阅读说明：本技术 燃烧系统及具有其的燃气发动机 (Combustion system and gas engine with same ) 是由 王晓艳 贾德民 郝彩红 李雯霖 于 2021-09-02 设计创作，主要内容包括：本发明属于燃气发动机技术领域,本发明提出了一种燃烧系统和一种具有其的燃气发动机,本发明的第一方面提出了一种燃烧系统,用于燃气发动机,包括缸盖、缸套和设于缸套中的活塞,活塞的顶面、缸套的内壁面和缸盖的底面之间形成有燃烧室,活塞的顶面设有凹坑,凹坑的至少部分轴向截面为半椭圆形,当活塞运行至上止点时,活塞的顶面所在的平面与缸盖的底面之间形成燃烧腔,燃烧腔的至少部分轴向截面为梯形,凹坑的半椭圆形轴向截面的外切六边形与半椭圆形轴向截面相切的部分为第一平面,燃烧腔的梯形轴向截面与第一平面能够组合形成六边形平面。该燃烧系统具有根据滚流流动最外围椭圆迹线设计燃烧室,便于滚流的形成,提高了发动机的热效率。(The invention belongs to the technical field of gas engines, and provides a combustion system and a gas engine with the same. The combustion system is provided with the combustion chamber designed according to the elliptic trace of the outermost periphery of the tumble flow, so that the tumble flow is convenient to form, and the heat efficiency of the engine is improved.)

1. The utility model provides a combustion system, is used for gas engine, its characterized in that, includes cylinder cap, cylinder liner and locates piston in the cylinder liner, the top surface of piston, the internal face of cylinder liner with be formed with the combustion chamber between the bottom surface of cylinder cap, the top surface of piston is equipped with the pit, at least part axial cross-section of pit is semiellipse shape, works as when the piston moves to the top dead center, the plane at the top surface place of piston with form the combustion chamber between the bottom surface of cylinder cap, at least part axial cross-section of combustion chamber is trapezoidal, the circumscribed hexagon of the semiellipse shape axial cross-section of pit with the tangent part of semiellipse shape axial cross-section is the first plane, the trapezoidal axial cross-section of combustion chamber with the first plane can make up and form the hexagon plane.

2. The combustion system of claim 1 wherein the trapezoidal axial cross-section of the combustion chamber and the semi-elliptical axial cross-section of the dimple are symmetrical about the top surface of the piston.

3. The combustion system of claim 1 wherein the length of the major axis of the semi-elliptical axial cross-section of the dimple is between 0.7 and 0.9 times the inner diameter of the liner.

4. The combustion system of claim 2 wherein the sum of the height of the trapezoidal axial cross-section of the combustion chamber and the height of the semi-elliptical axial cross-section of the dimple is 0.5 to 0.75 times the inner diameter of the liner.

5. The combustion system of claim 2, wherein the combustion chamber comprises a first chamber and a second chamber, the axial cross section of the first chamber is symmetrical to the first plane with respect to the top surface of the piston, the bottom of the second chamber is communicated with the first chamber, and a spark plug mounting hole is formed in the position, corresponding to the top of the second chamber, of the cylinder head.

6. The combustion system of claim 5, wherein a difference between an axial length of the first cavity and an axial length of the second cavity is greater than 3 millimeters.

7. The combustion system as claimed in any one of claims 1 to 6, wherein one or two inlet ports and one or two exhaust ports are provided on the bottom surface of the cylinder head, the number of the inlet ports and the exhaust ports is equal, the inlet ports and the exhaust ports are respectively provided on two sides of the axis of the piston, the inlet ports and the exhaust ports are symmetrical about the axis of the piston, an arc-shaped transition structure is provided at the junction of the pit and the top surface of the piston, the arc-shaped transition structure is provided corresponding to the exhaust ports, and the arc-shaped transition structure is tangent to the pit.

8. The combustion system of claim 7, wherein the arc radius of the curved transition structure is 0.2 to 1.2 times the diameter of the dimple.

9. The combustion system of any one of claims 1 to 6 wherein the portion of the top face of the piston corresponding to the inlet port opening is planar.

10. A gas engine comprising a combustion system according to any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of gas engines, and particularly relates to a combustion system. The invention also relates to a gas engine.

Background

This section provides background information related to the present disclosure only and is not necessarily prior art.

With the global resource shortage and the increasingly prominent environmental problems, the requirements of the world on the automobile industry are gradually increased, and how to improve the resource utilization rate and how to reduce the emission becomes a primary problem. In order to reduce the dependence of automobiles on increasingly short petroleum-based fuels, China is implementing an energy diversification strategy, and natural gas is being used as a clean fuel in a large amount on engines. However, natural gas has the disadvantages of high ignition temperature, low flame propagation speed and the like, so that the natural gas engine has long combustion duration, and the problems of high exhaust temperature, low thermal efficiency, large combustion cycle variation and the like are caused, and therefore, optimizing the in-cylinder combustion process and improving the combustion speed are important for the spark ignition type natural gas engine. The traditional natural gas engine is mostly modified on the basis of a diesel engine, the air intake of the traditional natural gas engine is mostly formed into vortex, and the vortex is difficult to form in-cylinder turbulent kinetic energy at the end of compression, so that the improvement of the thermal efficiency of the natural gas engine is limited. And the tumble flow has less momentum attenuation in the compression process and can be stored to the end of a compression stroke, when the piston approaches a top dead center, the large-scale tumble flow is broken into numerous small-scale vortexes, so that the turbulence intensity and the turbulence kinetic energy are increased, the flame propagation rate is favorably improved, and the engine performance is improved. Although the existing combustion system for strengthening the tumble flow of the gas engine can increase the tumble flow and accelerate the combustion speed within a certain range on the premise of not greatly changing the structure of the engine, the structure is limited, and the formation of the tumble flow cannot be obviously improved, so that the gain of the combustion system is limited.

Disclosure of Invention

The invention aims to at least solve the problem of poor tumble generation effect of a gas engine in the prior art, and the aim is realized by the following technical scheme:

the invention provides a combustion system for a gas engine, which comprises a cylinder cover, a cylinder sleeve and a piston arranged in the cylinder sleeve, wherein a combustion chamber is formed among the top surface of the piston, the inner wall surface of the cylinder sleeve and the bottom surface of the cylinder cover, the top surface of the piston is provided with a pit, at least part of the axial section of the pit is semi-elliptical, when the piston runs to the top dead center, a combustion cavity is formed between the plane of the top surface of the piston and the bottom surface of the cylinder cover, at least part of the axial section of the combustion cavity is trapezoidal, the part of the semi-elliptical axial section of the pit, which is tangent to the semi-elliptical axial section, is a first plane, and the trapezoidal axial section of the combustion cavity and the first plane can be combined to form a hexagonal plane.

The combustion system provided by the invention has the advantages that the combustion chamber is designed according to the elliptic trace of the outermost periphery of the tumble flow, the combustion chamber between the cylinder cover and the piston is designed according to the elliptic trace of the outermost periphery of the tumble flow, the virtual ellipse is taken as a design reference, the smooth flow of gas entering the cylinder is ensured, the tumble flow is convenient to form, the wall surface heat transfer is reduced, the thermal efficiency is improved, the combustion chamber has a compact structure, the heat dissipation area is small, the airflow movement in the cylinder is favorably organized, the rapid and complete combustion of fuel is realized, and the purposes of improving the combustion speed of the gas engine and improving the thermal efficiency are finally achieved.

In addition, the combustion system according to the invention may also have the following additional technical features:

in some embodiments of the invention, the trapezoidal axial cross-section of the combustion chamber and the semi-elliptical axial cross-section of the pocket are symmetrical about the top surface of the piston.

In some embodiments of the invention, the length of the major axis of the semi-elliptical axial cross-section of the dimple is between 0.7 and 0.9 times the inner diameter of the liner.

In some embodiments of the invention, the sum of the height of the trapezoidal axial section of the combustion chamber and the height of the semi-elliptical axial section of the dimple is 0.5 to 0.75 times the inner diameter of the liner.

In some embodiments of the present invention, the combustion chamber includes a first chamber and a second chamber, an axial cross section of the first chamber and the first plane are symmetrical with respect to the top surface of the piston, a bottom of the second chamber is communicated with the first chamber, and a spark plug mounting hole is provided in a position of the cylinder head corresponding to a top of the second chamber.

In some embodiments of the invention, the difference between the axial length of the first cavity and the axial length of the second cavity is greater than 3 millimeters.

In some embodiments of the present invention, one or two air inlet ports and one or two air outlet ports are disposed on the bottom surface of the cylinder cover, the number of the air inlet ports is equal to that of the air outlet ports, the air inlet ports and the air outlet ports are respectively disposed on two sides of the axis of the piston, the air inlet ports and the air outlet ports are symmetrical with respect to the axis of the piston, an arc-shaped transition structure is disposed at a connection portion between the concave pit and the top surface of the piston, the arc-shaped transition structure is disposed corresponding to the air outlet ports, and the arc-shaped transition structure is tangential to the concave pit.

In some embodiments of the invention, the arc radius of the arc transition structure is 0.2 to 1.2 times the diameter of the dimple.

In some embodiments of the present invention, a portion of the top surface of the piston corresponding to the air inlet port is a plane.

A second aspect of the present invention provides a gas engine characterised by comprising a combustion system which is an engine water jacket according to the first aspect of the present invention.

The gas engine proposed by the second aspect of the present invention has the same advantageous effects as the combustion system proposed by the first aspect of the present invention, and thus, the description thereof is omitted.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like parts are designated by like reference numerals throughout the drawings. In the drawings:

FIG. 1 schematically illustrates a schematic structural view of a combustion system according to an embodiment of the invention;

the reference symbols in the drawings denote the following:

10: cylinder liner, 11: piston, 12: pits, 13: combustion chamber, 14: spark plug, 15: inlet port, 16: exhaust port opening, 17: intake valves, 18: exhaust valve, 19: an arc transition structure.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be used.

Although the terms, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "second" and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, an element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For convenience of description, spatially relative terms, such as "inner", "outer", "inner", "side", "lower", "below", "upper", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in fig. 1, a first aspect of the present invention provides a combustion system for a gas engine, including a cylinder cover, a cylinder sleeve 10, and a piston 11 disposed in the cylinder sleeve 10, a combustion chamber is formed between a top surface of the piston 11, an inner wall surface of the cylinder sleeve 10, and a bottom surface of the cylinder cover, a pit 12 is disposed on the top surface of the piston 11, at least a portion of an axial cross section of the pit 12 is a semi-elliptical shape, when the piston 11 moves to a top dead center, a combustion chamber 13 is formed between a plane of the top surface of the piston 11 and the bottom surface of the cylinder cover, at least a portion of the axial cross section of the combustion chamber 13 is a trapezoidal shape, a portion of the semi-elliptical shape of the pit 12, where a circumscribed hexagon of the semi-elliptical shape of the axial cross section is tangent to the semi-elliptical shape of the axial cross section, is a first plane, and the trapezoidal shape of the hexagonal shape of the combustion chamber 13 and the first plane can be combined to form a hexagonal plane.

It can be understood that the pit 12 may be an ellipsoidal pit 12, or may be a cylindrical pit 12 with a semi-elliptical cross section along the axial direction of the piston 11, that is, two ends of the pit 12 are planes, and the axial cross section of the combustion chamber 13 corresponding to the pit 12 is trapezoidal, and according to the characteristics of the gas engine, the combustion chamber may be a four-valve (or two-valve) pentroof type combustion chamber, and the intake valve and the exhaust valve are respectively located on two sides of the axis. Because the gas engine is injected by an air inlet channel, the arrangement of an oil injector can be omitted, and the end surfaces where the air inlet channel port 15 and the exhaust channel port 16 are positioned form part of the side wall of the combustion cavity 13, so that in conclusion, the structures of the combustion cavity 13 and the pit 12 form a flow guide structure close to an ellipse, and airflow in the combustion chamber forms tumble flow.

The combustion system provided by the invention has the advantages that the combustion chamber is designed according to the elliptic trace of the outermost periphery of the tumble flow, the combustion chamber between the cylinder cover and the piston 11 is designed according to the elliptic trace of the outermost periphery of the tumble flow, the virtual ellipse is taken as a design reference, the smooth flow of gas entering the cylinder is ensured, the tumble flow is convenient to form, the wall surface heat transfer is reduced, the thermal efficiency is improved, the combustion chamber has a compact structure and a small heat dissipation area, the airflow movement in the cylinder is facilitated to be organized, the rapid and complete combustion of fuel is realized, and the purposes of improving the combustion speed of the gas engine and improving the thermal efficiency are finally achieved.

In some embodiments of the present invention, the trapezoidal axial cross section of the combustion chamber 13 and the semi-elliptical axial cross section of the pit 12 are symmetrical about the top surface of the piston 11, and the shape of the piston 11 is matched with the shape of the bottom of the cylinder cover, so that the overall shape of the combustion chamber is close to an ellipsoid, and under the action of the tangential air inlet channel, the loss of the generated tumble flow in the propagation process is reduced, and the tumble flow is broken at the top dead center to form stronger turbulent motion, so that the combustion rate is increased.

In some embodiments of the present invention, the length of the major axis of the semi-elliptical axial section of the pit 12 is 0.7 to 0.9 times the inner diameter of the cylinder liner 10, and the sum of the height of the trapezoidal axial section of the combustion chamber 13 and the height of the semi-elliptical axial section of the pit 12 is 0.5 to 0.75 times the inner diameter of the cylinder liner 10, so as to optimize the size design of the pit 12 and the combustion chamber 13 and improve the combustion effect of the combustion chamber.

In some embodiments of the present invention, the combustion chamber 13 includes a first chamber and a second chamber, the axial cross section of the first chamber is symmetrical to the first plane with respect to the top surface of the piston 11, the bottom of the second chamber is communicated with the first chamber, the cylinder head is provided with a spark plug 14 mounting hole corresponding to the top of the second chamber, the top of the combustion chamber is flattened on the basis of a roof-type combustion chamber, firstly, the spark plug 14 is conveniently mounted in the centrally arranged spark plug 14 mounting hole, secondly, the tumble flow dead zone is reduced, the airflow disturbance at the spark plug 14 is not too strong to ensure reliable ignition, and the periphery of the spark plug 14 is a high tumble zone to ensure flame propagation.

Further, the difference between the axial length of the first cavity and the axial length of the second cavity is greater than 3 mm, so that the airflow disturbance at the spark plug 14 is not too strong to ensure reliable ignition.

In some embodiments of the present invention, one or two air inlet ports 15 and one or two air outlet ports 16 are arranged on the bottom surface of the cylinder cover, the intake valve 17 is installed in the air inlet port 15, the exhaust valve 18 is installed in the air outlet port 16, the number of the air inlet ports 15 and the number of the air outlet ports 16 are equal, the air inlet ports 15 and the air outlet ports 16 are respectively arranged on two sides of the axis of the piston 11, the air inlet ports 15 and the air outlet ports 16 are symmetrical with respect to the axis of the piston 11, an arc-shaped transition structure 19 is arranged at the connection position of the concave pit 12 and the top surface of the piston 11, the arc-shaped transition structure 19 is arranged corresponding to the air outlet port 16, and the arc-shaped transition structure 19 is tangent to the concave pit 12.

Further, the arc radius of the arc transition structure 19 is 0.2 to 1.2 times the diameter of the dimple 12.

In some embodiments of the present invention, the top surface of the piston 11 corresponding to the air inlet port 15 is a plane, and the above structure can guide the clockwise tumble flow, and can obstruct the flow of air entering the cylinder from the lower end of the air inlet valve, so as to inhibit the formation of reverse tumble flow, and relatively strengthen the clockwise forward tumble flow.

A second aspect of the invention provides a gas engine comprising a combustion system which is an engine water jacket according to the first aspect of the invention.

The gas engine proposed by the second aspect of the present invention has the same advantageous effects as the combustion system proposed by the first aspect of the present invention, and thus, the description thereof is omitted.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.