Visual constant volume combustion device for observing jet ignition under the influence of the wall surface

Abstract

This specification discloses a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface, which includes a body, a quartz glass, a glass end cap, a first spark plug, a support column, an active pre-chamber, a second spark plug, an intake / exhaust pipeline, a first direct injection fuel injector, a heating plate, a heating plate pressing plate, an internal temperature sensor, a wall temperature sensor, a passive pre-chamber, and a jet flame impingement mechanism. The overall structure of this device is compact, with a high degree of integration, a large window area and good sealing performance. It can be assembled with a passive pre-chamber with internal visibility, an active pre-chamber with fuel supply, and a jet flame impingement mechanism according to needs to simulate various jet ignition and combustion modes existing in an actual engine, and is convenient for carrying out parametric studies of single factors, which is beneficial to promoting the positive design and research and development of the combustion system of a jet ignition engine.

Description

Technical Field

[0001] The present invention relates to the technical field of internal combustion engine combustion, and more specifically, to a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface. Background Art

[0002] Under the background of "carbon peak and carbon neutrality", as a power conversion device in automobiles, ships, and aviation, the piston internal combustion engine will, on the one hand, continuously break through the thermal efficiency limit, and on the other hand, use renewable low / zero-carbon fuels to achieve high efficiency, cleanliness, and net zero carbonization. Pre-chamber jet ignition is an engine combustion technology that can improve ignition stability and combustion rate and suppress knocking. By injecting a high-speed turbulent jet containing free radicals through the pre-chamber to initiate multi-point rapid combustion in the cylinder, the isochoric degree is increased, thereby the compression ratio can be increased. Active ignition can also expand the lean burn limit and EGR rate, both of which are beneficial to the improvement of thermal efficiency. At the same time, jet ignition is also expected to be applied to engines fueled with alternative fuels such as hydrogen, ammonia, and methanol.

[0003] Scholars at home and abroad have carried out a large number of studies on the mechanism of jet ignition, the influence of various structures and thermal parameters, and engine applications, but there are at least the following deficiencies: the interaction between multiple jets affects the ignition area and effectiveness, and existing research rarely considers the ignition modes under different nozzle combinations; the inner wall surface and nozzle shape of the pre-chamber affect the initial flame and jet morphology, and there is currently a lack of optical experimental analysis and most are limited to conventional configurations; the jet flame collides with the external wall surface, which is directly related to the design of the combustion chamber and piston shape, and its design principle still lacks a theoretical basis; autoignition and knocking can still occur in the jet ignition mode, and introducing active spark ignition at the end can reduce pressure oscillations, but the influence of the interaction between the jet and the laminar flame surface is still unclear; in a dual-fuel direct injection engine, the pre-chamber flame jet can be used to ignite the spray jet of low-reactivity fuel, and its ignition characteristics and heat release law still lack basic research.

[0004] Therefore, there is an urgent need to study an integrated and multi-functional experimental device that can conduct optical visualization research on various jet ignition modes to provide theoretical guidance and data support for the design of the pre-chamber structure, the matching of the combustion chamber, and the in-cylinder combustion regulation of the engine. Summary of the Invention

[0005] This specification provides a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface to overcome at least one technical problem existing in the related art.

[0006] According to an embodiment of the present specification, a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface is provided, including a body, a quartz glass, a glass end cap, a first spark plug, a support column, an active pre-chamber, a second spark plug, an intake / exhaust pipeline, a first direct injection fuel injector, a heating plate, a heating plate pressing plate, an internal temperature sensor, a wall temperature sensor, a passive pre-chamber, and a jet flame impinging mechanism, wherein

[0007] The body is a regular octagonal prism with a cylindrical through-hole reserved in the center of the prism. Circular quartz glasses are respectively arranged at both ends of the through-hole. Glass end caps are arranged on the front and rear sides of the body. The quartz glasses are pressed against both ends of the through-hole of the body by the glass end caps. Each side of the glass end cap is fixedly connected to the body by a preset number of high-strength bolts in the circumferential direction. The space surrounded by the through-hole and the quartz glasses inside the body is the body combustion chamber; a threaded hole for installing the first spark plug is arranged on the lower side of the side surface of the body. The first spark plug extends into the body combustion chamber through the threaded hole on the lower side of the side surface of the body. The lower side of the side surface of the body is fixedly connected to the support column by bolts. The body is erected on the profile bracket through the support column; a threaded hole for installing the active pre-chamber or the second spark plug is arranged on the upper side of the side surface of the body. The axis of the threaded hole on the upper side of the body is collinear with the axis of the threaded hole on the lower side of the body; a threaded hole for installing the intake / exhaust pipeline is arranged on the left side surface of the side surface of the body. The intake / exhaust pipeline is horizontally arranged and communicated to the body combustion chamber; a threaded hole for installing the first direct injection injector is arranged on the right side surface of the side surface of the body. The front end of the first direct injection injector horizontally extends into the body combustion chamber; heating plates and heating plate pressing plates are respectively arranged on the four diagonal side surfaces of the side surface of the body. The heating plate pressing plates are fixedly connected to the side surface of the body by bolts. The heating plates are fixed to the side surface of the body through the heating plate pressing plates. The internal temperature sensor extends into the body combustion chamber. The wall temperature sensor is inserted into the body wall. The internal temperature sensor and the wall temperature sensor are arranged in the heating plate pressing plate on any same side; a detachable passive pre-chamber or a detachable jet flame impingement mechanism is arranged in the body combustion chamber. When both the jet flame impingement mechanism and the passive pre-chamber are arranged in the body combustion chamber, the axis of the jet flame impingement mechanism is collinear with the axis of the passive pre-chamber; the active pre-chamber is arranged in the threaded hole on the upper side of the side surface of the body and includes an adapter, a second direct injection injector, a third spark plug, a pre-chamber cavity and a pre-chamber cap. The adapter is a hexagonal prism with a vertical first through-hole and a non-vertical second through-hole arranged inside. The axis of the first through-hole and the axis of the second through-hole form a preset angle. The prism section where the first through-hole is located is higher than the prism section where the second through-hole is located. The second direct injection injector is arranged in the first through-hole. The third spark plug is arranged in the second through-hole. Threads are arranged in the first through-hole and the second through-hole. The second direct injection injector and the third spark plug are connected to the adapter by threads. The second direct injection injector is reinforced with the adapter by bolts. The lower part of the adapter is communicated with the pre-chamber cavity. The lower part of the pre-chamber cavity is connected with a detachable pre-chamber cap. The pre-chamber cap is provided with jet holes. The pre-chamber cap is connected to the body by threads; the passive pre-chamber is arranged in the body combustion chamber and is a hollow cavity. The front and rear side surfaces are pressed against the quartz glasses. The upper side surface is provided with pre-chamber holes. The lower side surface is a circular arc shape matching the body combustion chamber. The lower side surface is provided with a spark plug threaded hole. The first spark plug extends into the passive pre-chamber cavity through the threaded hole;The jet flame impingement mechanism is arranged in the combustion chamber of the body and is fixedly bonded to the inner wall of the combustion chamber of the body through a heat-resistant adhesive. It includes a support beam, a connecting rod, an impingement plate, bolts and nuts. The support beam is integrally formed in an I shape, horizontally arranged, with a middle cross beam, and two prisms with the same size and a trapezoidal cross section at both ends; the connecting rod is vertically arranged at the midpoint of the cross beam of the support beam. One end of the connecting rod is connected to the support beam through bolts and nuts, and the other end is connected to the impingement plate through bolts and nuts. The jet impingement distance is adjusted by changing the number of sections of the connecting rod. The shape of the impingement plate is flat, concave or swirl-shaped, and the angle of the impingement plate is adjustable.

[0008] Optionally, the device includes the following three assembly methods:

[0009] The first method: Install the second spark plug on the upper side of the side of the body, and install the passive pre-chamber in the combustion chamber of the body.

[0010] The second method: Install the second spark plug on the upper side of the side of the body, and install the jet flame impingement mechanism and the passive pre-chamber in the combustion chamber of the body.

[0011] The third method: Install the active pre-chamber on the upper side of the side of the body, and do not install the jet flame impingement mechanism and the passive pre-chamber in the combustion chamber of the body.

[0012] Optionally, a copper gasket is arranged between the adapter and the threaded hole on the upper side of the body side for pressing and sealing. A cooling water connection port is arranged on the adapter, and an annular cooling water tank is arranged inside the adapter, and a partition is arranged in the annular cooling water tank.

[0013] Optionally, the gap between the passive pre-chamber and the quartz glass is between 0.1 and 0.2 millimeters.

[0014] The beneficial effects of the embodiments of this specification are as follows:

[0015] The embodiments of this specification provide a visualization constant volume combustion device for observing jet ignition under the influence of the wall surface, including a body, a quartz glass, a glass end cover, a first spark plug, a support column, an active pre-chamber, a second spark plug, an intake / exhaust pipeline, a first direct injection fuel injector, a heating plate, a heating plate pressing plate, an internal temperature sensor, a wall surface temperature sensor, a passive pre-chamber and a jet flame impingement mechanism. Three assembly schemes can be realized according to experimental needs, and various jet ignition and combustion modes can be simulated. Using a constant volume combustion bomb to simulate the conditions of the engine combustion chamber, compared with an optical engine and a rapid compressor, it has a simple structure, low cost, a large visible area, is convenient for optical path construction, is convenient for optical diagnostics such as high-speed photography, schlieren / shadow, and laser-induced fluorescence, and the volume is within a reasonable range, which is convenient for controlling the initial temperature and pressure, ensuring the repeatability of the experiment, and improving the experimental efficiency, which is beneficial to the forward design and research and development of the combustion system of the jet ignition engine.

[0016] The innovations of the embodiments of this specification include:

[0017] 1. In this specification, the system is compact in design, diverse in functions, and convenient for disassembly and assembly. It can integrate passive and active pre-chambers with different structures, and a jet flame impingement mechanism. It is also equipped with a transient pressure sensor and an injector, which are used to study the flow, ignition, and combustion characteristics under various jet combustion modes and wall effects. This is one of the innovations of the embodiments of this specification.

[0018] 2. In this specification, the bomb can be assembled with an internal passive pre-chamber, which is pressed tightly by the quartz glass of the bomb on the side. The development of the internal flame, cold jet, and counterflow processes can be observed. Moreover, the shape of the pre-chamber and the parameters of the injection holes can be arbitrarily changed, which is convenient for disassembly, assembly, and replacement. This is one of the innovations of the embodiments of this specification.

[0019] 3. In this specification, the bomb can be assembled with an active pre-chamber, which injects liquid or gaseous fuel through a small-flow direct injection injector, and is equipped with a pressure sensor integrated with the spark plug. The lower half is independently installed, and the structural parameters can be arbitrarily changed. It is fixed by the thread of the original spark plug installation hole, which is convenient for disassembly, assembly, and replacement. This is one of the innovations of the embodiments of this specification.

[0020] 4. In this specification, the bomb can be assembled with a jet flame impingement mechanism in the main combustion chamber. Different-shaped impingement plates are fixed through multiple-section connecting rods and screws. The wall distance and angle are adjustable, which is used to study the influence of the interaction between the reacting jet and the external wall on ignition and combustion, and to guide the design of the engine combustion system. This is one of the innovations of the embodiments of this specification.

[0021] 5. In this specification, the bomb can be assembled with a spark plug on the opposite side of the pre-chamber, which is used to introduce spark ignition at the end wall, and to study the influence of the interaction between the flame jet and the laminar flame surface on flame propagation and detonation. This is one of the innovations of the embodiments of this specification.

[0022] 6. In this specification, the bomb is equipped with a direct injection injector in the engine combustion chamber, which can be used to study the ignition of low-reactivity fuel spray jets by the pre-chamber flame jet, and to provide a basis for the ignition and combustion phase control of dual-fuel engines. This is one of the innovations of the embodiments of this specification. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of this specification or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 Schematic structural diagram of a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface provided in an embodiment of this specification;

[0025] Figure 2 Schematic structural diagram of an active pre - combustion chamber provided in an embodiment of this specification;

[0026] Figure 3 Schematic structural diagram of a passive pre - combustion chamber provided in an embodiment of this specification;

[0027] Figure 4 Schematic structural diagram of a jet flame wall - hitting mechanism provided in an embodiment of this specification;

[0028] Figure 5 Schematic structural diagram of a first assembly method provided in an embodiment of this specification;

[0029] Figure 6 Schematic structural diagram of a second assembly method provided in an embodiment of this specification;

[0030] Figure 7 Schematic structural diagram of a third assembly method provided in an embodiment of this specification. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of this specification will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] It should be noted that the terms "including" and "having" in the embodiments of this specification and any variations thereof are intended to cover non - exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0033] An embodiment of this specification discloses a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface, which will be described in detail below.

[0034] Figure 1 Schematic structural diagram of a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface provided in an embodiment of this specification. As Figure 1As shown, a visualization constant volume combustion device for observing jet ignition under the influence of a wall surface includes a body 1, a quartz glass 2, a glass end cap 3, a first spark plug 4, a support column 5, an active pre-chamber 6, a second spark plug 7, an intake / exhaust pipe 8, a first direct injection fuel injector 9, a heating plate 10, a heating plate pressing plate 11, an internal temperature sensor 12, a wall temperature sensor 13, a passive pre-chamber 14, and a jet flame impingement mechanism 15, where

[0035] The body 1 is a regular octagonal prism with a cylindrical through-hole reserved in the center of the prism. Circular quartz glasses 2 are provided at both ends of the through-hole. Glass end caps 3 are provided on the front and back sides of the body. The quartz glass 2 is pressed against both ends of the through-hole of the body 1 by the glass end caps 3. Each side of the glass end cap 3 is fixedly connected to the body 1 by a preset number of high-strength bolts in the circumferential direction. The space inside the body 1 surrounded by the through-hole and the quartz glass 2 is the body combustion chamber. The body combustion chamber is cylindrical, with a diameter of 100 mm and a longitudinal length of 25 mm.

[0036] In a specific embodiment, a glass sealing gasket is provided between the quartz glass 2 and the body 1, and between the quartz glass 2 and the glass end cap 3. The material of the glass sealing gasket is one of a reinforced graphite composite gasket, a PTFE gasket, and a C-4500 gasket. The material of the quartz glass 2 is JGS1 or JGS2.

[0037] A threaded hole for installing the first spark plug 4 is provided on the lower side of the side surface of the body. The first spark plug 4 extends into the body combustion chamber through the threaded hole on the lower side of the side surface of the body 1. The lower side of the side surface of the body is fixedly connected to the support column 5 by a bolt. The body 1 is mounted on a profile bracket through the support column 5. The constant volume combustion bomb is mounted on a profile bracket through two support columns at the bottom and is fixedly connected by bolts.

[0038] A threaded hole for installing the active pre-chamber 6 or the second spark plug 7 is provided on the upper side of the side surface of the body. The axis of the threaded hole on the upper side of the body is collinear with the axis of the threaded hole on the lower side of the body.

[0039] A threaded hole for installing the intake / exhaust pipe 8 is provided on the left side of the side surface of the body. The intake / exhaust pipe 8 is horizontally arranged and communicates with the body combustion chamber. The end straight-through joint of the intake / exhaust pipe 8 is a G thread or an NPT thread.

[0040] A threaded hole for installing the first direct injection fuel injector 9 is provided on the right side of the side surface of the body. The front end of the first direct injection fuel injector 9 horizontally extends into the body combustion chamber. The first direct injection fuel injector 9 is a GDI multi-hole fuel injector or can be welded into a single hole. The first direct injection fuel injector is installed on the left or right side of the constant volume combustion bomb and is fixed by a pressing platform and bolts. The included angle between the oil spray direction and the jet flame direction is 90°.

[0041] On the four diagonal sides of the body side, there are heating plates 10 and heating plate pressing plates 11 respectively. The heating plate pressing plates 11 are fixedly connected to the body side through bolts, and the heating plates 10 are fixed to the body side through the heating plate pressing plates 11. The material of the heating plate 10 is silicon nitride ceramic, with a single rated power of 400W. Each heating plate pressing plate 11 includes two heating plates 10, and the two heating plates 10 are connected in parallel or in series according to the heating power requirements. There are a total of 8 heating plates, which are fixed by pressing plates and bolts, and the total heating power is optional. The temperature sensor is installed on any one of the four diagonal sides of the body.

[0042] The internal temperature sensor 12 extends into the combustion chamber of the body, and the wall temperature sensor 13 is inserted into the body wall. The internal temperature sensor 12 and the wall temperature sensor 13 are arranged in the heating plate pressing plate 11 on any same side. The internal temperature sensor 12 is a K-type thermocouple or a PT100 thermal resistor. The wall temperature sensor 13 is a K-type thermocouple or a PT100 thermal resistor.

[0043] In the combustion chamber of the body, there is a detachable passive pre-chamber 14 or a detachable jet flame impingement mechanism 15. When both the jet flame impingement mechanism 15 and the passive pre-chamber 14 are arranged in the combustion chamber of the body, the axis of the jet flame impingement mechanism 15 is collinear with the axis of the passive pre-chamber 14.

[0044] Figure 2 It is a schematic structural diagram of the active pre-chamber provided by an embodiment of this specification. As Figure 2 shown, the active pre-chamber 6 is arranged in the threaded hole on the upper side of the body side, and includes an adapter 601, a second direct injection fuel injector 602, a third spark plug 603, a pre-chamber cavity 604, and a pre-chamber cap 605, where

[0045] The adapter 601 is a hexagonal prism, with a vertical first through hole and a non-vertical second through hole arranged inside. The axis of the first through hole and the axis of the second through hole form a preset angle. The prism section where the first through hole is located is higher than the prism section where the second through hole is located. The second direct injection fuel injector 601 is arranged in the first through hole, and the third spark plug 603 is arranged in the second through hole. Threads are arranged in the first through hole and the second through hole. The second direct injection fuel injector 602 and the third spark plug 603 are connected to the adapter 601 through threads. The second direct injection fuel injector 602 is reinforced with the adapter 601 through bolts. The adapter 601 communicates with the pre-chamber cavity 604 below, and the pre-chamber cavity 604 is connected to the detachable pre-chamber cap 605 below. The pre-chamber cap 605 is provided with jet holes 606, and the pre-chamber cap 605 is connected to the body 1 through threads.

[0046] The active prechamber is installed above the constant volume combustion bomb and consists of an injector, a spark plug, an adapter, and a prechamber cap. The injector, spark plug, and adapter are connected by threads. The injector is fixed by a press table and bolts and sealed tightly with a copper gasket. The adapter is provided with an annular cooling water tank, and a partition is provided in the water tank to make the water flow unidirectionally. The prechamber cap is installed independently and connected to the body by threads, and has one or more jet holes.

[0047] The prechamber cavity 604 is composed of two sections of cylinders. The upper section has a larger diameter for sufficient mixing, and the lower section has a smaller diameter for flame acceleration. The direct injection injector used is laser welded into a single hole. The jet holes are generally circular, and can also be rectangular, tapered, etc., and the diameter, length, and angle can be changed arbitrarily.

[0048] In a specific embodiment, a copper gasket is provided between the adapter 601 and the threaded hole on the upper side of the body side for pressing and sealing. The adapter 601 is provided with a cooling water inlet 607, and an annular cooling water tank 608 is provided inside the adapter 601, and a partition is provided in the annular cooling water tank 608.

[0049] Figure 3 This is a schematic structural diagram of the passive prechamber provided by an embodiment of this specification. As Figure 3 shown, the passive prechamber 14 is arranged in the body combustion chamber and is a hollow cavity. The front and rear sides are pressed tightly against the quartz glass 2, the upper side is provided with a prechamber jet hole 1401, the lower side is an arc shape matching the body combustion chamber, the lower side is provided with a spark plug threaded hole 1402, and the first spark plug 4 extends into the passive prechamber cavity through the threaded hole. The passive prechamber is installed below or above the inside of the constant volume combustion bomb, is connected to the spark plug by threads, and the side is pressed and sealed by the quartz glass, and the gap is between 0.1 and 0.2 mm, and has one or more jet holes. The cavity of the passive prechamber is rectangular or other shapes. The jet holes are generally circular, and can also be rectangular, tapered, etc., and the diameter, length, and angle can be changed arbitrarily.

[0050] Figure 4 This is a schematic structural diagram of the jet flame hitting the wall mechanism provided by an embodiment of this specification. As Figure 4 shown, the jet flame hitting the wall mechanism 15 is arranged in the body combustion chamber and is adhesively fixed to the inner wall of the body combustion chamber by a heat-resistant adhesive, and includes a support beam 1501, a connecting rod 1502, a wall-hitting plate 1503, a bolt 1504, and a nut 1505, wherein

[0051] The support beam 1501 is integrally formed in an I shape, is horizontally arranged, has a middle cross beam, and both ends are two prisms with the same size and a trapezoidal cross section.

[0052] The connecting rod 1502 is vertically arranged at the midpoint of the cross beam of the support beam 1501. One end of the connecting rod 1502 is connected to the support beam 1501 through bolts 1504 and nuts 1505, and the other end is connected to the wall hitting plate 1503 through bolts 1504 and nuts 1505. The jet wall hitting distance is adjusted by changing the number of sections of the connecting rod 1502. The shape of the wall hitting plate 1503 is flat, concave or swirl-shaped, and the angle of the wall hitting plate 1503 is adjustable. The connecting rod is one section or multiple sections.

[0053] The installation method of this constant volume combustion device is as follows:

[0054] First, the body 1 is fixed on the profile bracket through the support column 5, and the intake / exhaust pipeline 8, the internal temperature sensor 12, and the wall temperature sensor 13 are connected in sequence. The direct injection fuel injector 9 is fixed through the pressing table and bolts, and eight heating plates 10 are fixed through four heating plate pressing plates 11. Then, according to different experimental schemes, the active prechamber 6, the passive prechamber 14, the jet flame wall hitting mechanism 15, and the spark plug 7 are selectively installed, which will be Figures 5 - 7 introduced separately. Finally, the quartz glass 2, the glass end cover 3, and the sealing gasket are connected to the body 1 through bolts, and the bolts are tightened with a torque of about 15 - 20 N·m.

[0055] In specific implementation, this device includes three assembly methods.

[0056] Figure 5 This is the structural schematic diagram of the first assembly method provided by an embodiment of this specification. As Figure 5 shown, the first method: the second spark plug 7 is installed on the upper side of the side of the body, and the passive prechamber 14 is installed in the combustion chamber of the body.

[0057] The passive prechamber is installed below the bomb. For the structural schematic diagram, see Figure 5 . Both sides of the passive prechamber are pressed tightly against the quartz glass through the prechamber side sealing surface, and the gap is between 0.1 - 0.2 mm, which can prevent damage due to uneven force when contacting the glass, and also makes the air leakage amount negligible, avoiding interference with the schlieren experiment. The lower end surface is arc-shaped and matches the combustion chamber of the body. The lower end is connected and fixed to the first spark plug 4 through the spark plug threaded hole. The spark plug can be equipped with or without a pressure sensor. The prechamber injection holes are one or more, and can have different diameters, lengths, angles, and shapes. The second spark plug 7 with a pressure sensor is installed above the bomb, and the direct injection fuel injector 9 is installed on the right side.

[0058] This method can be used for research on passive jet ignition, research on the interaction between passive jet and flame front, and research on passive jet ignition of spray jet. The following is a brief experimental process:

[0059] Research on passive jet ignition: After the bomb is tested for airtightness, it is evacuated, and gas fuels (such as methane, propane) and air are filled in sequence according to the partial pressure. After standing for a period of time to mix evenly, or a pre-prepared combustible mixture is filled. When heating, it is necessary to wait for the temperature to stabilize after inflation. After the gas distribution is completed, the first spark plug 4 starts to ignite, and at the same time, the camera is triggered to take pictures and the pressure is measured. A laminar flame is generated in the prechamber cavity, and a jet flame is formed through the prechamber orifice 1401. There may be a certain degree of quenching, and then the mixture in the engine combustion chamber is ignited to complete an experiment. Through the images taken by schlieren, direct flame photography, OH* chemiluminescence, etc., as well as the pressure and combustion heat release rate curves, the ignition and combustion processes are comprehensively analyzed.

[0060] Research on the interaction between passive jet and flame front: After the gas distribution is completed as above, both the first spark plug 4 and the second spark plug 7 perform spark ignition. The ignition sequence and time interval can be adjusted through the ECU or the delay signal generator, so that the jet flame collides with the laminar flame front at the corresponding moment, and the image is taken and the pressure is recorded, and then the flame propagation speed, pressure oscillation, heat release rate, etc. are analyzed.

[0061] Research on passive jet ignition of spray jet: After the gas distribution is completed as above, the first spark plug 4 ignites first, and a jet flame is ejected. After a certain time interval, the direct injection injector 9 injects liquid or gas fuel at high pressure. Generally, it is different from the fuel of the premixed gas and has lower activity, so that the jet flame collides with the spray jet at a certain angle and ignites the spray to form diffusion combustion. The time interval between ignition and fuel injection can be adjusted through the ECU or the delay signal generator, and the image is taken and the pressure is recorded, and then the ignition position, ignition time, flame propagation speed, heat release rate, etc. are analyzed.

[0062] Figure 6 This is the structural schematic diagram of the second assembly method provided by an embodiment of this specification. As Figure 6 shown, the second method: The second spark plug 7 is installed on the upper side of the side of the engine body, and the jet flame hitting-wall mechanism 15 and the passive prechamber 14 are installed in the engine combustion chamber of the engine body.

[0063] The jet flame hitting-wall mechanism 15 is installed in the engine combustion chamber of the bomb. The structural schematic diagram is shown in Figure 6 . During installation, first bolt-connect one or more connecting rods 1502 with the support beam 1501 and the hitting-wall plate 1503 according to needs, then apply high-temperature adhesive on the arc surface of the support beam 1501, and adhesively connect the whole to the combustion chamber of the bomb and adjust it to be horizontal. The hitting-wall plate 1503 can also be rotated by a certain angle to change the hitting-wall angle. The second spark plug 7 with a pressure sensor is installed above the bomb, and the passive prechamber 14 and the first spark plug 4 are installed below. The first spark plug 4 may or may not be equipped with a pressure sensor.

[0064] This method can be used for the research on the ignition of the impinging reactive jet. The following is a brief experimental process:

[0065] Perform gas distribution as described above. The first spark plug 4 starts to ignite. Meanwhile, the camera is triggered to take pictures and the pressure is measured. A jet flame with or without quenching is formed through the pre-chamber nozzle 1401, and then it impinges on the impingement plates 1503 with different distances, angles, and shapes, resulting in flow stagnation, and then igniting the mixture. By taking pictures and recording the pressure curve, the ignition location, heat release rate, etc. can be analyzed.

[0066] Figure 7 It is a schematic structural diagram of the third assembly method provided in an embodiment of this specification. As Figure 7 shown, the third method: The active pre-chamber 6 is installed on the upper side of the side of the engine block, and the jet flame impingement mechanism 15 and the passive pre-chamber 14 are not installed in the combustion chamber of the engine block.

[0067] The active pre-chamber 6 is installed above the bomb. The schematic structural diagram is shown in Figure 7 . During installation, first fix the adapter 601 to the engine block 1 with a certain torque through threads and gaskets, and then install the third spark plug 603 with or without a pressure sensor. The second direct injection injector 602 is vertically fixed through the pressing platform and bolts. The bolts are vertically screwed into the bolt holes of the injector pressing platform. Connect the cooling water pipe to the cooling water interface 607, which is connected to the cooling water tank 608 to cool the second direct injection injector 602 and the third spark plug 603. Finally, fix the pre-chamber cap 605 to the original spark plug installation hole above the engine block 1 through threads. The jet nozzle 606 is one or more, and can have different diameters, lengths, angles, and shapes. The first spark plug 4 with a pressure sensor is installed below the bomb, and the first direct injection injector 9 is installed on the right side.

[0068] This method can be used for the research on active jet ignition, the research on the interaction between active jet and flame front, and the research on the ignition of spray jet by active jet. The following is a brief experimental process:

[0069] Research on active jet ignition: Perform gas distribution in the main combustion chamber as described above. Then, according to the required fuel-air equivalence ratio or excess air coefficient of the pre-chamber, inject the same or different liquid or gas fuels into the pre-chamber cavity 604 through the second direct injection injector 602 of the active pre-chamber 6. After the injection ends, after a certain time interval, the third spark plug 603 starts to ignite to form a jet flame, which ignites the mixture in the main combustion chamber. After completing one experiment, analyze the images, pressure, and heat release rate.

[0070] Research on the Interaction between Active Jet and Flame Front: As described above, the air distribution in the main combustion chamber is completed. According to the required fuel-air equivalence ratio, fuel is injected and mixed evenly. Then, the third spark plug 603 and the first spark plug 4 with a pressure sensor conduct spark ignition at different times respectively. The ignition sequence and time interval can be adjusted through the ECU or a delay signal generator, so that the jet flame collides with the laminar flame front at the corresponding moment. By taking pictures and recording the pressure curve, the flame propagation speed, pressure oscillation, heat release rate, etc. can be analyzed.

[0071] Research on Active Jet Ignition of Spray Jet: After the combustion bomb is evacuated and filled with air, according to the required fuel-air equivalence ratios of the main combustion chamber and the pre-chamber, fuel is first injected into the active pre-chamber 6 and mixed evenly. Then, the third spark plug 603 ignites to eject a jet flame. After a certain time interval, the first direct injection fuel injector 9 injects liquid or gaseous fuel at high pressure, which is generally different from the fuel injected into the active pre-chamber 6 and has lower activity, so that the jet flame collides with the spray jet at a certain angle and ignites the spray to form diffusion combustion. The time interval between ignition and fuel injection can be adjusted through the ECU or a delay signal generator. After completing image taking and pressure recording, the ignition position, ignition time, flame propagation speed, heat release rate, etc. can be analyzed.

[0072] Those of ordinary skill in the art can understand that: The drawings are only schematic diagrams of an embodiment, and the modules or processes in the drawings are not necessarily essential for implementing the present invention.

[0073] Those of ordinary skill in the art can understand that: The modules in the device in the embodiment can be distributed in the device of the embodiment according to the description of the embodiment, or can be correspondingly changed and located in one or more devices different from this embodiment. The modules of the above embodiments can be combined into one module, or can be further split into multiple sub-modules.

[0074] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A visualization constant-volume combustion device for observing jet ignition under the influence of a wall surface, characterized in that, It includes a body, a quartz glass, a glass end cap, a first spark plug, a support column, an active pre-chamber, a second spark plug, an intake / exhaust pipe, a first direct injection fuel injector, a heating plate, a heating plate pressing plate, an internal temperature sensor, a wall temperature sensor, a passive pre-chamber, and a jet flame impingement mechanism, where The body is a regular octagonal prism with a cylindrical through-hole reserved in the center of the prism. Circular quartz glasses are respectively arranged at both ends of the through-hole. Glass end caps are arranged on the front and back sides of the body. The quartz glasses are pressed against both ends of the through-hole of the body by the glass end caps. Each side of the glass end cap is fixedly connected to the body by a preset number of high-strength bolts in the circumferential direction. The space surrounded by the through-hole and the quartz glass inside the body is the body combustion chamber; Threaded holes for installing the first spark plug are arranged on the lower side of the side surface of the body. The first spark plug extends into the body combustion chamber through the threaded holes on the lower side of the side surface of the body. The lower side of the side surface of the body is fixedly connected to the support column by bolts. The body is erected on the profile bracket through the support column; Threaded holes for installing the active pre-chamber or the second spark plug are arranged on the upper side of the side surface of the body. The axis of the threaded hole on the upper side of the body is collinear with the axis of the threaded hole on the lower side of the body; Threaded holes for installing the intake / exhaust pipe are arranged on the left side surface of the body. The intake / exhaust pipe is horizontally arranged and communicated to the body combustion chamber; Threaded holes for installing the first direct injection fuel injector are arranged on the right side surface of the body. The front end of the first direct injection fuel injector horizontally extends into the body combustion chamber; Four diagonal side surfaces of the side surface of the body are respectively provided with a heating plate and a heating plate pressing plate. The heating plate pressing plate is fixedly connected to the side surface of the body by bolts. The heating plate is fixed to the side surface of the body through the heating plate pressing plate. The internal temperature sensor extends into the body combustion chamber. The wall temperature sensor is inserted into the body wall. The internal temperature sensor and the wall temperature sensor are arranged in the heating plate pressing plate on any same side surface; A detachable passive pre-chamber or a detachable jet flame impingement mechanism is arranged in the body combustion chamber. When both the jet flame impingement mechanism and the passive pre-chamber are arranged in the body combustion chamber, the axis of the jet flame impingement mechanism is collinear with the axis of the passive pre-chamber; The active pre-chamber is arranged in the threaded hole on the upper side of the side surface of the body and includes an adapter, a second direct injection fuel injector, a third spark plug, a pre-chamber cavity, and a pre-chamber cap, where The adapter is a hexagonal prism with a vertical first through-hole and a non-vertical second through-hole arranged inside. The axis of the first through-hole and the axis of the second through-hole form a preset angle. The prism section where the first through-hole is located is higher than the prism section where the second through-hole is located. The second direct injection fuel injector is arranged in the first through-hole. The third spark plug is arranged in the second through-hole. Threads are arranged in the first through-hole and the second through-hole. The second direct injection fuel injector and the third spark plug are connected to the adapter through threads. The second direct injection fuel injector is reinforced with the adapter by bolts. The lower part of the adapter communicates with the pre-chamber cavity. The lower part of the pre-chamber cavity is connected to a detachable pre-chamber cap. The pre-chamber cap is provided with jet holes. The pre-chamber cap is connected to the body by threads; The passive pre - combustion chamber is arranged in the engine body combustion chamber. It is a hollow cavity. Its front and rear sides are pressed tightly against the quartz glass. The upper side is provided with pre - combustion chamber spray holes. The lower side is an arc shape that matches the engine body combustion chamber. The lower side is provided with a spark plug threaded hole. The first spark plug extends into the cavity of the passive pre - combustion chamber through the threaded hole; The jet flame impingement mechanism is arranged in the engine body combustion chamber and is adhesively fixed to the inner wall of the engine body combustion chamber through a heat - resistant adhesive. It includes a support beam, a connecting rod, an impingement plate, bolts, and nuts, where The support beam is integrally formed in an I - shape and is horizontally arranged. There is a middle cross - beam, and the two ends are two prisms with the same size and a trapezoidal cross - section; The connecting rod is vertically arranged at the mid - point of the cross - beam of the support beam. One end of the connecting rod is connected to the support beam through bolts and nuts, and the other end is connected to the impingement plate through bolts and nuts. The jet impingement distance is adjusted by changing the number of sections of the connecting rod. The shape of the impingement plate is flat or concave or swirl - shaped, and the angle of the impingement plate is adjustable.

2. The device according to claim 1, wherein The said device includes the following three assembly methods: The first method: Install the second spark plug on the upper side of the engine body side, and install the passive pre - combustion chamber in the engine body combustion chamber; The second method: Install the second spark plug on the upper side of the engine body side, and install the jet flame impingement mechanism and the passive pre - combustion chamber in the engine body combustion chamber; The third method: Install the active pre - combustion chamber on the upper side of the engine body side, and do not install the jet flame impingement mechanism and the passive pre - combustion chamber in the engine body combustion chamber.

3. The device according to claim 1, characterized in that A copper gasket is arranged between the adapter and the threaded hole on the upper side of the engine body side for pressing and sealing. The adapter is provided with a cooling water inlet, and an annular cooling water tank is arranged inside the adapter. There are partitions in the annular cooling water tank.

4. The device according to claim 1, characterized in that, The gap between the passive pre - combustion chamber and the quartz glass is between 0.1 and 0.2 millimeters.

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