CN116857096B - Low-oil-return electric-control oil injector with variable oil injection rule - Google Patents

Low-oil-return electric-control oil injector with variable oil injection rule Download PDF

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Publication number
CN116857096B
CN116857096B CN202311127431.XA CN202311127431A CN116857096B CN 116857096 B CN116857096 B CN 116857096B CN 202311127431 A CN202311127431 A CN 202311127431A CN 116857096 B CN116857096 B CN 116857096B
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cavity
control
valve
pressure
control valve
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CN116857096A (en
Inventor
赵建辉
魏荣强
卢相东
杨津韬
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Harbin Engineering University
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Harbin Engineering University
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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
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • 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
    • F02M61/161—Means for adjusting injection-valve lift
    • 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
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0017—Valves characterised by the valve actuating means electrical, e.g. using solenoid using electromagnetic operating means

Abstract

The invention belongs to the technical field of diesel engines, and discloses a low-oil return electric control oil injector with a variable oil injection rule, which comprises an electromagnetic valve body, an electromagnetic control valve assembly, a control valve body and a needle valve injection assembly; the outer wall of the control valve of the electromagnetic control valve assembly is propped against the inner wall of the control valve body to form cylindrical surface sealing, and a certain gap exists between the outer wall of the needle valve injection assembly and the inner wall of the nozzle. According to the invention, under the rectangular oil injection rule, when a small current is introduced into the electromagnetic control valve assembly, high-pressure fuel flows through the primary control fuel flow path and the oil injection flow path of the needle valve injection assembly; when large current is introduced, high-pressure fuel flows through the primary control fuel flow path, the secondary control fuel flow path and the fuel injection flow path of the needle valve injection assembly; when the boot-shaped fuel injection is performed in a regular injection mode, when small current is introduced, high-pressure fuel flows through a primary control fuel flow path and a fuel injection flow path of a needle valve injection assembly; when a large current is supplied, high-pressure fuel flows through the secondary control fuel flow path and the needle valve injection assembly fuel injection flow path.

Description

Low-oil-return electric-control oil injector with variable oil injection rule
Technical Field
The invention belongs to the technical field of diesel engines, and particularly relates to a low-oil-return electric control oil sprayer with a variable oil spraying rule.
Background
The electronic control fuel injector is used as an important component of the high-pressure common rail fuel injection system, has the advantages of high control precision, strong adjustability, high energy efficiency and the like, and the fuel injection characteristic directly influences the economy and emission performance of the diesel engine.
In order to realize ultrahigh combustion and ultralow emission, the injection law curves of rectangular, slope-shaped, boot-shaped and the like are widely studied. The research shows that the boot-shaped oil injection rule with slow initial stage, rapid middle stage and rapid later stage can reduce the emission of nitrogen oxides, inhibit the mass generation of soot and the deterioration of thermal efficiency, and effectively reduce the emission of a diesel engine. However, the conventional electronic control fuel injector can only realize a rectangular fuel injection rule due to fixed structure, and meanwhile, the lift of a needle valve cannot be accurately controlled during low-flow injection, so that the fuel injection quantity is unstable, the fuel is wasted and the emission performance is reduced.
CN 115387944a discloses a low oil return variable needle valve opening rate electric control oil injector, the electromagnetic control valve component of the electric control oil injector comprises an outer control valve and an inner control valve, the oil return rate of a control cavity above the needle valve is determined by connecting different electric potentials through an electromagnetic valve, and the opening speed of the needle valve is changed, but the patent cannot accurately control the lift of the needle valve under small flow injection.
In order to improve the performance and efficiency of the diesel engine and meet the change of fuel requirements of the diesel engine under different working conditions, the electric control fuel injector adopts a more flexible and efficient fuel injection rule.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide the low-oil-return electric control oil sprayer with a flexible and adjustable oil spraying rule, which can reduce oil return quantity.
The invention aims at realizing the following technical scheme:
the low-oil return electric control oil sprayer with the changeable oil spraying rule sequentially comprises a fastening cap, an accumulation cavity, an electromagnetic valve body, an electromagnetic control valve assembly, a control valve body, a secondary control cavity, a primary control cavity and a needle valve injection assembly from top to bottom; the outer wall of the electric control fuel injector is limited and fixed through a fastening sleeve and a sleeve;
the fastening cap is matched with the pressure accumulation cavity to form a pressure accumulation cavity for placing high-pressure fuel; the fastening cap is axially provided with a high-pressure oil interface which is communicated with the pressure accumulation cavity; one end of a high-pressure oil way is communicated with the bottom of the pressure accumulation cavity, and the other end of the high-pressure oil way is communicated with the needle valve injection assembly;
the electromagnetic control valve assembly is positioned in the pressure accumulation cavity, the electromagnetic valve body and the control valve body;
The surface of the pressure accumulation cavity, which is abutted against the electromagnetic valve body, is internally provided with grooves to form a first cavity; the surface of the electromagnetic valve body facing the control valve body is inwards provided with a groove to form a second cavity; the surface of the secondary control cavity facing the primary control cavity is internally provided with a groove to form a fourth cavity;
the electromagnetic control valve assembly comprises an electromagnet, an armature, a limiting valve and a control valve from top to bottom in sequence; the needle valve injection assembly sequentially comprises a sliding block, a needle valve, a nozzle and spray holes from top to bottom; the outer wall of the control valve is propped against the inner wall of the control valve body to form cylindrical surface sealing, the outer wall of the needle valve is contacted with the inner wall of the primary control cavity to form cylindrical surface sealing, and a certain gap exists between the outer wall of the needle valve and the inner wall of the nozzle;
further, the electromagnet and the armature are arranged in the first cavity, the control valve reset spring penetrates through the electromagnet, the limit valve is positioned in the second cavity, and the limit valve reset spring is sleeved on the outer wall of the limit valve; the control valve is positioned in the control valve body and comprises an upward protruding cylinder and a flange which is positioned at the bottom layer and protrudes out of the upper layer cylinder along the circumferential direction, and the protruding cylinder passes through the limit valve and is in threaded connection with the armature; the control valve is in lower limit under the action of the elastic force of the control valve reset spring, and the limit valve is seated on the control valve body under the action of the elastic force of the limit valve reset spring;
The needle valve injection assembly sequentially comprises a sliding block, a needle valve, a nozzle and spray holes from top to bottom; the sliding block is positioned in the fourth cavity, and the outer wall of the sliding block is sleeved with a sliding block reset spring; the space formed by the inner wall of the fourth cavity and the sliding block is used as a secondary control cavity; the slider is seated on the primary control chamber by the combined action of hydraulic force and the spring force of the slider return spring. The bottom of the primary control cavity is connected with the top wall of the nozzle, and a plurality of spray holes are formed in the bottom of the nozzle;
the outer wall of the needle valve is contacted with the inner wall of the primary control cavity to form cylindrical surface sealing, and a certain gap exists between the outer wall of the needle valve and the inner wall of the nozzle; the needle valve reset spring is sleeved on the protrusion of the top of the needle valve; the space formed by the inner wall of the primary control cavity, the bottom wall of the sliding block and the needle valve is used as a primary control cavity; the needle valve is under the combined action of hydraulic pressure and the elastic force of the needle valve return spring and is seated on a valve seat processed by the nozzle;
a needle valve annular cavity is further arranged between the inner wall of the nozzle and the outer wall of the needle valve, and the needle valve annular cavity is communicated with a high-pressure oil path; a certain gap is formed between the lower end of the needle valve and the nozzle to form a pressure chamber, and the pressure chamber is communicated with the spray hole;
Along the circumferential direction of the control valve, 4 annular grooves are formed in the outer wall of the control valve, and each annular groove is matched with the inner wall of the control valve body to form a high-pressure cavity, a primary annular cavity, a secondary annular cavity and a low-pressure cavity respectively;
a low-pressure oil way is arranged in the control valve body, one end of the low-pressure oil way is communicated with the low-pressure cavity, and the other end of the low-pressure oil way is communicated with an external low-pressure oil tank; the control valve is internally provided with a control valve oil way, a high-pressure cavity bidirectional hole, a first-stage annular cavity bidirectional hole and a second-stage annular cavity bidirectional hole, and the control valve oil way is respectively communicated with the high-pressure cavity, the first-stage annular cavity and the second-stage annular cavity through the high-pressure cavity bidirectional hole, the first-stage annular cavity bidirectional hole and the second-stage annular cavity bidirectional hole; the control valve cavity is internally provided with a high-pressure cavity oil inlet orifice, a primary control cavity bidirectional orifice and a secondary control cavity bidirectional orifice in an inclined mode, one end of the high-pressure cavity oil inlet orifice is communicated with a high-pressure oil circuit, the other end of the high-pressure cavity oil inlet orifice is communicated with the high-pressure cavity, one end (namely an inlet) of the primary control cavity bidirectional orifice is communicated with the primary annular cavity, the other end of the primary control cavity bidirectional orifice is communicated with the primary control cavity after passing through the inside of the secondary control cavity, one end (namely the inlet) of the secondary control cavity bidirectional orifice is communicated with the secondary annular cavity, and the other end of the secondary control cavity is communicated with the secondary control cavity.
Wherein, the first-stage control fuel flow path: the low-pressure oil way is entered through a first-stage control cavity bidirectional orifice, a first-stage annular cavity bidirectional orifice, a control valve oil way and a gap between the control valve and a second-stage control cavity;
Secondary control fuel flow path: the two-way orifice of the secondary control cavity and the low pressure cavity enter a low pressure oil way;
needle valve injection assembly injection flow path: and the air enters the pressure chamber through the needle valve annular cavity and gaps among the outer wall of the needle valve and the inner wall of the nozzle.
The low oil return electric control oil sprayer has the following two injection modes when in rectangular oil injection regular injection:
small current fuel injection mode:
when a small current is introduced into the electromagnetic control valve assembly, the control valve is lifted to a limit position, the plane seal between the lower end of the control valve and the upper end surface of the secondary control cavity is opened, the needle valve of the needle valve injection assembly is lifted to the limit position, and high-pressure fuel flows through a primary control fuel flow path and a fuel injection flow path of the needle valve injection assembly;
high current fuel injection mode:
when a large current is introduced into the electromagnetic control valve assembly, the control valve drives the limit valve to lift to the upper limit position of the limit valve, the needle valve of the needle valve injection assembly drives the sliding block to lift to the upper limit position, and high-pressure fuel flows through the primary control fuel flow path, the secondary control fuel flow path and the fuel injection flow path of the needle valve injection assembly;
the low oil return electric control oil sprayer is characterized in that when the boot-shaped oil spraying rule is sprayed:
firstly, small current is introduced into an electromagnetic control valve assembly according to a small current fuel injection mode, and high-pressure fuel flows through a primary control fuel flow path and a fuel injection flow path of a needle valve injection assembly; and in the oil injection process, large current is introduced into the electromagnetic control valve assembly, the control valve drives the limit valve to lift to the upper limit position of the limit valve, the needle valve of the needle valve injection assembly drives the sliding block to lift to the upper limit position, and high-pressure fuel flows through the secondary control fuel flow path and the oil injection flow path of the needle valve injection assembly.
Furthermore, when the low-oil-return electric control oil injector sprays regularly in a rectangular oil injection mode, the low-oil-return electric control oil injector has the following two injection modes:
small current fuel injection mode:
when small current is introduced into the electromagnetic control valve assembly, the control valve is lifted to a limit position under the action of hydraulic force, electromagnetic force and elastic force, the control valve is not lifted any more, high-pressure fuel in the primary control cavity is controlled to flow through the primary control fuel flow path, then the needle valve of the needle valve injection assembly is controlled to be lifted to the limit position, the high-pressure fuel enters the pressure chamber through the fuel injection flow path of the needle valve injection assembly, and then is sprayed out from the spray hole to form a rectangular fuel injection rule curve;
high current fuel injection mode:
when a large current is introduced into the electromagnetic control valve assembly, the control valve is lifted to a limit position under the action of hydraulic force, electromagnetic force and elastic force and then drives the limit valve to continuously lift until reaching the upper limit position of the limit valve, high-pressure fuel in the primary control cavity is controlled to flow through the primary control fuel flow path and high-pressure fuel in the secondary control cavity flows through the secondary control fuel flow path, then the needle valve of the needle valve injection assembly is controlled to lift to the limit position, then the needle valve drives the sliding block to lift together until the sliding block reaches the upper limit position, the high-pressure fuel enters the pressure chamber through the fuel injection flow path of the needle valve injection assembly and is then sprayed out from the spray hole, and a rectangular fuel injection rule curve is formed;
The low oil return electric control oil sprayer is characterized in that when the boot-shaped oil spraying rule is sprayed:
firstly, small current is introduced into the electromagnetic control valve assembly according to a small current fuel injection mode, so that high-pressure fuel is sprayed out from a spray hole;
and in the oil injection process, large current is introduced into the electromagnetic control valve assembly, the control valve is lifted to a limit position under the action of hydraulic force, electromagnetic force and elastic force and then drives the limit valve to continuously lift until reaching the upper limit position of the limit valve, high-pressure fuel in the secondary control cavity is controlled to flow through a secondary control fuel flow path, the needle valve of the needle valve injection assembly is controlled to lift to the limit position, then the needle valve drives the sliding block to lift together until the sliding block reaches the upper limit position, and the high-pressure fuel enters the pressure chamber through the oil injection flow path of the needle valve injection assembly and is sprayed out from the spray hole.
Further, the limit position of the needle valve lifting is the lower end face of the sliding block; the limiting position of the lifting of the control valve is the lower end face of the limiting valve, and the upper limit position of the limiting valve is the top surface of the second cavity; the upper limit position of the sliding block is the top surface of the fourth cavity.
Further, the lower edge of the oil inlet orifice outlet of the high pressure cavity is flush with the lower edge of the high pressure cavity, the diameter of the oil inlet orifice outlet of the high pressure cavity is equal to the distance between the flange of the control valve and the lower end face of the limiting valve, the distance from the upper edge of the high pressure cavity to the lower edge of the high pressure cavity is larger than the diameter of the oil inlet orifice outlet of the high pressure cavity, and the diameter of the two-way hole of the high pressure cavity is equal to the distance from the upper edge of the high pressure cavity to the lower edge of the high pressure cavity.
Further, the upper edge of the two-way orifice inlet of the one-stage control cavity is flush with the upper edge of the one-stage annular cavity, the distance between the lower edge of the two-way orifice inlet of the one-stage control cavity and the lower edge of the one-stage annular cavity is larger than the maximum lift distance of the control valve, and the diameter of the two-way orifice inlet of the one-stage control cavity is equal to the distance between the flange of the control valve and the lower end face of the limit valve; the diameter of the two-way hole of the one-stage annular cavity is larger than that of the inlet of the two-way orifice of the one-stage control cavity, and the distance from the upper edge of the one-stage annular cavity to the lower edge of the high-pressure cavity is larger than the maximum lift distance of the control valve.
Further, the lower edge of the two-way orifice inlet of the secondary control cavity is flush with the lower edge of the secondary annular cavity, and the diameter of the two-way orifice inlet of the secondary control cavity is equal to the distance between the flange of the control valve and the lower end face of the limiting valve; the distance between the lower edge of the two-way orifice inlet of the secondary control cavity and the upper edge of the low-pressure cavity is equal to the distance between the flange of the control valve and the lower end surface of the limit valve; the distance from the upper edge of the secondary annular cavity to the lower edge of the secondary annular cavity is larger than the diameter of the inlet of the two-way orifice of the secondary control cavity, and the diameter of the two-way orifice of the secondary annular cavity is equal to the distance from the upper edge of the secondary annular cavity to the lower edge of the secondary annular cavity.
Further, the distance between the upper edge of the low-pressure cavity and the lower edge of the secondary annular cavity is equal to the distance between the flange of the control valve and the lower end face of the limiting valve, the distance between the lower end face of the electromagnet and the upper end face of the armature is greater than the maximum lift distance of the control valve, and the cross section area of the oil path of the control valve is greater than the sum of the cross section area of the inlet of the two-way throttle hole of the secondary control cavity and the cross section area of the inlet of the two-way throttle hole of the primary control cavity.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
1. the invention adopts the control cavity bidirectional oil way to supply oil and return oil to the control cavity, has simple structure, is easy to process and maintain, and after the electromagnetic control valve is electrified, the oil inlet orifice of the high-pressure cavity is disconnected with the high-pressure cavity, thereby reducing the oil return amount and improving the efficiency and the economy of the whole machine.
2. The electromagnetic control valve and the needle valve injection assembly are used for adjusting the needle valve lift to change the flow cross-sectional area inside the fuel injector, so that the fuel quantity injected into a cylinder in unit time of the fuel injector is changed, the flexible and variable fuel injection rule curve is realized, the requirements of different working conditions of the diesel engine are met, the combustion effect in the cylinder of the diesel engine is improved, and the pollutant emission is reduced.
Drawings
FIG. 1 is a schematic diagram of a low oil return electronically controlled fuel injector according to the present invention;
FIG. 2 is a schematic illustration of the configuration of the solenoid control valve assembly of FIG. 1;
FIG. 3 is a schematic illustration of the needle injection assembly of FIG. 1;
FIG. 4 is a cross-sectional view of the low return electric control fuel injector without the solenoid control valve assembly and the needle injection assembly shown.
In the figure:
1: a high-pressure oil interface; 2: a fastening cap; 3: a pressure accumulation cavity; 4: an electromagnetic valve body; 5: a solenoid control valve assembly; 6: a control valve body; 7: a secondary control cavity; 8: a needle valve injection assembly; 9: a pressure accumulation cavity; 10: a fastening sleeve; 11: a high-pressure oil path; 12: a sleeve; 13: a primary control cavity; 101: a first cavity; 102: a second cavity; 103: a third cavity; 104: a fourth cavity; 105: a fifth cavity; 106: a sixth cavity; 501: an electromagnet; 502: an armature; 503: a limit valve; 504: a control valve; 505: a high pressure chamber; 506: a first-stage annular cavity bidirectional hole; 507: a first-stage control chamber bidirectional orifice; 508: a two-way hole of the secondary annular cavity; 509: two-way orifice of the second-stage control cavity; 510: a low pressure chamber; 511: a control valve return spring; 512: a limit valve return spring; 513: a high pressure chamber bi-directional orifice; 514: an oil inlet orifice of the high-pressure cavity; 515: a primary annular cavity; 516: controlling an oil way of the valve; 517: a secondary annular cavity; 518: a low-pressure oil path; 801: a secondary control chamber; 802: a primary control chamber; 803: a needle valve; 804: a nozzle; 805: a needle valve annulus; 806: a spray hole; 807: a slider return spring; 808: a slide block; 809: needle valve return spring; 810: a pressure chamber.
Detailed Description
In order to make the objects, technical solutions, advantageous effects and significant improvements of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings provided in the examples of the present application, and it is apparent that all of the described embodiments are only some embodiments of the present application, not all embodiments; all other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the description of the present application, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance unless explicitly specified or limited otherwise; the term "plurality" refers to two or more than two; unless specified or indicated otherwise, the terms "coupled," "fixed," and the like are to be construed broadly and are, for example, capable of being coupled either permanently or detachably, or integrally or electrically; "coupled" may be directly coupled or indirectly coupled through intermediaries. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
As shown in fig. 1, the low-oil return electric control oil injector with a variable oil injection rule sequentially comprises a fastening cap 2, an accumulation cavity 3, an electromagnetic valve body 4, an electromagnetic control valve assembly 5, a control valve body 6, a secondary control cavity 7, a primary control cavity 13 and a needle valve injection assembly 8 from top to bottom.
The fastening cap 2 is tightly matched and buckled on the top end of the pressure accumulation cavity 3 and the outer wall positioned at the upper part, the inner wall of the fastening cap 2 is in threaded connection with the outer surface of the upper part of the pressure accumulation cavity 3, and a sealing gasket is arranged between the contact surfaces of the fastening cap 2 and the pressure accumulation cavity 3 for increasing the tightness; the pressure accumulation cavity 3 is provided with a hollow cylindrical space, and the fastening cap 2 is matched with the pressure accumulation cavity 3 to form a pressure accumulation cavity 9. The fastening cap 2 is axially provided with a high-pressure oil port 1, and the high-pressure oil port 1 is communicated with the pressure accumulation cavity 9. The high-pressure oil way 11 is arranged in the pressure accumulation cavity 3, one end of the high-pressure oil way 11 is positioned at the bottom of the pressure accumulation cavity 9 and is communicated with the pressure accumulation cavity 9, and the high-pressure oil way 11 sequentially passes through the electromagnetic valve body 4, the control valve body 6, the secondary control cavity 7, the primary control cavity 13 and the nozzle 804 and then reaches the needle valve annular cavity 805. A fastening sleeve 10 is tightly matched and wrapped on part of the outer wall of the pressure accumulation cavity 3, the outer wall of the electromagnetic valve body 4 and part of the outer wall of the control valve body 6, and a sleeve 12 is tightly matched and wrapped on part of the outer wall of the control valve body 6, the outer wall of the secondary control cavity 7, the outer wall of the primary control cavity 13 and the outer wall of the needle valve injection assembly 8.
As shown in fig. 4, the surface of the pressure accumulating cavity 3 abutting against the electromagnetic valve body 4 is respectively provided with a groove inwards, so that a first cavity 101 is formed inside the pressure accumulating cavity 3 and the electromagnetic valve body 4. The electromagnetic valve body 4 is provided with a groove inwards on the surface abutting against the control valve body 6 to form a second cavity 102, and the control valve body 6 is penetrated through a through hole along the central axis to form a third cavity 103 (penetrated through the control valve body 6). The surface of the secondary control cavity 7 abutting against the primary control cavity 13 is internally provided with a groove to form a fourth cavity 104, the primary control cavity 13 penetrates through a through hole along the central axis direction of the primary control cavity as a fifth cavity 105, and the nozzle 804 of the needle valve injection assembly 8 is provided with a funnel-shaped groove along the central axis direction of the nozzle 804 as a sixth cavity 106. Wherein the first cavity and the second cavity are communicated through the through hole, the second cavity and the third cavity are communicated, and the fourth cavity and the fifth cavity are communicated, wherein the diameter of the second cavity is larger than that of the third cavity, so that the limit valve 503 is seated on the upper surface of the control valve body 6.
The electromagnetic control valve assembly 5 (see upper ring middle part in fig. 1) is vertically arranged inside the pressure accumulation cavity 3, the electromagnetic valve body 4 and the control valve body 6 along the central axis of the low oil return electric control injector, as shown in fig. 2, the electromagnetic control valve assembly comprises an electromagnet 501, an armature 502, a limiting valve 503 and a control valve 504 from top to bottom, and a limiting valve return spring 512 and a control valve return spring 511 are centrally arranged inside the electromagnetic control valve assembly 5. The control valve 504 is located in the third cavity, the outer wall of the control valve 504 abuts against the inner wall of the third cavity (i.e. the inner wall of the control valve body 6) to form a cylindrical seal, and the lower end surface of the control valve 504 is in close contact with the upper end surface of the secondary control cavity 7 to form a planar seal to block the communication between the control valve oil path 516 and the low pressure oil path 518.
The electromagnet 501 and the armature 502 are arranged in the first cavity, wherein the outer surface of the electromagnet 501 abuts against a groove formed at the bottom of the pressure accumulation cavity 3, and the armature 502 is positioned in the groove formed by the electromagnetic valve body 4. And the electromagnet 501 penetrates a cylindrical cavity along the central direction thereof for placing the control valve return spring 511. One end of the control valve return spring 511 is propped against the bottom of the pressure accumulation cavity 3, and the other end is propped against the upper surface of the armature 502.
The limiting valve 503 is located in the second cavity, the limiting valve 503 and the armature 502 are both provided with through holes penetrating along the central direction of the limiting valve and the armature 502, and the inner wall of each through hole of the armature 502 is provided with threads. The control valve 504 is of a two-layer boss structure, and comprises an upward protruding cylinder and a flange located at the bottom layer and protruding out of the upper cylinder along the circumferential direction, the upper surface of the flange is opposite to the lower end surface of the limit valve 503, the cylinder with the top protruding upward passes through the through hole of the limit valve 503 and is in threaded connection with the through hole of the armature 502, and the control valve 504 is in lower limit under the action of the elastic force of the control valve return spring 511. The size of the through holes of the limiting valve 503 and the armature 502 are matched with the size of the cylinder of the control valve 504 protruding upwards.
The limiting valve 503 is of a two-layer boss structure, the outer wall of the boss at the uppermost layer is sleeved with a limiting valve reset spring 512, the lower end of the limiting valve reset spring 512 is propped against the boss at the lower layer of the limiting valve 503, the upper end of the limiting valve is propped against the top wall of the second cavity, and the lower end face of the limiting valve 503 reaches the upper end face of the control valve body 6, so that the limiting valve is seated on the control valve body 6 under the action of the elastic force of the limiting valve reset spring 512.
As shown in fig. 3, the needle injection assembly 8 includes a slider 808, a needle 803, a nozzle 804, and an injection hole 806 from top to bottom. The sliding block 808 is positioned in the fourth cavity, the outer wall of the sliding block 808 is sleeved with a sliding block return spring 807, the lower end of the sliding block return spring 807 is propped against a lower boss of the sliding block 808, and the upper end is propped against the top wall of the fourth cavity; a space formed by the inner wall of the fourth cavity and the sliding block 808 is used as a secondary control cavity 801; the lower end of the slider 808 abuts against the upper end surface of the primary control chamber 13, so that the slider 808 is seated on the primary control chamber 13 under the combined action of hydraulic force and the elastic force of the slider return spring 807. The bottom of the primary control cavity 13 is connected to the top wall of the nozzle 804, and a plurality of spray holes 806 are formed in the bottom of the nozzle 804. The needle 803 sequentially penetrates through the fifth cavity and the sixth cavity, the outer wall of the needle 803 contacts with the inner wall of the fifth cavity (i.e., with the inner wall of the secondary control cavity 7) to form cylindrical surface sealing, and a certain gap is reserved between the outer wall of the needle 803 and the inner wall of the nozzle 804 for circulating liquid. The top of the needle 803 is provided with a columnar bulge, the outer surface of the columnar bulge is sleeved with a needle return spring 809, the lower end of the needle return spring 809 is propped against the top of the needle 803, and the other end of the needle return spring is propped against a platform of the primary control cavity 13 extending from the top end of the primary control cavity to the central shaft direction. The space formed by the inner wall of the primary control chamber 13, the bottom wall of the slider 808 and the needle 803 is used as the primary control chamber 802. The needle 803 is seated on a valve seat formed in the nozzle 804 by a combination of hydraulic force and elastic force of a needle return spring 809.
In the sixth cavity, an annular cavity is further disposed between the inner wall of the nozzle 804 and the outer wall of the needle 803, and the needle valve cavity 805 is used as a needle valve cavity 805, and the needle valve cavity 805 is communicated with the high-pressure oil channel 11. A certain gap is formed between the lower end of the needle valve 803 and the nozzle 804 to form a pressure chamber 810, and the pressure chamber 810 is communicated with the spray hole 806.
During installation, the pressure accumulation cavity 3, the electromagnetic valve body 4, the control valve body 6, the secondary control cavity 7, the primary control cavity 13 and the nozzle 804 are installed from top to bottom, and are limited and fixed through the fastening sleeve 10 and the sleeve 12.
Along the circumferential direction of the control valve 504, 4 annular grooves are formed on the outer wall of the control valve 504, and each annular groove is matched with the inner wall of the control valve body 6 to form a high-pressure cavity 505, a primary annular cavity 515, a secondary annular cavity 517 and a low-pressure cavity 510 respectively. A low-pressure oil way 518 is arranged in the control valve body 6, one end of the low-pressure oil way 518 is communicated with the low-pressure cavity 510, and the other end of the low-pressure oil way 518 is communicated with an external low-pressure oil tank; the control valve 504 is internally provided with a control valve oil path 516, a high-pressure cavity bidirectional hole 513, a primary annular cavity bidirectional hole 506 and a secondary annular cavity bidirectional hole 508, and the control valve oil path 516 is respectively communicated with the high-pressure cavity 505, the primary annular cavity 515 and the secondary annular cavity 517 through the high-pressure cavity bidirectional hole 513, the primary annular cavity bidirectional hole 506 and the secondary annular cavity bidirectional hole 508. The control valve 504 is also obliquely provided with a high-pressure cavity oil inlet orifice 514, a primary control cavity bidirectional orifice 507 and a secondary control cavity bidirectional orifice 509, one end of the high-pressure cavity oil inlet orifice 514 is communicated with the high-pressure oil channel 11, the other end of the high-pressure cavity oil inlet orifice is communicated with the high-pressure cavity 505, the lower edge of the outlet of the high-pressure cavity oil inlet orifice 514 is flush with the lower edge of the high-pressure cavity 505, the diameter of the outlet of the high-pressure cavity oil inlet orifice 514 is equal to the distance between the flange of the control valve 504 and the lower end face of the limit valve 503, the distance from the upper edge of the high-pressure cavity 505 to the lower edge of the high-pressure cavity 505 is greater than the diameter of the outlet of the high-pressure cavity oil inlet orifice 514, and the diameter of the high-pressure cavity bidirectional orifice 513 is equal to the distance from the upper edge of the high-pressure cavity 505 to the lower edge of the high-pressure cavity 505; one end (i.e. an inlet) of the one-stage control cavity bidirectional orifice 507 is communicated with the one-stage annular cavity 515, the other end is communicated with the one-stage control cavity 802 through the inside of the two-stage control cavity 7, the upper edge of the inlet of the one-stage control cavity bidirectional orifice 507 is flush with the upper edge of the one-stage annular cavity 515, the distance between the lower edge of the inlet of the one-stage control cavity bidirectional orifice 507 and the lower edge of the one-stage annular cavity 515 is larger than the maximum lift distance of the control valve 504, and the diameter of the inlet of the one-stage control cavity bidirectional orifice 507 is equal to the distance between the flange of the control valve 504 and the lower end face of the limit valve 503; the diameter of the one-step annular cavity bi-directional orifice 506 is greater than the diameter of the inlet of the one-step control cavity bi-directional orifice 507, and the distance from the upper edge of the one-step annular cavity 515 to the lower edge of the high pressure cavity 505 is greater than the maximum lift distance of the control valve 504. One end (i.e., inlet) of the two-way orifice 509 of the secondary control chamber is connected to the secondary annular chamber 517, and the other end is connected to the secondary control chamber 801. The lower edge of the inlet of the two-way orifice 509 of the secondary control cavity is flush with the lower edge of the secondary annular cavity 517, and the diameter of the inlet of the two-way orifice 509 of the secondary control cavity is equal to the distance between the flange of the control valve 504 and the lower end face of the limit valve 503; the distance between the lower edge of the inlet of the two-way orifice 509 of the secondary control chamber and the upper edge of the low-pressure chamber 510 is equal to the distance between the flange of the control valve 504 and the lower end surface of the limit valve 503; the distance from the upper edge of the secondary ring chamber 517 to the lower edge of the secondary ring chamber 517 is greater than the diameter of the inlet of the secondary control chamber bi-directional orifice 509, and the diameter of the secondary ring chamber bi-directional orifice 508 is equal to the distance from the upper edge of the secondary ring chamber 517 to the lower edge of the secondary ring chamber 517.
The distance from the upper edge of the low-pressure chamber 510 to the lower edge of the secondary annular chamber 517 is equal to the distance between the flange of the control valve 504 and the lower end surface of the limiting valve 503, the distance between the lower end surface of the electromagnet 501 and the upper end surface of the armature 502 is greater than the maximum lift distance of the control valve 504, and the cross-sectional area of the control valve oil path 516 is greater than the sum of the cross-sectional area of the inlets of the secondary control chamber bi-directional orifice 509 and the primary control chamber bi-directional orifice 507.
The low-oil-return electric control fuel injector can realize fuel injection modes of two fuel injection regular curve shapes of rectangular and shoe shapes. When rectangular injection is carried out, the injection is divided into two cases, wherein one case is that the electromagnetic control valve assembly 5 is electrified with small current, and the other case is that the electromagnetic control valve assembly 5 is electrified with large current. When the boot-shaped oil injection regular injection is carried out, small current is firstly conducted to the electromagnetic control valve assembly 5, and then large current is conducted to the electromagnetic control valve assembly 5.
Fuel injection mode of rectangular fuel injection rule curve with small current:
when a small current is introduced into the electromagnetic control valve assembly 5, the sum of the electromagnetic force received by the armature 502 and the hydraulic force received by the control valve 504 is larger than the elastic force of the control valve return spring 511 positioned on the upper surface of the armature and smaller than the sum of the elastic force of the control valve return spring 511 and the elastic force of the limit valve return spring 512, the control valve 504 is lifted upwards under the combined action of the hydraulic force, the electromagnetic force of the armature 502 and the elastic force of the control valve return spring 511 until the flange of the control valve 504 reaches the lower end face of the limit valve 503, the control valve 504 is not lifted any more, the plane seal between the lower end of the control valve 504 and the upper end face of the secondary control cavity 7 is opened, at the moment, the control valve 504 moves upwards, so that the high-pressure cavity oil inlet orifice 514 is staggered with the high-pressure cavity 505, the side wall of the control valve 504 and the control valve 6 form cylindrical seal, and high-pressure fuel is prevented from entering the control valve oil way 516 through the high-pressure cavity 505 and the high-pressure cavity bidirectional orifice 513; the high-pressure fuel in the primary control cavity 802 enters the low-pressure fuel passage 518 through the primary control cavity bidirectional throttle hole 507, the primary annular cavity 515, the primary annular cavity bidirectional hole 506, the control valve fuel passage 516, and the gap between the control valve 504 and the secondary control cavity 7; at this time, the pressure of the fuel in the primary control chamber 802 is continuously reduced until the hydraulic pressure at the lower end of the needle 803 is greater than the sum of the hydraulic pressure at the upper end of the needle 803 and the elastic force of the needle return spring 809, and the needle 803 starts to lift up until the upper end of the needle 803 reaches the lower end of the slider 808, i.e., the needle 803 is limited to the lower end face of the slider and does not rise any more, and the high-pressure fuel enters the pressure chamber 810 through the needle valve ring cavity 805, the gap between the outer wall of the needle 803 and the inner wall of the nozzle 804, and is then ejected from the nozzle hole 806.
Fuel injection mode of rectangular fuel injection rule curve with large current:
when a large current is introduced into the electromagnetic control valve assembly 5, the sum of the electromagnetic force received by the armature 502 and the hydraulic force received by the control valve 504 is larger than the sum of the elastic force of the control valve return spring 511 and the elastic force of the limit valve return spring 512, the control valve 504 is lifted upwards under the combined action of the hydraulic force, the electromagnetic force of the armature 502 and the elastic force of the control valve return spring 511, the flange of the control valve 504 contacts with the lower end of the limit valve 503 and then drives the limit valve 503 to lift up together until the limit valve 503 reaches the upper limit position (i.e. the upper end surface of the limit valve 503 reaches the top surface of the second cavity), the control valve 504 and the limit valve 503 are not lifted up any more, the plane seal between the lower end of the control valve 504 and the upper end surface of the second-stage control cavity 7 is opened, at this time, the control valve 504 moves upwards, the high-pressure cavity oil inlet orifice 514 is staggered with the high-pressure cavity 505, and the side wall of the control valve 504 forms a cylindrical seal with the control valve 6, the high-pressure fuel in the first-stage control chamber 802 enters the low-pressure oil path 518 through the first-stage control chamber bi-directional orifice 507, the first-stage annular chamber 515, the first-stage annular chamber bi-directional orifice 506, the control valve oil path 516, the gap between the control valve 504 and the second-stage control chamber 7, the high-pressure fuel in the second-stage control chamber 801 enters the low-pressure oil path 518 through the second-stage control chamber bi-directional orifice 509 and the low-pressure chamber 510, the internal-pressure fuel in the first-stage control chamber 802 and the second-stage control chamber 801 continuously decreases until the hydraulic pressure at the lower end of the needle 803 is greater than the sum of the hydraulic pressure at the upper end of the needle 803 and the elastic force of the needle return spring 809, the needle 803 starts to lift until the upper end of the needle 803 reaches the lower end of the slider 808, the needle 803 stops to lift until the sum of the hydraulic pressure at the lower end of the needle 803 and the lower end of the slider 808 is greater than the hydraulic pressure at the upper end of the slider 808, the hydraulic pressure at the upper end of the needle return spring 809 and the sum of the elastic force of the slider return spring 807, the needle 803 drives the slider 808 to rise together until the slider 808 reaches its upper limit (i.e., the upper end surface of the slider 808 contacts the top surface of the fourth cavity), the needle 803 and the slider 808 no longer rise, and high-pressure fuel enters the pressure chamber 810 through the needle valve annular cavity 805 and the gap between the needle 803 and the nozzle 804, and is ejected from the nozzle 806.
Fuel injection mode of boot-shaped fuel injection law curve:
firstly, small current is introduced into the electromagnetic control valve assembly 5, the sum of electromagnetic force received by the armature 502 and hydraulic force received by the control valve 504 is larger than the elastic force of the control valve return spring 511 and smaller than the sum of the elastic force of the control valve return spring 511 and the elastic force of the limiting valve return spring 512, the control valve 504 is lifted upwards under the combined action of the hydraulic force, the electromagnetic force of the armature 502 and the elastic force of the control valve return spring 511 until the upper surface of a flange of the control valve 504 is contacted with the lower end of the limiting valve 503, the control valve 504 is not lifted any more, the plane seal between the lower end of the control valve 504 and the upper end face of the secondary control cavity 7 is opened, meanwhile, the side wall of the control valve 504 and the control valve 6 form cylindrical seal, the oil inlet orifice 514 of the high-pressure cavity is staggered with the high-pressure cavity 505, the side wall of the control valve 504 and the control valve 6 form cylindrical seal, high-pressure fuel is prevented from entering the control valve oil path 516 through the high-pressure cavity 505 and the high-pressure cavity bidirectional hole 513, high-pressure fuel in the primary control cavity 802 enters the low-pressure oil path 518 through the primary control cavity bidirectional orifice 507, the primary annular cavity 515, the primary annular cavity bidirectional hole 506, the control valve oil path 516 and a gap between the control valve 504 and the secondary control cavity 7, the internal-combustion fuel pressure in the primary control cavity 802 is continuously reduced until the hydraulic pressure at the lower end of the needle 803 is larger than the sum of the hydraulic pressure at the upper end of the needle 803 and the elastic force of the needle return spring 809, the needle 803 starts to lift up until the upper end of the needle 803 reaches the lower end of the slider 808, the needle 803 does not lift up any more, and the high-pressure fuel enters the pressure chamber 810 through the needle annular cavity 805, the gap between the needle 803 and the nozzle 804 and is sprayed out from the spray hole 806;
As the injection process proceeds, a large current is fed to the solenoid control valve assembly 5, the sum of the electromagnetic force of the armature 502 and the hydraulic force received by the control valve 504 is greater than the sum of the elastic force of the control valve return spring 511 and the elastic force of the limit valve return spring 512, the control valve 504 drives the limit valve 503 to rise together until the limit valve 503 reaches the upper limit position, both the control valve 504 and the limit valve 503 are not raised together, at this time, the seal at the inlet of the two-way orifice 509 of the secondary control chamber (i.e. the end communicating with the two-way annular chamber 517) opens along with the rise of the control valve 504, the high-pressure fuel in the two-way control chamber 801 enters the low-pressure oil path 518 through the two-way orifice 509 of the secondary control chamber and the low-pressure chamber 510, the hydraulic pressure in the two-way control chamber 801 is continuously reduced until the sum of the hydraulic force at the lower end of the needle 803 and the hydraulic force at the lower end of the slider 808 is greater than the hydraulic force at the upper end 803, the needle valve 808 is raised together with the sum of the elastic force of the needle valve return spring 809 and the slider return spring 807, and the needle 808 is driven by the slider 808 to rise together until the slider 808 reaches the upper limit position, both the needle 803 and the slider 808 is not raised again, and the high-pressure fuel is ejected from the slider 803.
After the injection mode is finished, the electromagnetic control valve assembly 5 stops being electrified, the limiting valve 503 is seated on the control valve body 6 under the action of the elastic force of the limiting valve return spring 512 (namely, the lower end of the limiting valve 503 reaches the upper end face of the control valve body 6), the control valve 504 is seated on the second-stage control cavity 7 under the combined action of the hydraulic force and the elastic force of the control valve return spring 511, the high-pressure cavity oil inlet orifice 514 is connected with the high-pressure cavity 505, the first-stage control cavity bidirectional orifice 507 is connected with the first-stage annular cavity 515, the second-stage control cavity bidirectional orifice 509 is connected with the second-stage annular cavity 517, the lower end of the control valve 504 and the upper end face of the second-stage control cavity 7 form a plane seal to block the communication between the control valve oil path 516 and the low-pressure oil path 518, high-pressure oil in the pressure accumulating cavity 9 enters the control valve oil path 516 through the high-pressure oil path 11, the high-pressure cavity oil inlet orifice 514, the high-pressure cavity 505 and the high-pressure cavity bidirectional orifice 513, the high-pressure fuel in the control valve oil path 516 supplements the high-pressure fuel in the first-stage control cavity 802 through the first-stage annular cavity bidirectional hole 506, the first-stage annular cavity 515 and the first-stage control cavity bidirectional orifice 507, supplements the high-pressure fuel in the second-stage control cavity 801 through the second-stage annular cavity bidirectional hole 508, the second-stage annular cavity 517 and the second-stage control cavity bidirectional orifice 509, improves the internal combustion oil pressure of the first-stage control cavity 802 and the second-stage control cavity 801, the sliding block 808 is seated on the first-stage control cavity 13 under the combined action of hydraulic pressure and the elastic force of the sliding block return spring 807, the needle valve 803 is seated on a valve seat machined by the nozzle 804 under the combined action of the hydraulic pressure and the elastic force of the needle valve return spring 809, and the oil injection is ended.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail herein, but rather is provided for the purpose of enabling those skilled in the art to make and use the embodiments described herein.

Claims (6)

1. The low-oil return electric control oil sprayer with the changeable oil spraying rule is characterized by sequentially comprising a fastening cap (2), an accumulation cavity (3), an electromagnetic valve body (4), an electromagnetic control valve assembly (5), a control valve body (6), a secondary control cavity (7), a primary control cavity (13) and a needle valve injection assembly (8) from top to bottom; the outer wall of the electric control fuel injector is limited and fixed through a fastening sleeve (10) and a sleeve (12);
the fastening cap (2) is matched with the pressure accumulation cavity (3) to form a pressure accumulation cavity (9) for placing high-pressure fuel; the fastening cap (2) is axially provided with a high-pressure oil interface (1), and the high-pressure oil interface is communicated with the pressure accumulation cavity (9); one end of the high-pressure oil channel (11) is communicated with the bottom of the pressure accumulation cavity (9), and the other end is communicated with the needle valve injection assembly (8);
The electromagnetic control valve assembly (5) is positioned in the pressure accumulation cavity (3), the electromagnetic valve body (4) and the control valve body (6);
the surface of the pressure accumulation cavity (3) which is abutted against the electromagnetic valve body (4) is internally provided with grooves to form a first cavity (101); a groove is formed in the surface of the electromagnetic valve body (4) facing the control valve body (6) inwards to form a second cavity (102); a groove is formed in the surface, facing the primary control cavity (13), of the secondary control cavity (7) inwards to form a fourth cavity (104);
the electromagnetic control valve assembly (5) comprises an electromagnet (501), an armature (502), a limit valve (503) and a control valve (504) from top to bottom in sequence; the needle valve injection assembly (8) comprises a sliding block (808), a needle valve (803), a nozzle (804) and a spray hole (806) from top to bottom in sequence; the outer wall of the control valve (504) is propped against the inner wall of the control valve body (6) to form cylindrical surface sealing, the outer wall of the needle valve (803) is contacted with the inner wall of the primary control cavity (13) to form cylindrical surface sealing, and a certain gap exists between the outer wall of the needle valve (803) and the inner wall of the nozzle (804);
the electromagnet (501) and the armature (502) in the electromagnetic control valve assembly (5) are arranged in the first cavity (101), the control valve return spring (511) penetrates through the electromagnet (501), the limit valve (503) is positioned in the second cavity (102), and the outer wall of the limit valve return spring is sleeved with the limit valve return spring (512); the control valve (504) is positioned in the control valve body (6) and comprises an upward protruding cylinder and a flange which is positioned at the bottom layer and protrudes out of the upper layer cylinder along the circumferential direction, and the protruding cylinder passes through the limit valve (503) and is in threaded connection with the armature (502); the control valve (504) is in lower limit under the action of the elastic force of the control valve return spring (511), and the limit valve (503) is seated on the control valve body (6) under the action of the elastic force of the limit valve return spring (512);
The sliding block (808) of the needle valve injection assembly (8) is positioned in the fourth cavity, and the outer wall of the sliding block is sleeved with a sliding block return spring (807); a space formed by the inner wall of the fourth cavity and the sliding block (808) is used as a secondary control cavity (801); the sliding block (808) is under the combined action of hydraulic force and the elastic force of the sliding block return spring (807) to be seated on the primary control cavity (13); the bottom of the primary control cavity (13) is connected with the top wall of the nozzle (804), and a plurality of spray holes (806) are formed in the bottom of the nozzle (804);
the needle valve reset spring (809) is sleeved on the top of the needle valve (803) and protrudes; a space formed by the inner wall of the primary control cavity (13), the bottom wall of the sliding block (808) and the needle valve (803) is used as a primary control cavity (802); the needle valve (803) is seated on a valve seat machined by the nozzle (804) under the combined action of hydraulic force and elastic force of a needle valve return spring (809);
a needle valve annular cavity (805) is further arranged between the inner wall of the nozzle (804) and the outer wall of the needle valve (803), and the needle valve annular cavity (805) is communicated with the high-pressure oil channel (11); a certain gap is formed between the lower end of the needle valve (803) and the nozzle (804), a pressure chamber (810) is formed, and the pressure chamber (810) is communicated with the spray hole (806);
Along the circumferential direction of the control valve (504), 4 annular grooves are formed in the outer wall of the control valve (504), and each annular groove is matched with the inner wall of the control valve body (6) to form a high-pressure cavity (505), a primary annular cavity (515), a secondary annular cavity (517) and a low-pressure cavity (510) respectively;
a low-pressure oil way (518) is arranged in the control valve body (6), one end of the low-pressure oil way (518) is communicated with the low-pressure cavity (510), and the other end is communicated with an external low-pressure oil tank; a control valve oil circuit (516), a high-pressure cavity bidirectional hole (513), a primary annular cavity bidirectional hole (506) and a secondary annular cavity bidirectional hole (508) are arranged in the control valve (504), and the control valve oil circuit (516) is respectively communicated with the high-pressure cavity (505), the primary annular cavity (515) and the secondary annular cavity (517) through the high-pressure cavity bidirectional hole (513), the primary annular cavity bidirectional hole (506) and the secondary annular cavity bidirectional hole (508); the control valve (504) is internally provided with a high-pressure cavity oil inlet orifice (514), a first-stage control cavity bidirectional orifice (507) and a second-stage control cavity bidirectional orifice (509) in a tilting manner, one end of the high-pressure cavity oil inlet orifice (514) is communicated with the high-pressure oil channel (11), the other end of the high-pressure cavity oil inlet orifice is communicated with the high-pressure cavity (505), an inlet of the first-stage control cavity bidirectional orifice (507) is communicated with the first-stage annular cavity (515), the other end of the first-stage control cavity is communicated with the first-stage control cavity (802) after passing through the inside of the second-stage control cavity (7), an inlet of the second-stage control cavity bidirectional orifice (509) is communicated with the second-stage annular cavity (517), and the other end of the second-stage control cavity (801);
The primary control fuel flow path is as follows: the low-pressure oil path (518) enters through a first-stage control cavity bidirectional orifice (507), a first-stage annular cavity (515), a first-stage annular cavity bidirectional hole (506), a control valve oil path (516), a gap between a control valve (504) and a second-stage control cavity (7);
secondary control fuel flow path: enter the low-pressure oil circuit (518) through the two-way orifice (509) of the second-stage control chamber and the low-pressure chamber (510);
needle valve injection assembly injection flow path: enters a pressure chamber (810) through a gap between a needle valve annular cavity (805), the outer wall of the needle valve (803) and the inner wall of the nozzle (804), and is then ejected from the spray hole (806);
the low oil return electric control oil sprayer has the following two injection modes when in rectangular oil injection regular injection:
small current fuel injection mode:
when small current is introduced into the electromagnetic control valve assembly (5), the control valve (504) is lifted to a limit position under the action of hydraulic force, electromagnetic force and elastic force, the control valve (504) is not lifted any more, high-pressure fuel in the primary control cavity is controlled to flow through the primary control fuel flow path, then the needle valve (803) of the needle valve injection assembly (8) is controlled to be lifted to the limit position, the high-pressure fuel enters the pressure chamber through the fuel injection flow path of the needle valve injection assembly, and then the high-pressure fuel is sprayed out from the spray hole to form a rectangular fuel injection rule curve;
High current fuel injection mode:
when a large current is introduced into the electromagnetic control valve assembly (5), the control valve (504) is lifted to a limit position under the action of hydraulic force, electromagnetic force and elastic force, then the limit valve (503) is driven to be lifted to the upper limit position of the limit valve (503), high-pressure fuel in the primary control cavity is controlled to flow through the primary control fuel flow path and high-pressure fuel in the secondary control cavity flows through the secondary control fuel flow path, then a needle valve (803) of the needle valve injection assembly (8) is controlled to be lifted to the limit position, and then the needle valve drives a sliding block (808) to lift together until the sliding block reaches the upper limit position, the high-pressure fuel enters a pressure chamber through the fuel injection flow path of the needle valve injection assembly, and is sprayed out from a spray orifice to form a rectangular fuel injection rule curve;
the low oil return electric control oil sprayer is characterized in that when the boot-shaped oil spraying rule is sprayed:
firstly, small current is introduced into an electromagnetic control valve assembly (5) according to a small current fuel injection mode, and high-pressure fuel flows through a primary control fuel flow path and a fuel injection flow path of a needle valve injection assembly and is sprayed out from a spray hole; in the oil injection process, large current is introduced into the electromagnetic control valve assembly (5), the control valve (504) is lifted to the limit position under the action of hydraulic force, electromagnetic force and elastic force, then the limit valve (503) is driven to continuously ascend until reaching the upper limit position of the limit valve (503), high-pressure fuel in the secondary control cavity is controlled to flow through the secondary control fuel flow path, the needle valve of the needle valve injection assembly (8) is controlled to be lifted to the limit position, then the needle valve (803) drives the sliding block to ascend together until the sliding block (808) reaches the upper limit position, and the high-pressure fuel enters the pressure chamber through the oil injection flow path of the needle valve injection assembly and is sprayed out from the spray hole.
2. The low-oil return electric control fuel injector with a variable fuel injection rule according to claim 1, wherein the limit position of the lifting of the needle valve (803) is the lower end face of the sliding block (808); the limit position of the lifting of the control valve (504) is the lower end face of the limit valve (503), and the upper limit position of the limit valve (503) is the top face of the second cavity; the upper limit position of the sliding block (808) is the top surface of the fourth cavity.
3. The low oil return electric control fuel injector with variable fuel injection rules according to claim 1, wherein the lower edge of the outlet of the high pressure cavity oil inlet orifice (514) is flush with the lower edge of the high pressure cavity (505), the outlet diameter of the high pressure cavity oil inlet orifice (514) is equal to the distance between the flange of the control valve (504) and the lower end face of the limit valve (503), the distance from the upper edge of the high pressure cavity (505) to the lower edge of the high pressure cavity (505) is greater than the outlet diameter of the high pressure cavity oil inlet orifice (514), and the diameter of the high pressure cavity bidirectional hole (513) is equal to the distance from the upper edge of the high pressure cavity (505) to the lower edge of the high pressure cavity (505).
4. The low oil return electric control fuel injector with a variable fuel injection rule according to claim 1, wherein the upper edge of the inlet of the one-stage control cavity bidirectional orifice (507) is flush with the upper edge of the one-stage annular cavity (515), the distance from the lower edge of the inlet of the one-stage control cavity bidirectional orifice (507) to the lower edge of the one-stage annular cavity (515) is larger than the maximum lift distance of the control valve (504), and the diameter of the inlet of the one-stage control cavity bidirectional orifice (507) is equal to the distance between the flange of the control valve (504) and the lower end face of the limit valve (503); the diameter of the one-stage annular cavity bidirectional hole (506) is larger than the inlet diameter of the one-stage control cavity bidirectional orifice (507), and the distance from the upper edge of the one-stage annular cavity (515) to the lower edge of the high-pressure cavity (505) is larger than the maximum lift distance of the control valve (504).
5. The low oil return electric control fuel injector with variable fuel injection rules according to claim 1, wherein the lower edge of the inlet of the two-way throttle hole (509) of the secondary control cavity is flush with the lower edge of the two-way annular cavity (517), and the diameter of the inlet of the two-way throttle hole (509) of the secondary control cavity is equal to the distance between the flange of the control valve (504) and the lower end face of the limit valve (503); the distance between the lower edge of the inlet of the two-way orifice (509) of the secondary control cavity and the upper edge of the low-pressure cavity (510) is equal to the distance between the flange of the control valve (504) and the lower end face of the limit valve (503); the distance from the upper edge of the secondary annular cavity (517) to the lower edge of the secondary annular cavity (517) is greater than the diameter of the inlet of the two-way orifice (509) of the secondary control cavity, and the diameter of the two-way orifice (508) of the secondary annular cavity is equal to the distance from the upper edge of the secondary annular cavity (517) to the lower edge of the secondary annular cavity (517).
6. The low oil return electric control fuel injector with variable fuel injection rules according to claim 1, characterized in that the distance from the upper edge of the low pressure cavity (510) to the lower edge of the secondary annular cavity (517) is equal to the distance between the flange of the control valve (504) and the lower end face of the limit valve (503), the distance between the lower end face of the electromagnet (501) and the upper end face of the armature (502) is greater than the maximum lift distance of the control valve (504), and the cross-sectional area of the control valve oil path (516) is greater than the sum of the inlet cross-sectional area of the secondary control cavity bi-directional orifice (509) and the inlet cross-sectional area of the primary control cavity bi-directional orifice (507).
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