阅读说明：本技术 一种控制阀下置式高压共轨喷油器及其方法 (Control valve underneath type high-pressure common rail oil injector and method thereof ) 是由 樊运运 胡薇 于 2019-11-13 设计创作，主要内容包括：本发明提供了一种控制阀下置式高压共轨喷油器及其方法,包括控制阀上座,控制阀下座,控制套筒和油针置于喷油器内腔下部,控制阀上座和控制阀下座密封连接,控制套筒位于控制阀下座下方,油针尾部置于控制套筒内,控制阀下座底部、控制套筒、油针顶部之间形成控制腔,控制腔位于喷油器下端位置；该方法包括以下步骤：S1:高压油分布；S2:无喷油关闭状态；S3:喷油器开启；S4:喷油器关闭。本发明的有益效果为：本发明控制阀上座,控制阀下座和控制套筒直接控制油针顶部的高压控制腔压力,快速、精确地控制油针向上和向下运动,取消控制阀杆后,加快了开启和关闭的速度,增加了喷油器单位时间内的喷油次数。(The invention provides a control valve underneath type high-pressure common rail oil sprayer and a method thereof, wherein the control valve underneath type high-pressure common rail oil sprayer comprises a control valve upper seat, a control valve lower seat, a control sleeve and an oil needle, wherein the control sleeve and the oil needle are arranged at the lower part of an inner cavity of the oil sprayer; the method comprises the following steps: s1, distributing high-pressure oil; s2, no oil injection closing state; s3, opening the oil sprayer; and S4, closing the fuel injector. The invention has the beneficial effects that: the upper seat, the lower seat and the control sleeve of the control valve directly control the pressure of the high-pressure control cavity at the top of the oil needle, quickly and accurately control the upward and downward movement of the oil needle, accelerate the opening and closing speed after a control valve rod is eliminated, and increase the oil injection times of the oil injector in unit time.)

1. A high-pressure common rail injector with a lower control valve comprises an injector body, a binding post injection mold arranged at the top of the injector body, two binding posts arranged on the binding post injection mold, an electromagnet wire sleeve is arranged at the upper section in the cavity of the oil sprayer body, guide cavities containing an electromagnet coil and an electromagnet spring are respectively arranged in the oil sprayer body at the bottom of the electromagnet wire sleeve, the bottom of the electromagnet spring is attached with an armature, the bottom of the armature is provided with a sealing hemisphere which is tightly contacted with the armature, it is characterized in that an upper seat and a lower seat of a control valve are respectively arranged from top to bottom on the bottom surface of the sealed hemisphere, the lower end of the lower control valve seat is provided with an oil needle, and a control sleeve, an oil needle spring and an oil needle spring gasket which surround the oil needle are sequentially arranged from top to bottom from the lower end of the lower control valve seat; an oil nozzle body communicated with the oil needle is arranged at the bottom of the oil needle, an oil nozzle tightening cap is arranged on the periphery of the oil nozzle body, and an oil nozzle spray hole is formed in the bottom of the oil nozzle body;

the control valve underneath type high-pressure common rail oil injector also comprises a control valve upper seat and a control valve lower seat which are positioned below the sealing hemisphere and sequentially penetrate through the control valve upper seat and the control valve lower seat, and a control valve upper seat oil outlet hole and a control valve lower seat oil outlet hole which are mutually communicated;

an electromagnet is arranged at the top of the upper seat of the control valve;

the contact part of the control valve upper seat oil outlet and the bottom surface of the sealed hemisphere is a control valve upper seat oil outlet small hole and a control valve lower seat oil outlet small hole which are communicated with the control valve upper seat oil outlet small hole;

a control sleeve oil inlet small hole is formed in one side of the control sleeve and communicated with a high-pressure control cavity between the oil needle and the lower seat of the control valve; an oil nozzle end surface oil groove is also arranged above the oil inlet small hole of the control sleeve, which is close to one side of the control sleeve;

and the oil injector body is provided with a high-pressure oil inlet and a low-pressure oil return port which are respectively communicated with the control valve upper seat high-pressure oil hole and the control valve upper seat low-pressure oil leakage hole.

2. The control valve underneath type high-pressure common rail injector according to claim 1, characterized in that the control valve upper seat, the control valve lower seat, the control sleeve and the oil needle are arranged at the lower part of an inner cavity of the injector, the control valve upper seat and the control valve lower seat are connected in a sealing manner, the control sleeve is arranged below the control valve lower seat, the tail part of the oil needle is arranged in the control sleeve, a control cavity is formed among the bottom of the control valve lower seat, the control sleeve and the top part of the oil needle, the control cavity is arranged at the lower end of the injector, and the control valve is of an up-and-down split type structure or an integrated type structure.

3. The control valve underneath type high-pressure common rail injector according to claim 1 or 2, characterized in that the oil outlet of the upper seat of the control valve is vertically arranged and is eccentric from the center of the diameter of the upper end face of the upper seat of the control valve, and the eccentric distance is 10% -50%; the oil outlet of the upper seat of the control valve is an inclined hole, and the included angle between the oil outlet and the lower end of the axis of the upper seat of the control valve is 10-50 degrees;

the oil inlet small hole of the control sleeve is positioned at 10% -50% of the upper end of the control sleeve.

4. The control valve lower high-pressure common rail injector according to any one of claims 1 to 3, characterized in that the control valve lower seat oil outlet hole and the control valve lower seat oil outlet small hole are both vertically arranged, and the control valve lower seat oil outlet small hole is located at 5% -50% of the position of the lower part of the control valve lower seat.

5. The control valve lower-mounted high-pressure common rail injector according to any one of claims 1 to 4, characterized in that the upper control valve seat and the lower control valve seat are connected to form a pressure stabilizing cavity with a thin upper part, a thick middle part and a thin lower part, the length of the pressure stabilizing cavity is 40-80% of the total length of the upper control valve seat and the lower control valve seat, and the volume of the pressure stabilizing cavity is 5-15mm³。

6. The control valve under-lying high-pressure common rail injector according to any one of claims 1 to 5, characterized in that the outer circumferential length of the upper section of the oil needle is within 50% of the total guide length of the control sleeve.

7. The control valve under-lying high-pressure common rail injector according to any one of claims 1 to 6, characterized in that the control sleeve oil inlet hole is located at the upper end thereof and has a height of 50% to 100%.

8. The control valve under-mount high pressure common rail injector according to any one of claims 1 to 7, wherein the control valve is sealed with an electromagnetically controlled armature assembly, and a ball seat provided by a ceramic hemisphere is separated from the armature.

9. The control valve under-positioned high-pressure common rail injector according to any one of claims 1 to 8, characterized in that a top of a guide cavity accommodating the electromagnet spring is provided with an electromagnet spring gasket.

10. A method of controlling a valve under mount high pressure common rail injector according to any one of claims 1 to 9, characterized by comprising the steps of:

s1, high-pressure oil distribution: high pressure oil generated by a high-pressure oil pump is stored in a common rail pipe, enters an oil injector from a high-pressure oil inlet through a high-pressure oil pipe, sequentially passes through an oil injector body and a control valve upper seat, enters an oil nozzle body high-pressure cavity after the control valve lower seat, enters a sealing area of an oil needle and an oil nozzle body through a clearance channel designed between a control sleeve and the oil nozzle body and a clearance channel designed between the oil needle and the oil nozzle body, and then enters a high-pressure control cavity at the top of the oil needle through an oil inlet small hole of the control sleeve;

s2, no oil injection closing state: after the high-pressure oil is distributed in the oil sprayer, the top and the lower part of the oil needle are both high-pressure areas, and the stress area of the high-pressure oil at the top of the oil needle is larger than that of the lower part, so that the generated hydraulic resultant force is downward, the sealing between the oil needle and the oil nozzle body is ensured, and the oil sprayer is in a closed state;

and S3, opening a fuel injector: when the ECU powers on the electromagnet coil through the binding post, the armature is attracted by the electromagnet due to the electromagnetic force and moves upwards, so that the sealing force between the sealing hemisphere and the upper seat of the control valve is lost, high-pressure oil distributed in a high-pressure control cavity at the top of the oil needle leaks greatly in the sealing area of the sealing hemisphere and the upper seat of the control valve, the pressure in the high-pressure control cavity at the top of the oil needle is suddenly reduced due to the fact that an oil outlet small hole of the upper seat of the control valve and an oil outlet small hole of a lower seat of the control valve are in a communicated state, the pressure of the high-pressure oil at the lower part of the oil needle is not reduced, so that the hydraulic pressure of the lower part of the oil needle is greater than that of the upper part of the oil needle, the oil needle moves upwards, the;

s4, closing the oil sprayer: when the ECU powers off the electromagnet, the armature moves downwards under the action of the spring force of the electromagnet, the sealing hemisphere and the upper seat of the control valve are sealed again, high-pressure oil is filled into the high-pressure control cavity at the top of the oil needle, so that the top of the oil needle forms a high-pressure cavity again, the generated hydraulic resultant force is downward in the direction, the oil needle moves downwards until the oil needle is sealed again between the oil nozzle bodies, and the oil injector is closed.

Technical Field

The invention relates to the technical field of oil injectors, in particular to a high-pressure common rail oil injector with a control valve arranged below and a method thereof.

Background

With the continuous upgrading of national automobile emission regulations and oil consumption regulations, higher technical requirements are put forward on a diesel common rail system for helping to improve the combustion efficiency and the tail gas quality of fuel oil. The concrete aspects are as follows: 1) and high-pressure injection: the pressure of a mainstream injection system discharged by the six countries at present is 1800-2000 bar, the injection pressure of 2500bar is adopted in some engine types, and the pressure requirement of a follow-up advanced engine can reach 3000 bar. 2) And accurate injection: timing and quantification are carried out, the small oil injection dispersion difference is ensured, and the stable time interval of multiple injections is short. 3) Low energy loss: the design of the oil injector avoids static leakage loss and reduces dynamic leakage loss, thereby reducing the energy consumption of the system and the invalid power consumption of the engine. 4) And high reliability: the product needs to avoid pressure pulse fatigue failure within the life span and ensure high pressure tightness while reducing the risk of cavitation and wear of the high pressure working components. 5) Easy workability: with the increasing requirement of the injection pressure, higher requirements are put on the processing precision of parts, so that the structural design needs to be optimized, and the processing cost and the equipment investment are reduced. 6) Product consistency: due to stricter engine factory emissions and power requirements, product consistency between injectors needs to be achieved. 7) And reproducibility: with the increase of human resource cost and material cost, in order to achieve the goal of saving energy consumption, the fuel injector is required to have a low-cost renewable scheme.

Therefore, although the 2000bar pressure oil injector of the electric device in japan or delford in usa in germany is already the mainstream product of an engine or a whole car factory in the market of china, the electromagnet is still kept at the top of the oil injector, namely the electromagnet is arranged on the top, and the valve rod is used as the design of a moving part connected between the control valve and the oil needle, so that the injection response speed is limited to a certain extent, the number of parts of the oil injector is increased, the production cost is increased, and the upgrade optimization space is obviously provided.

As shown in the attached figure 3, the fuel injector is a german Boshi fuel injector which is widely used in China at present, and refers to the structure and the principle of Jinghong (electronically controlled diesel engine) and the structure composition of the fuel injector of people's traffic publishing agency: 101. an electromagnet; 102. an armature assembly; 103. sealing the small ball; 104. a control valve; 105. a control valve stem; 106. an oil needle; 107. a high pressure oil inlet; 108. a control valve high pressure oil hole; 109. an oil needle high-pressure oil duct; 110. nozzle holes of the oil nozzle; 111. an electrical connector; 112. a nipple body; 113. an electromagnet spring.

The working process of the oil injector is explained in detail;

1. high-pressure oil distribution:

high-pressure oil generated by the high-pressure oil pump is stored in the high-pressure common rail pipe, enters the oil sprayer from the high-pressure oil inlet through the high-pressure oil pipe, and is divided into two paths after entering the oil sprayer, wherein the upper path enters the control valve through the high-pressure oil duct of the control valve, and the lower path enters the oil needle through the high-pressure oil duct of the oil needle.

2. No-injection off state:

after the high-pressure oil is distributed in the oil sprayer, the top of the control valve rod and the lower part of the oil needle are both high-pressure areas, and the stress area of the high-pressure oil on the top of the control valve rod is larger than that of the high-pressure oil on the lower part of the oil needle, so that the generated hydraulic resultant force is downward, the sealing of the oil needle and the oil nozzle body is ensured, and the oil sprayer is in a closed state.

3. Opening the oil injector:

when the ECU powers the electromagnet through the electric connector, the armature component moves upwards due to the electromagnetic force, so that the sealing small ball loses the sealing force, high-pressure oil distributed on the top of the control valve rod forms a large amount of leakage at the sealing surfaces of the sealing small ball and the control valve, the oil pressure on the top of the control valve rod is reduced rapidly, but the high-pressure oil pressure on the lower way of the oil needle is unchanged, so that the hydraulic pressure on the lower way of the oil needle is larger than the hydraulic pressure on the top of the control valve rod, the oil needle and the control valve rod move upwards together, the oil needle and the oil nozzle body are not sealed again, a high-pressure oil channel is formed, the high-pressure oil enters the oil nozzle spray hole.

4. Closing the oil injector:

when the ECU finishes electrifying the electromagnet, the armature component moves downwards under the action of the spring force of the electromagnet spring, so that the sealing ball and the control valve return to a sealing state, and meanwhile, high-pressure oil enters the top of the control valve rod through the high-pressure oil hole of the control valve, so that a high-pressure cavity is formed at the top of the control valve rod again. Because the high-pressure oil stress area at the top of the control valve rod is larger than that of the high-pressure oil at the lower part of the oil needle, the generated hydraulic resultant force is downward in direction, so that the oil needle moves downward until the oil needle and the oil nozzle body form sealing again, and the oil injector is closed.

From the above-mentioned german bosch injector technology, it can be concluded that the technical disadvantages include the following aspects:

1. the fuel injection response speed is slow: the control valve rod is arranged between the control valve and the oil needle of the oil injector, so that the whole hydraulic moving part has large mass, and the opening and closing movement response is slow and the speed is low under the action of the same hydraulic pressure; the number of injections per unit time is limited.

2. Poor oil injection precision: because the control valve rod is arranged between the control valve and the oil needle of the oil injector, and the control valve rod and the control valve have gap guide, under different pressure states, the size of the gap directly influences the size of friction force, so that the movement consistency of the control valve rod is poor, the opening and closing speed of the oil injector is influenced, and the control precision of the oil injection quantity is reduced.

3. Limiting the maximum pressure of the oil injector: because the control valve rod is arranged between the control valve and the oil needle of the oil injector, under the condition of pressure rise, the control valve rod can be subjected to larger hydraulic pressure, and because the control valve rod is longer in length, bending deformation can be generated, clamping stagnation and abrasion are easy to occur, and the application possibility of 2500bar or even 3000bar is limited by the risk.

4. The processing cost is high: the control valve rod is a precision workpiece, and the lengths of the control valve rod are different according to different engines, so that the type and the model of the control valve rod are complex, and high processing cost is caused.

5. Low reliability: because the cavitation risk of the control valve is not effectively avoided, a large number of control valve sealing surface failure oil injectors exist on the market. Meanwhile, because the control valve rod bears high hydraulic load, a large amount of control valve rods on the market are abraded to cause failure of the oil injector.

How to solve the above technical problems is the subject of the present invention.

Disclosure of Invention

The invention aims to provide a high-pressure common rail oil sprayer with a lower control valve and a method thereof.

The invention is realized by the following measures: a high-pressure common rail oil injector with a control valve arranged at the bottom comprises an oil injector body 7, a terminal injection mold 2 arranged at the top of the oil injector body 7, two terminals 1 positioned on the terminal injection mold 2, an electromagnet guide wire sleeve 3 arranged at the upper section in the cavity of the oil injector body 7, a guide cavity containing an electromagnet coil 4 and an electromagnet spring 5 arranged at the bottom of the electromagnet guide wire sleeve 3, an armature 8 attached to the bottom of the electromagnet spring 5, and a sealing hemisphere 9 tightly contacted with the armature 8 arranged at the bottom of the armature 8, wherein a control valve upper seat 10 and a control valve lower seat 11 are sequentially arranged from top to bottom on the bottom surface of the sealing hemisphere 9, an oil needle 15 is arranged at the lower end of the control valve lower seat 11, and a control sleeve 12 surrounding the oil needle 15 is sequentially arranged from top to bottom of the control valve lower seat 11, An oil needle spring 13 and an oil needle spring washer 14; an oil nozzle body 16 communicated with the oil needle 15 is arranged at the bottom of the oil needle 15, an oil nozzle fastening cap 17 is arranged on the periphery of the oil nozzle body 16, and an oil nozzle spray hole 32 is arranged at the bottom of the oil nozzle body 16;

the control valve underneath type high-pressure common rail oil injector further comprises a control valve upper seat oil outlet hole 36 and a control valve lower seat oil outlet hole 35 which are positioned below the sealing hemisphere 9 and sequentially penetrate through the control valve upper seat 10 and the control valve lower seat 11 and are communicated with each other, one side of the control valve upper seat 10 and one side of the control valve lower seat 11 are provided with a control valve upper seat high-pressure oil hole 39, a control valve upper seat low-pressure oil leakage hole 40, a control valve lower seat high-pressure oil hole 38 and a control valve lower seat low-pressure oil leakage hole 42, the control valve upper seat high-pressure oil hole 39 is communicated with the control valve lower seat high-pressure oil hole 38, and the control valve upper seat low-pressure oil leakage hole 40 is communicated with the control valve lower seat low-pressure oil leakage hole 42;

the top of the control valve upper seat 10 is provided with an electromagnet 41;

the contact part of the control valve upper seat oil outlet hole 36 and the bottom surface of the sealed hemisphere 9 is a control valve upper seat oil outlet small hole 37 and a control valve lower seat oil outlet small hole 34 which are communicated with the control valve upper seat oil outlet hole;

a control sleeve oil inlet small hole 33 is formed in one side of the control sleeve 12, and the control sleeve oil inlet small hole 33 is communicated with a high-pressure control cavity 31 between the oil needle 15 and the control valve lower seat 11; a nozzle end surface oil groove 43 is further arranged above the control sleeve oil inlet small hole 33 close to one side of the control sleeve 12;

and a high-pressure oil inlet 18 and a low-pressure oil return port 19 which are respectively communicated with the control valve upper seat high-pressure oil hole 39 and the control valve upper seat low-pressure oil leakage hole 40 are arranged on the oil injector body 7.

As a further optimization scheme of the control valve underneath type high-pressure common rail injector provided by the invention, the control valve upper seat 10, the control valve lower seat 11, the control sleeve 12 and the oil needle 15 are arranged at the lower part of an inner cavity of the injector, the control valve upper seat 10 and the control valve lower seat 11 are hermetically connected, the control sleeve 12 is arranged below the control valve lower seat 11, the tail part of the oil needle 15 is arranged in the control sleeve 12, a control cavity is formed among the bottom of the control valve lower seat 11, the control sleeve 12 and the top of the oil needle 15, the control cavity is arranged at the lower end of the injector, and the control valve is of an up-and-down split type structure or an integrated structure.

As a further optimization scheme of the control valve underneath type high-pressure common rail oil sprayer provided by the invention, the oil outlet hole 36 of the upper seat of the control valve is vertically arranged, the position of the oil outlet hole is eccentric to the diameter center position of the upper end face of the upper seat 10 of the control valve, and the eccentric distance is 10-50%; the oil outlet 36 of the upper seat of the control valve is an inclined hole, and the included angle between the inclined hole and the lower end of the axis of the upper seat 10 of the control valve is 10-50 degrees;

the control sleeve oil inlet small hole 33 is located at 10% -50% of the upper end of the control sleeve 12.

As a further optimization scheme of the control valve underneath type high-pressure common rail injector provided by the invention, the control valve lower seat oil outlet hole 35 and the control valve lower seat oil outlet small hole 34 are both vertically arranged, and the control valve lower seat oil outlet small hole 34 is positioned at 5% -50% of the lower part of the control valve lower seat 10.

As a further optimization scheme of the control valve underneath type high-pressure common rail oil injector provided by the invention, the control valve upper seat 10 and the control valve lower seat 11 are connected to form a structureThe pressure stabilizing cavity is thin at the upper part, thick at the middle part and thin at the lower part, the length of the pressure stabilizing cavity is 40-80 percent of the total length of the upper seat 10 and the lower seat 11 of the control valve, and the volume of the pressure stabilizing cavity is 5-15mm³。

As a further optimization scheme of the control valve underneath type high-pressure common rail injector provided by the invention, the length of the outer circle of the upper section of the oil needle 15 is within 50% of the total guide length of the control sleeve 12.

As a further optimization scheme of the control valve underneath type high-pressure common rail oil sprayer provided by the invention, the oil inlet hole of the control sleeve is positioned at the upper end of the control sleeve, and the height of the oil inlet hole is 50% -100%.

As a further optimization scheme of the control valve underneath type high-pressure common rail oil injector provided by the invention, the control valve is sealed by adopting an electromagnetic control armature component, and a ball seat arranged on a ceramic hemisphere is separated from an armature.

As a further optimization scheme of the control valve underneath type high-pressure common rail oil sprayer provided by the invention, an electromagnet spring gasket 6 is arranged at the top of a guide cavity for accommodating the electromagnet spring 5.

In order to better achieve the purpose of the invention, the invention also provides a method for controlling the valve underneath type high-pressure common rail injector, which mainly comprises the following steps:

s1, high-pressure oil distribution: high pressure generated by a high-pressure oil pump is stored in a common rail pipe, enters an oil injector from a high-pressure oil inlet through a high-pressure oil pipe, sequentially passes through an oil injector body 7, a control valve upper seat 10 and a control valve lower seat 11, then enters a high-pressure cavity of an oil nozzle body 7, and enters a high-pressure control cavity at the top of the oil nozzle body 15 through a clearance channel designed between a control sleeve 12 and the oil nozzle body 16 and a clearance channel designed between the oil needle 15 and the oil nozzle body 16, and then enters a sealing area of the oil needle 15 and the oil nozzle body 16 through an oil inlet small hole 33 of the control sleeve;

s2, no oil injection closing state: after the high-pressure oil is distributed in the oil injector, the top and the lower part of the oil needle 15 are high-pressure areas, and the stress area of the high-pressure oil at the top of the oil needle 15 is larger than that of the lower part, so that the direction of the generated hydraulic resultant force is downward, the sealing between the oil needle 15 and the oil nozzle body 16 is ensured, and the oil injector is in a closed state;

and S3, opening a fuel injector: when the ECU energizes the electromagnet coil 4 through the binding post 1, the armature 8 is attracted by the electromagnet due to the electromagnetic force, and moves upwards, so that the sealing force between the sealing hemisphere 9 and the control valve upper seat 10 is lost, the high-pressure oil distributed in the high-pressure control cavity at the top of the oil needle 15 leaks a large amount in the sealing area between the sealing hemisphere 9 and the control valve upper seat 10, because the control valve upper seat oil outlet small hole 37 and the control valve lower seat oil outlet small hole 34 are in a communicated state, the pressure in the high-pressure control cavity at the top of the oil needle 15 is suddenly reduced, the high-pressure oil pressure at the lower part of the oil needle 15 is not reduced, so that the hydraulic pressure at the lower part of the oil needle 15 is greater than the hydraulic pressure at the upper part of the oil needle 15, the oil needle 15 moves upwards, the oil needle 15 and the oil nozzle body 16 are not sealed again, an;

s4, closing the oil sprayer: when the ECU powers off the electromagnet, the armature 8 moves downwards under the action of the spring force of the electromagnet, the sealing hemisphere 9 and the control valve upper seat 10 are sealed again, high-pressure oil is filled into a high-pressure control cavity at the top of the oil needle 15, so that the top of the oil needle 15 forms a high-pressure cavity again, the generated hydraulic resultant force is downward in the direction because the stress area of the high-pressure oil at the top of the oil needle 15 is larger than that of the lower part, the oil needle 15 moves downwards until the oil needle 15 is sealed again between the oil nozzle bodies 16, and the oil injector is closed.

The invention has the beneficial effects that:

1. the electromagnet of the invention is arranged below: in the traditional oil sprayer, an electromagnet is positioned at the top of the oil sprayer, the electromagnetic force generated by the electromagnet and the spring force of an electromagnet spring are used for realizing the up-and-down movement of an armature, and the pressure of a control cavity of a control valve is controlled through a sealing small ball. And a control valve rod is arranged between the control valve and the oil needle and used for transmitting hydraulic pressure to control the opening and closing of the oil needle. Because the electromagnet is far away from the oil needle, the oil needle belongs to a high-precision part, the design length is short, and once the length of the oil needle is too long, the machining precision of other sizes of the oil needle can be influenced, so that the control valve rod is necessary. The distance between the electromagnet and the oil needle is shortened by arranging the electromagnet below, so that control valve parts can be cancelled, and the direct control of the control valve on the oil needle is realized.

2. The upper seat of the control valve, the lower seat of the control valve and the control sleeve directly control the pressure of the high-pressure control cavity at the top of the oil needle, so that the upward and downward movement of the oil needle is quickly and accurately controlled, the mass of a moving part is greatly reduced after a control valve rod is omitted, the opening and closing speed is accelerated, the oil injection frequency of the oil injector in unit time is increased, and the fuel economy and the emission quality of an engine can be improved. On the other hand, the control valve rod is eliminated, the movement inconsistency caused by the gap between the control valve rod and the control valve is effectively avoided, and the injection precision is improved.

3. The control valve upper seat, the control valve lower seat and the control sleeve directly control the pressure of the high-pressure control cavity at the top of the oil needle, after the control valve rod is cancelled, the bending deformation risk caused by the longer length of the control valve rod is avoided, and the oil needle is small in high-pressure deformation risk caused by the shorter length, so that the design can be applied to 2500bar or even 3000 bar.

4. The small oil outlet hole of the lower control valve seat, the oil outlet hole of the upper control valve seat and the small oil outlet hole of the upper control valve seat are unique in design, and reliability of the control valve can be improved. As is known well, in the traditional design of the oil injector, after a small sealing ball is opened, the pressure of a high-pressure control cavity can be rapidly reduced, a cavitation flow field is generated, cavitation damage is generated on the small sealing ball and a sealing surface of a control valve, the sealing of the sealing surface fails, and the oil injection function of the oil injector fails. Cavitation damage is also exacerbated as the pressure increases. But the design of present case, the independent processing can be realized to control valve upper bracket and control valve lower bracket, in the operating mode, the cavitation bubble that the control valve lower bracket oil outlet aperture formed, because the reduction of the aperture department flow area that produces oil of control valve upper bracket, pressure rises, cause the bubble mainly to distribute in the oil outlet inner wall of control valve upper bracket, form the gathering in this region and extrude the blasting, can not cause the cavitation damage to the sealed face of sealed hemisphere and control valve upper bracket, thereby the reliability of sealed face has been improved greatly, the normal opening and closing of sprayer have been guaranteed, the reliability of sprayer has been improved. Simultaneously, compare in traditional design, through avoiding sealed face cavitation erosion injury, make this design can apply to 2500bar even 3000 bar.

5. Design of the control sleeve: traditional sprayer, control valve oil feed aperture are located the control valve, have caused the control valve structure complicacy, and the processing degree of difficulty is with high costs, and the control sleeve of present case design, simple structure, oil feed aperture are located the first half of control sleeve, make it have the machinability that many hydraulic grinding simultaneously, low in production cost.

6. Designing the top of the oil needle: according to the oil inlet small hole of the control sleeve, the top of the oil needle is specially designed, the diameter of the top of the oil needle is reduced, high-pressure oil can enter a high-pressure control cavity from the oil inlet small hole of the control sleeve, the top of the oil needle and a gap between the control sleeve and a control sleeve sword at any position of the up-and-down movement of the oil needle, pressure control of the control cavity is achieved, and therefore opening and closing control of an oil injector is guaranteed.

Drawings

Fig. 1 is a schematic diagram of the overall structure of a fuel injector according to the present invention.

Fig. 2 is a view of the lower structure of the injector of fig. 1.

Fig. 3 is a schematic structural diagram of a conventional bosch fuel injector.

Wherein the reference numerals are: 1. a binding post; 2. a binding post injection mold; 3. an electromagnet wire sleeve; 4. an electromagnet coil; 41. an electromagnetic core; 5. an electromagnet spring; 6. an electromagnet spring spacer; 7. an injector body; 8. an armature; 9. sealing the hemisphere; 10. a control valve upper seat; 11. a lower seat of the control valve; 12. a control sleeve; 13. an oil needle spring; 14. an oil needle spring washer; 15. an oil needle; 16. a nipple body; 17. tightening a cap of the oil nozzle; 18. a high pressure oil inlet; 19. a low pressure oil return port; 31. a high pressure control chamber; 32. nozzle holes of the oil nozzle; 33. controlling the sleeve to enter the oil small hole; 34. the control valve lower seat oil outlet small hole 35 and the control valve lower seat oil outlet; 36. an oil outlet of the upper seat of the control valve; 37. an oil outlet small hole of the upper seat of the control valve; 38. a control valve lower seat high-pressure oil hole; 39. a control valve upper seat high-pressure oil hole; 40. a low-pressure oil leakage hole of the upper seat of the control valve; 41. a low-pressure oil return groove of the upper seat of the control valve; 42. a low-pressure oil leakage hole of a lower seat of the control valve; 43. the oil nozzle end face oil groove.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.

Referring to fig. 1-2, the present invention is: a high-pressure common rail oil injector with a control valve arranged at the bottom comprises an oil injector body 7, a terminal injection mold 2 arranged at the top of the oil injector body 7, two terminals 1 positioned on the terminal injection mold 2, an electromagnet guide wire sleeve 3 arranged at the upper section in the cavity of the oil injector body 7, a guide cavity containing an electromagnet coil 4 and an electromagnet spring 5 arranged at the bottom of the electromagnet guide wire sleeve 3, an armature 8 attached to the bottom of the electromagnet spring 5, and a sealing hemisphere 9 tightly contacted with the armature 8 arranged at the bottom of the armature 8, wherein a control valve upper seat 10 and a control valve lower seat 11 are sequentially arranged from top to bottom on the bottom surface of the sealing hemisphere 9, an oil needle 15 is arranged at the lower end of the control valve lower seat 11, and a control sleeve 12 surrounding the oil needle 15 is sequentially arranged from top to bottom of the control valve lower seat 11, An oil needle spring 13 and an oil needle spring washer 14; an oil nozzle body 16 communicated with the oil needle 15 is arranged at the bottom of the oil needle 15, an oil nozzle fastening cap 17 is arranged on the periphery of the oil nozzle body 16, and an oil nozzle spray hole 32 is arranged at the bottom of the oil nozzle body 16;

the control valve underneath type high-pressure common rail oil injector further comprises a control valve upper seat oil outlet hole 36 and a control valve lower seat oil outlet hole 35 which are positioned below the sealing hemisphere 9 and sequentially penetrate through the control valve upper seat 10 and the control valve lower seat 11 and are communicated with each other, one side of the control valve upper seat 10 and one side of the control valve lower seat 11 are provided with a control valve upper seat high-pressure oil hole 39, a control valve upper seat low-pressure oil leakage hole 40, a control valve lower seat high-pressure oil hole 38 and a control valve lower seat low-pressure oil leakage hole 42, the control valve upper seat high-pressure oil hole 39 is communicated with the control valve lower seat high-pressure oil hole 38, and the control valve upper seat low-pressure oil leakage hole 40 is communicated with the control valve lower seat low-pressure oil leakage hole 42;

the top of the control valve upper seat 10 is provided with an electromagnet 41;

the contact part of the control valve upper seat oil outlet hole 36 and the bottom surface of the sealed hemisphere 9 is a control valve upper seat oil outlet small hole 37 and a control valve lower seat oil outlet small hole 34 which are communicated with the control valve upper seat oil outlet hole;

a control sleeve oil inlet small hole 33 is formed in one side of the control sleeve 12, and the control sleeve oil inlet small hole 33 is communicated with a high-pressure control cavity 31 between the oil needle 15 and the control valve lower seat 11; a nozzle end surface oil groove 43 is further arranged above the control sleeve oil inlet small hole 33 close to one side of the control sleeve 12;

and a high-pressure oil inlet 18 and a low-pressure oil return port 19 which are respectively communicated with the control valve upper seat high-pressure oil hole 39 and the control valve upper seat low-pressure oil leakage hole 40 are arranged on the oil injector body 7.

Specifically, the upper control valve seat 10, the lower control valve seat 11, the control sleeve 12 and the oil needle 15 are arranged on the lower portion of an inner cavity of the oil injector, the upper control valve seat 10 is connected with the lower control valve seat 11 in a sealing mode, the control sleeve 12 is located below the lower control valve seat 11, the tail portion of the oil needle 15 is arranged in the control sleeve 12, a control cavity is formed among the bottom of the lower control valve seat 11, the control sleeve 12 and the top of the oil needle 15 and located at the lower end of the oil injector, and the control valve is of an upper-lower split type structure or an integrated type structure.

Specifically, the control valve upper seat oil outlet hole 36 is vertically arranged, the position of the control valve upper seat oil outlet hole is eccentric to the diameter center position of the upper end face of the control valve upper seat 10, and the eccentric distance is 10% -50%; the oil outlet 36 of the upper seat of the control valve is an inclined hole, and the included angle between the inclined hole and the lower end of the axis of the upper seat 10 of the control valve is 10-50 degrees;

the control sleeve oil inlet small hole 33 is located at 10% -50% of the upper end of the control sleeve 12.

Specifically, the control valve lower seat oil outlet hole 35 and the control valve lower seat oil outlet small hole 34 are both vertically arranged, and the control valve lower seat oil outlet small hole 34 is located at 5% -50% of the lower portion of the control valve lower seat 10.

Specifically, the upper control valve seat 10 and the lower control valve seat 11 are connected to form a pressure stabilizing cavity with a thin upper part, a thick middle part and a thin lower part, the length of the pressure stabilizing cavity is 40% -80% of the total length of the upper control valve seat 10 and the lower control valve seat 11, and the volume of the pressure stabilizing cavity is 5-15mm³。

Specifically, the length of the outer circle of the upper section of the oil needle 15 is within 50% of the total guide length of the control sleeve 12.

Specifically, the oil inlet hole of the control sleeve is positioned at the upper end of the control sleeve, and the height of the oil inlet hole is 50% -100%.

Specifically, the control valve is sealed with a solenoid-operated armature assembly, with a ball seat provided by a ceramic hemisphere spaced from the armature.

Specifically, the top of the guide cavity accommodating the electromagnet spring 5 is provided with an electromagnet spring gasket 6.

In order to better achieve the purpose of the invention, the invention also provides a method for controlling the valve underneath type high-pressure common rail injector, which mainly comprises the following steps:

s1, high-pressure oil distribution: high pressure generated by a high-pressure oil pump is stored in a common rail pipe, enters an oil injector from a high-pressure oil inlet through a high-pressure oil pipe, sequentially passes through an oil injector body 7, a control valve upper seat 10 and a control valve lower seat 11, then enters a high-pressure cavity of an oil nozzle body 7, and enters a high-pressure control cavity at the top of the oil nozzle body 15 through a clearance channel designed between a control sleeve 12 and the oil nozzle body 16 and a clearance channel designed between the oil needle 15 and the oil nozzle body 16, and then enters a sealing area of the oil needle 15 and the oil nozzle body 16 through an oil inlet small hole 33 of the control sleeve;

s2, no oil injection closing state: after the high-pressure oil is distributed in the oil injector, the top and the lower part of the oil needle 15 are high-pressure areas, and the stress area of the high-pressure oil at the top of the oil needle 15 is larger than that of the lower part, so that the direction of the generated hydraulic resultant force is downward, the sealing between the oil needle 15 and the oil nozzle body 16 is ensured, and the oil injector is in a closed state;

and S3, opening a fuel injector: when the ECU energizes the electromagnet coil 4 through the binding post 1, the armature 8 is attracted by the electromagnet due to the electromagnetic force, and moves upwards, so that the sealing force between the sealing hemisphere 9 and the control valve upper seat 10 is lost, the high-pressure oil distributed in the high-pressure control cavity at the top of the oil needle 15 leaks a large amount in the sealing area between the sealing hemisphere 9 and the control valve upper seat 10, because the control valve upper seat oil outlet small hole 37 and the control valve lower seat oil outlet small hole 34 are in a communicated state, the pressure in the high-pressure control cavity at the top of the oil needle 15 is suddenly reduced, the high-pressure oil pressure at the lower part of the oil needle 15 is not reduced, so that the hydraulic pressure at the lower part of the oil needle 15 is greater than the hydraulic pressure at the upper part of the oil needle 15, the oil needle 15 moves upwards, the oil needle 15 and the oil nozzle body 16 are not sealed again, an;

s4, closing the oil sprayer: when the ECU powers off the electromagnet, the armature 8 moves downwards under the action of the spring force of the electromagnet, the sealing hemisphere 9 and the control valve upper seat 10 are sealed again, high-pressure oil is filled into a high-pressure control cavity at the top of the oil needle 15, so that the top of the oil needle 15 forms a high-pressure cavity again, the generated hydraulic resultant force is downward in the direction because the stress area of the high-pressure oil at the top of the oil needle 15 is larger than that of the lower part, the oil needle 15 moves downwards until the oil needle 15 is sealed again between the oil nozzle bodies 16, and the oil injector is closed.

The specific working process of the oil sprayer is as follows:

1) high-pressure oil distribution: high pressure generated by the high-pressure oil pump is stored in the common rail pipe, enters the oil injector from the high-pressure oil inlet through the high-pressure oil pipe, sequentially passes through the oil injector body 7, the upper seat 10 of the control valve and the lower seat 11 of the control valve, and then enters the high-pressure cavity of the oil nozzle body 7. On one hand, high-pressure oil enters a sealing area of the oil needle 15 and the oil nozzle body 16 through a gap channel designed between the control sleeve 12 and the oil nozzle body 16 and a gap channel designed between the oil needle 15 and the oil nozzle body 16, and on the other hand, the high-pressure oil enters a high-pressure control cavity at the top of the oil needle 15 through the control sleeve oil inlet small hole 33;

2) no-injection off state: after the high-pressure oil is distributed in the oil injector, the top and the lower part of the oil needle 15 are high-pressure areas, and the stress area of the high-pressure oil at the top of the oil needle 15 is larger than that of the lower part, so that the generated hydraulic resultant force is downward, the sealing between the oil needle 15 and the oil nozzle body 16 is ensured, and the oil injector is in a closed state;

3) opening the oil injector: when the ECU energizes the electromagnet coil 4 through the wiring terminal 1, the armature 8 is attracted by the electromagnet due to the electromagnetic force and moves upwards, so that the sealing force between the sealing hemisphere 9 and the control valve upper seat 10 is lost, high-pressure oil distributed in a high-pressure control cavity at the top of the oil needle 15 leaks greatly in the sealing area between the sealing hemisphere 9 and the control valve upper seat 10, and the pressure in the high-pressure control cavity at the top of the oil needle 15 drops suddenly due to the fact that the control valve upper seat oil outlet small hole 37 and the control valve lower seat oil outlet small hole 34 are in a communicated state. However, the high-pressure oil pressure at the lower part of the oil needle 15 is not reduced, so that the hydraulic pressure borne by the lower part of the oil needle 15 is larger than the hydraulic pressure borne by the upper part of the oil needle 15, the oil needle 15 moves upwards, the oil needle 15 and the oil nozzle body 16 are not sealed, an oil passage is formed, and the high-pressure oil enters the oil nozzle spray hole 32 oil injector to realize oil injection;

4) closing the oil injector: when the ECU powers off the electromagnet, the armature 8 moves downwards under the action of the spring force of the electromagnet, the resealing of the sealing hemisphere 9 and the upper seat 10 of the control valve is realized, and simultaneously, high-pressure oil supplementarily enters a high-pressure control cavity at the top of the oil needle 15, so that the top of the oil needle 15 forms a high-pressure cavity again. Because the stress area of the high-pressure oil at the top of the oil needle 15 is larger than that at the lower part, the generated hydraulic resultant force is downward, the oil needle 15 moves downward until the oil needle 15 is sealed again between the oil nozzle bodies 16, and the oil injector is closed.

The technical features of the present invention which are not described in the above embodiments may be implemented by or using the prior art, and are not described herein again, of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions or substitutions which may be made by those skilled in the art within the spirit and scope of the present invention should also fall within the protection scope of the present invention.