CN219865274U - Self-lubricating efficient mixed cold-type hydrogen injector and direct-injection hydrogen internal combustion engine - Google Patents

Abstract

The utility model belongs to the field of hydrogen internal combustion engines, and particularly discloses a self-lubricating high-efficiency mixed cold type hydrogen injector and a direct injection hydrogen internal combustion engine, which comprise a valve body, a needle valve, a nozzle and an oil way, wherein: the needle valve is arranged in the valve body and can axially reciprocate up and down; the lower side of the valve body is provided with a hydrogen cavity, and the nozzle is arranged at the lower end of the hydrogen cavity; the oil way comprises an oil pipe assembly, a large reticulate pattern and a small reticulate pattern, and the oil pipe assembly is arranged in the valve body and is communicated with the large reticulate pattern; the needle valve and the middle part of the valve body are provided with a matching surface, the large reticulate pattern is arranged at the matching surface of the valve body, and the small reticulate pattern is arranged at the matching surface of the needle valve. The utility model provides a cold type direct injection hydrogen injector which is provided with an oil storage grid lubricating structure and a focusing swirl nozzle and can be used for hydrogen internal combustion engines such as vehicles and ships, and the cold type direct injection hydrogen injector can realize the omnibearing lubrication and sealing of a hydrogen injector valve and a valve body and reduce abrasion.

Description

Self-lubricating efficient mixed cold-type hydrogen injector and direct-injection hydrogen internal combustion engine

Technical Field

The utility model belongs to the field of hydrogen internal combustion engines, and particularly relates to a self-lubricating high-efficiency mixed cold type hydrogen injector and a direct injection hydrogen internal combustion engine.

Background

In recent years, internal combustion engines for vehicles and ships have come to be used as various alternative energy sources. The utilization of hydrogen energy is an important part of alternative energy sources. The hydrogen internal combustion engine has the advantages of near zero carbon emission, high thermal efficiency, low cost, capability of adopting the traditional internal combustion engine production technology and the like; the in-cylinder high-pressure direct injection has the advantages of avoiding tempering, improving power rise, improving thermal efficiency and the like. Therefore, the high-pressure direct-injection hydrogen internal combustion engine is an object of interest for research institutions and enterprises, and the hydrogen injector suitable for the high-pressure direct-injection hydrogen internal combustion engine is also a key technology of the hydrogen internal combustion engine.

Then, the high-pressure direct injection hydrogen can bring some important problems, specifically, the hydrogen can not lubricate parts, the damping effect is weak, meanwhile, the hydrogen injector operates at an ultra-high speed, and higher requirements are put on the anti-abrasion design, for example, the prior hydrogen injector needs to manually inject lubricating oil into the inner matching surface before each use, and the service life of the prior hydrogen injector is still only 48 hours; in addition, the hydrogen has small molecular weight, wide flammability limit and low ignition energy, and has higher requirements on sealing design and cooling design, and the hydrogen injector needs to be prevented from becoming a hot spot of a combustion chamber so as not to generate preignition.

The above-described easy ignition feature of hydrogen also brings about knocking problems. Based on the stratified lean combustion technique, knocking can be reduced and thermal efficiency can be improved. However, because hydrogen is easy to diffuse, the spray hole of the hydrogen sprayer needs to be specially designed to realize focused swirl injection, so that on one hand, the hydrogen is gathered near a spark plug, the hydrogen is prevented from approaching a high-temperature wall surface, on the other hand, the hydrogen-air mixing in a hydrogen concentration area is realized through swirl, and the combustion speed is improved.

The corresponding patent application No. 202220450571.5 provides a hydrogen internal combustion engine injector that utilizes the concept of multiple split hydrogen beams forming a total hydrogen beam swirl to promote hydrogen-air mixing. However, the swirl flow is generated in the premixing cavity, the axial speed is too small, the flow resistance at the nozzle is large, the swirl flow intensity is easy to attenuate, the preignition and the hydrogen injection flow at the nozzle are insufficient, and the requirement of inhibiting knocking by stratified combustion cannot be met; on the other hand, the needle valve and the end matching surface of the valve body adopt a gasket structure, the gasket is not effectively fixed, the gasket is easy to leave the working position to cause failure, and meanwhile, the abrasion strength cannot be reduced, and only the abrasion is transferred to the gasket.

The corresponding patent application No. 202220448673.3 provides a hydrogen injector for a hydrogen internal combustion engine that utilizes an air stream to cool a nozzle to inhibit pre-ignition. However, flammable gas is formed at the nozzle, the refrigerating effect of air is poor, and the abnormal combustion occurrence rate such as pre-combustion and the like can not be reduced or possibly even improved comprehensively; at the same time, the structure is not suitable for stratified combustion systems, nor can it alleviate wear.

Corresponding patent application number 201510077494.8 provides a natural gas-diesel dual fuel injector with self-lubricating function. However, the structure of the fuel tank is easy to cause the problems of air channel blockage, pre-ignition, unstable oiling control and the like; moreover, the diesel oil is used as the ignition agent, so that the loss is faster, the hydrogen internal combustion engine can be free of the ignition agent, and a lubrication scheme with lower oil consumption exists; in addition, the structure cannot play the effect of suppressing knocking by stratified combustion if the structure is changed to hydrogen injection.

The corresponding patent application No. 201711002268.9 provides an injector for gaseous fuel vehicles with improved lubrication characteristics that exploits the concept of a groove structure to store a lubricating oil for lubrication of the mating surfaces. However, firstly, the lubricating oil in the structure is easy to consume and cannot be conveniently and conveniently replenished after being consumed; secondly, the passage for discharging the lubricating oil containing abrasive grains in the structure shares the same space with the fuel gas, and the problem of the loss of the fuel gas from the path is not solved; moreover, the lubricating oil connecting groove structure is obliquely arranged towards the same rotation direction, so that the needle valve is easy to rotate and slightly wear; again, the nozzle structure is not designed for the need to suppress pre-ignition and promote high-mixing stratified combustion.

The corresponding patent of application number US11739867 provides a continuous self-lubricating oil injector, which relates to the idea of using an oil storage grid to enhance lubrication. However, the device relies on continuous oil supply of an oil sprayer, if piezoelectric hydrogen spraying is changed, oil in an oil storage grid is rapidly consumed, continuous self-lubrication and liquid sealing cannot be realized, and meanwhile, extra abrasion caused by the fact that abrasive particles are transported to a nozzle is not fully considered; also, this structure cannot meet the requirements of efficient mixed stratified combustion, nor can it prevent pre-ignition at the nozzle.

Disclosure of Invention

Aiming at the defects or improvement demands of the prior art, the utility model provides a self-lubricating high-efficiency mixed cold type hydrogen injector and a direct injection hydrogen internal combustion engine, and aims to realize the omnibearing lubrication and sealing of a hydrogen injector valve and a valve body and reduce abrasion.

In order to achieve the above object, according to an aspect of the present utility model, there is provided a self-lubricating high-efficiency hybrid cold type hydrogen injector comprising a valve body, a needle valve, a nozzle, and an oil passage, wherein:

the needle valve is arranged in the valve body and can axially reciprocate up and down; the lower side of the interior of the valve body is provided with a hydrogen cavity, and the nozzle is arranged at the lower end of the hydrogen cavity;

the oil way comprises an oil pipe assembly, a large reticulate pattern and a small reticulate pattern, and the oil pipe assembly is arranged in the valve body and is communicated with the large reticulate pattern; the needle valve and the middle part of the valve body are provided with matching surfaces, the large reticulate patterns are arranged at the matching surfaces of the valve body, and the small reticulate patterns are arranged at the matching surfaces of the needle valve.

As a further preferred aspect, the oil pipe assembly includes a plurality of circulation oil paths including an oil filler pipe, an oil bag and a connecting oil pipe, wherein the oil filler pipe is communicated with the oil bag; the upper side oil bag and the large reticulate pattern upper end are connected with the lower side oil bag and the large reticulate pattern lower end through the connecting oil pipe, so that a circulating oil path is formed.

Further preferably, the oil pressure of each circulation oil passage is balanced and stabilized by communicating the circumferentially adjacent circulation oil passages through the communication oil pipe, and the abrasive grains generated by long-term operation of the oil passages can be precipitated and accumulated, thereby further reducing abrasion.

As a further preference, the small reticulate pattern has a reticulate pattern density greater than the reticulate pattern density of the large reticulate pattern.

As a further preferable aspect, the oil filler pipe is provided with a one-way pressure valve for ensuring one-way oil filling and stabilizing oil pressure.

As a further preferable aspect, the tolerance of the mating surface of the needle valve and the valve body is made of a base shaft, and the mating clearance h of the mating surface satisfies: gamma/h > p, the roughness Ra of the mating surface satisfies: ra < h/(λ v 2); where γ is the surface tension coefficient of the lubricating oil in the oil passage, p is the free surface pressure peak value of the lubricating oil between the mating surfaces when the discharge amount is 0, and λ is the film thickness ratio.

Specifically, the self-lubricating principle is as follows: because the gap between the matching surfaces of the needle valve is small, oil leakage is avoided, when the needle valve is in an upward direction, under the action of reciprocating dragging of the needle valve, the lubricating oil in the oil way also moves upward, the upper oil sac is boosted, the lower oil sac is depressurized, and the lubricating oil forms a circulation along the direction of the matching surfaces, the upper oil sac, the lower oil sac and the matching surfaces; the needle valve is in the same way when descending, and forms reverse circulation, thereby realizing self circulation of lubricating oil, and enabling the circumferential matching surface of the needle valve coupling to be subjected to omnibearing durable lubrication and sealing.

As a further preferable mode, the hydrogen sprayer also comprises a cooling pipeline, and a phase change medium capable of realizing gas-liquid conversion is arranged in the cooling pipeline; and the heat absorption section of the cooling pipeline is paved around the nozzle, and the heat release section of the cooling pipeline is paved around the oil way.

As a further preferred, the medium in the cooling duct is sodium.

Specifically, the cooling principle is: when the hydrogen sprayer works, the nozzle of the hydrogen sprayer is heated, and the liquid working medium in the cooling pipeline absorbs heat and gasifies, so that the temperature of the nozzle of the hydrogen sprayer can be maintained not to be too high, and the pre-ignition of the nozzle is avoided; under the action of gravity and/or surface tension, the gasified working medium ascends to the heat release section, and after heat release liquefaction, the working medium is cooled and flows back to the heat absorption section to complete circulation, and the released heat is used for keeping the temperature of lubricating oil, improving the fluidity of the lubricating oil and improving the lubricating effect.

As a further preferred feature, the nozzle is integrally provided within the valve body, the nozzle comprising a pressure chamber and a plurality of injection orifices, the injection orifices communicating with the hydrogen chamber through the pressure chamber thereon; the spray hole is tubular, and the spray hole axis and the hydrogen injector axis have a cone angle and an eccentric distance to form a focusing swirl nozzle.

As a further preferred option, the cone angle and eccentricity should be designed based on the location and size of the region where a highly enriched hydrogen atmosphere is desired to be created in the combustion chamber, i.e. the "target zone", as well as the desired swirl strength and loading capacity of the nozzle.

Specifically, the focusing swirling principle is as follows: the outlet axis of each spray hole is approximately positioned on a single-leaf hyperboloid, the direction of the rotational symmetry axis of the hyperboloid is the spray direction of the total hydrogen beam, and the intersection line (circle) of the plane perpendicular to the direction and the hyperboloid gives the concentration range of the total hydrogen beam, thereby being beneficial to realizing the design requirement of layered combustion; meanwhile, the cone angle between the outlet axis of the spray hole and the rotational symmetry axis enables the total hydrogen beam to have angular momentum along the rotational symmetry axis direction, which is beneficial to realizing the efficient mixing of hydrogen and air in a hydrogen concentration area.

As a further preferable mode, a buffer chamber is arranged between the upper end of the needle valve and the valve body.

As a further preference, a piezoelectric drive mechanism is also included for controlling the needle valve movement.

According to another aspect of the present utility model, there is provided a direct injection hydrogen internal combustion engine comprising the self-lubricating high-efficiency hybrid cold-type hydrogen injector described above.

In general, compared with the prior art, the above technical solution conceived by the present utility model mainly has the following technical advantages:

1. the lateral matching surface of the needle valve and the valve body of the hydrogen sprayer is provided with the grid-shaped grooves, lubricating oil can be automatically led into the grooves when the needle valve reciprocates to lubricate the matching surface, the air tightness of the hydrogen gas isolation lifting device is realized, the damping effect on the needle valve can be realized, and harmful vibration is reduced. The mesh structure can ensure that the matching surface is lubricated and sealed in all directions on one hand, and can prevent the needle valve from rotating on the other hand so as to prevent the two ends of the needle valve from generating extra wear.

2. Under the guidance of large reticulate patterns and reasonable size tolerance and roughness design, the surface tension of the lubricating oil can prevent the lubricating oil from leaking from the end part of the matching surface, the lubricating oil can realize self circulation, and meanwhile, the matching surface can achieve a good lubrication state.

3. The self-circulation cooling pipeline is laid in the hydrogen sprayer, so that the heat dissipation condition of the nozzle of the hydrogen sprayer can be effectively improved under the high-load working condition, the comprehensive load capacity of the nozzle to thermal stress and mechanical stress is improved according to the thin-wall strong back principle, meanwhile, hot spots (especially the nozzle) of a combustion chamber can be reduced, the abnormal combustion probability (especially the pre-combustion) is reduced, and the stability of a hydrogen supply system and a hydrogen combustion system is improved; the self-circulation cooling pipeline heat release section is arranged near the oil bag to raise the oil temperature, and the lubricating oil performance is improved while the lubricating oil circulation is promoted.

4. By specifically designing the nozzle structure, hydrogen focusing swirl flow can be generated, and under the condition that the hydrogen sprayer is suitable for the combustion chamber structure, the rapid mixing of hydrogen and air in a specific range, namely a target area (such as the vicinity of a spark plug) is facilitated, so that reliable and efficient lean stratified combustion is realized, and abnormal combustion (such as knocking in particular) is reduced. Meanwhile, due to the integrated design of the nozzle and the valve body of the hydrogen sprayer, fretting wear can be reduced, and the service life can be prolonged.

5. The hydrogen sprayer is provided with a buffer chamber, which can play a role in reducing impact.

Drawings

FIG. 1 is a schematic diagram of a self-lubricating high-efficiency hybrid cold hydrogen injector according to an embodiment of the present utility model;

FIG. 2 is a schematic view of an oil path, a large reticulate pattern and a cooling pipeline on a valve body according to an embodiment of the utility model;

FIG. 3 is a schematic view of a small cross hatch on a needle valve according to an embodiment of the present utility model;

FIG. 4 is a schematic view of a nozzle and cooling duct according to an embodiment of the present utility model;

FIG. 5 is a partial bottom view of a nozzle and cooling duct according to an embodiment of the present utility model.

The same reference numbers are used throughout the drawings to reference like elements or structures, wherein: 1-valve body, 2-needle valve, 3-piezoelectricity actuating mechanism, 4-nozzle, 41-pressure chamber, 42-orifice, 5-cooling pipeline, 6-hydrogen chamber, 7-high pressure hydrogen supply pipe, 8-oil circuit, 81-big reticulate pattern, 82-small reticulate pattern, 83-oil injection pipe, 84-oil bag, 85-connecting oil pipe, 86-connecting oil pipe, 9-buffer chamber, 1000-hydrogen injector.

Detailed Description

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model. In addition, the technical features of the embodiments of the present utility model described below may be combined with each other as long as they do not collide with each other.

The embodiment of the utility model provides a self-lubricating high-efficiency mixed cold type hydrogen injector, as shown in fig. 1, the hydrogen injector 1000 comprises a valve body 1, a needle valve 2, a piezoelectric driving mechanism 3, a nozzle 4, an oil way 8 and a cooling pipeline 5, wherein:

the upper part of the valve body 1 is provided with a piezoelectric driving mechanism 3, the middle part of the valve body is provided with a part of oil path 8, the lower part of the valve body is provided with a hydrogen cavity 6, the hydrogen cavity 6 is communicated with an external hydrogen source through a high-pressure hydrogen supply pipe 7, and the bottom end of the hydrogen cavity 6 is provided with a nozzle 4; the needle valve 2 is reciprocatingly movable up and down in the valve body 1. The oil way 8 comprises an oil pipe assembly, a large reticulate pattern 81 and a small reticulate pattern 82, and the oil pipe assembly is arranged in the valve body 1 and is communicated with the large reticulate pattern 81; the middle parts of the needle valve 2 and the valve body 1 are provided with corresponding matching surfaces, so that a large reticulate pattern 81 is positioned on the inner wall of the valve body and at the matching surface along the circumferential direction of the needle valve and is used for guiding the lubricating oil in the moving process of the needle valve; the small reticulation 82 is positioned on the outer wall of the needle valve and at the position of the matching surface in the circumferential direction of the valve body, and the capillary drainage function is utilized to ensure that the matching surface is sufficiently lubricated.

Further, as shown in fig. 2 and 3, the oil pipe assembly includes a plurality of circulation oil paths, the circulation oil paths include an oil filler pipe 83, an oil bag 84 and a connecting oil pipe 85, and the oil filler pipe 83 can timely supplement lubricating oil lost from the circulation oil paths after long-term use; the oil bag 84 is positioned at the middle section of the valve body and plays roles in storing lubricating oil and stabilizing oil pressure; in this embodiment, each circulation oil path has two oil bags 84, between the upper and lower adjacent oil bags 84, between the upper oil bag 84 and the upper end of the large reticulate pattern 81, and between the lower oil bag 84 and the lower end of the large reticulate pattern 81, all are connected through a connecting oil pipe 85, so that the connecting oil pipe 85 is connected with the oil bags 84 and the upper and lower ends of the large reticulate pattern to form a closed loop, and then the oil bags 84, the connecting oil pipe 85, the large reticulate pattern 81 and the small reticulate pattern 82 form a self-lubricating oil path capable of running for a long time, namely, a circulation oil path. The oil pipe assembly further includes a communication oil pipe 86, and the communication oil pipe 86 connects the respective oil bags adjacent to each other in the lower circumferential direction, thereby communicating the respective circulation oil paths.

Specifically, the small reticulation 82 utilizes capillary action to lead the circumferential matching surface of the needle valve even piece to be lubricated in all directions, improve friction, reduce harmful vibration and noise, and improve service life and reliability of the hydrogen sprayer. The large reticulate pattern 81 can play a role in guiding flow when the needle valve drives the lubricating oil to move up and down, so that on one hand, the above-mentioned matching surface is fully lubricated, and on the other hand, the lubricating oil in the matching surface is finally collected and recycled to the connecting oil pipe 85 in the moving direction. The small reticulate patterns 82 and the large reticulate patterns 81 have certain oil storage function at the same time so as to ensure that the matching surface is in a relatively ideal lubrication state, ensure good sealing performance of the matching surface and prevent hydrogen molecules from entering the piezoelectric driving mechanism; in addition, the reflective symmetry of the reticulation can inhibit the needle valve from rotating, and reduces the additional wear at the two ends of the needle valve. The connecting oil pipe 86 can balance and stabilize the oil pressure of each oil bag, and deposit and accumulate abrasive particles generated by long-term operation of the oil path, thereby further reducing abrasion. Preferably, the small reticulation 82 has a reticulation density greater than the reticulation density of the large reticulation 81.

Furthermore, the roughness, tolerance and the like of the matching surface are designed to ensure that no dry friction and no lubricating oil leakage occur. The roughness of the outer part of the large reticulate pattern area is the same as that of the needle valve, the nominal diameter of the needle valve is D, the included angle between the axis of the connecting oil pipe and the axis of the hydrogen sprayer is theta, and the surface tension coefficient of lubricating oil is gamma. In order to simultaneously meet the tightness and lubricity of an oil way, a base shaft is adopted for tolerance, the tightness is considered firstly, a fit clearance is set to be h, then based on D and theta, free surface pressure peak value of lubricating oil between the fit surfaces is p under the condition that the leakage flow is 0 in a plurality of needle valve cycles, whether the surface tension overpressure meets gamma/h > p (partial safety) is checked, and if the surface tension overpressure does not meet the gamma/h > p (partial safety), h is reduced to be recalculated until the above is met. Considering the lubricity again, the film thickness ratio is set to be lambda according to the elastic flow lubrication theory or the thin film lubrication theory, and the roughness of the mating surface should satisfy Ra < h/(lambda v 2). A sufficient number of needle valve cycles refer to the periodicity of the flow of the lubricant matching the needle valve movement cycle, and the free surface refers to the deformable gas-liquid interface of the upper and lower ends of the lubricant.

Further, as shown in fig. 4 and 5, the nozzle 4 is located in the valve body and is designed integrally with the valve body 1, so that fretting wear can be reduced, and the service life of the hydrogen injector can be prolonged. The nozzle 4 specifically comprises a pressure chamber 41 and a spray hole 42, the spray hole 42 is communicated with the hydrogen cavity 6 through the pressure chamber 41 on the spray hole, and hydrogen is sprayed into the combustion chamber through a plurality of spray holes with cone angle eccentricity on the pressure chamber to form hydrogen focusing swirl.

Furthermore, the plurality of spray holes 42 are uniformly circumferentially arranged, the axis of the spray hole 42 has a cone angle and an eccentric distance relative to the axis of the hydrogen sprayer, the diameter of the spray hole is small and the number of the spray holes is large, and the spray holes can be matched with hydrogen supply pressure to generate cone angle eccentric rotational flow meeting the flow requirement; the design of the cone angle and eccentricity should be tailored to the location and size of the region where a highly enriched hydrogen atmosphere is desired to be created within the combustion chamber, i.e., the "target zone", as well as the desired swirl strength and loading capacity of the nozzle. If coupled with tumble flow in the combustion chamber or the like in an appropriate manner, formation of a stratified lean combustion system can be promoted, occurrence of knocking can be reduced, emission can be reduced, and thermal efficiency can be improved.

Further, the cooling pipeline 5 is preferably a sodium-cooled pipeline, and the heat absorbing section of the sodium-cooled pipeline 5 is paved around the spray hole 42, and the heat releasing section of the sodium-cooled pipeline 5 is paved around the oil path 8. The sodium-cooled pipeline principle is similar to a heat pipe, and the temperature of a nozzle is controlled by utilizing phase change high-efficiency heat exchange, so that the cooling of the nozzle is realized, the thermal stress is reduced, the hot spot of a combustion chamber is reduced, the temperature of lubricating oil is kept, and the lubricating performance is improved. Meanwhile, the cooling pipelines around the nozzle 4 utilize the principles of 'thin-wall strong back' and 'drilling cooling', so that the comprehensive loading capacity of the nozzle 4 on thermal stress and mechanical stress is improved.

Further, the needle valve 2 is precisely and rapidly controlled to move through the piezoelectric driving mechanism 3, so that mechanical impact is reduced, and the reliability and stability of the control of the hydrogen injector are improved.

Furthermore, a buffer chamber 9 is arranged between the needle valve 2 and the valve body 1, and the buffer chamber 9 can be matched with the piezoelectric driving mechanism 3 to reduce the impact and rebound of the needle valve 2 on the valve body 1, so that the reliability of the hydrogen sprayer is improved.

In operation, under the control of the piezoelectric drive mechanism 3, the needle valve 2 moves, so that hydrogen gas is ejected from the hydrogen chamber 6 through the nozzle 4 to form an eccentric focusing swirl flow with a cone angle. The external force action of the needle valve 2 enables the lubricating oil of the oil way 8 to carry out alternating current-direct current self-circulation, an oil film is formed on the matching surface through the reticulate pattern structure, the dry friction between the needle valve and the valve body is improved, meanwhile, liquid sealing is realized, hydrogen is isolated, and the lost lubricating oil can be supplemented through the oil injection pipe 83 after long-time working. Meanwhile, the sodium cooling pipeline 5 around the spray hole 42 rises after absorbing heat during operation, and flows back to the periphery of the spray hole 42 for recirculation after being condensed near the oil way 8.

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the utility model and is not intended to limit the utility model, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the utility model are intended to be included within the scope of the utility model.

Claims (10)

1. The utility model provides a high-efficient cold type hydrogen injector that mixes of self-lubricating which characterized in that includes valve body (1), needle valve (2), nozzle (4) and oil circuit (8), wherein:

the needle valve (2) is arranged in the valve body (1), and the needle valve (2) can axially reciprocate up and down; a hydrogen cavity (6) is arranged at the lower side of the inner part of the valve body (1), and the nozzle (4) is arranged at the lower end of the hydrogen cavity (6);

the oil way (8) comprises an oil pipe assembly, a large reticulate pattern (81) and a small reticulate pattern (82), and the oil pipe assembly is arranged in the valve body (1) and is communicated with the large reticulate pattern (81); the needle valve (2) and the middle part of the valve body (1) are provided with a matching surface, the large reticulate pattern (81) is arranged at the matching surface of the valve body (1), and the small reticulate pattern (82) is arranged at the matching surface of the needle valve (2).

2. The self-lubricating high-efficiency hybrid cold type hydrogen injector according to claim 1, wherein the oil pipe assembly comprises a plurality of circulating oil paths including an oil filler pipe (83), an oil bag (84) and a connecting oil pipe (85), wherein the oil filler pipe (83) is communicated with the oil bag (84); the upper side oil bag (84) is connected with the upper end of the large reticulation (81), and the lower side oil bag (84) is connected with the lower end of the large reticulation (81) through the connecting oil pipe (85), so that a circulating oil path is formed; and all the circulating oil paths adjacent in the circumferential direction are communicated through the communicating oil pipe (86).

3. The self-lubricating high-efficiency hybrid cold-type hydrogen injector according to claim 1, characterized in that the tolerance of the matching surface of the needle valve (2) and the valve body (1) adopts a base shaft system, and the matching clearance h of the matching surface satisfies: gamma/h > p, the roughness Ra of the mating surface satisfies: ra < h/(λ v 2); wherein gamma is the surface tension coefficient of the lubricating oil in the oil passage (8), p is the free surface pressure peak value of the lubricating oil between the mating surfaces when the leakage amount is 0, and lambda is the film thickness ratio.

4. The self-lubricating high efficiency hybrid cold type hydrogen injector according to claim 1, wherein the small reticulation (82) has a reticulation density greater than that of the large reticulation (81).

5. The self-lubricating high-efficiency hybrid cold type hydrogen injector according to claim 1, further comprising a cooling pipe (5), wherein the cooling pipe (5) is internally provided with a medium capable of realizing gas-liquid conversion; the heat absorption section of the cooling pipeline (5) is paved around the nozzle (4), and the heat release section of the cooling pipeline (5) is paved around the oil path (8).

6. Self-lubricating high-efficiency hybrid cold hydrogen injector according to claim 5, characterized in that the medium in the cooling pipe (5) is sodium.

7. The self-lubricating high-efficiency hybrid cold type hydrogen injector according to claim 1, characterized in that the nozzle (4) is integrally provided in the valve body (1), the nozzle (4) comprising a pressure chamber (41) and a plurality of injection holes (42), the injection holes (42) being in communication with the hydrogen chamber (6) through the pressure chamber (41) thereon; the orifice (42) is tubular and has a cone angle and eccentricity with the hydrogen injector axis to form a focused swirl.

8. The self-lubricating high-efficiency hybrid cold type hydrogen injector according to claim 1, characterized in that a buffer chamber (9) is arranged between the upper end of the needle valve (2) and the valve body (1).

9. Self-lubricating high-efficiency hybrid cold hydrogen injector according to any one of claims 1 to 8, further comprising a piezoelectric driving mechanism (3), the piezoelectric driving mechanism (3) being adapted to control the movement of the needle valve (2).

10. A direct injection hydrogen internal combustion engine comprising a self-lubricating high efficiency hybrid cold hydrogen injector as claimed in any one of claims 1 to 9.