WO2022247098A1

WO2022247098A1 - Two-stage rotational flow urea ejector

Info

Publication number: WO2022247098A1
Application number: PCT/CN2021/122941
Authority: WO
Inventors: 欧阳玲湘; 李成校; 邓飞; 龙美彪; 黄民备
Original assignee: 南岳电控衡阳工业技术股份有限公司
Priority date: 2021-05-23
Filing date: 2021-10-10
Publication date: 2022-12-01
Also published as: ZA202309881B; CN113279845A; CN113279845B

Abstract

A two-stage rotational flow urea ejector, comprising a nozzle body (4), a valve rod (5), a valve seat (2), a nozzle plate (1), and a steel ball (3). A plurality of inclined holes (204) are provided in the valve seat (2), and the center of each inclined hole (204) is eccentrically arranged relative to the central axis of the valve seat (2); a plurality of rotational flow grooves (208) and a rotational flow hole (210) are provided in the lower surface of the valve seat (2), and the rotational flow hole (210) is located in the center of the lower surface of the valve seat (2) and is coaxially communicated with a round hole of the nozzle plate (1); a first end of each inclined hole (204) is communicated with a flow-through hole (203), a first end of each rotational flow groove (208) is communicated with a second end of the corresponding inclined hole (204), and a second end of each rotational flow groove (208) is communicated with the rotational flow hole (210). The two-stage rotational flow urea ejector has the advantages that the particle size of atomized particles can be improved, the flow consistency is improved, the structure is simple and reasonable, manufacturing and assembling are facilitated, and the production cost is low.

Description

A two-stage swirl urea injector

technical field

The invention belongs to the technical field of automobile manufacturing, in particular to a two-stage swirl urea injector.

Background technique

Selective Catalytic Reduction (Selective Catalytic Reduction) referred to as SCR, SCR refers to a catalytic reduction device installed in the exhaust system of diesel vehicles to catalytically reduce NOx in diesel engine emissions into N ₂ and H ₂ O, and urea aqueous solution is selected as the reducing agent . In the SCR system, the urea injector sprays the urea aqueous solution into the exhaust pipe regularly and quantitatively. The better the atomization effect of the urea aqueous solution, the more sufficient the exhaust gas reaction can be, and it is not easy to crystallize. In actual use, due to poor atomization effect in the post-treatment system, urea crystallization blockage frequently occurs, resulting in excessive emissions or insufficient vehicle power.

The Chinese utility model patent application number is CN201920410691.0, which discloses a urea solution atomizing electromagnetic metering injector, which has a porous structure, and multiple centrifugal turbulent flow chambers are arranged between the end of the valve seat and the orifice plate. The turbulent flow generated by the centrifugal turbulent chamber improves the atomization effect, and finally sprays out from the corresponding nozzle hole. With the improvement of discharge requirements, the particle size requirements of spray particles are getting higher and higher. The atomization effect of this structure is difficult to meet the current requirements. It is difficult to ensure the consistency of atomized particle size between holes, and the flow consistency and processing technology are poor.

The Chinese invention patent application number applied by the applicant is CN202110329521.1, which discloses a low-hydraulic swirl injector. Its structure is a single-hole swirl structure. One side is provided with diversion counterbore and several diverter grooves, and the outer circle of the swirl plate is provided with flat squares corresponding to the diverter grooves, which are used for fluid flow passages, and the other side of the swirl plate is provided with swirl holes and several swirl holes. Slot, after the diversion fluid passes through the swirl slot, there will be severe impact and turbulent flow, which will converge into the swirl hole, and the particle size of the atomized particles will be significantly increased. This structure only has a single-stage swirl flow at the front end of the injection. Although the spray effect has been significantly improved and the flow consistency is better, the atomization particle size needs to be further increased so that the urea aqueous solution can fully contact and mix with the exhaust gas after atomization. , so as to solve the problem of crystallization blockage in the urea system.

Contents of the invention

The purpose of the present invention is to solve the technical problems existing in the existing products, and provide a two-stage swirl urea injector structure, which adopts the single-hole swirl injection mode, which can significantly increase the atomized particle size of the urea aqueous solution and improve the flow consistency , and has the advantages of simple and reasonable structure, convenient manufacture and assembly, and low production cost.

In order to realize the foregoing invention object, the specific technical scheme provided by the present invention is as follows:

A two-stage swirl urea injector at least includes a nozzle body, a valve stem, a valve seat, a nozzle plate, and steel balls, the nozzle body has an inner hole, and the valve stem, valve seat, nozzle plate, and steel balls are all Installed in the inner hole of the nozzle body, wherein the nozzle plate is fixed at the lower end of the inner hole of the nozzle body, and the center of the nozzle plate is coaxially provided with circular holes and tapered holes that communicate with each other. The round hole is on the top and the tapered hole is on the bottom; the valve seat is welded at the lower end of the inner hole of the nozzle body and its lower surface is in close contact with the upper surface of the nozzle plate; the steel ball is installed on the steel ball of the valve seat In the receiving hole and in sealing contact with and separated from the inner cone surface of the valve seat inner cone surface hole of the valve seat, the valve seat also includes a The surface hole is coaxially connected with the steel ball bearing hole, and the lower end of the valve stem is placed on the steel ball by spring force; it is characterized in that a number of oblique holes are arranged in the valve seat, The center of each inclined hole is eccentrically arranged relative to the central axis of the valve seat; several swirl grooves and a swirl hole are arranged on the lower surface of the valve seat, and the swirl hole is located on the center axis of the valve seat. The center position of the lower surface is coaxial with the round hole of the nozzle plate; the first end of each inclined hole communicates with the flow hole, and the first end of each swirl groove communicates with the second end of the corresponding inclined hole. The ends communicate with each other, and the second end of each swirl groove communicates with the swirl hole.

In a preferred embodiment of the present invention, the curve at one end of each swirl slot is connected to the corresponding inclined hole, and the curve at the other end of each swirl slot is tangent to the outer circle of the corresponding swirl hole.

In a preferred embodiment of the present invention, the number of the inclined holes is 3 to 5 and distributed uniformly around the centerline of the valve seat.

In a preferred embodiment of the present invention, the number of the swirl grooves is 3 to 5 and they are evenly distributed in the circumferential direction on the lower surface of the valve seat.

In a preferred embodiment of the present invention, the diameter of the swirl hole is larger than the diameter of the circular hole on the nozzle plate.

In a preferred embodiment of the present invention, the trajectory of each swirl tank consists of continuous curves.

In a preferred embodiment of the present invention, the groove width of each swirl groove is from wide to narrow or the same width from the inclined hole to the direction of the curved track of the swirl hole.

In a preferred embodiment of the present invention, the diameter of the flow hole should be greater than the sum of the diameters of each of the inclined holes

In a preferred embodiment of the present invention, the sum of the diameters of the inclined holes is more than 1.2 times the sum of the flow areas of the swirl grooves.

In a preferred embodiment of the present invention, the sum of the flow areas of the swirl grooves of the valve seat is more than 1.2 times the area of the round holes of the orifice plate

Due to the adoption of the above technical scheme, the present invention is provided with a plurality of inclined holes in the valve seat; the centers of the inclined holes are arranged eccentrically relative to the center line of the valve seat, so that the urea aqueous solution flowing out from the flow hole of the valve seat can produce a swirl effect, The first-stage swirl flow is formed at the front end of the spray.

In addition, there are multiple swirl grooves and a swirl hole on the lower surface of the valve seat; the trajectory of each swirl groove is composed of continuous curves; the curve at one end of each swirl groove is connected with the corresponding inclined hole, and each swirl groove The curve at the other end of the groove is tangent to the outer circle of the corresponding swirl hole, so that the aqueous urea solution flowing out of each inclined hole moves along the curved track of the corresponding swirl groove, causing severe impact and forming a turbulent flow that converges to the swirl hole In this way, a second-stage swirl flow is formed at the spray front end.

In addition, because the upper surface of the nozzle plate is closely attached to the lower surface of the valve seat; the nozzle hole on the nozzle plate adopts a stepped structure of a combination of round holes and tapered holes; the round holes set on the nozzle plate are used to precisely control the flow; The set cone hole is used to selectively adjust the spray angle and enhance the atomization effect.

Third, the steel ball is in sealing contact with and separated from the inner conical surface of the inner conical surface of the valve seat in the valve seat to close and open the flow hole in the valve seat; the urea aqueous solution coming from the flow hole passes through the inclined hole to form the first The first-stage swirl flow, the urea aqueous solution enters the swirl tank to form the second-stage swirl flow, which produces severe impact and forms a turbulent flow converging into the swirl hole, and then sprays out from the round hole of the nozzle plate. The urea aqueous solution is at the front end of the spray Continuous formation of two-stage swirl, the particle size of atomized particles will be significantly improved.

By adopting the above technical scheme, the two-stage swirl injector of the present invention has the advantages of being able to significantly increase the atomized particle size of the urea aqueous solution, improve flow consistency, simple and reasonable structure, convenient manufacture and assembly, and low production cost.

Description of drawings

Fig. 1 is a schematic general diagram of the structural injector of the present invention.

Fig. 2 is a schematic cross-sectional view of the valve seat of the present invention.

Fig. 3 is a structural schematic view of the lower surface of the valve seat of the present invention.

Fig. 4 is a schematic cross-sectional view of a nozzle plate of the present invention.

Fig. 5 is a schematic cross-sectional view of the valve stem of the present invention.

Fig. 6 is a schematic cross-sectional view of the iron core of the present invention

Detailed ways

Structure of the present invention, further concrete description is as follows in conjunction with accompanying drawing:

Referring to Figures 1 to 6, the two-stage swirl urea injector shown in the figures mainly includes an electromagnet component 12, an oil inlet joint, an iron core spring assembly and an injection valve assembly. The oil inlet joint includes a filter screen support 10, a filter screen 11 and an O-ring seal 9. A middle hole 1003 is arranged in the filter screen support 10 , and the filter screen 11 is placed in the middle hole 1003 .

The iron core spring assembly includes an iron core 8 , a spring upper seat 7 and a spring 6 .

The injection valve assembly includes a valve stem 5 , a nozzle body 4 , a steel ball 3 , a valve seat 2 , and a nozzle plate 1 .

The valve seat 2 is fixed at the lower end of the inner hole 402 of the nozzle body 4 by laser welding. Referring especially to Fig. 2 and Fig. 3, the valve seat 2 is sequentially provided with a steel ball bearing hole 201, an inner tapered surface hole 202 of the valve seat, a flow hole 203, an inclined hole 204, a swirl groove 208 and swirl holes 210 .

There are 3 to 5 oblique holes 204 on the valve seat, which are evenly distributed along the centerline 206 of the valve seat. The swirl effect can be produced, and the first-stage swirl is formed at the front end of the injection. The diameter of the flow hole 203 should be greater than the sum of the diameters of the inclined holes 204 .

At the bottom of the valve seat, there are 3 to 5 swirl grooves 208 evenly distributed around the circumference and a swirl hole 209. The trajectory of the swirl grooves is composed of

continuous curves

205 and 209. Connection, the curve 209 at the other end of the swirl groove is tangent to the outer circle of the swirl hole 210, from the inclined hole 204 to the direction of the curve track of the swirl hole 210, the width of the swirl groove is from wide to narrow or the same width, so that from the inclined hole 204 The outflowing urea aqueous solution moves along the curved track of the swirl groove 208, produces violent impact and forms a turbulent flow that converges into the swirl hole 210, thereby forming a second-stage swirl flow at the front end of the injection. The diameter of each inclined hole 204 is The sum is more than 1.2 times the sum of the flow areas of the swirl grooves 208 .

The upper surface 103 of the nozzle plate is in close contact with the lower surface 211 of the valve seat. The nozzle hole of the nozzle plate adopts a stepped structure of a combination of circular holes 101 and tapered holes 102. The thickness of the nozzle plate is 0.4-1.5mm. The circular hole 101 provided on the nozzle plate is used for precise flow control. The cone hole 102 set on the nozzle plate is used to selectively adjust the spray angle and enhance the atomization effect. The sum of the flow areas of the swirl grooves 208 on the lower surface of the valve seat is more than 1.2 times the area of the round hole 101 of the nozzle plate .

After adopting the above technical scheme, the urea aqueous solution coming from the overflow hole 203 of the valve seat 2 passes through the inclined hole 203 to form a first-stage swirl flow, and the urea aqueous solution enters the swirl groove 208 to form a second-stage swirl flow, resulting in severe impact And form a turbulent flow that converges into the swirl hole 210, and then sprays out from the nozzle hole 101 of the nozzle plate 1. The urea aqueous solution continuously forms a two-stage swirl at the front end of the injection, and the particle size of the atomized particles will be significantly increased.

The steel ball 3 is placed in the steel ball receiving hole 201 of the valve seat 2, and the steel ball 3 is symmetrically arranged with 3 to 5 flat squares 301 along the center, so that a fluid flow gap is formed between the steel ball 3 and the wall of the steel ball receiving hole 201 , for fluid passage.

The steel ball 3 is in sealing contact with and separated from the inner cone surface of the valve seat inner cone surface hole 202 in the valve seat 2 to close and open the flow hole 203 in the valve seat 2 .

The steel ball 3 is fixedly connected to the lower end of the valve stem 5 by welding, and the upper end of the nozzle body 4 is fixedly connected to the lower end of the iron core 8 .

Referring to Fig. 6, there is an axial inner hole which doubles as an oil passage in the iron core 8, and the axial inner hole is divided into three sections, from top to bottom respectively the first hole section 806, the second hole section 801, the second hole section The three-hole section 802 and the spring upper seat 7 are fitted in the first hole section 806 , and an oil hole 701 is arranged in the spring upper seat 7 . The spring 6 is arranged in the second hole segment 801 and the third hole segment 802 , the upper end of the spring 6 is against the upper spring seat 7 , and the lower end of the spring 6 is against the valve stem 5 . The inner diameter of the third hole section 802 is larger than the inner diameter of the second hole section 801 and the outer diameter of the spring 6 , which plays a role of vacating and avoids contact with the outer circle of the spring 6 .

The outer circle of the iron core 8 is composed of three pole sections, the first pole section 803, the second pole section 804 and the third pole section 805 are arranged coaxially from top to bottom, the first pole section 803 and the oil filter screen support The inner hole 1001 of 10 is guided and connected, the second rod section 804 cooperates with the second hole section 1201 of the electromagnet component 12 , and the third rod section 805 is guided and connected with the inner cavity 403 of the nozzle body 4 .

The iron core 8 is provided with two limit step surfaces, from top to bottom are the first limit step surface 807 and the second limit step surface 808, and the first limit step surface 807 is laser welded to the bottom of the oil filter bracket 10 The second stepped surface 808 is connected to the upper end surface of the nozzle body 4 by laser welding.

Referring to Fig. 5, the outer circle of the valve stem 5 is mainly composed of two-stage rod sections, which are respectively the first rod section 506 and the second rod section 502 from top to bottom. The first rod section is designed with an annular protrusion 507 and two The ring groove 505 is designed with a counterbore 509 in the middle, and the bottom surface of the counterbore 509 is designed with a groove 508 , and the second rod section 502 is provided with two horizontal holes 503 . The valve stem 5 is hollow and has a middle hole 504 , the top of the middle hole 504 communicates with the counterbore 509 , and the bottom surface of the middle hole 504 is provided with a tapered surface 501 . The axes of the two horizontal holes 503 cross each other on the projected plane and both pass through the middle hole 504 .

The valve stem 5 is installed in the nozzle body cavity 403 and the inner hole 401 of the nozzle body 4, wherein the first hole section 502 of the valve stem 5 is matched with the nozzle body cavity 403 of the nozzle body 4, and the second hole section 502 of the valve stem 5 is matched with the nozzle body cavity 403 of the nozzle body 4. An oil storage cavity 401 is formed between the inner holes 403 of the nozzle body 4 .

The electromagnet part 12 is provided with two sections of middle holes, from top to bottom are the first hole section 1201 and the second hole section 1202, the first hole section 1201 cooperates with the outer circle 1001 of the oil filter screen support 10, and simultaneously An O-ring seal 9 is arranged at the matching place of the net support 10 to prevent external water from entering and corroding. The second hole section 1202 cooperates with the second rod section 804 of the iron core 8 and the outer circle 404 of the nozzle body 4. At the same time, an O-ring 14 is arranged at the joint between the second hole section 1202 and the outer circle 404 of the nozzle body 4 to prevent External water enters and corrodes.

By setting the electromagnet part 12 on the outer circle 404 of the nozzle body 4 and/or the second rod section 804 outer wall of the iron core 8, the electromagnet part 12 drives the valve stem 5, and the nozzle body cavity 403 and the inner hole of the nozzle body 4 402 moves up and down repeatedly.

Working process and principle of the present invention are as follows:

As shown in Figures 1 to 6, the liquid is filtered by the filter screen 11, and then passes through the middle hole 1003 of the filter screen bracket 10, the oil hole 701 of the spring upper seat 7, the axial inner hole of the iron core 8, and the valve stem 5. The middle hole 504 and the two horizontal holes 503 enter into the oil storage chamber 401 between the second hole section 502 of the valve stem 5 and the inner hole 403 of the nozzle body 4, and then flow into the steel ball receiving hole 201 of the valve seat 2. The fluid flow gap between the hole wall and the steel ball flat 301.

When no power is applied, the force of the spring 6 on the valve stem 5 and the steel ball 3 is vertically downward, and the force of the hydraulic pressure on the valve stem 5 and the steel ball 4 is also vertically downward. Under the action of force, the inner cone surface in the valve seat inner cone surface hole 202 of the valve seat 2 is close to the inner cone surface and is in sealing contact. At this time, the flow hole 203 in the valve seat 2 is in a closed state.

When the electronic control unit energizes the electromagnet part 12 at an appropriate time, the iron core 8 quickly generates a sufficient electromagnetic attraction force, attracts the valve stem 5 and drives the steel ball 3 to overcome the spring force of the spring 6 and the hydraulic pressure to move upward rapidly. When the steel ball 3 is out of contact with the inner cone surface in the valve seat inner cone surface hole 202 of the valve seat 2, the flow hole 203 in the valve seat 2 is opened.

After the flow hole 203 in the valve seat 2 is opened, the urea aqueous solution passes through the inclined hole 203 to form a first-stage swirl flow, and the urea aqueous solution enters the swirl flow tank 208 to form a second-stage swirl flow, which produces a violent impact and forms a turbulent flow that converges to the In the swirl hole 210, it is sprayed out from the nozzle hole 101 of the nozzle plate 1.

When the fuel injection pulse width meets the requirements, the electromagnet component 12 is powered off under the instruction of the electronic control unit, and the electromagnetic force disappears. At this time, the valve stem 5 is also affected by the upward hydraulic pressure and the downward spring force. When the hydraulic pressure is less than the spring force, the valve stem 5 and the steel ball 3 start to move downward, and the spring force of the spring 6 is on the valve stem 5. During the downward movement, the hydraulic forces balance each other, and the resultant force at this time is only the downward spring force. The spring force of the spring 6 causes the valve rod 5 and the steel ball 3 to quickly fall back to the inner cone surface in the valve seat inner cone surface hole 202 of the valve seat 2, and at this time, the flow hole 203 in the valve seat 2 is in a closed state again, Spraying is over.

Claims

A two-stage swirl urea injector at least includes a nozzle body, a valve stem, a valve seat, a nozzle plate, and steel balls, the nozzle body has an inner hole, and the valve stem, valve seat, nozzle plate, and steel balls are all Installed in the inner hole of the nozzle body, wherein the nozzle plate is fixed at the lower end of the inner hole of the nozzle body, and the center of the nozzle plate is coaxially provided with circular holes and tapered holes that communicate with each other. The round hole is on the top and the tapered hole is on the bottom; the valve seat is welded at the lower end of the inner hole of the nozzle body and its lower surface is in close contact with the upper surface of the nozzle plate; the steel ball is installed on the steel ball of the valve seat In the receiving hole and in sealing contact with and separated from the inner cone surface of the valve seat inner cone surface hole of the valve seat, the valve seat also includes a The surface hole is coaxially connected with the steel ball bearing hole, and the lower end of the valve stem is placed on the steel ball by spring force; it is characterized in that a number of oblique holes are arranged in the valve seat, The center of each inclined hole is eccentrically arranged relative to the central axis of the valve seat; several swirl grooves and a swirl hole are arranged on the lower surface of the valve seat, and the swirl hole is located on the center axis of the valve seat. The center position of the lower surface is coaxial with the round hole of the nozzle plate; the first end of each inclined hole communicates with the flow hole, and the first end of each swirl groove communicates with the second end of the corresponding inclined hole. The ends communicate with each other, and the second end of each swirl groove communicates with the swirl hole.
A double-stage swirl urea injector according to claim 1, wherein the curve at one end of each swirl slot is connected to the corresponding inclined hole, and the curve at the other end of each swirl slot is connected to the corresponding swirl hole. Tangent to the outer circle.
The two-stage swirling urea injector according to claim 1, characterized in that, the number of the inclined holes is 3 to 5 and they are uniformly distributed around the center line of the valve seat.
The two-stage swirl urea injector according to claim 3, characterized in that, the number of the swirl grooves is 3 to 5 and they are evenly distributed in the circumferential direction on the lower surface of the valve seat.
The double-stage swirl urea injector according to claim 1, wherein the diameter of the swirl hole is larger than the diameter of the circular hole on the nozzle plate.
A two-stage swirl urea injector according to claim 1, characterized in that each swirl groove track is composed of continuous curves.
A two-stage swirl urea injector as claimed in claim 6, characterized in that, the groove width of each swirl groove is from the inclined hole to the direction of the curved track of the swirl hole, and the width is from wide to narrow or the same width.
The double-stage swirl urea injector according to claim 1, wherein the diameter of the flow hole should be greater than the sum of the diameters of the inclined holes.
The two-stage swirl urea injector according to claim 1, characterized in that the sum of the diameters of the inclined holes is more than 1.2 times the sum of the flow areas of the swirl grooves.
A two-stage swirl urea injector as claimed in claim 9, characterized in that the sum of the flow areas of the swirl grooves of the valve seat is more than 1.2 times the area of the round holes of the orifice plate .