A diesel engine multi-valve intake port performance test device and test method

Abstract

The present invention discloses a diesel engine multi-valve intake duct performance test device and test method, which mainly includes a flow meter, an intake duct hose, a valve seat, a cylinder head, an intake electric actuator, a valve guide, a sealing plate, an intake spring, a boss, a valve, a transparent cylinder liner, a valve seat valve stem, a multi-rotation electric actuator, a cylinder base plate, a cylinder base plate valve stem, an exhaust electric actuator, a swivel, an airway pressure sensor, an in-cylinder pressure sensor, an airway temperature sensor, and a data acquisition system. The valve lift is controlled by a linearly driven electric actuator to regulate the up and down movement of the intake valve guide and valve. The valve seat is connected to the swivel, and the multi-rotation electric actuator drives the valve seat through the valve seat valve stem, so that the swivel can move in a plane within the hollow area of ​​the cylinder head perpendicular to the valve guide axis. The nested intake duct and snap-on cylinder liner are used to adjust the intake position and cylinder diameter, realizing variable multi-valve airway performance testing.

Description

Technical Field

[0001] The present invention relates to a diesel engine multi-valve intake duct performance test device and test method, in particular to a test device for the multi-valve intake duct performance of medium and small power diesel engines and a method for testing the intake duct performance of medium and small power diesel engines in special environments (high altitude, high temperature, and high humidity environments). Background Art

[0002] As a crucial component of the engine's air intake system, the intake duct's performance and compatibility with the engine directly impact the engine's operating state, and thus the stability and overall performance of the entire powertrain. In high-altitude, cold regions, the unique and harsh environment of the intake duct significantly impacts powertrain performance. Therefore, testing intake duct performance and optimizing its design are crucial.

[0003] Chinese patent CN109781420A discloses a visual engine high-pressure tumble intake test device. This device allows tracer particles generated by a particle generator to enter a transparent simulated cylinder along with the high-pressure gas. The movement of the tracer particles within the simulated cylinder is then observed using visual testing technology, visually demonstrating the changing patterns of tumble flow in a gasoline engine's intake duct under high intake pressure. Valve lift is controlled by a valve lift adjustment mechanism and detected by a valve lift sensor. The intake duct position and the simulated cylinder diameter are constant factors.

[0004] Existing diesel engine intake duct performance evaluation methods are generally based on an air duct steady flow test bench, which mainly evaluates the intake level and vortex organization capability of the air duct itself. It has no direct relationship with the actual combustion and emission performance of the diesel engine, which leads to low accuracy in diesel engine intake duct performance evaluation.

[0005] Chinese patent CN108303229A discloses a device and method for evaluating the performance of a high-speed aircraft inlet with a forced transition device. The device includes a flow transition position determination module, a high-speed aircraft with a forced transition device, a flow field determination module, an inlet performance extraction module, and an inlet performance evaluation module. By analyzing the flow of an aircraft with a forced transition device, the device obtains a characteristic quantity (streamwise vortex length) that characterizes the flow behind the forced transition device, enabling a more accurate simulation of the flow pattern on the aircraft surface. Analyzing inlet performance using fully laminar flow calculation methods cannot simulate the actual flow pattern.

[0006] In general, there is currently a lack of testing equipment to investigate the effects of intake duct position and cylinder diameter on duct performance, as well as a lack of methods to treat the entire in-cylinder flow field as a turbulent flow state to simulate the flow state in the intake duct and thus evaluate intake duct performance. Summary of the Invention

[0007] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a diesel engine multi-valve intake duct performance test device and performance test method, especially a variable multi-valve intake duct performance test device for small and medium-power diesel engines under special environments (high altitude, high temperature, and high humidity environments), and observe the flow field movement in the gas cylinder through a transparent cylinder liner visualization method.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A diesel engine multi-valve intake duct performance test device, comprising: a gas preparation device, a stop valve, a flow meter, a gas pressure regulating box, an intake duct hose, a valve seat, a cylinder head, an intake electric actuator, a valve guide, an intake spring, a valve, a transparent cylinder sleeve, a valve seat valve stem, a multi-rotation electric actuator, a cylinder base plate, a cylinder base plate valve stem, an exhaust electric actuator, a collector, a computer, a buckle, a sealing nylon ring, a swivel, a cylinder head hollow area, an airway pressure sensor, an in-cylinder pressure sensor, an airway throat pipe, an airway Temperature sensor, boss and sealing plate; wherein: the gas output by the gas preparation device passes through the stop valve, flow meter, gas pressure stabilizing box and intake duct hose in sequence and is sent into the air duct from the upper side of the valve seat by the intake duct hose, and a pressure sensor is arranged in the air duct to detect the intake pressure; the valve seat is installed on the cylinder head above the valve, and the valve guide passes through the valve seat from top to bottom and is connected to the valve. A boss is provided in the middle of the valve guide, and a sealing plate connected to the valve seat is provided on the top of the valve guide. An intake spring is disposed between the cylinder head and the intake valve. During intake, the valve lift movement is driven by an intake electric actuator, which controls the up and down movement of the valve guide. Under the action of the intake spring, the valve opening and closing are regulated. At the same time, a position sensor disposed within the intake electric actuator collects the opening and closing times of the valve. The rotator is disposed outside the airway throat and connected to the valve seat. The valve seat valve stem is disposed on the outer wall of the valve seat. The multi-rotation electric actuator controls the rotator via the valve seat valve stem, causing the rotator to move in a plane within a hollow area of ​​the cylinder head perpendicular to the axis of the valve guide, while simultaneously moving the valve guide and the valve in the same direction, thereby achieving adjustable intake duct position. A position sensor disposed within the multi-rotation electric actuator collects the offset distance of the rotator and determines the distance the intake duct position changes. The transparent cylinder liner is connected to the cylinder head via a snap-fit ​​connection. The flowmeter, airway pressure sensor, airway temperature sensor, in-cylinder pressure sensor, collector, and computer constitute a data acquisition system for collecting intake and exhaust pressure, temperature, and flow data. The multi-rotation electric actuator drives the valve seat and the swivel to move in a plane within the hollow area of ​​the cylinder head, thereby achieving adjustable intake duct position; by changing the intake duct position, the distance between the intake duct entrance and the cylinder wall is changed, thereby testing the intake unevenness caused by changing the intake resistance and matching the optimal intake duct position; by removing and installing transparent cylinder liners of different cylinder diameters, the cylinder diameter is adjusted; and the air duct performance is tested by controlling the two factors of air duct position and cylinder diameter.

[0010] Furthermore, when the valve seat and the swivel move in a plane to change the position of the intake passage, the valve guide and the valve are driven to move in the same direction through the sealing plate, and the axes of the valve guide and the valve seat are coaxial.

[0011] Furthermore, the transparent cylinder sleeve is detachable and has a variety of cylinder diameters, and transparent cylinder sleeves with different cylinder diameters are selected before each experiment.

[0012] Furthermore, the gas preparation device is used to perform corresponding cooling, heating and humidification treatment on the air at room temperature to form specific gases that simulate special environments (high altitude, cold, high temperature and high humidity environments), and at the same time transmit relevant data of the gas to the computer.

[0013] Furthermore, it also includes a particle generator, a camera, a laser and a reflector for realizing the measurement of the visualized flow field in the cylinder. The particle generator is located between the flow meter and the gas pressure stabilizing box, the reflector is arranged on the lower side of the transparent cylinder liner, the laser is arranged on the left side of the reflector, and the camera is arranged on the front side of the transparent cylinder liner; the camera and laser are respectively connected to a computer.

[0014] Furthermore, in the intake state, the valve lift movement is driven by the intake electric actuator, which controls the up and down movement of the valve guide. Under the action of the intake spring, the opening of the valve is regulated. After the valve is opened, the gas fully enters the transparent cylinder sleeve, and the in-cylinder pressure sensor monitors the pressure changes in the cylinder in real time; after the gas fully enters the transparent cylinder, the valve is closed, and the visual measurement of the in-cylinder flow field is realized through the camera, laser, and reflector.

[0015] Furthermore, in the exhaust state, the exhaust electric actuator controls the valve stem located on the cylinder base plate to push the cylinder base plate upward, and at the same time the intake electric actuator drives the valve to open, so that the gas in the cylinder is completely discharged from the cylinder. During exhaust, the airway pressure sensor and the airway temperature sensor collect the pressure and temperature changes of the exhaust gas.

[0016] Furthermore, the laser emitted by the laser is reflected by a reflector into the transparent cylinder sleeve to form a sheet light source. The tracer particles generated by the particle generator enter the transparent cylinder sleeve along with the gas. A camera is then used to take pictures perpendicular to the sheet light source to obtain a flow image of the gas in the cylinder and input it into a computer for storage, thereby forming an in-cylinder flow field visualization system.

[0017] A method for testing the performance of a diesel engine intake duct, using the intake duct performance testing device of the present invention, comprises the following steps:

[0018] Step (1), obtaining the temperature, pressure and flow of the intake fluid according to the set multiple sets of "intake duct position-cylinder diameter size" data;

[0019] Step (2), calibrating the intake duct three-dimensional model for numerical simulation using Fluent software;

[0020] Step (3), under the premise of the current intake port position and cylinder diameter size, the intake adopts the full turbulent flow field mode to calculate the intake port performance;

[0021] Step (4) extracts the flow field of the inlet cross section, sets the boundary conditions of the airway inlet, and uses Fluent software to numerically simulate the full turbulent flow field to obtain the inlet performance. The inlet performance includes the inlet cross section flow rate, total pressure recovery coefficient, flow coefficient, and resistance coefficient;

[0022] Step (5) compares the results with the intake duct performance index to effectively evaluate the diesel engine intake duct performance; and compares the effects of different environmental characteristic gases on the intake performance to improve the accuracy of the diesel engine intake duct performance evaluation.

[0023] Beneficial effects of the present invention:

[0024] The present invention primarily utilizes a gas preparation device to prepare gases with varying environmental characteristics. A multi-turn electric actuator drives the valve seat and swivel to move in a plane within the hollow area of ​​the cylinder head, achieving adjustable intake manifold position. Cylinder liners of varying bore diameters can be removed and installed to adjust the cylinder diameter. Controlling both the air manifold position and cylinder diameter, the air manifold performance and in-cylinder flow field are tested on an experimental platform with adjustable air manifold position and cylinder diameter. Numerical simulation is used to calculate the full turbulence model, determining the full turbulent flow field within the intake manifold and cylinder. Physical quantities at the intake manifold inlet and throat sections are extracted to obtain intake manifold performance parameters. Multiple valves work in concert to expand the total intake manifold cross-sectional area, increasing the intake manifold cross-sectional flow rate, boosting intake and exhaust volume, improving intake and exhaust efficiency, and achieving more complete engine combustion. Changing the intake manifold position alters the distance between the intake manifold inlet and cylinder wall, affecting intake resistance and altering intake unevenness. Through multiple experiments, the optimal intake manifold position can be determined based on intake performance requirements. The relevant data obtained from the experiment are calibrated in the model, and the simulation is combined with the experiment to verify the airway performance and the flow field characteristics in the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an axonometric view of the air intake performance testing device of the present invention.

[0026] Figure 2 The right side view of the intake duct performance test device of the present invention is a sectional view along the valve guide axis (with Figure 1 (same scale cutaway view).

[0027] Figure 3 It is a partially enlarged view of the cross-sectional view of the right side view of the intake duct performance testing device of the present invention along the valve guide axis.

[0028] Figure 4 It is a schematic diagram of the air intake performance testing device of the present invention.

[0029] Figure 5 Flowchart of the intake duct performance evaluation method of the present invention.

[0030] The reference numerals in the figures are:

[0031] Gas preparation device 1, stop valve 2, flow meter 3, particle generator 4, intake pressure stabilizing box 5, intake duct hose 6, valve seat 7, cylinder head 8, intake electric actuator 9, valve guide 10, intake spring 11, valve 12, transparent cylinder sleeve 13, valve seat valve stem 14, multi-turn electric actuator 15, cylinder base plate 16, cylinder base plate valve stem 17, exhaust electric actuator 18, camera 19, laser 20, reflector 21, collector 22, computer 23, buckle 24, sealing nylon ring 25, swivel 26, cylinder head hollow area 27, airway pressure sensor 28, in-cylinder pressure sensor 29, airway throat 30, airway temperature sensor 31, boss 32, sealing plate 33. DETAILED DESCRIPTION

[0032] The experimental device of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] like Figure 1-4 As shown, a diesel engine multi-valve intake duct performance test device includes: a gas preparation device 1, a stop valve 2, a flow meter 3, a particle generator 4, a gas pressure stabilizing box 5, an intake duct hose 6, a valve seat 7, a cylinder head 8, an intake electric actuator 9, a valve guide 10, an intake spring 11, a valve 12, a transparent cylinder sleeve 13, a valve seat valve stem 14, a multi-rotation electric actuator 15, a cylinder base plate 16, a cylinder base plate valve stem 17, an exhaust electric actuator 18, a camera 19, a laser 20, a reflector 21, a collector 22, a computer 23, a buckle 24, a sealing nylon ring 25, a swivel 26, a cylinder head hollow area 27, an airway pressure sensor 28, an in-cylinder pressure sensor 29, an airway throat 30, an airway temperature sensor 31, a boss 22 and a sealing plate 33.

[0034] in:

[0035] The gas preparation device 1 is used to perform corresponding cooling, heating, and humidification on the normal temperature air to form a specific gas, and transmit the relevant data of the gas to the computer 23;

[0036] The gas output from the gas preparation device 1 passes through the stop valve 2, flow meter 3, particle generator 4, gas pressure regulating box 5 and intake hose 6 in sequence and is delivered into the airway through the upper side of the valve seat 7 by the intake hose 6. A pressure sensor 28 is arranged in the airway to detect the intake pressure.

[0037] The valve seat 7 is installed on the cylinder head 8 above the valve 12. The valve guide 10 passes through the valve seat 7 from top to bottom and is connected to the valve 12. A boss 32 is provided in the middle of the valve guide 10. A sealing plate 33 connected to the valve seat 7 is provided on the top of the valve guide 10. An intake spring 11 is provided between the boss 32 and the sealing plate 33. During intake, the valve lift movement is driven by the intake electric actuator 9 (straight-step electric actuator) to control the up and down movement of the valve guide 10. Under the action of the intake spring 11, the opening and closing of the valve 12 are regulated. At the same time, the position sensor arranged inside the intake electric actuator 9 can record the opening and closing time of the valve 12.

[0038] The swivel 26 is arranged on the outside of the airway throat 30 and is connected to the valve seat 7, and the valve seat stem 14 is arranged on the outer wall of the valve seat 7; the multi-rotation electric actuator 15 controls the swivel 26 through the valve seat stem 14, so that the swivel 26 moves in a plane within the hollow area 27 of the cylinder head perpendicular to the axis of the valve guide 10, while carrying the valve guide 10 and the valve 12 to move in the same direction, thereby realizing the adjustable position of the intake duct; the position sensor arranged inside the multi-rotation electric actuator 15 can collect the offset distance of the swivel 26, thereby knowing the distance of the change in the intake duct position.

[0039] When the valve seat 7 and the swivel 26 move in a plane to change the position of the intake passage, the valve guide 10 and the valve 12 are driven to move in the same direction through the sealing plate 33 . The axis of the valve guide 10 and the valve seat 7 are coaxial.

[0040] The transparent cylinder liner 13 is detachable and is connected to the cylinder head 8 by a buckle. Before each experiment, the cylinder diameter is changed by replacing the transparent cylinder liner 13 with a different cylinder diameter. The position of the transparent cylinder liner 13 is fixed by the buckle 24, and the sealing nylon ring 25 seals the cylinder liner 13 to the cylinder head 8.

[0041] In the intake state, the gas preparation device 1 transmits the gas to the intake duct hose 6 in sequence. The pressure and temperature of the gas during intake are collected by the collector 22 through the air duct pressure sensor 28 and the air duct temperature sensor 31; the valve lift movement is driven by the intake electric actuator 9 (straight-step electric actuator), which controls the up and down movement of the valve guide 10. Under the action of the intake spring 11, the opening of the valve 12 is regulated. After the valve 12 is opened, the gas fully enters the transparent cylinder sleeve 13, and the cylinder pressure sensor 29 monitors the pressure changes in the cylinder in real time; after the gas fully enters the transparent cylinder, the valve 12 is closed, and the visual measurement of the cylinder flow field is realized through the camera 19, laser 20, and reflector 21.

[0042] In the exhaust state, the exhaust electric actuator 18 (straight-step electric actuator) controls the valve stem 17 located on the cylinder base plate to push the cylinder base plate 16 upward, and at the same time the intake electric actuator 9 (straight-step electric actuator) drives the valve 12 to open, so that the gas in the cylinder is completely discharged from the cylinder. During exhaust, the airway pressure sensor 28 and the airway temperature sensor 31 collect the pressure and temperature changes of the exhaust gas; finally, the gas is recovered into the gas preparation device 1 for recycling.

[0043] The flow meter 3, the airway pressure sensor 28, the airway temperature sensor 31, the in-cylinder pressure sensor 29, the collector 21 and the computer 23 constitute a data acquisition system to collect changes in the pressure, temperature and flow of the intake and exhaust gases.

[0044] The transparent cylinder sleeve 13, camera 19, laser 20, and reflector 21 realize the measurement of the visualized flow field in the cylinder. The reflector 21 is arranged on the lower side of the transparent cylinder sleeve 13, the laser 20 is arranged on the left side of the reflector 21, and the camera 19 is arranged on the front side of the transparent simulation cylinder 13 sleeve.

[0045] Camera 19 and laser 20 are connected to computer 23. Laser 20 emits laser light, which is reflected by reflector 21 and enters transparent cylinder liner 13 to form a light sheet. Tracer particles generated by particle generator 4 enter transparent cylinder liner 13 along with the gas. Camera 19 then takes a picture perpendicular to the light sheet, obtaining an image of the gas flow in the cylinder and storing it in the computer.

[0046] The particle generator 4, the transparent cylinder sleeve 13, the camera 19, the laser 20, the reflector 21, the collector 22, and the computer 23 constitute an in-cylinder flow field visualization system.

[0047] like Figure 5 As shown, the method for implementing the intake duct performance test using the intake duct performance test device of the present invention includes:

[0048] Step (1), obtaining the temperature, pressure and flow of the intake fluid according to the set multiple sets of "intake duct position-cylinder diameter size" data;

[0049] Step (2), calibrating the intake duct three-dimensional model for numerical simulation using Fluent software;

[0050] Step (3), under the premise of the current intake port position and cylinder diameter size, the intake adopts the full turbulent flow field mode to calculate the intake port performance;

[0051] Step (4) extracts the flow field of the inlet cross section, sets the boundary conditions of the airway inlet, and uses Fluent software to numerically simulate the full turbulent flow field to obtain the inlet performance. The inlet performance includes the inlet cross section flow rate, total pressure recovery coefficient, flow coefficient, and resistance coefficient;

[0052] Step (5) is to compare with the intake duct performance index, effectively evaluate the diesel engine intake duct performance, compare the effects of different environmental characteristic gases on the intake performance, and improve the accuracy of the diesel engine intake duct performance evaluation.

[0053] The words used to express position and direction in this application are all illustrated by the accompanying drawings, but can be modified as needed, and all such modifications are included within the scope of protection of this application. The accompanying drawings in this application are only used to illustrate relative position relationships and do not represent true proportions.

Claims

1. A diesel engine multi-valve intake port performance test device, characterized in that: The device comprises a flow meter (3), an intake hose (6), a valve seat (7), a cylinder head (8), an intake electric actuator (9), a valve guide (10), an intake spring (11), a valve (12), a transparent cylinder sleeve (13), a valve seat valve stem (14), a multi-rotation electric actuator (15), a cylinder base plate (16), a cylinder base plate valve stem (17), an exhaust electric actuator (18), a collector (22), a computer (23), a buckle (24), a sealing nylon ring (25), a swivel (26), a cylinder head hollow area (27), an airway pressure sensor (28), an in-cylinder pressure sensor (29), an airway throat (30), an airway temperature sensor (31), a boss (32) and a sealing plate (33); wherein: The intake hose (6) is connected to the upper side of the valve seat (7) and delivers the intake air into the airway. The flow meter (3) is connected in series in front of the intake hose (6). A pressure sensor (28) is arranged in the airway to detect the intake pressure. The valve seat (7) is mounted on the cylinder head (8) above the valve (12), and the valve guide (10) passes through the valve seat (7) from top to bottom and is connected to the valve (12). A boss (32) is provided in the middle of the valve guide (10), and a sealing plate (33) connected to and matched with the valve seat (7) is provided on the top of the valve guide (10). An intake spring (11) is provided between the boss (32) and the sealing plate (33). During intake, the valve lift movement is driven by the intake electric actuator (9) to control the up and down movement of the valve guide (10). Under the action of the intake spring (11), the opening and closing of the valve (12) are regulated, and at the same time, a position sensor provided inside the intake electric actuator (9) collects the opening and closing time of the valve (12); The swivel (26) is arranged outside the airway throat (30) and connected to the valve seat (7), and the valve seat valve stem (14) is arranged on the outer wall of the valve seat (7). The multi-rotation electric actuator (15) controls the swivel (26) through the valve seat valve stem (14), so that the swivel (26) moves in a plane in the cylinder head hollow area (27) perpendicular to the axis of the valve guide (10), and at the same time carries the valve guide (10) and the valve (12) to move in the same direction, thereby realizing the adjustable position of the intake duct. At the same time, the position sensor arranged inside the multi-rotation electric actuator (15) collects the offset distance of the swivel (26) and obtains the distance of the change in the position of the intake duct; The transparent cylinder sleeve (13) is connected to the cylinder cover (8) via a buckle (24); The flow meter (3), the airway pressure sensor (28), the airway temperature sensor (31), the in-cylinder pressure sensor (29), the collector (22) and the computer (23) constitute a data acquisition system for collecting data on the pressure, temperature and flow of the intake and exhaust gases; The multi-rotation electric actuator (15) drives the valve seat (7) and the swivel (26) to move in a plane within the hollow area (27) of the cylinder head, thereby achieving adjustable intake duct position; by changing the intake duct position, the distance between the intake duct entrance and the cylinder wall is changed, thereby testing the intake unevenness caused by changing the intake resistance and matching the optimal intake duct position; by disassembling and installing transparent cylinder sleeves (13) of different cylinder diameters, the cylinder diameter is adjusted; and the air duct performance is tested by controlling the two factors of air duct position and cylinder diameter.

2. A diesel engine multi-valve intake port performance test device according to claim 1, characterized in that: In the process of the valve seat (7) and the rotating body (26) moving in a plane to change the position of the air inlet, the valve guide (10) and the valve (12) are driven to move in the same direction through the sealing plate (33), and the axis of the valve guide (10) and the valve seat (7) are coaxial.

3. A diesel engine multi-valve intake port performance test device according to claim 1, characterized in that: The transparent cylinder sleeve (13) is detachable and has a variety of cylinder diameters. Transparent cylinder sleeves (13) with different cylinder diameters are selected before each experiment.

4. A diesel engine multi-valve intake port performance test device according to claim 1, characterized in that: The invention also includes a gas preparation device (1), a stop valve (2), a flow meter (3) and a gas pressure stabilizing box (5) which are connected in sequence and are located in front of the air inlet hose (6), and the flow meter (3) is located between the stop valve (2) and the gas pressure stabilizing box (5); the gas preparation device (1) is used to perform corresponding cooling or heating and humidification treatment on the normal temperature air to form a specific gas simulating the high altitude cold, high temperature and high humidity environment, and at the same time transmit the relevant data of the gas to the computer (23).

5. The diesel engine multi-valve intake port performance test device according to claim 1, characterized in that: The apparatus further comprises a particle generator (4), a camera (19), a laser (20) and a reflector (21) for realizing the measurement of the visualized in-cylinder flow field. The particle generator (4) is located between the flow meter (3) and the gas pressure regulating box (5). The reflector (21) is arranged on the lower side of the transparent cylinder sleeve (13). The laser (20) is arranged on the left side of the reflector (21). The camera (19) and the laser (20) are respectively connected to a computer (23).

6. A diesel engine multi-valve intake port performance test device according to claim 5, characterized in that: In the intake state, the valve lift movement is driven by the intake electric actuator (9), which controls the up and down movement of the valve guide (10). Under the action of the intake spring (11), the opening of the valve (12) is regulated. After the valve (12) is opened, the gas fully enters the transparent cylinder sleeve (13), and the cylinder pressure sensor (29) monitors the pressure change in the cylinder in real time; after the gas fully enters the transparent cylinder, the valve (12) is closed, and the visual measurement of the cylinder flow field is achieved through the camera (19), laser (20), and reflector (21).

7. A diesel engine multi-valve intake port performance test device according to claim 5, characterized in that: In the exhaust state, the exhaust electric actuator (18) controls the valve stem (17) located on the cylinder base plate to push the cylinder base plate (16) upward, and at the same time the intake electric actuator (9) drives the valve (12) to open, so that the gas in the cylinder is completely discharged from the cylinder. During exhaust, the airway pressure sensor (28) and the airway temperature sensor (31) collect the pressure and temperature changes of the exhaust gas.

8. The diesel engine multi-valve intake port performance test device according to claim 5, characterized in that: The laser (20) emits laser light, which is reflected by the reflector (21) and enters the transparent cylinder sleeve (13) to form a light sheet. The tracer particles generated by the particle generator (4) enter the transparent cylinder sleeve (13) along with the gas. Then, a camera (19) is used to take a picture perpendicular to the light sheet to obtain a flow image of the gas in the cylinder and input it into a computer (23) for storage, thereby forming a flow field visualization system in the cylinder.

9. A diesel engine intake duct performance testing method, characterized in that: Utilizing a diesel engine multi-valve intake port performance testing device according to any one of claims 1 to 7, the method comprises the following steps: Step (1), obtaining the temperature, pressure and flow of the intake fluid according to the set multiple sets of "intake port position-cylinder diameter size" data; Step (2), calibrating the intake duct three-dimensional model for numerical simulation using Fluent software; Step (3), calculating the intake duct performance using the full turbulent flow field under the premise of the current intake duct position and cylinder diameter size; Step (4) extracts the cross-sectional flow field of the entire turbulent flow field, sets the boundary conditions of the inlet, and uses Fluent software to numerically simulate the entire turbulent flow field to obtain the inlet performance; the inlet performance includes the inlet cross-sectional flow rate, total pressure recovery coefficient, flow coefficient, and drag coefficient; Step (5) is compared with the intake duct performance index to effectively evaluate the diesel engine intake duct performance.

10. The testing method according to claim 9, wherein: Comparison of the effects of different environmental characteristic gases on intake performance is used to improve the accuracy of diesel engine intake port performance evaluation.

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