A two-stage back pressure adjustment mechanism

Abstract

This invention relates to a two-stage back pressure regulating mechanism, comprising a throttle pipe (1), a small throttle valve (3), a large throttle valve (4), a large throttle valve shaft (7), a bend (8), a flange bushing (10), a sealing bushing (13), and a small throttle valve shaft (17). By rotating the large throttle valve shaft and the small throttle valve shaft, the different positions of the large and small throttle valves within the conical surface of the throttle pipe can be adjusted and locked to achieve the required back pressure, thereby realizing the adjustment of the exhaust back pressure of the test engine or test mechanism without the need for complex adjustments to the exhaust pipeline. It features simple processing, quick installation, high adjustment efficiency, and convenient fault handling, significantly reducing the economic and time costs of product development in engine testing and component testing.

Description

Technical Field

[0001] This invention belongs to the field of engine and component testing technology, and specifically relates to a two-stage back pressure adjustment mechanism. Background Technology

[0002] The test engine differs from the target engine in structure and test conditions. Due to its unique structure, it is difficult for the test engine to achieve complete consistency with the performance of the target engine, especially in the intake and exhaust systems. To more realistically simulate the exhaust resistance generated by the turbocharger, EGR and other units connected to the exhaust pipe of the target engine, the test engine is often designed with a back pressure adjustment device after the exhaust pipe. By adjusting the back pressure adjustment device, the exhaust pressure of the test engine is made consistent with that of the target engine, thereby achieving consistency between the performance of the test engine and the target engine.

[0003] An existing low-pressure simulation test bench for internal combustion engine characteristics comprises an intake simulation device, an exhaust back pressure regulating device, an atmospheric back pressure regulating device within the engine crankcase, and a low-pressure starting device simulating a high-altitude environment. The exhaust back pressure regulating device consists of an exhaust pressure stabilizing cylinder, a vacuum device connected to it via a pipeline, and an exhaust pressure regulating valve installed on the pipeline. The low-pressure test bench can simulate atmospheric pressure at different altitudes. However, the exhaust back pressure regulating device disclosed in the aforementioned prior art suffers from technical problems such as slow exhaust back pressure adjustment and difficulty in accurately controlling the exhaust back pressure. Summary of the Invention

[0004] This invention provides a two-stage back pressure adjustment mechanism, which aims to solve the problem of adjusting the back pressure of the test engine and related test exhaust according to the target resistance.

[0005] To solve the above technical problems, the present invention provides a two-stage back pressure regulating mechanism, characterized in that: it includes a throttling pipe (1), a small throttling valve (3), a large throttling valve (4), a large throttling valve shaft (7), a bend (8), a flange bushing (10), a sealing bushing (13), and a small throttling valve shaft (17); the inner cavity of the throttling pipe (1) is composed of a cylindrical pipe and a tapered throttling pipe, the rear end of the tapered throttling pipe of the throttling pipe (1) is fixedly connected to the front end of the bend (8), the bend (8) is an intermediate connecting pipe with a pipe diameter of 90°, the bottom end of the bend is used to connect to the exhaust pipe of the test chamber, and the sealing bushing (13) is set on the flange. The bushing is fixedly connected to the flange bushing; the flange bushing passes through the outer wall of the bend (8) and is fixed; the large throttle valve shaft (7) is a hollow cylindrical structure, one end passes through the sealing bushing (13) and is fixed, and the other end is fixedly connected to the large throttle valve (4); one end of the small throttle valve shaft (17) passes through the center hole of the large throttle valve shaft (7) and is fixed, and the other end is fixedly connected to the small throttle valve (3) set in the throttle pipe (1); during the test, by adjusting the position of the large throttle valve shaft 7 and the small throttle valve shaft 17, the position adjustment of the large throttle valve 4 and the small throttle valve 3 in the throttle pipe 1 is realized, thereby realizing the accurate measurement of the exhaust back pressure.

[0006] Beneficial effects: This invention achieves the adjustment and locking of the required back pressure by rotating the large throttle valve shaft and the small throttle valve shaft, thereby adjusting the different positions of the large and small throttle valves within the cone surface of the throttle tube. This allows for the adjustment of the exhaust back pressure of the test engine or test mechanism without the need for complex adjustments to the exhaust pipe. It features simple processing, quick installation, high adjustment efficiency, and convenient troubleshooting, significantly reducing the economic and time costs of product development in engine and component testing. Attached Figure Description

[0007] Figure 1 This is a cross-sectional view of a two-stage back pressure adjustment mechanism according to the present invention;

[0008] Figure 2 This is a schematic diagram of a two-stage back pressure adjustment mechanism according to the present invention;

[0009] Figure 3 This is a schematic diagram of a throttling tube for a two-stage back pressure regulating mechanism according to the present invention;

[0010] Figure 4 This is a cross-sectional view of the throttling tube of a two-stage back pressure regulating mechanism according to the present invention;

[0011] Figure 5 This is a schematic diagram of a bend in a two-stage back pressure adjustment mechanism according to the present invention;

[0012] Figure 6 This is a cross-sectional view of a bent pipe of a two-stage back pressure adjustment mechanism according to the present invention;

[0013] Figure 7 This is a schematic diagram of a small throttle valve in a two-stage back pressure regulating mechanism according to the present invention;

[0014] Figure 8 This is a cross-sectional view of a small throttle valve in a two-stage back pressure regulating mechanism according to the present invention;

[0015] Figure 9 This is a schematic diagram of a large throttle valve in a two-stage back pressure regulating mechanism according to the present invention;

[0016] Figure 10 This is a cross-sectional view of a large throttle valve in a two-stage back pressure regulating mechanism according to the present invention.

[0017] Figure 11 This is a schematic diagram of the large throttle valve shaft of a two-stage back pressure regulating mechanism according to the present invention;

[0018] Figure 12 This is a cross-sectional view of the large throttle valve of a two-stage back pressure regulating mechanism according to the present invention;

[0019] Figure 13 This is a schematic diagram of a flange bushing for a two-stage back pressure regulating mechanism according to the present invention;

[0020] Figure 14 This is a cross-sectional view of a flange bushing of a two-stage back pressure regulating mechanism according to the present invention;

[0021] Figure 15 This is a schematic diagram of the small throttle valve shaft of a two-stage back pressure regulating mechanism according to the present invention;

[0022] Figure 16 This is a schematic diagram of a sealing bushing for a two-stage back pressure adjustment mechanism according to the present invention;

[0023] Figure 17 This is a cross-sectional view of a sealing bushing of a two-stage back pressure regulating mechanism according to the present invention;

[0024] Figure 18 This is a schematic diagram of a sealing gasket for a two-stage back pressure adjustment mechanism according to the present invention;

[0025] Figure 19 This is a schematic diagram of a flange bushing nut for a two-stage back pressure regulating mechanism according to the present invention;

[0026] Figure 20 This invention relates to a copper washer II for a two-stage back pressure adjustment mechanism.

[0027] Figure 21 This invention relates to a locking nut II for a two-stage back pressure adjustment mechanism.

[0028] Figure 22This invention relates to a locking nut I for a two-stage back pressure adjustment mechanism.

[0029] Figure 23 The copper washer I is a two-stage back pressure adjustment mechanism as described in this invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1-Throttle tube; 2-Locking nut I; 3-Small throttle valve; 4-Large throttle valve; 5-M10 standard bolt; 6-M10 standard nut; 7-Large throttle valve shaft; 8-Bend; 9-Flange bushing nut; 10-Flange bushing; 11-M8 standard bolt; 12-Locking nut II; 13-Sealing bushing; 14-Copper washer II; 15-Sealing gasket; 16-Copper washer I; 17-Small throttle valve shaft. Detailed Implementation

[0032] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below.

[0033] This invention proposes a two-stage back pressure regulating mechanism, comprising a throttling pipe 1, a locking nut I (2), a small throttling valve 3, a large throttling valve 4, an M10 standard bolt 5, an M10 standard nut 6, a large throttling valve shaft 7, a bend 8, a flange bushing nut 9, a flange bushing 10, an M8 standard bolt 11, a locking nut II (12), a sealing bushing 13, a copper washer II (14), a sealing gasket 15, a copper washer I (16), and a small throttling valve shaft 17. The throttling pipe 1 is made of heat-resistant ferrosilicon cast iron, and has two horizontal large and small flanges at its front and rear ends. The small flange has a raised stop, and the flange has a mounting connection through hole. The large flange has a raised stop 6, the size of which matches the recessed stop of the flange on the end face of the bend 8, and the flange has a mounting connection through hole. The inner cavity of the throttling tube 1 is composed of a cylindrical tube and a tapered throttling tube. The inner cavity of the tapered throttling tube has an included angle of 30°. Three measuring point interfaces are arranged in the circumferential direction of the outer periphery of the cylindrical tube. Each measuring point is spaced 60° apart. The threads of the measuring point interfaces are matched with the threads of temperature, pressure and other sensors.

[0034] The elbow 8 is an intermediate connecting pipe with a 90° connection. It has two connecting flanges on its two vertical end faces. The end face flange connects to the throttling pipe 1. The end face flange has a recessed stop, the depth of which is 0.15mm greater than the sum of the flange stop boss height and the sealing gasket thickness. The flange has a through hole for installation. The elbow 8 has a threaded support port with a thread specification matching the flange bushing thread of the flange bushing 10. The central axis is coaxial with the center of the end face flange. The bottom flange is used to connect to the exhaust pipe of the laboratory. The end face flange has a recessed stop and a through hole for installation.

[0035] The flange bushing 10 is provided with a locking threaded flange, the thread hole specification on the flange matches the locking hole on the sealing bushing, the flange bushing boss is provided with a flange bushing thread, the thread specification matches the thread support port thread on the bend diameter, and the inner diameter of the flange bushing matches the outer diameter of the sealing bushing 13.

[0036] The sealing bushing 13 is provided with a sealing bushing flange, and the locking hole on the flange matches the threaded hole on the flange of the flange bushing 10. The internal threaded hole specification of the sealing bushing 13 matches the long thread on the end face of the large throttle valve shaft 7.

[0037] The large throttle valve shaft 7 is a hollow cylindrical structure. One end is provided with a hexagonal fastening surface and a long end thread. The specifications of the long end thread match the internal thread hole of the sealing bushing 13. The other end is provided with two parallel locking planes and a bottom locking thread. The specifications of the thread match the internal thread of the large throttle valve 4. One end of the long hole in the large throttle valve shaft 7 is provided with an internal thread. The specifications of the thread match the external thread of the small throttle valve shaft 17. The end face of the other end of the long hole is a sealing bottom surface. This surface is pressed and fitted against the copper washer I (16) inside the large throttle valve 4.

[0038] One end of the small throttle valve shaft 17 is provided with a small throttle valve hexagon and a small throttle valve external thread, the thread specification of which matches the internal thread of the large throttle valve shaft 7. The other end is provided with two parallel small throttle valve fastening planes and a small throttle valve end face thread, the thread of which matches the internal thread hole of the boss of the small throttle valve 3.

[0039] The large throttle valve 4 is a cone-shaped frustum with a cone angle of 60°. It has an internal thread that matches the locking thread on the bottom surface of the large throttle valve shaft 7. The inner diameter of the large throttle valve 4 matches the outer diameter of the small throttle valve shaft 17. The large throttle valve 4 has a boss end face that is a locking cover. This face is pressed and fitted with the locking nut II (12). The other end face of the internal thread of the large throttle valve is the sealing surface of the large throttle valve. This sealing surface is pressed and fitted with the copper washer II (14).

[0040] The small throttle valve 3 has a front spherical throttle surface and a rear conical throttle surface boss structure. The radius of the sphere is R30 and the included angle of the tail cone is 64°. The small throttle valve 3 has a boss with an internal threaded hole. The specifications of the threaded hole match the small throttle valve end face thread of the small throttle valve shaft 17. The sealing end face of the boss is pressed and fitted with the locking nut I (2).

[0041] The installation method of this invention is as follows:

[0042] First, screw the flange bushing nut 9 onto the flange bushing thread of the flange bushing 10, screwing it into the root of the thread. Then, screw the flange bushing 10 with the bushing nut 9 into the threaded support port of the bend pipe 8, rotating it until the gap from the bushing nut 9 is 5mm. Then, use the corresponding wrench to unscrew the bushing nut 9 in the opposite direction until it fits and is pressed against the end face of the threaded support port of the bend pipe 8.

[0043] Subsequently, copper gasket II is inserted into the inner hole of the installed flange bushing 10. Using a long-handled tool, it is gently pushed until it contacts the sealing bottom surface of the inner hole. Then, sealing bushing 13 is inserted into the inner hole of flange bushing 10. Sealing bushing 13 is pushed until the bottom sealing surface of sealing bushing is in close contact with copper gasket II. The sealing bushing flange of sealing bushing 13 is rotated so that its locking hole corresponds to the threaded hole on the locking threaded flange of flange bushing 10. Sealing bushing 13 and flange bushing 10 are tightened with four M8 standard bolts. The torque is measured with a torque wrench and is 30 Nm.

[0044] Then, place the copper washer I onto the sealing surface of the large throttle valve 4, and then screw the bottom locking thread of the large throttle valve shaft 7 into the internal thread of the large throttle valve 4 until the bottom surface of the large throttle valve shaft 7 contacts the copper washer I. Use a wrench to lock the locking plane of the large throttle valve shaft 7, and at the same time turn the large throttle valve 4 to press the bottom surface of the large throttle valve shaft 7 tightly against the copper washer.

[0045] Insert the large throttle valve shaft 7 component, which has been installed in the above steps, into the bottom hole of the installed flange bushing 10 in the reverse direction, and then through the bottom hole of the installed sealing bushing 13 until the long thread on the end face of the large throttle valve shaft 7 contacts the internal thread hole of the sealing bushing 13. Rotate the large throttle valve shaft 7 component to rotate it out of the flange end face of the sealing bushing 13. Then screw the flange bushing nut 9 into the long thread on the end face of the large throttle valve shaft 7 that protrudes from the flange of the sealing bushing 13. Screw the bushing nut 9 close to the hexagonal fastening surface. Then use a wrench to turn the hexagonal fastening surface of the large throttle valve shaft 7 component until the sealing surface of the bushing nut 9 is 10mm away from the sealing surface of the threaded support port of the bend 8. Keep the wrench in place and fix the large throttle valve shaft 7. Use the wrench to turn the bushing nut 9 out in the reverse direction until it is pressed tightly against the sealing surface of the threaded support port of the bend 8.

[0046] Subsequently, screw the locking nut I onto the threaded end face of the small throttle valve on the small throttle valve shaft 17, bringing it close to the fastening plane of the small throttle valve. Then, screw the internal threaded hole of the boss of the small throttle valve 3 into the threaded hole on the end face of the small throttle valve on the small throttle valve shaft 17. Use a wrench to tighten the small throttle valve on the fastening plane of the small throttle valve on the small throttle valve shaft 17, and turn the small throttle valve 3 to press it tightly against the small throttle valve shaft 17. Keeping the wrench fixed on the small throttle valve shaft 17, use the wrench to unscrew the locking nut I in the opposite direction, pressing it tightly against the sealing end face of the boss of the small throttle valve 3. Insert the installed small throttle valve shaft 17 into the large throttle valve shaft 7, inserting it from the sealing bottom surface of the large throttle valve shaft 7 until the external thread of the small throttle valve shaft 17 contacts the internal thread hole of the sealing bushing 13. Move the small throttle valve shaft 17 to unscrew the flange end face of the sealing bushing 13. Screw the lock nut I into the small throttle valve external thread protruding from the flange end face of the small throttle valve shaft 17. Use a wrench to press the end face of the lock nut I tightly against the hexagonal fastening end face of the large throttle valve shaft 7.

[0047] Place the sealing gasket 15 into the recessed stop of the installed bend 8. Then, insert the boss stop on the large flange side of the throttle tube 1 into the recessed stop of the bend 8. Rotate the throttle tube 1 so that the light hole on its large flange is aligned with the light hole on the end flange of the bend 8. At the same time, make sure to rotate the three measuring points on the cylindrical tube of the throttle tube 1 to the top. Finally, use six M10 standard bolts and M10 standard nuts to connect the bend 8 component and the throttle tube 1 and press them tightly together. This completes the installation of a two-stage back pressure regulating mechanism.

[0048] During the test, the exhaust pressure was measured through the exhaust pipe. If it is necessary to increase or decrease the exhaust back pressure, simply loosen the bushing nut 9 and the locking nut I with a wrench, adjust the position of the large throttle valve shaft 7 and the small throttle valve shaft 17, and adjust the position of the large throttle valve 4 and the small throttle valve 3 in the throttle pipe 1, thereby achieving accurate measurement of the exhaust back pressure (clockwise rotation increases the back pressure, counterclockwise rotation decreases the back pressure).

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A two-stage back pressure adjustment mechanism, characterized in that: The system includes a throttling pipe (1), a small throttling valve (3), a large throttling valve (4), a large throttling valve shaft (7), a bend (8), a flange bushing (10), a sealing bushing (13), and a small throttling valve shaft (17). The inner cavity of the throttling pipe (1) is composed of a cylindrical pipe and a tapered throttling pipe. The rear end of the tapered throttling pipe of the throttling pipe (1) is fixedly connected to the front end of the bend (8). The bend (8) is an intermediate connecting pipe with a pipe diameter of 90°. The bottom end of the bend is used to connect to the exhaust pipe of the laboratory. The sealing bushing (13) is set inside the flange bushing and fixedly connected to the flange bushing. The flange bushing passes through the bend. (8) The outer wall is fixed. The large throttle valve shaft (7) is a hollow cylindrical structure. One end passes through the sealing bushing (13) and is fixed. The other end is fixedly connected to the large throttle valve (4). One end of the small throttle valve shaft (17) passes through the center hole of the large throttle valve shaft (7) and is fixed. The other end is fixedly connected to the small throttle valve (3) set in the throttle tube (1). During the test, by adjusting the position of the large throttle valve shaft (7) and the small throttle valve shaft (17), the position of the large throttle valve (4) and the small throttle valve (3) in the throttle tube (1) can be adjusted, thereby realizing the accurate measurement of exhaust back pressure.

2. The two-stage back pressure adjustment mechanism according to claim 1, characterized in that: The elbow (8) has two connecting flanges on its two vertical end faces. The end face flange is connected to the throttle pipe (1). The end face flange has a concave stop. The tolerance is H7, which matches the stop of the large flange of the throttle pipe. The depth of the concave stop is 0.15mm greater than the sum of the height of the large flange stop and the thickness of the sealing gasket. The flange has a through hole for installation and connection.

3. The two-stage back pressure adjustment mechanism according to claim 2, characterized in that: The bend (8) is provided with a threaded support port on the pipe diameter. Its thread specification matches the flange bushing thread of the flange bushing (10). The center axis is designed to be coaxial with the center of the end face flange.

4. The two-stage back pressure adjustment mechanism according to claim 2, characterized in that: The flange bushing (10) is provided with a locking threaded flange. The threaded hole on the flange matches the locking hole on the sealing bushing. The flange bushing boss is provided with a flange bushing thread. The thread specification matches the thread support thread on the bend diameter of the pipe. The inner diameter of the flange bushing matches the outer diameter of the sealing bushing (13). A clearance fit with a clearance of 0.2mm is adopted.

5. The dual-stage back pressure adjustment mechanism according to claim 3, characterized in that: The sealing bushing (13) is provided with a sealing bushing flange. The locking hole on the flange matches the threaded hole on the flange of the flange bushing (10). The internal threaded hole of the sealing bushing (13) matches the end face long thread of the large throttle valve shaft (7).

6. The two-stage back pressure adjustment mechanism according to claim 4, characterized in that: The large throttle valve (4) is a cone-shaped frustum with a cone angle of 60°. The inner diameter of the large throttle valve (4) matches the outer diameter of the small throttle valve shaft (17) with clearance fit. The large throttle valve (4) has a boss end face as a locking cover, which is pressed and fitted with the locking nut II (12). The other end face of the large throttle valve's internal thread is the sealing surface of the large throttle valve, which is pressed and fitted with the copper washer II (14).

7. The two-stage back pressure adjustment mechanism according to claim 6, characterized in that: The small throttle valve (3) has a front spherical throttle surface and a rear conical throttle surface boss structure.

8. The two-stage back pressure adjustment mechanism according to claim 7, characterized in that: The small throttle valve (3) has a spherical radius of R30 and a conical included angle of 64° at the tail.

9. A two-stage back pressure adjustment mechanism according to any one of claims 1-8, characterized in that: The small throttle valve (3) has a boss inside, which has an internal threaded hole. The threaded hole specification matches the small throttle valve end face thread of the small throttle valve shaft (17). The boss sealing end face is pressed and fitted with the locking nut I (2).

10. A two-stage back pressure adjustment mechanism according to any one of claims 1-8, characterized in that: The throttling tube (1) is made of heat-resistant ferrosilicon cast iron; three measuring point interfaces are arranged in the circumferential direction of the outer periphery of the cylindrical tube, with each measuring point spaced 60° apart, and the threads of the measuring point interfaces are matched with the threads of the temperature and pressure sensors.

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