CN211573660U - Venturi tube and exhaust gas recirculation system - Google Patents

Abstract

The application provides a venturi and exhaust gas recirculation system. The Venturi tube comprises a first connecting part, a contraction section, a throat part, a diffusion section and a second connecting part which are connected smoothly in sequence; still include the flow distribution plate, the flow distribution plate extends to the shrink section from first connecting portion. The Venturi tube can generate adsorption effect on the waste gas, and is favorable for the waste gas to rapidly pass through and effectively prevents gas from flowing back. The flow dividing plate effectively prevents the exhaust gases from different cylinders from colliding with each other, thereby reducing the loss of kinetic energy and velocity of the exhaust gases and further reducing the backflow of the exhaust gases. The first connecting part, the contraction section, the throat part, the diffusion section and the second connecting part which are connected smoothly can reduce the collision of the waste gas and the pipe wall, thereby reducing the loss of the kinetic energy and the speed of the waste gas. Thus, the venturi may introduce more exhaust gas into the cylinders of the engine to participate in combustion again. The exhaust gas recirculation system includes the above-described venturi.

Description

Venturi tube and exhaust gas recirculation system

Technical Field

The utility model relates to the technical field of engines, especially, relate to a venturi and exhaust gas recirculation system.

Background

Exhaust Gas Recirculation (EGR) systems are widely used in engines. The exhaust gas recirculation system cools and reintroduces tail gas which is exhausted by the engine and is rich in incombustible gas into a cylinder of the engine, so that the maximum combustion temperature of mixed gas in the cylinder is reduced, and the emission of nitrogen oxides is reduced. The engine comprises a plurality of cylinders which work and exhaust in turn.

Existing exhaust gas recirculation systems use a conduit connecting an air inlet of the exhaust gas recirculation system and a cooler of the exhaust gas recirculation system, the conduit providing a passage for the circulation of the exhaust gas.

However, under the working conditions of low rotating speed and low load of the engine, the pressure difference between the air inlet pressure and the exhaust pressure of the engine is small; the exhaust time interval of different cylinders is short, so that the exhaust gas from different cylinders collides with each other, the serious loss of the kinetic energy of the exhaust gas is caused, the flow speed of the exhaust gas is further reduced, and even the exhaust gas in a pipeline of an exhaust gas recirculation system flows back; existing exhaust gas recirculation systems are unable to introduce sufficient exhaust gas through existing conduits into the cylinders of the engine to again participate in combustion.

SUMMERY OF THE UTILITY MODEL

To the problem among the above-mentioned prior art, this application has proposed a venturi and exhaust gas recirculation system, and this exhaust gas recirculation system can utilize the venturi phenomenon to participate in burning again with the cylinder that sufficient waste gas introduced the engine under the operating mode of engine low-speed, low-load. The utility model provides a venturi is provided with the flow distribution plate in air inlet department, can avoid coming from the waste gas of different cylinders to collide each other effectively to reduce the loss of waste gas kinetic energy, speed. Simultaneously, the venturi pipe wall rounding off of this application is favorable to reducing the collision of waste gas and pipe wall, further reduces the loss of waste gas kinetic energy, speed, is favorable to participating in the burning again with the cylinder that more waste gas introduced the engine.

In a first aspect, the utility model provides a venturi tube, which comprises a first connecting part, a contraction section, a throat part, a diffusion section and a second connecting part which are connected smoothly in sequence; also included is a diverter plate extending from the first connection to the convergent section. By utilizing the adsorption effect of the Venturi tube, more exhaust gas can be introduced into a cylinder of the engine to participate in combustion again. Through the arrangement of the flow distribution plate, the mutual collision of the waste gases from different cylinders is effectively avoided, so that the loss of the kinetic energy and the speed of the waste gases is reduced, and the backflow of the waste gases is effectively reduced.

In one embodiment of the first aspect, the constriction comprises a first constriction, a second constriction and a third constriction smoothly connected in sequence and indented segment by segment. Through this embodiment, be favorable to reducing waste gas and pipe wall collision, reduce the loss of waste gas kinetic energy.

In one embodiment of the first aspect, the side edges of the diverter plate are fixedly attached to the inner wall of the venturi; the diverter plate bisects the first connection and extends from the first connection to the second constriction parallel to the exhaust gas flow direction. Through this embodiment, avoid coming from the waste gas of different cylinders through the side of flow distribution plate collision each other, cause the loss of waste gas kinetic energy to be favorable to introducing more waste gas into the cylinder of engine and participate in the burning again.

In one embodiment of the first aspect, a cross section taken through the first connection portion on a plane perpendicular to the axis of the venturi tube is a first cross section, a connecting surface taken through the first constriction and the second constriction is a second cross section, a connecting surface taken through the second constriction and the third constriction is a third cross section, a cross section taken through the throat portion on a plane is a fourth cross section, and a cross section taken through the second connection portion on a plane is a fifth cross section; the width of the first section, the width of the second section, the width of the third section, and the width of the fourth section are equal and between 38 and 42 millimeters; the width of the diffuser section gradually increases in a direction away from the first connection portion, so that the width of the fifth cross section is greater than the width of the fourth cross section, the fifth cross section is circular, and the diameter of the fifth cross section is between 45 and 50 millimeters. Through the embodiment, the area of the overflowing section of the diffusion section is gradually increased, the gas flow velocity is gradually reduced, and the gas is gradually diffused along the smooth pipe wall of the diffusion section.

In one embodiment of the first aspect, the width of the first section, the width of the second section, the width of the third section and the width of the fourth section are equal and 40 mm, and the diameter of the fifth section is 47.5 mm.

In one embodiment of the first aspect, the first section has a height of between 40 and 44 mm, the first constriction has a length of between 33 and 37 mm, the second section has a height of between 30 and 34 mm, the second constriction has a length of between 43 and 47 mm, the third section has a height of between 13 and 17 mm, and the third constriction has a length of between 23 and 27 mm. Through the embodiment, the impact of the waste gas with the pipe wall and the flow distribution plate is reduced, the absorption effect of the throat part is played, and therefore more waste gas is introduced into the cylinder of the engine to participate in combustion again.

In one embodiment of the first aspect, the first section has a height of 42 mm, the first constriction has a length of 35 mm, the second section has a height of 32 mm, the second constriction has a length of 45 mm, the third section has a height of 15 mm, and the third constriction has a length of 25 mm.

In one embodiment of the first aspect, the throat has a height of between 11 and 15 mm and a length of between 4.5 and 5.5 mm. Through the embodiment, smooth passing of the waste gas is facilitated, and the adsorption effect of the throat part is also facilitated, so that more waste gas is introduced into the cylinder of the engine to participate in combustion again.

In one embodiment of the first aspect, the throat has a height of 13 mm and a length of 5 mm.

In one embodiment of the first aspect, the diffuser segment has a length of between 145 and 155 millimeters. By the embodiment, the rapid reduction of the flow speed of the waste gas is favorably avoided, so that the gas is favorably diffused gradually along the smooth pipe wall of the diffusion section, and more waste gas is introduced into the cylinder of the engine to participate in combustion again; it is also advantageous to avoid waste of limited space.

In one embodiment of the first aspect, the diffuser segment has a length of 150 mm.

In a second aspect, the present invention further provides an exhaust gas recirculation system, including the above venturi tube; the first exhaust adapter pipe is connected with the first connecting part, and the second exhaust adapter pipe is connected with the second connecting part; the first exhaust adapter pipe is used for being communicated with an exhaust port of the engine, and the second exhaust adapter pipe is located on one side, close to the air inlet of the cylinder of the engine, of the Venturi pipe. By this embodiment, the exhaust gas recirculation system, due to the venturi described above, can introduce more exhaust gas into the cylinders of the engine to participate in combustion again. The arrangement of the Venturi tube flow distribution plate effectively avoids the mutual collision of the exhaust gases from different cylinders, thereby reducing the loss of kinetic energy and speed of the exhaust gases and further reducing the backflow of the exhaust gases. Meanwhile, the Venturi tube is smoothly connected with the first exhaust adapter tube with the rectangular overflowing section and the second exhaust adapter tube with the circular overflowing section, and the Venturi tube can be effectively applied without influencing the Venturi effect, so that enough waste gas is introduced into the cylinder of the engine to participate in combustion again.

The application provides a venturi and exhaust gas recirculation system compares in prior art, has following beneficial effect:

1. the flow distribution plate effectively avoids the mutual collision of the waste gases from different cylinders, thereby reducing the loss of kinetic energy and speed of the waste gases and reducing the backflow of the waste gases;

2. because the Venturi tube is provided with the contraction section with the gradually-reduced overflowing section, the throat part and the diffusion section with the gradually-increased overflowing section which are sequentially connected, the Venturi tube can generate an adsorption effect on waste gas, the waste gas can rapidly pass through the Venturi tube, and gas backflow is effectively prevented;

3. because the contraction section, the throat part and the diffusion section are smoothly connected, the collision of the waste gas and the pipe wall is favorably reduced, and the loss of the kinetic energy of the waste gas is reduced;

4. the venturi tube is smoothly connected with a first exhaust adapter tube with a rectangular-like overflowing section and a second exhaust adapter tube with a circular overflowing section.

The above-mentioned technical characteristics can be combined in various suitable ways or replaced by equivalent technical characteristics as long as the purpose of the invention can be achieved.

Drawings

The present invention will be described in more detail hereinafter based on embodiments and with reference to the accompanying drawings. Wherein:

FIG. 1 shows a schematic front view of a venturi according to an embodiment of the present invention;

FIG. 2 shows a schematic top view of a venturi according to an embodiment of the present invention;

fig. 3 shows a schematic cross-sectional view of various cross-sections of a venturi according to an embodiment of the present invention, wherein (a) is a schematic view of a first cross-section, (b) is a schematic view of a second cross-section, (c) is a schematic view of a third cross-section, (d) is a schematic view of a fourth cross-section, and (e) is a schematic view of a fifth cross-section;

fig. 4 shows an exploded view of an exhaust gas recirculation system according to an embodiment of the present invention.

Reference numerals:

1000-venturi tube;

1100-first connection;

1200-a constriction segment;

1210-a first constriction;

1220-a second constriction;

1230-third constriction;

1300-throat;

1400-a diffuser section;

1500-a second connection;

1600-splitter plate;

1710-a first cross section;

1720-a second cross-section;

1730-third section;

1740-fourth cross-section;

1750-fifth cross section;

2000-first exhaust transfer pipe;

3000-second exhaust adapter.

In the drawings, like parts are provided with like reference numerals. The drawings are not to scale.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

As shown in fig. 1 to 3, the present embodiment provides a venturi tube 1000 including a first connection part 1100, a contraction section 1200, a throat part 1300, a diffusion section 1400, and a second connection part 1500, which are smoothly connected in sequence; a diverter plate 1600 is also included, the diverter plate 1600 extending from the first connection 1100 to the retraction section 1200.

The exhaust gas discharged from the engine cylinder passes through the first exhaust adapter pipe 2000 and enters the second exhaust adapter pipe 3000 sequentially through the first connection part 1100, the contraction section 1200, the throat 1300, the diffusion section 1400 and the second connection part 1500 of the venturi tube 1000, and finally enters the cylinder of the engine after being processed, so that the maximum combustion temperature of the mixed gas in the cylinder is reduced, and the emission of nitrogen oxides is reduced.

The first connection 1100 of the venturi 1000 is used to connect to the first exhaust adapter 2000, and optionally, the first connection 1100 may be connected to the first exhaust adapter 2000 by a flange. In order to increase the sectional area of the exhaust port and improve the exhaust efficiency by using a limited space, the exhaust port of the engine is shaped like a rectangle.

Since the first exhaust transition pipe 2000 is connected to an exhaust port of the engine, the first exhaust transition pipe 2000 has a substantially rectangular shape in a cross section perpendicular to the flow direction of the exhaust gas, i.e., a flow cross section. In order to ensure that the first connection 1100 can be smoothly connected to the first exhaust gas transition pipe 2000, the flow cross section of the first connection 1100 has the same shape as the flow cross section of the first exhaust gas transition pipe 2000. Because the overflowing section is similar to a rectangle, a flange matched with the overflowing section in shape can be adopted for connection.

The converging section 1200, throat 1300 and diverging section 1400 of the venturi 1000, apply the venturi effect, introducing sufficient exhaust gas into the engine's cylinders to again participate in combustion. Specifically, as the exhaust gas passes through the constriction 1200, the area of the flow cross-section gradually decreases and the velocity of the exhaust gas gradually increases. As the exhaust gas passes through throat 1300, i.e., the narrowest point of venturi 1000, where the flow rate of the exhaust gas reaches a maximum and the pressure of the exhaust gas reaches a minimum, adsorption occurs to introduce more exhaust gas into the cylinders of the engine to participate in combustion again. When the exhaust gas passes through the diffuser section 1400 of the venturi tube 1000, since the cross-sectional area is gradually increased, the mutual collision of the exhaust gas can be reduced, so that the flow velocity of the exhaust gas is gradually reduced, the rapid decrease of the flow velocity of the exhaust gas is avoided, and the gradual diffusion of the gas along the smooth tube wall of the diffuser section 1400 is facilitated.

The venturi tube 1000 of the present embodiment has a contraction section 1200 with a gradually decreasing flow cross section, a throat 1300 and a diffusion section 1400 with a gradually increasing flow cross section, which is advantageous for exhaust gas to rapidly pass through the venturi tube 1000 and effectively prevent gas from flowing back.

The second connecting portion 1500 of the venturi 1000 is used for connecting with the second exhaust adapter 3000, and optionally, the second connecting portion 1500 may be connected with the second exhaust adapter 3000 through a flange or a clip. As shown in fig. 4, the second exhaust adapter tube 3000 is a U-shaped tube, and is used for bending and turning of the exhaust duct, and the circular flow cross section is compared with the rectangular flow cross section, so that the impact between the exhaust and the duct wall is reduced, and the loss of kinetic energy is reduced, and therefore the flow cross section of the second exhaust adapter tube 3000 is circular.

In order to ensure that the second connection part 1500 can be smoothly connected to the second exhaust adapter tube 3000, the flow cross section of the second connection part 1500 is the same as that of the first exhaust adapter tube 2000. Because the cross section of the overflowing part is circular, a flange or a clamp can be adopted for connection.

The venturi tube 1000 of the present embodiment is smoothly connected to the first exhaust adapter tube 2000 having a rectangular-like flow cross section and the second exhaust adapter tube 3000 having a circular flow cross section, and is effectively applied without affecting the venturi effect, so that sufficient exhaust gas is introduced into the cylinder of the engine to participate in combustion again.

The venturi 1000 of this embodiment further includes a flow distribution plate 1600, and the flow distribution plate 1600 is used to effectively prevent exhaust gases from different cylinders from colliding with each other, so as to reduce the loss of kinetic energy and velocity of the exhaust gases, and facilitate effective application of the venturi effect, so that sufficient exhaust gases are introduced into the cylinders of the engine to participate in combustion again.

The venturi tube 1000 of the present embodiment can absorb the exhaust gas, and is beneficial to the exhaust gas to pass through quickly and prevent the gas from flowing back effectively, and the flow distribution plate 1600 effectively avoids the exhaust gas from different cylinders from colliding with each other, thereby reducing the loss of kinetic energy and speed of the exhaust gas and further reducing the flow back of the exhaust gas, so as to introduce more exhaust gas into the cylinders of the engine to participate in combustion again; meanwhile, the venturi tube 1000 is smoothly connected to a first exhaust adapter tube 2000 having a rectangular-like flow cross section and a second exhaust adapter tube 3000 having a circular flow cross section.

As shown in fig. 1, the constriction 1200 of the present embodiment optionally includes a first constriction 1210, a second constriction 1220 and a third constriction 1230, which are smoothly connected and indented segment by segment in sequence.

The primary function of the first constriction 1210 is to adjust the flow direction of the exhaust gas such that the flow direction of the exhaust gas from the first exhaust transition pipe 2000 is gradually parallel to the axis of the venturi 1000. Too short length and too large slope of the first contraction section 1210 can cause the flow direction of the exhaust gas to be effectively adjusted, and then the exhaust gas collides with the pipe wall and the flow distribution plate 1600, so that kinetic energy is lost, and more exhaust gas is not favorably introduced into the cylinder of the engine to participate in combustion again. Too long and too small a slope of the first constriction 1210 will affect the adsorption of the throat 1300 and will not help to introduce more exhaust gas into the cylinder of the engine to participate in combustion again.

The second contraction section 1220 functions to merge exhaust gas from different cylinders. Too short a length and too large a slope of the second contraction section 1220 may cause the exhaust gases from different cylinders to collide with each other and lose kinetic energy of the exhaust gases, which is not favorable for introducing more exhaust gases into the cylinders of the engine to participate in combustion again. Too long and too small a slope of the second constriction 1220 will affect the adsorption of the throat 1300 and will not help to introduce more exhaust gas into the cylinder of the engine to participate in combustion again.

The main function of the third constriction 1230 is to smoothly guide the exhaust gases into the throat 1300. Too short a length and too large a slope of the third contracting section 1230 may cause the exhaust gas to collide with the pipe wall, and lose kinetic energy of the exhaust gas, which is not favorable for introducing more exhaust gas into the cylinder of the engine to participate in combustion again. Too long and too small a slope of the third constriction 1230 may affect the adsorption of the throat 1300 and may not facilitate the introduction of more exhaust gas into the cylinder of the engine to participate in combustion again.

The smooth connection of the first contraction section 1210, the second contraction section 1220 and the third contraction section 1230 is beneficial to reducing the collision of the exhaust gas with the pipe wall and reducing the loss of kinetic energy of the exhaust gas, thereby being beneficial to introducing more exhaust gas into the cylinder of the engine to participate in combustion again. The contraction section 1200 that retracts section by section is beneficial to firstly adjusting the flow direction of the exhaust gas to be parallel to the axis of the venturi tube 1000, then is beneficial to the confluence of the exhaust gas from different cylinders, and finally smoothly guides the exhaust gas into the throat 1300, so that the collision of the exhaust gas with the tube wall and the flow distribution plate 1600 is reduced, the backflow of the exhaust gas is reduced, and further, more exhaust gas is favorably introduced into the cylinders of the engine to participate in combustion again.

As shown in fig. 1 and 3, optionally, the side edge of the flow distribution plate 1600 of the present embodiment is fixedly connected with the inner wall of the venturi tube 1000; the diverter plate 1600 bisects the first connection 1100 and extends parallel to the exhaust gas flow direction from the first connection 1100 to the second constriction 1220.

When the engine is a six cylinder engine, the first chamber of the first exhaust transfer pipe 2000 receives exhaust gas from the first, second and third cylinders, and the second chamber of the first exhaust transfer pipe 2000 receives exhaust gas from the fourth, fifth and sixth cylinders. Since the time interval for exhausting the different cylinders is short, in order to prevent the exhaust gases from the different cylinders from colliding with each other, the first exhaust adapter 2000 is formed with a first chamber and a second chamber which are separated from each other.

The diverter plate 1600 bisects the first connection 1100 and extends from the first connection 1100 to the second constriction 1220 parallel to the exhaust gas flow direction, such that both sides of the diverter plate 1600 form a first flow chamber and a second flow chamber, which are symmetrically distributed with respect to the diverter plate 1600. The first flow chamber and the second flow chamber correspond to the two chambers of the first exhaust adapter 2000 one-to-one, so that the kinetic energy loss caused by mutual collision of the exhaust gases from different cylinders is effectively avoided.

The side edge of the flow distribution plate 1600 is fixedly connected with the inner wall of the venturi tube 1000, so that the first flow chamber and the second flow chamber are effectively isolated, and the loss of kinetic energy of the waste gas caused by mutual collision of the waste gas from different cylinders through the side edge of the flow distribution plate 1600 is avoided, thereby being beneficial to introducing more waste gas into the cylinders of the engine to participate in combustion again.

As shown in fig. 1 and fig. 2, optionally, in this embodiment, a section of the first connection portion 1100 taken on a plane perpendicular to the axis of the venturi tube 1000 is a first section 1710, a section of the first constriction 1210 taken on the plane and connected to the second constriction 1220 taken on the plane is a second section 1720, a section of the second constriction 1220 taken on the plane and connected to the third constriction 1230 taken on the plane is a third section 1730, a section of the throat 1300 taken on the plane is a fourth section 1740, and a section of the second connection portion 1500 taken on the plane is a fifth section 1750; the width of the first section 1710, the width of the second section 1720, the width of the third section 1730, and the width of the fourth section 1740 are equal and between 38 and 42 millimeters; in a direction away from the first connection 1100, the width of the diffuser section 1400 gradually increases such that the width of the fifth cross-section 1750 is greater than the width of the fourth cross-section 1740, the fifth cross-section 1750 being circular, the diameter of the fifth cross-section 1750 being between 45 and 50 millimeters.

The width of the first section 1710, the width of the second section 1720, the width of the third section 1730, and the width of the fourth section 1740 are equal to facilitate the fabrication process of the venturi 1000. The width of the fifth cross-section 1750 is greater than the width of the fourth cross-section 1740, which facilitates the gradual increase of the area of the flow cross-section of the diffuser 1400 and the gradual decrease of the gas flow velocity, and facilitates the gradual diffusion of the gas along the smooth tube wall of the diffuser 1400.

Preferably, the width of the first cross section 1710, the width of the second cross section 1720, the width of the third cross section 1730, and the width of the fourth cross section 1740 of this embodiment are equal and 40 mm, and the diameter of the fifth cross section 1750 is 47.5 mm.

Optionally, the first cross-section 1710 of this embodiment has a height between 40 and 44 mm, the first necked portion 1210 has a length between 33 and 37 mm, the second cross-section 1720 has a height between 30 and 34 mm, the second necked portion 1220 has a length between 43 and 47 mm, the third cross-section 1730 has a height between 13 and 17 mm, and the third necked portion 1230 has a length between 23 and 27 mm.

The first constriction 1210 connects the first and second cross-sections 1710, 1720, and as described above, the main function of the first constriction 1210 is to adjust the flow direction of the exhaust gas such that the flow direction of the exhaust gas from the first exhaust transition pipe 2000 becomes increasingly parallel to the axis of the venturi 1000. Too short length and too large slope of the first contraction section 1210 can cause the flow direction of the exhaust gas to be effectively adjusted, and then the exhaust gas collides with the pipe wall and the flow distribution plate 1600, so that kinetic energy is lost, and more exhaust gas is not favorably introduced into the cylinder of the engine to participate in combustion again. Too long and too small a slope of the first constriction 1210 will affect the adsorption of the throat 1300 and will not help to introduce more exhaust gas into the cylinder of the engine to participate in combustion again.

The second constriction 1220 connects the second cross-section 1720 and the third cross-section 1730. as described above, the second constriction 1220 functions to merge exhaust gases from different cylinders. Too short a length and too large a slope of the second contraction section 1220 may cause the exhaust gases from different cylinders to collide with each other and lose kinetic energy of the exhaust gases, which is not favorable for introducing more exhaust gases into the cylinders of the engine to participate in combustion again. Too long and too small a slope of the second constriction 1220 will affect the adsorption of the throat 1300 and will not help to introduce more exhaust gas into the cylinder of the engine to participate in combustion again.

The third constriction 1230 connects the third section 1730 and the fourth section 1740. as described above, the main function of the third constriction 1230 is to smoothly direct the exhaust gases into the throat 1300. Too short a length and too large a slope of the third contracting section 1230 may cause the exhaust gas to collide with the pipe wall, and lose kinetic energy of the exhaust gas, which is not favorable for introducing more exhaust gas into the cylinder of the engine to participate in combustion again. Too long and too small a slope of the third constriction 1230 may affect the adsorption of the throat 1300 and may not facilitate the introduction of more exhaust gas into the cylinder of the engine to participate in combustion again.

Preferably, the first cross section 1710 of this embodiment has a height of 42 mm, the first necked portion 1210 has a length of 35 mm, the second cross section 1720 has a height of 32 mm, the second necked portion 1220 has a length of 45 mm, the third cross section 1730 has a height of 15 mm, and the third necked portion 1230 has a length of 25 mm.

Optionally, the height of the throat 1300 of the present embodiment, i.e., the height of the fourth cross-section 1740, is between 11 and 15 millimeters, and the length of the throat 1300 is between 4.5 and 5.5 millimeters. The excessive height and length of the throat 1300 may result in insufficient flow velocity and insufficient pressure of the exhaust gas, thereby affecting the adsorption of the venturi 1000. Too small a throat 1300 height and too long a throat length are not conducive to smooth exhaust gas flow, and may also affect the adsorption of the venturi 1000. Preferably, the throat 1300 of the present embodiment has a height of 13 mm, and the throat 1300 has a length of 5 mm.

Optionally, the length of the diffuser segment 1400 of this embodiment is between 145 and 155 millimeters. Too small a length of the diffuser segment 1400 causes a rapid decrease in the exhaust flow rate, which is not conducive to gradual diffusion of the gas along the smooth wall of the diffuser segment 1400. The excessive length of the diffuser section 1400 wastes limited space and causes inconvenience to the installation and arrangement of the venturi 1000. Preferably, the diffuser section 1400 of the present embodiment is 150 millimeters in length.

As shown in fig. 4, the present embodiment also provides an exhaust gas recirculation system including the above-described venturi 1000; the exhaust gas recirculation system further comprises a first exhaust gas recirculation pipe 2000 connected with the first connecting part 1100 and a second exhaust gas recirculation pipe 3000 connected with the second connecting part 1500; the first exhaust adapter 2000 is used to communicate with an exhaust port of an engine, and the second exhaust adapter 3000 is located on one side of the venturi 1000 near an intake port of a cylinder of the engine.

As shown in fig. 4, the first exhaust adapter 2000 has a rectangular-like flow cross section, and the second exhaust adapter 3000 has a circular flow cross section.

The exhaust gas recirculation system, by virtue of having the venturi 1000 described above, may introduce more exhaust gas into the cylinders of the engine to participate in combustion again. The provision of the venturi 1000 flow distribution plate 1600 effectively avoids the exhaust gases from different cylinders from colliding with each other, thereby reducing the loss of kinetic energy, velocity of the exhaust gases and further reducing the backflow of the exhaust gases. Meanwhile, the venturi tube 1000 is smoothly connected to the first exhaust adapter 2000 having a rectangular-like flow cross section and the second exhaust adapter 3000 having a circular flow cross section, and is effectively applied without affecting the venturi effect, so that sufficient exhaust gas is introduced into the cylinder of the engine to participate in combustion again.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.

Claims (10)

1. A Venturi tube is characterized by comprising a first connecting part, a contraction section, a throat part, a diffusion section and a second connecting part which are connected smoothly in sequence; the device also comprises a flow distribution plate; the contraction section comprises a first contraction section, a second contraction section and a third contraction section which are smoothly connected in sequence and are retracted section by section; the side edge of the flow distribution plate is fixedly connected with the inner wall of the Venturi tube; the diverter plate bisects the first connection and extends from the first connection to the second constriction parallel to the exhaust gas flow direction.

2. The venturi tube of claim 1, wherein a cross-section taken through the first connection portion in a plane perpendicular to an axis of the venturi tube is a first cross-section, a plane taken through a connection surface of the first constriction and the second constriction is a second cross-section, a plane taken through a connection surface of the second constriction and the third constriction is a third cross-section, a plane taken through the throat is a fourth cross-section, and a plane taken through the second connection portion is a fifth cross-section;

the width of the first section, the width of the second section, the width of the third section, and the width of the fourth section are equal and between 38 and 42 millimeters; the width of the diffuser section gradually increases in a direction away from the first connection portion, so that the width of the fifth cross section is greater than the width of the fourth cross section, the fifth cross section is circular, and the diameter of the fifth cross section is between 45 and 50 millimeters.

3. The venturi of claim 2, wherein the width of the first section, the width of the second section, the width of the third section, the width of the fourth section are equal and 40 millimeters, and the diameter of the fifth section is 47.5 millimeters.

4. The venturi of claim 2, wherein the height of the first section is between 40 and 44 millimeters, the length of the first constriction is between 33 and 37 millimeters, the height of the second section is between 30 and 34 millimeters, the length of the second constriction is between 43 and 47 millimeters, the height of the third section is between 13 and 17 millimeters, and the length of the third constriction is between 23 and 27 millimeters.

5. The venturi of claim 4, wherein the first cross-section has a height of 42 mm, the first constriction has a length of 35 mm, the second cross-section has a height of 32 mm, the second constriction has a length of 45 mm, the third cross-section has a height of 15 mm, and the third constriction has a length of 25 mm.

6. The venturi of claim 2, wherein the throat has a height of between 11 and 15 millimeters and a length of between 4.5 and 5.5 millimeters.

7. The venturi of claim 6, wherein the throat has a height of 13 millimeters and a length of 5 millimeters.

8. The venturi of claim 2, wherein the length of the diffuser section is between 145 and 155 millimeters.

9. The venturi of claim 8, wherein the length of the diffuser section is 150 millimeters.

10. An exhaust gas recirculation system, comprising a venturi tube according to any one of claims 1-9; the first exhaust adapter pipe is connected with the first connecting part, and the second exhaust adapter pipe is connected with the second connecting part; the first exhaust adapter pipe is used for being communicated with an exhaust port of the engine, and the second exhaust adapter pipe is located on one side, close to the air inlet of the cylinder of the engine, of the Venturi pipe.

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