Plateau alpine environment diesel engine fuel spray simulation test device and test method

Abstract

This invention discloses a diesel engine fuel spray simulation test device and method for high-altitude and cold-weather environments. The device includes fuel storage and pretreatment equipment, a fuel injection system, an optical visualization system, an environmental chamber, and a spray pretreatment system. This device can achieve high-pressure liquid injection in high-altitude and cold-weather environments. It separates the sprayed mist into fine droplets through a multi-droplet generation device and a wall device, and impacts the wall surface. The entire process is observed and recorded through an optical visualization channel. This invention avoids the problem of sprays forming large patches that are difficult to distinguish from droplets, significantly reduces the cost of traditional spray and droplet testing schemes, and solves the problem of high dependence on control programs in constant-volume projectile schemes. This invention can simulate spray tests in high-altitude and cold-weather environments. The test device has a simple structure and can realize the study of free spraying, multi-droplet wall impact, spray wall impact, and the laws governing their development characteristics under different altitudes and temperatures.

Description

Technical Field

[0001] This invention relates to a fuel spray simulation test device, and more particularly to a fuel spray simulation test device and test method for diesel engines in high-altitude and cold environments. Background Technology

[0002] In applications of internal combustion engines in high-altitude regions, high-altitude drone operations during rain, snow, and hail, and agricultural and forestry pesticide spraying, the free development and impact processes of liquid mist or droplets are involved. Therefore, researchers need to conduct extensive experimental studies in this area. However, due to the complexity of the high-altitude environment and limitations in testing methods, most researchers currently focus on studying the changing characteristics of the entire spray or individual droplets. The entire spray is usually a dark area, making it difficult to obtain more precise characteristics beyond analyzing the edge contours.

[0003] Research reports on engine fuel injection and combustion primarily employ constant-volume injection to simulate the temperature and pressure environment within the engine cylinder. This system is complex, requiring the implementation of functions such as fuel injection control, ambient pressure and temperature control, laser (illuminating the spray) control, and high-speed camera capture of images while the laser is emitting light. Furthermore, these functions must be coordinated, resulting in a strong dependence on the control system and consequently high costs and technical difficulty. While injectors themselves have multiple nozzles for multi-point injection, the high injection pressure and continuous spraying process result in a dense, cone-shaped mist. The lack of a simple, efficient, and easily operable system is a widely acknowledged problem in the industry.

[0004] CN112945536A discloses a spray droplet separation device, a spray visualization testing system, and its usage method. The spray droplet separation device includes a height adjustment frame, a support plate horizontally mounted on the height adjustment frame, and two baffles symmetrically arranged on the support plate; a separation gap is formed between the baffles. During experimental testing, the nozzle sprays spray vertically downwards. Most droplets in the dense spray area collide with the baffles. The two baffles intercept most of the droplets in the dense spray area, while a very small portion of droplets passes through the separation gap and continues to move, achieving the purpose of reducing the number and concentration of droplets in the dense spray area. This allows for the capture of clear droplet images of the separated dense spray area using optical photography, enabling those skilled in the art to detect the microscopic behavior characteristics of droplets in the dense central area of ​​the spray. However, while the disclosed droplet generation device can reduce the number and concentration of droplets in the dense spray area, it essentially cuts the spray into a flat surface. The central area of ​​the obtained spray image is usually a continuous sheet, making it difficult to obtain clear droplet images.

[0005] In high-altitude and frigid environments, low temperatures increase liquid viscosity, especially during internal combustion engine operation, where fuel injection atomization becomes worse and the spray becomes denser, making conventional testing methods less effective. Therefore, developing a spray simulation testing device and obtaining separated multi-droplet images for analysis would accelerate advancements in this field.

[0006] Overall, the main shortcomings of existing technologies are:

[0007] (1) Using two opposing blades as the structure for cutting the spray to generate droplets, the effect of this scheme is to divide the spray, and after the division, a piece of spray is generated. The central area is still easy to connect into a piece, making it difficult to distinguish droplets.

[0008] (2) Existing technologies mainly rely on constant-volume incendiary bombs, lasers, and high-speed cameras for visualization studies of sprays or droplets impacting walls. Constant-volume bombs are expensive and highly dependent on control programs. Summary of the Invention

[0009] The technical problem this invention aims to solve is to overcome the aforementioned shortcomings and provide a diesel engine fuel spray simulation test device and method for high-altitude and cold-weather environments. The main purpose is to study the free / impact-wall development process of spray / multi-droplet systems under high-altitude and cold-weather environmental conditions. The device and test method of this invention are simple to operate, can generate continuous multi-droplet systems, and avoid the problem of sprays forming patches that are difficult to distinguish from droplets. This significantly reduces the cost of traditional spray and droplet test schemes and solves the problem of high dependence on control programs in constant-volume projectile schemes.

[0010] The technical solution adopted in this invention is:

[0011] A diesel engine fuel spray simulation test device for high-altitude and cold-weather environments is disclosed. This device enables high-pressure liquid injection in high-altitude and cold-weather conditions. It separates the sprayed mist into fine droplets using a multi-droplet generation device and a wall-mounted device, and the droplets impact the wall surface. The entire process is observed and recorded through an optical visualization channel. The device includes a fuel storage and pretreatment unit 1, a fuel injection system, an optical visualization system, an environmental chamber 10, and a spray pretreatment system.

[0012] The functions of the fuel storage and pretreatment equipment 1 include fuel storage, fuel heating, fuel pressurization, and fuel temperature and pressure pretreatment control program.

[0013] The fuel injection system includes a bracket 2, a high-pressure fuel line 3, a return fuel line 4, an injector 5, and a pulse controller 6.

[0014] The fuel storage and pretreatment device 1 is connected to the fuel inlet and outlet ports of the injector 5 via a high-pressure fuel line 3. The pulse controller 6 is connected to the injector 5 via a solenoid valve. The position of the injector 5 is determined by a bracket 2, which consists of a crossbar and a longitudinal bar. A clamp is located at the end of the crossbar for clamping and fixing the injector. The clamp is connected to the crossbar via a bearing, and the angle is adjustable. The longitudinal bars of the bracket are threaded, and the crossbar and longitudinal bar are connected by threads. The height of the crossbar is adjustable by the threads.

[0015] The optical visualization system includes a computer 7, a high-speed camera 8, a light source 9, and an environmental cavity 10. The environmental cavity 10 is cylindrical and made of transparent quartz glass. A nozzle 5 is installed by drilling holes at the top, and an interface is reserved on the side for connecting an environmental control device.

[0016] The spray pretreatment system includes a multi-droplet generator 11, a wall-impact device 12, and a support screw 13, all housed within a transparent environmental cavity 10. The multi-droplet generator 11 is made of metal sheet processed into a semi-circular arc structure with several holes on its arc surface, which can directly divide the continuous spray generated by the injector 5 into droplets. The side of the semi-circular arc structure facing the injector 5 is concave, and an absorbent material 14 is adhered to this concave side to absorb and recover excess liquid that has been intercepted and has not passed through the holes. The wall-impact device 12 is located below the arc of the multi-droplet generator 11 and is mounted on the support screw 13 to simulate the wall-impact process of the spray 15 or droplets 16.

[0017] A rectangular plate is welded to each of the two edges of the semi-circular metal plate. Each plate has a threaded hole, which is fastened to the support screw 13.

[0018] The impact device 12 is fixed on the support screw 13. Since the injector is at a certain angle to the cylinder side wall in the diesel engine cylinder, the shape of the impact device 12 can be a planar surface perpendicular to the injector; it can also be an inclined surface at a 45° angle to the injector; or it can be an arc surface closer to the cylinder side wall, with the arc radius consistent with the cylinder radius simulated in the test.

[0019] The working principle of the diesel engine fuel spray simulation test device for high-altitude and cold environments is as follows:

[0020] The fuel storage and pretreatment equipment 1 has a built-in fuel storage tank and a device for adjusting the fuel according to preset parameters.

[0021] The bracket 2 consists of a right-angled horizontal bar and a vertical bar, which are connected by threads. The height of the horizontal bar is adjusted by the threads. There is a clamp at the end of the horizontal bar for clamping and fixing the injector 5. The clamp is connected to the horizontal bar by a bearing, and the angle of the clamp is adjustable.

[0022] The position, number, shape, and angle of adjacent holes on the arc surface of the multi-droplet generator 11 can be changed according to experimental requirements. To ensure the accuracy of the experimental results, while preventing droplet breakage and minimizing droplet aggregation into liquid columns, the diameter of the holes should be controlled between 0.2 mm and 1 mm, and the distance between adjacent holes should be at least one hole diameter. The sector angle of the arc surface should be at least greater than 15°, and the shape of the arc should be similar to the shape of the injector nozzle. The arrangement of the number of holes is calculated based on the distance between the center point of the bottom of the arc surface and the injector nozzle, which will be further explained later with reference to embodiments and schematic diagrams.

[0023] The environmental cavity 10 is cylindrical and made of two layers of transparent quartz glass. Except for the passage range required for the operation of the high-speed camera 8 and the light source 9, it is wrapped with heat insulation material to maintain temperature stability. The reserved hole positions need to be sealed with sealing material after the complete set of equipment is installed. An oil mist absorption device 17 is installed on the right side of the top surface of the environmental cavity 10. It is turned on after each test shooting to remove oil mist in the environmental cavity 10.

[0024] The aforementioned diesel engine fuel spray simulation test device for high-altitude and cold-weather environments comprises an environmental chamber 10 for independent environmental regulation, a fuel storage and pretreatment device 1 for fuel injection control, and a visualization pathway for acquiring spray images. Each module operates independently. Compared to traditional constant-volume injection systems, it features a simpler structure, lower cost, and the use of the fuel storage and pretreatment device 1 for fuel injection eliminates the need to integrate fuel injection control with environmental control, reducing the complexity of the control program. Furthermore, it replaces expensive lasers with ordinary LED light sources, lowering costs and reducing the need for synchronous laser control.

[0025] The test method for a diesel engine fuel spray simulation test device in a high-altitude and cold environment is characterized by comprising the following steps:

[0026] S1 Turn on the high-speed camera 8 and light source 9, adjust the position and parameters, use the marked ruler to calibrate the dimensions, and prepare for shooting;

[0027] S2 opens the fuel storage and pretreatment device 1 and sets parameters such as injection pressure, injection quantity, and injection duration;

[0028] S3 adjusts the pulse width and frequency parameters of pulse controller 6;

[0029] After the S4 system reaches the preset injection parameters, click the shooting command on the high-speed camera 8 and click the pulse controller 6 to control the fuel injection.

[0030] S5 shooting finished, turn on the oil mist removal device 17 to remove fog;

[0031] S6 Repeat steps 1-5, and perform each experiment three times;

[0032] S7 acquires image data and performs post-processing.

[0033] The beneficial effects of this invention include:

[0034] This invention enables high-pressure liquid jetting in high-altitude and frigid environments. It separates the sprayed mist into fine droplets using a multi-droplet generation device and a wall-impact device, and the entire process is observed and recorded via an optical visualization channel. This invention generates multiple droplets and avoids the problem of sprays forming large patches that are difficult to distinguish from individual droplets. It significantly reduces the cost of traditional spray and droplet testing methods and solves the problem of high dependence on control programs in constant-volume projectile methods. This invention can simulate spray tests in high-altitude and frigid environments. The testing device has a simple structure and can realize free spraying, multi-droplet wall impact, spray wall impact, and the study of their development characteristics under different altitudes and temperatures. This device provides a foundation for in-depth research on the spray and droplet change mechanisms of powered machinery under special environments. Attached Figure Description

[0035] The invention will be further described below with reference to the accompanying drawings.

[0036] Figure 1 This is a schematic diagram of the overall structure of the high-altitude and cold-weather spray simulation test device of the present invention.

[0037] Figure 2 This is a top view of the multi-droplet separation device of the present invention.

[0038] Figure 3 This is a front view of the multi-droplet separation device of the present invention.

[0039] Figure 4 This is a schematic diagram of an embodiment of the orifice design scheme for the multi-droplet generator of the present invention.

[0040] The attached figures are labeled as follows:

[0041] 1-Fuel storage and pretreatment equipment, 2-Support, 3-High-pressure oil pipe, 4-Return oil pipe, 5-Injector, 6-Pulse controller, 7-Computer, 8-High-speed camera, 9-Light source, 10-Environmental chamber, 11-Multi-droplet generator, 12-Wall impact device, 13-Support screw, 14-Absorbent material, 15-Spray, 16-Droplet, 17-Fuel mist suction device. Detailed Implementation

[0042] Example 1

[0043] A diesel engine fuel spray simulation test device for high-altitude and cold-weather environments is disclosed. This device enables high-pressure liquid injection in high-altitude and cold-weather conditions. It separates the sprayed mist into fine droplets using a multi-droplet generation device and a wall-mounted device, and the droplets impact the wall surface. The entire process is observed and recorded through an optical visualization channel. The device includes a fuel storage and pretreatment unit 1, a fuel injection system, an optical visualization system, an environmental chamber 10, and a spray pretreatment system.

[0044] The functions of the fuel storage and pretreatment equipment 1 include fuel storage, fuel heating, fuel pressurization, and fuel temperature and pressure pretreatment control program. The upper left corner is the wiring area; a glass window is reserved in the lower left corner to observe the current fuel level. When the fuel level is not within the appropriate upper and lower limit range, the fuel level should be adjusted; there is a button switch in the lower right corner for turning the fuel storage and pretreatment equipment 1 on and off.

[0045] The fuel injection system includes a bracket 2, a high-pressure fuel line 3, a return fuel line 4, an injector 5, and a pulse controller 6.

[0046] The fuel storage and pretreatment device 1 is connected to the fuel inlet and outlet ports of the injector 5 via a high-pressure fuel line 3. The pulse controller 6 is connected to the injector 5 via a solenoid valve. The position of the injector 5 is determined by a bracket 2, which consists of a crossbar and a longitudinal bar. A clamp is located at the end of the crossbar for clamping and fixing the injector 5. The clamp is connected to the crossbar via a bearing, and the angle is adjustable. The longitudinal bars of the bracket are threaded, and the crossbar and longitudinal bar are connected by threads. The height of the crossbar is adjustable by the threads.

[0047] The optical visualization system includes a computer 7, a high-speed camera 8, a light source 9, and a transparent environmental cavity 10; the environmental cavity 10 is cylindrical, with a hole drilled in the top to install an oil injector 5, and an interface reserved on the side to install an environmental control device.

[0048] The spray pretreatment system includes a multi-droplet generator 11, a wall-impact device 12, and a support screw 13. The multi-droplet generator 11 has a semi-circular arc-shaped structure with several holes on its arc surface. The position, number, shape, and angle of adjacent holes can be changed according to experimental requirements. The side of the arc facing the injector 5 is concave, and an absorbent material 14 is adhered to this concave side to absorb and recover excess liquid that has been intercepted and failed to pass through the holes. A rectangular plate is welded to each edge of the semi-circular metal plate, and each plate has a threaded hole connected to the support screw 13. A washer and nut are tightened at each connection point to ensure stability during the experiment. The wall-impact device 12, installed on the support screw 13 in the same manner under the arc-shaped structure, can simulate the wall-impact process of the spray 15 or droplets 16.

[0049] The main body of the environmental chamber 10 is made of two layers of transparent quartz glass. Except for the passage area required for the operation of the high-speed camera 8 and the light source 9, the entire area can be wrapped with thermal insulation material to maintain temperature stability as needed for the experiment. The reserved holes must be sealed with sealing material after the entire set of equipment is installed. An oil mist absorption device 17 is installed on the right side of the top surface of the environmental chamber 10. It is turned on after each test shooting to remove oil mist from the environmental chamber 10.

[0050] Example 2

[0051] The present invention also provides a test method using the spray simulation test apparatus of the present invention, the test method comprising:

[0052] Step 1: Check the connection of the high-pressure oil circuit, return oil line, and solenoid valve to ensure the circuit is intact before proceeding to the next step;

[0053] Step 2: Check if the fuel level in the fuel storage and pretreatment equipment 1 is within the upper and lower limits. If it is, proceed to the next step; otherwise, replenish the fuel.

[0054] Step 3: Check if the seal of the environmental cavity 10 is intact. If it is intact, proceed to the next step.

[0055] Step 4: Turn on the switch of fuel storage and pretreatment device 1 and set the fuel injection parameters;

[0056] Step 5: Open the high-speed camera 8 and set the shooting parameters;

[0057] Step 6: Turn on the light source 9, and adjust the positions of the high-speed camera 8, the light source 9, and the fuel injector 5 to ensure that the spray 15 or droplets 16 and their development process can be accurately captured;

[0058] Step 7: Attach two strips of tape to the ruler at 10mm intervals, take photos with a high-speed camera (8) and save them for dimensional calibration purposes;

[0059] Step 8: Start the fuel injection command. When the temperature and pressure reach the set value, click the high-speed camera 8 shooting button, and then adjust the pulse controller 6 to inject fuel three times.

[0060] Step 9: Acquire the image and save the data that meets the requirements;

[0061] Step 10: Turn on the oil mist suction device 17 to remove the oil mist in the ambient chamber 10, and then turn it off;

[0062] Step 11: Repeat steps 3 to 10 (step 7 can be skipped in subsequent experiments depending on the experimental adjustments) until all the results required for the experiment are obtained, and then end the experiment.

[0063] Example 3

[0064] The position, number, and angle of adjacent holes on the arc surface described in this invention can be set according to experimental requirements. An embodiment is provided below as a reference for hole design. Figure 4 As shown, a single-row hole arrangement scheme is adopted, with all holes distributed on the largest arc directly opposite the light source 9 and the high-speed camera 8. Assuming the initial spray cone angle is θ and the distance between the nozzle and the multi-droplet generating device is L, the side length corresponding to angle θ / 2 can be calculated using the triangle tangent function, which is taken as the arc length where the holes can be arranged. The number of holes is set as parameter x, and x (rounded to an integer) can be calculated using the following formulas (1)(2)(3):

[0065]

[0066] W≥x·d+(x-2)·d (2)

[0067]

[0068] The above embodiments are merely examples of one implementation of the present invention, and the scope of the present invention is not limited to the above embodiments. Those skilled in the art can derive more embodiments based on the basic concept of the present invention.

Claims

1. A diesel engine fuel spray simulation test device for high-altitude and cold environments, characterized in that, It includes a fuel storage and pretreatment device (1), a fuel injection system, an optical visualization system, an environmental chamber (10), and a spray pretreatment system; The fuel storage and pretreatment equipment (1) is used to achieve fuel temperature and pressure pretreatment control; The fuel injection system includes a bracket (2), a high-pressure fuel line (3), a return fuel line (4), an injector (5), and a pulse controller (6); the injector (5) is mounted on the bracket (2) and connected to the pulse controller (6); the high-pressure fuel line (3), the injector (5), and the return fuel line (4) form a fuel circuit. The fuel storage and pretreatment equipment (1) is connected to the fuel inlet and return port on the injector (5) through the high-pressure oil pipe (3) and the return oil pipe (4). The pulse controller (6) is connected to the injector (5) through the solenoid valve and controls the injector (5) to achieve fuel injection. The optical visualization system includes a computer (7), a high-speed camera (8), a light source (9), and a transparent environmental cavity (10); the top of the environmental cavity (10) is perforated to install an oil injector (5), and the side is reserved with an interface for connecting an environmental simulation control device; the high-speed camera (8) and the light source (9) are located on opposite sides of the environmental cavity (10); The spray pretreatment system includes a multi-droplet generator (11), a wall-collision device (12), and a support screw (13) placed inside a transparent environmental cavity (10). The multi-droplet generator (11) is made of metal sheet and processed into a semi-circular arc structure with several holes on the arc surface. The side of the semi-circular arc structure facing the injector (5) is a concave side, and an adsorbent material (14) is attached to the concave side to adsorb and recover excess liquid that has been intercepted but has not passed through the holes. The wall-collision device (12) is set below the arc of the multi-droplet generator (11). The wall-collision device (12) is installed on the support screw (13) to simulate the wall-collision process of the spray (15) or droplets (16).

2. The diesel engine fuel spray simulation test device for high-altitude and cold environments according to claim 1, characterized in that: The position, number, shape, and angle of the holes on the arc surface of the multi-droplet generating device (11) can be changed according to the test requirements, including: the diameter of the holes should be controlled between 0.2mm and 1mm, and the distance between adjacent holes should be at least one hole diameter; the fan angle of the arc surface should be greater than 15°, and the shape of the arc should be similar to the shape of the injector nozzle; the number of holes is calculated based on the distance between the center point of the bottom of the arc surface and the injector nozzle.

3. The diesel engine fuel spray simulation test device for high-altitude and cold environments according to claim 2, characterized in that: The location, number, and angle of adjacent holes can be set according to experimental requirements, including: the holes are arranged in a single row, with all holes distributed on the largest arc directly opposite the light source (9) and the high-speed camera (8). Assuming the initial spray cone angle is θ and the distance between the nozzle and the multi-droplet generating device is L, the side length corresponding to angle θ / 2 can be calculated using the tangent function of a triangle as W. W is used as the arc length where holes can be arranged. The number of holes is set as parameter x, which is then calculated by the following formulas (1), (2), and (3) and rounded to the nearest integer: 。 4. A diesel engine fuel spray simulation test device for high-altitude and cold environments according to any one of claims 1-3, characterized in that: A rectangular plate is welded to each of the two edges of the semi-circular metal plate. Each plate has a threaded hole, which is fastened to the support screw (13).

5. A diesel engine fuel spray simulation test device for high-altitude and cold environments according to any one of claims 1-3, characterized in that: The shape of the impact device (12) is a plane perpendicular to the injector (5), or an inclined surface at a 45° angle to the injector (5), or an arc surface closer to the cylinder side wall.

6. A diesel engine fuel spray simulation test device for high-altitude and cold-weather environments according to any one of claims 1-3, characterized in that: The fuel storage and pretreatment equipment (1) has a built-in fuel storage tank and a device for adjusting the fuel according to preset temperature and pressure.

7. A diesel engine fuel spray simulation test device for high-altitude and cold-weather environments according to any one of claims 1-3, characterized in that: The bracket (2) consists of a horizontal bar and a vertical bar at right angles. The horizontal bar and the vertical bar are connected by a thread, and the height of the horizontal bar is adjusted by the thread. There is a clamp at the end of the horizontal bar for clamping and fixing the injector (5). The clamp and the horizontal bar are connected by a bearing, and the angle of the clamp can be adjusted.

8. A diesel engine fuel spray simulation test device for high-altitude and cold-weather environments according to any one of claims 1-3, characterized in that: The environmental cavity (10) is cylindrical and made of two layers of transparent quartz glass. Except for the passage range required for the operation of the high-speed camera (8) and the light source (9), it is wrapped with heat insulation material to maintain temperature stability. The reserved hole position needs to be sealed with sealing material after the complete set of equipment is installed. An oil mist suction device (17) is installed on the right side of the top surface of the environmental cavity (10). It is turned on after each test shooting to remove the oil mist in the environmental cavity (10).

9. A test method for a diesel engine fuel spray simulation test device for high-altitude and cold-weather environments according to any one of claims 1-8, characterized in that, Includes the following steps: S1 Turn on the high-speed camera (8) and light source (9), adjust the position and parameters, use the marked ruler to calibrate the size, and prepare for shooting; S2 Opens the fuel storage and pretreatment equipment (1) and sets the injection pressure, injection quantity and injection duration; S3 adjusts the pulse width and frequency parameters of the pulse controller (6); After the S4 system reaches the preset injection parameters, click the shooting command of the high-speed camera (8) on the computer (7) and click the pulse controller (6) to control the oil injection; After the S5 shooting is finished, turn on the oil mist removal device (17) to remove the fog; S6 Repeat steps 1-5, performing each experiment three times; S7 acquires image data and performs post-processing.

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