Steel piston construction for heavy-duty gas engines

Abstract

The present invention discloses a steel piston structure of a heavy-duty gas engine. The combustion chamber of the steel piston adopts a constriction structure. The combustion chamber includes a throat arc, a bottom arc and a bottom center arc. The throat arc is arranged at the top of the combustion chamber, and the upper part of the throat arc is connected with the piston top surface through a transition slope. The bottom arc is arranged below the throat arc, and the lower part of the throat arc is connected with the upper part of the bottom arc through a straight line. The bottom center arc is arranged at the bottom of the combustion chamber, and the bottom center arc bulges toward the throat. The ratio of the throat diameter to the piston outer diameter is between 50% and 60%, and the ratio of the throat diameter to the maximum diameter of the combustion chamber is between 65% and 75%. The steel piston structure of the heavy-duty gas engine of the present invention adopts a constriction structure, so that the mixed gas can be fully mixed to make the combustion more complete.

Description

Technical Field

[0001] The invention relates to the field of gas engines, in particular to a steel piston structure of a heavy-duty gas engine capable of meeting equivalent combustion requirements. Background Art

[0002] like Figure 1 As shown, the piston combustion chamber of the gas engine of the prior art is basically a straight barrel type with a relatively small necking. After the mixed gas enters the combustion chamber, a mixed flow cannot be formed, and a more excess air coefficient is required to burn the gas completely. However, too much air is not conducive to the subsequent combustion, and the ignition delay period becomes longer, thereby increasing the emission of carbon smoke.

[0003] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] The object of the present invention is to provide a steel piston structure for a heavy-duty gas engine, which adopts a constriction structure so that the mixed gas can be fully mixed to make the combustion more complete.

[0005] To achieve the above-mentioned purpose, the present invention provides a steel piston structure for a heavy-duty gas engine, wherein the combustion chamber of the steel piston adopts a tapered structure, and the combustion chamber comprises a throat arc, a bottom arc and a bottom center arc; the throat arc is arranged at the top of the combustion chamber, and the upper part of the throat arc is connected with the piston top surface through a transition slope; the bottom arc is arranged below the throat arc, and the lower part of the throat arc is connected with the upper part of the bottom arc through a straight line; the bottom center arc is arranged at the bottom of the combustion chamber, and the bottom center arc bulges toward the throat; wherein the ratio of the throat diameter to the piston outer diameter is between 50% and 60%, and the ratio of the throat diameter to the maximum diameter of the combustion chamber is between 65% and 75%.

[0006] In a preferred embodiment, the distance from the center of the throat arc to the top surface of the piston is between 4 mm and 5 mm.

[0007] In a preferred embodiment, the ratio of the distance from the center of the throat arc to the piston top surface to the depth of the combustion chamber is between 10% and 15%.

[0008] In a preferred embodiment, the steel piston structure of the heavy-duty gas engine further includes an internal cooling oil gallery which is arranged around the combustion chamber.

[0009] In a preferred embodiment, the distance from the top of the internal cooling oil channel to the top surface of the piston is between 4 mm and 7 mm.

[0010] In a preferred embodiment, in the axial cross section of the combustion chamber, the angle between the lines connecting the lower part of the throat arc and the upper part of the bottom arc is between 60° and 75°.

[0011] In a preferred embodiment, the radius of the bottom center arc is between 80 mm and 100 mm.

[0012] In a preferred embodiment, the angle between the transition slope and the piston top surface is between 10° and 15°.

[0013] In a preferred embodiment, the radius of the throat arc is between 3 mm and 5 mm, and the radius of the bottom arc is between 20 mm and 30 mm.

[0014] Compared with the prior art, the steel piston structure of the heavy-duty gas engine of the present invention has the following beneficial effects: due to the use of a constricted structure in the combustion chamber, under the action of the rear port, after the mixed gas enters the combustion, the speed will be accelerated, and it will enter the bottom arc along the angle A°, and because the bottom arc diameter (the maximum diameter of the combustion chamber) is larger than the throat diameter, coupled with the convex peak of the bottom center arc, the mixed gas is very easy to form a vortex here, so that the mixed gas can be fully mixed, so the combustion will be more complete, which not only reduces the emission of carbon smoke, but also reduces the demand for air volume, and realizes equivalent combustion. Furthermore, since the distance from the top of the internal cooling oil channel to the top surface of the piston is relatively small, the temperature at the throat arc can be further reduced, which can prevent the throat from cracking due to excessive temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a straight-through combustion chamber according to an embodiment of the prior art;

[0016] Figure 2 is a schematic diagram of the direction of the mixed airflow of the constricted combustion chamber according to one embodiment of the present invention;

[0017] Figure 3 It is a schematic structural diagram of a constricted combustion chamber according to one embodiment of the present invention.

[0018] Description of main reference numerals:

[0019] H1-depth of combustion chamber, H2-distance from the center of throat arc to the top of piston, H3-distance from the top of internal cooling oil channel to the top of piston, φ1-throat diameter, φ2-maximum diameter of combustion chamber, φ3-outer diameter of piston, Ra-radius of throat arc, Rb-radius of bottom arc, Rc-radius of bottom center arc, A°-angle between throat arc and bottom arc, B°-angle between transition slope and top of piston. DETAILED DESCRIPTION

[0020] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0021] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0022] like Figures 2 to 3 As shown, according to a steel piston structure of a heavy-duty gas engine in a preferred embodiment of the present invention, the combustion chamber of the steel piston knot adopts a constricted structure, and the combustion chamber includes a throat arc, a bottom arc, and a bottom center arc. The throat arc is arranged at the top of the combustion chamber, and the upper part of the throat arc is connected to the piston top surface through a transition slope. The bottom arc is arranged below the throat arc, and the lower part of the throat arc is connected to the upper part of the bottom arc by a straight line. The bottom center arc is arranged at the bottom of the combustion chamber, and the bottom center arc bulges toward the throat.

[0023] See also Figure 3 In some embodiments, the ratio of the throat diameter φ1 to the piston outer diameter φ3 is between 50% and 60%, and the ratio of the throat diameter φ1 to the maximum diameter φ2 of the combustion chamber is between 65% and 75%. The distance H2 from the center of the throat arc to the top surface of the piston is between 4 mm and 5 mm. The ratio of the distance H2 from the center of the throat arc to the top surface of the piston to the depth H1 of the combustion chamber is between 10% and 15%.

[0024] In some embodiments, the steel piston structure of the heavy-duty gas engine further includes an inner cooling oil channel, which is arranged around the combustion chamber. The distance H3 from the top of the inner cooling oil channel to the top surface of the piston is between 4 mm and 7 mm.

[0025] In some embodiments, in the axial section of the combustion chamber, the angle A° between the lower part of the throat arc and the upper part of the bottom arc is between 60° and 75°, and the radius Rc of the bottom center arc is between 80 mm and 100 mm.

[0026] In some embodiments, the angle between the transition slope and the piston top surface is between 10° and 15°, and the transition slope serves to guide the mixed gas into the combustion chamber.

[0027] In some embodiments, in order to prevent thermal stress cracking at the throat, the throat arc radius Ra should not be too small. However, if the throat arc radius Ra is too large, the vortex formed at the throat arc Rb will produce turbulence, making the combustion unstable. Therefore, the throat arc radius is generally between 3mm and 5mm. If the bottom arc radius Rb is too small, the vortex formed is not enough. If it is too large, it will occupy the space of the inner cooling oil channel, thereby affecting the layout of the oil channel, making the inner cooling oil channel difficult to arrange and reducing the wall thickness. Therefore, the bottom arc radius is generally between 20mm and 30mm.

[0028] See also Figure 2 In some embodiments, the combustion principle of the steel piston structure of the heavy-duty gas engine of the present invention is as follows: after the mixed gas enters the combustion chamber, it must first pass through the necking structure at the throat arc. Since a bottom arc is provided below the throat arc, and the diameter of the bottom arc is greater than the diameter at the throat, and the lower part of the throat arc and the upper part of the bottom arc are connected by a straight line, the mixed gas can be guided to flow downward from the throat arc along the bottom arc. At this time, the mixed gas will encounter the bottom center arc. Since the bottom center arc is a protruding arc toward the center direction of the necking, the mixed gas will form a vortex toward the bottom arc after encountering the protruding bottom center arc. At this time, the mixed gas can be more fully mixed again, thereby making the combustion more complete, thereby reducing carbon emissions. Furthermore, from Figure 1 and Figure 2 It can be clearly seen from the comparison that the distance from the top of the inner cooling oil channel to the top surface of the piston of the present invention is significantly smaller than that of the prior art, which can further reduce the temperature at the arc of the throat and prevent the throat from cracking due to excessive temperature.

[0029] In summary, the steel piston structure of the heavy-duty gas engine of the present invention has the following advantages: due to the constriction structure adopted in the combustion chamber, under the action of the rear port, after the mixed gas enters the combustion, the speed will be accelerated, and it will enter the bottom arc along the angle A°, and because the bottom arc diameter (the maximum diameter of the combustion chamber) is larger than the throat diameter, coupled with the convex peak of the bottom center arc, the mixed gas is very easy to form a vortex here, so that the mixed gas can be fully mixed, so the combustion will be more complete, which not only reduces the emission of carbon smoke, but also reduces the demand for air volume, and realizes equivalent combustion. Furthermore, since the distance from the top of the internal cooling oil channel to the top surface of the piston is relatively small, the temperature at the throat arc can be further reduced, which can prevent the throat from cracking due to excessive temperature.

[0030] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A steel piston structure for a heavy-duty gas engine, characterized in that: The combustion chamber of the steel piston knot adopts a constricted structure, and the combustion chamber comprises: A throat arc is arranged at the top of the combustion chamber, and the upper part of the throat arc is connected with the top surface of the piston through a transition slope; a bottom arc, which is disposed below the throat arc, wherein a lower portion of the throat arc is connected to an upper portion of the bottom arc by a straight line; and A bottom center arc, which is arranged at the bottom of the combustion chamber, and the bottom center arc is convex toward the throat; The ratio of the throat diameter to the piston outer diameter is between 50% and 60%, and the ratio of the throat diameter to the maximum diameter of the combustion chamber is between 65% and 75%; The distance from the center of the throat arc to the top surface of the piston is between 4 mm and 5 mm; wherein the ratio of the distance from the center of the throat arc to the piston top surface to the depth of the combustion chamber is between 10% and 15%; Wherein, in the axial cross section of the combustion chamber, the angle between the lines connecting the lower part of the throat arc and the upper part of the bottom arc is between 60° and 75°; The radius of the bottom center arc is between 80 mm and 100 mm; The angle between the transition slope and the piston top surface is between 10° and 15°; The radius of the throat arc is between 3 mm and 5 mm, and the radius of the bottom arc is between 20 mm and 30 mm; When the mixed gas enters the combustion chamber, it first passes through the necking structure at the throat arc. Since a bottom arc is arranged below the throat arc, and the diameter of the bottom arc is larger than the diameter of the throat, and the lower part of the throat arc and the upper part of the bottom arc are connected by a straight line, the mixed gas can be guided to flow downward from the throat arc along the bottom arc. At this time, the mixed gas will encounter the bottom center arc. Since the bottom center arc is a convex arc toward the center direction of the necking, the mixed gas will form a vortex toward the bottom arc after encountering the convex bottom center arc. At this time, the mixed gas will be more fully mixed again, thereby making the combustion more complete, thereby reducing carbon emissions.

2. The steel piston structure of a heavy-duty gas engine according to claim 1, characterized in that: It also includes an inner cooling oil channel, which is arranged around the combustion chamber.

3. The steel piston structure of a heavy-duty gas engine according to claim 2, characterized in that: The distance from the top of the inner cooling oil channel to the top surface of the piston is between 4 mm and 7 mm.

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