CN115324716A

CN115324716A - Pre-combustion chamber

Info

Publication number: CN115324716A
Application number: CN202211258023.3A
Authority: CN
Inventors: 张海瑞; 李军银; 朱涛; 宿兴东
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2022-11-11
Anticipated expiration: 2042-10-14
Also published as: CN115324716B

Abstract

The embodiment of the application discloses precombustion chamber, including upper portion cavity, middle part cavity and lower part cavity, the diameter of middle part cavity is greater than the diameter of lower part cavity and upper portion cavity, and the volume of middle part cavity is greater than the volume of lower part cavity and upper portion cavity. The middle cavity has larger volume, so that the quality of mixed gas is improved, and the ignition energy is enhanced; the volume of the upper cavity is smaller than that of the middle cavity, the amount of waste gas accumulated by the upper cavity is small, the diameter of the upper cavity is smaller than that of the middle cavity, and the upper cavity extrudes the mixed gas, so that the flow rate of the mixed gas is accelerated, and the waste gas is favorably swept; the diameter of the lower cavity is smaller than that of the middle cavity, the volume of the lower cavity is smaller than that of the middle cavity, high-temperature and high-pressure gas entering the lower cavity from the middle cavity is extruded in the lower cavity, the jet speed is accelerated, the contact time of the high-temperature and high-pressure gas and the lower cavity is shortened, the contact area of the high-temperature and high-pressure gas and the lower cavity is reduced, and the heat transfer loss is reduced.

Description

Pre-combustion chamber

Technical Field

The application relates to the technical field of engines, in particular to a precombustion chamber.

Background

The precombustion chamber is communicated with the main combustion chamber through jet holes. The mixed gas in the main combustion chamber is pressed into the precombustion chamber through the jet hole under the compression action of the piston, and is mixed with the residual waste gas in the precombustion chamber, the spark plug ignites to ignite the mixed gas in the precombustion chamber, high-temperature and high-pressure gas is generated in the precombustion chamber and forms pressure difference with the main combustion chamber, and the high-temperature and high-pressure gas is pushed by the pressure difference to be sprayed into the main combustion chamber in a high-speed jet flow mode to ignite the mixed gas in the main combustion chamber.

The purging effect of the waste gas near the electrode in the pre-combustion chamber influences the success rate of ignition; the ignition energy of the precombustion chamber is increased, so that the injection speed of flame can be improved, and the heat transfer loss is reduced.

Therefore, how to improve the scavenging effect of the precombustion chamber and reduce the heat transfer loss of the precombustion chamber becomes a technical problem to be solved urgently by those skilled in the art.

Disclosure of Invention

The application provides a precombustor to improve the scavenging effect of precombustor, reduce the heat transfer loss of precombustor simultaneously.

In order to achieve the above object, the application provides a precombustion chamber, which includes a precombustion chamber body, wherein a cavity of the precombustion chamber body includes an upper cavity, a middle cavity and a lower cavity, the lower cavity is provided with a jet orifice assembly, the volume of the middle cavity is greater than that of the upper cavity, and the volume of the middle cavity is greater than that of the lower cavity;

the diameter of the middle cavity is larger than that of the upper cavity, the middle cavity is connected with the upper cavity through a first transition fillet,

the diameter of the middle cavity is larger than that of the lower cavity, and the middle cavity is connected with the lower cavity through a second transition fillet.

Preferably, in the precombustor, a radius of the first transition fillet is larger than a radius of the second transition fillet, and the first transition fillet and the second transition fillet are both convex toward an inner wall of the cavity.

Preferably, in the precombustion chamber, the upper cavity is a truncated cone-shaped cavity, the diameter of the lower end of the upper cavity is greater than that of the upper end of the upper cavity, and the lower end of the upper cavity is connected with the upper end of the middle cavity through the first transition fillet.

Preferably, in the precombustion chamber, the middle cavity is a spherical cavity, and the diameter of the upper end of the middle cavity is larger than or equal to that of the lower end of the middle cavity.

Preferably, in the precombustion chamber, the lower cavity is conical, the upper end of the lower cavity is connected with the lower end of the middle cavity through the second transition fillet, and the lower end of the lower cavity is provided with the jet hole assembly.

Preferably, in the precombustor, the height of the middle cavity is greater than the height of the lower cavity, and the height of the lower cavity is greater than the height of the upper cavity.

Preferably, in the precombustion chamber, the nozzle assembly includes a first nozzle hole and a second nozzle hole, the first nozzle hole is opened along an axial direction of the precombustion chamber body and is arranged coaxially with the precombustion chamber body, and the second nozzle hole is opened along a circumferential direction of the precombustion chamber body.

Preferably, in the precombustion chamber, the helical angle of the second nozzle hole is 5 ° to 10 °.

Preferably, in the precombustor, the second nozzle hole has a taper angle of 60 ° to 65 °.

Preferably, in the precombustion chamber, the diameter of the second nozzle hole is 1 mm-2.5 mm.

The utility model provides a precombustion chamber, including upper portion cavity, middle part cavity and lower part cavity, the orifice subassembly is seted up to the lower part cavity, and the volume of middle part cavity is greater than the volume of upper portion cavity, and the volume of middle part cavity is greater than the volume of lower part cavity, and the diameter of middle part cavity is greater than the diameter of upper portion cavity. The middle cavity adopts a larger volume, so that the quality of mixed gas is increased, and the ignition energy is enhanced; because the volume of the upper cavity is smaller than that of the middle cavity, the amount of waste gas accumulated by the upper cavity is small, and meanwhile, the diameter of the upper cavity is smaller than that of the middle cavity, mixed gas enters the upper cavity from the middle cavity, and the upper cavity extrudes the mixed gas, so that the flow velocity of the mixed gas is accelerated, and the waste gas near the electrode can be swept; the volume of the lower cavity is smaller than that of the middle cavity, the diameter of the lower cavity is smaller than that of the middle cavity, high-temperature and high-pressure gas entering the lower cavity from the middle cavity is extruded in the lower cavity, the jet speed is accelerated, the contact time of the high-temperature and high-pressure gas and the lower cavity is shortened, meanwhile, the contact area of the high-temperature and high-pressure gas and the lower cavity is reduced, and the heat transfer loss is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some examples or embodiments of the present application, and that for a person skilled in the art, other drawings can be obtained from the provided drawings without inventive effort, and that the present application can also be applied to other similar scenarios from the provided drawings. Unless otherwise apparent from the context, or otherwise indicated, like reference numbers in the figures refer to the same structure or operation.

FIG. 1 is a schematic structural view of a precombustor of the present application;

FIG. 2 is a schematic view of scavenging streamlines of the prechamber of the present application;

FIG. 3 is a schematic view of flame propagation within the precombustor of the present application.

Wherein:

1. upper cavity, 2, middle cavity, 3, lower part cavity.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant application and are not limiting of the application. The described embodiments are only some embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that, for the convenience of description, only the parts related to the related applications are shown in the drawings. The embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be understood that "system", "apparatus", "unit" and/or "module" as used herein is a method for distinguishing different components, elements, parts or assemblies at different levels. However, other words may be substituted by other expressions if they accomplish the same purpose.

As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements. An element defined by the phrase "comprising one of \ 8230: \ 8230:" does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

In the description of the embodiments herein, "/" means "or" unless otherwise specified, for example, a/B may mean a or B; "and/or" herein is merely an association describing an associated object, and means that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two.

In the following, the terms "first", "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

Flow charts are used herein to illustrate operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, the various steps may be processed in reverse order or simultaneously. Meanwhile, other operations may be added to the processes, or a certain step or several steps of operations may be removed from the processes.

Referring to fig. 1 to 3, some embodiments of the present disclosure disclose a prechamber including a prechamber body, wherein the cavity of the prechamber body includes an upper cavity 1, a middle cavity 2, and a lower cavity 3, wherein the upper cavity 1 is provided with an electrode, the lower cavity 3 is provided with a nozzle assembly, the volume of the middle cavity 2 is greater than the volume of the upper cavity 1, and the volume of the middle cavity 2 is greater than the volume of the lower cavity 3.

In this application, the diameter of middle part cavity 2 is greater than the diameter of upper portion cavity 1, and middle part cavity 2 is connected through first transition fillet with upper portion cavity 1, and the diameter of middle part cavity 2 is greater than the diameter of lower part cavity 3, and middle part cavity 2 is connected through second transition fillet with lower part cavity 3.

Upper portion cavity 1 is connected through first transition fillet with middle part cavity 2, and middle part cavity 2 is connected through second transition fillet with lower part cavity 3 for the inner chamber of antechamber body is smooth inner chamber, does not have right angle or edges and corners, in order to reduce gas energy loss.

The utility model discloses a precombustion chamber, the volume of middle part cavity 2 is greater than the volume of lower part cavity 3, and the volume of middle part cavity 2 is greater than the volume of upper portion cavity 1, and the diameter of middle part cavity 2 is greater than the diameter of lower part cavity 3, and the diameter of middle part cavity 2 is greater than the diameter of upper portion cavity 1. The middle cavity 2 has a larger volume, so that the quality of mixed gas is improved, and the ignition energy is enhanced; because the volume of the upper cavity 1 is smaller than that of the middle cavity 2, the amount of waste gas accumulated in the upper cavity 1 is small, and meanwhile, the diameter of the upper cavity 1 is smaller than that of the middle cavity 2, mixed gas enters the upper cavity 1 from the middle cavity 2, and the upper cavity 1 extrudes the mixed gas, so that the flow rate of the mixed gas is accelerated, and the waste gas near the electrode can be swept; the volume of lower part cavity 3 is less than the volume of middle part cavity 2, and the diameter of lower part cavity 3 is less than the diameter of middle part cavity 2, and the high temperature high pressure gas that gets into lower part cavity 3 from middle part cavity 2 extrudees in lower part cavity 3, and the jet velocity accelerates, shortens the contact time of high temperature high pressure gas and lower part cavity 3, reduces the area of contact of high temperature high pressure gas and lower part cavity 3 simultaneously, reduces heat transfer loss.

In the embodiment that the upper cavity 1 and the lower cavity 3 are cylindrical cavities, compared with the overall cylindrical structure of the precombustion chamber body, the volume of the whole precombustion chamber is increased, and the ignition energy of the precombustion chamber is increased.

During purging, mixed gas enters the upper cavity 1 with a smaller volume from the middle cavity 2 with a larger volume, and the mixed gas is extruded in the upper cavity 1, so that the flowing speed is accelerated, and the scavenging effect of the waste gas of the upper cavity 1 is ensured; high temperature high pressure gas gets into the less lower part cavity 3 of volume from the great middle part cavity 2 of volume, and the gas mixture receives the extrusion at lower part cavity 3, and the velocity of flow accelerates, guarantees the jet velocity, shortens the contact time with lower part cavity 3 simultaneously, reduces heat transfer loss.

The shapes of the upper chamber 1 and the lower chamber 3 are not limited to the cylindrical shape, and may be other shapes.

In some embodiments of the present application, a radius of the first transition fillet is greater than a radius of the second transition fillet.

A large transition fillet reduces the flow losses but increases the height of the prechamber, which results in the same scavenging effect, requiring a larger scavenging energy; correspondingly, a small transition radius increases the flow losses, which results in the same scavenging effect, and also in a need for more scavenging energy.

In order to avoid increasing the height of the precombustion chamber too much and reduce the requirement on scavenging energy, in the present application, a first transition fillet with a relatively large radius and a relatively large radian is adopted at the connecting position of the upper cavity 1 and the middle cavity 2, so as to reduce the energy loss at the connecting position of the upper cavity 1 and the middle cavity 2.

According to the scheme, transition fillets with different sizes are designed, in the scavenging process, airflow rises along the wall surface of the precombustion chamber body, and a first transition fillet with a relatively large radius and a relatively large radian is selected at the connecting position of the upper cavity 1 and the middle cavity 2 with large energy loss so as to reduce the flow loss in the scavenging process; the connecting position of the middle cavity 2 and the lower cavity 3 selects a second transition fillet with relatively smaller radius and relatively smaller radian so as to reduce the overall height of the precombustion chamber to a certain extent and reduce the increase of the height of the precombustion chamber.

As shown in fig. 1-3, the first transition fillet and the second transition fillet are both protruded towards the inner wall of the cavity of the prechamber body to reduce the gas energy loss and prevent dead angles from existing in the cavity.

As shown in figure 1, the lower cavity 3 of the precombustion chamber is conical, and one end of the conical lower cavity 3 with larger diameter is communicated with the middle cavity 2. In the scavenging stage, in the process of organizing airflow, the airflow moves from the lower cavity 3 to the middle cavity 2, the larger the diameter is, the faster the energy attenuation is, the conical lower cavity 3 ensures that in the scavenging process, the intake energy is not attenuated in transition along with the rise of the height of the precombustion chamber, and stronger momentum still exists when the intake energy enters the middle cavity 2.

After ignition, in a flame propagation stage, along with ignition of mixed gas in the precombustion chamber, the pressure in the precombustion chamber is gradually increased, and when high-temperature products pass through the conical lower cavity 3, the speed of the high-temperature products is continuously increased along with continuous reduction of the sectional area of the lower cavity 3, so that the injection speed of flame is finally increased, and the penetration distance of the flame is increased.

In some embodiments of the present application, the upper cavity 1 is a truncated cone-shaped cavity, the diameter of the lower end of the upper cavity 1 is greater than the diameter of the upper end of the upper cavity 1, and the lower end of the upper cavity 1 is connected with the upper end of the middle cavity 2 through a first transition fillet.

The upper cavity 1 is truncated cone-shaped to reduce the increase in the height of the first transition fillet, while the truncated cone-shaped upper cavity 1 with a gradually decreasing diameter can increase the turbulent kinetic energy at the electrode.

In some embodiments of the present application, the middle cavity 2 is a spherical cavity, and the diameter of the upper end of the middle cavity 2 is greater than or equal to the diameter of the lower end of the middle cavity 2. Specifically, the diameter of the upper end of the middle cavity 2 may be equal to the diameter of the lower end of the middle cavity 2, and the diameter of the upper end of the middle cavity 2 may also be greater than the diameter of the lower end of the middle cavity 2.

In the embodiment where the upper end diameter of the middle chamber 2 is larger than the lower end diameter of the middle chamber 2, the mixture forms a vortex in the cavity of the prechamber, rising along the axis of the prechamber, as shown in fig. 2.

The height of the middle cavity 2 is greater than that of the lower cavity 3 to increase the overall volume of the prechamber body 1 to a greater extent.

The height of lower part cavity 3 is greater than the height of upper portion cavity 1, and the height of upper portion cavity 1 is minimum promptly, and this kind of mode of setting not only reduces waste gas at upper portion cavity 1's accumulation, improves the scavenging effect, can improve the extrusion length of high temperature high pressure gas cavity under moreover, guarantees injection velocity.

The height relationship between the middle chamber 2 and the lower chamber 3 is not specifically defined in the present application, and is specifically selected by those skilled in the art according to actual needs.

The utility model discloses a jet orifice subassembly of prechamber includes first jet orifice and second jet orifice, and wherein first jet orifice is seted up along the axis direction of prechamber body and is arranged with the prechamber body is coaxial, and the number of second jet orifice is a plurality of and evenly or unevenly seting up along the circumference of prechamber body.

In other embodiments of the present application, the nozzle assembly includes only second nozzles, and the plurality of second nozzles are uniformly or non-uniformly opened in a circumferential direction of the prechamber.

Preferably, the second jet holes are uniformly distributed along the circumferential direction of the precombustion chamber, so that the uniform distribution of the mixed gas in the precombustion chamber body is improved, and the ignition performance of the main combustion chamber is favorably improved after ignition.

In some embodiments of the present application, the second orifice has a helix angle of 5 ° to 10 °, an aperture of 1 mm to 2.5mm, and a cone angle of 60 ° to 65 °.

The above description is only for the purpose of illustrating the preferred embodiments of the present application and the technical principles applied, and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. The scope of the application referred to in the present application is not limited to the specific combinations of the above-mentioned features, and it is intended to cover other embodiments in which the above-mentioned features or their equivalents are arbitrarily combined without departing from the spirit of the application. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. The precombustion chamber is characterized by comprising a precombustion chamber body, wherein the cavity of the precombustion chamber body comprises an upper cavity (1), a middle cavity (2) and a lower cavity (3), the lower cavity (3) is provided with a spray hole assembly, the volume of the middle cavity (2) is greater than that of the upper cavity (1), and the volume of the middle cavity (2) is greater than that of the lower cavity (3);

the diameter of the middle cavity (2) is larger than that of the upper cavity (1), the middle cavity (2) is connected with the upper cavity (1) through a first transition fillet,

the diameter of the middle cavity (2) is larger than that of the lower cavity (3), and the middle cavity (2) is connected with the lower cavity (3) through a second transition fillet.

2. A prechamber according to claim 1, characterised in that the radius of the first fillet is larger than the radius of the second fillet, both the first and the second fillet being convex towards the inner wall of the cavity.

3. A prechamber according to claim 1, characterised in that the upper cavity (1) is a truncated cone shaped cavity, the diameter of the lower end of the upper cavity (1) being larger than the diameter of the upper end of the upper cavity (1), the lower end of the upper cavity (1) and the upper end of the middle cavity (2) being connected by means of the first transition radius.

4. A prechamber according to claim 3, characterised in that the middle cavity (2) is a spherical cavity, the diameter of the upper end of the middle cavity (2) being larger than or equal to the diameter of the lower end of the middle cavity (2).

5. A prechamber according to claim 4, characterised in that the lower cavity (3) is conical, that the upper end of the lower cavity (3) is connected with the lower end of the middle cavity (2) by means of the second transition radius, and that the lower end of the lower cavity (3) is provided with the jet hole assembly.

6. A prechamber according to any of the claims 1-5, characterised in that the height of the middle chamber (2) is greater than the height of the lower chamber (3), and that the height of the lower chamber (3) is greater than the height of the upper chamber (1).

7. A prechamber according to claim 1, characterised in that the jet assembly comprises a first jet opening, which opens in the direction of the axis of the prechamber body and is arranged coaxially with the prechamber body, and a second jet opening, which opens in the circumferential direction of the prechamber body.

8. The precombustor of claim 7, wherein the helix angle of the second jet orifices is between 5 ° and 10 °.

9. The precombustor of claim 7, wherein the second jet orifices have a taper angle of 60 ° -65 °.

10. The precombustor of claim 7, wherein the second nozzle orifice has an orifice diameter of 1 mm-2.5 mm.