and the return spring of the external needle valve, ending the injection.

10. A wide-range methanol / diesel dual-fuel injector with high injection stability according to claim 1, characterized in that: In the high-flow-rate shoe-type methanol injection mode, both the methanol injection control multi-way solenoid valve assembly and the diesel injection control solenoid valve assembly are simultaneously energized. This causes the control valve core to move upwards, connecting the control oil circuit of the outer needle valve control chamber, the first-stage control ring chamber, and the low-pressure return oil circuit. High-pressure diesel fuel flows out of the outer needle valve control chamber through the first outlet throttle orifice. The oil circuit shut-off valve control oil circuit connects to the inlet oil circuit of the upper chamber of the oil circuit shut-off valve. The increased hydraulic pressure inside the upper chamber of the oil circuit shut-off valve causes the conical shut-off valve core to seat, disconnecting the first inlet throttle orifice from the high-pressure diesel fuel line. The hydraulic pressure in the outer needle valve control chamber decreases, causing the valve stem inside the diesel injection control solenoid valve assembly to rise. Diesel fuel from the inner needle valve control chamber then flows through the second outlet... The oil throttle orifice flows to the return oil circuit. The oil inlet throttle orifice of the outer needle valve control chamber is cut off, and its fuel release rate is greater than that of the inner needle valve control chamber. The sleeve-type outer needle valve first overcomes the preload force of the outer needle valve return spring and lifts upward. Methanol in the high-pressure methanol pipeline is first injected from the first-stage injection orifice. After the inner needle valve control chamber is depressurized, the hollow inner needle valve overcomes the preload force of the inner needle valve return spring and lifts upward. The hollow inner needle valve and the sleeve-type outer needle valve have the same lift. The sleeve-type outer needle valve and the hollow inner needle valve form a sealing ring surface, which disconnects the diesel control ring cavity from the first-stage injection orifice and the second-stage injection orifice. Methanol in the high-pressure methanol inlet circuit is injected simultaneously from the first-stage injection orifice and the second-stage injection orifice, completing the high-flow shoe-shaped injection of methanol.

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