CN112855398A - Oil injection device and design method thereof - Google Patents

Oil injection device and design method thereof Download PDF

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Publication number
CN112855398A
CN112855398A CN202110263827.1A CN202110263827A CN112855398A CN 112855398 A CN112855398 A CN 112855398A CN 202110263827 A CN202110263827 A CN 202110263827A CN 112855398 A CN112855398 A CN 112855398A
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China
Prior art keywords
oil
plunger
central cavity
fuel
oil inlet
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CN202110263827.1A
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Chinese (zh)
Inventor
葛宪纲
王德超
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Beijing Zhongkang Zengmi Technology Co ltd
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Beijing Zhongkang Zengmi Technology Co ltd
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Priority to CN202110263827.1A priority Critical patent/CN112855398A/en
Publication of CN112855398A publication Critical patent/CN112855398A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/023—Injectors structurally combined with fuel-injection pumps characterised by the pump drive mechanical
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
    • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
    • F02M59/102—Mechanical drive, e.g. tappets or cams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
    • F02M61/10—Other injectors with elongated valve bodies, i.e. of needle-valve type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
    • F02M61/1886—Details of valve seats not covered by groups F02M61/1866 - F02M61/188
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
    • F02M61/1893—Details of valve member ends not covered by groups F02M61/1866 - F02M61/188

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

The embodiment of the invention provides an oil injection device and a design method thereof. The fuel injection device includes: a power mechanism; a plunger; the oil spraying device comprises a shell, wherein the shell comprises an opening at one end, a spraying hole at the other end and a central cavity extending linearly between the opening and the spraying hole, a plunger extends into the central cavity from the opening, and a power mechanism pushes the plunger to move towards the spraying hole so that the plunger extrudes the oil in the central cavity and sprays the oil. According to the oil injection device and the design method thereof, the number of parts is reduced, the processing and maintenance difficulty is reduced, and the control precision of the oil supply quantity is improved.

Description

Oil injection device and design method thereof
Technical Field
The invention relates to the technical field of engines, in particular to an oil injection device and a design method of the oil injection device.
Background
A technique is known in which an injection device for injecting fuel into a cylinder or a combustion chamber is provided in an engine (e.g., a diesel engine). Most of fuel injection devices or fuel injection systems in the current market comprise a fuel injection pump and a fuel injector, wherein the fuel injection pump provides high-pressure fuel for the fuel injector, and the fuel injector sprays and atomizes the high-pressure fuel. Such a mechanism results in a large number of parts of the fuel injection device, a complex assembly relationship, and a high maintenance cost, and is not favorable for maintaining the long-term stability of the fuel supply amount of each injection, and is easy to reduce the control precision of the fuel supply amount.
Disclosure of Invention
In view of the above, embodiments of the present invention are directed to providing an oil injection device and a design method of the oil injection device, which can provide a higher accuracy of oil supply amount control with a smaller number of parts.
In one aspect, the present invention provides a fuel injection apparatus comprising: a power mechanism; a plunger; the oil spraying device comprises a shell, wherein the shell comprises an opening at one end, a spraying hole at the other end and a central cavity extending linearly between the opening and the spraying hole, a plunger extends into the central cavity from the opening, and a power mechanism pushes the plunger to move towards the spraying hole so that the plunger extrudes the oil in the central cavity and sprays the oil.
According to a particular embodiment of the invention, the central cavity comprises a tapering portion with a decreasing diameter at the end where the nozzle orifice is located, the plunger abutting against a side wall of the tapering portion when the plunger is moved towards the nozzle orifice to the final position.
According to an embodiment of the invention, the plunger has a tapering portion with a decreasing diameter towards the end of the nozzle orifice, the tapering portion engaging with the tapering portion when the plunger is moved towards the nozzle orifice to a final position.
According to a specific embodiment of the invention, the housing further comprises an oil inlet passage, the oil inlet passage being in communication with the central cavity, oil entering the central cavity from the oil inlet passage when the plunger moves away from the orifice.
According to a particular embodiment of the invention, the oil inlet channel extends parallel to the central cavity on one side of the central cavity, starting from the end of the housing where the opening is located.
According to a particular embodiment of the invention, the oil intake channel comprises an oil intake lateral section extending perpendicular to the central cavity, and an oil intake dip section extending parallel to the central cavity beyond the oil intake lateral section.
According to a specific embodiment of the present invention, the housing further includes an oil return passage, the plunger includes a necked-down portion with a reduced diameter, an annular oil return chamber is formed between the necked-down portion and a side wall of the central chamber, and the oil return passage and the oil return chamber are communicated during a period of time when the plunger moves in the central chamber, so that oil in the oil return chamber can flow back through the oil return passage.
According to a specific embodiment of the invention, the oil return channel extends parallel to the central cavity on one side of the central cavity from the end of the housing where the opening is located, the oil return channel comprising an oil return transverse section extending perpendicular to the central cavity and an oil return sinker section extending parallel to the central cavity beyond the oil return transverse section.
According to a specific embodiment of the present invention, the nozzle hole includes a plurality of sub-nozzle holes uniformly distributed in a circumferential direction of the housing.
According to a specific embodiment of the present invention, the nozzle hole includes 4 to 12 sub-nozzle holes, each having a diameter of 0.2mm to 0.4 mm.
In another aspect, the present invention provides a method of designing an oil injection apparatus, including: designing a power mechanism; designing a plunger; designing a shell; and designing an oil inlet channel. The shell comprises an opening at one end, a spray hole at the other end and a central cavity extending linearly between the opening and the spray hole, the plunger extends into the central cavity from the opening, and the power mechanism pushes the plunger to move towards the spray hole so that the plunger extrudes oil in the central cavity and sprays the oil out; the shell further comprises an oil inlet channel, the oil inlet channel is communicated with the central cavity, and when the plunger moves away from the spray hole, oil enters the central cavity from the oil inlet channel. Design oil feed passageway includes: determining the oil supply flow for supplying oil to the outside through oil injection according to the displacement and the rotating speed of the engine to which the oil injection device is applied; determining an oil supply pressure difference according to a difference between the oil supply pressure and the internal pressure of the nozzle hole; and determining the length and the diameter of the oil inlet channel according to the oil supply flow and the oil supply pressure difference.
According to an embodiment of the present invention, determining a fuel supply flow rate for supplying fuel to an external environment according to a displacement and a rotation speed of an engine to which a fuel injection apparatus is applied includes: determining the fuel supply flow according to:
Q＝V×T
wherein Q represents the fuel supply flow, V represents the fuel supply amount, T represents the fuel supply time, the oil inlet amount is determined according to the displacement of the engine, and the oil inlet time is determined according to the rotating speed of the engine.
According to an embodiment of the present invention, determining the oil supply pressure difference according to a difference between the oil supply pressure and an internal pressure of the nozzle hole includes: the supply pressure difference is determined according to:
P1＝P-P2
wherein, P1Indicating the supply pressure difference, P the supply pressure, P2Indicating the internal pressure of the nozzle hole when the fuel injection device supplies fuel to the outside.
According to an embodiment of the present invention, determining the length and diameter of the oil inlet passage according to the oil supply flow rate and the oil supply pressure difference includes: the length and diameter of the oil inlet passage are determined according to the following two formulas:
Figure BDA0002971207460000031
wherein Q represents the oil supply flow, rho represents the density of oil, g represents the gravity acceleration, S represents the specific resistance of the oil inlet channel, and L represents the length of the oil inlet channel;
Figure BDA0002971207460000032
where λ represents the drag coefficient and D represents the diameter of the oil intake passage.
According to the invention, the integrally formed plunger extends from the power mechanism up to the orifice. The plunger directly provides pressure for fuel to promote the fuel to be sprayed out of the spray hole, so that the fuel pressure can be controlled more directly and accurately, and the loss of the fuel pressure in an overlong conduction path is avoided. The oil injection device integrates the oil injection pump and the oil injector together, realizes the functions of the oil injection pump and the oil injector through a small number of parts, avoids a plurality of parts (such as a needle valve, a needle valve spring and the like) in the oil injection pump and the oil injector, improves the reliability of an oil injection system, and reduces the difficulty and the cost of processing and maintenance.
Drawings
The above and other objects, features and advantages of the present application will become more apparent by describing in more detail embodiments of the present application with reference to the attached drawings. The accompanying drawings are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings, like reference characters generally refer to the same or similar parts throughout the several views, and wherein:
fig. 1 shows a schematic view of a fuel injection device according to the state of the art;
FIG. 2 is a schematic diagram illustrating a fuel injection apparatus according to an embodiment of the present disclosure;
FIG. 3 shows a schematic view of a fuel injection device according to an embodiment of the invention;
fig. 4 shows a schematic illustration of the structure of the injection device according to the exemplary embodiment of fig. 3.
Detailed Description
The present invention is described in detail below with reference to specific embodiments in order to make the concept and idea of the present invention more clearly understood by those skilled in the art. It is to be understood that the embodiments presented herein are only a few of all embodiments that the present invention may have. Those skilled in the art who review this disclosure will readily appreciate that many modifications, variations, or alterations to the described embodiments, either in whole or in part, are possible and within the scope of the invention as claimed.
As used herein, the terms "first," "second," and the like are not intended to imply any order, quantity, or importance, but rather are used to distinguish one element from another. As used herein, the terms "a," "an," and the like are not intended to mean that there is only one of the described items, but rather that the description is directed to only one of the described items, which may have one or more. As used herein, the terms "comprises," "comprising," and other similar words are intended to refer to logical interrelationships, and are not to be construed as referring to spatial structural relationships. For example, "a includes B" is intended to mean that logically B belongs to a, and not that spatially B is located inside a. Furthermore, the terms "comprising," "including," and other similar words are to be construed as open-ended, rather than closed-ended. For example, "a includes B" is intended to mean that B belongs to a, but B does not necessarily constitute all of a, and a may also include C, D, E and other elements.
Herein, some operations are described in order. However, those skilled in the art will appreciate that these operations are not necessarily performed in the order of description, nor are they performed only once throughout the flow. In actual implementation, the execution order of these operations may be reversed, some operations may be executed at the same time or different times, and the execution times of the operations may be different from each other.
The terms "embodiment," "present embodiment," "an embodiment," "one embodiment," and "one embodiment" herein do not mean that the pertinent description applies to only one particular embodiment, but rather that the description may apply to yet another embodiment or embodiments. Those of skill in the art will understand that any of the descriptions given herein for one embodiment can be combined with, substituted for, or combined with the descriptions of one or more other embodiments to produce new embodiments, which are readily apparent to those of skill in the art and are intended to be within the scope of the present invention.
In various embodiments of the present invention, a fuel injection device may refer to a device for injecting fuel into a cylinder or an intake pipe of an engine to provide fuel for combustion in the cylinder. In some embodiments of the invention, the fuel injection device may refer to a device that atomizes and distributes fuel into the combustion chamber for mixing with air. In some embodiments of the invention, the fuel injection device comprises a fuel injection pump and a fuel injector. A fuel injector may refer to a device that receives high-pressure fuel from a fuel injection pump, sprays and atomizes the fuel from nozzle holes of the fuel injector, and generally includes a nozzle. The fuel injection pump may refer to a device that applies pressure to fuel to change the fuel into high-pressure fuel to be injected from the fuel injector, and generally includes a power mechanism such as a cam or a crank.
Fig. 1 shows a prior art oil injection device. As shown in fig. 1, the oil injection device includes a needle valve body 1, a pump nozzle housing 2, a needle valve 3, a support plate 4, a spring lower seat 5, a spring support chamber 6, a needle valve spring 7, a high-pressure oil passage 8, an oil inlet 9, a plunger support body 10, a plunger 11, a plunger oil chamber 12, an oil return passage 13, an adjusting screw 14, a threaded rod 141, a hexagonal pedestal 142, a through hole 143, a limit lock nut 15, a pressure adjusting nut 16, and a gasket 17. The plunger 11 provides power for fuel oil, the fuel oil enters the oil cavity of the needle valve 3 from the plunger oil cavity 12 through the high-pressure oil duct 8, the high-pressure oil overcomes the pre-tightening force of the needle valve spring 7, the needle valve 3 is jacked upwards, and therefore the fuel oil is sprayed out from a spray hole in the tip end of the needle valve 3.
Through a great deal of experiments and researches, the inventor of the invention finds that the oil injection device has the following defects:
1. the top of the needle valve is provided with parts such as a gasket, a spring seat and a spring, the number of the parts is large, and the parts need to be precisely matched, so that the processing procedures and the processing difficulty are increased;
2. high-pressure fuel is conveyed to the nozzle through the oil duct, so that the pressure of the fuel is reduced, and the atomization effect is poor;
3. the operating time of the oil injection device is long, the gaskets are abraded, the elastic force of the spring is insufficient, the oil injection quantity is increased, and the problems of cylinder knocking, high oil consumption, poor emission and the like of an engine are caused.
An oil injection device 200 according to an embodiment of the invention is described below with reference to fig. 2.
According to the present embodiment, fuel injection device 200 includes:
a power mechanism 210;
a plunger 220;
the plunger 220 extends from the opening 231 into the central cavity 233, and the power mechanism 210 pushes the plunger 220 to move toward the nozzle hole 232 so that the plunger 220 presses and ejects the oil in the central cavity 233.
According to this embodiment, an integrally formed plunger 220 extends from the power mechanism all the way to the orifice. The plunger directly provides pressure for fuel to promote the fuel to be sprayed out of the spray hole, so that the fuel pressure can be controlled more directly and accurately, and the loss of the fuel pressure in an overlong conduction path is avoided. The oil injection device of the embodiment integrates the oil injection pump and the oil injector, realizes the functions of the oil injection pump and the oil injector through a small number of parts, avoids a plurality of parts (such as a needle valve, a needle valve spring and the like) in the oil injection pump and the oil injector, improves the reliability of an oil injection system, and reduces the difficulty and the cost of processing and maintenance.
In one embodiment, the power mechanism 210 may refer to a mechanism that powers the plunger, such as a mechanism that directly powers the plunger or a mechanism that indirectly powers the plunger. In one embodiment, the power mechanism may be a cam in an engine fuel injection system and a transmission component (such as a slider, a spring, etc.) from the cam to the plunger, and the rotation of the cam directly or indirectly provides forward propulsion power to the plunger; or a crankshaft in an engine fuel injection system or other systems, and the rotation of the crankshaft indirectly provides the forward propelling power for the plunger through a rocker or other transmission component.
In one embodiment, the plunger 220 may refer to a cylindrical part that squeezes and draws fuel by reciprocating motion. In one embodiment, the plunger may refer to an integral component having one end capable of contacting the actuating mechanism and the other end capable of contacting the nozzle hole.
In one embodiment, the housing 230 may refer to a housing of a fuel injection device for containing fuel, plungers, etc. In one embodiment, the opening of the housing may refer to a larger opening into the interior space of the housing, which substantially determines the size (e.g., diameter) of the interior space of the housing from which the primary components (e.g., the plunger) inside the housing may enter the interior space of the housing. In one embodiment, the nozzle may be a hole for injecting fuel, and one end of the nozzle is connected to the inner space (oil chamber) of the housing, and the other end is connected to the external environment (e.g., cylinder). In one embodiment, the central cavity may refer to a cavity located at a central position of the housing (e.g., an axis of the central cavity coincides with an axis of the housing), which is a main body of the housing inner space for accommodating the plunger and the fuel. In one embodiment, the central cavity extends linearly between the opening and the nozzle hole, which may mean that the central axis of the central cavity coincides with the central axis of the opening and the central axis of the nozzle hole, so that the central cavity space between the opening and the nozzle hole is linearly communicated; it may also mean that the space through which the straight line connecting the opening and the nozzle hole passes is part of the central chamber, so that an object (e.g. a plunger) that reciprocates linearly within the central chamber can be pushed from the opening all the way to the nozzle hole. In one embodiment, the housing includes an opening at one end, a nozzle at the other end, and a central cavity extending linearly between the opening and the nozzle, which may mean that the housing has an open end with a larger sized opening for insertion of the plunger and a (substantially) closed end with a smaller sized nozzle; the fuel in the shell can be sprayed out of the spray hole through the extrusion of the plunger, and no fuel flows out if no extrusion is carried out; the body of the interior space from the opening to the orifice is a central chamber that extends linearly between the open and closed ends of the housing.
In an embodiment, the plunger extends from the opening into the central cavity, which may mean that the plunger comprises a portion inside the central cavity and a portion outside the central cavity, which portions extend continuously in at least one direction, and which portions may be integrally formed.
In one embodiment, the power mechanism pushes the plunger to move towards the spray hole so that the plunger extrudes and sprays the oil in the central cavity, which may mean that the power for spraying the fuel from the spray hole (completely) comes from the propulsion of the plunger, and the propulsion of the plunger (completely) is driven by the power mechanism, so that the power of the power mechanism acts on the fuel as directly as possible, and the conduction through complicated and tortuous pipelines or various parts is avoided; the purpose of the injection is to supply oil (e.g. fuel) to the environment (e.g. cylinders, combustion chambers, intake pipes, etc.), which is also the basic function of the injection device.
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, central bore 333 includes a tapered portion 334 with a decreasing diameter at the end where orifice 332 is located, and plunger 320 abuts against a sidewall of tapered portion 334 as plunger 320 moves toward orifice 332 to a final position.
According to the embodiment, the tapered part of the central cavity is arranged at the spray hole, so that the fuel pressure can be gradually concentrated to the position of the spray hole, the thrust of the plunger on the fuel is utilized as high as possible, and more thrust is prevented from being lost on the side wall of the central cavity. The plunger abutting against the side wall of the tapered portion means that the plunger can be directly advanced to the vicinity of the nozzle hole, and such a plunger can directly act on the fuel to be injected, and the pressure (fuel supply pressure) applied to the fuel and the fuel injection amount thereof can be more accurately controlled.
In one embodiment, the taper may refer to a portion or segment of the central lumen that tapers in diameter. In an embodiment, the tapered portion may be a space portion directly connected to the nozzle hole, and it may be a funnel-shaped portion, and the bottom of the funnel is the nozzle hole. In one embodiment, the end of the central cavity where the nozzle hole is located includes a tapered portion with a gradually decreasing diameter, which may mean that the central cavity includes a first end and a second end opposite to each other, the first end is connected with the nozzle hole, and the second end is connected with the opening of the housing; in the end section of the first end, the diameter of the central cavity is gradually reduced to form a funnel-shaped space part, and the space part is a tapered part.
In an embodiment, when the plunger moves towards the nozzle hole to the final position, the plunger abuts against the side wall of the tapered portion, which may mean that when the plunger moves towards the inside of the housing to the final end (dead point), the plunger can contact the inner wall of the housing at the tapered portion, which describes the position of the plunger on the one hand, the plunger is arranged at the position next to the tapered portion or the nozzle hole inside the housing, and describes the length of the plunger on the other hand, and the plunger can extend to the tapered portion (nozzle).
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the plunger 320 has a tapered portion 321 with a gradually decreasing diameter toward the end of the nozzle hole 332, and when the plunger 320 moves to the final position toward the nozzle hole 332, the tapered portion 321 is engaged with the tapered portion 334.
According to the embodiment, the tail end of the plunger forms the tapered part matched with the tapered part, so that the space part of the central cavity near the spray hole can be extruded to the minimum, thereby extruding out fuel as much as possible and avoiding more fuel from remaining in the central cavity. The cooperation of convergent portion and tapering portion also can provide more reliable backstop effect for the plunger, and stress concentration when avoiding the backstop is on the small part area of shells inner wall.
In one embodiment, the taper may refer to a generally conical sharp portion of the plunger tip that tapers in diameter in a manner that includes a continuous smooth reduction, a discontinuous reduction, and a stepped reduction. In one embodiment, the plunger has a tapered portion with a gradually decreasing diameter at the end facing the nozzle hole, which may mean that the plunger has a first end and a second end opposite to each other, the first end is close to or facing the nozzle hole, and the second end is close to or facing the opening of the housing; the section of the plunger near the first end forms a tip portion with a gradually reduced diameter.
In one embodiment, when the plunger moves towards the nozzle hole to the final position, the tapered portion is matched with the tapered portion, which may mean that the plunger can move back and forth in two directions towards the nozzle hole and away from the nozzle hole, and when the plunger moves towards the nozzle hole, the plunger can move until the tail end of the plunger abuts against the side wall (inner wall of the shell) of the central cavity around the nozzle hole; at the moment, the central cavity around the spray hole is a tapered part, and the tail end of the plunger correspondingly forms a tapered part; when convergent portion and tapering portion lean on each other, the pointed end of tapering portion can contact the thin end of convergent portion, and the root (butt) of tapering portion can contact the butt of tapering portion, and the toper lateral wall of tapering portion can contact the infundibulate lateral wall of tapering portion.
Another embodiment according to the present invention is described below with reference to fig. 2, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, housing 230 further includes an oil inlet passage 234, oil inlet passage 234 communicating with central bore 233, oil entering central bore 233 from oil inlet passage 234 as plunger 220 moves away from orifice 232.
According to this embodiment, through setting up oil feed passageway, can provide an independent, stable route for fuel gets into the central chamber for fuel can be according to the motion source of plunger constantly inflow in the central chamber.
In one embodiment, the oil inlet passage may refer to a passage that allows fuel to enter the central cavity for ram compression. In one embodiment, the oil inlet passage may be connected to an external oil source. In an embodiment, the housing comprises an oil inlet channel, which may mean that the oil inlet channel is a (separate) space formed within the housing, e.g. formed in a solid part between an outer wall and an inner wall of the housing. In one embodiment, the oil inlet passage is in communication with the central chamber, which may mean that the space of the oil inlet passage is in communication with (in some cases) the space in the central chamber, such that fuel (in some cases) can flow from the source of oil through the oil inlet passage into the central chamber for compression by the plunger.
In one embodiment, when the plunger moves away from the nozzle hole, oil enters the central cavity from the oil inlet channel, which may mean that when the plunger moves away from the nozzle hole toward the opening of the housing, oil flows from the oil source into the oil inlet channel due to a negative pressure in the central cavity or due to the pushing of the oil source, and then flows from the oil inlet channel into the central cavity.
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the oil inlet passage 334 extends from the end of the housing 330 where the opening 331 is located, in parallel to the central chamber 333, on one side of the central chamber 333.
According to this embodiment, the oil feed passageway is parallel with the central cavity, can be so that the oil in the oil feed passageway can steadily enter the central cavity in an orderly manner, avoids oil excessive inrush into central cavity.
In an embodiment, the end portion of the housing where the opening is located may mean that the housing includes first and second opposite ends, the first end is provided with the nozzle hole, the second end is provided with the opening, and the end portion where the opening of the housing is located is the second end opposite to the first end provided with the nozzle hole. In one embodiment, extending parallel to the central lumen may mean that the central lumen is generally elongate in shape with a central axis along its length, extending parallel to the central axis, i.e., extending parallel to the central lumen. In one embodiment, one side of the central cavity may refer to a side in a direction perpendicular to a central axis of the central cavity. For example, the central axis of the central chamber extends in the up-down direction, and then one side of the central chamber may refer to a side in the left-right direction of the central chamber.
In an embodiment, the oil inlet passage extends from the end of the housing where the opening is located to one side of the central cavity in parallel with the central cavity, which may mean that (a part of) the oil inlet passage extends from an end surface around the opening of the housing to the direction of the nozzle hole, so that the central axis of the oil inlet passage is parallel to the central axis of the central cavity.
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to this embodiment, the oil feed passage 334 includes an oil feed lateral section 335 extending perpendicular to the central chamber 333, and an oil feed dip section 336 extending parallel to the central chamber 333 beyond the oil feed lateral section.
According to the embodiment, the oil inlet transverse section is arranged, so that oil can be allowed to smoothly enter the central cavity; through setting up the oil feed and sinking the section, can avoid forming the vortex at the intersection (for example right angle turn portion) between oil feed passageway main part and the horizontal section of oil feed and then produce the vortex and hinder, influence the smooth entering of fuel.
In an embodiment, the oil inlet lateral section may refer to a laterally (perpendicular to the central axis of the central cavity) extending portion of the oil inlet passage, one end of which connects to a section of the oil inlet passage extending parallel to the central cavity and the other end of which connects to the central cavity. In an embodiment, extending perpendicular to the central cavity may mean that the central cavity has an elongated shape, the length direction of which is the extending direction of the central cavity, and extends perpendicular to the extending direction, i.e. perpendicular to the central cavity.
In one embodiment, the oil inlet sinking section may refer to a tail section of a portion of the oil inlet passage extending parallel to the central cavity, one end of which connects to the intersection of the main body of the oil inlet passage and the oil inlet transverse section, and the other end of which extends into the housing, so that the main body of the oil inlet passage sinks a portion relative to the position of the oil inlet transverse section. In one embodiment, extending beyond the oil inlet transverse section may refer to extending along an extending direction of the main body of the oil inlet passage (i.e. parallel to the central cavity), and continuing to extend forward by a section when extending to a junction of the main body of the oil inlet passage and the oil inlet transverse section.
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the housing 330 further includes an oil return passage 337, the plunger 320 includes a necked-down portion 322 having a reduced diameter, an annular oil return chamber 340 is formed between the necked-down portion 322 and a side wall of the central chamber 333, and the oil return passage 337 and the oil return chamber 340 communicate during a period of time when the plunger 320 moves in the central chamber 333 such that oil in the oil return chamber 340 can flow back through the oil return passage 337.
According to the embodiment, the oil can flow back by arranging the oil return channel and the related passages, so that the excessive oil pressure in the central cavity can be avoided, and on the other hand, the returned oil can be used for cooling related parts (such as the shell and the plunger).
In one embodiment, the oil return passage may be a passage through which fuel within the central chamber flows back (e.g., toward an oil source or elsewhere, rather than being ejected). In an embodiment, the housing comprises an oil return channel, which may mean that the oil return channel is a (separate) space formed within the housing, e.g. in a solid part between an outer wall and an inner wall of the housing.
In one embodiment, a constriction may refer to a section of a cylindrical or rod-like member having one diameter or transverse dimension that is reduced relative to the other portions of the two sides. In one embodiment, the oil return chamber may refer to a cavity for providing a passage or a receiving place for returning oil. In one embodiment, the constriction forms an annular oil return chamber with the side wall of the central chamber, which may mean that the outer wall of the plunger abuts or contacts the side wall of the central chamber (inner wall of the housing), and when the plunger forms the constriction with a reduced diameter, the constriction is recessed with respect to the side wall of the central chamber, so as to form an annular space, i.e., the oil return chamber for accommodating the returned fuel oil.
In an embodiment, the oil return passage is communicated with the oil return cavity within a period of time when the plunger moves in the central cavity, so that oil in the oil return cavity can flow back through the oil return passage.
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the oil return passage 337 extends from the end of the housing 330 where the opening 331 is located on one side of the central cavity 333 in parallel with the central cavity 333, and the oil return passage 337 includes an oil return lateral section 338 extending perpendicular to the central cavity 333 and an oil return depressed section 339 extending parallel to the central cavity 333 beyond the oil return lateral section 338.
According to the embodiment, the oil return passage is parallel to the central cavity, so that oil in the oil return passage can smoothly and orderly leave the central cavity, and the oil is prevented from excessively rushing out of the central cavity; by arranging the oil return transverse section, oil can be allowed to smoothly leave the central cavity; by arranging the oil return sinking section, vortex can be prevented from being formed at the intersection (such as a right-angle turning part) between the oil return channel main body and the oil return transverse section, so that vortex resistance is avoided, and the smooth leaving of fuel oil is influenced.
In an embodiment, the oil return passage extends from the end of the housing where the opening is located to one side of the central cavity in parallel with the central cavity, which may mean that (a part of) the oil return passage extends from an end surface around the opening of the housing to the direction of the nozzle hole, such that the central axis of the oil return passage is parallel with the central axis of the central cavity.
In an embodiment, the oil return transverse section may refer to a transversely (perpendicular to the central axis of the central cavity) extending portion of the oil return channel, one end of which is connected to a section of the oil return channel extending parallel to the central cavity and the other end of which is connected to the central cavity.
In an embodiment, the oil return sinking section may refer to a tail section of a portion of the oil return passage extending parallel to the central cavity, one end of which connects to an intersection of the main body of the oil return passage and the oil return transverse section, and the other end of which extends to the inside of the housing, so that the position of the main body of the oil return passage relative to the oil return transverse section is sunk by a portion. In an embodiment, the extension beyond the oil return transverse section may refer to extending along an extension direction of the main body of the oil return passage (i.e. parallel to the central cavity), and continuing to extend forward when extending to a junction of the main body of the oil return passage and the oil return transverse section.
Another embodiment according to the present invention is described below with reference to fig. 3, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the injection hole 332 includes a plurality of sub-injection holes uniformly distributed in the circumferential direction of the housing.
According to the embodiment, the injection hole comprises a plurality of sub-injection holes, so that fuel can be injected more uniformly, and the atomization effect is enhanced.
In one embodiment, the sub-orifice is a component of the orifice relative to the orifice; the spray orifice may be a single spray channel (hole) or a spray orifice (for example, a shower head) formed by a plurality of mutually independent spray channels; the sub-nozzle may be a nozzle separately forming a discharge channel, different sub-nozzles are independent from each other, and the sub-nozzle may be, for example, a single circular hole.
In one embodiment, the housing is uniformly distributed in the circumferential direction, which may mean that the housing is substantially in an elongated shape, the length direction of the housing is axial (or the central axis direction of the central cavity of the housing is axial), and the direction of rotation around the axial direction is circumferential; evenly distributed in the circumferential direction, i.e. evenly distributed on a circle around the central axis of the housing.
In one embodiment, the nozzle hole includes a plurality of sub nozzle holes uniformly distributed in the circumferential direction of the housing, which may mean that the nozzle hole is formed of a plurality of sub nozzle holes, each of which individually forms an ejection port or a hole, and the sub nozzle holes are uniformly distributed in a circle around the central axis of the housing.
The following describes another embodiment of the present invention, which is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the nozzle hole 332 includes 4 to 12 sub-nozzle holes, each having a diameter of 0.2mm to 0.4 mm.
According to the present embodiment, by limiting the number and size of the sub nozzle holes, the sprayed oil can be uniformly dispersed in the combustion chamber, a good atomization effect can be produced, and the oil in the central chamber can be brought to the correct pressure so as to promote the spraying and atomization of the oil. The number and size of such sub-orifices are adapted to the design of the plunger of the present application (e.g., the diameter or the advancing speed of the plunger), so that proper operation of the injection device can be well ensured.
In one embodiment, the nozzle holes include 6 to 10 sub-nozzle holes, each having a diameter of 0.25mm to 0.35 mm. In one embodiment, the nozzle holes include 8 sub-nozzle holes, each having a diameter of 0.3 mm.
Another embodiment according to the present invention is described below with reference to fig. 2 and 3, where this embodiment is a specific example of the embodiment of fig. 1 and may include one or more features of one or more of all of the embodiments described above.
According to the present embodiment, the fuel injection device 300 mainly includes a power unit (not shown), a plunger 320, and a housing 330. The plunger 320 is inserted into the housing 330 and reciprocates in the housing 330. The space in the housing 330 for accommodating the plunger 320 is a central cavity, so that the position of the plunger 320 in the housing 330 is the central (axial) position of the housing 330. The housing 330 is a column-shaped body that rotates around the central axis, the plunger 320 is a column-shaped body that rotates around the central axis, and the central axis of the housing 330, the central axis of the central chamber, and the central axis of the plunger 320 coincide with each other.
The plunger 320 can be inserted through an opening at one end of the housing 330 to a nozzle at the other end of the housing 330 and extrude substantially all of the oil in the central cavity. The plunger 320 terminates in a tapered tapering portion 321, the central cavity terminates in a funnel-shaped tapering portion 333, and the shape of the tapering portion 321 and the shape of the tapering portion 333 are complementary such that when the plunger 320 is moved to the terminal position (as shown in fig. 4), the outer surface of the tapering portion 321 contacts the side wall of the tapering portion 333 (the inner surface of the housing 330).
The plunger 320 has a constriction 322 at a middle position, the constriction 322 having a diameter slightly smaller than the diameter of the plunger 320 body, so that the plunger 320 forms a return oil chamber 340 at the location of the constriction 322.
The housing 330 is provided with an oil intake passage 334 on the right side as viewed in fig. 3 and 4. The oil feed passage 334 includes a main body portion, an oil feed lateral section 335, and an oil feed dip section 336. An oil intake cross section 335 extends left from the oil intake passage 334 into the central cavity. The oil intake dip section 336 extends from the lower end of the main body portion further into the housing 330 beyond the location of the oil intake cross section 335.
The housing 330 is provided with an oil return passage 337 at the left side as viewed in fig. 3 and 4. The oil return passage 337 includes a main body portion, an oil return lateral section 338 and an oil return dip section 339. The oil return lateral segment 338 is within a central cavity extending rightward from the oil return passage 337. The oil return dip section 339 continues from the lower end of the main body portion beyond the position of the oil return lateral section 338 further into the housing 330.
When the plunger 320 moves to a position such as that shown in fig. 4, a certain amount of fuel may accumulate in the return chamber 340. At this time, the oil return cavity 340 is communicated with the oil return channel 337, and the fuel in the oil return cavity 340 can flow out through the oil return channel 337, so as to cool the components.
A method of designing an injection device according to an embodiment of the invention is described below.
According to the present embodiment, the method of designing the fuel injection device includes:
designing a power mechanism;
designing a plunger;
designing a shell, wherein the shell comprises an opening at one end, a spray hole at the other end and a central cavity extending linearly between the opening and the spray hole, a plunger extends into the central cavity from the opening, and a power mechanism pushes the plunger to move towards the spray hole so that the plunger extrudes oil in the central cavity and sprays the oil out; the shell further comprises an oil inlet channel, the oil inlet channel is communicated with the central cavity, and when the plunger moves away from the spray hole, oil enters the central cavity from the oil inlet channel;
design oil feed passageway includes:
determining the direction of flow to the outside by injection of fuel, according to the displacement and speed of the engine to which the device is applied
The oil supply flow rate of the oil supply;
determining an oil supply pressure difference according to a difference between the oil supply pressure and the internal pressure of the nozzle hole;
and determining the length and the diameter of the oil inlet channel according to the oil supply flow and the oil supply pressure difference.
According to this embodiment, through the size of confirming the oil feed passageway according to the relevant parameter of engine, can make the design of oil feed passageway accord with the design index of engine more to the effect that the oil feed passageway that makes the design can exert oil feed more well makes the size of oil feed passageway and the design parameter phase-match of engine.
In one embodiment, the fuel supply flow rate for supplying fuel to the outside by fuel injection may be an amount of fuel injected per unit time when the fuel injection device injects fuel to the outside (a cylinder, a combustion chamber, or an intake pipe).
In one embodiment, the oil supply flow rate for supplying oil to the outside through oil injection is determined according to the displacement and the rotating speed of the engine to which the oil injection device is applied, which may mean that the oil supply flow rate is obtained through a specific calculation formula or a table look-up according to the displacement and the rotating speed of the engine to which the oil injection device is applied; or estimating the oil supply flow according to the discharge capacity and the rotating speed of the engine to which the oil injection device is applied and experience; it may also mean that one or more intermediate values are obtained according to the displacement and the rotation speed of the engine to which the fuel injection device is applied, and the fuel supply flow is obtained according to these intermediate values.
In an embodiment, the determining the oil supply pressure difference according to the difference between the oil supply pressure and the internal pressure of the nozzle hole may be subtracting the oil supply pressure from the internal pressure of the nozzle hole to obtain the oil supply pressure difference.
In one embodiment, the length and the diameter of the oil inlet channel are determined according to the oil supply flow and the oil supply pressure difference, which may mean that the length and the diameter of the oil inlet channel are obtained through a specific formula or a table look-up according to the oil supply flow and the oil supply pressure difference; or estimating the length and the diameter of the oil inlet channel according to the oil supply flow and the oil supply pressure difference and experience; the method can also be characterized in that one or more intermediate numerical values are obtained according to the oil supply flow and the oil supply pressure difference, and the length and the diameter of the oil inlet channel are obtained according to the intermediate numerical values.
The following describes another embodiment of the present invention, which is a specific example of the above-mentioned embodiment of the design method, and may include one or more features of one or more of all of the above-mentioned embodiments.
According to the present embodiment, determining the fuel supply flow rate to the outside according to the displacement and the rotation speed of the engine to which the fuel injection device is applied includes:
determining the fuel supply flow according to:
Q＝V×T
wherein Q represents the fuel supply flow, V represents the fuel supply amount, T represents the fuel supply time, the oil inlet amount is determined according to the displacement of the engine, and the oil inlet time is determined according to the rotating speed of the engine.
According to the embodiment, by calculating the oil supply flow, a solid foundation and a reliable basis can be provided for the size calculation of the oil inlet channel, so that the designed oil inlet channel is more in line with relevant parameters of the engine.
In one exemplary embodiment, the fuel supply rate may be an amount (e.g., expressed by mass or volume) of fuel supplied to the environment (cylinder or combustion chamber) by the fuel injection device per unit time.
In one embodiment, the fuel supply quantity may be a total quantity (e.g., expressed by mass or volume) of all fuel injected by the fuel injection device per injection.
In one embodiment, fueling time may refer to the time it takes for a fuel injector to inject fuel each time. In one embodiment, the oil supply time may refer to all or a part of the time taken for the entire process of moving the plunger from the top dead center (the moving position where the plunger is farthest from the nozzle hole) to the bottom dead center (the moving position where the plunger is closest to or contacts the nozzle hole).
In one embodiment, the oil inlet amount is determined according to the displacement of the engine, which may mean that the displacement of the engine determines the oil amount required by each combustion of the cylinder, and the oil supply amount provided to the cylinder by the oil injection device can be determined according to the oil amount. In an embodiment, the oil inlet time is determined according to the rotating speed of the engine, which may mean that the rotating speed of the engine determines the reciprocating frequency of the plunger, and the oil supply time can be determined according to the time required by the plunger to move towards the nozzle hole each time.
The following describes another embodiment of the present invention, which is a specific example of the above-mentioned embodiment of the design method, and may include one or more features of one or more of all of the above-mentioned embodiments.
According to the present embodiment, determining the fuel supply pressure difference according to the difference between the fuel supply pressure and the internal pressure of the injection hole includes:
the supply pressure difference is determined according to:
P1＝P-P2
wherein, P1Indicating the supply pressure difference, P the supply pressure, P2Indicating the internal pressure of the nozzle hole when the fuel injection device supplies fuel to the outside.
According to the embodiment, the oil supply pressure difference is obtained through the difference value between the oil supply pressure and the internal pressure, and the pressure dissipated in the fuel oil can be accurately obtained so as to calculate the relevant numerical value of the oil passage.
In one embodiment, the fueling pressure may refer to the pressure that the power component needs to apply in order to fuel the cylinder or combustion chamber. In one embodiment, the supply pressure may be the pressure to which the fuel at the inlet of the oil inlet passage is subjected.
In one embodiment, the internal pressure of the nozzle hole when the fuel injection device supplies fuel to the outside may be a pressure at the nozzle hole (nozzle) when fuel is injected from the nozzle hole. In an embodiment, the internal pressure of the nozzle hole when the fuel injection device supplies fuel to the outside may be pressure inside the nozzle hole when fuel is not injected from the nozzle hole.
The following describes another embodiment of the present invention, which is a specific example of the above-mentioned embodiment of the design method, and may include one or more features of one or more of all of the above-mentioned embodiments.
According to this embodiment, according to fuel flow and fuel supply pressure differential, confirm the length and the diameter of oil feed passageway, include:
the length and diameter of the oil inlet passage are determined according to the following two formulas:
Figure BDA0002971207460000191
wherein Q represents the oil supply flow, rho represents the density of oil, g represents the gravity acceleration, S represents the specific resistance of the oil inlet channel, and L represents the length of the oil inlet channel;
Figure BDA0002971207460000192
where λ represents the drag coefficient and D represents the diameter of the oil intake passage.
According to this embodiment, calculate the length and the diameter of oil feed passageway through two formulas, can accurately obtain fast under different design parameter, the size change relation of oil feed passageway. The length and the diameter of the oil inlet channel are determined according to the oil supply flow and the oil supply pressure difference, so that the size of the oil inlet channel can better meet the design condition of the oil injection device, and the designed oil inlet channel can normally and well run.
In one embodiment, the length of the oil inlet passage may refer to the length of the oil inlet passage body (e.g., excluding the oil inlet lateral section and the oil inlet sinking section), such as the length L shown in fig. 4.
In one embodiment, the drag coefficient is a quantity related to the roughness of the inner wall of the oil intake passage. After determining the roughness, the drag coefficient can be obtained by looking up the table. In one embodiment, the roughness is typically 0.8.
In an embodiment, the diameter of the oil inlet passage may refer to the diameter of the oil inlet passage body (e.g., excluding the oil inlet lateral section and the oil inlet sink section), such as diameter D shown in fig. 4.
The concepts, principles and concepts of the invention have been described above in detail in connection with specific embodiments (including examples and illustrations). It will be appreciated by persons skilled in the art that embodiments of the invention are not limited to the specific forms disclosed above, and that many modifications, alterations and equivalents of the steps, methods, apparatus and components described in the above embodiments may be made by those skilled in the art after reading this specification, and that such modifications, alterations and equivalents are to be considered as falling within the scope of the invention. The scope of the invention is only limited by the claims.

Claims (10)

1. A fuel injection apparatus, comprising:
a power mechanism;
a plunger;
the plunger extends into the central cavity from the opening, and the power mechanism pushes the plunger to move towards the jet hole so that the plunger extrudes the oil in the central cavity and ejects the oil.
2. The fuel injection device of claim 1, wherein the central bore includes a tapered portion of decreasing diameter at an end of the nozzle bore, the plunger abutting a sidewall of the tapered portion when the plunger moves toward the nozzle bore to a final position.
3. The oil injection device of claim 2, wherein the plunger has a tapered tip portion with a diameter that gradually decreases toward a tip end of the nozzle hole, the tapered tip portion engaging with the tapered portion when the plunger moves to a final position toward the nozzle hole.
4. The oil injection apparatus of claim 1, wherein the housing further includes an oil inlet passage in communication with the central bore, oil entering the central bore from the oil inlet passage when the plunger moves away from the orifice.
5. The oil injection device according to claim 4, wherein the oil inlet passage extends from an end of the housing where the opening is located, in parallel to the central cavity on one side of the central cavity; the oil inlet channel comprises an oil inlet transverse section and an oil inlet sinking section, wherein the oil inlet transverse section is perpendicular to the central cavity in extension, and the oil inlet sinking section is parallel to the central cavity in extension and exceeds the oil inlet transverse section.
6. The oil injection apparatus of claim 1, wherein the housing further includes an oil return passage, the plunger includes a necked-down portion having a reduced diameter, an annular oil return chamber is formed between the necked-down portion and a side wall of the central chamber, and the oil return passage communicates with the oil return chamber during a period of time in which the plunger moves in the central chamber, so that oil in the oil return chamber can flow back through the oil return passage.
7. The oil injection apparatus of claim 6, wherein the oil return passage extends parallel to the central cavity on one side of the central cavity from an end of the housing where the opening is located, the oil return passage including an oil return lateral section extending perpendicular to the central cavity, and an oil return dip section extending parallel to the central cavity beyond the oil return lateral section.
8. The oil injection device according to any one of claims 1 to 7, wherein the nozzle hole includes a plurality of sub-nozzle holes that are evenly distributed in a circumferential direction of the housing; wherein the nozzle holes comprise 4 to 12 sub nozzle holes, and the diameter of each sub nozzle hole is 0.2mm to 0.4 mm.
9. A method of designing a fuel injection apparatus, comprising:
designing a power mechanism;
designing a plunger;
designing a shell, wherein the shell comprises an opening at one end, a spray hole at the other end and a central cavity extending linearly between the opening and the spray hole, the plunger extends into the central cavity from the opening, and the power mechanism pushes the plunger to move towards the spray hole so as to enable the plunger to extrude the oil in the central cavity and spray the oil out; the shell further comprises an oil inlet channel, the oil inlet channel is communicated with the central cavity, and when the plunger moves away from the spray hole, oil enters the central cavity from the oil inlet channel;
design the oil feed passageway includes:
determining the oil supply flow for supplying oil to the outside through oil injection according to the displacement and the rotating speed of the engine to which the oil injection device is applied;
determining an oil supply pressure difference according to a difference between the oil supply pressure and the internal pressure of the nozzle hole;
and determining the length and the diameter of the oil inlet channel according to the oil supply flow and the oil supply pressure difference.
10. The method of designing a fuel injection apparatus according to claim 9, wherein the determining a supply flow rate of supply of fuel to the outside according to a displacement and a rotation speed of an engine to which the fuel injection apparatus is applied includes:
determining the fuel supply flow according to:
Q＝V×T
q represents oil supply flow, V represents oil supply amount, T represents oil supply time, the oil inlet amount is determined according to the displacement of the engine, and the oil inlet time is determined according to the rotating speed of the engine;
wherein the determining the oil supply pressure difference according to the difference between the oil supply pressure and the internal pressure of the nozzle hole includes:
the supply pressure difference is determined according to:
P1＝P-P2
wherein, P1Indicating the supply pressure difference, P the supply pressure, P2The internal pressure of the spray hole is represented when the oil injection device supplies oil to the outside;
wherein, according to fuel feeding flow with the fuel feeding pressure differential, confirm oil feed channel's length and diameter includes:
determining the length and diameter of the oil inlet channel according to the following two formulas:
Figure FDA0002971207450000031
wherein Q represents the oil supply flow, ρ represents the density of oil, g represents the gravity acceleration, S represents the specific resistance of the oil inlet channel, and L represents the length of the oil inlet channel;
Figure FDA0002971207450000032
wherein λ represents a drag coefficient and D represents a diameter of the oil intake passage.
CN202110263827.1A 2021-03-11 2021-03-11 Oil injection device and design method thereof Pending CN112855398A (en)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351288A (en) * 1964-03-25 1967-11-07 Cummins Engine Co Inc Fuel injector
GB1221531A (en) * 1967-06-08 1971-02-03 Ffsa Improvements in and relating to fuel injection systems on internal combustion engines
CN101059112A (en) * 2006-04-20 2007-10-24 现代自动车株式会社 Injector for diesel engine
CN102734032A (en) * 2012-06-19 2012-10-17 浙江大学 High-pressure air-assisted fuel oil spray device
CN102812232A (en) * 2010-02-18 2012-12-05 欧陆汽车有限责任公司 High-pressure fuel injection valve for an internal combustion engine
CN107575327A (en) * 2017-10-20 2018-01-12 西华大学 A kind of electric control single pump engine and its control method
CN214464615U (en) * 2021-03-11 2021-10-22 北京中康增材科技有限公司 Oil injection device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351288A (en) * 1964-03-25 1967-11-07 Cummins Engine Co Inc Fuel injector
GB1221531A (en) * 1967-06-08 1971-02-03 Ffsa Improvements in and relating to fuel injection systems on internal combustion engines
CN101059112A (en) * 2006-04-20 2007-10-24 现代自动车株式会社 Injector for diesel engine
CN102812232A (en) * 2010-02-18 2012-12-05 欧陆汽车有限责任公司 High-pressure fuel injection valve for an internal combustion engine
CN102734032A (en) * 2012-06-19 2012-10-17 浙江大学 High-pressure air-assisted fuel oil spray device
CN107575327A (en) * 2017-10-20 2018-01-12 西华大学 A kind of electric control single pump engine and its control method
CN214464615U (en) * 2021-03-11 2021-10-22 北京中康增材科技有限公司 Oil injection device

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