Single-nozzle dual-fuel injector, engine and control method

Abstract

The invention discloses a single-nozzle dual-fuel injector, an engine and a control method. The injector comprises an injector body, and a first nozzle is formed in the bottom end of the injector body; a first oil inlet and a second oil inlet which are used for inputting first fuel and second fuel into the device body are respectively formed in the upper part of the device body; the first nozzle is communicated with a first valve cavity in the device body through a first oil duct; a first needle valve capable of sliding in a reciprocating mode is inserted into the first valve cavity, and a first control mechanism is arranged at the upper end of the first needle valve. A one-way valve is arranged on the first oil duct; the second oil inlet is communicated with a second valve cavity in the device body, a second needle valve capable of sliding in a reciprocating mode is inserted in the second valve cavity, and a second control mechanism is arranged at one end of the second needle valve. The second nozzle is arranged in the device body and is communicated with the second oil duct; and the other end of the second oil duct is communicated with the first valve cavity. Two kinds of fuel share one nozzle, the two kinds of fuel can be independently injected in an electric control mode, then the fuel injector can be replaced for an engine used in the market, a cylinder cover does not need to be replaced, and upgrading and reconstruction are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of engines, and in particular relates to a single-nozzle dual-fuel injector, an engine and a control method. Background Art

[0002] With the rapid development of the global economy, coupled with the unsustainability of traditional fuels and pollution to the ecological environment, people are paying more and more attention to the development of new fuels. Engine design and manufacturing companies around the world are also constantly seeking to develop new fuel internal combustion engines. Combining the characteristics of fuels, using two fuels as the power source of internal combustion engines is becoming more and more popular. Both fuels need to be injected into the cylinder with the help of injectors to burn and provide power. In the prior art, the injectors that meet the independent injection of two fuels are either two completely independent injectors installed on the cylinder head respectively; or two fuels share one injector, such as the patent "Marine Medium and High Speed ​​Oil and Gas Dual Electronic Control Dual Fuel Engine" with announcement number CN113586232A. However, they only share one body, and the internal structure is still arranged with two nozzles, which is large in size and complex in structure, which also brings difficulties to the design of the cylinder head; or they only use simple mechanical injection instead of electronically controlled injection, and cannot accurately control the injection time and injection amount of the two fuels, thus affecting the performance of the entire engine. At the same time, if the existing single-fuel engines on the market are planned to be replaced with dual-fuel engines, the existing injector technology will also require the replacement of components such as the cylinder head. Especially for large marine engines that have already been installed on ships, replacing the cylinder head is time-consuming and labor-intensive, which is very inconvenient and adds difficulties to the application of dual fuels. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a single-nozzle dual-fuel injector, an engine and a control method. The purpose is that two fuels share one nozzle and can achieve independent injection of two fuels using electronic control. Therefore, the injector can be replaced for engines in use on the market without replacing the cylinder head, which is convenient for upgrading and promoting the popularization and application of dual-fuel engine technology.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a single-nozzle dual-fuel injector, comprising a body that can be mounted on an engine, wherein the bottom end of the body is provided with a first nozzle for injecting fuel into the cylinder of the engine; the upper part of the body is provided with a first oil inlet and a second oil inlet for respectively inputting the first fuel and the second fuel into the body; the first oil inlet is connected to a first valve cavity in the body through a first oil passage; a first needle valve that can slide back and forth is inserted in the first valve cavity, the upper end of the first needle valve is provided with a first control mechanism, the other end of which corresponds to the first nozzle, and is used for the first control mechanism to drive the first needle valve to slide back and forth when , controlling the switch of the first nozzle; a one-way valve is provided on the first oil channel; the second oil inlet is connected to the second valve cavity in the device body, a second needle valve which can slide back and forth is inserted in the second valve cavity, a second control mechanism is provided at one end of the second needle valve, and the other end thereof corresponds to the second nozzle, which is used to control the switch of the second nozzle when the second control mechanism drives the second needle valve to slide back and forth; the second nozzle is arranged in the device body and connected to the second oil channel; the other end of the second oil channel is connected to the first valve cavity; at least a first wiring harness channel is provided in the device body, and the first wiring harness connected to the first control mechanism can extend out of the device body.

[0005] As a further optimization, the first control mechanism includes a first electric cylinder, the telescopic rod of the electric cylinder is connected to the first needle valve, and is used to drive the first needle valve to slide reciprocatingly; the second control mechanism includes a second electric cylinder, the cylinder body of the second electric cylinder is located outside the device body and is fixed to the device body, and the telescopic rod is inserted into the second valve cavity and connected to the second needle valve, and is used to drive the second needle valve to slide reciprocatingly.

[0006] As a further optimization, the first control mechanism includes a first control chamber located at the upper end of the first valve chamber, and a first spring is arranged in the first control chamber for pushing the first needle valve to close the first nozzle; a first pressure relief chamber is arranged above the first control chamber; the two ends of the first control oil channel are respectively connected to the first control chamber and the first pressure relief chamber; the first pressure relief chamber is connected to a first oil return port preset on the outer wall of the body; the end of the first armature of the first solenoid valve located in the body can be slidably inserted into the first pressure relief chamber for controlling the switch of the first oil return port; the first solenoid valve can control the reciprocating sliding of the first armature; the first wiring harness is connected to the first solenoid valve.

[0007] As a further optimization, it also includes a bypass channel; one end of the bypass channel is connected to the first oil channel and is located upstream of the one-way valve, and the other end is connected to the first control chamber; the upper side wall of the first needle valve is in close contact with the inner wall of the body, which is used to seal the joint between the first valve chamber and the first control chamber.

[0008] As a further optimization, the second control mechanism includes a second control chamber; the other end of the second needle valve away from the second nozzle is inserted into the second control chamber, and a second spring is arranged in the second control chamber to push the second needle valve to close the second nozzle; the two ends of the second control oil channel are respectively connected to the second control chamber and the second pressure relief chamber; the second pressure relief chamber is connected to the second oil return port preset on the inner wall of the device body; the end of the second armature of the second solenoid valve located in the device body can be slidably inserted into the second pressure relief chamber to control the switch of the second oil return port; the second solenoid valve can control the reciprocating sliding of the second armature; the second wiring harness is connected to the second solenoid valve through the second wiring harness channel preset in the device body; the second needle valve is clearance-matched with the side wall of the device body.

[0009] As a further optimization, the device body includes a nozzle at the lower end; the first valve chamber, the first needle valve and the first spring are all arranged in the nozzle, and the first nozzle is the nozzle at the lower end of the nozzle; the upper end of the nozzle abuts the middle block, and the upper end of the middle block abuts the solenoid valve component one; the first solenoid valve and the first armature are arranged in the solenoid valve component one; the upper end of the solenoid valve component one abuts the device body part two; the lower part of the device body part two, the solenoid valve component one, the middle block and the upper part of the nozzle are all inserted into the clamping cap; the upper part of the clamping cap is threadedly connected to the lower part of the device body part two; the lower part of the nozzle extends out of the clamping cap from the through hole preset at the lower end of the clamping cap; a first recess is provided in the middle of the upper end of the nozzle, which is used to form a spring at the junction of the nozzle and the middle block. The first control chamber is formed; the upper end surface of the intermediate block is provided with a first pit, which is used to form the first pressure relief chamber at the junction of the intermediate block and the solenoid valve assembly one; the side wall of the first pressure relief chamber is provided with a first oil drain hole, which is used to connect with the first oil return port; the first control oil channel is arranged in the intermediate block; the first oil channel passes through the body part two, the solenoid valve assembly one, the intermediate block, the nozzle and is connected with the first valve chamber; the one-way valve is arranged in the intermediate block; the diverter channel is a channel that passes through the upper and lower end surfaces of the intermediate block, and its inlet corresponds to the outlet of the first oil channel on the lower end surface of the solenoid valve assembly, and its outlet corresponds to the first depression at the upper end of the nozzle, which is used to divert the fuel of the first oil channel to the first control chamber.

[0010] As a further optimization, the upper end of the second body part abuts against the first body part, the clamping nut is threadedly connected to the upper end of the second body part, and the lower end of the clamping nut supports the convex ring part preset at the lower end of the body part, which is used to press and seal the joint surface between the second body part and the first body part; the first oil channel runs through the first body part and is connected with the first oil inlet provided at the upper end of the first body part; the second oil inlet is opposite to the second valve cavity; the second valve cavity, the second needle valve and the second spring are all arranged inside the first body part, and the upper end of the first body part is provided with a mounting hole connected to the second valve cavity; the second solenoid valve assembly and the intermediate body are inserted in the mounting hole; the second solenoid valve and the second armature are arranged in the second solenoid valve assembly in; the second solenoid valve is located at the junction of the device body part one and the device body part two; the second wiring harness channel is located in the device body part one, and its outlet is located at the top end of the device body part one; after the first wiring harness channel passes through the device body part two, the intermediate body, the solenoid valve assembly two, and the device body part one, the first outlet at the upper end is located at the top end of the device body part one; inside the device body part one, a flaring area is provided at the upper end of the second valve cavity, which is used to form a second control cavity between the second needle valve and the lower end face of the intermediate body; the upper end face of the intermediate body is provided with a second pit, which is used to form the second pressure relief cavity at the junction of the intermediate block and the solenoid valve assembly two; the second oil drain hole on the side wall of the second pressure relief cavity is connected to the second oil return port set on the side wall of the device body part two.

[0011] The present invention also provides an engine, comprising a single-nozzle dual-fuel injector as described above; the engine controller is respectively connected to the first control mechanism and the second control mechanism by electrical signals, and is used to control the operation of the first control mechanism and the second control mechanism respectively.

[0012] The present invention also provides a control method for a single-nozzle dual-fuel injector, using the single-nozzle dual-fuel injector as described above, comprising the following steps:

[0013] S1: First, the second fuel is injected; the injection pressure of the second fuel is greater than the injection pressure of the first fuel; when the crankshaft of the engine rotates to a predetermined rotation angle φ1, the second control mechanism receives a signal from an external controller and starts to work, the second control mechanism controls the second needle valve to retract, the second fuel flows through the second oil inlet, the second valve cavity, the second oil channel and then enters the first valve cavity, the pressure of the first valve cavity gradually exceeds the pressure of the first oil channel, the one-way valve is closed, and only the second fuel with a relatively high pressure is in the first valve cavity; then, the first control mechanism controls the first needle valve to retract, the first nozzle is opened, and the second fuel is injected at this time;

[0014] S2: When the crankshaft of the engine continues to rotate to a predetermined rotation angle φ2, the external controller sends an electrical signal command to the second control mechanism, and the second control mechanism controls the second needle valve to extend, and the second valve chamber is sealed; therefore, the second fuel cannot continue to enter the first valve chamber, and the second fuel injection stops;

[0015] S3: After the second fuel no longer enters the first valve chamber, the pressure in the first valve chamber drops rapidly. When it is lower than the pressure of the first oil channel, the one-way valve is opened, and the first fuel enters the first valve chamber. At this time, the first fuel is injected;

[0016] S4: When the crankshaft of the engine continues to rotate to a predetermined rotation angle φ3, the external controller sends an electrical signal command to the first control mechanism, and the first control mechanism controls the first needle valve to extend, restores the sealing of the first valve chamber, and stops the first fuel injection;

[0017] S5: Steps S1 to S4 are repeatedly performed, and the first nozzle cyclically injects the second fuel and the first fuel, so that the engine operates under the supply of the two fuels.

[0018] As a further optimization, the second fuel is diesel; the first fuel is methanol; in the step S1, the mixture of the second fuel and fresh air in the cylinder is compression ignited as the engine piston moves upward; in the step S3, the first fuel is sprayed into the cylinder, and the combustion flame in the cylinder ignites the first fuel; in the step S4, after the spraying of the first fuel is stopped, the combustion in the cylinder stops, completing a dual fuel injection cycle.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0020] (1) The dual-fuel injector proposed by the present invention only needs one nozzle, which solves the problem that two injectors cannot be arranged due to the compact position of the engine cylinder head; at the same time, when converting a single-fuel engine to a dual-fuel engine, it is not necessary to redesign and modify the cylinder head and other components. The versatility of parts is improved, which facilitates the conversion of single-fuel engines in use on the market to dual-fuel.

[0021] (2) The single-nozzle dual-fuel injector proposed in the present invention can realize the injection of both fuels using an electronic control method, which makes up for the shortcomings of mechanical injectors that the injection time and injection amount are difficult to control, and at the same time improves the injection accuracy of the two fuels.

[0022] (3) The advantages of setting a one-way valve on the first oil channel of a single-nozzle dual-fuel injector proposed by the present invention are: first, during the injection of the first fuel, the fuel will not flow back from the needle valve chamber to the control chamber due to the pressure relief chamber. Secondly, during the injection of the second fuel, the second fuel is prohibited from entering the first fuel channel, achieving absolute isolation of the two fuels in the injector, and the first oil return port only discharges the first fuel.

[0023] (4) The control mechanisms of the first needle valve and the second needle valve are both three-chamber structures, namely, valve chamber, control chamber and pressure relief chamber control, which can be used for higher oil circuit pressure, meet the matching requirements of high-pressure common rail, and ensure the working performance of the engine.

[0024] In summary, the present invention uses two fuels to share one nozzle, and can achieve independent injection of the two fuels using electronic control. As a result, the injectors of engines currently in use on the market can be replaced without replacing the cylinder head, which facilitates upgrading and transformation, promotes the popularization and application of dual-fuel engine technology, and has a low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of Example 2 of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of Example 3 of the present invention;

[0028] Figure 4 It is a schematic diagram of the cross-sectional structure of the first needle valve of Examples 4 and 5 of the present invention;

[0029] Figure 5 It is a schematic diagram of the external outline structure of Examples 4 and 5 of the present invention;

[0030] Figure 6 It is a schematic cross-sectional structure diagram of the first direction of Example 5 of the present invention;

[0031] Figure 7 It is a schematic cross-sectional structure diagram of the second direction of Example 5 of the present invention;

[0032] Figure 8 It is a schematic cross-sectional structure diagram of the third direction of Example 5 of the present invention;

[0033] Fig. 9 for Figure 8 A partial enlarged view of

[0034] Fig.10 Schematic diagram of the relationship between the crank angle and the injection timing of Examples 1 to 5 of the present invention.

[0035] The corresponding relationship between the technical features and the reference numerals in the figure is: body part 1; body part 2; clamping cap 3; nozzle 4; first needle valve 5; second needle valve 6; solenoid valve assembly 1 7; solenoid valve assembly 2 8; intermediate block 9; one-way valve 10; intermediate body 11; clamping nut 12; first spring 13; second spring 14; slit filter 15; sealing ring 16; sealing ring 17; first armature 18; second armature 19; first oil inlet 111; oil inlet 1 112; oil inlet 2 113; oil inlet 3 114; first oil drain hole 115; first oil return port 116; second Oil inlet 222; second oil drain hole 223; second fuel inlet 224; second nozzle 225; second oil return port 226; first wiring harness channel 1000; second wiring harness channel 2000; first nozzle 300; first oil channel 301; first valve chamber 302; second oil channel 303; second valve chamber 304; first electric cylinder 305; second electric cylinder 306; first control chamber 307; first pressure relief chamber 308; first control oil channel 309; branch channel 310; second control chamber 311; second control oil channel 312; first solenoid valve 313; second solenoid valve 314. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0037] Example 1, please refer to Figure 1 , 10. The present invention provides a technical solution: a single-nozzle dual-fuel injector, comprising a body that can be mounted on an engine, wherein a first nozzle 300 is provided at the bottom of the body for injecting fuel into the cylinder of the engine; a first oil inlet 111 and a second oil inlet 222 are provided at the upper part of the body for respectively inputting the first fuel and the second fuel into the body; the first oil inlet 111 is connected to a first valve cavity 302 in the body through a first oil passage 301; a first needle valve 5 that can slide back and forth is inserted in the first valve cavity 302, a first control mechanism is provided at the upper end of the first needle valve 5, and the other end thereof corresponds to the first nozzle 300, and is used to control the switch of the first nozzle 300 when the first control mechanism drives the first needle valve 5 to slide back and forth; A one-way valve 10 is provided on the first oil channel 301; the second oil inlet 222 is connected to the second valve chamber 304 in the device body through the second oil channel 303, and a second needle valve 6 that can slide back and forth is inserted in the second valve chamber 304, and a second control mechanism is provided at one end of the second needle valve 6, and the other end thereof corresponds to the second nozzle 225, which is used to control the switch of the second nozzle 225 when the second control mechanism drives the second needle valve 6 to slide back and forth; the second nozzle 225 is arranged in the device body and connected to the second oil channel 303; the other end of the second oil channel 303 is connected to the first valve chamber 302;; at least a first wiring harness channel 1000 is provided in the device body, and the first wiring harness connected to the first control mechanism can extend out of the device body.

[0038] The first control mechanism includes a first electric cylinder 305, the telescopic rod of which is connected to the first needle valve 5, and is used to drive the first needle valve 5 to slide back and forth; the second control mechanism includes a second electric cylinder 306, the cylinder body of the second electric cylinder 306 is located outside the device body and is fixed to the device body, and the telescopic rod is inserted into the second valve cavity 304 and connected to the second needle valve 6, and is used to drive the second needle valve 6 to slide back and forth. The two electric cylinders are electrically controlled by the engine controller. The second electric cylinder 306 is arranged outside the device body, and the wiring harness connected to it does not need to pass through the device body.

[0039] To use, follow the steps below.

[0040] S1: First, the second fuel is injected; the injection pressure of the second fuel is greater than the injection pressure of the first fuel; when the crankshaft of the engine rotates to a predetermined angle φ1, the second control mechanism receives a signal from an external controller and starts to work, the second control mechanism controls the second needle valve 6 to retract, the second fuel flows through the second oil inlet 222, the second valve chamber 304, and the second oil channel 303 and then enters the first valve chamber 302, the pressure of the first valve chamber 302 gradually exceeds the pressure of the first oil channel 301, the one-way valve 10 is closed, and only the second fuel with a relatively high pressure is in the first valve chamber 302; then, the first control mechanism controls the first needle valve 5 to retract, the first nozzle 300 is opened, and the second fuel is injected at this time.

[0041] S2: When the crankshaft of the engine continues to rotate to a predetermined rotation angle φ2, the external controller sends an electrical signal instruction to the second control mechanism, and the second control mechanism controls the second needle valve 6 to extend, and the second valve chamber 304 is sealed; therefore, the second fuel cannot continue to enter the first valve chamber 302, and the second fuel injection stops.

[0042] S3: After the second fuel no longer enters the first valve chamber 302, the pressure in the first valve chamber 302 drops rapidly. When it is lower than the pressure in the first oil channel 301, the one-way valve 10 is opened, and the first fuel enters the first valve chamber 302. At this time, the first fuel is injected.

[0043] S4: When the crankshaft of the engine continues to rotate to a predetermined rotation angle φ3, the external controller sends an electrical signal instruction to the first control mechanism, and the first control mechanism controls the first needle valve 5 to extend, restores the sealing of the first valve chamber 302, and stops the first fuel injection.

[0044] S5: Steps S1 to S4 are repeatedly performed, and the first nozzle 300 cyclically injects the second fuel and the first fuel, so that the engine works under the supply of the two fuels.

[0045] Wherein, exemplary, the first fuel is gasoline, and the second fuel is natural gas. The injection pressure of the two fuels, that is, the pressure required for injection in the cylinder of the engine, is relatively low, about 20 MPa.

[0046] It should be noted that, firstly, the body of the device of this embodiment can be split into multiple parts and then assembled, and each part can be manufactured using 3D printing technology. In other words, the manufacture of the body of the device of this embodiment is a prior art, and does not involve the working principle of this embodiment and is not described in detail.

[0047] The advantages of this embodiment are as follows.

[0048] (1) The dual-fuel injector proposed in this embodiment only needs one nozzle 4, which solves the problem that two injectors cannot be arranged due to the compact position of the engine cylinder head; at the same time, when converting a single-fuel engine to a dual-fuel engine, it is not necessary to redesign and modify the cylinder head and other components. The versatility of parts is improved, which facilitates the conversion of single-fuel engines in use on the market to dual-fuel.

[0049] (2) The single-nozzle dual-fuel injector proposed in this embodiment can realize the injection of both fuels using an electronic control method, which makes up for the shortcomings of mechanical injectors that the injection time and injection amount are difficult to control, and at the same time improves the injection accuracy of the two fuels.

[0050] (3) The single-nozzle dual-fuel injector proposed by the present invention prohibits the second fuel from entering the first oil channel 301 during the injection process of the second fuel through the setting of the one-way valve 10, and also prevents the first fuel from participating in the injection.

[0051] In summary, this embodiment uses two fuels to share one nozzle 4, and can achieve independent injection of the two fuels using electronic control, so that the injector can be replaced for the engine in use on the market without replacing the cylinder head, which is convenient for upgrading and transformation, and promotes the promotion and application of dual-fuel engine technology.

[0052] Example 2, please refer to Figure 2 , 10 .

[0053] This embodiment differs from Embodiment 1 in two aspects. First, the second needle valve 6 is arranged horizontally, and the structure is more compact than that of Embodiment 1. It can be seen that, if the space on the engine cylinder head allows, the arrangement angle of the second needle valve 6 can be adjusted as needed, and is not limited to the vertical arrangement of Embodiment 1. Second, the control mechanism of the needle valve is not limited to the electric cylinder of Embodiment 1, and can also be realized by other structures. In this embodiment, preferably, the first control mechanism of the first needle valve 5 adopts a three-chamber structure. Therefore, on the basis of having the advantages of Embodiment 1, this embodiment can be used with higher fuel pressure to ensure the working performance of the engine.

[0054] Among them, the three-chamber structure includes a first control chamber 307 located at the upper end of the first valve chamber 302, and a first spring 13 is arranged in the first control chamber 307 for pushing the first needle valve 5 to close the first nozzle 300; a first pressure relief chamber 308 is arranged above the first control chamber 307; the two ends of the first control oil channel 309 are respectively connected to the first control chamber 307 and the first pressure relief chamber 308; the first pressure relief chamber 308 is connected to the first oil return port 116 preset on the outer wall of the body; the end of the first armature 18 of the first solenoid valve 313 can be slidably inserted into the first pressure relief chamber 308 for controlling the switch of the first oil return port 116; the first solenoid valve 313 can control the reciprocating sliding of the first armature 18; the first wiring harness is connected to the first solenoid valve 313. In addition, it also includes a bypass channel 310; one end of the bypass channel 310 is connected to the upstream of the one-way valve 10 of the first oil channel 301, and the other end is connected to the first control chamber 307; the upper side wall of the first needle valve 5 is in close contact with the side wall of the first valve chamber 302, which is used to seal the joint between the first valve chamber 302 and the first control chamber 307.

[0055] Its working principle includes that in the initial state, that is, the first armature 18 is inserted into the first pressure relief chamber 308, and the first oil return port 116 is in a closed state. The pressure of the first pressure relief chamber 308 and the first control chamber 307 is balanced with the pressure of the first valve chamber 302, and the first needle valve 5 is sealed by the first spring 13. When the first armature 18 retracts, the first oil return port 116 opens, and the pressure of the first pressure relief chamber 308 and the first control chamber 307 is lower than that of the first valve chamber 302. The pressure of the first valve chamber 302 pushes the first needle valve 5 to overcome the elastic force of the first spring 13 and retract, and the first nozzle 300 opens to spray fuel. It can be seen that since the first control oil channel 309 is narrow and has a large flow resistance, most of the fuel is sprayed out through the first nozzle 300.

[0056] Therefore, this embodiment, while having the advantages of the second embodiment, can adapt to the first fuel with a higher injection pressure.

[0057] Example 3, please refer to Figure 3 , 10 .

[0058] The difference between this embodiment and embodiment 2 is that the second needle valve 6 is also controlled by the three-chamber structure, so that compared with embodiment 2, both the first fuel and the second fuel can be applied to higher pressures. The preferred two fuels are: the second fuel is diesel with an injection pressure of 150-200 MPa; the first fuel is methanol with an injection pressure of 50-100 MPa; in step S1, the mixture of the second fuel and fresh air in the cylinder is compression-ignited as the engine piston moves upward; in step S3, the first fuel is sprayed into the cylinder, and the combustion flame in the cylinder ignites the first fuel; in step S4, after the spraying of the first fuel is stopped, the combustion in the cylinder stops, completing a dual-fuel injection cycle. Among them, the control principle of the second needle valve 6 is the same as that of embodiment 2.

[0059] At this time, by setting a one-way valve 10 on the first oil passage 301, during the injection process of the first fuel, the fuel will not flow back from the first valve chamber 302 to the first control chamber 307 due to the pressure relief of the first pressure relief chamber 308. In addition, the second fuel is prohibited from entering the first oil passage 301, achieving absolute isolation of the two fuels in the injector, and the first oil return port 116 only discharges the first fuel.

[0060] Therefore, compared with Example 2, in this embodiment, both fuels can use high-pressure liquid fuels, both can meet the matching requirements of the high-pressure common rail, and the power performance of the engine is better.

[0061] Example 4, please refer to Figure 4-10 .

[0062] Compared with Example 2, although the body can be manufactured by existing 3D printing technology or precision casting technology, the internal structural features of the body are more, manufacturing is more inconvenient, and the cost is higher. This embodiment aims to have the effects of Example 2 while overcoming the manufacturing problem of the body. Therefore, the body is split at least at the first needle valve 5 corresponding to the body to facilitate separate manufacturing and reduce costs.

[0063] Thus, the device body includes a nozzle 4 at the lower end; the first valve chamber 302, the first needle valve 5 and the first spring 13 are all arranged in the nozzle 4, and the first nozzle 300 is the nozzle at the lower end of the nozzle 4; the upper end of the nozzle 4 abuts the middle block 9, and the upper end of the middle block 9 abuts the solenoid valve assembly 7; the first solenoid valve 313 and the first armature 18 are arranged in the solenoid valve assembly 7; the upper end of the solenoid valve assembly 7 abuts the device body 2; the lower part of the device body 2, the solenoid valve assembly 7, the middle block 9 and the upper part of the nozzle 4 are all inserted into the clamping cap 3; the upper part of the clamping cap 3 is threadedly connected with the lower part of the device body 2; the lower part of the nozzle 4 extends out of the clamping cap 3 from the through hole preset at the lower end of the clamping cap 3; a first depression is provided in the middle of the upper end of the nozzle 4, which is used to form the first control chamber 3 at the junction of the nozzle 4 and the middle block 9. 07; a first pit is provided on the upper end surface of the intermediate block 9, which is used to form the first pressure relief chamber 308 at the junction of the intermediate block 9 and the solenoid valve assembly 7; a first oil drain hole 115 is provided on the side wall of the first pressure relief chamber 308, which is used to connect to the first oil return port 116; the first control oil channel 309 is arranged in the intermediate block 9; the first oil channel 301 passes through the body part 2, the solenoid valve assembly 7, the intermediate block 9, the nozzle 4 and is connected with the first valve chamber 302; the one-way valve 10 is arranged in the intermediate block 9; the diverter channel 310 is a channel passing through the upper and lower end surfaces of the intermediate block 9, and its inlet corresponds to the outlet of the first oil channel 301 on the lower end surface of the solenoid valve assembly 7, and its outlet corresponds to the first depression at the upper end of the nozzle 4, which is used to divert the fuel of the first oil channel 301 to the first control chamber 307.

[0064] It can be seen that in this embodiment, the lower part of the body is divided into the body part 2, the middle block 9, and the nozzle 4, and the three parts are fixed together by the clamping cap 3. The first solenoid valve 313 is arranged between the body part 2 and the middle block 9, and the first needle valve 5 is arranged in the nozzle 4. The nozzle 4 goes deep into the cylinder to inject fuel. Through the above splitting, it is convenient to manufacture each component separately and then assemble them, which reduces the manufacturing cost.

[0065] Example 5, please refer to Figure 4-10 .

[0066] In this embodiment, on the basis of the fourth embodiment, the body is completely manufactured by separate parts and then assembled, which is suitable for simple mechanical processing to form. That is to say, the body part corresponding to the second needle valve 6 is also manufactured by separate parts. At the same time, the two fuels also meet the higher pressure requirements, so this embodiment also has the advantages of the third embodiment.

[0067] Thus, the upper end of the body part 2 abuts against the body part 1, the clamping nut 12 is threadedly connected to the upper end of the body part 2, and the lower end of the clamping nut 12 supports the preset convex ring part at the lower end of the body part 1, which is used to press and seal the joint surface between the body part 2 and the body part 1; the first oil channel 301 runs through the body part 1, and is connected to the first oil inlet 111 arranged at the upper end of the body part 1; the second oil inlet 222 is horizontally opposite to the first valve cavity 302, and is connected to the second oil inlet 222 arranged on the upper side of the body part 1; the second valve cavity 304, the second needle valve 6 and the second spring 14 are all arranged inside the body part 1, and the upper end of the body part 1 is provided with a mounting hole connected to the second valve cavity 304; the solenoid valve assembly 28 and the intermediate body 11 are inserted in the mounting hole; the second solenoid valve 314 and the second armature 19 are arranged in the solenoid valve assembly 28; The second solenoid valve 314 is located at the junction of the device body 1 and the device body 2; the second wiring harness channel 2000 is located in the device body 1, and the second outlet at its upper end is located at the top of the device body 1; after the first wiring harness channel 1000 passes through the device body 2, the intermediate body 11, the solenoid valve assembly 28, and the device body 1, the first outlet at its upper end is located at the top of the device body 1; inside the device body 1, a second valve cavity 304 is provided with an expansion area at the upper end, which is used to form a second control cavity 311 between the second needle valve 6 and the lower end surface of the intermediate body 11; the upper end surface of the intermediate body 11 is provided with a second pit, which is used to form the second pressure relief cavity at the junction of the intermediate block 9 and the solenoid valve assembly 28; one end of the second oil leakage channel is connected to the second oil leakage hole 223 on the side wall of the second pressure relief cavity, and its middle part passes through the intermediate body 11 and the device body 2, and is connected to the second oil return port 226 set on the side wall of the device body 2.

[0068] It can be seen that the present embodiment has completely disassembled the body, and from top to bottom, it is divided into body part 1, second solenoid valve 314, intermediate body 11, body part 2, second needle valve 6, first solenoid valve 313, intermediate block 9, nozzle 4, and first needle valve 5; then body part 1 and body part 2 are fixed together by a compression screw, and body part 2 and nozzle 4 are fixed together by a compression cap 3, so that the body is assembled, and the second solenoid valve 314, second needle valve 6, first solenoid valve 313, and first needle valve 5 are all installed inside the body. Through the above disassembly, it is convenient to manufacture each component separately, and then assemble them, which reduces the manufacturing cost.

[0069] At this point, the injector of this embodiment includes: a body part 1 for the first fuel, a body part 2 for the second fuel, a clamping cap 3, a nozzle 4, a first needle valve 5 constituting a needle valve pair with the nozzle 4, a second needle valve 6 constituting a needle valve pair with the body part 22, an electromagnetic valve assembly 2 8 installed at the upper end of the body part 2, and an electromagnetic valve assembly 7 installed at the lower end of the body part 2.

[0070] The middle block 9 connects and fixes the body part 2, the solenoid valve assembly 1 7 and the nozzle 4 together through the compression cap 3, and provides sealing pressure for the sealing surface.

[0071] A first control chamber 307 for the first fuel is formed between the middle block 9, the first needle valve 5 and the spring seat; a first pressure relief chamber 308 for the first fuel is formed between the middle block 9 and the solenoid valve assembly 7; and a first valve chamber 302 is formed between the nozzle 4 and the first needle valve 5.

[0072] The first fuel enters from the first fuel inlet 111 on the first body, and is divided into two paths at the middle block 9: fuel inlet 1 112 and fuel inlet 2 113. The fuel entering from fuel inlet 1 112 enters the first control chamber 307, and then enters the first pressure relief chamber 308 through fuel inlet 3 114; the fuel entering from fuel inlet 2 113 enters the first valve chamber 302 through the one-way valve 10.

[0073] When it is necessary to start spraying the first fuel, the external controller sends an electrical signal to the solenoid valve assembly 7 to instruct it to start powering on, the first armature 18 of the solenoid valve is moved, the sealed first pressure relief chamber 308 is opened, and the fuel in the pressure relief chamber is released through the first oil drain hole 115, thereby affecting the control chamber pressure, causing the pressure in the first control chamber 307 to be less than the pressure in the first valve chamber 302, that is, the pressure in the first valve chamber 302 is greater than the pressure in the first control chamber 307 + the pressure in the first spring 13, so the first needle valve 5 moves toward the first control chamber 307 under the action of the unbalanced force, and the first nozzle 300 is opened. At this time, the nozzle 4 sprays the first fuel.

[0074] The setting of the one-way valve 10 can realize that the fuel can only flow in one direction, that is, the first fuel can only flow from the second oil inlet 113 to the first valve chamber 302, and the fuel will not flow back from the first valve chamber 302 to the first control chamber 307 due to the pressure relief of the first pressure relief chamber 308.

[0075] The first fuel flowing out of the first pressure relief hole is led out of the injector through the first oil return port 116, and the first oil return port 116 is arranged on the body part 1.

[0076] The injector proposed in this embodiment is also integrated with a first fuel filter, that is, after entering the oil passage through the first oil inlet 111 , the fuel first passes through the slit filter 15 and then enters the nozzle 4 .

[0077] The injector also includes an intermediate body 11, a clamping nut 12, a second oil inlet 222, a second oil return port 226, a second oil drain hole 223, a second fuel oil inlet 224, and a second nozzle 225. The intermediate body 11 connects and fixes the body part 1, the body part 2, and the solenoid valve assembly 2 8 together through the clamping cap 3, and provides sealing pressure for the sealing surface. The intermediate body 11, the second needle valve 6, and the spring seat form a second control chamber 311, a second needle valve 6 chamber is formed between the second needle valve 6 and the body part 2, and a second fuel pressure relief chamber is formed between the intermediate body 11 and the solenoid valve assembly 2 8.

[0078] The second fuel enters the second valve chamber 304 from the second oil inlet 222 on the body part 2, flows through the gap in the side wall of the second needle valve 6 to reach the second control chamber 311, and then enters the second pressure relief chamber through the second fuel oil inlet 224. The oil passage diameter of the second fuel oil inlet 224 set here is smaller than the oil passage diameter of the second oil inlet 222. When it is necessary to start injecting the second fuel, the external controller sends an electrical signal to the solenoid valve assembly 28 to instruct it to start powering on, the second armature 19 of the solenoid valve is moved, the sealed second pressure relief chamber is opened, and the high-pressure fuel is relieved through the second fuel oil drain hole.

[0079] The second fuel flowing out of the second fuel drain hole is discharged out of the injector through the second oil return port 226 .

[0080] The opening conditions of the second needle valve 6 are as follows: since the second oil inlet 222 will continuously supply high-pressure fuel to the second control chamber 311; and the oil passage diameter of the second fuel oil inlet 224 is smaller than the oil passage diameter of the second oil inlet 222; and since the opening time of the second pressure relief chamber controlled by the solenoid valve is relatively short, the pressure of the needle valve chamber near the seal between the second needle valve 6 and the body 2 is very little affected by the pressure relief of the second pressure relief chamber of the fuel (very little). The pressure of the second control chamber 311 is reduced due to the direct cause of the fuel pressure relief, which is less than the pressure of the second valve chamber 304, so the pressure of the second valve chamber 304>the pressure of the second control chamber 311+the pressure of the second spring 14, and the second needle valve 6 moves toward the second control chamber 311 under the action of the unbalanced force, and the second nozzle 225 opens, so that the second fuel enters the first valve chamber 302 shared with the first fuel through the second nozzle 225.

[0081] The present embodiment also includes a wiring harness hole 7 for the solenoid valve assembly 1 and a wiring harness hole 8 for the solenoid valve assembly 2, which are connected to an external controller for controlling the operation of the solenoid valve assembly and further controlling the operation of the injector.

[0082] A sealing ring 16 and a sealing ring 17 for sealing the fuel are arranged on the body part 1 and the body part 2, and are used to seal the leakage of the first fuel and the second fuel.

[0083] The second fuel described in this embodiment is preferably a high-pressure, compression-ignited fuel in the engine cylinder, such as diesel (pressure is generally 150-200 MPa), as an auxiliary fuel for the engine power. The first fuel described in this embodiment is preferably a fuel with normal pressure, such as methanol, ethanol, etc. (pressure is generally 50-100 MPa), which can be ignited or burned by the second fuel and used as the main fuel for the engine power.

[0084] The present invention also includes a method for controlling the injection of two fuels. Under the action of an external controller, the two fuels work according to the following method:

[0085] Take a fuel injection working cycle of the engine as an example: first, the second fuel is injected, that is, at a certain moment (crankshaft angle φ1), the second fuel is first injected into the cylinder, and the mixture of the second fuel and fresh air in the cylinder is compressed and ignited as the engine piston moves upward; then at a certain moment (crankshaft angle φ2), the injection of the second fuel is stopped, and the first fuel is injected into the cylinder at this time, and the combustion flame in the cylinder ignites the first fuel; when the engine continues to run until a certain moment (crankshaft angle φ3), the injection of the first fuel is stopped. The above process completes a fuel injection cycle.

[0086] like Fig.10 When the engine runs to the crankshaft angle φ1, the solenoid valve assembly 2 8 receives the signal from the external controller and starts to work. After the second fuel with relatively high pressure enters the first valve chamber 302, the pressure of the first valve chamber 302 gradually exceeds the pressure of the oil port 2, and the one-way valve 10 is closed. Only the second fuel with relatively high pressure is in the first valve chamber 302. At the same time, the first needle valve 5 is in the open state, and the nozzle 4 sprays the second fuel.

[0087] When the engine runs to the crankshaft angle φ2, the external controller sends an electrical signal to the solenoid valve assembly 28 to instruct it to cut off the power, the second armature 19 of the solenoid valve is reset, and the second needle valve 6 resumes sealing, so the second fuel cannot enter the first valve chamber 302 shared with the first fuel, and the second fuel injection stops.

[0088] After the second fuel no longer enters the shared first valve chamber 302, the pressure in the first valve chamber 302 drops rapidly. When it is lower than the pressure of the second oil inlet 113, the one-way valve 10 is opened again, and the first fuel enters the first valve chamber 302. At this time, the nozzle 4 sprays the first fuel.

[0089] When the engine continues to run to the crankshaft angle φ3, the external controller sends an electrical signal to the solenoid valve assembly 7 to instruct it to cut off the power, the first armature 18 of the solenoid valve is reset, and the first needle valve 5 resumes the sealing between the first valve chamber 302 and the nozzle 4 under the action of the spring, stopping the first fuel injection.

[0090] In summary, the single-nozzle dual-fuel injector proposed by the present invention has the following advantages:

[0091] (1) The dual-fuel injector proposed by the present invention only needs one nozzle 4, which solves the problem that two injectors cannot be arranged due to the compact position of the engine cylinder head; at the same time, when converting a single-fuel engine to a dual-fuel engine, it is not necessary to redesign and modify the cylinder head and other components. The versatility of parts is improved, which facilitates the conversion of single-fuel engines in use on the market to dual-fuel.

[0092] (2) The single-nozzle dual-fuel injector proposed in the present invention can realize the injection of both fuels using an electronic control method, which makes up for the shortcomings of mechanical injectors that the injection time and injection amount are difficult to control, and at the same time improves the injection accuracy of the two fuels.

[0093] (3) The advantages of setting a one-way valve 10 on the first oil passage 301 of the single-nozzle dual-fuel injector proposed by the present invention are as follows: First, during the injection of the first fuel, the fuel will not flow back from the needle valve chamber to the control chamber due to the pressure relief of the pressure relief chamber. Second, during the injection of the second fuel, the second fuel is prohibited from entering the first fuel passage, thereby achieving absolute isolation of the two fuels in the injector, and the first oil return port 116 only discharges the first fuel.

[0094] (4) The control mechanisms of the first needle valve 5 and the second needle valve 6 are both three-chamber structures, namely, valve chamber, control chamber and pressure relief chamber control, which can be applied to higher oil circuit pressure, meet the matching requirements of high-pressure common rail, and ensure the working performance of the engine.

[0095] This embodiment uses two fuels to share one nozzle 4, and can realize independent injection of the two fuels using electronic control, so that the injector can be replaced for the engine in use on the market without replacing the cylinder head, which is convenient for upgrading and transformation, promotes the promotion and application of dual-fuel engine technology, and has low production cost.

[0096] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various combinations, changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and these variations should all be considered to be included within the scope of the present application; the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A single-nozzle dual-fuel injector, comprising a body that can be mounted on an engine, wherein a first nozzle (300) is provided at the bottom end of the body for injecting fuel into a cylinder of the engine; characterized in that: The upper part of the device body is provided with a first oil inlet (111) and a second oil inlet (222) for respectively inputting the first fuel and the second fuel into the device body; the first oil inlet (111) is communicated with the first valve chamber (302) in the device body through a first oil passage (301); a first needle valve (5) which can slide back and forth is inserted in the first valve chamber (302); a first control mechanism is provided at the upper end of the first needle valve (5), and the other end of the first needle valve (5) corresponds to the first nozzle (300) and is used for controlling the opening and closing of the first nozzle (300) when the first control mechanism drives the first needle valve (5) to slide back and forth; a one-way valve (10) is provided on the first oil passage (301); The second oil inlet (222) is communicated with a second valve chamber (304) in the body; a second needle valve (6) that can slide back and forth is inserted in the second valve chamber (304); a second control mechanism is provided at one end of the second needle valve (6); the other end of the second needle valve (6) corresponds to the second nozzle (225) and is used to control the opening and closing of the second nozzle (225) when the second control mechanism drives the second needle valve (6) to slide back and forth; the second nozzle (225) is arranged in the body and communicated with the second oil channel (303); the other end of the second oil channel (303) is communicated with the first valve chamber (302); At least a first harness channel (1000) is provided in the device body, and a first harness for connecting the first control mechanism can extend out of the device body.

2. A single-nozzle dual-fuel injector according to claim 1, characterized in that: The first control mechanism comprises a first electric cylinder (305), the telescopic rod of the electric cylinder being connected to the first needle valve (5) and being used for driving the first needle valve (5) to slide back and forth; The second control mechanism comprises a second electric cylinder (306), the cylinder body of the second electric cylinder (306) is located outside the device body and is fixedly connected to the device body, and the telescopic rod of the second electric cylinder (306) is inserted into the second valve cavity (304) and connected to the second needle valve (6) for driving the second needle valve (6) to slide back and forth.

3. A single nozzle dual fuel injector according to claim 1, characterized in that: The first control mechanism comprises a first control chamber (307) located at the upper end of the first valve chamber (302), wherein a first spring (13) is arranged in the first control chamber (307) for pushing the first needle valve (5) to close the first nozzle (300); a first pressure relief chamber (308) is arranged above the first control chamber (307); two ends of a first control oil passage (309) are respectively connected to the first control chamber (307) and the first pressure relief chamber (308); the first pressure relief chamber (308) is connected to a first oil return port (116) preset on the outer wall of the body; the end of a first armature (18) of a first solenoid valve (313) located in the body can be slidably inserted into the first pressure relief chamber (308) for controlling the switch of the first oil return port (116); the first solenoid valve (313) can control the reciprocating sliding of the first armature (18); and the first wiring harness is connected to the first solenoid valve (313).

4. A single-nozzle dual-fuel injector according to claim 3, characterized in that: It also includes a flow diversion channel (310); one end of the flow diversion channel (310) is connected to the first oil channel (301) and is located upstream of the one-way valve (10), and the other end of the flow diversion channel (310) is connected to the first control chamber (307); The upper side wall of the first needle valve (5) is in close contact with the inner wall of the body, and is used to seal the joint between the first valve chamber (302) and the first control chamber (307).

5. A single-nozzle dual-fuel injector according to claim 4, characterized in that: The second control mechanism comprises a second control chamber (311) connected to the second valve chamber (304); the other end of the second needle valve (6) away from the second nozzle (225) is inserted into the second control chamber (311), and a second spring (14) is arranged in the second control chamber (311) to push the second needle valve (6) to close the second nozzle (225); the two ends of the second control oil channel (312) are respectively connected to the second control chamber (311) and the second pressure relief chamber; the second pressure relief chamber is connected to the second oil return port (226) preset on the outer wall of the body; the end of the second armature (19) of the second solenoid valve (314) located in the body can be slidably inserted into the second pressure relief chamber to control the opening and closing of the second oil return port (226); the second solenoid valve (314) can control the reciprocating sliding of the second armature (19); the second wiring harness is connected to the second solenoid valve (314) through the second wiring harness channel (2000) preset in the body; the second needle valve (6) is clearance-matched with the side wall of the body.

6. A single-nozzle dual-fuel injector according to claim 5, characterized in that: The device body comprises a nozzle (4) at the lower end; the first valve chamber (302), the first needle valve (5) and the first spring (13) are all arranged in the nozzle (4), and the first nozzle (300) is the nozzle at the lower end of the nozzle (4); the upper end of the nozzle (4) abuts against the middle block (9), and the upper end of the middle block (9) abuts against the electromagnetic valve assembly (7); the first electromagnetic valve (313) and the first armature (18) are arranged in the electromagnetic valve assembly (7); the upper end of the electromagnetic valve assembly (7) abuts against the device body part (2); the lower part of the device body part (2), the electromagnetic valve assembly (7), the middle block (9) and the upper part of the nozzle (4) are all inserted into the clamping cap (3); the upper part of the clamping cap (3) is threadedly connected to the lower part of the device body part (2); the lower part of the nozzle (4) extends out of the clamping cap (3) from a through hole preset at the lower end of the clamping cap (3); A first recess is provided in the middle of the upper end of the nozzle (4), which is used to form the first control chamber (307) at the junction of the nozzle (4) and the middle block (9); The upper end surface of the intermediate block (9) is provided with a first recessed hole for forming the first pressure relief chamber (308) at the junction of the intermediate block (9) and the solenoid valve assembly (7); the side wall of the first pressure relief chamber (308) is provided with a first oil drain hole (115) for communicating with the first oil return port (116); the first control oil passage (309) is arranged in the intermediate block (9); The first oil passage (301) passes through the second body part (2), the first solenoid valve assembly (7), the middle block (9), the nozzle (4) and is in communication with the first valve chamber (302); The one-way valve (10) is arranged in the middle block (9); the diverter channel (310) is a channel that passes through the upper and lower end surfaces of the middle block (9), the inlet of which corresponds to the outlet of the first oil channel (301) on the lower end surface of the first solenoid valve assembly (7), and the outlet of which corresponds to the first recess at the upper end of the nozzle (4), and is used to divert the fuel in the first oil channel (301) to the first control chamber (307).

7. A single-nozzle dual-fuel injector according to claim 6, characterized in that: The upper end of the second body part (2) abuts against the first body part (1), the clamping nut (12) is threadedly connected to the upper end of the second body part (2), and the lower end of the clamping nut (12) supports the convex ring portion preset at the lower end of the first body part (1) to press the joint surface of the second body part (2) and the first body part (1) to seal; The first oil passage (301) passes through the body part one (1) and is in communication with a first oil inlet (111) disposed at the upper end of the body part one (1); The second oil inlet (222) is directly opposite to the second valve cavity (304); the second valve cavity (304), the second needle valve (6) and the second spring (14) are all arranged inside the body part 1 (1); the upper end of the body part 1 (1) is provided with a mounting hole connected to the second valve cavity (304); the solenoid valve assembly 2 (8) and the intermediate body (11) are inserted into the mounting hole; the second solenoid valve (314) and the second armature (19) are arranged in the solenoid valve assembly The second solenoid valve (314) is located at the junction of the device body part 1 (1) and the device body part 2 (2); the second wiring harness channel (2000) is located in the device body part 1 (1), and its outlet is located at the top end of the device body part 1 (1); after the first wiring harness channel (1000) passes through the device body part 2 (2), the intermediate body (11), the solenoid valve assembly 2 (8), and the device body part 1 (1), its upper end first outlet is located at the top end of the device body part 1 (1); Inside the body part 1 (1), a second valve cavity (304) is provided with an expansion area at the upper end thereof, for forming a second control cavity (311) between the second needle valve (6) and the lower end surface of the intermediate body (11); The upper end surface of the intermediate body (11) is provided with a second recessed pit for forming the second pressure relief chamber at the junction of the intermediate block (9) and the second solenoid valve assembly (8); The second oil drain hole (223) on the side wall of the second pressure relief chamber is in communication with the second oil return port (226) provided on the side wall of the second (2) body member.

8. An engine, characterized in that; It comprises a single-nozzle dual-fuel injector as described in any one of claims 1-7; the engine controller is connected to the first control mechanism and the second control mechanism with electrical signals respectively, and is used to control the operation of the first control mechanism and the second control mechanism respectively.

9. A control method for a single-nozzle dual-fuel injector, characterized in that: Using the single nozzle dual fuel injector as claimed in any one of claims 1 to 7 comprises the following steps: S1: First, the second fuel is injected; the injection pressure of the second fuel is preset to be greater than the injection pressure of the first fuel; when the crankshaft of the engine rotates to a predetermined rotation angle φ1, the second control mechanism receives a signal from an external controller and starts to work, the second control mechanism controls the second needle valve (6) to retract, the second fuel flows through the second oil inlet (222), the second valve chamber (304), and the second oil channel (303) and then enters the first valve chamber (302), the pressure of the first valve chamber (302) gradually becomes greater than the pressure of the first oil channel (301), the one-way valve (10) is closed, and only the second fuel with a relatively high pressure is in the first valve chamber (302); then, the first control mechanism controls the first needle valve (5) to retract, the first nozzle (300) is opened, and the second fuel is injected at this time; S2: When the crankshaft of the engine continues to rotate to a predetermined rotation angle φ2, the external controller sends an electrical signal command to the second control mechanism, and the second control mechanism controls the second needle valve (6) to extend, and the second valve chamber (304) is sealed; therefore, the second fuel cannot continue to enter the first valve chamber (302), and the second fuel injection stops; S3: After the second fuel no longer enters the first valve chamber (302), the pressure in the first valve chamber (302) drops rapidly. When the pressure is lower than the pressure in the first oil passage (301), the one-way valve (10) is opened, and the first fuel enters the first valve chamber (302). At this time, the first fuel is injected; S4: When the crankshaft of the engine continues to rotate to a predetermined rotation angle φ3, the external controller sends an electrical signal command to the first control mechanism, and the first control mechanism controls the first needle valve (5) to extend, restores the sealing of the first needle valve chamber (302), and stops the first fuel injection; S5: Steps S1 to S4 are repeatedly executed, and the first nozzle (300) cyclically injects the second fuel and the first fuel, so that the engine operates under the supply of the two fuels.

10. The control method of a single-nozzle dual-fuel injector according to claim 9, characterized in that: The second fuel is diesel; the first fuel is methanol; In step S1, the mixture of the second fuel and fresh air in the cylinder is compression-ignited as the engine piston moves upward; in step S3, the first fuel is sprayed into the cylinder, and the combustion flame in the cylinder ignites the first fuel; in step S4, after the spraying of the first fuel stops, the combustion in the cylinder stops, completing a dual-fuel injection cycle.

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