A Combustion Chamber Structure of a Natural Gas Engine with a Flow Guide Plate

Abstract

An embodiment of the present application discloses a combustion chamber structure of a deflector-type natural gas engine, which is used to increase the turbulent kinetic energy above the combustion chamber pit, shorten the ignition delay period and the combustion duration during combustion, and widen the knock boundary. The method of the embodiment of the present application includes: a deflector structure, a combustion chamber pit, a piston body, and an intake passage; the deflector structure and the combustion chamber pit are formed on the piston top surface of the piston body; the intake passage is arranged above the combustion chamber pit, and the combustion chamber pit is used for the airflow to form an orderly moving vortex; during the squish process of the combustion chamber pit, the deflector structure is used to push the gas mixture flow towards the top surface of the combustion chamber pit.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of natural gas engine combustion chambers, and in particular, to a combustion chamber structure of a natural gas engine with a deflector plate type. Background Art

[0002] The combustion chamber structure of a natural gas engine has an obvious influence on the in-cylinder turbulence intensity. For example, the influence on the in-cylinder turbulence intensity can be enhanced by optimizing the combustion chamber shape and expanding the coverage range of the high-turbulence kinetic energy region. At present, most natural gas engines are developed by improving diesel engines. The natural gas engine uses the original volute air passage of the diesel engine, and the air passage performance is mainly based on swirl and supplemented by tumble.

[0003] Most of the existing combustion chambers of natural gas engines are straight cylinder types. After the piston is equipped with a spiral intake passage, large-scale vortices with orderly movement will be formed in the concave pit of the combustion chamber. Then, according to the position of the air passage, the rotation direction of the vortices is determined. At the end of the compression stroke, under the action of squish, the large-scale vortices in the concave pit of the combustion chamber are broken into small-scale vortex clusters. Since there is no guiding structure on the inner wall surface of the combustion chamber, the small-scale vortex clusters cannot be pushed above the concave pit of the combustion chamber, that is, near the spark plug, resulting in the turbulence kinetic energy near the spark plug being lower than that in the concave pit of the combustion chamber. This will increase the ignition delay period in the combustion chamber, slow down the flame propagation speed, increase the probability of spontaneous ignition of the remote mixture gas, and narrow the knock boundary. Summary of the Invention

[0004] The embodiments of the present application provide a combustion chamber structure of a natural gas engine with a deflector plate type, which is used to increase the turbulence kinetic energy above the concave pit of the combustion chamber, shorten the ignition delay period and the combustion duration during combustion, and widen the knock boundary.

[0005] The present application provides a combustion chamber structure of a natural gas engine with a deflector plate type, which is used for:

[0006] A deflector plate structure, a concave pit of the combustion chamber, a piston body, and an intake passage;

[0007] The deflector plate structure and the concave pit of the combustion chamber are formed on the piston top surface of the piston body;

[0008] The intake passage is arranged above the concave pit of the combustion chamber, and the concave pit of the combustion chamber is used for the airflow to form vortices with orderly movement;

[0009] During the squish process of the concave pit of the combustion chamber, the deflector plate structure is used to push the gas mixture flow towards the top surface of the concave pit of the combustion chamber.

[0010] Optionally, the deflector plate structure includes:

[0011] A flow-facing surface, an inclined surface, and a return flow surface;

[0012] The flow-facing surface is vertically disposed on the plane of the inner wall surface of the combustion chamber pit;

[0013] The inclined surface is connected to the flow-facing surface;

[0014] The flow-returning surface is connected to the inclined surface, and the flow-returning surface is used to reduce the air flow return area.

[0015] Optionally, the outer surface of the flow-returning surface is set as an arc surface.

[0016] Optionally, the range of the arc radius of the arc surface is set to 6 to 10 mm.

[0017] Optionally, the arc radius is greater than the other arc radii in the deflector structure.

[0018] Optionally, the range of the included angle between the flow-facing surface and the vertical direction of the center line connection of the two ends of the intake port is set to 45 to 90 degrees.

[0019] Optionally, the range of the ratio of the horizontal distance between the inclined surface and the side wall surface of the combustion chamber pit to the horizontal distance between the side wall surface of the combustion chamber pit and the center line of the combustion chamber pit is set to 0.5 to 0.65.

[0020] Optionally, the range of the included angle between the inclined surface and the bottom of the combustion chamber pit is set to 45 to 60 degrees.

[0021] Optionally, the range of the circumferential direction span angle of the inclined surface with the midpoint of the combustion chamber pit as the center of the circle is 45 to 180 degrees.

[0022] Optionally, the connection between the combustion chamber pit and the inclined surface is set to a rounded shape.

[0023] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0024] This application provides a deflector-type natural gas engine combustion chamber structure with a deflector structure, a combustion chamber pit, a piston body, and an intake port. The deflector structure and the combustion chamber pit form the piston top surface of the piston body. The intake port is disposed above the combustion chamber pit. This combustion chamber structure can increase the turbulent kinetic energy above the combustion chamber pit, shorten the ignition delay period and the combustion duration during combustion, and widen the knock boundary. Among them, the combustion chamber pit is used for the air flow to form an orderly moving eddy current, and the deflector structure is used to push the gas mixture flow to the top surface of the combustion chamber pit during the squish process of the combustion chamber pit. Brief Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of an embodiment of the deflector-type natural gas engine combustion chamber structure in the embodiment of the present application;

[0026] Figure 2 This is a schematic structural diagram of another embodiment of the combustion chamber structure of a deflector-type natural gas engine in the embodiments of the present application. Detailed implementation manners

[0027] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely elaborate on the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. 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.

[0028] Please refer to Figures 1 to 2 , in the embodiments of the present application, a deflector-type natural gas engine combustion chamber structure is provided, including: a deflector structure 1, a combustion chamber pit 2, a piston body, and an intake passage. The deflector structure 1 and the combustion chamber pit 2 are formed on the piston top surface of the piston body; the intake passage is arranged above the combustion chamber pit 2, and the combustion chamber pit 2 is used for the airflow to form an orderly moving eddy current; during the squish process of the combustion chamber pit 2, the deflector structure 1 is used to push the gas mixture airflow towards the top surface of the combustion chamber pit 2.

[0029] In the embodiments of the present application, a deflector-type natural gas engine combustion chamber structure is provided, having a deflector structure 1, a combustion chamber pit 2, a piston body, and an intake passage. This deflector-type natural gas engine combustion structure is used to increase the turbulent kinetic energy above the combustion chamber pit, shorten the ignition delay period and combustion duration during combustion, and widen the knock boundary.

[0030] In the present application, a deflector structure 1 is designed in the combustion chamber pit 2. The deflector structure 1 includes a flow-facing surface 21, an inclined surface 22, and a return surface 23. Among them, the flow-facing surface 21 is perpendicular to the plane of the inner wall surface of the combustion chamber pit 2, the inclined surface 22 is connected to the flow-facing surface 21, and the return surface 23 is connected to the inclined surface 22. Among them, the return surface 23 is used to reduce the airflow return area. It should be noted that since an airflow return area will be formed near the return surface 23, the outer surface of the return surface 23 needs to be designed as an arc surface, and the radius range of this arc surface is set to 6 to 10 mm. The arc radius of this arc surface here is greater than the other arc radii in the deflector structure 1, and the other arc radii are generally 2 to 3 mm. In addition to the full arc surface, the outer surface of the return surface 23 can also be designed as a structure combining an arc surface and a plane.

[0031] Since the intake passage bifurcates into two air passages as the air flow outlets in the combustion chamber structure, the center point of the combustion chamber pit 2 can be used as a reference point, and the near and far ends of the air passages can be determined according to the distance between each air passage and this reference point. For example, the end outlet farther from the center point can be called the far end outlet 24, and the end outlet closer to the center point can be called the near end outlet 25.

[0032] Optionally, the included angle range between the upstream face 21 and the connecting line of the center lines of the two ends of the intake passage in the vertical direction is set to 45 to 90 degrees, and this included angle A1 is as Figure 1 shown. Preferably, the position of the upstream face 21 can be set directly below the far end outlet 24 of the intake passage. The included angle range of the inclined face 22 in the circumferential direction with the center of the combustion chamber pit 2 as the center is set to 45 to 180 degrees, and this included angle A2 of the span is as Figure 1 shown.

[0033] Please refer to Figure 2 , in order to make the connection between planes smoother, the ratio range of the horizontal distance L1 between the inclined face 22 and the inner wall surface of the combustion chamber pit 2 to the horizontal distance L2 between the inner wall surface of the combustion chamber pit 2 and the center line of the combustion chamber pit 2 can be set to 0.5 to 0.65. Preferably, the ratio can be controlled at 0.55. The included angle A3 between the inclined face 22 and the bottom of the combustion chamber pit 2 is in the range of 45 to 60 degrees. Preferably, this angle can be set to 55 degrees, and the connection between the combustion chamber pit 2 and the inclined face 22 is set to be rounded. Further, for the connection between the inclined face 22 and the inner wall surface and the bottom of the combustion chamber, it can be transitioned through a fillet, and the fillet radius generally does not exceed 3 mm.

[0034] It should be particularly noted that there is at least 1 deflector structure 1 mentioned in this application. When the number of deflector structures 1 is greater than 1, the total lengths of the deflector structures 1 can be unequal, and the distances between the deflector structures 1 can be unequal. Preferably, the total lengths of the deflector structures 1 are equal, and the distances between the deflector structures 1 are equal. The specific lengths and distances are not limited here.

[0035] In the embodiment of this application, when the gas mixture enters the combustion chamber pit 2 from the far end outlet and the near end outlet of the intake passage, the air flow in the combustion chamber pit 2 moves along the inner wall surface, breaking the orderliness of the eddy current movement. The gas mixture enters the combustion chamber pit 2 from the far end outlet 24 and the near end outlet 25 of the intake passage, and the air flow in the pit will determine the corresponding movement direction according to the position of the intake passage and perform eddy current movement along this direction.

[0036] During the operation of the deflector-type natural gas engine combustion chamber of the present invention, the piston body in the engine combustion chamber moves upward, and the flowing air will impact the upstream surface 21, thereby changing the direction of the air flow. Under the action of squish flow, the fuel-air mixture enters the combustion chamber pit 2. Under the guiding action of the inclined surface 22, the air flow is pushed above the combustion chamber pit 2 and close to the vicinity of the spark plug, thereby increasing the turbulent kinetic energy of the combustion chamber pit 2. It should be particularly noted that during the process of the air flow changing its direction of motion, the orderliness of the eddy motion is broken, so that after the air flow hits the wall, the large-scale eddies break into small-scale vortex clusters. After the air flow changes its direction of motion, the high-turbulent kinetic energy region can also be pushed above the combustion chamber pit 2, that is, near the spark plug, shortening the ignition delay period and the combustion duration, reducing the probability of spontaneous ignition of the distal mixer, and widening the knock boundary.

[0037] In addition, if the rotation direction of the eddy current mentioned above changes, the upstream surface 21 and the return surface 23 are transposed.

Claims

1. A combustion chamber structure of a deflector - type natural gas engine, characterized in that, it includes: a deflector structure, a combustion chamber pit, a piston body, and an air inlet passage; the deflector structure and the combustion chamber pit are formed on the piston top surface of the piston body; the air inlet passage is arranged above the combustion chamber pit, and the combustion chamber pit is used for the airflow to form an orderly - moving eddy current; during the squish process of the combustion chamber pit, the deflector structure is used to push the gas - air mixture flow towards the top surface of the combustion chamber pit; the deflector structure includes: a flow - facing surface, an inclined surface, and a return flow surface; the flow - facing surface is vertically arranged on the plane of the inner wall surface of the combustion chamber pit; one end of the inclined surface is connected to the flow - facing surface; the return flow surface is connected to the other end of the inclined surface, and the return flow surface is used to reduce the airflow return area; the outer surface of the return flow surface is set as an arc surface, and the span angle range of the inclined surface in the circumferential direction with the mid - point of the combustion chamber pit as the center of the circle is set to 45 to 180 degrees.

2. The combustion chamber structure according to claim 1, characterized in that, the arc radius range of the arc surface is set to 6 to 10 mm.

3. The combustion chamber structure according to claim 1, characterized in that, the included - angle range between the flow - facing surface and the center - line connection of the two ends of the air inlet passage in the vertical direction is set to 45 to 90 degrees.

4. The combustion chamber structure according to claim 3, characterized in that, the ratio range of the horizontal distance between the inclined surface and the side - wall surface of the combustion chamber pit to the horizontal distance between the side - wall surface of the combustion chamber pit and the center - line of the combustion chamber pit is set to 0.5 to 0.

65.

5. The combustion chamber structure according to claim 4, characterized in that, the included - angle range between the inclined surface and the bottom of the combustion chamber pit is set to 45 to 60 degrees.

6. The combustion chamber structure according to any one of claims 2 to 5, characterized in that, the connection part between the combustion chamber pit and the inclined surface is set as a rounded - corner type.

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