An oil-lubricated methanol fuel common rail injector

Abstract

This patent relates to the technical field of common rail injectors, specifically an oil-lubricated methanol fuel common rail injector, including an injector body, an oil sealing shell, a tight cap, an electro-hydraulic control component and a nozzle component. The upper part of the injector body is provided with an electric wire channel, a fuel inlet channel, a fuel return channel and an oil return channel, and the lower part of the injector body is provided with a cooling oil inlet channel and a cooling oil outlet channel. A cooling ring cavity is formed between the oil sealing shell and the injector body. The oil sealing shell is opened with an oil inlet channel. The injector body, the electro-hydraulic control component and the nozzle group component are provided with a connected lubricating oil inlet channel and a lubricating oil outlet channel. A nozzle cooling cavity is provided at the bottom of the nozzle assembly, a control valve lubricating oil channel is provided in the injector body, and a needle valve lubricating oil channel is provided in the nozzle assembly. The oil circulation cooling oil circuit composed of the oil inlet channel, the cooling ring cavity, the cooling oil inlet channel, the cooling oil outlet channel, the nozzle cooling cavity and the oil return channel reduces the injector temperature and prevents the methanol fuel temperature from exceeding the boiling point. It can be applied to methanol fuel.

Description

Technical Field

[0001] The invention relates to the technical field of common rail fuel injectors, in particular to an oil-lubricated methanol fuel common rail fuel injector. Background Art

[0002] The electronically controlled common rail fuel system is an injection system based on mechanical, hydraulic and electrical technologies. This system uses a common rail pipe with a certain volume between the fuel supply pump and the injector to accumulate fuel to smooth pressure fluctuations, and then transports it to each injector through the oil pipe. The action of the injector solenoid valve controls the opening and closing of the injector. This system has the advantages of stable injection pressure and flexible adjustment of injection pressure and injection process.

[0003] Due to the needs of environmental protection and energy strategy, engines that use new energy sources such as methanol as fuel have unique advantages in industry prospects and have received widespread attention. However, although methanol as a fuel has the advantages of high industrial output and low emission pollution, it still has many application difficulties compared to traditional fuel oil. First, methanol lacks lubricity, so the lubrication of methanol fuel injectors is a design difficulty; second, methanol has a low boiling point, but the heat generated by combustion in the cylinder is high, and the working environment temperature is high, so there are high requirements for preventing methanol fuel from overheating and vaporization; third, methanol is toxic and volatile, so the sealing of related systems must be guaranteed. Due to the particularity of methanol fuel, the existing common rail fuel system can only be applied to fuel oil fuel, not methanol fuel. Summary of the invention

[0004] The present invention is intended to provide an oil-lubricated methanol fuel common rail injector to solve the problem that the existing common rail fuel system can only be applied to fuel oil but not to methanol fuel.

[0005] In order to achieve the above-mentioned object, the basic scheme of the present invention is as follows: an oil-lubricated methanol fuel common rail injector, comprising an injector body, an oil sealing shell, a tight cap, an electro-hydraulic control assembly and a nozzle assembly, wherein the oil sealing shell is connected to the outside of the injector body, the electro-hydraulic control assembly is installed in the injector body, the nozzle assembly is connected to the electro-hydraulic control assembly, and the nozzle assembly is fixed to the injector body through the tight cap;

[0006] An electric wire channel, a fuel inlet channel, a fuel return channel and an oil return channel are provided at the upper part of the injector body, the fuel inlet channel is communicated with the nozzle assembly, the fuel return channel is communicated with the electro-hydraulic control assembly, a cooling inlet channel and a cooling outlet channel are provided at the lower part of the injector body, a cooling ring cavity is formed between the oil sealing shell and the injector body, an oil inlet channel is opened on the oil sealing shell, the oil inlet channel, the cooling inlet channel, the cooling outlet channel and the oil return channel are all communicated with the cooling ring cavity, a connected lubrication inlet channel and a lubrication outlet channel are provided in the injector body, the electro-hydraulic control assembly and the nozzle group assembly, a nozzle cooling cavity is provided at the bottom of the nozzle assembly, the lubrication inlet channel and the lubrication outlet channel are both communicated with the nozzle cooling cavity, a control valve lubrication channel is provided in the injector body, a needle valve lubrication channel is provided in the nozzle assembly, and the control valve lubrication channel and the needle valve lubrication channel are both connected to the lubrication inlet channel.

[0007] Further, the electro-hydraulic control mechanism includes a compression spring, an electromagnet, a control reset spring, an armature, an air gap adjustment sleeve, a control guide sleeve, a control valve core, a lift adjustment gasket, a ball valve seat, a steel ball and an orifice plate. The compression spring, the electromagnet, the air gap adjustment sleeve, the control guide sleeve and the lift adjustment gasket are assembled in the injector body from top to bottom. The control valve core and the control guide sleeve are matched as a pair. The control reset spring is installed in the middle of the electromagnet. The armature is slidably connected to the middle of the electromagnet, and the lower end of the control reset spring is fixedly connected to the armature. The armature is fixed to the control valve core. The control valve core, ball valve seat and steel ball are in contact in sequence, the compression spring presses the electromagnet, air gap adjustment sleeve, control guide sleeve and lift adjustment gasket onto the orifice plate, an inlet flow hole and a return flow hole are arranged inside the orifice plate, the inlet flow hole and the return flow hole are both connected with the injection group assembly, the inlet flow hole is connected with the fuel inlet channel, the fuel return channel is connected with the upper end of the return flow hole, the steel ball is located above the return flow hole, and the steel ball can block the return flow hole, the lower end of the orifice plate is in contact with the nozzle assembly, and the control valve lubrication oil channel is connected between the control guide sleeve and the injector body.

[0008] Furthermore, the nozzle assembly includes a piston guide sleeve, a hydraulic piston, a needle valve return spring, a pressure regulating gasket, a needle valve, a needle valve body and a cooling sleeve. The piston guide sleeve, the hydraulic piston, the needle valve return spring, the pressure regulating gasket and the needle valve are sequentially installed in the needle valve body from top to bottom. The upper end surface of the piston guide sleeve, the needle valve body and the orifice plate form a pressure control chamber. The inlet flow hole and the return flow hole are both connected to the pressure control chamber. The upper end of the hydraulic piston is slidably connected in the piston guide sleeve. The needle valve return spring is sleeved on the hydraulic piston. The upper end of the needle valve return spring abuts against the bottom surface of the piston guide sleeve, the lower end of the needle valve return spring abuts against the pressure regulating gasket, the needle valve is slidably connected in the needle valve body, a fuel cavity is provided between the lower part of the needle valve and the needle valve body, the fuel inlet channel is communicated with the fuel cavity, an oil injection hole is provided at the bottom of the needle valve body, the needle valve can close the oil injection hole, the cooling sleeve is fixed on the circumference of the bottom of the needle valve body, a nozzle cooling cavity is formed between the cooling sleeve and the needle valve body, and the needle valve lubricating oil channel is communicated between the piston guide sleeve and the needle valve body.

[0009] Furthermore, a guide sleeve lubrication ring groove is provided on the outer side of the middle part of the control guide sleeve, and the guide sleeve lubrication ring groove is connected with the lubrication oil channel of the control valve. Sealing grooves are provided at both ends of the control guide sleeve. A plurality of valve core lubrication ring grooves are provided in the middle part of the control valve core, and the plurality of valve core lubrication ring grooves are connected through a vertical strip groove. A through hole is provided on the control guide sleeve, and the through hole connects the guide sleeve lubrication ring groove and any valve core lubrication ring groove.

[0010] Furthermore, both ends of the orifice plate are provided with oil ring grooves, the oil ring grooves are connected with the oil inlet passage and the oil return passage, and the oil ring grooves are located outside the fuel inlet passage and the fuel return passage.

[0011] Furthermore, a sealing ring groove is provided on the upper part of the hydraulic piston, a plurality of oblique grooves are circumferentially provided in the middle and lower part of the hydraulic piston to the outside of the mating surface, the needle valve is provided with a sealing ring groove at the lower end of the part mating with the needle valve body, and a plurality of oblique grooves are circumferentially provided in the middle and upper part of the part mating with the needle valve body to the outside of the mating surface.

[0012] The beneficial effects of this solution are as follows: (1) By designing the lubricating oil circuit inside the injector body, which is composed of the engine oil inlet channel, the control valve lubricating oil channel, the needle valve lubricating oil channel, and the lubricating ring groove on the moving parts, the moving parts are lubricated by utilizing the better lubricity of the introduced engine oil, thereby effectively improving the service life of the injector parts; by designing the sealing ring groove, the gap sealing principle is utilized to prevent methanol from mixing with the engine oil, thereby maintaining the lubricating ability of the engine oil.

[0013] (2) By designing an oil circulation cooling oil circuit consisting of an oil inlet channel, a cooling ring cavity, a cooling oil inlet channel, a cooling inlet and outlet oil channel, a nozzle cooling cavity, and an oil return channel, the temperature of the injector is reduced at the important working position and the outer wall of the electronic control injector to prevent the temperature of the methanol fuel from exceeding the boiling point.

[0014] (3) The oil ring grooves at both ends of the orifice plate are connected to the oil inlet and oil return channels, so that the oil can fill the gaps between parts; by utilizing the oil pressure and the immiscible characteristics of oil and methanol, the oil seal can further prevent the leakage and volatilization of methanol in the injector.

[0015] (4) By directly controlling the operation of the fuel injector through electromagnetic components, the opening and closing time of a single fuel injector on the engine can be changed at any time, making the control more flexible. The operation of the fuel injector is controlled by the fuel's own hydraulic pressure. The start-up pressure is not bound to the spring structure and can be adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0017] Figure 2 A specific schematic diagram of a fuel channel in an embodiment of the present invention;

[0018] Figure 3 A specific schematic diagram of an oil passage in an embodiment of the present invention;

[0019] Figure 4 Schematic diagram of the specific structure of the orifice plate in the embodiment of the present invention. DETAILED DESCRIPTION

[0020] 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.

[0021] The reference numerals in the drawings of the specification include: injector body 1, connecting screw 2, oil sealing housing 3, compression spring 4, electromagnet 5, control reset spring 6, armature screw 7, armature 8, air gap adjustment sleeve 9, control guide sleeve 10, control valve core 11, lift adjustment gasket 12, ball valve seat 13, steel ball 14, orifice plate 15, tight cap 16, piston guide sleeve 17, hydraulic piston 18, needle valve reset spring 19, pressure regulating gasket 20, needle valve 21, needle valve Body 22, wire channel 101, fuel inlet channel 102, fuel return channel 103, reflux flow hole 104, inlet flow hole 105, pressure control chamber 106, fuel cavity 107, oil inlet channel 108, cooling ring cavity 109, cooling oil inlet channel 110, control valve lubricating oil channel 111, oil ring groove 112, needle valve lubricating oil channel 113, sealing ring groove 114, oil return channel 115, cooling oil outlet channel 116, nozzle cooling cavity 117.

[0022] Example

[0023] Basically as attached Figure 1 As shown: an oil-lubricated methanol fuel common rail injector, comprising an injector body 1, an oil sealing shell 3, a tight cap 16, an electro-hydraulic control assembly and a nozzle assembly, the oil sealing shell 3 is connected to the outside of the injector body 1 by a connecting screw 2, the electro-hydraulic control assembly is installed in the injector body 1, the nozzle assembly is connected to the electro-hydraulic control assembly, and the nozzle assembly is fixed to the injector body 1 by a tight cap 16;

[0024] Combination Figure 2 , Figure 3 As shown, the upper part of the injector body 1 is provided with a wire channel 101, a fuel inlet channel 102, a fuel return channel 103 and an oil return channel 115, the fuel inlet channel is connected to the nozzle assembly, the fuel return channel 103 is connected to the electro-hydraulic control assembly, the lower part of the injector body 1 is provided with a cooling oil inlet channel 110 and a cooling oil outlet channel 116, a cooling ring cavity 109 is formed between the oil sealing shell 3 and the injector body 1, and an oil inlet channel 108 is opened on the oil sealing shell 3, the oil inlet channel 108, the cooling oil inlet channel 110, the cooling oil outlet channel 116 are provided. The oil return passage 116 and the oil return passage 115 are both connected to the cooling ring cavity 109. The injector body 1, the electro-hydraulic control component and the nozzle group component are provided with connected lubricating oil inlet passages and lubricating oil outlet passages. A nozzle cooling cavity 117 is provided at the bottom of the nozzle assembly. The lubricating oil inlet passage and the lubricating oil outlet passage are both connected to the nozzle cooling cavity 117. A control valve lubricating oil passage 111 is provided in the injector body 1, and a needle valve lubricating oil passage 113 is provided in the nozzle assembly. The control valve lubricating oil passage 111 and the needle valve lubricating oil passage 113 are both connected to the lubricating oil inlet passage.

[0025] The electro-hydraulic control mechanism includes a compression spring 4, an electromagnet 5, a control reset spring 6, an armature screw 7, an armature 8, an air gap adjustment sleeve 9, a control guide sleeve 10, a control valve core 11, a lift adjustment gasket 12, a ball valve seat 13, a steel ball 14 and an orifice plate 15. The compression spring 4, the electromagnet 5, the air gap adjustment sleeve 9, the control guide sleeve 10 and the lift adjustment gasket 12 are assembled in the injector body 1 from top to bottom. The control valve core 11 and the control guide sleeve 10 are matched as a pair. The control reset spring 6 is installed in the middle of the electromagnet 5, the armature 8 is slidably connected to the middle of the electromagnet 5, and the lower end of the control reset spring 6 is fixedly connected to the armature 8. The armature 8 and the control valve The top of the core 11 is fixed with an armature screw 7, the control valve core 11, the ball valve seat 13 and the steel ball 14 are in contact in sequence, the compression spring 4 presses the electromagnet 5, the air gap adjustment sleeve 9, the control guide sleeve 10 and the lift adjustment gasket 12 onto the orifice plate 15, and the orifice plate 15 is provided with an inlet flow hole 105 and a return flow hole 104 inside, the inlet flow hole 105 and the return flow hole 104 are both connected to the injection group assembly, the inlet flow hole 105 is connected to the fuel inlet channel, the fuel return channel is connected to the upper end of the return flow hole 104, the steel ball 14 is located above the return flow hole 104, and the steel ball 14 can block the return flow hole 104, the lower end of the orifice plate 15 is in contact with the nozzle assembly, combined with Figure 4 As shown, both ends of the orifice plate 15 are provided with oil ring grooves 112, and the oil ring grooves 112 are connected with the oil inlet channel 108 and the oil return channel 115, and the oil ring grooves 112 are not connected with the fuel inlet channel 102 and the fuel return channel; the control valve lubricating oil channel 111 is connected between the control guide sleeve 10 and the injector body 1, and a guide sleeve lubricating ring groove is provided on the outer side of the middle part of the control guide sleeve 10, and the guide sleeve lubricating ring groove is connected with the control valve lubricating oil channel 111, and sealing grooves are provided at both ends of the control guide sleeve 10, and a plurality of valve core lubricating ring grooves are provided in the middle part of the control valve core 11, and the plurality of valve core lubricating ring grooves are connected through a vertical strip groove, and a through hole is provided on the control guide sleeve 10, and the through hole connects the guide sleeve lubricating ring groove and any valve core lubricating ring groove.

[0026] The nozzle assembly includes a piston guide sleeve 17, a hydraulic piston 18, a needle valve return spring 19, a pressure regulating gasket 20, a needle valve 21, a needle valve body 22 and a cooling sleeve. The piston guide sleeve 17, the hydraulic piston 18, the needle valve return spring 19, the pressure regulating gasket 20 and the needle valve 21 are sequentially installed in the needle valve body 22 from top to bottom. The upper end surface of the piston guide sleeve 17, the needle valve body 22 and the orifice plate 15 enclose a pressure control chamber 106. The inlet flow hole 105 and the return flow hole 104 are both connected to the pressure control chamber 106. The upper end of the hydraulic piston 18 is slidably connected in the piston guide sleeve 17. The needle valve return spring 19 is sleeved on the hydraulic piston 18, and the upper end of the needle valve return spring 19 is against the bottom surface of the piston guide sleeve 17, and the lower end of the needle valve return spring 19 is against the pressure regulating gasket 20. The needle valve 21 is slidably connected in the needle valve body 22, and a fuel chamber 107 is provided between the lower part of the needle valve 21 and the needle valve body 22, and the fuel inlet passage is connected to the fuel chamber 107. An oil injection hole is provided at the bottom of the needle valve body 22, and the needle valve 21 can close the oil injection hole. The cooling sleeve is fixed on the circumference of the bottom of the needle valve body 22, and a nozzle cooling chamber 117 is formed between the cooling sleeve and the needle valve body 22. The needle valve lubricating oil passage 113 is connected between the piston guide sleeve 17 and the needle valve body 22; a sealing ring groove 114 is provided on the upper part of the hydraulic piston 18, and a plurality of inclined grooves are provided on the circumference of the middle and lower part of the hydraulic piston 18 to the outside of the matching surface, and the needle valve 21 is provided with a sealing ring groove 114 at the lower end of the matching part with the needle valve body 22, and a plurality of inclined grooves are provided on the circumference of the middle and upper part of the matching part with the needle valve body 22 to the outside of the matching surface.

[0027] The specific implementation process is as follows: when the electromagnet 5 is not energized, the methanol fuel flows into the fuel cavity 107 through the fuel inlet channel 102, and at the same time flows into the pressure control chamber 106 through the inlet flow hole 105. At this time, the control valve core 11 presses the ball valve seat 13, so that the steel ball 14 abuts against the return flow hole 104. The fuel pressure in the pressure control chamber 106 is equal to the fuel pressure in the fuel cavity 107. The hydraulic piston 18 and the two ends of the needle valve 21 are subjected to the fuel pressure and the spring force transmitted by the needle valve return spring 19. The combined force direction of the needle valve 21 is downward, maintaining the seated state, and the cone surface at the lower end of the needle valve 21 can abut against the injection end of the needle valve body 22.

[0028] When the electromagnet 5 is energized, it generates electromagnetic force, and the armature 8 is attracted. When the electromagnetic force is greater than the spring force of the control return spring 6, the control valve core 11 moves upward with the armature 8 to the large diameter of its bottom end and contacts the bottom end of the control guide sleeve 10 under the influence of the combined force. The steel ball 14 is out of position, and the reflux hole 104 is opened at this time. The oil in the pressure control chamber 106 flows up through the reflux hole 104, passes through the ball valve seat 13, and finally flows out of the fuel injector from the fuel return channel 103. At this time, the liquid pressure in the pressure control chamber 106 decreases, and the liquid pressure difference between the hydraulic piston 18 and the needle valve 21 increases. The needle valve 21 moves upward and opens the seal between it and the needle valve body 22, and the fuel is sprayed from the spray hole, and the injection process begins.

[0029] When the electromagnet 5 is powered off, the control reset spring 6 makes the control valve core 11 fall again, the steel ball 14 presses against the return flow hole 104 again, and the inlet flow hole 105 replenishes oil to the pressure control chamber 106. The hydraulic pressure increases. The needle valve 21 moves downward under the combined action of the hydraulic pressure transmitted by the hydraulic piston 18 and the needle valve reset spring 19, and the cone surface at the lower end of the needle valve 21 presses against the injection port of the needle valve body 22 again, and the injection process ends.

[0030] Since the injector uses the fuel liquid pressure difference to control the operation of the injector, when no power is supplied, even if the fuel liquid pressure increases, the upper liquid pressure on the needle valve 21 is still greater than the lower liquid pressure, and it will only change when power is supplied. Therefore, its start-up pressure is not bound to the spring structure, and the start-up pressure can be freely adjusted within a certain range. By directly controlling the operation of the injector through the electromagnetic element, the opening and closing time of a single injector on the engine can be changed at any time, making the control more flexible.

[0031] The lubricating oil circuit of the moving parts of the injector is composed of the cooling oil inlet channel 110, the control valve lubricating oil channel 111, and the needle valve lubricating oil channel 113. The engine oil flows into the surface of the control valve core 11 through the control valve lubricating oil channel 111 and the through hole on the control guide sleeve 10. Several lubricating ring grooves are opened on the guide section, and each groove is connected with the through hole on the control guide sleeve 10 through a vertical strip groove. The engine oil fully lubricates the surface of the control valve core 11 through these sections of lubricating ring grooves; the engine oil flows into the middle cavity of the needle valve body 22 through the needle valve lubricating oil channel 113, and flows into the surfaces of the hydraulic piston 18 and the needle valve 21 through the inclined grooves on both. The engine oil fully lubricates the surface of the parts through these sections of inclined grooves; because the engine oil has better lubricity than methanol, the moving parts are lubricated through the internal engine oil circuit, which can effectively improve the service life of the injector parts.

[0032] The two sealing grooves opened at the bottom end of the guide section of the control valve core 11, the two sealing ring grooves 114 opened on the upper end of the surface of the hydraulic piston 18 and the sealing ring groove 114 opened on the lower end of the surface of the needle valve 21 play the role of dynamic sealing. When methanol leaks into the first ring that is closer, the pressure will drop sharply with the sudden increase of the flow area, resulting in a significant reduction in the leakage rate of methanol due to the low pressure when it leaks into the second ring. This can prevent methanol from mixing with the engine oil and maintain the lubricating ability of the engine oil.

[0033] The circulating cooling oil circuit of the injector is composed of the oil inlet channel 108, the cooling ring cavity 109, the cooling oil inlet channel 110, the nozzle cooling cavity 117, the cooling oil outlet channel 116 and the oil return channel 115. The circulating cooling oil circuit is divided into three paths. One path is formed through the cooling ring cavity 109 and the oil ring grooves 112 opened at both ends of the orifice plate 15 to form a body cooling annular oil circuit, which mainly plays a heat insulation role, separates the cylinder from the fuel, and uses the cooling ring cavity 109 to prevent the high temperature on the cylinder from transferring heat to the methanol; the second path enters the oil cavity surrounded by the electromagnet 5, the control guide sleeve 10 and the sealing ring through the cooling oil inlet channel 110, and is connected to the cooling oil outlet channel 116 through the slots on the air gap adjustment sleeve 9. The cooling oil circuit mainly cools the electromagnetic components that generate heat and are more sensitive; the third path cools the nozzle through the nozzle cooling cavity 117 at the bottom of the needle valve 21. The three-path circulating oil circuit reduces the overall temperature of the injector to prevent the temperature of the methanol fuel from exceeding the boiling point.

[0034] Considering that the two ends of the orifice plate 15 are flat and tightly sealed, the sealing area is large and leakage is most likely to occur. Therefore, an oil ring groove 112 is opened at both ends of the orifice plate 15. The oil ring groove 112 is outside the fuel inlet channel 102 and the fuel return channel 103, and is connected to the oil inlet channel 108 and the oil return channel 115. During operation, the ring groove is filled with oil to form a hydraulic ring belt, and its pressure can prevent the leaked low-pressure fuel from flowing to the outside of the hydraulic ring belt. At the same time, due to the immiscible characteristics of oil and methanol, the oil seal is used to further prevent methanol from leaking and volatilizing.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0036] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An oil-lubricated methanol fuel common rail injector, characterized in that: It includes a fuel injector body, an oil sealing shell, a tight cap, an electro-hydraulic control assembly and a nozzle assembly, wherein the oil sealing shell is connected to the outside of the fuel injector body, the electro-hydraulic control assembly is installed in the fuel injector body, the nozzle assembly is connected to the electro-hydraulic control assembly, and the nozzle assembly is fixed to the fuel injector body through the tight cap; The upper part of the injector body is provided with an electric wire channel, a fuel inlet channel, a fuel return channel and an oil return channel, the fuel inlet channel is communicated with the nozzle assembly, the fuel return channel is communicated with the electro-hydraulic control assembly, the lower part of the injector body is provided with a cooling oil inlet channel and a cooling oil outlet channel, a cooling ring cavity is formed between the oil sealing shell and the injector body, the oil sealing shell is provided with an oil inlet channel, the oil inlet channel, the cooling oil inlet channel, the cooling oil outlet channel and the oil return channel are all communicated with the cooling ring cavity, the injector body, the electro-hydraulic control assembly and the nozzle group assembly are provided with a communicating lubricating oil inlet channel and a lubricating oil outlet channel, the bottom of the nozzle assembly is provided with a nozzle cooling cavity, the lubricating oil inlet channel and the lubricating oil outlet channel are both communicated with the nozzle cooling cavity, the injector body is provided with a control valve lubricating oil channel, the nozzle assembly is provided with a needle valve lubricating oil channel, the control valve lubricating oil channel and the needle valve lubricating oil channel are both connected to the lubricating oil inlet channel, The electro-hydraulic control assembly includes a compression spring, an electromagnet, a control reset spring, an armature, an air gap adjustment sleeve, a control guide sleeve, a control valve core, a lift adjustment gasket, a ball valve seat, a steel ball and an orifice plate. The compression spring, the electromagnet, the air gap adjustment sleeve, the control guide sleeve and the lift adjustment gasket are assembled in the injector body from top to bottom. The control valve core and the control guide sleeve are matched as a pair. The control reset spring is installed in the middle of the electromagnet. The armature is slidably connected to the middle of the electromagnet, and the lower end of the control reset spring is fixedly connected to the armature. The armature is fixed to the control valve core. The control valve core, the ball valve seat and the steel ball are in contact in sequence, and the clamping spring presses the electromagnet, the air gap adjustment sleeve, the control guide sleeve and the lift adjustment gasket onto the orifice plate. An inlet flow hole and a return flow hole are arranged inside the orifice plate, and the inlet flow hole and the return flow hole are both connected to the injection group assembly. The inlet flow hole is connected to the fuel inlet flow channel, and the fuel return flow channel is connected to the upper end of the return flow hole. The steel ball is located above the return flow hole, and the steel ball can block the return flow hole. The lower end of the orifice plate is in contact with the nozzle assembly, and the control valve lubricating oil channel is connected between the control guide sleeve and the injector body.

2. The oil-lubricated methanol fuel common rail injector according to claim 1, characterized in that: The nozzle assembly includes a piston guide sleeve, a hydraulic piston, a needle valve return spring, a pressure regulating gasket, a needle valve, a needle valve body and a cooling sleeve. The piston guide sleeve, the hydraulic piston, the needle valve return spring, the pressure regulating gasket and the needle valve are sequentially installed in the needle valve body from top to bottom. The upper end surface of the piston guide sleeve, the needle valve body and the orifice plate form a pressure control chamber. The inlet flow hole and the return flow hole are both connected to the pressure control chamber. The upper end of the hydraulic piston is slidably connected in the piston guide sleeve. The needle valve return spring is sleeved on the hydraulic piston. The upper end of the needle valve return spring abuts against the bottom surface of the piston guide sleeve, and the lower end of the needle valve return spring abuts against the pressure regulating gasket. The needle valve is slidably connected in the needle valve body. A fuel cavity is provided between the lower part of the needle valve and the needle valve body. The fuel inlet channel is connected to the fuel cavity. An oil injection hole is provided at the bottom of the needle valve body. The needle valve can close the oil injection hole. The cooling sleeve is fixed on the circumference of the bottom of the needle valve body. A nozzle cooling cavity is formed between the cooling sleeve and the needle valve body. The needle valve lubricating oil channel is connected between the piston guide sleeve and the needle valve body.

3. The oil-lubricated methanol fuel common rail injector according to claim 2, characterized in that: A guide sleeve lubrication ring groove is provided on the outer side of the middle part of the control guide sleeve, and the guide sleeve lubrication ring groove is connected with the lubrication oil channel of the control valve. Sealing grooves are provided at both ends of the control guide sleeve. A plurality of valve core lubrication ring grooves are provided in the middle part of the control valve core, and the plurality of valve core lubrication ring grooves are connected through a vertical strip groove. A through hole is provided on the control guide sleeve, and the through hole connects the guide sleeve lubrication ring groove and any valve core lubrication ring groove.

4. The oil-lubricated methanol fuel common rail injector according to claim 3, characterized in that: Both ends of the orifice plate are provided with oil ring grooves, the oil ring grooves are connected with the oil inlet passage and the oil return passage, and the oil ring grooves are located outside the fuel inlet passage and the fuel return passage.

5. The oil-lubricated methanol fuel common rail injector according to claim 4, characterized in that: The hydraulic piston is provided with a sealing ring groove on the upper part, and a plurality of oblique grooves are circumferentially provided in the middle and lower part of the hydraulic piston to the outside of the mating surface. The needle valve is provided with a sealing ring groove at the lower end of the part that cooperates with the needle valve body, and a plurality of oblique grooves are circumferentially provided in the middle and upper part of the part that cooperates with the needle valve body to the outside of the mating surface.

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