Jet-induced methanol spray combustion system optical diagnosis device and test method thereof

Abstract

The invention relates to the technical field of internal combustion engines, in particular to a jet-induced methanol spray combustion system optical diagnosis device and a test method thereof, and the methanol spray combustion system optical diagnosis device comprises a methanol supply unit, a constant volume bomb combustion unit, an optical diagnosis unit, a data acquisition and control unit and an air supply unit. Wherein the constant volume bomb combustion unit comprises a constant volume bomb, a second methanol ejector, a spark plug, a glow plug, a pre-combustion chamber, a first methanol ejector, an exhaust electromagnetic valve and a constant volume bomb heating unit. The optical diagnosis unit comprises a first digital high-speed camera, a second digital high-speed camera, a first band-pass filter, a second band-pass filter, a high-speed stroboscopic LED light source, a first window, a second window, a diffusion sheet, a convex lens and a spectroscope. Synchronous high-frequency acquisition of a liquid-phase spray image and a flame image of the pre-combustion chamber jet flow induced methanol spray diffusion combustion system is realized.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine technology, and in particular to an optical diagnostic device and test method for a jet-induced methanol spray combustion system. Background Technology

[0002] With the increasing energy crisis and environmental protection requirements, methanol, as a clean and efficient alternative fuel, is of great significance for the optimization and upgrading of internal combustion engine technology through in-depth research on its combustion characteristics. Pre-combustion chamber jet-induced methanol spray combustion can achieve a rapid and stable combustion process, improve thermal efficiency, reduce emissions, and fully leverage the advantages of methanol fuel.

[0003] Currently, research on the pre-combustion chamber jet-induced methanol spray diffusion combustion process still faces many challenges. Because the combustion process occurs in a confined space and on an extremely short timescale, traditional testing methods struggle to capture the transient evolution characteristics of the combustion process. Optical diagnostic techniques, as non-contact measurement methods, can achieve real-time visual observation of the combustion process, providing an important means for a deeper understanding of the combustion mechanism.

[0004] However, optical diagnostic devices have the following problems when applied to jet-induced methanol spray combustion systems: First, the interaction between the pre-burning jet flame and the main combustion chamber spray is difficult to observe clearly; second, the spray characteristics of methanol fuel differ from those of conventional fuels, requiring a dedicated spray combustion visualization system; and finally, it is difficult to simultaneously acquire liquid-phase spray and combustion images of the jet-induced methanol spray combustion system.

[0005] Therefore, the search for an optical diagnostic device and testing method for jet-induced methanol spray combustion systems has become a research hotspot. Summary of the Invention

[0006] To address at least one of the aforementioned technical problems, the present invention provides an optical diagnostic device and test method for a jet-induced methanol spray combustion system, which can simultaneously acquire liquid-phase spray images and flame images of the pre-combustion chamber jet-induced methanol spray diffusion combustion system.

[0007] In one aspect, the present invention provides an optical diagnostic device for a jet-induced methanol spray combustion system. The optical diagnostic device includes a methanol supply unit, a constant-volume bomb combustion unit, an optical diagnostic unit, a data acquisition and control unit, and an air supply unit. The constant-volume bomb combustion unit includes a constant-volume bomb, the body of which has a through-cavity in a horizontal direction. The optical diagnostic unit is located in the outer region of the cavity of the constant-volume bomb body and includes: a first viewing window connected to one side of the cavity and collinear with the central axis of the cavity; on the central axis of the cavity, a diffuser and a high-speed strobe LED light source are sequentially arranged along the central axis of the cavity in order of distance from the first viewing window; a second viewing window connected to the other side of the cavity and collinear with the central axis of the cavity; on the central axis of the cavity, a convex lens, a beam splitter, a first bandpass filter, and a first digital high-speed camera are sequentially arranged along the central axis of the cavity in order of distance from the second viewing window; the second bandpass filter and the second digital high-speed camera are arranged in a direction perpendicular to the optical axis of the convex lens in order of distance from the convex lens.

[0008] In some embodiments of the present invention, the methanol supply unit includes: a methanol tank, a pneumatic booster pump and a common rail connected in sequence; and / or an air compressor connected to the pneumatic booster pump.

[0009] In some embodiments of the present invention, the constant volume bomb combustion unit further includes: a pre-combustion chamber and a first methanol injector, spaced apart at the top of the constant volume bomb, the first methanol injector being connected to a common rail; a second methanol injector and a spark plug, spaced apart at the top of the pre-combustion chamber, the second methanol injector being connected to the common rail; a glow plug, disposed on the side of the pre-combustion chamber and penetrating its side wall; and / or, a constant volume bomb heater, disposed inside the constant volume bomb; and / or, an exhaust solenoid valve, disposed on the outer side of the constant volume bomb.

[0010] In some embodiments of the present invention, the data acquisition and control unit includes: a pressure sensor disposed on the outer side of the constant volume bomb; a first temperature sensor disposed on the outer side of the pre-combustion chamber and communicating with the interior, for detecting the temperature inside the pre-combustion chamber; a second temperature sensor disposed at a distance from the pressure sensor on the outer side of the constant volume bomb and communicating with the interior, for detecting the temperature inside the constant volume bomb; an ECU (electronic control unit) for receiving the detection data from the pressure sensor, the first temperature sensor, and the second temperature sensor, and for regulating the operating parameters of the methanol supply unit and the constant volume bomb combustion unit; a host computer connected to the ECU; and a transformer connected to both the constant volume bomb and the ECU.

[0011] In some embodiments of the present invention, the air supply unit includes: an air tank connected to a constant volume bomb; a pressure reducing valve disposed at the outlet of the air tank; and an air intake solenoid valve disposed at the air inlet of the constant volume bomb.

[0012] In some embodiments of the present invention, the high-speed strobe LED light source emits monochromatic ultraviolet light with a wavelength of 266nm ± 10nm; and / or, the center wavelength of the first bandpass filter is 266nm and the bandwidth is 20nm, used to filter interference from the emission of methanol combustion light, enabling the first digital high-speed camera to capture the light signal scattered by the liquid methanol spray; and / or, the center wavelength of the second bandpass filter is 431nm and the bandwidth is 10nm, enabling the second digital high-speed camera to capture the emission spectrum of CH* free radicals in the methanol spray combustion flame.

[0013] In another aspect, the present invention provides a test method for the above-mentioned jet-induced methanol spray combustion system optical diagnostic device. The test method includes at least one single cycle. The single cycle includes: starting the air supply unit; adjusting the operating parameters of the constant volume bomb and the pre-combustion chamber in the constant volume bomb combustion unit; starting the methanol supply unit and adjusting the methanol pressure in the supply rail pipe to a predetermined rail pressure; starting the constant volume bomb combustion unit so that the turbulent flame jet enters the constant volume bomb; starting the optical diagnostic unit and coordinating parameter settings through the data acquisition and control unit to simultaneously acquire liquid phase spray images and flame images during the methanol spray diffusion combustion process; after the methanol spray combustion is completed, the exhaust gas in the constant volume bomb is discharged through the exhaust solenoid valve.

[0014] In some embodiments of the present invention, the working pressure adjustment range of the pneumatic booster pump is 40~100MPa in the step of starting the methanol supply unit.

[0015] In some embodiments of the present invention, in the step of starting the constant volume combustion unit, the fuel-air equivalence ratio of the methanol-air mixture in the pre-combustion chamber is 0.7 to 1.1; and / or, the timing of injecting methanol into the pre-combustion chamber... The time period from when methanol enters the pre-combustion chamber to when a homogeneous methanol-air mixture is formed. The moment when the spark plug ignites the methanol-air mixture in the pre-combustion chamber The following conditions must be met: ; and / or, the timing at which the first methanol injector injects methanol into the constant-volume projectile. The moment when the turbulent jet flame in the pre-combustion chamber first appears inside the constant-volume projectile. The injection delay time of the first methanol injector under the set common rail pressure and methanol injection quantity conditions. The following conditions must be met: ; The value range is 3~5s.

[0016] In some embodiments of the present invention, in the step of activating the optical diagnostic unit, the operating frequency adjustment range of the high-speed strobe LED light source, the first digital high-speed camera, and the second digital high-speed camera is 10~200kHz, and the operating frequencies of the three are matched in coordination.

[0017] The technical solution provided by this invention has the following advantages: In the optical diagnostic device and test method of the jet-induced methanol spray combustion system of this invention, the methanol supply unit, the constant volume bomb combustion unit, the optical diagnostic unit, the data acquisition and control unit, and the air supply unit work together (specifically, the data acquisition and control unit controls the temperature and pressure inside the constant volume bomb, the pressure and temperature inside the pre-combustion chamber, and simultaneously synchronizes the injection timing and pulse width of methanol inside the constant volume bomb, the injection timing and pulse width of methanol inside the pre-combustion chamber, the ignition timing of the spark plug inside the pre-combustion chamber, the activation timing of the high-speed strobe LED light source, the activation timing of the first digital high-speed camera, and the activation timing of the second digital high-speed camera). The beam splitter in the optical diagnostic unit splits the pulsed light wave emitted by the high-speed strobe LED light source into two beams. On one hand, the light that passes through the convex lens in a straight line passes through the first bandpass filter and enters the first digital high-speed camera to obtain a time-varying image of the methanol liquid phase spray. On the other hand, the reflected light passes through the second bandpass filter and enters the second digital high-speed camera to obtain a time-varying image of the methanol combustion flame. This achieves synchronous high-frequency acquisition of liquid phase spray images and combustion flame images of the pre-combustion chamber jet-induced methanol spray diffusion combustion system, which helps to clarify the interaction law between spray development and combustion process, and provides strong data support for the analysis and design of methanol engine combustion systems. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of an optical diagnostic device for a jet-induced methanol spray combustion system according to an embodiment of the present invention; Figure label: 1-Methanol tank, 2-Air compressor, 3-Pneumatic booster pump, 4-High-pressure methanol pipe, 5-Common rail pipe, 6-Volume control bomb, 7-Second methanol injector, 8-Spark plug, 9-Glow plug, 10-Pre-combustion chamber, 11-First methanol injector, 12-Host computer, 13-ECU electronic control unit, 14-First digital high-speed camera, 15-Second digital high-speed camera, 16-First bandpass filter, 17-Second bandpass filter, 18-High-speed strobe LED light source, 19-First viewing window, 20-Second viewing window, 21-Diffuser, 22-Convex lens, 23-Beam splitter, 24-Air tank, 25-Pressure reducing valve, 26-Intake solenoid valve, 27-Exhaust solenoid valve, 28-Volume control bomb heater, 29-Pressure sensor, 30-First temperature sensor, 31-Second temperature sensor, 32-Transformer. Detailed Implementation

[0021] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0023] According to an embodiment of the present invention, an optical diagnostic device for a jet-induced methanol spray combustion system is provided, the schematic diagram of which is shown below. Figure 1 .like Figure 1 As shown, the optical diagnostic device for the methanol spray combustion system includes a methanol supply unit, a constant-volume bomb combustion unit, an optical diagnostic unit, a data acquisition and control unit, and an air supply unit. The methanol supply unit includes a methanol tank 1, an air compressor 2, a pneumatic booster pump 3, a high-pressure methanol pipe 4, and a common rail pipe 5. The constant-volume bomb combustion unit includes a constant-volume bomb 6, a second methanol injector 7, a spark plug 8, a glow plug 9, a pre-combustion chamber 10, a first methanol injector 11, an exhaust solenoid valve 27, and a constant-volume bomb heater 28. The optical diagnostic unit includes a first digital high-speed camera 14, a second digital high-speed camera 15, a first bandpass filter 16, a second bandpass filter 17, a high-speed strobe LED light source 18, a first viewing window 19, a second viewing window 20, a diffuser 21, a convex lens 22, and a beam splitter 23. The data acquisition and control unit includes a host computer 12, an ECU electronic control unit 13, a pressure sensor 29, a first temperature sensor 30, a second temperature sensor 31, and a transformer 32. The air supply unit includes an air tank 24, a pressure reducing valve 25, and an intake solenoid valve 26.

[0024] In some embodiments of the present invention, such as Figure 1 As shown, in the methanol supply unit, the methanol tank 1, the pneumatic booster pump 3 and the common rail 5 are connected by a high-pressure methanol pipe 4. The air compressor 2 is connected to the pneumatic booster pump 3 through the high-pressure methanol pipe 4.

[0025] In some embodiments of the present invention, such as Figure 1 As shown, in the constant volume bomb combustion unit, the first methanol injector 11 and the pre-combustion chamber 10 are installed on the top of the constant volume bomb 6, the second methanol injector 7, the spark plug 8 and the first temperature sensor 30 are installed in the pre-combustion chamber 10, and the bottom of the pre-combustion chamber 10 is provided with a jet hole that communicates with the constant volume bomb 6; the air tank 24 is connected to the constant volume bomb 6 through an air pipeline, wherein the air pipeline is provided with a pressure reducing valve 25 and an air intake solenoid valve 26, and the constant volume bomb 6 is equipped with a pressure sensor 29 and a second temperature sensor 31; the body of the constant volume bomb 6 is provided with a cavity penetrating the body along its horizontal direction.

[0026] In some embodiments of the present invention, such as Figure 1 As shown, in the optical diagnostic unit, the first window 19 and the second window 20 are disposed on both sides of the cavity of the constant-volume projectile 6, and both the first window 19 and the second window 20 are disposed in the outer region of the cavity of the constant-volume projectile 6. The pulsed light wave emitted by the high-speed strobe LED light source 18 enters the constant-volume projectile 6 through the diffuser 21 and the first window 19. After penetrating the methanol spray flame, it passes through the second window 20, the convex lens 22 and the beam splitter 23, and is split into two beams. The light that passes through the convex lens 22 in a straight line enters the first digital high-speed camera 14 through the first bandpass filter 16 to obtain a time-varying image of the methanol liquid phase spray, while the reflected light enters the second digital high-speed camera 15 through the second bandpass filter 17 to obtain a time-varying image of the methanol combustion flame, thereby realizing real-time, synchronous, and high-frequency imaging of the methanol liquid phase spray and combustion flame.

[0027] In some embodiments of the present invention, the data measured by the pressure sensor, the first temperature sensor, and the second temperature sensor are transmitted to the ECU (Electronic Control Unit). The host computer issues instructions to the ECU according to the experimental conditions to control the operation of the intake solenoid valve, the transformer, the spark plug, the first methanol injector, and the second methanol injector, thereby controlling the pressure and temperature in the pre-combustion chamber and the constant volume cartridge, as well as controlling the injection timing and pulse width of the first and second methanol injectors, and controlling the spark plug ignition timing.

[0028] In some embodiments of the present invention, the high-speed strobe LED light source emits monochromatic ultraviolet light with a wavelength of 266nm ± 10nm. The center wavelength of the first bandpass filter is 266nm and the bandwidth is 20nm, which is used to filter the influence of methanol combustion light emission, so that the first digital high-speed camera can capture the emitted light signal after being scattered by the liquid methanol spray. The center wavelength of the second bandpass filter is 431nm and the bandwidth is 10nm, so that the second digital high-speed camera can capture the emission spectrum of CH* free radicals in the methanol spray combustion flame, thereby locating the reaction zone.

[0029] In some embodiments of the present invention, the nozzle of the first methanol injector is a double-layer nozzle structure with an upper nozzle and a lower nozzle; wherein the upper nozzle and the lower nozzle have the same diameter, the lower nozzle is symmetrically and uniformly distributed 360° around the nozzle of the first methanol injector, and the upper nozzle is asymmetrically and unilaterally distributed 180° around the nozzle of the first methanol injector.

[0030] According to an embodiment of the present invention, a test method for the above-described optical diagnostic device for a methanol spray combustion system is provided, comprising the following steps: S1: Open the pressure reducing valve of the air tank and set the target value of the pressure reducing valve to a level 1 MPa higher than the target pressure inside the constant volume bomb; the function of the air tank is to provide high-pressure air; S2: The host computer sends action commands to the intake solenoid valve and transformer through the ECU electronic control unit to inflate and heat the constant volume bomb, so that the air pressure and temperature inside the constant volume bomb reach the target value; the host computer sends action commands to the glow plug through the ECU electronic control unit to heat the air in the pre-combustion chamber, so that the air temperature in the pre-combustion chamber reaches the target value. S3: Turn on the air compressor and pneumatic booster pump to pump high-pressure methanol into the common rail, so that the methanol pressure in the common rail reaches the predetermined rail pressure. S4: In At a certain moment, the host computer sends an action command to the second methanol injector through the ECU electronic control unit, injecting a certain amount of methanol into the pre-combustion chamber. After a certain time, methanol evaporates in the pre-combustion chamber and forms a homogeneous methanol-air mixture; At any moment, the host computer sends an ignition command to the spark plug through the ECU electronic control unit, igniting the methanol-air mixture in the pre-combustion chamber. The combustion of the methanol-air mixture in the pre-combustion chamber causes the pressure in the pre-combustion chamber to rise sharply, thereby forming a high-speed turbulent flame jet, which enters the constant volume bomb through the nozzle of the pre-combustion chamber. S5: In At any given moment, the host computer sends synchronous action commands to the first methanol injector, the high-speed strobe LED light source, the first digital high-speed camera, and the second digital high-speed camera via the ECU electronic control unit. This commands control the first methanol injector to begin high-pressure methanol injection into the constant-volume projectile, forming a methanol spray. The host computer also controls the high-speed strobe LED light source, the first digital high-speed camera, and the second digital high-speed camera to start working synchronously at the same frequency. This allows the first digital high-speed camera to acquire time-varying images of the methanol spray, and the second digital high-speed camera to acquire time-varying images of the distribution of *CH free radicals in the methanol flame. S6: After the methanol spray diffusion combustion is completed, the host computer sends an action command to the constant volume bomb exhaust valve through the ECU electronic control unit to discharge the exhaust gas in the constant volume bomb, completing a single cycle. At the same time, it controls the intake solenoid valve to deliver fresh air to the constant volume bomb to purge it once, preparing for the next cycle of spray combustion test.

[0031] In some embodiments of the present invention, in step S3, the working pressure adjustment range of the pneumatic booster pump is 40~100MPa.

[0032] In some embodiments of the present invention, in step S4, the air-fuel equivalence ratio of the methanol-air mixture in the pre-combustion chamber is adjusted within the range of 0.7 to 1.1.

[0033] In some embodiments of the present invention, in steps S4 and S5, , and The relationship is as follows: ; The value range is 3 to 5 seconds; , and The relationship is as follows: ;in, The value is determined through a single, independent high-speed photography experiment of pre-combustion chamber spraying, ignition, and combustion visualization (i.e., a single cycle). For example, the moment when the turbulent jet flame in the pre-combustion chamber first appears inside the constant-volume projectile is... Under the conditions of rail pressure and methanol injection rate in the common rail, the injection delay time of the first methanol injector is: ,but The value is This allows the turbulent flame jet in the pre-combustion chamber to collide with the methanol spray in the constant-volume bomb within a suitable time window, thereby inducing ignition of the turbulent flame jet of the high-pressure methanol spray.

[0034] In some embodiments of the present invention, the operating frequency adjustment range of the high-speed strobe LED light source, the first digital high-speed camera, and the second digital high-speed camera is 10~200kHz.

[0035] In summary, the optical diagnostic device and test method for the jet-induced methanol spray combustion system of this invention, through the synergistic effect between the methanol supply unit, the constant volume bomb combustion unit, the optical diagnostic unit, the data acquisition and control unit, and the air supply unit, achieves synchronous high-frequency acquisition of liquid phase spray images and flame images of the jet-induced methanol spray diffusion combustion system in the pre-combustion chamber. This provides strong data support for the analysis and design of the jet-induced combustion system of methanol engines.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0037] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An optical diagnostic device for a jet-induced methanol spray combustion system, characterized in that, the optical diagnostic device for the methanol spray combustion system comprises a methanol supply unit, a constant volume bomb combustion unit, an optical diagnostic unit, a data acquisition and control unit, and an air supply unit; the constant volume bomb combustion unit comprises: a constant volume bomb (6) having a cavity through the body in the horizontal direction; the optical diagnostic unit is arranged outside the cavity of the constant volume bomb (6) body and comprises: a first window (19) connected to one side of the cavity of the constant volume bomb (6) body and collinear with the central axis of the cavity, on the central axis of the cavity, a diffusion sheet (21) and a high-speed stroboscopic LED light source (18) are arranged in sequence on the central axis of the cavity along the order from near to far from the first window (19); a second window (20) connected to the other side of the cavity of the constant volume bomb (6) body and collinear with the central axis of the cavity, on the central axis of the cavity, a convex lens (22), a beam splitter (23), a first band-pass filter (16), and a first digital high-speed camera (14) are arranged in sequence along the order from near to far from the second window (20); a second band-pass filter (17) and a second digital high-speed camera (15) are arranged in sequence along the order from near to far from the convex lens (22) in a direction perpendicular to the optical axis of the convex lens (22).

2. The optical diagnostic apparatus for a fluidic-induced methanol spray combustion system of claim 1, wherein the methanol supply unit comprises: a methanol tank (1), a pneumatic booster pump (3), and a common rail pipe (5) connected in sequence; and / or, an air compressor (2) connected to the pneumatic booster pump (3).

3. The optical diagnostic apparatus for a fluidic-induced methanol spray combustion system of claim 1, wherein the constant volume bomb combustion unit further comprises: a pre-chamber (10) and a first methanol injector (11) arranged at the top of the constant volume bomb (6), the first methanol injector (11) being connected to the common rail pipe (5); a second methanol injector (7) and a spark plug (8) arranged at the top of the pre-chamber (10), the second methanol injector (7) being connected to the common rail pipe (5); an electric heating plug (9) arranged on the side of the pre-chamber (10) and penetrating the side wall thereof; and / or, a constant volume bomb heater (28) arranged inside the constant volume bomb (6); and / or, an exhaust electromagnetic valve (27) arranged on the outside of the constant volume bomb (6).

4. The optical diagnostic apparatus for a fluidic-induced methanol spray combustion system of claim 1, wherein, the data acquisition and control unit comprises: a pressure sensor (29) arranged on the outside of the constant volume bomb (6); a first temperature sensor (30) arranged on the outside of the pre-chamber (10) and penetrating the inside, for detecting the temperature inside the pre-chamber; a second temperature sensor (31) arranged on the outside of the constant volume bomb (6) and penetrating the inside, for detecting the temperature inside the constant volume bomb; an ECU electronic control unit (13) for receiving the detection data of the pressure sensor (29), the first temperature sensor (30), and the second temperature sensor (31), and regulating the operating parameters of the methanol supply unit and the constant volume bomb combustion unit; a host computer (12) connected to the ECU electronic control unit (13); a transformer (32) connected to the constant volume bomb (6) and the ECU electronic control unit (13), respectively.

5. The optical diagnostic apparatus for a fluidic-induced methanol spray combustion system of claim 1, wherein, the air supply unit comprises: an air tank (24) connected to the constant volume bomb (6); a pressure reducing valve (25) arranged at the outlet of the air tank (24); an air inlet solenoid valve (26) arranged at the air inlet of the constant volume bomb (6).

6. The optical diagnostic device of the jet-induced methanol spray combustion system according to claim 1, wherein the high-speed stroboscopic LED light source emits monochromatic ultraviolet light with a wavelength of 266 nm ± 10 nm; and / or, the first band-pass filter has a center wavelength of 266 nm and a bandwidth of 20 nm, and is used to filter the interference of methanol combustion luminescence, so that the first digital high-speed camera can capture the light signal scattered by the liquid-phase methanol spray; and / or, the second band-pass filter has a center wavelength of 431 nm and a bandwidth of 10 nm, so that the second digital high-speed camera can capture the emission spectrum of CH* free radicals in the methanol spray combustion flame.

7. A test method for the optical diagnostic device of the jet-induced methanol spray combustion system according to any one of claims 1-6, wherein the test method comprises at least one single cycle, and the single cycle comprises: starting the air supply unit; adjusting the operating parameters of the constant volume bomb and the pre-chamber in the constant volume bomb combustion unit; starting the methanol supply unit and adjusting the methanol pressure in the supply rail to a predetermined rail pressure; starting the constant volume bomb combustion unit so that the turbulent flame jet enters the constant volume bomb; starting the optical diagnostic unit and synchronously collecting the liquid-phase spray image and the flame image during the methanol spray diffusion combustion process through the parameter coordination setting of the data acquisition and control unit; after the methanol spray combustion is completed, the exhaust gas in the constant volume bomb is discharged through the exhaust solenoid valve. in the step of starting the methanol supply unit, the working pressure of the pneumatic booster pump is adjusted in the range of 40-100 MPa. in the step of starting the constant volume combustion unit, 8. The test method of the optical diagnostic apparatus for a fluidic-induced methanol spray combustion system according to claim 7, characterized in that, the fuel-air equivalence ratio of the methanol-air mixture in the pre-chamber is 0.7-1.1; in the step of starting the optical diagnostic unit, 9. The test method of the optical diagnostic apparatus for the fluidic-induced methanol spray combustion system according to claim 7, characterized in that, the working frequency of the high-speed stroboscopic LED light source, the first digital high-speed camera and the second digital high-speed camera is adjusted in the range of 10-200 kHz, and the working frequencies of the three are coordinated and matched. ​ and / or the time at which methanol is injected into the prechamber the time period during which methanol enters the prechamber to form a homogeneous methanol-air mixture the time at which the spark plug ignites the methanol-air mixture in the prechamber satisfies: ; and / or the time at which the first methanol injector injects methanol into the constant volume bomb , the time at which the pre-chamber turbulent jet flame first appears in the constant volume bomb , the injection delay time of the first methanol injector under the set rail pressure and methanol injection amount conditions of the common rail pipe satisfy: ; The value range is 3~5s.

10. The test method of the optical diagnostic apparatus for a fluidic-induced methanol spray combustion system according to claim 7, characterized in that, ​ ​

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