Double-bypass double-deflation structure for asymmetric runner supercharger

Abstract

The invention relates to a double-bypass double-deflation structure for an asymmetric runner supercharger. The volute comprises a volute body, the volute flow channel is arranged in the volute body and comprises a first volute flow channel and a second volute flow channel; the volute bypass flow channel is arranged in the volute body and comprises a first volute bypass flow channel and a second volute bypass flow channel, the first volute bypass flow channel is communicated with the first volute flow channel, and the second volute bypass flow channel is communicated with the second volute flow channel; the volute bypass flow channels corresponding to the volute flow channels can guide and rotate the airflow to a preset angle, and finally main flow gas is converged into the volute bypass flow channels. And each volute bypass flow channel is configured to enable the outlet speed of bypass gas flow to be greater than the speed of mainstream gas at the corresponding convergence position, and the included angle between the circumferential speed and the axial speed and the included angle between the circumferential speed and the axial speed of the corresponding mainstream gas are kept within a preset difference threshold value, so that an injection effect is generated in the convergence area. According to the invention, the overall efficiency of the turbine of the turbocharger is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of turbochargers, and in particular to a double bypass and double bleed structure for an asymmetric flow path supercharger. Background Art

[0002] A turbocharger can drive a turbine to do work through engine exhaust gas. The power output by the turbine drives a compressor impeller coaxial with it, enabling an internal combustion engine to obtain a greater intake pressure and making the power of the internal combustion engine stronger.

[0003] The volute of an asymmetric dual-flow turbocharger consists of two turbine flow paths with different cross-sectional areas. The large flow path is used to improve the pumping loss and fuel economy of the engine, and the small flow path is used to drive EGR (exhaust gas recirculation). The asymmetric flow path can be used to balance the nitrogen oxide emissions of the engine and effectively control the pumping loss.

[0004] In the prior art, a bypass passage exhaust gas bypass valve is mainly used to control the boost pressure. When the speed of the supercharger increases, the boost pressure also rises. Once it exceeds the set pressure, the exhaust gas bypass valve will open, and part of the exhaust gas will directly flow into the exhaust pipe from the bypass valve and merge with the gas flowing out of the turbine outlet. However, due to the different speeds and directions of these two gas flows, energy loss will inevitably occur during the merging process. Although some improvement schemes attempt to separate the bypass air flow from the main flow as much as possible, reducing the loss to a certain extent, the effect is still limited. Summary of the Invention

[0005] Therefore, the present invention provides a double bypass and double bleed structure for an asymmetric flow path supercharger, which adjusts the direction and speed of the bypass air flow to reach the optimal design state. At this time, the included angle between the circumferential speed and the axial speed of the bypass air flow is the same as that of the main flow speed, and the speed is greater than the main flow speed. This not only significantly reduces the loss during the merging of the air flows, but also uses the exhaust gas to increase the main flow speed, improving the overall efficiency of the turbine of the turbocharger and enabling the asymmetric flow path to exhibit better performance after the bypass valve is opened.

[0006] To solve the above technical problems, the present invention provides a double bypass and double bleed structure for an asymmetric flow path supercharger, including: A volute body; A volute flow path arranged inside the volute body, including a first volute flow path and a second volute flow path; A volute bypass flow path arranged inside the volute body, including a first volute bypass flow path and a second volute bypass flow path. The first volute bypass flow path is communicated with the first volute flow path, and the second volute bypass flow path is communicated with the second volute flow path; Wherein, the volute bypass flow path corresponding to each volute flow path can guide the air flow to rotate to a predetermined angle and finally merge into the main stream gas; Each of the volute bypass channels is configured such that the outlet velocity of the bypass air flow is greater than the velocity of the mainstream gas at the corresponding confluence position, and the angle between the circumferential velocity and the axial velocity is maintained within a preset difference threshold with respect to the angle between the circumferential velocity and the axial velocity of the corresponding mainstream gas, so as to generate an entrainment effect in the confluence zone.

[0007] In one embodiment of the present invention, the area of the key cross-section of the first volute channel is larger than the area of the key cross-section of the second volute channel.

[0008] In one embodiment of the present invention, a plane parallel to the volute inlet is defined as the 0° reference plane. The starting position of the first volute bypass channel covered in the circumferential direction of the volute is between 150° and 210°, and the ending position is between -30° and 30°.

[0009] In one embodiment of the present invention, a plane parallel to the volute inlet is defined as the 0° reference plane. The starting position of the second volute bypass channel covered in the circumferential direction of the volute is between -30° and 30°, and the ending position is between 150° and 210°.

[0010] In one embodiment of the present invention, the outlet velocity of the bypass air flow is 1.05 to 2.0 times the velocity of the mainstream air flow.

[0011] In one embodiment of the present invention, the difference threshold is between 0° and 1°.

[0012] The above technical solutions of the present invention have the following advantages compared with the prior art: For the double-bypass and double-bleed structure of the asymmetric flow channel supercharger described in the present invention, by adjusting the direction and velocity of the bypass air flow to reach the optimal design state, at this time, the angle between the circumferential velocity and the axial velocity is equal to that of the mainstream, and the velocity is greater than that of the mainstream. This not only reduces the loss during confluence but also increases the velocity of the mainstream by using the exhaust gas, improving the overall efficiency of the turbine of the turbocharger and enabling the asymmetric flow channel to have better performance after the bypass valve is opened.

[0013] The overall design of the present invention is simple and does not add additional components. The above functions can be achieved only through the structural design, which has good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to make the content of the present invention easier to be clearly understood, the following further describes the present invention in detail according to the specific embodiments of the present invention in conjunction with the drawings.

[0015] Figure 1 It is a schematic structural diagram of the volute body of the present invention.

[0016] Figure 2It is a schematic structural diagram of the distribution of the volute bypass flow channels on the volute body of the present invention.

[0017] Figure 3 It is a top view schematic diagram of the air flow of the first volute bypass flow channel of the present invention.

[0018] Figure 4 It is a top view schematic diagram of the air flow of the second volute bypass flow channel of the present invention.

[0019] Figure 5 It is a side view schematic diagram of the air flow of the second volute bypass flow channel of the present invention.

[0020] Figure 6 It is a schematic diagram of the flow channel distribution inside the volute body of the present invention.

[0021] Figure 7 It is a schematic diagram of the flow directions of the main stream gas and the bypass gas inside the volute body of the present invention.

[0022] Figure 8 It is a schematic diagram of the gas velocity components at the volute outlet of the present invention.

[0023] Figure 9 It is a schematic diagram of the coverage angle of the first volute bypass flow channel of the present invention.

[0024] Figure 10 It is a schematic diagram of the coverage angle of the second volute bypass flow channel of the present invention.

[0025] Explanation of the reference numerals in the drawings of the specification: 1. Volute body; 21. First volute flow channel; 22. Second volute flow channel; 31. First volute bypass flow channel; 32. Second volute bypass flow channel. Detailed implementation manners

[0026] The present invention will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0027] In the present invention, when directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, rather than indicating or implying that the technical features referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0028] In the present invention, the meaning of "several" is one or more, the meaning of "multiple" is two or more, and "greater than", "less than", "exceeding", etc. are understood not to include the present number; "above", "below", "within", etc. are understood to include the present number. In the description of the present invention, if there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0029] In the present invention, unless otherwise clearly defined, terms such as "arranged", "installed", "connected", etc. should be understood in a broad sense. For example, they can be directly connected, or indirectly connected through an intermediate medium; they can be fixedly connected, or detachably connected, or integrally formed; they can be mechanically connected, or electrically connected or capable of communicating with each other; they can be the communication inside two components or the interaction relationship between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in the present invention in combination with the specific content of the technical solution.

[0030] Referring to Figure 1 、 Figure 2 As shown, a double bypass and double bleed structure for an asymmetric flow path supercharger includes: A volute body 1; A volute flow path, arranged inside the volute body 1, including a first volute flow path 21 and a second volute flow path 22; A volute bypass flow path, arranged inside the volute body 1, including a first volute bypass flow path 31 and a second volute bypass flow path 32. The first volute bypass flow path 31 communicates with the first volute flow path 21, and the second volute bypass flow path 32 communicates with the second volute flow path 22; Wherein, the volute bypass flow path corresponding to each volute flow path can guide the airflow to rotate to a predetermined angle and finally merge into the mainstream gas.

[0031] Referring to Figures 3 to 8 As shown, each volute bypass flow path is configured such that the outlet velocity of the bypass airflow is greater than the velocity of the mainstream gas at the corresponding merging position, and the included angle between the circumferential velocity and the axial velocity is kept within a preset difference threshold with the included angle between the circumferential velocity and the axial velocity of the corresponding mainstream gas, so as to generate an entrainment effect in the merging area.

[0032] It can be understood that the entrainment effect is a phenomenon in fluid mechanics, which refers to the fact that a high-speed fluid entangles and drives the adjacent low-speed fluid to flow together through shear and induction effects, thereby realizing the transfer of energy or momentum.

[0033] Through the structural optimization of the bypass air flow, it has a higher speed at the outlet and is consistent or close in direction (the circumferential and axial velocity angles) with the mainstream air flow. When the high-speed bypass air flow enters the mainstream area, the mainstream air flow is entrained and accelerated through the shearing action of the high-speed air flow, so that the speed of the mainstream air flow is also increased, and the overall air flow kinetic energy is increased, thereby improving the flow efficiency at the turbine outlet.

[0034] Through the above settings, by optimizing the outlet speed and speed direction of the first volute bypass flow channel 31 and the second volute bypass flow channel 32, it is ensured that when the bypass air flow converges with the mainstream gas, the angles of its circumferential velocity and axial velocity are consistent or close with those of the mainstream gas, minimizing the shear layer and eddy current generated during the convergence of the two air flows, significantly reducing the energy loss, improving the transfer efficiency of the air flow kinetic energy, and further enhancing the overall working efficiency of the turbocharger, especially the turbine efficiency under the condition of the bypass valve opening.

[0035] In one embodiment, the area of the key cross-section of the first volute flow channel 21 is larger than the area of the key cross-section of the second volute flow channel 22. The first volute flow channel 21 (large flow channel) is used to effectively improve the pumping loss and fuel economy of the engine, and the second volute flow channel 22 (small flow channel) is used to drive the (EGR) exhaust gas recirculation.

[0036] It can be understood that the key cross-section refers to the important flow channel cross-sectional area that affects the air flow performance, and this cross-section directly determines the key parameters such as the flow rate, speed, and pressure of the air flow. Such as the narrowest part, the turning part, or the air flow convergence / separation part of the flow channel.

[0037] Due to the adoption of the double bypass and double bleed structure, the large and small flow channels respectively correspond to two different bleed flow channels, namely the first volute bypass flow channel 31 and the second volute bypass flow channel 32. The first volute bypass flow channel 31 guides the air flow to rotate by a certain angle, controls the angle between the circumferential and radial velocities to be equal to the angles of the circumferential and radial velocities of the mainstream gas at the confluence position, and finally converges into the mainstream gas. The second volute bypass flow channel 32 also guides the air flow to rotate by a certain angle, controls the angle between the circumferential and radial velocities to be equal to the angles of the circumferential and radial velocities of the mainstream gas at the confluence position, and finally converges into the mainstream gas.

[0038] In one embodiment, by establishing a three-dimensional model of the volute and the bypass flow channel and performing CFD simulation calculations, the velocity conditions of the air flow at the turbine outlet are calculated, including the absolute value of the velocity and the components of the circumferential velocity and the axial velocity. The included angle between the circumferential velocity and the axial velocity of the mainstream gas at the outlet position of the volute bypass flow channel is calculated. By designing and adjusting the outlet coverage position angle and width of the volute bypass flow channel, the respective outlet widths B1 and B2 of the first volute flow channel 21 and the second volute flow channel 22 are obtained. The outlet velocity of the bypass air flow is made greater than that of the mainstream fluid, and the included angle between the circumferential velocity and the axial velocity is equal to or close to the included angle between the circumferential velocity and the axial velocity of the mainstream gas (the difference threshold is within 0 to 1°), thereby forming an entrainment effect.

[0039] Specifically, referring to Figure 9 、 Figure 10 As shown, the plane parallel to the volute inlet is defined as the 0° reference plane. The starting position of the first volute bypass flow channel 31 covered in the circumferential direction of the volute is between 150° and 210°, and the ending position is between -30° and 30°. The first volute bypass flow channel 31 finally merges into the mainstream gas after rotation. The coverage angle of the first volute bypass flow channel 31 is from a° to b°, where a ∈ (150°, 210°) and b ∈ (-30°, 30°). The starting position of the second volute bypass flow channel 32 covered in the circumferential direction of the volute is between -30° and 30°, and the ending position is between 150° and 210°. The second volute bypass flow channel 32 merges into the mainstream gas after rotation. The coverage angle of the second volute bypass flow channel 32 is from c° to d°. c ∈ (-30°, 30°) and b ∈ (150°, 210°).

[0040] According to the CFD simulation results, the coverage angle ranges of the first volute bypass flow channel 31 and the second volute bypass flow channel 32 are reasonably set to ensure that there is sufficient rotation path for the bypass air flow to adjust the velocity direction before confluence, ensure smooth air flow guidance, and the cross-sectional area of the bypass flow channel changes monotonically with the bypass air flow, avoiding local backflow or pressure drop loss caused by unreasonable flow channel settings.

[0041] In one embodiment, the outlet velocity of the bypass air flow is 1.05 to 2.0 times the velocity of the mainstream air flow. The outlet velocity of the bypass air flow is designed to be greater than the velocity of the mainstream gas (1.05 to 2.0 times that), generating an entrainment effect in the confluence area. The high-speed bypass air flow drives the mainstream gas to accelerate and increases the kinetic energy of the mainstream gas. This design not only improves the overall velocity field of the air flow but also improves the exhaust pulsation characteristics of the engine and optimizes the responsiveness and fuel economy of the engine under high-load conditions.

[0042] The bypass flow passage of the turbine housing can eliminate the negative impact of the bypass airflow on the main flow and at the same time make the bypass airflow have a positive impact on the main flow, make good use of the unused energy in the bypass airflow, and improve the efficiency of the turbine under the condition of the bypass valve opening.

[0043] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A double bypass double bleed structure for an asymmetric flow channel supercharger, characterized in that: include: Volute body (1); A volute flow channel, arranged in the volute body (1), comprising a first volute flow channel (21) and a second volute flow channel (22); a volute bypass flow channel, arranged in the volute body (1), comprising a first volute bypass flow channel (31) and a second volute bypass flow channel (32), wherein the first volute bypass flow channel (31) is connected to the first volute flow channel (21), and the second volute bypass flow channel (32) is connected to the second volute flow channel (22); Wherein, the volute bypass flow channel corresponding to each volute flow channel can guide the airflow to rotate to a predetermined angle and finally merge into the mainstream gas; Each of the volute bypass flow channels is configured to make the outlet velocity of the bypass airflow greater than the mainstream gas velocity at the corresponding confluence position, and the angle between the circumferential velocity and the axial velocity and the angle between the circumferential velocity and the axial velocity of the corresponding mainstream gas are maintained within a preset difference threshold to produce an ejection effect in the confluence area.

2. The double bypass double bleed structure for an asymmetric flow channel supercharger according to claim 1, characterized in that: The area of ​​the critical cross section of the first volute flow passage (21) is greater than the area of ​​the critical cross section of the second volute flow passage (22).

3. The double bypass double bleed structure for an asymmetric flow channel supercharger according to claim 1, characterized in that: A surface parallel to the volute inlet is defined as a 0° reference surface, and the first volute bypass flow channel (31) covers a starting position of 150° to 210° in the volute circumferential direction, and an end position of -30° to 30°.

4. The double bypass double bleed structure for an asymmetric flow channel supercharger according to claim 1, characterized in that: A surface parallel to the volute inlet is defined as a 0° reference surface, and the second volute bypass flow channel (32) covers a starting position of -30° to 30° in the volute circumferential direction, and an end position of 150° to 210°.

5. The double bypass double bleed structure for an asymmetric flow channel supercharger according to claim 1, characterized in that: The outlet velocity of the bypass airflow is 1.05 to 2.0 times the velocity of the mainstream airflow.

6. The double bypass double bleed structure for an asymmetric flow channel supercharger according to claim 1, characterized in that: The difference threshold is between 0 and 1°.

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