High-pressure common-rail in-cylinder methanol direct injection fuel injector

Abstract

The invention relates to the field of methanol engine electronic control oil injectors, and provides a high-pressure common-rail in-cylinder direct injection methanol oil injector which comprises an electromagnetic valve assembly, an oil way control assembly, an oil nozzle assembly and a shell. Wherein the electromagnetic valve assembly converts an electric signal into electromagnetic force, so that the flow of fuel oil is controlled by the control matching part; the oil way control assembly controls the needle valve to move up and down through the plunger structure, so that the methanol oil injector is opened and closed. The oil nozzle assembly is used for enabling the methanol oil injector to stretch into an engine and injecting fuel oil through an oil nozzle, and the fuel oil is evenly mixed with air. The shell is mainly used for connecting all the assemblies, and the stability of the whole oil sprayer is guaranteed. Through the structural design of the coupling surface of the armature core shaft and the plunger sleeve, the cavitation problem of a control matching part during high-pressure low-viscosity unsteady-state flowing is solved, the service life of the methanol fuel injector is greatly prolonged, the high response speed of the methanol fuel injector is guaranteed, and the reliability of the methanol fuel injector is improved. And a powerful technical support is provided for the development of the high-pressure common rail in-cylinder methanol direct injection oil injector.

Description

Technical Field

[0001] The invention relates to the field of electronically controlled fuel injectors for methanol engines, and in particular to a high-pressure common rail in-cylinder direct-injection methanol fuel injector. Technical Background

[0002] The direct injection methanol fuel injector is one of the key components in modern methanol engine technology and the core key technology for realizing efficient and green fuel engines. The fuel injector is a system with high-frequency transient phase coupling and ultra-precise structure of multiple physical fields such as electricity, magnetism, machine and fluid. As the actuator and key component of the fuel injection system, this system has a great influence on the power, fuel economy and emission performance of the methanol engine. In order to enable the engine to obtain better performance, the requirements for the response speed and repeatability of the fuel injector are constantly improving, and its structural form is also constantly innovating. However, due to the unique physical and chemical properties of methanol fuel, the viscosity is low and it is corrosive, which easily causes the surface of the ball valve component inside the methanol fuel injector to fail due to cavitation of high-pressure low-viscosity non-steady-state flow, which seriously reduces the service life of the methanol fuel injector. Therefore, in view of the above problems, the present invention provides a high-pressure common rail direct injection methanol fuel injector. Summary of the invention

[0003] In view of the above technical problems, the purpose of the present invention is to provide a high-pressure common rail in-cylinder direct injection methanol injector, which can effectively solve the above-mentioned ball valve failure problem, increase the service life of the methanol injector, and reduce the complexity of the nozzle.

[0004] To achieve the above, the technical solution adopted by the present invention is: to provide a high-pressure common rail in-cylinder direct injection methanol injector, which includes a solenoid valve assembly, an oil circuit control assembly, a nozzle assembly and a housing. The solenoid valve assembly converts the electrical signal into electromagnetic force through the command of the engine control unit to realize the control of the flow of fuel by the control pair; the oil circuit control assembly controls the up and down movement of the needle valve through the plunger structure to achieve the opening and closing of the methanol injector; the nozzle assembly is used to extend the methanol injector into the engine cylinder, and evenly spray the fuel into the combustion chamber through the spray hole to achieve the purpose of evenly mixing with the air in the cylinder; the housing mainly connects the various components to ensure the stability of the entire injector.

[0005] The oil circuit control component mainly includes a nut, a plunger sleeve, a control plunger, and a plunger spring, wherein the outside of the nut is fixed to the housing by a threaded connection, and a flow channel is provided inside the plunger sleeve to allow high-pressure fuel to pass through and connect to the upper end of the control plunger, with a plunger control chamber left in the middle to provide downward pressure for the control plunger; the return spring resets the control plunger when the injector is closed.

[0006] The solenoid valve assembly mainly includes a solenoid valve, an armature, a return spring, and an armature spring, wherein the armature serves as a displacement mechanism to control the conversion of high-pressure fuel and low-pressure fuel, and to release pressure in the control chamber, an upward thrust is generated by the oil pressure on the needle valve; the armature is composed of an armature plate and an armature core shaft, and adopts a split structure design, the two are assembled by interference fitting, and the lower end of the armature core shaft adopts a multi-curved surface configuration design, which fits tightly with the upper inclined surface of the plunger sleeve; the armature spring is assembled with the lower end of the armature, and the return spring is used to reset the armature.

[0007] The second conical surface at the lower end of the armature core shaft is coupled with the inclined surface at the upper end of the plunger sleeve, and the length of the coupling surface is L, and the value range of L is 7mm≤L≤8mm.

[0008] The contact length of the coupling surface at the lower end of the armature core shaft is a, the length of the coupling surface at the upper end of the plunger sleeve is b, and the value range of b / a is 1.5≤b / a≤1.7.

[0009] The lower end of the armature core shaft adopts a multi-curved surface configuration design, the angle between the first cone surface and the center line of the armature core shaft is α, and its value range is 45.6°≤α≤50.5°, and the angle between the second cone surface and the center line of the armature core shaft is 29.3°≤β≤31.5°.

[0010] The fuel nozzle mainly includes a needle valve, a fuel nozzle, and a fuel nozzle housing, wherein the needle valve is connected with a control plunger to control the opening and closing of the fuel injector; a fuel injection hole is provided at the lower end of the fuel nozzle, through which the fuel is evenly sprayed into the combustion chamber to achieve the purpose of evenly mixing with the air in the cylinder; the fuel nozzle housing connects the fuel nozzle and the fuel injector housing.

[0011] The beneficial effects of the present invention are as follows: by adopting a multi-curved surface configuration design for the lower end of the armature core shaft and a structural design of the coupling surface between the lower end of the armature core shaft and the plunger sleeve, the cavitation problem of the control couple in high-pressure, low-viscosity non-steady-state flow is solved, the service life of the methanol injector is greatly extended, a high response speed of the methanol injector is ensured, and a strong technical support is provided for the development of injectors for high-pressure common rail direct-injection methanol engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural cross-sectional view of a high-pressure common rail in-cylinder direct injection methanol injector; Figure 2 This is a cross-sectional view of the armature of a high-pressure common rail in-cylinder direct injection methanol injector; Figure 3 This is a partial enlarged view of the high-pressure common rail in-cylinder direct injection methanol injector; In the figure: 1. return spring; 2. armature core shaft; 3. armature plate; 4. plunger sleeve; 5. housing; 6. solenoid valve; 7. armature spring; 8. nut; 9. control plunger; 10. plunger spring; 11. needle valve; 12 oil nozzle. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] The present invention will be described below in conjunction with the accompanying drawings. Figure 1-3 As shown, the present invention provides a high-pressure common rail in-cylinder direct injection methanol injector, which includes a solenoid valve assembly, an oil circuit control assembly, a nozzle assembly and a housing; the solenoid valve assembly converts an electrical signal into an electromagnetic force through an instruction of an engine control unit (ECU) to realize the control of the flow of fuel by the control pair; the oil circuit control assembly controls the up and down movement of the needle valve through a plunger structure to achieve the opening and closing of the methanol injector; the nozzle assembly is used to extend the methanol injector into the engine cylinder and evenly spray the fuel into the combustion chamber through the spray hole to achieve the purpose of evenly mixing with the air in the cylinder; the housing mainly connects the various components to ensure the stability of the entire injector.

[0015] like Figure 1 As shown, the solenoid valve assembly mainly includes a solenoid valve 6, an armature, a return spring 1 and an armature spring 7, wherein the armature is used as a displacement mechanism to control the conversion of high-pressure fuel and low-pressure fuel, and to release the pressure in the control chamber, the needle valve 11 is made to generate an upward thrust through the oil pressure; the armature is composed of an armature plate 3 and an armature core shaft 2, and adopts a split structure design, and the two are assembled by interference fitting, and the lower end of the armature core shaft 2 adopts a multi-curved surface configuration design, which fits tightly with the upper end inclined surface of the plunger sleeve 4; the armature spring 7 is assembled with the lower end of the armature; the return spring 1 is used to reset the armature. The oil circuit control assembly mainly includes a nut 8, a plunger sleeve 4, a control plunger 9, and a plunger spring 10, wherein the nut 8 is fixed to the housing by a threaded connection on the outside, and a flow channel is provided inside the plunger sleeve 4, so that the high-pressure fuel passes through and is connected to the upper end of the control plunger 9, and a plunger control chamber is left in the middle to provide downward pressure for the control plunger 9; the plunger spring 10 resets the control plunger 9 when the injector is closed. The nozzle assembly mainly includes a needle valve 11, a nozzle 12, and a nozzle housing, wherein the needle valve 11 is connected to the control plunger 9 to control the opening and closing of the injector fuel injection; a spray hole is provided at the lower end of the nozzle 12, through which the fuel is evenly sprayed into the combustion chamber to achieve the purpose of evenly mixing with the air in the cylinder; the nozzle housing connects the nozzle and the injector housing.

[0016] In the initial state, the injector does not receive the driving electrical signal from the engine ECU, the armature piece 3 is acted upon by the spring force of the return spring 1, and the lower end of the armature core shaft 2 is tightly pressed against the upper conical surface of the plunger sleeve 4. At this time, the high-pressure fuel from the high-pressure common rail pipe fills the entire plunger control chamber, and has an upward hydraulic force on the lower conical surface of the armature core shaft 2. At this time, the armature receives the force in the downward direction, and the injector is in a closed state; when the injector receives the driving electrical signal, the solenoid valve 6 receives the electrical signal to generate electromagnetic suction, and the armature piece 3 is lifted up under the action of the electromagnetic suction force to overcome the spring force of the return spring 1. At this time, the high-pressure fuel in the control chamber returns to the fuel tank through the return oil port, so that the fuel pressure in the control chamber is reduced, and the injector starts to spray fuel through the nozzle 12; when the electromagnet 6 is powered off, the armature piece 3 and the armature core shaft 2 fall into place under the spring force of the return spring 1, the oil drain port is closed, and the oil pressure is re-established in the control chamber, so that the injector returns to the initial state, and the nozzle 12 is closed to stop spraying fuel.

Claims

1. A high-pressure common rail in-cylinder direct injection methanol injector, the structure of which includes: The electromagnetic valve assembly, the oil circuit control assembly, the nozzle assembly and the housing are characterized in that the electromagnetic valve assembly is located at the upper end of the methanol fuel injector, and converts the electrical signal into electromagnetic force through the instruction of the engine control unit; the oil circuit control assembly is connected to the lower end of the electromagnetic valve assembly, and controls the up and down movement of the needle valve through the plunger structure to achieve the opening and closing of the methanol fuel injector; the nozzle assembly is located at the bottom of the fuel injector, and is used to extend the methanol fuel injector into the engine cylinder and evenly spray the fuel into the combustion chamber through the spray hole; the various components are connected through the housing; The oil circuit control assembly includes a nut, a plunger sleeve, a control plunger and a plunger spring, wherein the nut is fixed to the housing through a threaded connection on the outside, and a flow channel is provided inside the plunger sleeve; the plunger sleeve is connected to the upper end of the control plunger, and a plunger control cavity is left in the middle; The solenoid valve assembly includes an electromagnet, an armature, a return spring, and an armature spring, wherein the armature is composed of an armature plate and an armature core shaft, and adopts a split structure design, and the lower end of the armature core shaft adopts a multi-curved surface configuration design, which is closely fitted with the upper end inclined surface of the plunger sleeve; the armature spring is assembled with the lower end of the armature, and the return spring resets the control plunger when the injector is closed; The fuel nozzle comprises a needle valve, a fuel nozzle and a fuel nozzle housing, wherein the needle valve is connected with a control plunger to control the opening and closing of the fuel injector; a fuel injection hole is arranged at the lower end of the fuel nozzle, through which the fuel is evenly injected into the combustion chamber to complete the even mixing of the air in the cylinder; and the fuel nozzle housing connects the fuel nozzle and the fuel injector housing.

2. A high-pressure common rail direct-injection methanol injector according to claim 1, characterized in that: The second conical surface at the lower end of the armature core shaft is coupled with the inclined surface at the upper end of the plunger sleeve, and the length of the coupling surface is L, and the value range of L is 7mm≤L≤8mm.

3. A high-pressure common rail direct-injection methanol injector according to claim 2, characterized in that: The contact surface length of the coupling surface at the lower end of the armature core shaft is a, the length of the coupling surface at the upper end of the plunger sleeve is b, and the value range of b / a is 1.5≤b / a≤1.

7.

4. A high-pressure common rail direct-injection methanol injector according to claim 3, characterized in that: The lower end of the armature core shaft adopts a multi-curved surface configuration design, the angle of the first cone surface is α, and its value range is 45.6°≤α≤50.5°, and the angle between the second cone surface and the center line of the armature core shaft is 29.3°≤β≤31.5°.

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